Coal technologies

1. Dr. V. K. SETHI
Prof. & Head
RGPV
Bhopal
CLEAN COAL TECHNOLOGIES FOR
SUSTAINABLE POWER DEVELOPMENT

2. PRIORITIES ON ENERGY GENERATION SECTOR:
 Increased use of Advanced Fossil Fuel Technology.
 Promote CCT in countries where coal is main stay
fuel for Power Generation.
 Reduce Atmospheric Pollution from Energy
Generating Systems.
 Enhance productivity through Advanced Fossil Fuel
Technology.
WORLD SUMMIT ON SUSTAINABLE DEVELOPMENT

3. POWER SCENARIO IN INDIA
Installed capacity in utilities (March 31, 2002)
 Thermal 73,274 mw
 Hydro 25,574 mw
 Nuclear 2,860 mw
 Wind 1,427 mw
 Total 1,03,135 mw
 Total energy generation - 383 billion kwh
 Per Capita Energy Consumption -400 kwh

4. DEMAND PROJECTION
YEAR 2012 CAPACITY ADDITION BY SECTORS
 Central 46,500 MW
 State & IPP 41,800 MW
 NCES 10,700 MW
 Nuclear 6,400 MW
 Total 105,400 MW
YEAR 2020 MIX OF GENERATION
 Thermal 326,000MW
 Renewable & Hydro 104,000 MW
 Nuclear 20,000 MW
 Total 450,000 MW

5. CLEAN COAL TECHNOLOGIES
 Mining Management & Practices
(Reduction of Extraneous
material)
 Coal Preparation Process after mining to improve
inherent & Extraneous material
(washing & beneficiation)
 Conversion Technologies Supercritical, PFBC and IGCC
 Post combustion cleaning Particulate and gaseous
pollutants removal
(Environmental requirement)

6. VISION 2020
PROGRAM
Post combustion Clean-up-
Desulfurization
(FGC systems) Supercritical
In-combustion Clean-up
Fluidized bed
combustion (CFBC,
PFBC, AFBC)
Gasification using +
fluidized bed, moving bed
or Entrained bed Gasifiers
Pre combustion Clean-
up beneficiation/washing
Technologies for utilization of Coal for Power Generation with minimal
pollutants discharged to the atmosphere (Reduced CO2, Sox, Nox,
SPM) at high conversion efficiency……….World Coal Institute.
CLEAN COAL
TECHNOLOGIES

7. CLEAN COAL
TECHNOLOGIES
Clean Coal Technologies (CCTs)
are defined as ‘technologies designed
to enhance:
Efficiency of conversion
Environmental acceptability of coal
extraction, preparation and use.

8. COAL FOR POWER
GENERATION
China and India are projected to account for30%
of the world’s increase in energy consumption
between 2000-2020 and 92% of increase in coal use.
The key environmental challenges facing the coal
industry are related to :
 Coal Mining
 Particulate emission
 Disturbance land me
 Acid rain
 Ozone and Waste disposal

9. INDIA AMONGST TOP SIX
EMITTERS OF CO2
Country Total emission Percentage of
(Million Tonnes of CO2) world emission
USA 5470 24%
China 3121 14%
Russian Federation 1456 6%
Japan 1173 5%
Germany 884 4%
India 881 4%

10. Note : Green House inventory
for India for Energy Sector
(Million Tonnes of CO2)
Energy Sector CO2 CO2 equivalent
(CO2+CH4+NOx)
Total Emission 508 565
(58% of total) (64% of total)
Source : IAE : 1999

11. PER CAPITA EMISSIONS OF CO2
Top 6 Polluters
World Developed countries
Parties
(Tonnes of CO2 per
capita)
Developing Countries
(Tonnes of CO2 per
capita)
Qatar 44.08
Bahrain 35.23
UAE 30.11
Kuwait 25.01
Singapore 23.47
U.S.A 20.50
USA 20.50
Luxemboury 20.42
Australia 16.52
Canada 15.76
Finland 12.47
Estonia 12.47
Qatar 44.08
Bahrain 35.23
U.A.E. 30.11
Kuwait 25.01
Singapore 23.47
Saudi Arabia 13.27
Note : Per capita CO2 equivalent emissions for India in 1990 are estimated to be
1.194 tonnes or 325 kg of Carbon per capita. This contribution 58% of National
Emissions and 4% of global emission.
Source : IEA 1999 & UNDP 1998.

