CH4水合物生长速率影响因素的分子动力学模拟

采用分子动力学模拟，研究了温度、压力和电解质溶液对CH4水合物生长速率的影响.通过分析势能、均方位移、氢键数量、径向分布函数和四体结构有序参数，表征了CH4水合物的生长动力学.模拟结果表明，降低温度和提高压力可以显著提高CH4水合物的生长速率.当压力恒为15MPa，温度高于290K时，势能升高，CH4水合物晶体发生分解；温度由290K降至260K时，势能降低，CH4水合物持续生长.当温度恒为275K，压力由3MPa增至50MPa时，CH4水合物生长速率提高12%.此外，电解质离子的存在抑制了水合物的生长，电解质溶液浓度由1.5wt%增加到3.5wt%时, CH4水合物生长速率降低25%.

Molecular dynamics simulation of factors affecting the growth rate of CH4 hydrate

The effects of temperature, pressure and electrolyte solution on the growth rate of CH4 hydrate were studied by using molecular dynamics simulation. The growth kinetics of CH4 hydrate was characterized by analyzing potential energy, mean square displacement, number of hydrogen bonds, radial distribution function, and four-body structure order parameters. The simulation results show that decreasing the temperature and increasing the pressure can significantly increase the growth rate of CH4 hydrate. When the pressure is constant at 15MPa and the temperature is higher than 290K, the potential energy increases and the CH4 hydrate crystals decompose; when the temperature decreases from 290K to 260K, the potential energy decreases and CH4 hydrate continues to grow. When the temperature is constant 275K and the pressure is increased from 3MPa to 50MPa, the growth rate of CH4 hydrate increases by 12%. In addition, the presence of electrolyte ions inhibit the growth of hydrates. When the electrolyte solution concentration is increased from 1.5wt% to 3.5wt%, the growth rate of CH4 hydrate is reduced by 25%.