Rotary Drum Dryers
The Rotary Drum Dryers are one type of industrial dryer employed to reduce or minimize the liquid moisture content of the material it is handling by bringing it into direct contact with a heated gas. The dryer is made up of a large, rotating cylindrical tube, usually supported by concrete columns or steel beams. The dryer slopes slightly so that the discharge end is lower than the material feed end in order to convey the material through the dryer under gravity. Material to be dried enters the dryer, and as the dryer rotates, the material is lifted up by a series of internal fins lining the inner wall of the dryer. When the material gets high enough to roll back off the fins, it falls back down to the bottom of the dryer, passing through the hot gas stream as it falls. This gas stream can either be moving toward the discharge end from the feed end (known as co-current flow), or toward the feed end from the discharge end (known as counter-current flow). The gas stream can be made up of a mixture of air and combustion gases from a burner, in which case the dryer is called a direct heated dryer. Based on the configuration, rotary drum dryers can be classified as co-current, counter current, direct fired and indirect fired.
Unique Features
- Efficient drying of materials with high moisture contents.
- Handles a wide size range of materials with extended residence times.
- Design permits highest possible drying temperatures.
- Drying, cooling or calcination.
- High thermal efficiency.
Specifications
- Available with applicator rollers which are effective for drying high viscosity liquids or pasty materials such as potato starches, gelatins, adhesives and synthetic resins.
- The applicator rollers produce a dry product sheet with uniform thickness, density, and minimum dusting.
- Standard drum sizes ranging from 50cm diameter to 80 cm, 2.0m to 5.0m long. Double drum dryers are the most versatile and widely applied type of drum dryer. These drum dryers are ideal for drying foods, chemicals and pharmaceutical products of varying densities and viscosity.
Application
Co-Current Applications
Wet feed in contact with the hottest drying gases supplied from an external source, where heat transfer is by convection.
- Suifilter cakes
- Minerals, fertiliser
- Beet pulp
- Floatation concentrates
- Coal/coke
- Clays, phosphates
- Animal feeds
- Sludges
- Germ, stillage