ClearStack Combustion Corporation

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August 17 - 19, 2005 Henry B. Gonzalez Convention
Convention Center San Antonio, Texas
Multi-Pollutant Emissions Control Ashworth
Combustor Retrofit to AEG Hutsonville Unit 4
ClearStack Combustion Corporation Bob
Ashworth  Ameren Services Tom Callahan Promecon
USA Todd Sommer


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Ashworth Combustor Features
PC- fired, 3-Stage Combustor Limestone
addition ( slag fluxing, S Hg capture )
NOX emissions lt 0.15 lb/106 Btu SO2
reduction 70 Mercury reduction ( 90 wt
) Particulate other metal air toxic
reductions HCL, HF SO3 reductions
CO2 reduction w/biomass co-firing Fly
ash/slag sales
T- Fired Application
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Lincoln Developmental Center
Ashworth 3-Stage Combustor on LDC Unit 2
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Environmental Performance _at_ LDC
Firing Illinois 5 Bituminous Coal
NOX Low as 0.095 lb/106 Btu
SO2 1.70 lb/106 Btu _at_ Ca/S ratio of 0.85
(72 Reduction) CO 15 - 30 ppmv _at_3 O2
dry Hg
Near quantitative removal Carbon Slag
0.2 wt C, Fly Ash 5 wt C)
Chlorine/Fluorine 14 Cl 26 F Reduction
Other Air Metal Toxic Reductions 80 to 100
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Engineering Assessment
Ashworth Combustor Retrofit to AEG Hutsonville
Boiler 6 - Unit 4 (85 MWe Tangential Coal-Fired
Boiler) Funded by IL CCRB, ClearStack
AEG Assessment Performed by ClearStack Promecon
USA Alstom United Conveyor Sargent and Lundy AEG
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Boiler 6 Retrofit
Location of OFA nozzles ( 4-corners )
Hot Air to 2nd Stage
3- Ashworth Gasifiers
Hot Air to 1st Stage
3-Corner Gasifier Firing, w/4-corner OFA
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Ashworth Gasifier Conceptual Design
BFW Headers
Fuel gas Outlet
Coal Entry
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Simple Gasifier Furnace Integration

• Gasifier cooling integrated with BFW heating
• 1. Replaces last stage BFW extraction
  steam heater
• (Increases capacity by 3.5 MWe)
• 2. Placed between economizer outlet and
  steam drum
• Slag sluiced from gasifiers using condenser
  outlet water
• Use existing pressure vessel for steam-water
  separator required for startup

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Tangential Swirl Effect
Velocity, fps
Baseline
Gasifier
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Temperature Profile
In detail design phase we will evaluate tiltable
2nd stage air to increase outlet temperature.
Nose
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Oxygen Distribution
O2, wt
Baseline
Gasifier
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Carbon Monoxide Distribution
CO, ppmwd
160 - 250 ppmw
7- 8 ppmw
Baseline
Gasifier
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Nitrogen Oxide Distribution
NOX, ppmv dry
NOX, ppmv dry
Outlet 86 ppmvd 0.095 lb/106 Btu
Outlet 481 ppmvd 0.53 lb/106 Btu
Baseline
Gasifier
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SO2, Hg and Particulate Capture

• Projected Sulfur Capture 72
• CaO H2S CaS? H2O
• Projected Mercury Capture 90 to 100
• Cao Hgo CaoHgo?
• CaO HgO CaHgO2?
• Particulate capture estimated at 65 via CFD
  modeling

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Conclusions
With the Ashworth Combustor, significant
operating savings occur because it is a
multi-pollutant device that can take credits for
the reduction of three major air pollutants (NOX,
SO2 and Hg), not just one as with most
technologies. There is a potential to also
receive refined coal tax credits (over 5/ton).
This is true for any unit installed before the
end of 2009.   The technology is initially
earmarked for the retrofit of coal-fired power
plants having capacities of 200 MWe and less due
to the unfavorable economics of adding Selective
Catalytic Reduction, Wet Scrubbers, and Activated
Carbon Injection followed by a Baghouse, to
comply with current and future EPA emission
limits.