Gas-liquid mass transfer in an airlift reactor - analytical solution and experimental confirmation

Gas-liquid mass transfer behavior in an external loop airlift reactor is in vestigated. The riser and the downcomer of 6 m height have a diameter of 0. 15 and 0.08 m, respectively. The classical 'gassing out' dynamic method is used to obtain the evolution with time of dissolved oxygen concentration pr ofiles. An analytical description of the concentration profiles with time f ollowing the switch in the inlet gas concentration is presented and allows the evaluation of the gas-liquid mass transfer coefficient for the differen t gas velocities used. The comparison between the values of k(L)a determine d from this simplified model and those obtained in the same reactor from a more complete and sophisticated model shows a good agreement. (C) 2001 Else vier Science B.V. All rights reserved.