EVALUATION OF HIGH NI-CR-MO ALLOYS FOR THE CONSTRUCTION OF SULFUR-DIOXIDE SCRUBBER PLANTS

Corrosion in wet lime/limestone systems used for flue gas desulfurizat ion in thermal power plants is of great concern. The frequent variatio ns in acidity and in chloride and fluoride ion concentrations experien ced by such systems pose a serious threat to the materials of construc tion. Currently used materials mostly type 316L stainless steel often fail to meet their life expectancy. The present study evaluates the pe rformance of advanced Ni-Cr-Mo alloys 59 and C-276 in a simulated sulf ur dioxide scrubber environment. Accelerated tests showed that high Ni -Cr-Mo alloys have little tendency to leach metal ions such as chromiu m, nickel, and molybdenum at different impressed potentials. Scanning electron microscopy was used to examine the morphology of pitting atta ck.