Method of purification of post-production condensates from polyester polyol production

Abstract Nowadays, the topics of closed-loop and eco-design are raised very often, especially in the chemical industry. To combine development with these trends, Purinova Sp. z o.o. has focused on pursuing the closed-loop use of post-production condensate from polyester polyols production. To this end, purification and distillation processes have been adapted, both at the laboratory and production scale, to receive treated condensate with decreased Chemical Oxygen Demand (COD) index. The method involves connected purification of production condensate by returning condensate to the top of the distillation column during polycondensation and two stages distillation system afterwards. The method allows for decreasing COD index and contents of diethylene glycol and 1,4-dioxane. The resulting technology has consequently allowed the use of tailored distillation in the purification of post-production condensates in the production of polyester polyols. Furthermore, the quality of the condensate obtained allowed it to be used in the closed loop of the production plant.