Patent ID: 7229558

Claim:
A method for fractionating a solution into at least two fractions by a chromatographic simulated moving bed (SMB) process, comprising: processing a solution in more than one cycle in at least one chromatographic separation loop in a chromatographic simulated moving bed (SMB) system having one or more columns containing chromatographic separation packing material resin beds comprising partial packed beds; said solution comprising a feed solution comprising one or more of the following selected from the group consisting of a feedstock, a recycle liquid comprising a recycle fraction, liquid from a previous chromatographic separation loop, liquid from a subsequent loop, and a solution derived from any of the preceding; forming at least one separation profile comprising a dry solids (DS) profile from said processing of said solution, said separation profile being narrow whereupon a length of chromatographic separation resin bed required for good separation is long in said loop; each cycle comprising a predetermined number of steps in a predetermined order, said steps comprising the following different phases selected from the group consisting of a feeding phase, a circulation phase, an eluting phase, and a recycling phase; at least some of the phases occurring sequentially, consecutively, simultaneously, concurrently, or continuously; said feeding phase comprising feeding said solution into one of the columns and drawing and collecting a product, a residue comprising a residual fraction and/or other fraction from the SMB system; said eluting phase comprising feeding an eluant into one or more columns and drawing and collecting the product, the residue comprising the residual fraction and/or other fraction from the SMB system; said recycling phase comprising recycling said recycle liquid comprising said recycle fraction to at least one of the columns; said circulation phase comprising circulating said solution with said dry solid (DS) profile through said columns of said loop while substantially preventing and without feeding further solution to said columns during said circulation phase and while substantially preventing and without drawing and collecting said products or fractions from the columns or loops of the SMB system during said circulation phase; and said dry solids (DS) profile being circulated with said solution more than once through said columns of said loop during said cycle so that said separation profile passes through said chromatographic separation loop in said SMB system more than once during each cycle using said steps and phases.