Hot Corrosion at Air-Ports in Kraft Recovery Boilers
Hot corrosion can occur on the cold-side of airports in Kraft recovery boilers. The primary corrosion mechanism involves the migration of sodium hydroxide and potassium hydroxide vapors through leaks in the furnace wall at the airports and their subsequent condensation. It has been reported that stainless steel is attacked much faster than carbon steel in composite tubes, and that carbon steel tubing, when used with a low-chromium refractory, does not exhibit this type of corrosion. For hot corrosion fluxing of metal oxides, either acidic or basic fluxing takes place, with a solubility minimum at the basicity of transition between the two reactions. For stainless steel, if the basicity of the fused salt is between the iron and chromium oxide solubility minima, then a synergistic effect can occur that leads to rapid corrosion. The products of one reaction are the reactants of the other, which eliminates the need for rate-controlling diffusion. This effect can explain why stainless steel is attacked more readily than carbon steel.
- Research Organization:
- Albany Research Center (ARC), Albany, OR (United States)
- Sponsoring Organization:
- USDOE - Office of Fossil Energy (FE)
- OSTI ID:
- 898080
- Report Number(s):
- DOE/ARC-2002-018; R&D Project: AMP-005; TRN: US200703%%344
- Resource Relation:
- Conference: John Stringer Symposium on High Temperature Corrosion, at ASM/TMS Materials Solutions, Indianapolis, IN, Nov. 5-7, 2001
- Country of Publication:
- United States
- Language:
- English
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