Liquefaction behaviour of Kolubara soft brown coal

The behaviour of Kolubara soft brown coal during direct liquefaction by catalytic hydrogenation was studied and was compared with the Banovići brown coal investigated previously. A sample of washed and dried coal was ground dry, or was ground in the presence of different liquids. Addition of water during grinding resulted in a somewhat coarser granular composition, while n-heptane did not have a noticeable effect. High reactivity of the soft brown coal, which initially was indicated by thermal analysis, was confirmed by high yields of liquid products, particularly of oils soluble in n-heptane. The solid liquefaction residues did not contain pyrolytic carbon and cenospheres, and contained a low proportion of humoplasts indicating the high liquefaction efficiency of the coal in spite of its high content of xylite.