On Mixing and Segregation in Binary Solid−Liquid Fluidized Beds

Abstract

A conceptual effective voidage model of a binary solid−liquid fluidized bed proposed by Bhattacharyya and Dutta (Ind. Eng. Chem. Res. 2002, 41, 5098) and successfully used to interpret the phase inversion behavior has been applied to the mixing and dispersion phenomena. A computational procedure for the determination of the axial concentration profiles of the two types of particles varying in size, density, or both has been developed. The values of the axial dispersion coefficients of the particles are evaluated simultaneously, satisfying the boundary conditions for the fluidized bed. Computed axial concentration profile and dispersion coefficients compared pretty well with available experimental data. Also, the experimental observations on the characteristics of liquid−solid fluidized beds as reported by different workers could be explained using the present model. A correlation for the dimensionless axial dispersion coefficients of the particle species was also developed. The most important feature of the model is that it relies upon the basic properties of the fluid and the solid particles and fitting of experimental axial concentration data are not required.