Intensification of falling film melt crystallization process through micro and milli-structured surfaces

Mostefa, Marie Le Page; Muhr, Hervé; Biget, Anthony; Palasari, Edouard; Fauconet, Michel

doi:10.1016/j.cep.2015.02.006

Cited by 9 publications

(5 citation statements)

References 7 publications

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“…According to the principle of the thermal-electrical analogy, the overall resistance of the liquid melt, R L , is calculated using Equation (12). Considering the crystal layer slice as a continuous phase, the heat resistance of the crystal phase R C is given by Equation (13), where λ c represents the thermal conductivity of the solid phase.…”

Section: Thermal Property Parametersmentioning

confidence: 99%

“…Wang et al 12 proposed a new type of countercurrent melt crystallizer with a multistage sieve plate and discussed several key factors in the separation efficiency, including the stirring rate and settling velocity of the crystal particles. Mostefa et al 13 designed micro-and milli-structured surfaces of crystallizers to intensify heat and mass transfer. Other intensification pathways, including technique coupling, crystallizer surface modification, crystal seed optimization, and bubble-induced crystallization, have been reviewed by Shen et al 2 Solute transfer and impurity migration directly determine the separation efficiency of the LMC.…”

Section: Introductionmentioning

confidence: 99%

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Performance and analysis of key factors on the design of melt crystallization‐based separation process

Jia

Gao

et al. 2023

AIChE Journal

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This study combines theoretical models with experiments to analyze the impurity migration mechanism and obtain the key factors of separation optimization for the design of layer melt crystallization. The fractal slice model was used to explore pore structure formation and calculate the heat properties of the crystal layer. It was found that the fractal characteristics approached the features of Euclidean geometry with increasing porosity, and the thermal conductivity showed a linear decrease with the porosity. Three kinetic models were established based on the temperature difference to reveal quantitative correlations with the degree of supercooling (or superheating). The effects of the pore structure, kinetic behavior, and sweating intensity on the separation process are highlighted. Finally, this work analyzed the important roles of kinetic factors and impurity migration distribution, where a qualitative analysis revealed that the kinetic effect was important in impurity migration in the sweating process.

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Section: Thermal Property Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Performance and analysis of key factors on the design of melt crystallization‐based separation process

Jia

Gao

et al. 2023

AIChE Journal

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“… 9 − 14 In static melt crystallization, because of no mixing device, the melt growth is only caused by natural convection. 15 However, in the process of dynamic falling film crystallization and suspension crystallization, the crystal grows from the well-mixed melt caused by stirring or pumping, leading to high-quality transportation of the crystal surface and the impurities into the melt. 16 Therefore, compared with the static process, the dynamic process has a higher separation efficiency when the crystal growth rate is similar or even faster.…”

Section: Introductionmentioning

confidence: 99%

“…Accordingly, the melt crystallization method, which includes static melt crystallization, dynamic falling film melt crystallization, and suspension crystallization, has the advantages of high product purity, energy saving, and low requirements in equipment, was especially suitable for the separation of the heat-sensitive mixtures with similar boiling points. − In static melt crystallization, because of no mixing device, the melt growth is only caused by natural convection . However, in the process of dynamic falling film crystallization and suspension crystallization, the crystal grows from the well-mixed melt caused by stirring or pumping, leading to high-quality transportation of the crystal surface and the impurities into the melt .…”

Section: Introductionmentioning

confidence: 99%

Purification of MDI Isomers Using Dynamic Falling Film Melt Crystallization: Experiment and Molecular Simulation

Lian

Wang

et al. 2022

ACS Omega

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In this work, the isomer mixture of 4,4′-diphenylmethane diisocyanate (MDI) and 2,4′-MDI was separated and purified by dynamic falling film melt crystallization, and 99.3% purity and 50.8% yield of 4,4′-MDI could be obtained under optimized conditions. The separation mechanism was simulated by density functional theory (DFT) and molecular dynamics (MD) simulation. Results showed that compared with 2,4′-MDI, 4,4′-MDI molecules could form a more stable and symmetrical crystal structure due to their stronger charge density symmetry and electrostatic potential energy. Furthermore, the separation phenomenon and the formation of the crystal structure were observed according to the radial distribution function (RDF) and orientation correlation function obtained from MD simulation. Finally, the attachment energy (AE) model was used to observe and compare different crystal surfaces; it was proposed that the aggregation of 4,4′-MDI was attributed to the polar attraction between isocyanate groups according to the results of the orientation correlation function. It was also observed that compared with 2,4′-MDI, 4,4′-MDI molecules on the (110) crystal surface were easier to form crystal structures.

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“…Due to the close boiling points between AA (141 • C) and PA (141.15 • C), it is usually difficult to separate them by distillation. In recent years, melt crystallization has been applied to separate AA from melt with impurity PA [19][20][21]. To elucidate the influence of process parameters on the effective distribution coefficient, the objective of this study is to investigate the dependence of the effective distribution coefficient on the initial impurity concentration and layer growth rate for AA melt with PA as an impurity for industrial applications.…”

Section: Introductionmentioning

confidence: 99%

The Correlation for Effective Distribution Coefficient with Initial Impurity Concentration and Growth Rate for Acrylic Acid in Melt Crystallization

Shiau

2022

Crystals

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The layer growth rates and resulting crystal purity during solid-layer melt crystallization were experimentally measured for acrylic acid (AA) with impurity propionic acid (PA) operated at various cooling temperatures. A power law was adopted to correlate the growth rate with the temperature difference between melt and coolant. The effective distribution coefficient was determined from the resulting crystal purity for each condition. An empirical equation modified from the analytical solution for the mass transfer boundary layer was proposed in this work to relate the effective distribution coefficient to the initial impurity concentration and growth rate.

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Intensification of falling film melt crystallization process through micro and milli-structured surfaces

Cited by 9 publications

References 7 publications

Performance and analysis of key factors on the design of melt crystallization‐based separation process

Performance and analysis of key factors on the design of melt crystallization‐based separation process

Purification of MDI Isomers Using Dynamic Falling Film Melt Crystallization: Experiment and Molecular Simulation

The Correlation for Effective Distribution Coefficient with Initial Impurity Concentration and Growth Rate for Acrylic Acid in Melt Crystallization

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