Simulation of gas molecules permeation diffusion in coal structure and gangue slit structure

Abstract

In order to analyze the permeation law of different gases in gangue mountain, the structural models of gas molecules such as SO2, NO2, O2, N2 and O3 as well as coal and gangue slit were constructed, and the grand canonical Monte Carlo method and molecular dynamics simulation method were used to calculate the permeation of five gas molecules in coal and gangue slit model under different environment conditions. The results show that the total energy of gas molecules adsorbed on two models increases with pressure and then tends to level off, and each gas molecule is mainly physically adsorbed, and the order of the strongest adsorption capacity is in the order of SO2>O2>O3>N2>NO2, with the strongest adsorption of SO2 and the strongest diffusion of NO2. By comparing the mixing and diffusion effects among the gases, it was found that the aggregation phenomenon occurred among the molecules of each gas after mixing, and the concentration distribution and the size of the permeation coefficient followed that O2+N2+SO2+NO2+O3>SO2+NO2+O3>O2+N2>single component gas, indicating that there is a certain interaction between the gas molecules, which facilitates the diffusion, weakens the adsorption and finally enhances the inter-gas permeability. At the same time, it also confirms that the more components of the gas mixture, the stronger the permeation effect of each gas molecule.

Keywords

• coal gangue slit
• grand canonical monte carlo
• molecular dynamics simulation
• diffusion
• penetration capacity