CE07 - Chimie moléculaire

Digital twin contribution to better control the morphological properties of aggregates under hydrodynamic constraints – MORPHING

Image analysis of aggregates in concentrated suspension by digital twins

Digital twin contribution to better control the morphological properties of aggregates under hydrodynamic constraints

Objecvtives of the Project MORPHING

The MORPHING project is part of a perspective of developing generic tools aiming at allowing a fundamental advance in the understanding of aggregation phenomena in suspension. The aggregation of latex nanoparticles with a butadiene core in an industrial stirred reactor is a case study. The scientific questions concern the effect of physicochemical parameters and hydrodynamic constraints on the morphological properties of the aggregates.

A pilot unit allowing to reproduce the industrial process of latex coagulation/aggregation as well as a laboratory device allowing the study of the batch process were designed and tests were carried out according to a specific protocol similar to the industrial process to evaluate the effect of the physico-chemical and hydrodynamic conditions on the morphological properties of the aggregates formed in suspension. Optical visualization techniques are developed to characterize the morphology of the aggregates and the hydrodynamic constraints in the reactors. Stochastic geometry methods based on the simulation of the observed aggregates by their numerical twins are implemented in order to quantify the morphological properties of the aggregates and to follow their temporal dynamics under the effect of the imposed physicochemical and hydrodynamic conditions. This knowledge will then be integrated into a multidimensional population balance modeling of the aggregation process. Finally, the coupling of hydrodynamics and population balance models will be adapted to the simulation of industrial reactors.

Several results were obtained during the first phase of the project:
- Identification of the aggregation mechanisms of MBS latex in stirred reactor
- Determination of the effect of physico-chemical parameters (coagulant concentration, temperatures of the different steps of the process, solid concentration) on morphological parameters (size distribution, circularity distribution, fractal dimension, ...).
- Mapping of the hydrodynamics of the stirred reactor using a mobile «Retreat blade impeller« type
- GRAPE model (stochastic geometry) allowing to approximate the 3D properties of compact aggregates from 2D projection images with less than 5% error on average.

The image processing of aggregates obtained in concentrated suspensions constitutes a challenging scientific and technical barrier. Indeed, the development of in-situ visualization and image processing techniques based on the simulation of the aggregates observed by their digital twins, adapted to the study of concentrated systems, is completely new. This knowledge will then have to be integrated into a modelling of the aggregation process and adapted for the simulation of industrial reactors. In that framework, multidimensional modelling by population balance, coupled with Computational Fluid Dynamics, is another challenge, bringing innovative breakthroughs in the design of industrial aggregation reactors.

1. A. Hamieh, C. Coufort-Saudejaud, A. Couffin, A. Liné, C. Frances:Impact de la température sur la morphologie d’agrégats de nanoparticules de latex de type MBS lors d’un procédé d’agglomération en milieu liquide (SFGP 2022), Toulouse, France, 07-10/11/2022
2. C. Frances, A. Hamieh, C. Saudejaud, A. Liné : Analyse des propriétés morphologiques d’agrégats de latex générés en réacteur agité, 4èmes Journées Scientifiques du GDR MORPHEA, Nancy 5-6/10/2021
3. A. Hamieh, C. Saudejaud, A. Liné, C. Frances: Evolution d'agrégats de latex MBS au cours d'un procédé d'agglomération, 5èmes Journées Scientifiques du GDR MORPHEA, Toulouse 25/10/2022
4. L. Théodon, C. Saudejaud, J. Debayle : GRAPE : A simple stochastic 3D model for aggregates of particles with tunable 2D properties, 5èmes Journées Scientifiques du GDR MORPHEA, Toulouse 25/10/2022

The MORPHING project plans to develop generic tools enabling a fundamental step towards the understanding of suspended aggregation phenomena. Its purpose is to propose breakthrough solutions to improve aggregation processes and therefore better control the morphological properties of the formed solid. An industrial application is particularly targeted: the aggregation of budatiene core latex whose production is a real economic and societal challenge. This is carried out in a cascade of agitated reactors fed by a suspension of latex nanoparticles. The scientific questions focus on the effect of physico-chemical parameters and hydrodynamic conditions on the morphological properties of aggregates. The methodology proposed in the MORPHING project aims to identify under realistic conditions (dense suspensions in agitated reactors) the stresses on the aggregates and to identify specific hydrodynamic situations (shear stress of variable intensity, elongation stress over short to long periods) that can be reproduced and controlled in model flow cells. In parallel with the implementation of these model geometries, optical visualization techniques will be developed in order to be able to monitor in situ the dynamics of the morphology of the aggregates. The processing of images of aggregates obtained in concentrated suspensions is a major scientific and technical challenge. A specific stochastic geometry method will be developed based on the simulation of the aggregates observed by their digital twins, which will then be representative of the real binary images. This approach will allow quantifying the morphological properties of the aggregates and to monitor their temporal dynamics under the effect of the physico-chemical and hydrodynamic constraints imposed. This knowledge will then be integrated into a modelling of the aggregation process by multidimensional population balance. The coupling of hydrodynamics and population balance models will finally be adapted to the simulation of industrial reactors. The project is based on a multidisciplinary approach, bringing together researchers in particle process engineering, fluid mechanics, applied mathematics (stochastic geometry) and industrial R&D engineers with expertise in polymer chemistry (ARKEMA, leading player in the latex synthesis).

Project coordination

Christine FRANCES (LABORATOIRE DE GENIE CHIMIQUE)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

LGC LABORATOIRE DE GENIE CHIMIQUE
LGF LABORATOIRE GEORGES FRIEDEL
ARKEMA FRANCE / RECHERCHE
TBI Toulouse Biotechnology Institute

Help of the ANR 518,709 euros
Beginning and duration of the scientific project: December 2020 - 48 Months

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