Ineos Styrolution Group Gmbh

Frank Neuner

Norbert Niessner

Achim Schmidt-Rodenkirchen

Bianca Wilhelmus

Konstantin Mierdel

The invention relates to a method for producing styrene monomers by the depolymerisation of polystyrene in the presence of foreign polymers, such as polyolefins. Said method comprises the following steps: a) introducing a polymer composition (A) containing: I) 10 to 99.5% by weight, based on the polymer composition (A), of polystyrene (I); and II) 0.1 to 89.9% by weight of polyolefin (II); and/or III) 0.1 to 4.9% by weight of acrylonitrile-based polymer (III); and/or IV) 0.1 to 4.9% by weight of polyester (IV), into the reaction zone (R) of a pyrolysis reactor (P); b) thermal cracking the polystyrene contained in the polymer composition (A) in the reaction zone (R) of the pyrolysis reactor (P) at a temperature of between 400-1000° C., c) removing the product mixture (G) obtained from the reaction zone (R), d) cooling of the product mixture (G), and e) separating the styrene monomers from the further components.

Method for the depolymerisation of polystyrene in the presence of foreign polymers

The invention relates to a process for the preparation of styrene monomers by depolymerising polystyrene, to a device for carrying out the process and to the use of a fluidised bed reactor for the depolymerisation of polystyrene. Said process comprising the following steps: a) feeding a polymer composition (A) containing 60 to 99.9 wt. polystyrene, based on the total weight of the polymer composition (A), into the reaction zone (R) of a pyrolysis reactor (P); b) thermally cracking the polystyrene contained in the polymer composition (A) in the reaction zone (R) of the pyrolysis reactor (P) at a temperature of between 400° C. to 1000° C. to obtain a product mixture (G) containing styrene monomers and other components; c) removing the product mixture (G) obtained in step b) from the reaction zone (R) of the pyrolysis reactor (P); d) cooling the product mixture (G) removed in step c) to obtain a condensed product mixture (K) containing styrene monomers and further components; and e) separating the styrene monomers from the further components of the condensed product mixture (K) obtained in step d), wherein the average residence time (Z) of the polymer composition (A) in the reaction zone (R) of the pyrolysis reactor (P) is from 0.01 sec to 10 sec.

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Bayreuth, Germany

Frank Neuner