Meaning
Rapid phase change process involving the nearly instantaneous removal of a liquid carrier from a solid or concentrated solute. Often occurring in spray drying or vacuum environments, flash desolvation prevents the formation of large crystals by trapping the material in a disordered state. The speed of the event is the primary factor in determining the porosity of the resulting powder.
Solvent Removal
Heat transfer must be sufficient to drive the evaporation before the droplet hits a surface. During flash desolvation, the sudden loss of mass causes the remaining solid to harden into a shell. This mechanism is common in the production of pharmaceuticals where solubility and rapid dissolution are requirements.
Product Integrity
Particle size and density depend on the rate of heating. If flash desolvation happens too slowly, the particles may collapse or stick together. Controlling the vapor pressure in the chamber ensures that the solid structure remains intact.
Scaling Factor
Results from a small lab dryer rarely translate directly to a massive industrial tower. The air flow patterns in a large vessel change the time available for flash desolvation to complete. Production rates must be demonstrated under these full-scale conditions to avoid batch rejection.
A supplier’s forecast for yield is only as good as the data from the final production environment.
