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为分析低阶煤孔隙结构特征及其对瓦斯(甲烷)吸附特性的影响,采用高压容量吸附装置对3个低阶煤煤样和一个高阶煤煤样进行等温吸附试验和低温液氮吸附试验,并对比分析不同变质程度煤的吸附性能和孔隙结构。结果表明:低阶煤的吸附特性符合朗缪尔(Langmuir)方程;不同变质程度煤孔的结构存在明显差异,不同低阶煤的孔隙结构基本相近,在高压段均出现微小的滞后环,其孔形以两端开口的楔形孔为主,其对瓦斯的吸附主要集中于中孔和微孔中,中孔占比更大;煤体孔隙比表面积决定瓦斯吸附能力,中孔的比表面积与煤样的Langmuir体积线性相关,对吸附起决定性作用,而微孔的比表面积与Langmuir体积没有明显的正相关关系。
In order to analyze the characteristics of low-rank coal pore structure and its influence on gas (methane) adsorption characteristics, high-pressure capacity adsorption devices were used to conduct isothermal adsorption experiments and low-temperature liquid nitrogen adsorption experiments on three low-rank coal samples and one high- , And comparative analysis of different metamorphic coal adsorption properties and pore structure. The results show that the adsorption characteristics of low-rank coal conform to the Langmuir equation. There are obvious differences in the structure of coal pores with different metamorphic grades. The pore structures of different low-rank coal are basically similar with slight hysteresis loops appearing in the high pressure section. The pore shape is mainly wedge-shaped with two open ends. The adsorption of gas is mainly concentrated in the mesopores and micropores, and the mesopores occupy a larger proportion. The specific surface area of the pores determines the gas adsorption capacity, the specific surface area of the mesopores The Langmuir volume of coal samples linearly correlated, which played a decisive role in the adsorption. However, there was no obvious positive correlation between the specific surface area of micropores and Langmuir volume.