Laboratory Studies on Evaluation of Gasification Effect for Conversion of Coal Resources in Underground Coal Gasification (UCG) Reactors

Underground coal gasification (UCG) as a clean energy technology and efficient way for the conversion of the coal resources into energy in-situ has attracted wide public attention in recent years. Laboratory-scale experiments on coal blocks can provide significant insight into UCG process. The main goal of this study was evaluation of the gasification effect applying L-shape linking-hole and Coaxial-hole UCG models. Experimental results show the gas composition, AE activity and the temperature distribution inside the combustion reactors under similar operating parameters. Positive correlation was found between the temperature and cumulative AE events. The results shown that the gasification of L-shape linking-hole model obtained the average calorific value, as high as 11.3 MJ/m3, whereas in the Coaxial-hole model, the average calorific value of gas produced was only 5.79 MJ/m3under the experimental conditions. Even so, the results of conducted Coaxial-hole UCG experiment provide the original and sorely lacking data base for future new-style UCG research.