Assessing particle segregation using near-infrared chemical imaging in twin screw granulation

In the present study the application of near-infrared chemical imaging (NIR-CI) for assessing particle segregation in granules from continuous twin screw granulation (TSG) granules, were the complex attributes of the machinery configuration in relation to particle segregation is not well understood was investigated. Experiments were performed along the compartmental length of the TSG barrel channel by varying the screw element type and liquid binder viscosity. Examination of the data showed a direct correlation between dispersion due to shear force and de-mixing of particles, which allowed for identification of fundamental granule segregation mechanisms affecting content uniformity in TSG. Particle segregation behavior was linked to dispersion due to shear force through a proposed regime mapping approach which links de-mixing potential to controlling granule formation mechanisms with a new dimensionless mixing number. This was carried out in order to provide a general guideline of how particles segregate along the length of the TSG barrel channel.