Single-Column Simulated Moving-Bed Process with Recycle Lag: Analysis and Applications

• Published in: Adsorption science & technology Vol. 25; no. 9; pp. 647 - 659
• Main Authors: Araújo, João M.M., Rodrigues, Rui C.R., Silva, Ricardo J.S., Mota, José P.B.
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.11.2007
• Subjects: Chromatography; Columns (process); Computer simulation; Equivalence; Outlets; Ports; Recycled; Switching
• ISSN: 0263-6174; 2048-4038
• DOI: 10.1260/026361707785082369

We report some conceptual and numerical results for a single-column chromatographic process analogous to a simulated moving bed (SMB) with asynchronous port switching. It is shown that the periodic state of the multi-column SMB unit is reproduced by a one-column chromatograph in which the part of its outlet stream that is not recovered as product is recycled back to the column with a lag of (N – 1)τ time units, where N and τ are, respectively, the number of columns and the switching interval of the equivalent SMB unit. This requirement holds true regardless of the port configuration or operational scheme of the analogous multi-column unit. The proposed one-column chromatographic process is a more compact, less expensive and simpler-to-operate alternative to the SMB. By changing the operation of the single-column chromatograph from the classical synchronous port switching to an optimized asynchronous Varicol mode, it is shown that one can easily compensate for a less perfect operation of the plug-flow device that implements the recycle lag.