Understanding Corrosion Mechanisms in Oxy-Fired Systems
- ORNL
- Tennessee Technological University
Replacing air with oxygen in coal-fired boilers (i.e. oxy-firing) combined with flue gas recirculation is a leading strategy to concentrate CO{sub 2} and assist in carbon capture and sequestration. A significant area of concern is the fireside corrosion with oxy-firing due to the higher CO{sub 2} levels in the combustion gas and potentially higher SO{sub x} and H{sub 2}O levels. In order to investigate this complicated issue, laboratory experiments are being conducted with and without synthetic ash to assess the potential effect of oxy-firing on fireside corrosion rates. The initial results of this project focus on commercial and model Fe-base alloys at 600 C. Without ash, a 50%H{sub 2}O-50%(CO{sub 2}-0.15O{sub 2}) environment was the most aggressive condition, requiring higher Cr contents than 100% H{sub 2}O or Ar-50%CO{sub 2}. With the specimens covered in ash, several gas compositions were examined, including different levels of H{sub 2}O and SO{sub 2} to simulate various oxy-firing strategies. Results also are presented for several laser-clad coating compositions for protecting tubes. An additional task is examining the effect of environment on mechanical properties. Initial work studied Ni-base alloys in steam at 800 C and found little effect of steam on the creep rupture life of alloy 230 but a 35% decrease for alloy 740.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- FE USDOE - Office of Fossil Energy (FE)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1036570
- Resource Relation:
- Conference: 25th Annual Conference on Fossil Energy Materials, Portland, OR, USA, 20110426, 20110428
- Country of Publication:
- United States
- Language:
- English
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