Effective utilization of Mongolian coal by upgrading in a solvent

Liquid-phase upgrading of Mongolian low-rank coals, which are rich in oxygen, having low heating value, was investigated using 200 ml autoclave at 380–440 °C in the presence of t-decalin and coal tar as solvent under 2 MPa of initial nitrogen atmosphere. The upgrading of Baganuur-2A and Shivee ovoo coal at 440 °C in t-decalin gave 9.7–10.2 wt.% of gas, 3.7–4.5 wt.% of oil, 4.4–8.4 wt.% of water and 77–82 wt.% of upgraded solid product. The heating value of the upgraded solid product from Baganuur-2A coal increased to 32.9 MJ/kg as compared to the heating value of raw coal, which was 26.3 MJ/kg, and for the Shivee ovoo coal, it was reached from 21.2 to 28.8 MJ/kg. The upgrading process has influenced significantly the enhancement of the aromaticity and the spontaneous ignition temperature of the raw coal. The distribution of aromatic stacking layers (N) is slightly higher for the upgraded solid products treated at 440 °C than raw coal. The Baganuur-2A, Shivee ovoo coals and these upgraded solid products were mixed with Goonyella bituminous coal and tested on gieseler plastmeter to characterise thermoplastic behaviour.