ABSTRACT

Uncontrolled decomposition of natural gas hydrate may lead to serious marine geological disasters and air pollution. The model of natural gas hydrate and lecithin was established. The stability mechanism of lecithin to structure hydrate was studied by molecular dynamics simulation. The consistent valence force field (CVFF) and TIP3P potential models are used to define the interaction between CH₄-CH₄ and water-water species, respectively. The simulations are performed on a combination of a 2 × 2 × 4 unit cell of sI hydrate and a water liquid phase with lecithin. The results of the simulations indicate that lecithin molecules adsorb on the hydrate surface with their hydrocarbon chains crossing and forming a net structure, easily producing the hydrate memory effect, which will narrow the available space for hydrate methane and water movement. Compared to the pure water-hydrate model, the mean square displacement (MSD) values of hydrate methane and water molecules are much lower, indicating that the hydrate dissociates more slowly.

摘要

天然气水合物不受控制的分解可能导致严重的海洋地质灾害和空气污染。建立了天然气水合物和卵磷脂模型。通过分子动力学模拟研究了卵磷脂对水合物结构的稳定机理。一致价力场 (CVFF) 和 TIP3P 势模型用于定义 CH ₄ -CH ₄之间的相互作用和水-水物种，分别。模拟是在 sI 水合物的 2 × 2 × 4 晶胞和具有卵磷脂的水液相的组合上进行的。模拟结果表明，卵磷脂分子吸附在水合物表面，其烃链交叉形成网状结构，容易产生水合物记忆效应，从而缩小水合物甲烷和水运动的可用空间。与纯水-水合物模型相比，水合物甲烷和水分子的均方位移 (MSD) 值要低得多，表明水合物离解得更慢。