Process and device for simulated moving bed separation with a reduced number of large diameter valves

A device which can separate at least one compound from a mixture comprising said compound by simulated moving bed adsorption, comprising:

• at least one column comprising a plurality of adsorbant beds Ai separated by distributor/extractor plates Pi for sequential supply and extraction of at least two supply fluids:
• a feed F and a desorbant D, and at least two withdrawal fluids:
• a raffinate R and an extract E, Pi being disposed between the bed Ai and the immediately lower bed Ai+1;
• the device also comprising at least one feed network F-Net, a desorbant network D-Net, a raffinate network R-Net and an extract network E-Net, each of said networks being connected to the column via a plurality of lines comprising controlled two-way isolating valves with an opening diameter of α or above, termed network valves, for sequential supply or withdrawal of said supply or withdrawal fluids;
• in which the column is divided, over at least the major part of its height, into a plurality of adjacent superimposed sections Sk, each sector Sk being essentially constituted by 2 successive adsorbant beds Ai, Ai+1 and by the 2 distributor/extractor plates Pi, Pi+1 which are respectively disposed immediately below Ai and Ai+1;
• each of the distributor/extractor plates Pi, Pi+1 of each of the sectors Sk has a single common network for sequential supply and withdrawal of F, D, R, E;
• plates Pi, Pi+1 of each sector Sk are connected together via an external principal bypass line Lk connected to each of plates Pi, Pi+1 of Sk via a connector comprising a single two-way controlled isolating valve which belongs to said plate Pi or Pi+1, termed a plate valve Vi or Vi+1, with an opening diameter which is greater than or equal to the value α for sequential supply or withdrawal of said supply or withdrawal fluids in or from Pi;
• each of said bypass lines Lk comprises at least one controlled means for limiting the flow moving in Lk, which is either installed on the line Lk or bypasses a plate valve Vi or Vi+1 of a plate of Sk;
• in which the bypass line Lk of each of the sectors Sk is connected to each of the networks F-Net, D-Net, R-Net, E-Net via a single line with an internal diameter of α or more comprising a single network valve, respectively VFk, VDk, VRk, VEk, which has an opening diameter of α or more, for sequential supply or withdrawal of fluid corresponding to F, D, R or E to or from the sector Sk under consideration;
• the device also comprising a plurality of external secondary bypass lines Mk, each of lines Mk connecting the 2 adjacent sectors Sk−1 and Sk via 2 connecting points;
• the first connecting point being disposed on the connector connecting the lower plate Pi+1 of the upper sector Sk−1 between Pi+1 and the plate valve Vi−1;
• the second connecting point being disposed on the connector connecting the upper plate Pi of the lower sector Sk between Pi and the plate valve Vi;
• each of the external secondary bypass lines Mk comprising a controlled two-way valve VMk with an internal opening diameter of β or less, in which β≦0.6α.