Characterization And Kinetics Of Cokes Formed On Pt-based Catalyst For Propane Dehydrogenation

Propane dehydrogenation has become an important process for propene production.Pt-based catalysts shows high activity in propane dehydrogenation reactions,but they often deactivates due to coke formation,which has great influence on ecomomics of propane dehydrogenation.In this paper,Pt catalysts and Pt-Sn catalysts were prepared by incipient-wetness impregenation and compared with industrial catalysts.Spent catalysts were characterized and analynized by TGA,Raman,Prolysis GC-MS.The results showed that cokes formed on Pt-based were composed of aromatic hydrocarbons,aliphatic hydrocarbons and graphite-like materials.The length of carbon chain in aliphatic hydrocarbons ranged from C8 to C33.The decrease of acidic of supports can increase the proportion of straight-chain alkanes.Cokes had.two-dimensional sheet-like structures.The addition of Sn and K could reduce the amount of coke content and improve the graphitization extent of spent catalysts.The rose of temperature and partial pressure of propane could increse the amount of coke content and improve the graphitization extent of spent catalysts;The rose of the partial pressure of hydrogen could decrese the amount of coke content and lower the graphitization extent of spent catalysts.Analysis of kinetics of coke formation showed that the coking reaction orders to propane,propylene and hydrogen are 0.9,0.6 and-0.6,respectively.The results for coking inhibition and design of propane dehydrogenation catalysts provided some references.