development of a novel efficient solid-oxide hybrid for co ... · development of a novel efficient...
Post on 02-Aug-2020
3 Views
Preview:
TRANSCRIPT
1Materials and Systems Research, Inc.
Development of a Novel Efficient SolidDevelopment of a Novel Efficient Solid--Oxide Hybrid Oxide Hybrid for Cofor Co--generation of Hydrogen and Electricity Using generation of Hydrogen and Electricity Using
Nearby Resources for Local ApplicationNearby Resources for Local Application
Greg Tao, Mike Homel, Bruce Butler, and Anil Virkar
Materials & Systems Research Inc., Salt Lake City, UT
2008 DOE Hydrogen Program Annual ReviewJune 11, 2008
Project ID#: PDP 33
This presentation does not contain any proprietary, confidential, or otherwise restricted information
2Materials and Systems Research, Inc.
OverviewOverview
• Project started: 02/10/2006• Project ends: 07/31/2009• Percent completed: 70%
• Total budget funding– DOE $2,480k– Contractor $ 620k
• Funding received in FY07– $ 1,265k
• Funding for FY08– $ 755k
Hydrogen generation by water electrolysis• G – Capital cost
– Low-cost, durable high-temperature materials development
– Lower operating temperature• H – System Efficiency• K – Electricity costs
• University of Alaska Fairbanks – anode supports fracture mechanisms and modeling of residual stresses (S. Bandopadhyay; N. Thangamani)
• University of Missouri-Rolla – cathode & seal materials development (H. Anderson; R. Brow)
• University of Utah – interconnect development (A. Virkar)
Timeline
Budget
Barriers
Partners
3Materials and Systems Research, Inc.
ObjectiveObjectiveOverall Objective
• To develop a low-cost and highly efficient 5 kW SOFC-SOFEC hybrid system co-generating both electricity and hydrogen to achieve the cost target of < $3.00/gge when modeled with a 1500 gge/day hydrogen production rate. • The project focuses on materials R&D, stack design & fabrication, and system design & verification.
2007 • 5 kW SOFC-SOFEC hybrid system development─ Materials development and application (electrodes & seals)─ Stack design and development─ Hybrid system design─ BOP components design and development
2008 • 5 kW SOFC-SOFEC hybrid system fabrication and assembly─ Cell & non-cell repeat units fabrication─ BOP components fabrication─ Stack assembly and integration─ Hybrid module evaluation─ Control system assembly & programming
4Materials and Systems Research, Inc.
MilestonesMilestonesQuarters, FY Milestone or Go/No-Go Decision1st Quarter, FY07
Go/No-Go decision: assess the appropriate load and strains that SOFC-SOFEC can withstand.
2nd Quarter, FY07
Go/No-Go decision: assess the viability of 1 kW hybrid module for cogeneration based on performance.
4th Quarter, FY07
Go/No-Go decision: finalize the cathode system for hybrid application.
3rd Quarter, FY08
Milestone: Complete the high temperature flexural tests and creep studies of SOFEC anode substrates.
4th Quarter, FY07
Milestone: Complete the design of the 5 kW system and major BOP components. Down select two “invert” glass compositions from 81 compositions that are thermal-mechanically compatible and thermal-chemically stable. Finalize the cathode system for SOFEC applications.
4th Quarter, FY08
Milestone: Complete fabrication of all cell/non-cell repeat units. Complete fabrication and pre-test of BOP components. Transfer the glass seal technology from the subcontractor to MSRI.
5Materials and Systems Research, Inc.
ApproachApproach
MSRI, UMR MSRI, UAF, UMR, UU MSRI, UU, UMR
Succ
ess
Cell / Stack /System DesignA. Stack design
B. 5kW system design
C. BOP design/dev.
D. Stresses analyses
E. Seals application
F. Economic analysis
Experimental VerificationA. Short stacks in dif. modes
B. 1 kW hybrid stack
C. Durability evaluation
D. BOP design & evaluation
E. 5 kW hybrid system development & evaluation
MaterialsDevelopmentA. Cathode materials Dev.
