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. On a eu recours au suivi de particules radioactives (RPT) pour etudier le deplacement de la phase particulaire dans un lit fluidise conique a l'echelle de laboratoire garni de granules pharmaceutiques seches. La technique RPT revele l'existence d'un profil de circulation distinct de celui des granules, les particules se deplacant vers le haut a des vitesses elevees pres du centre du lit et retombant lentement pres des parois. Il existe egalement une region localisee pres du centre du lit ou les particules se deplacent vers le bas rapidement. La distribution de tailles des particules (PSD) des granules a un impact appreciable sur le deplacement des particules, une large PSD menant a de plus grandes fluctuations de vitesse des particules et a un plus faible melange des granules.