Enhancing stability in parallel plate microreactor stacks for syngas production

Recent work found that methane fueled small microreactor stacks for syngas production are unstable due to external heat losses primarily that cause the outmost combustion channels to fail. Methods for improving stability are investigated in this work using computational fluid dynamics (CFD) simulations of parallel plate microreactors consisting of alternating combustion and steam reforming channels with platinum and rhodium catalytic surfaces, respectively. To study the effect of combusting a more reactive fuel, a single step rate expression for hydrogen combustion on platinum is derived from a previously published microkinetic model. The most effective means for improving stability is combusting hydrogen or increasing the platinum catalyst loading in the outmost combustion channels. These results should be applicable to other systems that may not be stable at small scales. Finally, several stability enhancement methods are contrasted in terms of throughput and efficiency.