Technological Conditions Optimization Research Of Coal And Heavy Oil Hydrogenation Co-processing

The coal and heavy oil hydrogenation co-processing can achieve the liquefaction of coal and the weight reduction of heavy oil simultaneously.The process utilizes the synergistic effect of coal and heavy oil,under the action of dispersed catalyst and high-pressure hydrogen atmosphere.Compatibility of coal and heavy oil,type of catalyst,as well as the reaction parameters are the key factors to the co-treatment process.Therefore,in this paper,the technological conditions research was taken as the main line.Control variable method was adopted to investigate the effect of different coal and heavy oil,type of catalyst,and the influence of the reaction temperature and time,as well as the hydrogen conditions.In the meantime,the effect of various factors on the co-processed reaction products were compared by orthogonal design method.In addition,the structure and composition of asphaltene,preasphaltene and tetrahydrofuran insolubles were characterized by multiple inspection analysis,such as SEM,FTIR and TGA.In order to understand the coal/heavy oil hydrotreating cotreatment process from a microscopic perspective.The results showed that it was suitable to employ the lignite coal,which with high volatile matter(>40wt%)and low ash(<10wt%)content.The fluid catalytic cracking slurry,possessed excellent flowability,strong aromaticity and less heavy components,was suitable as feed oil.The coal powder content should not exceed 42wt%,while excessive coal lead to a reduction in vacuum distillate.Depending on the conversion effect of three different catalysts,an oil-soluble iron-nickel catalyst was preferably used for the co-refining reaction of coal and heavy oil.In the initial stage of the co-processing reaction,the product still contained much unconverted coal.With the increase of the severity of the reaction,the liquefaction velocity of the coal was accelerated.The pre-asphaltene and tetrahydrofuran insolubles decreased with the increase of reaction time.And the yield of asphaltene and oil reached the maximum when the reaction time was 60 min.When the reaction temperature was above 440 ? or the reaction time exceeded 120 min,the yield of gas,asphaltene and pre-asphaltene was increased.Once the condensation reaction of liquefied oil began,the oil yield and the conversion rate of dry-base ash-free coal were cut down.According to the results of orthogonal calculation,adequate catalyst and hydrogen radicals promoted the conversion of coal radicals to pre-asphaltene,asphaltene,and then the oil phase.And the appropriate reaction severity could ensure the highest yield of light oil and vacuum distillate,as well as affecting the fluid properties of the products.The well-converted co-processing products had fine coal particles,good light transmittance,low viscosity and excellent flow properties.During the reaction,the coal particles were pyrolyzed,and then collapsed and deconstructed gradually.The tetrahydrofuran insoluble matter continuously moved to the pre-formation asphaltene and asphaltene,with the saturated alkanes reduced,the polycyclic aromatic hydrocarbons and oxygen-containing substances increased.The amount of pyrolyzable substance in the liquefaction residue was continuously reduced.The excessively high reaction severity caused the condensation reaction.The temperature of the weight loss peak in the 700-800? section increased,which has a strong positive correlation with the Conversion of dry ash-free coal.