Spray dryers combine heated gas with the inflow of a container (drying chamber) that atomizes (sprays) the liquid to accomplish evaporation and produces a free-flowing dry powder with a controlled average particle size.
The unit operation of spray drying consists of the following major components:
1. Solution or slurry method for atomization.
2. Air/gas heater, or hot air source.
3. Gas/spray mixing chambers such as waste flue gas provide sufficient residence time and trajectory distance for droplets to achieve heat and mass transfer.
4. A unit for recovering solids from the gas stream.
5. A fan induces the required air/gas through the spray drying system.
A unique feature of the spray dryer is the surface area per unit weight created by the atomization of the liquid feed. It is this fact that makes the spray dryer work. For example, atomization of feed to an average droplet size of 100 microns yields a surface area of about 15400 ft2/lb. The same feed atomized with an average of 20 microns produces about 77021 sq. ft./lb! That's equivalent to spreading 1 gallon of feed over 14 football fields! Recent advances in the field of encapsulation have resulted in the production of nanocapsules and computational fluid dynamics (CFD) simulations through spray drying, ie nanospray machines.
https://www.stardrying.com/
