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TECHNOLOGY, ENERGY EFFICIENCY AND<br />
ENVIRONMENTAL EXTERNALITIES IN THE PULP<br />
AND PAPER INDUSTRY<br />
RAW MATERIAL<br />
PREPARATION<br />
PULPING<br />
Χ Chemical Pulping<br />
Alkaline<br />
- Kraft or sulfate √<br />
- Soda pulping<br />
Acidic or sulfite<br />
Χ Mechanical<br />
- GWP - RMP<br />
- TMP - CTMP<br />
Χ Semi-chemical Pulping<br />
- Neutral sulfite<br />
BLEACHING<br />
PAPER MAKING<br />
220-300 kWh/t<br />
400-520 kWh/t<br />
Electricity<br />
Steam<br />
(180°C,<br />
12-13 GJ/t)<br />
Electricity<br />
Steam<br />
(5 GJ/t)<br />
Electricity<br />
Electricity<br />
Steam<br />
(5-6 GJ/t)<br />
Steam<br />
(8 GJ/t)<br />
Electricity<br />
Pulp & Paper Industry<br />
Energy Flow<br />
Effluents & Emissions<br />
Raw Materials<br />
(Conventional: Wood<br />
O<strong>th</strong>ers: Grass,<br />
Bagasse, Straw etc.)<br />
Chipper<br />
Debarked Wood / Woodchips<br />
Pulp Digester<br />
Crude Pulp<br />
Screening &<br />
Washing<br />
Fine Purified Pulp<br />
Thickening<br />
Unble<strong>ac</strong>hed Pulp<br />
Ble<strong>ac</strong>hing<br />
Ble<strong>ac</strong>hed pulp<br />
Stock<br />
Preparation<br />
Paper M<strong>ac</strong>hine<br />
Drying &<br />
Finishing<br />
Finished Paper<br />
Products<br />
Waste paper<br />
(secondary<br />
intake)<br />
Refining<br />
Raw Materials<br />
(Conventional: Wood<br />
O<strong>th</strong>ers: Grass,<br />
Bagasse, Straw etc.)<br />
Chipper<br />
Debarked Wood / Woodchips<br />
Pulp Digester<br />
Crude Pulp<br />
Screening &<br />
Washing<br />
Thickening<br />
Unble<strong>ac</strong>hed Pulp<br />
Ble<strong>ac</strong>hing Plant<br />
Ble<strong>ac</strong>hed pulp<br />
Stock<br />
Preparation<br />
Paper M<strong>ac</strong>hine<br />
Drying &<br />
Finishing<br />
Finished Paper<br />
Products<br />
School <strong>of</strong> Environment, R<br />
<strong>Asian</strong> Institut<br />
Bangkok<br />
Weak bl<strong>ac</strong>k liquor<br />
Sedimentation &<br />
Aerobic<br />
treatment<br />
Evaporator<br />
to pulp digester<br />
Fine Purified Pulp<br />
Chemical reuse<br />
Chemical<br />
recovery boiler<br />
Sludge,<br />
Ble<strong>ac</strong>h water<br />
Waste paper<br />
(secondary<br />
intake)<br />
Refining<br />
Heat emission<br />
White water,<br />
Fiber, Fillers,<br />
Broke, etc.<br />
Liquid clean-up,<br />
Broke, Coatings<br />
etc.<br />
to Treatment plants<br />
Evaporative emission<br />
Strong bl<strong>ac</strong>k liquor<br />
toCombustion<br />
School <strong>of</strong> Environment, Resources and Development<br />
<strong>Asian</strong> <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong><br />
Bangkok - Thailand<br />
ASIAN INSTITUTE<br />
OF TEC HN OLOGY<br />
19 5 9<br />
Condensat<br />
Gaseseous e<br />
emission<br />
Effluent<br />
Fiber & ink<br />
sludge<br />
to<br />
Anaerobic<br />
treatment
TECHNOLOGY, ENERGY EFFICIENCY AND<br />
ENVIRONMENTAL EXTERNALITIES IN THE PULP<br />
AND PAPER INDUSTRY<br />
RAW MATERIAL<br />
PREPARATION<br />
PULPING<br />
Χ Chemical Pulping<br />
Alkaline<br />
- Kraft or sulfate √<br />
- Soda pulping<br />
Acidic or sulfite<br />
Χ Mechanical<br />
- GWP - RMP<br />
- TMP - CTMP<br />
Χ Semi-chemical Pulping<br />
- Neutral sulfite<br />
BLEACHING<br />
PAPER M AKING<br />
220-300 kWh/t<br />
400-520 kWh/t<br />
Electricity<br />
Steam<br />
(180°C,<br />
12-13 GJ/t)<br />
Electricity<br />
Steam<br />
(5 GJ/t)<br />
Electricity<br />
Electricity<br />
Steam<br />
(5-6 GJ/t)<br />
Steam<br />
(8 GJ/t)<br />
Electricity<br />
Pulp & Paper Industry<br />
Energy Flow<br />
Effluents & Emissions<br />
Raw Materials<br />
(Conventional: Wood<br />
O<strong>th</strong>ers: Grass, Bagasse,<br />
Straw etc.)<br />
Chipper<br />
Debarked Wood / Woodchips<br />
Pulp Digester<br />
Crude Pulp<br />
Screening &<br />
Washing<br />
Fine Purified Pulp<br />
Thickening<br />
Unble<strong>ac</strong>hed Pulp<br />
Ble<strong>ac</strong>hing<br />
Ble<strong>ac</strong>hed pulp<br />
Stock<br />
Preparation<br />
Paper M<strong>ac</strong>hine<br />
Drying &<br />
Finishing<br />
Finished Paper<br />
Products<br />
Waste paper<br />
(secondary intake)<br />
Refining<br />
to pulp digester<br />
Brahmanand Mohanty<br />
Raw Materials<br />
(Conventional: Wood<br />
O<strong>th</strong>ers: Grass, Bagasse,<br />
Straw etc.)<br />
Debarked Wood / Woodchips<br />
School <strong>of</strong> Environment, Resources and Development<br />
<strong>Asian</strong> <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong><br />
Bangkok - Thailand<br />
Chipper<br />
Pulp Digester<br />
Crude Pulp<br />
Screening &<br />
Washing<br />
Thickening<br />
Unble<strong>ac</strong>hed Pulp<br />
Ble<strong>ac</strong>hing Plant<br />
Ble<strong>ac</strong>hed pulp<br />
Stock<br />
Preparation<br />
Paper M<strong>ac</strong>hine<br />
Drying &<br />
Finishing<br />
Finished Paper<br />
Products<br />
Weak bl<strong>ac</strong>k liquor<br />
Evaporator<br />
Fine Purified Pulp<br />
Chemical reuse<br />
Chemical<br />
recovery boiler<br />
Sedimentation &<br />
Aerobic treatment<br />
Sludge,<br />
Ble<strong>ac</strong>h water<br />
Waste paper<br />
(secondary intake)<br />
Refining<br />
Heat emission<br />
White water,<br />
Fiber, Fillers,<br />
Broke, etc.<br />
Liquid clean-up,<br />
Broke, Coatings etc.<br />
to Treatment plants<br />
Evaporative emission<br />
Strong bl<strong>ac</strong>k liquor<br />
to Combustion<br />
Condensate<br />
Gaseseous emission<br />
Effluent<br />
Fiber & ink<br />
sludge<br />
to Anaerobic<br />
treatment
<strong>Technology</strong>, Energy Efficiency and Environmental Externalities<br />
in <strong>th</strong>e Pulp and Paper Industry<br />
© <strong>Asian</strong> <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong>, 1997<br />
Edited by Brahmanand Mohanty<br />
Published by School <strong>of</strong> Environment, Resources and Development<br />
<strong>Asian</strong> <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong><br />
P.O. Box 4, Pa<strong>th</strong>um<strong>th</strong>ani 12120<br />
Thailand<br />
e-mail: visu@<strong>ait</strong>.<strong>ac</strong>.<strong>th</strong><br />
NOTICE<br />
Nei<strong>th</strong>er <strong>th</strong>e Swedish International Development Cooperation Agency (Sida) nor <strong>th</strong>e <strong>Asian</strong><br />
<strong>Institute</strong> <strong>of</strong> <strong>Technology</strong> (AIT) makes any warranty, expressed or implied, or assume any<br />
legal liability for <strong>th</strong>e <strong>ac</strong>cur<strong>ac</strong>y, completeness, or usefulness <strong>of</strong> any information, appratus,<br />
product, or represents <strong>th</strong>at its use would not infringe privately owned rights. Reference<br />
herein to any trademark, or manuf<strong>ac</strong>turer, or o<strong>th</strong>erwise does not constitute or imply its<br />
endorsement, recommendation, or favoring by Sida or AIT.<br />
ISBN 974 - 8256 - 72 - 3<br />
Printed in India by All India Press, Pondicherry.
FOREWORD<br />
The use <strong>of</strong> fossil fuels leads to <strong>th</strong>e emission <strong>of</strong> so-called "Green House Gases (GHG)", a<br />
concept which comprises carbon dioxide, nitrous oxides, sulfur oxides, etc. In recent years,<br />
a good deal <strong>of</strong> research has provided enough material to put forward <strong>th</strong>e claim <strong>th</strong>at a big<br />
increase in <strong>th</strong>e concentration <strong>of</strong> carbon dioxide in <strong>th</strong>e atmosphere would lead to a rise in<br />
<strong>th</strong>e average global temperature, wi<strong>th</strong> negative consequences for <strong>th</strong>e global climate. This<br />
claim has been confirmed by <strong>th</strong>e United Nations Intergovernmental Panel on Climate<br />
Change (IPCC) in its second scientific assessment published in 1996.<br />
Global warming can have catastrophic imp<strong>ac</strong>t on human and global security: island nations<br />
and low lying coastal regions would be permanently drowned by <strong>th</strong>e rise in <strong>th</strong>e level <strong>of</strong> <strong>th</strong>e<br />
oceans brought on by <strong>th</strong>e melting <strong>of</strong> polar ice; drought would become widespread; and<br />
desertification would expand and <strong>ac</strong>celerate. Persistent famines, mass migrations and largescale<br />
conflict would be <strong>th</strong>e result. Agriculture, food and water security, and international<br />
trade would come under severe strain.<br />
Until recently, industrialized countries have <strong>ac</strong>counted for most <strong>of</strong> <strong>th</strong>e emission <strong>of</strong> <strong>th</strong>e<br />
GHG, in particular carbon dioxide, because <strong>th</strong>eir economic development has been very<br />
strongly based on <strong>th</strong>e use <strong>of</strong> fossil fuels. However, <strong>th</strong>e same dynamic has also led to a<br />
situation where <strong>th</strong>e newly industrializing countries <strong>of</strong> Asia and Latin America (<strong>th</strong>e strong<br />
Sou<strong>th</strong>) are today contributing significantly to <strong>th</strong>e emission <strong>of</strong> carbon dioxide. This tendency<br />
will spread to and encompass an increasing number <strong>of</strong> developing countries unless bo<strong>th</strong><br />
<strong>th</strong>e industrialized and <strong>th</strong>e developing countries jointly agree on implementing <strong>th</strong>e measures<br />
to halt and <strong>th</strong>en reverse <strong>th</strong>e global trend towards a rapid rise in <strong>th</strong>e emission <strong>of</strong> carbon<br />
dioxide. That is <strong>th</strong>e central purpose <strong>of</strong> <strong>th</strong>e IPCC, which has succeeded in obtaining<br />
commitments from most <strong>of</strong> <strong>th</strong>e industrialized countries to reduce <strong>th</strong>eir emissions <strong>of</strong> carbon<br />
dioxide.<br />
At <strong>th</strong>e 1995 meeting in Berlin <strong>of</strong> <strong>th</strong>e Conference <strong>of</strong> <strong>th</strong>e Parties (CoP) to <strong>th</strong>e United<br />
Nations Climate Convention, it was decided to initiate negotiations to streng<strong>th</strong>en <strong>th</strong>e<br />
emission-reduction measures by <strong>th</strong>e industrialized countries, as well as countries <strong>of</strong> Eastern<br />
Europe and <strong>th</strong>e Former Soviet Union. The final negotiations are planned to take pl<strong>ac</strong>e at<br />
<strong>th</strong>e December 1997 meeting in Kyoto <strong>of</strong> <strong>th</strong>e CoP, which ought to result in legal<br />
instruments to ensure <strong>th</strong>at <strong>th</strong>e agreed measures are being fulfilled.<br />
The fossil fuel generated climate problem is very complex, wi<strong>th</strong> strong vested interests and<br />
special alliances. There is still considerable skepticism in <strong>th</strong>e developing world about <strong>th</strong>e<br />
need for measures to counter global warming, in particular in <strong>th</strong>e strong Sou<strong>th</strong>, which in no<br />
way wants to jeopardize its own rapid economic development. It is <strong>th</strong>erefore imperative to<br />
find innovative solutions, bo<strong>th</strong> technical and institutional, to <strong>th</strong>e climate problem, which<br />
are <strong>ac</strong>ceptable to bo<strong>th</strong> <strong>th</strong>e Nor<strong>th</strong> and <strong>th</strong>e Sou<strong>th</strong>. Meeting <strong>th</strong>is challenge calls for inter alia<br />
research programs <strong>th</strong>at t<strong>ac</strong>kle <strong>th</strong>e technological, techno-economic and policy problems in
promoting <strong>th</strong>e transition to decreasing use <strong>of</strong> fossil fuels, increasing energy efficiency and<br />
fuel substitution, and carbon recycling systems <strong>of</strong> energy production and use.<br />
The <strong>Asian</strong> Regional Research Programme on Energy, Environment and Climate<br />
(ARRPEEC) is part <strong>of</strong> <strong>th</strong>is global effort, which Sida is very pleased to have initiated and is<br />
fully supporting. The ARRPEEC comprises technological, techno-economic and policy<br />
research on energy efficiency, fuel substitution and carbon recycling in <strong>th</strong>e principal<br />
economic sectors <strong>of</strong> East, Sou<strong>th</strong>east and Sou<strong>th</strong> <strong>Asian</strong> countries.<br />
M R Bhagavan<br />
Senior Research Adviser, Department for Research Cooperation<br />
Swedish International Development Cooperation Agency, Sida
PREFACE<br />
Industries have always played a crucial role in <strong>th</strong>e socio-economic development <strong>of</strong> a<br />
country. They have contributed primarily to increased prosperity, greater employment and<br />
livelihood opportunities. On <strong>th</strong>e o<strong>th</strong>er hand, industries are <strong>ac</strong>cused <strong>of</strong> <strong>ac</strong>celerating <strong>th</strong>e<br />
consumption <strong>of</strong> scarce fossil fuels and <strong>of</strong> polluting <strong>th</strong>e local, regional, and global<br />
environment by releasing solid, liquid and gaseous pollutants to <strong>th</strong>eir surroundings.<br />
Experiences gained worldwide have shown <strong>th</strong>at <strong>th</strong>ese imp<strong>ac</strong>ts <strong>of</strong> industries on resource use<br />
and <strong>th</strong>e environment can be contained <strong>th</strong>rough more efficient production processes and<br />
adoption <strong>of</strong> cleaner technologies and procedures. Thus, fossil fuel consumption can be cut<br />
down drastically and waste generation can be avoided or minimized to <strong>th</strong>e lowest possible<br />
level. Regulatory regimes introduced in several countries have led <strong>th</strong>e industries to adopt<br />
appropriate measures. Some countries have adopted economic instruments to reflect <strong>th</strong>e<br />
true cost <strong>of</strong> goods and services by internalizing <strong>th</strong>e environmental costs <strong>of</strong> <strong>th</strong>eir input,<br />
production, use, recycling and disposal.<br />
The improvement <strong>of</strong> production system <strong>th</strong>rough <strong>th</strong>e use <strong>of</strong> technologies and processes <strong>th</strong>at<br />
utilize resources more efficiently and <strong>ac</strong>hieve “more wi<strong>th</strong> less” is an important pa<strong>th</strong>way<br />
towards <strong>th</strong>e long-term sustenance <strong>of</strong> industries. It is in <strong>th</strong>is context <strong>th</strong>at a research project<br />
was undertaken by <strong>th</strong>e <strong>Asian</strong> <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong> (AIT), wi<strong>th</strong> <strong>th</strong>e support <strong>of</strong> <strong>th</strong>e<br />
Swedish International Development Cooperation Agency (Sida). The project entitled<br />
“Development <strong>of</strong> Energy Efficient and Environmentally Sound Industrial Technologies in<br />
Asia” was launched wi<strong>th</strong> <strong>th</strong>e specific objective to enhance <strong>th</strong>e synergy among selected<br />
<strong>Asian</strong> developing countries in <strong>th</strong>eir efforts to grasp <strong>th</strong>e mechanism and various aspects<br />
related to <strong>th</strong>e adoption and propagation <strong>of</strong> energy efficient and environmentally sound<br />
technologies. Three energy intensive and environmentally polluting industrial sub-sectors<br />
(cement, iron & steel, and pulp & paper) and four <strong>Asian</strong> countries <strong>of</strong> varying sizes, political<br />
systems and stages <strong>of</strong> development (China, India, Philippines, Sri Lanka) were selected in<br />
<strong>th</strong>e framework <strong>of</strong> <strong>th</strong>is study. To enhance in-country cap<strong>ac</strong>ity building in <strong>th</strong>e subject matter,<br />
collaboration was sought from reputed national institutes who nominated experts to<br />
<strong>ac</strong>tively participate in <strong>th</strong>e execution <strong>of</strong> <strong>th</strong>e project.<br />
The <strong>ac</strong>tivities undertaken in <strong>th</strong>e first phase <strong>of</strong> <strong>th</strong>e project were <strong>th</strong>e following:<br />
- Evaluation <strong>of</strong> <strong>th</strong>e status <strong>of</strong> technologies in selected energy intensive and<br />
environmentally polluting industries;<br />
- Identification <strong>of</strong> potential areas for energy conservation and pollution abatement<br />
in <strong>th</strong>ese industries;<br />
- Analysis <strong>of</strong> <strong>th</strong>e technological development <strong>of</strong> energy intensive and polluting<br />
industries in relation wi<strong>th</strong> <strong>th</strong>e national regulatory measures;<br />
- Identification <strong>of</strong> major barriers to efficiency improvements and pollution<br />
abatement in <strong>th</strong>e industrial sector.
Based on <strong>th</strong>e initial guidelines prepared at AIT under <strong>th</strong>e leadership <strong>of</strong> Dr. X. Chen,<br />
discussions were held wi<strong>th</strong> <strong>th</strong>e experts from <strong>th</strong>e national research institutes (NRIs) <strong>of</strong> <strong>th</strong>e<br />
four participating countries. The outcomes <strong>of</strong> <strong>th</strong>ese meetings were used as a basis for <strong>th</strong>e<br />
preparation <strong>of</strong> country reports which were presented at two project workshops held at<br />
Manila in May 1995 and at Bangkok in November 1995. On <strong>th</strong>e basis <strong>of</strong> <strong>th</strong>e reports<br />
submitted, cross-country comparison reports were prepared at AIT and additional relevant<br />
information was sought from <strong>th</strong>e NRIs to bridge some <strong>of</strong> <strong>th</strong>e gaps found in <strong>th</strong>eir<br />
respective reports. This is <strong>th</strong>e <strong>th</strong>ird <strong>of</strong> <strong>th</strong>e four volumes <strong>of</strong> documents which have resulted<br />
from <strong>th</strong>is inter<strong>ac</strong>tive research work between AIT and <strong>th</strong>e NRIs.<br />
This volume on “<strong>Technology</strong>, energy efficiency and environmental externalities in <strong>th</strong>e pulp<br />
and paper industry” covers a description <strong>of</strong> <strong>th</strong>e paper manuf<strong>ac</strong>turing process, and <strong>th</strong>e<br />
energy and environmental aspects associated wi<strong>th</strong> it. Then <strong>th</strong>ere is a cross-country<br />
comparison <strong>of</strong> <strong>th</strong>e pulp and paper sector in <strong>th</strong>e four countries, followed by individual<br />
country reports prepared by <strong>th</strong>e four NRIs. The first five chapters were prepared by Dr. B.<br />
Mohanty and Dr. Uwe Stoll wi<strong>th</strong> <strong>th</strong>e assistance <strong>of</strong> research associates figuring in <strong>th</strong>e Project<br />
Team.<br />
Sincere <strong>th</strong>anks are extended to all <strong>th</strong>e members <strong>of</strong> <strong>th</strong>e Project Team including <strong>th</strong>e<br />
supporting staff, past and present, for <strong>th</strong>eir <strong>ac</strong>tive participation and contribution to <strong>th</strong>e<br />
project. The en<strong>th</strong>usiasm and dynamism <strong>of</strong> Dr. X. Chen during <strong>th</strong>e execution <strong>of</strong> <strong>th</strong>e first<br />
phase and <strong>th</strong>e understanding and leadership provided by Dr. C. Visvana<strong>th</strong>an in <strong>th</strong>e crucial<br />
completion period <strong>of</strong> <strong>th</strong>e project are <strong>ac</strong>knowledged here. The project would have never<br />
seen <strong>th</strong>e light <strong>of</strong> <strong>th</strong>e day wi<strong>th</strong>out <strong>th</strong>e support <strong>of</strong> Sida. Finally, appreciations are due to two<br />
individuals who have <strong>ac</strong>tually conceived <strong>th</strong>e <strong>Asian</strong> Regional Research Programme on<br />
Energy, Environment and Climate (ARRPEEC) and provided constant support and<br />
encouragement to <strong>th</strong>is specific project under <strong>th</strong>e overall program: Dr. M.R. Bhagawan,<br />
Senior Research Adviser at Sida, and Dr. S.C. Bhatt<strong>ac</strong>harya, Pr<strong>of</strong>essor at AIT.<br />
Brahmanand Mohanty<br />
<strong>Asian</strong> <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong><br />
June, 1997
PROJECT TEAM<br />
F<strong>ac</strong>ulty Members (<strong>Asian</strong> <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong> - School <strong>of</strong> Environment,<br />
Resources and Development)<br />
- Dr. Xavier Chen, Energy Program (Until February 1996)<br />
- Dr. Brahmanand Mohanty, Energy Program<br />
- Dr. Uwe Stoll, Environmental Engineering Program (Until January 1996)<br />
- Dr. C. Visvana<strong>th</strong>an, Environmental Engineering Program (From January 1996)<br />
Research Associates (<strong>Asian</strong> <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong> - School <strong>of</strong> Environment,<br />
Resources and Development)<br />
- Ms. Nahid Amin<br />
- Ms. Lilita B. B<strong>ac</strong>areza<br />
- Mr. Z. Khandkar<br />
- Mr. Aung Naing Oo<br />
- Mr. K. Parameshwaran<br />
National Research <strong>Institute</strong>s<br />
- <strong>Institute</strong> for Techno-Economics and Energy System Analysis, Tsinghua<br />
University, Beijing, China (Pr<strong>of</strong>. Qiu Daxiong)<br />
- Energy Management Centre, Ministry <strong>of</strong> Power, New Delhi, India (Mr. S.<br />
Ramaswamy)<br />
- Department <strong>of</strong> Energy, Manila, Philippines (Mr. C.T. Tupas)<br />
- Energy Conservation Fund, Ministry <strong>of</strong> Irrigation, Power and Energy, Colombo,<br />
Sri Lanka (Mr. U. Daranagama)<br />
Research Fellows<br />
- Dr. Wu Xiaobo, School <strong>of</strong> Management, Zhejiang University, China (January-<br />
June 1996)<br />
- Ms. Wang Yanjia, Tsinghua University, China (May-November 1996)<br />
- Mr. Anil Kumar Aneja, Thapar Corporate R&D Centre, India (May-November<br />
1996)<br />
- Ms. Marisol Portal, National Power Corporation, Philippines (May-November<br />
1996)<br />
- Mr. Gamini Senanayake, Industrial Services Bureau <strong>of</strong> Nor<strong>th</strong> Western Province,<br />
Sri Lanka (May-November 1996)
CONTENTS<br />
FOREWARD<br />
PREFACE<br />
PROJECT TEAM<br />
1. GENERAL........................................................................................................................................ 1<br />
2. PRODUCTION PROCESSES ......................................................................................................... 2<br />
2.1 PULPING PROCESSES .................................................................................................................................................2<br />
2.1.1 Sulfite pulping process .............................................................................................................................................4<br />
2.1.2 Kraft (sulfate) pulping process..................................................................................................................................4<br />
2.1.3 Semi-chemical pulping process..................................................................................................................................5<br />
2.1.4 Mechanical pulping process......................................................................................................................................6<br />
2.2 CHEMICAL PROCESSING LINE ..................................................................................................................................6<br />
2.3 FIBER PROCESSING LINE ...........................................................................................................................................9<br />
2.4 BLEACHING OF PULP .................................................................................................................................................9<br />
2.5 CHEMICAL PLANT ................................................................................................................................................... 11<br />
2.6 MANUFACTURING PROCESS OF PAPER ............................................................................................................... 11<br />
3. ENERGY ISSUES IN PULP AND PAPER INDUSTRY...............................................................13<br />
3.1 TYPICAL ENERGY CONSUMPTION PATTERNS ................................................................................................... 13<br />
3.2 ENERGY EFFICIENT MEASURES........................................................................................................................... 15<br />
3.2.1 Short term measures............................................................................................................................................. 15<br />
3.2.2 Medium term measures......................................................................................................................................... 15<br />
3.2.3 Long term measures ............................................................................................................................................. 17<br />
3.3 NEW ENERGY EFFICIENT TECHNOLOGIES FOR PAPERMAKING .................................................................. 19<br />
3.4 CONCLUDING REMARKS ON ENERGY ISSUES ................................................................................................... 20<br />
4. SOURCES OF POLLUTION AND ITS MANAGEMENT.......................................................... 22<br />
4.1 SOURCES AND CHARACTERISTICS OF POLLUTANTS ......................................................................................... 22<br />
4.1.1 Sources <strong>of</strong> wastewater generated ............................................................................................................................ 22<br />
4.1.2 Char<strong>ac</strong>teristics <strong>of</strong> wastewater generated ................................................................................................................. 23<br />
4.1.3 Sources and char<strong>ac</strong>teristics <strong>of</strong> gaseous emissions..................................................................................................... 25<br />
4.1.4 Sources and char<strong>ac</strong>teristics <strong>of</strong> solid wastes ............................................................................................................. 25<br />
4.2 CURRENT POLLUTION ABATEMENT STRATEGIES AND TECHNOLOGIES..................................................... 25<br />
4.2.1 Water pollution control......................................................................................................................................... 25<br />
4.2.2 Solid waste disposal.............................................................................................................................................. 29<br />
4.3 POSSIBILITIES FOR APPLICATION OF ALTERNATIVE TECHNOLOGIES FOR POLLUTION CONTROL ....... 29<br />
4.3.1 Anaerobic treatment <strong>of</strong> wastes .............................................................................................................................. 29<br />
4.3.2 Membrane technology ........................................................................................................................................... 29<br />
4.3.3 Dissolved air floatation for fiber recovery............................................................................................................... 30<br />
4.3.4 Ozone ble<strong>ac</strong>hing ................................................................................................................................................... 30<br />
4.3.5 Modified continuous cooking process (MCC)........................................................................................................ 31<br />
4.3.6 DARS in soda pulping <strong>of</strong> bagasse ....................................................................................................................... 32<br />
4.3.7 Dry forming <strong>of</strong> paper web..................................................................................................................................... 32
4.4 CONCLUDING REMARKS ON POLLUTION MANAGEMENT...................................................................................<br />
5. CROSS COUNTRY REPORT ON THE PULP AND PAPER INDUSTRY................................ 34<br />
5.1 INTRODUCTION ....................................................................................................................................................... 34<br />
5.2 OVERVIEW OF THE INDUSTRY.............................................................................................................................. 34<br />
5.2.1 Role in <strong>th</strong>e national economy ................................................................................................................................ 34<br />
5.2.2 Share in total energy consumption......................................................................................................................... 34<br />
5.2.3 Production trends ................................................................................................................................................. 35<br />
5.2.4 Mills and <strong>th</strong>eir cap<strong>ac</strong>ities...................................................................................................................................... 36<br />
5.3 CHARACTERISTICS OF THE PARAMETERS AFFECTING ENERGY EFFICIENCY ............................................. 38<br />
5.3.1 Raw material mix................................................................................................................................................ 39<br />
5.3.2 Level <strong>of</strong> waste paper utilization ............................................................................................................................ 39<br />
5.3.3 Energy consumption by type.................................................................................................................................. 39<br />
5.3.4 Awareness about energy conservation .................................................................................................................... 40<br />
5.4 CHARACTERISTICS OF THE PARAMETERS AFFECTING POLLUTION ABATEMENT MEASURES..................... 41<br />
5.4.1 Causes <strong>of</strong> pollution............................................................................................................................................... 42<br />
5.4.2 Current water pollution control strategies .............................................................................................................. 42<br />
5.4.3 Current air pollution control strategies .................................................................................................................. 44<br />
5.4.4 Current solid waste control strategies..................................................................................................................... 44<br />
5.4.5 Comparison <strong>of</strong> effluent and emission char<strong>ac</strong>teristics............................................................................................... 44<br />
5.5 POTENTIAL FOR ENERGY EFFICIENCY IMPROVEMENT .................................................................................. 46<br />
5.5.1 Structure <strong>of</strong> <strong>th</strong>e industry ....................................................................................................................................... 46<br />
5.5.2 Raw materials...................................................................................................................................................... 46<br />
5.5.3 Potential for energy conservation............................................................................................................................ 46<br />
5.6 POTENTIAL FOR POLLUTION ABATEMENT......................................................................................................... 46<br />
5.7 CONCLUSION............................................................................................................................................................ 49<br />
6. PROFILE OF THE PULP AND PAPER INDUSTRY IN SELECTED ASIAN<br />
COUNTRIES…………………………………………………………………………………………….50<br />
6.1 COUNTRY REPORT: CHINA.................................................................................................................................... 50<br />
6.1.1 Introduction.......................................................................................................................................................... 50<br />
6.1.2 Technological trajectory <strong>of</strong> China’s paper industry................................................................................................. 54<br />
6.1.3 Evolution <strong>of</strong> energy efficiency in Chinese pulp & paper industry ........................................................................... 61<br />
6.1.4 Environmental externalities <strong>of</strong> <strong>th</strong>e pulp & paper industry in China..................................................................... 67<br />
6.1.5 Potential for energy efficiency improvement and pollution abatement <strong>th</strong>rough technological changes.......................... 70<br />
6.1.6 Status <strong>of</strong> application <strong>of</strong> new technologies................................................................................................................ 75<br />
6.1.7 Conclusions.......................................................................................................................................................... 77<br />
6.2 COUNTRY REPORT: INDIA............................................................................................................................ 79<br />
6.2.1 Introduction.......................................................................................................................................................... 79<br />
6.2.2 Technological trajectory <strong>of</strong> <strong>th</strong>e Indian paper industry ............................................................................................. 79<br />
6.2.3 Evolution <strong>of</strong> energy efficiency in Indian pulp and paper industry ........................................................................... 87<br />
6.2.4 Environmental externalities <strong>of</strong> technological development in <strong>th</strong>e pulp and paper industry....................................... 89<br />
6.2.5 Potential for energy efficiency improvement and pollution abatement <strong>th</strong>rough technological change........................... 93<br />
6.2.6 Status <strong>of</strong> <strong>th</strong>e application <strong>of</strong> new technologies.......................................................................................................... 99<br />
6.3 COUNTRY REPORT: PHILIPPINES............................................................................................................ 100<br />
6.3.1 Introduction........................................................................................................................................................ 100<br />
6.3.2 Technological trajectory <strong>of</strong> <strong>th</strong>e paper industry in <strong>th</strong>e Philippines........................................................................... 100<br />
6.3.3 Evolution <strong>of</strong> energy efficiency in <strong>th</strong>e pulp and paper industry <strong>of</strong> <strong>th</strong>e Philippines.................................................... 106
6.3.4 Environmental externalities <strong>of</strong> <strong>th</strong>e pulp and paper industry <strong>of</strong> <strong>th</strong>e Philippines..................................................... 109<br />
6.3.5 Potential for energy efficiency improvement and pollution abatement <strong>th</strong>rough technological changes........................ 111<br />
6.3.6 Status <strong>of</strong> application <strong>of</strong> new technologies.............................................................................................................. 113<br />
6.3.7 Concluding remarks ........................................................................................................................................... 114<br />
6.4 COUNTRY REPORT: SRI LANKA................................................................................................................ 115<br />
6.4.1 Introduction........................................................................................................................................................ 115<br />
6.4.2 Technological trajectory <strong>of</strong> <strong>th</strong>e Sri Lankan pulp and paper industry.................................................................... 115<br />
6.4.3 Evolution <strong>of</strong> energy efficiency in <strong>th</strong>e pulp and paper industry <strong>of</strong> Sri Lanka ......................................................... 117<br />
6.4.4 Environmental externalities in <strong>th</strong>e pulp and paper industry <strong>of</strong> Sri Lanka.......................................................... 117<br />
6.4.5 Potential for energy efficiency improvement and pollution abatement <strong>th</strong>rough technological changes........................ 118<br />
7. BIBLIOGRAPHY ..........................................................................................................................120
General 1<br />
1. GENERAL<br />
Wi<strong>th</strong> paper being an essential commodity <strong>of</strong> today’s society, <strong>th</strong>e pulp and paper industry<br />
has been growing rapidly all over <strong>th</strong>e world. The industry rates among <strong>th</strong>e highest energy<br />
consumers in many countries. Theoretically, <strong>th</strong>e pulp and paper industry should not<br />
require any purchased energy, because waste materials generated can be re-used as fuels.<br />
However, most pulp and paper mills normally purchase 20-50% <strong>of</strong> <strong>th</strong>eir total energy,<br />
mostly as electricity. Al<strong>th</strong>ough <strong>th</strong>e specific energy consumption values <strong>of</strong> paper products<br />
have been decreasing steadily, <strong>th</strong>ere is still potential for energy saving by employing<br />
advanced technologies and by modifying <strong>th</strong>e current energy use pr<strong>ac</strong>tices. One <strong>of</strong> <strong>th</strong>e<br />
distinguishing char<strong>ac</strong>teristics <strong>of</strong> <strong>th</strong>e pulp and paper industry is <strong>th</strong>e enormous generation <strong>of</strong><br />
wastes. Therefore, an integrated appro<strong>ac</strong>h towards energy and environment could be highly<br />
beneficial for <strong>th</strong>e future betterment <strong>of</strong> <strong>th</strong>e industry.<br />
Environmental pollution caused by industries is closely related to <strong>th</strong>e technologies used and<br />
to <strong>th</strong>e pattern <strong>of</strong> energy consumption by <strong>th</strong>e technologies. The key to <strong>th</strong>e success <strong>of</strong><br />
pollution abatement in industrial sector will depend on <strong>th</strong>e appro<strong>ac</strong>h <strong>of</strong> regulations,<br />
promotion <strong>of</strong> new technologies in <strong>th</strong>e production and waste minimization <strong>ac</strong>tivities (clean<br />
technologies), and improvement <strong>of</strong> industrial energy efficiency. Energy efficiency<br />
improvement and environmental pollution reduction can only be <strong>ac</strong>hieved by ei<strong>th</strong>er retr<strong>of</strong>it<br />
measures (modification <strong>of</strong> <strong>th</strong>e existing technology and equipment) or by installation <strong>of</strong><br />
clean technologies, or bo<strong>th</strong>.<br />
This document describes <strong>th</strong>e production processes and technologies in use (Sec. 2), <strong>th</strong>e<br />
energy saving opportunities and potential in light <strong>of</strong> bo<strong>th</strong> <strong>th</strong>e existing and new technologies<br />
(Sec. 3), as well as <strong>th</strong>e issues <strong>of</strong> sources <strong>of</strong> pollution and pollution abatement measures<br />
including <strong>th</strong>e possibilities for pollution abatement in <strong>th</strong>e pulp and paper industry in future<br />
(Sec. 4). It also provides a cross country comparison <strong>of</strong> <strong>th</strong>e sector (Sec. 5) followed by<br />
individual country reports on <strong>th</strong>e pulp and paper industry <strong>of</strong> four <strong>Asian</strong> industrializing<br />
nations (Sec. 6).
2 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
2. PRODUCTION PROCESSES<br />
Raw materials primarily considered for commercial scale production <strong>of</strong> pulp and paper<br />
include pine, bamboo, rubber wood, mixed tropical hardwood, bagasse, Burma grass and<br />
rice straw. These raw materials consist mainly <strong>of</strong> cellulose, hemicellulose and lignin.<br />
Cellulose and hemicellulose are polys<strong>ac</strong>charides as starch. Target <strong>of</strong> <strong>th</strong>e pulping process is<br />
to cr<strong>ac</strong>k and remove <strong>th</strong>is matrix and separate out <strong>th</strong>e pure cellulose as a natural and<br />
resistant raw product. Lignin, hemicellulose and <strong>th</strong>e extr<strong>ac</strong>ts are separated by cooking in a<br />
digester. Lignin becomes dissolved by sulfonization, hemicellulose gets hydrolyzed and <strong>th</strong>e<br />
extr<strong>ac</strong>ts get partly dissolved under <strong>ac</strong>idic conditions. In <strong>th</strong>e ensuing procedural steps<br />
(ble<strong>ac</strong>hing process), <strong>th</strong>e remaining lignin gets oxidized, bo<strong>th</strong> in <strong>ac</strong>idic and alkaline phase,<br />
whereas <strong>th</strong>e hemicellulose and extr<strong>ac</strong>ts get dissolved mainly in <strong>th</strong>e alkaline phase.<br />
Only about 40% <strong>of</strong> <strong>th</strong>e raw material input is represented in <strong>th</strong>e solid yield. The<br />
environmental problem wi<strong>th</strong> <strong>th</strong>e pulp and paper industry is evidently <strong>th</strong>e o<strong>th</strong>er 60%, which<br />
is <strong>th</strong>e liquid by-product and has to be treated fur<strong>th</strong>er. General flowchart <strong>of</strong> <strong>th</strong>e pulp and<br />
paper making process is given in Figure 2.1. The pulp may be broadly classified as follows:<br />
- High quality pulp<br />
- Sulfite pulp (SP)<br />
- Kraft / Sulfate pulp (KP)<br />
- Low quality pulp (wood fibric)<br />
- Semichemical pulp (SCP)<br />
- Ground or Mechanical pulp (GP)<br />
2.1 Pulping Processes<br />
The main manuf<strong>ac</strong>turing processes <strong>of</strong> pulp production are:<br />
- Sulfite Pulping (SP): chemical pulping, <strong>ac</strong>idic process, cooks <strong>th</strong>e chips wi<strong>th</strong> <strong>ac</strong>id<br />
sulfite solution at a high temperature for half a day.<br />
- Kraft or Sulfate Pulping (KP): chemical pulping, alkaline process, cooks <strong>th</strong>e chips<br />
wi<strong>th</strong> caustic soda and sodium sulfate at a high temperature (160°C) for several<br />
hours. Ble<strong>ac</strong>hed Kraft pulp can be processed into papers <strong>of</strong> high grade.<br />
- Semichemical Pulping (SCP): combination <strong>of</strong> chemical and mechanical pulping processes.<br />
- Ground or Mechanical Pulping (GP): involves mechanical grinding <strong>of</strong> wood,<br />
generates less pollution. However, <strong>th</strong>is process is not suitable for products wi<strong>th</strong><br />
quality requirements, because <strong>of</strong> less durability and poor color.
Production Processes 3<br />
RAW MATERIAL<br />
PREPARATION<br />
PULPING<br />
Χ Chemical Pulping<br />
Alkaline<br />
- Kraft or sulfate√<br />
- Soda pulping<br />
Acidic or sulfite<br />
Χ Mechanical<br />
- GWP - RMP<br />
- TMP - CTMP<br />
Χ Semi-chemical Pulping<br />
- Neutral sulfite<br />
BLEACHING<br />
PAPER MAKING<br />
Process Flow (including<br />
Raw Materials & By-Products)<br />
Steam / Hot water<br />
Chemicals<br />
- Alkaline sulfate liquor (Kraft)<br />
- Acid sulfite liquor (Acidic)<br />
- Neutral sulfite liquor<br />
(Semi-chemical)<br />
White water<br />
(Reuse water),<br />
or Fresh water<br />
Ble<strong>ac</strong>hing<br />
Chemicals<br />
White water or<br />
Fresh water<br />
Fillers, Dye,<br />
Alum, Starch<br />
White water or<br />
Fresh water<br />
Fresh water or<br />
White water<br />
Steam<br />
Coating<br />
Chemicals<br />
Raw Materials<br />
(Conventional: Wood<br />
O<strong>th</strong>ers: Grass, Bagasse,<br />
Straw etc.)<br />
Chipper<br />
Debarked Wood / Woodchips<br />
Pulp Digester<br />
Crude Pulp<br />
Screening &<br />
Washing<br />
Fine Purified Pulp<br />
Chemical reuse<br />
Chemical<br />
recovery boiler<br />
Thickening<br />
Unble<strong>ac</strong>hed Pulp<br />
Ble<strong>ac</strong>hing Plant<br />
Ble<strong>ac</strong>hed pulp<br />
Stock<br />
Preparation<br />
Paper M<strong>ac</strong>hine<br />
Drying &<br />
Finishing<br />
Finished Paper<br />
Products<br />
Wood wastes, barks etc.<br />
to Waste Boiler<br />
Weak bl<strong>ac</strong>k liquor<br />
Evaporator<br />
Sedimentation &<br />
Aerobic treatment<br />
Waste paper<br />
(secondary intake)<br />
Refining<br />
to Treatment plants<br />
Strong bl<strong>ac</strong>k liquor to Combustion<br />
Condensate<br />
to Anaerobic<br />
treatment<br />
Electricity<br />
Steam<br />
(180°C,<br />
12-13 GJ/t)<br />
Electricity<br />
220-300 kWh/t<br />
400-520 kWh/t<br />
Steam<br />
(5 GJ/t)<br />
Electricity<br />
Electricity<br />
Steam<br />
(5-6 GJ/t)<br />
Steam<br />
(8 GJ/t)<br />
Electricity<br />
Energy Flow<br />
Raw Materials<br />
(Conventional: Wood<br />
O<strong>th</strong>ers: Grass, Bagasse,<br />
Straw etc.)<br />
Debarked Wood / Woodchips<br />
Pulp Digester<br />
Crude Pulp<br />
Screening &<br />
Washing<br />
Fine Purified Pulp<br />
Thickening<br />
Unble<strong>ac</strong>hed Pulp<br />
Ble<strong>ac</strong>hed pulp<br />
Stock<br />
Preparation<br />
Paper M<strong>ac</strong>hine<br />
Drying &<br />
Finishing<br />
Finished Paper<br />
Products<br />
Figure 2.1. Process flow chart <strong>of</strong> <strong>th</strong>e pulp and paper industry<br />
Chipper<br />
Ble<strong>ac</strong>hing<br />
Waste paper<br />
(secondary intake)<br />
Refining<br />
to pulp digester<br />
Effluents & Emissions<br />
Raw Materials<br />
(Conventional: Wood<br />
O<strong>th</strong>ers: Grass, Bagasse,<br />
Straw etc.)<br />
Chipper<br />
Debarked Wood / Woodchips<br />
Pulp Digester<br />
Crude Pulp<br />
Screening &<br />
Washing<br />
Fine Purified Pulp<br />
Chemical reuse<br />
Chemical<br />
recovery boiler<br />
Thickening<br />
Unble<strong>ac</strong>hed Pulp<br />
Ble<strong>ac</strong>hing Plant<br />
Ble<strong>ac</strong>hed pulp<br />
Stock<br />
Preparation<br />
Paper M<strong>ac</strong>hine<br />
Drying &<br />
Finishing<br />
Finished Paper<br />
Products<br />
Weak bl<strong>ac</strong>k liquor<br />
Evaporator<br />
Sedimentation &<br />
Aerobic treatment<br />
Sludge,<br />
Ble<strong>ac</strong>h water<br />
Waste paper<br />
(secondary intake)<br />
Refining<br />
Heat emission<br />
White water,<br />
Fiber, Fillers,<br />
Broke, etc.<br />
Liquid clean-up,<br />
Broke, Coatings etc.<br />
to Treatment plants<br />
Evaporative emission<br />
Strong bl<strong>ac</strong>k liquor<br />
to Combustion<br />
to Anaerobic<br />
Condensate treatment<br />
Gaseseous emission<br />
Effluent<br />
Fiber & ink<br />
sludge
4 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
It is estimated <strong>th</strong>at <strong>th</strong>e proportion <strong>of</strong> pulp produced in <strong>th</strong>e world using <strong>th</strong>ese major processes<br />
are: 75% chemical pulp (mostly Kraft), 20% mechanical pulp, and <strong>th</strong>e remaining 5% o<strong>th</strong>er<br />
pulps (RAO et al, 1995).<br />
2.1.1 Sulfite pulping process<br />
The fiber binding lignin is s<strong>of</strong>tened and dissolved to a considerable extent in a solution<br />
-<br />
containing dissolved SO2, hydrogensulfite (bisulfite) ion (HSO3 ), or sulfite ions, producing <strong>ac</strong>id<br />
-<br />
sulfite or bisulfite chemical pulps. The HSO3 re<strong>ac</strong>ts in <strong>th</strong>e digester wi<strong>th</strong> <strong>th</strong>e phenolic group on<br />
<strong>th</strong>e lignin, forming sulfonic <strong>ac</strong>ids.<br />
The yield varies from 45 to 65% depending on <strong>th</strong>e cooking degree, usually <strong>th</strong>e yield is about<br />
50% for standard non-ble<strong>ac</strong>hed pulps. If <strong>th</strong>e pulp is ble<strong>ac</strong>hed, ano<strong>th</strong>er 4 to 5% <strong>of</strong> <strong>th</strong>e original<br />
wood may be lost in <strong>th</strong>e process. This sulfite me<strong>th</strong>od is one <strong>of</strong> two major wood-pulping<br />
processes. The cellulose fiber obtained from <strong>th</strong>e sulfite process is less strong compared to <strong>th</strong>e<br />
Kraft process.<br />
2.1.2 Kraft (sulfate) pulping process<br />
The soda process has been largely repl<strong>ac</strong>ed by <strong>th</strong>e sulfate or (Kraft) process. This process<br />
includes not only NaOH, but also Na 2S in <strong>th</strong>e cooking liquor. The presence <strong>of</strong> caustic soda in<br />
<strong>th</strong>e cooking liquor makes <strong>th</strong>is pulping process suitable for use wi<strong>th</strong> all wood species. Sodium<br />
sulfate plays a buffering role <strong>th</strong>at allows digestion to be possible at lower pH, <strong>th</strong>us reducing<br />
damage to <strong>th</strong>e fibers and producing pulp wi<strong>th</strong> high streng<strong>th</strong> property. In water solution, <strong>th</strong>e<br />
sulfide ion (S 2- ) hydrolyzes to form hydroxide ions (OH - ) and hydrogen sulfide ions (HS - )<br />
<strong>ac</strong>cording to <strong>th</strong>e formula :<br />
S 2-- + H 2 O → HS - + OH -<br />
The initial high concentration <strong>of</strong> NaOH (hence OH - ions) forces <strong>th</strong>e equilibrium to <strong>th</strong>e left,<br />
<strong>ac</strong>cording to Le Chatelier’s principle. The net result being <strong>th</strong>at delignification occurs at a more<br />
steady rate and HS - can also re<strong>ac</strong>t wi<strong>th</strong> <strong>th</strong>e lignin to enhance its solubility. The residual liquor is<br />
very dark, and is called <strong>th</strong>e “Bl<strong>ac</strong>k liquor”. The flowchart <strong>of</strong> Kraft or sulfate process is shown in<br />
Figure 2.2.<br />
As ano<strong>th</strong>er alkaline pulping process, soda pulping process is used in which <strong>th</strong>e cooking liquor is<br />
sodium hydroxide, obtained by adding a mixture <strong>of</strong> soda ash (Na 2CO 3) and lime [Ca(OH) 2] to<br />
<strong>th</strong>e digester. The digestion phase is in operation for about 10 hours under high pressure and<br />
temperature. The digestion decomposes or separates <strong>th</strong>e binding, non-cellulose materials such<br />
as lignin and resins, from <strong>th</strong>e fibers and consequently, weakens <strong>th</strong>em. This me<strong>th</strong>od is rarely<br />
used at present and has been largely repl<strong>ac</strong>ed by <strong>th</strong>e Kraft pulping process.
