Study on Pyrolysis Characteristics and Kinetics of Bituminous Coal by Thermogravimetric Method

During the underground coal gasification process, due to the particularity of the gasification channel, a large amount of coal pyrolysis will occur in the coal seam. By studying the characteristics of pyrolysis and gasification of bituminous coal, using the gaseous material containing C element in pyrolysis atmosphere as the way to calculate the conversion rate of lignite. In this paper, thermogravimetric simulation test bench is used to study the pyrolysis characteristics and kinetics of bituminous coal. The weight loss rate under different pyrolysis conditions is analyzed and studied. The following main conclusions are obtained: in the process of bituminous coal pyrolysis, rapid heat transfer to the interior is an important means to improve the pyrolysis efficiency of bituminous coal. The residence time of pyrolysis process is increased, so that the temperature is fully transferred in the coal sample. Therefore, more pyrolysis gas and liquid products can be obtained. The faster the heating rate, the higher the critical temperature of the bituminous coal and the lower the conversion rate. This is because the temperature transfer is lagging and the heating rate is fast, which results in the bituminous coal below the set temperature. The temperature of bituminous coal is shifted back. The formation of CH(4)in bituminous coal mainly occurs in the depolymerizing stage. The formation of H(2)mainly occurs in the condensation polymerization stage, and its formation requires higher temperatures.