Author Description

Size-enlargement and structuration processes in fluidized beds such as granulation and agglomeration play an important role in the pharmaceutical and fine chemical industries as well as in food technology to improve the flowability and the instant properties of solid products. Dustfree and free-flowing particles can be produced in a process with favourable heat- and mass transfer conditions. Furthermore, this technology allows the formulation of particles with novel functionalities by applying coating layers or via the encapsulation of active ingredients. Several interdependent micro mechanisms including particle collisions, wetting, drying and phase transitions govern the process dynamics and complicate predictions on the effect of variable operating conditions on product properties such as structure, strength and re-dissolution behaviour. Profound knowledge on these mechanisms is needed to understand the influence of individual process parameters on the final product properties.A suitable approach to model the particle interactions in fluidized beds is the Discrete Element Method (DEM) coupled with Computational Fluid Dynamics (CFD). Information on gas and particle velocities, particle rotation and collision dynamics, which are very complicated to measure in fluidized beds, can be studied in detail with this technique.This thesis presents DEM-CFD simulation results for three different granulator configurations (top-spray, Wurster-coater, spouted bed) in comparison to experimental results, regarding the agglomeration of amorphous maltodextrin (DE 21). In simulation and experiment the identical geometry of the equipment was used. Mechanical material properties, such as the coefficient of restitution and the Young's modulus, which are required for the DEM model and which are frequently used as fitting parameters, were measured via static and dynamic deformation tests using maltodextrin agglomerates, beads and bars. The strength of the experimentally produced agglo