Production Processes 5<br />
Wood Chios<br />
Water<br />
Pulp to Ble<strong>ac</strong>h<br />
Plant<br />
Evaporator<br />
Evaporator<br />
Condensates<br />
Digester<br />
Brownst<strong>ac</strong>k<br />
Washers<br />
Weak Bl<strong>ac</strong>k<br />
Liquor<br />
NaOH /<br />
Na 2 S<br />
Na 2 SO 4 +<br />
organics<br />
Strong<br />
Bl<strong>ac</strong>k Liquor<br />
Make-Up Caustic<br />
(NaOH)<br />
2.1.3 Semi-chemical pulping process<br />
White Liquor<br />
Storage<br />
White Liquor<br />
Clarifier<br />
Recovery<br />
Boiler<br />
Slaker and<br />
Caustizers<br />
Green Liquor<br />
Clarifier<br />
Smelt<br />
Lime<br />
Mud<br />
Washer<br />
Make- Up Saltcake ( Na 2 SO 4 )<br />
Na 2 S / Na 2 CO 3<br />
Smelt<br />
Dissolving<br />
Tank<br />
Lime Mud<br />
Thickener<br />
Lime Kiln<br />
Figure 2.2. Kraft (sulfate) pulping process<br />
Weak Wash<br />
Water<br />
Dregs<br />
Washer<br />
In <strong>th</strong>is process, hardwood and s<strong>of</strong>t wood pulp is obtained by a series <strong>of</strong> chemical and<br />
mechanical wood treatments, none <strong>of</strong> which by itself is sufficient to make fibers separate<br />
readily. Unlike chemical pulping, <strong>th</strong>is process enables more <strong>of</strong> <strong>th</strong>e lignin and hemicellulose<br />
constituents <strong>of</strong> wood to be retained in <strong>th</strong>e pulp and <strong>th</strong>us <strong>th</strong>e pulp yield is <strong>of</strong>ten very high (about<br />
75-80%, based on dried wood). The process involves cooking <strong>of</strong> chips (hardwood) for 10-20<br />
minutes at a temperature <strong>of</strong> 175-185 0 C wi<strong>th</strong> an aqueous solution <strong>of</strong> sodium sulfite and sodium<br />
carbonate. The amount <strong>of</strong> pulping chemical required is about 9-19% Na 2CO 3 and 4-7% SO 2 per<br />
ton <strong>of</strong> dried wood. The pulp is defiberized mechanically in disc refiners and washed by a<br />
counter-current me<strong>th</strong>od on rotary drums (Kleppe and Rogers, 1970).<br />
Lime<br />
Stone
6 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
2.1.4 Mechanical pulping process<br />
Mechanical pulp is produced by grinding or shredding raw materials to free fibers. In addition,<br />
heat under pressure may be applied to assist <strong>th</strong>e process. It consists <strong>of</strong> two principal physical<br />
me<strong>th</strong>ods <strong>of</strong> producing ground wood pulp. The older technology involves grinding <strong>th</strong>e logs and<br />
stone grinding on large grind stones, whereas <strong>th</strong>e modern technology employs chip refining or<br />
refined ground-wood. Ble<strong>ac</strong>hing may be done by adding a small amount <strong>of</strong> sodium peroxide<br />
and/or hydrogen sulfite. Mechanical pulping provides low grade pulps wi<strong>th</strong> high color and<br />
relatively short fibers, but produces a high yield, converting about 95% <strong>of</strong> <strong>th</strong>e wood into pulp;<br />
minimal on-site air pollution is produced and relatively low water loads are generated<br />
(Anonymous 1981). The modern mechanical pulping process is illustrated in Figure 2.3.<br />
2.2 Chemical processing line<br />
Recovery <strong>of</strong> pulping chemicals is, in f<strong>ac</strong>t, limited to sodium and magnesium-based liquors, since<br />
calcium cannot be recovered economically and <strong>th</strong>ere is only limited experience on recovery <strong>of</strong><br />
ammonia (Anonymous, 1982). In <strong>th</strong>e chemical processing, high-efficiency recovery <strong>of</strong> chemicals<br />
is <strong>ac</strong>hieved. Maximum recovery <strong>of</strong> <strong>th</strong>e chemicals may result in a relatively cleaner effluent in<br />
which chemical toxicants are no longer a significant f<strong>ac</strong>tor as far as stream pollution is<br />
concerned.<br />
In <strong>th</strong>e sulfite pulping process, magnesium bisulfite is recovered. Dissolved wood substances are<br />
99% in <strong>th</strong>e weak bl<strong>ac</strong>k liquor obtained from cooking after pulp separation. This weak bl<strong>ac</strong>k<br />
liquor has about 13% <strong>of</strong> dry solids (DS). After evaporation, <strong>th</strong>e weak bl<strong>ac</strong>k liquor is converted<br />
to a strong liquor containing about 45% <strong>of</strong> DS. The bl<strong>ac</strong>k liquor from <strong>th</strong>e evaporation plant is<br />
led to <strong>th</strong>e recovery boiler. This liquor is fur<strong>th</strong>er evaporated in a cascade evaporator in <strong>th</strong>e<br />
recovery boiler up to 60% total solids before being burnt in <strong>th</strong>e boiler. Ash from gas cleaning<br />
consists mainly <strong>of</strong> magnesium oxide. It gets hydrolyzed to magnesium hydroxide which, in turn,<br />
is used for flue gas cleaning. Final product is magnesium bisulfite solution to which SO 2 and<br />
MgO are added for its reuse in <strong>th</strong>e cooking process.<br />
The treatment <strong>of</strong> bl<strong>ac</strong>k liquor from Kraft mills involves evaporation and incineration in order to<br />
recover <strong>th</strong>e chemicals and to utilize <strong>th</strong>e heating value <strong>of</strong> <strong>th</strong>e dissolved wood substance. During<br />
<strong>th</strong>e recovery process, Na 2SO 4 (wi<strong>th</strong> or wi<strong>th</strong>out added sulfur) is added to make up <strong>th</strong>e relatively<br />
small proportion <strong>of</strong> chemicals lost in various steps <strong>of</strong> <strong>th</strong>e process, and to form <strong>th</strong>e green liquor.<br />
The chemical compounds in <strong>th</strong>is green liquor are converted to desired cooking chemicals by <strong>th</strong>e<br />
addition <strong>of</strong> lime so as to form <strong>th</strong>e white liquor and a lime-mud consisting chiefly <strong>of</strong> CaCO 3. The<br />
white liquor is returned to <strong>th</strong>e pulping operation as <strong>th</strong>e cooking liquor. Lime mud is calcined to<br />
form CaO which is reused by converting o<strong>th</strong>er green liquor to white liquor. By-product<br />
recovery <strong>of</strong> turpentine, resin and fatty <strong>ac</strong>ids also aids in reducing <strong>th</strong>e streng<strong>th</strong> <strong>of</strong> Kraft pulp<br />
waste water.
Production Processes 7<br />
Sewer<br />
Water<br />
White Water<br />
Tank<br />
Saveall<br />
Wood<br />
Grinder Room<br />
Storage<br />
Grinder<br />
Coarse Screen<br />
Fine Screen<br />
Centrifugal<br />
Cleaners<br />
Deckers<br />
Storage<br />
Ble<strong>ac</strong>hing<br />
Paper M<strong>ac</strong>hine<br />
Paper<br />
2 % Consistency<br />
0.6 - 0.8 % Consistency<br />
Sewer<br />
Figure 2.3. Flow chart <strong>of</strong> <strong>th</strong>e mechanical pulping process<br />
Refiners<br />
Water
8 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Special Issues Related to Chemical Processing Line<br />
A. Chemical recovery <strong>of</strong> bl<strong>ac</strong>k liquor from rice straw pulping<br />
Rice straw contains 8-14 % <strong>of</strong> silica (SiO2). For chemical pulp produced from rice straw, about<br />
half <strong>of</strong> <strong>th</strong>is silica gets dissolved in <strong>th</strong>e bl<strong>ac</strong>k liquor. This causes problems in all stages <strong>of</strong> <strong>th</strong>e<br />
chemical recovery process.<br />
For a pulp mill <strong>th</strong>at depends on non-wood fiber, silica must be eliminated from bl<strong>ac</strong>k liquor to<br />
produce pulp economically and to meet environmental restrictions. The chemical recovery in<br />
<strong>th</strong>is application is relatively new and <strong>th</strong>ere is only limited information and experience today.<br />
Following is an example <strong>of</strong> such a recovery me<strong>th</strong>od:<br />
Investigations on desilication <strong>of</strong> rice straw bl<strong>ac</strong>k liquor started in <strong>th</strong>e 1970s and a pilot plant was<br />
started in 1985 (UNEP IE/PAC, 1992). In <strong>th</strong>e proposed chemicals recovery and desilication<br />
process, bl<strong>ac</strong>k liquor coming from <strong>th</strong>e washing unit is filtered in a drum-filter. The out-flowing<br />
bl<strong>ac</strong>k liquor is fed <strong>th</strong>rough a buffering tank to <strong>th</strong>e four-effect evaporator plant. For low<br />
concentrations, evaporation takes pl<strong>ac</strong>e in <strong>th</strong>ree long-tube falling film evaporators. Higher<br />
concentrations are attained in a forced circulation evaporator, which pre-concentrates <strong>th</strong>e bl<strong>ac</strong>k<br />
liquor to a DS content <strong>of</strong> between 8 and 14% - <strong>th</strong>e optimum for effective desilication. The<br />
forced-circulation stage fur<strong>th</strong>er concentrates <strong>th</strong>e desilicated bl<strong>ac</strong>k liquor.<br />
Next, a stream <strong>of</strong> pre-concentrated bl<strong>ac</strong>k liquor is fed to a draft-tube re<strong>ac</strong>tor equipped wi<strong>th</strong><br />
stirrer and foam breaker, where it is brought into intimate cont<strong>ac</strong>t wi<strong>th</strong> a continuous stream <strong>of</strong><br />
flue gas from <strong>th</strong>e power station st<strong>ac</strong>k. Here, soluble sodium silicates are converted into sodium<br />
carbonate and largely insoluble SiO 2. This two-phase mixture is routed <strong>th</strong>rough an intermediate<br />
tank to a decanter which separates <strong>th</strong>e precipitates from <strong>th</strong>e clean liquor. For final clarification,<br />
<strong>th</strong>e liquor is passed <strong>th</strong>rough a separator ,where <strong>th</strong>e residual insoluble particles are removed.<br />
Subsequently, <strong>th</strong>is desilicated bl<strong>ac</strong>k liquor is <strong>th</strong>en burned in <strong>th</strong>e conventional way. The optimum<br />
pH value is between 9 and 10. The corresponding specific flue gas rate at a CO 2 concentration<br />
<strong>of</strong> 6-8% is in <strong>th</strong>e range <strong>of</strong> 50 to 150 m 3 gas (at NTP) per m 3 <strong>of</strong> bl<strong>ac</strong>k liquor. Irrespective <strong>of</strong> <strong>th</strong>e<br />
silica content <strong>of</strong> <strong>th</strong>e incoming bl<strong>ac</strong>k liquor, which typically is <strong>of</strong> <strong>th</strong>e order <strong>of</strong> 1% (by weight),<br />
total silica contents <strong>of</strong> 0.05% by weight were attained downstream <strong>of</strong> <strong>th</strong>e separator. The silica<br />
extr<strong>ac</strong>ted from <strong>th</strong>e bl<strong>ac</strong>k liquor, toge<strong>th</strong>er wi<strong>th</strong> some alkali and organic matter, forms a sludge<br />
which is discharged from <strong>th</strong>e decanter at a DS content <strong>of</strong> 30-40%, and burnt in a fuel-oil-fired<br />
incinerator. Elution <strong>of</strong> <strong>th</strong>e alkali from <strong>th</strong>e ash wi<strong>th</strong> water, followed by filtering and drying, yields<br />
almost white silica granulates, which can be used as a filler in paper making.
Production Processes 9<br />
B. Use <strong>of</strong> bl<strong>ac</strong>k liquor as fertilizers<br />
Potassium fertilizer<br />
A potassium alkaline sulfite process can be used to produce <strong>th</strong>e chemical pulp. The pulping<br />
bl<strong>ac</strong>k liquor as well as ble<strong>ac</strong>hing effluent <strong>of</strong> alkaline or neutral sulfite may be collected and<br />
evaporated to obtain a salable liquid fertilizer product, (UNEP IE/PAC, 1992). Solid<br />
organo-potassium fertilizer can also be prepared (ANONYMOUS , 1982).<br />
Ammonia fertilizer<br />
Ano<strong>th</strong>er new process <strong>of</strong> ammonium bisulfite straw pulp has been popularized in many small<br />
size paper mills. By <strong>th</strong>is process, its wastewater can be directly used for farm irrigation as<br />
ammonia fertilizer (WANG YANJIA, 1995).<br />
2.3 Fiber processing line<br />
The fiber processing line employs washing <strong>of</strong> <strong>th</strong>e fibers and separation <strong>of</strong> contaminants from<br />
<strong>th</strong>e raw fibers in a cascaded counter-current process to produce <strong>th</strong>e concentrated pulp. The<br />
remaining liquid is called <strong>th</strong>e weak bl<strong>ac</strong>k liquor.<br />
2.4 Ble<strong>ac</strong>hing <strong>of</strong> pulp<br />
Chemical pulping, especially <strong>th</strong>e Kraft process, produces dark colored pulp owing to a number<br />
<strong>of</strong> f<strong>ac</strong>tors, among which are: remaining lignin, wood components which make paper turn yellow<br />
and brittle, and resinous bark as well as knot particles which leave tiny dark spots on <strong>th</strong>e paper.<br />
In order to obtain white and strong paper, <strong>th</strong>ese constituents should be removed fur<strong>th</strong>er by<br />
ble<strong>ac</strong>hing operations. Ble<strong>ac</strong>hing is a successive process involving multiple steps (normally 4-6)<br />
consisting <strong>of</strong> several oxidation stages (one or two alkaline). It utilizes various chemical agents,<br />
such as chlorine, sodium hydroxide, sodium hypochlorite and chlorine dioxide. Sulfite pulp<br />
needs less ble<strong>ac</strong>hing agents <strong>th</strong>an sulfate pulp.<br />
According to S DERGREN (1993), <strong>th</strong>ere are two types <strong>of</strong> ble<strong>ac</strong>hing sequences: conventional<br />
and modern ble<strong>ac</strong>hing processes (Figure 2.4). The conventional ble<strong>ac</strong>hing technique consists <strong>of</strong><br />
six stages in which chlorine gas is <strong>th</strong>e dominating delignifying agent whereas chlorine dioxide is<br />
used only in <strong>th</strong>e final ble<strong>ac</strong>hing stage. The amount <strong>of</strong> chlorine in <strong>th</strong>e first ble<strong>ac</strong>hing stage is<br />
about 50 to 70 kg per ton <strong>of</strong> pulp. The modern ble<strong>ac</strong>hing technique has been developed since<br />
<strong>th</strong>e mid 1970’s in Sweden. It aims to avoid <strong>th</strong>e discharge <strong>of</strong> chlorinated organic matter from <strong>th</strong>e<br />
ble<strong>ac</strong>hing plant. In modern ble<strong>ac</strong>hing technology, oxygen delignification is used; <strong>th</strong>e charge <strong>of</strong><br />
chlorine in <strong>th</strong>e first ble<strong>ac</strong>hing stage has gradually been reduced by <strong>th</strong>e introduction <strong>of</strong> low<br />
multiple chlorination and by a gradual substitution <strong>of</strong> chlorine by chlorine dioxide to totally<br />
eliminate <strong>th</strong>e use <strong>of</strong> elemental chlorine as <strong>th</strong>e ble<strong>ac</strong>hing agent.
10 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Figure 2.4 Scheme <strong>of</strong> conventional and modern ble<strong>ac</strong>hing sequence
Production Processes 11<br />
2.5 Chemical Plant<br />
Many pulp and paper mills have <strong>th</strong>eir own chemical plants where caustic soda and chlorine are<br />
produced <strong>th</strong>rough electrolysis in diaphragm cells, and calcium hypochlorite is produced from<br />
lime, H 2O, and Cl 2.<br />
2.6 Manuf<strong>ac</strong>turing Process <strong>of</strong> Paper<br />
In <strong>th</strong>is process <strong>th</strong>e pulp is converted into paper. The first stage <strong>of</strong> paper making operation is <strong>th</strong>e<br />
stock preparation. The fibers to be included in <strong>th</strong>e stock are heated and mixed. Different<br />
chemicals and fillers such as aluminum sulfate, clay and starch are also added to <strong>th</strong>e pulp stock<br />
for enhancement <strong>of</strong> certain properties <strong>of</strong> <strong>th</strong>e paper or board. The stock is <strong>th</strong>en pumped to <strong>th</strong>e<br />
paper m<strong>ac</strong>hine system where it is screened and finally brought to <strong>th</strong>e paper-forming m<strong>ac</strong>hine<br />
itself. In <strong>th</strong>e paper m<strong>ac</strong>hine, <strong>th</strong>e pulp sheet is dewatered on a fine mesh wire, pressed in several<br />
roll presses and air-dried in a semi-heated pulp dryer section. The paper making process is<br />
illustrated in Figure 2.5.<br />
Figure 2.5 Overall paper making process
12 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Recovery processes in <strong>th</strong>e paper mill attempt to recover <strong>th</strong>e washed out fibers and fillers. These<br />
processes are based on sedimentation and floatation principles. Conical or o<strong>th</strong>er sedimentation<br />
tanks are used to separate <strong>th</strong>e suspended solid. Floatation devices are revolving, cylindrical,<br />
perforated screens or filters to remove <strong>th</strong>e suspended solid in <strong>th</strong>e form <strong>of</strong> a mat which is<br />
subsequently scraped <strong>of</strong>f <strong>th</strong>e drum and returned to <strong>th</strong>e paper making stock system.<br />
The use <strong>of</strong> wastepaper as a raw material for paper production is being emphasized nowadays.<br />
This process requires <strong>th</strong>e de-inking <strong>of</strong> <strong>th</strong>e waste paper. The de-inking process has two main<br />
steps (<strong>th</strong>e flotation process and <strong>th</strong>e washing process) and employs various equipment, like pulp<br />
shredder, drum screen, high density cleaner, floatater (closed injection floatater, Sweetmark<br />
floatater, and Lamort floatater), pressurized screen and washer.<br />
When waste newsprint paper is stored for a short period, <strong>th</strong>e ink carrier on <strong>th</strong>e wastepaper is<br />
not sufficiently dried. However, it is absorbed by <strong>th</strong>e fiber only. Under <strong>th</strong>e <strong>ac</strong>tion <strong>of</strong> chemical<br />
reagents and under conditions <strong>of</strong> suitable temperature and consistency, <strong>th</strong>e carrier is saponified.<br />
The ink is dispersed easily and <strong>th</strong>e pigment is also released easily. The pigment, which consists<br />
<strong>of</strong> carbon bl<strong>ac</strong>k, usually forms good particles under <strong>th</strong>e treatment <strong>of</strong> pulp shredder. If waste<br />
paper has been stored for a long time, <strong>th</strong>e ink carriers are solidified due to drying and aging. In<br />
<strong>th</strong>is case, an increased quantity and density <strong>of</strong> de-inking chemical (such as NaOH) must be<br />
added and re<strong>ac</strong>tion temperature and re<strong>ac</strong>tion time should be increased so <strong>th</strong>at <strong>th</strong>e ink can be<br />
saponified. Shredding <strong>of</strong> <strong>th</strong>e wastepaper and putting it in <strong>th</strong>e de-inking chemical are done in<br />
high density pulp shredder, in which <strong>th</strong>e waste newsprint paper is soaked, osmosed, absorbed<br />
and expanded by <strong>th</strong>e solution <strong>of</strong> de-inking chemicals. The main chemicals used in de-inking<br />
process are NaOH and formic <strong>ac</strong>id (HCOOH).
Energy Issues in <strong>th</strong>e Pulp and Paper Industry 13<br />
3. ENERGY ISSUES IN PULP AND PAPER INDUSTRY<br />
3.1 Typical Energy Consumption Patterns<br />
The primary energy sources used in <strong>th</strong>e pulp and paper industry are <strong>th</strong>ermal energy in <strong>th</strong>e<br />
form <strong>of</strong> steam and mechanical energy converted from electricity. The <strong>th</strong>ermal energy<br />
<strong>ac</strong>counts for about 70-80% <strong>of</strong> <strong>th</strong>e total primary energy and is mainly used in pulping and<br />
drying processes. The process steam is generated from waste raw materials, concentrated<br />
bl<strong>ac</strong>k liquor and o<strong>th</strong>er fuels such as coal, fuel oil and gas. In <strong>th</strong>e pulp and paper mills, onsite<br />
electricity generation typically ranges from 0-60% <strong>of</strong> <strong>th</strong>e total power consumption.<br />
The energy consumption <strong>of</strong> a pulp and paper mill depends on <strong>th</strong>e raw materials used, type<br />
<strong>of</strong> pulping process and <strong>th</strong>e degree and type <strong>of</strong> final products. The typical specific energy<br />
consumption values <strong>of</strong> different paper-making processes are shown in Figure 3.1.<br />
GJ/ton <strong>of</strong> Paper Products<br />
35<br />
30<br />
25<br />
20<br />
15<br />
10<br />
5<br />
0<br />
Acid Sulfite<br />
4%<br />
25%<br />
17.5%<br />
8.5%<br />
45%<br />
Kraft<br />
4%<br />
24.5%<br />
17%<br />
15.5%<br />
39%<br />
Semi-<br />
Chemical<br />
3.5%<br />
24%<br />
16.5%<br />
10.5%<br />
45.5%<br />
Groundwood<br />
3.5%<br />
25.5%<br />
17.5%<br />
3.5%<br />
50%<br />
Pulping Ble<strong>ac</strong>hing Paperforming Drying and finishing O<strong>th</strong>ers<br />
Thermomechanical<br />
Figure 3.1 Typical energy consumption <strong>of</strong> paper-making processes<br />
26.5%<br />
From Figure 3.1, it can be seen <strong>th</strong>at <strong>th</strong>e highest energy consumer in a pulp and paper mill is<br />
<strong>th</strong>e pulping process. The average specific energy consumption <strong>of</strong> pulping process is low in<br />
industrialized countries because <strong>of</strong> <strong>th</strong>e higher percentage <strong>of</strong> waste-paper pulp in total pulp<br />
produced. The specific energy consumption <strong>of</strong> waste-paper pulp is about 3 times less <strong>th</strong>an<br />
<strong>th</strong>at <strong>of</strong> wood pulp.<br />
3.5%<br />
18%<br />
4%<br />
48%
14 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
The average specific electricity consumption <strong>of</strong> pulp and paper industry is 1000-1300 kWh<br />
per ton <strong>of</strong> paper products. The percentage <strong>of</strong> total electrical power consumed in different<br />
stages <strong>of</strong> a typical paper manuf<strong>ac</strong>turing process is shown in Figure 3.2.<br />
11%<br />
22%<br />
13%<br />
12%<br />
2%<br />
Paperforming Pulping Chemical plant<br />
Boiler house Water treatment O<strong>th</strong>ers<br />
Figure 3.2 Breakdown <strong>of</strong> electricity consumption in an integrated mill<br />
The temperature level <strong>of</strong> process steam <strong>of</strong> a pulp and paper mill is normally below 200°C.<br />
The typical specific steam requirement is 8-12 tons per ton <strong>of</strong> paper products. The<br />
breakdown <strong>of</strong> process steam is given in Figure 3.3.<br />
5%<br />
21%<br />
33%<br />
Pulping Ble<strong>ac</strong>hing<br />
Hot watermaking Drying<br />
O<strong>th</strong>ers<br />
1%<br />
40%<br />
40%<br />
Figure 3.3 Breakdown <strong>of</strong> process steam in an integrated mill
Energy Issues in <strong>th</strong>e Pulp and Paper Industry 15<br />
3.2 Energy Efficient Measures<br />
As mentioned earlier, <strong>th</strong>e overall energy requirement <strong>of</strong> a pulp and paper mill can be<br />
<strong>th</strong>eoretically met by waste materials and concentrated bl<strong>ac</strong>k liquor. Therefore, <strong>th</strong>e<br />
objectives <strong>of</strong> energy conservation measures in <strong>th</strong>e pulp and paper industry are to reduce <strong>th</strong>e<br />
purchased energy and to recover as much energy from <strong>th</strong>e internal waste fuels as possible.<br />
3.2.1 Short term measures<br />
The immediate <strong>ac</strong>tions which can be taken wi<strong>th</strong>out substantial investment to <strong>ac</strong>hieve a<br />
certain level <strong>of</strong> energy savings in pulp and paper industry are:<br />
- inspection to encourage conservation <strong>ac</strong>tivity<br />
- excess air and flue gas temperature control<br />
- recovery <strong>of</strong> heat from boiler blowdown<br />
- proper insulation <strong>of</strong> steam lines<br />
- power f<strong>ac</strong>tor improvement <strong>of</strong> electric motors<br />
- ensuring an efficient washing (to minimize <strong>th</strong>e dilution <strong>of</strong> bl<strong>ac</strong>k liquor)<br />
- recovery <strong>of</strong> heat from extr<strong>ac</strong>ted bl<strong>ac</strong>k liquor after cooking<br />
- recovery <strong>of</strong> heat from condensate <strong>of</strong> drying process (about 5% <strong>of</strong> fuel can be<br />
saved)<br />
3.2.2 Medium term measures<br />
The medium term measures include modifications in processes and materials, recovery <strong>of</strong><br />
waste heat and self power generation wi<strong>th</strong> moderate to large investments.<br />
3.2.2.1 Measures on processed materials<br />
(i) Higher percentage <strong>of</strong> waste-paper pulp<br />
The recycling <strong>of</strong> more waste paper in pulping can lead to not only energy saving but also<br />
conservation <strong>of</strong> forest and environment. An increase in <strong>th</strong>e percentage <strong>of</strong> waste-paper pulp<br />
by 10% can save about 6.5% <strong>of</strong> energy required for pulping process.<br />
(ii) Recovery <strong>of</strong> chemicals<br />
The amount <strong>of</strong> chemicals recovered in pulping process has an effect on <strong>th</strong>e overall specific<br />
energy consumption <strong>of</strong> <strong>th</strong>e pulp and paper industry. Al<strong>th</strong>ough <strong>th</strong>e chemical recovery rate is<br />
usually high in <strong>th</strong>e larger mills (over 90%), <strong>th</strong>at <strong>of</strong> medium and small mills are low, typically<br />
50-70%. Therefore, proper chemical recovery systems should be installed in <strong>th</strong>e pulp and<br />
paper mills.
16 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
The recovery <strong>of</strong> chemical products by a membrane process, particularly using mineral<br />
membrane <strong>th</strong>rough ultrafiltration, can result in higher recovery rate and less pollution.<br />
Al<strong>th</strong>ough <strong>th</strong>e membrane process consumes electricity required by <strong>th</strong>e pumps to pressurize<br />
<strong>th</strong>e liquid and to circulate it, cogenerated electricity (elaborated later) can support <strong>th</strong>e case<br />
for ultrafiltration.<br />
3.2.2.2 Self energy production<br />
(i) Cogeneration<br />
Cogeneration is a promising technology for better utilization <strong>of</strong> energy sources if process<br />
steam demand is high. Therefore, <strong>th</strong>e pulp and paper industry has a high potential for<br />
application <strong>of</strong> cogeneration. For <strong>th</strong>e high pressure steam systems (60-80 bar), it is possible<br />
to generate excess electricity by as much as 600 kWh per ton <strong>of</strong> paper, which could be sold<br />
to <strong>th</strong>e grid.<br />
The generation <strong>of</strong> surplus electricity is <strong>of</strong> no interest to <strong>th</strong>e industry if <strong>th</strong>e regulation in <strong>th</strong>e<br />
country does not permit <strong>th</strong>e selling <strong>of</strong> <strong>th</strong>is electricity to <strong>th</strong>e grid. As a consequence <strong>of</strong> such<br />
a case, <strong>th</strong>e upper limit is an electrical-match process: <strong>th</strong>e maximum amount <strong>of</strong> electricity<br />
generated is <strong>th</strong>e same as <strong>th</strong>at needed by <strong>th</strong>e f<strong>ac</strong>tory. The pay-b<strong>ac</strong>k period <strong>of</strong> cogeneration<br />
system is around 3-5 years.<br />
(ii) Me<strong>th</strong>anogenesis<br />
The technology <strong>of</strong> me<strong>th</strong>ane generation from organic wastes <strong>th</strong>rough anaerobic digestion<br />
permits at <strong>th</strong>e same time energy recovery and reduction in environmental pollution. The<br />
me<strong>th</strong>anogenesis can compete wi<strong>th</strong> o<strong>th</strong>er waste treatment processes because <strong>of</strong> its potential<br />
for energy production. As an example, <strong>th</strong>e anaerobic digestion process can produce energy<br />
<strong>of</strong> <strong>th</strong>e order <strong>of</strong> 6.4 GJ per ton <strong>of</strong> paper and <strong>th</strong>e pay-b<strong>ac</strong>k period is about 4 years.<br />
3.2.2.3 Modifications in <strong>th</strong>e sub-processes<br />
(i) Conversion <strong>of</strong> batch to continuous digester<br />
Up to 40% <strong>of</strong> steam consumption can be saved by converting <strong>th</strong>e pulping process from<br />
batch to continuous. The continuous pulping can also <strong>of</strong>fer steady recovery <strong>of</strong> heat from<br />
<strong>th</strong>e outgoing materials <strong>of</strong> <strong>th</strong>e digester.<br />
(ii) Mechanical vapor compression<br />
Large amounts <strong>of</strong> energy (in <strong>th</strong>e form <strong>of</strong> steam) are required for concentration <strong>of</strong> bl<strong>ac</strong>k<br />
liquor from 10 to 60% before firing in a heat recovery boiler. This is <strong>ac</strong>hieved<br />
conventionally in a multi-effect evaporator where <strong>th</strong>e vapors from last effect are finally<br />
condensed in a surf<strong>ac</strong>e condenser. Energy <strong>th</strong>us transferred to cooling water cannot<br />
normally be put to useful purpose, especially in <strong>th</strong>e hot tropical climate, due to its lower<br />
heat content.
Energy Issues in <strong>th</strong>e Pulp and Paper Industry 17<br />
The use <strong>of</strong> mechanical vapor recompression (MVR) is suitable for partial concentration (up<br />
to about 23%) <strong>of</strong> bl<strong>ac</strong>k liquor by repl<strong>ac</strong>ing <strong>th</strong>e first stages <strong>of</strong> multi-effect evaporators. The<br />
energy demand <strong>of</strong> bl<strong>ac</strong>k liquor concentration process can be reduced by 70-80% by<br />
pr<strong>ac</strong>tically repl<strong>ac</strong>ing <strong>th</strong>e direct distillation wi<strong>th</strong> MVR. The installation <strong>of</strong> MVR would be<br />
economically more attr<strong>ac</strong>tive wi<strong>th</strong> <strong>th</strong>e availability <strong>of</strong> cogenerated electricity. The pay-b<strong>ac</strong>k<br />
period <strong>of</strong> MVR installation is site specific and varies from 1.5 to 6 years.<br />
(iii) V<strong>ac</strong>uum pump in paperforming<br />
The repl<strong>ac</strong>ement <strong>of</strong> v<strong>ac</strong>uum pump in paperforming can save about 25% <strong>of</strong> electricity<br />
consumed.<br />
(iv) Change in pressing<br />
The use <strong>of</strong> longer nips or hot press which is heated by waste streams can save <strong>th</strong>e steam<br />
consumption <strong>of</strong> drying process by 15-20%.<br />
3.2.2.4 Waste heat recovery<br />
(i) Heat pump hot water system<br />
In <strong>th</strong>e drying process, <strong>th</strong>e water contained in <strong>th</strong>e paper is evaporated and is normally<br />
rejected to <strong>th</strong>e atmosphere. The energy content <strong>of</strong> evaporated water can be recovered by a<br />
heat pump to produce hot water for washing <strong>of</strong> <strong>th</strong>e pulp. This system can save about 1.3<br />
MJ per ton <strong>of</strong> paper.<br />
(ii) Flash steam recovery in drying process<br />
The typical pressure <strong>of</strong> steam used in <strong>th</strong>e drying process is 3-4 bar. The condensate coming<br />
from <strong>th</strong>e dryers is returned to <strong>th</strong>e condensate tank where some amount is flashed into <strong>th</strong>e<br />
environment. The flash steam can be recovered for fur<strong>th</strong>er use in <strong>th</strong>e processes by one <strong>of</strong><br />
<strong>th</strong>e following systems:<br />
- absorption heat transformer (energy saved = 200 MJ/ton <strong>of</strong> paper)<br />
- vapor compression heat pump (energy saved = 600 MJ/ton <strong>of</strong> paper)<br />
- ejecto-compressor (energy saved = 600 MJ/ton <strong>of</strong> paper)<br />
3.2.3 Long term measures<br />
The long term measures include better site arrangement <strong>of</strong> <strong>th</strong>e industry, excess power<br />
generation for <strong>th</strong>e grid, adaptation <strong>of</strong> <strong>th</strong>e new emerging processes and computerization <strong>of</strong><br />
<strong>th</strong>e manuf<strong>ac</strong>turing processes.
18 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
(i) Interconnected f<strong>ac</strong>tories: sugar mills and pulp mills<br />
The sugar industry, due to its generation <strong>of</strong> bagasse, is a very important source <strong>of</strong> raw<br />
material for pulping. By employing cogeneration, a well-designed sugar plant is normally<br />
able to produce its electricity while a considerable amount <strong>of</strong> excess bagasse still remains.<br />
This bagasse can be burnt in order to produce electricity if its buy-b<strong>ac</strong>k by <strong>th</strong>e grid is<br />
permitted. But bagasse can be used for pulping too. The coupling <strong>of</strong> a paper mill and a<br />
sugar plant is <strong>th</strong>erefore interesting.<br />
There are several modes <strong>of</strong> coupling <strong>th</strong>e two plants. Some possibilities are:<br />
- The sugar plant produces its electricity and sells excess bagasse to <strong>th</strong>e pulp plant.<br />
The latter produces electricity <strong>th</strong>rough cogeneration and combustion <strong>of</strong> bl<strong>ac</strong>k<br />
liquor.<br />
- Several sugar plants providing extra bagasse to one pulp plant; <strong>th</strong>e sugar mills and<br />
<strong>th</strong>e pulp mill are completely independent as far as energy use is concerned.<br />
- A pool is formed in order to manage <strong>th</strong>e energy usage jointly by <strong>th</strong>e sugar and<br />
pulp mills wi<strong>th</strong> any surplus electricity eventually sold b<strong>ac</strong>k to <strong>th</strong>e grid.<br />
This kind <strong>of</strong> management is very attr<strong>ac</strong>tive from <strong>th</strong>e point <strong>of</strong> view <strong>of</strong> appropriate use <strong>of</strong><br />
raw material and energy, and regional development, but several constraints must be taken<br />
into <strong>ac</strong>count:<br />
- Seasonal working conditions <strong>of</strong> <strong>th</strong>e sugar industry<br />
- Competition between <strong>th</strong>e buy-b<strong>ac</strong>k rate <strong>of</strong> electricity by <strong>th</strong>e grid (if allowed)<br />
and <strong>th</strong>e benefit <strong>of</strong> producing paper (wi<strong>th</strong> additional investment)<br />
- Technical problems related to pulping from bagasse, etc.<br />
(ii) Excess power generation<br />
The pulp and paper industry <strong>of</strong>fers <strong>th</strong>e pr<strong>ac</strong>tice <strong>of</strong> industrial cogeneration since <strong>th</strong>e<br />
demand <strong>of</strong> process steam is high. Since decentralization <strong>of</strong> power sector is beneficial bo<strong>th</strong><br />
at <strong>th</strong>e m<strong>ac</strong>ro and micro levels, excess power generation from <strong>th</strong>e pulp and paper industry<br />
should be a long term objective for better utilization <strong>of</strong> energy sources.<br />
(iii) Adaptation <strong>of</strong> new emerging processes<br />
The pulp and paper industry is one <strong>of</strong> <strong>th</strong>e most pollution producers in <strong>th</strong>e industrial sector.<br />
New pulping processes are still emerging (mentioned in <strong>th</strong>e following section) as clean<br />
technologies. Therefore adaptation <strong>of</strong> new emerging processes will enhance <strong>th</strong>e integrated<br />
appro<strong>ac</strong>h to energy and environment.
Energy Issues in <strong>th</strong>e Pulp and Paper Industry 19<br />
(iv) Computerization<br />
Like o<strong>th</strong>er industries, computer-control <strong>of</strong> processes in <strong>th</strong>e pulp and paper industry can<br />
result in a better management <strong>of</strong> all <strong>th</strong>e resources. The computerization will lead to <strong>th</strong>e<br />
reduction in fuel cost, chemicals, electrical charge and personnel services, etc., and<br />
guarantee a better quality pulp.<br />
As an example, <strong>th</strong>e pay-b<strong>ac</strong>k period <strong>of</strong> <strong>th</strong>e computer-controlled system in a Kraft pulp mill<br />
wi<strong>th</strong> a cap<strong>ac</strong>ity <strong>of</strong> 300 tons <strong>of</strong> pulp per day was estimated as less <strong>th</strong>an 6 years.<br />
3.3 New Energy Efficient Technologies for Papermaking<br />
Among <strong>th</strong>e new emerging processes, ozonation, BG-TAG-LAMORT process and<br />
organocell process are <strong>th</strong>e <strong>th</strong>ree most promising options.<br />
(i) Ozonation<br />
Ozone has a very high oxidizing and disinfecting power. Its use in water treatment is well<br />
established and is gradually increasing. The development <strong>of</strong> integrating an ozonizing stage<br />
into <strong>th</strong>e ble<strong>ac</strong>hing sequences in <strong>th</strong>e pulp and paper industry, however, is new and has been<br />
driven by environmental, economic and energy-related considerations. Energy requirement<br />
for ozone production has been consistently reduced during <strong>th</strong>e last ten years. Only 10<br />
kWh is now needed for <strong>th</strong>e production <strong>of</strong> 1 kg <strong>of</strong> ozone instead <strong>of</strong> <strong>th</strong>e 20 kWh required in<br />
<strong>th</strong>e past.<br />
Ozone is an oxide but it is a clean one. It can be used anytime <strong>th</strong>ere is a requirement <strong>of</strong> an<br />
oxidizer. Its uses for <strong>th</strong>e pulp industry can be <strong>th</strong>rough at least <strong>th</strong>ree options:<br />
- by repl<strong>ac</strong>ing chlorine as an environmentally safe ble<strong>ac</strong>hing agent in <strong>th</strong>e chemical<br />
process. The re<strong>ac</strong>tion can be carried out at room temperature and atmospheric<br />
pressure; 1% <strong>of</strong> ozone increases <strong>th</strong>e brightness <strong>of</strong> <strong>th</strong>e pulp from 45 up to 75 ISO<br />
in a single stage.<br />
- by re<strong>ac</strong>ting wi<strong>th</strong> lignin in <strong>th</strong>e <strong>th</strong>ermomechanical process and modifying its<br />
structure. About 2% <strong>of</strong> ozone appears to be able to keep a high yield <strong>of</strong> <strong>th</strong>e<br />
<strong>th</strong>ermomechanical process (around 90%) providing a streng<strong>th</strong> comparable to <strong>th</strong>at<br />
<strong>of</strong> <strong>th</strong>e chemical pulp.<br />
- in <strong>th</strong>e pollution abatement process, a specific quality <strong>of</strong> ozone for oxidizing at<br />
different levels can be used for classical type <strong>of</strong> water treatment, but it can also<br />
contribute to help in rapid flocculation or <strong>th</strong>e deterioration <strong>of</strong> microorganisms,<br />
for example.
20 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
An oxygen recycled process is also available, permitting considerable decrease in oxygen<br />
requirement. Oxygen process, however, requires to be carried out at high pressure and<br />
temperature.<br />
(ii) BG-TAG-LAMORT process<br />
One <strong>of</strong> <strong>th</strong>e main sources <strong>of</strong> pollution <strong>of</strong> <strong>th</strong>e pulp industry lies in <strong>th</strong>e cooking process as it<br />
needs chemical agents and a large quantity <strong>of</strong> water. The BG-TAG-LAMORT process<br />
uses a dry cooker to avoid <strong>th</strong>is problem. The raw material is soaked in a minimum amount<br />
<strong>of</strong> solution, so <strong>th</strong>at <strong>th</strong>e volume <strong>of</strong> bl<strong>ac</strong>k liquor is reduced and its concentration is high. The<br />
volume <strong>of</strong> water required can in f<strong>ac</strong>t be reduced 5 folds. The bl<strong>ac</strong>k liquor can be<br />
transferred directly to <strong>th</strong>e furn<strong>ac</strong>e <strong>of</strong> a boiler for combustion.<br />
This process is particularly suitable for small and medium size production plants and is well<br />
suited for raw materials such as bagasse. A plant producing 60,000 t/year <strong>of</strong> pulp costs<br />
about 80 million US dollars. The process is based on a 50 t/day module.<br />
(iii) Organocell process<br />
The objective is <strong>th</strong>e same as for <strong>th</strong>e o<strong>th</strong>er processes: reducing <strong>th</strong>e pollution as a result <strong>of</strong><br />
<strong>th</strong>e presence <strong>of</strong> sulfur in wastes.<br />
The organocell process extr<strong>ac</strong>ts <strong>th</strong>e lignin by alcohol, and sodium hydroxide. The<br />
advantage is a non-degradation <strong>of</strong> lignin. The interest lies in <strong>th</strong>e possibility <strong>of</strong> using lignin<br />
for producing chemical products such as polymers and derivatives. This process can be<br />
seen in <strong>th</strong>e light <strong>of</strong> a new biomass chemistry. The energy consumption is at <strong>th</strong>e level <strong>of</strong><br />
solvent regeneration.<br />
3.4 Concluding Remarks on Energy Issues<br />
The management pr<strong>ac</strong>tices to obtain better energy efficiency in <strong>th</strong>e pulp and paper industry<br />
are illustrated in Figure 3.4.<br />
The regular energy conservation pr<strong>ac</strong>tices such as insulation maintenance <strong>of</strong> steam lines,<br />
excess air control, checking <strong>of</strong> steam leakage, etc., can save certain amount <strong>of</strong> energy<br />
consumption, since <strong>th</strong>e pulp and paper industry consumes a large amount <strong>of</strong> steam. The<br />
temperature levels <strong>of</strong> processes are normally below 200°C. Therefore, application <strong>of</strong><br />
<strong>th</strong>ermal upgrading systems can <strong>of</strong>fer significant energy savings, especially in <strong>th</strong>e large mills.<br />
The higher recovery rate <strong>of</strong> chemicals and materials is also an important issue in <strong>th</strong>e pulp<br />
and paper industry for <strong>th</strong>e preservation <strong>of</strong> resources. Since <strong>th</strong>e full utilization <strong>of</strong> internal<br />
energy sources is <strong>th</strong>e major goal for higher energy efficiency, cogeneration and me<strong>th</strong>ane<br />
production would be beneficial bo<strong>th</strong> at <strong>th</strong>e plant and m<strong>ac</strong>ro levels.
Energy Issues in <strong>th</strong>e Pulp and Paper Industry 21<br />
Fuel<br />
(external + internal)<br />
Cogeneration<br />
Membrane<br />
Seperation<br />
Management Pr<strong>ac</strong>tices Benefits<br />
To<br />
Grid<br />
Thermal<br />
Upgrading<br />
Electricity<br />
Effluent<br />
Me<strong>th</strong>ane<br />
Production<br />
Ozonation<br />
- Rational use <strong>of</strong><br />
energy sources<br />
- Energy recovery<br />
- Depollution<br />
- Fibre recovery<br />
- Water<br />
recycling<br />
- Depollution<br />
- Chemical saving<br />
- Energy recovery<br />
- Water saving<br />
- Depollution<br />
- Energy Saving<br />
Figure 3.4. Management pr<strong>ac</strong>tices for better energy efficiency
22 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
4. SOURCES OF POLLUTION AND ITS MANAGEMENT<br />
4.1 Sources and Char<strong>ac</strong>teristics <strong>of</strong> Pollutants<br />
The major environmental problems in <strong>th</strong>e pulp and paper industry come from <strong>th</strong>e<br />
production <strong>of</strong> pulp. Different me<strong>th</strong>ods are used for pulp production. The specific<br />
environmental effects vary depending upon <strong>th</strong>e pulping process used. Mechanical pulping<br />
requires relatively small quantities <strong>of</strong> water for chipping and milling <strong>of</strong> <strong>th</strong>e fibers and <strong>th</strong>is<br />
water is only slightly polluted. On <strong>th</strong>e o<strong>th</strong>er hand, chemical pulping requires large quantities<br />
<strong>of</strong> water and causes severe water pollution. The use <strong>of</strong> chemical pulping is, <strong>th</strong>erefore,<br />
restricted to areas where a large receiving water body is available to absorb <strong>th</strong>e<br />
contaminants remaining after <strong>th</strong>e treatment <strong>of</strong> wastewater.<br />
Water-, air-, solid- and indirect pollutants are generated from <strong>th</strong>e different processes.<br />
Suspended solids and dissolved organic substances (including lignin) <strong>th</strong>at are not readily<br />
biodegradable are <strong>th</strong>e major pollutants. Most air pollution problems are related to sulfur<br />
and sulfur dioxide and o<strong>th</strong>er sulfur compounds.<br />
4.1.1 Sources <strong>of</strong> wastewater generated<br />
The sources and char<strong>ac</strong>teristics <strong>of</strong> wastewater in <strong>th</strong>e pulp and paper industry are as follows:<br />
(i) Chipping<br />
Wastewater from <strong>th</strong>e chipping process contains coarse materials, i.e. barks and chips.<br />
(ii) Bl<strong>ac</strong>k liquor<br />
Bl<strong>ac</strong>k liquor is <strong>th</strong>e wastewater from <strong>th</strong>e digestion and <strong>th</strong>e rinsing process.<br />
(iii) Evaporator condensate<br />
The condensate from <strong>th</strong>e evaporator in <strong>th</strong>e chemical recovery process contains odorous<br />
alkyl sulfides, which is treated by steam stripping before being transferred to <strong>th</strong>e treatment<br />
plant. This wastewater is rich in <strong>ac</strong>etate and me<strong>th</strong>anol and is usually treated wi<strong>th</strong> o<strong>th</strong>er<br />
wastewater.<br />
(iv) Wastewater from ble<strong>ac</strong>hing<br />
The most problematic wastewater generated in ble<strong>ac</strong>hed Kraft pulp (BKP) production is<br />
from <strong>th</strong>e ble<strong>ac</strong>hing process, especially in <strong>th</strong>e initial ble<strong>ac</strong>hing stages. It contains<br />
hard-biodegradable organics (such as lignin and hemicellulose), chlorinated organics and<br />
dioxin, and 2,3,7,8-tetr<strong>ac</strong>hlorodibenzo-p-dioxin (2,3,7,8-TCDD) compounds. Fur<strong>th</strong>ermore,<br />
it is highly colored wi<strong>th</strong> brown substances. The effluents not only have negative imp<strong>ac</strong>t on<br />
plant and animal life in <strong>th</strong>e receiving areas, but are also “persistent”, i.e., <strong>th</strong>ey bio-degrade<br />
very slowly.
Sources <strong>of</strong> Pollution and its Management in <strong>th</strong>e Pulp and Paper Industry 23<br />
(v) White water<br />
Wastewater from <strong>th</strong>e paper making process contains fine fibers and o<strong>th</strong>er solids such as<br />
fillers. The excess white water after fiber recovery is treated by coagulation/flocculation<br />
process and is discharged to <strong>th</strong>e treatment plant.<br />
4.1.2 Char<strong>ac</strong>teristics <strong>of</strong> wastewater generated<br />
The wastewater <strong>of</strong> pulp and paper effluents may contain dissolved organic compounds and<br />
chemicals used in <strong>th</strong>e process, fibers, fillers and additives, color, bark, ash and lime sludge.<br />
The dissolved compounds originate in pulping process, suspended solids are present in<br />
effluents from pr<strong>ac</strong>tically all stages and parts <strong>of</strong> <strong>th</strong>e industry. The suspended matter<br />
consists generally <strong>of</strong> fibers and bark residue, ash lime and clay. Dissolved organic<br />
substances include lignin, carbohydrates, organic <strong>ac</strong>ids and alcohol which, wi<strong>th</strong> <strong>th</strong>e<br />
exception <strong>of</strong> lignin, are readily biodegradable.<br />
Conventional parameters to quantify <strong>th</strong>e pollution load are biochemical oxygen demand<br />
(BOD 5), dry solids (DS) and pH. Toxic pollutants present are pent<strong>ac</strong>hlorophenol (PCP),<br />
trichlorophenol (TCP), zinc, chlor<strong>of</strong>orm, ble<strong>ac</strong>h plant derivatives, PCB-1 2 4 2, o<strong>th</strong>er<br />
pollutants, ammonia, color, resin, and <strong>ac</strong>ids.<br />
The effluent char<strong>ac</strong>teristics <strong>of</strong> different ble<strong>ac</strong>hed Kraft pulp mills in Sweden and Finland<br />
are shown in Table 4.1.<br />
Table 4.1. Effluent from ble<strong>ac</strong>hed Kraft pulp mills prior to external treatment<br />
Type <strong>of</strong> wood and <strong>Technology</strong><br />
S<strong>of</strong>t wood<br />
BOD7 kg/t<br />
COD<br />
kg/t<br />
SS<br />
kg/t<br />
TOCl<br />
kg/t<br />
<strong>Technology</strong> in Finland & Sweden 1970<br />
<strong>Technology</strong> in Finland 1988<br />
<strong>Technology</strong> in Sweden 1988<br />
Hard wood<br />
55<br />
24<br />
19<br />
190<br />
85<br />
65<br />
15<br />
11<br />
8<br />
>6<br />
5<br />
3.5<br />
<strong>Technology</strong> in Finland & Sweden 1970<br />
<strong>Technology</strong> in Finland 1988<br />
<strong>Technology</strong> in Sweden 1988<br />
60<br />
25<br />
25<br />
180<br />
75<br />
75<br />
28<br />
12<br />
9<br />
4<br />
2.5<br />
2.5<br />
Source: Adapted from BONSOR et al, 1988<br />
The char<strong>ac</strong>teristic <strong>of</strong> de-inking wastewater from paper industry where waste paper is used<br />
as raw material is given in Table 4.2.
