Assessment of the desulfurization of FCC vacuum gasoil and light cycle oil using ionic liquid 1-butyl-3-methylimidazolium octylsulfate

Increasingly stringent fuel sulfur content requirements/legislations have resulted in intensive quest for alternative desulfurization technologies that will ensure the treatment of fuels to acceptable sulfur levels. In this regard, the extraction of sulfur compounds from gasoline and diesel oil by ionic liquids (ILs) may represent a green alternative to common hydrodesulfurization for deep desulfurization (10 ppm sulfur). This paper investigates the extraction efficiency as well as the regeneration of the IL, 1-butyl-3- methylimidazolium octylsulfate ([BMIM][OcSO4]) for the desulfurization of the fluid catalytic cracking diesel fuels. The IL was found to be effective in the selective removal of sulfur from FCC light cycle oil than from the FCC vacuum gasoil stream, achieving 96 and 22.1% sulfur removals, respectively. These results suggest that fuel sulfur content and stream composition affects the extraction efficiency and effectiveness of IL. In addition to the fundamental experiments with FCC diesel fuels, the regeneration of sulfur loaded ILs was studied and a preliminary strategy for theintegration of an IL-extraction process into an existing refinery structure is briefly discussed. Regenerated [BMIM][OcSO4] IL was used for desulfurization of diesel and achieved highest sulfur removal of 95%. The IL was regenerated up to four times without appreciable decrease in efficiency. The results obtained herein show that ILs may beeffective in the desulfurization of real diesel oils.