Flow Dynamic Behavior of Fish Oil/Silver Nitrate Solution in Mini-Channel, Effect of Alkane Addition on Flow Pattern and Interfacial Tension

Abstract

The mini-fluidic contacting system is developed as process intensification platform as an attractive alternative for existing liquid-liquid extraction system for separation of Omega 3 PUFA from using Aqueous 50% Wt. Silver nitrate solution. To improve the performance of extraction in mini-fluidics, it is necessary to study the flow-dynamic behavior of fish oil silver nitrate system in the channel. Moreover, different flow patterns influence mass transfer and mixing which indirectly influence the separation efficiency of omega 3 PUFA from fish oil. Therefore, Different flow patterns were studied at Y-junction that connected to mini-channel and classified over a range of organic phase and aqueous flow rate. The flow is stratified at the “Y” Junction after phase inversion and also due to the reduction of interfacial tension between fish oil and silver nitrate solution. The addition of alkane’s solvents into the fish oil ethyl ester is attempted to change the flow pattern of fish oil silver nitrate system by elevation of interfacial tension. The formation mechanism of slug and stratified flow was studied by a competition between the gravity, inertia, viscous forces and the interfacial tension forces. The flow patterns maps is presented in terms of Ca, Re and We and identified the three regions namely gravity force dominant region, transition region and interfacial force dominant region. The flow patterns observed in real Fish Oil/AgNO₃ system was significantly different than previously reported for a synthetic DHA/AgNO₃ system. The addition of organic solvent into the fish oil ethyl ester increase the interfacial tension between fish oil and silver nitrate system, however, the increase was not sufficient to produce slug flow. This would suggest that practical processing of fish oils with AgNO₃ would require the handling of stratified flow within the processing units.