Study On Co-liquefaction Of Oil And Coal By Hydrogenation And Its Synergistic Effects

Co-liquefaction of oil and coal can not only make up for the shortage of recycling solvent for direct coal liquefaction,but also provide an effective way for the utilization of petroleum residuum,which is of great significance for the clean and efficient utilization of energy resource in China.In this paper,SM coal,FCC and DCC heavy oils were used as raw materials.The performances of SM and heavy oils co-liquefaction were studied through the single hydrogenation of coal and heavy oils,and the co-liquefaction of heavy oils and coal,combined with the characterization of product structures and compositions.Further,the synergistic effects between coal and heavy oil in the co-liquefaction process were also discussed.The results show that:(1)SM has high metamorphism,poor swelling performance and low liquefaction reactivity.The liquefaction conversion of SM in toluene is low,and the products are mainly light products such as oil and gas.In THN as a hydrogen donor solvent,the highest conversion of SM reached to 71.0%,but the yiel ds of asphaltene and preasphaltene were high.Increasing reaction temperature,reaction time and solvent /coal ratio can promote SM liquefaction to improve the conversion of SM and the yield of oil+gas.(2)The group components of FCC and DCC are mainly aromatic fraction.Meanwhile,FCC contains more aliphatic fraction,and DCC has more polar components.In the range of liquefaction temperature,the thermal stability of DCC is higher than that of FCC.At high temperature,FCC mainly produced the insoluble in n-hexane solvent(HI)via the dehydrogenation of hydrogenated aromatic components,and DCC mainly give HI by the condensation of polar components.The treatment of catalytic hydrogenation can realize the up-grading of heavy oils,in which the polar components and the formed HI are significantly reduced.However,addition of hydrogen donor solvent has no obvious effect on the catalytic hydrogenation of heavy oils.(3)Both heavy oils have good hydrogen donor capacity so that the highest conversions arrive respectively 88.5% and 89.4% for the coliquefaction of SM/FCC and DM/DCC without hydrogen donor solvent.There are good synergistic effects between SM and heavy oils in the co-liquefaction no THN used.DCC is more suitable for co-liquefaction with SM at high temperature than FCC.The addition of THN can inhibit the formation of heavy products and increase the oil+gas yield of co-liquefaction of SM and heavy oils,but it has no obvious effect on the conversion of co-liquefaction.Therefore,in view of the good synergy,the heavy oils such as FCC and DCC can replace hydrogen donor solvent for SM hydro-liquefaction.