12. COST OF VARIOUS CO2 MITIGATION
OPTIONS FOR INDIAN POWER SECTOR
Potential
Technologies
1. Co-generation
2. Combined Cycle
3. PFBC
4. IGCC
5. Supercritical
6. Coal Washing
Green house
gas emission
reduction (kg/kWh)
1.50
0.96
0.18
0.23
0.18
0.125
COST (Rs/Tonnes CO2)
.
480
2600
24000
16000
16000
8500
Source: ADP 1998

13. Zero Emission Technology
(ZET)
This technology combines and forms a part of :
 Clean Coal Technologies
 Solid to liquid fuel technology
 GHG mitigation technology
 Clean Development Mechanism for power sector
 Non-CFC Refrigerant and Non-CFC Aerosol Propellant
Technology
 Clean Aviation Fuel or ATF for aircraft
 Substitute LPG for domestic use.

14. Measures to achieve Sustainable
Development
Promoting CCTs, including carbon
sequestration is essential to a balanced cost
effective climate change response
Developing countries where coal combustion
efficiencies are low CCT promotion a need of
the day.

15. EFFICIENCY IMPROVEMENT FORECAST
CONVENTIONAL Vs IGCC ( Courtesy BHEL)
60
55
50
45
40
35
30
1990 1995 2000 2005 2010
Year of commercial use
Net
Thermal
Efficiency
(%)
Ceramic gas
turbine
566 C
o 600 C
o
623 C
o
1300 C
o 1500 C
o
540 C
o
650 C
o
1184 C
o
IGCC (15 C Amb)
IGCC (Indian Condition)
Super Critical PC Power Plant (15 C Amb.)
o
Super Critical PC Power Plant (Indian Condition)
o
Sub Critical PC Power Plant (Indian Condition)

16. 570
256
384
380
0
100
200
300
400
500
600
CO2
MMT
2.8
4.3
10
6.6
0
5
10
15
SO2
MMT
85
128
13.3
20
0
50
100
150
ASH
MMT
No Change Scenario
Specific Coal Consumption
=0.75 KG/KWH
Coal
Ash : 43%
Sulphur : 0.6%
Ideal Scenario
Specific Coal Consumption
=0.35 KG/KWH
Coal
Ash : 15%
Sulphur : 3%
POLLUTANT GENERATION FROM PC PLANTS
1997
1997
1997
1997
1997
1997
2002
2002
2002
2002
2002
2002

17. SOx NOx Particulates
0
10
20
30
40
50
60
70
80
90
100
110
120
PERCENTAGE
OF
PC
PLANTS
PC
IGCC
PFBC
PC+FGD
RELATIVE EMMISSION

18. SUPER CRITICAL UNITS
 Standardized Unit Size 660 MW, 246 ata, 537 o
C
 Station Size 2x660 MW (Minimum)
 Common Off site facility
 FW Temperature 270 o
C – 275 o
C with 6 Heaters.
Total Capacity Planned 14,560 MW *
Number of Units 22 Units
* Includes 6x720 MW and 2x500 MW Imported sets.

19. Main advantages of
Super-Critical Steam Cycle
 Reduced fuel cost due to improved thermal efficiency
 Reduction of CO2 emissions by 15% per unit of Power
generated compared to sub-critical
 Very good part load efficiencies
 Plant costs are comparable with sub-critical units

20. Current State-of-Art
Super-critical Steam Power Generation Plants
Pressure - 300 bar
Temperature - 600oC
Efficiency - 45% (LHV Basis)
Nickel based alloys allows up 650oC
By the year 2005 - 620 oC
By the year 2020 - 650-700 oC
Cycle Efficiency - 50-55%

21. R&D IN SUPERCRITICAL
TECHNOLOGY
Main Thrust Areas :
 Materials & Metallurgy for components of boiler &
turbine subjected to high temperature and high
pressure.
 Supercritical cycle optimization -incremental heat rate
improvement
 Retrofit of supercritical boiler to subcritical PC boiler
 Fluidized bed supercritical steam cycles
 Once through HRSGs with supercritical parameters
 Multi-reheat supercritical boilers with double/triple
reheater.

22. EXPECTED BENEFITS:
 Coal Saving 1,565,200 Tonnes
 Co2 Emission Reduction 1,909,544 ”
 SO2 Emission Reduction 11,648 ”
 Ash Reduction 661,752 ”
SUPER CRITICAL SCENARIO

23. COAL BASED COMBINED CYCLE PLANT
Routes
Combustion Gasification
Hot Flue gas under pressure
drives the G.T.
Pressurized gasification
process produces fuel for
G.T.
Pressurized
Fluidized – BED
Combustor (PFBC)
Options Available
 Moving – BED
 Fluidized – BED
 Entrained – BED

24. COAL BASED
COMBINED CYCLE POWER GENERATION
 Offers Plant efficiency over 44% with advanced GT
 Has Lower emission of gaseous and solid pollutants
 Accept Inferior and varying quality of coals
 Lower water requirement
 Capability of phased construction and retrofitting

25. IGCC TECHNOLOGY ...
 Gasification of coal is the cleanest way of utilization of coal,
while combined cycle power generation gives the highest
efficiency.
 Integration of these two technologies in IGCC power
generation offers the benefits of very low emissions and
efficiencies of the order of 44-48%.
 The comparative indices show that in case of IGCC,
emission of particulate, NOx and SOx are:
7.1%, 20% and 16%, respectively, of the
corresponding emissions from PC plant.

