Fluid Bed Dryers

Fluid Bed Dryers

FBD refers to a Fluidized bed dryer that is commonly used in the pharmaceutical industry to reduce the moisture content of pharmaceutical granules. It is the best technique used by the manufacturer to produce a good quality product. However, with time, new advanced techniques are introduced to replace old like; in case of FBD, a new version has been introduced that is called FBP. FBD works on the fluidization principle. A high-pressure Hot air from the supply is passed through the perforated container containing wet granules. As the hot air passes through container granules start to suspend in the air to become dry (called a fluidized state), the process is called fluidization.

A fluidized bed dryer works by passing Hot air with high pressure through a perforated bed of moist solid particles. The hot air passes at a velocity greater than the settling velocity of the particles resulting, particles starting to suspend in the air. As the moist particle suspends in hot air, the moisture content of solid particles reduces to achieve the desired loss on drying (LOD). The drying vapors carry the vaporized liquid away from the moist solid particles. In some cases, the leaving gas is recycled to conserve energy.

Advantages of FBD

• If the gas-particle constant is excellent, it can lead to efficient heat and mass transfer rates, which results in faster removal of moisture.
• If part of the thermal energy for drying is supplied by the internal heat exchanger, high thermal efficiency is usually achieved.
• Lower initial and ongoing costs.
• Drying contact time is reduced.
• Stability and easy to control.