engleski

Kinetics of the seeded batch cooling crystallization

The influence of the seed size, loadings and the batch time on crystallization kinetics and granulometric properties of the obtained pentaerythritol crystals has been investigated. Experiments have been performed in the laboratory batch cooling crystallizer (Rushton dimensions). The solubility curve and the metastable zone width have been determined at the defined cooling profile. In order to compare the obtained results, an experiment of unseeded crystallization was performed. The experiments have been performed within the metastable zone width. For estimation of the growth kinetics, from the desupersaturation curve during batch seeded experiments, the Garside et al. method was used. The crystal growth is controlled by the surface integration (polynuclear or birth and spread mechanism of grow), since the values of the exponent of growth, g, are very high (g>2). The crystal size distribution can be approximated with the RRSB function. The smaller seed size and lower seed loadings leads to a uni-modal size distribution of the final crystals and the higher crystal growth rate. Decreasing the batch time from 80 min to 35 min, improves the final crystal size distribution, (unimodal for lower seed loadings).

cooling crystallization ; crystallization kinetics ; seeding

nije evidentirano