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

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.