气体分子在煤结构与煤矸石狭缝结构中的渗透扩散模拟

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

为了分析不同气体在煤矸石山中的渗透规律,构建了SO_(2)、NO_(2)、O_(2)、N_(2)和O_(3)等气体分子以及煤和煤矸石狭缝的结构模型,采用巨正则蒙特卡罗方法及分子动力学模拟方法计算了5种气体分子在煤和煤矸石模型中不同环境下的渗透作用。研究结果表明:气体分子吸附在2种模型上的总能量均随着压力的升高出现先增大后趋于平缓的规律,且各气体分子以物理吸附为主,吸附能力强弱顺序为SO_(2)>O_(2)>O_(3)>N_(2)>NO_(2),SO_(2)的吸附作用最强,NO_(2)的扩散作用最强;通过对比各气体间的混合扩散效果,发现混合后各气体分子间出现聚集现象,且浓度分布和渗透系数大小都遵循O_(2)+N_(2)+SO_(2)+NO_(2)+O_(3)>SO_(2)+NO_(2)+O_(3)>O_(2)+N_(2)>单一组分气体,说明气体分子间存在一定的相互作用,利于扩散作用,削弱吸附作用,最终增强气体间的渗透能力;同时,也印证了混合气体的组分越多,各气体分子的渗透作用越强。

In order to analyze the permeation law of different gases in gangue mountain,the structural models of gas molecules such as SO_(2),NO_(2),O_(2),N_(2)and O_(3)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 SO_(2)>O_(2)>O_(3)>N_(2)>NO_(2),with the strongest adsorption of SO_(2)and the strongest diffusion of NO_(2).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 O_(2)+N_(2)+SO_(2)+NO_(2)+O_(3)>SO_(2)+NO_(2)+O_(3)>O_(2)+N_(2)>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.