A new feeding mode for a simulated moving bed(SMB) is proposed.The outlet stream from zone Ⅱ is collected at regular intervals.The concentration of the solution is increased by dissolving raw materials and then fed to zone Ⅲ as the feed stream during the next collection interval.In this feeding mode

the concentration of the stream fed to zone Ⅲ is identical to that of original feed

while in a conventional SMB

the feed is diluted by mix-ing with the outlet stream of zone Ⅱ before feeding to zone III.The new feeding mode increases the inlet concentra-tion of zone Ⅲ.A modeling investigation shows that higher inlet concentration of zone Ⅲ increases the height of concentration band in SMB

improving the separation performance significantly.In comparison with the traditonal feeding mode

the new feeding mode increases the productivity by 23.52% and decreases the solvent consumption by 22.56%

so as to increase the raffinate and extract concentrations by 53.17% and 20.38%

respectively.The col-lection interval for the outlet stream from zone Ⅱ has no effect on the separation performance after reaching the steady state

so that the collection interval can be increased to make the operation more convenient.