Mathematical Modeling of Aerosol Collection in Fluidized-Bed Filters

Abstract

In this work, an improved model for aerosol collection in fluidized-bed filters is developed. Based on the multistage three-phase concept of fluidization, a simple yet realistic model is presented. This model takes into account the major hydrodynamic aspects of fluidization as well as the various collection mechanisms. The model equations are solved analytically. Thus, compared with earlier studies, the present work offers the advantage of providing a physically consistent mathematical description that can be solved without the need to employ cumbersome numerical procedures. The model predictions agree reasonably well with the data for aerosol filtration in fluidized beds. The proposed analysis is then used to investigate the influence of various design and operating parameters on the bed collection efficiency. It is shown that for the systems examined in this work, fluidized filters are most efficient for aerosol particles smaller than 0.01 μm or larger than 100 μm. The overall collection efficiency can be significantly improved by reducing the gas velocity, increasing the collector diameter, or decreasing the bed aspect ratio.