Hydrodynamics of slot-rectangular spouted beds: Process intensification

Abstract

Effect of bed geometry on the hydrodynamics of slot-rectangular spouted beds was studied by means of CFD-DEM simulations. Axial and lateral velocity distributions of particles as well as axial gas velocity distribution were used for validation of the simulation with experimental data. Static bed height and U0/Ums were constant in all simulations. Minimum spouting velocity as well as velocity, voidage and axial flux distributions of particles were determined and compared for six bed cone angles (20°–70°). An improved correlation for minimum spouting velocity was proposed which includes the effect of bed cone angle for the first time. Novel curved bed geometry, inspired from improvement of particle motion, was also proposed. Solids circulation rates for beds with different cone angles were evaluated by tracing sample particles in the bed. Axial distribution of lateral solids flux, which shows the insertion location of particles from annulus to spout, was determined for different cone angles. Combination of solids circulation rate (speed of circulation) and lateral flux (quality of circulation) was used to discuss about the effect of geometry on the circulation of particles. The best circulation behavior was observed in the curved bed.