Developing a dynamic model of a methanol steam reformer for use in a fuel cell propulsion system

摘要

Transportation fuel cell systems are being developed for methanol as the on-board fuel instead of the difficult-to-store hydrogen. Two such systems under development include polymer electrolyte and phosphoric acid fuel cells (PEFC, PAFC), which operate at 80(degrees)C and 200(degrees)C, respectively. Because of these relatively low operating temperatures, the methanol must be converted to a hydrogen-rich gas before it can be fed to the fuel cell stack (except in the case of the direct electrochemical oxidation of methanol, presently under development). Steam reforming of methanol is used in the PAFC buses developed by H-Power Corp. A methanol steam reformer is also being developed by General Motors (GM) for light-duty vehicle PEFC systems. Earlier, we described results from steady-state and off-design simulations of methanol-fueled PEFC systems. These results indicated that the dynamic response of the fuel cell system is likely governed by the transient performance of the methanol reformer (rather than the dynamic performance of the fuel cell stack or other balance-of-plant components). This paper discusses the development of a dynamic model for the methanol steam reformer, which will subsequently be used in simulating the dynamic performance of the complete fuel cell system.