B. Anode optimization
C. Electrolyte optimization
D. Catalyst studies
E. Seals development
F. Fabrication Q.A.
80% complete 80% complete 50% complete
Thermocouple
Voltage leads
Thermocouple
Voltage leads
1-2 kW Stack(100 cm2/cell)
6Materials and Systems Research, Inc.
BackgroundBackgroundA Solid Oxide Fuel-Assisted Electrolysis Cell (SOFEC) directly applies the energy of a chemical fuel to replace the external electrical energy required to produce hydrogen from water/steam; decreasing the cost of energy relative to a traditional electrolysis process.
Fossil Energy / Renewable Energy
Electricity
Electrolyzer
Hydrogen Production
SOFEC + SOFC
Electricity
Unique process
0
50
100
150
200
250
300
350
0 200 400 600 800 1000 1200 1400
Temperature (K)
ΔH
, ΔG
, TΔs
(kJ/
mol
)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
VN
erns
t (V)
ΔH
TΔs
ΔG V Nernst
ΔHΔGV ocv
Electricity from GridCo-generationCH4-assisted SOFEC Reaction Electrochemical Process
4H2O + 8e’ 4H2 + 4O2- at cathode4O2- + CH4 CO2 + 2H2O + 8e’ at anodeCH4 + 2H2O CO2 +4H2Pure H2 formed. No need for H2 separation membranes. Lower electricity requirement.
7Materials and Systems Research, Inc.
Concept of Hybrid SOFCConcept of Hybrid SOFC--SOFEC Integral SystemSOFEC Integral System
• Pure H2 & electricity co-production from feedstock: hydrocarbon fuel, steam, and air
• Hybrid comprised of SOFCs and SOFECs
• SOFECs produce pure H2 and SOFCs generate electricity for a high H2 production rate
• Thermal integration improves system efficiency
Technical Challenges and SolutionsCost of Hydrogen
SOFC-SOFECperformance
Systemefficiency
Long-termdurability
cathode materials:composition,microstructure,catalyticcharacterisitcs;anode material:porosity, tortuosity,composition;low operatingtemperature:inexpensivematerials, non-precious metalcatalysts;manufacturability.
SOFC-SOFEChybridarchitecture;thermalintegration;co-generationconcept.
"invert" seal materialthermalmechanicalcompatibility andthermalchemicalstability;anode mechanicalstrength.
8Materials and Systems Research, Inc.
SOFEC Cathode Materials Development SOFEC Cathode Materials Development LSCM Redox Stability StudyLSCM Redox Stability Study
0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.20.0
-0.2
-0.4
-0.6
-0.8
-1.0
-1.2
Z"
Z'
1st (air/wetH2) at 800oC
2nd (air/wetH2) at 800oC
3rd (air/wetH2) at 800oC
4th (air/wetH2) at 800oC
5th (air/wetH2) at 800oC
6th (air/wetH2) at 800oC
• Previous studies show that (La,Sr)(Cr,Mn)O3-based cathode material is electrocatalytically and chemically stable in both reducing and oxidizing atmospheres
• Previous long-term tests show degradation rate < 1% per 1000hrs over a 4500 hrs continuous test in the SOFC mode.
• Redox stability is desired for reversible applications
9Materials and Systems Research, Inc.
SOFCSOFC--SOFEC Anode Substrate Development SOFEC Anode Substrate Development
NiO-YSZ
Reduction
• Fracture Mechanism• Reliability• Optimization of processing conditions
Microstructure and porosity studiesNi-YSZ
Effect of porosity, composition, temperature and thermal shock on Young’s Modulus, biaxial strength
and toughness in reducing environments at High TemperatureCharacterization
Effects of Residual/Chemical/Applied Stresses on Mechanical IntegrityEffects of Residual/Chemical/Applied Stresses on Mechanical Integrity
10Materials and Systems Research, Inc.
Reduction of HalfReduction of Half--cells cells
8YSZ
Ni
pore
8YSZNiO
• Porosity
• Triple phase boundary (TPB)
Unreduced
Reduced
NiO (s) + H2 (g) Ni (s) + H2O (g)
• Density
• Mechanical properties
Reduced
Unreduced
11Materials and Systems Research, Inc.
