A mechanistic model for breakage in population balances of granulation: Theoretical kernel development and experimental validation

In this study, a dynamic model is presented for the granulation process, employing a three-dimensional population balance framework. The major focus of this work is the theoretical development and experimental validation of a novel mechanistic breakage kernel that is incorporated within the population balance equation. Qualitative validation of breakage kernel/model was first performed and trends of lumped properties (i.e., total particles, average size, binder content and porosity) and distributed properties (i.e., granule size and fractional binder content) show good agreement with the expected phenomenological behaviour. Successful high-shear mixer granulation experiments using glass-ballotini as the primary powder and poly-vinyl alcohol in water (PVOH-H₂O) as the liquid binder were then carried out to mimic predominantly breakage-only behaviour whereby the rate of breakage was greater than the rates of nucleation and aggregation. Good agreement between experimental and simulation results were obtained for the granule size distribution under different operating conditions. In addition, accurate model predictions were obtained for the evolution of the lumped properties.