24 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Table 4.2. Char<strong>ac</strong>teristics <strong>of</strong> de-inking wastewater from waste paper mill<br />
Country Flow rate<br />
m 3 TSS BOD COD Product<br />
/ t kg / t kg / t kg / t<br />
Philippine paper mill 26 10.0 5.0 Newsprint<br />
German paper mill 10.5 4.7 10.5 Carton<br />
German paper mill 4.2 5.9 13.4 Testliner paper<br />
Source: Adapted from C. T. Tupas, 1995<br />
Char<strong>ac</strong>teristics <strong>of</strong> combined effluent <strong>of</strong> pulp and paper mills, and distribution <strong>of</strong> pollution<br />
load from different sections <strong>of</strong> pulp and paper mills are shown in Table 4.3.<br />
Table 4.3. Char<strong>ac</strong>teristics <strong>of</strong> combined effluent <strong>of</strong> pulp and paper mills and<br />
distribution <strong>of</strong> pollution load from different sections <strong>of</strong> a mill<br />
Item Small mill<br />
Large mill<br />
(Sastry et al.)<br />
(Subrahmanyam et al.)<br />
Produces 20 tons <strong>of</strong> paper Produces 2000 tons <strong>of</strong> paper<br />
Flow per day<br />
Color<br />
pH<br />
Total solids, mg /l<br />
Suspended solids mg /l<br />
COD mg /l<br />
BOD mg /l<br />
COD/BOD ratio<br />
Flow %<br />
Small<br />
Large<br />
BOD %<br />
Small<br />
Large<br />
Suspended Solid %<br />
Small<br />
Large<br />
per day<br />
330 m 3 / t<br />
-<br />
8.2-8.5<br />
-<br />
900-2000<br />
4300-5780<br />
680-1250<br />
3.9-5<br />
Item Digester<br />
section<br />
45.5<br />
9.75<br />
66<br />
32.5<br />
60<br />
3<br />
Ble<strong>ac</strong>hing<br />
section<br />
16.2<br />
27.8<br />
18.4<br />
32.5<br />
14.5<br />
1.35<br />
per day<br />
222 m 3 / t<br />
7800 units<br />
8.5-9.5<br />
4410<br />
3300<br />
716<br />
155<br />
4.6<br />
Paper mill<br />
section<br />
10.8<br />
16.7<br />
2<br />
1.43<br />
7.75<br />
3.4
Sources <strong>of</strong> Pollution and its Management in <strong>th</strong>e Pulp and Paper Industry 25<br />
4.1.3 Sources and char<strong>ac</strong>teristics <strong>of</strong> gaseous emissions<br />
Gaseous emissions <strong>of</strong> concern are <strong>th</strong>e discharges <strong>of</strong> <strong>th</strong>ose components considered as air<br />
pollutants and odorous components. These pollutants <strong>of</strong> <strong>th</strong>e pulping industry, especially<br />
from chemical pulping, are hydrogen sulfides, organic sulfide, SO x and NO x.<br />
The release <strong>of</strong> sulfur containing gases during Kraft digestion and burning <strong>of</strong> bl<strong>ac</strong>k liquor<br />
generates H 2S, a highly malodorous gas, SO 2, and various me<strong>th</strong>yl derivatives such as me<strong>th</strong>yl<br />
mercaptan (CH 3SH), dime<strong>th</strong>yl sulfide (CH 3) 2S, and dime<strong>th</strong>yl disulfide (CH 3-S-S-CH 3) .<br />
Odorous components as phenols and turpenes are liberated from all o<strong>th</strong>er pulping<br />
processes.<br />
4.1.4 Sources and char<strong>ac</strong>teristics <strong>of</strong> solid wastes<br />
The pulp and paper industry produces solid wastes which, depending on <strong>th</strong>e pulping<br />
process and <strong>th</strong>e chemical processing, consist <strong>of</strong> waste water sludge, ash, bark, woodwaste<br />
and paper. These wastes have high pollution potential and should be disposed <strong>of</strong> in<br />
controlled landfills to avoid le<strong>ac</strong>hing <strong>of</strong> <strong>th</strong>e sub-soil.<br />
4.2 Current Pollution Abatement Strategies and Technologies<br />
4.2.1 Water pollution control<br />
Pulp and paper mill wastes are treated by <strong>th</strong>e following processes:<br />
- Recovery processes.<br />
- Sedimentation and floatation to remove suspended matter.<br />
- Chemical precipitation to remove color and suspended and colloidal particulate<br />
matter.<br />
- Biological treatment to remove oxygen demanding matter/dissolved organic<br />
matter.<br />
The treatment <strong>of</strong> waste water may consist <strong>of</strong> all or a combination <strong>of</strong> some <strong>of</strong> <strong>th</strong>ese<br />
processes.<br />
(i) Recovery processes<br />
The recovery <strong>of</strong> <strong>th</strong>e process chemicals and fibers reduces <strong>th</strong>e pollution load to a great<br />
extent. Where <strong>th</strong>e economy permits, <strong>th</strong>e color bearing ‘bl<strong>ac</strong>k liquor’ is treated for <strong>th</strong>e<br />
recovery <strong>of</strong> chemicals. However, in <strong>th</strong>is process <strong>th</strong>e lignin is destroyed. The lignin may be<br />
recovered from <strong>th</strong>e bl<strong>ac</strong>k liquor by precipitation and by <strong>ac</strong>idulation wi<strong>th</strong> ei<strong>th</strong>er carbon<br />
dioxide or sulfuric <strong>ac</strong>id. These recovered lignins have got various uses in o<strong>th</strong>er industries.<br />
The alkali lignins <strong>of</strong> Kraft process may be used as a dispersing agent in various<br />
suspensions. Lignins may be used as raw materials for various o<strong>th</strong>er substances, e.g.<br />
dime<strong>th</strong>yl sulfur oxide, which is used as spinning solvent for poly<strong>ac</strong>rylonitrile fibers.<br />
Activated carbon may also be manuf<strong>ac</strong>tured from <strong>th</strong>e lignin recovered from bl<strong>ac</strong>k liquors.
26 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
The fibers in <strong>th</strong>e white water from <strong>th</strong>e paper mills are recovered ei<strong>th</strong>er by sedimentation or<br />
by floatation using forced air in <strong>th</strong>e tank.<br />
The recovery <strong>of</strong> lime from <strong>th</strong>e lime mud can be <strong>ac</strong>hieved by <strong>th</strong>e process <strong>of</strong> calcination.<br />
(ii) Chemical treatment for color removal<br />
The chemical coagulation for <strong>th</strong>e removal <strong>of</strong> color is found to be uneconomical. Attempts<br />
have been made to recover color from <strong>th</strong>e waste using <strong>th</strong>e lime sludge; <strong>th</strong>e results are not<br />
at all encouraging. “Massive Lime Treatment” process, developed by <strong>th</strong>e National Council for<br />
Stream Improvement in <strong>th</strong>e USA is said to be capable <strong>of</strong> removing about 90% <strong>of</strong> color and<br />
40 to 60% <strong>of</strong> BOD from <strong>th</strong>e waste. In <strong>th</strong>is process, <strong>th</strong>e entire quantity <strong>of</strong> lime, normally<br />
required for <strong>th</strong>e re-causticization <strong>of</strong> green liquor into white liquor, is allowed to re<strong>ac</strong>t wi<strong>th</strong><br />
<strong>th</strong>e colored waste effluent first. The color is absorbed by <strong>th</strong>e lime, and <strong>th</strong>e sludge after<br />
settling is used in recausticizing <strong>th</strong>e green liquor. The treatment <strong>of</strong> green liquor wi<strong>th</strong><br />
colored lime sludge results in <strong>th</strong>e formation <strong>of</strong> dark brown liquor, containing bo<strong>th</strong> desired<br />
cooking chemicals and color-producing components, like lignin. The lignin-bearing liquor<br />
is used as digested liquid, and <strong>th</strong>en is destroyed along wi<strong>th</strong> <strong>th</strong>e fresh lignins in <strong>th</strong>e<br />
subsequent operations <strong>of</strong> concentration and incineration in <strong>th</strong>e process <strong>of</strong> chemical<br />
recovery.<br />
In a study conducted by NEERI, it has been observed <strong>th</strong>at <strong>ac</strong>idic <strong>ac</strong>tivated carbon can<br />
remove up to 94% <strong>of</strong> <strong>th</strong>e color from <strong>th</strong>e pulp mill waste. However, pH <strong>of</strong> <strong>th</strong>e waste is<br />
required to be reduced to 3.0 before <strong>th</strong>is <strong>ac</strong>tivated carbon treatment.<br />
(iii) Physical treatment for clarification<br />
Mechanically cleaned circular clarifiers alone are capable <strong>of</strong> 70-80% removal <strong>of</strong> <strong>th</strong>e<br />
suspended solids from <strong>th</strong>e combined mill effluent. About 95 to 99% removal <strong>of</strong> settleable<br />
solids can be <strong>ac</strong>complished in <strong>th</strong>e clarifiers. However, <strong>th</strong>e BOD reduction is comparatively<br />
small and <strong>of</strong> <strong>th</strong>e order <strong>of</strong> 25-40% only. A surf<strong>ac</strong>e loading in <strong>th</strong>e order <strong>of</strong> 30 to 31<br />
m 3 /m 2 /day is found to be adequate for up to 79% removal <strong>of</strong> suspended solids and 52%<br />
removal <strong>of</strong> COD at a detention time <strong>of</strong> 30 minutes.<br />
The primary sludge produced in <strong>th</strong>e clarifiers can be <strong>th</strong>ickened to such a consistency in <strong>th</strong>e<br />
clarifier itself <strong>th</strong>at it can be easily dewatered mechanically.<br />
(iv) Biological treatment <strong>of</strong> <strong>th</strong>e waste<br />
Considerable reduction <strong>of</strong> BOD from <strong>th</strong>e waste can be <strong>ac</strong>complished in bo<strong>th</strong> conventional<br />
and low cost biological treatment processes. Some are also effective in <strong>th</strong>e reduction <strong>of</strong><br />
color from <strong>th</strong>e waste.
Sources <strong>of</strong> Pollution and its Management in <strong>th</strong>e Pulp and Paper Industry 27<br />
If sufficient area is available, <strong>th</strong>e waste stabilization ponds <strong>of</strong>fer <strong>th</strong>e cheapest means for<br />
treatment. Dep<strong>th</strong> <strong>of</strong> <strong>th</strong>ese ponds vary from 0.9 m to 1.5 m; <strong>th</strong>e detention period may vary<br />
from 12 to 30 days. A minimum <strong>of</strong> 85% removal <strong>of</strong> BOD is <strong>ac</strong>hievable, wi<strong>th</strong> a loading rate<br />
<strong>of</strong> up to 56 kg/hectare/day.<br />
Aerated lagoons are <strong>th</strong>e improved forms <strong>of</strong> <strong>th</strong>e stabilization ponds. They can be adopted to<br />
upgrade <strong>th</strong>e performance <strong>of</strong> already present quiescent stabilization ponds <strong>th</strong>at have become<br />
inadequate because <strong>of</strong> <strong>th</strong>e increased loading or more stringent receiving water criteria. The<br />
mechanical surf<strong>ac</strong>e aerators are <strong>th</strong>e most satisf<strong>ac</strong>tory oxygen transfer device. BOD<br />
reduction up to 50 to 95% can be <strong>ac</strong>hieved in <strong>th</strong>e aerated lagoons by varying nutrients feed,<br />
air supply and detention time (3 to 20 days), at <strong>th</strong>e loading range <strong>of</strong> 670 to 1340 kg <strong>of</strong> BOD<br />
per hectare per day. Aerated lagoons are employed, ei<strong>th</strong>er when <strong>th</strong>e effluent BOD is<br />
moderate (where a partial chemical recovery from <strong>th</strong>e bl<strong>ac</strong>k liquor is pr<strong>ac</strong>ticed), or as a<br />
polishing device. In one particular case, a detention period <strong>of</strong> 5 days was found adequate<br />
for 90% BOD removal; <strong>th</strong>e system rate constant was found to be 0.21/day. It may be<br />
noted <strong>th</strong>at <strong>th</strong>e pulp and paper mill waste does not contain necessary nutrients for <strong>th</strong>e<br />
b<strong>ac</strong>terial grow<strong>th</strong>, and hence nitrogen and phosphorous are to be added into <strong>th</strong>e lagoons in<br />
<strong>th</strong>e form <strong>of</strong> urea or ammonia and phosphoric <strong>ac</strong>id in a BOD:N:P ratio <strong>of</strong> 100:5:1. The<br />
nutrient addition is not necessary when a detention period <strong>of</strong> more <strong>th</strong>an 10-15 days are<br />
provided.<br />
Segregated strong waste or combined wastes may be well treated in Anaerobic lagoons wi<strong>th</strong><br />
nutrient supplement. A BOD loading <strong>of</strong> 0.048 kg/m 3 /day and a detention time <strong>of</strong> 20 days<br />
were found to be adequate for 72.5% removal <strong>of</strong> BOD in a particular case. In ano<strong>th</strong>er case,<br />
77.5% removal <strong>of</strong> BOD was reported at a detention time <strong>of</strong> 6-8 days and a loading <strong>of</strong> 0.017<br />
kg <strong>of</strong> BOD/m 3 /day. Aerated lagoons may be employed after <strong>th</strong>e anaerobic lagoons where<br />
a high effluent quality is required. The system rate constant in <strong>th</strong>e aerated lagoons,<br />
preceded by <strong>th</strong>e anaerobic lagoons may be taken as 0.15-0.17 per day. A detention period<br />
<strong>of</strong> 7 days in <strong>th</strong>ese aerated lagoons are adequate.<br />
Activated sludge process is <strong>th</strong>e most satisf<strong>ac</strong>tory and sophisticated system for <strong>th</strong>e effluent<br />
treatment. Instead <strong>of</strong> porous diffusers, <strong>th</strong>e surf<strong>ac</strong>e aerators are <strong>of</strong>ten suggested as <strong>th</strong>e<br />
oxygen transfer device in <strong>th</strong>e aeration tanks treating pulp and paper mill effluent. It is<br />
reported <strong>th</strong>at about 80 to 90% BOD removal can be <strong>ac</strong>hieved wi<strong>th</strong> a loading rate <strong>of</strong> 0.2 to<br />
0.3 kg <strong>of</strong> BOD per kg <strong>of</strong> MLSS for a detention time <strong>of</strong> 3 to 9 hours, MLSS concentration<br />
<strong>of</strong> 2000-4000 mg/l, recirculation ratio <strong>of</strong> 0.3-0.5, and a nutrient supplement at <strong>th</strong>e<br />
BOD:N:P ratio <strong>of</strong> 100:5:1.<br />
While designing <strong>th</strong>e secondary settling tank in an <strong>ac</strong>tivated sludge process, it should be<br />
borne in mind <strong>th</strong>at a large portion <strong>of</strong> <strong>th</strong>e fine fibers is not biodegradable and also does not<br />
settle easily. Flow diagram for <strong>th</strong>e treatment <strong>of</strong> waste from a typical pulp mill is given in<br />
Figure 4.1.
28 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Bl<strong>ac</strong>k<br />
Liquor<br />
O<strong>th</strong>er<br />
Waste<br />
Lime<br />
Lime<br />
treatment<br />
Clarifier<br />
Calcium Hypochloride<br />
Grift Cham Clarifier<br />
Cooling<br />
Tower<br />
Nutrients<br />
BOD reduction 87%<br />
Detention Time 1.5 days<br />
Anaerobic<br />
Lagoon<br />
Stabilization<br />
Tank<br />
Aerated<br />
Lagoon<br />
Colour reduction=70%<br />
BOD reduction=40-50%<br />
Detention time=4 Hrs<br />
Detention Time<br />
= 3 Days<br />
Aerated<br />
Lagoon<br />
Figure 4.1 Flow diagram <strong>of</strong> wastewater treatment <strong>of</strong> a typical pulp mill<br />
Effluent<br />
Trickling filter has got a limited use in <strong>th</strong>e treatment <strong>of</strong> <strong>th</strong>e pulp and paper mill effluent,<br />
due to <strong>th</strong>e greater chances <strong>of</strong> clogging <strong>of</strong> <strong>th</strong>e media wi<strong>th</strong> fibrous material. Also <strong>th</strong>e trickling<br />
filter system is not capable <strong>of</strong> providing a high degree <strong>of</strong> treatment even wi<strong>th</strong> <strong>th</strong>e new<br />
plastic media. Wi<strong>th</strong> greater specific surf<strong>ac</strong>e area, <strong>th</strong>e BOD removal is found to be only 40-<br />
50%.<br />
(vi) Land treatment me<strong>th</strong>od<br />
Some types <strong>of</strong> soil are capable <strong>of</strong> removing color from <strong>th</strong>e waste. The waste is stored and<br />
allowed to be absorbed in such a soil. The capability <strong>of</strong> <strong>th</strong>e soil in removing <strong>th</strong>e color<br />
depends on <strong>th</strong>e cation exchange cap<strong>ac</strong>ity <strong>of</strong> <strong>th</strong>e soil. In addition to cation exchange<br />
cap<strong>ac</strong>ity, <strong>th</strong>e soil should be sufficiently permeable to <strong>ac</strong>cept <strong>th</strong>e entire volume <strong>of</strong> waste.<br />
(vii) Disposal <strong>of</strong> waste by irrigation<br />
The pulp mill effluent may be utilized for irrigation. No adverse effect on crops are<br />
reported for crops like maize, paddy, jowar and kenaf. Yields almost identical to <strong>th</strong>ose wi<strong>th</strong><br />
conventional irrigation pr<strong>ac</strong>tices are reported for wheat and sugarcane (RAO & DATTA,<br />
1987).
Sources <strong>of</strong> Pollution and its Management in <strong>th</strong>e Pulp and Paper Industry 29<br />
4.2.2 Solid waste disposal<br />
Application <strong>of</strong> incineration furn<strong>ac</strong>e for heat/energy recovery from combustion <strong>of</strong> fibers,<br />
barks, wood residues, o<strong>th</strong>er organic materials and wastewater sludge is pr<strong>ac</strong>ticed today but<br />
still needs more attention.<br />
4.3 Possibilities for Application <strong>of</strong> Alternative Technologies for Pollution Control<br />
Since it is impossible to completely eliminate <strong>th</strong>e waste coming out <strong>of</strong> <strong>th</strong>e production<br />
process, it is always necessary to have some sort <strong>of</strong> end-<strong>of</strong>-<strong>th</strong>e-pipe treatment to meet <strong>th</strong>e<br />
stringent environmental discharge regulations. There have been numerous developments<br />
towards cleaner production opportunities in <strong>th</strong>e industry. In <strong>th</strong>is section some <strong>of</strong> <strong>th</strong>e recent<br />
technological developments on bo<strong>th</strong> end-<strong>of</strong>-<strong>th</strong>e-pipe treatment and production process<br />
modification as well as raw material changes for waste reduction are discussed.<br />
4.3.1 Anaerobic treatment <strong>of</strong> wastes<br />
In recent years, <strong>th</strong>e trend in <strong>th</strong>e industry has changed from resource-destroying aerobic to<br />
resource-conserving anaerobic wastewater treatment. By anaerobic treatment, a<br />
combination <strong>of</strong> energy-efficient wastewater purification and energy recovery in <strong>th</strong>e form <strong>of</strong><br />
biogas production can be <strong>ac</strong>hieved. Such a full-scale application <strong>of</strong> anaerobic process is<br />
widespread in <strong>th</strong>e developed countries. Originally, conventional anaerobic treatment in an<br />
economic manner required highly concentrated wastewater. The development <strong>of</strong> anaerobic<br />
process-technology during recent years has drastically reduced <strong>th</strong>is requirement.<br />
Pulp and paper industries discharge large quantities <strong>of</strong> fibers and different types <strong>of</strong> sludge.<br />
These wastes correspond to large quantities <strong>of</strong> energy consumed by <strong>th</strong>e treatment and<br />
disposal process and large amounts <strong>of</strong> potential energy stored in <strong>th</strong>e materials. Because <strong>of</strong><br />
<strong>th</strong>e savings in processing energy and <strong>th</strong>e recovery <strong>of</strong> potential energy, <strong>th</strong>e demand for using<br />
anaerobic treatment <strong>of</strong> <strong>th</strong>ese wastes has greatly increased.<br />
4.3.2 Membrane technology<br />
Several membrane processes (reverse osmosis, electrodialysis, and ultrafiltration) have<br />
recently been developed to treat <strong>th</strong>e wastewater. Electrodialysis procedures have been<br />
successfully used to treat bisulfite spent liquor generated in a sulfite pulping process. In<br />
electrodialysis process, an imposed electric current is used to cause selective movement <strong>of</strong><br />
charged ions. A traditional electrodialysis system can be modified for <strong>th</strong>is particular<br />
application by pl<strong>ac</strong>ing sulfurous <strong>ac</strong>id (H 2SO 3) in several compartments and <strong>th</strong>e spent liquor<br />
(containing large amounts <strong>of</strong> lignosulfonic <strong>ac</strong>id sodium salt and small amounts <strong>of</strong> nonionizable<br />
sugars) in ano<strong>th</strong>er set <strong>of</strong> compartments. The compartments and membranes are<br />
arranged such <strong>th</strong>at <strong>th</strong>e sodium and bisulfite ions combine in a <strong>th</strong>ird set <strong>of</strong> compartments,<br />
forming sodium bisulfite (NaHSO 3). This NaHSO 3 can be recycled as cooking liquor. In
30 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
addition, <strong>th</strong>e remaining mixture <strong>of</strong> sugars and lignosulfonic <strong>ac</strong>id can be sold as plywood<br />
adhesives. One difficulty wi<strong>th</strong> <strong>th</strong>e process is high power requirement.<br />
The greater amount <strong>of</strong> dilute wastes, arising primarily from <strong>th</strong>e washing <strong>of</strong> pulp for fur<strong>th</strong>er<br />
lignin removal, also constitutes a serious waste problem. Typically, <strong>th</strong>is wastewater may<br />
contain about 1% dissolved solids. These dilute streams can be treated by a combination <strong>of</strong><br />
ultra-filtration followed by reverse osmosis, or by just <strong>th</strong>e reverse osmosis step. The<br />
purified water can be returned to <strong>th</strong>e system; <strong>th</strong>e small-volume concentrated wastes can<br />
<strong>th</strong>en be treated as digester wastes.<br />
4.3.3 Dissolved air floatation for fiber recovery<br />
This process is based on <strong>th</strong>e f<strong>ac</strong>t <strong>th</strong>at, addition <strong>of</strong> air to <strong>th</strong>e waste stream could enhance <strong>th</strong>e<br />
natural propensity <strong>of</strong> <strong>th</strong>e fibers to float, <strong>th</strong>ereby separating <strong>th</strong>em from <strong>th</strong>e water. Initially,<br />
polymeric flocculating agents are added, causing <strong>th</strong>e suspended fibers to coagulate toge<strong>th</strong>er<br />
into flocs. The stream is <strong>th</strong>en mixed wi<strong>th</strong> water in which air has been dissolved under<br />
pressure. When <strong>th</strong>e pressure is released, air comes out <strong>of</strong> solution as small bubbles which<br />
att<strong>ac</strong>h <strong>th</strong>emselves to <strong>th</strong>e flocs, bringing <strong>th</strong>em to <strong>th</strong>e surf<strong>ac</strong>e from where <strong>th</strong>ey can be readily<br />
skimmed <strong>of</strong>f. The success <strong>of</strong> <strong>th</strong>e technology is due to:<br />
- its versatility and ease <strong>of</strong> operation.<br />
- <strong>th</strong>e economic returns associated wi<strong>th</strong> fiber recovery.<br />
- substantially reduced residence times, which removes <strong>th</strong>e possibility <strong>of</strong> any<br />
organic material becoming contaminated by microorganisms, and speedy recirculation,<br />
<strong>th</strong>ereby limiting <strong>th</strong>e loss <strong>of</strong> process heat.<br />
- levels <strong>of</strong> clarification superior to what can be <strong>ac</strong>hieved wi<strong>th</strong> traditional me<strong>th</strong>ods.<br />
4.3.4 Ozone ble<strong>ac</strong>hing<br />
The 5-stage ble<strong>ac</strong>hing sequence (CEDED process) is <strong>th</strong>e most common and one <strong>of</strong> <strong>th</strong>e<br />
most economical ble<strong>ac</strong>hing processes for <strong>th</strong>e pulp. For e<strong>ac</strong>h stage, <strong>th</strong>e dissolved organics<br />
and <strong>th</strong>e inorganic ble<strong>ac</strong>hing chemicals must be washed out <strong>of</strong> <strong>th</strong>e pulp before entering <strong>th</strong>e<br />
next stage. Al<strong>th</strong>ough <strong>th</strong>e amount <strong>of</strong> wash water and <strong>th</strong>e resulting effluent could be<br />
minimized by reuse <strong>of</strong> <strong>th</strong>e washings as wash water for <strong>th</strong>e prior stage in a counter-current<br />
feedb<strong>ac</strong>k fashion, eventually it is necessary to sewer all <strong>th</strong>e washings for treatment in <strong>th</strong>e<br />
plant’s effluent treatment system. The result is a high BOD, high COD, high color and<br />
highly chlorinated solution <strong>of</strong> organics, which are formed principally from <strong>th</strong>e re<strong>ac</strong>tion <strong>of</strong><br />
chlorine wi<strong>th</strong> pulp.<br />
The repl<strong>ac</strong>ement manuf<strong>ac</strong>turing process is a 4-stage ble<strong>ac</strong>hing sequence, using oxygen wi<strong>th</strong><br />
caustic as <strong>th</strong>e ble<strong>ac</strong>hing agents in <strong>th</strong>e first stage (O), followed by ozone treatment in <strong>th</strong>e<br />
second stage (Z), caustic extr<strong>ac</strong>tion augmented by oxygen in <strong>th</strong>e <strong>th</strong>ird stage (EO), and a<br />
final chlorine dioxide stage (D). Since <strong>th</strong>ere is no use in <strong>th</strong>e O, Z, or EO stages <strong>of</strong><br />
chemicals <strong>th</strong>at are incompatible wi<strong>th</strong> recycle and recovery in <strong>th</strong>e mill’s existing pulping
Sources <strong>of</strong> Pollution and its Management in <strong>th</strong>e Pulp and Paper Industry 31<br />
liquor closed-cycle system, virtually all <strong>of</strong> <strong>th</strong>e washings from <strong>th</strong>ese <strong>th</strong>ree stages are<br />
recovered wi<strong>th</strong>out sewering. The only significant effluent from <strong>th</strong>e ble<strong>ac</strong>h plant is <strong>th</strong>e small<br />
amount <strong>of</strong> contaminated washings coming out <strong>of</strong> <strong>th</strong>e final chlorine dioxide stage. This<br />
process is successfully used in <strong>th</strong>e USA.<br />
Since essentially all <strong>th</strong>e caustic used in <strong>th</strong>e oxygen stage treatment <strong>of</strong> <strong>th</strong>e OZ(EO)D<br />
ble<strong>ac</strong>hing is recovered and recycled b<strong>ac</strong>k to <strong>th</strong>e cooking liquor closed recycle system, one is<br />
able to use it as <strong>th</strong>e caustic for <strong>th</strong>e oxygen stage when caustic makeup is needed for <strong>th</strong>e<br />
cooking liquor cycle, disposing <strong>of</strong> <strong>th</strong>e cost for purchasing additional caustic. However,<br />
when no caustic make-up is required, one can oxidize wi<strong>th</strong> oxygen <strong>th</strong>e product from <strong>th</strong>e<br />
cooking liquor recycle (white liquor) and use <strong>th</strong>e oxidized white liquor for <strong>th</strong>e alkali<br />
requirement. This results in an extra load (regeneration load <strong>of</strong> about 5% more cooking<br />
liquor for <strong>th</strong>e pine pulp) on <strong>th</strong>e cooking liquor recycle equipment’s cap<strong>ac</strong>ity.<br />
The recovery and recycle <strong>of</strong> organic and inorganic solids, purged in <strong>th</strong>e ble<strong>ac</strong>h plant<br />
effluents, give about 7% more solids <strong>th</strong>an normal for pine pulp production. While it is true<br />
<strong>th</strong>at <strong>th</strong>is is an extra use <strong>of</strong> recovery cap<strong>ac</strong>ity, it also results in extra solids which may be<br />
used as fuel for producing steam in <strong>th</strong>e recovery boiler. About 6% more steam per ton <strong>of</strong><br />
pine pulp can be produced.<br />
4.3.5 Modified continuous cooking process (MCC)<br />
MCC adapts <strong>th</strong>e principles <strong>of</strong> extended delignification to continuous pulping and rectifies<br />
<strong>th</strong>e drawb<strong>ac</strong>ks <strong>of</strong> a conventional, continuous Kraft cook. The effective alkali concentration<br />
<strong>th</strong>rough <strong>th</strong>e duration <strong>of</strong> cooking is evened out by decreasing it at <strong>th</strong>e beginning <strong>of</strong> cooking<br />
and increasing it at <strong>th</strong>e end. In a conventional cooking, <strong>th</strong>e high bulk lignin concentration<br />
at <strong>th</strong>e end hinders diffusion <strong>of</strong> dissolved lignin out <strong>of</strong> <strong>th</strong>e chips, causing re-precipitation.<br />
The MCC process has been <strong>ac</strong>complished <strong>th</strong>rough <strong>th</strong>e modification <strong>of</strong> 2-vessel Kamyr<br />
continuous digesters to allow bo<strong>th</strong> <strong>th</strong>e introduction <strong>of</strong> white liquor at several points and<br />
counter-current flow <strong>of</strong> <strong>th</strong>e liquor during <strong>th</strong>e final cooking phase. Moreover, a<br />
nonchlorine fiber line which is used in <strong>th</strong>e mill, consists <strong>of</strong> a digester for mediumconsistency<br />
cooking and a medium consistency oxygen-delignification stage, followed by an<br />
efficient post-oxygen washing stage wi<strong>th</strong> pressure diffuser and a wash press. Kappa<br />
number reductions <strong>of</strong> 8 units for s<strong>of</strong>twood and 4 to 5 units for hardwood have been<br />
<strong>ac</strong>complished wi<strong>th</strong>out loss <strong>of</strong> streng<strong>th</strong> properties. About 20-25% less total <strong>ac</strong>tive chlorine<br />
is needed to ble<strong>ac</strong>h <strong>th</strong>e pulp to about 90% ISO brightness compared to <strong>th</strong>e conventional<br />
Kraft pulp.<br />
The MCC fiber line can be regarded as one <strong>of</strong> <strong>th</strong>e most advanced in <strong>th</strong>e world today,<br />
meeting current and future requirements for <strong>th</strong>e environment while still producing fully<br />
competitive pulp. It is possible to produce ble<strong>ac</strong>hed pulp wi<strong>th</strong>out using chlorine, <strong>ac</strong>hieving<br />
brightness even above 90% ISO, <strong>th</strong>e level required for <strong>th</strong>e most demanding market pulps.
32 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
4.3.6 DARS in soda pulping <strong>of</strong> bagasse<br />
The basic principle <strong>of</strong> <strong>th</strong>e DARS process involves <strong>th</strong>e production <strong>of</strong> sodium ferrite by<br />
auto-causticization <strong>of</strong> sodium carbonate wi<strong>th</strong> ferric oxide and subsequently to obtain<br />
sodium hydroxide by hydrolyzing <strong>th</strong>e sodium ferrite. Silica is an undesirable element in all<br />
<strong>th</strong>e spent liquors from pulping <strong>of</strong> agricultural residues. Extensive studies on <strong>th</strong>e effect <strong>of</strong><br />
silica impurity in <strong>th</strong>e recovery loop revealed <strong>th</strong>at only a minor proportion <strong>of</strong> silica passes<br />
into white liquor during ferrite auto-causticization process. This is an advantage <strong>of</strong> <strong>th</strong>e<br />
process and, unlike conventional recovery, it may not be necessary to go for additional<br />
stages <strong>of</strong> desilication <strong>of</strong> spent liquor prior to recovery operation.<br />
Among <strong>th</strong>e benefits <strong>of</strong> <strong>th</strong>e process are operational flexibility, comp<strong>ac</strong>t and simple<br />
operation, less sp<strong>ac</strong>e requirement, most economic use <strong>of</strong> fuel by way <strong>of</strong> minimized quantity<br />
<strong>of</strong> high cost fuels, non-requirement <strong>of</strong> a high degree <strong>of</strong> process automation. Unlike <strong>th</strong>e<br />
smelt in conventional recovery, <strong>th</strong>e combustion product is solid, so <strong>th</strong>e process is safe.<br />
4.3.7 Dry forming <strong>of</strong> paper web<br />
The dry forming me<strong>th</strong>od can, in principle, be divided into <strong>th</strong>e following phases: defibration<br />
<strong>of</strong> raw materials, forming, binder application, curing, and finishing.<br />
The main raw material, mostly wood pulp, is defiberized in a hammer mill. After <strong>th</strong>is, <strong>th</strong>e<br />
fibers are transported by means <strong>of</strong> a fan to <strong>th</strong>e forming section. E<strong>ac</strong>h former consists <strong>of</strong><br />
two perforated drums rotating inside <strong>th</strong>e forming head. The fibers circulate horizontally<br />
between <strong>th</strong>e drums. The <strong>ac</strong>cepted fiber material is formed onto <strong>th</strong>e moving forming wire<br />
by suction. After forming, <strong>th</strong>e web is led <strong>th</strong>rough heated comp<strong>ac</strong>tor and embosser rolls.<br />
In <strong>th</strong>e <strong>th</strong>ird phase, a binder solution is sprayed onto <strong>th</strong>e web. The application is made<br />
separately on bo<strong>th</strong> sides <strong>of</strong> <strong>th</strong>e web, e<strong>ac</strong>h application being followed by <strong>th</strong>orough-drying.<br />
<strong>Full</strong> streng<strong>th</strong> is <strong>ac</strong>hieved during <strong>th</strong>e curing as <strong>th</strong>e binder is cross-linked. The curing is also<br />
performed in a <strong>th</strong>rough-dryer. To improve <strong>th</strong>e final properties, <strong>th</strong>e web is led <strong>th</strong>rough a<br />
finishing calendar.<br />
In <strong>th</strong>e dry forming process, <strong>th</strong>e fresh water demand is only 0.8 liters per kilogram <strong>of</strong><br />
produced material (air dry). It is totally used to dilute <strong>th</strong>e binder. The dry forming process<br />
creates nei<strong>th</strong>er waste water nor effluent gases.<br />
Dry formed materials have unique absorption and wet streng<strong>th</strong> properties. They are nonabrasive,<br />
s<strong>of</strong>t, and feel like textile. The products are suitable for different kinds <strong>of</strong> toweling<br />
and wiping, in heal<strong>th</strong>-care, hygiene and for table settings. The process is non-polluting,<br />
<strong>th</strong>ere are no waste water problems, and <strong>th</strong>e mill can be located ei<strong>th</strong>er close to consumers in<br />
an urban location or near <strong>th</strong>e sources <strong>of</strong> raw materials.
Sources <strong>of</strong> Pollution and its Management in <strong>th</strong>e Pulp and Paper Industry 33<br />
4.4 Concluding Remarks on Pollution Management<br />
The most significant environmental issue is <strong>th</strong>e use <strong>of</strong> chlorine in ble<strong>ac</strong>hing. Industrial<br />
developments demonstrate <strong>th</strong>at totally chlorine-free ble<strong>ac</strong>hing is feasible for many pulp and<br />
paper products, but it cannot produce certain grades <strong>of</strong> paper. Implementation <strong>of</strong> cleaner<br />
production process and pollution prevention measures can provide bo<strong>th</strong> economic and<br />
environmental benefits. Wherever feasible, use <strong>of</strong> a total wastewater recycling system along<br />
wi<strong>th</strong> a total chlorine-free pulp ble<strong>ac</strong>hing system is, <strong>th</strong>erefore, recommended. As a<br />
minimum, total elemental chlorine-free pulp ble<strong>ac</strong>hing system may be employed.<br />
Sulfur oxide emissions are scrubbed wi<strong>th</strong> slightly alkaline solutions. Electrostatic<br />
precipitators are used to control <strong>th</strong>e release <strong>of</strong> particulate matter to <strong>th</strong>e atmosphere.<br />
Effluent treatment typically includes neutralization, primary treatment to remove<br />
suspended solids, and biological/secondary treatment to reduce BOD 5 and toxicity.<br />
Flocculation to assist in <strong>th</strong>e removal <strong>of</strong> suspended solids is also sometimes necessary.<br />
Biological treatment systems, such as <strong>ac</strong>tivated sludge and anaerobic treatment, can reduce<br />
BOD 5 by over 95 percent. Tertiary treatment may be performed to remove toxicity, color,<br />
and coliform. Solid waste treatment steps include de-watering and combustion in an<br />
incinerator, bark boiler, or a utility boiler along wi<strong>th</strong> fossil fuels. If a mechanical clarifier is<br />
used in primary treatment, <strong>th</strong>e sludge is dewatered and may be incinerated; o<strong>th</strong>erwise it is<br />
land filled.<br />
The uses <strong>of</strong> ozone for partial degradation <strong>of</strong> lignin, solvent, or dry cooking result from<br />
ano<strong>th</strong>er consideration <strong>of</strong> how to <strong>ac</strong>hieve a “clean process”. The future <strong>of</strong> <strong>th</strong>e pulp and<br />
paper industry rests wi<strong>th</strong> an objective <strong>of</strong> avoiding or reducing <strong>th</strong>e waste instead <strong>of</strong> treating<br />
it. Therefore, <strong>th</strong>e adoption <strong>of</strong> emerging clean technologies along wi<strong>th</strong> <strong>th</strong>e computerization<br />
<strong>of</strong> processes will guarantee a cleaner and highly energy efficient pulp and paper industry in<br />
<strong>th</strong>e future.
34 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
5. CROSS COUNTRY REPORT ON THE PULP AND PAPER INDUSTRY<br />
5.1 Introduction<br />
The pulp and paper industry has been growing very rapidly in <strong>th</strong>e developing countries. As an<br />
essential commodity for <strong>th</strong>e society and <strong>th</strong>e consumption <strong>of</strong> paper being normally parallel wi<strong>th</strong> <strong>th</strong>e<br />
economic grow<strong>th</strong> <strong>of</strong> a particular country, <strong>th</strong>e production <strong>of</strong> paper products are expected to increase<br />
in <strong>th</strong>e future, especially in <strong>th</strong>e developing countries. The pulp and paper industry is capital, energy<br />
and pollution intensive; however, <strong>th</strong>e pr<strong>of</strong>its from <strong>th</strong>is industry are usually marginal. Therefore,<br />
many developing countries have avoided investment risks and have been importing <strong>th</strong>e pulp and<br />
high quality paper products. Along wi<strong>th</strong> <strong>th</strong>e rapid industrialization, <strong>th</strong>e developing countries have<br />
been trying to increase <strong>th</strong>eir domestic productions to meet <strong>th</strong>e higher share <strong>of</strong> national demands.<br />
Considering <strong>th</strong>e competitiveness wi<strong>th</strong> <strong>th</strong>e outside world, <strong>th</strong>e energy consumption which is one <strong>of</strong><br />
<strong>th</strong>e major inputs to <strong>th</strong>e pulp and paper industry has become an important issue in <strong>th</strong>e developing<br />
countries.<br />
This section presents a comparative study <strong>of</strong> <strong>th</strong>e pulp and paper industries <strong>of</strong> China, India, <strong>th</strong>e<br />
Philippines and Sri Lanka. The production trends and <strong>th</strong>e role <strong>of</strong> <strong>th</strong>e industry are presented for e<strong>ac</strong>h<br />
country. A comparison has been done in order to understand <strong>th</strong>e major causes <strong>of</strong> inefficiency in<br />
energy use and pollution abatement in <strong>th</strong>e industry. The possible improvements are identified and<br />
<strong>th</strong>e potential for <strong>th</strong>e introduction <strong>of</strong> energy efficient and environmentally sound technologies is<br />
assessed.<br />
5.2 Overview <strong>of</strong> <strong>th</strong>e industry<br />
To have an overview <strong>of</strong> <strong>th</strong>e pulp and paper industries <strong>of</strong> <strong>th</strong>e countries under study, comparisons<br />
have been made on <strong>th</strong>e role <strong>of</strong> <strong>th</strong>e industry in e<strong>ac</strong>h country, shares in industrial and total national<br />
energy consumption, production trends and number <strong>of</strong> mills and <strong>th</strong>eir cap<strong>ac</strong>ities.<br />
5.2.1 Role in <strong>th</strong>e national economy<br />
In 1993, <strong>th</strong>e Chinese pulp and paper industry <strong>ac</strong>counted for 1.54% <strong>of</strong> <strong>th</strong>e total industrial sector’s<br />
gross output value.<br />
5.2.2 Share in total energy consumption<br />
In China, <strong>th</strong>e pulp and paper industry is <strong>th</strong>e largest energy consumer among all light industries. In<br />
1992, <strong>th</strong>e energy consumption <strong>of</strong> Chinese pulp and paper industry <strong>ac</strong>counted for 3.25% and 1.74%<br />
<strong>of</strong> total industrial and national energy consumptions, respectively.<br />
In India, <strong>th</strong>e pulp and paper industry is ranked as <strong>th</strong>e six<strong>th</strong> largest energy consumer in <strong>th</strong>e country.
Cross Country Comparison <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry35<br />
In 1992, <strong>th</strong>e Philippines’ pulp and paper industry <strong>ac</strong>counted for 8.45% <strong>of</strong> industrial sector’s energy<br />
consumption and 2.5% <strong>of</strong> total national energy consumption.<br />
5.2.3 Production trends<br />
Among <strong>th</strong>e countries under <strong>th</strong>is study, China ranked as <strong>th</strong>e world’s <strong>th</strong>ird largest paper and paper<br />
board producer in 1992 after USA and Japan. The trends <strong>of</strong> pulp and paper and paper board<br />
productions are shown in Figure 5.1.<br />
Million Tons<br />
Thousand Tons<br />
12<br />
10<br />
8<br />
6<br />
4<br />
2<br />
0<br />
500<br />
400<br />
300<br />
200<br />
100<br />
Pulp Production<br />
1980 1985 1990 1992<br />
China<br />
India<br />
Philippines' Paper & Paper Board Production<br />
0<br />
1980 1981 1982 1983 1984 1985 1986 1987 1988<br />
Million Tons<br />
Thousand Tons<br />
14<br />
12<br />
10<br />
8<br />
6<br />
4<br />
2<br />
0<br />
30<br />
25<br />
20<br />
15<br />
10<br />
5<br />
0<br />
China<br />
India<br />
Paper & Paper Board Production<br />
1980 1985 1990 1992<br />
Sri Lankan Pulp and Paper & Paper Board Production<br />
Pulp<br />
Paper Products<br />
1980 1990 1992<br />
Figure 5.1 Production trends <strong>of</strong> pulp, paper & paper board<br />
The pulp and paper industry is growing very rapidly in China wi<strong>th</strong> an average grow<strong>th</strong> rate in paper<br />
and paper board production <strong>of</strong> about 14% in <strong>th</strong>e last decade, <strong>th</strong>e highest value in <strong>th</strong>e world.<br />
However, China is still importing pulp and paper products to meet <strong>th</strong>e national demand. In 1992,<br />
net imported paper and paper board was 2.34 million tons and commercial pulp was 0.6 million<br />
tons. Wi<strong>th</strong> low per capita consumption <strong>of</strong> 16.7 kg per year (world average per capital consumption is<br />
45.3 kg per year), <strong>th</strong>e demand and production <strong>of</strong> paper products are expected to increase in China.
36 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
From Figure 5.1, it can be seen <strong>th</strong>at Indian pulp and paper and paper board production had a<br />
significant increase in <strong>th</strong>e last decade. The pulp production remained nearly constant from 1990 to<br />
1992 while <strong>th</strong>e paper products had been increasing along wi<strong>th</strong> <strong>th</strong>e increase in imported commercial<br />
pulp.<br />
In Philippines, <strong>th</strong>e production <strong>of</strong> paper and paper board was greatly fluctuating in <strong>th</strong>e last decade<br />
and has been <strong>ac</strong>hieving significant grow<strong>th</strong> since 1985. Sri Lankan paper industry has become more<br />
dependent on <strong>th</strong>e imported commercial pulp.<br />
5.2.4 Mills and <strong>th</strong>eir cap<strong>ac</strong>ities<br />
The average plant cap<strong>ac</strong>ity <strong>of</strong> <strong>th</strong>e pulp and paper industries in <strong>th</strong>e countries under study are shown<br />
in Figure 5.2.<br />
'000 Tons per year<br />
30<br />
25<br />
20<br />
15<br />
10<br />
5<br />
0<br />
2.5<br />
10.166<br />
China India Philippines Sri Lanka<br />
Figure 5.2 Average plant cap<strong>ac</strong>ity (paper and paper board production)<br />
At <strong>th</strong>e end <strong>of</strong> 1992, <strong>th</strong>ere were 11,940 enterprises in Chinese pulp and paper industry. The pulp and<br />
paper board cap<strong>ac</strong>ity <strong>of</strong> <strong>th</strong>e biggest mill is 150,000 tons per year. The breakdown <strong>of</strong> <strong>th</strong>e Chinese mill<br />
by annual plant cap<strong>ac</strong>ity is given in Figure 5.3. Therefore, <strong>th</strong>e small mills dominate in China,<br />
contributing to about 57% <strong>of</strong> <strong>th</strong>e total production.<br />
In India, <strong>th</strong>ere are 325 mills, 26 integrated mills and 297 small paper mills in <strong>th</strong>e pulp and paper<br />
industry. The number <strong>of</strong> small mills has been increasing more rapidly <strong>th</strong>an <strong>th</strong>e large mills so <strong>th</strong>at<br />
average plant cap<strong>ac</strong>ity has decreased from 12,222 tons <strong>of</strong> paper products in 1980 to 10,166 tons in<br />
1992. Wi<strong>th</strong> <strong>th</strong>e increasing paper demand and shortage <strong>of</strong> forest based raw material, <strong>th</strong>e Government<br />
<strong>of</strong> India has formulated a policy <strong>of</strong> promoting small mills based on straw and bagasse.<br />
15<br />
25.5
Cross Country Comparison <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry37<br />
88%<br />
>30,000 10,000-30,000
38 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
5.3 Char<strong>ac</strong>teristics <strong>of</strong> <strong>th</strong>e Parameters Affecting Energy Efficiency<br />
The specific energy consumption <strong>of</strong> <strong>th</strong>e pulp and paper industry depends on <strong>th</strong>e following:<br />
- Raw material mix<br />
- Share <strong>of</strong> imported pulp<br />
- Pulping process mix<br />
- Share <strong>of</strong> waste-paper pulp<br />
- Level <strong>of</strong> bl<strong>ac</strong>k liquor recovery<br />
- Share <strong>of</strong> cogenerated electricity<br />
- Product mix, etc.<br />
The overall specific energy consumption <strong>of</strong> <strong>th</strong>e pulp and paper industries <strong>of</strong> <strong>th</strong>e selected countries<br />
and world average are given in Figure 5.5.<br />
GJ/Ton <strong>of</strong> Paper Products<br />
80<br />
70<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
China India Philippines Japan World<br />
Average<br />
Figure 5.5 Specific energy consumption <strong>of</strong> <strong>th</strong>e pulp and paper industry<br />
It can be seen <strong>th</strong>at <strong>th</strong>e specific energy consumption <strong>of</strong> Indian pulp and paper industry is significantly<br />
too high. In comparison wi<strong>th</strong> Japan, <strong>th</strong>e Chinese pulp and paper industry consumes more <strong>th</strong>an<br />
double <strong>th</strong>e energy to produce <strong>th</strong>e same amount <strong>of</strong> paper products. The low specific energy<br />
consumption <strong>of</strong> <strong>th</strong>e industry in <strong>th</strong>e Philippines is due to <strong>th</strong>e high share <strong>of</strong> imported pulp. The trends<br />
<strong>of</strong> specific energy consumption in China and India are given in Figure 5.6.<br />
One can observe a gradual reduction <strong>of</strong> specific energy consumption <strong>of</strong> <strong>th</strong>e order <strong>of</strong> 5.33% in China<br />
in <strong>th</strong>e last decade. However, <strong>th</strong>e specific energy consumption <strong>of</strong> Indian pulp and paper industry did<br />
not reduce significantly in <strong>th</strong>e last decade; it has only started decreasing since 1990.<br />
In order to understand <strong>th</strong>e major causes <strong>of</strong> <strong>th</strong>e inefficiency in energy use, some parameters affecting<br />
<strong>th</strong>e energy efficiency are compared in <strong>th</strong>is section.
Cross Country Comparison <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry39<br />
GJ/Ton <strong>of</strong> Paper Products<br />
90<br />
80<br />
70<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
China<br />
India<br />
1980 1981 1984 1985 1990 1992<br />
Figure 5.6 Trends <strong>of</strong> specific energy consumption in China and India<br />
5.3.1 Raw material mix<br />
The major difference between <strong>th</strong>e developing countries and <strong>th</strong>e industrialized countries in raw<br />
material mix is <strong>th</strong>e share <strong>of</strong> wood pulp in paper making. The share <strong>of</strong> wood pulp in national total is<br />
given in Figure 5.7. The higher <strong>th</strong>e share <strong>of</strong> wood pulp, <strong>th</strong>e lower is <strong>th</strong>e overall specific energy<br />
consumption <strong>of</strong> <strong>th</strong>e pulp and paper industry.<br />
In China, straw-material-made pulp holds a dominant share in <strong>th</strong>e mix, <strong>ac</strong>counting for 63% <strong>of</strong> <strong>th</strong>e<br />
total pulp. In India, bamboo pulp <strong>ac</strong>counted for 43.42% and bagasse and straw pulp toge<strong>th</strong>er had a<br />
share <strong>of</strong> 33.38% <strong>of</strong> <strong>th</strong>e total pulp produced.<br />
5.3.2 Level <strong>of</strong> waste paper utilization<br />
Greater level <strong>of</strong> waste paper utilization in pulping leads to resources conservation, energy saving and<br />
environmental protection. Developing countries however tend to use lower percentage <strong>of</strong> waste<br />
paper in comparison wi<strong>th</strong> <strong>th</strong>e developed countries. The level <strong>of</strong> waste paper utilization is shown in<br />
Figure 5.8 for selected countries. This is found to be quite low in China and India, leading to <strong>th</strong>e<br />
higher specific energy consumption <strong>of</strong> <strong>th</strong>e industry.<br />
5.3.3 Energy consumption by type<br />
The breakdown <strong>of</strong> specific energy consumption by type is given in Table 5.1. The major steam<br />
consumers in <strong>th</strong>e pulp and paper industry are digesters and dryers. It can be seen in <strong>th</strong>is table <strong>th</strong>at<br />
<strong>th</strong>e specific steam consumption <strong>of</strong> Indian pulp and paper mills is too high, reflecting <strong>th</strong>e inefficiency<br />
<strong>of</strong> digesters and dryers. The higher steam consumption in digesters is due to <strong>th</strong>e non-wood pulping.<br />
The high electricity consumption can be reduced by repl<strong>ac</strong>ing/modifying outdated paper-making<br />
m<strong>ac</strong>hines which are <strong>th</strong>e major electricity consumers.
