How does a fluid bed dryer work?
Fluid bed dryers, or continuous fluid-bed systems, are machines in which a continuous flow of “wet” powder, granular or flaked material is conveyed over a perforated bed. Hot air for drying is blown through the holes of a perforated plate. The wet solids are lifted from the bottom, causing the solids to behave as a fluid. The air velocity is adjusted to keep the moving layer of material fluidized.
Conveying of the product is achieved by means of a low-frequency, high amplitude shaker mechanism. The “Shaking” motion plug flow of the Tema fluid bed, allows first-in, first-out drying of products and well-mixed fluidization, which covers the entire spectrum and enables fluid bed dryers to accurately control the spread of residence time.
Fluid bed types
A fluid bed is an effective unit to thermally treat powders, crystalline products, pelletized or extruded materials. High heat and mass transfer are obtained as a result of the intimate contact between fluidizing air and product.
Units for continuous operation and suitable for sticky materials with a wide particle size distribution. The shaking motion improves the fluidization and transport of any material within the fluid bed. Drying gas temperature up to 750 °C and product temperatures up to 400 °C are achieved.
Units in continuous and batch type for more uniform materials that do not tend to agglomerate. It is possible to install submerged heat exchangers in a deep static bed. With submerged heat exchangers energy input is both from the fluidizing air as well as from the heat exchangers reducing the size of the equipment and limiting the exhaust air volume.