A Study On The Oligomerization Of Light Olefins Over HZSM-5 Catalyst

The environmental pollution makes it necessary to synthesize environmentally friendly liquid fuel.Light olefins oligomerization is an alternative technology and effective way to produce liquid fuel and higher-value chemical materials.Butene oligomerization reaction is the most promising technology,which converts lighter olefin cuts into vehicle fuel like gasoline and diesel and thus improves the utilization of C₄ olefin.In this work,thermodynamic of the oligomerization reaction system has been analyzed.The results indicate that,all the reactions of light olefins oligomerization to high olefins are exothermic.Olefin oligomerization reactions are reversible and limited by thermodynamic equilibrium.Increasing the temperature decreases the equlibrium fraction of C₆-C₉ and increasing the partial pressure increases the equilibrium fraction of higher olefins.The catalyst has been selected through characterization of catalyst,and found that the ZSM-5 catalyst of Si/Al=200 has the highest catalyst activity.Light olefin?C₃⁼,C₄⁼?oligomerization over HZSM-5 catalyst has been investigated under different reaction conditions and reaction pathways have been studied as well.The results show that increasing the space-time improves the catalyst activity,increases the reaction rate of cracking and decreases the selectivity of C₈.In order to get a higher selectivity of C₈,the space time should not be too long.1-Butene oligomerization is favored at lower temperature,temperature should be lower than 300?.Increasing the partial pressure increases higher olefins selectivity,improves the reaction of light olefin oligomerization.Higher olefins are also favored at higher partial pressure.