Meso-scale description of wet powders for industrial-scale modelling

Roxana Saghafian Larijani

Host Institutions

University of Twente [ 36 months ]

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Biography:

I am Roxana Saghafian Larijani, from Tehran, Iran. I did my B.Sc and M.Sc in chemical engineering (process design) at Amirkabir University of Technology(Tehran Polytechnic ) and the University of Tehran. In my B.Sc thesis I experimentally studied the performance of an impinging jet atomization photoreactor containing photo-catalyst particles. This made me curious about multi-phase granular systems, and in my M.Sc I focused on the CFD-DEM simulation of fluidized bed with non-spherical particles in the presence of an external electric field.

Continuing my research journey with granular systems, I am now investigating wet particle systems, particularly wet granulation process in which the liquid bridge force among particles will lead to the production of enlarged particles or agglomerates. As a chemical engineer, it has always been my passion to find out what can increase the efficiency of the processes and the quality of the product. In this project DEM modelling along with a particle upscaling approach(Coarse-graining) is being used, which will reduce the computational cost of the simulations, and allow us to predict the performance of industrial-scale granulators in different operational conditions.

Project Description

Methods exist to satisfactorily simulate fully saturated particle systems and systems in the pendular regime with independent liquid bridges. In the last case the liquid provides an additional force between pairs of (meso-)particles. The challenge lies in the intermediate liquid content range. This project aims to develop a meso-particle model to simulate wet systems for all degrees of saturation. The method will be applied to macro-scale processes e.g. agglomeration, granulation and mixing, where the size/type of particles evolves due to the fluid.

Specific objectives are:
  1. Establish and validate contact models between DEM (meso-)particles with varying amounts of liquid (0% to 100%), including liquid migration;
  2. Derive the relation between microstructure and liquid content to be included in the up-scaled meso-particles and wet-flow rheology;
  3. Apply the developed methodologies to selected wet industrial particle processes (granulation, mixing).
Expected Results:
  1. Micro-scale DEM simulation data and proposed contact laws in the pendular/funicular/capillary regimes;
  2. Meso-particle model for agglomeration, breakage, segregation and mixing
  3. Validation by application of models to granulation and mixing at Johnson Matthey and Nestlé.