Design of simulated moving bed chromatography for amino acid separations

A systematic design method was used to develop a pilot-scale simulated moving bed (SMB) process for the fractionation of two amino acids, tryptophan and phenylalanine. In this method, isotherms were estimated using both frontal chromatography and batch equilibrium methods, and mass-transfer parameters were estimated using frontal chromatography data. SMB experiments were then conducted using the zone flow rates and port velocity calculated from a theoretical analysis without considering mass-transfer effects (an equilibrium design). The estimated parameters were validated with computer simulation and SMB data based on the equilibrium design. A design considering mass-transfer effects (a nonequilibrium design) was then obtained from the standing wave analysis and tested experimentally. The effluent histories at the extract, raffinate, and sampling ports agreed with those from computer simulations. A sensitivity analysis shows that accurate isotherms, intraparticle diffusivities, and bed voidage are important for the SMB design, and the nonequilibrium design is more robust than the equilibrium design, Various column configurations were compared in terms of throughput and desorbent consumption.