O&M of Mid Sized Power Plants: The Modern Trends - By ... - Infraline

Operation and Maintenance
of Midsize Power Plants
The Modern Trends
14th DEC2006
V. B. Kabra
Thermax Babcock & Wilcox- R&D

Modern Trends in Energy Systems
Efficiency / Reliability
Improvement
Energy
Systems
Redesign with
alternate operating inputs
Renewable Energy

Efficiency / Reliability Improvement
Energy Audit
Efficiency/
Reliability
Improvement
Efficiency
Controls
Operation &
Maintenance

Energy Audit
Revisit the operation and maintenance
philosophy with breakdown structure
• Boiler, turbine, condenser, Heating and cooling systems of plant,
Electrical systems, drives, fuel handling systems etc.
Compare with a world class energy efficient units
of similar nature
• Power, steel, refineries, heavy chemicals etc.
Apply modern tools to identify the waste areas
• Over design
• Wrong selection
• Improper operational practices
Apply modern techniques of maintenance: TPM,
RLA, Diagnostic

Improving efficiency of Boiler Plant
Overall efficiency of GCV - Direct/Indirect
Improve efficiency
• Reduce stack temp. - How low ? -
Sulfur corrosion/Low LMTD for ECO
•Reduce Excess air
•Reduce radiation loss
•Reduce Unburnt carbon loss
•Reduce Blow down loss
•Improve efficiency of feed pumps and fans-VFD
Min.Recirculation control ,Optimum Pressures
•Combustion control
•Changing firing system -FBC
•Minimizes water & steam side depositions
Fuel additives /Combustion systems/deposit monitoring system

Energy saving potential
Energy saving potential in major auxiliaries
Area Potential %
Fans 10 - 50
Feed W ater pumps 5 - 25
Cooling W ater Pumps 5 – 25
Cooling Tower 10 – 15
Enhancing Cogeneration 20 - 25
• National Benchmark : 6.5% ( Coal Fired)
NTPC Western Region
• International Benchmark : 3.66% ( Coal Fired)
Shanghai Shidonhkou Power Plant
(2 x 600MW) for year 2000

Efficiency improvement
Auxiliary power consumption- Utility
Coal based Stations
With cooling
tower
Without cooling
tower
25 – 100 Mwe 10-11% 9-10%
200 MWe series
500 MW with steam
driven feed pumps
9.5 % 8.5 %
8.0 % 7.5 %
Gas and Naphtha based stations
Combined cycle
plants
3.0%

Efficiency improvement
Install VFD/ Variable Fluid Coupling for Fan with
feedback control
• Quantity of air delivered - 30 TPH
(7.29 m 3 / sec)
• Pressure developed - 510 mmWC
• Power Consumption - 73 kW
• Operating efficiency of fan - 55.53%
• IGV control results in drop in operating efficiency
Description Before After
Air Flow (TPH) 32 32
Pressure developed (mmWC) 520 525
Power Consumption (kW) 73 58
Control
IGV – 46%
open
VFD
Efficiency 55.53 % 76.28 %

Efficiency improvement
Enhancing Cogeneration
• Process steam requirements
- Met by steam through PRDS
• Any Energy Loss
- Big opportunity lost if the steam flow at lower pressure
is substantial

Opportunity Loss
45bar, 450deg cel,
797 kCal/kg
Auxiliary Steam header
21bar, 310 deg cel
45 - 50 TPH
Any throttling process - opportunity lost

Opportunity available
45 bar, 450deg cel,
797 kCal/kg
Opportunity
: 1.1 MW
Auxiliary Steam header
21bar, 280 deg cel
708 kcal/kg
Auxiliary steam- same pressure,
superheated

Install steam drives for pumps
Users for low temperature steam
• Fuel areas
• Oil burner atomizing
• Gland steam
• Soot blowing
• Annual saving
• Investment
• Payback period
-Rs 59.00 Lakhs
-Rs. 125 Lakhs
-26 months

Steam Usage
Effective Condensate Removal
• Inefficient condensate removal in equipments will retard heat
transfer process in equipments causing
(a) Drop in production time.
(b) Fall on quality of output.
Methods of trap monitoring tried and discarded
• Spitting on trap body-most crude method
• Industrial crayon colours - Color change with temp.difference
• Industrial stethoscope -Bits due to velocity change
• Surface temp measurement -Not very useful Unless subcooled
• Ultrasonic measurement- Gaining popularity -Require Skill
• Conductivity sensor -Best method but requires investment
Condensate Recovery

