Modeling of propane dehydrogenation combined with chemical looping combustion of hydrogen in a fixed bed reactor

A redox process combining propane dehydrogenation (PDH) with selective hydrogen combustion (SHC) is proposed, modeled, simulated, and optimized. In this process, PDH and SHC catalysts are physically mixed in a fixed-bed reactor, so that the two reactions proceed simultaneously. The redox process can be up to 177.0% higher in propylene yield than the conventional process where only PDH catalysts are packed in the reactor. The reason is twofold: firstly, SHC reaction consumes hydrogen and then shifts PDH reaction equilibrium towards propylene; secondly, SHC reaction provides much heat to drive the highly endothermic PDH reaction. Considering propylene yield, operating time, and other factors, the preferable operating conditions for the redox process are a feed temperature of 973 K, a feed pressure of 0.1 MPa, and a mole ratio of H2 to C3H8 of 0.15, and the optimal mass fraction of PDH catalyst is 0.5. This work should provide some useful guidance for the development of redox processes for propane dehydrogenation.