Lin Huaying, Tian Shixiang, Jiao Anjun, Cao Zuoyong, Song Kai, Zou Yihuai
College of Mining Engineering, Guizhou University, Guiyang 550025, Guizhou, China.
The National Joint Engineering Laboratory for the Utilization of Dominant Mineral Resources in Karst Mountain Area, Guizhou University, Guiyang 550025, Guizhou, China.
ACS Omega. 2022 Jul 25;7(31):27300-27311. doi: 10.1021/acsomega.2c02222. eCollection 2022 Aug 9.
Understanding the pore heterogeneity of tectonic coal and primary-structure coal is of great significance for predicting and preventing tectonic coal. This study adopts the low-temperature nitrogen adsorption method, mercury injection experiment, and other methods, combined with fractal theory, to quantitatively analyze the pore distribution of coal samples inside and outside the outburst cavities of the Sanjia coal mine. The experiments have shown that the contents of aliphatic functional groups and hydrogen in tectonic coal are higher than those of aromatic structural functional groups. Raw coal has more straight chains than side chains, whereas aliphatic hydrocarbon mostly has short chains, and the branching degree is high. Soft and primary-structure coals have similar elemental content and tectonic effects endow the coal with better connectivity. The pores are filled with particles and flakes, and the surfaces of tectonic coal have more pores and fissures on them. According to the experimental curve, the pores are divided into five types. The pore size of primary-structure coal is mainly type II pores, and the pore size distribution of tectonic coal is relatively wide, with the majority being class I and class II pores. The specific surface area of tectonic coal is 60.7% more than that of primary-structure coal. The box fractal dimension of coal decreases with the increase in scanning electron microscopy (SEM) magnification. The minimum fractal dimension of tectonic coal is 2.49, which is 7.8% lower than the peak of 2.70. It can be seen from the fractal dimension that the fractal dimensions of pore types II, III, and IV are rougher.
认识构造煤与原生结构煤的孔隙非均质性对构造煤的预测与防治具有重要意义。本研究采用低温氮吸附法、压汞实验等方法，结合分形理论，对三家煤矿突出孔洞内外煤样的孔隙分布进行定量分析。实验表明，构造煤中脂肪族官能团和氢的含量高于芳香结构官能团。原煤的直链比侧链多，而脂肪烃大多为短链，支化度高。软煤与原生结构煤具有相似的元素含量，构造作用赋予煤更好的连通性。孔隙中填充有颗粒和薄片，构造煤表面有更多的孔隙和裂隙。根据实验曲线，将孔隙分为五类。原生结构煤的孔径主要为Ⅱ类孔，构造煤的孔径分布较宽，以Ⅰ类和Ⅱ类孔为主。构造煤的比表面积比原生结构煤大60.7%。煤的盒维数随扫描电子显微镜（SEM）放大倍数的增加而减小。构造煤的最小分形维数为2.49，比峰值2.70低7.8%。从分形维数可以看出，Ⅱ、Ⅲ、Ⅳ类孔隙的分形维数更粗糙。
