Performance Analysis of a Porous Packed Bed Membrane Reactor for Oxidative Coupling of Methane: Structural and Operational Characteristics

The performance of the Oxidative Coupling of Methane (OCM) reactions in a porous ceramic packed bed membrane reactor was experimentally investigated using an Mn–Na2WO4/SiO2 catalyst. A novel practical method was applied to modify the available commercial α-alumina membrane and shape it to the form of an inert fine oxygen distributor in an OCM membrane reactor. The characteristics of such modified membrane and the performance of the resultant OCM membrane reactor are reviewed in this paper. It was observed that establishing a 2 bar pressure gradient across the modified membrane ensures a safe and efficient oxygen-dosing along the OCM membrane reactor. Moreover, using a modified membrane with a descending permeation profile instead of a uniformed permeation profile improved the observed C2 selectivity (ethylene and ethane) by 10% in average. The efficient design of the membrane reactor setup and the stability of the prepared catalyst provided a robust operation and replicable results. In this experimental analysis, a very promising 25.5% C2 yield and 20.3% ethylene yield with 66% C2 selectivity were achieved under very low (20%) diluted reaction atmosphere for the methane-to-oxygen ratio 2. By proper exploiting the carbon dioxide instead of nitrogen dilution, the C2 yield was improved by 1–2% in average.