Electronic Thesis and Dissertation Repository

Degree

Master of Engineering Science

Program

Chemical and Biochemical Engineering

Supervisor

Dr. Hassan Gomaa

2nd Supervisor

Dr. Jesse Zhu

Joint Supervisor

Abstract

A novel emulsification technique has been developed for high throughput production of uniform emulsion droplets using high porosity oscillating stainless steel wire woven micro-screen. Different surfactants were investigated including dispersed/continuous bi-surfactant systems using Span80/SDS and Span80/Tween20. The effects of oscillation amplitude and frequency as well as the dispersed phase flux on emulsion average droplet size and uniformity were investigated. It was found that the droplet average size decreased with increasing the surface sheer stress. The emulsion droplet uniformity determined using the coefficient of variation (CV) changed with oscillations such that there was an optimal oscillating frequency for each amplitude where the CV was smallest. Furthermore, it was also found that both droplet size and uniformity were influenced by the content of surfactants and that the effect of process conditions was stronger for Span80/SDS system than for Span80/Tween20 system. The experimental data were fitted satisfactorily using shear stress function with R2 value of 0.97. Inserts were used to narrow the width of the continuous phase container and to build geometric channels. The flat surface inserts, the wavy surface inserts and the inserts with baffles have been studied. The results show that the droplet size decreased and the size distribution was widened. In the respect of monodispersion, the continuous phase channels with various geometries have detrimental influences in the oscillatory micro-screen emulsification system.


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