Fluidized bed gasification of solid recovered fuel in a 500 kWth pilot plant: Impact of temperature profile and bed material on syngas quality

The gasification of plastic-rich waste streams enables the conversion of non-recyclable materials into syngas to produce base chemicals, contributing to carbon circularity. Fluidized bed gasifiers allow the conversion of heterogeneous feedstocks while providing favorable syngas quality. The High-Temperature Winkler® (HTW®) process, combining a bubbling fluidized bed with a post-gasification zone (PGZ), is established for coal and biomass, but its application to plastic-rich waste streams remains challenging due to the high volatile content. This study demonstrates the technical feasibility of HTW® autothermal gasification of pelletized solid recovered fuel (SRF) during 155 h of operation in a 500 kW th pilot plant. The influence of the axial temperature profile (λ: 0.31–0.37; bed: 650–715 °C; PGZ: up to 840 °C) and the addition of olivine as external bed material on syngas quality and hydrocarbon formation was analyzed. The study identifies the PGZ as the key reaction zone governing hydrocarbon conversion and syngas upgrading. Optimized conditions yielded a syngas composition (dry) of 20 vol% H₂, 16 vol% CO, and 8 vol% CH₄. The lowest hydrocarbon loads obtained were 44 g/kg feed aromatic hydrocarbons and 2.5 g/kg feed gravimetric tar. The addition of olivine altered the temperature profile but did not improve performance.