Industrial & Engineering Chemistry Research, Vol.56, No.11, 3017-3032, 2017
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 epsilon-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 (M-n), and degree of polymerization (DPN) were estimated for each polyester, using poly(ethylene terephthalate) (PET) as the reference polyester. The M-n 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 degrees C. The configurations were compared in terms of common sustainability indicators: CO2 emissions (GWP), energy intensity (R-SEI), 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 R-SEI indicator was below those corresponding, to PFR and divided wall, which proves the effect of the intensification in an industrial polyesterification reaction.