Abstract:

In order to effectively control coal and gas outburst disasters, given the important role of gas diffusion coefficient in determining coal seam gas content, a self-developed gas-containing coal freezing response device was adopted to measure gas desorption and diffusion capacity at temperature of 0, -10, -20, -30 ℃ and adsorption equilibrium pressure of 0.5, 1.0, and 1.5 MPa. And data of classical diffusion model and two dynamic diffusion models were compared with experimental data. The results show that low temperature affects increase of free energy on coal surface, and thermal movement of gas molecules reduces, indicating that low temperature inhibits gas desorption and diffusion in coal. According to the comparison between simulation data of three diffusion models and experimental data, two dynamic diffusion models are better than classical diffusion model, and their exponential function model is better than power function model. Gas diffusion coefficient undergoes two stages of rapid decline and slow decline under influence of temperature.

Key words: low temperature environment, gas desorption and diffusion, diffusion model, compatibility, diffusion coefficient