2001 Volume 80 Issue 4 Pages 274-277
A preliminary study on supercritical methanol extraction of a brown coal, Loy Yang, was conducted. The experiments were done at 400°C with varying the extraction time or the coal/solvent ratio. When the extraction time was extended from 60min to 300min, the extraction yield remained constant but the liquid yield was reduced from 70% to 60%. This suggested that the extract further decomposed into gaseous components during the extended extraction. The increase in the coal/solvent ratio led to the decreases in the extraction and liquid yields, and the decrease in the liquid yield was more remarkable than that in the extraction yield . The pressure in the autoclave increased with the increasing coal/solvent ratio. These observations indicated that the increase in the coal/solvent ratio led to pyrolysis of coal as a dominant chemical process rather than the degrading reaction of coal polymer by the action of supercritical methanol as a reagent. A GC-MS study on a liquid extract revealed that the major chemicals were methyl-substituted phenols and a phenol-methyl ether.