A catalytic membrane reactor for water-gas shift reaction

We conducted the WGS reaction on a catalytic membrane reactor consisting of a WGS catalyst bed, Pt/CeO 2 and thin, defect-free, Pd-Cu alloy membranes. The presence of CO and other gases with H 2 reduced the H 2 permeation through the membrane by more than 50% and the effect of the other gases on the permeation reduction decreased in the following order: CO>CO 2 >N 2 . In a catalytic membrane reactor with helium sweep gas, the CO conversion was improved by about 65% compared with the catalyst without any membrane, and the CH 4 formed from an undesirable side reaction was significantly reduced. Although the H 2 permeation was severely reduced by surface phenomena such as blocking of available H 2 dissociation sites by CO, CO 2 and steam, the CO conversion was notably improved by the membrane presence. Moreover, the CO conversion was maintained at 98% even after 60 h of reaction and our Pd-Cu-Ni alloy membrane withstood the exposure of CO and the other gases. However, for separation of pure H 2 , a newly designed, catalyst-membrane system is required with better sealing and the ability to withstand the high operating pressure that drives the H 2 permeation.