Recycling of plastic-rich streams from waste electrical and electronic equipment (WEEE) sorting plants: An in-depth study of pyrolysis potential through product characterization and life cycle assessment (LCA)

Abstract

Thermochemical recycling is emerging as a viable alternative for the recycling of complex plastic waste streams, such as those originated in waste electrical and electronic equipment (WEEE) sorting facilities. In this work, three different WEEE plastic-rich samples are subjected to pyrolysis and the resulting products are thoroughly analyzed to assess their potential industrial utilization. The pyrolysis processes are conducted in a 3 L non-stirred tank reactor at a heating rate of 15 °C/min, reaching a final temperature of 500 °C with a dwell time of 30 min, using 1 L/min of N₂ as carrier gas. The pyrolysis products are characterized and evaluated for their potential applications, including petrochemical feedstock, refuse derived fuel (RDF), and solid adsorbent. The results indicate that pyrolysis liquids can be used as RDF in cement kilns, provided the halogen content is below acceptance limits. The gases produced could be used as refinery gases after pollutant removal. Additionally, the solid fraction casts promising results in preliminary tests as a drug adsorbent in water, suggesting a new and very interesting path of research. Life cycle assessment (LCA) shows that the pyrolysis of sample C, which has the worst chemical properties, gives the lowest environmental impact, since the solid fraction from this sample is the most effective adsorbent, achieving almost 100 % removal efficiency for the tested drugs. The findings suggest that pyrolysis of plastic-rich streams should not always be focused on the oil production, as it can yield other valuable products.