Process Intensification of solvent extraction processes for biological products, production of biodiesel from raw feedstocks, and of phase separations is an area for the potential small-scale applications of DC electric fields to liquid-liquid contacting. Simulated design of possible configurations of electrically enhanced reactors would be important in this context. The aim of this work was to validate a novel finite element algorithm for the prediction of three-dimensional trajectories for electrically charged drops. Earlier work had shown accurate prediction for newtonian liquid-liquid system and for a range of different contactor geometries. The current work sought to extend this to non-newtonian liquids. The results of trajectory studies of electrically charged non-Newtonian liquid drops dispersed into a non-Newtonian, immiscible continuous phase in an electrically enhanced rectangular glass column are presented here. Only the electrohydrodynamics of the droplets are studied and other modes of transport process are not considered. In this study, the continuous phase was selected on the basis of low electrical conductivity values (< 10^-10 S/m), a non-Newtonian rheology and optical transparency. The liquids used as the continuous phase were mixtures of polyisobutylene in mineral oil. Dispersed phases having a range of rheological properties were also studied. These included newtonian aqueous solutions, non-newtonian aqueous solutions of carboxymethyl cellulose (CMC) and aqueous Blanose. The motion of the droplets in three-dimensional space was videoed using a Sony digital camera. Image analysis software Image J was used to digitize the videos and to determine the time dependent xyz trajectory, the velocity data for the droplets and the corresponding drop sizes. The discrete drop and electrostatic dispersion regimes were studied. Physical parameters included, interfacial tension, viscosity, the density of both phases, and electrical conductivity of the dispersed phases. These were measured to physically explain the droplet behavior and also to model the system accurately. The effects of the applied D C electric field, the polarity of the electric field, the nozzle dimensions, the dispersed phase flow rate, the nozzle insertion depth, and inter electrode distance upon the trajectories will be presented. Some interesting phenomena associated with falling drops were observed. These included droplet breakup, coalescence, and oscillations occurring at higher DC electric fields. These effects were simulated with the finite element modeling. An initial good match between the experimental and simulated data was observed.  

Keywords: electrically charged drops, D C electric field, non-newtonian, three dimensional trajectory, finite element analysis