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Sample records for boiler tube coatings

  1. Evaluation of Iron Aluminide Weld Overlays for Erosion-Corrosion Resistant Boiler Tube Coatings in Low NOx Boilers

    SciTech Connect

    Regina, J.R.; Lim, M.; Barbosa, N., DuPont, J.N.; Marder, A.R.

    2000-04-28

    Iron aluminide weld overlays containing ternary additions and thermal spray coatings are being investigated for corrosion protection of boiler tubes in Low NO{sub x} burners. The primary objective of the research is to identify overlay and thermal spray compositions that provide corrosion protection of waterwall boiler tubes.

  2. Nickel-chromium plasma spray coatings: A way to enhance degradation resistance of boiler tube steels in boiler environment

    SciTech Connect

    Sidhu, B.S.; Prakash, S.

    2006-03-15

    Boiler tube steels, namely low carbon steel ASTM-SA210-Grade A1 (GrA1), 1Cr-0.5Mo steel ASTM-SA213-T-11 (T11), and 2.25Cr-1Mo steel ASTM-SA213-T-22 (T22), were used as substrate steels. Ni-22Cr-10AI-1Y powder was sprayed as a bond coat 150 {mu}m thick before a 200 {mu}m final coating of Ni-20Cr was applied. Coatings were characterized prior to testing in the environment of a coal fired boiler. The uncoated and coated steels were inserted in the platen superheater zone of a coal fired boiler at around 755{sup o}C for 10 cycles, each 100 h. Coated steels showed lower degradation (erosion-corrosion) rate than uncoated steels showed. The lowest rate was observed in the case of Ni-20Cr coated T11 steel. Among the uncoated steels, the observed rate of degradation was the lowest for the T22 steel.

  3. Evaluation of Iron Aluminide Weld Overlays for Erosion-Corrosion Resistant Boiler Tube Coatings in Low NOx Boilers

    SciTech Connect

    Regina, J.R.

    2000-05-16

    Iron aluminide weld overlays containing ternary additions and thermal spray coatings are being investigated for corrosion protection of boiler tubes in Low NOx burners. The primary objective of the research is to identify overlay and thermal spray compositions that provide corrosion protection of waterwall boiler tubes. In the current phase of work, preliminary corrosion tests were conducted on a binary Fe-Al alloy in multiple complex gases to determine which gases will be used for testing of the ternary alloys. Preliminary solid-state corrosion tests were also conducted to simulate slag-metal interactions seen in Low NOx furnaces. Two powder compositions were chosen for testing of the ternary alloys. A matrix of alloys to be tested in both gaseous and solid-state corrosion experiments was produced based on corrosion literature.

  4. Iron aluminide weld overlay coatings for boiler tube protection in coal-fired low NOx boilers

    SciTech Connect

    Banovic, S.W.; DuPont, J.N.; Marder, A.R.

    1997-12-01

    Iron aluminide weld overlay coatings are currently being considered for enhanced sulfidation resistance in coal-fired low NO{sub x} boilers. The use of these materials is currently limited due to hydrogen cracking susceptibility, which generally increases with an increase in aluminum concentration of the deposit. The overall objective of this program is to attain an optimum aluminum content with good weldability and improved sulfidation resistance with respect to conventional materials presently in use. Research has been initiated using Gas Tungsten Arc Welding (GTAW) in order to achieve this end. Under different sets of GTAW parameters (wire feed speed, current), both single and multiple pass overlays were produced. Characterization of all weldments was conducted using light optical microscopy, scanning electron microscopy, and electron probe microanalysis. Resultant deposits exhibited a wide range of aluminum contents (5--43 wt%). It was found that the GTAW overlays with aluminum contents above {approximately}10 wt% resulted in cracked coatings. Preliminary corrosion experiments of 5 to 10 wt% Al cast alloys in relatively simple H{sub 2}/H{sub 2}S gas mixtures exhibited corrosion rates lower than 304 stainless steel.

  5. Evaluation of iron aluminide weld overlays for erosion - corrosion resistant boiler tube coatings in low NO{sub x} boilers

    SciTech Connect

    DuPont, J.N.; Banovic, S.W.; Marder, A.R.

    1996-08-01

    Low NOx burners are being installed in many fossil fired power plants in order to comply with new Clean Air Regulations. Due to the operating characteristics of these burners, boiler tube sulfidation corrosion is often enhanced and premature tube failures can occur. Failures due to oxidation and solid particle erosion are also a concern. A program was initiated in early 1996 to evaluate the use of iron aluminide weld overlays for erosion/corrosion protection of boiler tubes in Low NOx boilers. Composite iron/aluminum wires will be used with the Gas Metal Arc Welding (GMAW) process to prepare overlays on boiler tubes steels with aluminum contents from 8 to 16wt%. The weldability of the composite wires will be evaluated as a function of chemical composition and welding parameters. The effect of overlay composition on corrosion (oxidation and sulfidation) and solid particle erosion will also be evaluated. The laboratory studies will be complemented by field exposures of both iron aluminide weld overlays and co-extruded tubing under actual boiler conditions.

  6. Hot Corrosion Studies of HVOF-Sprayed Coating on T-91 Boiler Tube Steel at Different Operating Temperatures

    NASA Astrophysics Data System (ADS)

    Bhatia, Rakesh; Singh, Hazoor; Sidhu, Buta Singh

    2013-11-01

    The aim of the present work is to investigate the usefulness of high velocity oxy fuel-sprayed 75% Cr3C2-25% (Ni-20Cr) coating to control hot corrosion of T-91 boiler tube steel at different operating temperatures viz 550, 700, and 850 °C. The deposited coatings on the substrates exhibit nearly uniform, adherent and dense microstructure with porosity less than 2%. Thermogravimetry technique is used to study the high temperature hot corrosion behavior of uncoated and coated samples. The corrosion products of the coating on the substrate are analyzed by using XRD, SEM, and FE-SEM/EDAX to reveal their microstructural and compositional features for the corrosion mechanisms. It is found that the coated specimens have shown minimum weight gain at all the operating temperatures when compared with uncoated T-91 samples. Hence, coating is effective in decreasing the corrosion rate in the given molten salt environment. Oxides and spinels of nickel-chromium may be the reason for successful resistance against hot corrosion.

