Effect of electrical field on demulsification of water in oil emulsion in emulsion liquid membrane process

Abstract

Emulsion liquid membrane (ELM) is one of the processes widely used in industrial separation process. The advantage of ELM processes with physical demulsification is recyclable liquid membrane without any chemical contamination. For recovery purpose the emulsion must be demulsified and the liquid membrane can be recycled. In this study, electrical field will be used as the method for demulsification of water in oil (W/O) emulsion in liquid membrane process. Demulsification process is operated using batch high voltage demulsifier systems. The emulsion is demulsified until organic and aqueous phases were clearly separated. The study involved the effect of electrical field on demulsification of water in oil emulsion. The influence of various values of frequency and voltage were studied using alternate current (AC) high voltage demulsifier with insulated electrode. The emulsion consists of kerosene as organic phase, sulfuric acid as internal phase and SPAN 80 as a surfactant. The effect of emulsion preparation such as homogenizer speed, internal phase concentration and surfactant concentrations on the stability of water-in-oil emulsion were also investigated. The results show that demulsification rate increases as the frequency and the electrical voltage increases. Under an electrical field the attractive forces between the water droplets increase by raising the applied electrical field strength. Thus, the acceleration of coalescence process increases. The study also found that, the time required for the emulsion to separate and coalescence under electrical field increased when the stability of emulsion increased.