Materials Performance in USC Steam Portland
Goals of the U.S. Department of Energy's Advanced Power Systems Initiatives include power generation from coal at 60% efficiency, which requires steam conditions of up to 760 C and 340 atm, co-called advanced ultrasupercritical (A-USC) steam conditions. A limitation to achieving the goal is a lack of cost-effective metallic materials that can perform at these temperatures and pressures. Some of the more important performance limitations are high-temperature creep strength, fire-side corrosion resistance, and steam-side oxidation resistance. Nickel-base superalloys are expected to be the materials best suited for steam boiler and turbine applications above about 675 C. Specific alloys of interest include Haynes 230 and 282, Inconel 617, 625 and 740, and Nimonic 263. Further validation of a previously developed chromia evaporation model is shown by examining the reactive evaporation effects resulting from exposure of Haynes 230 and Haynes 282 to moist air environments as a function of flow rate and water content. These two alloys differ in Ti and Mn contents, which may form outer layers of TiO{sub 2} or Cr-Mn spinels. This would in theory decrease the evaporation of Cr{sub 2}O{sub 3} from the scale by decreasing the activity of chromia at the scale surface, and be somewhat self-correcting as chromia evaporation concentrates the Ti and Mn phases. The apparent approximate chromia activity was found for each condition and alloy that showed chromia evaporation kinetics. As expected, it was found that increasing the gas flow rate led to increased chromia evaporation and decreased chromia activity. However, increasing the water content in moist air increased the evaporation, but results were mixed with its effect on chromia activity.
- Research Organization:
- National Energy Technology Lab. (NETL), Pittsburgh, PA, and Morgantown, WV (United States). In-house Research
- Sponsoring Organization:
- USDOE Office of Fossil Energy (FE)
- OSTI ID:
- 1039037
- Report Number(s):
- NETL-PUB-195; TRN: US201209%%122
- Resource Relation:
- Conference: Proceedings of the 25th Annual Conference on Fossil Energy Materials, Portland, OR, April 26-28, 2011
- Country of Publication:
- United States
- Language:
- English
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Materials Performance in USC Steam
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Related Subjects
AIR
ALLOYS
BOILERS
COAL
CORROSION RESISTANCE
CREEP
EFFICIENCY
EVAPORATION
EVAPORATION MODEL
FLOW RATE
GAS FLOW
HEAT RESISTING ALLOYS
NICKEL BASE ALLOYS
OXIDATION
PERFORMANCE
POWER GENERATION
POWER SYSTEMS
SPINELS
STEAM
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
VALIDATION