Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of alloys for use in USC systems, with emphasis placed on applications in high- and intermediate-pressure turbines

Alman, D. E.

Bullard, S. J.

Covino, B. S., Jr.

Holcomb, G. R.

Ziomek-Moroz, M.

UNT Digital Library

Oxidation of Alloys Targeted for Advanced Steam Turbines Gordon R. Holcomb, Bernard S. Covino, Jr., Sophie J. Bullard,  Malgorzata Ziomek-Moroz, and David E. Alman Albany Research Center, U. S. Department of Energy, 1450 Queen Ave SW, Albany, OR 97321 Email: holcomb@alrc.doe.gov; Telephone: (541) 967-5874; Fax: (541)-967-5914 Email: covino@alrc.doe.gov; Telephone: (541) 967-5828; Fax: (541)-967-5914 Email: bullard@alrc.doe.gov; Telephone: (541) 967-5989; Fax: (541)-967-5914 Email: moroz@alrc.doe.gov; Telephone: (541) 967-5943; Fax: (541)-967-5914 Email: alman@alrc.doe.gov; Telephone: (541) 967-5885; Fax: (541)-967-5914  Abstract Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions.  Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C.  This research examines the steamside oxidation of alloys for use in USC systems, with emphasis placed on applications in high- and intermediate-pressure turbines.    Oxidation of Alloys Targeted for Advanced Steam TurbinesTMS, San Antonio, March 12-16, 2006Office of Fossil EnergyGordon R. Holcomb, Bernard S. Covino, Jr., Sophie J. Bullard, Malgorzata Ziomek-Moroz, and David E. AlmanNational Energy Technology LaboratoryNETL-Albany1450 Queen Ave. SW, Albany OR 97321Outline• Introduction and Background• Research Approach• Results of Research in Progress• Summary• Project funded out of the Advanced Research (AR) Program of Fossil Energy (FE) of DOE• In support of DOE Advanced Power System goals of 60% efficiency from coal generation that require USC steam turbine conditions of: −760°C (1400°F) −37.9 MPa (5500 psi)IntroductionEfficiency Improvement over a  Subcritical 16.5 MPa/538°C/ 538°C Plant  Steam Conditions Recent Power  Plant Examples Net Percentage Point Increase in Efficiency Net Plant Efficiency, % 28.4 MPa/538/566°C Schwarze – 1998 2.9 39.9 28.4 MPa/566/593°C Nanaoota 1 – 1995 Noshiro 2 – 1995 Haramachi 1 – 1997 Millmerra – 2002 4.0 41.0 28.4 MPa/593/593°C Matsuura 2 – 1997 Misumi 1 – 1998 Haramachi 2 – 1998 Tchibana Bay – 2000 Bexback – 2002 4.5 41.5 31.0 MPa/593/593°C Lubeck – 1995 Alvedore 1 – 2000 4.9 41.9 31.0 MPa/593/621°C Westfalen – 2004 5.2 42.2 31.0 MPa/593/593/593°C Nordjylland - 1998 6.5 43.5      Each 1% increase in efficiency eliminates ~1,000,000 tons of CO2emissions over the lifetime of an 800-MW plantSwanekamp, 2002 112 GW New Coal Capacity By 2025 (Accounts for 42% of New Capacity Additions) New Electricity Capacity Additions (EM Reference Case) 2002-2010 2011-2015 2016-2020 2021-2025 Source: Data Derived From EIA Annual Energy Outlook 2004 - NEfL CO- Scott Kirm, KlW'a@I~t~.doe.~OV OCES 12/22/20# Erik muster, ~ r t k s h u s t e ~ . n ~ . d s e . ~ o v  Oak Creek WisconsinTwo 600 MWDevelopment 12/2004In Service 2009-2010Powder River Basin Sub-BituminousCouncil Bluffs Iowa790 MWConstruction 8/2004In Service 2007CoalTrimble County Kentucky750 MWProposed 11/2004In Service 2010Illinois Basin CoalBabcock-Hitachi Supercritical SlidingPressure Operation Benson BoilerBabcock-Hitachi Steam Turbine25.4 MPa/566°C/593°C • Determine the steamside oxidation behavior of target alloys for use in USC turbines• Determine the role of pressure on oxidation mechanisms• Examine