| A theoretical multi-component gas adsorption model has been developed based on Thermodynamic principles, vacancy solution concept and pure component gas adsorption models. The purpose of the model is to calculate the mixture gas adsorption capacity, which is the key factor in predicting and enhancing the recovery of coal bed methane (CBM). The pure gas data from actual experiments has been used in comparing Langmuir, Toth, Dubinin methods. The best fit model, which is Dubinin-Astakhow (D-A) equation, has been selected for generating pure gas maximum adsorption capacity. A new mixture gas isotherm adsorption model has been generated based on Vapor/Liquid equilibrium theory and vacancy concepts. Three activity coefficient equations, the Margules equation, the Wilson equation and the NRTL equation, have been used in the new method to correlate with the pure gas adsorption experimental data and generate the interaction coefficients between the pure components with vacancy. |
