| The issues of efficient and green conversion of petroleum resources and clean fossil liquid fuels production technology is of very importance to the sustainable development of China. The concept of molecular level management of refining and the atom economy of chemical engineering drives the research and development of new technologies for producing clean fuels which meet Euro IV and Euro V emission standards.Based on the concept of molecular management of light oils, extractive distillation method was employed for removing sulfur compounds from FCC gasoline in this work. At first, a modified Eliss dual-circulating vapor-liquid distiller was used to select the best solvents among 13 candidate solvents, including sulfolane, propylene carbonate(PC), N-formyl morpholine(NFM), N-methyl pyrrolidone and etc. By testing vapor-liquid equilibrium data of gasoline and solvent, the extractive distillation separation coefficients of various solvents were calculated, which were used to select suitable solvents for the extractive distillation process. As their fair removing sulfur results, NFM and PC were selected for further investigations.Single factor experiments were carried out for obtaining the optimal conditions for removing sulfur with two solvents on a continuous extractive distillation apparatus. The optimal conditions of NFM were reflux ratio 1, solvent to feed ratio 0.7 and the distillation bottom temperature 160℃. The yield of refined oil reached up to 64.18v%, sulfur content 26.03 mg·L-1, desulfurization efficiency 86.30%. The optimal conditions of PC were reflux ratio 1, solvent to feed ratio 1 and the distillation bottom temperature 150℃. The yield of refined oil reached to 63.18v%, sulfur content 29.43 mg·L-1, desulfurization efficiency 84.47%, nitrogen content 1.31 mg·L-1. Low sulfur gasoline obtained above meet the standards of Euro IV gasoline, and PC has a better denitrification effect compared with NFM. PFPD chromatograms showed that the two solvents could remove most of sulfur compounds from FCC gasoline effectively. However, thiophene is difficult to be removed and the two solvents all showed low selectivity of thiophene. NFM solvent could decrease thiophene content decreased from 63.17 mg·L-1 to 29.14 mg·L-1, while PC from 63.17 mg·L-1 to 25.51 mg·L-1. PONA analysis results showed that most of olefins and iso-paraffin were transferred to the distillate refined oil, while most of aromatics were extracted and normal and cyclic paraffins have a little bit growth.Aspen Plus was employed to simulate the extractive distillation process by using RadFrac distillation model. According the real components in the gasoline, the extractive distillation was simulated using PC as solvent. Reflux ratio, solvent to oil ratio and stages were investigated. The results showed that the reflux ratio affected greatly on the thiophene content in the distillate, while solvent to feed ratio had a slight effect. Sulfur content doesn't change when the stage number reached up to 30 and above. The optimal conditions were 30 total stage, reflux ratio 0.4 and solvent to feed ratio 1. The distillate yield could reach up to 57.27m% and 61.95v% with 52.47μg·g-1sulfur content. The simulation results were fairly coincided with the experimental results.
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