Mathematical Modelling of Granulation Processes

This thesis studies wet granulation on threedifferent levels. First micro-level investigationsof liquid bridges between two and three particles areperformed. For the two-particle case the fluidprofile of static (stationary) and dynamic (moving)liquid bridges are investigated. Static liquidbridges between three equally sized primary particlesare then studied; the symmetry of the problem is usedto obtain a numerical solution to the Young-Laplaceequation. Secondly a model to estimate thestickiness (fractional wet surface area) ofagglomerates is proposed. The model includesparameters to control the inter-particle separationdistance and the fluid saturation state.Computational geometry is used to obtain resultswhich relate the number of particles and the volumeof binder fluid to the stickiness of theagglomerates. Finally a population balance model forwet granulation is developed by extending an earliermodel to incorporate the effects of binder fluid. Themodel is solved numerically for a range ofcoalescence kernels and results are presented whichshow the effect of binder volume and the drying rate.