Development and validation of a discrete particle model of a spout-fluid bed granulator

Spout-fluid beds find a widespread application in the process industry for efficient contacting of large particles with a gas. Since the spout-fluid bed configuration allows for the introduction of a liquid, spout-fluid beds are used for both coating and granulation applications, for example in the fertilizer industry. In this application, the spout-fluid bed has the advantage of producing strong granules over a wide range of particle sizes. However, the particle size distribution obtained in spout-fluid beds can be relatively wide resulting in large recycling requirements. The objective of this thesis is to improve the control over the particle size distribution resulting from spout-fluid bed granulation by gaining insight into the underlying fundamental processes. As detailed experiments in operating granulators are virtually impossible, it was decided to adopt a modeling approach. Since the flow behavior inside the spout-fluid bed was considered to be most critical, the modeling efforts were focused on the hydrodynamics.