Effect of Reduction on Phases & MicrostructureEffect of Reduction on Phases & Microstructure
As-sintered 10min 30min 2 hr 8 hr
0 100 200 300 400 5000
10
20
30
40
50 Porosity Density
Time of reduction (min)
Por
osity
(%)
4.6
4.8
5.0
5.2
5.4
5.6
20 40 60 80 100
Inte
nsity
Diffraction angle 2θ (degree)
(111) YSZ
(200
) YS
Z
(111) Ni
(111
) NiO
(220
) YS
Z(2
00) N
i
(200
) NiO
(311
) YS
Z(2
20) N
iO(2
22) Y
SZ
(222
) YS
Z
(400
) YS
Z(3
11) N
iO(2
20) N
i(2
22) N
iO(3
31) Y
SZ
(420
) YSZ
(311
) Ni
(422
) YS
Z
(222
) Ni
As received NiO-8YSZ
10 min
30 min
2 h
8 h
NiNiO
10 min
30 min
2 h
8 h
As-sintered NiO-YSZ
20 40 60 80 100
Inte
nsity
Diffraction angle 2θ (degree)
(111) YSZ
(200
) YS
Z
(111) Ni
(111
) NiO
(220
) YS
Z(2
00) N
i
(200
) NiO
(311
) YS
Z(2
20) N
iO(2
22) Y
SZ
(222
) YS
Z
(400
) YS
Z(3
11) N
iO(2
20) N
i(2
22) N
iO(3
31) Y
SZ
(420
) YSZ
(311
) Ni
(422
) YS
Z
(222
) Ni
As received NiO-8YSZ
10 min
30 min
2 h
8 h
NiNiO
20 40 60 80 100
Inte
nsity
Diffraction angle 2θ (degree)
(111) YSZ
(200
) YS
Z
(111) Ni
(111
) NiO
(220
) YS
Z(2
00) N
i
(200
) NiO
(311
) YS
Z(2
20) N
iO(2
22) Y
SZ
(222
) YS
Z
(400
) YS
Z(3
11) N
iO(2
20) N
i(2
22) N
iO(3
31) Y
SZ
(420
) YSZ
(311
) Ni
(422
) YS
Z
(222
) Ni
As received NiO-8YSZ
10 min
30 min
2 h
8 h
20 40 60 80 100
Inte
nsity
Diffraction angle 2θ (degree)
(111) YSZ
(200
) YS
Z
(111) Ni
(111
) NiO
(220
) YS
Z(2
00) N
i
(200
) NiO
(311
) YS
Z(2
20) N
iO(2
22) Y
SZ
(222
) YS
Z
(400
) YS
Z(3
11) N
iO(2
20) N
i(2
22) N
iO(3
31) Y
SZ
(420
) YSZ
(311
) Ni
(422
) YS
Z
(222
) Ni
As received NiO-8YSZ
10 min
30 min
2 h
8 h
NiNiO
10 min
30 min
2 h
8 h
As-sintered NiO-YSZ
12Materials and Systems Research, Inc.
Effect of Reduction on Mechanical PropertiesEffect of Reduction on Mechanical Properties
0 200 400 600 800 100040
60
80
100
120
140
You
ng's
Mod
ulus
(GP
a)
Temperature (oC)
As-sintered 10min 30min 2h 8h
600 μm thick half-cells
0 200 400 600 800 100030
40
50
60
70
80Ni-8YSZ half cell in 5% H2-Ar atmosphere (600 μm)
You
ng's
Mod
ulus
(GP
a)Temperature (oC)
Half-cells that have NiO:
• Higher initial E and a peak in E at 300°C due to rhombohedral to cubic transition
Half-cells that have no or negligible NiO:
• No structural transition assisted change in E; Oxidation of Ni increases E
• Scattering of E at high temperatures due to thermodynamic instability of c-ZrO2
13Materials and Systems Research, Inc.
