Pure H2 production through hollow fiber hydrogen-selective MFI zeolite membranes using steam as sweep gas

Hollow fiber MFI zeolite membranes were modified by catalytic cracking deposition of methyldiethoxysilane to enhance their H-2/CO2 separation performance and further used in high temperature water gas shift membrane reactor. Steam was used as the sweep gas in the MR for the production of pure H-2. Extensive investigations were conducted on MR performance by variations of temperature, feed pressure, sweep steam flow rate, and steam-to-CO ratio. CO conversion was obviously enhanced in the MR as compared with conventional packed-bed reactor (PBR) due to the coupled effects of H-2 removal as well as counter-diffusion of sweep steam. Significant increment in CO conversion for MR vs. PBR was obtained at relatively low temperature and steam-to-CO ratio. A high H-2 permeate purity of 98.2% could be achieved in the MR swept by steam. Moreover, the MR exhibited an excellent long-term operating stability for 100 h in despite of the membrane quality. (c) 2015 American Institute of Chemical Engineers AIChE J, 61: 3459-3469, 2015