Friday, 14 October 2011

Cronimo: Fluid Bed Dryer

Cronimo: Fluid Bed Dryer
In the pharmaceutical industry, fluid bed dryers are commonly used to dry batches of wet granules produced in a high shear mixer granulator.

Fluid bed dryers remove the moisture from the granules by suspending the granules in a heated air stream until dry. The movement of the granules in the heated air stream provides a relatively quick, efficient and uniform method of removing the liquids introduced in the previous wet mixing-granulation step. This process is called fluid bed drying (or fluidized bed drying) because the bed of granules suspended in the airflow is said to be fluidized.

Fluid bed dryers consist of a hollow vertical chamber where dry, heated air enters the bottom of the chamber and exhaust air exits through the top or rear of the chamber. There is a perforated diffuser plate at the bottom to diffuse the upward flowing air which helps create a stable and uniform fluidized bed. The diffuser plate can also support the bed when there is no airflow. The heated, dry air acts as both a fluidizing and drying medium for the solids.

Fluid bed drying is a batch process so the amount of material that can be dried depends on the size of the fluid bed dryer and nature of the material. Cronimo offers a line of fluid bed dryers with capacities ranging from 1 KG for R&D and formulation development up to production units with 350 kg capacities.

Fluid bed dryers used for removing solvents or non-water based binders must be designed in accordance with current explosion proof design standards as well as appropriate environmental regulations which can change depending on your location.

Spray Granulation:

Fluidized bed dryers can also be used for “spray granulation” which is a process where powders are agglomerated into granules while suspended in a fluidized bed hot air stream with the application of a liquid binding agent.