Effect of gas adsorption on breakage energy of tectonic coal particles

Abstract

Coal breakage energy can be reduced using gas adsorption. The mechanism by which gas-bearing tectonic coal breaks down is critical for preventing coal and gas outbursts. For tectonic coal particles from two coal mines with a size range of 2–3 mm, a total of 67 sets of crushing experiments were performed under various gas adsorption pressure (0.5–4.0 MPa) and desorption duration (1–240 min) conditions. The fractal theory was used to analyze the particle size distributions of the fragments. The results show that as the adsorption pressure and desorption duration increase, the surface work, which is the ratio of breakage energy to the new surface area, decreases and increases, respectively. Surface work is reduced in proportions ranging from 1.45% to 37.33%. When the pore characteristics are combined with the gas adsorption volume, we confirm that the reduction in surface work (Δγb) is primarily due to gas adsorbed in micropores with a size <1.5 nm. Δγb increases exponentially with the increase in gas adsorption volume (Vt), which can be described as Δγb = λ(eκVt − 1). λ and κ are the material parameters.