Two-phase mixing processes

The agitated tank is still the most widely used device for mixing immiscible phases. Industrial applications are highly diversified, covering all production sectors, and above all a range of plant sizes from a few liters to 1 or 2 thousand cubic meters.

Nevertheless, the basic principles, the phenomena that control the operation, are the same whether you work in the food or chemical sectors, in pharmaceuticals and cosmetics or paints...

What multiphase systems have in common is the complex role of agitation. In the case of two-phase systems where at least one phase is liquid, the second phase is dispersed in this liquid, generally in the form of bubbles, drops or particles. In simple, single-phase systems, the agitator(s) is (are) traditionally used to impart good homogeneity to the system, if possible quickly and at low energy cost. In two-phase systems, the agitator will also control certain characteristics of the second phase, in particular the circulations to which it will be subjected, or even the properties of the dispersion (size, distribution, etc.).

In these operations, the aim is either to achieve a final physical state of the system, or to improve its material transfer performance, with or without a chemical reaction. In each case, the user needs to define his priorities carefully, as it is not possible to define a system that is optimal from all points of view (speed of dispersion, energy cost, degree of homogeneity, transfer performance, etc.). In all cases, the choice of agitator models and their installation in the tank remain a major factor in the success of the process. It's only after this initial stage that it's possible to work on the operating parameters.