Pore structure characteristics and fractal structure evaluation of medium- and high-rank coal

The presence of gas content in medium- and high-rank coal poses a threat to safety production. Safe extraction is based on correct understanding the pore structure coal. This work investigates characteristics evaluates their fractal structure. samples were collected from Huainan Coalfield Qinshui Coalfield, divided into four types, according difference surface bright characteristics. Through adopting low-temperature liquid nitrogen adsorption desorption, applying Kelvin equation, we obtain main types size distribution various briquettes. Electron microscope scanning scientific analysis used for special desorption curves hysteresis find dynamic reason. According different mechanism Frenkel–Halsey–Hill-based model, with P/ P 0 = 0.4 as dividing point dimension analysis, classified five grades. evaluation results are consistent curve analysis.