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Auxiliary power for mobile applications
- L. Gaines et al., Argonne National Laboratory (2010)
Durability of SOFC-Based Auxiliary Power Units Thomas A. Trabold, - - PowerPoint PPT Presentation
Durability of SOFC-Based Auxiliary Power Units Thomas A. Trabold, - - PowerPoint PPT Presentation
Durability of SOFC-Based Auxiliary Power Units Thomas A. Trabold, Mark R. Walluk, Jiefeng F. Lin and Daniel F. Smith Golisano Institute for Sustainability (GIS) Center for Sustainable Mobility Rochester Institute of Technology October 12, 2011
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Solid oxide fuel cells (SOFCs) vs. Polymer electrolyte membrane fuel cells (PEMFCs)
Characteristic SOFC PEMFC
Temperature 800°C 80°C Fuel Reformed hydrocarbon (H2 + CO) Pure H2 Materials Expensive (e.g., Inconel) Cheaper (lower-grade SS) Catalysts Mixed PGM and non-PGM Pt-alloy Start-Up Slow (hours) Fast (minutes or seconds) Applications
- Stationary power (CHP)
- Auxiliary power units for heavy-
duty trucks
- Emergency back-up power
- Automotive propulsion
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Equilibrium analysis: Modeling based on minimization of Gibbs free energy predicts “ideal” fuel conversion if all reactions proceed to thermodynamic equilibrium.
Dominant degradation mode: Solid carbon (soot) formation during diesel reforming Predictions indicate that carbon formation would be severe during start-up transient when temperature is below normal operating condition (NOC)
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A single-tube reformer enables empirical studies of the sensitivity of the reforming process to key system control parameters: air flow, fuel flow, recycle rate, temperature, etc.
- W. Schindler et al., SAE Paper 2004-01-0968 (2004)
Lin, J., Trabold, T.A. and Walluk, M.R., “Reformer air control to mitigate carbon formation during diesel reforming for solid oxide fuel cells,” in preparation for submission to Journal of Power Sources (2011).
Direct Measurement of Carbon Concentration
Single-tube reformer experiments used to measure carbon during thermal transients
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Trabold, T.A., Lylak, J., Walluk, M.R., Lin, J. and Troiani, D., “Measurement and analysis of carbon formation during diesel reforming for solid oxide fuel cells,” submitted for publication to International Journal of Hydrogen Energy (2011).
Previous research described ethylene formation as a result of thermal decomposition
- f diesel, followed by carbon formation via heterogeneous reaction within the
- reformer. Our novel results showed a strong correlation, with a transition around a
critical value of [C2H4] = 0.8%. Correlation between ethylene and carbon concentrations
SLIDE 7
Test hypotheses developed from simplified analysis and experiments on full fuel reformer sub-system and production-intent APU system
Smith, D.F., Trabold, T.A., Walluk, M.R., Wodenscheck, J., Haselkorn,
- M. and Nasr, N., “Accelerating the Transition of Fuel Cell Systems,”
Final Report, TARDEC Contract W56HZV-08-C-0671 (2011).
Fundamental understanding applied to full APU system
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Apply economic analysis and life-cycle assessment (LCA) to select among technology pathways to minimize GHG emissions and maximize value
Table 1 – Locally available bio-fuels assessed in the present study
Fuel
- Approx. lower heating value
(kJ/g) Need to consider sulfur content Need to consider water content Ultra-low sulfur diesel , ULSD (baseline) 42.3
× × × ×
Bio-diesel from grease 38.9
× × × × × × × ×
Ethanol from corn silage 27.0
× × × ×
Bio-butanol 34.4
× × × ×
Compressed bio-gas (assumed 70% methane) 23.0
× × × × × × × ×
Lin, J., Smith, D.F., Babbitt, C.W. and Trabold, T.A., “Assessment of bio-fuel options for solid oxide fuel cell- based auxiliary power units,” Proceedings of the IEEE International Symposium on Sustainable Systems and Technology (ISSST), Chicago, May 2011.
Apply same methodology to waste-derived bio-fuel and bio/petro blend systems
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