Preparation And Reaction Performance Of Coal Supported Catalyst In Coal/Oil Co-Processing

The coal/oil co-processing is a typical coal direct liquefaction technology,which makes the heavy oil light during the coal liquefaction.The development of dispersed catalyst with high activity plays an important role in the coal/oil co-processing.In this study,the conversion of coal based on dry-ash-free over the coal/oil co-processing was evaluated,for the different kinds of prepared coals supported by Mo,Co,Ni,Fe,and W as single active components by impregnation method.Mo was taken as the selected metal to be loaded on different coals.The effect of carrier coal characteristics on the coal/oil co-processing was examined.A coal-supported Fe/Mo bimetallic catalyst was prepared by using iron-containing and molybdenum-containing compounds,for the application in the coal/oil co-processing.The preparation conditions were optimized.And the reaction performance in coal/oil co-processing system was studied.Besides,the synthesized catalysts and products,especially the unconverted solid residue,were analyzed by using XRD,XPS,SEM,SEM-EDS,GC,GC-MS,FT-IR,particle size analysis and other characterization means,to explore the reason of catalytic activity variation.The results showed that,the order of catalytic activities for the single metal components was Mo>Co>Fe>Ni>W,with the coal A as carrier and different metals as active components of the coal-supported catalysts.With Mo as the catalyst active metal,coal A whose volatile content was the highest,exhibited a higher reactivity among various coals.The coal A was selected as the carrier,with the Mo and the Fe as the active metals(the metal weigh ratio of 5:1).During the preparation of catalysts,the iron-containing compound was first impregnated.Then add the vulcanizing agent and finally impregnate the molybdenum-containing compound.This preparation method could prevent the precipitation reaction between molybdenum-containing and iron-containing compounds,resulting in a relatively dispersed distribution of Mo on the surface of the coal.The relative content of Mo on the surface of the solid product after the reaction was also higher.The coal/oil co-processing was carried out under the reaction conditions of 3:1 mass ratio of MRAR and coal,hydrogen initial pressure of 8 MPa,reaction time of 1 h,and reaction temperature of 400°C,which reached a dry ash-free coal conversion rate of 79.12 wt%.In the coal/oil co-processing system,compared to the coal-supported Mo single metal catalyst,the gas product over coal-supported Fe/Mo bimetallic catalyst contained less methane,ethane and other light alkanes,and the liquid products were all rich in aromatic hydrocarbons.The solid product had a smaller average particle size,a rougher surface,a lower number of aromatic layers,and a lower aromaticity.The length of the fatty chain was shorter and the degree of branching was lower.The surface of the solid product tended to be alkaline.