Challenges faced by underground coal gasification and technical countermeasures

China’s energy structure is characterized by “rich coal and insufficient gas”. Underground coal gasification is to obtain gas resources through controlled combustion of coal resources under in-situ conditions. It has two advantages: the clean utilization of coal and the guarantee of low-carbon energy resources. It will become an important field in the development of clean and efficient modern energy system in China. This paper systematically summarized the development history of underground coal gasification at home and abroad. Based on the analysis of many examples, it is pointed out that most of underground coal gasification tests that have been carried out in the world are carried out in shallow coal seams, and the safety, environmental protection and economy are the challenges faced by the large-scale development of underground coal gasification.In terms of coal resources,the underground gasification of deep coal has more advantages. The analysis shows that the smooth and effective implementation of underground coal gasification in China will face several key problems: the evaluation system for the selection of underground coal gasification has not been established, the research on the construction technology of gasifier matching with geological conditions has not been carried out, the research on the relationship between gasification agents and gasification products of different types of coal resources is not clear, and the targeted policy support has not been formed.In order to smoothly promote the pilot test and industrial test, it is urgent to combine the geological conditions of coal resources to establish an evaluation technology for underground coal gasification selection in China; systematically carry out the research on the adaptability of gasification technology for different types of coal resources, develop the applicable gasifier construction technology. The appropriate gasification process is selected to control the proportion of economic substances in the gasification product, and the continuous adjustment and optimization are carried out to form a targeted gasification product control technology. While realizing the safe, efficient and clean development of coal resources, it also guarantees energy security, improves energy structure and creates economic benefits.