High temperature corrosion of oxide bonded silicon carbide refractory lining in WtE facilities

This study investigated oxide bonded SiC refractories lining failure in Waste-to-Energy boilers taking into account SiC material description and operating conditions. SiC tiles located at different elevations are instrumented with thermocouples. Hot side temperatures range from 900 °C to 700 °C depending on flue gas temperature at corresponding elevations. On-site tile observation showed: (i) wear by slag phases, (ii) swelling and cracks of tiles and (iii) fractures. Post-mortem analysis after several thousand hours of operation revealed three main corrosion mechanisms: molten salt/slag attack (Na, K, Ca sulphate phases), salt condensation inducing new phase formation (SiO2–CaSO4–K2SO4) and SiC oxidation. The relative contributions of chemical degradation mechanisms are discussed and tile deformation is related to thermo-chemo-mechanical coupled effect.