Theoretical study of using simulated moving bed chromatography to separate intermediately eluting target compounds

► Center-cut separations based on SMB chromatography. ► Theoretical comparison of several advanced SMB configurations. ► System performance investigated for three different separation problems. ► Influence of large amounts of the impurities was studied. ► Different purity requirements for the target product were investigated. This study deals with the separation of ternary mixtures based on Simulated Moving Bed chromatography to isolate target components with intermediate adsorption strength. To overcome the limitations of conventional SMB systems, which are designed for binary separations and unable to perform center-cut separations, several modifications have been proposed. The purpose of this study was to provide a theoretical comparison of several of advanced SMB configurations capable to separate ternary mixtures. Emphasis is given to those techniques, which have already been used in practice, and to those having potential for future industrial application. SMB cascades connected in series via the extract or raffinate ports of the first unit are analyzed and compared are as well as an integrated 8-zone SMB unit with internal recycle. Additionally, the commercialized pseudo SMB process (JO process) was evaluated. The performance of these modified SMB systems was investigated based on the assumption of linear adsorption isotherms for all three components considering three separation problems characterized by different separation difficulty. Besides the influence of separation factors, the concentrations of the impurities in the feed mixture and the purity requirements for the target product were studied systematically.