lecture gasifier
TRANSCRIPT
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Highlights
What is IGCC? Why IGCC? Historical Aspects Working Principle Advantages of IGCC
IGCC in NTPC perspective Barriers to Deployment Conclusion
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Why IGCC ?
CONVENTIONAL COAL PLANTS :
Future challenges :Comparatively lower efficiency & Higher
emissionsKyoto Protocol Norms & Strict norms of loanpolicyLimited Coal Stock & Other options areexpensive
Land cost & Ash disposal
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Why IGCC ?NON CONVENTIONAL: Future
challenges : Low capacity Low efficiency High capital cost Less flexibility
Lesser reliabilityTo address these challenges, new coal utilization technologies are being developed. One of the more
promising of these is Integrated Gasification Combined Cycle (IGCC)
power generation
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In the 1970s , interest in coal gasification revived because of increasing cost and less availability of
natural gas. Coal gasification, however, likely found its most
important market application in the 1980s and 90s .Driven primarily by environmental concerns over thetraditional burning of coal, gasification emerged as anextremely clean way to generate electric power.
By turning coal into a combustible gas that could becleansed of virtually all of its pollutant-formingimpurities and burned in a gas turbine, coal couldrival natural gas in terms of environmental
performance.
Historical Aspects
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How does IGCC work?
IGCC is a combination of two leadingtechnologies.
The first technology is called coalgasification , which uses coal to create aclean-burning gas (syngas).
The second technology is called combined-cycle , which is the most efficient method of
producing electricity commercially availabletoday
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End-productseeds Gas RefiningasificationIGCC Sc hem at ic
Coal
Biomass
PetroleumCoke/Resid.
Waste
FEEDSTOCK
MarketableSolid
Byproducts
GASIFIER
OXYGEN
STEAM
ASU
H2
STACK
FUELCELL
H2
ELECTRICPOWER
TRANSPORTATIONFUEL
STEAM
SULFUR/SULFURIC ACID
FUELCHEMICALS
PARTICULATES
SYNGAS
C C
CO 2
ELECTRICPOWER
ELECTRICPOWER
AIR COMP. + GT G
G
HRSG
STEAMTURBINE
WATER
CombinedCycle
SULFUR/SULFURIC ACID
FUELCHEMICALS
PARTICULATES
SYNGAS
SULFUR/SULFURIC ACID
FUELCHEMICALS
PARTICULATES
SYNGAS
SULFUR/SULFURIC ACID
FUELCHEMICALS
PARTICULATES
SYNGAS
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Advantages of IGCC Higher Efficiency Lower Emission Comparable Cost Multiple Fuel Options
Marketable Byproducts Lesser Area Requirement
Higher Output Less Solid Waste and Water Use
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Higher Efficiency As we have already discussed, currently IGCC efficiency
approaching 50%, With development of new gas turbine
concepts and increased process temperatures, efficienciesof more than60% can be achieved. Future concepts that incorporate afuel cellor fuel cell-gas
turbine hybrid could achieve evenhigher efficiencies. If any of the remaining waste heat can be channeled into
process steam or heat, perhaps for nearby factories ordistrict heating plants, the overall fuel use efficiency ofuture gasification plants could reach70 to 80percent.
Higher efficiencies translate into moreeconomical electricpower and potential savings for ratepayers. A moreefficient plant also usesless fuel to generate power.
Advantages of IGCC
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Plant efficiency can be improved furtherby:
1. Injecting the nitrogen from the airseparation unit into the fuel gas priorto the gas turbine
2. Utilizing air from the gasturbine/compressor in the airseparation unit.
Higher Efficiency (contd)
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Lower Emission
High SO 2 removal (e.g., 99 % or higher)and low-NO
Xemissions (below 50 ppm )
are achieved.
The emissions of particulates, NOx andSO 2 from IGCC units meet all currentstandards .
On most units, sulphur is produced inelemental form as a by-product .
Advantages of IGCC
SO X & NO X EMISSION
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Lower Emission
Advantages of IGCC
Carbon dioxide
Up to 100% of Carbon dioxide can be captured fromthe coal syngas (carbon monoxide and hydrogen)through a water/gas shift process
Carbon capture at IGCC plants is significantly easierand much more economic than at conventionalpulverized coal plants and more economic on a $/tonbasis than at natural gas plants
Even without carbon capture and sequestration,IGCC plants are more efficient than conventional coalplants and emit less CO 2.
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The environmental benefits stem from the capability to cleanseas much as 99 percent of the pollutant-forming impurities fromcoal-derived gases.
Sulfur in coal, can be extracted in either a liquid or solid formthat can be sold commercially.
In an IGCC plant, the syngas produced is virtually free of fuel-bound nitrogen. NOx from the gas turbine is, therefore,limited to thermal NOx. Diluting the syngas allows for NOx
emissions as low as 15 parts per million. Thus avoids acidraining.
Multi-contaminant control processes are being developed thatreduce pollutants to parts-per-billion levels and are effective incleaning mercury and other trace metals in addition to othe rimpurities.
Advantages of IGCC
Envi ronm en t a l Benef i t s
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Comparable Cost IGCC cost projections range from US$1200 to
1400/kW; 10 to 30 percent higher than for pulverized-coal with wet scrubbers.
US Department of Energy (DOE) forecasts that by the year 2010, the operating cost of IGCC based electricity power generation could be inthe order of 3.7/kWh ( 1.5Rs/kWh ), which ischeaper than advanced coal fired power plantand also comparable to natural gas firedcombined cycle units
A capital cost of around 1000$/kW ( 4.3CroreRs/kW is also achievable.
