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Barberton, OH, United States

Robitz E.S.,Babcock and Wilcox Research Center | Tanzosh J.M.,Babcock
Advances in Materials Technology for Fossil Power Plants - Proceedings from the 6th International Conference | Year: 2011

The U.S. Department of Energy (DOE) and the Ohio Coal Development Office (OCDO) are sponsoring the "Boiler Materials for Ultrasupercritical Coal Power Plants" program to characterize and qualify candidate materials for service in advanced ultrasupercritical (A-USC) boilers. Advanced ferritic materials, austenitic stainless steels and nickel-based alloys are being evaluated. When they are exposed to A-USC boiler conditions, these materials must demonstrate high temperature strength and creep resistance, as well as resistance to both steam-side oxidation and fire side corrosion. As part of the DOE/OCDO program, the fire side corrosion resistance of six monolithic tube materials and twelve weld overlay/tube material combinations were evaluated. The performance of these materials was compared through in situ testing of two superheater test sections within the Unit 1 boiler at Reliant Energy's Niles Plant in Ohio. This boiler burns high sulfur coal and thus provides an aggressive and discriminating test environment. The results of this testing show that, after about 12 months of exposure at temperature, Inconel 740 proved to have the lowest wastage rate among the monolithic tube materials. The results also show that the EN72 weld overlay provided good wastage resistance regardless of the substrate. The relative rankings of all of the candidate materials are provided herein. Copyright © 2011 Electric Power Research Institute Distributed by ASM International®. All rights reserved. Source


Pitz R.W.,Vanderbilt University | Hu S.,Babcock and Wilcox Research Center | Wang P.,Xiamen University
Progress in Energy and Combustion Science | Year: 2014

Tubular flames are ideal for the study of stretch and curvature effects on flame structure, extinction, and instabilities. Tubular flames have uniform stretch and curvature and each parameter can be varied independently. Curvature strengthens or weakens preferential diffusion effects on the tubular flame and the strengthening or weakening is proportional to the ratio of the flame thickness to the flame radius. Premixed flames can be studied in the standard tubular burner where a single premixed gas stream flows radially inward to the cylindrical flame surface and products exit as opposed jets. Premixed, diffusion and partially premixed flames can be studied in the opposed tubular flame where opposed radial flows meet at a cylindrical stagnation surface and products exit as opposed jets. The tubular flame flow configurations can be mathematically reduced to a two-point boundary value solution along the single radial coordinate. Non-intrusive measurements of temperature and major species concentrations have been made with laser-induced Raman scattering in an optically accessible tubular burner for both premixed and diffusion flames. The laser measurements of the flame structure are in good agreement with numerical simulations of the tubular flame. Due to the strong enhancement of preferential diffusion effects in tubular flames, the theory-data comparison can be very sensitive to the molecular transport model and the chemical kinetic mechanism. The strengthening or weakening of the tubular flame with curvature can increase or decrease the extinction strain rate of tubular flames. For lean H 2-air mixtures, the tubular flame can have an extinction strain rate many times higher than the corresponding opposed jet flame. More complex cellular tubular flames with highly curved flame cells surrounded by local extinction can be formed under both premixed and non-premixed conditions. In the hydrogen fueled premixed tubular flames, thermal-diffusive flame instabilities result in the formation of a uniform symmetric petal flames far from extinction. In opposed-flow tubular diffusion flames, thermal-diffusive flame instabilities result in cellular flames very close to extinction. Both of these flames are candidates for further study of flame curvature and extinction. © 2014 Elsevier Ltd. All rights reserved. Source


Siefert J.A.,Babcock and Wilcox Research Center | Sanders J.M.,Babcock and Wilcox Research Center | Tanzosh J.M.,Babcock and Wilcox Research Center | Newell Jr. W.F.,Euroweld Ltd. | Shingledecker J.P.,EPRI
Materials at High Temperatures | Year: 2010

