A thin film dryer (TFD) has two major assemblies – jacketed shell and rotor assembly having closely fitting hinged blades which rotates inside the shell. The feed enters the dryer tangentially and gets distributed equally along inside surface of shell in the form of thin film. The hinged rotor blades keep the film under intense agitation preventing any scale formation. Heating medium passing through the jacket evaporates volatile component in feed. The vapor generated flow counter currently to feed and leaves through vapor nozzle at top of dryer. The dry powder solids at bottom of dryer are collected in receiver. The feed material goes through different phase of slurry, paste, wet powder and finally comes out as a dry powde
Features Residence time of few seconds eliminates degradation of heat sensitive product. Drying in absence of air with indirect heating, hence effective for light and oxygen sensitive products. Complete solvent recovery is possible since no air is used for drying as in case of all direct (air) contact dryer. Operating pressure can be as low as 1 mbar Thermal efficiency of more than 85%, hence low operating lost compared to other dryer. Fine powder of uniform consistency eliminate use of pulverizer for grinding in downstream step. Amorphous powder can be obtained. Different rotor designs available for process & effluent drying. Applications Drying of bulk drugs, intermediates, dyes, pigments, organic & inorganic salts. Drying of effluent stream to get zero discharge. Recovery of solvents like DMF, DMSO & Glycerin from salt.
