Jan. 2011

SO2/SO3/Hg and Corrosion Issue Results From DOE/NETL Existing Plants

Oxy-combustion Projects

January 25, 2011London, United Kingdom

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R. Boyle, 02/11/2009

• Only U.S. government owned & operated DOE national lab

• Dedicated to energy RD&D, domestic energy resources

• Fundamental science through technology demonstration

• Unique industry–academia–government collaborations

National Energy Technology LaboratoryWhere Energy Challenges Converge and Energy Solutions Emerge

West VirginiaPennsylvaniaOregon

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DOE/NETL CCS Program Goals

90% CO2 capture

99%+ storage permanence

Pre-combustion Capture (IGCC)

< 10% increase in COE1

Post- and Oxy-combustion Capture

< 35% increase in COE2

By 2020, have available for commercial deployment, technologies and best practices for achieving:

*Cost of Electricity includes 50 mile pipeline transport and saline formation storage, 100 years of monitoring

1. Impact of Cost Escalation on Power Systems R&D Goals—Re-baselining APS, CS & FC GPRA R&D Goals, DOE/NETL July 20082. Existing Plants, Emissions & Capture Program—Setting Program Goals, U.S. DOE/National Energy Technology Laboratory, Draft Final Report, February 2009

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Oxy-combustion Projects Overview

• Combustion/boiler testing– 15 MWth T-fired (Alstom)– Multi-scale wall fired (B&W, REI, Jupiter, Southern Research)– Cyclone (B&W)

• Coupon corrosion testing– NETL ORD– Foster Wheeler

• Flue gas purification systems– Air Products– Praxair– IPR System (NETL ORD & Jupiter)

• Advanced Oxy-combustion Systems– OTM (Praxair)– Chemical Looping (Ohio St. & Alstom)

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Pulverized Coal Oxy-combustionPartners: 1. Praxair (O2 Membrane, CO2

Purification)2. Air Products (CO2 Purification)3. Jupiter Oxygen (Burners) 4. Alstom (Pilot plant)5. B&W (Cyclone pilot test)6. Foster Wheeler (Corrosion)7. Reaction Engineering Int. (Retrofit)8. Southern Research Institute (Retrofit)9. NETL ORD (Modeling, CO2

Purification)

Challenges• Cryogenic ASUs are capital and

energy intensive• Existing boiler air infiltration• Corrosion and process control• Excess O2 and inerts (N2, Ar) CO2

purification cost

Today: 10 MWe wall-fired test (B&W)5 MWe T-fired pilot (Alstom)5 MWe burner pilot (Jupiter)

by 2015: 1st Gen (Cryogenic) demo.

2020: 2nd Gen demonstration*

Development Timeline

*O2 Membrane + USC materials + Adv. Purification + Adv. Compression

Project Types• “2nd Gen” oxyboiler designs

- Adv. Materials and burners• Existing boiler retrofits

- Air leakage, heat transfer, corrosion, process control

• Low cost O2 (membrane)• CO2 purification• Co-sequestration

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Boiler Material Development for Oxy-Combustion Foster Wheeler NA, Corp.

• Investigation of oxy-combustion effects on durability of boiler tube materials

• Computational fluid dynamic modeling will predict gas compositions

• Laboratory testing to determine effects on conventional and higher-alloy boiler tubes

Heat Flux

(Btu/hr-ft2)

Division Walls

Burners

OFA Ports

Waterwalls

Heat Flux

(Btu/hr-ft2)

Division Walls

Burners

OFA Ports

Waterwalls

Heat Flux

(Btu/hr-ft2)

Division Walls

Burners

OFA Ports

Waterwalls

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Oxy-combustion Coupon Studies(Foster Wheeler)

• Two Nominal 500 MWe Air-Fired Boiler Retrofits Studied– Wall-Fired and Tangential-Fired Configurations Compared

• 2.5% Sulfur Illinois # 6 and 0.3% Sulfur Eagle Butte Coals Us

• Ill # 6 Wall-Fired Boiler Uses 68% Flue Gas Recycle– Flue Gas Mixed with O2 Yields 28% O2 by Volume to Boiler– Maximum Furnace Wall Heat Flux ~5% Lower than Air-Fired

• Ill #6 Wall-Fired Boiler Has Highest Furnace Wall Reducing Zones

CO H2S CO2 H2O– Air-Fired 9% 0.14% 11% 8%– Oxy-Fired 20% 0.26% 48% 18%

• Ill #6 Wall-Fired Boiler Gases Selected for Corrosion Testing

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Gas Compositions Test Plan(Foster Wheeler)

