Application Of Catalyst In Preparation Of Super-Clean Coal By 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.The super-clean coal,prepared with thermal solvent extraction,is an effective way to realize coal cleaning and high added value utilization.However,with the increase of coal rank,the structure of large molecular aliphatic hydrocarbon chain and aromatic ring increases,and it is difficult to break down the bond in the process of thermal extraction,which results in the decrease of extraction rate of super-clean coal.In this thesis,the application of catalyst in thermal solvent extraction of high rank coal was studied by self-developed technology.Using typical Lewis-acid metal salt ZnCl₂ as catalyst,catalytic performance of thermal solvent extraction were investigated on three kinds of lean coal?Shanxi Sima lean coal,Inner Mongolia Wuhai lean coal,Xingtai Sanji village lean coal?under the experimental conditions.The experimental results showed that it has catalytic activity for different coal species.The study of different series of Lewis-acid metal salt showed that ZnSO₄ has the best catalytic effect,the extraction rate of super-clean coal was 46.1%,and the optimal quantity of catalyst was about 5%.ZnSO₄ can effectively break the macromolecular organic structure of coal to produce free radical solution extraction agent,and separate inorganic mineral components in the extraction residue.Recovered ZnSO₄ also have good catalytic performance,and can be recycled.Using ZnO?MgO and Fe₂O₃ as catalyst,catalytic performance of thermal solvent extraction were investigated under the experimental conditions.It showed that ZnO has the best catalytic effect,the extraction rate of super-clean coal was 46.6%,Using ZnO as catalyst,the effects of different preparation methods and optimized preparation conditions on the catalytic performance were studied.The results showed that,under the optimal conditions,ZnO prepared by direct precipitation method was obtained for high purity six party spherical crystals.The extraction rate of super-clean coal was 49.7%.ZnO can promote the C-C bond and C-H bond breaking in aliphatic hydrocarbon chain and aromatic ring and improve the extraction rate of super-clean coal.Thermogravimetric analysis showed that super clean coal which prepared by Sima lean coal has the characteristics of low softening temperature,wide softening melting temperature range,good fluidity and finethermalactivity.Gelatineous layer of the mix coal which coordinate 20%super clean coal with 80%Sima lean coal was tested.It showed that the samples have good coking value and are in a state of complete fusion.