Meng Junqing, Li Shichao, Niu Jiaxing
School of Emergency Management and Safety Engineering, State Key Laboratory of Coal Resources and Safe Mining, and Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources, China University of Mining and Technology, Beijing 100083, China.
ACS Omega. 2019 Nov 26;4(24):20762-20772. doi: 10.1021/acsomega.9b03165. eCollection 2019 Dec 10.
The ability of coal to adsorb methane depends on the coal microstructure; however, the research on its exploration is still underway. In this paper, a new method was adopted to investigate the evolution characteristics of the crystallite structure of eight different rank coals and its influence on the methane adsorption capacity. The crystallite lattice parameters, including , , , , and , were determined by curve fitting analysis of X-ray diffraction (XRD) spectra. The methane adsorption experiments were carried out through a static capacity method, and the methane adsorption parameters ( , ) were measured. Correlations were established for the crystallite lattice parameters and the methane adsorption parameters. From the results obtained, there is a good negative linear relationship between and and a good exponential relationship between and , indicating that the increasing can weaken the methane adsorption capacity. displays an exponential increase with increasing and , while presents a linear decrease, but reverse variations are emerged in the process of change for both, and the methane adsorption capacity is weaken temporarily. presents a lognormal distribution with increasing , and the minimum value appears at = 1.85-1.9 nm. and both obey lognormal distribution with increasing / , but their trends are completely opposite, and the methane adsorption capacity is the strongest at / = 0.85-0.9. As increases, and present an overall exponential increase and an overall exponential decrease, respectively, but reverse changes also emerge. The methane adsorption is related to the crystallite structure characteristics of coal. Finally, the influence mechanism of the crystallite structure evolution on the methane adsorption capacity was analyzed, which has great significance for prevention of gas disasters in underground coal mines.
煤吸附甲烷的能力取决于煤的微观结构；然而，对其的探索研究仍在进行中。本文采用一种新方法来研究八种不同煤阶煤微晶结构的演化特征及其对甲烷吸附能力的影响。通过对X射线衍射（XRD）光谱进行曲线拟合分析，确定了微晶晶格参数，包括 、 、 、 和 。通过静态容量法进行甲烷吸附实验，并测量甲烷吸附参数（ 、 ）。建立了微晶晶格参数与甲烷吸附参数之间的相关性。从所得结果来看， 与 之间存在良好的负线性关系， 与 之间存在良好的指数关系，这表明 的增加会削弱甲烷吸附能力。 随 和 的增加呈指数增长，而 呈线性下降，但两者在变化过程中均出现反向变化，且甲烷吸附能力暂时减弱。 随 的增加呈对数正态分布，最小值出现在 = 1.85 - 1.9 nm处。 和 随 / 的增加均服从对数正态分布，但趋势完全相反，且在 / = 0.85 - 0.9时甲烷吸附能力最强。随着 的增加， 和 分别呈现总体指数增长和总体指数下降，但也出现反向变化。甲烷吸附与煤的微晶结构特征有关。最后，分析了微晶结构演化对甲烷吸附能力的影响机制这对煤矿井下瓦斯灾害防治具有重要意义。