20% CO 5% CO 2% CO 1% O2 5% CO 2% CO 1% O2 Oxy: 2% O2 Air: 3% O2

CO2 55% 67% 69% 70% CO2 13% 14% 14% CO2 69% 14%

H2O 18% 20% 20% 21% H2O 9% 9% 9% H2O 21% 9%

N2 7% 8% 8% 8% N2 73% 74% 76% N2 8% 74%

H2S 0.26% 0.07% 0.03% 0.00% H2S 0.08% 0.03% 0.00% H2S 0.00% 0.00%

SO2 0.17% 0.29% 0.30% 0.32% SO2 0.19% 0.21% 0.20% SO2 0.32% 0.20%

HCl 0.02% 0.02% 0.02% 0.02% HCl 0.02% 0.02% 0.02% HCl 0.02% 0.02%

Total 100% 100% 100% 100% Total 100% 100% 100% Total 100% 100%

GasWaterwall: Air-Fired Superheater/ReheaterWaterwall: Oxy-Combustion

Gas Gas

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Materials Test Plan(Foster Wheeler)

• Waterwalls– Tube Materials (SA210-A1, SA213-T2, SA213-T11)– Weld (T11 to T11)– Weld Overlays (309 SS, Inconel 622, VDM Alloy 33)– Thermal Sprays

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Materials Test Plan(Foster Wheeler)

• Superheater/Reheater– Tube Materials

• Conventional (SA213-T22, SA213-304H, SA213-317H)• Newer (SA213-T91, NF709, HR3C)

– Weld (T22 to 304H)– Weld Overlays (Inconel 622, VDM Alloy 33, Inconel

72)• Deposit materials refreshed every 100 hours• Three deposit compositions used for each WW and

SH/RH tests (Low, med, high sulfur)

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Laboratory Fireside Corrosion Exposures

Fireside Exposure Tests• Determine fireside corrosion ramifications in boilers refitted for

oxyfuel combustion.• Alloys of interest represent 4 currently used boiler alloys:

• T22 (for waterwalls)• T91 (for waterwalls and superheater/reheater tubes)• 347 (for superheater/reheater tubes)• 617 (for superheater/reheater tubes and weld overlays)

Tasks• Initial test to look at ash thickness• Exposure tests for 1000 hours with ash refreshment every 250

hours• Characterize exposed coupons in terms of corrosion kinetics

(primarily by section loss) and corrosion microstructures (by light microscopy, SEM, XRD, and elemental analysis)

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Fireside Corrosion Exposures—Waterwalls

Oxidative Conditions

450 °C

Gas Phase (2.5 O2) • Air-fired• Oxy-fired with CO2 recycle after

FGD• Oxy-fired with CO2 recycle before

FGD

Ash Phase• Base Case: 5Na2SO4, 5K2SO4,

30Fe2O3, 30SiO2, 30Al2O3

• Base case with 10FeS (for 10Fe2O3)

• Base case with 5C (for 2.5SiO2, 2.5Al2O3)

Reducing Conditions

450 °C

Gas Phase (5 CO)• Air-fired• Oxy-fired with CO2 recycle after

FGD• Oxy-fired with CO2 recycle before

FGD

Ash Phase• Base Case: 5Na2SO4, 5K2SO4,

30Fe2O3, 30SiO2, 30Al2O3

• Base case with 1NaCl (for 0.33Fe2O3, 0.33SiO2, 0.33Al2O3)

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Fireside Corrosion Exposures—SH/RH

Oxidative Conditions

700 °C

Gas Phase (2.5 O2) • Air-fired• Oxy-fired with CO2 recycle

after FGD• Oxy-fired with CO2 recycle

before FGD

Ash Phase• Base Case 5Na2SO4, 5K2SO4,

30Fe2O3, 30SiO2, 30Al2O3

Fundamental Conditions

650 °C

Gas Phase • Air• 70CO2+30H2O• 70CO2+30H2O+SO2

Ash Phase• A: 50SiO2-25Al2O3-12.5CaO-12.5Fe2O3

• B: 49SiO2-25Al2O3-12.5CaO-12.5Fe2O3-1K2SO4

• C: A mixture of 67% Deposit A and 33% Carbon

• D: 49SiO2-25Al2O3-12.5CaO-12.5Fe2O3-1MgSO4 (liquid at 650 C)

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Gas Phase DetailsGas Prior

AirPrior Oxy

SH/RH Air

SH/RH Oxy

(FGD)

SH/RH Oxy (wo

FGD)

WW Air

WW Oxy

(FGD)

WW Oxy (wo

FGD)

WW Air

WW Oxy

(FGD)

WW Oxy (wo

FGD)

