Hydrodynamics of Fluidized Bed Reactors for Wastewater Treatment

Abstract : Mints' model adequately describes ideal static (nonvariable input parameters) liquid-solid fluidization. This model has a good theoretical basis and describes bed expansion relationships for a wide range of experimental data. This model has been verified for materials with low densities relative to the fluidizing liquid. The lower limit for the validity of Mints' model occurs at a Reynolds number, re, of approximately 1. It is suggested that below this value the state of fluidization does not exist, however, the regime of flow may correspond to an expanded bed. Deviations from the idealized model occur at low and high Reynolds numbers. These deviations correspond to unstable flow regimes, exhibited in the form of channeling and boiling. The loss of stability at high Reynolds numbers is due to the inherent instability of the layered structure of liquid-solid fluidized beds.