Premium
Feedback control of crystal size distribution in a continuous cooling crystallizer
Author(s) -
Rohani S.,
Paine K.
Publication year - 1991
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.5450690119
Subject(s) - slurry , dissolution , suspension (topology) , crystal (programming language) , analytical chemistry (journal) , chemistry , materials science , thermodynamics , mineralogy , chromatography , mathematics , composite material , physics , homotopy , computer science , pure mathematics , programming language
Control of crystal size distribution (CSD) in a 21.8 L continuous cooling KCl crystallizer was attempted. Feed saturated at 54°C with potash, nearly saturated with NaCl and containing 0.75 g MgSO 4 /100 g of H 2 O was cooled to the crystallizer temperature at 40°C. The control scheme consisted of a proportional‐integral controller with the rate of fines dissolution/removal as the input variable and the fines suspension density (crystals smaller than 150 μm) as the output variable. The measured/controlled variable was a temperature difference, Δ T , corresponding to the temperature of a slurry sample containing representative fines, before and after the fines were dissolved by heating. An increase in the product weight‐mean crystal size and a decrease in the coefficient of variation of product were observed in the controlled runs.