Modeling of multi-component granule formation in a wet granulation process

A methodology for in silico formation of realistic three-dimensional virtual granules consisting of multiple types of primary particles and a liquid binder has been developed. Populations of virtual granules with varying composition and binder content have been generated for the case of smooth, rough, hydrophilic and hydrophobic primary particles and their combinations. The equilibrium distribution of liquid binder within the wet granule microstructure was found in each case by the volume-of-fluid (VOF) method and the fraction of surface binder accessible during granule-particle collision was determined by a particle shooting method. The functional dependence of the accessible binder fraction on the volumetric composition of granules was thereby constructed and its sensitivity on the primary particle properties (shape and wettability) established. This functional dependence is an important input for a multi-variate population balance model of low-shear wet granulation.