Patent ID: 8821732

Claim:
A device for separating a feed F by simulated moving bed adsorption, said device comprising: a plurality of elementary zones Z i in series operating in a closed loop, each of said zones comprising, between two successive points for sequential injection of feed or eluent or for sequential extraction of extract or raffinate, a unique bed L i of adsorbant solid with volume VA i and a volume for movement in the loop which is free of adsorbant, termed the non-selective free volume V i , in which at least 3 zones Z i each comprise a single bed of adsorbant with a volume which is substantially identical to VA, and a non-selective free volume which is substantially identical to V, said zones being termed ordinary elementary zones; the device also comprising, from among zones Z i , at least one elementary zone Z 0 termed the particular elementary zone, which is different from the ordinary elementary zones, Z 0 comprising a non-selective free volume V 0 which is greater than V and a unique bed L 0 of adsorbant solid with volume VA 0 which is less than VA; in which the same adsorbant mean solid S is used for the beds of said ordinary elementary zones and an adsorbant mean solid S 0 , which is different from S, is used for the bed of said particular elementary zone Z 0 , the volume adsorption capacity C 0 of S 0 being more than the volume adsorption capacity C of the solid S, such that the overall adsorption capacity, C 0 ×VA 0 , of said particular elementary zone Z 0 is closer to the overall adsorption capacity, C×VA, of each of said ordinary elementary zones than the overall adsorption capacity of Z 0 calculated as if the adsorbant solid of bed L 0 of Z 0 were the solid S, thereby satisfying the following relationship: | C×VA−C 0 ×VA 0 ≦C×VA−C×VA 0 .