(479c) Scale-up Rules for Taylor-Couette Disc Contactor Design

In separation and isolation of value added products from low grade aqueous feed, liquid-liquid extraction has established as a basic unit operation. The Taylor-Couette Disc Contactor (TCDC) has shown suitability for applications in bioseparations due to the simple design of internals. The internals of the TCDC are similar to the design of the Rotating Disc Contactor (RDC) but without stator rings and with increased shaft and disc diameter [1]. The design prevents from formation of hydrodynamic dead zones, crud accumulation and fouling. The increased shaft diameter and the increased disc diameter engender a similar flow pattern compared to banded two-phase flow of Taylor-Couette reactors (TCR), making the TCDC particularly suitable for the processing of biogenic raw materials and harsh operation conditions.

The industrial scale implementation of processes for mass transfer with and without chemical conversion demands reliable scale up rules. Therefore, it is important to elaborate basic experiments for validation of CFD-simulation and for the dimensional analysis [2]. For liquid-liquid phase contactors the reliable prediction of hydrodynamics is a critical issue for the design and scale-up. Since design rules for the prediction of hydrodynamic data for the TCDC are still not available, correlations for the determination of the drop size distribution, the Sauter mean diameter and the dispersed phase hold-up where derived via dimensionless analysis [3]. The correlations have been validated with experimental data from 0.1 and 0.3 m diameter pilot plant scale operation with 1 m active column height. The results of mass transfer experiments have confirmed that the concentration profile and the separation efficiency can simply be modeled with CSTR cascade design [4]. The determination of the residence time distribution has confirmed CSTR cascade operation when exceeding a critical rotational speed. The outcome of CFD-analysis and the experiments provides simple tools for the basic design of the TCDC.

Literature

[1] E. Aksamija, C. Weinländer, R. Sarzio, M. Siebenhofer, Sep. Sci. Technol. 2015, 50 (18), 2844–2852. DOI: 10.1080/01496395.2015.1085406

[2] M. Zlokarnik, Chem. Eng. Technol. 2004, 27 (1), 23–27. DOI: 10.1002/ceat.200403158

[3] A. Grafschafter, M. Siebenhofer, Chemie Ing. Tech. 2017, 4, DOI: 10.1002/cite.201600142

[4] A. Grafschafter, E. Aksamija, M. Siebenhofer, Chem. Eng. Technol. 2016, 39 (11), 2087–2095. DOI: 10.1002/ceat.201600191