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Item type:Publication, Access status: without files , Optimization of aqueous microgrinding processes for fibrous plant materialsFibrous plant-based materials are characterized by inhomogeneous structure and composition, which further evolve during wet grinding processes and affect the surface functionality of micronized particles. Therefore, the performance of aqueous microgrinding operations in stirred media mills can be optimized by investigating the interaction between process conditions and material properties of heterogeneous fibrous plant materials. In this experimental study it is shown how particle size reduction, tendency of re-agglomeration and stability of the suspension of micronized particles are driven by the specific energy input, residence time, temperature and presence of surfactants during the milling process. A structured experimental approach is described to optimize the achievable particle size reduction, expressed by the top cut diameter d90,3. It was found that the applied wet milling process determines the stability of particle suspensions throughout further downstream processing, making the grinding process the core unit operation with respect to the performance and formulation of food products containing micronized particles.Publicationtype: Journal Article131 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Product design based on discrete particle modeling of a fluidized bed granulatorFluidized bed agglomeration is a process commonly used to construct powdered food or pharmaceutical products to improve their instant properties. This works analyzes the influence of a wide range of operating parameters (i.e., fluidization air flow rate, temperature, and liquid injection rate) on growth rate, process stability, and product particle structure. Different granulator configurations (i.e., top spray, Wurster coater, spouted bed) are compared using identical process parameters. The impacts of both process variables and granulator geometry on the fluidization regime, the particle and collision dynamics, and the resulting product structure and corresponding properties are studied in detailed simulations using a discrete particle model (DPM) and lab-scale agglomeration experiments with amorphous dextrose syrup (DE21). The combination of numerical and experimental results allows to correlate the kinetics of micro-scale particle interactions and the final product properties (i.e., agglomerate structure and strength). In conclusion, detailed DPM simulations are proven as a valuable tool for knowledge-based product design. © 2013 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences.Publicationtype: Journal Article22 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Modeling of the spray zone for particle wetting in a fluidized bed(Wiley-VCH, 2013-01-29); ; ; ; In a spray agglomeration process the particle wetting influences the agglomerate growth and particle dynamics in the granulator. The mass of binder liquid that is deposited on single particles affects the amount of energy dissipation during particle contacts. For the agglomeration of colliding particles the whole impact energy has to be dissipated due to viscous and capillary adhesion forces in the liquid film and plastic deformation of the material. Therefore, a detailed knowledge of the particle wetting is necessary to model the agglomeration process. This contribution uses a coupled DEM-CFD approach to describe the spray zone of a two-fluid nozzle in a fluidized bed agglomerator. Droplets modeled as discrete elements showed the formation of a spray zone with a conical shape. Simulations of the spray zone and the wetting of single particles are in good agreement with experimental results. A coupled DEM-CFD approach is used to describe the spray generation of a two-fluid nozzle and the wetting of single particles. Valuable information to describe particle collisions of wetted particles is generated that are necessary to simulate fluidized bed processes, i.e. agglomeration and granulation.Publicationtype: Journal Article94