Supercritical Gas Extraction of South African Coals

Abstract

Abstract The supercritical gas extraction of South African coals was carried out using semi-continuous reactors. The conversion (to liquid and gaseous products) increases as the volatile matter yield or the H/C atomic ratio of the coal increases and as the critical temperature or the Hildebrand solubility parameter of the solvent increases. The effect of pressure and temperature on the conversion is discussed. The chemical nature of the oils (hexane soluble product) from supercritical gas extraction at 350°C and 450°C is also reported.