The Study On The Mechanism Of FCC Upgrading Reaction By Cracking Catalyst For Decrement Olefin

In this paper, FCC naphtha from Binzhou and NanChong refineries wereseparated into five distillates, respectively. Then the reaction of the naphtha and theirdistillates on FCC catalyst was studied. In order to investigate the mechanism of thereaction further.The experimental results showed that without any additional hydrogen, FCCnaphtha and its distillates may get good upgrade on FCC catalyst at lowertemperatures, decreasing greatly the content of olefin in the oil. The content of olefinin the light distillates of naphtha was mush higher than that in the heavy distillates.Therefor it is a good way for upgrading the naphtha only to treat the light distillatebecause it would have less loss. The results also implied that the essential reactionsduring naphtha upgrading on FCC catalyst was olefin convertion into iso-papaffinand aromatic which may keep the octain number of naphtha constant, even a little ofincrease. Small olefin molecules (≤C₆) may convert into aromatics besidesiso-papafins. It indicated that during this process, the small olefins oligomerize firstand then aromatize, hydro-transfer or crack. Whereas the larger olefin (＞C₆)molecules mainly crack first into small ones and then react as mentioned above forthe small olefins.