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, tr yptophan and phenylalanine. In this method, isotherms were estimated u sing both frontal chromatography and batch equilibrium methods, and ma ss-transfer parameters were estimated using frontal chromatography dat a. SMB experiments were then conducted using the zone flow rates and p ort velocity calculated from a theoretical analysis without considerin g mass-transfer effects (an equilibrium design). The estimated paramet ers were validated with computer simulation and SMB data based on the equilibrium design. A design considering mass-transfer effects (a none quilibrium design) was then obtained from the standing wave analysis a nd tested experimentally. The effluent histories at the extract, raffi nate, and sampling ports agreed with those from computer simulations. A sensitivity analysis shows that accurate isotherms, intraparticle di ffusivities, and bed voidage are important for the SMB design, and the nonequilibrium design is more robust than the equilibrium design, Var ious column configurations were compared in terms of throughput and de sorbent consumption.