Pseudo-ternary chromatographic separation of dihydroxyacetone from the glycerol oxidation byproducts on a simulated moving bed cascade

The goal of this work was to experimentally separate dihydroxyacetone from glycerol oxidation products ob-tained over a Pt-Bi/AC catalyst, using a cascade of two simulated moving bed (SMB) units. For that, the lab-scale FlexSMB-LSRE (R) unit was used with six columns packed with a strong cationic exchange resin, the DOWEX 50WX-2, in acidic and calcium form. An SMB model was implemented in the gPROMS model builder software and used to design the separation regions, considering kinetic and equilibrium data previously obtained by frontal analysis on a fixed-bed column. Dihydroxyacetone was separated from the organic acids on the SMB packed with the resin in H+ form, being collected in the extract stream with 96.8 % purity on a glycerol-free basis and 87.0 % recovery. This stream was fed to a second unit packed with the resin in Ca2+ form, separating dihydroxyacetone from glycerol with 98.6 % purity and 89.0 % recovery. The SMB cascade showed a produc-tivity of 21.7 kg(DHA) (m(adsorbent)(3).day)(-1), and an eluent consumption of 5.7 m(eluent)(3) kg(DHA)(-1). The SMB model described accurately the experimental data.

Automated summary

The goal of this study was to separate dihydroxyacetone from glycerol oxidation products using a cascade of two simulated moving bed units. The results demonstrated that the SMB cascade with a strong cationic exchange resin efficiently achieved this separation process.