Oxidative Dehydrogenation Of Propane To Propylene Over Supported Vanadium Catalysts

Propylene is a basic raw material for petrochemicals, which mainly used to produce acrylic, acrolein, alcohol, acid, anhydride, acrylic, etc. With the rapid growth of demand, the conventional processes for producing propylene are difficult to meet the actual demand. Though the reaction of propane dehydrogenation to propylene has been industrialized, but consumed a lot of energy because of it is endothermic and required high-temperature, and propane oxidative dehydrogenation is exothermic under low temperature, which the energy can be saved greatly. Therefore, it is great significance to develop a catalyst with high selectivity and activity for propane oxidative dehydrogenation.The V/? and V/?-Al2O3 catalysts were produced by immersion process in this paper, in order to obtain higher selectivity, we modified the catalyst that had better catalytic activity in above and V/? and V/?-Al2O3 catalysts with different magnesium content were prepared. The catalysts were characterized by XRD, BET, H2-TPR, NH3-TPD, UV-Vis DRS and FT-IR,and the catalytic properties of the catalysts for propane oxidative dehydrogenation have been investigated. The adsorption of propane and propylene and their changes in temperature programmed were investigated by in-situ infrared spectroscopy, the adsorption process of propane and propylene on the molecular sieve were simulated with simulation software. The experimental results show that:1.The activity of 8V/? and 8V/ ?-Al2O3 with V loading of 8wt% are better at 500?.2.The activity of 8V4Mg/? catalyst with Mg loading of 4wt% is good, the selectivity of propylene is 71.2% and the conversion of propane is 17.2% at 500 ?.3.The adsorption process of propane on ?-zeolite, 8V/? and 8V4Mg/? catalyst at 50, 500? was studied by in-situ infrared spectra. At the same time, propane and propylene were studied in 8V/?, 8V/?-Al2O3, 8V4Mg/? and 8V4Mg/?-Al2O3 catalysts were investigated. In situ FTIR spectra showed that the addition of vanadium was beneficial to the adsorption of propane on the catalyst. The in situ FT-IR spectra of propane and propene on the catalyst showed that the alkali metal Mg favored the selectivity of propylene.4.The adsorption of propylene on the mesoporous molecular sieve is more than propane. The self-diffusion coefficient of propane decreases with the increase of the adsorption capacity. When V2O5 reacts with propane?propane and oxygen, finally propylene is formation with different reaction processes.