Chemisches Recycling von Automobilkunststoffen mittels Pyrolyse

In the past, the amount of plastic waste steadily increased in Germany. Plastic waste from automotive applications challenges existing mechanical recycling processes due to its material heterogeneity and complexity. However, chemical recycling via pyrolysis has the potential to recycle these plastics, obtain a high value recycled plastic with the quality of virgin material, and reduce the use of primary material. To date, no mass and energy balances are available to assess the performance of the pyrolysis process itself nor the process chain it is embedded in. This study conducted experiments with automotive plastic waste from garages in a pyrolysis screw reactor. The resulting pyrolysisproducts‘ mass and elemental compositions were determined and balanced considering reasonable assumptions. It was shown that about 70 % of the automotive waste plastics‘ inherent carbon was transferred to pyrolysis oil. When considering the entire process chain from waste sorting, pyrolysis of the sorted waste, pyrolysis oil upgrading, and subsequent steam cracking producing ethane, propene, butadiene, and pyrolysis gasoline, a carbon efficiency of approximately 55 % was calculated based on the experimental data, assumptions and data from literature. ... mehrElsewhere, similar experimental results have been found for the pyrolysis of plastic waste from post-shredder treated automotive shredder residue (ASR) from end-of-life vehicles. With a yearly amount of approximately 68,000 tons of ASR in Germany, the potential of chemical recycling via pyrolysis becomes apparent. Future studies should focus on the economic and ecologic assessment and optimized performance of such a process chain. In addition, a better database for pyrolysis oil upgrading and pyrolysis oil steam cracking is needed to yield more accurate results in the assessment of chemical recycling via pyrolysis.