Investigation of the hydrodynamics of packed-fluidized beds: Characterization of solids flux

This work investigates the impact on solid flux of applying Aluminum Silicate Balls (ASB) random packing in packed-fluidized beds. The interaction of different packing sizes, bed particle sizes and superficial gas velocity was studied. Experiments were conducted in a cylindrical cold-flow reactor with an inner diameter of 12 cm and a height of 1 m. The ASB packings were applied on a net grid in the middle of the reactor. Bed material was added from the top and temporarily formed a fluidized bed above the packed section. Bed particles then trickled downwards through the packed section during confined fluidization. The bed material was silica sand, with mean particle sizes of 119,181, and 303 μm. ASB packings of two sizes (12.7 and 6.3 mm) were evaluated. Air was used as fluidizing gas, applied at the superficial gas velocities of 0.1 m/s, 0.2 m/s and 0.3 m/s. The measured solid flux was 1.2–13.6 kg.m−2.s−1. Large particle size, large packing size and low superficial gas velocity resulted in high flux, and vice versa. It was concluded that ASB packings constitutes a significant hindrance for solids throughflow in packed-fluidized bed applications. However, it could be interesting for counter-current flow applications.