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Crystal size distribution dynamics in a classified crystallizer: Part II. Simulated control of crystal size distribution
Author(s) -
Beckman James R.,
Randolph Alan D.
Publication year - 1977
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.690230416
Subject(s) - instability , slurry , control limits , crystal (programming language) , population , particle size distribution , chemistry , constant (computer programming) , yield (engineering) , control theory (sociology) , mathematics , mechanics , materials science , thermodynamics , physics , particle size , control (management) , computer science , programming language , demography , process (computing) , control chart , artificial intelligence , sociology , operating system
Control of sustained limit‐cycle instability in crystal size distribution (CSD) was simulated for a class II (high yield) crystallizer equipped with a fines destruction system and product classifier. Control was simulated by proportional control of nuclei density using fines destruction rate as the manipulated variable. The control constant necessary to eliminate instability was theoretically predicted and agreed with the constant found via simulation. Poorer control of CSD (inability to completely eliminate limit cycles) was predicted using slurry density and slurry withdrawal rate as the measured and manipulated variables, respectively. Development of techniques for fine crystal population measurements to estimate nuclei density are necessary for implementation of the former control scheme. The suggested nuclei density control scheme is effective both in minimizing CSD transients and for elimination of instability.