Kolonnen für Reaktivextraktion - Populationsbilanzen und Maßstabsvergrößerung
Zusammenfassung der Projektergebnisse
The aim of the project was a multiscale simulation and experimental examination of the reactive extraction in agitated liquid-liquid extraction columns using the EFCE test system Zn2+ / di-(2-ethylhexyl) phosphoric acid (D2EHPA). The usage of computational fluid dynamics (CFD) methods and particle population balance models (PPBM) aimed at a better description of the extraction process in the apparatus. The initial basis was on an experimental examination of the chemical equilibrium constants (bulk and interfacial complexation reaction) in the used solvent and an investigation of the system physical properties. Mass transfer had a significant influence as a change of the component concentrations changed density, viscosity and interfacial tension, which had to be considered in appropriate new correlations. Additionally, experiments in a lab-scale test cell based on a DN32 Kühni extraction column geometry revealed that the existing kernel for droplet breakage probability for physical extraction systems could be used. However, a new unified correlation for the mean number of daughter droplets for different column geometries and physical and reactive extraction systems was developed. The adaption of the coalescence kernel was done by an inverse solution of the droplet population balance model for the above reactive test system. Experimental examinations in an agitated DN32 Kühni extraction column at various operating conditions (rotor speed, throughput, phase ratio, feed concentrations) were performed for model validation. Hydrodynamic tests showed a significant influence of energy input, column loading and phase ratio on drop size distribution, flooding limits and dispersed phase volume fraction (holdup). Mass transfer examinations showed a significant effect of the column loading, phase ratio as well as of the concentrations of the Ion exchanger in the solvent and zinc concentrations in the feed on the mass transfer performance of the extraction column. A simple equilibrium stage-model, taking into account the chemical reactions at the interface and in the organic phase bulk (solute distribution is pH and thus mass transfer dependent), resulted in 2 to 4 theoretical stages per meter being reached by the reactive extraction process. Extending a 1D PPB model for reactive mass transfer it was observed, that for both hydrodynamics (droplet size distribution, Sauter mean diameter, holdup) and mass transfer (zinc ion concentration profiles, pH values) experimental results can be accurately reproduced by the SM-SQMOM model. However, due to the high workload, a coupling of CFD solvers with PPBM, the last aim of the project, could not be achieved in the given three years project time. Nevertheless, it is planned to realize this step in the future. To sum up, mass transfer influences physical properties and solute distribution is thus pH dependent. The proposed SM-SQMOM framework was found to be able to describe column hydrodynamics as well as reactive mass transfer behavior in the agitated type Kühni column.
Projektbezogene Publikationen (Auswahl)
- (2015): Einzeltropfenzerfall bei der Reaktivextraktion. Chemie Ingenieur Technik, 87: 1056
C. Korb und H.-J. Bart
(Siehe online unter https://dx.doi.org/10.1002/cite.201550059) - (2016): Validierung von Tropfenzerfallsmodellen bei der Reaktivextraktion. Chemie Ingenieur Technik, 88: 1294-1295
C. Korb und H.-J. Bart
(Siehe online unter https://dx.doi.org/10.1002/cite.201650308) - (2017): “Solvent extraction in columns in a droplet breakage domain”, Hydrometallurgy, 173: 71-79
C. Korb & H.-J. Bart
(Siehe online unter https://doi.org/10.1016/j.hydromet.2017.08.009) - (2017): “Steady State Population Balance Modeling of Zinc Extraction in a Kühni Liquid-liquid Extraction Column”, Proceedings of the International Solvent Extraction Conference ISEC 2017, Miyazaki, Japan, pp. 63-70
S. Alzyod, C. Korb, M. Attarakih, H.-J. Bart
- Application of He’s methods to the steady-state population balance equation in continuous flow systems, J. Appl. Eng. Sci. Technol. (2017) 3, 71-78
A. Hasseine, I. Bechka, M.M. Attarakih, H.-J. Bart
- On the semi-analytical solution of integro-partial differential equations, Energy Procedia, 139 (2017) 358-366
A. Hasseine, M.M. Attarakih, R. Belarbi, H.-J. Bart
(Siehe online unter https://doi.org/10.1016/j.egypro.2017.11.222) - t (2017): „SQMOM-Modellierung der Hydrodynamik in Kühni-Kolonnen bei der Reaktivextraktion“, Chemie Ingenieur Technik, 89: 1625–1634
C. Korb, S. Alzyod, M. Attarakih, H.-J. Bart
(Siehe online unter https://dx.doi.org/10.1002/cite.201700048) - (2018). CFD Modelling of pulsed sieve plate liquid extraction columns using OPOSPM as a reduced population balance model: coupled hydrodynamic and mass transfer, 28th European Symposium on Computer-Aided Process Engineering (ESCAPE), 10-13 June, 2018, Graz, Austria
Alzyod, S., Attarakih, M., Bart, H.-J.
(Siehe online unter https://doi.org/10.1016/B978-0-444-64235-6.50081-4)
