Meikuang Anquan (Jul 2022)
Influence of temperature on methane adsorption characteristics of soft and hard anthracite based on molecular simulation method
Abstract
As coal mining extends to the deep, the influence of stratum temperature on coal gas adsorption performance cannot be ignored. In this paper, soft and hard anthracite are taken as the research object, and the macromolecular structure model of coal is established based on molecular simulation technology. The methane adsorption of four groups of coal samples at 293.15-333.15 K is simulated. Based on this, the influence difference of temperature on the adsorption parameters of anthracite is analyzed, and the adsorption heat of four groups of coal samples is calculated. The calculation equation of coal seam gas content under temperature effect is further analyzed. The results show that with the increase of temperature, the Langmuir volume of soft and hard anthracite decreases continuously while the Langmuir pressure increases. The Langmuir volume of the four groups of coal samples changes most sensitively at 30-40 ℃, and the Langmuir pressure of soft coal is more significantly affected by temperature. The adsorption heat of the four groups of coal samples is about 15 kJ/mol. It is found that it is feasible to study the methane adsorption characteristics of soft and hard anthracite by using the super crystal cell structure model of coal macromolecules, and the adsorption heat of soft coal is higher than that of hard coal. Both the temperature influence coefficient and temperature of soft and hard anthracite can be characterized by exponential equation, in which the relationship between the temperature influence degree coefficient n and methane pressure satisfies the form of power function. Meanwhile, if the temperature influence coefficient of soft medium is smaller than that of hard coal, the influence of temperature on the gas adsorption capacity of soft coal is more prominent.
Keywords
