Development of predictive models for flocculation processes (Application in papermaking ) Développement de modèles prédictifs pour les processus de floculation (Application à la fabrication du papier)

SEGHIR, SALEM (2024) Development of predictive models for flocculation processes (Application in papermaking ) Développement de modèles prédictifs pour les processus de floculation (Application à la fabrication du papier). Doctoral thesis, Faculté des Sciences et de la technologie.

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Abstract

In this study, we employ two distinct approaches within two-dimensional population balance modeling to elucidate the flocculation dynamics of PCC particles when treated with polyelectrolytes. In this analysis, the fixed pivot technique model is compared with the model initially described by Hounslow (1988) and later refined by Spicer and Pratsinis (1996b). Additionally, the median floc sizes measured using Light Diffraction Scattering (LDS) are compared with the predictions made by these models to evaluate their accuracy and applicability. To ascertain the fidelity of the models in representing experimental outcomes, we utilize a Goodness of Fit (GoF) metric, consistently yielding values exceeding 98% across all instances. By iteratively optimizing fitting parameters associated with collision efficiency, fragmentation rate, and flocs restructuring, we establish correlations with the characteristics of the polyelectrolytes employed. Subsequently, we engage in a comprehensive discussion surrounding the evolution of flocculation kinetics and scattering exponent data over time, as derived from our modeling efforts. This discussion contextualizes these findings within the broader landscape of the flocculation process, accounting for pertinent factors such as polyelectrolyte properties and varying experimental conditions. Through this multifaceted analysis, we provide insights into the intricate interplay between process dynamics and molecular attributes, facilitating a deeper understanding of flocculation phenomena.

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