Characterization and scale-up of transport phenomena in miniaturized, stirred-pulsed extraction columns

• Applicant: Professor Dr.-Ing. Norbert Kockmann
• Subject Area: Chemical and Thermal Process Engineering
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 275162778

Liquid-liquid extraction is one of the most important separation process and gains importance in the treatment of complex mixtures e.g. from biotechnology production processes. The process engineer has a multitude of existing apparatuses, which were not further developed in the last decades. Research activities are focused on fluid dynamics, mass Transfer, and modeling improvements in known and existing equipment. To design an extraction column, process parameters such as dispersion, coalescence, and back mixing are important and have to be determined in extensive pilot plant experiments for each physico-chemical system. The recently developed, miniaturized, and stirred-pulsed extraction column (nominal diameter 15 mm, DN15) has nearly twice as high separation performance compared to conventional stirred columns. However, some details of transport phenomena in the intensified column are not well understood to transfer the high performance to larger columns.This research project aims to gain a better understanding for important phenomena such as residence time, mass transfer, and separation performance in columns with different diameters (DN15, 32 and 50). Beside standardized test systems (EFCE-systems toluene/acetone/water and n-butyl acetate/acetone/water) the columns with different internals will be characterized by separation of complex mixtures (enantiomers and saccharides). With these results intensified extraction columns can be developed and operated on different scales from laboratory to pilot scale. Within the project three major goals should be achieved:i) the improved understanding of transport phenomena in the stirred-pulsed extraction column under various pulsation modes (amplitude, frequency, and phase shift), internals, and stirrer speed, ii) the characterization and modeling of the separation performance under different stirrer and plate geometries and variation of pulsation, stirrer speed, loading, and chemical systems, as well as adjusted residence times within the column with appropriate dispersion and pulsation,iii) the transfer and testing/validation of the results to larger columns with 32 mm inner diameter (miniplant) and 50 mm inner diameter (pilot scale) together with comparison of own data with them of groups in Liège and Kaiserslautern. Superior goal of the project is the improved understanding of the miniaturized, stirred-pulsed extraction column with optimized stirred cell size and geometry together with pulsation and stirrer speed. The transferability of the high separation performance and adjustable, long residence time allow for new applications of liquid-liquid extraction. Hence, new momentum for wider application of extraction columns can be expected as well as new opportunities for existing and installed equipment.

• DFG Programme: Research Grants