Events Affecting ‘E’ at Elevated TemperaturesEvents Affecting ‘E’ at Elevated Temperatures
200 400 600 800 1000-40
-20
0
20
40
60
80
100 As-sintered & reduced NiO-8YSZ half cells
Hea
t Flo
w
Temperature (OC)
As-sintered 10 min 30 min 2 hrs 8 hrs
Structural transition of NiO
Oxidation of Ni
0 200 400 600 800 10004
6
8
10
12
14
16 TEC of NiO-8YSZ Thermal Expansion
0 100 200 300 4000
10
20
30
40
50
60
Heating
Ther
mal
Exp
ansi
on (μ
m)
Temperature (OC)
Cooling
Temperature (OC)TE
C x
10-6
K-1
0.000
0.002
0.004
0.006
0.008
0.010
0.012
0.014
0.016
DL/L
O
0 200 400 600 800 10004
6
8
10
12
14
16 TEC of NiO-8YSZ Thermal Expansion
0 100 200 300 4000
10
20
30
40
50
60
Heating
Ther
mal
Exp
ansi
on (μ
m)
Temperature (OC)
Cooling
Temperature (OC)TE
C x
10-6
K-1
0.000
0.002
0.004
0.006
0.008
0.010
0.012
0.014
0.016
DL/L
O
• Rhombohedral to cubic transition of NiO that affects the thermal expansion and Young’s modulus @ ~ 300°C
• Oxidation of Ni @ ~ 500°C
14Materials and Systems Research, Inc.
Hermetic Seals Development Hermetic Seals Development
“Invert” silicate:Glasses with SiO2<45 mole%
Compositions based on:Pyrosilicate and Orthosilicate
Evaluated More Than 81 ‘Invert’ Glass CompositionsEvaluated More Than 81 ‘Invert’ Glass CompositionsEvaluated More Than 81 ‘Invert’ Glass Compositions
650 700 750 800 850 9006
8
10
12
14
YSZ
430SS
G#81
G#50
Coe
f. Th
erm
al E
xpan
sion
(10-6
/ o C)
Softening temperature ( oC )
15Materials and Systems Research, Inc.
Electrical Conductivity in Air and Forming GasElectrical Conductivity in Air and Forming Gas
0 5 1 0 1 5 2 0 2 5 3 0 3 5
-7 .0
-6 .8
-6 .6
-6 .4
-6 .2
-6 .0
-5 .8
5 0 S iO 2-3 0 B a O -2 0 Z n O
Con
duct
ivity
log(
S/cm
), in
air
t im e (d ays )
DC
430SS substrates
Glass pasteTest conditions:800oC in air and forming gas
Glass #50
0 1 2 2 4 3 6 4 8-8 .0
-7 .5
-7 .0
-6 .5
-6 .0
F o rm in g g a s
A ir
'A s s e a le d G # 8 1 ' a t 8 0 0 oC
Con
dutc
ivity
log
(S/c
m)
t im e (h rs )
16Materials and Systems Research, Inc.
Thermal Cycle Effects on SealsThermal Cycle Effects on Seals
(Samples held at pressure for 24 hours at 800°C; tested for leaks using a 4 psig differential in the testing gas)
Sealing materials Test conditions Notes
430SS/G501 (45µm)/Ni-YSZ
wet forming gas Failed after 20 cycles; Ni-YSZ fracture
430SS/G501(45µm)/YSZ air Failed after 60 cycles; YSZ fracture
430SS/G812 (20µm)/Ni-YSZ
forming gas 10 cycles; Ni-YSZ fracture
430SS/G812 (20µm)/Ni-YSZ
forming gas Failed after 30 cycles; Ni-YSZ fracture
430SS/G812(25µm)/Ni-YSZ
forming gas 32 cycles without failure
1 Glass prepared by a commercial vendor (MO-Sci)2 Glass prepared at UMR
Hermetic Seals After Initial Multiple Thermal CyclesHermetic Seals After Initial Multiple Thermal Cycles
17Materials and Systems Research, Inc.
