Design of a Five-Zone Simulating Moving Bed Using the Safety Margin Method

Abstract

Modification of the classical simulating moving bed (SMB) process, to separate multicomponent feed mixture effectively, is one of the major issue in many bio-separation and biotechnology problems. Several concepts exploiting more than one SMB unit (connected in series, parallel or in both configurations) have proposed in the literature for the separation of ternary and quaternary feed mixtures. Usually such modification results in significant increase of capital and operational cost, due to the operation of more SMB units for the desired multicomponent separation, which makes the process more complicated. Five-zone simulating moving bed is a modified form of four-zone SMB (only effective for binary separation), designed for ternary separation. The five-zone SMB reported in literature separates the intermediate affinity stream with a lower purity value than that of low affinity and high affinity streams. The objective of the current work is to separate a ternary amino acid mixture with effectively high product purity values. In addition, the effect of zone safety factor (β₂, β₃ and β₄) values on the separation performance of five-zone SMB (designed with safety margin method) is also illustrated. The operating conditions both at fixed feed flow rate and fixed zone-I flow rate were calculated by using triangle theory. Moreover, the simulation study was conducted with Aspen Chromatography simulator. Finally, the column profile study of the five-zone SMB was made to investigate how zone safety factor (β₂, β₃ and β₄) values affect the solute wave dynamics and separation performance.