Prediction of Supercritical Methane Adsorption in Deep Coal Seam

In order to predict the supercritical methane adsorption in deep coal seam, the adsorption potential model and the equal adsorption heat model were constructed.The error of this two models in predicting the supercritical methane adsorption was investigated.According to isothermal adsorption data at the temperature of 300.5 K and 323.0 K, the supercritical methane adsorption at the temperature of 313.0 K was predicted by two models respectively, and compared with the measured values.The results showed that the pressure should be corrected in the study of supercritical adsorption; the equal adsorption heat model can be used in the field of supercritical adsorption, the average relative error of the equal adsorption heat model is 3.17% and the average relative error of the adsorption potential model is 3.60% when the pressure is from 6.0 MPa to 7.5 MPa; with the increase of pressure, the prediction error of the adsorption potential model decreases gradually while the prediction error of the other model is increasing; when the pressure is below 6.99 MPa, the equal adsorption heat model is better in prediction; when the pressure is beyond 6.99 MPa, the adsorption potential model about prediction result is better. In totally, the prediction error of two models are within the engineering allowable error range, but the adsorption potential model is simple and requires less data, and it has better applicability in engineering application.