Fluid Bed Dryer

Fluidized bed drying is the optimal method for controlled, gentle and even drying of wet solids. The technology is also suitable for post-drying of spray granulated or extruded products with very low residual moisture.

Moist material is fed into a shaking perforated steel bed through which the drying air flows.  The air is of sufficient volume that it lifts, or ‘fluidizes’, the bed of material allowing intimate contact with each particle.  The shaking action of the bed assists in the transportation of the material over the length of the dryer.  Moisture is carried away by the air into a dust recovery system, whereby the hot air can be recycled in a closed loop back to the process.  The flow of air is controlled along the length of the dryer to maximise fluidization, enabling very wet and sticky materials to be handled.  As the material passes along the dryer it gradually loses moisture until the target dryness is achieved, at which point it passes into a cooling zone.  Here the hot air is replaced by cool ambient air, which reduces the product temperature to the desired figure.

Fluidized bed drying can be used in the entire powder processing industry. In the pharmaceutical industry, this innovative method has replaced the time-consuming tray drying long ago: The drying process with fluidized bed drying reduces the drying time in the drying oven by approximately twenty times. In addition, fluidized bed drying provides controlled and uniform drying conditions compared to the uneven drying in trays.


 Flow Diagram



Features :

  • Provides extended residence times
  • Provides intimate contact between drying/cooling gases and products
  • Multi zones, velocities, temperatures, drying & cooling
  • Can be designed for open circuit partial gas recycle
  • Plug flow or well mixed
  • Can be designed with  straight sides or with an expanded canopy
  • Flexibility of residence time and temperatures
  • Up to 90% of the thermal duty can be supplied/removed by installing contact heat exchange tubes within a deep fluidized bed

Advantages :

  • Ideal for removal of surface and bound moisture in powder, crystalline or granular materials
  • Good thermal efficiency
  • Can handle a wide range of materials, particle size distributions and material cohesiveness
  • Enables quick replacements, minimizing shutdown times and maintenance requirements
  • Enables energy savings and system integration
  • Plug flow is suitable to products that require longer residence time and a relatively tight moisture specification
  • Is suitable for use as an elutriator or avoid excessive carry-over
  • Enables high inlet temperatures for non-heat sensitive products which reduces the capital and running costs
  • Reduces airflow and plant size and improves cost, emissions and power consumption

Applications :

  • Detergent Powder (as 2nd stage)
  • Agglomerated Powder
  • Pharmaceuticals Powders
  • Dextrose
  • Fruit Pellets
  • Milk Powder (as 2nd stage)
  • Cheese Powder
  • Salt (Nacl)