The Research Of Effects Of Olefin Composition On Octane Number In FCC Gasoline By Gas Chromatography

With the continuous strengthening of global environmental regulations,the olefin content requirements in gasoline are more and more stringent.The production of gasoline in China is characterized by that FCC gasoline accounts for more than 80% of the total amount of vehicle gasoline,while the olefin content in FCC gasoline is high with a volume fraction of 40% ?60%.Clean gasoline,therefore,the main direction of research is to reduce the olefin content of FCC gasoline and high octane number,the current research mainly focus on reduce the effects of total olefin content in FCC gasoline,and reduce the octane number of problems have not been fundamentally solved,so the different distribution of olefins and structure on the influence of catalytic cracking gasoline octane number is very meaningful.In this paper,the influence of different olefin distribution and structure on octane number of FCC gasoline was studied by gas chromatography and multidimensional gas chromatography.The standard method for determination of octane number and composition of FCC gasoline by gas chromatography was established.The method has the characteristics of less sample injection,simple operation,quick analysis and high precision.In the determination of hydrocarbon composition in FCC gasoline,the contents of straight-chain alkanes,branched alkanes,olefins,cycloalkanes and aromatics can be determined.The deviation of repeated determination of hydrocarbon composition is no more than 3%.The octane number of FCC gasoline has been repeated with a deviation of 0.5 units.The method is only applicable to the catalytic cracking gasoline produced by catalytic cracking reaction in Lanzhou petrochemical catalyst unit and laboratory small catalytic cracking test unit.Octane number ranges between 88-95.A comparative test between gas chromatography and multi-dimensional gas chromatography was completed,which provided a scheme for studying the influence of different olefin distribution and structure on octane number of FCC gasoline.Finally,the research results are as follows: for FCC reaction,the more branched chains of olefins,the more olefins distributed in C4-C7,and the more positive effects on octane number.