Structural Characteristics and Direct Liquefaction Performance of Macerals in Yili Coal from Xinjiang.

Effectively separating and utilizing macerals based on their properties is crucial for the efficient and high-value utilization of coal. This study enhances the traditional screening method by employing primary and stepwise crushing techniques to separate Yili coal (YLC) into inertinite-rich (YLI) and vitrinite-rich (YLV) concentrates. The structural characteristics and direct coal liquefaction (DCL) performance of YLC, YLV and YLI are subsequently studied. The results indicate that YLV exhibits the highest yield of oil, asphaltene and gas, a finding closely linked to its elevated content of highly active functional groups and its long aliphatic and bridge chains. Furthermore, the liquefaction oil from YLV contains the highest content of alkanes and phenols, which is attributed to its high content of aliphatic hydrocarbons and phenolic hydroxyl groups. In contrast, YLI exhibits the lowest product yield relative to YLC and YLV, with the highest contents of aromatics, esters, and ketones in its oil, due to its high contents of aromatic and carbonyl carbon. The separation, structural characteristics and DCL studies of macerals from Yili coal offer valuable insights for the efficient separation and utilization of macerals.