In many industrial applications, processes are operated discontinuously. Examples are two-phase reactions in stirred tanks or liquid-liquid extractions, where it is often necessary to separate the two phases before further processing. Insufficient methods exist for the design and optimization of this separation step, especially for the scale-up from laboratory to technical scale. In particular, the prediction of the drop size distribution (DSD) in the technical apparatus and, derived from this, the interfacial area in the dispersed state as well as the phase separation behavior has not been possible with certainty to date on the basis of laboratory tests (see Figure 1). This means that optimum apparatus dimensioning and operational management cannot be guaranteed.
In the project, a scale-up methodology is developed specifically for stirred liquid/liquid systems. For this purpose, experimental investigations will be carried out on three different size scales (1 L, 30 L and 500 L). Industrially relevant stock systems (toluene/water, butyl acetate/water and kerosene oil/water) are used, important operating parameters such as dispersed phase fraction, power input, mixing time and stirrer geometry are varied and dispersion and phase separation behavior are analyzed in detail. The model developed based on the results at the 1L scale will be validated and adapted at the other two scales. Thus, a standardized, cross-scale design methodology will ultimately be developed. The basic scheme of the project is shown in Figure 2.