Application of the flux number approach for the simulation of granulation processes by use of flowsheeting tools

The present work describes the study of a continuous fluidized bed granulation process involving a solution spray as binder. The study entails the employment of a flux number as an extension to an existing flowsheet model (SolidSim). The agglomeration kernel used here is based on the Equi-Kinetic Energy principle and has been derived and proven for fluidized bed granulation processes using reactive and melt binders, but not for solution binders. This kernel has been correlated in the past to the flux number, which contains the main characteristics of the fluidized solids and the spray-on, such as the binder flux, the particle density and the fluidization gas velocity, in combination with population balances. This correlation was derived for a few liquid/solids systems only, notably small scale batch processes with melt binders, and a first attempt to the generalization of this correlation is shown here by its application to a completely different system, notably a continuous large pilot using a solution binder. The validated SolidSim flowsheet is useful for parameter variations and sensitivity analyses, showing a strong effect of the flux number exponent and the cut size of the screen on the product size distribution and recycle rate. Such quantitative relations between process conditions and product quality allow for significant savings in cost and time for process and product development and optimization.

► Growth rate kernels of continuous fluidised bed granulators can be predicted.
► Growth kinetics of melt binder systems are similar to solution systems.
► SolidSim has an improved and proven granulator model.
► Flowsheet simulations provide major savings in time to market and development cost.