Hossein Ghezel-Ayagh (PI)
June 13, 2018
SOFC Development Update at FuelCell Energy
19th Annual Solid Oxide Fuel Cell (SOFC) Project Review Meeting Washington, DC
2
SOFC Technology Development & Deployment Roadmap
• Ongoing technology development and system field testing is laying the foundation for cost-competitive DG and centralized SOFC power systems
2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027
Year
MW-Class Demonstration
Utility-Scale (>100 MW) IGFC and NGFC Systems
50 kW System
Technology Development
30 kWStack Tower
10 kWStack
60 kWStack Module
200 kW System
Field Test
NG and Biogas Based DG Systems
IGFC/NGFC Systems
100 kW System Test
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Cell and Stack Technology Overview
• Cell: − Planar anode supported − 0.6 X 254 X 254 mm with 550 cm2
active area− Manufactured by tape casting,
screen printing and co-sintering• Stack:
− Ferritic stainless steel sheet Interconnect
− Compressive ceramic seal − Integrated manifolding with formed
flow field layers− 120 Cells in a standard stack with
16 kW output @ 160 A
4
Advances in Cell Technology:Redox Tolerance Improvement
Anode Mechanical
Property Improvement
Anode Microstructure Improvement
Cell Improvement
• A wide range of anode microstructures with enhanced mechanical properties were studied for improvements in redox tolerance
• Redox tolerance improved from 15% performance loss (baseline cell) down to 0.2% loss after 6 redox cycles with varying extent of nickel oxidation within the anode
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Accelerated Redox Tolerance Test Results
Multi-prong approaches were implemented to reduce anode strain upon Ni re-oxidation for achieving improvements in redox tolerance
• Redox cycle conditions designed for accelerated degradation:− Polarization curves to 0.74 A/cm2
− 10 thermal cycles red lines− 10 redox cycles green lines
• Accelerated tests showed:− Baseline TSC3 cell failed after
5 redox cycles− Recent cell with modified
anode structure is still running well after 10 redox cycle
Redox Cell
10 Redox Cycles
Baseline TSC3 Cell
Failed After 5 Redox Cycles
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Post-Redox Cycles Evaluation
• Standard cell (left) failed catastrophically after 5 redox cycles
• Autopsy showed broken cell with significant oxidation
• Modified redox tolerant cell (right) is fully intact
• Autopsy showed no sign of cracks and no oxidation in active area
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In-House Interconnect (IC) Coating• Studied both in-situ and ex-situ MCO applications
as protective layers for cathode interconnects• A 16 cell stack using baseline 550cm2 TSC3 cells
with alternating interconnect coatings was used to provide behavioral comparison of the two types of coatings
• Ex-situ MCO coatings provided better protection against Cr evaporation and lower performance degradation rate as compared to in-situ coatings
Sheet Metal
• PVD Co-Coating
Co-coated Sheet Metal
• IC Cutting and Forming
Co-coated IC
• Stack Assembly
MCO Coated IC
• MCO Formed In-Situ during Stack Operation
Sheet Metal
• IC Forming
IC• MCO Coating
Porous MCO
Coated IC
• Densification
Dense MCO
Coated IC
• Stack Assembly
Stack fabrication process using in-situ MCO IC coating
Stack fabrication process using ex-situ MCOIC coating
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Enhanced Cathode Performance Stability Using Atomic Layer Deposition (ALD)
ALD coated LSCF powders resulted in reduced cathode degradation rate
Sonata
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1
1.2
0 500 1000 1500 2000
Pote
ntia
l (V)
Time (hr)
Galvanostatic Hold @ 500 mA/cm2
ALD Coated LSCF Powder
Baseline LSCF
