This study used the cylinder raw coal samples from Tunliu coal mine and Sihe coal mine to carry out the displacement of CH₄ with CO₂ experiment under the different injection pressures. Analyzed the gas adsorption characteristics in the experiment and the influence of injection pressures on the replacement of with CO₂, and proposed that replacement effect was better at low pore pressure. The results are as follows. Adsorption capacity of CO₂ is stronger than that of CH₄ under the same condition in the process of displacement; CH₄ volume ratio decreases with injection pressure decreasing, while CO₂ volume ratio shows the opposite trend; When the confining pressure is 8 MPa, the CH₄ output ratio reduces with linear relation and the replacement ratio of CO₂ reduces with exponential relation as injection pressure increases, and indicating that the replacement is better at low injection pressure in this displacement experimental; The replacement effect of meager lean coal sample is better than anthracite under the same conditions in this experimental.

CO₂  /  CH₄  /  replacement  /  output ratio  /  replacement ratio