Hydrogen production capacity of membrane reformer for methane steam reforming near practical working conditions

Currently, H2 production techniques for application to proton exchange membrane fuel cells (PEMFC) are intensively investigated, aiming to realize a clean hydrogen society. Due to the limitation by the thermodynamics of methane steam reforming (MSR), multi-reactions and multi-steps should be performed before the generated H2-rich gas could be delivered to PEMFC, which inevitably increases the cost of H2. However, using a thermodynamic shifting membrane reformer, H2 could be produced compactly from MSR, provided that the catalyst showed high performance for MSR reaction and membrane efficiently removed H2 from the reaction zone. We presented here a Pd-based membrane reformer for MSR reaction. In contrast with previous reports, nickel-based catalyst pre-reduced at high temperature was applied in this work, as well as high performance Pd-based membrane. The performances of the membrane reformer in terms of H2 production capacity were also widely investigated. It was found that combination of an active catalyst for MSR and a H2 ultra-permeable Pd membrane obtained high flux of H2 across the membrane and recovery rate of H2 in the membrane reformer. For instance, 98.8% methane conversion, over 97.0% selectivity to CO2 and over 95.0% recovery rate of H2 were obtained under mild working conditions. Simultaneously, the hydrogen flux across the membrane reached 18.6 m3/(m2 h), and Pd-based pure H2 production capacity significantly increased and reached around 387.5 m3/(kgPd h) in membrane reformer. Further work on stability investigation may develop an efficient on-site route of H2 production process for application to on-site power generation using PEMFC.