Computational fluid dynamics modeling of the millisecond methane steam reforming in microchannel reactors for hydrogen production
Methane steam reforming coupled with methane catalytic combustion in microchannel reactors for the production of hydrogen was investigated by means of computational fluid dynamics. Special emphasis is placed on developing general guidelines for the design of integrated micro-chemical systems for the rapid production of hydrogen. Important design issues, specifically heat and mass transfer, catalyst, dimension, and flow arrangement, were explored. The relative importance of different transport phenomena was quantitatively evaluated, and some strategies for intensifying the reforming process were proposed. The results highlighted the importance of process intensification in achieving the rapid production of hydrogen. High heat and mass transfer rates derived from miniaturization of the chemical system are insufficient for process intensification. Improvement of the reforming catalyst is also essential. The efficiency of heat exchange can be improved greatly if the reactor dimension is properly designed. Thermal management is required to improve the reliability of the integrated system. Co-current heat exchange improves the thermal uniformity in the system. The catalyst loading is a key factor determining reactor performance, and must be carefully designed. Finally, engineering maps were constructed to achieve the desired power output, and favorable operating conditions for the rapid production of hydrogen were identified.