Investigation of thermochemical process of coal particle packed bed reactions for the development of UCG

In this study, a packed bed reactor was developed to investigate the gasification process of coal particles. The effects of coal particle size and heater temperature of reactor were examined to identify the thermochemical processes through the packed bed. Three different coal samples with varying size, named as A, B, and C, are used, and the experimental results show that the packed bed with smaller coal size has higher temperature, reaching 624 °C, 582 °C, and 569 °C for coal A, B, and C, respectively. In the case of CO formation, the smaller particle size has greater products in the unit of mole fraction over the area of generation. However, the variation in the porosity of the packed bed due to different coal particle sizes affects the reactions through the oxygen access. Consequently, the CO formation is least from the coal packed bed formed by the smallest particle size A. A second test with the temperature variations shows that the higher heater temperature promotes the chemical reactions, resulting in the increased gas products. The findings indicate the important role of coal seam porosity in underground coal gasification application, as well as temperature to promote the syngas productions.