ABSTRACT
In Section 3.3 it was demonstrated that the hydrodynamic condition of a pneumatic foam is crucially dependent on the characteristic bubble size, and that changes in the size with height in the column can change the hydrodynamic performance (see Section 3.7). In particular, the liquid flux through the column is determined by the characteristic bubble size at the top of the column, which, if a froth launder is adopted, is the bubble size upon the free surface. Thus it is important to consider what the mechanisms of bubble size change (i.e., “disproportionation”) are so that their impact on the hydrodynamic state can be understood. However, not only does the bubble size determine the hydrodynamics of foam fractionation column, but disproportionation of the foam as a function of height induces the mechanism of internal reflux, which will be discussed in Section 6.7.
