System and process for recovering products using simulated-moving-bed adsorption

A process for the separation of components in a feed stream comprising at least one preferentially adsorbed component and at least one non-preferentially adsorbed component by simulated countercurrent adsorptive separation comprising:

• introducing a feed stream into a port of a multi-bed adsorptive separation chamber comprising a plurality of ports with corresponding transfer lines via one transfer line in fluid communication with the port;
• and
• withdrawing an extract stream from the adsorptive separation chamber through the one transfer line, wherein the extract stream has a higher concentration of the preferentially adsorbed component than the feed stream and a lower concentration of the non-preferentially adsorbed component than the feed stream;
• introducing a desorbent stream into the port of the adsorptive separation chamber;
• withdrawing an extract stream from the adsorptive separation chamber, wherein a portion of each stream introduced and withdrawn through the transfer line remains in the transfer line as residual fluid;
• and
• flushing the transfer line at first flow rate for a first portion of a step-time interval during which the transfer line is not occupied by one of the feed stream, the extract stream, the desorbent stream, and the raffinate stream;
• and
• flushing the intermediate transfer line at as second different flow rate for a second portion of the step-time interval so that a greater volume of fluid is flushed from the transfer line during one portion of the step-time interval than the other portion of the step-time interval.