Combined population balance and thermodynamic modelling of the batch top-spray fluidised bed coating process. Part I—Model development and validation

A combined population balance and thermodynamic model was developed for the batch top-spray fluidised bed coating process. The model is based on the one-dimensional discretisation of the fluidised bed into different control volumes, in which the dynamic heat and mass balances for air, water vapour, core particles and coating material were established. The calculation method involves a Monte Carlo technique for the simulation of the particle exchange in combination with the first-order Euler’s method for solving the heat and mass balances. The model enables the prediction of both the dynamic coating mass distribution and the one-dimensional thermodynamic behaviour of the fluidised bed during batch operation. The simulation results were validated using the results from tests on a Glatt GPCG-1 fluidised bed unit.