Deformation Rupture And Coalescence Micro-Characteristics Of Drops In Sinusoidal AC Field

Electrostatic coalescence has the advantages of increasing separation efficiency, reducing footprint, decreasing energy consumption, etc. Therefore, it can provide a good solution for dehydration of high water-cut crude oil and offshore production platform. However, electrostatic coalescence is influenced by many and complex factors and needs further study. This paper carries out experiment to study the deformation, movement, rupture of single drop and coalescence characteristics of pairs of drops in sinusoidal alternating current (AC) electric field with frequency range from 50 to 400Hz. Combining with theories, it deeply analyzes how the electric field strength and frequency, oil viscosity, interfacial tension influence drops'characteristics of deformation, rupture and coalescence characteristics. It draws major conclusions as following:At the range of all factors, the higher the field frequency, the higher the oil viscosity and the smaller the interfacial tension, the lower the extension deformation range of single drop. Ellipsoid drops'eccentricity is approximately proportionate to electric field strength to the power of N ( 1.7 55°drops rotate to a certain angle and then coalesce, and the biggest attracting and coalescing angle observed is about 74.5°and 68.5°respectively. Only whenαin the vicinity of 90°, drops will repel each other obviously. In AC electric field there is almost non-occurrence of coalescence on drop chains. The field with higher frequencies seemingly generates more stable chains. Sudden reduction of electric field strength may destroy drop chains to some extent as well as turbulence disturbance. Meantime, the former may improve coalescence to some degree.