Ultra-thin (~1 μm) Pd–Cu membrane reactor for coupling CO2 hydrogenation and propane dehydrogenation applications

Abstract

Coupling of dehydrogenation reactions (propane dehydrogenation) and CO2 hydrogenation reactions in a membrane reactor has synergetic effect on the overall performance of the reactor. In this context, an ultra-thin (~1 μm) Pd57Cu43 wt% alloy membrane was explored as a H2 permeable membrane for integrating both the reactions. The membrane was synthesized by electroless plating method inside Al2O3 hollow-fiber substrate. The membrane showed high H2 permeance of 7.2 × 10-4 molm-2s-1Pa0.55 at 500 °C and an excellent thermal cycling stability for five repeated cycles. Pd–Cu alloy membrane was found to have a stable performance in presence of C3H6 compared to metallic Pd membrane. This is attributed to the weaker interaction of C3H6 with the Pd–Cu compared to Pd, as confirmed from FTIR analysis. CO2 hydrogenation reaction was carried out in a catalytic membrane reactor (CMR) using Pd57Cu43 wt% membrane and 10% Ni/CexZr1-xO2 catalyst. H2 was supplied to the catalyst through the membrane using synthetic gas mixture of C3H6, C3H8 and H2 in the feed side. The conversion of CO2 in the CMR was found to be increased from the conventional reactor and the H2 recovery was also enhanced in the CMR.