  7. Arc-Sprayed Iron-Based Coatings for Erosion-Corrosion Protection of Boiler Tubes at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Pokhmurskii, Vasyl; Student, Mykhailo; Gvozdeckii, Volodymyr; Stypnutskyy, Taras; Student, Oleksandra; Wielage, Bernhard; Pokhmurska, Hanna

    2013-06-01

    Wire arc spraying is an economically attractive thermal spray process that is especially interesting for the protection of large-scale parts or constructions. This study presents the results of the development and investigation of a number of cored wires based on the Fe-Cr-Al system with minor addition of alloying elements (B, Mn, Ni, Si, Ti, Mg, etc.). The microstructure of the coatings, their electrochemical behavior, and isothermal oxidation performance over a temperature range of 20-700 °C were investigated. Erosion resistance at elevated temperatures was determined with a laboratory test unit under test conditions that have simulated the work conditions in fossil-fuel-fired boilers. It was established that the oxidation resistance and the gas-abrasive wear resistance of arc-sprayed coatings depend mostly on the coating microstructure and homogeneity of element distribution rather than on the general alloying level and microhardness of the coating. A new parameter for coating characterization, namely, the coefficient of chemical microheterogeneity, K CMH, is introduced to quantify this influence. Formation of the coating microstructure at elevated temperatures and its influence on the protection ability of the coating are discussed.

  8. Stress-Assisted Corrosion in Boiler Tubes

    SciTech Connect

    Preet M Singh; Steven J Pawel

    2006-05-27

    A number of industrial boilers, including in the pulp and paper industry, needed to replace their lower furnace tubes or decommission many recovery boilers due to stress-assisted corrosion (SAC) on the waterside of boiler tubes. More than half of the power and recovery boilers that have been inspected reveal SAC damage, which portends significant energy and economic impacts. The goal of this project was to clarify the mechanism of stress-assisted corrosion (SAC) of boiler tubes for the purpose of determining key parameters in its mitigation and control. To accomplish this in-situ strain measurements on boiler tubes were made. Boiler water environment was simulated in the laboratory and effects of water chemistry on SAC initiation and growth were evaluated in terms of industrial operations. Results from this project have shown that the dissolved oxygen is single most important factor in SAC initiation on carbon steel samples. Control of dissolved oxygen can be used to mitigate SAC in industrial boilers. Results have also shown that sharp corrosion fatigue and bulbous SAC cracks have similar mechanism but the morphology is different due to availability of oxygen during boiler shutdown conditions. Results are described in the final technical report.

  9. Microphone Detects Boiler-Tube Leaks

    NASA Technical Reports Server (NTRS)

    Parthasarathy, S. P.

    1985-01-01

    Unit simple, sensitive, rugged, and reliable. Diaphragmless microphone detects leaks from small boiler tubes. Porous plug retains carbon granules in tube while allowing pressure changes to penetrate to granules. Has greater life expectancy than previous controllers and used in variety of hot corrosive atmospheres.

  10. Digital radiographic systems detect boiler tube cracks

    SciTech Connect

    Walker, S.

    2008-06-15

    Boiler water wall leaks have been a major cause of steam plant forced outages. But conventional nondestructive evaluation techniques have a poor track record of detecting corrosion fatigue cracking on the inside surface of the cold side of waterwall tubing. EPRI is performing field trials of a prototype direct-digital radiographic system that promises to be a game changer. 8 figs.

  11. Computer simulation of the fire-tube boiler hydrodynamics

    NASA Astrophysics Data System (ADS)

    Khaustov, Sergei A.; Zavorin, Alexander S.; Buvakov, Konstantin V.; Sheikin, Vyacheslav A.

    2015-01-01

    Finite element method was used for simulating the hydrodynamics of fire-tube boiler with the ANSYS Fluent 12.1.4 engineering simulation software. Hydrodynamic structure and volumetric temperature distribution were calculated. The results are presented in graphical form. Complete geometric model of the fire-tube boiler based on boiler drawings was considered. Obtained results are suitable for qualitative analysis of hydrodynamics and singularities identification in fire-tube boiler water shell.

  12. Stress Assisted Corrosion in Boiler Tubes - Failure Analysis

    SciTech Connect

    Singh, Preet M; Pawel, Steven J; Yang, Dong; Mahmood, Jamshad

    2007-01-01

    Stress assisted corrosion (SAC) of carbon steel boiler tubes is one of the major causes of waterside failure in industrial boilers. SAC is a major concern for kraft recovery boilers in the pulp and paper industry as any water leak into the furnace can cause a smelt-water explosion in the boiler. Failed carbon steel boiler tubes from different kraft recovery boilers were examined to understand the role of carbon steel microstructure on crack initiation and SAC crack morphology. A number of carbon steel tubes showed a deep decarburized layer on the inner surface (water-touched) and also an unusually large grain size at the inner tube surface. SAC cracks were found to initiate in these areas with large-graineddecarburized microstructure. Tubes without such microstructure were also found to have SAC cracks. It was found that the decarburization and large grained microstructure may facilitate initiation and growth but is not necessary for SAC of carbon steel boiler tubes.

  13. EVALUATION OF LIME PRECIPITATION FOR TREATING BOILER TUBE CLEANING WASTES

    EPA Science Inventory

    The report gives results of an evaluation of lime precipitation for treating boiler tube cleaning wastes. In this project, wastewater samples were collected from six boiler tubeside chemical cleanings, using complexing and chelating agents. The samples represented: (1) ammoniacal...

