(BAT) Reference Document for the Production of Chlor-alkali ...
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(BAT) Reference Document for the Production of Chlor-alkali ...

(BAT) Reference Document for the Production of Chlor-alkali ... (BAT) Reference Document for the Production of Chlor-alkali ...

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Chapter 3 INPUTS Consumption, per tonne of chlorine produced Mercury Amalgam Diaphragm Membrane Comments Sulphate 0.12 – 10 kg 0.3 – 0.7 kg (vacuum salt) 15 kg (rock salt) Depends on the purity of the salt Metals Cd, Cr, Cu, Fe, Ni, Pb, Zn, etc. < 0.01 – Depends on the purity of the salt Mercury 2.84 g 0.01 – 0.65 g NA NA western Europe 1998 Asbestos NA Q 30 mg/l NA No specific data available, only if asbestos diaphragms are used To waste Waste generation, per tonne of annual chlorine capacity Brine filtration sludges 20 – 1700 g 120 – 775 g (vacuum salt) 3.7 – 45 kg ~ 30 kg (rock salt) Depends on the purity of the salt Brine softening sludges NA NA 200 – 560 g 600 g Mercury 0 – 130 g 0 – 84 g NA NA western Europe 1998 Asbestos NA 0 – 0.38 kg 0.09 – 0.2 kg NA Depends on lifetime of diaphragms; only if asbestos diaphragms are used Products, per tonne of chlorine produced Membrane Amalgam Diaphragm Comments Sodium hydroxide 1128 kg NaOH (100%); NaCl feedstock Potassium hydroxide 1577 kg KOH (100%); KCl feedstock Hydrogen 28 kg NB: NA = not applicable. These figures are from different available sources and refer to chlor-alkali plants in EU- 27 and EFTA countries Europe using a brine recirculation process. The table does not claim to be complete. Chlorine liquefaction is not included, nor are emissions from cooling systems. {The quantities of produced products per tonne of chlorine produced can be found in Chapters 1 and 2. They should not be mentioned here because they are neither emissions nor consumptions.} WORKING DRAFT IN PROGRESS 66 December 2011 TB/EIPPCB/CAK_Draft_1

3.3 Consumption levels of all cell plants Inputs in the production line 3.3.1 Sodium chloride/potassium chloride Chapter 3 Different types of salt are used to produce the brine for electrolysis (see Section 2.5.1) These types are vacuum-crystallised salt from solution-mined brine, rock salt and solar salt. The stoichiometric salt consumption is 1.65 1.66 tonnes per tonne of chlorine produced. In reality, more salt is consumed because it partly leaves the process via the brine purge which is used to control the levels of impurities in the brine In fact, 1.75 tonnes per tonne of chlorine produced is closer to reality because of impurities control of the brine by purge. Reported consumption levels for plants with brine recirculation are summarised in Table 3.2. Table 3.2: Salt consumption in chlor-alkali plants with brine recirculation in EU-27 and EFTA countries in 2008/2009 Salt consumption in kg per tonne of chlorine produced 10th 25th Salt Minimum percentile percentile Median 75th 90th percentile percentile Maximum NaCl ( 1 ) 1650 1661 1690 1711 1788 2036 2339 KCl ( 2 ) 2098 ND 2100 2117 2145 ND 2200 ( 1 ) 57 data from 54 plants. Three of these plants provided separate data for different electrolysis units. ( 2 ) 8 data from 8 plants. NB: ND = not enough data. Source: [ 57, EIPPCB 2011 ] Another particular case which can occur concerns Diaphragm plants sometimes which prefer to sell the salt from caustic evaporators and buy new feedstock for economic reasons. In plants which operate with waste brine using a once-through brine process, the consumption of salt is about 3 times twice as much as in plants using a brine recirculation process. Reported consumption levels range from 3.1 – 3.8 tonnes of salt per tonne of chlorine produced compared to a median of 1.7 t/t in the case of plants using a brine recirculation system [ 57, EIPPCB 2011 ]. Therefore, 1.4 – 2.1 tonnes of salt per tonne of chlorine produced are wasted which is equivalent to 45 – 55 % of the total salt consumption., i.e. about 5 tonnes of salt per tonne of chlorine produced. Chlor-alkali plants using a waste brine process are located close to big underground salt deposits and which can be found in Spain, Italy, Portugal and the United Kingdom. {This information was moved to Section 2.5.4.} In plants using KCl, the amount of salt needed is a bit higher more than for plants using NaCl feedstock, due to the higher molecular weight of KCl (stoichiometric salt consumption of 2.10 tonnes per tonne of chlorine produced). Consumption in this case is approximately about 2.1 – 2.2 tonnes of salt/ per tonne of chlorine produced (Table 3.2). Plants using KCl do not use the waste brine process. WORKING DRAFT IN PROGRESS 3.3.2 Water For the production of the required demineralised water, several water sources can be used such as groundwater, river water and drinking water. The techniques used to produce demineralised water include ion-exchange, membrane filtration and evaporation [ 3, Euro Chlor 2011 ]. Water is used in mainly added to the process for [ 3, Euro Chlor 2011 ]: purges TB/EIPPCB/CAK_Draft_1 December 2011 67

