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OPERATION OF THE PSDF TRANSPORT GASIFIER

Session: New DevelopmentsGasification Technologies 2002

October 30, 2002

Peter V. Smith Kellogg Brown & Root, Inc. (KBR)

Brandon M. DavisP. Vimalchand

Guohai Liu Southern Company Services

James Longanbach National Energy Technology Laboratory

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What Is The PSDF?

The PSDF is a joint-DOE/industry research facility

where advanced power systems can be tested in an

integrated environment at a scale sufficient to provide

confidence and data for commercial design.

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Power Systems Development Facility Program Objective

Develop advanced coal-based power generation

technologies that can produce electricity at

competitive cost while meeting all environmental

standards and support Vision 21.

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PSDF Participants•U.S. Department of Energy - National Energy Technology Laboratory •Southern Company•KBR•Siemens-Westinghouse•Electric Power Research Institute•Peabody Holding Company•Southern Research Institute

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America’s Advanced Coal Research Center

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Transport Reactor SystemCoalSorbent

AirSteam

Ash

Flue Gas

airSyngas Combustor

Baghouse

Stack

Pressure LetdownGas Cooler

Recycle Gas

cooling

N2 or Air

cooling

cooling

Ash

Ash Hopper

cooling

AFBC

cooling

Screw Cooler

AshLockhoppers

TransportReactor

Disengager

StartupBurner

Cyclone

Gas Cooler

Lockhoppers

Char/Ash

Siemens -Westinghouse PCD

Gas Cooler

Air

ScrewCooler

ScrewCooler

AirSteamOxygen

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Transport Reactor

Sorbent

AirSteam

Coal

MixingZone

Riser

Disengager To PrimaryGas Cooler

Loopseal

Cyclone

Standpipe

J-leg

StartupBurner

(propane)

AirOxygenSteam

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CoalSorbent

Air

ProcessGas

SpentSolids

Advantages of Pressurized Transport Reactor

•Excellent Gas-Solids Contact.

•Low Mass Transfer Resistance between Gas and Solids.

•Highly Turbulent Atmosphere

•High-coal throughput

•High Heat release

•Designed without expansion joints

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Loop Seal Modification

Original Design

ModifiedAreas

Loop SealLayout

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Lower Mixing Zone Modification

Replaced

•Existing piping unsuitable for oxygen •Test different method for distributing steam and oxygen•No internals in design

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Lower Mixing Zone ModificationOxygen Blown Design

4 O2 + H2O Nozzles

N2

Steam

O2

N2Air

O2 + H2O

4 H2O Nozzles

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Gasification Summary

309Air & Oxygen

Bituminous HiawathaSeptember 2002TC09

442AirPRBAlabama Bituminous

January – April 2002

TC07

364Air & Oxygen

PRBJune 2002TC08

1025AirPRBJuly –September 2001

TC06242AirPRBMarch 2001GCT4183AirPRBJanuary 2001GCT3217AirPRBApril 2000GCT2

233AirPRBAlabama BituminousIllinois #6

September –December 1999

GCT1HoursModeFuelsDatesTest Run

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Coal PropertiesPRB Hiawatha

Moisture, wt% 20.93 9.80Carbon, wt% 57.02 64.70Hydrogen, wt% 3.74 4.40Nitrogen, wt% 0.66 1.10Sulfur, wt% 0.26 0.37Ash, wt% 5.23 8.50Volatiles, wt% 37.39 35.90Fixed Carbon, wt% 36.46 45.80Higher Heating Value, Btu/lb 9,391 11,400Lower Heating Value, Btu/lb 8,828 10,891CaO, wt % 1.27 1.11Ca/S, mole/mole 2.83 1.67

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Typical Operating Conditions

Fuel Type Powder River Basin, Alabama Calumet Bituminous, Hiawatha.

Fuel Particle Size (mmd), µm 200 - 350 Average Fuel Feed Rate, pph 2,700 - 5,000Sorbent Type Ohio Bucyrus limestoneSorbent Particle Size (mmd), µm 10 - 30 Sorbent Feed Rate, pph 0 - 200 Reactor Temperature, °F 1670 - 1850Reactor Pressure, psig 140 - 270 Riser Gas Velocity, fps 40 – 60Riser Mass Flux, lb/s·ft2 150 - 700 Synthesis Gas Flowrate, pph 15,000 - 30,000 Air/coal ratio 2.5 – 3.5Steam/coal mass ratio 0.0 to 1.0

