BUBBLE-GROWTH IN SECONDARY FOAMS

When mechanical foambreakers are used in chemical engineering processe s to control an undesired primary foam, a secondary foam is often prod uced. Secondary foams consist of small bubbles, have a high liquid hol d-up, and cannot be condensed further by mechanical foambreakers. Seco ndary foams can be converted into liquid and gas in a coalescence colu mn by drainage, diffusion, and breakage of the lamellas. This paper pr esents a new model to determine the velocity of bubble growth and the time of coalescence of secondary foams. The experimental investigation s have been carried out with surfactants in aqueous solutions.