THE CHARACTERISTICS OF GAS ADSORPTION IN MICROPORES AND ITS INFLUENCE ON COAL AND GAS OUTBURST

In order to study the relationship between the power source of coal and gas outburst and the adsorption in micropores, low temperature nitrogen adsorption experiment was carried out in the laboratory. The nonlinear fitting method was used to analysis the adsorption data to determine the relative pressure, at which the micropore filling phenomenon had been completed. The density of methane under the environmental conditions of 298.15 K and 0.1 MPa was calculated with the equation of SRK, equal to 0.000 65g/cm(3). In the absence of gas outburst, the pressure generated in gas desorption process is 0.1731 similar to 0.2741 MPa in theory, which is greater than the standard atmospheric pressure of 0.1 MPa. By analyzing the characteristics of gas flow in coal pores, the equation for the gas outburst pressure was proposed by us. In addition, the characteristic energy of adsorption and differential adsorption work were calculated based on the micropore filling theory. The characteristic energy of adsorption is 5.08 similar to 5.84 kJ/mol, which is greater than the differential adsorption work 3.70 similar to 3.91 kJ/mol. For the occurrence of gas outburst, the coal has at least an energy exchange with the external environment of the adsorption characteristic energy.