Transport Characteristic Study On Microscale Methanol Steam Reforming For Hydrogen Production

Micro-scale methanol steam reforming is one of the major solutions to solve the fuel supply for the proton exchange membrane fuel cell. Different from traditional macro-scale steam reforming reaction, since micro-scale methanol steam reforming for hydrogen production involves many complex processes, there still remain much work to conduct regarding its reaction mechanism, micro heat and mass transfer phenomena, catalyst component selection and micro-reactor structure optimization.In this paper, through the combination of numerical simulations and experiments, the impacts of the selection of the operation parameters, the optimization of the copper catalyst components, and the improvement of micro-reactor structure on methanol steam reforming were analyzed systematically. The relationship between the operation parameters and the conversion rate of methanol, the formation mechanism of carbon monoxide, as well as the connection between various structures, temperature distribution field, and flow filed were disclosed, providing useful reference for the transports characteristic study on micro-scale methanol steam reforming for hydrogen production. In order to study micro-scale methanol hydrogen technology, through EDM technology, an integrated micro-reactor was developed, which achieves several features, such as a fuel preheating, evaporation, reforming reaction, and re-substitution reaction section. Based on copper catalyst which was coated on the micro-channel, the effects of micro-reactor temperature, water-methanol ratio, the inlet temperature, and the inlet flow rate on the methanol conversion rate and product gases were studied. Wall-coated copper catalyst was self-made. The alternation of the copper-to-zinc ratio helped to analyze the effect of composition changes on the catalytic activity and the methanol conversion rate. At the same time, through numerical simulations, the various effects of comby fractal micro-channel network, extended parallel rectangular micro-channel, non-parallel rectangular micro-channel and traditional rectangular micro-channel on methanol conversion rate were disclosed. The results were compared, and verified by corresponding experiments.Based on this research, the reaction mechanism of methanol steam reforming was re-recognized, establishing a theoretical basement and practical solution for the appropriate selection of operation parameters, the optimization of catalyst, and the improvement of micro-structure. Finally, this study provided an insight into the phenomenon of micro-coupled-driven heat and mass transfer.