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-0.15
-0.1
-0.05
00 0.1 0.2 0.3 0.4 0.5 0.6
Z im
, Ω·c
m2
Zre, Ω·cm2
Nyquist PlotCoated-555 hr, 0.5 A/cm2Coated-1065 hr, 0.5 A/cm2Coated-1465 hr, 0.5 A/cm2Baseline-48 hr, 0.5 A/cm2Baseline-800 hr, 0.5 A/cm2
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00.1 10 1000 100000
Z im
, Ω·c
m2
Frequency
Bode PlotCoated-555 hr, 0.5 A/cm2Coated-1065 hr, 0.5 A/cm2Coated-1465 hr, 0.5 A/cm2Baseline-48 hr, 0.5 A/cm2Baseline-800 hr, 0.5 A/cm2
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80-Cell Stack Test
Cell Active Area: 550 cm2
Furnace Temperature: 690°C
Fuel: Simulated reformate, DIR= 36%, Uf = 68%
Oxidant: Air, Ua = 15%
Current: 160A (0.291 A/cm2)
Test in ProgressDegradation Rate: 0.4%/1000 hours for 11,700 hours
• Recent cell and stack design/manufacturing advances incorporated into 80-cell stack
• Ongoing testing at system conditions shows 0.4%/1000 hours degradation rate
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200 kW SOFC System
200 kW system is designed to validate stack reliability and scalability of stack-module design
Moderate temperature recycle loop to reduce cost and footprint while increasing reliability
SOFC Gross Power
DC Power 225.0 kW 244.0 kWEnergy & Water InputNatural Gas Fuel Flow 19.7 scfm 21.6 scfmFuel Energy (LHV) 323.2 kW 355.5 kWWater Consumption @ Full Power 0 gpm 0 gpmConsumed PowerAC Power Consumption 10.8 kW 12.5 kWInverter Loss 11.3 kW 12.2 kWTotal Parasitic Power Consumption 22.0 kW 24.7 kWNet Generation &Waste Heat AvailabilitySOFC Plant Net AC Output 203.0 kW 219.3 kW
Available Heat for CHP (to 48.9°C) 84.7 kW 90.8 kWExhaust Temperature - nominal 370 °C 370 °C
Efficiency
Electrical Efficiency (LHV) 62.8 % 61.7 %Total CHP Efficiency (LHV) to 48.9°C 89.0 % 87.2 %
200 kW SOFC System Performance SummaryNormal
Operating Conditions
Rated Power
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200kW SOFC Power System Layout
100kW SOFCIntegrated Modules
Cathode Air System
Fuel Desulfurizer
Integrated Anode Recycle System
EBoPInverter/Transformer
& Plant ControlsGas ControlsFuel and Purge
System Start-Up Water Treatment System
• Includes (2) 100kW SOFC stack modules designed to operate independently • Factory assembled & shipped as a standard ISO 20’ x 8’ container
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• Excellent stack to stack performance reproducibility
• Stacks for 200 kW system meet cell voltage criteria
• Stacks shipped to FCE Danbury, CT and integrated into 100 kW modules
200 kW System Stack Manufacturing
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100 kW Module Design & Fabrication
100 kW Stack Module Architecture:• Fully integrates all hot BoP equipment within the module• Eliminates high-temperature plant piping & valves• Reduces Cr evaporation protective coatings within plant/module • Integrated anode blower & module-specific instruments greatly decreases plant footprint
Removable Vessel Shell
I&C Panels
Cathode Process Air Connections
Anode Recycle System
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200 kW BoP Fabrication
Desulfurization Units
Start-up Water System
Skid Support-Integrated Piping
Air Delivery System
Process ControlSystem
Control Hardware Cabinet
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Stack Module Integration
Two 100-kW stack modules have been incorporated within the 200 kW system BoP, resulting in one transportable integrated system
200 kW Bop
100 kW Stack Module
100 kW Stack Module Integration
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200 kW SOFC System Factory Testing
200 kW system installed at FCE’s Danbury, CT Test Facility.
Factory Acceptance Testing is underway.
