Flow patterns analysis of conventional versus eutectic liquid solvent in different circular small channel diameters

The move towards processes in small and micro devices has been increased recently due to the enhanced heat and mass rate of these devices. One particular area of application is liquid–liquid extraction. The efficiency of the solvent extraction as a result of two-phase flow in an intensified channel highly depends on the flow patterns. In this work, the hydrodynamics of conventional polyethylene glycol 200 (PEG200) and simulated diesel have been investigated intensively by varying several parameters such as junction shape and diameter, channel diameter, and channel saturation. To study the effect of solvent properties, experiments were carried out by changing the polyethylene glycol to a eutectic solvent (DES) through adding a specific amount of tetra butyl ammonium bromide (TBAB) to the PEG200. The main observed patterns were the drop, plug, various states of annular flow, and irregular flow. Those patterns were highly influenced by the channel diameter. Using DES as a liquid solvent resulted in the development of a different form of plug flow known as plug dispersed. The measured pressure drop was found to raise with rising solvent velocity, solvent viscosity, and decreasing channel diameter. This work gives a clear understanding about the behavior of different solvents to achieve efficient sulfur reduction from liquid fuel in a small scale.