Development and validation of a batch fluidized bed dryer model for pharmaceutical particles

Batch fluidized bed drying is a common process for water removal in pharmaceutical particles. Multiple phenomenological models for this type of dryer are proposed in the literature, with many of them relying on the two-phase theory. This article elaborates on a two-phase model and extends it for the pharmaceutical case by improving the particle, batch size and heat loss descriptions. An explicit methodology with low computational cost is also developed for solving the fluidized bed equations. Then, based on a grey-box modeling strategy, parameters with known value are fixed, while the unknown parameters are calibrated with experimental data collected on a pilot scale fluidized bed dryer. Lastly, the model is dynamically validated on distinct experimentation datasets. It is shown that the simulations are able to reproduce the pilot data trends, but there is still room for improvements in the heat loss representation.