Fluidized bed drying
Fluidized bed drying / microencapsulation
Besides the lyophilization the fluidized bed process is also suited for the conservation of lactic acid bacteria. In the fluidized bed process first at all a carrier material is needed as a basis for the substrate that should be dried. This carrier material is held up in the air to enable the application of the substrate via a spray nozzle. Compared to spray drying the temperatures are lower. This is advantageous as the lactic acid bacteria are not damaged by thermic effects. In contrast to the lyophilization the fluidized bed drying is a short drying process and therefore it is interesting for the conservation of bacteria.
Application of bacteria and coating
The probiotic lactic acid bacteria are sprayed onto the dispersed carrier material in form of fine droplets. The contained water is deprived by the dry air that flows bottom-up through the fluidized bed. In the same time the stream of air is responsible for the fluidization of particles. Afterwards a protective coating is applied in the same matter onto the carrier that is coated with bacteria. It is a batch-prozess, meaning a defined amount of carrier is prepared in the vessel and coated with the respective amounts of bacteria suspension and protective coating. Afterwards the batch is harvested out of the fluidezed bed reactor. For 300 kg end product approximately 250 kg carrier is needed.
Facts - Coating
- Top-Spraying and Bottom-Spraying possible
- Performance of flexible-tube-pumps: 20 – 100 l/h
- Nozzels: 2 substances nozzels, compressed air used as nebulization air (6 bar)
Sieving and Filling
The product harvested from the fluidized bed drying contains dust and particles that stick together. These fractions are removed in the associated sieving. After sieving the product is filled into bags
Facts – Sieving
- Tumbler screening maschine
- Sieves are adjustable
- Performance: ~ 300 kg/h
|Pilot plant||2 kg/batch|