Experimental Study On The Desulfurization Of FCC Gasoline Alkylation By Br(?)nsted Acidic Ionic Liquid

With the increasing awareness of environmental protection,the environmental regulations have been more and more stringent and the production of low-sulfur or sulfur-free gasoline has become the general trend of the world's clean energy.In China,environmental legislations have been imposed to restrict the sulfur content in motor gasoline to less than 50 ppm by 2014,and less than 10 ppm by 2018.Hence,it is of great practical significance to research and develop the efficient desulfurization method.In recent years,alkylation desulfurization of FCC gasoline catalyzed by ionic liquid has become the reseach hotspot,which can remove thiophene sulfur compound effectively.The reported ionic liquid primarily included Lewis acidic ionic liquid,which would easily hydrolyze and get inactivation.In the present study,several Bronsted acidic ionic liquids,which were stable to air and water,were synthesized.And a deep desulfurization method of FCC gasoline was proposed.In this study,6 kinds of Bronsted acidic ionic liquids were synthesized.Ionic liquid[BMIM]HSO4 and[BPY]HSO4 were selected as the optimum catalyst for alkylation desulfurization taking into account the desulfurization rate and yield.[BMIM]HSO4 and[BPY]HSO4 were characterized by FTIR and 1H NMR,and got test for basic property.The alkylation reaction of thiophene with ionic liquid as catalyst was studied.The reaction process included three steps.Firstly,thiophene and 1-hexene were transferred from oil phase to ionic liquid phase because of the ?-? force,then 2-hexylthiophene was produced by the alkylation reaction of thiophene and 1-hexene with HSO4-as catalyst.Finally,2-hexylthiophene returned to oil phase.The optimum condition for alkylation desulfurization of FCC gasoline,the adaptability and reusability of ionic liquid were investigated.The optimum condition for alkylation desulfurization catalyzed by[BMIM]HSO4 was 65 ?,80min and IL/oil mass ratio 0.085.The sulfur content of FCC gaoline was decreased from 580.0?g/g to 7.8?g/g with the desulfurization efficiency of 98.66%and yield of 91.30%,meeting the sulfur content of National Standard V for motor gasoline(?10?g/g).The optimum condition for alkylation desulfurization catalyzed by[BPY]HSO4 was 65?,90min and IL/oil mass ratio 0.09.The sulfur content of FCC gaoline was decreased from 580.0?g/g to 6.4?g/g with the desulfurization efficiency of 98.90%and yield of 91.27%,meeting the sulfur content of National Standard V for motor gasoline.[BMIM]HSO4 and[BPY]HSO4 could achieve high desulfurization efficiency for FCC gasoline B,FCC gasoline C and FCC gasoline D.The used ionic liquid was regenerated by extraction.The desulfurization efficiency of regenerated[BMIM]HSO4 and[BPY]HS04 exceeded 90%.The quality of FCC gasoline before and after alkylation desulfurization was discussed.The results showed that the initial boiling point,10%boiling point of FCC gasoline after reaction were elevated,50%boiling point almost remained unchanged and 90%boiling point declined slightly.The sulfur compound was converted from light fraction(<170?)to heavy fraction(>170 ?).After reaction,the FCC gasoline had a slight decline in paraffin and olefin content,had an increase in naphthene and aromatic content.The loss of MON,RON and ONI were below 1 unit.