Spray Dryer Modeling in Theory and Practice

Abstract

This article considers the modeling of spray dryers at various levels and the selection of the most appropriate level of detail for practical situations. The following model levels are described: (1) Heat and mass balances; (2) Equilibrium based models; (3) Rate based models; (4) Computational fluid dynamic (CFD) models. The value of each is discussed in relation to some typical problem scenarios. These include preliminary process design; process improvement; and troubleshooting operational and product quality problems. One particular focus of this article is finding realistic models of the performance characteristics of spray dryers which can be included in process flow sheet simulations while not imposing excessive run times and complexity.

Keywords:

• Spray dryers
• Heat and mass balance
• Equilibrium model
• Rate-based model
• Computational fluid dynamics

Acknowledgment

The author acknowledges the advice of Dr. Ian Jones of ANSYS CFX on recent advances in computational fluid dynamics.