Abstract: Based on the self-designed continuous-flow electro-coalescence experimental apparatus with vertical annular flow channel and high-voltage/high frequency AC power supply, the effects of electric field parameters including voltage, frequency, pulse width ratio and residence time in electric field, on the electrostatic coalescing characteristics of dispersed water droplets in water-in-oil emulsions were studied systematically. The experimental results showed that residence time and voltage were the major factors affecting the coalescing process of water droplets. Frequency and pulse width ratio play an important role for power consumption rather than coalescing process. Therefore, optimum operation conditions for a certain emulsion should be selected by considering the coalescing process, treating efficiency and power consumption comprehensively.

Key words: water-in-oil emulsion, electrostatic demulsification, electric field parameter, vertical annular flow channel, flow condition