Study On Characteristics Of Tail Oil From Hydrogenation Co-refining Of Coal And Heavy Oil Cyclic Reaction And Blending Reaction With Residue

Hydrogenation co-refining of coal and heavy oil technology owns broad developing prospects because of China's characteristics energy reserves which is rich coal and meager oil.Meanwhile,the yield of tail oil in hydrogenation co-refining of coal and heavy oil reactions were high,and utilization of that was difficult.In this paper,Anhui lignite(AH-lignite),catalytic cracking slurry(FCCS)and Venezuela atmospheric residue(MRAR)were taken as raw materials to proceed the tail oil cyclic reactions of hydrogenation co-refining of coal and heavy oil and the blending reactions with MRAR in the autoclave.In order to investigate the characteristics of the tail oil cyclic reactions and the blending reactions with MRAR,particularly,the properties of asphaltenes and solid residue were analyzed by XRD,FT-IR,XPS,SEM,thermogravimetry and so on.The results show that the composition of COAR was dominated by VGO,in which the content of bicyclic to tetracyclic aromatic hydrocarbons was higher and the content of pentacyclic aromatic hydrocarbons was relatively less.The content of aromatic hydrogen content was up to 43.85%and the alkyl side chain of hydrocarbons was shorter in COAR.Besides,the organic structure of toluene insoluble(TI)in COAR was chiefly aromatic ring,and there was obvious silicon-oxygen bond structure about the inorganic part of TI.C-C,C-H and C-O were the main surface functional group of TI,and N was mainly in the form of alkaline pyridine and pyrrole.At the same time,the content of fatty sulfur and thiophene sulfur was relatively high,and the surface tended to be alkaline.Sulfided iron and nickel in solid residue could have catalystic effect on the following reaction of COAR.The yield of light oil and solid residue were basically unchanged after 3 tail oil cyclic reactions when tail oil accounting for 35w%of the total mass in raw materials and catalyst addition is 200?g·g^-1.Meanwhile,the dispersion state of the solid particles in the product gradually becomes better with the number of tail oil cyclic reactions.The structure of asphaltene did not change much except the increase number of fat chains with the tail oil cyclic process.Coke content in the solid residue increased and the catalytically active metal accumulateed on the surface of TI with tail oil cycling.Increasing the ratio of tail oil in the raw materials to50w%,the light oil yield would be reduced,and the solid residue yield would be higher.On the other hand,the yield of light oil increase,but that of asphaltenes and solid residue would continue to increase with tail oil cyclic process when reducing the catalyst content in raw materials to 200?g·g^-1.When COAR and MRAR were blended in the absence of external catalyst,the yield of light oil was high,meanwhile,the coke was less and did not deposit in the product.The optimized reaction conditions were:50w%MRAR(accounting for total mass of raw materials),440°C,and no external catalyst.When the asphaltenes of two kind of raw materials were half to half in the blending system,the side chain of asphaltenes in the product was shorter and the degree of branching was low,which is beneficial to the stability of the reaction system.The metal in the solid residue of COAR had catalytic effect on the blending reaction.At the same time,the rough surface structure of the COAR solid residue provides a adsorption site for the macromolecular radicals in the blending system,thereby effectively suppressing the coke formation.