Dispersion Characteristics of Gas-Liquid Contactors Agitated by Single and Double-Stage Rushton Turbines

The study of the loading/complete dispersion transition is of great importance especially in processes with enhanced mixing requirements. In the present work, new data and correlations concerning the dispersion characteristics in gas-liquid contactors agitated by single and dual Rushton turbine systems are reported. The maximum amount of gas which can be completely dispersed, in the presence of gross, well defined recirculation patterns of gas at a given stirrer speed is predicted. Under these conditions, an increase of flow number with increasing Froude number could always be estimated. With decreasing impeller diameter, d, the same gas amount could be dispersed at higher stirrer speeds. At impeller spacing ΔH = 2 d, for d equal to 0.06 and 0.08 m, and ΔH = 1.54 d, for d = 0.10 m, the complete dispersion conditions of the dual impeller systems were slightly better than the corresponding conditions of the single impeller systems.