Residual coal distribution in China and adaptability evaluation of its resource conditions to underground coal gasification

摘要

This paper researched the distribution and the characteristics of residual coal resources for their adaptability into underground coal gasification (UCG) technology to promote a potential green technology for the development of residual coal resources in China. The results reflected that the average recovery rate of resources for coal mines was only 37.67% in China, and the residual coal reserves reached 148.53 gigatons (Gt), of which 52.51% occurred in North China. Furthermore, these resources are mainly distributed in the buried depth shallower than 800 m, accounting for 87.15%. And residual coal types were primarily bituminite with a percentage of 72.89%. We established a multi-level model with membership functions that included an analytic hierarchy and a fuzzy comprehensive evaluation with variable weight theory. As a result, a varying weight fuzzy hierarchical evaluation model for the resource conditions feasibility of residual coal with UCG technology was established. Finally, the model was applied to the resource condition feasibility evaluation of UCG industrial tests at Zhongliangshan, Huating, and Shanjiaoshu Mines. The industrial tests showed that the evaluation model constructed in this paper could comprehensively, objectively, and intuitively reflect the adaptability of residual coal resources to UCG technology, providing a scientific reference for UCG project decision-making.