Verfahren und Vorrichtung zur Rückgewinnung von Dicarbonsäuren und Diolen aus Polyesterabfällen, insbesondere aus Polyethylenterephthalat(PET)-Abfällen beliebigen Polymerisationsgrades

摘要

A process for recovering dicarboxylic acids and diols from polyester waste, especially polyethylene terephthalate (PET) waste, comprises the liquid phase de-esterification of the PET in a first depolymerisation reactor to split the PET into shorter polymer chains and the subjecting these glycolised chains to an ester cleavage step in a second depolymerisation reactor. Dwell time in the first reactor is controlled by the progress of the reaction, determined by eg. a detector (4) recording the mean glycolised short PET chain length. Dwell time in the second reactor is also controlled by the progress of the reaction, determined by eg. using a detector (13) to measure contamination. The apparatus used for carrying out the process is also claimed.