Hydrogen permeation through a Pd-based membrane and RWGS conversion in H2/CO2, H2/N2/CO2 and H2/H2O/CO2 mixtures

•Effect of undesirable side reaction RWGS on hydrogen permeation was studied.•The operating pressure has an important effect on HR and CO2 conversion.•The feed flow rate has an important effect on HR.•CO2 content does not have a strong inhibition effect on H2 permeation.•H2O reduce the extension of the RWGS and reduce the HR.

This study investigated the effect of gases such as CO2, N2, H2O on hydrogen permeation through a Pd-based membrane −0.012 m2 – in a bench-scale reactor. Different mixtures were chosen of H2/CO2, H2/N2/CO2 and H2/H2O/CO2 at temperatures of 593–723 K and a hydrogen partial pressure of 150 kPa. Operating conditions were determined to minimize H2 loss due to the reverse water gas shift (RWGS) reaction. It was found that the feed flow rate had an important effect on hydrogen recovery (HR). Furthermore, an identification of the inhibition factors to permeability was determined. Additionally, under the selected conditions, the maximum hydrogen permeation was determined in pure H2 and the H2/CO2 mixtures. The best operating conditions to separate hydrogen from the mixtures were identified.