基于红外成像技术的煤中甲烷分布特征研究

    Research on distribution characteristics of methane in coal based on infrared imaging technology

    • 摘要: 为了研究煤体在吸附过程中,甲烷的非均匀分布以及煤体温度的改变特征,通过红外热成像的方法和MATLAB程序,对不同变质程度的煤样进行观测分析。结果表明:在吸附过程中,不同煤阶的煤样截面具有不同范围的吸附明显区域,该区域温度变化大,且随着吸附压力的增大,该现象越显著;当煤样吸附达到平衡时,在任意吸附平衡压力下均存在某一温度变化临界值;在温度改变量大于该临界值的煤体截面区域范围,煤体中不同温度变化增量段的甲烷吸附量的分布比率高于煤单元数量分布比率,则定义该煤体区域为甲烷吸附聚积区;随着吸附压力的增大,煤样截面区域的温度变化范围变大,煤样吸附的非均匀性增强;随着温度变化量的增大,不同温度变化增量段的煤单元数量分布比率及其对应的甲烷吸附量分布比率呈现先增大后减小的趋势,服从正态分布。

       

      Abstract: In order to study the characteristics of the non-uniform distribution of methane gas and the non-uniform change of coal temperature during the adsorption process of coal, this paper uses infrared thermal imaging to observe the process of adsorption of methane gas on slice coal samples with different degrees of deterioration, and calculated and analyzed the captured infrared images through the MATLAB digital image processing program. The results show that during the adsorption process, the cross-sections of coal samples of different coal ranks have different ranges of obvious adsorption areas, which have greater temperature changes than other areas, and the phenomenon becomes more significant as the adsorption pressure increases. When the coal sample adsorption reaches equilibrium, there is a certain temperature change critical value under any adsorption equilibrium pressure. In the cross-sectional area of the coal body where the temperature change is greater than the critical value, the distribution ratio of the methane adsorption amount at different temperature change increment segments in the coal body is higher than the distribution ratio of the number of coal units, and then the coal body area is defined as methane adsorption accumulation area. With the increase of adsorption pressure, the temperature variation range of the three coal sample cross-sectional areas becomes larger, and the non-uniformity of coal sample adsorption increases; with the increase of temperature variation, the distribution ratio of the number of coal units and the corresponding distribution ratio of methane adsorption in the incremental segment of different temperature changes follow the trend of normal distribution.

       

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