Preparation Of Mesophase Pitch Using Anthracene Oil Extract Of Direct Coal Liquefaction Residue

Direct coal liquefaction residue is a mixture of high carbon,high ash,high sulfur and high calorific value^[1-2]produced in the process of direct coal liquefaction,which has high potential utilization value.Converting it into high value-added products not only improves the utilization rate of raw materials,but also plays a great role in environmental protection improvement.In this thesis,by analyzing the basic composition and properties of direct coal liquefaction residue（DCLR）and investigating the optimal process conditions for the preparation of mesophase pitch.Mesophase pitch was prepared by solvent extraction and co-carbonization.The residue was divided into toluene insoluble substance（TI）and toluene soluble substance（TS）by solvent extraction method,and the effects of adding silicone oil as dispersant and viscosity reducer on mesophase pitch structure of TS component were also investigated.Cocarbon principle is to enrich the composition of raw materials by proportioning oil.The cocarbon raw material selected in this paper is Karamay Catalytic oil slurry（SLO）in Xinjiang.In the experiment,mesophase pitch was prepared by direct heat condensation method.The thermal polymerization device consisted of tin bath heating furnace,nitrogen,intelligent temperature programmed system,back pressure valve and reaction vessel.The conditions examined included reaction temperature（420-500℃）and constant temperature time（6-10h）.The structure difference of mesophase pitch was evaluated by polarizing statistics,XRD diffraction,Raman and resistivity measurement.The optimum reaction conditions were determined to be 450℃-0.8 MPa-10h,and it was found that compared with DCLR condensation product,the content of mesophase and the proportion of basin structure in mesophase were increased by 17.3%and 18.5%respectively,and the structure of mesophase was improved greatly.The mesophase pitch structure obtained from different proportions of raw materials was investigated in the co-carbon method.The optimal ratio of SLO and TS was 1:4.Under this ratio,mesophase content increased39.2%compared with DCLR condensation product,and the proportion of basin structure increased 39.4%.At the same time,the the compositions of gas phase,liquid phase and solid phase of raw materials DCLR,TS and SLO-TS-1/4 in the reaction process were discussed to explore their variation trend and understand their role in the formation of mesophase.