Method of liquefying brown coal

Abstract

A method for the liquefaction of brown coal which comprises effecting primary hydrogenation at a temperature and pressure sufficient to promote the efficient hydrogenation of a slurry prepared by adding an iron-based catalyst and a slurrying solvent to brown coal; distilling all or a portion of the primary hydrogenation product, whereby a naphtha fraction, a middle distillate oil fraction, a heavy distillate oil fraction and a distillation residue are produced; recycling a portion of said middle distillate oil, said heavy distillate oil fraction and said distillation residue to said primary hydrogenation step as the slurrying solvent; removing ash from the remaining portion of the distillation residue, thereby separating the same into an insoluble fraction containing ash, insoluble organic matter or a mixture thereof, and a soluble fraction as a solution in said solvent; and feeding said soluble fraction and said middle and heavy distillate fractions, to a fixed-bed column reactor packed with a molybdenum-based catalyst for secondary hydrogenation at a temperature and pressure sufficient to promote the efficient hydrogenation thereof; and separating the naphtha fraction from the secondary hydrogenation product and recycling all or a portion of the remainder to said primary hydrogenation step as the slurrying solvent therefor.