Compartmental approach for modelling twin-screw granulation using population balances

In this study, a compartmental population balance model (CPBM) is developed as a predictive tool of particle size distribution (PSD) for wet granulation in co-rotating twin-screw granulator (TSG). This model is derived in terms of liquid to solid ratio (L/S) and screw speed representing the main process parameters of the TSG. The mathematical model accounts for aggregation and breakage of the particles occurring in five compartments of the TSG with inhomogeneous screw configurations (3 conveying zones and 2 kneading zones). Kapur's aggregation kernel is implemented in granulation and finite volume numerical method is adapted for solving the mathematical model. The results show a dramatic improvement in solution accuracy compared to the cell average numerical method. Moreover, Kriging interpolation is used to interpolate for new values of empirical parameters at different L/S and screw speeds. Finally, the CPBM model is calibrated and validated using the experimental data.