Influence of the emulsion formulation in premix emulsification using packed beds

Premix emulsification was investigated using packed beds consisting of micron-sized glassbeads, a system that avoids fouling issues, unlike traditional premix membrane emulsification. The effects of emulsion formulation were investigated, most notably the viscosity and the surfactant. The dropletsize was reduced by increased shea rstress in the emulsion. This was stronger at low viscosity ratios than at high ratios. As expected the flux was proportional to the overall emulsion viscosity, and emulsions with small droplet size (Sauter mean droplet diameter o5 µm) could still be produced at up to 60% of dispersed phase provided that sufficient surfactant was available. More uniform emulsions(spanE0.75) were produced withTween-20(nonionic )and SDS(anionic) as surfactants than with CTAB (acationic surfactant), possibly due to acombination of a low equilibrium interfacia ltension and electrostatic attractions with the glass surface. Scaling relations were proposed taking into account all investigated product properties that can describe the dropletsize successfully.