Chemical Recycling of WEEE Plastics—Production of High Purity Monocyclic Aromatic Chemicals

• Published in: Processes 2021-03, Vol.9 (3), p.530
• Main Authors: Rieger, Tobias, Oey, Jessen C., Palchyk, Volodymyr, Hofmann, Alexander, Franke, Matthias, Hornung, Andreas
• Format: Article
• Language: English
• Subjects: Aromatic compounds; Benzene; Chemicals; Chlorine; Composite materials; Conversion; Electronic equipment; Electronic waste; Ethylbenzene; Flame retardants; Fluidized bed reactors; Fractional distillation; Gas chromatography; Heat exchangers; Investigations; Mass spectrometry; Mass spectroscopy; Plastics; Purity; Pyrolysis; Raw materials; Recycling; Residues; Styrene; Styrenes; Toluene; X-ray fluorescence; Xylene
• ISSN: 2227-9717; 2227-9717
• DOI: 10.3390/pr9030530

More than 200 kg real waste electrical and electronic equipment (WEEE) shredder residues from a German dismantling plant were treated at 650 °C in a demonstration scale thermochemical conversion plant. The focus within this work was the generation, purification, and analysis of pyrolysis oil. Subsequent filtration and fractional distillation were combined to yield basic chemicals in high purity. By means of fractional distillation, pure monocyclic aromatic fractions containing benzene, toluene, ethylbenzene, and xylene (BTEX aromatics) as well as styrene and α-methyl styrene were isolated for chemical recycling. Mass balances were determined, and gas chromatography–mass spectrometry (GC-MS) as well as energy dispersive X-ray fluorescence (EDXRF) measurements provided data on the purity and halogen content of each fraction. This work shows that thermochemical conversion and the subsequent refining by fractional distillation is capable of recycling WEEE shredder residues, producing pure BTEX and other monocyclic aromatic fractions. A significant decrease of halogen content (up to 99%) was achieved with the applied methods.