Kinetic studies on the influence of temperature and growth rate history on crystal growth

• Tipo: Artigo em Revista Científica Internacional
• Data: 2008

Autores

Martins, PM (Autor) FEUP; Rocha, FA (Autor) FEUP

Revista

Título: Crystal Research and Technology

Vol. 43 Nº 12

Páginas: 1258-1267

ISSN: 0232-1300

Editora: Wiley-Blackwell

Indexação

ISI Web of Knowledge - 5 Citações

ISI Web of Science

Scopus - 5 Citações

INSPEC

COMPENDEX

Classificação Científica

FOS: Ciências exactas e naturais > Química

CORDIS: Ciências Tecnológicas > Engenharia > Engenharia química

Outras Informações

ID Authenticus: P-003-TD5

DOI: 10.1002/crat.200800301

Abstract (EN): Crystallization experiments of sucrose were performed in a batch crystallizer to study the effect of temperature and growth rate history on the crystal growth kinetics. In one of the growth methods adopted, the isothermal volumetric growth rate (R(V)) is determined as a function of supersaturation (S) at 35, 40 and 45 degrees C. In the other, crystals are allowed to grow at constant supersaturation by automatically controlling the solution temperature as the solute concentration decreased. Using the latter method R(V) is calculated as the solution is cooled. The obtained results are interpreted using empirical, engineering and fundamental perspectives of crystal growth. Firstly, the overall activation energy (EA) is determined from the empirical growth constants obtained in the isothermal method. The concept of falsified kinetics, widely used in chemical reaction engineering, is then extended to the crystal growth Of Sucrose in order to estimate the true activation energy (ET) from the diffusion-affected constant, E, The differences found in the isothermal and constant supersaturation methods are explained from the viewpoint of the spiral nucleation mechanism, taking into account different crystal surface properties caused by the growth rate history in each method. Finally, the crystal growth curve obtained in the batch crystallizer at 40 degrees C is compared with the one obtained in a fluidized bed crystallizer at the same temperature. Apparently divergent results are explained by the effects of crystal size, hydrodynamic conditions and growth rate history on the crystallization kinetics of sucrose. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 10