Abstract: A sulfurizing agent was prepared by mixing sulfur with sulfided olefin, which was prepared from FCC gasoline and sulfur. Presulfided hydrofining catalysts were impregnated by this sulfurizing agent, and the effect of impregnation conditions on the sulfur content, sulfur retention rate and catalyst broken rate of the presulfided catalyst was investigated. The presulfided catalyst was activated by gas-phase batch sulfurization. Experimental results indicated that impregnation scheme by using a pre-mixing sulfur and sulfided olefin mixture with a sulfur to sulfided olefin (based on sulfur content) molar ratio of 1 was preferred. The optimum impregnation conditions were as follows: the amount of mixed sulfurizing agent should be 1.4 times of the theoretical sulfur requirement for catalyst to be fully sulfurized, impregnating at 170℃ for 3 h, the sulfur to sulfided olefin molar ratio (based on sulfur content) should be 1. Sulfur content and sulfur retention rate of presulfided catalyst added addition agent was higher than that of without addition agent. Comparison tests between in-situ and ex-situ sulfidation of catalyst were carried out on a 100 mL hydrotreating device and the results showed that the activities of catalysts by in-situ and ex-situ sulfidation were almost the same.

Key words: hydrotreating catalyst, ex-situ presulfuration, impregnation, sulfur, sulfide olefin