Investigation Of Dehydrogenation Of Propane In Presence Of Oxygen

As one of the most important feedstock, propylene can be applied to many chemical processes. In recent years, its demand has increased dramatically. Propane dehydrogenation (PDH) which is an important process for producing propylene has been industrialized, but it existed the problems of high energy consumption and catalyst coking. Oxidative propane dehydrogenation and propane dehydrogenation-selective hydrogen combustion have been the hot points for their advantages in unlimited chemical equilibrium and low energy consumption. However, few study has done on the effects of oxygen concentration and the filler on the reactions.In the present study, the thermodynamics of both oxidative dehydrogenation and dehydrogenation-oxidation of propane has been analyzed and compared with that of simple dehydrogenation of propane in order to discuss about the effects of oxygen addition on the molar fraction of target product propylene and the composition of other products. The results show that for whichever propane dehydrogenation systems the addition of oxygen is extremely harmful to the production of propylene. The higher the temperature and the larger the oxygen addition amount are, the less the propylene production and the greater the feed loss will be. On the basis of that, the influences of oxygen concentration and fillers on PDH process has been investigated. It can reveal that oxygen functions together with the construct of reactor and temperature. The addition of oxygen can improve the conversion of propane and propylene in the two reactors. But in the quartz reactor, oxygen mainly joined gas-phase reaction at high temperature and the effects of oxygen concentration to the pyrolysis of propane became obviously after600℃. C3H6, C2H4, H2and CO were the main products. The propylene has a higher stability, although in the presence of oxygen. In stainless steel reactor, stainless steel reactor, oxygen mainly paiticipate in the surface catalyzed deep oxidation and coking reaction and it had an obviously effect on the reaction at low temperature. The main products were CO, CO2and H2; While silica sand can promote the conversion of propylene, it inhibits propane from reaction at high temperature. Different kinds of tar were produced on different fillers.The amount of coke generated on fumed silica was least.