Fireside Corrosion of Austenitic Tube Materials for Advanced USC Boilers

Laboratory corrosion test of Ni-base alloys and austenitic stainless steels was performed in 0.1/0.5% SO2 -5%O2 -10%H2O -15%CO2 –N2 at 650-750°C for 20 h. Mixture of 1.5m/o Na2SO4 -1.5m/o K2SO4 -1m/o Fe2O3 was used as a corrosive. The effect of SO3 concentration on both the onset temperature of melting and the thermal stability of the synthetic coal-ash mixture was investigated by differential scanning calorimetry. Concentration of SO2/SO3 affected the corrosion of steels and alloys at 650°C and 700°C drastically.