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Journal ArticleDOI

Kinetics of melt crystallization in falling films

01 Feb 1999-Chemical Engineering Communications (Taylor & Francis Group)-Vol. 171, Iss: 1, pp 29-53
TL;DR: In this paper, an analysis of the solidification rates of binary mixture melts flowing as a thin film on a cold surface is presented, useful in the separation or purification of eutectic mixtures.
Abstract: An analysis of the solidification rates of binary mixture melts flowing as a thin film on a cold surface, useful in the separation or purification of eutectic mixtures, is presented. The analysis which incorporates the hydrodynamics of the falling film and the convective heat transfer at the melt/crystal interface was used to determine the average crystallization velocity. The effect of parameters such as Stefan number (subcooling), initial superheat and the melt loading rate on the average crystallization velocity was examined. Experiments were performed using three different binary organic mixtures at subeutectic compositions. The results of the theoretical and experimental studies showed good agreement validating the model.
Citations
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Journal ArticleDOI
TL;DR: In this article, a detailed model of the crystal layer growth and multi-ion impurity distribution process in the falling film melt crystallization (FFMC) model was developed and validated.

41 citations

Journal ArticleDOI
TL;DR: In this article, a review of the research progress and process model development of the key processes (crystal layer growth and impurity distribution) involved in layer melt crystallization is presented.
Abstract: Layer melt crystallization has been widely utilized in numerous chemical industries because of its high selectivity for pure products, low energy consumption, and the convenience to industrialization. This review will lay out the research progress and process model development of the key processes (crystal layer growth and impurity distribution) involved in layer melt crystallization. First, the nucleation mechanism, the preparation approaches of the initial crystal layer, and classic experimental configurations are illustrated. Second, modeling approaches are outlined to release the progress of separation effect evaluation, parameter optimization, and sweating process simulation in layer melt crystallization. Novel theories (fractal, porous media, and so on) and technologies (gradient freezing, sonocrystallization, and so forth) with suitable interpretation are potential solutions for the shortcomings of the current process research. Consequently, application areas related to layer melt crystallization a...

37 citations

Journal ArticleDOI
TL;DR: In this paper, a distilliation/melt crystallization hybrid process is optimized by realistically describing crystallization separation efficiency and by implementing sweating, and the required crystallization models are presented and experimentally validated.
Abstract: Layer melt crystallization is a highly selective method for the separation of narrow boiling mixtures which are difficult to separate with conventional separation techniques like distillation due to low driving forces. Contrawise, layer melt crystallization has the drawback of limited capacity due to the direct connection between crystal product and required cooled surface. Here, the combination of the high throughput distillation and highly selective layer melt crystallization into an integrated hybrid process can lead to enormous benefits. Since the separation efficiency of the crystallization is not predictable, it has to be described with empirical correlation. Here, studies from literature use strongly simplified correlations by, e.g. assuming complete separation. This bears the serious risk of overestimating the efficiency of the hybrid process. Further, the effective post purification step sweating was not implemented into hybrid processes in studies from literature. This study fills this gap in literature. A distilliation/melt crystallization hybrid process is optimized by realistically describing crystallization separation efficiency and by implementing sweating. The required crystallization models are presented and experimentally validated. The optimization of the hybrid process is done with different modelling depths and the results underline impressively the importance of the adequate description of the crystallization separation efficiency.

25 citations

Journal ArticleDOI
TL;DR: In this paper, the growth behaviors of crystal layers during static layer melt crystallization were studied from the perspectives of morphology structure, growth rates and temperature evolution, and the temperature distributions of the melt and crystal layer were deduced.

16 citations

References
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Journal ArticleDOI
TL;DR: In this article, an approximate analysis of the growth of, and the temperature within, a deposit which may occur in a cold surface in a gas stream is developed with the convective heat transfer to the surface of the deposit taken into account.

29 citations