Fundamental characteristics of an integrated reactor with catalytic combustor and air pre-heater for compact solid oxide fuel cell systems

Abstract

Bulky volume limits the application of solid oxide fuel cell (SOFC) systems in some scenarios. In this paper, a compact integrated reactor with combustor and air pre-heater is proposed. It is adapted by coating combustion catalyst to the hot-side of a plate-fin heat exchanger. The fundamental steady/transient characteristics of the reactor are investigated at different inlet settings in the warmup condition of a metal-supported SOFC.Results show that the reactor has a balanced combustion performance with a minimum methane conversion rate of 85.1%, while it can be effectively improved by reducing the excess air ratio. The reactor has better heat exchange capability than the traditional series arrangement of independent combustor and air pre-heater. There is about 68.7% of the reaction heat extracted by direct metal-substrate conduction and this dominates the heat exchange process. The reactor also has a good transient response. Methane conversion can be stable within 12.5 min; meanwhile, the output air temperature shows a good capability to track the development of stack temperature. Both the air temperature rise rate around 35 ˚C min−1 and the rise trend of first fast and then slow can meet the requirements of stack quick warmup. Overall, the methane conversion development within the reactor and the temperature rise of the stack reinforce mutually, and both can stabilize more quickly in this case.