Experimental study on the performance of hydrogen production from miniature methanol-steam reformer integrated with Swiss-roll type combustor for PEMFC

摘要

A miniature plate-type hydrogen production reactor using methanol as fuel was designed and tested. This reactor is composed of a catalytic combustor, vaporizer, reformer, and methanator. All components were fabricated on one piece of rectangular quartz glass plate 50 mm×44 mm ×7 mm in size. The combustor was fabricated on one side of the glass plate with a Swiss-roll type channel in which the Pt/Al_2O_3 particles were loaded in segmented form to catalyze the combustion. A spiral channel was fabricated on the other side of the plate and divided into three sections: a vaporizer for liquid methanol-water mixture vaporization, a reformer for methanol-steam reforming catalyzed by CuO/ZnO/Al_2O_3 particles and a methanator for carbon monoxide (CO) removal catalyzed by Ru/Al_2O_3 particles. The test results indicated that this reactor successfully produced H_2 and had thermal efficiency ranging from 13% to 35%. The reactor performance depends on the feed rates to the combustor and reformer, respectively. High methanol conversion can be obtained from either a low feed rate to the reformer or a high feed rate to the combustor. However, both cases also produce high CO concentrations. The CO methanation reaction was used to reduce the CO concentration. It was found that the methanation reaction depends greatly on the reactor temperature with high temperature not being favorable to this reaction. High CO conversion and low H_2 consumption with low methanol conversion result when the reaction temperature is low. Thermal management for producing suitable temperature and catalyst activity improvement in high reaction temperature for the methanator are both needed in the integrated reactor design to reduce the CO concentration down to acceptable levels for fuel cell operation.