Sharma Ekta, Shown Biswajit, Sulakhe Swapnil, Naik Vijay M, Thaokar Rochish M, Juvekar Vinay A
Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India.
Refining R&D Centre, Reliance Industry Limited, Jamnagar 361142, Gujarat India.
ACS Omega. 2024 Mar 11;9(11):12768-12778. doi: 10.1021/acsomega.3c08554. eCollection 2024 Mar 19.
Frequent desalter upsets in the refineries processing opportunity crude oils are often triggered by a rapid and uncontrollable buildup of the rag layer, a thick water-in-oil emulsion, at the oil-brine interface. This is caused by spontaneous emulsification of brine in oil. This study investigates a unique observation from a spinning drop (SD) tensiometer, revealing the low apparent interfacial tension and rigidity of SD caused by spontaneous emulsification. Fine droplets of brine generated through spontaneous emulsification decorate the SD surface and form a stable, low-energy bilayer. Simulated rag layers using the brines from upset incidences exhibit similar behavior, indicating that spontaneous emulsification is driven by chemical species in brine, which promote osmotic water transport. The rate of rag layer buildup correlates with the rate of spontaneous emulsification, with the temperature coefficient of interfacial tension reduction serving as a sensitive indicator. An imminent upset in the operation can be forecasted by measuring this temperature coefficient, enabling preventive measures.
在加工机会原油的炼油厂中，频繁出现的脱盐装置故障通常是由在油-盐水界面处迅速且无法控制地形成 rag 层（一种浓稠的油包水乳液）引发的。这是由盐在油中的自发乳化引起的。本研究调查了旋转滴（SD）张力计的一个独特观察结果，揭示了自发乳化导致的 SD 表面低表观界面张力和刚性。通过自发乳化产生的细小盐水滴装饰 SD 表面并形成稳定的低能量双层。使用故障事件中的盐水模拟的 rag 层表现出类似行为，表明自发乳化是由盐水中促进渗透水传输的化学物质驱动的。rag 层形成的速率与自发乳化的速率相关，界面张力降低的温度系数作为一个敏感指标。通过测量这个温度系数可以预测操作中即将出现的故障，从而采取预防措施。