  14. A Flexural Mode Tuning Technique for Membraned Boiler Tubing

    SciTech Connect

    Quarry, M J; Chinn, D J; Rose, J L

    2005-03-21

    Corrosion of tubing used in black-liquor recovery boilers is a major concern in all pulp and paper mills. Extensive corrosion in recovery boiler tubes can result in a significant safety and environmental hazard. Considerable plant resources are expended to inspect recovery boiler tubing. Currently, visual and ultrasonic inspections are primarily used during the annual maintenance shutdown to monitor corrosion rates and cracking of tubing. This project is developing guided acoustic waves for use on recovery boiler tubing. The feature of this acoustic technique is its cost-effectiveness in inspecting long lengths of tubes from a single inspection point. A piezoelectric or electromagnetic transducer induces guided waves into the tubes. The transducer detects fireside defects from the cold side or fireside of the tube. Cracking and thinning on recovery boiler tubes have been detected with this technique in both laboratory and field applications.

  15. Residual Strain Distribution in Bent Composite Boiler Tubes

    SciTech Connect

    Hubbard, Camden R; Gorti, Sarma B; Tang, Fei

    2006-01-01

    Kraft recovery boilers are typically constructed of carbon steel boiler tubes clad with a corrosion resistant layer, and these composite tubes are bent and welded together to form air port panels which enable the combustion air to enter the boiler. In this paper, the through-thickness residual strain in the carbon steel layer of non-heat-treated and heat-treated composite bent tubes were measured by neutron diffraction techniques and modeled by finite element modeling. The results can be used to optimize material selection and manufacturing processes to prevent stress corrosion and corrosion fatigue cracking in the boiler tubes.

  16. Corrosion fatigue boiler tube failures in waterwalls and economizers

    SciTech Connect

    McNabb, D.; Sidey, D. )

    1992-04-01

    Corrosion fatigue is a cracking mechanism initiating on the inside surface of water-touched boiler tubing at locations subject to high fatigue stresses, usually at pressure/nonpressure attachments. The mechanism is considered one of the last major sources of boiler tube failures in subcritical drum-type boilers without a root cause solution. The Electric Power Research Institute initiated a study to derive solutions to corrosion fatigue for in-service boilers and guidelines for the design of new boilers. The study consisted of a number of tasks including a survey of industry experience, field testing, theoretical stress analysis, and laboratory testing. The present volume summarizes the survey results. Ten subcritical drum-type boilers participated in the survey. The procedure involved a review of maintenance and boiler water chemistry history, and a detailed inspection of the boiler.

  17. Guided wave acoustic monitoring of corrosion in recovery boiler tubing

    SciTech Connect

    Quarry, M J; Chinn, D J

    2004-02-19

    Corrosion of tubing used in black-liquor recovery boilers is a major concern in all pulp and paper mills. Extensive corrosion in recovery boiler tubes can result in a significant safety and environmental hazard. Considerable plant resources are expended to inspect recovery boiler tubing. Currently, visual and ultrasonic inspections are primarily used during the annual maintenance shutdown to monitor corrosion rates and cracking of tubing. This Department of Energy, Office of Industrial Technologies project is developing guided acoustic waves for use on recovery boiler tubing. The feature of this acoustic technique is its cost-effectiveness in inspecting long lengths of tubes from a single inspection point. A piezoelectric or electromagnetic transducer induces guided waves into the tubes. The transducer detects fireside defects from the coldside or fireside of the tube. Cracking and thinning on recovery boiler tubes have been detected with this technique in both laboratory and field applications. This technique appears very promising for recovery boiler tube application, potentially expediting annual inspection of tube integrity.

  18. Boiler tube corrosion characterization with a scanning thermal line

    NASA Astrophysics Data System (ADS)

    Cramer, K. Elliott; Jacobstein, A. Ronald; Reilly, Thomas L.

    2001-03-01

    Wall thinning due to corrosion in utility boiler waterwall tubing is a significant operational concern for boiler operators. Historically, conventional ultrasonics has been used for inspection of these tubes. Unfortunately, ultrasonic inspection is very manpower intense and slow. Therefore, thickness measurements are typically taken over a relatively small percentage of the total boiler wall and statistical analysis is used to determine the overall condition of the boiler tubing. Other inspection techniques, such as electromagnetic acoustic transducer (EMAT), have recently been evaluated, however they provide only a qualitative evaluation - identifying areas or spots where corrosion has significantly reduced the wall thickness. NASA Langley Research Center, in cooperation with ThermTech Services, has developed a thermal NDE technique designed to quantitatively measure the wall thickness and thus determine the amount of material thinning present in steel boiler tubing. The technique involves the movement of a thermal line source across the outer surface of the tubing followed by an infrared imager at a fixed distance behind the line source. Quantitative images of the material loss due to corrosion are reconstructed from measurements of the induced surface temperature variations. This paper will present a discussion of the development of the thermal imaging system as well as the techniques used to reconstruct images of flaws. The application of the thermal line source coupled with the analysis technique represents a significant improvement in the inspection speed and accuracy for large structures such as boiler waterwalls.

  19. Composite coatings for elevated temperature erosion-corrosion protection in fossil-fueled boilers

    SciTech Connect

    Verstak, A.; Wang, B.; Baranovski, V.; Beliaev, A.

    1998-12-31

    Fluidized bed combustors components suffer severe erosion, frequently accomplished by corrosive gases attack at elevated temperatures. The tubes damage rate depends on the boiler design bed constituents and combustion parameters, however an accelerated metal wastage is usually found in the same specific areas of different boilers. New HVOF sprayed coatings are developed for the tube erosion-corrosion protection, based on Cr{sub 2}C{sub 2}/Ni-Cr, Cr-Ti-C/Ni-Cr-Mo, and Al{sub 2}O{sub 3}/NiAl composite materials. The combustion arc Fe-Cr-C coatings were found as an economical solution for relatively low erosion rate zones. The coatings properties and behavior under simulated elevated temperature erosion conditions and in the operating boilers are discussed.

  20. Development of clad boiler tubes extruded from bimetallic centrifugal castings

    SciTech Connect

    Sponseller, D.L.; Bakker, W.T.; Timmons, G.A.

