Evaluation for the distillation of viscous mixtures in packed colomns - A theoretical and experimental approach
Final Report Abstract
Distillation is the most widely used separation process in the chemical industry and accordingly well studied. However, research activities have mainly been focused on mixtures with low viscosities. Consequently, despite the industrial relevance of such systems (e.g. in the production of plastics), knowledge about the influence of high viscosity on the separation performance is limited. In cooperation between TU Braunschweig and Paderborn University, a systematic investigation on the distillation of viscous mixtures in structured packings was carried out. For this purpose, both experimental methods and model-based methods were coupled with each other. The experimental methods included separation efficiency measurements, while a viscosity-increasing polymer was added to a binary solvent mixture. In addition, viscosity-induced changes in the flow morphology within the packing were accessed by X-ray tomographic measurements in collaboration with the University of Liége. The model-based description of the separation performance was accomplished based on hydrodynamic analogy concept, while relevant flow phenomena were identified with the tomographic measurements and implemented accordingly. Furthermore, the polymer-enhanced test mixtures were characterized with respect to their mixture properties, and the results were implemented in the modelling. Simulations with viscosities of up to 50 mPa·s were conducted. Compared to commonly used test mixtures, this viscosity increase corresponds to a factor of 100 and resulted in significantly lowered separation efficiencies. Detailed simulation studies showed that this reduction is mainly caused by changes in flow patterns, whereas the viscosity influence on diffusion has a minor influence. Due to the non-evaporating polymer, a novel test plant was required for the separation efficiency measurements. Such a plant was developed and built in ID = 50 mm scale. After successful commissioning and testing with polymer-free mixtures, separation efficiency measurements were carried out with mixture viscosities of up to 5 mPa·s under distillative conditions.
Publications
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(2018): Charakterisierung geeigneter Stoffgemische für Trennleistungsmessungen bei erhöhten Viskositäten. ProcessNet-Jahrestagung, Aachen
Gutperl, S., Scholl, S.
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(2019), Liquid flow morphology of viscous systems in structured packings: investigations by X-ray tomography. 14th International Conference on Chemical and Process Engineering, Bologna, Italien
Bolenz, L., Toye, D., Kenig, E. Y.
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(2019),Tomographische Untersuchung der Fluiddynamik viskoser Systeme in Packungskolonnen. Chemie Ingenieur Technik 91, 1892-1896
Bolenz, L., Fischer, F., Toye, D., Kenig, E.Y.
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(2019): Trennleistungsmessungen mit Stoffgemischen erhöhter Viskosität und nicht-verdampfenden Komponenten. Jahrestreffen der ProcessNet-Fachgruppe Fluidverfahrenstechnik, Potsdam
Gutperl, S., Dierking, G., Bradtmöller, C., Scholl, S.
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(2020), Beschreibung der Rektifikation viskoser Systeme mit Hydrodynamischen Analogien. Jahrestreffen der ProcessNet-Fachgruppen Fluidverfahrenstechnik, Adsorption und Extraktion, Berchtesgaden
Bolenz, L., Gutperl, S., Toye, D., Scholl, S., Kenig, E. Y. (
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(2020): Simulation und Bewertung eines Anlagenkonzeptes für Trennleistungsmessungen mit nicht-verdampfenden Komponenten. Jahrestreffen der ProcessNet-Fachgruppe Fluidverfahrenstechnik, Berchtesgaden
Gutperl, S., Bolenz, L., Kriese, F., Jasch, K., Kenig, E.Y., Scholl, S.
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(2021), Determination of local fluid dynamic parameters in structured packings through X-ray tomography: overcoming image resolution restrictions. Chemical Engineering Science 229, 115997
Bolenz, L., Fischer, F., Toye, D., Kenig, E. Y.
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(2021), Modelling of a continuous distillation process with finite reflux ratio using the hydrodynamic analogy approach. Chemical Engineering Research and Design 172, 99-108
Bolenz, L., Ehlert, T., Dechert, C., Bertling, R., Kenig, E. Y.
