Recent Advances in Direct Coal Liquefaction

The growing demand for petroleum, accompanied by the declining petroleum reserves and the concerns over energy security, has intensified the interest in direct coal liquefaction (DCL), particularly in countries such as China which is rich in coal resources, but short of petroleum. In addition to a general introduction on the mechanisms and processes of DCL, this paper overviews some recent advances in DCL technology with respect to the influencing factors for DCL reactions (temperature, solvent, pressure, atmospheres, etc.), the effects of coal pre-treatments for DCL (swelling, thermal treatment, hydrothermal treatment, etc.), as well as recent development in multi-staged DCL processes, DCL catalysts and co-liquefaction of coal with biomass.