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Importance of macromixing in batch cooling crystallization
Author(s) -
Bohlin Martin,
Rasmuson Åke C.
Publication year - 1996
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690420310
Subject(s) - supersaturation , nucleation , crystallization , suspension (topology) , mixing (physics) , chemistry , unit operation , process (computing) , chemical engineering , materials science , chemical physics , thermodynamics , organic chemistry , physics , mathematics , quantum mechanics , homotopy , pure mathematics , engineering , computer science , operating system
The importance of spatial variations of the conditions in industrial‐scale, agitated, batch cooling crystallizers is investigated by computer simulations. A three‐compartment model is developed considering primary and magma density‐dependent secondary nucleation. An increasing crystallizer size is described by an increasing suspension turnover time. It is shown that accumulation of larger crystals in the bottom region, localized supersaturation generation and variations in the secondary nucleation rate due to varying local mixing intensity will, under normal conditions, exert a low and often negligible influence on the product‐size distribution of an industrial unit. In a batch process, the product‐size distribution is governed mainly by the conditions early in the process. During this period the supersaturation half‐life is much longer than the suspension turnover time, and the influence of local variations becomes weak.