Modeling of particle growth: Application to water treatment in a fluidized bed reactor

Crystallization process in a fluidized bed reactor to remove fluoride from industrial wastewaters has been studied as a suitable alternative to the chemical precipitation, which generates large amounts of a water rich sludge that must be disposed of with increasing costs. The major advantage of this technology is the decrease of sludge formation, the simplification of the materials recovery procedures and the reduction of solid wastes. Removal of fluoride by crystallization process has been carried out in a laboratory-scale fluidized bed reactor focused to the analysis of the influence of the supersaturation (S), the up-flow velocity (SV) and the amount and mean diameter of seed material (L0) on the process efficiency, which are related to the crystal growth. In the modeling, design and control of a fluidized bed reactor for water treatment it is necessary to study the particle growth kinetics. From the results obtained in this study, it has been proposed a growth model represented by the equation G = 2.96 × 10^−5L^(1.37) 0 SV^(0.5)S (m s^−1), which fits well the experimental data in the interval of variables studied.