Methods of Coal Liquefaction

The methods of production of liquid fuels and chemical products from coal are considered. The most universal method for producing liquid products from coal is direct hydrogenation, i.e., the production of molecular hydrogen under pressure at elevated temperature using a liquid product (paste) and catalysts. During hydrogenation about 90% of coal is converted into gas and liquid products. In the process of coal hydrogenation, stabilization of coal radicals occurs due to H-donor hydrogen, the activation of which can be passed through the catalyst. One of the most important factors in the coal liquefaction process is the presence of hydroaromatic and hydrogen-donor substances of coal origin in the solvents. The hydrogen donor was found to be 1,2,3,10 β-tetrahydrofluoranthene, 4,5-dihydropyrene, hexahydropyrenes and 9,10-dihydrophenentrenes. A good solvent-hydrogen donor substance tetralene was found, the degree of transformation of OMP was 90% in 15 min, and tetrahydroquinoline was a low-metamorphosed carbon (degree of transformation of OMP less than 80%). The degree of conversion of 100% was given by a mixture of oil ash with tetrahydroquinoline. It is recommended to use polymetallic ore processing sludge and metal sulfides as catalytic additives. The use of iron sulfates or sulfites as catalysts, accelerating the cleavage of C-C bonds in coal, and the use of AlCl3, SbCl3, ZnCl2, BF3, SnCl2 compounds as catalysts among various solvents showed that the coal hydrogenation process can be carried out under mild conditions (initial pressure 0,1 MPa, temperature at least 200°C).