A Study of Thermal Dissolution of Coal and Utilization of its Soluble Fraction

The thermal dissolution (TD) of coal provides a new way for the high efficient and clean utilization of coal. The development of TD technology of coal and the utilizations of thermal dissolution soluble fraction (TDSF)wereintroduced.Theeffectsofsolvent,temperature,additiveandpretreatmentofcoalontheTDperformances of coal were reviewed. The catalytic TD of coal and its catalyst selection were also discussed. In addition, according to the characteristics of high thermoplasticity, strong caking property, low ash content and high reactivity of TDSF, its utilizations in the coke-making of blending coal, the preparation of coal-based fuel and coal-based nano carbon materials were also discussed. It has suggested that suitable solvent, TD temperature and additive can break non-covalent and weak covalent bonds, relax macromolecular network structure of coal, thus promoting the TD of coal, and improving the yield of TDSF. Polar solvent, especially for organic compounds containing nitrogen such as indole, can relax the macromolecular network structure of coal by induction. The non-covalent and weak covalent bonds in coal can be broken in different degrees at appropriate TD temperature. Additives can also disassociate the structure of coal. Acid and base treatment can remove partially mineral in coal, thus destroying some ionic bonds in coal. Hydrothermal pretreatment can break some hydrogen bonds in the coal.