多元体系油水界面上常见表面活性剂行为的分子动力学模拟
发布时间：2018-09-04 08:30
【摘要】：采用分子动力学模拟研究了以十二烷基苯磺酸钠(SDBS)为代表的阴离子型表面活性剂,以十二烷基三甲基溴化铵(DTAB)为代表的阳离子型表面活性剂,以壬基酚聚氧乙烯醚(NPE)为代表的非离子型表面活性剂,以十二烷基二甲基甜菜碱(Betaine)为代表的两性表面活性剂及空白实验.模拟了表面活性剂在油水界面上的行为,考察了表面活性剂分子与石油分子之间的径向分布函数(RDF)、石油分子在竖直方向的均方位移(MSD)、油水界面张力(IFT)、石油层与岩石层之间的相互作用能、石油层的相对浓度在竖直方向的分布及石油分子质心位置随模拟时间的变化关系等,讨论了不同表面活性剂的洗油性能.结果表明:(1)SDBS,NPE和Betaine分子初始状态下呈近似的规律排列,非极性端部分插入油相中,极性端延伸进入水相中;随后表面活性剂的极性端表现出聚集趋势,逐渐形成一个外部亲油内部亲水的一个胶束状粒子,粒子随模拟的进行逐渐融入到油层当中;DTAB从开始的近似规则排列逐渐变为无规排列,但是始终保持亲油端插入到油相中,亲水端位于油水界面上.(2)表面活性剂分子与石油分子之间的相互作用强弱顺序为Betaine≈DTABSDBSNPE.(3)由质心高度和动力过程中的图像截图分析,表面活性剂洗油效果的顺序为BetaineSDBSNPEDTABNone.模拟结果与实际的驱油结果一致,从分子层面上解释了不同表面活性剂洗油的规律.
[Abstract]:The anion surfactant represented by sodium dodecylbenzene sulfonate (SDBS) and the cationic surfactant represented by dodecyl trimethylammonium bromide (DTAB) were studied by molecular dynamics simulation. Non-ionic surfactant represented by nonylphenol polyoxyethylene ether (NPE), amphoteric surfactant represented by dodecyl dimethyl betaine (Betaine) and blank experiment. The behavior of surfactants at the oil-water interface was simulated. The radial distribution function between surfactant molecules and petroleum molecules was studied. The interaction energy of (RDF), oil molecules in vertical mean square displacement (MSD), oil-water interfacial tension (IFT), oil layer and lithosphere was investigated. The distribution of the relative concentration in the vertical direction and the relationship between the position of the molecular mass center and the simulation time were discussed. The oil washing performance of different surfactants was discussed. The results show that: (1) at the initial state of SDBS,NPE and Betaine molecules are arranged approximately, the non-polar end is partially inserted into the oil phase, the polar end extends into the water phase, and the polar end of the surfactant shows a tendency of aggregation. A micellar particle gradually formed, which was hydrophilic and hydrophilic inside the outer oil. The particles were gradually integrated into the reservoir with the simulation, and the DTAB gradually changed from approximate regular arrangement to random arrangement, but the oil-friendly end was always inserted into the oil phase. The hydrophilic end is located at the oil-water interface. (2) the order of interaction between surfactant molecules and petroleum molecules is Betaine 鈮，
本文编号：2221553
[Abstract]:The anion surfactant represented by sodium dodecylbenzene sulfonate (SDBS) and the cationic surfactant represented by dodecyl trimethylammonium bromide (DTAB) were studied by molecular dynamics simulation. Non-ionic surfactant represented by nonylphenol polyoxyethylene ether (NPE), amphoteric surfactant represented by dodecyl dimethyl betaine (Betaine) and blank experiment. The behavior of surfactants at the oil-water interface was simulated. The radial distribution function between surfactant molecules and petroleum molecules was studied. The interaction energy of (RDF), oil molecules in vertical mean square displacement (MSD), oil-water interfacial tension (IFT), oil layer and lithosphere was investigated. The distribution of the relative concentration in the vertical direction and the relationship between the position of the molecular mass center and the simulation time were discussed. The oil washing performance of different surfactants was discussed. The results show that: (1) at the initial state of SDBS,NPE and Betaine molecules are arranged approximately, the non-polar end is partially inserted into the oil phase, the polar end extends into the water phase, and the polar end of the surfactant shows a tendency of aggregation. A micellar particle gradually formed, which was hydrophilic and hydrophilic inside the outer oil. The particles were gradually integrated into the reservoir with the simulation, and the DTAB gradually changed from approximate regular arrangement to random arrangement, but the oil-friendly end was always inserted into the oil phase. The hydrophilic end is located at the oil-water interface. (2) the order of interaction between surfactant molecules and petroleum molecules is Betaine 鈮，
本文编号：2221553
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