Column impedance and the hydrodynamic characterisation of pulsed plate columns

The concept of column impedance is introduced and the use of laboratory characterisation tests is described for evaluating the physical-property dependent terms in the holdup and droplet size equations which have been proposed earlier for pulsed plate columns. The use of these equations is illustrated with reference to the calculation of interfacial areas and the column diameter required for a given throughput. Current problems in the prediction of mass transfer rates are discussed in the context of interfacial (Marangoni) effects. (author)