Experimental Optimizing Control of the Simulated Moving Bed Separation of Tröger’s Base Enantiomers

Abstract

Simulated moving bed (SMB) chromatography has become a well-established technique in the pharmaceutical industry and biotechnology for the separation of enantiomers. However, exploiting the full economic potential of the process is not trivial, and therefore, we developed a “cycle-to-cycle” optimizing controller to facilitate the operation of SMB units close to the economic optimum. The proposed controller only requires the information about the linear adsorption behavior and the average porosity of the columns. This paper presents the different steps required to set up our controller for a given separation problem, namely the separation of Tröger’s Base enantiomers. For the investigated system, the complete adsorption isotherm is available which allows us to carry out detailed simulations and to compare them to the actual experiments. Hence, one can judge how well the simulations can predict both the dynamic and the steady state behavior of the controller at different feed concentrations. The paper demonstrates that the control concept is simple enough to be implemented quickly and reliably for a new separation campaign within three days. Furthermore, the experimental results clearly show that despite process disturbances the controller is able to fulfill the product specifications and to improve the process performance.