Advantages of IGCC
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IGCC Plant Capital Cost Trends
Comparable Cost
0
2
4
6
8
10
12
14
16
1975 1980 1985 1990 1995 2000 2005 2010 year
C r o r e R s p e r
M W
Advantages of IGCC
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Multiple Fuel Options
COAL
BIO MASS
PETROLEUM/COKE RESIDUE
WASTE
Advantages of IGCC
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Marketable Byproducts
The gasification process in IGCC enablesthe production of not only electricity, buta range of chemicals, by-products for industrial use, and transport fuels, e.g.; Hydrogen
Ammonia Methanol Sulphur Slag
Advantages of IGCC
FUEL
CHEMICALS
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Pathway to : Hydrogen Economy Research and development in recent years has focused onhydrogen fuel cells which hold great promise as low-
pollution automobile engines if certain difficulties can beovercome. Water, the only waste product of a hydrogen-oxygen fuel cell, is non-polluting and can be used to cool theengine. The oxygen the cells need is readily available in air.
Hydrogen, however, is not so readily available, and there isno existing delivery system to convey hydrogen to all theplaces people would need it to power their cars. In addition,
pure hydrogen is not abundant enough to provide power forall the cars on the road today. Instead, hydrogen wouldneed to be extracted from other substances, a process thatrequires energy and produces pollutants.
In an IGCC plant Hydrogen is produced as byproductwithout causing pollution and consuming extra energy
Advantages of IGCC
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Higher Output Using syngas in a gas turbine increases its
output, especially when nitrogen from anoxygen blown unit is fed to the turbine. Thus
a turbine rated at 170MW when fired onnatural gas can yield 190MW or more onsyngas .
Furthermore, output is less dependent onambient temperature than is the case withnatural gas.
Advantages of IGCC
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Unit Size A number of demonstration units, mainly around
250 MW size are being operated in Europe and theUSA. Most use entrained flow and are oxygenblown, and one is based on a fluidized bed, and isair-blown.
The 235 MW unit at Buggenum in theNetherlands , started up in 1993.
Three plants are in the USA at Wabash River inIndiana; Polk Power near Tampa in Florida andPion Pine in Nevada.
The largest unit is that at Puertollano in Spainwith a capacity of 330 MW.
Advantages of IGCC
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Lesser Area Requirement
Compact Process No Requirement of Ash Handling
System & Ash Dykes
Advantages of IGCC
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Advantages of IGCC
Less Solid waste and water use
Solid Wastes Less Volume : IGCC produce about half the solid
wastes of conventional coal plants.
Better Form : IGCC solid wastes are less likely toleach toxic metals than fly ash from conventionalcoal plants because IGCC ash melts and is vitrified
(encased in a glass-like substance). Water Use
Less Water : IGCC units use 20%-50% less water than conventional coal plants and can utilize drycooling to minimize water use.
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For Developing Countries
Entrained IGCC technologies are suitable for low-ashcoals. High-ash coals, such as those in India, wouldrequire fluidized-bed gasification processes.
The primary constraints to the application of gasificationand IGCC plants in developing countries are that thetechnology needs further demonstration, the costs arehigher than those of competing technologies, and the factthat environmental regulations in developing countries donot require the high SO2 removal and low-NOxemissions achieved by IGCC.
Kyoto Protocol
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IGCC in NTPC
FR shall be prepared for the IGCC projectat Dadri Pursue with BHEL for submitting the FR
for the other IGCC demo project Complete techno economic study of
Underground Coal gasification (UCG) shall be taken up. Possible locations could be
Pakri Barwadih and Singrauli area
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Barriers to Deployment : IGCC Power Industry Culture
This is a chemical plant. Power companiesunderstand combustion, not chemical units.
Perceived financial risk
Technology unfamiliarised Why build an IGCC if you can get a permit
for a conventional coal plant?
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Pioneer ing Gas i f i c at ion Plan t s
First major use of coal gasification to generate electricpower : Southern California Edison's experimentalCool Water project near Barstow, California, United
States
Took place in the mid-1980s
Capacity : 100MW
Technical foundation for future integrated gasificationcombined cycle (IGCC) power plants
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World's largest single traingasification combined cycle plant :
The Wabash River CoalGasification Repowering Project,
West Terre Haute, Indiana, UnitedStates
The plant can generate 292 MW ofelectricity -- 262 MW of which aresupplied to grid
The plant started full operations inNovember 1995
Pioneer ing Gas i f i c at ion Plan t s
In 2002 DOE approved plans to site the world's first clean coaltechnology-powered fuel cell.
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Biggest Boost in IGGCThe Tampa Electric's PolkPower Station near Mulberry,Florida, United States
Capable of generating 313MWof electricity 250MW of whichare supplied to the electric grid
operating since 1996
Removes more than 98 % ofthe Sulfur in coal, converting itto a commercial product.
Pioneer ing Gas i f i c at ion Plan t s
Nitrogen oxide emissions are reduced by more than 90 %
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Pioneer ing Gas i f i c at ion Plan t sAn American dreamThe Dakota Gasification Company, United States
The 1970s energy crisis spawned avision of greater U.S. energy
independence.The Synfuels plant began operatingin 1984 and today produces more
than 54 billion standard cubic feet ofnatural gas annually..
In addition to natural gas, the Synfuels plant producesfertilizers, solvents, phenol, carbon dioxide, and otherchemicals.
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Types o f Coa l Gas i f i c a t i on Reac t o r s
T h i s s ho w s t h e t h r e e m a i n c o a l g a s i fi c a t i o n p r o c e s s e s .
FIXEDBED
FLUIDIZEDBED
ENTRAINEDFLOW