curvature effects on spallationResearch GoalsHigh Pressure (HP) TurbineKern et al., 2004Steam Cooled IP TurbineKern et al., 2004Engineering OptionsFukuda et al., 2004Closer to usage are steam-cooled, high temperature, intermediate pressure turbine sectionsCost vs TemperatureMasuyama, 2004No Materials• Ultra Supercritical Steam Exposures−Temperatures 593 to 760°C (1112-1400°F)−Pressures of 2400 to 5500 psi (16.5-37.9 MPa)• Cyclical Oxidation in Moist Air−Hourly cycles to examine adhesion and spallation behavior of protective oxides• TGA in Steam+Argon−Determine oxidation mechanisms, kinetics, activation energies• Furnace Exposures in Moist Air−Economical long-term testsResearch ApproachAlloy CompositionsNominal compositions of alloys of interest for USC turbine applications.   Alloy Fe Cr Ni Co Mo Nb C Si Mn Ti Al Other 12 Bal 11  3  0.07 0.1 0.3 0.2   3 W 0.2 V 0.04 Nd0.04 N 6W  23 43 0.18 0.08 0.4 1.2 0.08 6 W 0.003 B 617 UNS N06617  22 55 12.5 9  0.07    1  230 UNS N06230 <3 22 55 <5 2  0.1    0.35 14 W <0.015B0.02 La 740 1 24 49 20 0.5 1.8  0.5  1.6 0.75  90 UNS N07090 1.5 19.5 55.5 18   0.06   2.4 1.4  718 UNS N07718 18.5 19.0 52.5  3 5.1 0.08 max   0.9 0.5 0.15 Cu max J1  12.1 Bal  18     1 0.8  J5  12.5 Bal  22    0.5 1  0.04 Y  • High Strength Alloys−12 -- 230-- 617−6W -- 740• Additional Ni-base superalloys−90 -- 718• Also-- J1 -- J5Highest Strength in Alloy CategoryCandidate Blade Materials (EPRI)Low CTE Nickel AlloysCandidate alloys for USC turbine applications5/30/02 3102c1.1Maximu m Allowable Stre ss  ( ks i)3020010Temperature (ºF)Temperature (ºC)210140070Maximum Al lowa bl e St ress  (MP a)800 900 1000 1100 1200 1300 1400 1500 1600 1700400 600 700 900500 800Ferritic Nickel AlloysAusteniti cHR3CHaynes 230Inco 740T23T9145TM800HTSuper304H347HFGE911T92T122HR120HR6WIn617Mod NF12800HTAC66Pd = 7000 psigPd = 6500 psigPd = 6000 psigPd = 5500 psigPd = 5000 psigPd = 4500 psigPd = 4000 psigAlloy StrengthViswanathan, Armor & Booras 20037406172306WDistilled WaterSyringe PumpBleed ValveControl ValveAutoclaveRelief ValveCheck ValveRadiant CoolerCoolingWaterHeater20 C550 CControlinlet pressureControloutlet flow760C (1400F)37.9 MPa (5500 psi)Feed water DO and Conductivity measurementUSC Test LoopUSC Feed Water SystemHigh PressurePumpConductivityConductivityHigh PurityInlet WaterAr + 0.5%O2Ar + 0.5%O2Gas OutletGas OutletDilute NH4OHWater Chemistry Goal150-200 ppb DO9.2-9.6 pHpHPumpDissolvedOxygenpHPumpDissolvedOxygenSampling TapSampling TapThermogravimetric analysis to give kinetics and corrosion mechanism information.Temperatures up to 800°CFlowing steam plus ArAtmospheric pressureFeed water is oxygen saturatedTGA Testing in SteamTGA ResultsThermogravimetric analysis (TGA) for 300 hr tests in O2-saturated steam plus 60%Ar at 800°C  Alloy %Cr Reaction Order, n ParabolicR2 Parabolic Rate Constant, kp mg2cm-4s-1 12 (9.5Cr) 9.5 1.78 1.000 1.2 × 10-3 12 (9.5Cr) 9.5 1.90 1.000 1.4 × 10-3 12 (10.5Cr) 10.5 1.70 1.000 1.6 × 10-3 12 (10.5Cr) 10.5 1.76 0.995 1.7 × 10-3 J1 12.1 1.73 0.990 3.5 × 10-7 J5 12.5 1.91 0.990 1.5 × 10-7 617 22 1.62 0.960 1.4 × 10-7 617 22 2.63 0.585 3.9 × 10-8 230 22 1.78 0.878 6.9 × 10-8 230 22 1.79 0.645 3.7 × 10-8 6W 23 1.87 0.524 3.3 × 10-8 740 24 2.20 0.527 7.2 × 10-7       Furnace Exposures0.00.20.40.60.81.01.20 500 1000 1500 2000 2500 3000Time, HoursJ5   3% H2O-Air  X+800C760C700C650C051015200 500 1000 1500 2000 2500 3000Time, Hours 12 (9.5Cr)   3% H2O-Air  X+800C760C700C650C Fe-2.25Cr