CFD modelling of a countercurrent staged fluidised bed

The bed flow regimes and the hydrodynamics in a 2D countercurrent staged fluidised bed were simulated using Computation Fluid Dynamics (CFD). Based on the two-fluid theory, an Eulerian-Eulerian approach coupled with kinetic theory of granular flow (KTGF) for the solid phase was applied. The predictions were compared with the experimental results of Kuo and Cheng (2006). The calculated and experimental results both showed a non-growth flow regime, a dilute flow regime, an oscillating flow regime, a bubbling flow regime and a flooding flow regime on the perforated plate at different operating conditions. The values of the predicted pressure drop across the bed at steady state for the dilute flowing regime and the bubbling flowing regime agreed quantitatively well with the previous experimental results, although the time to reach the steady state was different. The calculated flow regime map as functions of the gas velocities and solids feeding rates agreed qualitatively with the experiments.