Premium
Effect of scale of operation on CSD dynamics in evaporative crystallizers
Author(s) -
Jager Johan,
Kramer Herman J. M.,
Scarlett Brian,
De Jong Esso J.,
De Wolf Sjoerd
Publication year - 1991
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.690370204
Subject(s) - supersaturation , chemistry , dissolution , suspension (topology) , thermodynamics , mechanics , mineralogy , physics , mathematics , organic chemistry , homotopy , pure mathematics
Experimental measurements of the crystal‐size distribution (CSD) clearly indicate a pronounced difference in the dynamic behavior of a 20‐ and 970‐L continuous crystallizer that produces ammonium sulfate. The difference in their circulation time offers a probable explanation for this phenomenon. It causes different supersaturation profiles in the two crystallizers, which leads to internal fines dissolution in the large crystallizer. This contributes to the observed oscillations in the 970‐L crystallizer as opposed to the first‐order responses in the 20‐L crystallizer. To numerically study the effect of the supersaturation profile a dynamic model, from which the MSMPR (mixed suspension mixed product removal) assumption is omitted, is developed. Calculated supersaturation profiles differ considerably for the 20‐L, the 970‐L and an imaginary 50,000‐L continuous evaporative crystallizer. Coincident with changes in the supersaturation profiles, the numerical solution of the model indicates the tendency of large crystallizers to oscillate and supports this suggested explanation.