温度对中高阶烟煤甲烷吸附—常压/带压解吸过程中煤体变形影响实验

为探究不同温度条件下中高阶烟煤在吸附、常压/带压解吸甲烷过程中的变形特征，以取自山西省的5件中高阶烟煤为研究对象，采用自行设计的吸附/解吸变形测量仪进行了甲烷吸附—常压解吸（出口压力为大气压）及吸附—带压解吸（出口压力逐次降低）过程模拟，动态监测了不同温度条件下甲烷吸附—解吸过程中的煤体变形特征。结果表明：甲烷吸附—解吸过程中产生的煤体变形的增量随时间的增长逐渐减小，由于煤样的非均质性使得不同方向的煤体变形量存在差别，垂直层理方向变形量大于平行层理方向，变形量与吸附/解吸量呈现正相关关系。部分甲烷被煤样吸附后在大气压条件下无法重新解吸，使得煤样在吸附—解吸循环后存在一定残余变形。煤样吸附量、吸附膨胀变形量及残余变形量随温度升高整体上呈现为减小的趋势，但解吸率与温度呈现为正相关趋势，且常压解吸过程解吸率随温度变化更为明显，说明了温度升高使得煤样吸附能力减小，煤体变形量随之减小，另一方面温度升高促进了甲烷解吸并抑制了甲烷吸附，使得煤样解吸率提高，残余变形量随之减小。

Characteristics of medium-high rank bituminous coal deformation during methane adsorption- desorption with atmospheric pressure/with successively decreasing outlet pressure at different temperatures

To explore the deformation characteristics of medium-high rank bituminous coal during the process of methane adsorption-desorption at different temperatures， five coal samples from Shanxi Province were selected for this study. The processes of adsorption- under atmospheric pressure desorption and adsorption-pressure desorption（successive reduction of outlet pressure）of methane were simulated by custom-designed instruments. The deformation characteristics of this suite of coals during adsorption and desorption at different temperatures were dynamically monitored. The results show that the amount of coal deformation in the process of adsorption and desorption decreases gradually with the increase of time. Due to the heterogeneity of coal samples，the deformation in different directions is slightly different. The deformation perpendicular to the bedding direction is greater than that of parallel to the bedding direction. A positive correlation was found between the strain and the volume of adsorption/desorption. After methane is adsorbed by coal samples， not all adsorbed methane can be desorbed again under atmospheric pressure， resulting in some residual deformation of coal after an adsorption desorption cycle. The adsorption volume， swelling induced by adsorption and residual deformation of coal samples all show a decreasing trend with increasing temperature. However， the desorption rate and temperature show a positive correlation trend， and the desorption rate changes more obviously with the temperature in the atmospheric desorption process. It indicates that the adsorption capacity of coal decreases with the increase of temperature， which in turn results in the decrease of coal deformation. On the other hand， the increase of temperature promoted methane desorption and inhibited methane adsorption， resulting in the increase of coal desorption rate and the decrease of residual deformation.