Mechanisms of initiation of incrustation

Vendel, Martin; Rasmuson, Åke C.

doi:10.1002/aic.690430518

Cited by 20 publications

(12 citation statements)

References 12 publications

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“…Thus, there exists a combination of deterministic and stochastic processes occurring simultaneously. Similar processes occur during the fouling of tubular heat exchangers [38] and crystallizers [37]. While recognising the importance of agglomeration, this is not considered further in this article.…”

Section: Chemical Engineering Approach To Modelling Crystallization Imentioning

confidence: 94%

Reverse engineering the kidney: modelling calcium oxalate monohydrate crystallization in the nephron

Borissova

Goltz

Kavanagh

et al. 2010

Med Biol Eng Comput

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Crystallization of calcium oxalate monohydrate in a section of a single kidney nephron (distal convoluted tubule) is simulated using a model adapted from industrial crystallization. The nephron fluid dynamics is represented as a crystallizer/separator series with changing volume to allow for water removal along the tubule. The model integrates crystallization kinetics and crystal size distribution and allows the prediction of the calcium oxalate concentration profile and the nucleation and growth rates. The critical supersaturation ratio for the nucleation of calcium oxalate crystals has been estimated as 2 and the mean crystal size as 1 mum. The crystal growth order, determined as 2.2, indicates a surface integration mechanism of crystal growth and crystal growth dispersion. The model allows the exploration of the effect of varying the input calcium oxalate concentration and the rate of water extraction, simulating real life stressors for stone formation such as dietary loading and dehydration.

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Section: Chemical Engineering Approach To Modelling Crystallization Imentioning

confidence: 94%

Reverse engineering the kidney: modelling calcium oxalate monohydrate crystallization in the nephron

Borissova

Goltz

Kavanagh

et al. 2010

Med Biol Eng Comput

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show abstract

“…Nucleation events in the bulk solution are mainly homogeneous nucleation and secondary nucleation triggered by seed crystals; nonetheless, secondary nucleation is the dominating nucleation mechanism in industrial crystallizers given the wide use of seeding, while homogeneous nucleation is negligible unless the crystallization process operates in the high supersaturation zone without seeding. In contrast, encrustation can be initiated through heterogeneous nucleation at the surface when local supersaturation is high or by adsorption of the crystals or crystal nuclei during collision onto solid surfaces at low local supersaturation levels. , Since the growth rates of the crystals and encrustation are expected to be similar for a given solution, competition between the nucleation mechanisms strongly affects the formation of encrustation. Many factors affect the rates of the different nucleation mechanisms.…”

Section: Literature Reviewmentioning

confidence: 99%

“…In contrast, encrustation can be initiated through heterogeneous nucleation at the surface when local supersaturation is high or by adsorption of the crystals or crystal nuclei during collision onto solid surfaces at low local supersaturation levels. 26,27 Since the growth rates of the crystals and encrustation are expected to be similar for a given solution, 1 competition between the nucleation mechanisms strongly affects the formation of encrustation. Many The rate at which encrustation forms and/or crystals grow depends on the nucleation and growth kinetics of the system.…”

Section: Literature Reviewmentioning

confidence: 99%

Encrustation in Continuous Pharmaceutical Crystallization Processes—A Review

Acevedo

Yang

Liu

et al. 2019

Org. Process Res. Dev.

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Encrustation is a risk factor that can cause product and process failure in continuous crystallization processes. Mitigation, prevention, and control of encrustation have been extensively researched. Various risk mitigation strategies proposed in the literature, such as coating of crystallizer walls, use of additives to control encrustation kinetics, and periodic steady-state operation show promising results in delaying or preventing encrustation. Because of the increased interest in the use of continuous crystallization in industrial applications, it is important to understand this risk factor further. This review presents recent developments on dynamic models, mechanisms, and risk factors for encrustation in continuous crystallization processes. Various design and control strategies to mitigate the encrustation risk are also summarized. Appropriate control strategies should be implemented during continuous crystallization to avoid the impact of encrustation on drug substance quality.

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“…It is found that at high supersaturation, the solid surface may initiate encrustation by catalyzing primary nucleation. Conversely, at a reasonably low supersaturation, collision of the crystals with the solid surface may initiate encrustation . Crystal nucleation, deposition, and growth may also occur simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Modeling of Encrust Formation and Mitigation Strategy in a Continuous Plug Flow Crystallizer

Majumder

Nagy

2015

Crystal Growth & Design

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Encrustation, also known as fouling or scale formation, on the wall of plug flow crystallizers (PFC) can cause major operational and economic problems in pharmaceutical industries. These include increased energy requirements due to increment of thermal resistance and pressure drop, and clogging of the crystals due to reduction of flow area. In this work, a mathematical model for predicting the dynamic behavior of a PFC undergoing encrustation is presented. This model describes the formation of encrust layer by considering various mechanisms such as rate of solute transport from bulk to the wall, integration and removal due to shear stress induced by fluid turbulence. A population balance model for describing the crystallization process in the PFC is also coupled with the encrustation model in order to obtain the appropriate concentration profile in the PFC as well as product crystal size distribution (CSD). Based on this model, a mitigation strategy is proposed that relies on injection of pure solvent to dissolve the encrust layer.

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Mechanisms of initiation of incrustation

Abstract: Initiaton of incrustation by crystallization mechanisms is

Cited by 20 publications

References 12 publications

Reverse engineering the kidney: modelling calcium oxalate monohydrate crystallization in the nephron

Reverse engineering the kidney: modelling calcium oxalate monohydrate crystallization in the nephron

Encrustation in Continuous Pharmaceutical Crystallization Processes—A Review

Dynamic Modeling of Encrust Formation and Mitigation Strategy in a Continuous Plug Flow Crystallizer

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