1) SECA Phase I Validation Testing2) Coal Gas Impurity Studies

Energy Systems Dynamics Division

National Energy Technology Laboratory

2007 SECA WorkshopAugust 7-9, 2007Dr. Randall Gemmen

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Projects for Review Today

• 1) DOE Fuel Cell Test Facility− Independent Testing for

SECA Program

• 2) Coal Contaminant Investigations− Focused Studies Using

Specific Contaminants− Direct Coal Syngas Studies

1) DOE Fuel Cell Test Facility

ObjectivesSupport DOE’s SECA Program by providing independent test and evaluation of its sponsored partner’s SOFC fuel cell systems (each done separately)

ChallengesAccurately measuring the critical performance parameters

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ApproachDefine test facility requirements based on SECA Industry Team SOFC unit specificationsApply relevant industry test standards− PTC 50-2002

• Performance analysis standards• Error analysis standards

Base-Design by Concurrent Technologies CompanyPhased construction through 2010

Natural Gas/Methane (2006)Synthesis Gas for Coal-Based FC (ca. 2008-20010)

Measurement Methodology− Gemmen & Johnson (2006), “Evaluation of Fuel Cell System

Efficiency and Degradation at Development and During Commercialization” J. Power Sources.

SECA prototype evaluations− Shake-down testing (Acumentrics unit)− Evaluate prototype systems− Report results to SECA management

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Instrumentation• 0-12kW AC and DC load banks and load profile controller• Continuous power measurement

− Aux Input: real power, power factor, frequency− AC: real power, power factor, frequency

• Revenue quality meter (kW-hr)• Solid state metering (watt/var/pf/freq)

− DC: power• Continuous fuel measurement

− High accuracy corriolis meter− On-line GC for fuel energy− Revenue quality meter

• Safety instrumentation• Safety communication• Exhaust gas analysis• On-line UPS system• Vent hood• Purge gas• DI-water• Spare I/O capability

UPSUPS

hood

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Power Quality Interface

DC Load Bank

AC Load Bank

AC Metering

DC Metering

Aux Metering

Fuel Rack

Fume Hood

DOE Fuel Cell Test Facility

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Control Room

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Procedure

• Begin close coordination with fuel cell developer• Communicate all detailed test unit requirements and

facility capability/limitations• Account for critical safety requirements on both sides• Perform engineering documentation updates and

facility modifications• Install test unit• Perform all critical equipment calibrations• Startup test unit, and perform operational checkout• Initiate test plan• Complete test plan and shutdown test unit• Perform post-calibrations on all critical equipment• Analyze and report test results to SECA Mgmt.

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Units Tested

• overall efficiency > 35% stationary

• degradation <2%/500 hr

• peak power

Delphi

FCE/VPS

Acumentrics

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Degradation Measurement

SV = variance of the measured slope (degradation).σ = standard error of measurement value.ti = time value for data point ‘i’.0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 0.01 0.02 0.03 0.04 0.05

Noise Level of Efficiency Measurement (σ) [1]

Min

imum

Tes

t Dur

atio

n [h

r] --

R

egre

ssio

n M

etho

d

0

5000

10000

15000

20000

25000

Min

imum

Tes

t Dur

atio

n [h

r] --

Tw

o Po

int M

etho

d

Expected Degradation Rate = 1%/1000hr

Std. Error of Measured Degradation Rate=10%

Standard Error of Measured Degradation Rate=25%

Standard Error of Measured Degradation Rate=25%

Typ. Spread in Measurement Error

From Regression:

SVσ

2

1

N

i

ti( )2∑=

1

N

i

ti∑=

⎛⎜⎜⎝

⎞⎟⎟⎠

2

N−

From 2-Point (end-start):

SV 2 σ2

⋅

What length of time must test run to assess the degradation rate to within a certain X% accuracy?

0.93

0.95

0.97

0.99

1.01

0.00 0.50 1.00Time [1000 hr]

Nor

mal

ized

Ef

ficie

ncy

[1]

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Results

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Summary

• Government programs need to measure progress in meeting goals…SECA has accomplished this through independent test and evaluation of developer technology−Three SECA units tested−Results show performance meeting SECA Program

objectives

• Future: − Transform facility to support evolving SECA Coal-based

Program.