40 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
% <strong>of</strong> Total Pulp<br />
100<br />
80<br />
60<br />
40<br />
20<br />
0<br />
23.9 23.2<br />
47.63<br />
23.03<br />
95.1<br />
99.3 99.1<br />
China India Philippines Sri Lanka Japan US France<br />
Figure 5.7 Share <strong>of</strong> wood pulp in selected countries<br />
% <strong>of</strong> Total Pulp<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
22.5<br />
29<br />
51.2<br />
52.57<br />
China Philippines Japan<br />
* % <strong>of</strong> total installed cap<strong>ac</strong>ity<br />
Figure 5.8 Level <strong>of</strong> waste paper utilization<br />
Table 5.1 Specific energy consumption by type<br />
China India Philippines Developed<br />
Countries<br />
Steam Consumption (Tons/ton paper) N/A 10-16 6-7 4-6.5<br />
Electricity Consumption (kWh/ton Paper) 1100-1800 1200-1700 1000-1100 500-1100<br />
5.3.4<br />
5.3.5 Awareness about energy conservation<br />
Wi<strong>th</strong> increasing energy cost and international competitiveness, some energy conservation measures<br />
<strong>th</strong>at have been undertaken in <strong>th</strong>e selected countries are summarized in Table 5.2.<br />
50<br />
48
Cross Country Comparison <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry41<br />
Table 5.2 Energy conservation measures undertaken in different countries<br />
Country Energy Conservation Measures<br />
China - Holding energy management training workshops<br />
- Improving efficiency <strong>of</strong> boilers and condensate recovery<br />
- Enhancing <strong>th</strong>ermal insulation performance<br />
- Popularizing energy saving electrical appliances<br />
- Increasing level <strong>of</strong> chemicals recovery<br />
- Conversion <strong>of</strong> cylindrical to Fourdrinier paper m<strong>ac</strong>hines<br />
- Conversion <strong>of</strong> batch to continuous digesters<br />
- Installation <strong>of</strong> on-line moisture monitoring and control systems<br />
- Installation <strong>of</strong> efficient press<br />
- Installation <strong>of</strong> jump-pro<strong>of</strong> energy-saving pumps<br />
- Employment <strong>of</strong> heat pump in dryer section<br />
- Enhancing bl<strong>ac</strong>k liquor recovery<br />
- Installation <strong>of</strong> computer-controlled cooking<br />
- Pr<strong>ac</strong>ticing cogeneration<br />
India - Installation <strong>of</strong> condensate recovery systems<br />
- Conversion <strong>of</strong> batch to continuous digesters<br />
- Conversion <strong>of</strong> cylindrical to Fourdrinier paper m<strong>ac</strong>hines<br />
- Enhancing chemical recovery<br />
- Installation <strong>of</strong> falling film type evaporators<br />
- Employing process automation<br />
- Repl<strong>ac</strong>ement <strong>of</strong> disc chippers by drum chippers<br />
- Conversion <strong>of</strong> pneumatic conveyors to mechanical types<br />
- Conversion <strong>of</strong> spreader stoker to fluidized bed combustion boilers<br />
Philippines - Installation <strong>of</strong> computerized moisture control system<br />
- Taking energy audits<br />
- Installation <strong>of</strong> cogeneration systems<br />
- Power f<strong>ac</strong>tor improvements<br />
Therefore, it can be seen <strong>th</strong>at some advanced energy efficient technologies have been already<br />
installed in <strong>th</strong>e developing countries. However, <strong>th</strong>e dissemination rate <strong>of</strong> <strong>th</strong>ese technologies is very<br />
limited in comparison wi<strong>th</strong> <strong>th</strong>e industrialized countries.<br />
5.4 Char<strong>ac</strong>teristics <strong>of</strong> <strong>th</strong>e parameters affecting pollution abatement measures<br />
There is great potential for resources recovery in <strong>th</strong>is industry <strong>th</strong>rough pollution abatement<br />
measures. But less attention was paid in <strong>th</strong>is direction mainly due to limited dissemination <strong>of</strong> <strong>th</strong>ose<br />
technologies and high capital share for <strong>th</strong>e industry which is categorized as small scale in <strong>th</strong>ese<br />
developing countries. However, some local environmental regulations and public awareness due to<br />
growing industrialization in <strong>th</strong>e region has forced <strong>th</strong>e industries to introduce some pollution
42 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
abatement programs. The obsolete m<strong>ac</strong>hinery and technologies generally in use in <strong>th</strong>is region fur<strong>th</strong>er<br />
weaken <strong>th</strong>e already deteriorated environment. The type and quantity <strong>of</strong> pollutants produced vary<br />
from industry to industry depending on <strong>th</strong>e process employed.<br />
5.4.1 Causes <strong>of</strong> pollution<br />
The causes <strong>of</strong> pollution from pulp and paper industries in <strong>th</strong>e countries studied are attributed to <strong>th</strong>e<br />
following:<br />
- Type <strong>of</strong> raw material in use (predominantly agro-residue based industry)<br />
- Type <strong>of</strong> fuel in use to meet energy demand<br />
- Obsolete technology and m<strong>ac</strong>hinery in use<br />
- Lower production cap<strong>ac</strong>ities <strong>of</strong> <strong>th</strong>e mills, using inferior technical equipment<br />
- No strict enforcement <strong>of</strong> environmental regulations<br />
- <strong>th</strong>inking <strong>th</strong>at it is an extra expenditure wi<strong>th</strong>out any return<br />
- A marginal pr<strong>of</strong>it making industry<br />
As shown in <strong>th</strong>e Figure 5.7, <strong>th</strong>e share <strong>of</strong> wood pulp in <strong>th</strong>e countries under study is about one four<strong>th</strong><br />
<strong>of</strong> <strong>th</strong>e production except in <strong>th</strong>e Philippines where it is nearly 50%. But in developed countries <strong>th</strong>e<br />
share is almost 100% which implies <strong>th</strong>at more research and development are under way to eliminate<br />
pollution problem by wood pulping. The agro-residue based raw materials cause more pollution<br />
problems <strong>th</strong>an <strong>th</strong>e wood. In India, China and Sri Lanka straw dominates <strong>th</strong>e share <strong>of</strong> <strong>th</strong>e raw<br />
material for pulping. Among all <strong>th</strong>e non-woody raw materials, straw poses <strong>th</strong>e most serious<br />
environmental pollution problem because <strong>of</strong> <strong>th</strong>e difficulties in chemical recovery from bl<strong>ac</strong>k liquor<br />
due to its high silica content. The use <strong>of</strong> waste paper as raw material reduces bo<strong>th</strong> energy<br />
consumption and pollution problems. As seen in Figure 5.8 <strong>th</strong>e utilization levels <strong>of</strong> waste paper in<br />
Sri Lanka and Philippines are <strong>th</strong>e same as <strong>th</strong>e industrialized countries (about 50% <strong>of</strong> <strong>th</strong>e pulp<br />
production), whereas it is only 25% <strong>of</strong> total pulp production in India and China.<br />
5.4.2 Current water pollution control strategies<br />
As pulp and paper is a serious water polluting industry, some measures are under way to abate<br />
pollution problems whose potential for improvements is very high. Current pr<strong>ac</strong>tices to abate water<br />
pollution in <strong>th</strong>ese countries are reported as below.<br />
5.4.2.1 In China<br />
During <strong>th</strong>e period <strong>of</strong> 1980 to 1988<br />
- BOD discharge decreased by 33%<br />
- Suspended solids decreased by 36%<br />
- Alkali recovery increase at <strong>th</strong>e rate <strong>of</strong> 5.3%<br />
These reductions were <strong>ac</strong>hieved by<br />
- Integrated exploitation <strong>of</strong> digested wastewater
Cross Country Comparison <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry43<br />
- White water recycling<br />
- Fiber recovery<br />
- Alkali recovery<br />
However <strong>th</strong>ose developments are mainly reported for <strong>th</strong>e large and medium scale pulp and paper<br />
industries. In 1990, alkali recovery rate in <strong>th</strong>e wood pulp mills is reported as more <strong>th</strong>an 60% whereas<br />
<strong>th</strong>e recovery rate in straw pulp mill is around 6%. This should be mainly because <strong>of</strong> <strong>th</strong>e high silica<br />
content in <strong>th</strong>e bl<strong>ac</strong>k liquor <strong>of</strong> rice straw for which <strong>th</strong>ere have been limited technological<br />
developments.<br />
In 1989 - 1990:<br />
- 13% <strong>of</strong> <strong>th</strong>e total discharged wastewater met <strong>th</strong>e local regulatory standards<br />
- for <strong>th</strong>e first time a regulation was set up for wastewater disposal<br />
- no regulation related to air pollution existed<br />
- average alkali recovery percentage 34%<br />
- average alkali recovery rate in large scale enterprise was 80 -90%<br />
- average alkali recovery rate in medium scale enterprise was 75 - 80%<br />
- wastewater treated and recycling ratio was 30 - 50%<br />
5.4.2.2 In India<br />
- small mills generate more pollutants due to <strong>th</strong>e absence <strong>of</strong> chemical recovery system<br />
- Production process control to reduce wastewater volume and pollutants<br />
- Wastewater treatment technologies to reduce <strong>th</strong>e pollution streng<strong>th</strong><br />
- Use <strong>of</strong> oxygen and peroxide as ble<strong>ac</strong>hing agents<br />
- Chemical recovery<br />
During <strong>th</strong>e period <strong>of</strong> 1985 to 1993<br />
- Alkali recovery per year increased from 285,000 to 455,000 tons<br />
- Wastewater treated and recycled per year increased from 1520 to 520 million m 3<br />
- Material recovery and recycling per year increased from 1,520,000 to 2,550,000 tons<br />
5.4.2.3 In Philippines<br />
- Most <strong>of</strong> <strong>th</strong>e old mills only have filters for fiber recovery<br />
- Chemical recovery is pr<strong>ac</strong>ticed to certain extent<br />
In Sri Lanka, <strong>of</strong> <strong>th</strong>e only two pulp and paper mills, one has no chemical recovery f<strong>ac</strong>ilities. Though<br />
<strong>th</strong>e second plant has <strong>th</strong>e f<strong>ac</strong>ility, it was never commissioned because <strong>of</strong> <strong>th</strong>e higher silica content in<br />
<strong>th</strong>e bl<strong>ac</strong>k liquor. As a remedial measure, raw material for pulping was changed to waste paper from<br />
rice straw.
44 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
5.4.3 Current air pollution control strategies<br />
The major sources <strong>of</strong> air pollution are burning <strong>of</strong> fuels for power generation and dedusting <strong>of</strong> raw<br />
materials. Since air pollution in <strong>th</strong>is industry is not serious as water pollution, much less attention is<br />
paid in <strong>th</strong>is area. To give an example, no air emission regulations were en<strong>ac</strong>ted in China until 1990.<br />
But in India, <strong>th</strong>e air pollution <strong>ac</strong>t was en<strong>ac</strong>ted in 1981; cyclones and Electrostatic precipitators are<br />
mainly used as air pollution control equipment whose share <strong>of</strong> 20% in 1960 increased to 60% in<br />
1992.<br />
5.4.4 Current solid waste control strategies<br />
In all <strong>th</strong>ese countries, solid wastes generated from <strong>th</strong>e process itself and secondary wastes derived<br />
from pollution control measures such as dust collection equipment and wastewater treatment, are<br />
dumped at landfill sites wi<strong>th</strong>out any pretreatment. In some plants <strong>th</strong>e solid waste which can be used<br />
as fuel is recycled to repl<strong>ac</strong>e <strong>th</strong>e boiler fuels.<br />
5.4.5 Comparison <strong>of</strong> effluent and emission char<strong>ac</strong>teristics<br />
In general, <strong>th</strong>e information provided in <strong>th</strong>e country reports are quite diverse and use different basis.<br />
As some <strong>of</strong> <strong>th</strong>em are given for per ton production basis whereas o<strong>th</strong>ers in ambient standards, it is<br />
not possible to make any comparison in some cases. For <strong>th</strong>e purpose <strong>of</strong> comparison it is preferable<br />
to have <strong>th</strong>e amount <strong>of</strong> pollutant released per ton <strong>of</strong> product <strong>th</strong>an in ambient standards. It is mainly<br />
because <strong>th</strong>e allowable limit <strong>of</strong> pollutant discharge to <strong>th</strong>e surrounding in different countries depends<br />
on <strong>th</strong>e geographical location, climatic condition and overall intensity <strong>of</strong> pollutants released from all<br />
o<strong>th</strong>er sources.<br />
A comparison <strong>of</strong> fresh water consumption, quantity and char<strong>ac</strong>teristics <strong>of</strong> wastewater wi<strong>th</strong> German<br />
standards is presented in Table 5.3. Even <strong>th</strong>ough a number <strong>of</strong> parameters are tabulated, most <strong>of</strong><br />
<strong>th</strong>em cannot be compared due to <strong>th</strong>e limitation <strong>of</strong> data availability. Also, as seen from Table 5.3, no<br />
data are available for <strong>th</strong>e Philippines and Sri Lanka, may be due to <strong>th</strong>e minor share <strong>of</strong> <strong>th</strong>ese<br />
industries in <strong>th</strong>eir national economy.<br />
A similar comparison for air emission are shown in Table 5.4. As said earlier <strong>th</strong>e comparison was<br />
not possible in most <strong>of</strong> <strong>th</strong>e cases because <strong>of</strong> non-availability <strong>of</strong> data from any <strong>of</strong> <strong>th</strong>e countries under<br />
study. It implies <strong>th</strong>at none <strong>of</strong> <strong>th</strong>e countries pays any attention to air pollution abatement.
Cross Country Comparison <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry45<br />
Table 5.3 Quantity and char<strong>ac</strong>teristics <strong>of</strong> wastewater released<br />
Parameters<br />
Water consumption<br />
Germany * China India Philippine<br />
s<br />
Sri Lanka<br />
(ton/ton ble<strong>ac</strong>hed pulp produced) 70 - 130<br />
(ton/ton paper produced)<br />
Wastewater discharged<br />
220 30<br />
(ton/ton ble<strong>ac</strong>hed pulp produced) 7 - 12<br />
(ton/ton paper produced)<br />
PH<br />
70-380**<br />
Suspended solids (mg/l)<br />
Settleable solids (ml/l)<br />
DS (mg/l)<br />
50 151*** 10***<br />
BOD5 (kg/ton pulp)<br />
5<br />
10-270<br />
(kg/ton paper)<br />
1-6<br />
COD (kg/ton pulp)<br />
70<br />
50-1100**<br />
(kg/ton paper)<br />
Oil and Grease (mg/l)<br />
Total N (mg/l)<br />
3-12 150<br />
5<br />
Wastewater reuse rate (%)<br />
Treatment rate <strong>of</strong> wastewater (%)<br />
Proportion re<strong>ac</strong>hing discharge<br />
standards (%)<br />
68.6 90-95<br />
Hydro carbons (kg/ton pulp) 1.0<br />
(kg/ton paper) 0.01-0.04<br />
* The German regulatory standard; BOD & COD based on 24 hour sample<br />
** Depending on <strong>th</strong>e raw material; waste paper lowest & rice straw etc. high<br />
*** in kg/ton paper<br />
Table 5.4 Quantity and char<strong>ac</strong>teristics <strong>of</strong> air pollutants released<br />
Parameters German China* Indi Philippine<br />
y<br />
a s<br />
Dust discharged (TSP) (mg/m3) 30 260,000<br />
SO2 (mg/m3) 100 270,000<br />
NOx (mg/m3) 500<br />
CO (mg/m3) Organics (mg/m<br />
100<br />
3)<br />
Treatment rate <strong>of</strong> waste gas (%)<br />
Rate <strong>of</strong> treated waste gas discharged<br />
which meet standards (%)<br />
* in tons<br />
Sri<br />
Lanka
46 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
5.5 Potential for Energy Efficiency Improvement<br />
5.5.1 Structure <strong>of</strong> <strong>th</strong>e industry<br />
One <strong>of</strong> <strong>th</strong>e major reasons for <strong>th</strong>e high specific energy consumption in China and India is <strong>th</strong>e small<br />
scale <strong>of</strong> <strong>th</strong>e mills. Taking m<strong>ac</strong>ro economic consideration into <strong>ac</strong>count, <strong>th</strong>e expansion <strong>of</strong> small mills<br />
based on non-wood materials might be suitable for some countries. In such a case, <strong>th</strong>e expansion <strong>of</strong><br />
small mills should be planned ensuring <strong>th</strong>at <strong>th</strong>ey incorporate energy efficient technologies and<br />
chemical recovery systems.<br />
In <strong>th</strong>e case <strong>of</strong> India, <strong>th</strong>e capital utilization f<strong>ac</strong>tor is too low, <strong>th</strong>erefore, closure <strong>of</strong> inefficient small<br />
mills would improve <strong>th</strong>e overall energy efficiency <strong>of</strong> <strong>th</strong>e industry.<br />
Finally, <strong>th</strong>e future expansion <strong>of</strong> <strong>th</strong>e industry should be based on <strong>th</strong>e large-scale mills so <strong>th</strong>at<br />
cogeneration f<strong>ac</strong>ilities and <strong>th</strong>ermal upgrading systems can be employed economically.<br />
5.5.2 Raw materials<br />
The specific energy consumption <strong>of</strong> <strong>th</strong>e pulp and paper industry can be reduced by increasing <strong>th</strong>e<br />
share <strong>of</strong> wood pulp. However, <strong>th</strong>is is a question <strong>of</strong> m<strong>ac</strong>ro economics and <strong>th</strong>e concern for <strong>th</strong>e<br />
preservation <strong>of</strong> forest resources. The current level <strong>of</strong> waste paper recycling in <strong>th</strong>e developing<br />
countries is lower <strong>th</strong>an <strong>th</strong>at in industrialized countries. Therefore, increasing <strong>th</strong>e share <strong>of</strong> recycled<br />
paper could improve <strong>th</strong>e overall energy efficiency <strong>of</strong> <strong>th</strong>e industry.<br />
5.5.3 Potential for energy conservation<br />
The potential for major energy conservation in <strong>th</strong>e countries under <strong>th</strong>is study is summarized in<br />
Table 5.5.<br />
5.6 Potential for pollution abatement<br />
Use <strong>of</strong> non-wood raw materials are identified as one <strong>of</strong> <strong>th</strong>e major source <strong>of</strong> pollutant in <strong>th</strong>is region.<br />
Due to <strong>th</strong>e economic level and availability <strong>of</strong> non-wood raw material in plenty, it is impossible to<br />
eliminate its use. Since in developed countries wood covers almost all <strong>th</strong>e raw material requirements,<br />
<strong>th</strong>e developing countries which use non-wood products as raw material must have <strong>th</strong>eir own<br />
research and development f<strong>ac</strong>ilities to develop environmentally sound technologies. As a serious<br />
water polluting industry, its future expansion in <strong>th</strong>is region should be well planned to abate pollution<br />
load on <strong>th</strong>e environment. As seen earlier, <strong>th</strong>e pollution abatement measures in <strong>th</strong>ese countries are in<br />
<strong>th</strong>eir infancy. So as a first step, records should be maintained about pollution loads and water<br />
consumption.
Cross Country Comparison <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry47<br />
Table 5.5 Potential for energy conservation #<br />
Energy Conservation Measures China India Philippines Sri<br />
Lanka<br />
Short Term Measures<br />
- Management pr<strong>ac</strong>tices<br />
- Boiler efficiency improvement<br />
- Insulation improvement<br />
- Power f<strong>ac</strong>tor improvement<br />
Medium Term Measures<br />
- Chemical recovery<br />
- Condensate recovery<br />
- Cogeneration<br />
- Me<strong>th</strong>anogenesis<br />
- Conversion <strong>of</strong> batch to continuous digesters<br />
- Mechanical vapor compression <strong>of</strong> bl<strong>ac</strong>k<br />
liquor<br />
- V<strong>ac</strong>uum pump installation<br />
- Installation <strong>of</strong> efficient press<br />
- Heat pump hot water system<br />
- Flash steam recovery in dryers<br />
- Process automation<br />
Long Term Measures<br />
- Interconnected f<strong>ac</strong>tories (wi<strong>th</strong> sugar mills)<br />
- Excess power generation<br />
- Adaptation <strong>of</strong> new pulping processes<br />
- Computerization<br />
**<br />
**** 1<br />
***<br />
***<br />
*** 3<br />
***<br />
*** 5<br />
****<br />
****<br />
****<br />
****<br />
**** 7<br />
****<br />
****<br />
****<br />
***<br />
****<br />
****<br />
****<br />
****<br />
*** 2<br />
****<br />
****<br />
**** 4<br />
****<br />
**** 6<br />
****<br />
****<br />
****<br />
****<br />
**** 8<br />
****<br />
****<br />
*** 9<br />
****<br />
****<br />
****<br />
****<br />
****<br />
***<br />
****<br />
***<br />
***<br />
****<br />
****<br />
****<br />
***<br />
***<br />
****<br />
****<br />
****<br />
****<br />
****<br />
**<br />
****<br />
***<br />
****<br />
# For e<strong>ac</strong>h energy conservation measure, <strong>th</strong>e relative scope <strong>of</strong> application is shown by <strong>th</strong>e number <strong>of</strong><br />
asterisks. For instance, <strong>th</strong>e measure <strong>of</strong> connecting wi<strong>th</strong> sugar mills has a higher scope in India, where <strong>th</strong>e<br />
share <strong>of</strong> bagasse-pulp is significant, <strong>th</strong>an in China where straw-pulp is more important.<br />
****<br />
***<br />
***<br />
***<br />
***<br />
***<br />
***<br />
****<br />
***<br />
***<br />
****<br />
****<br />
****<br />
****<br />
****<br />
-<br />
****<br />
***<br />
****<br />
1 Most <strong>of</strong> <strong>th</strong>e Chinese mills have boiler efficiencies below 60%<br />
2 Boiler efficiency in small mills is 50-60%, however, most <strong>of</strong> <strong>th</strong>e medium and large mills<br />
employ fluidized boilers wi<strong>th</strong> an efficiency <strong>of</strong> 70-80%<br />
3 Alkali recovery rate in China was 36.66% <strong>of</strong> total consumption in 1988<br />
4 Nearly all agro-based paper mills have no chemical recovery system<br />
5 Almost all mills have cogeneration systems but <strong>th</strong>ey could meet only 10.5% <strong>of</strong> electricity<br />
demand<br />
6 Only 40% <strong>of</strong> Indian large mills have cogeneration f<strong>ac</strong>ilities<br />
7 Dryness <strong>of</strong> wet paper from paper m<strong>ac</strong>hine is about 30% in China<br />
8 Dryness <strong>of</strong> wet paper from paper m<strong>ac</strong>hine is 35-38% (50% in developed countries)<br />
9 About 25% <strong>of</strong> Indian mills have installed electronic automation systems
48 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
The source reduction and waste minimization measures ra<strong>th</strong>er <strong>th</strong>an end <strong>of</strong> pipe treatment not only<br />
lead to cost saving in waste treatment but also save <strong>th</strong>e depleting natural resources. Recovering and<br />
recycling <strong>of</strong> fibers seems to be <strong>th</strong>e most promising <strong>of</strong> all <strong>th</strong>e measures. Larger <strong>th</strong>e mill, lesser is <strong>th</strong>e<br />
specific treatment cost, bo<strong>th</strong> in terms <strong>of</strong> capital as well as operation and maintenance costs. But due<br />
to <strong>th</strong>e nature <strong>of</strong> <strong>th</strong>e industry and availability <strong>of</strong> raw materials, it is difficult to control <strong>th</strong>e grow<strong>th</strong> <strong>of</strong><br />
<strong>th</strong>e small scale industries in <strong>th</strong>is region. Therefore, <strong>th</strong>e optimum level <strong>of</strong> mill cap<strong>ac</strong>ity should be<br />
estimated on <strong>th</strong>e basis <strong>of</strong> various considerations to plan <strong>th</strong>e future expansion <strong>of</strong> <strong>th</strong>e industry.<br />
The potentials for major pollution abatement options based on <strong>th</strong>e available technologies are<br />
summarized in <strong>th</strong>e Table 5.6.<br />
Table 5.6 Potentials for pollution abatement measures #<br />
Pollution Abatement Measures China India Philippines Sri Lanka<br />
Short Term Measures<br />
- Management pr<strong>ac</strong>tices<br />
- Good house keeping<br />
- Operating at optimized parameters<br />
- <strong>Full</strong> cap<strong>ac</strong>ity utilization<br />
- Prevention <strong>of</strong> leakage, spills, overflows et.<br />
- Resource recovery and recycling<br />
- Improving water recycle utilization ratio (e.g. white<br />
water recycling for washing <strong>of</strong> pulp)<br />
- Implementation <strong>of</strong> environmental regulations<br />
strictly<br />
Medium Term Measures<br />
- Improved chemical recovery<br />
- Substitution for Chlorine wi<strong>th</strong> ozone, oxygen and<br />
hydrogen peroxide in ble<strong>ac</strong>hing<br />
- Increased rate <strong>of</strong> waste paper utilization<br />
- Removal <strong>of</strong> silica before evaporation process (for<br />
rice straw)<br />
- Efficient air pollution control equipment<br />
- Advance wastewater treatment<br />
Long Term Measures<br />
- Prohibiting new small scale mill development<br />
wherever possible<br />
- Process monitoring and control by expert system<br />
***<br />
***<br />
***<br />
***<br />
***<br />
***<br />
****<br />
***<br />
***<br />
***<br />
****<br />
****<br />
****<br />
****<br />
****<br />
***<br />
***<br />
***<br />
***<br />
***<br />
****<br />
***<br />
***<br />
***<br />
****<br />
****<br />
***<br />
****<br />
****<br />
***<br />
***<br />
***<br />
***<br />
***<br />
****<br />
***<br />
*****<br />
**** **** **** ****<br />
#<br />
For e<strong>ac</strong>h pollution abatement measure, <strong>th</strong>e relative scope <strong>of</strong> application is shown by number <strong>of</strong><br />
asterisks as in Table 5.5.<br />
****<br />
****<br />
****<br />
***<br />
***<br />
****<br />
****<br />
***<br />
****<br />
***<br />
***<br />
***<br />
***<br />
***<br />
****<br />
***<br />
****<br />
****<br />
***<br />
****<br />
****<br />
****<br />
***
Cross Country Comparison <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry49<br />
5.7 Conclusion<br />
The energy saving potential in <strong>th</strong>e pulp and paper industry for <strong>th</strong>e European Community as a whole<br />
was estimated as 20-30% <strong>of</strong> <strong>th</strong>e current energy consumed. Therefore, <strong>th</strong>e potential <strong>of</strong> energy saving<br />
in <strong>th</strong>e developing countries where outdated technologies dominate, could be substantially higher.<br />
Since <strong>th</strong>e industry generates waste materials which can be used as fuel, self-power generation in<br />
cogeneration mode could be one <strong>of</strong> <strong>th</strong>e most promising measures to improve <strong>th</strong>e overall energy<br />
efficiency <strong>of</strong> <strong>th</strong>e industry. Major energy savings could also <strong>ac</strong>crue from <strong>th</strong>e application <strong>of</strong> <strong>th</strong>ermal<br />
upgrading systems.<br />
The pulp and paper industry is a favorable candidate for excess power generation and supply to <strong>th</strong>e<br />
grid. Therefore, encouragement from <strong>th</strong>e governmental institutions by means <strong>of</strong> regulations and<br />
incentives would not only improve <strong>th</strong>e energy efficiency <strong>of</strong> <strong>th</strong>e industry but also be economically<br />
beneficial to <strong>th</strong>e country. To <strong>ac</strong>hieve better energy efficiency in <strong>th</strong>e pulp and paper industry, <strong>th</strong>e type<br />
<strong>of</strong> useful support <strong>th</strong>e government institutions can extend are setting target for dissemination <strong>of</strong> e<strong>ac</strong>h<br />
promising energy efficient technology, spreading knowledge about new technologies, organizing<br />
energy conferences and workshops, and encouraging research and development <strong>ac</strong>tivities.<br />
Energy efficient and environmentally sound pulping processes have been mainly developed for<br />
wood pulp which currently <strong>ac</strong>counts for 90% <strong>of</strong> <strong>th</strong>e world’s pulp. Therefore, for countries like<br />
China and India where non-wood pulps dominate, it is necessary to carry out research work on<br />
energy efficient and environmentally sound pulping for non-wood materials. For countries where<br />
limited or no energy conservation measures have been undertaken, installation <strong>of</strong> measuring<br />
equipment in <strong>th</strong>e processes and data <strong>ac</strong>quisition could help to plan and take <strong>ac</strong>tions in improving<br />
energy efficiency and reducing pollution from <strong>th</strong>e industry.<br />
As <strong>th</strong>is industry is an important water polluter, serious consideration should be given to recycle and<br />
reuse <strong>th</strong>e water wi<strong>th</strong>in <strong>th</strong>e plant as much as possible. Due to <strong>th</strong>e chemical content <strong>of</strong> pulp washing<br />
water, it is toxic for aquatic lives; <strong>th</strong>erefore improved chemical recovery me<strong>th</strong>ods should be<br />
pr<strong>ac</strong>ticed to recover as much chemicals as possible, which does not only reduce <strong>th</strong>e pollution load<br />
but also <strong>th</strong>e amount <strong>of</strong> chemical required for <strong>th</strong>e process. Burning fuels for power generation and in<br />
<strong>th</strong>e boilers is a source <strong>of</strong> air pollution. Any measure taken for energy efficiency improvement<br />
ultimately leads to reduction in air pollution loads.
50 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
6. PROFILE OF THE PULP AND PAPER INDUSTRY IN SELECTED ASIAN<br />
COUNTRIES<br />
This section evaluates <strong>th</strong>e current status and technological trajectory <strong>of</strong> <strong>th</strong>e pulp and paper industry<br />
in four <strong>Asian</strong> countries, namely China, India, <strong>th</strong>e Philippines and Sri Lanka.<br />
6.1 COUNTRY REPORT: CHINA<br />
6.1.1 Introduction<br />
The pulp and paper industry is one <strong>of</strong> <strong>th</strong>e most energy-intensive and polluting industries in China.<br />
In 1993, it <strong>ac</strong>counted for 9.8% <strong>of</strong> <strong>th</strong>e total industrial waste water discharge and 38.2% <strong>of</strong> <strong>th</strong>e total<br />
BOD discharge from <strong>th</strong>e industrial sector. Serious environmental pollution becomes increasingly<br />
un<strong>ac</strong>ceptable as it harms <strong>th</strong>e heal<strong>th</strong> <strong>of</strong> local residents and destroys <strong>th</strong>e local ecology. The Chinese<br />
government has been trying to tighten environmental regulations in order to reduce <strong>th</strong>e pollution<br />
level from paper mills. Implementation <strong>of</strong> <strong>th</strong>ese regulations, however, has encountered numerous<br />
difficulties due to <strong>th</strong>e complexities <strong>of</strong> <strong>th</strong>e industry.<br />
Low energy efficiency and high environmental pollution from <strong>th</strong>e pulp and paper industry are not<br />
only caused by <strong>th</strong>e b<strong>ac</strong>kwardness <strong>of</strong> technological f<strong>ac</strong>ilities, <strong>th</strong>ey are also consequences <strong>of</strong> <strong>th</strong>e<br />
industry’s organization in terms <strong>of</strong> plant distribution and ownership. Problems in <strong>th</strong>e industry<br />
should <strong>th</strong>erefore by analyzed in a systematic manner to take into consideration various inter<strong>ac</strong>tive<br />
f<strong>ac</strong>tors <strong>th</strong>at determine energy efficiency and environmental pollution.<br />
The objective <strong>of</strong> <strong>th</strong>is section is to find out <strong>th</strong>e determining f<strong>ac</strong>tors and major causes <strong>of</strong><br />
environmental pollution in <strong>th</strong>e pulp and paper industry. In what follows, an analysis <strong>of</strong> <strong>th</strong>e<br />
evolution <strong>of</strong> energy efficiency and environmental pollution in relation to its technological evolution<br />
is presented. Firstly, <strong>th</strong>e technological trajectory <strong>of</strong> <strong>th</strong>e pulp and paper industry is laid out, and<br />
secondly, an analysis <strong>of</strong> <strong>th</strong>e evolution <strong>of</strong> energy efficiency and assessment <strong>of</strong> <strong>th</strong>e environmental<br />
externalities is done. Then <strong>th</strong>e potential for energy efficiency improvement and pollution<br />
abatement <strong>th</strong>rough technological changes is analyzed. Finally, <strong>th</strong>e status <strong>of</strong> <strong>th</strong>e application <strong>of</strong> new<br />
technologies is presented and some recommendations for fur<strong>th</strong>er studies are proposed.<br />
6.1.1.1 Evolution <strong>of</strong> China’s pulp and paper industry<br />
It is well known <strong>th</strong>at <strong>th</strong>e ancient paper making technology was one <strong>of</strong> <strong>th</strong>e four famous ancient<br />
inventions <strong>of</strong> China. It is also <strong>ac</strong>knowledged <strong>th</strong>at China's ancient paper making technology had<br />
played a great role in <strong>th</strong>e global paper making industry, and in <strong>th</strong>e progress and dissemination <strong>of</strong><br />
human science and culture <strong>ac</strong>ross countries in <strong>th</strong>e history <strong>of</strong> human development.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 51<br />
The sole process used in <strong>th</strong>e pulp and paper mills in China, however, was <strong>th</strong>e simple manual<br />
operation me<strong>th</strong>od. Not until 1884, when Shanghai Huazhang Paper Mill was put into operation in<br />
East China, was <strong>th</strong>e m<strong>ac</strong>hine-made paper production technology introduced. The technology was<br />
invented in Europe in <strong>th</strong>e year 1799. The country’s pulp and paper industry developed slowly due<br />
to various internal as well as external reasons. By 1949, <strong>th</strong>e national m<strong>ac</strong>hine-made paper and<br />
paperboard production was only 108 <strong>th</strong>ousand tons compared to <strong>th</strong>e manual production <strong>of</strong> 120<br />
<strong>th</strong>ousand tons.<br />
Generally, <strong>th</strong>e features <strong>of</strong> Old China's paper making industry can be summarized as follows:<br />
- From <strong>th</strong>e point <strong>of</strong> view <strong>of</strong> paper making, manually operated paper production<br />
<strong>ac</strong>counted for two <strong>th</strong>irds, while m<strong>ac</strong>hine-made paper production <strong>ac</strong>counted for only<br />
one-<strong>th</strong>ird <strong>of</strong> <strong>th</strong>e total paper output.<br />
- From <strong>th</strong>e point <strong>of</strong> view <strong>of</strong> paper consumption, domestic mechanical paper production<br />
met just less <strong>th</strong>an one <strong>th</strong>ird <strong>of</strong> <strong>th</strong>e national demand. The rest was met by imports.<br />
- As for <strong>th</strong>e local distribution <strong>of</strong> <strong>th</strong>e industry <strong>ac</strong>ross China, mechanized paper making<br />
plants were found mainly in a few coastal provinces, while manually operated paper<br />
making mills were located mainly in several sou<strong>th</strong>ern provinces abundant in bamboo<br />
resources.<br />
- As far as mechanical paper making technology is concerned, most key m<strong>ac</strong>hine<br />
components needed for <strong>th</strong>e industry were imported from abroad because <strong>of</strong> <strong>th</strong>e severe<br />
l<strong>ac</strong>k <strong>of</strong> industrial infrastructure.<br />
6.1.1.2 Major <strong>ac</strong>hievements in China’s pulp and paper industry<br />
Since P.R. China was founded in 1949, a drastic change has occurred in its booming pulp and<br />
paper industry. By <strong>th</strong>e year 1992, China's pulp production, paper & paperboard production and<br />
national paper & paperboard consumption ranked <strong>th</strong>ird in <strong>th</strong>e world, after USA and Japan.<br />
China's current pulp and paper industry has developed since 1952, when its total mechanical paper<br />
& paperboard output was only 372,000 tons, to 17.25 million tons by <strong>th</strong>e year 1992 wi<strong>th</strong> a<br />
consistent annual grow<strong>th</strong> rate <strong>of</strong> 10%. Particularly during <strong>th</strong>e last decade, <strong>th</strong>e average grow<strong>th</strong> <strong>of</strong><br />
paper & paperboard production re<strong>ac</strong>hed 14%, a high value in <strong>th</strong>e history <strong>of</strong> world paper industry.<br />
Its gross output in 1993 re<strong>ac</strong>hed 61.12 billion Yuan, or 1.54% <strong>of</strong> <strong>th</strong>e total industry gross output<br />
value. Its net output <strong>of</strong> 15.1 billion Yuan <strong>ac</strong>counted for 1.18% <strong>of</strong> <strong>th</strong>e national industry value.<br />
Table 6.1.1 shows <strong>th</strong>e contribution <strong>of</strong> China's pulp, paper & paperboard production to <strong>th</strong>e world<br />
total. Table 6.1.2 gives <strong>th</strong>e situation <strong>of</strong> paper production and consumption in <strong>th</strong>e world and in <strong>th</strong>e<br />
country as well.
