The Investigation On The Oxidative Dehydrogenation Of Propane To Propylene

Propane dehydrogenation process is divided into oxidative dehydrogenation process and direct dehydrogenation process. The propane direct dehydrogenation to propylene has realized the industrialization, but it is difficult to raise the conversion of popane as a result of a thermodynamic balance limitation. And catalyst consumes lots of energy because of deactivating rapidly and regenerating frequently.Propane oxidative dehydrogenation of the lower temperature exothermic reaction replaces the high temperature endothermic reaction, so which can greatly reduce energy consumption.Due to thermodynamic balance limitation, the reaction can proceed without carbon deposition of catalyst. So it can avoide regeneration frequently,and reduce equipment investment. Therefore the development of high activity and high selectivity of the catalyst for propylene is the bottleneck problem in the research range,and has become a heat subject in recent years.At present, highly selective catalyst for propane oxydehydrogenation has not developed. So catalyst for oxidative dehydrogenation of propane to propylene is researched in this paper. And three series catalysts for oxidative dehydrogenation of propane to propylene are developed, to get product of high selectivity and percent conversion.In this paper, we discuss the progress of research on propylene, analyze advantages and disadvantages of production method of propylene, introduce production method of oxidative dehydrogenation of propane to propylene. Then the common catalysts for propane oxidative dehydrogenation to propylene are introduced. Meanwhile a new way of synthesis catalyst is advanced. The catalyst consists of three series: W-Ce-O catalyst, Mo-Ce-O catalyst and VPO catalysts.W-Ce-O catalyst for propane oxidative dehydrogenation still has not been reported. The W-Ce-O catalyst is used firstly in propane oxidative dehydrogenation to propylene. And we research on effect of the preparation method,the loading amount,the reaction conditions and the W/Ce on the performance of the catalyst for W-Ce-O catalyst. The result shows that this series of catalysts have certain low-temperature catalytic capability for propane oxidative dehydrogenation to propylene. However, there still is a certain distance from realizing industrialization. The Mo-Ce-O catalyst is researched in this paper. The MoCexOy (x=0.05, 0.1,0.15,0.2,0.25,0.3) catalysts are produced by pickling process. And then research on the effect of the loading amount,the reaction conditions, the Ce/Mo on the performance of the catalyst for Mo-Ce-O catalyst. Meanwhile, we research on the effect of the synthesis conditions (calcination temperature,calcination time) of catalyst on the performance of the catalyst for Mo-Ce-O catalyst. This series of catalysts have good low-temperature catalytic capability for propane oxidative dehydrogenation to propylene.To further perfect catalysts system of propane oxidative dehydrogenation, the VPO catalysts are initially researched in the paper.A new preparation method for VPO catalyst is advanced. The catalyst is produced by vanadium pentoxide and phosphoric acid by using coprecipitation synthesis, and with the addition of oxide of cerium zirconia material. In addition, the catalytic activity was examined. The test results show that the catalysts have not good catalytic capability for propane oxidative dehydrogenation to propylene.In addition, a unsteady state experimental equipment of fixed bed reactor is set up as the reactor of propane oxidative dehydrogenation to propylene in the experimentation,according to characters of artificial unsteady state and reaction of propane oxidative dehydrogenation to propylene. Comparing with experimental equipment of mixing of propane and air, the oxygen, nitrogen, propane feeding respectively is achieved . Meanwhile making the propane oxidation (the catalyst reduction) and the catalyst oxidation at different times is realized. To enhance selectivity of the target product and reduce deep oxidation, the lattice oxygen oxidation of catalyst is used for oxidation of propane in the experimentation. It is difficult to realize research on selective oxidation of propane by circulating fluidized bed reactor in the lab. Because it is not only complicated, but also requiring the catalyst with good fluidifying performance. But in the technology, catalyst experiences cyclical reductive atmosphere and the oxidizing atmosphere in fixed bed reactor.So it is similar to technology of circulating fluidized bed.Therefore, it can simulate the reaction relevant parameters of the circulating fluidized bed process by the unsteady state experimental equipment of fixed bed reactor.And it is simple, suitable for preliminary study.