Technology Research Of Olefin Reduction Of FCC Gasoline Using Ionic Liquids

FCC gasoline is about account for 80%of gasoline product in our country,which usually containing olefin 45-55%,even more than 60%.In order to reduce the olefin of FCC gasoline, Experts constantly R&D and improve the reducing-olefins technology at home and abroad. However,there still exsit some questions,such as low yield,harsh reaction condition,poor selectivity,serious pollution,complex process route and so on.Aiming at the problems,ionic liquids as a new green medium have attracted a wide spread attention,and begun the application research on the olefin reduction for FCC gasoline.In this paper,we first prepared the aluminum chloride-based ionic liquid,sulfate-based ionic liquid([Et₃NH]Cl-2AlCl₃,[Me₃NH]Cl-2AlCl₃,[Et₃NH][HSO₄],[Et₂NH₂][HSO₄]),and analyzed and characterized the density,solubility,NMR,thermal stability.We discussed in detail the optimum condition of the synthesis of aluminum chloride-based ionic liquid assisted with microwave.The results showed that the feeding mode what quaternary ammonium salt for three times,anhydrous aluminum chloride only one time is more proper.The optimum condition of the synthesis of[Et₃NH]Cl-2AlCl₃ ionic liquid:the microwave power P=320W, reaction time t=10s+10s+10s×4,the yield can reach 94.76%;the optimum condition of the synthesis of[Me₃NH]Cl-2AlCl₃ ionic liquid:the microwave power P=320W,reaction time t=10s+10s+10s×4,the yield can reach 99.04%.Microwave irradiation can significantly save the reaction time of synthesis ionic liquids and highly improve the yield compared with conventional synthesis.The ionic liquids we prepared were applied in olefin reduction for FCC gasoline in the paper.We studied several factors such as reaction temperature,reaction time,ratio of catalyst to oil,reaction press and reusability which effect the rate of olefin reduction in experiment, and analyzed the changes of PONA of FCC gasoline by gas chromatography.The best technique condition of reducing-olefin for FCC gasoline using the four ionic liquids have been determined by single factor,orthogonal experiments. 1.Under the catalysis of[Et₃NH]Cl-2AlCl₃ or[Me₃NH]Cl-2AlCl₃ ionic liquid,the optimum condition of reducing-olefin is that reaction temperature T=50℃,reaction time t=30min,ratio of catalyst to oil m_IL/m_gasoline=1:10,pressure P=0.5MPa;The rate of reducing-olefin were 85.64%,83.99%respectively,and the results were still good if reused for 4 times. In the experiments,the olefins of FCC gasoline mainly transform into isomeric alkane and aromatic hydrocarbon through hydrogen transfer reaction,isomerization,aromatization.The olefin content of FCC gasoline were 4.97%,5.54%respectively;the isomeric alkane were 53.49%,51.92%;the aromatic hydrocarbon were 23.48%,23.45%.2.The optimum condition of reducing-olefin under the catalyst of[Et₃NH][HSO₄]or [Et₂NH₂][HSO₄]ionic liquid:reaction temperature T=100℃,reaction time t=-45min,ratio of catalyst to oil m_IL/m_gasoline=1:10,atmospheric pressure;The rate of reducing-olefin(X) were 43.36%,44.50%respe- ctively,and the results were still good if reused for 8 times.The olefin of FCC gasoline mainly converted to aromatic hydrocarbon,n-alkane,i-alkane,cycloalk ane remains essentially constant.The content of olefin were 19.57%,19.21%respectively, aromatic dydrocarbon 31.64%,32.06%.