Experimental Investigation on Strain Changes during CO₂ Adsorption of Raw Coal Sample: Temperature and Effective Stress

Abstract

Through laboratory simulation experiments, this paper studies the influence of different temperature and stress conditions on strain changes of raw coal samples induced by the CO2 adsorption with tri-axial creep-seepage and adsorption-desorption experimental system. Comparing and analyzing the experimental results, the study shows that: (1) within a certain time, the axial and radial strain of the raw coal sample induced by CO2 adsorption both show a growing trend as the adsorption time increases and the strain of the raw coal sample for CO2 adsorption is obvious anisotropy; (2) at the same point in time, the greater the axial effective stress, the smaller the axial strain increasing rate of the loaded coal sample during CO2 adsorption process and the smaller the value of axial deformation; (3) during the adsorption process, the volume strain of raw coal sample decreases with the increasing of temperature, namely, the adsorption capacity of raw coal sample decreases with the increasing of temperature.

Keywords

• raw coal sample
• CO₂ adsorption
• effective stress
• temperature effect
• volume strain