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

摘要

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 (SiO_2-CaSO_4-K_2SO_4) and SiC oxidation. The relative contributions of chemical degradation mechanisms are discussed and tile deformation is related to thermo-chemo-mechanical coupled effect.