This study aims to analyze the dynamics of demulsification in a water-in-oil emulsion flowing in a closed-loop circuit by monitoring changes in its rheological properties. The composition of the emulsion consisted of naphthenic mineral oil (viscosity: 0.396 Pa·s), Span 80, and distilled water, while an amine-initiated polyol block copolymer demulsifier (hydrophilic–lipophilic balance, HLB 13) was used at concentrations up to 100 ppm. To propose a new procedure for assessing process dynamics, we adjusted the parameters of a first-order function to fit the dynamic viscosity data obtained from experiments involving sequential disturbances in demulsifier concentration. We evaluated the effects of flow rate (40–120 mL/min), dispersed phase fraction (30–50 vol %), temperature (30–50 °C), and shear promoted by a pump on the dynamics of demulsification model parameters. The results reveal that elevated temperatures and higher water content accelerate the reduction of viscosity, likely due to increased droplet collision frequency and enhanced coalescence, as the reduced continuous phase viscosity promotes faster demulsifier migration to the droplet interface and the breakdown of stabilizing films. Higher dispersed phase volumes decrease the distance between droplets, further accelerating phase separation. Conversely, strong shear from the pump delays demulsification by producing finer droplets that require longer surfactant action, despite improving demulsifier homogenization. Similarly, while moderate flow rates enhance chemical dispersion, higher flow rates (e.g., 120 mL/min) induce re-emulsification due to excessive fluid shear, which compromises separation efficiency. Additionally, we analyzed flow patterns under conditions where emulsion destabilization occurred, making the kinetic model inapplicable. These findings contribute to a better understanding of in-flow chemical demulsification, improving flow assurance strategies and fostering further research in this crucial area of oil production and transportation.

中文翻译：

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流动条件对高粘度乳化液流中化学破乳动力学的影响

本研究旨在通过监测其流变特性的变化来分析在闭环回路中流动的油包水乳液中的破乳动力学。乳液的成分由环烷基矿物油（粘度：0.396 Pa·s）、Span 80 和蒸馏水组成，而胺引发的多元醇嵌段共聚物破乳剂（亲水-亲油平衡，HLB 13）的浓度高达 100 ppm。为了提出一种评估过程动力学的新程序，我们调整了一阶函数的参数，以拟合从涉及破乳剂浓度顺序干扰的实验中获得的动态粘度数据。我们评估了流速 （40-120 mL/min）、分散相分数 （30-50 vol %）、温度 （30-50 °C） 和泵促进的剪切对破乳模型参数动力学的影响。结果表明，高温和较高的含水量加速了粘度的降低，这可能是由于液滴碰撞频率增加和聚结增强，因为降低的连续相粘度促进了破乳剂更快地迁移到液滴界面和稳定膜的分解。较高的分散相体积会减小液滴之间的距离，从而进一步加速相分离。相反，泵的强剪切力会产生更细的液滴，尽管改善了破乳剂的均质性，但需要更长的表面活性剂作用，从而延迟破乳。同样，虽然中等流速可增强化学品分散，但较高的流速（例如 120 mL/min）会因流体剪切力过大而诱导再乳化，从而影响分离效率。 此外，我们分析了乳化不稳定条件下的流动模式，使动力学模型不适用。这些发现有助于更好地了解流动化学破乳，改进流动保障策略，并促进石油生产和运输这一关键领域的进一步研究。