Experimental Realization of Single-Column SMB Chromatography with Recycle Lag

In previous work (AIChE J. 2005;51:1641-1653) we demonstrated that the periodic state of the simulated-moving-bed (SMB) process is reproduced by a single-column chromatographic process with a recycle lag of (N-1)×τ time units, where N is the number of columns of the equivalent SMB unit and τ is the switching interval. The operation of this ideal single-column process is formulated by selecting an arbitrary column of the SMB and following its operation over a complete cycle. To implement the recycle lag in practice, a special type of plug-flow tube was proposed. It includes internal elements to make the flow as close as possible to plug flow, and a piston to compensate for the difference between the inlet and outlet flow rates. This is necessary because the recycle lag is not a multiple of the overall cycle duration. The proposed system is a more compact, less expensive, and simpler-to-operate alternative to the SMB. Depending on the efficiency of the recycle tube, it wa s shown that the single-column process can achieve the same purities as the analogous SMB unit while keeping the specific productivity constant.

Here we present an experimental realization of the single-column process with recycle lag that uses a simplified version of the plug-flow device. The experimental proof of concept uses the separation of nucleosides by reverse phase and protein capture by protein-A affinity chromatography as case studies to demonstrate the effectiveness of the proposed chromatography apparatus.