Demonstration of Energy Efficient Steam Reforming in Microchannels for Automotive Fuel Processing
A compact, energy efficient microchannel steam reforming system has been demonstrated. The unit generates sufficient reformate to provide H2 to a 10 kWe PEM fuel cell (when coupled with a water-gas shift and CO cleanup reactors). The overall volume of the reactor is 4.9 liters while that of the supporting network of heat exchangers is 1.7 liters . Use of a microchannel configuration in the steam reforming reactor produces rapid heat and mass transport which enables fast kinetics for the highly endothermic reaction. Heat is provided to the reactor by a combustion gas flowing in interleaved microchannels in cross flow with the reaction channels. A network of microchannel heat exchangers allows recovery of heat in the reformate product and combustion exhaust streams for use in vaporizing water and fuel, preheating reactants to reactor temperature and preheating combustion air. The microchannel architecture enables very compact and highly effective heat exchangers to be constructed. As a result of the heat exchange network, the system exhaust temperatures are typically ~50?C for the combustion gas and ~130?C for the reformate product while the reactor is operated at 750?C. While reforming isooctane at a rate sufficient to supply a 13.7 kWe fuel cell the system achieved 98.6% conversion with an estimated overall system efficiency after integration with WGS and PEM fuel cell of 44% (electrical output / LHV fuel). The efficiency estimate assumes integration with a WGS reactor (90% conversion CO to CO2 with 100% selectivity) and a PEM fuel cell (64% power conversion effectiveness with 85% H2 utilization for an overall 54% efficiency) and does not include parasitic losses for compression of combustion air. Acknowledgement The work described here was funded by the U.S. Department of Energy, Office of Transportation Technology as part of the OTT Fuel Cells Program.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 15003494
- Report Number(s):
- PNNL-SA-34534; HI0400000; TRN: US200434%%44
- Resource Relation:
- Conference: Microreaction technology : IMRET 5 : proceedings of the Fifth International Conference on Microreaction Technology , 303-312
- Country of Publication:
- United States
- Language:
- English
Similar Records
Progress on the Development of a Microchannel Steam Reformer for Automotive Applications
Development of a Rapid-Start On-Board Automotive Steam Reformer