Transcript Coal Gasification-Air Pollution and Permitting

Coal Gasification-Air
Pollution and Permitting
Implications of IGCC
USEPA Air Innovations Conference
John Thompson
Clean Air Task Force
August 10, 2004
Presentation Topics
1.
Integrated Gasification Combined Cycle (IGCC)



2.
3.
Overview
Environmental Performance
Cost
Barriers to Deployment
Permitting Implications
2
IGCC: What is it?


Chemical conversion of coal to synthetic gas for
combustion in a modified gas turbine
Inherently cleaner process because:
– Coal is not combusted.
– Pollutants are removed with greater efficiency because
clean-up occurs while syngas volume is relatively small
compared with flue gas.
3
IGCC Schematic
Feeds
Gasification
Gas Refining
End-products
Combustion Turbine
Oxygen
Electricity
HRSG
Syngas
Steam
Chemicals
Hydrogen
Syngas
MERCURY
SULFUR /CO2
REMOVAL
REMOVAL
Coal
Ammonia
Syngas
H S
2
Methanol
SULFUR
RECOVERY
Sulfur
Solids
Mercury
CO2 Sequestration Option
4
Tampa Electric – Polk Power Station
.
250 MW – operating since 1996
5
IGCC vs. conventional coal plants
• An IGCC places the chemical plant in the front end of plant.
• In contrast, a conventional coal plant is less efficient because
it places a chemical plant at the back end, attempting to
capture pollutants after combustion and much dilution.
6
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 to leach
toxic metals than fly ash from conventional coal 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 dry cooling to
minimize water use.
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Carbon dioxide



Up to 100% of the carbon in syngas can be captured at IGCC plants
with commercially available technology.
Carbon capture at IGCC plants is significantly easier and much more
economic than at conventional pulverized coal plants and more
economic on a $/ton basis than at natural gas plants.
Even without carbon capture and sequestration, IGCC plants are
more efficient than conventional coal plants and emit less CO2.
8
Air Emissions

IGCC has fewer air emissions than a conventional
supercritical pulverized coal plant (SCPC)
Sulfur Dioxide
Nitrogen Oxide
Carbon Monoxide
VOC
Hg
PM
Sulfuric Acid Mist
SCPC
IGCC
0.15
0.03
0.07
0.07
0.12
0.03
0.0035 0.0017
1.1E-06 5.6E-07
0.018
0.011
0.01 0.0005
% Increase
due to SCPC
400%
0%
300%
106%
100%
64%
1900%
Not es: Elm Road Wisconsin permit limits issued by WDNR January 2004, expressed
in lb/MMBt u. T his air permit is a good comparison of IGCC and SCP C because
it is for bot h t echnologies at t he same sit e using t he same P it t sburgh #8 bit uminous coal.
9
IGCC costs are close to
conventional coal plants

IGCC may cost slightly more than convention plants
without carbon capture and sequestration (CCS) but
costs much less when carbon is reduced.
Cost of Electricity in $/MWh
Bituminous
Without CCS
With CCS
Conventional
Conventional
Coal
IGCC
Coal
IGCC
46.6
45.8-48.3
75.4
61-67
Subbituminous
Source: EPRI, 2004
44
48-54
64-97
61
10
Barriers to Deployment

Power Industry Culture
– This is a chemical plant. Power companies
understand combustion, not chemical units.

Perceived technical and financial risk.

Why build an IGCC if you can get a permit
for a conventional coal plant?
– Is IGCC BACT?
11
Best Available Control Technology
(BACT) and IGCC

If a conventional coal plant is proposed,
should IGCC be evaluated as an alternative
option?
– States
Yes:
No:
Undecided:
Illinois, Montana, New Mexico
Wisconsin, West Virginia
Many states
– Federal

May issue an opinion through permit appeal decision.
Have been reluctant to decide in other forums.
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Some Closing Observations
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More IGCC plants are being proposed than in the past.
IGCC plants are vastly cleaner than conventional coal-fired
power plants.
Costs of IGCC are close to that of conventional coal-fired
power plants.
Regulatory crossroads- Is IGCC BACT for producing electricity
from coal?
You’ll never know if your state’s air permit applications don’t
compare IGCC to conventional coal plants AND do the
comparison accurately!!!
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