Abstract:
Extractive distillation desulfurization of fluid catalytic cracking (FCC) gasoline coupled with hydrodesulfurization of heavy fraction was investigated. FCC gasoline was desulfurized by an extractive distillation column using propylene carbonate as solvent in a pilot device. Under optimal desulfurization conditions, light fraction distillate yield reached 63.2% with sulfur and nitrogen contents of 29.4 mg/L and 1.3 mg/L, respectively. The desulfurization and denitrogeneration efficiencies of extractive distillation process were up to 84.5% and 97.4%, respectively. The type analysis of sulfur compounds showed that propylene carbonate had high selectivity for removing sulfur and nitrogen compounds but relatively low for thiophene. Then, heavy fraction was hydrodesulfurized on a FGH 31 catalyst in a fixed bed reactor. Results showed that the mass content of sulfur and nitrogen in the heavy fraction was reduced to 9.5 mg/L and 12 mg/L with the sulfur and nitrogen removing efficiencies of 97.4% and 91.8%, respectively. Light fraction of the extracted distillation and the hydrodesulfurized heavy fraction are of primer blending compounds for producing high quality Europe IV standard gasoline.