A fluid bed dryer can handle up to 200 t/h and is used for drying of clay, sand, gravel, limestone, etc.
A continuous fluid-bed dryer/cooler is a machine in which a continuous flow of damp, granular material is conveyed over a perforated bed, through which air is blown to bring about fluidization. The material is dried in the first section of the machine and cooled in the second. Drying occurs because of the direct contact between the damp material and the hot air blown through it. The air velocity is adjusted to keep the moving layer of material fluidized. The same mechanism applies to the cooling part of the process, except that the air used is either ambient or conditioned (ie cooled). The drying and cooling sections of the machine form a single conveyor in which the hot and cool air flows are segregated. Conveying of the product is achieved either by means of a low-frequency, high amplitude shaker mechanism.
Fluid bed dryers are specially preferred in mineral drying in combination with after cooling and heat recovery, resulting in better end product quality and very low energy consumptions.