Enhancing efficiency
Deaerator
• Operate at optimum temperature
Feed water temperature 105 deg cel
Potential to increase temperature by 10 deg cel
• Additional steam consumption of 0.9 TPH
Additional power generation
• 117 kWh/ ton of steam
Monitor furnace gas temperature
Optimise soot blowing operations
Optimise for Dew Point corrosion

Operator’s interface
Monitoring systems will ensure
energy efficiency
Link to operator’s performance
Shift-wise data monitoring

Controls
Modern DCS monitoring system
Smart intelligent efficiency monitoring systems
Computational Flow Dynamics analysis for
improving the flow patterns
Remote performance monitoring system

Life Extension Program
A well organised Life Extension Program should
consist of the following phases of work
1. Evaluation and Planning
2. Outage- Inspection, Testings, Condition Assessment
3. Post outage Testing and Studies
4. Reports, Recommendations, Implementations of
Recommendations

Why Life Extension?

Potential causes for Premature
failures
Corrosion
Erosion
Overheating
Over stressing
Hydrogen Embrittlement
Wrongly applied material
Cycling Fatigue
Corrosion Fatigue

Internal Oxide Scale in SH Tube
Scale forms on the
steam side of
superheater tubes
in service.
The thickness of
the scale formed is
a function of time in
service and tube
metal temperature.

Inspection Techniques
Replication
• Mechanical Polishing
• Electro polishing
Hone and Glow
NOTIS
(Non-destructive Oxide Thickness Inspection System)
FHyNES
(Furnace Hydrogen damage Non-destructive Examination Service)
MANTIS
(Modular Automated Non-destructive Thickness Inspection System)

Nondestructive
Oscilloscope
Oxide
Thickness
Inspection
System
Oxide
Thickness
Oxide Scale
Wall
Thickness
Special UT
Transducer
Tube OD

FHyNES ®
Transducer
Furnace Side
of Tubes
Hydrogen
Damage
Amplitude %
FHyNES Scope
100
80
60
40
20
0
2 4 6 8 10
Signal from
Undamaged
Tube

Redesign with Alternate Operating
Inputs
Review cost of fuel input
Review existing operating parameters
Explore possibility of low cost fuels
Review availability of waste fuels in the
area
Evaluation for conversion to multifuel
firing capabilities through experts/ OEM

Steam Cost
Cost comparison
Boiler Fuel GCV Fuel cost Efficiency Heat input Steam cost
Kcal/kg Rs/kg % MKcal/hr Rs/ton
Oil/gas LDO 10200 19.00 87 32.59 1445.30
FO 10000 17.00 86 32.97 1334.36
LSHS 10500 16.00 87 32.59 1182.32
NG 12000 9.00 85 33.35 595.62
NAPHA 9500 22.00 87 32.59 1796.81
TG COAL 4000 2.20 77 36.82 482.16
LIGNITE 3600 1.50 75 37.80 375.02
BAGASSE 2200 0.40 69 41.09 177.87
RICE HUSK 3000 1.00 75 37.80 300.01
FBC COAL 4000 2.20 84 33.75 441.98
LIGNITE 3600 1.50 80 35.44 351.58
RICE HUSK 3000 1.00 81 35.00 277.79
OTHER BIOMAS 3200 0.75 80 35.44 197.76
Coal+petcoke 6520 3.00 81 35.00 383.45
CFB COAL 4000 2.20 87 32.59 426.74
PETCOKE 8200 3.20 88 32.22 299.35
Boiler : 42 TPH 45 Kg/cm2 420 deg.cel.
Heat output : 28.3513 Mkcal/hr

TBW /Thermax Energy Solutions
CFBC boilers - Multifuel firing/ Biomass
AFBC boilers - Multifuel firing/ Biomass
Grate fired - Multifuel firing/ Biomass/ Bagasse
HRSGs -Fired/ Unfired/ Fresh air fired
Oil & Gas fired radiant boilers/ FM boiler -
FO, LDO, LSHS, Naphtha, NG, COG, BFG, LNG
Low NOx Burners
Renovation & Modernisations
• Plant improvement projects
• RLA studies
• Build to Print/ Spares

TBW /Thermax Energy Solutions
Waste heat Recovery systems
• Process Integrated Boilers
• Exhaust Gas Boilers
• Waste Heat Boilers
Fired Systems
• Solid fuel fired
• Fired Heaters
• Waste fired Boilers

Petcoke Firing Technology
PC FRING: Low VM restrict use, Up to 10 % blend with high
VM coal. Higher percentage firing would also call for FGD
system for SO2 Scrubbing.
CFBC: Most suited technology, Firing up to 100% lower
emissions of Sox (

TBW/B&W EXPERIENCE IN
PETCOKE FIRING
Results from the R&D tests were further
demonstrated by commissioning 2 X 80 TPH
steam generator at Shree Cement firing Petcoke
70 to 80% and units are in continuos operation
since DEC2003.
Based on R&D Trials of co firing Petcoke with
Rice Husk up to 50 %, the data is co related for
design of 50 TPH unit under Installation In UP
for Paper mill captive power plant
Further R&D testing is proposed for Co Firing
with other Biomass/ Lignite.

