Semi‐industrial tests on enhanced underground coal gasification at Zhong‐Liang‐Shan coal mine

A new process of enhanced underground coal gasification (EUCG) has been demonstrated recently in successful semi-industrial tests at Zhong-Liang-Shan (ZLS) coal mine in China. The EUCG is featured using man-built pinnate channels and controlled moving injection points along coal-bed channel to produce syngas through underground coal gasification (UCG). To optimize the EUCG process, this field trial was performed with various operational manoeuvres, such as implementing controlled moving injection points, O-2-enriched operation and variation of operational pressure. The results showed that these operational techniques of the EUCG can ensure the gas flow comparatively controllable and hence improve UCG performance significantly, providing both a higher efficiency of heat and a higher quality of the production syngas.