TY - JOUR
T1 - Secondary Nucleation from Nuclei Breeding and Its Quantitative Link with Fluid Shear Stress in Mixing
T2 - A Potential Approach for Precise Scale-up in Industrial Crystallization
AU - Yousuf, Mustafa
AU - Frawley, Patrick J.
N1 - Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/5/17
Y1 - 2019/5/17
N2 - The development of robust process scale-up involves a clear understanding of mixing hydrodynamics in crystallization. In the present work, particle imaging velocimetry (PIV) was used to determine the fluid turbulent shear stress (TSS) as a function of scale-up involving cooling crystallization experiments at different agitation rates. At a given scale, with increased agitation rate from 300 to 370 rpm, the secondary nucleation threshold (SNT) and product mean particle size were observed to decrease due to increased TSS. In nuclei breeding, the nucleated crystals at the seed surface are readily sheared off by the increased fluid shear stress. This catalytic process enhanced the rate of secondary nucleation, and hence a decrease in SNT. The SNT and mean particle size increased with scale size due to a decrease in average turbulent dissipation rate which resulted from a decrease in TSS. Secondary nucleation due to nuclei breeding was found to have a quantitative link with TSS. This resulted in a constant SNT under the influence of the same TSS which led to a consistent particle size distribution (PSD), independent of the scale. The presented approach shows that a controlled PSD can be obtained across different crystallization scales by controlling secondary nucleation through hydrodynamics.
AB - The development of robust process scale-up involves a clear understanding of mixing hydrodynamics in crystallization. In the present work, particle imaging velocimetry (PIV) was used to determine the fluid turbulent shear stress (TSS) as a function of scale-up involving cooling crystallization experiments at different agitation rates. At a given scale, with increased agitation rate from 300 to 370 rpm, the secondary nucleation threshold (SNT) and product mean particle size were observed to decrease due to increased TSS. In nuclei breeding, the nucleated crystals at the seed surface are readily sheared off by the increased fluid shear stress. This catalytic process enhanced the rate of secondary nucleation, and hence a decrease in SNT. The SNT and mean particle size increased with scale size due to a decrease in average turbulent dissipation rate which resulted from a decrease in TSS. Secondary nucleation due to nuclei breeding was found to have a quantitative link with TSS. This resulted in a constant SNT under the influence of the same TSS which led to a consistent particle size distribution (PSD), independent of the scale. The presented approach shows that a controlled PSD can be obtained across different crystallization scales by controlling secondary nucleation through hydrodynamics.
KW - nuclei breeding
KW - particle size distribution
KW - scale-up
KW - secondary nucleation threshold
KW - turbulent shear stress
UR - http://www.scopus.com/inward/record.url?scp=85064837105&partnerID=8YFLogxK
U2 - 10.1021/acs.oprd.9b00029
DO - 10.1021/acs.oprd.9b00029
M3 - Article
AN - SCOPUS:85064837105
SN - 1083-6160
VL - 23
SP - 926
EP - 934
JO - Organic Process Research and Development
JF - Organic Process Research and Development
IS - 5
ER -