Study On Preparation Of Super-clean Coal With Thermal Solvent Extraction

China is one of the largest countries in coal production and consumption in the world.With the development of economy,shortage of the resources of high rank coals is growing.Coal combustion has brought serious problems of pollution.Therefore,clean utilization of coal and high value-added utilization of coal are important directions for future development.Due to the super-clean coal,prepared with thermal solvent extraction,having many features such as ash-free,water-free,high thermal activity,good high flowability and others,it has been widely used in clean fuel preparation,coking,new materials fields gasification and liquefaction of coal.So more and more attentions have been paid and some researches were made on this project.In this thesis,a high pressure extraction reactor for thermal solvent extraction of coal was designed and manufactured,with which series experiments have been carried out.Washing oil from coking process was taken as solvent in the thermal solvent extraction.1/3 coking coal from xiaokang village and Baiyinhua lignite of Inner Mongolia were investigated on the properties of thermal extraction with the extraction reactor.The influence of operation conditions of thermal solvent extraction on the yield of extraction for 1/3 coking coal was studied.The yield of pyrolysis gas,the rate of deoxygenation,the change of pyrolysis gas components has been invetigated in the thermal solvent extraction of Mongolia Baiyinhua lignite.The results show that raising the initial pressure,prolonging residence time and increasing speed of agitator blade have little effection on improving the extraction rate.The coal extraction rate could be increased with the increase of extraction temperature,the decrease of particle size of coal.The optimum ratio of solvent volume to coal mass was 6:1.In the process of thermal solvent extraction for coal,with the breakage of the molecular chains of carbon and functional oxygen-containing groups,it will produce H2,O2,CO,CO2,CH4,C2H4,C2H6 and others.Initial pressure increased,the output of pyrolysis gas decreased.Gas yield and deoxygenation rate increase with the increasing of temperature,especially in 360?3 80 ?.The gas yield and deoxygenation rate decreased firstly and then increased,with the decreasing of ratio of solvent volume and coal mass,reaching the inflection point when the ratio of solvent volume and coal mass was 6:1.The experiments of thermal solvent extraction on 1/3 coking coal and Inner Mongolia Baiyinhua lignite in this thesis will provide data support and theoretical basis for the technology of thermal solvent extraction to prepare Super-clean coal.