Study on energy variation of coal containing gas during low temperature adsorption process

Abstract

In order to obtain the energy change rule in coal adsorbing methane process, methane adsorption experiments were carried out with the temperature of 30 ℃, 15 ℃, 0 ℃, -15℃, -30 ℃, -45 ℃ and the initial adsorption pressure of 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa by the high and low temperature intelligent adsorption experiment chamber. The results show that increasing the gas injection pressure and decreasing the adsorption temperature are two important factors that affect the increase of temperature variation in the process of methane adsorption; the surface free energy of coal samples with a certain mass decreases and the heat increases before and after methane adsorption, and the difference increases gradually due to the increase of methane pressure; in the process of coal adsorbing methane, either pressure boost or temperature drop will increase the coal temperature variation, it is essentially a phenomenon that methane molecular potential energy of coal surface free energy is converted into heat value to maintain the overall energy balance.

Keywords

• coal containing gas
• low temperature
• increasing pressure
• gas adsorption
• surface free energy
• quantity of heat