    1998-04-01

    Wrought tubes of T-11 steel, externally clad with SS310, have been produced by a new method. The alloys were united directly from the molten state by centrifugal casting. In the optimum process, temperatures were controlled to prevent meltback of the SS310 outer layer by the higher melting T-11 stream. Hollow extrusion billets were prepared from the heavy-walled cast bimetallic tubes and successfully hot extruded to 84-mm OD x 64-mm ID tubes, and to 51-mm OD x 38-mm ID tubes. For the most part, thicknesses of the cladding and of the tube wall are rather uniform around the circumference and from end to end of the tubes. Hardness and tensile properties of annealed 51-mm tubes are uniform from end to end of a tube, and between tubes, and readily conform to ASTM A 213; tubes satisfy the flattening and flaring requirements of ASTM A 450. The cladding is metallurgically bonded to be base metal, as revealed by metallography, and by two tests developed for this study: a bond shear strength test and a twist test. In the latter test, rings 3.1 mm in thickness are slotted and severely twisted with a special tool. In tubes made by the optimum process, minute fissures that form adjacent to some of the pressure points during twist testing occupy just 3% of the bond-line length. Cost estimates for commercial production of 51-mm tubes via the centrifugal casting route suggest that such tubes should be considerably less expensive than conventionally clad tubes (extruded from composite billets assembled from heavy-walled wrought tubes). Such tubes should be attractive for the following applications in utility boilers: high-corrosion areas of existing coal-fired boilers, in both steam-generating tubes and superheaters; water walls, screen tubes, and superheater tubes of municipal waste-incineration boilers; future ultra super-critical boilers operating a higher temperatures and pressures; and steam-generating tubes of Syngas coolers of integrated coal gasification power plants.

  1. New software directs the fight against boiler tube failure

    SciTech Connect

    Abbott, R.C. ); Tilley, R.; Gehl, S. ); Singh, G.P.; Lamping, G.A. )

    1992-10-01

    Boiler Maintenance Workstation supplements formal prevention programs to dramatically reduce tube failure. This paper reports that boiler tube failure (BTF) is such a common experience (over 4000 occurrences are reported each year to the North American Electric Reliability Council) that plant managers have developed a variety of methods to aid tube repair and replacement. Although these methods, often ingenious, have steadily increased the speed of boiler tube failure diagnosis and repair, they may soon be obsolete. As a result of research and development by the Fossil Power Plants Department of the Electric Power Research Institute (EPRI), new software tools now are available and are proving to be effective at preventing failure and forced outages. One such software package, called the Boiler Maintenance Workstation (BMW), combines several modules to provide a foundation to help manage key BTF prevention activities. Research by EPRI and others has improved mechanistic understanding and uncovered prevention methods for nearly all types of failures. BMW provides guidance for applying newly developed NDE techniques, metallurgical analysis, quality control, welding, and water conditioning to a boiler availability improvement program.

  2. Boiler Tube Corrosion Characterization with a Scanning Thermal Line

    NASA Technical Reports Server (NTRS)

    Cramer, K. Elliott; Jacobstein, Ronald; Reilly, Thomas

    2001-01-01

    Wall thinning due to corrosion in utility boiler water wall tubing is a significant operational concern for boiler operators. Historically, conventional ultrasonics has been used for inspection of these tubes. Unfortunately, ultrasonic inspection is very manpower intense and slow. Therefore, thickness measurements are typically taken over a relatively small percentage of the total boiler wall and statistical analysis is used to determine the overall condition of the boiler tubing. Other inspection techniques, such as electromagnetic acoustic transducer (EMAT), have recently been evaluated, however they provide only a qualitative evaluation - identifying areas or spots where corrosion has significantly reduced the wall thickness. NASA Langley Research Center, in cooperation with ThermTech Services, has developed a thermal NDE technique designed to quantitatively measure the wall thickness and thus determine the amount of material thinning present in steel boiler tubing. The technique involves the movement of a thermal line source across the outer surface of the tubing followed by an infrared imager at a fixed distance behind the line source. Quantitative images of the material loss due to corrosion are reconstructed from measurements of the induced surface temperature variations. This paper will present a discussion of the development of the thermal imaging system as well as the techniques used to reconstruct images of flaws. The application of the thermal line source coupled with the analysis technique represents a significant improvement in the inspection speed and accuracy for large structures such as boiler water walls. A theoretical basis for the technique will be presented to establish the quantitative nature of the technique. Further, a dynamic calibration system will be presented for the technique that allows the extraction of thickness information from the temperature data. Additionally, the results of the application of this technology to actual water wall

  3. Analysis of composite tube cracking in recovery boiler floors

    SciTech Connect

    Keiser, J.R.; Taljat, B.; Wang, X.L.; Maziasz, P.J.; Hubbard, C.R.; Swindeman, R.W.; Singbeil, D.L.; Prescott, R.

    1996-08-01

    Cracking of co-extruded (generally identified as composite) floor tubes in kraft black liquor recovery boilers was first observed in Scandinavia, but this problem has now been found in many North American boilers. In most cases, cracking in the outer 304L stainless steel has not progressed into the carbon steel, but the potential for such crack propagation is a cause of concern. A multidimensional study has been initiated to characterize the cracking seen in composite floor tubes, to measure the residual stresses resulting from composite tube fabrication, and to predict the stresses in tubes under operating conditions. The characterization studies include review of available reports and documents on composite tube cracking, metallographic examination of a substantial number of cracked tubes, and evaluation of the dislocation structure in cracked tubes. Neutron and X-ray diffraction are being used to determine the residual stresses in composite tubes from two major manufacturers, and finite element analysis is being used to predict the stresses in the tubes during normal operation and under conditions where thermal fluctuations occur.

  4. Metallurgical Analysis of Cracks Formed on Coal Fired Boiler Tube

    NASA Astrophysics Data System (ADS)

    Kishor, Rajat; Kyada, Tushal; Goyal, Rajesh K.; Kathayat, T. S.

