SMB(simulated moving bed) is a kind of mass transfer equipment that uses the adsorption principle to conduct liquid separation operation. By means of countercurrent continuous operation, the position of material inlet and outlet of the fixed bed adsorption module can be changed to produce the effect of continuous adverse movement of adsorbent and continuous forward movement of material.The production capacity and separation efficiency of the simulated moving bed are higher than the fixed adsorption bed, which can avoid the problems of the moving bed adsorbent wear, dust blocking equipment or pipelines etc. Therefore, this technology has been widely concerned and applied in recent years.