Investigation of crystal growth of borax in single and dual impeller batch cooling crystallizer |
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Authors: | Marija ?osi? Antonija ?elan Igor Pehnec Nenad Kuzmani? |
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Affiliation: | 1. Department of Chemical Engineering, Faculty of Chemistry and Technology, University of Split, Split, Croatia;2. akrap@ktf-split.hr;4. Department of Mechanical Engineering and Naval Architecture, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, University of Split, Split, Croatia |
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Abstract: | AbstractThe purpose of this work was to investigate and compare the influence of fluid flow in a single and dual impeller batch cooling crystallizer on crystal growth kinetics of borax decahydrate. Examinations were conducted in a crystallizer of 15?dm3 stirred by a single pitched blade turbine and straight blade turbine as well as their dual configurations. Kinetics parameters of crystal growth determined at applied mixing conditions were correlated with hydrodynamic conditions. In this paper, hydrodynamics was characterized by mixing time, which was experimentally determined, and by fluid flow patterns, which were simulated by the means of computational fluid dynamic (CFD). It was found that although the crystal growth in all systems investigated was controlled by the integration mechanism, the crystal growth rate constant changed significantly with impeller configuration. Regarding the characteristics of the final product, a dependence of the crystal size distribution on the fluid flow pattern was noticed while the number of impellers did not affect the product properties. On the other hand, mixing efficiency differed significantly with the type and number of impellers. |
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Keywords: | CFD Crystal growth Dual-impeller crystallizer Fluid flow pattern Mixing efficiency Mixing time |
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