One of the approaches to improve the performance of SMB is using the periodic modulation of operating parameters. Partial-feed operation is also one of these approaches. “Partial-feed” concept was suggested by Zang and Wankat (2002) and compared with total-feed operations. “Partial-feed” means that the feed is introduced into the SMB system during part of a switching period.

In this work, “partial-feed” operation at the low selectivity condition was rigorously studied for the four-zone SMB with one or two column per zone. In the case of SMB with one column per zone, all the performance parameters become better as the feed length decreases even in the extremely low selectivity. The other hand, when the “partial-feed” operation is applied to the four-zone SMB with two columns per zone, the “partial-feed” worsens the performance of SMB in view point of all the performance parameters in low selectivity. However, in high selectivity condition, the “partial-feed” enhanced the purities. Even in the condition of low selectivity, optionally one component purity or recovery can be improved by controlling the feed time while the eluent consumption is worse than the results of “total-feed” operation for all the operating range.

In addition, the “partial-feed” operation was successfully improved the performance of SMB by applying to the “partial-discard” as the “partial-discard with partial-feed”.