HermeticityHermeticity and Materials Compatibility and Materials Compatibility
Little Evidence for Significant Reactions @ Seal InterfacesLittle Evidence for Significant Reactions @ Seal Interfaces
SS430
G#50
4.0 4.5 5.0 5.5 6.00
50
100
150
200
250
300
ba
Cr peak
coun
ts p
er s
econ
d
energy (ev)
a
b
Ten days in wet forming gas at 800oC
18Materials and Systems Research, Inc.
Cathode Characteristics in SOFC/SOEC/SOFEC ModesCathode Characteristics in SOFC/SOEC/SOFEC Modes
-1
-0.5
0
0.5
1
1.5
2
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2
Current density (A/cm2)
Cel
l vol
tage
(V)
15 11 7.5 3.8 0 3.8 7.5 11 15
Fuel consumption (SCCM/cm2)Hydrogen production (SCCM/cm2)
Ele
ctri
city
savi
ng
• Cells: 2cm2 active area• Reversible CA, LSCrM• 800oC• Cell was tested in three
modes: SOFC; SOEC; SOFEC
I – SOFC modeII – SOEC mode
I/IV – SOFEC modeI/IV – H2 generation @ Ca
II – H2 generation @ An
-1
-0.5
0
0.5
1
1.5
2
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2
Current density (A/cm2)
Cel
l vol
tage
(V)
15 11 7.5 3.8 0 3.8 7.5 11 1515 11 7.5 3.8 0 3.8 7.5 11 15
Fuel consumption (SCCM/cm2)Hydrogen production (SCCM/cm2)
Ele
ctri
city
savi
ng
• Cells: 2cm2 active area• Reversible CA, LSCrM• 800oC• Cell was tested in three
modes: SOFC; SOEC; SOFEC
I – SOFC modeII – SOEC mode
I/IV – SOFEC modeI/IV – H2 generation @ Ca
II – H2 generation @ An
−− +=+ 222 OHe2OH
−− += e2O21O 2
2
Anode – Ni
CathodeElectrolyte
SOEC mode
H2 +H2O (H2O ~ 10% to 100%)
I
−e2 P.S.
Loa
d
+
-
+-
Air
−− +=+ 222 OHe2OH
−− += e2O21O 2
2
Anode – Ni
CathodeElectrolyte
SOEC mode
H2 +H2O (H2O ~ 10% to 100%)
I
−e2 P.S.
Loa
d
+
-
+-
I
−e2 −e2 P.S.
Loa
d
+
-
+-
Air
SOFC mode
Anode – Ni
CathodeElectrolyte
−− +=+ e2OHOH 22
2
−− =+ 22 Oe2O
21
Syngas & CH4
H2 +H2O (H2O ~ 0% to 90%)
I
−e2
Loa
d
+
-
Air
SOFC mode
Anode – Ni
CathodeElectrolyte
−− +=+ e2OHOH 22
2
−− =+ 22 Oe2O
21
Syngas & CH4
H2 +H2O (H2O ~ 0% to 90%)
I
−e2 −e2
Loa
d
+
-
Air
Anode – Ni
CathodeElectrolyte
SOFEC mode
−− +=+ 222 OHe2OH
Syngas & CH4
−− +=+ e2OHOH 22
2
H2 +H2O (H2O ~ 10% to 100%)
Loa
d
I
−e2 +- P.S.
+
-Anode – Ni
CathodeElectrolyte
SOFEC mode
−− +=+ 222 OHe2OH
Syngas & CH4
−− +=+ e2OHOH 22
2
H2 +H2O (H2O ~ 10% to 100%)
Loa
d
I
−e2 +- P.S.
+
-
Loa
d
I
−e2 −e2 +- P.S.
+
-
Transpose to SOEC direction
19Materials and Systems Research, Inc.
SOFEC Stability TestSOFEC Stability TestSingleSingle--cell Stack with 100 cmcell Stack with 100 cm22 PerPer--cell Active Areascell Active Areas
Per cell production rate: 13.92 standard liters of H2 per hour, or 27.54 grams per day
20Materials and Systems Research, Inc.