2) Coal Contaminant Investigations

Kirk Gerdes, Jason Trembly, Randall Gemmen

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Objectives

• Objectives− Determine the effect of trace coal syngas species on the

performance of solid oxide fuel cells• Challenges

− Little research has been completed investigating behavior of SOFCs operating on coal syngas

− Many possible interactions between trace species contained in coal and SOFC materials

− Coal contains many trace species so a very large effort will be required to screen the affect of all of the contaminants

•present in coal syngas

•present in coal syngas;•not removed by warm-gas cleanup

•present in coal syngas;•not removed by warm-gas cleanup;•potential reaction with anode

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Approach

• Thermodynamic studies−Warm/hot gas cleanup system/trace specie interactions−Gaseous trace specie/SOFC anode interactions

• Electrode transport modeling−Dust Gas Model (DGM)−Mean Transport Pore Model (MTPM)

• Experimental study of individual trace species on SOFC performance−HCl, H2S, AsH3, PH3, H2Se− Syngas (Kivisaari et al.): 29.3%H2, 28.7% CO, 11.8% CO2, 27.2% H2O, 3% N2

• Experimental study on direct coal syngas

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Effect of Trace Species on SOFC Anode

• Affect the ability of Ni to promote the electrochemical reactions− Trace species on Ni surface inhibit the adsorption of

H2, CO, or dissociation of H2

• Affect the ability of YSZ to transport oxygen ion− Formation of secondary zirconia phases

• Affect the electrical conductivity− Formation of secondary nickel phases such as nickel-

phosphide

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900 °C

700 °C

Experimental Methodology

• Anode supported SOFCs with Ni/YSZ anodes operated between 750-800ºC

• Cells operated with simulated coal syngas containing single trace specie of interest

• VI scans and EIS methods used during testing• Post trial SEM, EDS, and XRD used

Ca—Pt Mesh/Paste; An—Ni Mesh/Paste

PermeationTube

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Warm Gas Cleanup(Thermodynamic Predictions—FactSage. v. 5.4)

0.26

0.15

0.025

0.0110.071.910.6

Concentration After Cleanup

ppmv

SolidZnGas/SolidPb

SolidVSolidNa

Gas/SolidSeSolidKGasHgSolidCrSolidBe

Gas/SolidCdGasSb

Gas/SolidPGas/SolidAs

Behavior Component

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Anode Interactions(Thermodynamic Predictions—FactSage v. 5.4)

Equilibrium Pressures of AsH3 Associated with Equation 1 Over SOFC Operation Conditions at the Inlet (a) and Outlet (b).

( ) ( ) ( ) ( ) Eq.1g1.5HsNiAssNigAsH 23 +→+

0.E+00

5.E-07

1.E-06

2.E-06

2.E-06

3.E-06

3.E-06

4.E-06

4.E-06

700 750 800 850 900

Temperature [°C]

AsH

3 Equ

ilibr

ium

Pre

ssur

e [a

tm]

1atm

5atm

10atm

15atm

a)

0.E+00

5.E-08

1.E-07

2.E-07

2.E-07

3.E-07

700 750 800 850 900

Temperature [°C]A

sH3 E

quili

briu

m P

ress

ure

[atm

]

1atm

5atm

10atm

15atm

b)

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Summary of Anode Interactions(Thermodynamic Predictions)

• Species passing through warm gas cleanup:−Sb, As, Cd, Pb, Hg, P, Se

• At the maximum level of trace specie concentration entering the anode, the potentially anode reactive species are:−Sb, As, P

• (Other species may still impact cell performance through reaction at the surface; e.g., S.)

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Results: H2Se Testing

Figure 5. SOFC Power Density Operating at 750and 800 °C at 0.25 Acm-2 Over Time with 5 ppm H2Se.

