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

The coal-based aviation jet alternative fuels prepared from coal can provide an effective way to solve the supply problem of jet fuel and improve the traditional fuel properties.Further research on the formation mechanism of coal-based solution products is of great significance to the directional preparation and application of coal-based thermal dissolution liquid fuels.In this study,the thermal dissolutions?TD?of an Indonesian lignite are carried out under different temperature?100?,150?,210?,250?,280?,300?,310??in different solvents?methanol,cyclohexane,Tetralin and methanol+cyclohexane mixed solvent?.During TD,the changes of TD rate,gaseous puducts and chemical structures of solution puducts and thermal residual coal are investigated to further analyze the thermal dissolution behaviors.The effects of thermal temperature and thermal solvent on the TD behavior of lignite are comparatively analyzed to study formation mechanism of coal-based liquid products during TD.The experimental results showes that the transesterification between methanol and carbon alkyl esters resulted in the rapid increase of ester compounds at 210?,and thereafter the fracture of some weak covalent bonds?oxygen-containing bridges?further led to a large number of phenols when thermal temperature increased up to 280?.Methyl mercuric compounds formed by methanol alkylati on reaction,accompanying the release of CH₄,H₂,C₂H₆ and other gaseous products.The thermal dissolution rate in cyclohexane and tetralin increased gradually with the increase of thermal temperature,CO₂ and CO were mainly gaseous products,which is due to the interaction between the nonpolar solvent and the coal molecules.The alkanes and aromatic compounds are mainly solutes puducts from TD in cyclohexane and Tetralin,indicated the TD process is mainly dominated by physical thermal solution.The chemical structure of Tetralin and its high boiling point caused the higher aromatic content in solubles puducts from tetralin and the higher TD rate.The higher TD rate from a mixed solvent of methanol and cyclohexane suggested that the interaction between methanol and cyclohexane could improve the TD rate of lignite.