Design and online optimization of a new continuous chromatographic separation process for ‘center-cut’ separations

• Applicant: Ju Weon Lee, Ph.D.
• Subject Area: Chemical and Thermal Process Engineering
• Term: from 2020 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 441831362

In fine chemical and pharmaceutical industries, chromatographic separation techniques are widely used to isolate valuable target components that elute in between impurities from complex mixtures, which is known as a ‘center-cut’ separation problem. It is well known that continuous separation processes, such as simulated moving bed (SMB) chromatography, are efficient and cost effective compared to batch or semi-continuous chromatographic separation processes. However, it is still challenging to design and optimize a suitable continuous chromatographic process due to operational and structural complexity, in particular regarding ’center-cut’ separations. In this proposal, the applicant introduces a new SMB process concept that can isolate a desired target component and thus solve the ‘center-cut’ separation problem. For developing the idea in preliminary investigations, the applicant analyzed the operational similarity between SMB chromatography and fractional distillation considering especially the dividing wall (DW) distillation process, which is nowadays well-established and widely-used for multi-component fractional distillation. Based on the promising results of these preliminary investigations, a novel continuous SMB process concept is suggested for performing ‘center-cut’ separations with SMB. As the DW distillation can save energy compared to the equivalent sequential distillation process, the new suggested “Double 6-zone SMB” can reduce solvent consumption compared to the earlier suggested alternative sequential SMB cascade. The promising predictions of the performance of the new process described in this proposal were made exploiting a simplified theoretical approach based on the equilibrium model of chromatography assuming linear adsorption isotherms. In pursuance of this project, the applicant aims for acquiring both theoretical and experimental new insights regarding the potential of the process. In detailed theoretical research a new short-cut design method will be developed, which is applicable to treat more realistic competitive non-linear isotherms. An online optimizer based on a rigorous process model will be developed for the dynamic optimization of a pilot-scale SMB process in collaboration with Prof. Achim Kienle at the host institution, Otto-von-Guericke University. In the experimental research, “Double 6-zone SMB” will be implemented into an available pilot-scale SMB unit provided by the cooperation partner, Prof. Andreas Seidel-Morgenstern, Max-Planck-Institute Magdeburg. The developed design and optimization method will be experimentally validated to separate mixtures of cycloketones considered as model solutes.

• DFG Programme: Research Grants