Monomer production system and monomer production method

A monomer production system comprising:

• a dissolving unit configured to store a polyester solution in which polyester is dissolved in a carboxylic acid-derived monomer;
• a first reaction unit into which the polyester solution and a reaction solvent to react with the polyester are introduced to bring the polyester solution into contact with the reaction solvent to depolymerize the polyester in the polyester solution and extract a first depolymerized polyester containing the depolymerized polyester into the reaction solvent;
• a second reaction unit into which the reaction solvent with the extracted first depolymerized polyester is introduced to cause the first depolymerized polyester to further react with the reaction solvent to further depolymerize the first depolymerized polyester and generate a second depolymerized polyester that is the further depolymerized first depolymerized polyester;
• a separation unit into which the reaction solvent with the dissolved second depolymerized polyester is introduced to separate the reaction solvent with the dissolved second depolymerized polyester into the reaction solvent, the carboxylic acid-derived monomer contained in the second depolymerized polyester, an alcohol component monomer contained in the second depolymerized polyester, and residual substances that are components other than the reaction solvent, the carboxylic acid-derived monomer, and the alcohol component monomer, the residual substances containing oligomers;
• and
• inlet pipes configured to introduce the carboxylic acid-derived monomer and the residual substances into the dissolving unit.