9th Annual SECA Workshop, August 6, 2008

Eric GrolUS Department of EnergyNational Energy Technology Laboratory

Dale Keairns and Dick NewbyScience Application International Corporation (SAIC)National Energy Technology Laboratory

August 6, 2008

Integrated Gasification Fuel Cell (IGFC) System Studies

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Office of Systems, Analyses & Planning Systems Analysis Team

• Assessment of state-of-the-art and advanced technologies– Guide Research

• Compare potential of advanced technologies to current SOA• Identify process conditions & performance targets

– Inform policy & regulation• Unbiased assessments of technology options

– Overall technical & environmental performance• Efficiency, resource use (feedstocks, water), emissions

(stack & life-cycle)

3

CO2 Emissions – Why is this relevant?

• Supreme Court ruled that carbon dioxide is classified as a pollutant under the 2007 Clean Air Act, therefore the U.S. Government has the authority to regulate CO2emissions

• Carbon capture and sequestration is an administration priority – NETL’s role is to assist in the development of technologies that enable this goal

4

Water Use – Why is it important?

• USGS reports that power generation is second only to agriculture in total U.S. freshwater consumption1

• Projected population shifts to western and southeastern U.S. will result in thermoelectric growth that exceeds the national average to 20302

• Limited freshwater in these areas could be inadequate to meet projected power generation needs

1. “Estimate Use of Water in the United States in 1995,” http://www.usgs.gov/watuse/pdf1995/pdf/circular1200.pdf2. “Estimating Freshwater Needs to Meet Future Thermoelectric Generation Requirements,”

http://www.netl.doe.gov/technologies/coalpower/ewr/pubs/2007%20Water%20Needs%20Analysis%20-%20Final%20REVISED%205-8-08.pdf

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Energy Efficiency – Why is it Important?

• NETL Power Systems Goal 45-50% net efficiency (coal HHV) by 2010 and 55-60% net efficiency (coal HHV) by 2015

• Energy Information Administration (EIA) Annual Energy Outlook (AEO) 2008 predicts1:– 41% increase in energy produced by coal plants from 2006 to

2030– Percentage of nation’s power generated by coal increases from

49% to 54%• Coal costs have risen drastically since 2005

– Increased efficiency lowers capital and operating costs

1. http://www.eia.doe.gov/fuelcoal.html

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Historic Coal Prices1

Since 2005, coal prices have at least doubled

1. http://www.eia.doe.gov/cneaf/coal/page/coalnews/coalmar.html

$0

$20

$40

$60

$80

$100

$120

$140

$160

Apr-05 Oct-05 May-06 Nov-06 Jun-07 Jan-08 Jul-08

Coa

l Cos

t - D

olla

rs p

er S

hort

Ton

Northern AppalachiaIllinois BasinPowder River Basin

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System Integration Choices

Gasifier

-Coal-Petcoke-Biomass-Waste Material

-Temperature-Pressure-Reactor Concept-Heat Source-Catalytic/Non-Catalytic

Heat Recovery/ParticulateRemoval

-Radiant-Convective-Water Quench

WaterGas Shift-Sweet Shift-Sour Shift-No Shift

GasCleaning

-Dry Gas Cleaning-Humid Gas Cleaning

PowerIsland

-SOFC Design and Integration-Anode Offgas Treatment-Waste Heat Recovery-Steam Bottoming Cycle-Carbon Capture

Stack Gas

Catalytic/Non-Catalytic

Dry/Humid Gas Cleaning

SOFC Design and IntegrationCarbon Capture

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Baseline IGFC Combined Cycle Atmospheric SOFC with combined anode and cathode offgas

• Single pass SOFC • Precombustion CO2 capture (Selexol process)• Waste heat recovery in subcritical steam cycle

(1600psia/1100 ºF)

Gasifier

Coal

Air Separation Unit

Air

O2

Gas Cleanup(NH3, Cl, Particulate

Removal)

Solid Oxide

Fuel Cell

H2OO2N2

HRSG

Boiler FeedwaterSupercritical

Steam

Condenser

Steam Turbine

Air

Water Gas Shift(CO + H2O CO2 + H2)

Selexol

H2SCO2

Combined anode,cathode offgas

• 43.3% system efficiency (coal HHV basis)

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Solid Oxide

Fuel Cell

H2OCO2H2CO

Oxycombustor

H2OCO2

HRSG

Boiler FeedwaterSupercritical

Steam

Condenser

Steam Turbine

AirHeat Recovery

N2O2

High PressureCO2

Gasifier

Coal

Air Separation Unit

Air

O2

Water Gas Shift(CO + H2O CO2 + H2)

Selexol

System AdvancementSeparated Anode and Cathode Offgas Streams

• Separate anode, cathode offgas streams• Recover residual anode fuel heating value in oxycombustor

