Sub- and supercritical water extraction of goynuk oil shale

Goynuk oil shale was extracted with water at sub- and supercritical conditions. The pressure was varied from 0.1 to 32 MPa. The highest extraction temperature was 419degreesC. Under these conditions, the conversion degree, extract, and gas yields increase with temperature since the thermal cracking of the crosslinked polymerized coal structure leads to the formation of extractable products. Above the critical temperature of water the conversion degree and extract yield decreased as a result of repolymerization of extracted products. Spent shale amount decreased with increasing temperature. The obtained extracts at different temperatures were separated into subfractions. It was attempted to explain the effect of experimental conditions on yields and the amount of subfractions as well.