Study on CO2 adsorption and diffusion law of coal under different temperatures and pressures

Abstract

In order to overcome the difficulty of gas mining when coal mining depth increased, the adsorption and diffusion laws of CO2 molecules at different temperatures and pressures were simulated by using the simulation software Materials Studio; the relationship between CO2 mean square displacement and time was simulated based on molecular dynamics. The results showed that in the isothermal adsorption curves of 15 ℃, 25 ℃, 30 ℃ and 35 ℃, the adsorption capacity of CO2 decreased gradually when temperature increased. It showed that CO2 was conducive to geological storage at low temperatures; the values of self-diffusion coefficient, corrected diffusion coefficient and transfer diffusion coefficient of CO2 in coal increased when temperature and pressure increased. The maximum value was reached at 35 ℃ and 3.5 MPa.

Keywords

• co2
• molecular dynamics
• materials studio
• microscopic simulation
• adsorption diffusion