Heavy Metals in DFB Steam Gasification of Shredder Residues: Distribution Characteristics of Cr, Fe, Ni, Cu, Zn, As, Cd, and Pb in Bed and Fly Ash Fractions

With end-of-life vehicle (ELV) recycling gaining regulatory and environmental importance, the material utilisation of shredder residue (SR) is becoming increasingly relevant. While steam gasification in dual fluidised bed (DFB) systems is a mature technology for biomass, its potential for processing SR, a heavy metal (HM) containing waste stream, remains largely untapped. This thesis explores at two scales how HMs behave during steam gasification of SR in DFB systems, using both a 100 kW pilot and a 1 MW demonstration plant. Pure SR and SR-wood blends were gasified, with eight target HMs selected for detailed analysis. Solid and gaseous samples revealed distinct HM concentration patterns and a clear volatility ranking. Across all ash fractions, the average concentration of the HMs followed the descending order: Fe > Cu > Ni > Zn > Cr > Pb > As > Cd. The volatility followed the order: Cd > Pb > Cu > As > Zn > Cr > Fe > Ni. The 1 MW system further demonstrated excellent flue gas cleaning with a dust removal efficiency of 99.47 %. These findings offer new insights into HM distribution in waste gasification and support safer, cleaner system design.