Population balance of droplet swarms in stirred extraction columns

The behaviour of droplet swarms in liquid-liquid dispersions, especially found in extraction columns, is analysed by means of a new fluorescence measurement technique, which represents an extension to the capillary suction method (Pilhofer and Miller, 1972). The measuring principle developed gains profit of the detectable emission light intensity of a fluorescent dye even in trace concentration. An addition of this nontransferring dye to the dispersed phase enables the in-situ determination of bivariate drop size / drop concentration distributions, which provides important information on droplet history for the evaluation of coalescence and break-up rates. Furthermore, the measuring method represents a new approach for the measurement of droplet size dependent residence times in extraction columns.