Pd-membrane Integration in a Propane Dehydrogenation Process for Highly Selective Propylene Production

The forecasts in the industrial chemistry field evidenced the growing demand of propylene, and the necessity to develop effective processes able to sustain the market. Selective propane dehydrogenation is emerging as the most competitive technology for the production of propylene, on the other hand, the well-known drawback closely linked to the high temperature required to reach a sustainable propane conversion and the coke formation that suppress the catalytic stability still requires appropriate solutions. In this sense, the process intensification through the combination of hydrogen permselective membranes and the reduction of operating temperature could strike the targets of very high propylene selectivity and a quite high conversion value. Since the integration of membrane units in a process required a revision of the operating conditions, the effect of feed composition and temperature was investigated, in order to determine the optimal operating parameters window to operate the system, and assess the overall concept performance. A commercial membrane was characterized, in order to understand the suitability in the propane dehydrogenation process that may cause a severe membrane deactivation due to coke deposition. Finally, specific tests on a simulated process configuration, obtained in an open architecture, confirmed that the smart combination of PDH catalytic reactors and Pd-based membranes was able to allow a reduced operating temperature, so increasing propylene selectivity, and to overcome typical thermodynamic limitations related to a traditional configuration.