Coalescence and spontaneous emulsification in the presence of asphaltenes

演讲者： Gerald Fuller院士 （美国工程院院士、斯坦福大学化学工程系教授、广州大学杰出兼职教授）

时间：2018年4月3日、周二下午2：00

地点：智能制造工程研究院、系统流变学研究所会议室（计算机实验楼709会议室）

作者：Gerald Fuller, Simone Bochner, Maria Merola

单位：Chemical Engineering, Stanford University, Stanford, CA 94305

作者：Dimitris Vlassopoulos

单位：Department of Materials Science & Technology, University of Crete

In refining operations and in upstream production of oil, water-in-oil emulsions are invariably encountered.  However, complex components of crude oil such as asphaltenes may stabilize these emulsions causing difficulties in separation efficiency and water removal. Here we show the coalescence inhibition caused by asphaltene adsorption for both water-in-oil and oil-in-water emulsions, where the oil phase consists of a simple model of asphaltenes dissolved in toluene. We find that oil-in-water emulsions are less stable than water-in-oil emulsions by using a newly developed instrument where controlled experiments for the coalescence time of a single droplet against an oil/water interface can be measured as a function of asphaltene aging (associated with the adsorption process of asphaltene molecules onto interfaces) and asphaltene concentration. Furthermore, we find that the coalescence time for water droplets exhibits a maximum due to a spontaneous emulsification at the oil/water interface that produces micron-sized droplets consisting of asphaltene-laden water droplets.