Quantitative tool for FGD alloy selection based on pH and chloride
- Radian International, Austin, TX (United States)
The pitting resistance equivalent (PRE) parameter is a widely recognized tool for ranking the relative pitting and crevice corrosion resistance of austenitic stainless steels and chromium-containing nickel-base alloys. However, it has not previously been correlated to alloy performance under specific flue gas desulfurization (FGD) conditions of temperature, chloride, and pH. Quantitative correlations have now been developed between the extended PRE parameter--which includes the effects of nitrogen and tungsten as well as chromium and molybdenum--and predicted alloy performance under FGD conditions based on previously published Schillmoller-Kijhlert pH-Chloride diagrams. The resulting equations allow estimation of the threshold chloride level for significant localized corrosion in mechanical crevices or under deposits on fouled surfaces based on alloy composition and solution pH. While developed for lime/limestone FGD slurry, the correlations are valid for other aerated aqueous solutions with pH between 4 and 8 and temperatures between 49 and 66 C (120--150 F). Results for 35 FGD construction alloys are presented for three cases: the nominal chloride thresholds, the conservative chloride thresholds, and the critical, or ultraconservative, chloride thresholds.
- OSTI ID:
- 350050
- Report Number(s):
- CONF-980316--
- Country of Publication:
- United States
- Language:
- English
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