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Dynamic study and control of crystal size distribution (CSD) in a KCL crystallizer
Author(s) -
Rohani S.
Publication year - 1986
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450640116
Subject(s) - slurry , particle size distribution , crystal (programming language) , spectrum analyzer , work (physics) , particle size , materials science , crystallization , particle (ecology) , process engineering , analytical chemistry (journal) , control theory (sociology) , chemistry , chemical engineering , thermodynamics , physics , chromatography , control (management) , engineering , computer science , optics , composite material , programming language , oceanography , artificial intelligence , geology
Previous works on crystal size distribution (CSD) control have indicated that a successful control scheme requires on‐line measurement of nuclei density. Such measurements can only be performed using an extremely expensive particle size analyzer. Besides the cost, the accuracy of such analyzers is restricted to low concentration slurries. In the present work an attempt is made to replace nuclei density by an alternative process variable which can be measured easily and inexpensively. Theoretical analysis of a KCl crystallizer shows that slurry density in the fines loop is an excellent substitute for nuclei density. Preliminary tests show that a turbidimeter can be used for measurement of slurry density in the fines loop. Proportional direct feedback control based on measurement of slurry concentration in the fines loop and manipulation of fines removal rate is shown to stabilize an inherently unstable crystallizer. The ability of the control scheme to suppress outside disturbances is also verified.