Naslov
The influence of the crystallizer geometric characteristics on the crystal granulometric properties

Autori
Sander, Aleksandra ; Gelemanović, Andreja ; Hrkovac, Martina ; Šimić, Nives

Izvornik
Chemical Engineering transactions (1974-9791) 17 (2009); 765-770

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, kongresni rad, znanstveni

Ključne riječi
crystallization; geometric characteristics; granulometric properties; scale-up

Sažetak
In order to determine the influence of the crystallizer geometric characteristics and the cooling profile on the obtained crystals geometric properties (shape, size and crystal size distribution), batch cooling crystallization of potassium chloride from the water solution have been performed. The measurements were undertaken on the laboratory scale in three geometrically similar crystallizers (flat bottom) and one round bottom crystallizer under stirring intervals from 300 to 600 min -1. A stirrer was supplied with pitched (at a 45°) 4-blade propeller. Hydrodynamic conditions in the crystallizer, size and geometric characteristics of the equipment had major influence on the properties of the crystals. Under higher stirring rate and with bigger equipment the crystals assumed more regular shape and their size distribution showed finer fractions. Actually, these conditions reduced the amount of agglomerates in the finished product. In addition, more favourable hydrodynamic conditions for heat and mass transfer were achieved, whereas the secondary nucleation (contact) was minor. Two cooling profiles were used: linear and combined profile (linear followed with natural cooling). Crystals of higher quality (less agglomerates and more uniform CSD) were obtained in the round bottom crystallizer for linear cooling rate. Better hydrodynamics conditions were achieved, so nucleation starts at lower supersaturation levels (higher temperatures). More agglomerates were formed with the combined cooling rate (longer retention time).

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo

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