TBW/B&W Experience in Petcoke
Firing
CFBC
R&D trials were carried out by B&W at Alliance
research center, USA for firing 100% Petcoke in
IR-CFB. Results from the test were correlated with
the boiler design criteria and used to design the
SIU (southern Illinois university) project in USA
for firing 100% Petcoke.
Thai petroleum (Thailand) CFB boiler has been
burning Petcoke & coal since 1998.
TBW offering CFBC boilers for Multifuel firing
upto 300 TPH

Shree Cement
AFBC performance
AVERAGE PARAMETERS DURING THE
PERFORMANCE GURENTEE TEST
Parameter Test parameters Predicted
Boiler load, TPH 75.14 * 80
Steam Pressure, Kg/cm2 (g) 65 65
Steam temperature, °C 485* 495+/-5
Coal flow, Kg/hr 2213.28 ---
Petcoke flow, Kg/hr 5308.88 ---
Petcoke % in fuel mixture, 70.58 70
Coal % in fuel mixture 29.40 30
Sorbent flow, Kg/hr 3150.00 3500
SOx in flue gas,PPM 981.00 1100
O2 in flue gas % 4.40 4.0
Relative Humidity, % 21.00 60
Gas Temp. APH out °C 140.00 140
Efficiency % 83.08** 82

Renewable Energy
Agriculture Based economy get edge
Biomass Power generation Potential - 16000MW
Power potential from Baggasse - 3500MW
===============
Total 19500MW

Categorization of Biomass fuels
Biomass Fuels
Low fouling
fuels
Medium fouling
fuels
Highly fouling
fuels
Baggasse
Rice husk
Juli flora
Palm shells,
Palm kernels
Chili Stalk
Saw dust
De Oiled
Bran(DOB)
Shells- Coconut,
Ground nut
Sunflower Stalk
Rice Straw
Mustard
Stalk.Wheat
straw
Cotton stalk
Empty fruit
Bunch (EFB)

Technologies for Biomass power
generation
Grate firing
Combustion- Direct
Firing Technologies
Fluidised-bed
combustion
Gasification
Biomass
Burner
Anaerobic
digestion
Bio-diesel
Ethanol
Travelling
Pin hole
Vibrating
Conventional
Hopper bottom

Biomass Power - Andhra Sugar
TRAVAGRATE BOILER
• Capacity- 40 tph, 42 KG Cm2g, 440 Deg C
• Fuel : Bagasse and Rice Husk
• Operational since 1995
UNIQUE BENEFITS
• Continuous automatic ash removal system avoids pressure
dip while removing ash
• Efficiently burns fuels like Rice Husk, Bagasse, Wood chips,
Coffee husk etc.
• Catenary design eliminates external chain tightening
mechanism
• Short section grate bars ensures low maintenance
• Grate curvature ensures air sealing
• Easy grate removal
• Hardened Grate support for high temperature applications
• Over fire air system for suspension firing for better
combustion efficiency
• Drum coil attemperator for better steam temperature control

Biomass Power - JOCIL
OPEN HOPPER BOTTOM AFBC BOILER
• Capacity - 30 tph, 66kg cm2g, 485 Deg C,r 6MW
• Design - Open Hopper Bottom Design
• Fuels- Rice Husk, Cotton & Chilly Stalk, Juliflora etc.
• Operational since February’2001.
FEATURES
• Open Hopper Bottom - Babcock & Wilcox Unique Design instead
of conventional bed plate design.
• India’s First Multifuel biomass fired AFBC boiler designed to
handle high alkali fuels.
• Easy control of bed chemistry ensures high availability and
continues power generation
• Easy removal of agglomerates,large amount of stones and mud
ensure trouble free operation round the year
• Separate bunkers & feeders for storing and feeding variety of
fuels to meet any interruption in fuel availability.
• High fuel flexibility ensures cost effectiveness in power
generation.
• Staggered air supply arrangement ensures complete combustion
and high thermal efficiency.

