Convection dryer
The convection dryer is a device for drying solids in particle form. In it, heat is introduced into the dry material by a gas flow and the moisture contained in it is transported away.
A high level of heat and material transport is achieved through an often circulating flow of drying agent.
Drying phases:
- Heating (and simultaneous condensation during evaporative drying )
- First drying stage: The liquid on the particle surface evaporates / evaporates. At the same time, moisture is transported from the interior of the particles to the outside through large capillaries . As long as the surface remains moist, the drying speed remains constant.
- Second drying phase: Most of the water has been removed. The drying surface shifts into the interior of the particles. There is a sharp decrease in the drying speed.
- Third drying phase: The water bound in the product (also cell water) is removed. Very slow drying speed.
Examples would be:
- Chamber dryer,
- Belt dryer,
- Floor dryer,
- Drum dryer,
- Fluidized bed dryer,
- Spray dryer