Patent ID: 8153754

Claim:
An equipment for producing polyhydroxycarboxylic acid, comprising a ring-opening polymerization apparatus for causing ring-opening polymerization of hydroxycarboxylic acid cyclic dimers, a liquid phase devolatilizing apparatus for devolatilizing of unreacted cyclic dimers or by-products with application of negative pressure while maintaining the generated polyhydroxycarboxylic acid in a melted state, and a drying apparatus for heating solidified polyhydroxycarboxylic acid for drying, 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 the 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 at a concentration of 50% or more 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 the 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.