Abstract
A series of isothermal adsorption experimental data of long flame coal, fat coal, lean coal and lean coal in Ordos Basin are used to verify a temperature-pressure-adsorption equation, and the functional relationship between adsorption equilibrium pressure and temperature was discussed. The enthalpy of the gas adsorption process is calculated by the Clausis-Clapperon equation. The concept and calculation method of unit isosteric adsorption enthalpy is presented. The adsorption process of the coal is an exothermic process because its negative enthalpy. The unit isosteric adsorption enthalpy decreases with the increase of adsorption capacity because of the energy inhomogeneity on the coal surface. Because of the exothermic adsorption process, so the adsorption occurs at a higher energy site first in order to release more energy. The higher rank coal has a larger unit isosteric adsorption enthalpy, and there must be a larger adsorption capacity. The adsorption capacity of high rank coal decreases rapidly with the increase of adsorption temperature, but the low rank coal decreases less.

Keywords
Clausius-Clapeyron equation; Temperature-pressure-adsorption equation; Isosteric enthalpy of adsorption; Unit isosteric enthalpy of adsorption; Gas adsorption; Coal rank

Cite this paper
HAO Jing-Yuan, LI Dong, Ma Qinghua, ZHANG Xue-Mei, Application of temperature-pressure-adsorption equation in calculating the adsorption enthalpy of coal seam , SCIREA Journal of Physics. Volume 4, Issue 4, August 2019 | PP. 111-125.

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