Dissimilar metal welds (DMW's) between ferritic and austenitic materials at elevated temperatures have concerned boiler manufacturers and operators for decades because of the proven potential for premature failure. The industry has desired an improved filler metal that would minimize or eliminate DMW failures and, with the current trend toward higher boiler steam pressures and temperatures, have suitable creep strength for joining higher strength materials such as Grade 91 steels After years of research, the Electric Power Research Institute (EPRI) concluded the development and commercialization of a nickel-based filler metal, EPRI P87, for application in shielded metal arc welding (SMAW). This work describes the subsequent development of an EPRI P87 solid wire welding product for application in gas tungsten arc and gas metal arc welding (GTAW and GMAW) processes, and the initial research into the performance of DMWs produced with the new solid wire P87 product. A 135kg heat of solid wire was produced and tested using various welding processes and evaluation methods to ensure that the material would meet required weldability and design specifications. Welding methods included GMAW-P, GTAW and hot-wire GTAW in welds up to 50 mm in thickness. The weld joint tested was a dissimilar metal weld of grade 91 to 347H, which was assessed using microstructure evaluation, creep testing, hot tensile testing, circular patch, and edge build-up investigations to examine hot-cracking susceptibility. This paper summarizes the research completed to date on the EPRI 87 filler wire which supports the acceptability of this material for its intended use in high-temperature power generation applications. © 2010 Science Reviews 2000 Ltd. Source


Siefert J.A.,Babcock and Wilcox Research Center | Tanzosh J.M.,Babcock and Wilcox Research Center | Shingledecker J.P.,EPRI
Advances in Materials Technology for Fossil Power Plants - Proceedings from the 6th International Conference | Year: 2011

Dissimilar metal welds (DMW's) between ferritic and austenitic materials at elevated temperatures have concerned boiler manufacturers and operators for decades because of the proven potential for premature failure. With the current trend toward ever higher pressures and temperatures to achieve increased boiler efficiencies, it would be advantageous to have a superior weld metal and joint design that would optimize economy of the newer boilers and help avoid the use of austenitic materials for steam headers and piping. EPRI has developed a new filler metal to improve the performance of DMW's, EPRI P87. Previously, work has been reported on the development of EPRI P87 shielded metal arc welding electrode, gas-tungsten arc welding fine-wire, and the utilization of EPRI P87 in an ultra-supercritical steam boiler built and constructed by B&W. This paper discusses the weldability of EPRI P87 consumables using various test methods such as varestraint testing (trans and spot), long-term creep testing (∼10,000 hour running tests), procedure qualification records of tube to tube weldments between traditional/ advanced austenitics and creep-strength enhanced ferritic steels, and elevated temperature tensile testing. Finally, macros taken from the procedure qualification records were examined using light microscopy to verify the weldability and elimination of cracking between all possible material combinations. All these data show EPRI P87 is a weldable alloy which has a number of advantages for use in DMW applications. The data also show that for specific weld joint configurations, procedure qualifications may require the use of high-temperature tensile data. Copyright © 2011 Electric Power Research Institute Distributed by ASM International®. All rights reserved. Source


Stimpson C.K.,Brigham Young University | Brunner D.R.,Brigham Young University | Reeder T.A.,Brigham Young University | Tree D.R.,Brigham Young University | And 2 more authors.
Western States Section of the Combustion Institute Spring Technical Meeting 2012 | Year: 2012

Deposit samples for eight coals were collected on temperature controlled, stainless steel probes in reducing and oxidizing regions of a 160 kWth , pulverized coal reactor. The samples were analyzed using a scanning electron microscope equipped with energy-dispersive spectroscopy to determine particle sizes and semi-quantitative elemental compositions. An ash analysis was performed on the samples collected from both the top (upstream side) and the bottom (downstream side) of each of the probes. Each particle consisted of a unique composition of elements. The average sulfur concentrations measured in the deposits were not found to correlate with sulfur concentrations of their respective coals, but they were strongly correlated with the calcium and iron contents of their respective coals. The high-calcium, subbituminous and lignite coals produced high sulfur concentrations in the deposits, particularly in the downstream, oxidizing deposits. The high-iron, bituminous coals produced high sulfur concentrations in the deposits; the highest concentrations of sulfur were found in the upstream, reducing deposits. The relatively low-calcium and low-iron bituminous coals produced low sulfur concentrations in the deposits. One coal was an exception to this trend, as the deposits from this coal exhibited low sulfur concentrations despite the high iron concentrations in the coal. The coal highest in pyrite was the only coal that produced discrete deposit particles rich in iron and sulfur but not in calcium. Copyright © (2012) by the Western States Section/Combustion Institute. Source

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