Effect of Pressure on High-Temperature Water Gas Shift Reaction in Microporous Zeolite Membrane Reactor

Abstract

A water gas shift (WGS) membrane reactor (MR) has been constructed using a MFI-type zeolite disk membrane packed with a cerium-doped ferrite catalyst. The WGS reaction was performed at high temperatures of 400–550 °C, and the effect of reaction pressure on the MR performance was investigated in a range from 2 to 6 atm with the permeate side swept by nitrogen at atmospheric pressure. Increasing temperature and pressure enhance both the reaction rate and the rate of H2 membrane permeation that in turn significantly enhances the CO conversion. The equilibrium limit of CO conversion can be surpassed in the MR at high pressure and/or high temperature. It has been demonstrated in this study that membranes with moderate H2 selectivity can be effective for enhancing CO conversion at high operation temperature and pressure with the cost of low H2 concentration in the permeate stream. The timely removal of H2 from the catalyst bed dramatically reduced the undesirable methane production because H2 is a reactant for ...