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Abstract

Simulated Moving Bed (SMB) chromatography is a well-established process that can be applied at widely different scales for adsorption based separations. There is an increasing interest in isolating a target component out of a multicomponent feed mixture. Since the conventional 4-zone SMB system is unable to produce a pure product stream if the desired component is neither the strongest nor the weakest adsorbable component, various modifications of SMB systems have been proposed [e.g. 1, 2]. In this work a separation of a ternary mixture based on simulated moving bed technology and the assumption of linear adsorption isotherms is investigated. Two coupled 4-zone SMB units connected in series by extract or raffinate port operated in semi-continuous and continuous mode are analyzed and subsequently compared to an integrated 8-zone SMB unit with internal recycle. As the major aspect of this research, the influence of the separation factors and the excess of the weaker/stronger adsorbed component in the feed mixture on the separation performance are studied. Separation under reduced purity requirements for the target component is also analyzed. Finally, the potential of modulating the solvent strength during the process (gradient operation) is investigated. To describe the performance of considered arrangements a standard dynamic model was applied. Different approaches for optimization will be compared. [1] G. Paredes, S. Abel, M. Mazzotti, M. Morbidelli, J. Stadler, Ind.Eng.Chem.Res. 43 (2004) 6157 [2] B.J. Hritzko, Y. Xie, R.J. Wooley, N.L. Wang, AIChE J. 48 (2002) 2769