Catalytic Oxydehydrogenation of Propane and Butane Under Free-of-Oxygen Atmospheres

This review examines the state-of-the-art in catalytic oxidative dehydrogenation of propane and butane to olefins under oxygen-free gas-phase conditions (FOx–PCODH and FOx–BCODH). First, it is compared with traditional methods for C3–C4 olefin production, using reaction enthalpies as an indicator of the process energy required. The role of catalyst oxygen species, including lattice and chemisorbed oxygen, is discussed in relation to olefin formation under oxygen-free gas-phase operation. This is followed by a review of V2O5-based catalysts, with particular emphasis on co-catalysts and catalyst supports. The performance of V2O5-based catalysts for FOx–PCODH is assessed using overall olefin formation rates. Special attention is given to catalyst performance in the mini-fluidized CREC Riser Simulator, which exhibit the highest overall olefin formation rates. These studies are also valuable to shed light into the FOx–PCODH reaction mechanism and to determine paraffin conversion, olefin selectivity, oxygen availability, and coke formation. This data can be used to determine FOx–PCODH kinetic parameters by assessing the effects of temperature, contact time, paraffin partial pressure, and catalyst-to-feedstock ratio. Finally, this review analyzes Barracuda-based numerical simulations of a large-scale downer reactor using statistically derived kinetic parameters. These simulations are employed to confirm the viability of the FOx–PCODH process at an industrial scale.