Shaanxi Shanmei Binchang Mining Co., Ltd.
School of Safety Engineering, China University of Mining and Technology

煤体内部孔隙随着煤阶加深而逐步发育,在外界温度、压力等条件的影响下,瓦斯分子可通过吸附作用储存在煤体中。为了探明瓦斯分子在煤体纳米限域内的流动特性,使用傅里叶变换红外光谱、N2(77K)吸附等手段分析了样品内部官能团种类以及孔径分布。结果表明,煤层孔径以介孔居多,瓦斯分子在该限域条件下的流动会导致其在煤体中的分布不均;纳米尺度条件下,极性基团通过影响煤体表面势阱深浅达到影响瓦斯分子吸附能力的作用;煤体碳骨架发育致密过程中,孔径减小,气体分子运移通道受阻。煤体中微孔发育,墨水瓶形等封闭孔打开,形成圆柱形等连通状孔,增强了瓦斯吸附能力;瓦斯分子与煤体亲合力随着变质程度加深逐步增大,特征吸附能也随之增强;低阶煤样在低压条件下的解吸更为迅速。

Pores inside the coal body are developed gradually with the deepening of the coal rank, and the gas molecules canbe stored in the coal body by adsorption under the influence of external temperature, pressure and other conditions. To investigate the flow characteristics of gas molecules in the nano-confined domain of coal bodies, the kinds of internal functionalgroup and pore size distribution of the samples were analyzed by FTIR, N2 ( 77 K) adsorption and other means. The resultsshow that the pore size of the coal seam is predominantly mesoporous, the flow of gas molecules in the confined domain condition leads to its uneven distribution in the coal body, and under nanoscale conditions, polar groups have influences on theadsorption of gas molecules through effecting the potential well depth of the coal body surface. During the process of the carbon skeleton of the coal body gradually becoming dense, the pore size decreases, and the gas molecule transport channels areblocked. The intermediate and micro-pores of the coal body are developed, and closed pores such as ink bottle shape areopened to form connected pores such as cylindrical shape, thus enhancing the gas adsorption capacity. The affinity betweengas molecules and coal body gradually increases with the degree of metamorphism, and the characteristic adsorption energyalso increases. The desorption of low-order coal samples is more rapid under low pressure conditions.

国家自然科学基金面上项目(51974303);国家重点研发计划资助项目(2018YFC0807903)