关键词: 构造煤, 孔隙特征, 液氮吸附, 电镜扫描, 分形维数, 挥发分

Abstract: The pore structure characteristics of coal are closely related to gas absorption and transport. Due to damage caused by structural stress, the pore structure characteristics of tectonic coal tend to be complicated. Thus, investigating the development of tectonic coal pores is an important direction for improving the gas treatment level. In this paper, three groups of tectonic coal and a group of intact coal from the Dongyu Coal Mine in the southern part of the Xishan Coalfield were taken as the research object. Besides, the pore characteristics of tectonic coal and intact coal were jointly observed using a low-temperature liquid nitrogen adsorption method and scanning electron microscopy (SEM). As shown by research, the nitrogen adsorption amount of the three groups of tectonic coal was 2.04 times, 1.49 times, and 2.90 times that of intact coal. The pore volume of the three groups of tectonic coal was 2.08 times, 1.53 times and 2.96 times that of intact coal, respectively. The pore volume of the three groups of tectonic coal in micropore and small pores was more than 69.71%. The proportion of micropores in the pore specific surface area of the three groups of structural coal exceeded 79.04%. The micropores and micropores of intact coal provide 89.38% of the pore volume, and the pore specific surface area of micropores accounts for 93.97%. The pore structure of the three groups of tectonic coal was more complex than that of the intact coal and had larger fractal dimension (2.6985 to 2.7106). The fractal dimensions of three groups’ tectonic coal (10,000 times) were 1.962, 1.979, and 1.947, respectively, greater than that of intact coal. In comparison to intact coal, tectonic coal had more developed pore characteristics; the fractal dimension D1 was directly proportional to the total pore specific surface area and microporous surface area. The volatile content was directly proportional to the total pore surface area, microporous surface area, and small pore surface area within a certain range.