A theory for foam growth kinetics in the presence of antifoam emulsion

A theoretical model has been developed to predict the rate of foam production when gas is bubbled through an aqueous surfactant solution containing antifoam emulsion droplets. The calculation, using the theory of heterocoagulation kinetics, determines the probability of a gas bubble collecting an emulsion droplet during passage through the liquid. The principal assumption is that a bubble is short-lived if it collects an emulsion droplet with its hydrophobic particle(s), whereas bubbles free of hydrophobic particles are assumed to be infinitely stable. Specific rupture mechanisms and surfactant effects are not addressed by this treatment.The theory was used to predict the influence of gas flow rate, antifoam concentration and liquid volume on the rate of foam production. Reasonable agreement was obtained between experimental results and theoretical predictions.