    2015-02-01

    Metallurgical failure analysis was carried out for cracks observed on the outer surface of a boiler tube made of ASME SA 210 GR A1 grade steel. The cracks on the surface of the tube were observed after 6 months from the installation in service. A careful visual inspection, chemical analysis, hardness measurement, detailed microstructural analysis using optical and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy were carried out to ascertain the cause for failure. Visual inspection of the failed tube revealed the presence of oxide scales and ash deposits on the surface of the tube exposed to fire. Many cracks extending longitudinally were observed on the surface of the tube. Bulging of the tube was also observed. The results of chemical analysis, hardness values and optical micrographs did not exhibit any abnormality at the region of failure. However, detailed SEM with EDS analysis confirmed the presence of various oxide scales. These scales initiated corrosion at both the inner and outer surfaces of the tube. In addition, excessive hoop stress also developed at the region of failure. It is concluded that the failure of the boiler tube took place owing to the combined effect of the corrosion caused by the oxide scales as well as the excessive hoop stress.

  5. Thermal Behavior of Floor Tubes in a Kraft Recovery Boiler

    SciTech Connect

    Barker, R.E.; Choudhury, K.A.; Gorog, J.P.; Hall, L.M.; Keiser, J.R.; Sarma, G.B.

    1999-09-12

    The temperatures of floor tubes in a slope-floored black liquor recovery boiler were measured using an array of thermocouples located on the tube crowns. It was found that sudden, short duration temperature increases occurred with a frequency that increased with distance from the spout wall. To determine if the temperature pulses were associated with material falling from the convective section of the boiler, the pattern of sootblower operation was recorded and compared with the pattern of temperature pulses. During the period from September, 1998, through February, 1999, it was found that more than 2/3 of the temperature pulses occurred during the time when one of the fast eight sootblowers, which are directed at the back of the screen tubes and the leading edge of the first superheater bank, was operating.

  6. Boiler tube failures in municipal waste-to-energy plants

    SciTech Connect

    Krause, H.H.; Wright, I.G.

    1996-01-01

    Waste-to-energy plants experienced increased boiler tube failures when the design changed from waste-heat boilers to radiant furnace waterwalls using superheat. Fireside attack by chlorine and sulfur compounds in refuse combustion products caused many forced outages in early European plants operating at high steam temperatures and pressures. Despite conservative steam conditions in the first US plants, failures occurred. As steam temperatures increased, corrosion problems multiplied. The problems have been alleviated by covering the waterwalls with either refractory or weld overlays of nickel-based alloys and using high nickel-chromium alloys for superheater tubes. Changes in furnace design to provide uniform combustion and avoid reducing conditions in the waterwall zone and to lower the gas temperature in the superheater also have helped minimize corrosion.

  7. High Temperature Behavior of Cr3C2-NiCr Coatings in the Actual Coal-Fired Boiler Environment

    NASA Astrophysics Data System (ADS)

    Bhatia, Rakesh; Sidhu, Hazoor Singh; Sidhu, Buta Singh

    2015-03-01

    Erosion-corrosion is a serious problem observed in steam-powered electricity generation plants, and industrial waste incinerators. In the present study, four compositions of Cr3C2-(Ni-20Cr) alloy coating powder were deposited by high-velocity oxy-fuel spray technique on T-91 boiler tube steel. The cyclic studies were performed in a coal-fired boiler at 1123 K ± 10 K (850 °C ± 10 °C). X-ray diffraction, scanning electron microscopy/energy dispersive X-ray analysis and elemental mapping analysis techniques were used to analyze the corrosion products. All the coatings deposited on T-91 boiler tube steel imparted hot corrosion resistance. The 65 pctCr3C2 -35 pct (Ni-20Cr)-coated T-91 steel sample performed better than all other coated samples in the given environment.

  8. High-performance nanoscale composite coatings for boiler applications

    NASA Astrophysics Data System (ADS)

    Branagan, D. J.; Breitsameter, M.; Meacham, B. E.; Belashchenko, V.

    2005-06-01

    In this article, we will show how unconventional nanoscale composite coatings can be formed using conventional wire-arc thermal spray systems. The as-sprayed SHS7170 wire-arc coatings are found to develop an amorphous matrix structure containing starburst-shaped boride and carbide crystallites with sizes ranging from 60 to 140 nm. After heating to temperatures above the peak crystalline temperature (566 °C), a solid/state transformation occurs that results in the formation of an intimate three-phase matrix structure consisting of the same complex boride and carbide phases, along with α-iron interdispersed on a structural scale from 60 to 110 nm. The nanocomposite microstructure contains clean grain boundaries, which are found to be extremely stable and resist coarsening throughout the range of temperatures found in boilers. Additionally, the properties of the coating are presented including the bond strength, hardness, bend resistance, and impact resistance. The sprayability, forgiveness, and repairability of the SHS7170 wire-arc coatings are explained in detail, with an emphasis on field applicability in boiler environments. The performance of the SHS7170 coatings in boiler environments is measured via elevated temperature-erosion experiments conducted at 300, 450, and 600 °C using bed ash from an operating circulating fluidized-bed combustor boiler, and the results are compared with those for existing boiler coatings.

  9. Evaluation of the behavior of shrouded plasma spray coatings in the platen superheater of coal-fired boilers

    SciTech Connect

    Sidhu, B.S.; Prakash, S.

    2006-06-15

    Nickel- and cobalt-based coatings were formulated by a shrouded plasma spray process on boiler tube steels, namely, ASTM-SA210-grade A1 (GrA1), ASTM-SA213-T-11 (T11), and ASTM-SA213-T-22 (T22). The Ni-22Cr-10A1-1Y alloy powder was sprayed as a bond in each case before the final coating. The degradation behavior of the bared and coated steels was studied in the platen superheater of the coal-fired boiler. The samples were inserted through the soot blower dummy points with the help of stainless steel wires. The coatings were found to be effective in increasing resistance to degradation in the given boiler environment. The maximum protection was observed in the case of Stellite-6 (St-6) coating.

  10. Development of Erosion-Corrosion-Resistant Cold-Spray Nanostructured Ni-20Cr Coating for Coal-Fired Boiler Applications

    NASA Astrophysics Data System (ADS)

    Kumar, M.; Singh, H.; Singh, N.; Chavan, N. M.; Kumar, S.; Joshi, S. V.