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Lower Heating Value

( ) ( )( ) ( ) 100/

%C1641%CH913

CO%322%H275F)LHV(Btu/SC

24

2

×+×

+×+×=

+

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Per Cent Oxygen Fed

22

222 OPureNPureSteamAir

OPureOAirO%+++

+=

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Raw LHV

0

20

40

60

80

100

120

8 9 10 11 12 13 14 15 16 17 18 19 20 21

Overall O2 in Feed Gas, %

Low

er H

eatin

g V

alue

, Btu

/SC

F

PRB Air blownPRB Oxygen BlownHiawatha Air BlownHiawatha Oxygen Blown

Overall % O2 in Feed GasEffect on Raw LHV

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Nitrogen Correction• Remove aeration & instrument nitrogen

– Commercial design will use recycle gas– Does not change Water Gas Shift

• Remove heat (coal) required to heat extra nitrogen– Removes N2, CO2, & H2O– Changes Water Gas Shift

• Adiabatic correction – Removes heat (coal) lost by reactor

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Corrected LHV

0

50

100

150

200

250

10 15 20 25 30 35 40 45Overall O2 in Feed Gas, %

Low

er H

eatin

g V

alue

, Btu

/SC

F

PRB Air BlownPRB Oxygen BlownHiawatha Air BlownHiawatha Oxygen Blown

N2 Corrected LHV Overall % O2 in Feed Gas

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Carbon Conversion

The per cent of fuel carbon that is converted to gaseous carbon- CO2, CO, CH4, C2

+.

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Carbon Conversion

50

55

60

65

70

75

80

85

90

95

100

1,660 1,680 1,700 1,720 1,740 1,760 1,780 1,800 1,820 1,840 1,860Riser Temperature, F

Car

bon

Con

vers

ion,

%

Powder River Basin

Hiawatha Bituminous

Riser TemperatureEffect on Carbon Conversion

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Reactor Inventory Change

0

10

20

30

40

50

60

70

80

90

100

0 200 400 600 800 1,000Run Time, hours

Wei

ght %

SiO2

CaO

Al2O3

TC06 - PRB CoalStandpipe SiO2, CaO, & Al2O3

4 Week Break7/25/01 to 8/20/01

Bed Material Replaced

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H2S Capture - Theory

23 COCaOCaCO +↔

2232 COOHCaSCaCOSH ++↔+

OHCaSCaOSH 22 +↔+

OSH

OOH

22

2

PP

K = OSH

OCO

OOH

22

22

PPP

K =oCO1 2

PK =

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Equilibrium H2S

0

100

200

300

400

500

600

1,400 1,500 1,600 1,700 1,800 1,900 2,000Temperature, F

H2S

Con

cent

ratio

n, p

pm

Measured Sulfur emissions

Maximum Sulfur emissions

CaOCaCO3

TC06-32H2S-CO2-H2O-

CaCO3-CaO-CaSEquilibrium

Equilibrium H2S Concentration

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PRB Sulfur Emissions

0

100

200

300

400

500

600

700

0 100 200 300 400 500 600 700Measured Total Reduced Sulfur, ppm

Equi

libriu

m H

2S, p

pm

PRB - Sorbent AddedPRB - No Sorbent Added45 Degree Line

Total Reduced Sulfur Emissions &Equilibrium H2S - PRB Coal

Data taken at start of run

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TC08 Sulfur Emissions

0

100

200

300

400

500

600

700

0 50 100 150 200 250 300 350 400Run Time, hrs

TRS

or E

quili

briu

m H

2S, p

pm

0

2

4

6

8

10

12

14

Stan

dpip

e C

aO, w

t%

Measured TRSEquilibrium H2SStandpipe CaO

Unit tripped,sand added

Unit tripped,sand added

TC08 - PRB Coal, No Sorbent Added

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Hiawatha Sulfur Emissions

0

100

200

300

400500

600

700

800900

1,000

0 50 100 150 200 250 300 350Run Time - Hours

TRS

or H

2S, p

pm

TRS EmissionMax Coal TRSEQM H2S

TC09 Hiawatha Bituminous

Sulfur EmissionsOutage

O2 - Blown

Outage

No Sorbent Added

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Future Plans• Connect Transport Reactor to Combustion

Turbine• Test Other Coals, Petroleum Coke• Test Improved Coal Feeder• Commission Recycle Gas System• Demonstrate Hot Gas Emissions Control

Techniques

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Conclusions•Met commercial goals for gas heating values and carbon conversions for subbituminous PRB coal. •Hiawatha bituminous coal was successfully gasified in air and oxygen blown mode.•Hiawatha gas heating values consistent with PRB, but Hiawatha carbon conversions lower than PRB•Sulfur emissions were as predicted from thermodynamic equilibrium at low sulfur emissions when injecting limestone. •The Powder River Basin coal ash alkalinity was nearly sufficient to remove the equilibrium amount of synthesis gas sulfur. •The oxygen delivery and new lower mixing zone operated well, permitting stable Transport reactor operation on both enriched air and full oxygen-blown service.