Distribution of Solids in a Fluidized Bed Operated without a Gas Distributor

Abstract

Despite several advantages of a gas distributor, there are also some challenges in its application. Using a gas distributor increases the fluidizing gas compression cost. Due to deposition of fine particles and product of chemical corrosion, the gas flow area across a distributor may also be reduced. This paper investigates the distribution of solids in a fluidized bed operated without a gas distributor. The gas supply is through two opposite points on the column wall. In this bed configuration, the fluidized bed behaviour simulated using the CPFD (Computational Particle-Fluid dynamics) Barracuda code is compared with an equivalent system where a uniform gas distribution is assumed. For different powders with mean size 480 – 710 µm, the results show that the axial distribution of pressure fluctuation in both types of bed configurations are similar, particularly near the bottom of the bed. The relative solid fraction fluctuation is lower than 0.2 around the central axis and it spans over 21 – 83% and 41 – 65% of the bed diameter, respectively. These results therefore show that stable bubbling behaviour and good distribution of solids can also be achieved in a bed operated without any distributor.

Distribution of Solids in a Fluidized Bed Operated without a Gas Distributor