Oxidative Conditions

Oxidative Conditions

Oxidative Conditions

Reducing Conditions

N2 74.1 0 Bal 8 8 Bal 8 8 Bal 8 8

CO2 14.6 60.1 14 Bal Bal 14 Bal Bal 14 Bal Bal

CO 5 5 5

H2S 0.1 0.1 0.3

H2O 5 32.6 9 20 20 9 20 20 9 20 20

O2 6 2.5 2.5 2.5 2.5 2.5 2.5 2.5

SO2 0.3 0.9 0.3 0.3 0.9 0.3 0.3 0.9 0.2 0.2 0.6

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Fireside Corrosion—Prior Experiments •Temperature = 675 C (1247 F), ~ Superheater Fireside•Gas Linear Velocity = 6 cm/min (not meant to be representative of power plant gas velocities)•Synthetic ash mixtures:

Ash Mixture

Composition, weight %

Fe2O3 Na2SO4 K2SO4 Al2O3 SiO2 Calculated Base/Acid

A 31.67 2.5 2.5 31.67 31.67 0.52

B 30 5 5 30 30 0.54

No Ash

With Ash

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NETL Office of Research & DevelopmentOxy-combustion Efforts

Fundamental Properties• Combustion and Radiative Property Data

Integrated Pollutant Removal• Field tests of IPR system—Hammond, IN facility• Flame characteristics, analyses of ash and slag, GateCycle

modeling• Corrosion Issues (field tests and laboratory electrochemical tests)

Multi-Scale CFD Modeling • Advanced coal chemistry, gas mixtures, turbulence, burner

geometry, particle models• Simulations of REI/University of Utah facilities• Integration of water wall fireside corrosion models

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Flue Gas Purification

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Flue Gas Purification for Oxy-Combustion Air Products and Chemicals, Inc.

• CO2 may need to be cleaned of acidic impurities such as HCl and SO2 before being transported by pipeline for sequestration

• Feasibility of purifying CO2from oxy-combustion will be studied

1. SO2/NOx removal at 1-30 atmospheres pressure

2. Inert removal at 30-110 atmospheres pressure

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Rig Constructed

ReactorEntire Test Rig

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Range of Flue Gas Tested

• Low S bituminous oxy-combustion flue gas (WV)

Component Vol %

CO2 15 – 85

H2O 3 - 5

O2 3 - 5

N2 2 - 75

Ar 4 - 5

SO2 600 – 2600 (ppm)

NOX 125 – 400 (ppm)

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First Test Run Results

-100

0

100

200

300

400

500

600

700

20:38:24 20:52:48 21:07:12 21:21:36 21:36:00 21:50:24 22:04:48 22:19:12 22:33:36

ppm

v

Time

Oxyfuel 22 January 2010

[FLUGAS]NO.SCALED

[FLUGAS]SO2.SCALED

Condition DSOx Conversion >99%NOx conversion >90%(NOx zero +/- 20 ppmv)

Reactor Inlet Reactor Inlet Reactor Inlet Reactor Inlet

Reactor OutletReactor OutletReactor Outlet

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Second Campaign

• High S bituminous oxy-combustion flue gas (Illinois)• Test conducted to evaluate wider performance range

– SO2: 20 – 5930 ppm– NOx: 50 – 230 ppm– SO2/NOx ratio: 0.2 – 81

• Reactor performance repeatable – Similar capture rates under similar SOx/NOx ratios

• Hg removal observed at various stages of the process– Most removal in pre-scrubber sump

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Flue Gas Purification for Oxy-Combustion Praxair, Inc.

• Development of flue gas purification for oxy-combustion retrofits

• Targets:

– 99 percent SO2 and mercury removal

– >90 percent NOx removal

• Separate high and low S coal systems investigated

– Activated Carbon Bed

– Sulfuric Acid Process

– Both use VPSA for addt’l CO2 recovery

• O2, N2, Ar separated and vented

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Preliminary Results

• SO2 and NO are oxidized and retained on bed

• Dilute acid stream produced

• Performance better at lower Temp, higher Pressure

• Water aids in SO2removal

• >99% SO2 and >96% NOxremoval at 15 barg

• Performance maintained after 30 days testing at bench scale

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Techno-Economic Study Results

• FGD cannot be eliminated – identified by design team due to limits on pulverizers and boiler MOC. Alternate configuration to minimize:

• System removes 44 to 48% of SOx in FGD, rest in Praxair CPU

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To Find Out More About NETL’s CO2 Capture R&D:

http://www.netl.doe.gov/technologies/coalpower/ewr/index.htmlhttp://www.netl.doe.gov/technologies/coalpower/ewr/index.html