High Temperature Alloys for Power Plant Applications ARIPPA Meeting April 26th, 2005 Jason Wilson Rolled Alloys

Nominal Chemistries Alloy UNS Ni Cr Fe Si Other 304 SS S30400 9 18.3 70 RA253MA S30908 11 21 65 1.7 Ce, N 309 SS S30815 13 23 62 0.8 310 SS S31008 20 25 52 0.5 RA330® N08330 35 19 43 1.25 RA353MA S35315 36 1.2 Alloy 601 N06601 61.5 22.5 14 0.2 Al

High Temperature Concerns Distortion Creep Deformation Thermal Expansion Corrosion Oxidation Temperature Limitations Erosion Sulfidation Molten Salts

Stress Do not subject alloys to undue stress Uneven Heating Thermal Expansion Thermal Shock

Uneven Heating Uneven Thermal Expansion Typical Causes Buckling/Warping Cracking Typical Causes Flame Impingement Large variation in cross section Sharp temperature gradients HOT COOL RA 253 MA Burner Can

Thermal Expansion At 1800F, a 20 foot RA330 pipe expands over 4 inches Keys Major Allow for expansion in the design Minor Higher strength alloy Lower coefficient of thermal expansion Alloy 600 (3.75 in) Railroad on a hot day

Coefficient of Thermal Expansion (in/in°F x 10-6) Alloy % Nickel 1600oF 304 SS 8 11.0 309 SS 13 10.1 RA253MA 11 10.6 310 SS 20 10.15 800HT 32 10.2 RA330 35 9.8 RA353MA 9.86 Alloy 601 61 9.5

Strength Ensure adequate alloy strength at temperature Review Creep-Rupture data Short Term Data is not representative of how the alloy will act in long term service.

Strength Raising Creep Strength Carbon Nitrogen Nickel Others Use H grades Min 0.4% Carbon & Coarse Grains Nitrogen RA 253 MA and RA 353 MA Nickel Others Co, Mo, W

Strength Creep Demonstration RA 253 MA, 601, 310, 321 0.040” thick rings Temperature: 1832F Time: 35 hours

Strength Creep occurs above roughly 1000oF Permanent Deformation or Flow Time Dependent Lower Stress than Y.S.

10,000 Hr Average Stress to Rupture Alloy UNS Number 1600oF 1800oF 1900oF 2000oF 304 SS S30400 1,400 309 SS S30908 1,600 560 RA253MA S30815 2,500 1,150 860 680 310 SS S31008 1,500 660 800HT N08811 3,500 1,300 890 480 RA330 N08330 1,700 630 400 280 RA353MA S35315 2,600 930 Alloy 601 N06601 1,200 620

Strength Incinerator bed 1920oF (Average) Replaced RA330 6 months life RA 353 MA lasting 8-9 months

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

253MA Circulating Fluidized Bed 8-1/2 foot diameter x 23 foot long dip tubes. Two per boiler, eight boilers on site - 1600-1650°F Temperatures Fuel – 70% Illinois Coal, 30% Powder River Basin, Tire Chips Dip tubes installed in 1999, Others in since 1998, - 310 Stainless lasted 2 years prior to removal due to distortion

Strength - RA253MA pans for the production of foam glass insulation Previous alloy used type 309 stainless Process temperature 1600°F

Strength RA 353 MA pack coating retort. 36 in. diameter 48 in. high 3/8 inch thick 1675-2000°F – Argon on inside Photo after 24 months in service RA330 typically distorted 8 months

Tube Supports Fired Boilers RA353MA heavy plate used as a header support. Replaced RA330

High Temperature Corrosion

Temperature Limitations All alloys have their limits. Limiting Factors Oxidation Not melting point Strength 310SS at 2100F

Oxidation Spallation of the protective oxide scale Enhancers Thinning Internal oxide penetration Enhancers Chromium Silicon Aluminum Cerium Type 310 stainless thermocouple tube oxidized from operation at 2100 deg F

Suggested Temperature Limits (Air) 1000 1200 1400 1600 1800 2000 2200 2400 304SS 309SS 310SS RA 253 MA® RA330 Alloy 600 RA 353 MA® Alloy 601 RA333® RA 602 CA™

Oxidation Resistance Cyclical Testing 1600 Hrs

Oxidation Resistance Cyclic Testing 3000 Hrs

Tube Spacers RA353MA hand cuff bars on a packaged boiler firing with natural gas.

