Separation of a Two-Component Steroid Mixture by Simulated Moving Bed Chromatography

Abstract

A method, combining laboratory scale equilibrium and elution experiments, simplified model based heuristic rules, as well as sophisticated dynamic simulation, was applied to design the separation of a two-component steroid crude mixture in a given laboratory-scale Simulated Moving Bed unit. The adsorption equilibrium isotherms of the pure components were determined by Frontal Analysis method. Langmuir isotherm model was fitted to the measured isotherm data. With the knowledge of these a priori data, elution chromatograms of the pure components were measured for the identification of the hydrodynamic and kinetic parameters in the SMB columns. The process simulation was made by the new method, based on the Direct Computer Mapping of the Generic, Bi-layered Net model. The first estimations of the SMB parameters were derived by means of the Morbidelli’s triangle theory. Starting from a feasible solution, stepwise improvement of the SMB process was carried out by the detailed dynamic simulation, according to a strategy, based on the role of the design parameters. Simultaneously, laboratory-scale SMB experiments were carried out. Good agreement of the measured and calculated data was found. In the next step, the dynamic simulation has been applied for the improvement of the SMB separation (production rate, solvent consumption, recovery). In comparison with simple elution chromatographic separation method, considerable improvement of specific capacity parameters was obtained.