52 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Table 6.1.1 Status <strong>of</strong> China's mechanical pulp, paper & paperboard productions<br />
Year 1985 1986 1987 1988 1989 1990<br />
Share <strong>of</strong> pulp production in <strong>th</strong>e<br />
world output, %<br />
4.5 4.5 4.8 5.2 5.68 5.91<br />
Ranked position worldwide 7 7 7 7 6 5<br />
Share <strong>of</strong> <strong>th</strong>e world paper &<br />
paperboard production, %<br />
4.7 4.9 5.3 5.6 5.70 5.75<br />
Ranked position worldwide<br />
Sources: [1,2,3,10]<br />
6 5 4 4 4 4<br />
Table 6.1.2 Global paper industry production and consumption in 1990<br />
Item Number <strong>of</strong><br />
F<strong>ac</strong>tories<br />
Production<br />
cap<strong>ac</strong>ity<br />
(10 3 ton)<br />
Per capita<br />
consumption<br />
(kg)<br />
Superficial<br />
consumption<br />
(10 3 ton)<br />
Production<br />
(10 3 ton)<br />
(1) (2) (1) (2) (1) (2) (1) (2)<br />
China 250* 176* 15500 11000 12.6 14429 9838 13719 9500<br />
World 4372 1352 266253 183503 44.8 237107 160577 238781 160649<br />
China’s share in 5.7 13 5.8 6.0 ~6.09 5.98 ~ 5.70 ~ 5.91<br />
<strong>th</strong>e world (%)<br />
Notes: (1) Paper & paperboard; (2) Pulp<br />
6.13 5.75<br />
* The f<strong>ac</strong>tories counted here refer only to <strong>th</strong>ose wi<strong>th</strong> a cap<strong>ac</strong>ity <strong>of</strong> more <strong>th</strong>an 30,000<br />
ton/year.<br />
Source: [10]<br />
Figures 6.1.1 and 6.1.2 show China's pulp, paper & paperboard production.<br />
Though a considerable <strong>ac</strong>hievement has been made in China's Pulp & Paper Industry since 1949,<br />
<strong>th</strong>ere still exists a strong impetus to boost China's pulp & paper industry to meet its immense<br />
market demand for paper consumption by more <strong>th</strong>an 1.2 billion people. It can be seen from Table<br />
6.1.2 <strong>th</strong>at <strong>th</strong>e 1990 average paper & paperboard consumption per capita in China was still only a<br />
quarter <strong>of</strong> world average level. China's paper & paperboard consumption <strong>ac</strong>counted only for 6%<br />
<strong>of</strong> <strong>th</strong>e world’s total volume, while its population <strong>ac</strong>counted for some 20% <strong>of</strong> <strong>th</strong>e global<br />
population. In 1992, net imports <strong>of</strong> paper & paperboard re<strong>ac</strong>hed 2.34 million tons, and imported<br />
commercial pulp also re<strong>ac</strong>hed 600,000 ton to fill <strong>th</strong>e gap between domestic production and<br />
demand. Self-sufficiency rate for paper demand has decreased recently in line wi<strong>th</strong> China's<br />
escalating economic development. It is predicted by o<strong>th</strong>er relevant research <strong>th</strong>at China’s economy<br />
will maintain current aggressive grow<strong>th</strong> trend in a foreseeable period. By <strong>th</strong>e turn <strong>of</strong> <strong>th</strong>e century,<br />
its grow<strong>th</strong> rate will be maintained at 7-9%. According to a synchronous grow<strong>th</strong> principle <strong>of</strong> paper<br />
& paperboard consumption wi<strong>th</strong> GDP, <strong>th</strong>e grow<strong>th</strong> rate <strong>of</strong> domestic paper demand will also be<br />
maintained at 7-9%. This means <strong>th</strong>at <strong>th</strong>e market demand for paper in 2000 will re<strong>ac</strong>h 331 million<br />
tons.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 53<br />
Production 10,000 tonne<br />
Production 10,000 tonne<br />
1800<br />
1600<br />
1400<br />
1200<br />
1000<br />
800<br />
600<br />
400<br />
200<br />
total<br />
manual<br />
mechanical<br />
0<br />
1940 1950 1960 1970 1980 1990 2000<br />
Figure 6.1.1 Production <strong>of</strong> paper & paperboard in China since 1949<br />
1000<br />
900<br />
800<br />
700<br />
600<br />
500<br />
400<br />
300<br />
200<br />
100<br />
0<br />
1945 1950 1955 1960 1965 1970 1975 1980 1985 1990<br />
Figure 6.1.2 M<strong>ac</strong>hine-made pulp production in China since 1949
54 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Though paper & paperboard consumption <strong>of</strong> China was at number 3 in <strong>th</strong>e world in 1992, its<br />
average consumption per capita was only 16.7 kg per person, or less <strong>th</strong>an one half <strong>of</strong> <strong>th</strong>e world<br />
average value <strong>of</strong> 45.3 kg per person. If <strong>th</strong>is indicator for China is to re<strong>ac</strong>h one half <strong>of</strong> <strong>th</strong>e world<br />
average level by 2000, a production increment <strong>of</strong> more <strong>th</strong>an 10 million tons from 1992's 17.25<br />
million tons will <strong>th</strong>en be required.<br />
Considering <strong>th</strong>erefore <strong>th</strong>e impossibility <strong>of</strong> too much dependence on imports to meet <strong>th</strong>e domestic<br />
paper market demand, China’s pulp and paper industry in <strong>th</strong>e foreseeable future calls for a fast and<br />
sustainable development.<br />
6.1.2 Technological trajectory <strong>of</strong> China’s paper industry<br />
6.1.2.1 Pulp and paper production and development<br />
In 1949, m<strong>ac</strong>hine-made paper output <strong>ac</strong>counted only for 47% <strong>of</strong> total volume. By 1985, <strong>th</strong>e share<br />
<strong>of</strong> mechanical paper to <strong>th</strong>e total output rose to 97.9%. Manually operated paper production (less<br />
<strong>th</strong>an 366,000 tons, <strong>th</strong>e peak volume in 1932) is reserved for some special kinds <strong>of</strong> traditional<br />
papers such as <strong>th</strong>e most famous Xuanzi. Figure 6.1.3 illustrates <strong>th</strong>e evolution <strong>of</strong> China's mechanical<br />
paper making capability.<br />
Production Cap<strong>ac</strong>ity million ton<br />
20<br />
18<br />
16<br />
14<br />
12<br />
10<br />
8<br />
6<br />
4<br />
2<br />
0<br />
1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995<br />
Figure 6.1.3 Production cap<strong>ac</strong>ities <strong>of</strong> China's paper & paperboard
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 55<br />
Before 1949, <strong>th</strong>e types <strong>of</strong> mechanical papers were only several dozens, wi<strong>th</strong> some common kinds<br />
for printing, writing, p<strong>ac</strong>kaging, etc. The key reason for <strong>th</strong>is was <strong>th</strong>e severe l<strong>ac</strong>k <strong>of</strong> mechanical<br />
manuf<strong>ac</strong>turing capability. Along wi<strong>th</strong> <strong>th</strong>e rapid grow<strong>th</strong> <strong>of</strong> mechanical pulp and paper production<br />
cap<strong>ac</strong>ity, <strong>th</strong>e number <strong>of</strong> types <strong>of</strong> various paper & paperboard has also increased to a great extent.<br />
Wi<strong>th</strong>in <strong>th</strong>e first five-year planning period, for instance, newly-added types <strong>of</strong> paper re<strong>ac</strong>hed 79,<br />
including paper s<strong>ac</strong>k, condenser paper, blue print base paper, pictorial paper, fax paper, etc. By <strong>th</strong>e<br />
end <strong>of</strong> 1985, <strong>th</strong>e total number <strong>of</strong> paper & paperboard products in China increased to more <strong>th</strong>an<br />
five hundred, a number which could meet all sectoral basic demands. The types <strong>of</strong> pulp also<br />
increased simultaneously wi<strong>th</strong> <strong>th</strong>e increased demand for diverse kinds <strong>of</strong> paper products during <strong>th</strong>e<br />
same period. The share <strong>of</strong> various paper & paperboard products in China in 1992 is shown in<br />
Table 6.1.3.<br />
Table 6.1.3 Composition <strong>of</strong> types <strong>of</strong> paper and paperboard in China in 1992<br />
Type Press &<br />
printing<br />
Writing<br />
paper<br />
P<strong>ac</strong>kin<br />
g paper<br />
Industrial<br />
paper<br />
Paperboard Living<br />
&<br />
o<strong>th</strong>er<br />
Share(%) 25 10.6 11 3.0 42 8.4<br />
The quality <strong>of</strong> <strong>th</strong>e different paper & paperboard products has also been improving gradually. By<br />
1985, six products were honored as <strong>th</strong>e State Golden Quality Products, 46 products as State Silver<br />
Quality Products and o<strong>th</strong>er 176 products as Light Industry Excellent Quality Products. For<br />
example, a paper for computer use made by <strong>th</strong>e Shandong Paper Mill General, is regarded to be <strong>of</strong><br />
good quality from all major technical performance indicators, and is reckoned to catch up wi<strong>th</strong><br />
and/or exceed international levels <strong>of</strong> paper <strong>of</strong> <strong>th</strong>e same kind. Ano<strong>th</strong>er example is <strong>th</strong>e Chinesemade<br />
toilet papers which held a 90% share <strong>of</strong> <strong>th</strong>e market in <strong>th</strong>e Hong Kong area in 1986.<br />
The much increased number <strong>of</strong> product types as well as <strong>th</strong>e much improved quality <strong>of</strong> paper<br />
product embody <strong>th</strong>e rise <strong>of</strong> <strong>th</strong>e technical level in <strong>th</strong>e Chinese paper industry.<br />
6.1.2.2 Development <strong>of</strong> pulp & paper enterprises<br />
In <strong>th</strong>e context <strong>of</strong> China, pulp and paper mills can be classified into <strong>th</strong>ree categories in terms <strong>of</strong><br />
<strong>th</strong>eir cap<strong>ac</strong>ity <strong>of</strong> production: large mills wi<strong>th</strong> a cap<strong>ac</strong>ity <strong>of</strong> more <strong>th</strong>an 30,000 tons/year; medium<br />
size mills wi<strong>th</strong> a cap<strong>ac</strong>ity <strong>of</strong> 10,000 to 30,000 tons/year; and small mills wi<strong>th</strong> a cap<strong>ac</strong>ity <strong>of</strong> less <strong>th</strong>en<br />
10,000 tons/year.<br />
In 1949, <strong>th</strong>ere were only little more <strong>th</strong>an 100 mills <strong>ac</strong>ross <strong>th</strong>e country. By <strong>th</strong>e end <strong>of</strong> 1992,<br />
however, <strong>th</strong>e number <strong>of</strong> paper mills increased to more <strong>th</strong>an 9,000 [13]. From Chinese statistics<br />
[11], <strong>th</strong>e number <strong>of</strong> total enterprises was 11,940. The production <strong>of</strong> <strong>th</strong>e biggest scale paper mill<br />
increased from 30,000 to more <strong>th</strong>an 150,000 tons/year. Among <strong>th</strong>em, 1665 paper mills belonged<br />
to <strong>th</strong>e China Light Industry Commission (CLIC, i.e., <strong>th</strong>e former Light Industry Ministry <strong>of</strong> China)
56 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
wi<strong>th</strong> an average enterprise scale <strong>of</strong> around 4700 tons/year. The o<strong>th</strong>er mills belonged to <strong>th</strong>e<br />
agriculture, forest or rural township systems wi<strong>th</strong> an average enterprise scale <strong>of</strong> only 1842<br />
tons/year. Thus, <strong>th</strong>e national average paper mill cap<strong>ac</strong>ity was only about 2500 tons/year. In<br />
comparison, <strong>th</strong>e average pulp mill cap<strong>ac</strong>ity in some industrialized countries is 170,000 tons/year,<br />
wi<strong>th</strong> <strong>th</strong>e average output being 61 <strong>th</strong>ousand tons per unit paper and paperboard mill. The large<br />
number <strong>of</strong> dispersed paper making enterprises wi<strong>th</strong> smaller cap<strong>ac</strong>ities is considered to be <strong>th</strong>e main<br />
reason for bad scale-benefit, low management level, lagging behind technical level as well as severe<br />
environmental pollution.<br />
In most cases, China’s paper enterprises are integrated pulp and paper mills, while <strong>th</strong>ose which<br />
solely produce commercial pulp number a few. Only a minority <strong>of</strong> paper mills located in urban<br />
areas use commercial pulp or waste paper for production.<br />
88%<br />
large scale medium scale<br />
small scale<br />
2%<br />
10%<br />
57%<br />
28%<br />
large scale medium scale small scale<br />
Figure 6.1.4 Composition <strong>of</strong> paper mills and <strong>th</strong>eir contribution to <strong>th</strong>e total production<br />
Not all paper enterprises belong to <strong>th</strong>e China Light Industry Commission (CLIC) or <strong>th</strong>e<br />
pr<strong>of</strong>essional management ministry for light industrial products such as paper, sugar, glass, wine,<br />
etc. The agricultural sector (including rural township and reclamation systems), forest sector and<br />
military systems have <strong>th</strong>eir own paper mills. In township paper mills, <strong>th</strong>e dominant process is<br />
ei<strong>th</strong>er <strong>th</strong>e lime-based yellow strawboard production or p<strong>ac</strong>kaging-paper production by recovery <strong>of</strong><br />
waste paper. Most mills belonging to <strong>th</strong>e forest system mainly use timber materials to produce<br />
unble<strong>ac</strong>hed pulp and/or paperboard. Those belonging to <strong>th</strong>e agricultural reclamation and military<br />
systems are usually straw-based integrated mills. This complex mix creates a barrier for <strong>th</strong>e<br />
pr<strong>of</strong>essional management <strong>of</strong> <strong>th</strong>e pulp and paper industry.<br />
15%
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 57<br />
6.1.2.3 Technological progress in China’s pulp and paper industry<br />
a. Technological events<br />
In <strong>th</strong>e course <strong>of</strong> <strong>th</strong>e paper industry’s technological development, two aspects were equally focused<br />
and combined. One, it deeply depended on domestic R&D capability and diffusion <strong>of</strong> domestic<br />
advanced experiences and technologies. Second, much efforts were pl<strong>ac</strong>ed on introducing foreign<br />
advanced technologies and equipment as well as learning and digesting internationally advanced<br />
expertise. Some important milestones in <strong>th</strong>e progress <strong>of</strong> <strong>th</strong>e paper making technology in China can<br />
be briefly depicted as follows:<br />
- During <strong>th</strong>e 1950s, a series <strong>of</strong> Fourdrinier paper m<strong>ac</strong>hines and auxiliary f<strong>ac</strong>ilities, e<strong>ac</strong>h<br />
wi<strong>th</strong> a cap<strong>ac</strong>ity <strong>of</strong> 50 tons/day, were designed and manuf<strong>ac</strong>tured by domestic R&D<br />
experts for some key expansion projects.<br />
- In 1957, <strong>th</strong>e first ejection furn<strong>ac</strong>e made in China for alkali recovery was installed in<br />
Jiamusi Paper Mill.<br />
- In <strong>th</strong>e meantime, some large cap<strong>ac</strong>ity paper making m<strong>ac</strong>hines <strong>of</strong> 100, 150, or 200<br />
tons/day cap<strong>ac</strong>ity were imported. Log-milling m<strong>ac</strong>hines <strong>of</strong> international standards were<br />
also imported.<br />
- Around 1970, some key imported foreign equipment included continuous digester <strong>of</strong><br />
straw pulp, pressurized pulp ble<strong>ac</strong>hing m<strong>ac</strong>hines, ejection furn<strong>ac</strong>es for alkali recovery,<br />
150 tons/day heat wood-chip milling m<strong>ac</strong>hines, etc.<br />
- Some domestically developed technologies, such as on-line moisture control system,<br />
paper fold-pressing technology & mill pulp making were popularized in national paper<br />
mills.<br />
- Alkali recovery capability from pulp making bl<strong>ac</strong>k liquor increased from a trifle in 1957<br />
to 362,200 ton/year in 1988 or 36.66% <strong>of</strong> <strong>th</strong>e total alkali consumption for <strong>th</strong>e year. In<br />
Qingzhou Paper Mill, Nanping Paper Mill and Jiamusi Paper Mill, production-needed<br />
alkali can approximately be provided by <strong>th</strong>eir alkali recovery systems. Electrostatic<br />
precipitators were also disseminated to large and medium size paper mills, which proved<br />
beneficial bo<strong>th</strong> for alkali recovery and for dust prevention. Figure 6.1.5 illustrates <strong>th</strong>e<br />
grow<strong>th</strong> curve <strong>of</strong> alkali recovery from 1979.<br />
- The capability <strong>of</strong> integrated exploitation <strong>of</strong> sulfite pulp wastewater for production <strong>of</strong><br />
some by-products was also boosted
58 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
- Since 1968, <strong>th</strong>e new process <strong>of</strong> utilizing ammonium bisulfite straw pulp has been<br />
popularized in many small paper mills in Shandong, Sichuan and o<strong>th</strong>er provinces. Using<br />
<strong>th</strong>is process, wastewater can be directly used for farm irrigation.<br />
- Since 1978, new systems for loop or cycle utilization <strong>of</strong> clean water in paper mills were<br />
created, e.g. tilt-plate precipitating me<strong>th</strong>od in Tianjing Paper Mill, tilt-tube precipitating<br />
me<strong>th</strong>od in Shanghai Vanguard Paper Mill, and air buoyancy me<strong>th</strong>od in Suzhou Huashen<br />
Paper Mill.<br />
1000 ton<br />
400<br />
350<br />
300<br />
250<br />
200<br />
150<br />
100<br />
50<br />
Cap<strong>ac</strong>ity<br />
Production<br />
0<br />
1979 1980 1982 1984 1986 1988<br />
Year<br />
Figure 6.1.5 Grow<strong>th</strong> curves <strong>of</strong> alkali recovery from 1979 to 1988<br />
b. Technological advances wi<strong>th</strong> imported foreign technologies, f<strong>ac</strong>ilities and equipment<br />
Since <strong>th</strong>e early 1980s, <strong>th</strong>e scale <strong>of</strong> technology import has been increasing step by step so as to<br />
narrow <strong>th</strong>e technical gap between <strong>th</strong>e paper industry <strong>of</strong> China and <strong>th</strong>e developed countries. From<br />
1980 to 1988, about US$ 300 million had been spent to update <strong>th</strong>e pulp and papermaking<br />
technologies and equipment in <strong>th</strong>e country. It is also estimated <strong>th</strong>at more <strong>th</strong>an US$ 1 billion had<br />
been spent for importing technologies and equipment from 1989 to 1995. The technology<br />
processes adopted toge<strong>th</strong>er wi<strong>th</strong> <strong>th</strong>e import <strong>of</strong> equipment are listed below:<br />
- Technological transformation, upgrading and/or overhauling in some state-owned key<br />
enterprises: 150 t/d paper m<strong>ac</strong>hine transformation at <strong>th</strong>e Qinzhou Paper Mill, combined<br />
wi<strong>th</strong> <strong>th</strong>e installation <strong>of</strong> advanced equipment from Beloit Corp. (<strong>th</strong>e project proved to be<br />
very successful and brought about 50% increment in production cap<strong>ac</strong>ity, better quality<br />
<strong>of</strong> paper s<strong>ac</strong>k product and new type <strong>of</strong> elastic paper s<strong>ac</strong>k); 200 t/d paper m<strong>ac</strong>hine<br />
transformation at <strong>th</strong>e Jiamusi Paper Mill; 100 t/d paper m<strong>ac</strong>hine transformations at <strong>th</strong>e
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 59<br />
Yueyang and Liujiang Paper Mills; and Nanpin No. 1 paper m<strong>ac</strong>hine transformations<br />
which was a typical case <strong>of</strong> optimum adoption <strong>of</strong> imported equipment to match wi<strong>th</strong> <strong>th</strong>e<br />
local situation.<br />
- Installation <strong>of</strong> new and advanced technology and equipment, including exhausted heat<br />
recovery equipment from Sweden for a 150 t/d TMP production line at Jilin Pulp &<br />
Paper Mill, enabling it to produce CTMP and make newsprint paper; 60 t/d<br />
sulf<strong>of</strong>ication CMP line imported from Finland at <strong>th</strong>e Shiyan Pulp and Paper Mill;<br />
horizontal continuous digesters <strong>of</strong> Sunds Defibration Corp. <strong>of</strong> Sweden installed at<br />
Jiaozuo, Dezhou, Fuzhou and Jihe, etc.; <strong>th</strong>e first set <strong>of</strong> Swedish Kamyr’s Vertical<br />
Continuous Digester installed at Yibin Paper Mill; plank-style membrane vaporizer and<br />
concentrator from Finland Ahlstrom Corp. installed at <strong>th</strong>e Jiamusi and Liujiang paper<br />
mills; white silt kiln imported from <strong>th</strong>e same corporation for Jilin Paper Mill; horizontal<br />
belt-style v<strong>ac</strong>uum washer for spent sulfite liquor (so-called red liquor) from English<br />
Bl<strong>ac</strong>k Clawson Corp. installed at Kaisan Pulp Mill and Guangzhou Paper Mill; de-inking<br />
equipment <strong>of</strong> <strong>th</strong>e same corporation at Beijing’s No. 1 Paper Mill; nearly 50 sets <strong>of</strong><br />
constant moisture-control systems for paper making from Measurex Corp. and Accupay<br />
Corp. <strong>of</strong> USA and Lippka Corp. <strong>of</strong> Germany, etc., which can stabilize paper moisture<br />
and paper mass; coated paper m<strong>ac</strong>hine and coating material process line imported from<br />
France and Germany at Shanghai Jiangnan Pulp & Paper Mill. Besides <strong>th</strong>e abovementioned<br />
state-<strong>of</strong>-art technological equipment from <strong>th</strong>e industrialized countries, a<br />
number <strong>of</strong> second-hand paper m<strong>ac</strong>hines and paperboard m<strong>ac</strong>hines were also purchased<br />
at costs <strong>of</strong> about one fif<strong>th</strong> to one ten<strong>th</strong> <strong>th</strong>at <strong>of</strong> <strong>th</strong>e brand-new ones.<br />
c. Recent developments in <strong>th</strong>e domestic production process and equipment<br />
Some dominant home-developed technological advances since 1990 include:<br />
- Large-size alkali recovery furn<strong>ac</strong>es wi<strong>th</strong> cap<strong>ac</strong>ities <strong>of</strong> 200 and 300 t/d have been built at<br />
Jiamusi and Jilin paper mills, respectively. Fur<strong>th</strong>ermore, a set <strong>of</strong> alkali recovery furn<strong>ac</strong>e<br />
wi<strong>th</strong> <strong>th</strong>e biggest pulp-dealing cap<strong>ac</strong>ity <strong>of</strong> 1000 t/d was exported to Indonesia.<br />
- Small-size whole system equipment <strong>of</strong> 30 t/d CTMP cap<strong>ac</strong>ity has been successfully<br />
manuf<strong>ac</strong>tured in Shanghai and put into operation in Fujian Province.<br />
- Several sets <strong>of</strong> locally made horizontal-tube continuous digester <strong>of</strong> 50 t/d straw pulp<br />
making cap<strong>ac</strong>ity have been made and put into operation in China, after importing and<br />
adapting relative technologies from Swedish Sunds Corp.<br />
- New jam-pro<strong>of</strong> energy-saving pump for pulp transport was designed successfully wi<strong>th</strong> an<br />
energy conservation benefit <strong>of</strong> 20% compared to conventional pumps. These pumps
60 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
were installed at a dozen paper mills, proving additional comp<strong>ac</strong>t, low-noise and little<br />
oscillation features.<br />
- Locally made new v<strong>ac</strong>uum pulp washers wi<strong>th</strong> 35 m 2 area were used at some newly built<br />
paper projects.<br />
- As an advancement in <strong>th</strong>e bl<strong>ac</strong>k liquor vaporization system, a whole set <strong>of</strong> plate-style<br />
membrane vaporizer systems (wi<strong>th</strong> 50% higher efficiency <strong>th</strong>an <strong>th</strong>e old ones and bigger<br />
load) have been commissioned at <strong>th</strong>e Qinzhou Pulp & Paper Mill.<br />
- Small-size domestic-made waste paper disposing and de-inking systems have been put<br />
into operation at Xingshi Paper Mill.<br />
- High intensity press and polyester dry net for repl<strong>ac</strong>ement <strong>of</strong> conventional dry canvas in<br />
<strong>th</strong>e process <strong>of</strong> papermaking.<br />
- Heat pump systems for <strong>th</strong>e paper m<strong>ac</strong>hine’s dryer section were used at Minfen Pulp &<br />
Paper Group, Tianjing Paper Mill and Qiqihar Pulp & Paper Mill. Their operations<br />
showed <strong>th</strong>at specific steam consumptions per ton <strong>of</strong> paper were reduced by 29.4%,<br />
28.3% and 36.6%, respectively. The heat pump-based technology can substitute<br />
conventional two- or <strong>th</strong>ree-stage cascade system, making full use <strong>of</strong> steam <strong>th</strong>ermal<br />
energy and available energy to remove condensate smoo<strong>th</strong>ly.<br />
During <strong>th</strong>e last four decades, China’s researchers in <strong>th</strong>e paper field have made many more<br />
<strong>ac</strong>hievements, including <strong>th</strong>e development <strong>of</strong> new types <strong>of</strong> raw materials for pulp making,<br />
development <strong>of</strong> new types <strong>of</strong> paper & paperboard, retr<strong>of</strong>itting or improvement <strong>of</strong> pulping<br />
processes, R&D for some key equipment, integrated utilization <strong>of</strong> digested wastewater,<br />
development and utilization <strong>of</strong> emulsion materials, filling materials and o<strong>th</strong>er chemical agents in<br />
<strong>th</strong>e paper producing processes, as well as some basic <strong>ac</strong>ademic researches in universities and<br />
research institutes. As for wastewater pollution abatement, eight key <strong>ac</strong>hievements have also been<br />
made concerning chemical agents recovery, sulfite pulping wastewater integrated exploitation, biochemical<br />
treatment <strong>of</strong> pulping wastewater, etc.<br />
6.1.2.4 Two prominent technological char<strong>ac</strong>teristics<br />
In <strong>th</strong>e mixes <strong>of</strong> pulp production, <strong>th</strong>ere exists an eminent char<strong>ac</strong>teristic for China's paper industry,<br />
i.e., straw-material-made pulp holds a dominant share in <strong>th</strong>e mix (grass-straw pulp 63%), while<br />
wood pulp <strong>ac</strong>counted for as low as 26% in <strong>th</strong>e mix. It is well known <strong>th</strong>at using wood as a pulping<br />
raw material is better <strong>th</strong>an using straw from <strong>th</strong>e point <strong>of</strong> view <strong>of</strong> pulp production efficiency,<br />
environmental protection, or from wood material's economical utilization. At present, wood<br />
material <strong>ac</strong>counts for more <strong>th</strong>an 90% <strong>of</strong> <strong>th</strong>e global pulp production.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 61<br />
Ano<strong>th</strong>er problem existing in China’s paper industry is <strong>th</strong>e very low level <strong>of</strong> waste paper recycling.<br />
In 1988, waste-paper pulp (including imported waste paper) <strong>ac</strong>counted for 22.5% only, while <strong>th</strong>e<br />
same indicators for Japan and European Union were 50% and 48%, respectively. A higher<br />
percentage <strong>of</strong> waste paper pulp in <strong>th</strong>e total pulp production is beneficial for resource conservation,<br />
energy savings and environmental protection.<br />
Generally, China’s pulp & paper industry has made a great technological <strong>ac</strong>hievement, <strong>th</strong>ough<br />
some problems should be solved when f<strong>ac</strong>ing <strong>th</strong>e next century.<br />
6.1.3 Evolution <strong>of</strong> energy efficiency in Chinese pulp & paper industry<br />
6.1.3.1 General situation <strong>of</strong> energy consumption<br />
The pulp & paper industry <strong>of</strong> China is <strong>th</strong>e biggest energy consuming industry among all light<br />
industries. Table 6.1.4 shows <strong>th</strong>e overall energy consumption <strong>of</strong> <strong>th</strong>e industry, while Table 6.1.5<br />
and Figure 6.1.6 show <strong>th</strong>e unit energy consumption <strong>of</strong> its major products. Table 6.1.6 shows <strong>th</strong>e<br />
unit energy consumption for 870 paper mills belonging to <strong>th</strong>e CLIC from 1985 to 1990.<br />
Table 6.1.4 Overall energy consumption by <strong>th</strong>e industry from 1985 to 1992<br />
Indicator Coal<br />
Electricity<br />
Total<br />
10,000 ton billion kWh 10,000 toe<br />
Year 1985 1990 1992 1985 1990 1992 1985 1990 1992<br />
Data<br />
Share in<br />
1251 1640 1787 8.09 11.98 13.97 847.5 1109 1240<br />
national total<br />
%<br />
Source: [11]<br />
1.53 1.55 1.57 1.96 1.92 1.84 1.69 2.13 1.74<br />
Table 6.1.5 Unit product energy consumption in <strong>th</strong>e paper industry<br />
Item Unit 1980 1985 1988 1989 1990<br />
Electricity consumption for wood KWh/to 1522 1588 1560 1566<br />
pulp<br />
n<br />
SOE consumption for total pulp toe/ton 0.419 0.406 0.445<br />
Electricity for newsprint KWh/to<br />
n<br />
556 565 568 583<br />
SOE for paper & paperboard toe/ton 0.99 0.60 0.57<br />
Integrated energy consumption toe/ton 1.257 0.910 0.805<br />
Source: [6,12], bo<strong>th</strong> SOE and oe are standard oil equivalent
62 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Table 6.1.6 Specific energy consumption <strong>of</strong> major products for 870 paper mills <strong>of</strong> CLIC<br />
Indicator Unit 1985 1988 1989 1990<br />
Integrated<br />
consumption<br />
specific energy toe/t 1.07 1.01 1.01<br />
Mechanical wood pulp kWh/t 1522 1588 1560 1566<br />
Newsprint<br />
Source: [1, 3]<br />
kWh/t 556 565 568 583<br />
Though integrated unit energy consumption has decreased in recent years, <strong>th</strong>e unit electricity<br />
consumption for mechanical wood pulp and newsprint increased on <strong>th</strong>e contrary.<br />
For <strong>th</strong>e same paper & paperboard products, specific energy consumption values <strong>of</strong> non-CLIC<br />
paper mills are generally higher <strong>th</strong>an <strong>th</strong>at <strong>of</strong> CLIC ones, except for <strong>th</strong>e township case. The reason<br />
for <strong>th</strong>e very low specific energy consumption <strong>of</strong> <strong>th</strong>e latter is <strong>th</strong>e low quality <strong>of</strong> its products and <strong>th</strong>e<br />
simple, crude equipment being employed. Table 6.1.7 gives a comparison <strong>of</strong> <strong>th</strong>e unit energy<br />
consumption <strong>of</strong> paper mills among various sectors.<br />
ton ce/ton(paper & paperboard)<br />
2.5<br />
2<br />
1.5<br />
1<br />
0.5<br />
0<br />
1981 1984 1985<br />
Year<br />
1990 1992<br />
Figure 6.1.6 Integrated energy consumption <strong>of</strong> <strong>th</strong>e paper industry in China<br />
Table 6.1.7 Specific energy consumption by various owners (1990)<br />
Item National CLIC Agricultural system Forest Military<br />
total Reclamation Township system system<br />
Production, Mt 13.72 7.71 0.38 5.23 0.10 0.30<br />
Energy consumption (103 toe)<br />
Specific energy consumption<br />
11086 7330 377 2982 99 299<br />
<strong>of</strong> paper & paper board, toe/t<br />
Source: [1]<br />
0.805 0.949 0.995 0.569 0.995 0.995
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 63<br />
From 1985 to 1990, energy consumption per 10,000 Yuan gross output volume (in 1980 fixed<br />
price) <strong>of</strong> paper industry wi<strong>th</strong>in CLIC system decreased from 3.93 toe/10,000 Yuan to 3.01<br />
toe/10,000 Yuan. The energy consumption elasticity was 0.28, and <strong>th</strong>e annual average energy<br />
saving rate was 5.33% during <strong>th</strong>e period. It should be noted <strong>th</strong>at <strong>th</strong>e decrease <strong>of</strong> energy<br />
consumption cannot be fully attributed to direct energy conservation via technology or process<br />
advances. Two aspects can be highlighted for <strong>th</strong>e decrease. One is <strong>th</strong>e change in product mix and<br />
<strong>th</strong>e emergence <strong>of</strong> new high value-added paper products. The o<strong>th</strong>er is <strong>th</strong>e change in raw material<br />
mix, i.e., grow<strong>th</strong> <strong>of</strong> imported commercial pulp and waste paper as secondary fibrous raw material.<br />
These two f<strong>ac</strong>tors enable <strong>th</strong>e paper industry to augment its production and output wi<strong>th</strong>out any<br />
proportional increase in energy demand.<br />
6.1.3.2 Major endeavors for <strong>th</strong>e progress in energy efficiency<br />
From <strong>th</strong>e above tables and Figure 6.1.6, it can be seen <strong>th</strong>at <strong>th</strong>e integrated energy consumption<br />
indicator decreased by 42.7% from 1981 to 1992 wi<strong>th</strong> an average annual reduction rate <strong>of</strong> 5.2%.<br />
Therefore, much energy conservation was obtained <strong>th</strong>roughout <strong>th</strong>is period. The main causes can<br />
be attributed to <strong>th</strong>e following:<br />
- Enhancement <strong>of</strong> enterprise energy management from all aspects including setting up a<br />
national energy conservation network, holding energy management/saving training<br />
workshops, issuing rated energy consumption norms for special paper products in<br />
August 1985 (four grades for a paper product: Testing Norm, Average Advanced Norm,<br />
Domestic Pr<strong>of</strong>essional Advanced Norm and International Advanced Norm).<br />
- Retr<strong>of</strong>itting some old and low efficiency boilers, remolding a batch <strong>of</strong> oil-fired boilers<br />
into coal-fired boilers (under <strong>th</strong>e stringent oil energy supply situation) and improving<br />
technical skills <strong>of</strong> operators.<br />
- Enhancement <strong>of</strong> <strong>th</strong>ermal insulating performance <strong>of</strong> steam tubes and digester equipment.<br />
- Popularizing and disseminating some energy saving equipment such as Electric Loci<br />
V<strong>ac</strong>uum Fans, Pan mills and double-paned mills, speed-adjustable electrical fans,<br />
electricity-saving appliances, etc..<br />
- By 1991, more <strong>th</strong>an sixty large scale pulp & paper mill cogeneration plants were installed<br />
wi<strong>th</strong> a total power cap<strong>ac</strong>ity <strong>of</strong> 473 MW. Of <strong>th</strong>ese, 422 MW cap<strong>ac</strong>ity belonged to <strong>th</strong>irty<br />
key enterprises. For comparison, cogeneration cap<strong>ac</strong>ity in 1949 was only 10 MW. In<br />
1990, power generation by cogeneration plants amounted to 1.65 billion kWh. At <strong>th</strong>e<br />
same time, newly-built large and/or medium scale paper mills had <strong>th</strong>eir own<br />
cogeneration plants [5].
64 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
- A number <strong>of</strong> technological transformations for paper making m<strong>ac</strong>hine parts had been<br />
implemented, including white liquor recovery, dryer condensate recovery, <strong>th</strong>ree-stage<br />
steam feed, etc..<br />
- Minicomputer-based systems had been primarily used for <strong>th</strong>e cooking process and<br />
automation control for constant moisture content <strong>of</strong> paper in <strong>th</strong>e paper making process.<br />
- Since 1980, much efforts have been made to popularize and disseminate energy-saving<br />
spray nozzles as well as white liquor circulation recovery. This has led to <strong>th</strong>e decrease in<br />
specific water consumption in <strong>th</strong>e paper making process. For example, utilization <strong>of</strong> a<br />
fan-pattern spray nozzle can bring about water savings <strong>of</strong> 18-20%. Adoption <strong>of</strong> white<br />
liquor circulating loop can enable specific water consumption to decrease from 200-300<br />
m 3 to 50 m 3 <strong>of</strong> water per ton <strong>of</strong> paper.<br />
6.1.3.3 Comparison <strong>of</strong> <strong>th</strong>e energy consumption <strong>of</strong> Chinese pulp & paper industry wi<strong>th</strong><br />
o<strong>th</strong>er countries<br />
The overall energy consumption level in China’s pulp and paper industry is much higher when<br />
compared to its foreign counterparts in spite <strong>of</strong> <strong>th</strong>e above <strong>ac</strong>hievements in energy conservation<br />
during <strong>th</strong>e last years.<br />
As for <strong>th</strong>e integrated unit energy consumption <strong>of</strong> paper & paperboard product, <strong>th</strong>e indicator in <strong>th</strong>e<br />
United States had decreased to 1.17 tce/ton <strong>of</strong> paper and paperboard (0.766 toe/t) as early as <strong>th</strong>e<br />
mid-70s[12], which means <strong>th</strong>at China's energy level lags some 20 years behind <strong>th</strong>at <strong>of</strong> <strong>th</strong>e USA.<br />
By <strong>th</strong>e end <strong>of</strong> <strong>th</strong>e 1970s, <strong>th</strong>e same indicator in industrialized countries generally went down to <strong>th</strong>e<br />
level <strong>of</strong> 1.15 - 1.22 tce/t (0.753-0.798 toe/t), which was only 64% or even less <strong>th</strong>an China's value at<br />
<strong>th</strong>e same time.[12] In 1989, integrated energy consumption for Japanese pulp & paper industry<br />
was 14.5 GJ/ton* or 0.495 tce/ton (0.324 toe/t), which was only 40% <strong>th</strong>at <strong>of</strong> China. A<br />
comparison <strong>of</strong> <strong>th</strong>e unit energy consumption <strong>of</strong> China and some developed countries, and <strong>th</strong>e<br />
world average level are shown in Figure 6.1.7 and Table 6.1.8.<br />
* 1 tce = 0.654 toe = 29.31 GJ and 1 toe = 44.76 GJ
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 65<br />
ton ce/ton(paper & paperboard)<br />
1.4<br />
1.2<br />
1<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0<br />
Advanced in<br />
Nor<strong>th</strong>Europe<br />
Australia England<br />
newsprint Newsprint newsprit (low<br />
(low limit)<br />
limit)<br />
England<br />
newsprint<br />
(up limit)<br />
USA<br />
newsprint<br />
Japan P.R.China<br />
Figure 6.1.7 Comparison <strong>of</strong> integrated energy consumption among various countries<br />
Table 6.1.8 Domestic and international integrated product energy consumption<br />
Minimum energy<br />
consumption<br />
toe/t<br />
Maximum energy<br />
consumption toe/t<br />
Average level<br />
toe/t<br />
China 0.818 1.113 1.010<br />
World 0.330 0.779 0.556<br />
6.1.3.4 Main reasons for <strong>th</strong>e low efficiency energy situation in <strong>th</strong>e paper industry<br />
There are many complex reasons for <strong>th</strong>e low energy efficiency in China. The most prominent<br />
among <strong>th</strong>em are identified as follows.<br />
First, <strong>th</strong>ere are more <strong>th</strong>an 10,000 paper enterprises, most <strong>of</strong> which are small in size (wi<strong>th</strong> an<br />
average per enterprise scale <strong>of</strong> 2550 ton/year), owned by diverse sectors and township industries.<br />
Most <strong>of</strong> <strong>th</strong>ese small paper mills use straw as raw material wi<strong>th</strong>out any recovery <strong>of</strong> ei<strong>th</strong>er valuable<br />
chemicals or <strong>th</strong>ermal energy. Such small scale pulp and paper mills are reputed not to be adopting<br />
alkali recovery processes, cogeneration, as well as o<strong>th</strong>er high-energy, high efficiency technologies.<br />
These mills are also not easily monitored for <strong>th</strong>eir energy consumption due to <strong>th</strong>e severe l<strong>ac</strong>k <strong>of</strong><br />
technical streng<strong>th</strong>. Moreover, many entrepreneurs do not care about <strong>th</strong>eir f<strong>ac</strong>tories' energy<br />
efficiency for some complex reasons.
66 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Second, wi<strong>th</strong> regard to large size paper mills, <strong>th</strong>ere still exists a big gap between <strong>th</strong>e most energy<br />
efficient enterprises and <strong>th</strong>e lowest ones. A survey conducted in 1986 in 32 key enterprises showed<br />
<strong>th</strong>at <strong>th</strong>e average integrated energy consumption was about 1.48 tce/t (0.969 toe/t). The indicator<br />
for <strong>th</strong>e most energy efficient enterprise was 0.78, which can compete wi<strong>th</strong> internationally advanced<br />
levels, while <strong>th</strong>e same for <strong>th</strong>e lowest one was 2.6 tce/t (1.70 toe/t), or <strong>th</strong>ree times higher <strong>th</strong>an <strong>th</strong>e<br />
former.[12]<br />
Third, as mentioned above, <strong>th</strong>ere were only 60 large size paper mills wi<strong>th</strong> cogeneration power<br />
plants among <strong>th</strong>e ten <strong>th</strong>ousand paper mills nationwide in 1990. For <strong>th</strong>e total 4500 MW power<br />
cap<strong>ac</strong>ity <strong>of</strong> electric equipment in <strong>th</strong>e sector, self-generation <strong>of</strong> power could only meet 10.5% <strong>of</strong><br />
electricity demand. It has been proven <strong>th</strong>at a cogeneration plant can do <strong>th</strong>e paper mill itself much<br />
good due to its greater and stable combined <strong>th</strong>ermal and power load. Once again, <strong>th</strong>e size <strong>of</strong> small<br />
paper mills is blamed for <strong>th</strong>e non-installation <strong>of</strong> cogeneration systems. [5]<br />
Four<strong>th</strong>, perhaps <strong>th</strong>e root cause <strong>of</strong> <strong>th</strong>e problem <strong>of</strong> low energy efficiency is <strong>th</strong>e low efficiency <strong>of</strong><br />
boilers used in <strong>th</strong>e paper mills. Despite some medium-pressure boilers installed in a few large size<br />
paper enterprises wi<strong>th</strong> a <strong>th</strong>ermal efficiency <strong>of</strong> 80%, <strong>th</strong>ose installed in myriad small paper mills have<br />
efficiencies as low as 60%[4]. On <strong>th</strong>e contrary, <strong>th</strong>e efficiency for industrial boilers in developed<br />
countries is wi<strong>th</strong>in <strong>th</strong>e range <strong>of</strong> 80-85%. Often, heat loss rates <strong>of</strong> <strong>th</strong>ermal network exceed 10%.<br />
Therefore, overall <strong>th</strong>ermal efficiency for China's pulp & paper enterprises might be lower <strong>th</strong>an<br />
30%, some even less <strong>th</strong>an 25%.[4]<br />
Fif<strong>th</strong>, most <strong>of</strong> <strong>th</strong>e high calorific wastewater and o<strong>th</strong>er associated energy carriers (bark, sawdust etc.)<br />
are abandoned wi<strong>th</strong>out recovery <strong>of</strong> relevant chemicals and for energy supply. For <strong>th</strong>e time being,<br />
<strong>th</strong>ere are only <strong>th</strong>ree paper mills (Jilin Pulp & Paper Mill, Jiamusi Pulp & Paper Mill and Wufu<br />
Eastern Pulp & Paper Mill) installed wi<strong>th</strong> waste recovery boilers in which bark, sawdust and wood<br />
chips are fired. Beside <strong>th</strong>e loss <strong>of</strong> energy, <strong>th</strong>e environment is polluted. In comparison, some<br />
Western European paper mills can provide 87% <strong>of</strong> energy for <strong>th</strong>eir whole pulping process by fully<br />
exploiting waste materials such as bark and bl<strong>ac</strong>k liquor.<br />
Six<strong>th</strong>, energy consumed for <strong>th</strong>e digestion process usually <strong>ac</strong>counts for 45% <strong>of</strong> <strong>th</strong>e total pulping and<br />
paper making process. Usually, continuous digestion process can save 40% <strong>of</strong> <strong>th</strong>e amount <strong>of</strong> steam<br />
compared wi<strong>th</strong> <strong>th</strong>e intermittent digestion process, whereby much <strong>th</strong>ermal energy savings can be<br />
obtained. Unfortunately, most digestion processes in China are intermittent ones except in rare<br />
cases. At present, <strong>th</strong>e best figure for pulping process in China is about 1.6 ton steam/ton <strong>of</strong> pulp.<br />
The same indicator for foreign countries is just 0.4-0.6 ton steam/ton <strong>of</strong> pulp. Most equipment<br />
used for cooking in foreign countries are ei<strong>th</strong>er <strong>th</strong>e continuous digestion process or <strong>th</strong>e lowenergy-consuming<br />
intermittent digestion (RDH).<br />
Seven<strong>th</strong>, cylinder m<strong>ac</strong>hines for paper making in China’s paper mills <strong>ac</strong>count for only 83% <strong>of</strong> <strong>th</strong>e<br />
total number <strong>of</strong> paper m<strong>ac</strong>hines wi<strong>th</strong> speeds <strong>of</strong> lower <strong>th</strong>an 200 m/min and wid<strong>th</strong>s <strong>of</strong> 1m to 2m. In
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 67<br />
comparison, <strong>th</strong>e wid<strong>th</strong> <strong>of</strong> Fourdrinier m<strong>ac</strong>hine is generally between 5-10m, wi<strong>th</strong> m<strong>ac</strong>hine speeds <strong>of</strong><br />
800-1200 m/min.<br />
Finally, as for <strong>th</strong>e fuel mix pertaining to <strong>th</strong>e pulp & paper industry <strong>of</strong> China, coal is <strong>th</strong>e dominant<br />
fuel <strong>ac</strong>counting for 95% <strong>of</strong> <strong>th</strong>e total. Most types <strong>of</strong> coal used are <strong>of</strong> low grade.<br />
6.1.4 Environmental externalities <strong>of</strong> <strong>th</strong>e pulp & paper industry in China<br />
6.1.4.1 Liquid, gaseous and solid pollutants<br />
The pulp & paper industry is a typical pollution intensive industry among all industries. The most<br />
serious externality is <strong>th</strong>e water pollution due to <strong>th</strong>e highly concentrated organic wastewater<br />
effluents. Table 6.1.9 shows <strong>th</strong>e amount <strong>of</strong> wastewater discharged from 2282 pulp & paper mills<br />
counted in 1993. BOD (biochemical oxygen demand) discharge by <strong>th</strong>e paper mills was 2.716<br />
billion tons, <strong>ac</strong>counting for 38.2% <strong>of</strong> national BOD discharge, holding <strong>th</strong>e first position among all<br />
industries in China. If all pulp & paper mills were taken into <strong>ac</strong>count, <strong>th</strong>e total wastewater amount<br />
discharged from <strong>th</strong>e industry would have re<strong>ac</strong>hed as high as 3 billion tons in 1992, <strong>ac</strong>counting for<br />
about one eigh<strong>th</strong> <strong>of</strong> national total wastewater amount, ranking <strong>th</strong>ird after <strong>th</strong>e chemical and ferrous<br />
industries.<br />
Table 6.1.9 Wastewater discharge and treatment by Chinese paper industry in 1993 (Mt)<br />
Number <strong>of</strong> enterprise<br />
counted<br />
Total<br />
wastewater<br />
discharged<br />
Discharge<br />
d directly<br />
to inland<br />
water body<br />
Discharged<br />
directly to<br />
sea<br />
Discharge<br />
d <strong>th</strong>rough<br />
treatment<br />
plant<br />
Wastewater<br />
under State<br />
Discharge<br />
Standards<br />
2282 pulp & paper mills 2158 1713 18 21.4 314<br />
All industries 21949 NA NA 17934 12049<br />
Share <strong>of</strong> pulp & paper<br />
industry<br />
9.8% – – 1.2‰ 2.6%<br />
Besides slag (coal combustion cinders and white silt from alkali recovery), dust and ash, pungent<br />
smell and noise have also <strong>th</strong>eir environmental imp<strong>ac</strong>ts. In 1992, slag and cinder discharged by <strong>th</strong>e<br />
paper industry rose to 4.8 million tons, 296,000 tons <strong>of</strong> SO 2, 267,000 tons <strong>of</strong> soot and dust, and<br />
2.34 million tons <strong>of</strong> CO 2.<br />
Table 6.1.10 shows some gaseous emissions from <strong>th</strong>e industry. It can be found <strong>th</strong>at two-<strong>th</strong>irds <strong>of</strong><br />
<strong>th</strong>e gaseous emissions are from fuel combustion in industrial boilers, and one-<strong>th</strong>ird is from <strong>th</strong>e<br />
production processes.
68 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Table 6.1.10 Gaseous emissions by pulp & paper industry in China in 1993<br />
Indicator<br />
Total<br />
gaseous<br />
emission<br />
s billion<br />
m3 Emissions<br />
from fuel<br />
combustio<br />
n billion<br />
m3 Emissions<br />
from<br />
production<br />
process<br />
billion m3 SO2 emissions<br />
104 Soot<br />
discharged<br />
t 104 Dust<br />
discharge<br />
d<br />
t<br />
104 t<br />
Pulp & Paper<br />
industry<br />
173.1 117.1 56.0 28.177 28.7497 3.9332<br />
All industries 9342 6004 3338 1292 880 617<br />
National 10960 1795 1416<br />
From Table 6.1.11, which shows <strong>th</strong>e water pollution discharge loads in China from 1980 to 1988, it<br />
can be seen <strong>th</strong>at specific water pollution loads (including BOD and SS) decreased by 33% to 36%.<br />
The reduction stemmed from alkali recovery, integrated exploitation <strong>of</strong> digested wastewater, use <strong>of</strong><br />
recycled white water as well as fiber recovery which were popularized and used in some large and<br />
medium scale pulp & paper mills. Never<strong>th</strong>eless, total water pollution amounts escalated gradually.<br />
Table 6.1.11 Estimation <strong>of</strong> <strong>th</strong>e total amount <strong>of</strong> water pollution and discharge load[9]<br />
Year Wastewater<br />
discharged<br />
BOD SS<br />
Unit 108<br />
m3/year<br />
m3/ton<br />
paper<br />
10,000<br />
ton/year<br />
kg/ton<br />
paper<br />
10,000<br />
ton/year<br />
kg/ton<br />
paper<br />
1980 27.6 516 125.5 235 120.3 225<br />
1985 33 362 143 157 146 160<br />
1988 40 315 190 150 192 151<br />
Note: BOD – Biochemical or Biological Oxygen Demand, SS – fiber, fillings suspensions<br />
6.1.4.2 Pollution from paper mill: a case <strong>of</strong> Qiqihar pulp & paper mill<br />
Considering <strong>th</strong>e 33 key large size pulp & paper mills belonging to <strong>th</strong>e China Light Industries<br />
Commission (CLIC), not all <strong>of</strong> <strong>th</strong>em are environmentally sound. For example, Qiqihar pulp &<br />
paper mill,[7,14] famous for its newsprint paper production, <strong>ac</strong>counted for 11.5% <strong>of</strong> <strong>th</strong>e national<br />
total newsprint paper production from 1954 to 1991. In 1991, its wastewater discharge was 70344 -<br />
77446 tons/day, from which <strong>th</strong>e COD (Chemical Oxygen Demand) discharge was 40.125 - 41.029<br />
tons/day, BOD discharge was 6.836 tons/day, SS was 25.821 - 3.3821 tons/day, emitted gaseous<br />
pollutant soot and dust was 4112 tons/year, SO2 was at 1133 tons/year, total amount <strong>of</strong> solid<br />
waste was 63331 tons/year, and <strong>th</strong>e strongest noise intensity was at 110 - 136 dB(A). A more<br />
detailed pollution situation <strong>of</strong> <strong>th</strong>e paper mill is shown in Table 6.1.12-a & b and Table 6.1.13.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 69<br />
Table 6.1.12-a Status <strong>of</strong> water pollution in Qiqihar pulp & paper mill (summer)<br />
Pollution source Pollutants Unit Amount Recept<strong>ac</strong>le<br />
water effluent m 3/d 51631<br />
White liquor COD cr kg/d 30101 oxidizing<br />
outlet BOD5 kg/d 4698 pond<br />
SS kg/d 19973<br />
water effluent m 3/d 19815<br />
Bl<strong>ac</strong>k liquor CODcr kg/d 10106 oxidizing<br />
outlet BOD5 kg/d 2140 pond<br />
SS kg/d 9348<br />
water effluent m 3/d 6000<br />
Ash outlet CODcr kg/d 822 oxidizing<br />
BOD5 kg/d - pond<br />
SS kg/d 4500<br />
Table 6.1.12-b Status <strong>of</strong> water pollution in Qiqihar pulp & paper mill (winter)<br />
Pollution source Pollutants Unit Amount Recept<strong>ac</strong>le<br />
water effluent m 3/d 44529<br />
White liquor CODcr kg/d 39197 oxidizing<br />
outlet BOD5 kg/d 4698 pond<br />
SS kg/d 11973<br />
water effluent m 3/d 19815<br />
Bl<strong>ac</strong>k liquor CODcr kg/d 10106 oxidizing<br />
outlet BOD5 kg/d 2140 pond<br />
SS kg/d 9348<br />
water effluent m 3/d 6000<br />
Ash outlet CODcr kg/d 822 oxidizing<br />
BOD5 kg/d pond<br />
SS kg/d 4500<br />
Table 6.1.13 Gaseous and solid pollution by Qiqihar pulp & paper mill<br />
Pollution source Pollutants Unit Amount Recept<strong>ac</strong>le<br />
Cogeneration smoke & soot t/year 3558-1015 atmosphere<br />
Kilns TSP t/year. 555 atmosphere<br />
SO2 t/year 119<br />
Alkali recovery workshop H2S mg/m3 ~90 near <strong>th</strong>e workshop<br />
Cogeneration Slag & Ash m3/year 50000 ash storage field<br />
Wood preparing bark m3/year 54 filler or<br />
workshop residential fuel<br />
Alkali recovery white silt and t/d 32.8 to lime kiln for<br />
workshop alkaline ash lime recovery
70 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
According to <strong>th</strong>e wastewater discharging norm for pulp & paper industry (GB3544-92), its total<br />
wastewater discharged was about two times greater <strong>th</strong>an <strong>th</strong>e set quota; COD was 1.7 - 2.0 times<br />
greater and SS was 1.5 - 2.9 times greater <strong>th</strong>an <strong>th</strong>e set quota. Much reductions should be <strong>ac</strong>hieved<br />
if all <strong>th</strong>e paper mills abide by <strong>th</strong>e set regulation. [7]<br />
6.1.4.3 Major causes <strong>of</strong> <strong>th</strong>e increasing pollution<br />
Recently, pulp & paperboard production rose rapidly. This could be attributed mainly to <strong>th</strong>e high<br />
increase in production <strong>of</strong> many small size straw-based township enterprises. This change resulted<br />
in bo<strong>th</strong> average unit enterprise scale decrease and overall technical level fall, because most <strong>of</strong> <strong>th</strong>em<br />
were furnished wi<strong>th</strong> low-technical-level equipment. O<strong>th</strong>er reasons are summarized as follows:<br />
- Indifference to environmental pollution from enterprises leaders to workers.<br />
- The share <strong>of</strong> non-wood fiber raw material is too large. For <strong>th</strong>e prevailing straw pulp<br />
pollution in China, <strong>th</strong>ere are no technically mature and economically feasible clean<br />
production and/or environment-protecting technologies available.<br />
- As for <strong>th</strong>e vast capital investment demand for clean production and environmental<br />
treatment in China's various paper mills, <strong>th</strong>ere are no special and definite financial<br />
channels as yet.<br />
- No stern environmental assessment is stipulated as an indispensable prerequisite to <strong>th</strong>e<br />
plant before <strong>th</strong>e construction <strong>of</strong> many new pulp and paper mills, especially <strong>th</strong>ose in rural<br />
townships.<br />
6.1.5 Potential for energy efficiency improvement and pollution abatement <strong>th</strong>rough<br />
technological changes<br />
From <strong>th</strong>e above analysis, it can be concluded <strong>th</strong>at <strong>th</strong>ere exists great potential for energy savings as<br />
well as environmental alleviation. The potentials identified can be summarized as follows:<br />
1. Adjustment <strong>of</strong> <strong>th</strong>e present structure <strong>of</strong> <strong>th</strong>e enterprises (scale), and development <strong>of</strong> a scaleeconomy<br />
<strong>of</strong> large cap<strong>ac</strong>ity enterprises and/or groups.<br />
There is a worldwide development trend in pulp & paper industry for <strong>th</strong>e time being: many pulp &<br />
paper mills ally toge<strong>th</strong>er to pursue stronger market competitive ability. In Japan, two leading pulp<br />
& paper companies, e<strong>ac</strong>h <strong>of</strong> which had a cap<strong>ac</strong>ity more <strong>th</strong>an 1 million tons per year have merged<br />
into a super-enterprise recently.<br />
As mentioned above, China's average size per enterprise is much lower compared to its foreign<br />
counterparts, which results in a series <strong>of</strong> problems <strong>th</strong>at encumber its energy efficiency as well as<br />
environment-friendly development. It is a common consensus among Chinese paper experts <strong>th</strong>at
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 71<br />
construction <strong>of</strong> large size paper mills installed wi<strong>th</strong> modern technological equipment is <strong>of</strong> great<br />
importance. Many township mills and o<strong>th</strong>er little enterprises should be merged into bigger ones for<br />
higher productivity, higher energy efficiency and more sound environmental compatibility.<br />
Moreover, larger scale paper mills will pave <strong>th</strong>e way for a series <strong>of</strong> subsequent measures to deal<br />
wi<strong>th</strong> existing problems.<br />
2. Changing raw material composition <strong>of</strong> China's current pulp production, raising <strong>th</strong>e share <strong>of</strong><br />
wood pulp and waste-paper pulp.<br />
According to statistics on straw pulp production, China has been <strong>th</strong>e first in <strong>th</strong>e world for years. It<br />
had been found, however, <strong>th</strong>at <strong>th</strong>e dominant fr<strong>ac</strong>tion <strong>of</strong> straw pulp production is also a barrier to<br />
energy efficiency improvement and pollution abatement. In <strong>th</strong>e United States and Japan, wood<br />
pulp's fr<strong>ac</strong>tion in <strong>th</strong>e total pulp production was more <strong>th</strong>an 99% (Table 6.1.14):<br />
Table 6.1.14 Global pulp production cap<strong>ac</strong>ity and share <strong>of</strong> wood pulp (FAO, 1987)<br />
Country Total production cap<strong>ac</strong>ity<br />
(10 3 Wood pulp's share in national<br />
ton)<br />
total (%)<br />
USA 53,677 99.3<br />
Japan 12,675 95.1<br />
former USSR 12,408 99.9<br />
China 10,679 23.9<br />
Brazil 4,375 93.4<br />
India 2,790 26.9<br />
France 2,310 99.1<br />
Exploitation <strong>of</strong> wood resources for boosting wood pulp production will not only raise <strong>th</strong>e quality<br />
<strong>of</strong> <strong>th</strong>e final paper products, it will also create a favorable condition for “associated biomass energy”<br />
recovery utilization. Moreover, all kinds <strong>of</strong> mature pollution abatement technologies pertaining to<br />
<strong>th</strong>e wood pulp process can be implemented easily.<br />
To reduce fiber raw material consumption in pulp production, an effective way is to enhance waste<br />
paper recovery. It has been proven <strong>th</strong>at wastepaper-derived pulp uses only around 1/4 or 1/3 <strong>of</strong><br />
<strong>th</strong>e energy claimed by <strong>th</strong>e wood-derived pulp. In 1988, China's waste-paper pulp (including<br />
imported waste paper) <strong>ac</strong>counting for 22.5% <strong>of</strong> <strong>th</strong>e total pulp production, implied a big potential<br />
when compared to <strong>th</strong>e same indicators <strong>of</strong> Japan and <strong>th</strong>e European Union (50% and 48%<br />
respectively). Exploitation <strong>of</strong> waste paper for pulp production not only reduces consumption <strong>of</strong><br />
energy and o<strong>th</strong>er resources, but also improves <strong>th</strong>e quality <strong>of</strong> <strong>th</strong>e environment.
