| 摘要 |
<p>Disclosed is a method for producing polyesters by polymerizing terephthalic acid and/or its ester-forming derivative, and a glycol and/or its ester-forming derivative in a plant comprising an esterification device and a polycondensation device in series, while partly or wholly recycling the distillate from the esterification device and/or the polycondensation device that consists essentially of a glycol and/or its ester-forming derivative. The method comprises a step of continuously or intermittently measuring the content of at least one of water, the glycol and its ester-forming derivative in the distillate to be recycled, determining the amounts of the raw materials to be fed to the intended reaction device, on the basis of the data thus measured, and feeding the thus-determined amounts of the raw materials to the reaction device; or comprises a step of storing the distillate, prior to being recycled for the starting material, in a storing tank that has a capacity corresponding to the amount of the glycol and/or its ester-forming derivative to be fed to the esterification device for a period of 10 hours or more.</p> |
