The task of this work was the development of a method that enables the determination of drop size specific coalescence rates in extraction columns quantitatively. The experimental set-up used was a new developed fluorescence measurement technique that had been tested under laboratory conditions and was adapted to an extraction column in this work for the first time. This technique enables the simultaneous determination of drop size and drop concentration, where concentration in this context means the concentration of a fluorescent tracer in the drop. Compared with common methods used for the evaluation of coalescence rates, the measurement of not only drop size, but also drop concentration in a second dimension is an extension that gives important information of the droplet swarm behaviour that has not been available up to now. In the practical part of this work bivariate drop size/drop concentration distributions were measured at different heights of the column for processes with and without mass transfer at steady-state. Marking a 50%-fraction of the dispersed phase inlet stream with a fluorescent dye, conclusions could be drawn from such experimental data about the coalescence and break-up rates determining the process. The results give hints to the phenomenology of drop coalescence and drop break-up under mass transfer conditions.
|Effective start/end date||1/01/95 → 31/12/99|