Abstract High-frequency pulsed alternating current field (HFPACF) has attracted attentions owing to its excellent performances of eliminating short circuit, saving energy and reducing environmental pollution. To study the coalescence mechanism of aqueous drops in water-in-oil (W/O) emulsions under HFPACF, micro-behavior of dispersed drops for W/O emulsion was monitored by using a self-designed micro-visual model and coalescence mechanism was analyzed by discussing effects of pulse amplitude, pulse frequency, pulse width ratio, demulsifier concentration, aqueous mass ratio of emulsion, and different model oil emulsions. The results show that the dispersed drops coalesce under the action of electric field, and the particle size of dispersed drops increases with the increase of pulse frequency and amplitude. When the pulse frequency or amplitude reach to a critical value, aqueous drops are driven to form water string or water channel between two electrodes which hinders further drops coalescence in other areas. However, with the increase of pulse width ratio, the size of dispersed drops increases slowly. The optimum pulse frequency and pulse amplitude are obtained at 3.9 kV and 4.21 kHz, respectively, the optimal pulse width range is 54.9%-84.4%. When the concentration of demulsifier is 60 mg/L, the synergistic demulsification effect achieves the highest performance. When the aqueous mass ratio of emulsion reaches a high level (over 30%), which means the drops in emulsion have big size, the coalescence performance under the same electric field strength is great. Also, it is discovered that the dispersed drops in Yongping model oil emulsion have difficulty in forming water chains, since there are much asphaltenes and resins in the water-oil interface leading to high strength of film. For Shuanghe oil emulsion drops are prevented from coalescing, because it contains a mass of paraffin, which can stabilize emulsion at low temperature.

中文翻译：

---

高频脉冲交流场下油包水乳液中水滴的聚结行为

摘要 高频脉冲交流电场(HFPACF)以其消除短路、节约能源、减少环境污染等优异性能而备受关注。为研究 HFPACF 油包水 (W/O) 乳液中水滴的聚结机理，使用自行设计的微观视觉模型监测了 W/O 乳液分散液滴的微观行为，并采用了聚结机制。通过讨论脉冲幅度、脉冲频率、脉冲宽度比、破乳剂浓度、乳液含水质量比和不同模型油乳液的影响进行分析。结果表明，分散的液滴在电场作用下聚结，分散液滴的粒径随着脉冲频率和幅度的增加而增大。当脉冲频率或振幅达到临界值时，驱动水滴在两个电极之间形成水串或水通道，阻碍水滴在其他区域进一步聚结。然而，随着脉宽比的增加，分散液滴的尺寸缓慢增加。最佳脉冲频率和脉冲幅度分别在3.9 kV和4.21 kHz获得，最佳脉宽范围为54.9%-84.4%。当破乳剂浓度为60mg/L时，协同破乳效果达到最高。当乳液的含水质量比达到较高水平（30%以上）时，即乳液中的液滴尺寸较大，在相同电场强度下的聚结性能就很好。还，发现永平模型油乳液中分散的液滴难以形成水链，因为水-油界面存在大量沥青质和树脂，导致膜强度高。双河油乳化液滴不聚结，因为它含有大量的石蜡，可以在低温下稳定乳化液。