CFD study of heat and mass transfer in ethanol steam reforming in a catalytic membrane reactor

This work shows the analysis of ethanol steam reforming process within a catalytic membrane reactor. A 2-D non-isothermal CFD model was developed using Comsol Multi-physics, based on previous experimentally validated isothermal model. A comprehensive heat and mass transfer study was carried out utilizing the model. Operating conditions such as liquid hourly space velocity (LHSV) (3.77-37.7 h(-1)), temperature (673-823 K), reaction side pressure (4-10 bar) and permeate side sweep gas flow pattern were discussed. A temperature gradient along the reactor was observed from the model and a "cold spot" was seen at the reactor entrance area, which is unfavorable for the highly endothermic ethanol steam reforming process. By changing the sweep gas pattern to counter-current, the "cold spot" appears to be smaller with a reduced temperature drop. By studying the individual reaction rates, reverse methane steam reforming (methanation) was observed, caused by the low temperature in the "cold spot". Optimal operating conditions were found to be under LHSV = 37.7 h(-1) and counter-current sweep gas conditions. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.