Study On Coal/Oil Co-Processing Based On Coal Classification And Utilization

Taking coal as the main body of my country’s energy supply is an objective choice for my country’s fossil energy resource endowment.With the rapid development of my country’s economy,the demand for liquid fuels is increasing day by day,and coal-based liquid fuels have become a hot spot in relevant basic research and industrial demonstrations.Coal/oil coprocessing technology is a new type of coal-to-oil technology that combines direct coal liquefaction and heavy oil processing technology.This technology not only converts coal into liquid fuel,but also promotes the processing and utilization of heavy oil.Selection is the main technical barrier restricting the stable operation,popularization and application of this technology.Based on this,our research group proposed a coal liquefaction method based on the maceral composition characteristics of coal and rock.The selection range of coal and oil samples can be expanded and the efficiency of coal/oil co-processing can be improved by prequalizing coal samples and replacing co-processing with coal pyrolytic tar partly or entirely.Under the guidance of this concept,this study took Shaanxi Yanchang coal as the research object,and carried out a single mass separation experiment of 5 kg raw coal by using heavy liquid floatation and sedimentation separation method.High purity maceral-enriched coal samples were obtained,and their structural characteristics were systematically analyzed.Furthermore,the reaction characteristics of maceral-enriched coal sample and FCC slurry coprocessing were investigated,and the composition and distribution of the products were studied.The interaction between maceral-enriched coal and FCC slurry was investigated by separate hydrogenation experiments.On this basis,the reaction characteristics of coal tar and vitrinite enriched coal pyrolysis as co-refining and vitrinite enriched coal were investigated.The specific research content is as follows:Study on macro separation of coal macerals: Based on the previous research of the research group,a single mass separation experiment of 5 kg raw coal was completed by heavy liquid float and sink separation method,and vitrinite,inertinite and mineral-enriched coal samples were obtained by mass separation of raw coal.Among them,the vitrinite content in the vitriniteenriched coal increased from 48.05% of the raw coal to 76.02%,the inertenite content in the inertinite enriched coal increased from 43.96% of the raw coal to 63.98%,the mineral content of the mineral-enriched coal increased from 6.23% to 61.99% of the raw coal.Study on the reaction characteristics of microcomponent enriched coal and FCC oil slurry co-processing: Vitrinite-enriched coal have high hydrogen-to-carbon atomic ratio,high volatile content,and high oxygen content.In the coal/oil co-processing reaction,the gas and liquid product yields are high,the coal conversion rate is high,the hydrogen consumption is low,the product oil quality is good,and the aliphatic hydrocarbon content is high.Inertinite enriched coal has high graphitization degree,stable aromatic structure and high condensation degree.Therefore,in the coal/oil co-processing reaction,the gas yield,liquid yield and coal conversion rate are all low,the coke yield is high,the hydrogen consumption is large,the aromatic hydrocarbon content in the product oil is high,and the oil product fration is overall heavier.Mineral-enriched coal is rich in metal compounds with catalytic hydrogenation activity such as pyrite,but the content of organic matter is low.The gas and liquid yields in the coal/oil coprocessing reaction are both low,but the product oil quality is also good.The hydrogenation experiments of micro-component enriched coal samples and FCC oil slurry were carried out.It was found that,there is a significant synergy between coal and FCC oil slurry in the coal/oil co-processing reaction,which can significantly promote the conversion of coal to liquid products.Vitrinite-enriched coal and FCC co-refining process can promote the formation of aliphatic hydrocarbons;while inertite-enriched coal and FCC co-refining process can significantly promote the formation of aromatic hydrocarbons.Study on co-processing reaction characteristics of medium-low temperature coal tar from pyrolysis of raw coal and inertinite enriched coal with coal.Compared with the medium and low temperature coal tar obtained from the pyrolysis of raw coal,the medium and low temperature coal tar obtained from the pyrolysis of the inertinite group enriched coal has relatively lower content of aliphatic hydrocarbons and phenolic compounds,and higher content of aromatic hydrocarbons.In the co-processing process of coal and these two kinds of coal tars,the liquid yield and coal conversion were lower than those of FCC slurry co-processing,while the gas yield and coke yield were higher.In both coal tars,the content of polycyclic aromatic hydrocarbons is low,and the hydrogen transfer ability is weak,which leads to the competition between the free radicals obtained from coal cracking and the free radicals obtained from coal tar cracking in the reaction system for active hydrogen atoms in the reaction system.Co-processing reaction of coal tar mixed with FCC oil slurry with strong hydrogen transfer ability as solvent oil.It was found that,there is a strong synergy between the coal tar obtained from the pyrolysis of the inertinite-enriched coal and the FCC slurry.It shows that the aromatic compounds in coal tar and coal have high structural similarity and good mutual solubility.Coal tar strengthens the dissolution and dispersion of coal in the reaction system,and PAHs in the FCC slurry strengthen the hydrogen supply capacity of the reaction system,and the two synergistically promote the conversion of coal.This paper studies the separation of coal micro-components and the application of enriched coal with different micro-components in coal/oil co-processing,which provides basic experimental data and theoretical guidance for giving full play to the resource value of coal,realizing the coupling of coal quality classification and coal/oil co-processing technology,and innovating coal/oil co-processing technology.