Binary-Component Gas Adsorption Isotherm Experiments and Their Significance to Exploitation of Coalbed Methane

The adsorption isotherm experiments of CH₄-CO₂ and CH₄-N₂ binary-component gas were carried out respectively, and the variation regularity of each component concentration in the experiments were analyzed. The experiment results indicate that the relative concentration of CH₄ component in absorbed phase increases gradually while the relative concentration of N₂ component in absorbed phase decreases gradually in the adsorption isotherm experiment of CH₄-N₂ binary-component gas. Whereas the relative concentration of CO₂ component in absorbed phase shows a gradual increase and the relative concentration of CH₄ component shows a gradual decrease in the adsorption isotherm experiment of CO₂-CH₄ binary-component gas. These results confirm that CO₂ occupies the predominant position and N₂ locates at inferior position as they compete for adsorption with CH₄ respectively. Therefore, CO₂-injection can replace or displace coalbed methane and enhance methane recovery more effectively than N₂-injection.