DYNAMIC SIMULATION OF SIMULATED-MOVING-BED CHROMATOGRAPHIC PROCESSES

The Simulated Moving. Bed process is a powerful tool for continuous se paration of multicomponent mixtures in which the components have diffe rent adsorption affinities. It is suitable for a broad range of prepar ative or production scale applications and allows the separation of co mponents with separation factors near unity with high resolution, yiel d and purity. Furthermore, the desorbent rates and the amount of adsor bent required by Simulated Moving Bed processes are much lower than th ose for corresponding batch pocesses. The SMB-process is subject to di fferent parameters specifying plant size, operating conditions and pro cess variables. Precise simulations are therefore necessary for proces s design and evaluation of experimental results. Different rigorous mo dels which describe the chromatographic process in terms of either mov ing beds with steady state countercurrent flow or simulated moving bed s with periodic fluid port switching have been evaluated. The results demonstrate that because of the real periodic flow SMB-processes must be described by rigorous dynamic models with tubular reactor units and fluid port switching. Axial dispersion and mass transfer resistance h ave to be taken into account in order to obtain a good agreement with experimental results. The detailed dynamic model which has been develo ped makes it possible to understand malfunctions of pilot plants, to o ptimise process conditions and to specify startup procedures for SMB-p rocesses.