DE-FC26-05NT42626
Techno-EconomicAnalysisof
SOFC-TEHybridPower GenerationSystems
JifengZhang, JohnYamanis, Benoit Olsommer, UnitedTechnologies ResearchCenter, EastHartford, CT06108 DougCrane, LonBell, BobCollins, BSST,LLC, Irwindale,CA
Introductionand Background
Goal: • • • • Combine TE and SOFC Net power Efficiency: 65% Factory Cost: $400/kW Life: 10 years/40,000 hours
SOFC-TE Modeling Tools and Process
Another concept
System Performance:
Optimization
0.70
SOFC + GT + TE(ZT=2.5)
Screening Process
0.68
TE efficiency contribution
0.65
Downselect Downselect System specs, IP, Gaps,
0.66
SOFC + GT + TE(ZT=0.85)
SOFC-GT efficiency contribution
System efficiency
0.60
0.64
Efficiency
SOFC + GT
0.62 0.60 0.58 0.56
Concepts
Techno-Economic Analysis
0.55
0.50
Systems Tool (gPROMS)
SOFC only
0.45 0.54 541
Multiple System Analysis (Design, Off-design, Economic) Design Optimization (Design maps)
Library (gPROMS)
Scope: Application: 200 kW Plant in the year 2011 Number of units/year: 2.5GW market (Unit size: 5-200 kW) Fuel: Coal gas Baseline system
537
533
529
525
522
518
514
511
507
0.40 0 2 4 6 8 10 SOFC turbine pressue ratio
SOFC-TE interface temperature (C)
Performance Library
Cost Library
700
Cost Models: • • • • • • Simple, ambient pressure, standalone 10kW SOFC Efficiency: 45% $400/kW (SECA, Phase III goal, 2011) No reformer, no sulfur trap With cathode recirculation Anode recycle
Air Heat Recovery Fuel
Exhaust
System unit cost ($/kWe)
600
TE TE air blower Misc (Piping etc) Insulation PCS
500
• • • •
SOFC-CHP cost modeling equations used as baseline Calibrated to match the published cost data from DOE (ADL report) Considered volume effect to non-generic components such as turbine PCS cost regression based on solar PV PCS cost and size data
No 1 2 3 4 5 6 7 8 9 10 11 12 13 Component Stack (SOFC) Turbine Air compressor Cathode Blower Anode Blower Pressure vessel Air preheater PCS BOP Insulation Burner TE blower TE Equation Scale Var Unit $=0.35P(28.18(N_cell/P)+120.4)*((290.94-30.198*LOG(P))/130)*(Vol/Vol0)^(-0.1278) DC pow kW $=272*(P/1.3)^0.95*(Vol/Vol0)^(-0.1278) Shaft pow kW $=60*(vdot/27.75)^0.703 vdot CFM $=100*(vdot/27.75)^0.703 vdot CFM $=100*(vdot/27.75)^0.703 vdot CFM $=5P(P/200)^(-.25)*(Vol/Vol0)^(-0.1278)*((PR-1)^0.5 P, PR kW/1 $=158*(Mdot/0.028) Mdot kg/s $=(290.94-30.198*LOG(P)) *P AC pow kW $=85*P/5.6 DC pow kW $=54*P/5.6 DC pow kW $=42*(Mdot/0.028)^0.55; Mdot kg/s $=60*(vdot/27.75)^0.703 $=($TE_mat+$TE_hot+$TE_cold+$TE_ass)*(1+overhead_ratio)weight kg Life 5 5 3 2.5 2.5 3 5 5 10 10 5 20 Production Volume Note 2.5GW total capacity 50000 for 5kW SOFC 1 2,3 3 3 50000 for 5kW SOFC 3 4 50000 for 5kW SOFC 50000 for 5kW SOFC 50000 for 5kW SOFC 3 5
400
Pressure_Vessel Turbine assembly Air Compressor
300
PreheatGas BlowCathode BloweAnode
200
PreheatAir Burner Stack
100
0 5 10 15 20 25 30 35 40 45 50 75 100 125 150 175 200 Stack size (kWe )
FutureDevelopment
Ambient Pres SOFC-TE Application Major advantages System efficiency Commercial / small SOFC Heat recovery and flexibility 51% 6% point 2 Yes Pressurized SOFC-TE Large utility power generation High efficiency 65% 1% point 1 No
Stack
TE 1 TE 2
SOFC Air
*: For the notes, please see the Cost Modeling Additional Notes in the Backup Slides
Specific Objectives: • To understand the factors affecting the system performance and cost • To find the best system integration concept for SOFC-TE • To create development strategy for the identified system concept
Results
Best Concept: SOFC + 1TE + 2 Compressors
Source Air2 MixAir Cathode Blower
2
TE
Sink Air
TE efficiency addition No. of TE generators
PreheatAir
Air Blower
CHP Potential
Approach
• Generate system integration concepts Different configurations to combine SOFC and TE Trade-off between component performance and cost • Benchmark thermoelectric materials for system integration Identify TE materials potentially used for the hybrid system • Develop modeling tools to analyze system performance and cost Lumped modeling of major component physics Cost modeling as a function of component size and sales volume • Down-select the best system concept Use system efficiency and cost as the down-selection criteria • Identify the barriers and enablers for developing the best concept
Cathode
Split Cathode
1
Mix Burn
Burner
TE
Sink Air
1
Anode
Split Anode
Preheat Gas
Gas Comp
2
Expander
Anode Blower
Split Fuel
1
Compressor
~
Exhaust gas
Conclusions
• To meet the 65% efficiency and $400/kWe cost target, a pressurized SOFC-TE is identified as the best system • The best system pressure ratio is approximately 4.0 • TE contributes approximately 1-2% of system efficiency in the optimal SOFC-TE configurations • Optimal SOFC-TE system provides little CHP potential due to limited waste heat • TE has better value as a bottoming cycle generation device for small size (200kW and below) and ambient pressure SOFC. • Ambient system is also better for CHP
Source Fuel
Source Air
Mix Fuel
ZT: 0.8 - 2.5
SOFC
Air preheater: another TE potentially • Cold inlet: after air compressor • Hot inlet: after expansion Limited power generation