Quantificação da morfologia de cristais de açucar e sua aplicação ao estudo das cinéticas de cristalização

Abstract : The subject of the present thesis derives from problems related to the modelling and simulation of an industrial crystallisation unit for cane sugar production. The development of such a model raises issues related to the importance ofnucleation and agglomeration kinetics, whose knowledge should be improved. The first part describes the development of a image analysis-based tool that allows a better characterisation of the properties of crystals in terms of their size distribution but also their morphological properties, especially their degree of agglomeration. The second part describes the design and setting-up of a laboratory facility for sugar crystallisation. The experiments were conducted in pure sucrose/water systems - changing the supersaturation, temperature, agitation speed and seeding - and in systems where known amounts of chemical impurities, usually present in industrial solutions, were added. Finally, a model for the laboratory crystalliser was developed. It allows the simulation of the profile versus time of sucrose concentration in solution, of the crystal size distribution and of the agglomeration degree distribution. The model proved to be adequate to the case study particularly ,in describing properties closely related to agglomeration phenomena. The main difficulties had to do with the absence of experimental data concerning crystal size distribution and agglomeration degree distribution time trajectories. The main contribution or the present work was the development of image analysis tools that allow the quantification of sucrose crystals morphology, the introduction of the degree of agglomeration concept and the proposal of a model that allows, for the first time, the description of the degree agglomeration distribution as a function of crystal size.
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Theses
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http://docnum.univ-lorraine.fr/prive/INPL_T_2002_COSTA_MARTINS_DE_FARIA_N.pdf
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https://hal.univ-lorraine.fr/tel-01747333
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Submitted on : Thursday, March 29, 2018 - 10:57:28 AM
Last modification on : Thursday, January 31, 2019 - 1:27:48 AM

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Nuno Costa Martins de Faria. Quantificação da morfologia de cristais de açucar e sua aplicação ao estudo das cinéticas de cristalização. Alimentation et Nutrition. Institut National Polytechnique de Lorraine, 2002. Français. ⟨NNT : 2002INPL023N⟩. ⟨tel-01747333⟩

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