The impact of temperature and pressures on the efficiency of CH4 replacement in CO2-injected coal

his study examines the effects of temperature (T), CO2 injection pressure (P0), and initial CH4 adsorption equilibrium pressure (P1) on the CH4 replacement rate (η) following CO2 injection into anthracite coal. Using experimental data on the CH4 replacement rate under varying conditions, a response surface methodology (RSM) was applied to evaluate the individual and interactive influences of these param- eters on the CH4 replacement process. The results demonstrate that the CH4 replacement rate increases with both temperature and CO2 injection pressure but decreases with higher initial CH4 adsorption equilibrium pressure. Furthermore, the sensitivity of the CH4 replacement rate to the individual factors is ordered as P1 > P0 > T. The interaction effects between two factors are ranked as follows: fP1 and P0g > fP1 and Tg > fP0 and Tg. These findings provide valuable insights for optimizing CO2-ECBM technology and refining operational parameters.