Catalytic membrane reactors for alkane dehydrogenation applications: an integration of catalysis and separation process

Catalytic dehydrogenation of saturated hydrocarbons to corresponding alkenes by the release of the stoichiometric amount of hydrogen is the paramount solution for safe storage of hydrogen. The utilization of a catalytic membrane reactor for this process enhances the reaction yield beyond thermodynamic equilibrium by selectively and simultaneously removing the produced H-2 during the reaction. To this end, the present review is focused on the integration of H-2 permeable membranes with the catalysts for dehydrogenation of lighter alkanes for coproduction of olefins and high-purity hydrogen in a single step. Besides, this review also covers dehydrogenation of liquid organic hydrogen carriers for safe storage of hydrogen. Herein, different types of H-2 perm-selective membranes used for the dehydrogenation reaction are highlighted and the effect of hydrocarbon on H-2 permeation through these membranes are discussed in detail. Furthermore, the simulation studies along with the experimental investigation performed on the membrane reactors for dehydrogenation of linear and cyclic alkanes are critically reviewed to find the coherence between simulation and experimental findings. Systematic discussion is done on the different types of alkane dehydrogenation reactions and the parameters affecting the reaction performance. Finally, directions are provided to prepare a cheaper and large industrial scale membrane reactor for dehydrogenation reaction. The concept of coupling an exothermic reaction with the endothermic dehydrogenation reaction is provided as a future direction study to enhance the overall yield and energy efficiency of the integrated membrane reactor.