Optimal design and fabrication of surface microchannels on copper foam catalyst support in a methanol steam reforming microreactor

Abstract

Methanol steam reforming microreactor has been considered as one of the effective way to provide the online hydrogen source for proton exchange membrane fuel cell. In order to further improve the reaction performance of microreactor, the surface microchannels with different sizes and qualities are proposed to optimize the geometrical structure of copper foam as catalyst support. Later, the methanol concentration distribution in copper foams was investigated by numerical analysis using finite element method. Based on the simulation results, different surface microchannels on copper foams are designed and fabricated by laser processing method. The configuration of surface microchannel (quantities, widths and distributions) on copper foams was investigated under different gas hourly space velocities and reaction temperatures and the optimal one was obtained. Our results show that copper foams with surface microchannels can provide a larger diffusion space and enhance the uniform distribution of methanol, leading to improvement in reaction performance. Moreover, it is found that the uniformity of methanol concentration distribution in copper foam can be further improved when reactants pass through microchannel from inlet with larger width to outlet with smaller width. The best reaction performance of microreactor for hydrogen production is obtained for the copper foam with gradient width microchannels because of its larger specific surface area and better loading performance of catalysts.