Development of a coupled reactor with a catalytic combustor and steam reformer for a 5kW solid oxide fuel cell system

The methane (CH4) conversion rate of a steam reformer can be increased by thermal integration with a catalytic combustor, called a coupled reactor. In the present study, a 5kW coupled reactor has been developed based on a 1kW coupled reactor in previous work. The geometric parameters of the space velocity, diameter and length of the coupled reactor selected from the 1kW coupled reactor are tuned and applied to the design of the 5kW coupled reactor. To confirm the scale-up strategy, the performance of 5kW coupled reactor is experimentally investigated with variations of operating parameters such as the fuel utilization in the solid oxide fuel cell (SOFC) stack, the inlet temperature of the catalytic combustor, the excess air ratio of the catalytic combustor, and the steam to carbon ratio (SCR) in the steam reformer. The temperature distributions of coupled reactors are measured along the gas flow direction. The gas composition at the steam reformer outlet is measured to find the CH4 conversion rate of the coupled reactor. The maximum value of the CH4 conversion rate is approximately 93.4%, which means the proposed scale-up strategy can be utilized to develop a large-scale coupled reactor.