Hydrodynamics of two- and three-phase systems in an agitated vessel with two agitators

Abstract

The effect of the agitators configuration, the agitator speed, the volumetric gas flow rate, the sucrose concentration in aqueous solution, and the yeast suspension concentration on the hydrodynamics of two- or three-phase systems in an agitated vessel with two agitators has been presented in this paper. The gas hold-up and the average residence time of the bubbles were measured in agitated vessel with a liquid height of H = 2D and the internal diameter of D = 0.288 m. The study was carried out for gas-liquid and biophase-gas-liquid systems, where the gas phase was air, the liquid phase was distilled water or an aqueous solution of sucrose (c = 2.5% mass., 5% mass.), and the biophase was a suspension of Saccharomyces cerevisiae yeast (ys = 1% mass.). The research results were analysed taking into account the influence of the type of the upper or lower agitator, agitator speed, gas flow rate, and type of liquid in the system on the gas hold-up and the average residence time of the gas bubbles. The experimental results were mathematically described.

Keywords

• agitated vessel
• gas hold-up
• residence time of gas bubbles
• gas-liquid or biophase-gas-liquid