How the physio-chemical properties of char from the pyrolysis of Automotive Shredder Residue (ASR) influences its future uses

Abstract

Pyrolysis of ASR is an emerging technology which may increase circularity in End-of-Life Vehicle (ELV) waste recycling. To scale up from the current pilot scale, physiochemical characterisation of the by-products is required to determine their utilisation. This paper explored how the physiochemical properties of char from different pyrolysis fractions influence secondary uses. ASR was pyrolysed in a pilot-scale unit capable of processing 100 kg h−1 at 900 °C, producing 480 kg of char from which samples were taken for analysis. Three types of pyrolysis char were identified: (i) coarse char (CC) (ii) medium char (MC) and (iii) fine char (FC). Physical (particle size, moisture content and surface analysis) and chemical (calorific value, organic and inorganic elemental analysis) analysis was conducted. Physical and chemical differences were determined between char fractions: CC had the highest particle size (800 µm; mean 353.5 µm) calorific value (14,544 kcal g−1) and metal concentration; the relationship was CC > MC > FC. Organic elemental analysis indicated %C was highest under FC (80.29 %) and %S was highest in CC (1.04 %). Findings from this experiment provided initial insight into the differences in properties of char fractions from ASR pyrolysis. Potential future uses in char commercial markets were evaluated, with upgrading recommendations provided.