Chapter 3<br />

INPUTS Consumption, per tonne <strong>of</strong> chlorine produced<br />

Mercury<br />

Amalgam<br />

Diaphragm Membrane Comments<br />

Sulphate<br />

0.12 – 10 kg 0.3 – 0.7 kg (vacuum salt)<br />

15 kg (rock salt)<br />

Depends on <strong>the</strong> purity <strong>of</strong> <strong>the</strong> salt<br />

Metals Cd, Cr, Cu, Fe, Ni, Pb, Zn, etc.<br />

< 0.01 –<br />

Depends on <strong>the</strong> purity <strong>of</strong> <strong>the</strong> salt<br />

Mercury<br />

2.84 g<br />

0.01 – 0.65 g<br />

NA NA western Europe 1998<br />

Asbestos NA Q 30 mg/l NA<br />

No specific data available, only<br />

if asbestos diaphragms are used<br />

To waste Waste generation, per tonne <strong>of</strong> annual chlorine capacity<br />

Brine<br />

filtration<br />

sludges<br />

20 – 1700 g 120 – 775 g (vacuum salt)<br />

3.7 – 45 kg ~ 30 kg (rock salt)<br />

Depends on <strong>the</strong> purity <strong>of</strong> <strong>the</strong> salt<br />

Brine<br />

s<strong>of</strong>tening<br />

sludges<br />

NA NA<br />

200 – 560 g<br />

600 g<br />

Mercury<br />

0 – 130 g<br />

0 – 84 g<br />

NA NA western Europe 1998<br />

Asbestos NA<br />

0 – 0.38 kg<br />

0.09 – 0.2 kg<br />

NA<br />

Depends on lifetime <strong>of</strong><br />

diaphragms; only if asbestos<br />

diaphragms are used<br />

Products, per tonne <strong>of</strong> chlorine produced<br />

Membrane Amalgam Diaphragm Comments<br />

Sodium<br />

hydroxide<br />

1128 kg NaOH (100%); NaCl feedstock<br />

Potassium<br />

hydroxide<br />

1577 kg KOH (100%); KCl feedstock<br />

Hydrogen 28 kg<br />

NB: NA = not applicable. These figures are from different available sources and refer to chlor-<strong>alkali</strong> plants in EU-<br />

27 and EFTA countries Europe using a brine recirculation process. The table does not claim to be complete.<br />

<strong>Chlor</strong>ine liquefaction is not included, nor are emissions from cooling systems.<br />

{The quantities <strong>of</strong> produced products per tonne <strong>of</strong> chlorine produced can be found in<br />

Chapters 1 and 2. They should not be mentioned here because <strong>the</strong>y are nei<strong>the</strong>r emissions nor<br />

consumptions.}<br />

WORKING DRAFT IN PROGRESS<br />

66 December 2011 TB/EIPPCB/CAK_Draft_1

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