Experimental and Simulation Studies of Effects of Operating Conditions and Membrane Properties On the Performance of Zeolite Membrane Reactors for High Temperature Water Gas Shift Reaction

Experimental and Simulation Studies of Effects of Operating Conditions and Membrane Properties on the Performance of Zeolite Membrane Reactors for High Temperature Water Gas Shift Reaction

Seok-Jhin Kim, Shaowei Yang, Junhang Dong

Department of Chemical & Materials Engineering, University of Cincinnati, Cincinnati, OH 45220, USA

ABSTRACT

Modified microporous MFI-type zeolite membranes have been studied as high temperature water gas shift (WGS) membrane reactors (MR) using a cerium-doped ferrite (Fe/Ce) catalyst. The effects of the reaction conditions and the membrane separation properties on the CO-conversion (c_CO) in the MR were investigated experimentally and by simulations using a simple one-dimensional model which was validated by the experimental data. The experimental results have demonstrated that the zeolite MRs with moderate H₂ separation performance are capable of overcoming the equilibrium CO-conversion (c_CO,e) existing in traditional packed-bed reactors at operating temperatures of >500^oC where CO reaction rate is rapid enough to effectively minimize the permeation of the unreacted CO. The model calculations have shown that near-completion CO-conversion (c_CO>99.5%) may be achieved under realistic operating temperature, pressure, space velocity and catalyst load even for membranes with moderate H₂ selectivity, e.g. (a_H2/CO2<50) and H₂permeance (<3×10^-7mol/s·m²·Pa).