Individual Column State and Parameter Estimation in the Simulated Moving Bed Process: an Optimization-based Method

Abstract

The aim of this work is to propose a method for the simultaneous state and parameter estimation of the individual columns in the Simulated Moving Bed chromatographic process based on concentration measurements only in the switched product outlets. The method exploits the fact that the measurements switch from the inlets of the columns to their outlets sequentially. The estimation problem is cast as a dynamic optimization problem where the prediction error of the output profile is minimized. The initial concentrations in the individual columns and the parameters of the columns are treated as degrees of freedom of the optimization problem. As at each outlet the concentrations of one component are very small and therefore are subject to large relative measurement errors for given expected absolute errors of the concentration measurements, measurements for two different points in time, when the extract port and when the raffinate port is at the outlet of the column under consideration are taken into account simultaneously. The effectiveness of the method is demonstrated for the separation of an isopropanolol racemic mixture.