Particle Residence Times in Fluidized Bed Granulation Equipments

Abstract

Various types of fluidized bed equipments used in granulation were experimentally investigated in order to gain a more detailed insight in particle recirculation behavior and particle residence times in the two considered compartments, namely the spray compartment and the drying compartment. The investigated fluidized bed technologies comprise a top-spray process, a spout fluidized bed without and with internal riser, and a spouted bed. The measurements were conducted by using image analysis techniques on an almost 2D particle flow. From the results, conclusions about particle wetting and drying can be extracted, subject to fluidization velocity, nozzle mass flow rate, and facility/riser construction.

Influence of zone formation on stability of continuous fluidized bed layering granulation with external product classification

“…However, recent experimental investigations have shown that a significant change in the shape of the particle size distribution can actually occur, and the particles do not grow uniformly (Börner, Peglow, & Tsotsas, 2011;Grünewald, Westhoff, & Kind, 2010;Hoffmann, Peglow, & Tsotsas, 2011;Li, Kessel, Grünewald, & Kind, 2013;Zank, Kind, & Schlünder, 2001). This is attributed to only a portion of the particles being wetted by the injected solution owing to the position of the nozzle and the construction of the granulation chamber, and therefore the fluidized bed is separated into a spraying or granulation zone and a drying zone (Heine et al, 2013;Maronga & Wnukowski, 1997;Sherony, 1981;Wnukowski & Setterwall, 1989).…”

“…Characteristic values G Model for a top spray process and various bottom spray processes were given by Börner et al (2011) and Hampel et al (2013). Different definitions of ˛ have been provided.…”

Stochastic Modeling of Fluidized Bed Granulation: Influence of Droplet Pre‐Drying

“…The coefficients A = -6 · 10 -6 m s -1 and B = 3.3 · 10 -3 m s were determined by investigation of a 2D fluid bed with c-Al 2 O 3 particles, d p = 1 mm [23]. The Reynolds number Re is defined by superficial gas velocity, particle diameter and kinematic gas viscosity.…”

Dynamic Multi-Zone Population Balance Model of Particle Formulation in Fluidized Beds

“…The exchange rates between the drying zone and the spraying zone are given by the residence times of particles in the zones, 1 and , and can be related to the relative zone sizes 1 and [16,17]:…”