高压条件天然气水合物形成过程的分子动力学模拟

Molecular Dynamics Simulation of Gas Hydrate Formation Process under High Pressure Condition

天然气水合物作为一种潜在的清洁能源已经引起广泛关注,为了更好地开发利用该资源必须对其形成机理进行充分了解和精准分析。本工作采用分子动力学方法旨在揭示1 GPa条件下天然气水合物的形成及结构演化。通过径向分布函数、均方根位移及环统计手段对研究体系的甲烷分子和水分子的行为及其周围环境进行分析。模拟结果表明,研究范围内温度对天然气水合物的结构影响不大,但对天然气水合物的生成数量具有明显的影响。环统计分析表明研究体系生成的五元环数量众多且相互联接而生成的六元环数量较少且孤立存在,两者数量比约为5:1。

As a potential clean energy source, natural gas hydrate (NGH) has attracted wide attention. Sufficient understanding and accurate analyses for the complex formation mechanism in a natural gas hydrate system have to occur before the hydrate untilization. In this paper, molecular dynamics simulation is carried out to explore the formation and structure patterns under 1 GPa conditions. Radial distribution function, mean square displacement and ring statistics provide important insights into the behavior of the methane and water molecules present in the system. The simulations show that the structure of nature gas hydrate keeps unchanged at different temperatures, while the amount of gas hydrate is significantly influenced by temperature. Ring statistics were used to interpret that the five rings number is more and all connected, a small number of six rings for isolated form, the ratio is 5:1.