Xu Jiafang, Chen Zhe, Liu Jinxiang, Sun Zening, Wang Xiaopu, Zhang Jun
University of Petroleum (East China), Qingdao, China; National Engineering Laboratory for Subsea Equipment Testing and Detection Technology, China.
University of Petroleum (East China), Qingdao, China.
J Mol Graph Model. 2017 Aug;75:403-412. doi: 10.1016/j.jmgm.2017.03.022. Epub 2017 Apr 4.
Gas hydrate is not only a potential energy resource, but also almost the biggest challenge in oil/gas flow assurance. Inorganic salts such as NaCl, KCl and CaCl are widely used as the thermodynamic inhibitor to reduce the risk caused by hydrate formation. However, the inhibition mechanism is still unclear. Therefore, molecular dynamic (MD) simulation was performed to study the dissociation of structure I (SI) methane hydrate in existence of inorganic salt aqueous solution on a micro-scale. The simulation results showed that, the dissociation became stagnant due to the presence of liquid film formed by the decomposed water molecules, and more inorganic ions could shorten the stagnation-time. The diffusion coefficients of ions and water molecules were the largest in KCl system. The structures of ion/HO and HO/HO were the most compact in hydrate/NaCl system. The ionic ability to decompose hydrate cells followed the sequence of: Ca>2K>2Cl>2Na.
气体水合物不仅是一种潜在的能源，也是油气流动保障领域几乎最大的挑战。氯化钠、氯化钾和氯化钙等无机盐被广泛用作热力学抑制剂，以降低水合物形成所带来的风险。然而，其抑制机制仍不明确。因此，进行了分子动力学（MD）模拟，以在微观尺度上研究在无机盐水溶液存在下结构I（SI）甲烷水合物的分解。模拟结果表明，由于分解的水分子形成液膜，分解过程会停滞，更多的无机离子可以缩短停滞时间。离子和水分子的扩散系数在氯化钾体系中最大。水合物/氯化钠体系中离子/HO和HO/HO的结构最紧密。离子分解水合物晶胞的能力顺序为：Ca>2K>2Cl>2Na。
