Drop-interface electrocoalescence under pulsatile electric fields

被引：0
|
作者：
Li B. [1 ,2 ]
Ren R. [1 ]
Sun Z. [1 ]
Wang Z. [1 ]
Li X. [1 ]
Jin Y. [1 ]
机构：
[1] State Key Laboratory of Heavy Oil, China University of Petroleum (East China), Qingdao, 266580, Shandong
[2] School of Chemical and Process Engineering, University of Leeds, Leeds
来源：
Wang, Zhenbo (wangzhb@upc.edu.cn) | 2018年 / Materials China卷 / 69期
关键词：
Electrocoalescence; Oil-water interface; Pulsatile fields; Secondary droplet;
D O I：
10.11949/j.issn.0438-1157.20171068
中图分类号：
学科分类号：
摘要：
In order to investigate the drop-interface coalescence mechanism under pulsatile electric fields, micro-experiments were conducted on the effect of electrical parameters (electric field intensities, frequencies and waveforms) and physical parameters (surface tension, conductivity, primary droplet size and SiO2 particles) with deionized water as dispersed phase and sunflower oil as continuous phase. The results show that two mechanisms exist, i.e. complete coalescence and partial coalescence, during drop-interface coalescence. The dominant factor is the competition of pumping and necking process. Partial coalescence is enhanced with increasing field strengths, while it is decreased with increasing frequencies. This is resulted from the strength of electrostatic force and the stability of droplets under pulsatile fields. With increasing surfactant concentrations, secondary droplets increase rapidly. When the concentration is higher than that of the critical micelle, secondary droplets decrease slightly. With increasing conductivities and SiO2 concentrations, partial coalescence is enhanced first and then decreases. On the other hand, with increasing primary droplet sizes, partial coalescence increases continuously. Among the waveforms utilized in the experiments, constant DC wave has the highest partial coalescence while sawtooth wave has the lowest. The outcome of this work is potentially useful for optimizing the design of compact and efficient oil-water separators. © All Right Reserved.
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页码：815 / 822
页数：7
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