26. IGCC ...
 Environmental performance of IGCC plants far exceeds that
of conventional and even supercritical plants.
 Three major areas of technology that will contribute to
improvements in IGCC are :
 hot gas de-sulfurisation
 hot gas particulate removal
 advanced turbine systems

27. DEVELOPMENTAL GOALS FOR IGCC
 To utilize India’s low grade coal for power generation
with improved plant efficiency.
 To introduce coal gas in Natural Gas based Combined
Cycle Plants in a phased manner.
 To increase power generation capacity at the level of
present emission.
 To develop state of Art Technology for Indigenous and
Export Markets.

28. Gasifier
Raw Gas
Cooler
Combustion
Chamber
Comp. Turb.
Alternator
Air
COAL
Ash
Exhaust
Gases
Condenser
WHB
Alternator
ST
Air
Fuel
Steam
Gas
Clean Up
Booster
Steam
IGCC

29. IGCC DEVELOPMENT PROGRAM IN INDIA
MAJOR MILE STONES:
 Choice of gasification for high ash coals by BHEL
 6.2 MW IGCC demonstration plant established by BHEL both with
Moving Bed and Fluidized Bed.
 Coal Characterization by BHEL & IICT for gasification application.
 Intensive data generated by IICT on oxygen-steam gasification in their
Moving Bed gasifier.
 Task force CEA, CSIR, NTPC & BHEL constituted to assess
technological maturity & Financial requirement for a green field IGCC
plant of 100 MW capacity at Dadri (NTPC).
 BHEL, CSIR & NTPC prepared proposal for setting up of this 100 MW
IGCC demonstration plant.

30.  Circulating Fluidized Bed Combustion
(CFBC) technology has selectively been
applied in India for firing high sulphur
refinery residues, lignite, etc.
CFBC Technology is superior to PC Power
Plant Technology:
 Lower NOx formation and the ability to
capture SO2 with limestone injection the
furnace.
Circulating fluidized Bed Combustion

31.  Good combustion efficiencies comparable to PC
Power Plants.
 The heat transfer coefficient of the CFB furnace is
nearly double that of PC which makes the furnace
compact.
 Fuel Flexibility: The CFB can handle a wide range
of fuels such as inferior coal, washery rejects, lignite,
anthracite, petroleum coke and agricultural waste
with lower heating.
Circulating fluidized Bed Combustion

32. Steam to Super Heater
Cyclone
Furnace
Coal Feed
Hopper
Ash Cooler
Back-Pass
ESP
External
Heat-Exchanger
HPAir
Circulating Fluidised Bed Boiler

33. CFBC Vs Other Clean Coal
Technologies
At present pulverized fuel firing with FGD are less costly
than prevailing IGCC technology. However, firing in CFB
Boiler is still more economical when using high sulfur lignite
and low-grade coals and rejects.
0.8-0.98
1.49
1.0
Relative O&M
Cost/kW
1.15-1.42
1.03-1.19
1.0
Relative Capital
Cost/kW
41-42
36.7
34.8
Cycle Eff. %
IGCC
PF+FGD/SCR
CFBC
ITEM

34.  Renovation & Modernization (R&M) and Life
Extension (LE) of old power plants is a cost-
effective option as compared to adding up green
field plant capacities.
 Growing environmental regulations would force
many utilities within the country to go for
revamping these polluting old power plants using
environmentally benign CFBC technology.

35.  Sustainable Power Development calls for
adoption of Clean Coal Technologies like
Supercritical cycles, IGCC and FBC
technologies
 Supercritical Power technologies may
selectively be used for Pit Head power
generation using washed coal
SUMMERY

36.  IGCC can revolutionize the power generation
scenario in India, once the commercial viability of
technology with high ash coals is established at the
proposed 100 MW plant.
 The success of the project will largely depend on
maturity of Fluidized bed gasification technology
for high ash Indian Coals.
 CFBC technologies are particularly useful for Boiler
Emission reduction through revamping of old
polluting plants.
SUMMERY