Principle: 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. Critical Process Parameter (CPP): Air Drying/Inlet temperature/Outlet Temperature/Bed Temperature/Drying Time/FBD bag Integrity (Before & After use)/FBD Bowl's Sieve Integrity (Before & After use).