Hydrodynamics of Foaming Systems in Packed Towers

Foaming can be a serious problem in the process industry. For packed columns foaming is often reported for treatments of sour gases with alkaline solutions (e.g. amine scrubbing), but also for distillation and extractive distillation. Existing hydrodynamic prediction methods for pressure drop and flood points, but also for mass transfer efficiencies, do not consider foaminess. To build an experimental data base for modifications of the above mentioned models, this work systematically conducts experimental investigations on the influence of foaminess, geometry and flow conditions on the hydrodynamic behavior in packed towers. The aim of this study is to provide a database for the correlation of the foaminess of a solution determined in a test cell to its hydrodynamic behavior in the packed column with different geometries to enhance the predictivity of hydrodynamic and mass-transfer models. The experimental results show that existing empirical system factors developed for tray columns fail to predict the decreased loading capacity of the packings for the model solution. Whereas in non-foaming solutions flooding is especially sensitive to the gas load, for foaming solutions the capacity is strongly decreased also at high liquid loads. The influence of the geometry of the packing on the generation of foam is substantial. The contribution shows novel experimental results of foaming solutions in packed towers. These include the substantially by foaminess altered loading diagrams and different phenomena in the column. In addition different column internals are compared and design suggestions are given.