Model-based design of pressure-driven product removal from stirred suspensions

Achermann, Ramona; Wiedmeyer, Viktoria; Hosseinalipour, Mercedeh Sadat; Güngör, Selin; Mazzotti, Marco

doi:10.1016/j.cherd.2021.07.001

Cited by 6 publications

(14 citation statements)

References 23 publications

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“…where ε i,k represents the polymorph-specific degree of dilution and δ i,k the extent of the sieving effect, which is characterized by the sizedependent function ω i,k (x). 19 On the one hand, since different polymorphs can crystallize in different shapes and grow at different rates, their dilution factors can differ as well; the higher its value, the lower the solid suspension density of the outlet stream and the longer the particles' residence time. This may alter the nature of the steadystate attained.…”

Section: Constitutive Equationsmentioning

confidence: 99%

“…The analytical solution is only for cases featuring a single polymorphic crystal distribution at steady-state. 19 2.2. Key Performance Indicators.…”

Section: Examples Of Applicationmentioning

confidence: 99%

“…The suspension transfer from MSMPR1 to MSMPR2 and from MSMPR2 to the final collector tank was pressure-driven and occurred intermittently, as explained in detail elsewhere. 19 A check valve was installed at the outlet of the MSMPR1 to avoid the backflow of air during the pressurization of the MSMPR2. A level control was installed in each crystallizer, which triggered the pressurization once a specified fill level height was reached.…”

Section: Examples Of Applicationmentioning

confidence: 99%

“…15,21,22 However, crystals of that polymorph distribute heterogeneously within the crystallizer, and therefore, a representative withdrawal is operationally challenging. 19 βLGA forms needle-like crystals, which are difficult to handle industrially and normally require further processing before usage, yet suspension heterogeneity is not an issue. 5 The goal of this work is to produce both polymorphs of the model compound LGA with the highest attainable process performance, accounting for operational challenges for which both modeling and experiments are required.…”

Section: Introductionmentioning

confidence: 99%

“…To improve process control, the effect of a nonrepresentative withdrawal inside an MSMPR was previously studied, and an expression accounting for nonidealities was proposed . These nonidealities were modeled using computational fluid dynamics (CFD) tools.…”

Section: Introductionmentioning

confidence: 99%

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Process Performance and Operational Challenges in Continuous Crystallization: A Study of the Polymorphs of L-Glutamic Acid

Achermann

Košir

Bodák

et al. 2023

Crystal Growth & Design

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The crystallization of the two polymorphs of l-glutamic acid (LGA) is carried out in a continuous crystallization process, and its performance according to different criteria is evaluated. The study aims at identifying suitable operating conditions for producing either αLGA or βLGA with a high polymorphic purity. To this end, we investigate the process both from a theoretical perspective and through experiments using either a single stirred-tank crystallizer or a cascade of two stirred-tank crystallizers in series. In terms of theory, we extend the MSMPR-based steady-state stability analysis of Farmer et al. (AIChE J.20166235053514) by accounting for the possibility of a nonrepresentative withdrawal of the solid phase from the crystallizer. Additionally, the process is simulated using population balance equations, thereby investigating the effect of operating conditions on polymorphic purity, yield, and productivity. Guided by the model-based conclusions, we identified suitable operating conditions and experimentally tested them. The experimental campaign has demonstrated that βLGA could be successfully and continuously produced in both process configurations according to the theory with performance as expected, whereas that was not possible for αLGA. The difference between the two stems from different operational challenges, whose consequence is that steady-state operation is attained in the case of βLGA but not in that of αLGA. In the former case, the needle-like βLGA crystals, which exhibit no agglomeration, tend to be only slightly oversampled; in the latter case, the prismatic αLGA crystals undergo major agglomeration and hence are very difficult to suspend and effectively withdraw from the crystallizer.

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Section: Constitutive Equationsmentioning

confidence: 99%

“…The analytical solution is only for cases featuring a single polymorphic crystal distribution at steady-state. 19 2.2. Key Performance Indicators.…”

Section: Examples Of Applicationmentioning

confidence: 99%

Section: Examples Of Applicationmentioning

confidence: 99%