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Example of 100kW Stack Module Acceptance Test Results
Screen Shot of the Power Plant HMI
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200 kW System Demonstration Site Preparation
NRG Energy CenterPittsburgh, PA
• Permitting Process Complete• Site Preparation was completed
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Next Generation Stack Technology
PropertyCSA Stack Scale
CommentsShort Mid Full
Cell count 45 150 350
Fuel cell voltage, V 38 128 298 At 0.85 V/cell
Stack Power, kW 0.9 3.0 7.0 At 0.29 A/cm2
Height, mm (in)
91
(3.6)
211
(8.3)
440
(17.3)
Compact SOFC Architecture (CSA)
Full Height CSA Stack:
• 470 W/kg• 780 W/L
Baseline Large Area Stack (LAS):
• 76 W/kg• 185 W/L
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Example Fuel Cell Run 68%Uf 40%Ua 25% internal reforming, 0.3 A/cm2
CFD Model of CSA Stack
• Fully coupled CFD/electrochemical CSA stack model was developed– Full stack (lumped porous
body model)• High current operation and
complex geometry of CSA stack requires large number of calculations
• ANSYS HPC Pack licensing and cluster computing services were used to run the model
350-cell stackSelect cell layers shown
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Automated Work Cell for CSA Stack Fabrication
Current production rates achieved equivalent of up to 4 stacks per shift/day
Automated work cell commissioned for:• Stack builds• Cell and interconnect
QC
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CSA Stack Fabrication
• Initial stacks of new design (CSA Stack) has been built and tested in both fuel cell and electrolysis modes
In-stack thermocouples (4)
Current collector (+)
Voltage instrumentationleads
45-cellStack
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
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0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
Utili
zatio
n
Cell
Volta
ge (V
)
Elapsed time (hours)
45 Cell CSA , TS1
Average Cell 1-5
Average Cell 6-10
Average Cell 11-15
Average Cell 16-20
Average Cell 21-25
Average Cell 26-30
Average Cell 31-35
Average Cell 36-40
Average Cell 41-45
uf
ua
• Very strong utilization performance (>900 mV) at 80% fuel utilization at 0.25 A/cm2
– Demonstrates good flow distribution and even thermal conditions within the stack
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CSA Testing
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0 200 400 600 800 1000 1200 1400 1600 1800
Cell
Volta
ge (V
)
Elapsed time (hours)
GT060248-0007 TC1 FC Hold - 28/Mar/1845 cell CSATest stand 1
Average Cell 1-5
Average Cell 6-10
Average Cell 11-15
Average Cell 16-20
Average Cell 21-25
Average Cell 26-30
Average Cell 31-35
Average Cell 36-40
Average Cell 41-45
65% fuel utilization40% air utilization0.25 A/cm2
830 W output0.66 % /khr degradation
65% fuel utilization40% air utilization0.29 A/cm2
935 W output0.61 % /khr degradation
• Good performance and stability• Tight voltage spread shows good flow distribution• Aggressive thermal conditions (lower air flow, lower pressure drop)
Fuel composition:53% H244% N23% H2ONon-reforming surrogate gas
Stack -0007 exceeding 1600 hours at 830-935 W output (with >70% LHV efficiency)
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CSA Stack Factory Cost Estimate
CSA Stack Factory Cost Estimate as a Function of Production per Year
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Summary
Cell
• New redox tolerant cell stability was demonstrated after 10 redox cycles• ALD coated cathode materials showed improved endurance• In-house developed ex-situ MCO coating showed significant protection
against Cr poisoning
Stack• Baseline stack tested for >11000 hours showed <0.4%/kh degradation rate • 17 baseline stacks were fabricated for a 200 kW SOFC power plant• Initial trials of next generation CSA stacks have been successful
System
• 2 stack modules were built each with 8 stacks of 120 cells• Factory tests of the 200kW SOFC system was initiated• Preparation of the demonstration site for the 200kW SOFC system was
completed
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Acknowledgements
The progress in SOFC technology was supported by DOE/NETL Cooperative Agreements: DE-FE0011691, DE-FE0023186, DE-FE0026199, and DE-FE0026093
Guidance from NETL Management team: Shailesh Vora, Joseph Stoffa, Patcharin Burke, and Heather Quedenfeld