A new analytical design approach for operating conditions determination of solvent gradient simulated moving bed (SG-SMB) processes was proposed, which was based on the equilibrium theory. Also a new implemented simulator for SG-SMB was proposed to evaluate the new design approach. The simulator was totally developed in FORTRAN 90/95, assuming a stepwise modeling approach with a lumped mass transfer model between the solid adsorbent and liquid phase. The influence of the solvent modifier was considered by applying the Abel model, which takes into account the effect of modifier volume fraction over the partition coefficient. The optimal conditions determined from the new design approach were compared to the simulation results of a SG-SMB unit applied to the experimental separation of the amino acids phenylalanine and tryptophan. The new design approach, which is based on χ equation and phi-plot analysis, was able to predict a great number of operating conditions for complete separation of such molecules, which was validated by the simulations carried out by the new SG-SMB simulator. Such a SG-SMB simulator provides simulation results with very good agreement fitting the experimental data of the amino acid concentrations both in the extract as well as in the raffinate.
Part of the book: Mass Transfer