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5700172 
Journal Article 
Recycling of mixed plastics by pyrolysis in a fluidised bed 
Kaminsky, W; Schmidt, H; Simon, CM 
2000 
1 
Macromolecular Symposia
ISSN: 1022-1360
EISSN: 1521-3900 
152 
1 
191-199 
English 
WOS:000087518000018 
Mixtures of plastics and a plastic light fraction from DSD, Germany were used as feedstocks. The fluidised bed was heated indirectly and fluidised by pyrolysis gas, nitrogen or preheated steam. By a pyrolysis temperature of 510 degrees C up to 90 wt % of the feedstock was obtained as oil or waxy products. The content of aromatics is low and lies between 0.1 and 0.3 wt %. The liquid product can be used as feedstock for a steam cracker and as a substitute for naphtha. By a higher pyrolysis temperature of 690 to 735 degrees C and pyrolysis gas as fluidising gas the experiment yielded about 40 wt % of an oil which consists mainly of benzene, toluene and xylene (BTX-aromatics). The organic chlorine content in the low boiling oil is less than 10 ppm and therefore useful in the petrochemistry.

The present report describes the pyrolysis of a light fraction (LF) of mixed plastic waste (MPW) in a fluidised bed lab scale reactor. The main components of the waste were polyethylene (PE) and polypropylene (PP) with a small amount of polystyrene (PS) (<4 %). The aim of the investigation was to yield the monomers ethene and propene. Therefore steam was used to fluidise the bed. Nine test runs were made with reactor temperatures between 545 and 750 degrees C and residence times from 2.3 to 3.6 s. To compare experiments which are different in both parameters temperature and residence time, the crack severity was calculated for each experiment. The crack severity shows the same influence on the product distribution as it does on naphtha in technical steam crackers.

At temperatures between 700 and 750 degrees C high amounts of olefins were obtained. There are 21-29 wt % ethene, 16-21 wt % propene and 5.6-6.6 wt % butadiene. These results are similar to the products of naphtha cracked in steam crackers. 
7th European Polymer Federation Symposium on Polymeric Materials: Polymers Friendly for the Environment 
Szczecin, Poland 
September 20-24, 1998