Abstract

Formation of stable water-in-oil emulsions in light and heavy crude oils was shown to involve the buildup of interfacial layer characterized by increased contents of the main emulsifiers, asphaltenes and resins. An increase in the proportion of asphaltenes in the interfacial layer, nearly 4-fold for the light oil and 1.3-fold for the heavy oil samples, was accompanied by changes in their elemental and structural-group compositions. The proportions of resins in the interfacial layers exceeded by 25–86% those in the original oils. IR-spectroscopic examination revealed increases in the concentration of carboxy and methylene groups in the asphaltenes and resins from the interfacial layer of the light oil and in the concentration of sulfoxide and carboxy groups from the interfacial layer of the heavy sulfurous oil. The dependence of the surface activity of resins and asphaltenes on pH of the aqueous phase was elucidated. Asphaltenes and resins exhibited decreases in interfacial tension (2.3–3.2-fold maximum) in the pH range 10–12 compared to pH range 4–6, which was due to neutralization of their constituent carboxy groups. Reduction of the interfacial tension in the acidic region was attributed to the presence of sulfoxide groups, possessing the properties of weak bases, in the emulsifiers.

中文翻译：

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油包水乳液界面层中树脂-沥青质组分的组成

摘要

研究表明，在轻质和重质原油中形成稳定的油包水乳液涉及以主要乳化剂、沥青质和树脂含量增加为特征的界面层的建立。界面层中沥青质的比例增加，轻油样品的近 4 倍和重油样品的 1.3 倍，伴随着它们的元素和结构组组成的变化。界面层中树脂的比例超过了原始油中的 25-86%。红外光谱检测表明，轻油界面层的沥青质和树脂中羧基和亚甲基的浓度增加，重亚硫油界面层的亚砜和羧基的浓度增加。阐明了树脂和沥青质的表面活性对水相 pH 值的依赖性。与 pH 范围 4-6 相比，沥青质和树脂在 10-12 的 pH 范围内表现出界面张力的降低（最大 2.3-3.2 倍），这是由于它们的组成羧基被中和。酸性区域界面张力的降低归因于乳化剂中亚砜基团的存在，具有弱碱的性质。