Influence of Normal Coal and Deformed Coal on Isosteric Enthalpy of Desorption

According to the temperature-pressure-adsorption equation, the series of isotherm adsorption data of both normal coal and deformed coal with high-rank and middle-rank have been effectively converted. The isosteric enthalpy of adsorption of these coals are calculated. The adsorption isotherms of these coals are the system exothermic to the environment, and the more exothermic the system is, the more stable the system is. While the desorption is that the system endothermic from the environment, and the less endothermic the system is, the more stable the system is. When the adsorption capacity is 25.0 cm3/g, the exothermic heat of the unit isosteric enthalpy of adsorption is 1.108 kJ·mol−1·cm−3·g for high-rank normal coal, which is higher than the other three kinds of coal. Therefore, it must be the first to be adsorbed. When the adsorption capacity is 25.0 cm3/g, the endothermic heat of the unit isosteric enthalpy of desorption is 0.302 kJ·mol−1·cm−3·g for middle-rank deformed coal, which is lower than that of the other three kinds of coal. Therefore, it must be the first to be desorbed.