Spray drying is the transformation of feed from a fluid state into a dried particulate form by spraying feed into a hot drying medium.
Spray drying system consists of four process stages.
- Atomization of feed into a spray.
- Spray - Air contact
- Drying of spray
- Separation of dried product from the air.
The feed is pumped from the product feed tank to the Atomizer system which is located within a ceiling air disperser through which drying air enters the drying chamber. The air is drawn from atmosphere by a supply air blower and passed through an indirect Hot Air Generator. As and when the drying air comes in contact with the spray, evaporation starts and dried powder particles falls to the base of the chamber. The exhaust air passed to the atmosphere via exhaust air blower and Wet scrubber.
Adequate instrumentation is given for temperature control, chamber pressure control, air damper systems for adjusting the air flows, speed controller for feed pump etc.