0.00

0.05

0.10

0.15

0.20

0.25

0 20 40 60 80 100 120

Time [hrs]

Pow

erD

ensi

ty[W

/cm

2 ]

750 C800 C

Injection of5 ppm H2Se

0

200

400

600

800

1000

1200

1400

1600

20 30 40 50 60 70

2-Theta [deg]

Inte

nsity

[Cou

nts]

(1) (1)(2) (2) (2) (2)(2)

(1) Ni(2) YSZ

thermodynamic calcs. show no tendency toward forming secondary Ni phase

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Results: Arsine Testing

SOFC Power Density and XRD Spectra Operating at 800 °C and 0.25 Acm-2 Over Time with AsH3 Concentration of 0.1 ppm.

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 100 200 300 400 500 600 700 800Time [hrs]

Pow

er D

ensi

ty [W

/cm

2 ]

0

1000

2000

3000

4000

5000

20 25 30 35 40 45 50 55 60 65 70

2-Theta [deg]

Inte

nsity

[Cou

nts]

(1) (1)(2) (2)(2)(2)

(3) (3)

Deg. Rate = 8.9%/1000hr +/- 0.6%

(1) Ni(2) YSZ(3) NiAs

( ) ( ) ( ) ( )g1.5HsNiAssNigAsH 23 +→+

SOFC Operation on Direct Syngas

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PSDF Process Flow Diagram

M

AirSteamOxygen

Pressure Letdown Valve

Gasification Ash

Gasification Ash

Sorbent

TransportGasifier

Disengager

CycloneParticulate

ControlDevice

Screw Cooler

rtupner

Air

Loop Seal

PrimaryGas Cooler

SecondaryGas Cooler

CFAD

Cold Gas CleanupHot Gas

Cleanup

SandFeeder Slip Stream Test Unit

To Atmospheric Syngas Combustor

ContaminantInjector

Air

Piloted SyngasBurner

Flue GasCombustion

Turbine

To Fuel Cell

M

GasifierAeration

1600°F (871°C)

700-800°F (371-427°C)

600-700°F (315-371°C)

500-600°F (260-315°C)

100-600°F (38-315°C)controllable

Warm GasCleanup

M

AirSteamOxygen

Pressure Letdown Valve

Gasification Ash

Gasification Ash

Sorbent

TransportGasifier

Disengager

CycloneParticulate

ControlDevice

Screw Cooler

rtupner

Air

Loop Seal

PrimaryGas Cooler

SecondaryGas Cooler

CFAD

Cold Gas CleanupHot Gas

Cleanup

SandFeeder Slip Stream Test Unit

To Atmospheric Syngas Combustor

ContaminantInjector

Air

Piloted SyngasBurner

Flue GasCombustion

Turbine

To Fuel Cell

M

GasifierAeration

1600°F (871°C)

700-800°F (371-427°C)

600-700°F (315-371°C)

500-600°F (260-315°C)

100-600°F (38-315°C)controllable

M

AirSteamOxygen

Pressure Letdown Valve

Gasification Ash

Gasification Ash

Sorbent

TransportGasifier

Disengager

CycloneParticulate

ControlDevice

Screw Cooler

rtupner

Air

Loop Seal

PrimaryGas Cooler

SecondaryGas Cooler

CFAD

Cold Gas CleanupHot Gas

Cleanup

SandFeeder Slip Stream Test Unit

To Atmospheric Syngas Combustor

ContaminantInjector

Air

Piloted SyngasBurner

Flue GasCombustion

Turbine

To Fuel Cell

M

GasifierAeration

1600°F (871°C)

700-800°F (371-427°C)

600-700°F (315-371°C)

500-600°F (260-315°C)

100-600°F (38-315°C)controllable

Warm GasCleanup

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Test RigMulti-cell Array

• Permits parallel operation of 12 button cells

• Divided into 4 channels of 3 cells each• Improves testing method

− Rapid collection of repeat data− Reduces systematic experimental error

• Reduces sources of contamination− Seals− Materials

• Status− Final design completed− Rig construction underway− Shakedown testing by Oct.− Field testing in Jan., 2008

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Summary

Contributions to program

• Performance of SECA Phase I units validated

• Effect of trace species on SOFC performance being quantitatively assessed via focused specie evaluation and direct syngas testing

• Obtaining improved measurements of gas phase contaminant concentrations (GC/ICP/MS) in coal gasification derived syngas

• Development of MCA accelerates all SOFC testing, particularly in materials and components areas