72 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
3. Technological reform and renovation on outdated boilers.<br />
There are many old industrial coal-fired boilers wi<strong>th</strong> a total cap<strong>ac</strong>ity <strong>of</strong> more <strong>th</strong>an 14,000 tons/h in<br />
<strong>th</strong>e Chinese paper industry, and most <strong>of</strong> <strong>th</strong>em have efficiencies lower <strong>th</strong>an 60% or even 50%. This<br />
status indicates a great potential for energy savings <strong>th</strong>rough <strong>th</strong>e improvement <strong>of</strong> <strong>th</strong>e boiler<br />
efficiency.<br />
Combining technical renovation <strong>of</strong> some appropriate boilers and simple elimination <strong>of</strong> some is a<br />
better appro<strong>ac</strong>h for efficiency improvement. There exist many mature and technical-economically<br />
feasible processes which can be used for boiler renovation. For example, <strong>th</strong>e efficiency <strong>of</strong> small<br />
boilers wi<strong>th</strong> a cap<strong>ac</strong>ity <strong>of</strong> less <strong>th</strong>an 1 ton/h can be upgraded from 45% to 60% by a series <strong>of</strong><br />
renovations. For boilers wi<strong>th</strong> a cap<strong>ac</strong>ity between 1-4 tons/h, <strong>th</strong>e efficiency can be raised even to<br />
75% by technical renovation at a lower cost. Besides <strong>th</strong>is, boosting workers’ operational skill is<br />
also important.<br />
4. Development <strong>of</strong> cogeneration<br />
Cogeneration is a very useful technology for efficiency improvement in a pulp & paper mill, which<br />
can provide <strong>th</strong>ermal energy and electricity for its various processes. Compared to separate heat and<br />
power generation, it can get a prominent energy conservation effect <strong>of</strong> more <strong>th</strong>an 20%. As a rule,<br />
any paper mill which owns two or more sets <strong>of</strong> boilers wi<strong>th</strong> unit cap<strong>ac</strong>ity <strong>of</strong> more <strong>th</strong>an 10 t/h<br />
should build its corresponding cogeneration plant. Chinese experts estimated <strong>th</strong>at [8] total<br />
cogeneration installed cap<strong>ac</strong>ity in <strong>th</strong>e paper industry may be as much as 1600 MW by <strong>th</strong>e year<br />
2000. In 1991, total cogeneration cap<strong>ac</strong>ity was just 473 MW. The energy saving potential by<br />
cogeneration in <strong>th</strong>e Chinese paper industry will re<strong>ac</strong>h more <strong>th</strong>an 2 million tce (1.31 million toe) by<br />
2000 if 1600 MW installed cogeneration cap<strong>ac</strong>ity can be realized. The potential for cogeneration,<br />
<strong>th</strong>erefore, is great.<br />
5. Recovery <strong>of</strong> waste liquors and o<strong>th</strong>er associated energy carriers such as digested bl<strong>ac</strong>k liquor,<br />
bark, and sawdust.<br />
Recovery <strong>of</strong> associated energy carriers such as bl<strong>ac</strong>k liquor is <strong>of</strong> great benefit bo<strong>th</strong> for energy<br />
savings and for environmental protection. A ton <strong>of</strong> dried solid remnant <strong>of</strong> bl<strong>ac</strong>k liquor in <strong>th</strong>e<br />
process <strong>of</strong> sulfate pulping can provide <strong>th</strong>ermal energy <strong>of</strong> 0.43~0.49 tce (0.28 toe ~ 0.32 toe). In<br />
<strong>th</strong>e paper industry <strong>of</strong> developed countries, energy supply from associated energy carriers such as<br />
bl<strong>ac</strong>k liquor and bark <strong>ac</strong>count for a remarkable share. For instance, bl<strong>ac</strong>k liquor and bark supplied<br />
37.3% and 4.3%, respectively, <strong>of</strong> <strong>th</strong>e total paper industry energy demand in <strong>th</strong>e USA in <strong>th</strong>e early<br />
1980s. In Finland and Sweden, <strong>th</strong>e two items toge<strong>th</strong>er could meet more <strong>th</strong>an 50% <strong>of</strong> <strong>th</strong>e total<br />
energy demand. In some cases, even <strong>th</strong>e total energy demand by all processes can be met fully by<br />
recovery <strong>of</strong> bl<strong>ac</strong>k liquor and bark.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 73<br />
It is estimated <strong>th</strong>at <strong>th</strong>e total bl<strong>ac</strong>k liquor <strong>of</strong> <strong>th</strong>e industry can provide at least 3 million toe based on<br />
1990’s conditions. In comparison, <strong>th</strong>e level <strong>of</strong> wastewater recovery and utilization in China lags<br />
behind. At present, alkaline pulp cap<strong>ac</strong>ity wi<strong>th</strong> bl<strong>ac</strong>k liquor recovery is only 1.2 million tons,<br />
<strong>ac</strong>counting for 41% <strong>of</strong> <strong>th</strong>e total alkaline pulping cap<strong>ac</strong>ity nationwide. Most <strong>of</strong> <strong>th</strong>e paper mills do<br />
not have <strong>th</strong>e f<strong>ac</strong>ilities to exploit ei<strong>th</strong>er bl<strong>ac</strong>k liquor or bark to recover chemicals and <strong>th</strong>ermal<br />
energy. It is projected by CLIC <strong>th</strong>at if 1.2 million newly-added alkaline pulp cap<strong>ac</strong>ity wi<strong>th</strong> bl<strong>ac</strong>k<br />
liquor recovery is realized by 2000, <strong>th</strong>en 130,000 toe energy can be saved, and 450,000 tons caustic<br />
soda can be recycled while reducing BOD discharge by 250,000 tons.<br />
Combustible waste residue from large scale wood pulp mills alone amounts to 240,000 ton/year.<br />
As only <strong>th</strong>ree mills are installed wi<strong>th</strong> waste boilers firing <strong>th</strong>ese waste solid, <strong>th</strong>ere is an immense<br />
potential for energy efficiency improvement and environmental protection.<br />
6. To adopt advanced pulp and paper making technologies bo<strong>th</strong> for paper mills modernization<br />
and for building new large scale paper mills.<br />
Generally, <strong>th</strong>e energy consumed is distributed among all production processes as follows: 2% for<br />
wood material preparation, 46% for pulping (digestion, cleansing and alkali recovery), 4% for<br />
ble<strong>ac</strong>hing, 43% for paper shaping, 5% for paper processing. Among <strong>th</strong>e pulping processes,<br />
digestion <strong>ac</strong>counts for 97% <strong>of</strong> energy demand. Attention should be given <strong>th</strong>erefore to <strong>th</strong>e two<br />
energy-consuming processes, digestion and paper making.<br />
There exist two digestion processes: continuous digestion process and intermittent digestion.<br />
Compared to <strong>th</strong>e latter, <strong>th</strong>e former can avoid steam load fluctuation, <strong>th</strong>us reducing steam<br />
consumption by 40%. Continuous digestion process should be recommended to repl<strong>ac</strong>e<br />
intermittent one. At present, medium or small size continuous digestion equipment can be made in<br />
China, and a number <strong>of</strong> such equipment have already been commissioned. Moreover, a new lowenergy,<br />
cold-spouting intermittent digestion process (RDH) invented abroad is found to save 50%<br />
or more steam while raising productivity by 10-15% when compared to <strong>th</strong>e conventional<br />
intermittent digestion process. This new process can <strong>th</strong>erefore find a promising market in China,<br />
<strong>th</strong>ough <strong>th</strong>e use <strong>of</strong> such technology is not yet realized in <strong>th</strong>e country. Additionally, <strong>th</strong>e direct<br />
heating process for digestion should be substituted by <strong>th</strong>e indirect heating process since <strong>th</strong>e former<br />
consumes 15-20% more energy <strong>th</strong>an <strong>th</strong>e latter.<br />
Ano<strong>th</strong>er process which should also be given attention for energy savings is <strong>th</strong>e paper making stage.<br />
There are a number <strong>of</strong> feasible technological transformation me<strong>th</strong>ods for comprehensive energyrelated<br />
improvement <strong>of</strong> <strong>th</strong>e paper m<strong>ac</strong>hines. Medium speed Fourdrinier m<strong>ac</strong>hines can substitute<br />
existing cylinder m<strong>ac</strong>hines. The drying ability <strong>of</strong> <strong>th</strong>e m<strong>ac</strong>hines can also be boosted by polyester<br />
former, new pulp feeder and new drying apparatus. High intensity multi-press can be used in<br />
m<strong>ac</strong>hine press parts to raise wet paper dryness from <strong>th</strong>e current 32%-38% to 48%-50%. It has<br />
been proven <strong>th</strong>at reduction <strong>of</strong> 1% <strong>of</strong> moisture content <strong>of</strong> wet paper before drying can save 5% <strong>of</strong><br />
<strong>th</strong>e steam consumption for drying. The dryness <strong>of</strong> wet paper in Chinese paper mills is usually
74 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
around 30%, while <strong>th</strong>at <strong>of</strong> western countries is more <strong>th</strong>an 50%. Some technical measures to raise<br />
<strong>th</strong>ermal efficiency for drying include multi-stage steam feed, whole-sealed cover, recovery <strong>of</strong><br />
exhaust heat from its cover, etc. Computer-controlled steam feed for dry oven in some foreign<br />
countries also proved to be a useful way to save steam consumption. Computer-based constant<br />
moisture control systems should be disseminated in large or medium-size key paper mills. It is<br />
estimated <strong>th</strong>at specific energy consumption <strong>of</strong> paper m<strong>ac</strong>hines would be reduced by 30% <strong>th</strong>rough<br />
<strong>th</strong>e above-mentioned technologies. If 20% <strong>of</strong> <strong>th</strong>e existing paper m<strong>ac</strong>hines are retr<strong>of</strong>itted by <strong>th</strong>e<br />
year 2000, 650,000 toe can be conserved.<br />
7. Application <strong>of</strong> electricity-saving equipment for technical renovation, repl<strong>ac</strong>ement <strong>of</strong> outmoded<br />
appliances and dissemination <strong>of</strong> computer-controlled automation processes.<br />
The performance <strong>of</strong> electrical equipment directly affects <strong>th</strong>e electricity consumption <strong>of</strong> <strong>th</strong>e whole<br />
paper mill. Some available low-electricity-consuming equipment such as double-panned mill, Loci<br />
electric fan, axial-flow fan and speed-adjustable electric motor have better electricity saving effects<br />
compared to <strong>th</strong>eir respective old generation equipment. For instance, <strong>th</strong>e repl<strong>ac</strong>ement <strong>of</strong> variable<br />
frequency- speed-adjustable electric motor could save electricity by some 30% in most cases, while<br />
its cost could be paid b<strong>ac</strong>k in a few years. Here, existing barriers in <strong>th</strong>e Chinese case are mainly<br />
incentives and initial investments.<br />
On <strong>th</strong>e o<strong>th</strong>er side, computer controlled automation process may bring 10% steam reduction for<br />
<strong>th</strong>e process <strong>of</strong> pulping and 15% energy savings for paper shaping process in <strong>th</strong>e Chinese<br />
context.[12]<br />
8. For environmental protection, especially water pollution control, challenges and opportunities<br />
exist toge<strong>th</strong>er. Potential for pollution abatement includes:<br />
- For <strong>th</strong>e alkali pulping process, alkali recovery rates <strong>of</strong> various raw material-based mills<br />
can be increased to various levels: 90% alkali recovery rate for wood pulp, 80% for<br />
bamboo/bagasse pulp, and 70% for wheat straw pulp can be re<strong>ac</strong>hed.<br />
- For <strong>th</strong>e <strong>ac</strong>id process, efforts should be made to integrate exploitation <strong>of</strong> wastewater to<br />
produce adhesives, alcohol by products, etc.<br />
- For ammonium bisulfite pulp, wastewater can be used for agricultural irrigation & farm<br />
fertilizer. Recovery exploitation rate <strong>of</strong> wastewater for <strong>th</strong>is process can increase to 60%<br />
or higher.<br />
9. There is still a great potential for water conservation by improving water recycle utilization rate.<br />
Current white liquor recovery rate <strong>of</strong> paper m<strong>ac</strong>hine is 30%, while <strong>th</strong>e dryer condensate recovery<br />
rate is 50%
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 75<br />
10. Enhancement <strong>of</strong> pulp & paper industry pr<strong>of</strong>essional management, effective implementation <strong>of</strong><br />
existing regulations relevant to energy consumption and environmental protection issues.<br />
6.1.6 Status <strong>of</strong> application <strong>of</strong> new technologies<br />
Because most paper mills in China do not belong to <strong>th</strong>e CLIC, <strong>th</strong>ere is no strong au<strong>th</strong>ority or<br />
administrative department responsible for <strong>th</strong>e pr<strong>of</strong>essional management <strong>of</strong> <strong>th</strong>e pulp & paper<br />
industry. Much data concerning <strong>th</strong>e status <strong>of</strong> <strong>th</strong>e application <strong>of</strong> new technologies are not available.<br />
Following is an example <strong>of</strong> application <strong>of</strong> Alkali Recovery (AR) process in China:<br />
This technology is reckoned by <strong>th</strong>e industry to be <strong>th</strong>e key appro<strong>ac</strong>h for environmental control. By<br />
<strong>th</strong>e end <strong>of</strong> 1992, <strong>th</strong>ere were 63 paper mills installed wi<strong>th</strong> alkali recovery f<strong>ac</strong>ilities. Total alkali<br />
recovery cap<strong>ac</strong>ity hit 450,000 tons/year, while <strong>ac</strong>tual alkali recovery amount was 380,000<br />
tons/year. By <strong>th</strong>e AR process, about 400,000 tons <strong>of</strong> organic pollutants were refined. The AR<br />
rates in large size wood pulp mills re<strong>ac</strong>hed 90%, and in medium cap<strong>ac</strong>ity wood pulp mills, 75-80%.<br />
AR rate in large size straw pulp mills was 70% or so, medium size straw ones, 50-60%. There was<br />
about 1.2 million tons/year pulping cap<strong>ac</strong>ity matched wi<strong>th</strong> alkali recovery f<strong>ac</strong>ilities in 1992,<br />
<strong>ac</strong>counting for 41.4% <strong>of</strong> <strong>th</strong>e total 2.9 million tons/year pulping cap<strong>ac</strong>ity which needed <strong>th</strong>e<br />
technology (Table 6.1.15).<br />
Figure 6.1.8 shows <strong>th</strong>e alkali recovery evolution during <strong>th</strong>e decade from 1980 to 1990. It can be<br />
found <strong>th</strong>at overall alkali recovery and wood pulp alkali recovery kept similar increasing trends, wi<strong>th</strong><br />
annual grow<strong>th</strong> rates <strong>of</strong> 5.3% and 5.9%, respectively. Meanwhile, recovery <strong>of</strong> straw pulp alkali<br />
increased from 54,200 tons to 73,000 tons.<br />
Table 6.1.15 Status <strong>of</strong> AR utilization in China in 1992<br />
Alkali-based pulp Wood pulp Straw pulp<br />
Pulping cap<strong>ac</strong>ity wi<strong>th</strong> AR, Mt 1.2 0.80 0.40<br />
Pulping cap<strong>ac</strong>ity demanding AR, Mt 2.9 0.90 2.00<br />
Diffusion rate % 41.4 88.9 20<br />
AR rate % 22.6 70 6<br />
Wi<strong>th</strong> regards to <strong>th</strong>e total amount <strong>of</strong> alkali recovery, <strong>th</strong>e wood pulp mills’ situation was generally<br />
better <strong>th</strong>an <strong>th</strong>at <strong>of</strong> <strong>th</strong>e straw pulp mills. Figure 6.1.9 shows <strong>th</strong>e alkali recovery rates <strong>of</strong> <strong>th</strong>e situation<br />
in <strong>th</strong>e two pulp mills. Alkali recovery rate in <strong>th</strong>e wood pulp mills exceeded 60% in 1990. In <strong>th</strong>e<br />
straw pulp case, <strong>th</strong>e indicator was maintained at lower <strong>th</strong>an 10%. If <strong>th</strong>ose straw pulp mills outside<br />
<strong>th</strong>e CLIC (which <strong>of</strong>ten consumed alkali wi<strong>th</strong>out recovery ) were taken into <strong>ac</strong>count, however, <strong>th</strong>e<br />
real indicator <strong>of</strong> alkali recovery for whole straw pulp case should be lower <strong>th</strong>an 6% (Figure 6.1.9).
76 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
1000 ton<br />
400<br />
350<br />
300<br />
250<br />
200<br />
150<br />
100<br />
50<br />
0<br />
Total AR<br />
Wood Pulp AR<br />
Straw Pulp AR<br />
1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1992<br />
Figure 6.1.8 Alkali recovery by wood pulp and straw pulp from 1980 to 1990<br />
Percent<br />
70<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
Total AR rate<br />
Wood Pulp AR<br />
rate<br />
Straw pulp AR<br />
rate<br />
Year<br />
0<br />
1980 1981 1982 1983 1984 1985<br />
Year<br />
1986 1987 1988 1989 1990<br />
Figure 6.1.9 National m<strong>ac</strong>ro alkali recovery rates vs. year<br />
Since 1980, some important alkali recovery projects had been completed in large or medium size<br />
wood pulp mills such as <strong>th</strong>e Jiamusi Paper Mill, Jilin Paper Mill, Zhalandun Pulp & Paper Mill,<br />
Helongjiang Paper Mill, Yalujiang Paper Mill, Nanping Paper Mill and Qingzhou Paper Mill. At <strong>th</strong>e<br />
same time, technical transformations to large size straw pulp mills had also been made successfully.<br />
For instance, plate membranous concentrating vaporizers had been added into alkali recovery<br />
systems in Zhenjing Pulp & Paper Mill, Yueyang and Liujing Paper Mills. In a few cases, technical<br />
transformation and cap<strong>ac</strong>ity extension for alkali recovery in medium or small size straw pulp mills<br />
had been made wi<strong>th</strong> satisfying techno-economic effects, as in <strong>th</strong>e case <strong>of</strong> <strong>th</strong>e Guigang, Shanghai<br />
Songjiang Pulp & Paper Mills, etc.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 77<br />
Unfortunately, alkali recovery situation for most medium and small size straw pulp mills (wi<strong>th</strong><br />
cap<strong>ac</strong>ity <strong>of</strong> 15-35 tons pulp/day) was problematic due to reasons such as small economies <strong>of</strong> scale,<br />
low technical equipment installation, poor operation management as well as immature technologies<br />
available for bl<strong>ac</strong>k liquor treatment in straw pulp mills.<br />
By <strong>th</strong>e end <strong>of</strong> 1994, <strong>th</strong>ere were 73 AR projects wi<strong>th</strong> a total AR cap<strong>ac</strong>ity <strong>of</strong> 370,000 tons/year. Of<br />
<strong>th</strong>ese, 37 projects wi<strong>th</strong> a total AR cap<strong>ac</strong>ity <strong>of</strong> 120,000 tons/year were built but not commissioned,<br />
and 36 projects <strong>of</strong> total AR cap<strong>ac</strong>ity <strong>of</strong> 250,000 ton/year were under construction. By <strong>th</strong>e end <strong>of</strong><br />
1995, <strong>th</strong>ere will be a total <strong>of</strong> 30 paper mills installed wi<strong>th</strong> AR f<strong>ac</strong>ilities wi<strong>th</strong> a total AR cap<strong>ac</strong>ity <strong>of</strong><br />
820,000 tons/year.<br />
During <strong>th</strong>e last decades, <strong>th</strong>e AR cap<strong>ac</strong>ity wi<strong>th</strong> an annual grow<strong>th</strong> rate <strong>of</strong> 5.3% still lagged behind<br />
<strong>th</strong>at <strong>of</strong> <strong>th</strong>e paper & paperboard at 15% and <strong>th</strong>e pulp grow<strong>th</strong> rate <strong>of</strong> 13.7% during <strong>th</strong>e same period.<br />
This <strong>th</strong>erefore suggests <strong>th</strong>at more alkali is to be consumed to meet faster demand.<br />
For improvement <strong>of</strong> <strong>th</strong>e AR rate and wastewater integrated exploitation, wastewater abstr<strong>ac</strong>tion is<br />
<strong>th</strong>e primary process to be solved. Several hundreds <strong>of</strong> domestically-developed belt pulp scrubbers<br />
have been built since <strong>th</strong>e 1970s. Some large size paper mills also imported new high-efficiency pulp<br />
scrubbers. In a Guangzhou paper mill, where an imported advanced pulp scrubber was installed,<br />
<strong>th</strong>e AR was boosted to more <strong>th</strong>an 80%.<br />
As for many AR processes concerning straw pulp production and o<strong>th</strong>er digested wastewater<br />
recovery technologies, an eminent problem in <strong>th</strong>e Chinese situation is how to commercialize<br />
and/or disseminate <strong>th</strong>e results <strong>of</strong> <strong>th</strong>e studies in paper mills.<br />
6.1.7 Conclusions<br />
From <strong>th</strong>e above discussion, some main conclusions concerning <strong>th</strong>e pulp & paper industry in<br />
China can be briefly summarized as follows:<br />
- The pulp & paper industry <strong>of</strong> China is a fast developing industry, and currently ranks<br />
<strong>th</strong>ird in <strong>th</strong>e world. It could probably catch up wi<strong>th</strong> Japan to become <strong>th</strong>e second largest<br />
producer in <strong>th</strong>e world by 2000.<br />
- The pulp & paper industry <strong>of</strong> China is a highly energy-intensive and polluting industry,<br />
and is particularly blamed for water pollution.<br />
- China's integrated energy consumption indicator in <strong>th</strong>e pulp & paper industry is 2.45<br />
times as high as <strong>th</strong>at <strong>of</strong> Japan, 1.45 times as high as <strong>th</strong>at <strong>of</strong> USA. Therefore, its energy<br />
efficiency is much lower.
78 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
- Due to <strong>th</strong>e l<strong>ac</strong>k <strong>of</strong> wastewater recovery, exploitation and treatment technologies and/or<br />
measures, <strong>th</strong>e industry is responsible for 1/8 <strong>of</strong> <strong>th</strong>e national wastewater discharge, and<br />
more <strong>th</strong>an 1/3 <strong>of</strong> <strong>th</strong>e national BOD discharge. Thus, it is urgent to curb <strong>th</strong>e rampant<br />
environmental damaging behavior <strong>of</strong> <strong>th</strong>e pulp & paper industry.<br />
- There exists a great potential for energy efficiency improvement and environmental<br />
pollution mitigation from <strong>th</strong>e industry <strong>th</strong>rough a number <strong>of</strong> technical measures,<br />
including technological renovation and substitution for existing processes;<br />
transformation <strong>of</strong> existing paper mills; improvement <strong>of</strong> boiler efficiency; installation <strong>of</strong><br />
cogeneration; recovery <strong>of</strong> wastewater and o<strong>th</strong>er associated energy carriers (bark,<br />
sawdust); digestion process repl<strong>ac</strong>ement; computed-based automation etc.<br />
- From <strong>th</strong>e viewpoint <strong>of</strong> national m<strong>ac</strong>ro-system, enhancement <strong>of</strong> waste paper recycling,<br />
reshaping <strong>of</strong> enterprise scales, as well as <strong>th</strong>e change <strong>of</strong> raw materials for pulping should<br />
help in fur<strong>th</strong>er improvement and pollution abatement.<br />
- Consolidating pulp & paper pr<strong>of</strong>essional management and tightening <strong>th</strong>e<br />
implementation <strong>of</strong> existing pollution control regulations, as well as even legislating<br />
appropriate laws for discharge norm from paper mill are urgently needed.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 79<br />
6.2 COUNTRY REPORT: INDIA<br />
6.2.1 Introduction<br />
The paper industry in India has been established for over a century, wi<strong>th</strong> four paper manuf<strong>ac</strong>turing<br />
units initially in operation wi<strong>th</strong> an annual output <strong>of</strong> 20,000 tons. From an installed cap<strong>ac</strong>ity <strong>of</strong><br />
137,000 tons in <strong>th</strong>e year 1951, <strong>th</strong>e paper industry has grown during <strong>th</strong>e last four decades to an<br />
installed cap<strong>ac</strong>ity <strong>of</strong> 3,463,000 tons <strong>of</strong> paper and paperboard, and 300,000 tons <strong>of</strong> newsprint. The<br />
development <strong>of</strong> India’s paper industry centered on bamboo for raw material, ra<strong>th</strong>er <strong>th</strong>an wood as<br />
in o<strong>th</strong>er countries. Wi<strong>th</strong> bamboo resources falling short <strong>of</strong> <strong>th</strong>e requirement due to <strong>th</strong>e short term<br />
planning adapted <strong>th</strong>en, <strong>th</strong>e use <strong>of</strong> tropical hardwood started in <strong>th</strong>e 1960s. Until <strong>th</strong>e start <strong>of</strong> <strong>th</strong>e<br />
70s, <strong>th</strong>e paper industry had been forest-based and industrial units were integrated wi<strong>th</strong> pulp, paper<br />
and chemical recovery systems.<br />
Being highly capital-intensive, new investments were not for<strong>th</strong>coming at <strong>th</strong>e desired levels.<br />
Anticipating a shortage <strong>of</strong> paper in <strong>th</strong>e 1960s, a crash program for <strong>th</strong>e expansion <strong>of</strong> <strong>th</strong>e industry<br />
was devised, under which, second-hand plants and m<strong>ac</strong>hinery were allowed to be imported.<br />
The number <strong>of</strong> units in <strong>th</strong>e process increased from 25 in 1960-1961 to <strong>th</strong>e current 340 units. Most<br />
<strong>of</strong> <strong>th</strong>e small paper mills are ei<strong>th</strong>er agro-based or waste paper-based. At present, 29 units wi<strong>th</strong> a<br />
cap<strong>ac</strong>ity <strong>of</strong> 1,485,000 tons, representing 43% <strong>of</strong> <strong>th</strong>e installed cap<strong>ac</strong>ity for paper and paper board,<br />
rely on forest-based raw materials. Eighty-nine units wi<strong>th</strong> a cap<strong>ac</strong>ity <strong>of</strong> 974,000 tons, representing<br />
28% <strong>of</strong> <strong>th</strong>e installed cap<strong>ac</strong>ity, are based on agricultural residues. These units use imported pulp<br />
and recycled fiber as well. Added to <strong>th</strong>ese are some 22 units wi<strong>th</strong> a cap<strong>ac</strong>ity <strong>of</strong> 1,004,000 tons,<br />
representing 29% <strong>of</strong> <strong>th</strong>e installed cap<strong>ac</strong>ity, which are largely dependent on imported recycled<br />
fibers.<br />
The effective cap<strong>ac</strong>ity utilization <strong>of</strong> bamboo and wood-based units is 95%, 80% for agro-based<br />
units, 63% for recycled fiber-based units, wi<strong>th</strong> an average effective cap<strong>ac</strong>ity utilization <strong>of</strong> 82%<br />
(Figure 6.2.1). The overall cap<strong>ac</strong>ity utilization in relation to installed cap<strong>ac</strong>ity is 62%.<br />
The demand for paper and paperboard by <strong>th</strong>e turn <strong>of</strong> <strong>th</strong>e century shall be reckoned in terms <strong>of</strong> <strong>th</strong>e<br />
development phase which has already started. The per capita consumption <strong>of</strong> newsprint paper,<br />
currently at 2.4 kg, shall increase to 4.5 kg by <strong>th</strong>e year 2000 (Figure 6.2.2). The demand for paper<br />
and paperboard products would vary from <strong>th</strong>e p<strong>ac</strong>kaging to newsprints, and o<strong>th</strong>ers.<br />
6.2.2 Technological trajectory <strong>of</strong> <strong>th</strong>e Indian paper industry<br />
6.2.2.1 Structure <strong>of</strong> <strong>th</strong>e paper industry<br />
At <strong>th</strong>e start <strong>of</strong> <strong>th</strong>e 1950s, <strong>th</strong>e average production size <strong>of</strong> <strong>th</strong>e paper mills was only 8,000 t/year.<br />
Integrated paper mills based on forest raw materials set up during 1955-1960 resulted in an<br />
increase in <strong>th</strong>e average unit size to 16,000 t/year. In <strong>th</strong>e next decades, additional cap<strong>ac</strong>ity was
80 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
mostly due to <strong>th</strong>e expansion <strong>of</strong> existing mills and commissioning <strong>of</strong> small paper mills, but <strong>th</strong>e<br />
average size declined to 13,500 t/year. During 1970-1980, al<strong>th</strong>ough 8 large integrated mills wi<strong>th</strong><br />
production sizes <strong>of</strong> 20,000 t/year were commissioned, <strong>th</strong>e added cap<strong>ac</strong>ity was mainly in <strong>th</strong>e form<br />
<strong>of</strong> small units and <strong>th</strong>e average size remained at 12,500 t/year. From 1980-1985, an increase in <strong>th</strong>e<br />
number <strong>of</strong> units by more <strong>th</strong>an 100% was realized, wi<strong>th</strong> small paper mills registering a grow<strong>th</strong> <strong>of</strong><br />
129% and cap<strong>ac</strong>ity increase <strong>of</strong> 50%. However, only one large integrated mill (<strong>th</strong>e Nagaland Pulp<br />
and Paper Mill wi<strong>th</strong> a cap<strong>ac</strong>ity <strong>of</strong> 33,000 t/year) was commissioned during <strong>th</strong>e period, while four<br />
o<strong>th</strong>er large mills effected expansion for a total <strong>of</strong> 44,500 tons. A small pulp mill (<strong>th</strong>e Century Pulp<br />
and Paper Mill wi<strong>th</strong> a cap<strong>ac</strong>ity <strong>of</strong> 20,000 t/year) was commissioned in 1981 and <strong>th</strong>e average unit<br />
size came down to about 9,400 t/year.<br />
Ton / Year<br />
4000<br />
3500<br />
3000<br />
2500<br />
2000<br />
1500<br />
1000<br />
500<br />
0<br />
1960 1970 1980 1990 1992<br />
Installed Cap<strong>ac</strong>ity<br />
Production<br />
Figure 6.2.1 Installed cap<strong>ac</strong>ity and production <strong>of</strong> India’s pulp & paper industry<br />
Figure 6.2.2 Per capita paper consumption in India<br />
In 1988, only one large integrated pulp and paper mill (<strong>th</strong>e C<strong>ac</strong>har Paper Project <strong>of</strong> Hindustan<br />
Paper Corporation, wi<strong>th</strong> a cap<strong>ac</strong>ity <strong>of</strong> 100,000 tons) was commissioned. The rest <strong>of</strong> <strong>th</strong>e additions<br />
to <strong>th</strong>e existing cap<strong>ac</strong>ity was by way <strong>of</strong> expanding a few small paper mills. After <strong>th</strong>e commissioning<br />
<strong>of</strong> <strong>th</strong>e C<strong>ac</strong>har project, <strong>th</strong>ere has been no fur<strong>th</strong>er commissioning <strong>of</strong> integrated pulp and paper mills<br />
based on forest raw materials.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 81<br />
The number <strong>of</strong> large mills went up to 25 in 1990, and in 1992, <strong>th</strong>ree large mills (Pudumjee Pulp<br />
and Paper Mill, Balkrishna Papers, and Tribeni Tissues, Ltd.) were added as a result <strong>of</strong> expansion<br />
from <strong>th</strong>e small category. Similarly in 1993, two large mills have been added <strong>th</strong>rough expansion and<br />
two new agro-residues-based units have been set up. During <strong>th</strong>e last five years, only <strong>th</strong>ree new<br />
units were set up in <strong>th</strong>e large paper mill category. The trend <strong>of</strong> setting up small paper mills<br />
<strong>ac</strong>counting for about 50% <strong>of</strong> <strong>th</strong>e total cap<strong>ac</strong>ity is continuing. The average unit has also remained at<br />
about 10,000 tons. The grow<strong>th</strong> <strong>of</strong> <strong>th</strong>e paper industry in India is shown in Figure 6.2.3.<br />
# <strong>of</strong> mills<br />
300<br />
250<br />
200<br />
150<br />
100<br />
50<br />
0<br />
Small Paper Mills<br />
Integrated Paper Mills<br />
1960 1970 1980<br />
Year<br />
1990 1992<br />
Figure 6.2.3 Grow<strong>th</strong> <strong>of</strong> <strong>th</strong>e paper industry in India (1960 to 1992)<br />
6.2.2.2 Raw materials scenario<br />
Twenty years ago, <strong>th</strong>e Indian paper industry started wi<strong>th</strong> bamboo as <strong>th</strong>e sole major raw material.<br />
The restricted availability <strong>of</strong> <strong>th</strong>e material, however, has curtailed its usage to about 40% at present.<br />
Because <strong>of</strong> <strong>th</strong>is, <strong>th</strong>ere has been a considerable shift towards <strong>th</strong>e use <strong>of</strong> tropical hardwood,<br />
eucalyptus, and o<strong>th</strong>er non-conventional raw materials.<br />
Today, depending on <strong>th</strong>e source <strong>of</strong> raw material, <strong>th</strong>e paper industry is classified as follows:<br />
- Forest-based: bamboo & hardwood (plantation-grown raw materials: mainly Eucalyptus<br />
and Subabul)<br />
- Unconventional raw materials (agro-residues, jute, grass straw, bagasse, etc.)<br />
- Waste paper-based<br />
Segment wise, effective installed cap<strong>ac</strong>ities in <strong>th</strong>e paper industry are as follows:<br />
Forest-based raw material: 43%<br />
Agro-based 28%<br />
Waste paper-based 29%
82 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Today, <strong>th</strong>e large gap between <strong>th</strong>e demand and supply for paper is basically for <strong>th</strong>e newsprint type<br />
while future requirements for paper and paper board are expected to register a sharp increase.<br />
There is <strong>th</strong>erefore a need to substitute scarce forest resources wi<strong>th</strong> non-conventional raw materials<br />
as an immediate measure to meet raw material requirements in <strong>th</strong>e pulp & paper industry.<br />
Plantations on long-term basis by using modern silviculture pr<strong>ac</strong>tices and o<strong>th</strong>er technologies like<br />
tissue culture for improving <strong>th</strong>e productivity <strong>of</strong> <strong>th</strong>e forest-based raw materials should be<br />
considered.<br />
6.2.2.3 Technological advancement<br />
Since its establishment, <strong>th</strong>e paper industry in India underwent a lot <strong>of</strong> changes by way <strong>of</strong><br />
equipment and process development. A hundred years ago, <strong>th</strong>e m<strong>ac</strong>hinery and equipment available<br />
for pulping, ble<strong>ac</strong>hing and papermaking, limited <strong>th</strong>e size <strong>of</strong> <strong>th</strong>e mills to about 50 t/d. Apart from<br />
constraints such as <strong>th</strong>e availability <strong>of</strong> energy, raw materials and o<strong>th</strong>er inputs, one reason for <strong>th</strong>e low<br />
cap<strong>ac</strong>ity utilization <strong>of</strong> <strong>th</strong>e mills is <strong>th</strong>e f<strong>ac</strong>t <strong>th</strong>at productive assets are <strong>of</strong>ten not at optimum levels <strong>of</strong><br />
efficiency due to <strong>th</strong>e l<strong>ac</strong>k <strong>of</strong> modernization and renovation <strong>of</strong> old equipment. Fur<strong>th</strong>ermore, <strong>th</strong>e<br />
Indian paper industry has adopted equipment primarily designed for <strong>th</strong>e processing <strong>of</strong> indigenous<br />
s<strong>of</strong>twood materials, such as bamboo, but <strong>th</strong>ese are used for hardwood as well. Consequently,<br />
operating efficiencies are low and processes require modernization <strong>of</strong> techniques to ensure better<br />
yields, reduce costs and conserve raw materials.<br />
In view <strong>of</strong> <strong>th</strong>e increasing paper demand and shortage <strong>of</strong> forest-based raw materials, <strong>th</strong>e<br />
government has drawn up a policy to promote small mills based on straw and bagasse. The size <strong>of</strong><br />
<strong>th</strong>e mill has to be restricted due to <strong>th</strong>e seasonal availability <strong>of</strong> <strong>th</strong>e raw materials, and technical<br />
problems involved. These agro-based paper mills produce almost all kinds <strong>of</strong> paper and boards for<br />
writing and printing. In <strong>th</strong>e absence <strong>of</strong> a chemical recovery system and high cost <strong>of</strong> alkali, <strong>th</strong>ese<br />
mills use low amounts <strong>of</strong> chemicals at <strong>th</strong>e cooking stage and excess amounts <strong>of</strong> chlorine in <strong>th</strong>e<br />
ble<strong>ac</strong>hing stage. Second-hand paper m<strong>ac</strong>hines which are used for papermaking are energy<br />
deficient, and since <strong>th</strong>ese mills do not have chemical recovery units, <strong>th</strong>e discharge <strong>of</strong> spent liquor,<br />
and excess consumption <strong>of</strong> chlorine are major causes <strong>of</strong> water and environmental pollution.<br />
On <strong>th</strong>e o<strong>th</strong>er hand, <strong>th</strong>e large integrated mills which mainly produce writing and printing grade<br />
papers are equipped wi<strong>th</strong> full-fledged chemical recovery systems and effluent treatment plants.<br />
Developments in <strong>th</strong>e pulp and paper industry has been gradual, <strong>th</strong>ough systematic and elaborate<br />
research <strong>ac</strong>tivities in <strong>th</strong>e fields <strong>of</strong> fiber chemistry, morphology, engineering, have been continuing.<br />
Today, advanced knowledge in morphology and structure <strong>of</strong> fibers, chemical re<strong>ac</strong>tions <strong>of</strong> wood<br />
components such as carbohydrates and lignin during pulping and ble<strong>ac</strong>hing, has led to several<br />
technological innovations in <strong>th</strong>e field <strong>of</strong> pulping. The spectrum <strong>of</strong> fibrous raw materials which was<br />
initially limited to wood, has widened to non-wood fibrous raw materials.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 83<br />
The papermaking process involves <strong>th</strong>ree main stages: raw material preparation, pulping and<br />
ble<strong>ac</strong>hing, and papermaking.<br />
A. Raw material preparation<br />
Wood and bamboo are felled at <strong>th</strong>e forests. Wood is debarked at <strong>th</strong>e felling or mill site. The fiber<br />
losses in handling is more <strong>th</strong>an 10%. Agricultural residues like straws & bagasse are stored in<br />
bales. Being seasonal crops, <strong>th</strong>eir storage for long periods are prone to microbial degradation<br />
which <strong>of</strong>ten affects <strong>th</strong>e quality <strong>of</strong> pulp produced.<br />
Chipping<br />
The wood is chipped in disc chippers which are also used for bamboo chipping, <strong>th</strong>ough <strong>th</strong>e<br />
Palman Drum type is nowadays commonly used for bamboo. About 53% <strong>of</strong> <strong>th</strong>e total number <strong>of</strong><br />
chippers (<strong>ac</strong>counting for 58% <strong>of</strong> <strong>th</strong>e total installed cap<strong>ac</strong>ity) were installed since 1975, and are<br />
mostly <strong>of</strong> <strong>th</strong>e drum types. While <strong>th</strong>e aggregate cap<strong>ac</strong>ity <strong>of</strong> chippers for individual units range<br />
between 35 to 168 t/h, most units fall between 45-50 t/h cap<strong>ac</strong>ity. Straws are cut by chop cutters,<br />
which are not power efficient, while bagasse is de-pi<strong>th</strong>ed before digestion.<br />
B. Pulping and ble<strong>ac</strong>hing<br />
Indian mills predominantly use <strong>th</strong>e alkaline pulping process. Large mills based on forest raw<br />
materials use <strong>th</strong>e Kraft process, whereas agro-based mills use <strong>th</strong>e soda process. Newsprint mills<br />
use mechanical, chemical, chemi-mechanical and chemi-<strong>th</strong>ermomechanical (CTMP) processes.<br />
Digestion<br />
The predominant pr<strong>ac</strong>tice for digestion is <strong>th</strong>e use <strong>of</strong> batch digesters. Two large mills use<br />
continuous digesters for bamboo and wood, whereas some <strong>of</strong> <strong>th</strong>e agro-based mills use Pandya<br />
digesters. The reasons for not using continuous digesters in agro-based mills include:<br />
- higher outlays for m<strong>ac</strong>hinery repl<strong>ac</strong>ement in <strong>th</strong>e existing units<br />
- l<strong>ac</strong>k <strong>of</strong> flexibility in <strong>th</strong>e continuous digester process system to <strong>ac</strong>cept varying raw material<br />
mix<br />
- <strong>th</strong>e relatively small size <strong>of</strong> <strong>th</strong>e mills makes it uneconomical to use continuous digesters<br />
more efficiently<br />
Ble<strong>ac</strong>hing<br />
Most Indian mills use chlorine-based ble<strong>ac</strong>hing chemicals wi<strong>th</strong> barometer drop leg or displ<strong>ac</strong>ement<br />
type <strong>of</strong> washers. Common ble<strong>ac</strong>hing sequences are CEHH, CEH, and CHHH, <strong>of</strong> which CEHH is<br />
most commonly used in order to <strong>ac</strong>hieve a brightness level <strong>of</strong> over 75%. Some large mills have
84 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
started using chlorine dioxide and peroxide partially, i.e., CE (p)HH, while many paper mills propose<br />
to go for oxygen ble<strong>ac</strong>hing.<br />
Pulp Washing<br />
Small mills wi<strong>th</strong>out chemical recovery systems normally employ <strong>th</strong>e po<strong>ac</strong>her-type washer followed<br />
by one or two drum washers. The fresh water consumption is as high as 20-50 m 3 /t (paper) in<br />
<strong>th</strong>ese mills. Integrated mills have 3-4 drum washers wi<strong>th</strong> counter-current washing.<br />
Stock Preparation<br />
Most <strong>of</strong> <strong>th</strong>e units have repl<strong>ac</strong>ed conical and wide angle refiners wi<strong>th</strong> <strong>th</strong>e relatively energy efficient<br />
double disc refiners.<br />
C. Paper m<strong>ac</strong>hines<br />
Three types <strong>of</strong> paper m<strong>ac</strong>hines are commonly employed in <strong>th</strong>e industry: cylinder molds,<br />
Fourdrinier formers, and twin wire formers<br />
The cylinder molds are commonly used for small mills engaged in <strong>th</strong>e manuf<strong>ac</strong>ture <strong>of</strong> multi-layered<br />
boards. The Fourdrinier m<strong>ac</strong>hines are most commonly employed bo<strong>th</strong> in small and big mills for<br />
<strong>th</strong>e manuf<strong>ac</strong>ture <strong>of</strong> varieties <strong>of</strong> paper. About 81% <strong>of</strong> <strong>th</strong>e total paper m<strong>ac</strong>hines have Fourdrinier<br />
formers and 84% have speeds <strong>of</strong> 150 to 300 meters per minute (mpm). Only 5 m<strong>ac</strong>hines have<br />
operating speeds <strong>of</strong> more <strong>th</strong>an 400 mpm.<br />
Twinformers <strong>th</strong>at are commonly employed in <strong>th</strong>e newsprint industry, have high speeds and can<br />
<strong>ac</strong>cept weaker pulp. However, <strong>th</strong>eir application in small units is not economically viable.<br />
O<strong>th</strong>er data regarding paper m<strong>ac</strong>hines used in <strong>th</strong>e industry are as follows: 56% <strong>of</strong> <strong>th</strong>e total number<br />
<strong>of</strong> paper m<strong>ac</strong>hines have <strong>th</strong>yrister control drives; 30% have sectorial drives, and 33% have<br />
line/pulley drives; 48% have open type <strong>of</strong> head boxes; 52% have closed-type head boxes; 62%<br />
have suction processes; 39% are equipped wi<strong>th</strong> size presses while 69% are equipped wi<strong>th</strong><br />
calendars. The condensate recovery in most <strong>of</strong> <strong>th</strong>e mills is between 60% to 90%.<br />
D. Chemical recovery system<br />
While all wood-based paper mills have chemical recovery systems, most <strong>of</strong> <strong>th</strong>e small mills do not<br />
have one, and <strong>th</strong>e efficiency attained in <strong>th</strong>e recovery units are below 90%. Impressive<br />
developments, however, have been made in <strong>th</strong>e evaporation and combustion <strong>of</strong> spent liquor.<br />
From <strong>th</strong>e 60s to <strong>th</strong>e 80s mills have installed ei<strong>th</strong>er short-tube or long-tube variety types <strong>of</strong><br />
evaporators. Since spent liquor exhibit very high viscosity, <strong>th</strong>is restricts <strong>th</strong>e evaporator outlet<br />
concentration to 40-45% solids. Scaling tendencies and colloidal instability <strong>of</strong> spent liquor are also<br />
<strong>th</strong>e common problems f<strong>ac</strong>ed in evaporator units. Recently, <strong>th</strong>e use <strong>of</strong> <strong>th</strong>e falling-film type <strong>of</strong>
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 85<br />
evaporator has been favored. Experience wi<strong>th</strong> <strong>th</strong>ese evaporators have shown clean benefits like<br />
high-end concentration, maximum steam economy and improved condensate quality.<br />
Boilers used in <strong>th</strong>e industry are <strong>th</strong>e coal-fired types. About 11% <strong>of</strong> <strong>th</strong>e total installed cap<strong>ac</strong>ity,<br />
mainly fluidized bed boilers, are 5 years <strong>of</strong> age. Prior to 1975, <strong>th</strong>e cap<strong>ac</strong>ity was 20 t/h <strong>of</strong> steam<br />
generated at 20-30 kg/cm 2 pressure and 380 o C to 400 o C temperature, wi<strong>th</strong> a <strong>th</strong>ermal efficiency <strong>of</strong><br />
50-60%. From 1975 onwards, <strong>th</strong>e steam generation cap<strong>ac</strong>ity increased to 25-27 t/h at 40-60<br />
kg/cm 2 pressure and 400 o C to 480 o C temperature. Thermal efficiency has increased to 70-80%.<br />
The Central Pulp and Paper Research <strong>Institute</strong> (CPPRI) is engaged in developing <strong>th</strong>e Direct Alkali<br />
Recovery System (DARS) for agro-based mills. Organizations like ESVIN Technologies and Amrit<br />
Banaspati Company are also engaged in R&D work for chemical recovery. CPPRI has made<br />
break<strong>th</strong>roughs in <strong>th</strong>e desilication <strong>of</strong> bl<strong>ac</strong>k liquor <strong>th</strong>at will improve performance <strong>of</strong> <strong>th</strong>e recovery<br />
unit in non-wood-based paper mills, while opening <strong>th</strong>e option for lime sludge reburning.<br />
E. O<strong>th</strong>er m<strong>ac</strong>hinery and equipment<br />
The manuf<strong>ac</strong>ture <strong>of</strong> paper from raw materials storage & transport to <strong>th</strong>e p<strong>ac</strong>king and handling <strong>of</strong><br />
<strong>th</strong>e finished product requires utilization <strong>of</strong> a wide range <strong>of</strong> equipment. In addition, various auxiliary<br />
items such as steam boilers, power generation equipment, effluent treatment equipment, etc., are<br />
also required.<br />
India has now developed its capability to manuf<strong>ac</strong>ture and supply almost <strong>th</strong>e entire range <strong>of</strong><br />
equipment for <strong>th</strong>e paper industry, specifically for <strong>th</strong>e pulping plant and stock preparation;<br />
equipment such as paper m<strong>ac</strong>hines, steam and power generation equipment, chemical recovery<br />
equipment, etc. Figure 6.2.4 shows <strong>th</strong>e general distribution <strong>of</strong> process automation in <strong>th</strong>e paper<br />
industry <strong>of</strong> India.<br />
6.2.2.4 Human resource in <strong>th</strong>e Indian paper industry<br />
Despite <strong>th</strong>e grow<strong>th</strong> <strong>of</strong> <strong>th</strong>e paper industry, industrial performance has been unsatisf<strong>ac</strong>tory due to<br />
<strong>th</strong>e poor management <strong>of</strong> materials, money, and manpower, <strong>of</strong> which manpower planning and<br />
training is most neglected. For a sustained performance, <strong>th</strong>e industry should have <strong>th</strong>e ability to<br />
adopt appropriate technology to conserve energy and raw materials, and to cut down costs. This<br />
challenge can be f<strong>ac</strong>ed only <strong>th</strong>rough a competent and skilled manpower at all levels. On <strong>th</strong>e<br />
average, <strong>th</strong>e industry utilizes 78 persons in <strong>th</strong>e production line per 1,000 annual tons <strong>of</strong><br />
production. The technical manpower components are 35-40 and 40-60 for every 1,000 annual<br />
tons in <strong>th</strong>e large and small mills, respectively. For <strong>th</strong>e whole Indian paper industry, pr<strong>of</strong>essional<br />
and technical manpower comprise 13% <strong>of</strong> <strong>th</strong>e total manpower; administrative/executive and<br />
managerial personnel constitute 23%; 12% are clerical personnel, 7% are service workers, and 45%<br />
are production-related workers.
