A porous α-alumina tube supported MFI-type zeolite membrane was modified by depositing molecular silica species into the zeolitic channels via in situ catalytic cracking of methyl diethoxysilane at a limited number of active sites. The modified zeolite membrane exhibited a H2/CO2 perm-selectivity of 68.3 with a H2 permeance of 2.94 x 10-7mol/m2sPa at 550C. The modified zeolite membrane tube was packed with a cerium-doped ferrite catalyst for water gas shift reaction at 400 to 550C. The water gas shift reaction results demonstrated that the zeolite membrane reactor was effective in enhancing CO-conversion at kinetically favorable high temperatures especially when high space velocity and low steam-to-CO ratios, RH2O/CO, were used. At 550C with a high space velocity of 60000/h and a RH2O/CO of 1.0, the membrane reactor achieved a conversion of 81.7%; significantly higher than the 62.5% obtained in the traditional packed-bed reactor, which was well above the equilibrium conversion (65%) as well. The results also suggested that, at temperatures >500C), further enhancement of CO-conversion to near completion required both membrane improvement and high-pressure operation.

Modified Zeolite Membrane Reactor for High Temperature Water Gas Shift Reaction. Z.Tang, S.J.Kim, G.K.Reddy, J.Dong, P.Smirniotis: Journal of Membrane Science, 2010, 354[1-2], 114-22