A Study On The Desulfurization Additive For Fluid Catalytic Cracking Gasoline

A method of immobilizing desulfuration reactive metal element to the crystalline phase was used to study the FCC gasoline desulfueration additives containing element Zn and V. Specifically, Zn was immobilized in the Zinc-Aluminate spinel and V was immobilized in the mullite to reduce the damage effect.The desulfuration rate of mullite containing vanadium was studied which was composed at a low tempreture using kaoline as raw metiarial and using impregnated ammonium metavanadate as mineralizer. Using mullite containing vanadium as desulfurate additives had not been reported by literatures. The result showed that the Microreactor Test (MAT) of the catalyst system reached71.2%and the desulfuraton rate reached44%when the ratio of mullite containing vanadium was12.7wt%, the ratio of vanadium was1.71wt%, the ratio of rare earth oxide was4wt%, the ratio of sodium was0.07wt%(at the standard of Na20) and the active silicon was removed by alkali.The Zinc-Aluminate spinel was composed using impregnation method, Sol-Gel method and coprecipitation method. The desulfuration ability of the Zinc-Aluminate spinel was studied and the deactivation mechanism of ZnO was analysed. The result showed that using Zinc-Aluminate spinel as catalytic additives, which was composed at the tempreture of800℃using impregnation method and using Zn(NO3)2as row metierial, the MAT of the catalyst system (800℃、100%vaper、4h) reached63%, the desulfuration rate reached34.8%when the ratio of Zinc-Aluminate spinel, DASY and kaoline was40:35:25. Therefore, the ZnO changed to Zinc-Aluminate spinel was not the main reason of desulfuration rate descending. It was probably because the acidic center of moleculer sieve was neutralized by the ZnO, and took the "aluminum" from the molecular sieve that caused structural failure. So the descending of desulfuration rate was mainly because of the declining of the catalyst cracking ability.