Agitated Thin Film Evaporators
Agitated thin film evaporators are used to concentrate liquid solutions or slurries and recover the solvent in case the liquids contain solvents. Agitated thin film evaporator consists of a jacketed vertical shell having an agitator shaft mounted with multiple blades on it. The clearance between the shell and blades are very low. Either steam or hot oil is passed through the jacket of the shell thereby heating the internal surface of the shell to required temperature. The liquid feed is introduced at the top and spread across the shell internal by the rotating distributor. The agitator blades while rotating spread the liquid on the heated shell surface causing the evaporation of the solvent or water and the concentrated product is discharged at the bottom. If the feed contains solvent the evaporator is operated under vacuum and the vaporised solvent is passed through a condenser to recover the solvent.
The agitated thin film evaporators are also used as short path distillation units (SPDU) by configuring an internal condenser which is mounted in the main shell. The high boilers and low boilers are separated in a SPDU.