Investigation on liquid-liquid dispersion in stirred tanks through experimental approach and computational fluid dynamic (CFD)

Abstract

Stirred tanks have a vital role in chemical engineering industries. Among the various applications of stirred tanks, mixing of two immiscible liquid phases is of interest in chemical processes. Mixing of two immiscible liquids in the stirred tank is an integral part of achieving a stable emulsion, which impacts the product quality. The design of the stirred tanks including but not limited to the geometry and dimensions of the vessel, the location, size, and the type of the impeller, fluid rheology, and the volume fraction of dispersed phase relies on comprehensive knowledge about the liquid-liquid mixing performance. One of the major factors affecting the stability of liquid-liquid dispersion is droplet size distribution (DSD) of dispersed phase. The study of DSD in liquid-liquid dispersions still relies on experimental data. The main objective of this study is to evaluate the effect of dispersed phase viscosity, volume fraction, and agitation speed on dilute liquid-liquid dispersions. Therefore, the liquid-liquid dispersion in stirred tank has been evaluated through electrical resistance tomography (ERT), focused beam reflectance measurement (FBRM), and computational fluid dynamics (CFD). ERT provides a non-intrusive online measurement to evaluate the mixing hydrodynamic of dispersion in the tank. FBRM technique is an online particle size measurement technique which evaluates the effect of mixing process on particle interactions and droplet size distribution. Using CFD coupled with population balance modeling (PBM) is the last step toward complete analysis of liquid-liquid dispersion process.