Electrorheological Characteristic of Heavy Oil Emulsions under High-Frequency/High-Voltage AC Electric Field

We experimentally explored the electrostatic demulsificationperformanceof water-in-heavy oil emulsion under a high-frequency/high-voltageAC electric field by considering some factors such as the shearingrate, water content, temperature, electric field strength, pulsatilefrequency, demulsifier types, and concentration. Relative viscosityreduction of heavy oil is used as the evaluation index for demulsificationperformance. The results indicated that the phase inversion pointof the heavy oil emulsion is between 40 and 50%. The demulsificationperformance can be improved by increasing the shearing rate if itis within the limited range. The optimum shearing rate in this experimentis around 100 s(-1) with the corresponding relativeviscosity reduction of 64.7%. There exist optimum electric field strength(2 kV/cm) and frequency (2 kHz) for the electrostatic demulsificationof heavy oil emulsion with water content 30% and temperature 60 & DEG;C.The relative viscosity reduction can be up to 67.5% under optimumelectric field parameters (2 kV/cm, 2 kHz). Six different types ofdemulsifiers used in this experiment all contribute to reducing theviscosity of the heavy oil emulsion. Among them, the type C demulsifiershows the best viscosity reduction effect. The relative viscosityreduction could be up to 76.39% with the combination effect of highfrequency/high voltage AC electric field. The viscosity reductioneffect is proportional to the demulsifier concentration. These findingscan help to optimize operating parameters for the crude oil dehydrationdevices to achieve best separation performance in heavy oil fields.