A CFD study on H2-permeable membrane reactor for methane CO2 reforming: Effect of catalyst bed volume

Abstract A 2D axisymmetric model is developed for a H2-permeable membrane reactor for methane CO2 reforming. The effect of catalyst bed volume on CH4 conversion and H2 permeation rate is investigated. The simulation results indicate that catalyst bed volume with a shell radius of 9 mm is optimal for a tubular Vycor glass membrane with a diameter of 10 mm and H2 permeance of 2x10−6 mol/m2/Pa/s. The concentration polarization at the retentate side and the accumulation of H2 at permeate side make it hard to extract the H2 production at the zone far from the membrane surface. Though increasing pressure at the retentate side enhances H2 permeation, CH4 conversion is even decreased due to unfavorable thermodynamics. And increasing sweep gas flow rate at permeate side benefits to both CH4 conversion and H2 permeation. This work highlights the importance of determining the optimal catalyst bed volume to match the membrane in the design of membrane reactors.