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

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The goal of this work was to experimentally separate dihydroxyacetone from glycerol oxidation products obtained over a Pt-Bi/AC catalyst, using a cascade of two simulated moving bed (SMB) units. For that, the lab-scale FlexSMB-LSRE® 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 productivity of 21.7 kgDHA (m3adsorbent·day)−1, and an eluent consumption of 5.7 m3eluent kgDHA−1. The SMB model described accurately the experimental data.