Dimensionless analysis of reverse water gas shift Packed-Bed membrane reactors

Abstract

A dimensionless analysis was performed on the reverse water gas shift packed-bed membrane reactors (RWGS PBMRs) to shift the equilibrium of the RWGS reaction by in-situ H2O removal at low temperatures. Using Damköhler, Péclet, and Stanton dimensionless numbers, the effects of sweep to reactor flow and pressure ratios, flow configuration, temperature, and H2O/H2 perm-selectivity were studied for CuO/ZnO/Al2O3 and Ru-Cu/ZnO/Al2O3 catalysts. The counter-current configuration resulted in higher CO2 conversions at milder sweep pressures when compared to the co-current configuration. It was determined that the application of RWGS PBMRs had to be limited to temperatures below 300 °C to shift the reaction equilibrium. It was concluded that to meaningfully intensify the RWGS reaction by PBMRs, weight hourly space velocities should be lowered to values below 1 hr-1 using membranes with H2O/H2 perm-selectivities greater than 100 and H2O permeance in the range of 10-6-10-5 mol m-2 s-1 Pa-1.