GAS-LIQUID CONTACTING WITH AXIAL-FLOW IMPELLERS

This paper focuses on the gas-dispersion characteristics of axial flow impellers. Various impellers are compared: an inclined blade impeller with flat blades, an A315 impeller and a Leeuwrik impeller. The goal is to gain insight in the gas-dispersion properties of such axial flow impellers. Therefore, the effects of impeller position and sparger ge ometry on flow pattern, power consumption and mass transfer are studie d in a vessel 0.444 m in diameter, using liquids of different viscosit y. The power consumption is strongly related to the different flow pat terns and different types of cavities. Under certain conditions time-d ependent, asymmetrical flow patterns can occur. The sparger type influ ences both the power needed to prevent flooding and the overall mass t ransfer coefficient k1a. The liquid viscosity does not affect the basi c hydrodynamic phenomena in the vessel for viscosities not exceeding 8 0 mPa s.