Micromixing in a static mixer and an empty tube by a chemical method

Meyer, Thierry; David, René; Renken, Albert; Villermaux, J.

doi:10.1016/0009-2509(88)87068-4

Cited by 22 publications

(6 citation statements)

References 10 publications

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“…Figure shows that smaller crystals with a narrower size distribution were obtained when static mixers were used. As reported by Meyer, characteristic mixing time in an empty pipe is 1 order of magnitude bigger than the mixing time for a pipe with static mixers . As a consequence, in the experiment without static mixers the nucleation and growth of flufenamic acid had already started before micromixing in the empty crystallizer was complete, and the crystal size distribution resulting was much wider as evidenced by the higher values of coefficient of variation.…”

Section: Resultsmentioning

confidence: 67%

“…As reported by Meyer, characteristic mixing time in an empty pipe is 1 order of magnitude bigger than the mixing time for a pipe with static mixers. 48 As a consequence, in the experiment without static mixers the nucleation and growth of flufenamic acid had already started before micromixing in the empty crystallizer was complete, and the crystal size distribution resulting was much wider as evidenced by the higher values of coefficient of variation. This observation is consistent with the results reported by Mahajan for crystallization of lovastatin in two impinging jet precipitators, 20 as well as Raphael for crystallization of sunflower proteins in a tubular reactor, where operation at poorly mixed conditions resulted in large crystals with wider CSD.…”

Section: Population Balance Modelmentioning

confidence: 99%

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Continuous Plug Flow Crystallization of Pharmaceutical Compounds

Álvarez

Myerson

2010

Crystal Growth & Design

286

328

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Crystallization processes in the pharmaceutical industry are usually designed to obtain crystals with controlled size, shape, purity, and polymorphic form. Knowledge of the process conditions required to fabricate crystals with controlled characteristics is critical during process development. In this work, continuous crystallization of ketoconazole, flufenamic acid, and L-glutamic acid in a nonconventional plug flow crystallizer was investigated. Kenics type static mixers were used to promote homogeneous mixing of active pharmaceutical ingredient solution and antisolvent. A strategy of multiple points of addition of antisolvent along the crystallizer was evaluated to control the size of the crystals. Interestingly, it was found that crystal size can be increased or decreased with an increased number of antisolvent addition points, depending on the kinetics of the system. It was also found that smaller crystals with a narrower size distribution can be obtained with the static mixers. A model to describe the continuous crystallization process was developed through the simultaneous solution of a population balance equation, kinetics expressions for crystal growth and nucleation, and a mass balance. The comparison of experimental and calculated values for crystal size distribution revealed that a growth rate dispersion model could describe accurately the continuous crystallization process. Collision of crystals with each other and with mixing elements inside the crystallizer may be the source of random fluctuation of the growth rate in the nonconventional plug flow crystallizer with static mixers.

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Section: Resultsmentioning

confidence: 67%

Section: Population Balance Modelmentioning

confidence: 99%

Continuous Plug Flow Crystallization of Pharmaceutical Compounds

Álvarez

Myerson

2010

Crystal Growth & Design

286

328

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“…Meyer et al investigated micromixing, i.e., mixing on a molecular length scale, for laminar flow in pipes with static mixers and empty pipes. They reported that the performance of the static mixer was an order of magnitude superior to a tube with no mixing elements . The enhanced mixing of the static mixers is due to a higher rate of energy dissipation.…”

Section: Results and Discussionmentioning

confidence: 99%

“…They reported that the performance of the static mixer was an order of magnitude superior to a tube with no mixing elements. 45 The enhanced mixing of the static mixers is due to a higher rate of energy dissipation. Moreover, other authors have reported that the CFI mixer offers a higher mixing efficiency as compared to static mixers, 33,46 and it produces a lower pressure drop.…”

Section: Resultsmentioning

confidence: 99%

Process Intensification of Continuous Antisolvent Crystallization Using a Coiled Flow Inverter

Benitez-Chapa

Nigam

Álvarez

2019

Ind. Eng. Chem. Res.

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The present work experimentally studies the antisolvent continuous crystallization of flufenamic acid using the coiled flow inverter (CFI) as a novel crystallization device. A multistage antisolvent addition strategy was evaluated. The experimental results show that the mean crystal size increased with the number of antisolvent addition points in the CFI. The continuous CFI crystallizer produced crystals of a smaller size with narrower size distributions as compared to the Kenics crystallizer and tube crystallizer without mixing elements at the same process conditions. The effect of the number of flow inversions on the size distribution of the flufenamic acid crystals was studied. The mean crystal size and the coefficient of variation decreased as the number of equally spaced 90° bends increased. Using the population balance equation, it was found that an ideal plug flow model can accurately describe the CFI continuous crystallization process. Overall, this work shows that the CFI crystallizer successfully intensifies the continuous antisolvent crystallization process.

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“…Whereas for co-polymerizations, the time of micromixing will strongly influence the product characteristics in terms of mean molecular mass and its distribution on one hand, and the composition distribution and the sequence of monomer units on the other hand. In order to investigate and estimate the degree of micromixing, a novel test reaction using in-line sensor was developed and tested [23][24][25]. mixing efficiencies.…”

Section: Micromixingmentioning

confidence: 99%