Simplified design of steady-state recycling chromatography under ideal and nonideal conditions

In a recent contribution a design method for steady-state recycling chromatography in the so-called mixed-recycle mode (MR-SSR) has been proposed by Sainio and Kaspereit (2009). The method holds under ideal, dispersion-free conditions for chromatographic systems with competitive Langmuir adsorption isotherms. Here this approach is extended to practically relevant nonideal conditions with significant dispersive effects and convex-upward adsorption isotherms in general. The developed shortcut design method allows designing MR-SSR processes based on a simple procedure applied to a single conventional chromatogram. The method is validated experimentally for the separation of two cycloketones on a polymeric stationary phase. The performance of the MR-SSR process is compared to batch chromatography by means of a simulation study.

► The key task in the design of steady-state recycling chromatography processes is choosing the cut times that define the different fractions.
► We suggest a short-cut method for estimating these times in the case of convex-upward isotherms.
► A single reference chromatogram is required but no isotherm data or model.
► The validity of the developed approach was investigated experimentally and by simulations.
► The so-called mixed recycle SSR mode was found to outperform batch chromatography.