Chemical recycling of refrigerator plastic waste by pyrolysis: Yields, product composition, and potential applications
Jonas Vogt, Axel D. Renno, Margret Fuchs, Tim Kurtz, Niklas Netsch, Frank Richter, Grazyna Straczewski, Britta Bergfeldt, Yuleika Carolina Madriz-Diaz, Andréa de Lima Ribeiro, Doreen Ebert, Salar Tavakkol, Simone Raatz, Dieter Stapf
Abstract
Recycling is crucial for sustainable resource management including heterogeneous and contaminated waste fractions such as those derived from composite materials. This study examines the potential application of pyrolysis of a plastic-rich heterogeneous fraction from an advanced mechanical recycling cascade of refrigerators as a representative example of challenging waste streams from Waste Electrical and Electronic Equipment (WEEE). Advanced spectroscopic and chromatographic techniques are used for feedstock and pyrolysis product characterization. A screw reactor on pilot-scale is used to derive pyrolysis mass balances and to evaluate product yields. The organic condensate with a yield of 64 wt% is rich in styrene and lower aromatics. After further upgrading and separation, aromatic base chemicals and other fractions derived from the organic condensate could substitute fossil feedstocks in the chemical industry. The gas fraction yielding 13 wt% could also be suitable for producing basic chemicals after post-processing. Solid residues enriched with fillers and metals which account for 19 wt% of the pyrolysis products offer recycling opportunities although detailed concepts for pollutant removal and filler reuse remain to be validated. This study highlights the potential of pyrolysis for chemically recycling heterogeneous plastic-rich waste by presenting insights into feedstock and pyrolysis product characterization and by indicating sustainable recycling pathways.