Up-grading of Solvolytic Coal Liquids into a Feedstock for the Needle-Cokes

Carbonization properties of the solvolytic coal liquid (SCL) which was produced thermally from the mixture of a coking coal and a petroleum asphalt were studied to find its utilization procedure as a feedstock for needle-cokes. The cokes obtained singly from SCL showed a heterogeneous appearance of isotropic and fine mosaic texture. Although its cocarbonization with Ashland Petroleum pitch A 240 and its hydrogenated one HA 240 allowed uniform development of mosaic texture, the flow texture characteristic to the needle coke still failed to demelop. BH-SCL, hydrogenated SCL with lithium-ethylenediamine, produced cokes of elongated mosaic texture. In contrast, CH-SCL, hydrotreated SCL with a Co-Mo catalyst under hydrogen pressure, could develop the excellent flow texture, although the coke yield was considerably decreased. High coke yields were achived by the solvent fractionation with hexane or benzene-ethanol mixture, maintaining the excellent flow texture development. Comparing the structural indices of SCL, BH-SCL, and CH-SCL, which were modifying during the up-grading processes, structural characteristics required for the flow texture development were discussed in the carbonization scheme according to the mesophase mechanism.