Effects of cleat performance on strength reduction of coal in CO2 sequestration

Abstract

The natural cleat system in coal is highly important in the CO2 sequestration process as injected CO2 first moves through the cleat system, which eventually changes the coal's permeability and strength. The main objective of this study is to investigate the effects of cleat density and direction on the strength reduction of coal with CO2 adsorption. A series of strength experiments was conducted on non-CO2-saturated and CO2-saturated (1, 2, 3 and 16 MPa) coal samples with two different cleat densities (low-rank lignite and high-rank bituminous) and two different cleat angles (around 20° and 70° to the loading directions). According to the experimental results, CO2 saturation, at up to 3 MPa ..