Chemical and transport behaviors in a microfluidic reformer with catalytic-support membrane for efficient hydrogen production and purification

Abstract

Microchannel reformer integrated with H₂ selective membrane offers an efficient, compact and portable way to produce hydrogen. The performance of a membrane-based microfluidic reformer is restricted by species diffusion limitation within the porous support of the membrane. Recent development in novel catalytic-supported membranes has the potential to enhance H₂ production by decimating the diffusion limitation. Loading a Pd-Ag layer on to a Ni-catalytic porous support, the membrane achieves both H₂ separation and production functions. In this study, a two-dimensional CFD model combined with chemical kinetics has been developed to simulate a microchannel autothermal reformer fed by methane. The species conversion and transport behaviors have been studied. The results show that the permeation process enhances the mass transport within the catalytic layer, and as a result, the reactions are intensified. Most notably, the effectiveness factor of the water-gas shift reaction as high as 6 is obtained. In addition, the effects of gaseous hourly space velocity (GHSV) on methane conversion and H₂ flux through the membrane are also discussed, and an optimal value of GHSV is suggested.