SPRAY DRYERS AND SPRAY DRYING TECHNOLOGY
What is a Spray Dryer?
A spray dryer, as the name implies, is a device for drying, utilizing a spray.
A spray dryer mixes a heated gas with an atomized (sprayed) liquid stream within a vessel
(drying chamber) to accomplish evaporation and produce a free
flowing dry powder with a controlled average particle size.
The unit operation of spray drying includes the following key components:
- A method for
solution or slurry
- An air/gas heater, or a
source of hot air such as a waste flue gas
- A gas/spray
with adequate residence time and droplet trajectory distance for achieving the
heat and mass transfer
- A means for
solids from the gas stream
- A fan to induce the required
air/gas through the spray drying system
The unique feature of a spray dryer is the surface area per unit weight
generated by atomization of the liquid feed. It is this fact that enables
a spray dryer to work. For example, feed atomized to 100 micron average
droplet size generates approximately 15,400 ft2/lb of surface area.
The same feed atomized to an average of 20 micron generates approximately 77,021
ft2/lb! This is equivalent to spreading one gallon of feed over 14
Additional Information About Spray Dryers
and Spray Drying Technology
Spray Drying |
Spray Dryer Atomization |
Spray Dryer Design |
Laboratory Spray Dryers