Modeling of elutriation phenomenon in fluidized beds

Elutriation occurs extensively in fluidized processes due to input of a wide range of particles or formation of fines by way of attrition. The entrained solids must be recovered or removed from the gas because of economic or environmental reasons. Thus the total quantities entrained and the concentration of solids in the gas stream must be known in order to design the solids removal systems. In the current research, the elutriation phenomenon is simulated using a multi-fluid finite-volume code. Numerical simulations are used to predict elutriation behavior for two types of solid particles with different diameters and densities fluidized by air in a laboratory-scale bed. The superficial gas velocity is chosen between the terminal velocities of the two solids. The total solids entrained for varying initial mass fractions of fines in the bed are computed and compared with experiments. The elutriation rate constants obtained from simulations are compared with the empirical formulations available in the literature. The concentration of solids distribution in the freeboard along the bed height is also presented.