at 550CFe-9 to 12Cr at 600CWright and Pint, 2002051015200 500 1000 1500 2000 2500 3000Time, Hours 12 (10.5Cr)   3% H2O-Air  X+800C760C700C650C Fe-2.25Cr at 550CFe-9 to 12Cr at 600CWright and Pint, 20020.00.20.40.60.81.01.20 500 1000 1500 2000 2500 3000Time, HoursJ1   3% H2O-Air  X+800C760C700C650C0.00.10.20.30.40.50.60 500 1000 1500 2000 2500 3000Time, Hours230   3% H2O-Air  X+800C760C700C650CFurnace Exposures0.00.10.20.30.40.50.60 500 1000 1500 2000 2500 3000Time, Hours 6W   3% H2O-Air  X+800C760C700C650C0.00.10.20.30.40.50.60 500 1000 1500 2000 2500 3000Time, Hours 90   3% H2O-Air  X+800C760C700C650C0.00.10.20.30.40.50.60 500 1000 1500 2000 2500 3000Time, Hours718   3% H2O-Air  X+800C760C700C650C0.00.10.20.30.40.50.60 500 1000 1500 2000 2500 3000Time, Hours617   3% H2O-Air  X+800C760C700C650C46 kJ/mol32 kJ/mol58 kJ/mol0.00.10.20.30.40.50.60 500 1000 1500 2000 2500 3000Time, Hours740   3% H2O-Air  X+800C760C700C650C62 kJ/molScale adhesion information during thermal cyclesTemperatures up to 800°CFlowing steam/air mixtureAtmospheric pressureHourly cycles7 samples at a timeCyclic Oxidation Concave Convex1210.5 Cr2” O.D.Curvature SamplesArmitt et al., 1978Stored Energy ModelFerriticSteelsAusteniticSteels740-0.3-0.10.10.30.50 500 1000 1500 2000Number of Cycles (Hours)74050% H2O-50% Air760C760°C Air + 50% H2O300 Cycles 2000 CyclesMn-Ti Rich Outer Oxide-0.3-0.10.10.30.50 500 1000 1500 2000Number of Cycles (Hours)23050% H2O-50% Air760C 230760°C Air + 50% H2O300 Cycles 2000 CyclesW-Mo RichPrecipitates718-0.3-0.10.10.30.50 500 1000 1500 2000Number of Cycles (Hours)50% H2O-50% Air760C718300 Cycles 2000 Cycles760°C Air + 50% H2O-0.3-0.10.10.30.50 500 1000 1500 2000Number of Cycles (Hours)61750% H2O-50% Air760C617760°C Air + 50% H2O300 Cycles 2000 Cycles-0.3-0.10.10.30.50 500 1000 1500 2000Number of Cycles (Hours)50% H2O-50% Air760C6W6W Concave6W Convex X+6W760°C Air + 50% H2O300 Cycles 2000 CyclesMn-Cr Rich Outer OxideW Rich Precipitates-0.3-0.10.10.30.50 500 1000 1500 2000Number of Cycles (Hours)50% H2O-50% Air760C9090760°C Air + 50% H2O300 Cycles 2000 CyclesNi-Co-Cr-Ti OxideTi-Cr Oxide12-200204060801000 500 1000 1500 2000Number of Cycles (Hours)1210.5 Cr9.5 Cr50% H2O-50% Air760C X760°C Air + 50% H2O300 Cycles2000 Cycles12 10.5 CrFe-Cr Oxide (Dark Grey)Fe-Cr Alloy (Light Grey)W-Rich (White)Fe Oxide (outer)Fe (1 Co) Oxide Inner12Curvature-200204060801000 500 1000 1500 2000Number of Cycles (Hours)1250% H2O-50% Air760C10.5 Cr Convex10.5 Cr Concave+760°C Air + 50% H2O2302000 HrFurnace Exposure3% Water in Air at 760C300 HrTGA Exposure40% Water in Argon at 800C300 CyclesCyclic Exposure50% Water in Air at 760C2000 CyclesCyclic Exposure50% Water in Air at 760CW-Mo RichPrecipitatesSummary• DOE Advanced Power System goal of 60% efficiency from coal generation− Require USC steam turbine conditions of 760°C & 37.9 MPa• Mass Change Results:− From a simplistic mass change standpoint, all of the Ni-base alloys look acceptable at up to 800°C, and Alloy 12 up to 700°C• Alloy Degradation Below Oxide Scale− All alloys show degradation below the oxide scale• 740 shows the least • 230 is next best• Curvature− No evidence of curvature effects shown

Oxidation of alloys targeted for advanced steam turbines

https://digital.library.unt.edu/ark:/67531/metadc900861/m2/1/high_res_d/922934.pdf

Oxidation of alloys targeted for advanced steam turbines

Abstract

Similar works

Full text

Available Versions

UNT Digital Library