Ma Qianli, Wang Chuanshuo, Lu Yingda, Liu Yang, Lv Xiaofang, Zhou Shidong, Gong Jing
Jiangsu Key Laboratory of Oil and Gas Storage and Transportation Technology, Changzhou University, Changzhou, Jiangsu 213164, China.
Hildebrand Department of Petroleum & Geosystems Engineering, The University of Texas at Austin, Austin, Texas 78712, United States.
ACS Omega. 2023 Feb 15;8(8):7546-7554. doi: 10.1021/acsomega.2c06809. eCollection 2023 Feb 28.
This study explores how the micro-distribution change of wax crystals from the continuous oil phase to the oil-water interface mitigates the macro wax deposition of an emulsion. Two types of interfacial actions between wax crystals and water droplets, interfacial adsorption and interfacial crystallization, which were induced by two different emulsifiers, sorbitan monooleate (Span 80) and sorbitan monostearate (Span 60), respectively, were detected by differential scanning calorimetry and microscopy observation. The wax interfacial crystallization promoted by Span 60 resulted in the wax being nucleated directly at the oil-water interface prior to the continuous oil phase, conferring the nascent wax crystals and water droplets to be combined as coupled particles. The utilization of the wax interfacial crystallization behavior to hinder wax deposition of an emulsion was further explored. When the coupled wax crystal-water droplet particles were formed during the wax deposition process, water droplets acted as wax crystal carriers, entraining these nascent wax crystals to disperse in the emulsion, which significantly reduced the amount of wax crystals available to form the network of the deposit. In addition, this change also led to the basic structural units in the wax deposit evolving from wax crystal clusters/networks to water droplet flocs. The study elucidates that through adjusting the dispersion of wax crystals from the oil phase to the oil-water interface, water droplets could act as a functional component to tailor the properties of the emulsion or resolve related flow and deposition problems in pipeline transportation.
本研究探讨了蜡晶从连续油相到油水界面的微观分布变化如何减轻乳液的宏观蜡沉积。通过差示扫描量热法和显微镜观察，检测了分别由两种不同乳化剂山梨醇单油酸酯（Span 80）和山梨醇单硬脂酸酯（Span 60）诱导的蜡晶与水滴之间的两种界面作用，即界面吸附和界面结晶。由Span 60促进的蜡界面结晶导致蜡在连续油相之前直接在油水界面成核，使新生的蜡晶和水滴结合成耦合颗粒。进一步探索了利用蜡界面结晶行为来阻碍乳液蜡沉积的方法。当在蜡沉积过程中形成耦合的蜡晶 - 水滴颗粒时，水滴充当蜡晶载体，携带这些新生的蜡晶分散在乳液中，这显著减少了可用于形成沉积物网络的蜡晶数量。此外，这种变化还导致蜡沉积物中的基本结构单元从蜡晶簇/网络演变为水滴絮凝物。该研究表明，通过调节蜡晶从油相到油水界面的分散，水滴可以作为一种功能成分来调整乳液的性质或解决管道输送中相关的流动和沉积问题。
