Criteria for the Selection and Design of Crystallizers

The determination of the main dimensions of classifying crystallizers is briefly discussed in the following. For a comprehensive design method, see References [7.1, 7.39, 7.51]. In a classifying crystallizer, such as the Oslo and Messo crystallizer, a separation effect is caused by the different sedimentation behavior of different grain sizes in the upflowing solution. 

If fresh solution Fj is mixed with circulated mother liquor and supersatured in 

The supersaturation of the solution is reduced as it flows through the crystal bed of the crystallizer. A sufficient crystal bed height and solution residence time in the crystal bed are required for this. 

Therefore, the required cross-sectional area Aq of a cylindrical crystallizer is 

The specific crystalline rate (output per unit cross-sectional area) S/Aq of classify- 

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