热效应对焦煤甲烷解吸迟滞特征的影响研究*

为揭示煤中甲烷气体的储运机制，选取井下煤样研究不同温度条件下甲烷气体的等温吸附解吸实验。基于Langmuir模型、等量吸附热计算模型和解吸迟滞系数对实验数据进行分析，研究煤中甲烷气体解吸迟滞现象的热力学特征。结果表明:随温度升高，Langmuir模型得到的吸附常数均呈下降趋势；甲烷解吸迟滞现象明显，迟滞程度随温度升高缓慢下降；受解吸迟滞效应影响，相邻温度区间内吸附曲线的等量吸附热较为相近，不同温度区间内解吸曲线的等量吸附热高于吸附曲线，差异显著；解吸迟滞现象影响煤层甲烷含量预测的准确性，并且解吸曲线的热力学特征规律性较差。

Study on influence of thermal effect on methane desorption hysteresis characteristics of coking coal

In order to reveal the storage and transportation mechanism of methane in the coal,the underground coal samples were selected to carry out the isothermal adsorption and desorption experiments of methane under different temperatures.The experimental data were analyzed by the Langmuir model,the calculation model of isosteric adsorption heat and the desorption hysteresis coefficient,then the thermodynamic characteristics of methane desorption hysteresis in the coal was studied.The results showed that all the adsorption constants obtained by the Langmuir model decreased with the increase of temperature.The desorption hysteresis of methane was obvious,and the degree of hysteresis decreased slowly with the increase of temperature.Due to the influence of desorption hysteresis effect,the isosteric adsorption heat of the adsorption curves in the adjacent temperature ranges were similar,and the isosteric adsorption heat of desorption curves were higher than those of adsorption curves in different temperature ranges,with the significant difference.The desorption hysteresis would affect the accuracy of methane content prediction in the coal seal,and the regularity of thermodynamic characteristics for the desorption curves was poor.