Presentation on theme: "High Temperature Alloys for Power Plant Applications"— Presentation transcript:
1 High Temperature Alloys for Power Plant Applications ARIPPA MeetingApril 26th, 2005Jason WilsonRolled Alloys
2 Nominal Chemistries Alloy UNS Ni Cr Fe Si Other 304 SS S30400 9 18.3 70RA253MAS309081121651.7Ce, N309 SSS308151323620.8310 SSS310082025520.5RA330®N083303519431.25RA353MAS35315361.2Alloy 601N0660161.522.5140.2Al
3 High Temperature Concerns DistortionCreep DeformationThermal ExpansionCorrosionOxidationTemperature LimitationsErosionSulfidationMolten Salts
4 Stress Do not subject alloys to undue stress Uneven Heating Thermal ExpansionThermal Shock
5 Uneven Heating Uneven Thermal Expansion Typical Causes Buckling/WarpingCrackingTypical CausesFlame ImpingementLarge variation in cross sectionSharp temperature gradientsHOTCOOLRA 253 MA Burner Can
6 Thermal Expansion At 1800F, a 20 foot RA330 pipe expands over 4 inches KeysMajorAllow for expansion in the designMinorHigher strength alloyLower coefficient of thermal expansionAlloy 600 (3.75 in)Railroad on a hot day
7 Coefficient of Thermal Expansion (in/in°F x 10-6) Alloy% Nickel1600oF304 SS811.0309 SS1310.1RA253MA1110.6310 SS2010.15800HT3210.2RA330359.8RA353MA9.86Alloy 601619.5
8 Strength Ensure adequate alloy strength at temperature Review Creep-Rupture dataShort Term Data is not representative of how the alloy will act in long term service.
9 Strength Raising Creep Strength Carbon Nitrogen Nickel Others Use H gradesMin 0.4% Carbon & Coarse GrainsNitrogenRA 253 MA and RA 353 MANickelOthersCo, Mo, W
11 Strength Creep occurs above roughly 1000oF Permanent Deformation or FlowTime DependentLower Stress than Y.S.
12 10,000 Hr Average Stress to Rupture AlloyUNS Number1600oF1800oF1900oF2000oF304 SSS304001,400309 SSS309081,600560RA253MAS308152,5001,150860680310 SSS310081,500660800HTN088113,5001,300890480RA330N083301,700630400280RA353MAS353152,600930Alloy 601N066011,200620
13 Strength Incinerator bed 1920oF (Average) Replaced RA330 6 months lifeRA 353 MA lasting 8-9 months
14 Strength Horizontal Radiant U-tubes. 6 inch OD and 11ga wall. Condition after 10 months.Batch Annealing at 1800°F.Exothermic Atmosphere.Operation 5 days/week 3 shifts
15 253MA Circulating Fluidized Bed 8-1/2 foot diameter x 23 foot long dip tubes.Two per boiler, eight boilers on site°F TemperaturesFuel – 70% Illinois Coal, 30% Powder River Basin, Tire ChipsDip tubes installed in 1999, Others in since 1998,- 310 Stainless lasted 2 years prior to removal due to distortion
16 Strength - RA253MA pans for the production of foam glass insulation Previous alloy used type 309 stainlessProcess temperature 1600°F
17 Strength RA 353 MA pack coating retort. 36 in. diameter 48 in. high 3/8 inch thick°F – Argon on insidePhoto after 24 months in serviceRA330 typically distorted 8 months
18 Tube Supports Fired Boilers RA353MA heavy plate used as a header support.Replaced RA330
20 Temperature Limitations All alloys have their limits.Limiting FactorsOxidationNot melting pointStrength310SS at 2100F
21 Oxidation Spallation of the protective oxide scale Enhancers Thinning Internal oxide penetrationEnhancersChromiumSiliconAluminumCeriumType 310 stainless thermocouple tube oxidized from operation at 2100 deg F
25 Tube Spacers RA353MA hand cuff bars on a packaged boiler firing with natural gas.
26 Cyclones Western U.S. Coke Plant Alloy 353 MA alloy used since 19993 installation areasAverage months of serviceStill in good condition. Evaluating weld repair of suspension tabs and reuse.½” thick materialRA353MA shown after 1 year service during inspection °F typical
27 Sulfidation Attack by sulfur compounds Molten Ni-Ni-S eutectic SO2, H2SAt 1200°F and aboveMolten Ni-Ni-S eutecticHigher nickel alloys most susceptibleSulfidation of cast heat resistant alloy used for a tire drop chute (Cement)
28 Sulfur/Chlorine Attack oFSlab Reheat Furnace Recuperator11 Months ExposureRA353MA replaced 309 with high siliconIncreased life from 7 months to over 24 months19Cr-11Ni-2Si
34 Coal Tips 253MA used extensively for coal nozzles 309 or 310 SS commonly used for the air nozzles353MA used at some plants for upper elevations of the boiler353MA used at a Midwestern utilitySpecified since 2000Replaced 253MA
35 Tube Shields RA353MA used in supercritical boilers Specified at one US Utility for hottest area of superheaterReplaced type 309 stainlessService life of 6 years
36 Tube Shields – Paper Mill FuelPropane – Start upWaste OilsHog FuelBunker CS35315 used since 19981 year life expectancy
37 Tube Shields S35315 used in CFB boiler Protect primary superheater tubes1616 deg FHigh S, High Cl coalExtensive Soot Blowing due to foulingReplaced 309 SSStill in service after 28 months.
38 Erosion 63 inch diameter 353MA cyclone Temperatures Refuse fired 1750 to 2192°FRefuse firedInitial unit in service for 1 yearRedesigned cyclone made of 353MA