Removing Sulfur Compounds from Fluid Catalytic Cracking Gasoline by Extractive Distillation

Extractive distillation method was employed for removing sulfur compounds from FCC gasoline. Firstly, the separation coefficients of gasoline and various solvents in the process of extractive distillation were determined in a modified Eliss dual-circulating vapor-liquid distiller. N-formyl morpholine (NFM) was selected as the optimal solvent. Single factor experiments were performed to obtain the optimal conditions for removing sulfur in a continuous extractive distillation apparatus. The optimal conditions were reflux ratio of 1, solvent to feed ratio of 0.7, and the distillation bottom temperature of 160 ℃ where the yield of refined oil was 64.18% with sulfur content of 26.03 mg/L and the desulfurization efficiency was up to 86.30%. PONA analysis results showed that most of olefins with high octane value were transferred to the distillate refined oil. It could be used as blending components for producing Europe IV standard gasoline.