Equipment and method for producing polyhydroxycarboxylic acid

摘要

An equipment for producing polyhydroxycarboxylic acid, includes a ring-opening polymerization apparatus, a liquid phase devolatilizing apparatus, and a drying apparatus, wherein an indirect heat exchanger is connected to a vent gas discharge path of the liquid phase devolatilizing apparatus. The indirect heat exchanger captures a dispersed in-process substance containing hydroxycarboxylic acid cyclic dimers and transfers the substance to the ring-opening polymerization apparatus; a wet condenser and a hot well are connected to a vent gas discharge path of the indirect heat exchanger and that of the drying apparatus, respectively. The wet condenser captures a dispersed in process substance containing the cyclic dimers with the use of a refrigerant containing hydroxycarboxylic acid corresponding to the cyclic dimers and transfers the substance to the hot well; the hot well causes hydrolysis of the cyclic dimers for generation of hydroxycarboxylic acid; the generated hydroxycarboxylic acid is mixed with a refrigerant and the mixture is circulated to the wet condenser; and hydroxycarboxylic acid is highly concentrated via circulation between the wet condenser and the hot well and then discharged.