Gasification-flameless and N₂O-assisted combustion for ultra-low PCDD/F emissions from chlorine-rich solid recovered fuel

• GFCM/NACM increase chlorine tolerance in SRF for PCDD/F control. • GFCM improves the CO/NOx trade-off but increases fine particle emissions. • N₂O-enhanced GFCM cuts PCDD/F mass and lowering toxicity. • Advanced combustion/APCS enable Cl-SRF use with emission control. • GFCM/NACM enhances SRF energy recovery by reducing heat loss. Chlorine‑rich solid recovered fuel (Cl‑SRF) poses persistent risks of polychlorinated dibenzo‑p‑dioxin and dibenzofuran (PCDD/F) formation and a high operational burden on air‑pollution control systems (APCS). Meanwhile, the valorization of nitrous oxide (N₂O) in waste‑to‑energy systems remains underexplored, creating a gap between emission control needs and oxidant utilization. This study pioneers a "waste-treats-waste" strategy by integrating gasification-flameless combustion (GFCM) with N₂O-assisted combustion (NACM) to simultaneously suppress PCDD/Fs and utilize residual N₂O. Pilot‑scale tests with chlorine‑rich SRF (1.58 wt%) show that NACM achieves a 95.7 % reduction in total PCDD/F mass concentration (to 15.3 ng/Nm³) and lowers stack toxicity to 0.044 ng WHO‑TEQ/Nm³, well below stringent limits. GFCM reduced conventional CO and NOx emissions by 36 % and 66 %, respectively, versus diffusion combustion (DCM), while NACM maintains NOx 52 % below DCM and improves thermal homogeneity in the primary chamber. Perfectly stirred reactor kinetic modeling indicates that reactive oxygen radicals from N₂O decomposition inhibit chlorinated precursors with a negligible NOx penalty. Ultimately, this approach enables the safe valorization of high-chlorine waste fuels, demonstrating a robust pathway for a circular economy by converting problematic waste streams into sustainable energy.