Studies on the normal-to-abnormal emulsion inversion of waxy crude oil-in-water emulsion induced by continuous stirring

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• 作者：Fei Yang ; Chuanxian Li ; ^{lchxian@upc.edu.cn} ; Chao Xu ; Min Song
• 关键词：waxy crude oil ; catastrophic inversion ; multiple emulsion ; continuous stirring ; nonionic surfactant
• 刊名：Journal of Petroleum Science and Engineering
• 出版年：2012
• 期刊代码：33_09204105
• 类别：pw
• 出版时间：January, 2012
• 卷：81
• 期：Complete
• 页码：64-69
• 文件大小：1059 K

摘要

In this paper, the normal-to-abnormal emulsion inversion induced by continuous stirring in a waxy crude oil, water and Triton X-100 emulsion was investigated. The emulsion inversion from the preferred O/W to W/O occurs through the formation of a w/O/W multiple emulsion, in which water from the external phase is continuously included as droplets in the dispersed oil phase drops until a critical dispersed phase value is reached and the inversion takes place. The inversion time, t_inv, is an appropriate parameter to describe the emulsion inversion difficulty. And t_inv increases with increasing emulsifier or NaCl concentrations while decreases with increasing stirring rate, meaning that the emulsion inversion becomes difficult with increasing emulsifier or NaCl concentrations while becomes easy with increasing stirring rate. The influence of 蠁_o on t_inv is complicate due to the increase of emulsion viscosity with increasing 蠁_o. In general, increasing 蠁_o favors the emulsion inversion thus decreasing t_inv. However, the increased emulsion viscosity is adverse for the emulsion inversion thus increasing t_inv. At high stirring rates (鈮?#xA0;1500 rpm), the emulsion viscosity has little influence on the emulsion inversion and then t_inv decreases with increasing 蠁_o; at low stirring rates (鈮?#xA0;750 rpm), the stirring intensity is too low to trigger the emulsion inversion at every value of 蠁_o; at intermediate stirring rates, the value of t_inv is influenced not only by 蠁_o but also by the emulsion viscosity.