    2015-12-01

    The erosion-corrosion (E-C) behavior of a cold-spray nanostructured Ni-20Cr coating was studied under cyclic conditions in a coal-fired boiler. This study was done for 15 cycles (1500 h), in which each cycle comprised 100 h of heating in the boiler environment, followed by 1 h of cooling under ambient air conditions. The E-C extent was evaluated in terms of thickness loss data of the samples. The eroded-corroded samples were characterized using XRD, SEM/EDS, and x-ray mapping analyses. The nanostructured coating offered excellent E-C protection to boiler tube material (SA 516 steel) under harsh live conditions of the boiler. This E-C resistance offered by investigated coating may be attributed to the presence of protective NiO and Cr2O3 phases in its oxide scale and its superior as-sprayed microhardness.

  11. Corrosion fatigue boiler tube failures in waterwalls and economizers. Volume 1, Field Survey Summary: Final report

    SciTech Connect

    McNabb, D.; Sidey, D.

    1992-04-01

    Corrosion fatigue is a cracking mechanism initiating on the inside surface of water-touched boiler tubing at locations subject to high fatigue stresses, usually at pressure/nonpressure attachments. The mechanism is considered one of the last major sources of boiler tube failures in subcritical drum-type boilers without a root cause solution. The Electric Power Research Institute initiated a study to derive solutions to corrosion fatigue for in-service boilers and guidelines for the design of new boilers. The study consisted of a number of tasks including a survey of industry experience, field testing, theoretical stress analysis, and laboratory testing. The present volume summarizes the survey results. Ten subcritical drum-type boilers participated in the survey. The procedure involved a review of maintenance and boiler water chemistry history, and a detailed inspection of the boiler.

  12. Final Report: Guided Acoustic Wave Monitoring of Corrosion in Recovery Boiler Tubing

    SciTech Connect

    Chinn, D J; Quarry, M J; Rose, J L

    2005-03-31

    Corrosion of tubing used in black-liquor recovery boilers is a major concern in all pulp and paper mills. Extensive corrosion in recovery boiler tubes can result in a significant safety and environmental hazard. Considerable plant resources are expended to inspect recovery boiler tubing. Currently, visual and ultrasonic inspections are primarily used during the annual maintenance shutdown to monitor corrosion rates and cracking of tubing. This Department of Energy, Office of Industrial Technologies project is developing guided acoustic waves for use on recovery boiler tubing. The feature of this acoustic technique is its cost-effectiveness in inspecting long lengths of tubes from a single inspection point. A piezoelectric or electromagnetic transducer induces guided waves into the tubes. The transducer detects fireside defects from the cold side or fireside of the tube. Cracking and thinning on recovery boiler tubes have been detected with this technique in both laboratory and field applications. This technique appears very promising for recovery boiler tube application, potentially expediting annual inspection of tube integrity.

  13. Investigations on the Behavior of HVOF and Cold Sprayed Ni-20Cr Coating on T22 Boiler Steel in Actual Boiler Environment

    NASA Astrophysics Data System (ADS)

    Bala, Niraj; Singh, Harpreet; Prakash, Satya; Karthikeyan, J.

    2012-01-01

    High temperature corrosion accompanied by erosion is a severe problem, which may result in premature failure of the boiler tubes. One countermeasure to overcome this problem is the use of thermal spray protective coatings. In the current investigation high velocity oxy-fuel (HVOF) and cold spray processes have been used to deposit commercial Ni-20Cr powder on T22 boiler steel. To evaluate the performance of the coatings in actual conditions the bare as well as the coated steels were subjected to cyclic exposures, in the superheater zone of a coal fired boiler for 15 cycles. The weight change and thickness loss data were used to establish kinetics of the erosion-corrosion. X-ray diffraction, surface and cross-sectional field emission scanning electron microscope/energy dispersive spectroscopy (FE-SEM/EDS) and x-ray mapping techniques were used to analyse the as-sprayed and corroded specimens. The HVOF sprayed coating performed better than its cold sprayed counterpart in actual boiler environment.

  14. Sensing system for detection and control of deposition on pendant tubes in recovery and power boilers

    DOEpatents

    Kychakoff, George; Afromowitz, Martin A; Hugle, Richard E

    2005-06-21

    A system for detection and control of deposition on pendant tubes in recovery and power boilers includes one or more deposit monitoring sensors operating in infrared regions and about 4 or 8.7 microns and directly producing images of the interior of the boiler. An image pre-processing circuit (95) in which a 2-D image formed by the video data input is captured, and includes a low pass filter for performing noise filtering of said video input. An image segmentation module (105) for separating the image of the recovery boiler interior into background, pendant tubes, and deposition. An image-understanding unit (115) matches derived regions to a 3-D model of said boiler. It derives a 3-D structure the deposition on pendant tubes in the boiler and provides the information about deposits to the plant distributed control system (130) for more efficient operation of the plant pendant tube cleaning and operating systems.

  15. Composite tube cracking in kraft recovery boilers: A state-of-the-art review

    SciTech Connect

    Singbeil, D.L.; Prescott, R.; Keiser, J.R.; Swindeman, R.W.

    1997-07-01

    Beginning in the mid-1960s, increasing energy costs in Finland and Sweden made energy recovery more critical to the cost-effective operation of a kraft pulp mill. Boiler designers responded to this need by raising the steam operating pressure, but almost immediately the wall tubes in these new boilers began to corrode rapidly. Test panels installed in the walls of the most severely corroding boiler identified austenitic stainless steel as sufficiently resistant to the new corrosive conditions, and discussions with Sandvik AB, a Swedish tube manufacturer, led to the suggestion that coextruded tubes be used for water wall service in kraft recovery boilers. Replacement of carbon steel by coextruded tubes has solved most of the corrosion problems experienced by carbon steel wall tubes, however, these tubes have not been problem-free. Beginning in early 1995, a multidisciplinary research program funded by the US Department of Energy was established to investigate the cause of cracking in coextruded tubes and to develop improved materials for use in water walls and floors of kraft recovery boilers. One portion of that program, a state-of-the-art review of public- and private-domain documents related to coextruded tube cracking in kraft recovery boilers is reported here. Sources of information that were consulted for this review include the following: tube manufacturers, boiler manufacturers, public-domain literature, companies operating kraft recovery boilers, consultants and failure analysis laboratories, and failure analyses conducted specifically for this project. Much of the information contained in this report involves cracking problems experienced in recovery boiler floors and those aspects of spout and air-port-opening cracking not readily attributable to thermal fatigue. 61 refs.

