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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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2
2
4
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5
2
2
2
4
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5
2
2
2
4
4
4
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5
5
2
2
2
4
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5
5
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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
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