Dispersion (liquid-liquid) is defined as the production of a suspension of droplets of one liquid in another immiscible liquid. A dispersion is usually produced in order to enhance mass transfer of a component from one of the liquids to the other. Dispersions are produced by high shear mixing devices that impart a high level of turbulent energy to the system. This energy appears as turbulence which produces droplets of one of the liquids which is “dispersed” into the other. However, the energy level must be controlled so as not to produce a stable emulsion (see Emulsion). When the mass transfer is complete, the liquids will be expected to separate into two distinct phases which can be drawn off for further processing.

Vessel Design Considerations

These applications almost always require a vertical round vessel. Exceptions may be acceptable when the viscosity is relatively high, but these are unusual. The vessel should be selected so that the static height of the greater component is no higher than the vessel diameter. Angle offset mounting can be used, but we normally expect to see baffles installed in the vessel.