– No dilution of products with N2

• Reaction products are CO2 and H2O, which can be condensed• Eliminate requirement for precombustion CO2 capture

Anode offgas

Cathode offgas

• 44.2% system efficiency (coal HHV basis)– 1% improvement by separating anode, cathode offgas

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IGFC Efficiency Comparison to PC, IGCC

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

Supercritical PC IGCC IGFC System (Separate Streams)

Net

Sys

tem

Effi

cien

cyNo CO2 CompressionNo CO2 CaptureWith CO2 Capture

`

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IGFC Water Consumption Comparison to PC, IGCC

Water consumption less than half that of IGCC with CO2 capture

0

200

400

600

800

1000

1200

1400

IGFC Combined Cycle IGCC Supercritical PC

Gal

lons

/MW

hIGFC stack gas H2O is recoverable, due to absence of N2

(separate anode, cathode offgas streams)

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Effect of High Methane Syngas

• For SOFC, syngas composition should be high in CH4

– Endothermic CH4 reforming can serve as a heat sink to exothermic H2 oxidation, reducing stack thermal management load (cooling air blowers)

– H2 + ½ O2 H2O EXOTHERMIC– CH4 + H2O CO + 3H2 ENDOTHERMIC

• Select a gasifier that produces syngas with high CH4concentration

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Gasifier Selection

• Catalytic coal gasification concept produces high methane yields at low gasification temperature

• Concept of catalytic coal gasification to produce SNG is not new– Great Point Energy’s bluegasTM process– Catalytic gasification concept to produce pipeline-

quality SNG from coal and other feedstocks• Assumed for this analysis that SOFC can handle up to

25% CH4

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IGFC Combined Cycle with Catalytic Gasifier

• Low temperature, catalytic gasifier (high cold gas efficiency)• High methane syngas (reduced stack cooling load)• Separate anode and cathode offgas (no precombustion CO2

capture)• Waste heat recovered in supercritical steam cycle

Catalytic, low temperature steam gasification process

• 54.5% efficiency (coal HHV)~10% efficiency improvement by using different gasifier

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IGFC Efficiency Comparison to PC, IGCC

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

55%

Supercritical PC IGCC IGFC System (SeparateStreams)

IGFC System with Cat.Gasifier

Net

Sys

tem

Effi

cien

cy

No CO2 CompressionNo CO2 CaptureWith CO2 Capture

`

Entrained Flow Slagging Gasifier(Non Catalytic)

Catalytic Coal Gasification Concept

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IGFC Water Use Comparison to PC, IGCC

0

200

400

600

800

1000

1200

1400

Unoptimzed IGFCCombined Cycle

IGFC Combined Cyclewith Catalytic Gasifier

IGCC Supercritical PC

Gal

lons

/MW

hIGFC stack gas H2O is recoverable, due to absence of N2

(separate anode, cathode offgas streams)

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Improved IGFC System

• SOFC with minimal overpotential loss (high efficiency)• Humid gas cleaning system (maintains H2O in vapor phase)• High methane gasifier (catalytic coal gasification)• Pressurized SOFC operation

– Voltage improved by pressurized operation– High pressure anode offgas for expansion through turbine

• Elimination of steam cycle, reduced water footprint

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IGFC Combined Cycle with Catalytic Gasifier and Pressurized SOFC

Catalytic, low temperature steam gasification process

Pressurized SOFC

18 bar

• Low temperature, catalytic gasifier (high cold gas efficiency)• High methane syngas (reduced stack cooling load)• Separate anode and cathode offgas (no precombustion CO2

capture)• Pressurized SOFC• Turbine expander after oxycombustion (18:1 PR)• 58.6% efficiency (coal HHV)

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IGFC Efficiency Comparison to PC, IGCC

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

55%

60%

Supercritical PC IGCC IGFC System(Separate Streams)

IGFC System withCat. Gasifier

IGFC System withCat. Gasifier,

Pressurized SOFC

Net

Sys

tem

Effi

cien

cy

No CO2 CompressionNo CO2 CaptureWith CO2 Capture

Entrained Flow Slagging Gasifier

Catalytic Gasifier

Catalytic GasifierPressurized SOFC

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IGFC Water Use Comparison to PC, IGCC

0

200

400

600

800

1000

1200

1400

Unoptimzed IGFCCombined Cycle

IGFC CombinedCycle with

Catalytic Gasifier

IGFC Cycle withCat. Gasifier and

PressurizedSOFC

IGCC Supercritical PC

Gal

lons

/MW

hIGFC stack gas H2O is recoverable, due to absence of N2

(separate anode, cathode offgas streams)

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Conclusions

• Fuel cell power system is attractive with respect to carbon capture, water use, and efficiency

• System advances needed to achieve high efficiency cycles:– High methane syngas (catalytic gasifier)– Humid gas cleaning– Achieve targeted SOFC performance

• Continued interaction between systems analysis group and research program