Study On The Reaction Of Butane Catalytic Dehydrogenation And Catalyst Carbon Deposit

In this paper, dehydrogenation of isobutane to isobutene was carried out over Cr/Al₂O₃ catalyst in fixed bed micro-reactor. The main research included three parts which were the dehydrogenation of mixed butane to butene, the kinetic of isobutane dehydrogenation to isobutene and the factors of formation coke on catalyst.?1? The effects on the conversion of butane and the selectivity to butene were studied,such as reaction temperature, liquid hourly space velocity?LHSV? and material composition. The results showed that the Cr/Al₂O₃ catalyst showed high activity for mixed butane dehydrogenation. When the content of n-butane was between 100?4??w? and 40?4??w?, the optimal reaction temperature was 540? and the optimal LHSV was 2.5h^-1, the conversion of mixed butane was above 30?4? and the selectivity to butene was above 80?4?.When the content of n-butane was below 40?4??w?, the optimal reaction temperature was540?⁵60? and the optimal LHSV was 2.0h^-12.5h^-1, the conversion of mixed butane was between 30?4? and 45?4? and the selectivity to butene was above 90?4?.?2? To omit the effects of internal and external diffusion, different experiments have been done at several particle sizes and catalyst amounts respectively to choose the suitable range for kinetic study. The parameters of the kinetic model were worked out using Matlab:The suitable conditions were obtained, the range of temperature was 500?⁶00?, the range of pressure was 101.32 k Pa¹013.2k Pa and the range of LHSV was 1.5h^-13.5h^-1.?3? The factors on the amount and type of coke formation on catalyst was studied which were reaction temperature, reaction time and content of isobutene in feed. The results showed that the amount of isobutene?0⁵0%? showed greater influence on carbon deposition, the reaction temperature?500?⁶00??was mediate, and the reaction time ?2¹5 h? was relatively low. There was only the soft carbon deposition when the amount of isobutene and the reaction time were changed. But hard carbon deposition was formed with the extended reaction time. According to the SEM image of Cr/Al₂O₃ catalyst,no obvious massive carbon deposit was observed on the surface of catalyst. And there was no accumulation phenomenon between catalyst particles.