SOFCSOFC--SOFEC Hybrid Power & HSOFEC Hybrid Power & H22 CogenerationCogeneration
13-SOFC in power generation
20-SOFEC in H2 production
Power & H2 cogeneration
Co-Production rate: Net power output @ 130 Watts and 270 standard liters of H2 per hour (or 0.534 kg/day) CoCo--Production rate: Net power output @ 130 Watts and 270 standard lProduction rate: Net power output @ 130 Watts and 270 standard liters of Hiters of H22 per hour (or 0.534 kg/day) per hour (or 0.534 kg/day)
SOFC (13-cell) + SOFEC (20-cell) Hybrid Stack for a Continuous H2 ProductionTemperature @ 780oC, AN: Syngas; CA1: air; CA2: H2O; Uf/Uair/Usteam=50/60/40 --> 50/50/40
-10
-5
0
5
10
15
20
25
0 10 20 30 40 50 60 70 80
Time (hr)
Volta
ge (V
)
0
5
10
15
20
25
30
35
Hyb
rid s
tack
cur
rent
(A)
SOFEC voltage SOFC voltage Stack current
Stack currentOvernight H2 ProductionH2 Production
lower Uair to 50%
21Materials and Systems Research, Inc.
Next Generation Stack Design for the 5 kW SystemNext Generation Stack Design for the 5 kW System
• Larger stacks (60+ cells per stack)• Thermal and flow management
Novel flow geometry for in-stack temperature and flow optimization
• Improved sealing• Design for assembly
Stack components have been minimized to reduce stacking time and errorImproved reliability
• Reduced pressure drop over previous designs
22Materials and Systems Research, Inc.
Balance of Plant HardwareBalance of Plant Hardware
• Combustors, reformers and steam generators are being fabricated and tested prior to system integration.
• Catalytic combustors ensure minimal noxious byproducts.
Catalytic combustor
23Materials and Systems Research, Inc.
Control SystemControl System
• Design of electronic control algorithm for the SOFC-SOFEC hybrid system.
• Autonomous operation enables to perform all stacks at maximum fuel efficiency and producing hydrogen from excess capacity.
• Multiple stacks in parallel operation to increase reliability and disrupt failure cascades.
• Acquisition of electronic control hardware and integration with system software.
• Pre-test of power electronics and load leveling systems before beingintegrated into the overall system.
24Materials and Systems Research, Inc.
Future Work (FY 08 Future Work (FY 08 –– FY 09)FY 09)FY 08FY 08
• Materials DevelopmentExploring an advanced cathode materialContinuous investigation of anode substrates: equi-biaxial test and flexural strength under both air and H2 at working temperatures; effect of thermal cycles on strength
• 5 kW Hybrid System FabricationBOP components fabricationStack assembly, integration and burn-inImplementation and optimization of system controls
FY 09FY 09• 5 kW Hybrid System Assembly and Evaluation
5 kW hybrid system assemblySystem testing and evaluationHydrogen production cost analysis using H2A model
25Materials and Systems Research, Inc.
Project SummaryProject SummaryRelevance: Investigate an alternative approach to provide low-cost and highly efficient
distributed electricity and hydrogen
Approach: Develop a 5 kW SOFC-SOFEC hybrid system based on innovative materials development and system design research to co-generate hydrogen and electricity
Materials development: - Evaluated redox stability and long-term stability of the promising cathode material for SOFEC applications. - Finalized two promising “invert” glass compositions from 81 candidates. Seals survived after 30+ thermal cycles in reducing/oxidizing atmospheres. - Investigated effects of reduction on microstructure development and phase formation, elastic properties as a function of temperature, and effects of porosity, composition & microstructure on strength. 5 kW hybrid system development: - Evaluated long-term stability tests of hydrogen production to reduce cost. –Finalized the design of hybrid modules with improved thermal management and flow optimization. – Designed and fabricated major BOP components. –Designed hybrid system control algorithm and acquired control hardware.
Proposed Future Continue implementing mechanical/thermal analyses of anode supports; fabricate and evaluate BOP components and optimize hybrid system controls; implement 5 kW system experimental evaluation and perform cost analyses using DOE H2A model.
Technologies Accomplishments and Progresses:
Research:
top related