  16. The use of laser-induced plasma spectroscopy technique for the characterization of boiler tubes

    NASA Astrophysics Data System (ADS)

    Nicolas, G.; Mateo, M. P.; Yañez, A.

    2007-12-01

    The present work focuses on the characterization of boiler tube walls using laser-induced plasma spectroscopy technique with visual inspection by optical and scanning electron microscopy of the cross-sections of these tubes. In a watertube boiler, water runs through tubes that are surrounded by a heating source. As a result, the water is heated to very high temperatures, causing accumulation of deposits on the inside surfaces of the tubes. These deposits play an important role in the efficiency of the boiler tube because they produce a reduction of the boiler heat rate and an increase in the number of tube failures. The objectives are to determine the thickness and arrangement of deposits located on the highest heat area of the boiler and compare them with tube parts where the heat flux is lower. The major deposits found were copper and magnetite. These deposits come mainly from the boiler feedwater and from the reaction between iron and water, and they do not form on the tube walls at a uniform rate over time. Their amount depends on the areas where they are collected. A Nd:YAG laser operating at 355 nm has been used to perform laser-induced plasma spectra and depth profiles of the deposits.

  17. Development of composite tube protective coatings

    NASA Technical Reports Server (NTRS)

    Dursch, H.; Hendricks, C.

    1986-01-01

    Protective coatings for graphite/epoxy (Gr/Ep) tubular structures proposed for the Space Station are evaluated. The program was divided into four parts; System Definition, Coating Concept Selection and Evaluation, Scale-up and Assembly, and Reporting. System Definition involved defining the structural and environmental properties required of the Gr/Ep tubes. The prepreg and ply sequence selected was a P75S/934 (O2, + or - 20, O2)sub s layup which meets the various structural requirements of the Space Station. Coating Concept and Selection comprised the main emphasis of the effort. Concepts for protectively coating the Gr/Ep tubes included the use of metal foil and electroplating. The program results demonstrated that both phosphoric and chromic acid anodized Al foil provided adequate adhesion to the Gr/Ep tubes and stability of optical properties when subjected to atomic oxygen and thermal cycling representative of the LEO environment. SiO2/Al coatings sputtered onto Al foils also resulted in an excellent protective coating. The electroplated Ni possessed unacceptable adhesion loss to the Gr/Ep tubes during atomic oxygen testing. Scale-Up and Assembly involved fabricating and wrapping 8-ft-long by 2-in-diameter Gr/EP tubes with chromic acid anodized foil and delivering these tubes, along with representative Space Station erectable end fittings, to NASA LaRC.

  18. The application of tubes produced by the electroslag melting process in tubing of thermal power plants and boilers

    NASA Astrophysics Data System (ADS)

    Nemykina, T. I.; Koz'minskii, A. N.

    2013-06-01

    The results of a chemical analysis to determine the short-term mechanical and metallographic properties of boiler tubes manufactured by the electroslag melting process are presented. The paper also contains the data on the long-term strength of the above tubes.

  19. Designing a magnetoacoustic emission measurement configuration for measurement of creep damage in power plant boiler tubes

    NASA Astrophysics Data System (ADS)

    Augustyniak, B.; Chmielewski, M.; Piotrowski, L.; Sablik, M. J.

    2002-05-01

    We discuss design features that are needed for magnetoacoustic emission (MAE) measurement of creep damage in the outer walls of boiler tubes. MAE is used because it decreases monotonically with increasing creep damage. Features of magnet design for boiler tube inspection are presented. Relationship of total MAE to Barkhausen noise path integrals is discussed. Also, dependence of MAE on frequency and tube wall thickness is delineated. Finally, measurements are discussed which show how azimuthal asymmetry in creep damage is echoed in azimuthal asymmetry in MAE. All tests were performed on 2Cr-1Mo Polish steel tube specimens.

  20. Mechanical Design of Steel Tubing for Use in Black Liquor Recovery Boilers

    SciTech Connect

    Taljat, B.; Zacharaia, T.; Wang, X.; Kesier, J.; Swindeman, R.; Hubbard, C.

    1999-05-26

    Finite element models were developed for thermal-mechanical analysis of black liquor recovery boiler floor tubes. Residual stresses in boiler floors due to various manufacturing processes were analyzed. The modeling results were verified by X-ray and neutron diffraction measurements at room temperature on as-manufactured tubes as well as tubes after service. The established finite element models were then used to evaluate stress conditions during boiler operation. Using these finite element models, a parametric response surface study was performed to investigate the influence of material properties of the clad layer on stresses in the floor tubes during various boiler operating conditions, which yielded a generalized solution of stresses in the composite tube floors. The results of the study are useful for identifying the mechanisms of cracking experienced by recovery boilers. Based on the results of the response surface study, a recommendation was made for more suitable materials in terms of the analyzed mechanical properties. Alternative materials and manufacturing processes are being considered to improve the resistance to cracking and the in-service life of composite tubes. To avoid numerous FE stress-strain analyses of composite tubes made of different material combinations, a response surface study was performed that considered two essential mechanical properties of the clad material - coefficient of thermal expansion and yield stress - as independent variables. The response surface study provided a generalized solution of stresses in the floor in terms of the two selected parameters.

  1. Dynamic air deposited coatings for power and black liquor recovery boilers

    SciTech Connect

    Verstak, A.A.; Baranovski, V.E.

