Super-critical CO2 saturation-induced mechanical property alterations in low rank coal: An experimental study

Abstract

The adsorption of carbon dioxide (CO2) into the coal matrix during CO2-enhanced methane recovery causes significant alterations to the coal mass chemical and physical structures, causing modifications to coal's mechanical properties. Hence, the main objective of this study is to investigate the effects of sequestrated CO2 phase condition on coal strength. A series of unconfined compressive strength tests was conducted on Australian brown coal samples, saturated under various CO2 pressures (2-10 MPa) at 35 °C using an advanced acoustic emission (AE) system and optical 3D deformation analysis. According to the results, super-critical CO2 has the ability to cause a greater reduction of strength..