A Multi-Scale Hybrid CFD-DEM-PBM Description of a Fluid-Bed Granulation Process

• Main Authors: Maitraye Sen, Dana Barrasso, Ravendra Singh, Rohit Ramachandran
• Format: Article
• Language: English
• Published: MDPI AG 2014-01-01
• Series: Processes
• Subjects: computational fluid dynamics; discrete element model; population balance model; fluid bed granulation; multi-scale; simulation
• Online Access: http://www.mdpi.com/2227-9717/2/1/89

In this study, a hybrid multi-scale model has been developed for a continuous fluid bed wet granulation process by dynamically coupling computational fluid dynamics (CFD) with a discrete element model (DEM) and population balance model (PBM). In this process, the granules are formed by spraying the liquid binder on the fluidized powder bed. The fluid flow field has been solved implementing CFD principles and the behavior of the solid particles has been modeled using DEM techniques whereas the change in particle size has been quantified with the help of PBM. The liquid binder droplets have been modeled implicitly in DEM. A detailed understanding of the process aids in the development of better design, optimization and control strategies. The model predicts the evolution of important process variables (i.e., average particle diameter, particle size distribution (PSD) and particle liquid content) over time, which have qualitative similarity with experimentally observed trends. The advantage of incorporating the multi-scale approach is that the model can be used to study the distributions of collision frequencies, particle velocity and particle liquid content in different sections of the fluid bed granulator (FBG), in a more mechanistic manner.