Liquefaction reactivity and ¹³C-NMR of coals rich in barkinite and semi-fusinite

Coals rich in barkinite and semi-fusinite were selected to study their liquefaction behavior as well as their chemical structure, and to seek correlations between the yield of liquefaction products and chemical structural parameters. The liquefaction tests were done in tubing-bomb reactors in a pre-heated sand bath. The samples were characterized by ultimate analysis, proximate analysis, petrographic analysis and ¹³C -NMR. The results show that barkinite-rich samples contain higher hydrogen and volatile matter contents, and have higher H/C atomic ratios. The chemical structures of the samples used are rich in aromatic carbon. The aromaticity of WEST coal was the highest. The content of methylene carbons of LP, CG and DHB coals is higher than methyl carbon, and is also higher than in the other three coal samples. The LP, CG and DHB coals have higher liquefaction conversions and higher yields of oil. Definite correlations between the yield of oil and the content of methylene carbons and between liquefaction conversion and aromaticity have been observed, which indicates the yield of liquefaction products can be predicted on the basis of solid state ¹³C-NMR spectral data of coal.