Roles of Pt and alumina during the combustion of coke deposits on propane dehydrogenation catalysts

Temperature programmed oxidation of coke deposited on Pt based propane dehydrogenation catalysts reveals that the deposited coke can be categorised into three groups according to their burning temperatures. When coke was separated from the catalyst, however, only one TPO peak could be observed. Experimental results suggest that γ-Al₂O₃ enhances the coke burning process by increasing coke surface area contacts to oxygen. Pt may also act as a catalyst for the coke combustion reaction. Experiments also show that changing dehydrogenation reaction temperature, variation of H₂/HC ratios, addition of only Sn or Sn and an alkali metal (Li, Na and K) can significantly affect the amount of each coke formed. Sample weight used in the temperature programmed oxidation (TPO) experiment also affects the resolution of TPO spectrum.