Fluid bed drying: so that particles dry quickly and gently
This is what happens during fluidized bed drying: moist particles are fluidized in the fluidized bed, heated in a controlled manner and dried. Water or organic solvents evaporate.
Today, fluid bed drying is used in all powder processing industries. In the pharmaceutical industry, the innovative process has long replaced the time-consuming process in tray dryers, drying ovens or vacuum dryers.
This is how the drying process in the fluid bed works:
Speed: The drying time is reduced by a factor of about twenty compared to drying ovens. Due to the intensive heat and moisture exchange of the fluidized product, drying in the fluidized bed system is particularly effective and time-saving.
Controlled and gentle: Due to the permanent fluidization in the conditioned process gas flow, uniform drying conditions prevail on the surface of the particles – in comparison to the tray dryer. Water or organic solvents evaporate in a controlled manner at the cooling limit temperature, which is well below the supply air temperature.
Fluid bed drying at Glatt: in thermodynamic equilibrium
What are your product quality requirements, how high should the residual moisture of the particles be? Good to know: Our technology is also suitable for post-drying spray granulated or extruded products with very low residual moisture.
Regardless of how the particles have been generated – in the fluid bed, in the compulsory mixer, in the batch or continuously – fluid bed drying depends on the right process parameters:
We select the supply air temperature precisely so that only as much moisture evaporates from the surface of the granules as is transported outwards through the capillaries from the inside of the granules.
If the supply air temperature is too high, a superficial crust may form, making it difficult or even impossible to remove moisture from deeper layers.
Fluidized bed drying in combination with other processes
We use the outstanding drying properties of the fluidized bed for a wide range of process variants such as spray granulation, spray agglomeration, film coating, layering or microencapsulation: the aim is not to dry to a defined residual value. It is much more a question of controlled moisture throughout the entire process. This determines which particle structures and sizes are created during agglomeration, or whether singular particles are homogeneously coated.
Spray drying and spray granulation: to dry your liquids into powders or dust-free and free-flowing granulates
Do you want to dry a liquid product, a solution, suspension or emulsion? In classic spray drying in the spray tower, all liquid droplets dry within a few seconds as they fall from top to bottom. This produces fine powders at high temperatures.
Spray granulation is a special type of spray drying
Spray granulation combines the drying of a liquid with build-up granulation. At moderate temperatures, this process enables a variety of different particle shapes and morphologies. Whether fine porous granules with excellent solubility or solid millimeter-sized pellets are required, spray granulation in the fluid bed is a drying process with many options.