Simulation Study on the Applicability and Performance of Conventional and Reverse-Selective Membranes for Upgrading of H2/CO2 Mixtures via Gas-Permeation

Abstract

Upgrading of a H₂/CO₂-mixture via gas-permeation process applying conventional glassy and reverse-selective rubbery membranes is systematically evaluated in Aspen Plus. The model of the gas-permeation unit is based on the solution-diffusion mechanism and considers the discretization of the membrane’s surface. Calculations are based on representative pure component permeabilities from literature for both membrane types, assuming a feed concentration of 41 vol% CO₂ and a product gas specification of 90 vol% and 97 vol% H₂ at a H₂-recovery of 90 %, respectively.
Results for single stage separation show, that only with glassy membranes product gas specifications could be reached in case of the lower quality requirements. Applying a two stage gas-permeation process enables meeting the higher quality requirements with both membrane types. Different module and compressor configurations have been screened including configurations with and without recirculation. Interesting results are obtained combining both membrane types, resulting in a low total membrane area.