Cyclones Western U.S. Coke Plant Alloy 353 MA alloy used since 1999 3 installation areas Average 12-18 months of service Still in good condition. Evaluating weld repair of suspension tabs and reuse. ½” thick material RA353MA shown after 1 year service during inspection. 2000°F typical

Sulfidation Attack by sulfur compounds Molten Ni-Ni-S eutectic SO2, H2S At 1200°F and above Molten Ni-Ni-S eutectic Higher nickel alloys most susceptible Sulfidation of cast heat resistant alloy used for a tire drop chute (Cement)

Sulfur/Chlorine Attack 1470-1650oF Slab Reheat Furnace Recuperator 11 Months Exposure RA353MA replaced 309 with high silicon Increased life from 7 months to over 24 months 19Cr-11Ni-2Si

Sulfidation

Chloride Attack Chloride Attack Thick Porous Scale Rapid Thinning Intergranular Attack 310 stainless tubeshield from refuse fired boiler.

Tube Supports – Escatron (Spain) Replaced RA253MA Pressurized Fluid Bed Boiler 6.8% Sulfur Lignite Earlier Units <3.6% Sulfur TIDD, Vartan RA253MA successful Coupon Testing 11 months 1475-1650°F RA353MA – 0.1 mm RA253MA – 1.1 mm

Flap Gates Cement Kilns Feeding of Scrap Tires RA353MA in use in 3 cement plants to date in North & South America

Erosion @ 1292oF (700oC)

Coal Tips 253MA used extensively for coal nozzles 309 or 310 SS commonly used for the air nozzles 353MA used at some plants for upper elevations of the boiler 353MA used at a Midwestern utility Specified since 2000 Replaced 253MA

Tube Shields RA353MA used in supercritical boilers Specified at one US Utility for hottest area of superheater Replaced type 309 stainless Service life of 6 years

Tube Shields – Paper Mill Fuel Propane – Start up Waste Oils Hog Fuel Bunker C S35315 used since 1998 1 year life expectancy

Tube Shields S35315 used in CFB boiler Protect primary superheater tubes 1616 deg F High S, High Cl coal Extensive Soot Blowing due to fouling Replaced 309 SS Still in service after 28 months.

Erosion 63 inch diameter 353MA cyclone Temperatures Refuse fired 1750 to 2192°F Refuse fired Initial unit in service for 1 year Redesigned cyclone made of 353MA

Erosion Pressurized Fluidized Bed Combustor Cyclone AEP TIDD Project

Erosion RA253MA Witch’s Hat Fluid Bed Boiler System

Municipal Utility - Wisconsin Foster Wheeler CFB Fuel Petcoke/Paper Pellets Replaced RA253MA Transfer Line Fuel feed chute Ash Drains Installed Early 2004 Selected for Abrasion/Distortion Areas

Relative Costs Alloy Relative Cost RA309 1.00 RA 353 MA 2.70 RA 253 MA 1.30 RA601 3.60 RA310 1.35 RA 330 2.20 Ratios based on plate pricing during Spring 2005

Summary Distortion Corrosion Allow for Thermal Expansion Minimize uneven heating Investigate Higher Strength Alloys H grades MA grades Nickel alloys Corrosion Oxidation/Erosion High Chromium Ce, Si, Al Additions Sulfidation Lower Nickel Chlorides Higher Nickel Moderate Chromium