DEM–CFD and PBM for dynamic process simulation of fluidized bed agglomeration
Dipl.-Ing. Gero Stöckl
A major problem in process engineering is scaling of processes that include particles. 10% of the global energy demand is wasted because industrial plant capacity is unused due to a lack of understanding of particle behavior. Many processes in chemical, food and pharmaceutical industry include fluidized beds. They offer high mass and heat transfer which makes them suitable for a wide range of applications. In fluidized beds occur multiple processes at the same time. This can involve processes such as agglomeration, granulation and coating. These processes impact the particle properties such as agglomerate size or porosity significantly. Due to that it is very important to have a deeper understanding of these processes and be able to predict product properties accurately. Modeling and predicting product properties based on design and operating conditions is difficult due to complex behavior of fluid and particles. This project focuses on developing an upscaling methodology for agglomeration in fluidized beds. This project is part of the Marie Skłodowska Curie training program TUSAIL. TUSAIL is an innovative training network funded by Horizon 2020 which comprises 16 academic and industrial partners in total, led by the University of Edinburgh. TUSAIL stands for “Training in Upscaling particle Systems: Advancing Industry across Length-scales”. Three approaches for upscaling:
(i) population balance modeling (PBM)
(ii) coarse-grained meso-particle methods
(iii) coupling between discrete and continuum methods are investigated.
These approaches form work packages of TUSAIL. A similar number of Early Stage Researchers (ESR) is assigned to each work package. An additional work package includes experiments, process validation and calibration. The work packages contain four main unit operations: (i) agglomeration, (ii) mixing, (iii) transport and discharge and (iv) milling.
This project uses both experimental and numerical approaches. Experiments are run on the Glatt GF 25 multi-chamber fluidized bed agglomerator. CFD-DEM simulations are performed to study fluid and particle behavior on the scale of single particles. The information on particle behavior provided by the CFD-DEM simulations is introduced into a large scale PBM model to predict agglomeration in fluidized beds at an industrial scale. The predictions are then validated by running experiments on a pilot-scale fluidized bed for different operating conditions and process configurations.
The aims of this project are:
(i) understanding the influence of process conditions on the product quality of granules
(ii) developing a dynamic flowsheet simulation to predict continuous fluidized bed agglomeration
(iii) being able to predict fluidization regimes and particle residence time distributions that are validated with a pilot scale fluidized bed.
Project funding and Start Date
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska Curie grant agreement No 955661.