DBLLD

DBLLD (drop behavior of liquid-liquid dispersions), formerly ERICAA (Energie- und Ressourceneinsparung durch Innovative und CFD-basierte Auslegung von Flüssig/Flüssig-Schwerkraft-Abscheidern, Saving Energy and Resources by Innovative CFD-based Design of Liquid-Liquid Gravity Settlers) is a joint project with a variety of partners from industry and academia, funded by the German Federal Ministry for Economic Affairs and Energy. This project has been extended after ERICAA to understand more details of the drop behavior in liquid-liquid dispersions.

Partners

• Bayer Technology Services GmbH
• Franken Filtertechnik KG (project coordination)
• SOPAT GmbH
• Normag GmbH
• LANXESS Deutschland GmbH
• Raschig GmbH
• TU Berlin, Chemical & Process Engineering
• TU Kaiserslautern, Separation Science and Technology
• INEOS Phenol GmbH
• Linde AG
• Covestro AG

Starting point of the project is the observation that in large gravity settlers the two-phase flow may show significant backmixing, which is detrimental for the phase separation. On the other hand, smaller settlers can be well described by appropriate models based on standardized settling cells, which allow characterization of the material-system specific coalescence behavior.

Goals

• to define and validate an optimized standardized lab-scale settling experiment including appropriate evaluation to evaluate the coalescence behavior
• to apply CFD simulation for modelling the large-scale flows in large technical settlers, where the sedimentation of the drops and their coalescence is accounted for
• to use a DN150 pilot-plant settler for characterization of the settling behavior

Special focus will be on the drop-size distribution, which today is frequently neglected. Especially for wide drop-size distributions, a significant fraction of droplet phase may be carried out of the settler due to the small droplets lagging behind. This remaining drop-phase fractzion is a critical design parameter.

Our tasks in this project are the definition and validation of the standardized lab-scale settling cell including the detailed evaluation, the definition of appropriate coalescence models for use in the CFD simulations, and various work packages relating to characterizing the real systems used.

This project has been extended after ERICAA to understand more details of the drop behavior in liquid-liquid dispersions.

Publications

N. Kopriwa, A. Pfennig: Characterization of Coalescence in Extraction Equipment Based on Lab-Scale Experiments. Solvent Extr. Ion Exc. 34(7) (2016) 622-642. 

M. Henschke, L.H. Schlieper, A. Pfennig: Determination of a coalescence parameter from batch-settling experiments. Chem. Eng. J. 85 (2002) 369–378.

L. Schlieper, M. Chatterjee, M. Henschke, A. Pfennig: Liquid-Liquid Phase Separation in Gravity Settler with Inclined Plates. AIChE J. 50(4) (2004) 802-811.