Kinetic identification and experimental validation of continuous plug flow crystallisation

Zhao, Yan; Kamaraju, Vamsi Krishna; Hou, Guangyang; Power, G.; Donnellan, Philip; Glennon, Brian

doi:10.1016/j.ces.2015.02.019

Cited by 32 publications

(34 citation statements)

References 39 publications

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“…In heterogeneous nucleation a foreign substrate initiates nuclei formation. At present, a number of authors suggest that most primary nucleation in industrial crystallizers is heterogeneous rather than homogeneous and empirical relationships such as [24][25][26][27][28]:…”

Section: Nucleation and Growth Ratementioning

confidence: 99%

Determination of Supercooling Degree, Nucleation and Growth Rates, and Particle Size for Ice Slurry Crystallization in Vacuum

et al. 2017

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Understanding the crystallization behavior of ice slurry under vacuum condition is important to the wide application of the vacuum method. In this study, we first measured the supercooling degree of the initiation of ice slurry formation under different stirring rates, cooling rates and ethylene glycol concentrations. Results indicate that the supercooling crystallization pressure difference increases with increasing cooling rate, while it decreases with increasing ethylene glycol concentration. The stirring rate has little influence on supercooling crystallization pressure difference. Second, the crystallization kinetics of ice crystals was conducted through batch cooling crystallization experiments based on the population balance equation. The equations of nucleation rate and growth rate were established in terms of power law kinetic expressions. Meanwhile, the influences of suspension density, stirring rate and supercooling degree on the process of nucleation and growth were studied. Third, the morphology of ice crystals in ice slurry was obtained using a microscopic observation system. It is found that the effect of stirring rate on ice crystal size is very small and the addition of ethylene glycoleffectively inhibits the growth of ice crystals. The results in this paper can provide theoretical guidance and technical support for the development of vacuum icemakers.

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Section: Nucleation and Growth Ratementioning

confidence: 99%

Determination of Supercooling Degree, Nucleation and Growth Rates, and Particle Size for Ice Slurry Crystallization in Vacuum

et al. 2017

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“…The jacket of the reactor was filled with air, which acted as insulation. The temperature increase over at least 5 min was recorded, and the calorimetric power (P cal ; W) was calculated using Equation (2).…”

Section: Calorimetric Power Measurementsmentioning

confidence: 99%

“…However, studies often focused on components with relatively fast nucleation kinetics [2,5,7,10]. This leaves the nucleation of molecules with slow nucleation kinetics as one of the key challenges for tubular crystallizers.…”

Section: Introductionmentioning

confidence: 99%

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Reducing the Induction Time Using Ultrasound and High-Shear Mixing in a Continuous Crystallization Process

et al. 2018

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Continuous crystallization in tubular crystallizers is of particular interest to the pharmaceutical industry to accurately control average particle size, particle size distribution, and (polymorphic) shape. However, these types of crystallizers require fast nucleation, and thus, short induction times at the beginning of the flow process, which is challenging for larger and complex organic molecules. High shear and/or the presence of bubbles were identified to influence the nucleation behavior. This work investigates the effects of both high-shear mixing and ultrasound on the anti-solvent crystallization of paracetamol in acetone-water. Both devices generate intense amounts of shear and gas bubbles. Generally, the results show that increasing input power decreases the induction time significantly for both the rotor-stator mixer and ultrasound probe. However, the induction time is almost independent of the supersaturation for the ultrasound probe, while the induction time significantly increases with decreasing supersaturation for the rotor-stator mixer. In contrast, the particle size distribution for the rotor-stator mixer is independent of the supersaturation, while increasing supersaturation decreases the particle size for the ultrasound probe.

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“…The following modeling assumptions are made (Zhao et al, 2015): 1) perfect mixing of the saturated feed solution at the inlet of the PFC; 2) there is no axial dispersion; 3) growth rate is independent of crystal size; 4) agglomeration and breakage phenomena are negligible. Therefore, a general steady-state isothermal PBM for a PFC is expressed as follows (Randolph and Larson, 1971;Myerson, 2002):…”

Section: Population Balance Modelmentioning

confidence: 99%

Particle Size Distribution and yield control in continuous Plug Flow Crystallizers with recycle

Cogoni

Souza

Frawley

2015

Chemical Engineering Science

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ABSTRACT:Crystallization of Active Pharmaceutical Ingredients (APIs) has traditionally been carried out using the batch or semi-batch manufacturing processes, techniques which remain prevalent to this day. Continuous processing affords significant production advantages including enhanced reproducibility of results, optimal control of process conditions, shorter downtime and the elimination of scale-up problems.The Plug Flow Crystallizer (PFC) is one of the most widely employed forms of continuous crystallizer. PFCs are usually selected for processes with fast kinetics and short residence times. One key limitation of PFCs, which has partially constrained their adoption in industry, is that normally they do not allow for equilibrium conditions to be achieved; this is in effect a consequence of the short residence times. Thus, the resultant yield from PFCs is generally less than that of the equivalent batch process. 2Recycling the mother liquor back through the PFC is one approach which can potentially be used in order to mitigate against this drawback, allowing for an amelioration in the continuous process yield.In the present work, the effects of introducing a recycle stream and adjusting critical recycling parameters, namely recycling ratio and axial extraction position, on an idealized PFC are examined. Particular attention is focused on the resultant volume average size of particles d 4,3 , and the process yield η. The influence of residence time on the maximum and minimum yield and size of crystals achievable is investigated. In addition, the effect of recycle parameters on the Particle Size Distribution (PSD) is ascertained, at specified values of yield.The proposed continuous PFC, as conceptualized and modelled with recycle, facilitates practical application in an industrial setting, allowing for augmented continuous process yields, whilst furthermore facilitating PSD control.

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Kinetic identification and experimental validation of continuous plug flow crystallisation

Cited by 32 publications

References 39 publications

Determination of Supercooling Degree, Nucleation and Growth Rates, and Particle Size for Ice Slurry Crystallization in Vacuum

Determination of Supercooling Degree, Nucleation and Growth Rates, and Particle Size for Ice Slurry Crystallization in Vacuum

Reducing the Induction Time Using Ultrasound and High-Shear Mixing in a Continuous Crystallization Process

Particle Size Distribution and yield control in continuous Plug Flow Crystallizers with recycle

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