Study On The Compatibility And Reaction Behavior With Hydrogen Of Coal Tar/Heavy Oil Mixed System

With the aggravation of crude oil and the tendency of inferior quality,the efficient utilization of heavy petroleum resources has become an important issue to be solved urgently.Co-processing of coal tar and heavy oil is an important research direction in heavy oil processing technology.Therefore,through the research on the sediment flocculation and compatibility problems of coal tar/heavy oil mixed systems,and the coking problem of reaction with hydrogen in the mixed systems,it could provided the theoretical basis for the development and application of slurry bed process technology.In this paper,the Yulin low temperature coal tar and Venezuela heavy oil as feedstocks were matched into the mixed systems of different coal tar content.The reaction behavior with hydrogen of coal tar/heavy oil mixed systems under dispersive catalysts was investigated in the autoclave.Using elemental analysis,H-nuclear magnetic resonance?¹H-NMR?,vapor pressure osmometry?VPO?,small angle X-ray scattering?SAXS?,thermogravimetric analysis?TGA?,scanning electron microscope?SEM?,transmission electron microscope?TEM?,X-ray photoelectron spectroscopy?XPS?,X-ray diffraction?XRD?,improved B-L method and other methods,the compatibility of mixed systems and the composition and structure characteristics of C7-asphaltene were studied.And further the influence of the polar components of coal tar on the coking behavior of reaction with hydrogen in the mixed systems was investigated.The reaction with hydrogen of coal tar/heavy oil mixed systems under dispersive catalysts was studied.The results showed that the coal tar with poor quality and high asphaltene content could effectively improved the hydrogenation performance and products distribution of mixed systems.Compared with coal tar and heavy oil,the products distribution of mixed systems in reaction with hydrogen showed that the tail oil?>360°C fraction?yield was effectively decreased,the gasoline and diesel oil yield were increased,and coke yield was increased slightly.The C7-asphaltenes chemical characteristics of coal tar/heavy oil mixed systems were studied.The results showed that when the mixed systems with coal tar content for 10 wt%³0wt%,the asphaltenes of mixed systems showed that the content,the average relative molecular mass,the naphthenic ring number and aromatic ring number of molecular structure and the aromaticity increased.Coal tar asphaltenes?CT-asp?and heavy oil asphaltenes?M-asp?easily formed the larger association size of asphaltenes micelles.When the mixed systems with coal tar content for 40 wt%¹00 wt%,the asphaltenes of mixed systems showed that the content and the aromaticity increased,but the average relative molecular mass,the naphthenic ring number and aromatic ring number of molecular structure reduced.The relative mass fraction of the asphaltenes micelles formed by two type asphaltenes association decreased,so the average micelle size of asphaltenes in mixed systems reduced.The hydrogen bonding interaction of heteroatomic functional groups caused the asphaltenes association between CT-asp and M-asp,the association aggregation degree depends on the amount of substance ratio(n _CT-asp/n _M-asp)and their molecular chemical composition and structure characteristics.The effect of coal tar polar components on the reaction behavior with hydrogen in coal tar/heavy oil mixed system especially the coking behavior was studied.The results showed that the coal tar asphaltenes in reaction with hydrogen was mainly converted into high aromaticity aromatics,resins and secondary asphaltenes,and less coke content,compared to heavy oil asphaltenes.The effect of coal tar native toluene insolubles on mixed systems was derived from inorganic mineral composition The iron oxides in coal tar inorganic mineral were conerted to Fe_1-xS in the reaction with hydrogen,forming the multi-metal catalysts system with Mo-Ni catalysts,which had the double function of inhibiting coke and catalytic hydrogenation in the mixed systems.The aggregation of CT-asp and M-asp in mixed systems was the main source of the coke.The coking behavior of asphaltenes aggregation depended on the amount of substance ratio(n _CT-asp/n _M-asp).The reaction with hydrogen of mixed systems was poorer with the amount of substance ratio(n _CT-asp/n _M-asp)in the range of 10 to40,and the mixed systems generated more coke content.Further,the research proved that the coking process in mixed systems was the forming process of the coke particles and then the growing and crosslinking of coke particles.The added asphaltenes dispersant could inhibit the growth and coalescence of coke particles.