86 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
To meet <strong>th</strong>e challenges <strong>of</strong> technical upgrading and productivity improvement, <strong>th</strong>e industry will<br />
strive for a reduction in its manpower usage wi<strong>th</strong> an associated rise in workers’ competence. For<br />
<strong>th</strong>e next 10-12 years, it is estimated <strong>th</strong>at <strong>th</strong>e average manpower utilization in <strong>th</strong>e country will be 35<br />
persons per 1,000 annual tons in <strong>th</strong>e paper & paper board sector, and 15-20 persons per 1,000<br />
annual tons in <strong>th</strong>e newsprint sector. Training programs in <strong>th</strong>e pulp and paper industry will be<br />
modified to fit into <strong>th</strong>e national pattern for degree/polytechnic diploma levels. The entire strategy<br />
<strong>of</strong> manpower development will involve training competent/skilled personnel to move <strong>th</strong>e industry<br />
to perform at its best level.<br />
Status (% <strong>of</strong> F<strong>ac</strong>tories)<br />
70<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
1985 1990 1991 1992 1993<br />
Computerization Electronic Automation<br />
Electro Mechanical Regulation Manual Operation<br />
Figure 6.2.4. Status <strong>of</strong> process automation in <strong>th</strong>e paper industry<br />
6.2.2.5 Current status <strong>of</strong> <strong>th</strong>e pulp and paper industry in Indian national economy<br />
The paper industry constitutes <strong>th</strong>e core <strong>of</strong> industries directly linked to <strong>th</strong>e national economy.<br />
Current per capita consumption <strong>of</strong> paper is 2.5 kg, and is expected to grow to 4.2 kg by <strong>th</strong>e end <strong>of</strong><br />
<strong>th</strong>e century. Efforts to build additional cap<strong>ac</strong>ity to meet <strong>th</strong>e future requirements <strong>of</strong> various grades<br />
<strong>of</strong> paper are on-going. In f<strong>ac</strong>t, <strong>th</strong>e country has attained self-sufficiency in most varieties <strong>of</strong><br />
industrial paper. Newsprint, <strong>th</strong>ough, is still imported at 40% levels, implying a considerable<br />
outflow <strong>of</strong> foreign exchange.<br />
Considering <strong>th</strong>e huge amount <strong>of</strong> non-conventional raw materials available for pulp and paper<br />
manuf<strong>ac</strong>ture, <strong>th</strong>ere exists a big export potential in <strong>th</strong>e pulp and paper sector. In 1994-1995 alone,<br />
nearly 200,000 tons <strong>of</strong> paper had been exported to <strong>th</strong>ird world countries.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 87<br />
6.2.3 Evolution <strong>of</strong> energy efficiency in Indian pulp and paper industry<br />
Pulp and paper being an energy intensive industry, is ranked <strong>th</strong>e six<strong>th</strong> largest energy consumer in<br />
<strong>th</strong>e country. Fuels from external sources comprise 70% <strong>of</strong> <strong>th</strong>e total used, as compared to 30-40%<br />
for <strong>th</strong>ose in developed countries. The energy component in <strong>th</strong>e Indian paper industry is as high as<br />
30% <strong>of</strong> <strong>th</strong>e total cost <strong>of</strong> production, consuming about 7% <strong>of</strong> <strong>th</strong>e country’s coal and approximately<br />
3% <strong>of</strong> <strong>th</strong>e electrical energy requirements <strong>of</strong> <strong>th</strong>e whole manuf<strong>ac</strong>turing sector. Unlike o<strong>th</strong>er<br />
industries, <strong>th</strong>e paper industry requires large quantity <strong>of</strong> low grade energy (200 o C). Of <strong>th</strong>e total<br />
energy requirements, about 15-25% is <strong>of</strong> high grade (electrical energy), and <strong>th</strong>e rest is constituted<br />
by low grade energy. In terms <strong>of</strong> <strong>th</strong>ermodynamic efficiency, <strong>th</strong>e industry is lowest among <strong>th</strong>e<br />
energy intensive manuf<strong>ac</strong>turing units <strong>of</strong> <strong>th</strong>e steel and cement industries.<br />
The industry was greatly affected by <strong>th</strong>e energy crisis in <strong>th</strong>e early 1970s, which led to <strong>th</strong>e adoption<br />
<strong>of</strong> energy conservation me<strong>th</strong>ods. Most <strong>of</strong> <strong>th</strong>e mills installed before <strong>th</strong>e 1970 crisis however, were<br />
not energy conserving in design and technology. Even <strong>th</strong>ough <strong>th</strong>e concept <strong>of</strong> energy savings<br />
intensity had already been identified in <strong>th</strong>e 80s, consumption patterns remained <strong>th</strong>e same, brought<br />
about by <strong>th</strong>e following:<br />
- l<strong>ac</strong>k <strong>of</strong> modernization<br />
- use <strong>of</strong> obsolete technology<br />
- l<strong>ac</strong>k <strong>of</strong> process control system<br />
- change in fibrous raw material mix<br />
The estimated energy consumption in <strong>th</strong>e pulp and paper industry is 2.42 tons <strong>of</strong> oil equivalent per<br />
ton <strong>of</strong> paper. The major energy-consuming plants are <strong>th</strong>e chippers, digesters, refiners, paper<br />
m<strong>ac</strong>hines and evaporation plants. The present specific energy consumption patterns show higher<br />
variations in <strong>th</strong>e integrated pulp and paper mills. The specific steam consumption varies from 10.2<br />
to 17.4 tons/ton <strong>of</strong> paper produced, while <strong>th</strong>e specific power consumption varies from 1,300 to<br />
1,940 kWh/ton <strong>of</strong> paper. Water consumption also varies from 225 m 3 to 450 m 3 /ton <strong>of</strong> paper.<br />
In <strong>th</strong>e last decade, <strong>th</strong>e cost <strong>of</strong> coal and electricity has increased by 500% and fuel oil by 1000%.<br />
Based on <strong>th</strong>e industry’s 4.25 million tons <strong>of</strong> total installed cap<strong>ac</strong>ity and cap<strong>ac</strong>ity utilization for all<br />
products, <strong>th</strong>e projected consumption <strong>of</strong> <strong>th</strong>e paper industry by year 2000 would require an<br />
additional 3.0 million tons <strong>of</strong> coal and about 1.82 million kWh electricity. This means a 76%<br />
increase in coal requirements and 139% increase in electricity requirements. Wi<strong>th</strong> rising energy<br />
costs, ways and means to conserve energy now becomes a major <strong>th</strong>rust in <strong>th</strong>e industry.<br />
Energy consumption patterns in developed countries and in India<br />
Between 1975-1983, <strong>th</strong>e Japanese paper industry has reduced its specific energy consumption from<br />
0.662 toe to 0.437 toe per ton <strong>of</strong> paper, <strong>ac</strong>counting for a 34% reduction in specific energy
88 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
consumption. This could be attributed to <strong>th</strong>e country’s heavy investments in fossil fuel substitution<br />
energy programs. European oil consumption has also been cut down from 37% to 8%. The<br />
Swedish paper industry managed to cut its oil fuel consumption by over 70% between 1973 and<br />
1983. In <strong>th</strong>e USA, energy from residual fuel and self-generating sources now <strong>ac</strong>counts for an<br />
estimated 57-58 percent.<br />
Clearly, most <strong>of</strong> <strong>th</strong>e developed countries have made significant progress to conserve energy, and<br />
are presently depending only on 30-40% <strong>of</strong> fuels from external sources. India however, is still 70%<br />
dependent on external fuels. The industry’s specific energy consumption varies between 0.76 to<br />
1.325 toe per ton <strong>of</strong> paper.<br />
Table 6.2.1, Table 6.2.2 and Figure 6.2.5 show a comparison between mills in India and <strong>th</strong>e<br />
developed countries, and energy consumption patterns in <strong>th</strong>e country. It is wor<strong>th</strong>while to note<br />
<strong>th</strong>at some Indian paper mills have already taken some in-plant energy conservation measures.<br />
Table 6.2.1 Comparison <strong>of</strong> energy consumption <strong>of</strong> developed countries and India<br />
Particulars Developed countries India<br />
Total specific steam consumption, t/t paper 6.5-8.5 10-16<br />
Digester 1.9-2.3 2.3-3.9<br />
Evaporator 1.5-2.2 2.5-4.0<br />
Paper m<strong>ac</strong>hine 1.9-2.0 3.0-4.0<br />
S/R plant 0.3-0.5 0.5-1.1<br />
Ble<strong>ac</strong>h plant 0.2-0.25 0.35-0.40<br />
Steam generator per ton <strong>of</strong> bl<strong>ac</strong>k solids 3.0-3.5 1.5-2.5<br />
Table 6.2.2 Electricity consumption <strong>of</strong> paper in Developing countries and India (kWh/t)<br />
Particulars Developed countries India<br />
Total Consumption 1150-1250 1200-1700<br />
Chipper 92-98 112-128<br />
Digester 43-46 58-62<br />
Washing and screening 116-122 145-155<br />
Ble<strong>ac</strong>hing plant 66-69 88-92<br />
Stock preparation 164-175 275-286<br />
Paper m<strong>ac</strong>hine 410-415 465-475<br />
S/R plant 127-135 170-190<br />
Utilities & o<strong>th</strong>ers 160-165 246-252<br />
Total specific energy (Gcal/t) 4.14-4.50 4.32-6.12
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 89<br />
2.5<br />
2.0<br />
1.5<br />
1.0<br />
0.5<br />
0<br />
1960 1970 1980 1990 1992<br />
Specific electricity, MWh / ton Paper<br />
Specific coal, toe / ton Paper<br />
Specific fuel oil, toe / ton Paper<br />
Specific non-conventional energy, toe / ton Paper<br />
Integrated specific energy, toe / ton Paper<br />
Figure 6.2.5 Energy consumption pattern in <strong>th</strong>e Indian paper industry<br />
6.2.4 Environmental externalities <strong>of</strong> technological development in <strong>th</strong>e pulp and paper<br />
industry<br />
The pulp and paper industry is essentially a chemical process industry wi<strong>th</strong> a distinctive imp<strong>ac</strong>t on<br />
<strong>th</strong>e environment. It is estimated <strong>th</strong>at about 41.8% <strong>of</strong> wood is recovered as ble<strong>ac</strong>hed pulp, roughly<br />
4.2% <strong>of</strong> <strong>th</strong>e remaining wood ends up as solid waste, as 5.25% goes into waste waters as dissolved<br />
organic matter, and 2.3% ends up as suspended solids also in wastewater.<br />
The potential pollutants from a pulp and paper mill fall into four categories as follows:<br />
- effluents<br />
- air pollutants<br />
- solid wastes<br />
- noise pollution
90 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
6.2.4.1 Effluents<br />
Waste water is discharged from almost all unit operations. Large paper mill waste waters are<br />
generally segregated into streams, namely, colored streams (due to lignin from pulp washing,<br />
caustic extr<strong>ac</strong>tion and chemical recovery sector), and colorless stream (chipper house, chlorination,<br />
hypochlorite and paper m<strong>ac</strong>hines). Ble<strong>ac</strong>h plant effluents constitute nearly 65% <strong>of</strong> <strong>th</strong>e total BOD<br />
and 90% <strong>of</strong> <strong>th</strong>e total color load <strong>of</strong> combined effluents in large mills.<br />
Small mills generate ostensibly higher pollution <strong>th</strong>an larger mills mainly due to <strong>th</strong>e absence <strong>of</strong><br />
chemical recovery systems. Major pollution loads come from spent pulping liquor, <strong>of</strong> which 90%<br />
<strong>of</strong> <strong>th</strong>e color and 50% <strong>of</strong> <strong>th</strong>e COD is due to lignin which is almost completely bio-refr<strong>ac</strong>tory.<br />
Tables 6.2.3 and 6.2.4 show <strong>th</strong>e effluent char<strong>ac</strong>teristics and <strong>th</strong>e pollution loads <strong>of</strong> bl<strong>ac</strong>k liquor and<br />
organics in Indian pulp and paper mills.<br />
Table 6.2.3 Char<strong>ac</strong>teristics <strong>of</strong> effluents from <strong>th</strong>e pulp and paper mills<br />
Integrated pulp Newsprint Agro-based small Waste paper<br />
& paper mills mills paper mills mills<br />
Raw material bamboo, hardwood bamboo, rice straw, wheat waste paper<br />
hardwood straw, bagasse, etc.<br />
waste water, m3/ton 230-250 200 200-380 70-150<br />
PH<br />
Pollution load, kg/ton paper:<br />
6.0-9.0 7.2-7.3 6.0-8.5 6.0-8.5<br />
Suspended solids 100-150 100 90-240 50-80<br />
BOD5 35-50 45 85-270 10-40<br />
COD 150-200 135 500-1100 50-90<br />
Table 6.2.4 Pollution loads <strong>of</strong> bl<strong>ac</strong>k liquor and organics<br />
Parameters Bagasse Rice straw<br />
COD, kg/t pulp 1075 1247<br />
BOD, kg/t pulp 216 234<br />
Bl<strong>ac</strong>k liquor COD/BOD<br />
5.0<br />
5.3<br />
Color, kg/t pulp (PCU)<br />
1394<br />
1514<br />
Acid precipitation COD, kg/t pulp 530 628<br />
Lignin separated BOD, kg/t pulp was not biodegradable was not biodegradable<br />
Color, kg/t pulp (PCU)<br />
1283<br />
1444<br />
Supernatant free<br />
from lignin<br />
COD, kg/t pulp<br />
BOD, kg/t pulp<br />
COD/BOD<br />
Color, kg/t pulp (PCU)<br />
417<br />
197<br />
2.1<br />
82<br />
381<br />
247<br />
1.5<br />
1113
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 91<br />
Al<strong>th</strong>ough <strong>th</strong>e spent pulping liquor is <strong>th</strong>e major source <strong>of</strong> pollution in terms <strong>of</strong> depleting oxygen<br />
conditions, <strong>th</strong>e toxicity <strong>of</strong> <strong>th</strong>e effluents in terms <strong>of</strong> Total Organic Chlorine (TOCl) originates from<br />
<strong>th</strong>e ble<strong>ac</strong>hing plant <strong>of</strong> <strong>th</strong>e large and small mills. The amount <strong>of</strong> TOCl produced is dependent on<br />
<strong>th</strong>e amount <strong>of</strong> free Cl2 used during ble<strong>ac</strong>hing operations and is roughly calculated by <strong>th</strong>e following<br />
equation:<br />
TOCl = K(C+D/5 +H/2) kg TOCl/air dried ton <strong>of</strong> pulp,<br />
where C, D, & H are doses <strong>of</strong> Cl 2, ClO 2 and hypochlorite.<br />
In India, <strong>th</strong>e situation due to <strong>th</strong>ese chloro compounds becomes more alarming in <strong>th</strong>e small paper<br />
mills. Increasing caustic soda prices and increasing gap between caustic soda and chlorine prices<br />
indicate a tendency to decrease alkali charge in cooking, <strong>th</strong>ereby increasing lignin content and<br />
chlorine consumption.<br />
6.2.4.2 Solid wastes<br />
Solid wastes constitute a complex problem in <strong>th</strong>e industry due to <strong>th</strong>e varying nature and enormity<br />
<strong>of</strong> <strong>th</strong>e wastes generated. Table 6.2.5 shows <strong>th</strong>e solid waste generation from <strong>th</strong>e small and large<br />
paper mills. The main sources <strong>of</strong> solid wastes are:<br />
- The raw material handling/preparation<br />
- The effluent sludge from <strong>th</strong>e combined mills effluent treatment plant<br />
- Flue dust from coal-fired boilers and fines in <strong>th</strong>e coal<br />
- Coal cinders from coal-fired boilers<br />
- Lime sludge from <strong>th</strong>e chemical recovery plant<br />
- Hypo mud from <strong>th</strong>e hypo plant<br />
- Pi<strong>th</strong> generation from <strong>th</strong>e de-pi<strong>th</strong>ing plant.<br />
Wastes from raw materials handling are burnt, discharged as effluent, or dumped in barren lands.<br />
Burning <strong>of</strong> lime sludge from causticizers and hypochlorite preparation plants in India, however, is<br />
unsuccessful due to <strong>th</strong>e high silica content. Hence, <strong>th</strong>e desilication <strong>of</strong> <strong>th</strong>e bl<strong>ac</strong>k liquor is essential.<br />
Moreover, sludge from water treatment or effluent treatment plants contains nearly 72% organic<br />
compounds and has 45-50% water content. Therefore, dewatering <strong>of</strong> <strong>th</strong>e sludge, and stabilizing <strong>th</strong>e<br />
water is necessary before its final disposal.<br />
Coal ash which <strong>ac</strong>counts for 30-32% <strong>of</strong> <strong>th</strong>e total coal burnt also adds to <strong>th</strong>e solid waste disposal<br />
problem. Most <strong>of</strong> it is used as landfill, al<strong>th</strong>ough its disposal is still a cause for concern.<br />
From <strong>th</strong>e foregoing discussion, <strong>th</strong>e seriousness <strong>of</strong> <strong>th</strong>e problems due to wastes generated from <strong>th</strong>e<br />
pulp and paper industry is not some<strong>th</strong>ing to be taken for granted. The pressure on land is already<br />
high, and unless long term plans are made to ei<strong>th</strong>er reburn <strong>th</strong>e lime sludge, to separate and re-use<br />
fibrous wastes, and to use coal ash for building materials, <strong>th</strong>e mills will f<strong>ac</strong>e serious problems for
92 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
solid waste disposal in <strong>th</strong>e coming years. The rising consciousness for a clean, heal<strong>th</strong>y environment<br />
and <strong>th</strong>e implementation <strong>of</strong> stringent measures for solid waste disposal will force <strong>th</strong>e industry to<br />
make decisions in order to stop environmental degradation.<br />
Table 6.2.5 Solid waste generation in paper mills<br />
Waste source Large paper mills<br />
(kg dry solids / ton<br />
paper)<br />
Raw material<br />
handling/preparation<br />
Small paper mills<br />
(kg dry solids / ton<br />
paper)<br />
45 210*<br />
Hypochlorite preparation grit 20 nil<br />
Recausticizing lime mud 593 nil<br />
Power plant/boiler ash** 656 1300<br />
Waste treatment plant***<br />
1. Primary sludge 159 105<br />
2. Secondary sludge 34 105<br />
TOTAL 1507 1731<br />
% inorganic solids 84 75<br />
% organic solids 16 25<br />
6.2.4.3 Air pollution<br />
Particulate and gaseous pollutants from <strong>th</strong>e pulp and paper mills are discharged <strong>th</strong>rough <strong>th</strong>e<br />
following:<br />
- Digester relief<br />
- Brown stock washers<br />
- Washer-ble<strong>ac</strong>h liquor preparation plant<br />
- Multi-effect evaporators for bl<strong>ac</strong>k liquor<br />
- Direct cont<strong>ac</strong>t evaporators like cascades, cyclones, etc.<br />
- Chemical recovery furn<strong>ac</strong>e<br />
- Smelt dissolving and slaking tanks<br />
- Lime kilns<br />
- Boiler flue gases<br />
* When bagasse is used in pl<strong>ac</strong>e <strong>of</strong> straw in SPM, solid waste generated from raw materials handling will<br />
be 550 kg/ton paper and total solid wastes will be 2071 kg/t wi<strong>th</strong> 65% inorganic solids.<br />
** Ash generation depends on % ash in coal and <strong>th</strong>e amount <strong>of</strong> power/steam generation.<br />
*** Estimated (assuming 0.5 kg mixed liquor suspended solids produced / kg BOD removed in <strong>ac</strong>tivated<br />
sludge treatment plant.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 93<br />
Air pollutants are generally controlled by <strong>th</strong>e dust-collecting equipment. Chemical particulates<br />
emitted from recovery furn<strong>ac</strong>es, smelt dissolving tanks and lime kilns, mostly <strong>of</strong> sodium sulfate<br />
and sodium carbonate, are controlled to a considerable extent by <strong>th</strong>e use <strong>of</strong> venturi scrubbers,<br />
electrostatic precipitators, and o<strong>th</strong>er effective dust-collecting devices.<br />
Emitted gases which are a variable mixture <strong>of</strong> hydrogen sulfide, me<strong>th</strong>yl mercaptans, dime<strong>th</strong>yl<br />
sulfide and sulfur dioxide, originate mainly from <strong>th</strong>e sulfate pulping process. Table 6.2.6 shows <strong>th</strong>e<br />
main emissions <strong>of</strong> reduced sulfur compounds from <strong>th</strong>e sulfate pulping process.<br />
Table 6.2.6 Main emissions <strong>of</strong> sulfur compounds from <strong>th</strong>e sulfate pulping process<br />
Emission rate, kg/t90<br />
Emission source<br />
Batch digester<br />
H2S 0-0.15<br />
*MM<br />
CH3SH 0-1.3<br />
*DMS<br />
CH3SCH3 0.05-3.3<br />
*DMDS<br />
CH3SSC H3 0.05-2.0<br />
Continuous digester 0-0.10 0.5-1 0.05-0.5 0.05-0.4<br />
Washing 0-0.10 0.05-1 0.1-1.0 0.1-0.08<br />
Evaporation 0.05-1.5 0.05-0.8 0.05-1.0 0.05-1.0<br />
Recovery Furn<strong>ac</strong>e (wi<strong>th</strong><br />
DCE)<br />
0-2.50 0-2 0-1 0.03<br />
Smelt dissolving tank 0-1.0 0-0.08 0-0.5 0.03<br />
*MM: Me<strong>th</strong>yl-mercaptan; DMS: Dime<strong>th</strong>yl sulfide; DMDS: Dime<strong>th</strong>yl Disulfide<br />
6.2.4.4 Noise pollution<br />
The major contribution to noise pollution comes from <strong>th</strong>e chipper house, v<strong>ac</strong>uum pumps and<br />
compressors. Mufflers are necessary to reduce noise in v<strong>ac</strong>uum pumps; and in <strong>th</strong>e paper m<strong>ac</strong>hine<br />
drive, changing <strong>th</strong>e material <strong>of</strong> construction not only reduces noise, it also has <strong>th</strong>e additional<br />
advantage <strong>of</strong> self-lubrication. Wherever possible, <strong>th</strong>e paper m<strong>ac</strong>hine drive gears are made <strong>of</strong><br />
polypick or nylon material to serve <strong>th</strong>e purpose <strong>of</strong> reducing noise.<br />
6.2.5 Potential for energy efficiency improvement and pollution abatement <strong>th</strong>rough<br />
technological change<br />
6.2.5.1 Energy saving potential<br />
It is estimated <strong>th</strong>at <strong>th</strong>e energy bill <strong>of</strong> <strong>th</strong>e pulp and paper industry is about Rs 10 billion wi<strong>th</strong> a<br />
savings potential <strong>of</strong> at least 20% or Rs 2 billion, if a proper impetus is given to energy<br />
management. Technological renovations can play a significant role in improving <strong>th</strong>e energy<br />
efficiency <strong>of</strong> <strong>th</strong>e processes and lead to a reduction in specific energy consumption, improvement<br />
<strong>of</strong> energy and productivity and product quality. These may include major modifications <strong>of</strong> <strong>th</strong>e<br />
existing plants and changes in <strong>th</strong>e operating pr<strong>ac</strong>tices or process controls and equipment.
94 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
The industry can <strong>ac</strong>hieve better energy performance in a number <strong>of</strong> ways:<br />
- short-term schemes wi<strong>th</strong> small investments and improved housekeeping measures<br />
estimated to reduce <strong>th</strong>e energy bill by 5%<br />
- medium-term schemes wi<strong>th</strong> attr<strong>ac</strong>tive pay-b<strong>ac</strong>k periods can reduce <strong>th</strong>e energy bill by 10-<br />
15%<br />
- long-term schemes wi<strong>th</strong> major investments can cut <strong>th</strong>e energy bill by 5-10%.<br />
6.2.5.2 Energy and environmental audits, process modifications, optimization and control,<br />
and energy generation<br />
A. Energy and environmental audits<br />
Energy audit is used as a tool in defining and pursuing comprehensive energy management<br />
programs. Its primary objective is to determine ways <strong>of</strong> reducing energy consumption per unit <strong>of</strong><br />
product output. The process is conducted in two ways: preliminary audit and <strong>th</strong>e detailed audit.<br />
The preliminary audit is conducted in a limited span <strong>of</strong> time, focusing on <strong>th</strong>e major energy supply<br />
and demand aspects which <strong>ac</strong>count for 70% <strong>of</strong> <strong>th</strong>e total energy requirements. The detailed audit<br />
goes beyond <strong>th</strong>e quantitative estimates to cost savings.<br />
Environmental audits also help in identifying areas <strong>of</strong> high pollution loads which can be useful for<br />
<strong>th</strong>e management to come up wi<strong>th</strong> measures to reduce pollution discharges. In general, Indian<br />
paper mills adopt pollution abatement strategies <strong>of</strong> two types:<br />
- Internal measure: production process control aimed at reducing waste water volume and<br />
pollutant discharge load from <strong>th</strong>e mill<br />
- External measure: waste water treatment technologies or end-<strong>of</strong>-pipe treatment systems<br />
aimed at reducing discharges <strong>of</strong> pollutants to <strong>th</strong>e environment.<br />
B. Process modifications, optimization and advanced controls<br />
Through <strong>th</strong>e combination <strong>of</strong> modifying existing processes and <strong>th</strong>e development <strong>of</strong> new ones, <strong>th</strong>e<br />
objective <strong>of</strong> improving energy efficiency can be <strong>ac</strong>hieved. Considerable energy savings in <strong>th</strong>e<br />
industry has been reported brought about by such measures:<br />
- Digester: 10-20%<br />
- Ble<strong>ac</strong>hing 5-10%<br />
- Evaporator 3-5%<br />
- Recovery boiler 20-50%<br />
- Paper m<strong>ac</strong>hines 10-20%<br />
Following are some latest technologies <strong>th</strong>at are applied in <strong>th</strong>e pulp and paper industry <strong>of</strong> India:
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 95<br />
Raw Materials Handling<br />
1. Repl<strong>ac</strong>ement <strong>of</strong> disc chippers by drum chippers<br />
In some <strong>of</strong> <strong>th</strong>e mills, it has been observed <strong>th</strong>at <strong>th</strong>e repl<strong>ac</strong>ement <strong>of</strong> large numbers <strong>of</strong> disc-type low<br />
cap<strong>ac</strong>ity chippers wi<strong>th</strong> high cap<strong>ac</strong>ity chippers made it possible to reduce energy consumption from<br />
35 kWh to as low as 7 kWh/ TBD1 chips.<br />
Table 6.2.7 Comparative energy consumption <strong>of</strong> different chippers used<br />
Type <strong>of</strong> chippers Cap<strong>ac</strong>ity TBD Energy consumption<br />
kWh/ton <strong>of</strong> BD chip<br />
1. Drum type 20-25 7<br />
2. Disc type 6-10 30<br />
(Status: already in use in <strong>th</strong>ree large mills)<br />
2. Conversion <strong>of</strong> pneumatic conveyor to <strong>th</strong>e mechanical type<br />
80% <strong>of</strong> <strong>th</strong>e mills in India have resorted to <strong>th</strong>e mechanical type <strong>of</strong> conveying, and a reduction <strong>of</strong> 4-<br />
5 tons energy consumption had been realized. Performance-wise, <strong>th</strong>e cleated conveyor belts <strong>of</strong>fer<br />
an excellent alternative to <strong>th</strong>e pneumatic conveyors. Due to layout restrictions, however, <strong>th</strong>e o<strong>th</strong>er<br />
mills are not able to likewise do conversions.<br />
Pulping<br />
1. Installation <strong>of</strong> continuous digesters in pl<strong>ac</strong>e <strong>of</strong> batch digesters<br />
In some <strong>of</strong> <strong>th</strong>e large integrated mills mainly in <strong>th</strong>e public sector units, <strong>th</strong>e old conventional batch<br />
digesters are now being repl<strong>ac</strong>ed by continuous digesters, and are found to be energy efficient<br />
(Table 6.2.8). Advantages brought about by <strong>th</strong>e latter are:<br />
- uniform cooking and better pulp quality<br />
- low specific energy consumption<br />
- less alkali charge<br />
- shorter cooking cycle<br />
- higher liquor concentration for recovery<br />
2. RDH/Cold Blow System<br />
This technological innovation has been introduced for energy conservation <strong>of</strong> 20-25%, and are<br />
ideally suited for stationary digesters.<br />
1 TBD : Ton Bone Dry
96 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Table 6.2.8 Comparative performance <strong>of</strong> different digesters used<br />
Batch Continuous<br />
Steam/ton <strong>of</strong> pulp 1.6 1.0<br />
Power units/ton <strong>of</strong> pulp 150 56<br />
Alkali (%) 16 14<br />
(Status: HPC units (Nawgaon, C<strong>ac</strong>har) have Kamyr digesters whereas Seshashayee<br />
Paper Boards and Tamilnadu News Print Ltd. have Pandia continuous digesters.)<br />
Ble<strong>ac</strong>hing<br />
1. Oxygen ble<strong>ac</strong>hing<br />
This process is being used in paper mills which go for a low kappa number pulping. The<br />
introduction <strong>of</strong> oxygen delignification before ble<strong>ac</strong>hing reduces <strong>th</strong>e ble<strong>ac</strong>h consumption, making<br />
<strong>th</strong>e ble<strong>ac</strong>h effluent less toxic towards <strong>th</strong>e environment wi<strong>th</strong> <strong>th</strong>e added advantage <strong>of</strong> being able to<br />
generate additional steam from extr<strong>ac</strong>ted organics at <strong>th</strong>e oxygen stage.<br />
Ano<strong>th</strong>er recently introduced ble<strong>ac</strong>hing technique is <strong>th</strong>e use <strong>of</strong> peroxide in <strong>th</strong>e conventional<br />
systems, which has already been adopted in one <strong>of</strong> <strong>th</strong>e paper mills in <strong>th</strong>e country.<br />
2. Stock preparation<br />
Most <strong>of</strong> <strong>th</strong>e Indian integrated and non-integrated paper mills are repl<strong>ac</strong>ing <strong>th</strong>e conventional conical<br />
and wide angle refiners wi<strong>th</strong> disc refiners, which are found to be comparatively highly energy<br />
efficient (Table 6.2.9).<br />
Table 6.2.9 Comparative power consumption <strong>of</strong> different refiners used<br />
Type Specific energy consumption<br />
(kWh / sr / ton <strong>of</strong> pulp)<br />
Wide angle refiner 14-18<br />
Conical refiner 9-13<br />
Double disc refiner 7-9<br />
Triple disc refiner 6<br />
Chemical Recovery<br />
1. Evaporators<br />
The type <strong>of</strong> evaporators being used in <strong>th</strong>e Indian paper industry has been <strong>th</strong>e long & short tube<br />
evaporators. These are currently being repl<strong>ac</strong>ed by <strong>th</strong>e 7-effect free falling film type evaporators<br />
which reduce steam consumption by 25-30% in <strong>th</strong>e evaporator section. Increasing <strong>th</strong>e number <strong>of</strong><br />
effects <strong>of</strong> falling film evaporators can <strong>ac</strong>hieve a steam economy as high as 8.0.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 97<br />
Recently, high pressure pumps have also been installed in some <strong>of</strong> <strong>th</strong>e paper mills which help to<br />
improve steam economy from 4.2 to 4.8.<br />
2. Energy cogeneration <strong>th</strong>rough boiler modifications<br />
A number <strong>of</strong> improvements in <strong>th</strong>e paper industry are needed wi<strong>th</strong> regards to <strong>th</strong>e following:<br />
configuration <strong>of</strong> recovery boilers wi<strong>th</strong> respect to liquor firing, efficient <strong>th</strong>ree zone air distribution,<br />
auxiliary fuel furn<strong>ac</strong>e construction corrosion, protection and steam pressure. Earlier, boilers were<br />
giving steam pressures <strong>of</strong> 20 kg/cm 2 but mills are now able to produce steam pressures <strong>of</strong> 40-60<br />
kg/cm 2 . Wi<strong>th</strong> new designs, boilers can now produce high pressure steam <strong>of</strong> 100 kg/cm 2 . By<br />
incorporating <strong>th</strong>e above-mentioned improvement, <strong>th</strong>e West Coast Paper Mills in India is now<br />
going for recovery wi<strong>th</strong> steam pressure <strong>of</strong> 80 kg/cm 2 .<br />
3. Introduction <strong>of</strong> on-line measurement and control system<br />
On-line measurements and control systems have lately been introduced in Indian paper m<strong>ac</strong>hines<br />
in <strong>th</strong>e Tribeni and HNL paper mills. O<strong>th</strong>er mills are following suit. The introduction <strong>of</strong> such<br />
systems aids in <strong>th</strong>e following:<br />
- high fiber savings<br />
- improved and consistent quality <strong>of</strong> paper<br />
- optional moisture content<br />
- reduction in energy consumption due to high % <strong>of</strong> moisture in paper.<br />
Digesters<br />
It has been observed <strong>th</strong>at <strong>th</strong>e use <strong>of</strong> low liquor to material ratio is quite effective in reducing <strong>th</strong>e<br />
energy consumption in <strong>th</strong>e digester section. In small agro-based pulp mills, <strong>th</strong>is is <strong>ac</strong>hieved by <strong>th</strong>e<br />
constant monitoring <strong>of</strong> low moisture in <strong>th</strong>e raw material, maintaining a high concentration <strong>of</strong> <strong>th</strong>e<br />
cooking liquor (100g/li) and a high temperature or shorter cooking cycle.<br />
Installation <strong>of</strong> screw press for efficient washing <strong>of</strong> pulp<br />
In conventional washing systems, non-woody raw materials are more difficult to wash compared<br />
to woody raw materials. The usual equipment being used is <strong>th</strong>e counter current multistage v<strong>ac</strong>uum<br />
drum filters. It is observed, however, <strong>th</strong>at for every percent increase in solids, a savings potential <strong>of</strong><br />
25 tons <strong>of</strong> steam per day in a 100 tons per day pulp mill is possible. Table 6.2.10 shows how <strong>th</strong>e<br />
steam requirement in evaporators is reduced wi<strong>th</strong> an increase in inlet solid concentrations.<br />
In one <strong>of</strong> <strong>th</strong>e straw-based mills, it was observed <strong>th</strong>at <strong>th</strong>e installation <strong>of</strong> <strong>th</strong>e screw press before <strong>th</strong>e<br />
v<strong>ac</strong>uum washer increased <strong>th</strong>e specific loading rate and initial concentration <strong>of</strong> weak bl<strong>ac</strong>k liquor to<br />
<strong>th</strong>e evaporator. This reduced <strong>th</strong>e steam requirement during <strong>th</strong>e evaporation process. Table 6.2.11<br />
shows <strong>th</strong>e effects <strong>of</strong> process modification.
98 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Table 6.2.10 Steam requirements wi<strong>th</strong> varying inlet and outlet concentrations<br />
White bl<strong>ac</strong>k liquor Final concentration Steam requirement<br />
(%)<br />
(t/t <strong>of</strong> pulp)<br />
6 40 10.6<br />
42 10.7<br />
45 10.8<br />
8 40 7.5<br />
42 7.6<br />
45 7.7<br />
10 40 5.6<br />
42 5.7<br />
45 5.8<br />
Table 6.2.11 Conventional and screw pressing followed by conventional washing<br />
Mode Specific loading<br />
rate<br />
BDMT/m<br />
Conventional washer (3-<br />
stage)<br />
Screw press followed by<br />
conventional washer (3stage)<br />
Bl<strong>ac</strong>k liquor<br />
solids<br />
%<br />
Chemical loss<br />
kg NaOH/t<br />
1.46 10 18<br />
1.73 12 12<br />
High solids evaporation <strong>th</strong>rough <strong>th</strong>ermal depolymerization<br />
The energy in terms <strong>of</strong> steam <strong>th</strong>at can be generated per ton <strong>of</strong> bl<strong>ac</strong>k liquor solids is dependent on<br />
<strong>th</strong>e concentration <strong>of</strong> bl<strong>ac</strong>k liquor <strong>th</strong>at is fired in <strong>th</strong>e recovery boiler. Since it is difficult to handle<br />
highly viscous bl<strong>ac</strong>k liquor from non-woody materials in <strong>th</strong>e evaporator, heat treatment <strong>of</strong> bl<strong>ac</strong>k<br />
liquor at temperatures higher <strong>th</strong>an <strong>th</strong>e cooking temperature could reduce <strong>th</strong>e viscosity <strong>of</strong> bl<strong>ac</strong>k<br />
liquor tremendously, making it possible for <strong>th</strong>e bl<strong>ac</strong>k liquor to evaporate, leaving behind some<br />
70% solids. The advantages <strong>of</strong> <strong>th</strong>e bl<strong>ac</strong>k liquor treatment are <strong>th</strong>e following:<br />
- Instead <strong>of</strong> a 50-55% <strong>th</strong>ermal efficiency for 55% bl<strong>ac</strong>k liquor solids, <strong>th</strong>e net <strong>th</strong>ermal<br />
efficiency is likely to re<strong>ac</strong>h 70% in cases <strong>of</strong> 65% solid concentration.<br />
- The use <strong>of</strong> direct cont<strong>ac</strong>t evaporator is eliminated, <strong>th</strong>ereby reducing gaseous pollution.<br />
C. Energy generation<br />
Wi<strong>th</strong> regards to energy generation, small paper plants operating wi<strong>th</strong> lower cap<strong>ac</strong>ity boilers<br />
consume waste fuels such as rice husk, bagasse, etc., and depend greatly on purchased power.<br />
Large mills on <strong>th</strong>e o<strong>th</strong>er hand, generate part <strong>of</strong> <strong>th</strong>eir own power <strong>th</strong>rough cogeneration.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 99<br />
Commonly-used boilers are <strong>th</strong>e stoker-fired boilers which may ei<strong>th</strong>er be <strong>th</strong>e chain grate or<br />
spreader-stoker type, wi<strong>th</strong> cap<strong>ac</strong>ities ranging from 6-80 t/h. Most medium and large-size mills<br />
currently have installed fluidized bed combustion (FBC) boilers or are in <strong>th</strong>e process <strong>of</strong> converting<br />
spreader stoker to FBC boilers.<br />
6.2.6 Status <strong>of</strong> <strong>th</strong>e application <strong>of</strong> new technologies<br />
The extent <strong>of</strong> employment <strong>of</strong> energy-efficient and environmentally sound technologies (EEESTs)<br />
in <strong>th</strong>e pulp and paper mills <strong>of</strong> India is summarized in Table 6.2.12.<br />
Table 6.2.12 EEESTs in <strong>th</strong>e pulp and paper mills <strong>of</strong> India<br />
<strong>Technology</strong> No. <strong>of</strong> mills using <strong>th</strong>e technology<br />
Palman chippers 7<br />
Kamyr continuous digesters 2<br />
Pandia continuous digesters 3<br />
Oxidative extr<strong>ac</strong>tion (OE) 4<br />
Elemental chlorine-free ble<strong>ac</strong>hing 3<br />
Double disk refiners 50% <strong>of</strong> <strong>th</strong>e mills<br />
Twin wire m<strong>ac</strong>hines 5<br />
Free flowing falling film evaporators 3<br />
Long tube vertical type evaporators most integrated mills have LTV<br />
evaporators<br />
High pressure boilers (40-60 kg/cm) 5<br />
Electrostatic precipitator 70% <strong>of</strong> <strong>th</strong>e integrated mills<br />
Lime sludge reburning 5<br />
<strong>Full</strong> fledged effluent treatment system 80-90% <strong>of</strong> <strong>th</strong>e integrated mills and some<br />
selected medium and small-sized mills<br />
Despite <strong>th</strong>e changes occurring wi<strong>th</strong> regards to environmental consciousness, public concerns and<br />
customer preferences in <strong>th</strong>e country, <strong>th</strong>e pulp and paper industry is still in a difficult position to<br />
impose total environmental management and undergo environmental control modifications in <strong>th</strong>e<br />
f<strong>ac</strong>ilities. Never<strong>th</strong>eless, some new trends are currently being realized in a number <strong>of</strong> paper mills in<br />
<strong>th</strong>e country in order to combat environmental problems (see Table 6.2.12).
100 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
6.3 COUNTRY REPORT: PHILIPPINES<br />
6.3.1 Introduction<br />
All industrial processes generate waste. Since no production system can transform all input<br />
resources completely into end-products, waste generation is inevitable. Problems arise when <strong>th</strong>ese<br />
wastes are discharged in excess <strong>of</strong> what <strong>th</strong>e environment can absorb.<br />
The industrial sector which <strong>ac</strong>counts for a large share in <strong>th</strong>e country’s energy consumption, is also<br />
a major source <strong>of</strong> environmental pollution. Industrial pollution has earlier been considered a local<br />
problem but is today recognized as regional as well as global. Common sources <strong>of</strong> industrial<br />
pollution are <strong>th</strong>e waste water used in <strong>th</strong>e manuf<strong>ac</strong>turing process and <strong>th</strong>e emissions from<br />
combustion <strong>of</strong> fossil fuel. There is a wide array <strong>of</strong> technically feasible abatement measures ranging<br />
from efficiency improvement in <strong>th</strong>e process to <strong>th</strong>e more common and usually more expensive end<strong>of</strong>-pipe<br />
pollution abatement technologies.<br />
The pulp and paper industry is one <strong>of</strong> <strong>th</strong>e industrial sector’s high energy consumers and major<br />
contributors in pollution. Attention to <strong>th</strong>e pulp and paper industry, <strong>th</strong>erefore, deserves a high<br />
priority. This section looks into <strong>th</strong>e technological status <strong>of</strong> <strong>th</strong>e pulp and paper industry <strong>of</strong> <strong>th</strong>e<br />
Philippines wi<strong>th</strong> regards to energy efficiency and environmental soundness. Through <strong>th</strong>e historical<br />
and present techno-economic data <strong>of</strong> <strong>th</strong>e industry, <strong>th</strong>e potential for improving <strong>th</strong>e current status <strong>of</strong><br />
technologies for energy and environmental management is analyzed.<br />
6.3.2 Technological trajectory <strong>of</strong> <strong>th</strong>e paper industry in <strong>th</strong>e Philippines<br />
6.3.2.1 Structure <strong>of</strong> <strong>th</strong>e paper industry<br />
Pulp and paper production in <strong>th</strong>e Philippines was pioneered by Compania de Cellulosa de Filipinas<br />
when it established an integrated pulp and paper mill in 1948 in Bais, Negros Occidental. The mill<br />
which produced 10 tons <strong>of</strong> bond paper per day using bagasse as raw material is still in operating<br />
condition. Ano<strong>th</strong>er pioneer in <strong>th</strong>e paper industry was established in 1950 in Metro Manila to<br />
operate a second-hand board m<strong>ac</strong>hine. This m<strong>ac</strong>hine is still operational and currently produces<br />
chipboard.<br />
A number <strong>of</strong> paper mills were established during <strong>th</strong>e 1950s and <strong>th</strong>e early 1960s when <strong>th</strong>e industry<br />
had to contend wi<strong>th</strong> two sets <strong>of</strong> import duty levels - a lower rate for pulp and a higher rate for<br />
finished paper and brand products. This encouraged <strong>th</strong>e mills to utilize <strong>th</strong>e cheaper imported raw<br />
materials. In effect, plans to build pulping f<strong>ac</strong>ilities for most <strong>of</strong> <strong>th</strong>e mills never materialized.<br />
Several non-integrated paper mills were established during <strong>th</strong>e 1970s and 1980s but <strong>th</strong>ese were<br />
based mainly on imported and local recycled waste paper. The list <strong>of</strong> paper mills in <strong>th</strong>e country<br />
and <strong>th</strong>eir dates <strong>of</strong> establishment are shown in Annex 1.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 101<br />
From 1978 to 1991, paper production in <strong>th</strong>e Philippines remained flat. Consumption on one hand<br />
increased from 440,000 tons in 1978 to 753,000 tons in 1993 (Table 6.3.1). To meet increasing<br />
demand, <strong>th</strong>e country had to rely on imports. In contrast, production <strong>of</strong> paper and board in o<strong>th</strong>er<br />
ASEAN countries rose from 820,000 to 2,100,000 tons wi<strong>th</strong> marginal increase in net imports<br />
during <strong>th</strong>e same ten-year period.<br />
Despite <strong>th</strong>e problem <strong>of</strong> power shortages in <strong>th</strong>e last two years, <strong>th</strong>e industry managed to continue<br />
operations and, aided by resilient domestic market, was able to post moderate gains. Total<br />
production <strong>of</strong> <strong>th</strong>e country’s operating mills re<strong>ac</strong>hed 490,000 tons in 1992 and increased by 6% to<br />
518,000 tons in 1993.<br />
Table 6.3.1 Evolution <strong>of</strong> paper industry: total paper and paperboard (10 3 tons)<br />
Year Installed<br />
Cap<strong>ac</strong>ity<br />
Production Consumption Imports<br />
1987 439 319.5 475.0 200.8<br />
1988 506 341.0 493.9 193.0<br />
1989 564 345.0 554.6 216.4<br />
1990 579 325.0 481.6 205.3<br />
1991 579 392.0 626.0 245.2<br />
1992 635 489.0 743.1 279.5<br />
1993 650 517.5 753.1 279.5<br />
Source: Aragon, P.M., Country Focus.<br />
A. Production cap<strong>ac</strong>ity<br />
From a 1989 survey, <strong>th</strong>e industry coverage was 33 pulp and paper mills, wi<strong>th</strong> 4 integrated mills<br />
(shown in Table 6.3.2) and 5 pulp manuf<strong>ac</strong>turers (Table 6.3.3). The remaining 24 are nonintegrated<br />
paper mills. Exclusive <strong>of</strong> two non-operating mills, <strong>th</strong>e total production cap<strong>ac</strong>ity <strong>of</strong> <strong>th</strong>e<br />
integrated mills is 410,000 tons per annum.<br />
The total pulp cap<strong>ac</strong>ity <strong>of</strong> <strong>th</strong>e Philippines is about 289,000 tons per annum while aggregate paper<br />
cap<strong>ac</strong>ity is approximately 611,000 tons per year. In view <strong>of</strong> several closures, <strong>th</strong>e average annual<br />
operating cap<strong>ac</strong>ities for pulp and paper production are 223,000 tons and 526,000 tons, respectively<br />
(Table 6.3.4).<br />
The industry structure is very small compared to international standards. Of <strong>th</strong>e 28 paper mills,<br />
only 3 have a cap<strong>ac</strong>ity <strong>of</strong> over 50,000 tons per annum (Table 6.3.5). The average size <strong>of</strong> mills<br />
ranges from 10,000 to 15,000 tons per annum. The industry structure is also outmoded and as a<br />
result, suffers from leng<strong>th</strong>y m<strong>ac</strong>hine downtime due to difficulties in obtaining outdated<br />
repl<strong>ac</strong>ement parts.
102 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Table 6.3.2 Integrated pulp and paper mills in <strong>th</strong>e Philippines, 1989<br />
Company/Mill Pulp Paper<br />
Cap<strong>ac</strong>ity<br />
(10 3 Materials Cap<strong>ac</strong>ity<br />
t/year)<br />
(10 3 Main Grades<br />
t/year)<br />
PICOP 180 Mech, UKP, 150 Newsprint, Linerboard,<br />
BKP<br />
Corrugated Medium<br />
Central Azucarera 9 Bagasse 14 Printing<br />
United Pulp & Paper 16 Bagasse 31 S<strong>ac</strong>k Kraft, Corrug.<br />
Menzi Dev’t. Corp. 3 Ab<strong>ac</strong>a 7<br />
Medium, Linerboard<br />
Printing & Writing<br />
Table 6.3.3 Pulp mills in <strong>th</strong>e Philippines, 1989<br />
Company/Mill Cap<strong>ac</strong>ity (10 3 t/year) Materials<br />
Albay Agro-Ind’l. Dev’t. Corp. 1 Ab<strong>ac</strong>a<br />
Canlubang Pulp Mfg. Company 4.5 Ab<strong>ac</strong>a<br />
Cellophil Resources Corporation 66 Wood Pulp<br />
Isarog Pulp and Paper Co. 4.5 Ab<strong>ac</strong>a<br />
PICOP 5 Ab<strong>ac</strong>a<br />
Table 6.3.4 Total pulp and paper mill cap<strong>ac</strong>ities in <strong>th</strong>e Philippines, 1989<br />
Mill Categories Cap<strong>ac</strong>ity (10 3 t/year)<br />
Pulp Paper<br />
Integrated mills 208 202<br />
Pulp mills 81 -<br />
Paper mills - 409<br />
Total cap<strong>ac</strong>ities 289 611<br />
Operational cap<strong>ac</strong>ities 223 536<br />
Table 6.3.5 Philippine paper mills categorized by rated cap<strong>ac</strong>ity (t/year)<br />
Rated Cap<strong>ac</strong>ity Number <strong>of</strong> paper mills<br />
Below 10,000 10<br />
10,000 to 20,000 10<br />
20,000 to 50,000 5<br />
50,000 & above 3<br />
B. Paper m<strong>ac</strong>hines<br />
There are currently 45 paper m<strong>ac</strong>hines in <strong>th</strong>e country wi<strong>th</strong> a total cap<strong>ac</strong>ity <strong>of</strong> 540,000 tons per<br />
annum, or an average <strong>of</strong> 12,000 tons annually (Table 6.3.6).
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 103<br />
Table 6.3.6 Paper m<strong>ac</strong>hine structure in <strong>th</strong>e Philippines in terms <strong>of</strong> cap<strong>ac</strong>ity (10 3 t/year),<br />
trim wid<strong>th</strong> per cm, and start-up year<br />
PM cap<strong>ac</strong>ity Operating Total paper % Share<br />
m<strong>ac</strong>hines<br />
cap<strong>ac</strong>ity<br />
below 10 33 166 31.0<br />
10 - 19 7 102 19.0<br />
20 - 29 1 27 5.0<br />
30 - 39 1 31 5.8<br />
40 - 49 - - -<br />
50 - 59 - - -<br />
60 - 69 2 128 23.9<br />
over 69 1 82 15.3<br />
Total 45 536 100.0<br />
PM trim/cm<br />
below 201 22 132 24.6<br />
201 - 300 16 118 22.0<br />
301 - 400 5 144 26.9<br />
401 - 500 - - -<br />
501 - 600 1 60 11.2<br />
over 600 1 82 15.3<br />
Total 45 536 100.0<br />
Start-up Year<br />
before 1960 7 57 10.6<br />
1960s 19 132 24.6<br />
1970s 10 240 44.8<br />
1980s 9 107 20.0<br />
Total 45 536 100.0<br />
As can be seen in Table 6.3.6, only <strong>th</strong>ree <strong>of</strong> <strong>th</strong>e m<strong>ac</strong>hines operate at a minimum <strong>of</strong> 60,000 tons per<br />
year, representing less <strong>th</strong>an 40 percent <strong>of</strong> <strong>th</strong>e total industry cap<strong>ac</strong>ity. Most <strong>of</strong> <strong>th</strong>e m<strong>ac</strong>hines were<br />
bought second-hand and are very small bo<strong>th</strong> in terms <strong>of</strong> cap<strong>ac</strong>ity and wid<strong>th</strong>. Only two have a<br />
wid<strong>th</strong> greater <strong>th</strong>an 5 meters. The m<strong>ac</strong>hines are also very old. However, it is quite difficult to<br />
establish <strong>th</strong>e ex<strong>ac</strong>t age <strong>of</strong> <strong>th</strong>ese m<strong>ac</strong>hines because almost all have been bought second-hand.<br />
Twenty m<strong>ac</strong>hines have reportedly been installed during <strong>th</strong>e past 20 years.<br />
Of <strong>th</strong>e 45 operating m<strong>ac</strong>hines, 5 can easily absorb 50 percent <strong>of</strong> <strong>th</strong>e total annual production<br />
cap<strong>ac</strong>ity. In f<strong>ac</strong>t, <strong>th</strong>e 2 biggest m<strong>ac</strong>hines (wi<strong>th</strong> a trim exceeding 500 cm) have a combined cap<strong>ac</strong>ity<br />
constituting 26.5 percent <strong>of</strong> total. Essentially, <strong>th</strong>e country’s aggregate paper requirements may be<br />
supplied by only ten medium-sized (not necessarily modern) paper m<strong>ac</strong>hines. Table 6.3.7 presents<br />
<strong>th</strong>e status <strong>of</strong> <strong>th</strong>e country’s paper m<strong>ac</strong>hines in 1989, relative to <strong>th</strong>at <strong>of</strong> <strong>th</strong>e o<strong>th</strong>er ASEAN countries.
