Radioactive particle tracking in a lab-scale conical fluidized bed dryer containing pharmaceutical granule

Radioactive particle tracking (RPT) has been used to study the motion of the particulate phase in a bench-scale conical fluidized bed containing dried pharmaceutical granule. RPT revealed that there is a distinct circulation pattern of the granule with particles moving upwards at high velocities near the centre of the bed and falling slowly near the walls. There was also a localized region near the centre of the bed where particles moved downward rapidly. The particle size distribution (PSD) of the granule had an appreciable impact on particle motion with a wide PSD leading to larger fluctuations in particle velocity as well as poorer granule mixing.