Computational Fluid Dynamics (CFD) modelling of the effect of distributor plate geometry in the bubbling fluidized bed reactor

Abstract

Air distribution is the primary factor that influences the performance of fluidized beds. To understand the hydrodynamics and operation of a fluidized bed, an assessment of the airflow and its distribution is essential. The design and operation of the fluidized bed are complex therefore numerical models have been proposed to predict the behaviour of fluidized beds. Although fluidisation has been studied fundamentally, systematic investigation of air maldistribution due to fluidised bed reactor design and geometry has not been characterised. The effect of four distributor plates (Plate A, B, C and D with 8.67%, 6.12%,4,2% and 2.4% open area, respectively) and the two fluidised bed reactors (straight inlet and bend inlet reactors) on the fluidisation hydrodynamics have been investigated. OpenFOAM™ v1712 was used to develop a computational fluid dynamic (CFD11CFD- computational Fluid dynamics) model to predict the behaviour of a bubbling fluidised bed. The determination of these characteristics will allow for an improved CFD model and optimisation of an industrial fluidised bed granulator. The model was validated with experimental data. Plate pressure drops of 76 Pa,121 Pa,296 Pa and 886 Pa were achieved with plates A, B, C and D respectively. High bed pressure drops were observed for plate It was therefore concluded that the pitch and open area percentage of the distributor has an effect on both the plate and bed pressure drop. Particles with 1.3 mm diameter fluidised quicker with minimum fluidisation velocity range between 0.3 and 0.8 m/s. There was an agreement between the model and experiments for plate and bed pressure drop and bed expansion. Air maldistribution was observed for bend inlet reactor.