Abstract: The effect of presulfurization temperature (230-400℃) of MoCo/Al2O3 catalyst on its selective hydrodesulfurization (HDS) performance, such as HDS rate, hydro-saturation (HDY) rate and gasoline octane (RON) loss, was studied on a pilot plant unit using full range FCC gasoline as feed. The test results indicated that under reaction temperature of 260 ℃, with the increase of presulfurization temperature, the HDS rates of these catalysts increased from 84.4% to 91.1%; under reaction temperature of 280 ℃, the HDS rates of these catalysts were all over 96.0%, presulfurization temperature had less influence. However, in these two cases, MoCo/Al2O3 catalyst sulfurized at 250 ℃ exhibited the minimum HDY rate and gasoline RON loss, which indicated said catalyst possessed the best HDS selectivity. It was found that MoCo/Al2O3 catalyst could be well sulfurized at 250 ℃ and with less coke deposit, which would be favorable to provide good HDS selectivity when treating FCC gasoline.

Key words: Mo-Co/Al2O3 catalyst, FCC gasoline, presulfurization, hydrodesulfurization (HDS), selectivity