Among thermal separation methods, solvent extraction is one of the most energy-efficient processes. Basis for high separation efficiency is, besides thermodynamic properties, the high interfacial area; thus, good mixing and dispersion of the two liquid phases are beneficial. The miniaturized stirred-pulsed extraction column is a promising concept for extraction on a laboratory scale, since it combines counter-current flow with high separation performance.
In this contribution, a pulsation system has been investigated, particularly the influence of asymmetric pulsation patterns. It utilizes a rapid upward stroke for a system with a lighter dispersed phase combined with a slow return. The ratio between these stroke times and its influence on flooding, hold-up and separation performance has been investigated for a standard EFCE test system in an extraction measurement cell. The cell has an inner diameter of 15.8 mm and an active extraction height of 136 mm. The hydrodynamic parameters and the extraction performance have been investigated for various frequencies and time ratios of up to 27.57. The results show with more asymmetric pulsation patterns an increasing hold up of the dispersed phase with higher separation performance and thus its potential for process intensification with solvent extraction.