Analysis of reactor–separator processes for polymeric and oligomeric degradation products with controlled molar mass distributions

Abstract

Integration of reaction and separation is attractive in production of biobased oligomers and short polymers from polysaccharides and proteins via catalytic degradation. The challenge lies in controlling the molar mass distribution. Theoretical analysis for process integration is performed for conventional CSTR, a multifunctional reactor, and reactor-separator-recycle processes. Closed-form solutions for the mass balance equations are obtained for coupled serial-parallel first-order reactions. The influence of the separators’ cut-off range and sharpness on the feasible operating parameter range and process performance is visualized. It is found that a membrane reactor may be less productive than a CSTR if total concentration is limited. An additional separator to recycle the solvent significantly improves purity and productivity. Solvent recycling decouples the feed rate and the residence time of the product molecules. To maximize purity and productivity, no product molecules should be retained in the reactor whereas the recycled solvent can be impure.