Process Intensification of the Synthesis of Biomass-Derived Renewable Polyesters: Reactive Distillation and Divided Wall Column Polyesterification

We present the reactor simulation, multiobjective optimization, and the process intensification of biomass-derived polyesters: poly(1,5 pentylene 2,5-furan dicarboxylate) (PPeF), poly(1,5-pentylene 2,5-furandicarboxylate-co-1,5-pentylene succinate) (PPeFS), and poly(1,5-pentylene succinate) (PPeS). A plug flow reactor (PFR) was the first configuration considered, and the intensification of the polyesterification was done considering a reactive distillation (RD) and a divided wall column (DW) configuration. The process simulations along with the ε-constraint optimization methodology and sensitivity analyses were implemented in Aspen Plus for a step-growth polymerization mechanism, where the segment concentration profiles, number molecular weight (Mn), and degree of polymerization (DPN) were estimated for each polyester, using poly(ethylene terephthalate) (PET) as the reference polyester. The Mn values obtained were in the range of 2300–4800 Da, suitable for coil coating applications, and the optimum operation temperatures were between 205 and 230 °C. The configurations were compared in terms of common sustainability indicators: CO2 emissions (GWP), energy intensity (RSEI), and mass efficiency (ME). It was determined that the GWP for PPeF was the lowest of all the polymers, and approximately 50% lower than that for PET in the PFR synthesis. The synthesis of PPeF represented the lowest net energy consumption, followed by PPeFS 30/70, regardless of the reactor configuration. In all cases, reactive distillation was the most energy efficient configuration, as the RSEI indicator was below those corresponding to PFR and divided wall, which proves the effect of the intensification in an industrial polyesterification reaction.