构造煤与原生结构煤的孔隙结构及吸附性差异

Differences in Pore Structures and Absorptivity between Tectonically Deformed and Undeformed Coals

基于晋城和焦作煤样的吸附实验,对比分析了构造煤与原生结构煤的孔隙结构、吸附能力差异及其影响因素。结果表明,与原生结构煤相比,构造煤低温液氮吸附两阶段的拐点相对提前,中值孔径显著偏小,总孔容、微孔-中孔范围内各孔径段孔容以及相应的孔比表面积均要大几到十几倍。构造煤平均孔容具有微孔≈小孔>中孔的特点,原生结构煤却呈中孔>小孔≈微孔的规律,但两类煤体分段孔比表面积比例却不存在实质性差别。同时,构造煤吸附能力显著强于相同煤级的原生结构煤,原因在于构造煤的吸附孔孔容及相应的孔比表面积显著较高。此外,构造动力对煤孔隙结构乃至煤吸附性的改造可能涉及与煤大分子结构相关的微孔层次,有关现象和机理值得进一步深入探讨。

Based on the adsorption experiment of the coal samples from the Jincheng and Jiaozuo areas, the difference and geological controls of pore structure and adsorptivity between the tectonically deformed and undeformed coals were comparatively discussed. It was found that the turning point between two liquid nitrogen adsorption stages for the deformed samples move forward comparing to the undeformed samples, indicating the smaller median diameter and the larger volume and specific surface area of total, middle and micro-pores in the deformed samples. Tectonically deformed coals have larger micro- and small-pore volumes and smaller middle-pore volume, while undeformed coal show larger middle-pore volume and fewer small- and micro-pore volume, but the specific surface area at various pore size span does not exist substantial differences between two types of the coals. The absorptivity of the deformed coals is significantly stronger than that of undeformed coals with the same coal rank because the absorption pore volume and specific surface area of the deformed samples is significantly higher. In addition, it was suggested that the alteration of the tectonic dynamics to the pore structure and adsorptivity of coal may involve the micro-pore related to the macro-molecular structure of coal, which is worthy of further investigation.