Mechanical processing of post-consumer plastics for chemical recycling

Markus Bauer

Research output: ThesisDoctoral Thesis


Post-consumer plastics (plastic waste) chemical recycling is driven by their increased mass flows, tightened waste regulations, hydrocarbon resources shortage as well as missing recycling opportunities in order to meet directed targets of increased recycling quotes accommodating efficient resource utilization. Plastic (hydrocarbon) recovery in thermo-chemical conversion units connected to a refinery need adequately prepared feedstock of specified quality, which can be supplied by mechanical processing. Therefore, this thesis characterizes Austrian’s post-consumer plastic (waste) management completed by an European perspective, identifies latter’s state of the art in mechanical processing, evaluates found processes’ theoretical and practical suitability to separate polyolefins (PO-flake) representing the preferred feedstock for chemical recycling, and develops technically feasible and economically attractive process concepts for mechanical PO-flake preparation. Based on data from literature and statistics completed by visits of waste treatment plants and meetings with plant operators, the current post-consumer plastic management is analysed and illustrated in a flow chart completed by a mass balance. Derived from the state of the art in post-consumer plastic as well as minerals mechanical processing, preparation technologies are selected and their PO-flake separation efficiency and behaviour are investigated in pilot scale test runs. Referring to the obtained results specified process concepts of appropriate PO-flake supply (feedstock) for chemical recycling are developed and economically evaluated. The flow chart indicates the ideal points to absorb PO-flake in the field of solid recovered fuels preparation for subsequent combustion comprising more than 70 % of the currently total 550 000 t post-consumer plastic flow in Austria. Slightly more than 20 % of latter are presently material recycled. The two alternatively developed process concepts encompass common used dry processing featuring a cascade of near infrared sensor based sorting units, and, respectively, wet processing featuring centrifugal separator as key technology. A first economic evaluation shows almost identical preparation costs by slight benefits in wet processing and points out input material and residue disposal costs as main influence factors.
Translated title of the contributionMechanische Aufbereitung von Altkunststoffen für das chemische Recycling
Original languageEnglish
  • Flachberger, Helmut, Assessor B (internal)
  • Lehner, Markus, Assessor A (internal)
Publication statusPublished - 2014

Bibliographical note

embargoed until 19-12-2019


  • post-consumer plastics
  • waste processing
  • mechanical processing

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