Strategy of rearranging the port locations in a three-zone simulated moving bed chromatography for binary separation with linear isotherms.

A three-zone simulated moving bed (SMB) chromatographic process for binary separation, which has been developed previously, was reported to have four ports that are located in the order of desorbent, extract, feed, and raffinate. To make a substantial improvement in the performance of such a three-zone SMB process, the strategy of rearranging the port locations was proposed in this study within a linear isotherm region. The core of the proposed strategy is to transfer the location of the extract port from its classical position (i.e., the position between zones I and II) to the zone III outlet. Simultaneously, the feed and raffinate ports are transferred backwards by one zone. Thus, the order of the proposed port locations follows the order of desorbent, feed, raffinate, and extract. The results from both equilibrium-theory analysis and detailed simulation proved that the proposed strategy was highly effective in improving the product purities or throughput of a three-zone SMB process. Furthermore, it was found that such advantage of the proposed strategy became greater as the difference between the adsorption affinities of the feed components was larger.