Study On The Comprehensive Utilization Of Ethylene Tar

Ethylene tar is the high temperature condensation product of raw materials and products in the steam cracking process of ethylene cracking raw materials,and its output is about 10～15%（wt）of ethylene output.It has the characteristics of high content of C and H elements,low content of S,N and O elements,almost no ash and no metal impurities.Ethylene tar contains a large number of aromatic compounds,and black smoke produced by direct combustion will lead to environmental pollution.In addition,there are many important raw materials of organic chemical products in ethylene tar,which will also cause waste of resources.At present,the utilization of ethylene tar is mainly divided into heavy components and light components.Heavy components can be used to prepare high-quality needle coke,mesophase pitch and carbon fiber,while light components can be used to prepare important organic chemical products and high-quality light and heavy aromatic solvent oil and fuel oil.However,most of the existing development and utilization of ethylene tar are only used to prepare one or several products,and there is no need to realize integrated and comprehensive utilization of ethylene tar.At present,there is not a perfect technology and the development depth is not enough for the existing project of integrated utilization of ethylene tar industry.In this paper,the comprehensive utilization of light and heavy fractions obtained after distillation of ethylene tar and the change of properties of light and heavy fractions after polymerization were explored,and finally the integrated comprehensive utilization process of ethylene tar was determined to improve the comprehensive utilization degree of ethylene tar.In this paper,the basic properties of ethylene tar in Daqing Petrochemical Company were evaluated,the basic physical and chemical properties of ethylene tar were determined,and the distillation range and carbon number distribution of ethylene tar were analyzed by high temperature simulated distillation chromatograph.Then the ethylene tar raw material is rectified and cut to obtain IBP～200℃,200～230 ℃,230～250 ℃,250～290 ℃ and ≥ 290 C fractions respectively.Impregnating asphalt was obtained by thermal polymerization of ≥ 290 C fractions,and the best conditions of thermal polymerization were determined.Petroleum resin was obtained by polymerization of IBP～200 ℃ fractions.Finally,by analyzing and measuring the properties of polymerized IBP～200 ℃ and 250～290 ℃ fractions,they meet the properties of light aromatic solvent oil and high boiling aromatic solvent oil respectively,so they can be used to prepare aromatic solvent oil.Naphthalene with purity of99% was prepared from 200～230 ℃ fraction by melt crystallization.This method is simple and easy to operate.230～250 ℃ fractions can be used to prepare rich solution of methylnaphthalene by rectification,which provides high-quality raw materials for preparing methylnaphthalene.Impregnator asphalt can be prepared by thermal polymerization and vacuum distillation of heavy fractions ≥ 290 C,which meets the national standard of coking impregnant asphalt.Therefore,this study solves the defects of low utilization rate and single utilization mode of ethylene tar,expands the sources of some basic organic chemical raw materials,improves the utilization rate of ethylene tar,and provides basic theoretical support for the comprehensive and integrated utilization of ethylene tar by related oil enterprises.