104 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Table 6.3.7 Total cap<strong>ac</strong>ities <strong>of</strong> paper m<strong>ac</strong>hines in ASEAN countries by mill cap<strong>ac</strong>ity,<br />
age, and wid<strong>th</strong>, 1989 (10 3 t/year)<br />
Distribution Indonesia Malaysia Philippines Singapore Thailand Total<br />
PM Cap<strong>ac</strong>ity<br />
below 20,000 455 136 294 42 330 1257<br />
21,000-40,000 464 - 103 77 161 805<br />
41,000-60,000 155 - 60 60 50 325<br />
61,000-80,000 285 130 72 - 220 707<br />
over 80,000 225 - 82 - 200 507<br />
Total 1584 266 611 179 961 3601<br />
# <strong>of</strong> m<strong>ac</strong>hines 90 27 52 13 78 260<br />
Average cap<strong>ac</strong>ity 17.6 9.9 11.8 13.8 12.3 13.9<br />
Start-up year<br />
before 1950s 375 82 160 38 116 771<br />
1950s 10 - 55 - 6 71<br />
1960s 156 13 111 1 162 443<br />
1970s 281 26 238 47 287 879<br />
1980s 762 145 47 93 390 1437<br />
Total 1584 266 611 179 961 3601<br />
Median age (yr.) 10 8 21 9 12 13<br />
Wire wid<strong>th</strong> (m)<br />
below 3 602 121 301 64 540 1628<br />
3 - 5 617 15 168 115 351 1266<br />
5 - 7 140 130 142 - 70 482<br />
over 7 225 - - - 225<br />
Total 1584 266 611 179 961 3601<br />
Median wid<strong>th</strong> (m) 3.35 3.80 3.06 3.46 2.25 3.02<br />
Local mills l<strong>ac</strong>k <strong>th</strong>e simplest instrumentation and process control systems. The speed <strong>of</strong> most<br />
m<strong>ac</strong>hines is quite slow and consumption <strong>of</strong> energy is high. They are also ill-equipped in terms <strong>of</strong><br />
environmental protection. Prolonged shutdowns have become common due to l<strong>ac</strong>k <strong>of</strong> spare parts<br />
and inadequate engineering/consulting companies. Safety standards are generally low and fatal<br />
<strong>ac</strong>cidents frequently occur.<br />
6.3.2.2 <strong>Technology</strong><br />
Standard manuf<strong>ac</strong>turing technology is being used in <strong>th</strong>e industry. Given <strong>th</strong>e papermaking<br />
equipment and f<strong>ac</strong>ilities available and <strong>th</strong>e flexible requirements <strong>of</strong> <strong>th</strong>e domestic market, <strong>th</strong>is is<br />
found to be adequate for <strong>th</strong>e industry. There appears to be an adequate supply <strong>of</strong> trained<br />
technicians and skilled personnel. Some big mills also engage foreign technicians as needed.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 105<br />
Based on <strong>th</strong>e study commissioned by <strong>th</strong>e Development Bank <strong>of</strong> <strong>th</strong>e Philippines (DBP) in 1992, it<br />
was observed <strong>th</strong>at <strong>th</strong>e technological framework <strong>of</strong> <strong>th</strong>e pulp and paper industry is essentially<br />
structured as follows:<br />
- Only 5 <strong>of</strong> <strong>th</strong>e country’s operating mills are integrated wi<strong>th</strong> pulp production, representing<br />
36% <strong>of</strong> total production cap<strong>ac</strong>ity.<br />
- The industry is heavily dependent on imported raw materials, particularly virgin pulp,<br />
waste paper, and papermaking chemicals.<br />
- Existing paper m<strong>ac</strong>hines are generally small and do not have economies <strong>of</strong> scale to<br />
compete wi<strong>th</strong> foreign products. Even <strong>th</strong>e 3 biggest m<strong>ac</strong>hines representing 40% <strong>of</strong> <strong>th</strong>e<br />
total production cap<strong>ac</strong>ity do not have <strong>th</strong>e economies <strong>of</strong> scale to be internationally<br />
competitive. Of <strong>th</strong>e 45 operating m<strong>ac</strong>hines, 40 have production cap<strong>ac</strong>ities below 20,000<br />
tons.<br />
- Most <strong>of</strong> <strong>th</strong>e paper m<strong>ac</strong>hines are old and obsolete. Many were bought second-hand and<br />
were already outmoded on start-up.<br />
- One reason for <strong>th</strong>e industry’s low operating efficiency is <strong>th</strong>e difficulty to find spare parts<br />
for <strong>th</strong>e outmoded m<strong>ac</strong>hines. Shutdowns due to l<strong>ac</strong>k <strong>of</strong> spare parts are common among<br />
local mills.<br />
- High energy consumption is also an effect <strong>of</strong> obsolete m<strong>ac</strong>hinery. Only a handful <strong>of</strong> <strong>th</strong>e<br />
local m<strong>ac</strong>hines have some sort <strong>of</strong> heat recovery system.<br />
- High energy costs, in turn, result in high production costs. To compare, a modern<br />
newsprint paper mill based on waste paper consumes about 900 to 1,000 kWh per ton,<br />
while a standard Philippine mill consumes 1,275 kWh per ton.<br />
- Modern integrated process control devices which are standard equipment for all m<strong>ac</strong>hines<br />
in Western countries are not available in Philippine mills. Local mills are basically<br />
equipped wi<strong>th</strong> conventional pneumatic instrumentation, only 3 m<strong>ac</strong>hines use<br />
computerized weight and moisture control systems, and a few operate wi<strong>th</strong>out any kind<br />
<strong>of</strong> instrumentation at all.<br />
- Most m<strong>ac</strong>hines operate at speeds below 500 m/min. The fastest newsprint m<strong>ac</strong>hine runs<br />
at 760 m/min, slower <strong>th</strong>an <strong>th</strong>e speed <strong>of</strong> modern m<strong>ac</strong>hines, which is 1,000 m/min.<br />
- Faulty process designs result from l<strong>ac</strong>k <strong>of</strong> engineering and technical expertise specific to<br />
<strong>th</strong>e pulp and paper sub-sector. Extra operation costs are <strong>th</strong>us incurred, fur<strong>th</strong>er<br />
aggravating <strong>th</strong>e low operating efficiency <strong>of</strong> <strong>th</strong>e industry.
106 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
- Safety standards in most mills are very low and fatal <strong>ac</strong>cidents frequently occur.<br />
Unprotected rotating parts, roll nips and pulpers are safety hazards in many mills.<br />
6.3.3 Evolution <strong>of</strong> energy efficiency in <strong>th</strong>e pulp and paper industry <strong>of</strong> <strong>th</strong>e Philippines<br />
6.3.3.1 Energy pr<strong>of</strong>ile<br />
The pulp and paper industry is an energy-intensive industry where energy consumption varies wi<strong>th</strong><br />
respect to <strong>th</strong>e manuf<strong>ac</strong>turing operations and processes involved. From 1984 to 1992, figures show<br />
an increasing trend in <strong>th</strong>e total consumption <strong>of</strong> energy for <strong>th</strong>e pulp and paper sector. (Figure<br />
6.3.1). Oil, non-oil and electricity consumption comprise 40%, 35% and 25%, respectively, <strong>of</strong> <strong>th</strong>e<br />
total energy consumption in <strong>th</strong>e industry.<br />
toe<br />
450000<br />
400000<br />
350000<br />
300000<br />
250000<br />
200000<br />
150000<br />
100000<br />
50000<br />
0<br />
1984 1985 1986 1987 1988 1989 1990 1991 1992<br />
Oil Non-oil Electricity Total Energy<br />
Figure 6.3.1 Historical energy consumption <strong>of</strong> <strong>th</strong>e pulp and paper sector in <strong>th</strong>e Philippines<br />
(koe, 1984 to 1992)<br />
The industry is also considered one <strong>of</strong> <strong>th</strong>e high fuel oil consuming sectors among <strong>th</strong>e Philippine<br />
industries wi<strong>th</strong> a share <strong>of</strong> 2.5% <strong>of</strong> <strong>th</strong>e total industrial fuel oil consumption. The pr<strong>of</strong>ile on energy<br />
use as is described below was based on six mills studied (Table 6.3.8 and Figure 6.3.2).<br />
A. Energy consumption<br />
Total annual energy consumption in six plants is 182,258 toe. This is broken down into 141,154<br />
toe (77%) bunker fuel and 284,64 toe (16%) electricity, and 12,640 toe (7%) for o<strong>th</strong>ers. The energy<br />
requirement is used mainly as heat for steam generation/process heating and as mechanical power<br />
to run <strong>th</strong>e plants’ electrical motors.<br />
Consumption <strong>of</strong> energy depends largely on <strong>th</strong>e type <strong>of</strong> m<strong>ac</strong>hine, its process design, operating<br />
efficiency, and production rate. Normally, smaller m<strong>ac</strong>hines consume less energy because <strong>th</strong>ey
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 107<br />
involve simpler processes wi<strong>th</strong> less automation. However, specific energy consumption is higher<br />
in smaller production units. As a result, energy utilization <strong>of</strong> local mills is 20 to 40% higher <strong>th</strong>an<br />
standard levels.<br />
B. Energy source mix<br />
The energy use pattern in <strong>th</strong>e six mills is based mainly on electricity and oil sources. One firm uses<br />
non-oil energy sources in <strong>th</strong>e form <strong>of</strong> waste wood and bl<strong>ac</strong>k liquor. More <strong>th</strong>an half <strong>of</strong> <strong>th</strong>e energy<br />
input in <strong>th</strong>e industry is used to generate steam for process heating. Supply <strong>of</strong> electricity differs<br />
among <strong>th</strong>e plants. Most companies utilize electricity which is entirely supplied from outside, while<br />
one company internally generates a small portion <strong>of</strong> its electricity requirements.<br />
Table 6.3.8 Annual energy consumption <strong>of</strong> six mills <strong>of</strong> <strong>th</strong>e Philippine paper industry<br />
Bunker Fuel Electricity O<strong>th</strong>ers Total<br />
Company 10 3 liters toe MWh toe GJ toe toe<br />
A 2224 2202 11197 955 3157<br />
B 20700 20500 45528 3884 24384<br />
C 1104 1093 1877 160 1253<br />
D 10490 10388 84530 7211 17599<br />
E 4056 4016 14853 1267 5283<br />
F 10971 102955 175680 14987 533398 12640 130582<br />
Total 142544 141154 333665 28464 533398 12640 182258<br />
77.45% 15.62% 6.93% 100.00%<br />
Average 23757 28231 55611 5693 36452<br />
Bunker<br />
Fuel<br />
77%<br />
Electricity<br />
16%<br />
O<strong>th</strong>ers<br />
7%<br />
Figure 6.3.2 Distribution <strong>of</strong> annual energy consumption <strong>of</strong> six Philippine paper mills<br />
C. Energy application<br />
About 72% <strong>of</strong> energy input goes for process heating. The use <strong>of</strong> electricity, mostly in electric<br />
motors, <strong>ac</strong>counts for 23%. O<strong>th</strong>er small applications such as materials handling and transportation,<br />
which utilizes petroleum products, <strong>ac</strong>count for 5% (Table 6.3.9).
108 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Table 6.3.9 Energy utilization pr<strong>of</strong>ile <strong>of</strong> 3 energy-intensive industries in <strong>th</strong>e Philippines<br />
Energy Applications (%) Paper<br />
Industry<br />
Cement (Dry) Steel/Metal<br />
Mechanical Power Drive 23% 24% 30.3%<br />
Process Heating 72% 74.5% 66.0%<br />
Transport/Handling 5% 0.5% 1.5%<br />
Lighting/Airconditioning<br />
1.0% 2.2%<br />
Total 100.00% 100.00% 100.00%<br />
D. Specific Energy Consumption<br />
On <strong>th</strong>e average, energy consumed in six mills in <strong>th</strong>e country is about 475.6 kgoe/t <strong>of</strong> paper<br />
produced. This ratio can be broken down into 364.5 kgoe (bunker fuel) per ton paper and 1,084<br />
kWh <strong>of</strong> electricity inputs per ton (Table 6.3.10).<br />
Table 6.3.10 Specific energy consumption <strong>of</strong> <strong>th</strong>e six paper mills in <strong>th</strong>e Philippines<br />
Company SFC in kgoe/t SELC in kWh/t SEC in kgoe/t<br />
A 310.9 1,580.0 445.6<br />
B 512.9 1,139.0 612.5<br />
C 239.2 410.8 274.3<br />
D 131.2 1,067.3 240.1<br />
E 306.5 1,133.5 403.2<br />
F 686.3 1,171.2 877.0<br />
Average 364.5 1,083.6 475.6<br />
E. Energy cost<br />
A previous survey revealed <strong>th</strong>at from 1983 to 1986, fuels purchased <strong>ac</strong>counted for 48% <strong>of</strong> <strong>th</strong>e total<br />
<strong>of</strong> <strong>th</strong>e sector, while electricity <strong>ac</strong>counted for 52% (Table 6.3.11). The average cost <strong>of</strong> fuels and<br />
electricity purchased during <strong>th</strong>e same period was P728,669 and P804,813, respectively. At present,<br />
<strong>th</strong>e cost <strong>of</strong> bunker fuel oil which is <strong>th</strong>e main source <strong>of</strong> energy for <strong>th</strong>e industry, ranges from P2.65<br />
to P2.99 per liter. Electricity cost varies between P1.275 to P2.86 per kWh.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 109<br />
Table 6.3.11 Historical energy cost data <strong>of</strong> <strong>th</strong>e Philippine paper industry (10 3 US$)<br />
Year Fuels Purchased Electricity Purchased Total<br />
1983 31937 25162 58377<br />
1984 50786 33440 86258<br />
1985 17614 28594 46913<br />
1986 16250 41574 58473<br />
Average 29147 32193 62505<br />
% <strong>of</strong> Total 48% 52% 100%<br />
Source: National Statistics Office, Annual Survey <strong>of</strong> Establishments<br />
6.3.4 Environmental externalities <strong>of</strong> <strong>th</strong>e pulp and paper industry <strong>of</strong> <strong>th</strong>e Philippines<br />
6.3.4.1 Environmental concerns<br />
The industry is heavily concentrated in Metro Manila wi<strong>th</strong> strong pressure to establish adequate<br />
pollution control measures. No mill can be expected to comply wi<strong>th</strong> <strong>th</strong>e required environmental<br />
protection standards due to <strong>th</strong>e high investment needed for proper pollution control measures.<br />
A. Water pollution<br />
The mills in <strong>th</strong>e Philippines are mostly old and obsolete wi<strong>th</strong> limited pollution control f<strong>ac</strong>ilities.<br />
The problem <strong>of</strong> pollution is more pronounced in <strong>th</strong>e Metro Manila area where most <strong>of</strong> <strong>th</strong>e mills<br />
are located. To worsen matters, Metro Manila has no common sewer system to ensure adequate<br />
waste water treatment. The main pollutants for <strong>th</strong>e pulp and paper industry are <strong>th</strong>e biological<br />
oxygen demand (BOD5) and <strong>th</strong>e total suspended solids (TSS).<br />
Water pollution in Metro Manila has become very alarming. Bo<strong>th</strong> <strong>th</strong>e industrial sector and private<br />
individuals are guilty <strong>of</strong> contributing to <strong>th</strong>e city’s pollution problem. The huge influx <strong>of</strong> people<br />
from <strong>th</strong>e provinces who do not have adequate sanitary f<strong>ac</strong>ilities aggravates <strong>th</strong>e situation.<br />
Meanwhile, most <strong>of</strong> <strong>th</strong>e old paper mills only have filters for fiber recovery.<br />
Effluent water standards in <strong>th</strong>e Philippines are set as ambient combinations. In contrast, o<strong>th</strong>er<br />
pulp and paper producing countries base <strong>th</strong>eir standards on <strong>th</strong>e kilogram <strong>of</strong> pollutant discharged<br />
per ton <strong>of</strong> pulp and paper produced. There is no point, <strong>th</strong>erefore, in comparing <strong>th</strong>e two standards.<br />
The ambient water concentration applied in <strong>th</strong>e Philippines is, however, close to <strong>th</strong>e standard set in<br />
developed countries, particularly in <strong>th</strong>e USA.<br />
B. In-plant measures and external effluent water treatment<br />
Aside from minimized water consumption, recovery <strong>of</strong> fiber, energy and chemicals is equally<br />
important for paper mills. The most common measures to effect <strong>th</strong>is include <strong>th</strong>e following:
110 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
- collection and recirculation <strong>of</strong> clean, cool water<br />
- installation <strong>of</strong> a v<strong>ac</strong>uum sealing water system equipped wi<strong>th</strong> its own cooling tower and<br />
cooling water recirculation system<br />
- minimized flow <strong>of</strong> fresh water shower<br />
- use <strong>of</strong> mechanical seals to minimize sealing water consumption <strong>of</strong> pumps, agitators, and<br />
refiners<br />
- sufficient white water storage to equalize water flow and make operations more stable<br />
- use <strong>of</strong> effective fiber filters (fiber save all) or o<strong>th</strong>er equally effective recovery equipment<br />
to minimize fiber content in white water overflow<br />
The introduction <strong>of</strong> <strong>th</strong>e above measures is expected to enable paper mills in areas wi<strong>th</strong> insufficient<br />
fresh water supply to fur<strong>th</strong>er reduce water consumption to 10 m 3 per ton. In <strong>th</strong>e Philippines,<br />
average water consumption is higher, at 30 m 3 per ton. This is because most <strong>of</strong> <strong>th</strong>e mills are old<br />
and small, and it is very expensive to undertake a total rebuild. Also, waste paper is used as furnish<br />
in many mills and fresh water consumption is vital in <strong>th</strong>e operation <strong>of</strong> <strong>th</strong>ese mills to ensure better<br />
quality <strong>of</strong> paper produced.<br />
In-plant measures alone cannot adequately control <strong>th</strong>e presence <strong>of</strong> effluents and pollutants in<br />
water. It is necessary to undertake fur<strong>th</strong>er treatment <strong>of</strong> effluents before final discharge is made.<br />
Before discharge, effluents must first be externally treated. A primary clarifier can reduce TSS by<br />
as much as 70 to 95 percent but BOD can only be reduced marginally by <strong>th</strong>is me<strong>th</strong>od. A<br />
secondary treatment in an aerated lagoon or an <strong>ac</strong>tivated sludge plant is necessary to shrink BOD<br />
by about 50 to 90 percent TSS can be minimized fur<strong>th</strong>er by a secondary clarifier.<br />
Primary treatment should be compulsory for all pulp and paper mills starting from 1994.<br />
Secondary treatment including sludge handling should be obligated by <strong>th</strong>e year 2000 or earlier.<br />
Also, new paper mills are encouraged to be built outside Metro Manila.<br />
A 1992 DBP study showed <strong>th</strong>at environmental protection cost for <strong>th</strong>e projected paper cap<strong>ac</strong>ity in<br />
<strong>th</strong>e year 2000 is estimated to be about US$ 70 million. This includes in-plant measures, primary<br />
and secondary treatment, and sludge handling. Project financing could come from grants and<br />
long-term loans sourced from international financing institutions. The total investment for<br />
installing environmental control measures for <strong>th</strong>e five mills in 1992 is summarized in Table 6.3.12.<br />
C. Emissions to <strong>th</strong>e atmosphere<br />
Pr<strong>ac</strong>tically all paper mills in <strong>th</strong>e country have power boilers using Bunker C oil as fuel. Only one<br />
mill has a recovery boiler. The power boilers in most paper mills are generally small and mediumsized.<br />
When oil is burned, particulate matter and sulfur compounds are formed. The amount <strong>of</strong><br />
sulfur compound depends on <strong>th</strong>e amount <strong>of</strong> sulfur in oil.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 111<br />
Table 6.3.12 Investment for environmental control measures in 5 paper mills (10 3 US $)<br />
Case In-plant Primary Secondary Sludge Total<br />
measures treatment treatment handling<br />
A 190 1650 6100 1590 9530<br />
B 100 710 2210 860 3880<br />
C 85 370 860 760 2075<br />
D 100 660 1940 910 3610<br />
E 80 280 590 730 1680<br />
Reducing sulfuric emission may be realistically effected by <strong>th</strong>e use <strong>of</strong> sulfur-free fuel or fuel wi<strong>th</strong><br />
low sulfuric content and, treatment <strong>of</strong> flue gas after combustion. Using oil wi<strong>th</strong> low sulfur content<br />
is very effective in regulating sulfuric emissions. This kind <strong>of</strong> oil, however, is more expensive <strong>th</strong>an<br />
<strong>th</strong>e normal heavy oil. Electrostatic precipitators and scrubbers used for external treatment <strong>of</strong> flue<br />
gas are likewise effective but expensive. Particulate matter is pr<strong>ac</strong>tically eliminated (99 percent)<br />
wi<strong>th</strong> <strong>th</strong>e application <strong>of</strong> <strong>th</strong>e electrostatic precipitator. To reduce <strong>th</strong>e sulfuric compounds H 2S and<br />
SO 2, it is necessary to wash <strong>th</strong>e gases in scrubbers. This process reduces sulfur emission by as<br />
much as 90 to 95 percent.<br />
6.3.5 Potential for energy efficiency improvement and pollution abatement <strong>th</strong>rough<br />
technological changes<br />
6.3.5.1 Energy conservation opportunities<br />
The following are <strong>th</strong>e general observations and identified technologies wi<strong>th</strong> potentials for<br />
conserving energy for <strong>th</strong>e industry on <strong>th</strong>e basis <strong>of</strong> previous sectoral studies, surveys and energy<br />
audits conducted in <strong>th</strong>e pulp and paper industry.<br />
- Combustion tests conducted during recent energy audits showed <strong>th</strong>at majority <strong>of</strong> boilers<br />
were operating well wi<strong>th</strong>in or near <strong>th</strong>e optimum operating condition wi<strong>th</strong> boiler<br />
efficiencies varying from 72.4% to 87.7%.<br />
Four <strong>of</strong> <strong>th</strong>e six companies surveyed, have, in one time or ano<strong>th</strong>er, purchased and used a<br />
portable or on-line flue gas analyzer to monitor <strong>th</strong>e combustion performance <strong>of</strong> <strong>th</strong>eir<br />
boilers and adjust/fine tune <strong>th</strong>e air-fuel ratio. Of <strong>th</strong>ese four companies, only two have a<br />
functioning flue gas analyzer, one portable and one on-line. In <strong>th</strong>e o<strong>th</strong>er two companies,<br />
<strong>th</strong>e analyzers had not been operational for quite some time due to exhausted oxygen<br />
absorbent/cell. Most <strong>of</strong> <strong>th</strong>e companies get a free boiler efficiency testing from <strong>th</strong>e<br />
bunker fuel and/or fuel additive supplier on a mon<strong>th</strong>ly basis, while one company never<br />
had its boiler tested.<br />
- Boiler feedwater treatment is generally adequate, except in at least 3 companies where<br />
about 1/8 inch <strong>th</strong>ick scale was found inside <strong>th</strong>e boiler tubes during descaling.
112 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
- Fuel oil metering is usually done via day tank level monitoring. Only half <strong>of</strong> <strong>th</strong>e<br />
companies surveyed are maintaining boiler operation logsheets.<br />
- Condensate recovered from <strong>th</strong>e paper m<strong>ac</strong>hines and returned b<strong>ac</strong>k to <strong>th</strong>e boiler house<br />
varied from as low as 30% to as high as 85%.<br />
- Leaks were <strong>of</strong>ten noted on <strong>th</strong>e steam and condensate lines. Steam and condensate lines<br />
were also commonly observed to be inadequately insulated in most <strong>of</strong> <strong>th</strong>e plants visited.<br />
Insulation usually consists <strong>of</strong> wool blanket or asbestos wi<strong>th</strong> aluminum cladding.<br />
- There is at least one opportunity to investigate <strong>th</strong>e feasibility <strong>of</strong> installing waste heat<br />
recovery system in <strong>th</strong>e form <strong>of</strong> economizer to recover heat from boiler flue gas and a heat<br />
exchanger to recover heat from boiler blowdown.<br />
- Historical data is not always available to show <strong>th</strong>e distribution <strong>of</strong> electrical energy to <strong>th</strong>e<br />
paper m<strong>ac</strong>hines and o<strong>th</strong>er consumers. Fur<strong>th</strong>ermore, <strong>th</strong>ere is <strong>of</strong>ten a l<strong>ac</strong>k <strong>of</strong> watt-hour<br />
sub-metering system for <strong>th</strong>e major process areas/equipment. Electrical power distribution<br />
in a paper mill goes mainly to <strong>th</strong>e paper m<strong>ac</strong>hine to provide motive power, <strong>th</strong>e balance<br />
goes to <strong>th</strong>e boiler house, lighting, air conditioning, <strong>of</strong>fice equipment and miscellaneous<br />
loads.<br />
- Natural lighting is effectively utilized in most <strong>of</strong> <strong>th</strong>e companies surveyed. However, most<br />
installed skylights need to be cleaned/repl<strong>ac</strong>ed. The installation/retr<strong>of</strong>itting <strong>of</strong> reflectors<br />
on existing fluorescent fixtures is uncommon in <strong>th</strong>e industry. The rapid start type ballasts<br />
are still commonly used. Indoor lighting is predominated by fluorescent fixtures. A<br />
typical fixture is surf<strong>ac</strong>e-mounted and consists <strong>of</strong> two 4-watt fluorescent tubes, wi<strong>th</strong>out<br />
reflectors or diffusers but only a casing for <strong>th</strong>e ballast.<br />
- Motor loads <strong>ac</strong>count for <strong>th</strong>e largest portion <strong>of</strong> <strong>th</strong>e total electrical load. This is an<br />
indication <strong>th</strong>at <strong>th</strong>ere are energy conservation opportunities in <strong>th</strong>e system.<br />
- The electrical power f<strong>ac</strong>tor <strong>of</strong> five plants ranged between 83.75% and 99.5%. In one<br />
plant, however, <strong>th</strong>e mon<strong>th</strong>ly metered power f<strong>ac</strong>tor <strong>of</strong> <strong>th</strong>e plant’s electrical system<br />
averages at a very low 72.58%. As a result <strong>of</strong> <strong>th</strong>is very low power f<strong>ac</strong>tor, a power f<strong>ac</strong>tor<br />
adjustment or penalty is added to <strong>th</strong>e electricity bill.<br />
- To ensure a reliable supply <strong>of</strong> electricity, at least two paper mills are seriously considering<br />
to install 12 to 20 MW cogeneration systems. Assuming <strong>th</strong>at 50% <strong>of</strong> <strong>th</strong>e industry will<br />
install cogeneration systems to be self-sufficient in its <strong>th</strong>ermal and electrical requirements,<br />
a considerable amount <strong>of</strong> savings in annual fuel consumption can be realized.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 113<br />
- Air intake in compressed air systems is <strong>of</strong>ten from <strong>th</strong>e same enclosed area/surroundings<br />
where <strong>th</strong>e compressors are located.<br />
- Pumps and refiners utilized by <strong>th</strong>e paper industry are quite inefficient. Pumps normally<br />
consume 25 to 35% <strong>of</strong> electrical energy, while refiners use up 15 to 25%. The low<br />
efficiency <strong>of</strong> <strong>th</strong>ese m<strong>ac</strong>hines may be attributed to design cap<strong>ac</strong>ity and <strong>ac</strong>tual process<br />
requirements. O<strong>th</strong>er f<strong>ac</strong>tors which significantly influence power consumption and<br />
refining results are <strong>th</strong>e types <strong>of</strong> refiner, plate pattern, and speed.<br />
- Paper drying consumes <strong>th</strong>e biggest share <strong>of</strong> <strong>th</strong>e process steam. An increase <strong>of</strong> about 2 to<br />
35% <strong>of</strong> paper web dryness after press may be <strong>ac</strong>hieved if a typical press part is improved.<br />
This alone would reduce steam consumption <strong>of</strong> paper drying by 8 to 12%. It could also<br />
improve <strong>th</strong>e m<strong>ac</strong>hine’s efficiency.<br />
6.3.5.2 Energy conservation program<br />
Majority <strong>of</strong> <strong>th</strong>e companies in <strong>th</strong>e industry do not have formal energy conservation committee at<br />
present. Some used to be very <strong>ac</strong>tive in energy conservation earlier and have, in <strong>th</strong>e past,<br />
implemented a number <strong>of</strong> energy conservation measures or are still carrying out energy<br />
conservation <strong>ac</strong>tivities but in a much less aggressive manner.<br />
6.3.6 Status <strong>of</strong> application <strong>of</strong> new technologies<br />
In spite <strong>th</strong>e opportunities for energy conservation in <strong>th</strong>e industry, <strong>th</strong>ere are barriers to <strong>th</strong>eir<br />
effective implementation. These include technical, financial, institutional and o<strong>th</strong>er related issues as<br />
perceived by <strong>th</strong>e industry.<br />
The technical barriers in <strong>th</strong>e implementation <strong>of</strong> energy conservation technologies are mostly due to<br />
existing plant layout, support f<strong>ac</strong>ilities and services <strong>of</strong>fered by suppliers. For waste fuel utilization<br />
and coal conversion, problems on pollution, safety, and effects on quality <strong>of</strong> products were noted.<br />
These barriers include <strong>th</strong>e l<strong>ac</strong>k <strong>of</strong> information on reliable suppliers and services <strong>of</strong>fered, l<strong>ac</strong>k <strong>of</strong><br />
expertise regarding operation, maintenance and servicing <strong>of</strong> equipment/system, and o<strong>th</strong>er<br />
operation-related problems.<br />
The financial/economic viability <strong>of</strong> energy conservation technologies is a major concern <strong>of</strong> every<br />
industry, and <strong>th</strong>e most common financial barriers include <strong>th</strong>e unavailability <strong>of</strong> funds for energy<br />
conservation projects and <strong>th</strong>e l<strong>ac</strong>k <strong>of</strong> skill, bo<strong>th</strong> <strong>of</strong> plant personnel and financial institution<br />
personnel, in <strong>th</strong>e p<strong>ac</strong>kaging and evaluation <strong>of</strong> energy conservation projects.<br />
There is also a need to enhance <strong>th</strong>e existing institutional framework <strong>th</strong>at promotes and encourages<br />
energy conservation. A more aggressive information/dissemination campaign should be<br />
emphasized to encourage <strong>th</strong>e industry to pr<strong>ac</strong>tice energy conservation.
114 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
6.3.7 Concluding remarks<br />
The pulp and paper industry in <strong>th</strong>e Philippines has been described as small, outmoded, and highly<br />
protected. It is generally inefficient and internationally non-competitive, wi<strong>th</strong> bleak long-term<br />
prospects. Most <strong>of</strong> <strong>th</strong>e m<strong>ac</strong>hines in <strong>th</strong>e pulp and paper sector are old and repl<strong>ac</strong>eable. It is<br />
believed <strong>th</strong>at 10 reasonably-sized paper m<strong>ac</strong>hines can easily produce 600,000 to 700,000 tons <strong>of</strong><br />
<strong>th</strong>e required one million tons projected for <strong>th</strong>e year 2000. Operating fewer but bigger units will<br />
take advantage <strong>of</strong> economies <strong>of</strong> scale and benefit from modern process technologies.<br />
In <strong>th</strong>e f<strong>ac</strong>e <strong>of</strong> existing conditions, expansion is not recommended for <strong>th</strong>e local industry. The<br />
increasing pressure to install environmental protection f<strong>ac</strong>ilities in all mills and <strong>th</strong>e required<br />
dislocation <strong>of</strong> plants outside <strong>th</strong>e densely populated metropolis likewise demand a major structural<br />
change. Millers are, <strong>th</strong>erefore, encouraged to relocate outside <strong>th</strong>e densely populated metropolis<br />
wi<strong>th</strong> <strong>th</strong>e high cost <strong>of</strong> environmental protection necessitating relocation in areas which are less<br />
populated.<br />
Since <strong>th</strong>e industry has not yet re<strong>ac</strong>hed <strong>th</strong>e ultimate limits <strong>of</strong> resource-use efficiency, reducing waste<br />
generation should be high on <strong>th</strong>e industry’s agenda, not only because <strong>of</strong> concern for <strong>th</strong>e<br />
environment, but for <strong>th</strong>e more fundamental reason <strong>of</strong> improving pr<strong>of</strong>itability. After all, whatever<br />
<strong>th</strong>e industry discharges as waste are essentially <strong>th</strong>e very resources it buys and pays for in <strong>th</strong>e first<br />
pl<strong>ac</strong>e. No<strong>th</strong>ing comes free. Yet in <strong>th</strong>e past, waste reduction never received <strong>th</strong>e priority it deserved.<br />
It is important, <strong>th</strong>erefore, to reflect and analyze why.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 115<br />
6.4 COUNTRY REPORT: SRI LANKA<br />
6.4.1 Introduction<br />
The current gross domestic product <strong>of</strong> Sri Lanka is estimated to be increasing at 6.9%. Manuf<strong>ac</strong>turing,<br />
wholesale and retail trade and agriculture are <strong>th</strong>e most important contributory sectors to <strong>th</strong>e grow<strong>th</strong>.<br />
In 1993, <strong>th</strong>e GDP at current market price was estimated to be Rs. 150.8 billion, wi<strong>th</strong> agriculture,<br />
forestry and fishing contributing 21.2% share <strong>of</strong> <strong>th</strong>e GNP, mining and quarrying 2.5%, manuf<strong>ac</strong>turing<br />
19.4%, wholesale and retail trade 21.8% and construction 7%.<br />
The population <strong>of</strong> Sri Lanka in 1993 has been estimated at 17.62 million. The per capita GNP at<br />
current f<strong>ac</strong>tor cost prices is estimated at US$ 526 in 93, an increase <strong>of</strong> 16.5% over previous year.<br />
Pulp and paper industry in Sri Lanka was introduced in <strong>th</strong>e 1950’s by <strong>th</strong>e state and was managed by<br />
<strong>th</strong>e state until very recently. The m<strong>ac</strong>hinery and <strong>th</strong>e technologies are generally old. Though it has been<br />
realised <strong>th</strong>at improvements in energy efficiency and environmental standards are very desirable, <strong>th</strong>e<br />
l<strong>ac</strong>k <strong>of</strong> finances has impeded <strong>th</strong>is development.<br />
6.4.2 Technological trajectory <strong>of</strong> <strong>th</strong>e Sri Lankan pulp and paper industry<br />
6.4.2.1 Cap<strong>ac</strong>ity, production, raw material and process mix<br />
There are two paper mills in Sri Lanka. The pulp manuf<strong>ac</strong>turing techniques <strong>of</strong> <strong>th</strong>ese mills are soda<br />
pulping and neutral sulfite semi-chemical processes. Bo<strong>th</strong> <strong>th</strong>ese plants are designed to use straw as <strong>th</strong>e<br />
raw material. Figure 6.4.1 shows <strong>th</strong>e pulp production and Figure 6.4.2 shows <strong>th</strong>e raw material mix for<br />
pulp production. The second plant was commissioned in <strong>th</strong>e late seventies <strong>th</strong>us increasing <strong>th</strong>e total<br />
installed cap<strong>ac</strong>ities. However, as sections <strong>of</strong> <strong>th</strong>e older plants become unavailable for production, <strong>th</strong>e<br />
total installed cap<strong>ac</strong>ity gradually decreased. This is reflected in Figure 6.4.1.<br />
The extent <strong>of</strong> production <strong>of</strong> pulp from rice straw gradually decreased due to <strong>th</strong>e environmental effect<br />
<strong>of</strong> discharges from <strong>th</strong>is process. To make up for <strong>th</strong>ese losses, <strong>th</strong>e production from waste paper<br />
increased proportionately. The productivity reported is shown in Table 6.4.1.<br />
Table 6.4.1 Reported productivity in Sri Lankan pulp and paper industry<br />
Year Productivity (ton/employee)<br />
1960 7.7<br />
1980 5.4<br />
1990 6.2<br />
1992 9.2<br />
The shortfall between <strong>th</strong>e demand for pulp and local production were met by gradual increase <strong>of</strong><br />
imported pulp from large pulp manuf<strong>ac</strong>turers, as <strong>th</strong>ese became economically attr<strong>ac</strong>tive.
116 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Pulp Production<br />
14000<br />
12000<br />
10000<br />
8000<br />
6000<br />
4000<br />
2000<br />
0<br />
1970 1980 1990 1992<br />
Year<br />
Installed Cap<strong>ac</strong>ity From Straw & Wood From Waste Paper<br />
Figure 6.4.1 Sri Lanka’s pulp production cap<strong>ac</strong>ity by source (tons)<br />
Raw material<br />
35000<br />
30000<br />
25000<br />
20000<br />
15000<br />
10000<br />
5000<br />
0<br />
1970 1980 1990 1992<br />
Year<br />
Wood Straw<br />
Figure 6.4.2 Raw material mix for pulp production (tons)<br />
6.4.2.2 Role <strong>of</strong> <strong>th</strong>e pulp and paper industry in <strong>th</strong>e national economy<br />
Paper is a direct input to o<strong>th</strong>er economic <strong>ac</strong>tivities like printing and service sectors and remains very<br />
important in Sri Lankan economy al<strong>th</strong>ough its relative importance in terms <strong>of</strong> production is not very<br />
significant. The contribution <strong>of</strong> <strong>th</strong>e pulp and paper industry to <strong>th</strong>e Sri Lankan national economy is
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 117<br />
demonstrated by its high value added and employment and pr<strong>of</strong>itability ratios. The percentage <strong>of</strong><br />
value added to GDP and <strong>th</strong>e value <strong>of</strong> output has been increasing over <strong>th</strong>e years. Table 6.4.2 shows<br />
some key economic indicators <strong>of</strong> <strong>th</strong>e sector.<br />
Table 6.4.2 Economic indicators <strong>of</strong> <strong>th</strong>e pulp and paper industry<br />
Year 1985 1993<br />
Value Added to GDP (Million<br />
Rs.)<br />
200.235 416.347<br />
No. <strong>of</strong> Direct Employees<br />
Sector employment as a ratio <strong>of</strong>:<br />
3953 3167<br />
Industrial Employment 1.26% 0.4%<br />
Total Employment 0.08% 0.06%<br />
Direct employment in <strong>th</strong>e pulp and paper sector declined by about 19% between <strong>th</strong>e years 1985 and<br />
1993. This was caused mainly by <strong>th</strong>e closure <strong>of</strong> <strong>th</strong>e Val<strong>ac</strong>hchenai plant owing to terrorism in <strong>th</strong>e<br />
Eastern part <strong>of</strong> Sri Lanka since 1985.<br />
6.4.3 Evolution <strong>of</strong> energy efficiency in <strong>th</strong>e pulp and paper industry <strong>of</strong> Sri Lanka<br />
Figure 6.4.3 shows <strong>th</strong>e specific energy consumption <strong>of</strong> <strong>th</strong>e two processes. These f<strong>ac</strong>tories have been<br />
operating on varying raw material and technological mixes over <strong>th</strong>e years. Whenever imported pulp or<br />
waste paper was cheaper, <strong>th</strong>e imported component increased substantially. Thus over <strong>th</strong>e years, <strong>th</strong>ese<br />
plants have been operating wi<strong>th</strong> varying degrees <strong>of</strong> integration, giving non-consistent values for<br />
specific energy consumption.<br />
6.4.4 Environmental externalities in <strong>th</strong>e pulp and paper industry <strong>of</strong> Sri Lanka<br />
The paper mill which was commissioned in <strong>th</strong>e 1950's, does not have a chemical recovery plant and<br />
<strong>th</strong>e bl<strong>ac</strong>k liquor was directly discharged into a natural water stream. This has caused a severe<br />
environmental problem in <strong>th</strong>e area. The stream became dead due to oxygen depletion and <strong>th</strong>e<br />
deposition <strong>of</strong> fibrous material along <strong>th</strong>e banks. The lagoon which receives <strong>th</strong>e water stream which was<br />
rich in prawns and o<strong>th</strong>er varieties <strong>of</strong> fish also became dead. This has led to some serious social<br />
problems in <strong>th</strong>e fishing villages <strong>of</strong> <strong>th</strong>e area.
118 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Specific Energy Consumption<br />
0.9<br />
0.8<br />
0.7<br />
0.6<br />
0.5<br />
0.4<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
1980 1990<br />
Year<br />
1992<br />
Soda Pulping Sulfite Process<br />
Figure 6.4.3 Specific energy consumption for soda and sulfite pulping processes<br />
(toe/t <strong>of</strong> pulp)<br />
In <strong>th</strong>e eighties <strong>th</strong>e use <strong>of</strong> straw as raw material was reduced and recycling <strong>of</strong> waste paper was increased<br />
in <strong>th</strong>is f<strong>ac</strong>tory. In <strong>th</strong>e early 90s, pulp production from straw was completely stopped. Since <strong>th</strong>en <strong>th</strong>e<br />
environmental issue <strong>of</strong> discharging effluent into <strong>th</strong>e lagoon has been satisf<strong>ac</strong>torily resolved.<br />
The second plant which was commissioned in <strong>th</strong>e 1970's was equipped wi<strong>th</strong> a chemical recovery<br />
plant. Unfortunately <strong>th</strong>is plant has never been commissioned due to <strong>th</strong>e high silica content in <strong>th</strong>e<br />
bl<strong>ac</strong>k liquor.<br />
Since <strong>th</strong>e inception <strong>of</strong> <strong>th</strong>e plant <strong>th</strong>e effluents from <strong>th</strong>e mill have been discharged into a main river. As<br />
<strong>th</strong>e effluents are discharged wi<strong>th</strong>out chemical recovery, <strong>th</strong>e pollution caused to <strong>th</strong>e river is appreciable.<br />
The users <strong>of</strong> <strong>th</strong>e river water are agitating for remedial <strong>ac</strong>tion.<br />
6.4.5 Potential for energy efficiency improvement and pollution abatement <strong>th</strong>rough<br />
technological changes<br />
The following options may be examined to resolve <strong>th</strong>e high energy cost and <strong>th</strong>e environmental<br />
problems caused:<br />
(a) Change Raw Material<br />
- By changing <strong>th</strong>e raw material from rice straw to bagasse, <strong>th</strong>e silica problem in <strong>th</strong>e bl<strong>ac</strong>k<br />
liquor could be overcome. Wi<strong>th</strong> minor modification to <strong>th</strong>e chemical recovery plant,<br />
chemicals in <strong>th</strong>e effluent could be recovered. Adequate bagasse is available in <strong>th</strong>e locality.
Pr<strong>of</strong>ile <strong>of</strong> <strong>th</strong>e Pulp and Paper Industry in Selected <strong>Asian</strong> Countries 119<br />
- The use <strong>of</strong> wood as raw material for <strong>th</strong>e manuf<strong>ac</strong>ture <strong>of</strong> pulp will have similar advantages as<br />
above. The resources needed for growing <strong>of</strong> trees for <strong>th</strong>is purpose are available.<br />
(b) Change <strong>of</strong> Chemical<br />
By <strong>th</strong>e use <strong>of</strong> potassium hydroxide instead <strong>of</strong> sodium hydroxide for cooking <strong>of</strong> rice straw, <strong>th</strong>e effluent<br />
could be collected and marketed as potassium based fertilizer.<br />
(c) Change <strong>of</strong> Fuel<br />
As <strong>th</strong>e paper f<strong>ac</strong>tories are located in <strong>th</strong>e rice growing and processing areas, adequate quantities <strong>of</strong> rice<br />
husk is available to be used as fuel for <strong>th</strong>e production <strong>of</strong> steam for heat and electricity.
120 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
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Section 5<br />
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Section 6.1<br />
A. References<br />
[1] Alman<strong>ac</strong> <strong>of</strong> China’s Paper Industry, 1993, Edited by China Technical Association <strong>of</strong> Paper<br />
Industry (CTAPI).<br />
[2] Alman<strong>ac</strong> <strong>of</strong> China's Paper Industry 1990, Edited by China Technical Association <strong>of</strong> Paper<br />
Industry (CTAPI).<br />
[3] Alman<strong>ac</strong> <strong>of</strong> China's Paper Industry 1986, Edited by China Technical Association <strong>of</strong> Paper<br />
Industry (CTAPI).<br />
[4] Chen Yonghong, Energy Issues and Counter-measures for <strong>th</strong>e Paper Industry <strong>of</strong> China,<br />
Proceedings <strong>of</strong> <strong>th</strong>e Annual Academic Conference <strong>of</strong> CTAPI, 1985.<br />
[5] Chen Zhongxing, Cogeneration in Pulp and Paper Mills <strong>of</strong> China, COPED core project<br />
1993/1994.<br />
[6] China Energy Statistical Book 1991, China Statistic Press.<br />
[7] Environmental Imp<strong>ac</strong>ts <strong>of</strong> <strong>th</strong>e Technological Transformation Project in Qiqihar Pulp &<br />
Paper Mill, Planning and Designing <strong>Institute</strong> <strong>of</strong> Light Industry, 1993.<br />
[8] Fen Shiao and Chai Yinian, Estimation <strong>of</strong> <strong>th</strong>e Potential <strong>of</strong> Cogeneration (CHP) in China's<br />
Pulp & Paper Industry, Energy <strong>of</strong> China, July, 1993.<br />
[9] Integrated exploitation <strong>of</strong> steamed & boiled wastewater and its pollution protection<br />
technologies, Edited by Zhang Ke et al., China Light Industry Press, 1992.
126 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
[10] Li Jiawan, Current Situation <strong>of</strong> World Paper Industry in 1990s and Its Perspective, World<br />
Pulp & Paper Mills Data Book, 1992.<br />
[11] Statistical Yearbook <strong>of</strong> China, China Statistical Press, 1994.<br />
[12] Studies on Unit Major Products Energy Consumption, Edited by Liu Xueyi, Guanminri<br />
Daily Press, 1989.<br />
[13] Yu Yiji, Speed, Efficiency and Environmental Protection — Some Considerations on<br />
Sustainable Development <strong>of</strong> China's Pulp & Paper Industry, China Pulp & Paper, Dec.,<br />
1994.<br />
[14] Zhang Shuyu and Meng Zhaoli, Final Report on Energy Audit <strong>of</strong> Qiqihar Paper Mill,<br />
Technological Support Project for Industrial Energy Conservation, sponsored by ADB,<br />
1990.<br />
B. Bibliography<br />
Cao Pia<strong>of</strong>ang and Jiang Manxia, General Situations <strong>of</strong> China Paper Industry Pollution<br />
Protection, China Pulp & Paper, No. 5, Oct. 1994.<br />
Huanqinan et al. (eds.), Development Strategy <strong>of</strong> China’s Paper Industry, China Light Industry<br />
Press, 1992.<br />
ITEESA, Evaluation <strong>of</strong> Energy Efficiency in Pulp & Paper Industry in P.R. China, Invited<br />
Report, ITEESA.<br />
Pan Peilei, Call for Efforts to Contribute to Environmental Protection in Pulp & Paper Industry,<br />
China Pulp & Paper, Aug., 1994.<br />
Yan Erpin, Study on Heat Pump Drying <strong>Technology</strong> in Paper M<strong>ac</strong>hine Parts, China Pulp &<br />
Paper, December 1994.<br />
Zhang Houmin, Bio-technology and Pulp & Paper Industry, China Pulp & Paper, Aug. 1994.<br />
Section 6.2<br />
[1] Comprehensive industry document for large pulp & paper industry, CBCP Publication.<br />
[2] Comprehensive industry document for small pulp & paper industry, CBCP Publication.<br />
[3] CPPRI Database.
Bibliography 127<br />
[4] Development Council for Paper Pulp & Allied Products.<br />
[5] Environmental preservation course in pulp & paper industry, Markyd, Sweden.<br />
[6] Evaluation <strong>of</strong> energy efficiency in connection wi<strong>th</strong> technology - Report prepared by<br />
Central Pulp & Paper Research <strong>Institute</strong> (CPRRI) for National Productivity Council, 1985.<br />
[7] Indian Pulp & Paper Technical Association (IPPTA), vol.1, no.4, Dec. 1989.<br />
[8] IPPTA convention issue on energy conservation, 1984.<br />
[9] Paper Asia, July 1993.<br />
[10] Proceedings <strong>of</strong> inter<strong>ac</strong>tion meet on high rate bio-me<strong>th</strong>anation <strong>of</strong> pulp & paper mill waste<br />
(UNDP/GEF project).<br />
[11] Proceedings <strong>of</strong> <strong>th</strong>e inter<strong>ac</strong>tion meet on waste management in <strong>th</strong>e pulp & paper industry<br />
towards sustainable development - Central Pollution Control Board (CPCB).<br />
[12] Report prepared by CPPRI for <strong>th</strong>e 8<strong>th</strong> five year <strong>ac</strong>tion plan.<br />
[13] UNEP report on environmental management in pulp & paper industry.<br />
Section 6.3<br />
Aragon, P.M., “The Philippines: Promising Outlook”, Country Focus.<br />
Hargb<strong>ac</strong>k, H., “Environmental Management Plan: Pulp and Paper Industry”, A Report to <strong>th</strong>e<br />
Development Bank <strong>of</strong> <strong>th</strong>e Philippines, June 25, 1992.<br />
Dalusong II, A.R., “Energy Development in <strong>th</strong>e Light <strong>of</strong> Current Environmental Issues: The<br />
Philippine Case”, Energy Policy Implications <strong>of</strong> <strong>th</strong>e Climatic Effects <strong>of</strong> Fossil Fuel Use in <strong>th</strong>e<br />
Asia-P<strong>ac</strong>ific Region, Bangkok, Thailand. November, 1991.<br />
Nyati, K.P., “Prospect, Barriers and Strategies - Cleaner Industrial Production in Developing<br />
Countries”, pp. 10-14, Asia P<strong>ac</strong>ific Tech. Monitor, Nov-Dec 1994, ESCAP APCTT, New Delhi,<br />
India.<br />
Oy, J.P., “Industrial Restructuring Studies: Pulp and Paper”, Development Bank <strong>of</strong> <strong>th</strong>e<br />
Philippines, 1992.
128 <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e Pulp and Paper Industry<br />
Schafer, A. et al., “Inventory <strong>of</strong> Greenhouse Gas Mitigation Measures - Examples from <strong>th</strong>e<br />
IIASA <strong>Technology</strong> Data Bank”.
The <strong>Asian</strong> <strong>Institute</strong> <strong>of</strong> <strong>Technology</strong> (AIT) is an autonomous international <strong>ac</strong>ademic institution<br />
located in Bangkok, Thailand. It’s main mission is <strong>th</strong>e promotion <strong>of</strong> technological changes<br />
and <strong>th</strong>eir management for sustainable development in <strong>th</strong>e Asia-P<strong>ac</strong>ific region <strong>th</strong>rough highlevel<br />
education, research and outre<strong>ac</strong>h <strong>ac</strong>tivities which integrate technology, planning and<br />
management.<br />
AIT carried out <strong>th</strong>is <strong>Asian</strong> Regional Research Programme in Energy, Environment and Climate<br />
(ARRPEEC), wi<strong>th</strong> <strong>th</strong>e support <strong>of</strong> <strong>th</strong>e Swedish International Development Cooperation Agency (Sida).<br />
One <strong>of</strong> <strong>th</strong>e projects under <strong>th</strong>is program concerns <strong>th</strong>e Development <strong>of</strong> Energy Efficient<br />
and Environmentally Sound Industrial Technologies in Asia.<br />
The objective <strong>of</strong> <strong>th</strong>is specific project is to enhance <strong>th</strong>e synergy among selected developing<br />
countries in <strong>th</strong>eir efforts to adopt and propagate energy efficient and environmentally sound<br />
technologies. The industrial sub-sectors identified for in-dep<strong>th</strong> analysis are iron & steel,<br />
cement, and pulp & paper. The project involves <strong>ac</strong>tive participation <strong>of</strong> experts from<br />
collaborating institutes from four <strong>Asian</strong> countries, namely China, India, <strong>th</strong>e Philippines, and<br />
Sri Lanka.<br />
The technological trajectories, energy efficiency and environmental externalities <strong>of</strong> <strong>th</strong>e pulp<br />
and paper industry in <strong>th</strong>e four <strong>Asian</strong> countries are presented in <strong>th</strong>is document (Volume III).<br />
O<strong>th</strong>er related publications based on <strong>th</strong>is research finding include:<br />
Volume I <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e<br />
Cement Industry<br />
Volume II <strong>Technology</strong>, Energy Efficiency and Environmental Externalities in <strong>th</strong>e<br />
Iron & Steel Industry<br />
Volume IV Regulatory Measures and Technological Changes in <strong>th</strong>e Cement, Iron<br />
& Steel, and Pulp & Paper Industries<br />
An assessment <strong>of</strong> <strong>th</strong>e implementation <strong>of</strong> energy efficient and environmentally sound<br />
industrial technologies among <strong>th</strong>e selected countries is presented in a separate “Cross-<br />
Country Comparison” Report.<br />
ASIAN INSTITUTE<br />
OF TEC HN OLOGY<br />
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