Study on the effect of temperature on the adsorption and desorption characteristics of methane in coking coal with medium metamorphic degree

In order to explore the influence rule of temperature on the adsorption and desorption characteristics of methane in moderate degree coking coal, isothermal adsorption experiment and methane desorption experiment were used to analyze the changes of coal samples at different temperatures. Combined with Langmuir model, isosteric heat of adsorption, coal surface free energy and desorption capacity model, the obtained experimental data were analyzed. The results shows that with the increase of temperature, the adsorption capacity of methane and the adsorption constants a and b of Langmuir show a decreasing trend; the adsorption of coal is an exothermic process, and the isosteric heat of adsorption increases with the increase of methane adsorption; the temperature will lead to the change of the surface free energy of the coal, and the change of the surface free energy of the coal will decrease with the increase of temperature, so the adsorption capacity will decrease; the desorption curve has obvious Langmuir characteristics. The increase of temperature will promote the desorption of methane, and the desorption rate increases rapidly in the first 10 min.