Mathematical Modelling of Granulation Processes

This thesis studies wet granulation on three
different levels. First, micro-level investigations
of liquid bridges between two and three particles are
performed. For the two-particle case, the fluid
profile of static (stationary) and dynamic (moving)
liquid bridges are investigated. Static liquid
bridges between three equally sized primary particles
are then studied; the symmetry of the problem is used
to obtain a numerical solution to the Young-Laplace
equation. Secondly, a model to estimate the
stickiness (fractional wet surface area) of
agglomerates is proposed. The model includes
parameters to control the inter-particle separation
distance and the fluid saturation state.
Computational geometry is used to obtain results
which relate the number of particles and the volume
of binder fluid to the stickiness of the
agglomerates. Finally, a population balance model for
wet granulation is developed by extending an earlier
model to incorporate the effects of binder fluid. The
model is solved numerically for a range of
coalescence kernels and results are presented which
show the effect of binder volume and the drying rate.