IR-CFBC -The
modern Trend in
Multifuel firing

Internal Recirculation - Circulating
Fluidized Bed Boilers
A simplified approach
to improved flexibility
and reliability
Design Features
• High combustion
efficiency
• Compact, economical
design
• Higher reliability and
availability
• Lower maintenance costs
• Reduced erosion
• Fuel flexibility
• Low emissions

Why Build a CFB Boiler to Generate
Steam and Electric Power
CFB is a Fuel Flexible Technology
• Accepts wide range of fuels
–Volatile matter - 4 - 40%
–Ash - 0 - 60%
–Heating value- > 1500 Kcal/kg (2700 BTU/lb)
–Moisture - < 55%
• Use of lower rank fuels reduces fuel costs
• Fuel flexibility - minimizes fuel supply uncertainties
• Ability to burn low cost and waste fuels

Internal Recirculation - Circulating
Fluidized Bed Boilers

IR-CFB Boilers
Furnace density profile

IR-CFB Boiler Solids Flow
A. Fuel and sorbent solids
entering the furnace
B. Upward solids flow
C. Solids reflected by roof
D. In-furnace U-Beam
recycle
E. External U-Beam recycle
F. Multicyclone recycle
G. Solids not captured by
multicyclone
H. Bed drain

IR-CFB Solids Collection Schematics

IR-CFB Boilers
IR-CFB Primary Particle
Collection System
IR-CFB Particle
Transfer Hopper

U-Beam separators
1
4
1. Sidewall
membrane panel
2. U-beam - SS309H/
SS310H/RA253MA
3. Seal baffle
4. Refractory
Flue
Gas
&
Solid
Flow
3
Flue
Gas
2

U-Beams

Multicyclone Secondary Collector
Individual Gas
Outlet Hoods
• Proven modular design
• Predictable high
performance
• Low maintenance
- Easy access
- High hardness cyclone
tubes
- No refractory
Access for
Inspection
High Hardness
Collection
Components

Kanoria Chemicals & Ind. Ltd
• One CFB; installed
in 1996
• Sub-bituminous
waste coal (45%
ash)
• 231,400 lb/hr (105
TPH) steam flow
• 938 psig (65 barg) /
938°F (503°C)

Overall Grade Separation Efficiency
Comparison
IR-CFB Two Stage Solids Collection System vs
Competitors Cyclone Based CFB System
100
Efficiency, %
90
80
70
60
U-Beam and
MDC-Based
CFB
Cyclone
-Based
CFB
50
40
0 20 40 60 80 100 120
Particle Size, Micron

The B&W IR-CFB Two-Staged Solids
Separation System
Benefits
• High overall solid collection efficiency ~ More than
99.7%
• Precise furnace temperature control ~ By controlling solid
recycle rate from the secondary collector
• Extended turndown ratio without use of auxiliary fuel
(oil/gas) ~ 100% to 20% MCR
• Low auxiliary power requirements compared to
competitor cyclone-based CFB technologies ~ 50-100 mm
w.c.

IR-CFB Furnace Predicted
Temperature Profiles

Kyoto Protocol
Opportunities in INDIA
Power Sector (51%)
• IGCC Power : Potential 10,000 MW ~5Million mt CO 2 pa
Transport Sector (16%)
Industrial Sector
• Steel (10%)
• Cement (4%)
• Chemicals (4%)
• CO 2 Potential >5Million mt CO 2 pa
Renewable Sector ( wind , solar, bagasse, minihydro)
• Potential 35,000 MW: ~60 Million mt CO 2 pa

Renewable Fuel
Utilisation

Fuel Characteristics
Highly variable characteristics- No
generalization
High Volatile Matter - More combustion in free
board
High Moisture- Fuel Handling
Less Ash
High Alkaline content of ash
Low Steam to Fuel weight ratio (Low Specific
heat content

Firing Technologies
Grate firing
• Travelling
• Pin hole
• Vibrating
Fluidised bed combustion
• Conventional
• Hopper bottom
Burner

Technological solutions
Tailor made Combustor design
• TG,CCZ ,Hopper Bottom design
• FEGT, ( < 810 °C )
• Combustion air control system
• Fuel flexibility
Co- Combustion, Right mix of fuel
Additives / Cleaning of heating surfaces
Furnace & Convection Banks Design

Facts about Biomass as fuel
The limited furnace volume and high furnace exit
gas temperatures of most biomass boilers promote
slagging or deposits from those biofuels that
contain significant amounts of potassium or
sodium, sulfur, chlorine and silica.

Hopper bottom design
Unique design of B&W (Developed for effluent
/MDF firing ) which can handle the difficult ,
agglomerating fuels.
Allowing uniform draining of agglomerate /
clinkers through hopper bottom.
Ease on multiple fuel firing through over bed .

Biomass Energy

Thank You!