Experimental research on adsorption characteristics of N2, CH4, and CO2 in coal under different temperatures and gas pressures

The coal deformation was induced by the gas adsorption of N-2, CH4, and CO2. However, the differences between different gas adsorption performances and the deformation mechanism of coal need to be further studied. In this study, the experiments were conducted using self-developed equipment to reveal the adsorption characteristics of different gases. The results showed that the gas adsorption capacity followed the sequence of CO2 > CH4 > N-2. The gas adsorption capacity was negatively correlated with temperature. The maximum decrease in adsorption capacity (23.70%) was N-2. The gas adsorption capacity was positively correlated with gas pressure. The maximum increase in gas adsorption capacity (232.79%) was N-2. Correspondingly, the coal deformation of CO2 was the largest, and that of N-2 was the smallest. The maximum decrease in deformation (31.09%) was CO2 during the temperature increase. The initial coal deformation rates of N-2, CH4, and CO2 were 0.060, 0.091, and 0.042 mm center dot h(-1), respectively. The maximum increase of deformation (234.65%) was CH4 with the gas pressure increase. The initial coal deformation rates of N-2, CH4, and CO2 were 0.024, 0.045, and 0.016 mm center dot h(-1), respectively. This work guided further clarifying the mechanism of different gases' adsorption capacity and coal deformation.