2001 Volume 34 Issue 12 Pages 1532-1537
The solid-liquid mass transfer coefficients kL in gas-liquid-solid agitated vessels with new type impellers were measured to be compared with those in vessels with conventional impellers (e.g. propeller, paddle, Rushton turbine). kL for the new type impellers are larger than those for the conventional type impellers at a low impeller rotational speed and have the same value at the same total power consumption per unit volume. For the conventional impellers the rotational speed for the complete suspension NJS changes with the impeller height and the gas flow rate. In the case of the new type impellers for which the aeration assists the suspension of the particles, kL is correlated well with the sum of the power consumption per unit volume under aeration and the aeration power per unit volume. However, in the case of the Rushton turbine the aeration dose not affect the suspension, then kL under aeration is correlated just with the power consumption per unit volume. kLs for the conventional impellers are affected with the impeller position for the complete suspension.