Anisotropy and Hysteresis of Coal Dynamic Deformation During Adsorption and Desorption
摘要
Coal deformation-induced by adsorption/desorption is dynamic and anisotropic, influenced by various factors, such as pressure, temperature, and gas type. This paper investigates the dynamic deformation of coal during the adsorption–desorption process and analyzes the anisotropic and hysteretic characteristics. Results show that maximum deformation is reduced by approximately half with every 10 °C increase above 40 °C, and nearly doubles with each 1 MPa pressure increase. The swelling of CO2 at adsorption equilibrium is twice that of CH4, and almost 4 × that of N2. During desorption, shrinkage and desorption gas are approximately linear. Anisotropy coefficients increase initially, then decrease with adsorption, stabilizing around 2. During desorption, anisotropy coefficients generally decrease. The anisotropy coefficient of CO2 is higher than that of CH4 and N2, and all show a tendency to increase with equilibrium pressure. Cumulative hysteresis deformation decreases with the increasing temperature, even reversing at higher temperatures. CO2 exhibits significantly higher hysteresis than CH4 and N2. These findings offer valuable insights for engineering applications.