关键词: 汽油, 催化裂化, 烯烃, 干气, 乙烯

Abstract: The effect of gasoline group compositions on the formation of dry gas in FCC process was investigated using a fixed-fluidized bed reaction unit and MMC-2 catalyst. Results show that in the FCC process dry gas is mainly produced by catalytic cracking reactions, the percentage of dry gas formed by thermal cracking is low. With the increase of olefin content in gasoline feedstock, the ethylene yield increases significantly, yet the yields of hydrogen, methane and ethane remain almost unchanged. The dry gas components, hydrogen, methane, ethane and ethylene, are produced during the scissions of penta-coordinated carbonium ions formed by the protonation of paraffin. Ethylene could also be produced by the β-scissions of tri-coordinated primary carbonium ions formed by the protonation of olefin. The ratio of theβ-scissions of the primary carbonium ions and theβ-scissions of the secondary carbonium ions formed by the isomerization of primary carbonium ions is fixed.

Key words: gasoline, catalytic cracking, olefin, dry gas, ethylene