Chlorine Attack of Carbon Steel Between 350 and 500 °C and Its Importance Regarding Corrosion in Waste Incineration

Corrosion in waste to energy (WTE) plants is an extremely interesting issue, involving complex atmosphere and deposit interactions. In this work, the influence of the complex WTE atmosphere and its various constituents was simulated between 350 and 500 degrees C in order to obtain a better understanding of the corrosion mechanisms occurring in such atmospheres. For this purpose, the typical flue gas mixture of WTE plants was reduced to simpler systems, and the impact of gaseous species typically contained in WTE plants atmospheres on the corrosion rate of the carbon steel 16Mo3 was investigated. Four different atmospheres were used in this work: "full" WTE atmosphere 0.1%HCl + 0.01%SO2 + 8%O-2 + 17H(2)O + 10%CO2 + N-2, 0.1%HCl + 15 ppmO(2) + 0.01%SO2 + N-2, 0.1%HCl + 15 ppmO(2) + N-2, and 0.1%HCl + 450 ppmO(2) + N-2. All exposures were carried out in the temperature range between 350 and 500 degrees C (30 degrees C steps) for up to 900 h. Parabolic, paralinear, and linear mass change dependent on time, temperature, and atmosphere was observed, the metal consumption as a function of temperature was determined, and the corrosion scales were analyzed and compared with results of field tests. Finally it is shown that the test results obtained from low-oxygen atmospheres match best the corrosive scales observed in field-tested samples.