Moisture powder/granule/pellet is dried into dried powder/granule/pellet

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              Originally fluid bed drying was used to replace the cumbersome and time consuming tray drying, which sped the process up by about 20 times as fast. Tray drying did not permis a uniform residual granule moisture, because this method presented an unpredictable combination of drying by conduction, convection and radiation. When fluid bed drying all particles are permanently suspended and mixed; allowing an efficient convection drying only. Nevertheless, the inlet air temperature should be chosen in order for drying tio be effected in a thermodynamic equilibrium, i.e. the hot air only removes as much moisture from the surface of the granules as can simultaneously travel outwards through the capillaries of the granules. Should the process air temperature be too high, the capillaries can easily close on the surface of the granules. From that moment onwards, convection drying will change to diffusion drying, resulting in extensively extended processing times.
These principles apply to any fluid bed drying, irrespectively, if drying high-shear granules or spray agglomerates, if batch or continuously processing. It has to however be considered that if effecting spray granulation, agglomeration or coating, one does not only remove a defined moisture content to a defined final residual value, but that drying also occurs during the spray process itself, i.e. that too high process air temperatures may also result in unsufficient liquid bridge, porous granule structures or frosty looking films. On the other hand, too low temperatures may result in lumps or a high percentage of agglomerates when filmcoating.
 
Fluid-bed drying process:
       Equipment model:
       FG FLUID-BED DRYER (drying granule/pellet/powder,batch drying process);
       GFG HIGH EFFICIENT FLUID-BED DRYER(only drying granule/pellet,batch drying process);
       XF FLUID-BED DRYER(drying powder/granule, continuous drying process);
       ZLG VIBRA FLUID-BED DRYER(drying easy broken granule/pellet/powder, continuous drying process).
 
Tray Dryer:
         Equipment model:
         CT,CT-C HEAT CYCLE OVEN(drying powder/granule/cake,batch drying process).