A population balance model for high shear granulation

Abstract

In a previous paper, Hoornaert et al. (Powder Technol. 96 (1998); 116À128) presented data from granulation experiments performed in a 50 L Lo¨dige high shear mixer. In this study that same data was simulated with a population balance model. Based on an analysis of the experimental data, the granulation process was divided into three separate stages: nucleation, induction, and coalescence growth. These three stages were then simulated separately, with promising results. It is possible to derive a kernel that fit both the induction and the coalescence growth stage. Modeling the nucleation stage proved to be more challenging due to the complex mechanism of nucleus formation. From this work some recommendations are made for the improvement of this type of model.

Modeling of aggregation kernel using Monte Carlo simulations of spray fluidized bed agglomeration

“…The size‐dependent part of the aggregation kernel , on the other hand, reflects the influence of the flow field on the probability of collision between particles of different sizes. Many structures for the aggregation kernel have been presented in literature based on empirical, semiempirical, and physical approaches, but a comprehensive model capable of reflecting the effect of process conditions on aggregation behavior under rather general conditions is not yet available. Furthermore, the aggregation efficiency is often found to be strongly time dependent when extracted from experimental data.…”

An energy-based population-balance approach to model granule growth and breakage in high-shear wet granulation processes

“…More recently, the "population balance" approach has gained increasing popularity for modeling HSG processes [9][10][11][12][13][14][15][16] in which the total powder mass is distributed among various discrete granule sizes according to predetermined rates of granule growth and breakage.. However, the population balance approach, by itself, lacks the tools to independently predict such kinetics of granule growth and breakage and usually relies on the rate constants obtained from empirical data.…”

“…Separate rate constants for such individual processes as wetting, nucleation, growth, consolidation, and breakage 4 are sometimes used to improve the overall match between the predicted and observed results. 17 According to Wauters et al, 10 promising results are obtained for granule size predictions in the coalescence and granule growth phases; however, improvements in the area of granule nucleation are necessary. Also, according to Litster and Ennis, 18 there is limited quantitative information in the literature about the effect of granule breakage on granulation.…”