An Experimental Investigation into the Induced Air Floatation of Fine Oil in Water Emulsions

Abstract

Abstract The induced air flotation (IAF) of a highly stabilized oil in water (o/w) emulsion has been studied experimentally in a batch column 10 cm in diameter and 150 cm in height. The main variables investigated were initial oil concentration (50 - 600 mg/L), oil droplet size distribution of feed (1.0 - 30 um), type of surfactant, gas superficial velocity, volume of liquid feed, and type of air distributor. Results were successfully analyzed in terms of a first order kinetic rate model which yielded a removal rate constant (K1) that varied from 2.0 to 60.0 h-1. Corresponding total organic carbon (TOC) removal efficiencies went from 20 to 99.9 percent illustrating the wide performance range for the flotation cell. In addition, an important contribution of this work was the development and recommendation of a standard method to create and quantitatively characterize test emulsions for use in experimental flotation equipment. Emulsion stabilities were determined experimentally from a static test and quantified in terms of a stability rate constant. This constant was less than 0.001 h-1 for highly stable emulsions and greater than 0.20 h-1 for unstable emulsions. For the values of K1 between these two extremes, emulsions were only moderately stable.