The Generate Mechanism Research Of Coal-based Liquid Fuel In The Catalytic Thermal Dissolutions

The thermal dissolution（TD）technology of coal has been considered as an effective way to produce coal-based aviation alternative fuel.However,the chemical composition of the obtained liquid fuel is relatively complex,which has become a bottleneck problem restricting its subsequent utilization.This paper studies the formation mechanism of coal-based liquid fuel under catalytic TD,realizes the directional formation of specific components,which provides theoretical basis for the research and development of coal-based aviation alternative fuel preparation technology.In this paper,methanol was used as solvent and Mo-Ni,ZSM-5 and metal supported catalyst were used to catalyze the TD of Indonesian lignite（YN）at different TD temperatures.The solution portion、thermal residual coal and gaseous puducts were analyzed by GC-MS,FTIR and GC.The catalytic thermal dissolution behavior of lignite was studied,compares and analyzes the influence of catalyst on the directional formation of specific components of liquid fuel,and explores the mechanism of catalytic TD of lignite.The results show that the TD rate is the highest under Mo-Ni catalysis.The esters in the solution portion decrease sharply with the increase of the TD temperature,and the aromatic hydrocarbons and phenols increase accordingly.The increase of ketones in the high temperature section under the catalysis of molecular sieve catalyst shows the formation rule of solution portion in different catalytic TD.The component of solution portion in metal supported catalyst are related to the amount of metal loaded.With the increase of TD temperature,H₂,CO₂and CO increase sharply under Mo-Ni catalysis.The low-carbon hydrocarbon gases CH₄and C₂H₆increased significantly under molecular sieve catalysis,while H₂increased significantly under metal supported catalysis,suggesting that different catalysts have different catalytic effects in the process of TD of coal.Under the catalytic TD of coal,the long linear alkanoic acid methyl ester dissolved from macromolecular structure of lignite undergoes catalytic cracking to form low-carbon alkanes.Through different catalytic paths such as hydrogen transfer and direct dehydrogenation,aromatization reactions take place to form aromatic rings,on which methylation,nucleophilic substitution and polymerization can take place to form phenol,monocyclic and polycyclic aromatic hydrocarbons.