Improving performance of a five-zone simulated moving bed chromatography for ternary separation by simultaneous use of partial-feeding and partial-closing of the product port in charge of collecting the intermediate-affinity solute molecules

The performance of a five-zone simulated moving bed (SMB) chromatographic process for ternary separation has been improved to a certain extent in previous researches by applying either a partial-feeding (PF) or a partial-closing of the extract-2 port (PCE2) to its operation. To make a further improvement, the strategy of applying both PF and PCE2 simultaneously to the five-zone SMB operation was proposed in this study. The results from both equilibrium-theory analysis and detailed simulation proved that the proposed strategy, which was called PF-PCE2 in this article, had the benefit of a synergy between the individual merits of PF and PCE2 in the five-zone SMB performance. As a consequence, the PF-PCE2 mode could surpass the PF and the PCE2 modes by a wide margin and the standard mode by a much wider margin in the aspects of ternary-separation performance and throughput. For the separation system considered, the PF-PCE2 mode was found to achieve more than 100% improvement, compared to the standard mode. Furthermore, such advantage of the PF-PCE2 over all the other modes was greater as the selectivity between the intermediate-affinity and the highest-affinity components was reduced.

► The operation strategy for improving the five-zone SMB performance was developed.
► This strategy uses both partial-feeding and partial-closing of the extract-2 port.
► There was a large improvement in ternary-separation performance and throughput.
► Such advantage of the strategy was greater as the B–C selectivity was reduced.