    1999-11-01

    Dynamic Air Deposition (DyAir) is a novel coating method designed to protect the tubing of power and black liquor recovery boilers against corrosion attack at elevated temperatures. The method utilizes the energy of combustion of gaseous fuel and air to heat the powder material to a temperature just below its melting point and accelerate it over 600 m/s to form a coating. The Ni-Cr and Ni-Cr-Mo DyAir coatings revealed no gas permeability and extremely low oxygen content. Compared to the electric arc and HVOF-sprayed coatings, the DyAir coatings exhibited higher hardness and better crack resistance. During aging at 400 and 700 C the bond strength and crack resistance of the DyAir coatings increased dramatically due to intensive diffusion processes in absence of internal corrosion attack. The DyAir coatings revealed outstanding resistance to corrosion, such as sulfidation attack in presence of hydrochloric acid gas at 400 C, oxidation attack at 700 C and oxidation attack in presence of chlorine at 400 C.

  2. The Characterization of Twin-Wire Arc-Sprayed FeCrBSi Coating and the Application in Sewage Sludge Boilers

    NASA Astrophysics Data System (ADS)

    Qin, Enwei; Huang, Qian; Shao, Yumin; Chen, Guoxing; Ye, Lin; Gu, Qin; Wu, Shuhui

    2014-12-01

    Incineration in boilers is an environment-friendly treatment for industrial and civil sewage sludge. However, due to the aggressive nature of the sludge, the boiler fireside-surface is subjected to severe wear, erosive, and high temperature corrosion problems during incineration. In this study, we developed an economical FeCrBSi wire material with iron weight content as high as 80%. The coating was prepared by twin-wire arc spraying processing. The chemical compositions of the coating, as well as phase components were analyzed by energy-dispersive spectroscopy and x-ray diffraction method. The surface roughness, porosity, and cross-sectional morphology were further characterized. The coating hardness is close to that of the commercial Armacor M and Armacor C materials. In-boiler test was also carried out. The low thickness loss of the tube indicates a promising application future in sludge boilers.

  3. The Characterization of Twin-Wire Arc-Sprayed FeCrBSi Coating and the Application in Sewage Sludge Boilers

    NASA Astrophysics Data System (ADS)

    Qin, Enwei; Huang, Qian; Shao, Yumin; Chen, Guoxing; Ye, Lin; Gu, Qin; Wu, Shuhui

    2014-09-01

    Incineration in boilers is an environment-friendly treatment for industrial and civil sewage sludge. However, due to the aggressive nature of the sludge, the boiler fireside-surface is subjected to severe wear, erosive, and high temperature corrosion problems during incineration. In this study, we developed an economical FeCrBSi wire material with iron weight content as high as 80%. The coating was prepared by twin-wire arc spraying processing. The chemical compositions of the coating, as well as phase components were analyzed by energy-dispersive spectroscopy and x-ray diffraction method. The surface roughness, porosity, and cross-sectional morphology were further characterized. The coating hardness is close to that of the commercial Armacor M and Armacor C materials. In-boiler test was also carried out. The low thickness loss of the tube indicates a promising application future in sludge boilers.

  4. Erosion-corrosion of as-plasma-sprayed and laser-remelted NiCrAlY bond coats in working conditions of a coal-fired boiler

    SciTech Connect

    Sidhu, B.S.; Prakash, S.

    2008-01-15

    Ni-22Cr-10Al-1Y plasma spray coating has been formulated on boiler tube steels. namely, low-carbon steel ASTM SA210-Grade A1. 1Cr-0.5Mo steel ASTM SA213-T-11, and 2.25Cr-1Mo steel ASTM SA213-T-22. The coated steels also have been laser-remelted using a Nd:YAG laser. The degradation behavior of as-sprayed and laser-remelted coatings have been evaluated in actual conditions in a coal-fired boiler for 1,000 h at 755{sup o}C. The laser remelting has been found to be effective to increase the degradation resistance of plasma-sprayed boiler steels. ASTM SA213-T-22-coated and laser-remelted steel has proved to be most effective in resistance to degrading species.

  5. Analysis of cracking of co-extruded recovery boiler floor tubes

    SciTech Connect

    Keiser, J.R.; Taljat, B.; Wang, X.L.

    1997-08-01

    Cracking of the stainless steel layer in co-extruded 304L/SA210 tubing used in black liquor recovery boilers is being found in an ever-increasing number of North American pulp and paper mills. Because of the possibility of a tube failure, this is a significant safety issue, and, because of the extra time required for tube inspection and repair, this can become an economic issue as well. In a project funded by the U.S. Department of Energy and given wide support among paper companies, boiler manufacturers, and tube fabricators, studies are being conducted to determine the cause of the cracking and to identify alternate materials and/or operating procedures to prevent tube cracking. Examination of cracked tubes has permitted characterization of crack features, and transmission electron microscopy is providing information about the thermal history, particularly cyclic thermal exposures, that tubes have experienced. Neutron and x-ray diffraction techniques are being used to determine the residual stresses in as-fabricated tube panels and exposed tubes, and finite element modeling is providing information about the stresses the tubes experience during operation. Laboratory studies are being conducted to determine the susceptibility of the co-extruded 304L/SA210 tubes to stress corrosion cracking, thermal fatigue, and corrosion in molten smelt. This paper presents the current status of these studies. On the basis of all of these studies, recommendations for means to prevent tube cracking will be offered.

  6. Investigation into Cause of High Temperature Failure of Boiler Superheater Tube

    NASA Astrophysics Data System (ADS)

    Ghosh, D.; Ray, S.; Roy, H.; Shukla, A. K.

    2015-04-01

    The failure of the boiler tubes occur due to various reasons like creep, fatigue, corrosion and erosion. This paper highlights a case study of typical premature failure of a final superheater tube of 210 MW thermal power plant boiler. Visual examination, dimensional measurement, chemical analysis, oxide scale thickness measurement, microstructural examination are conducted as part of the investigations. Apart from these investigations, sulfur print, Energy Dispersive spectroscopy (EDS) and X ray diffraction analysis (XRD) are also conducted to ascertain the probable cause of failure of final super heater tube. Finally it has been concluded that the premature failure of the super heater tube can be attributed to the combination of localized high tube metal temperature and loss of metal from the outer surface due to high temperature corrosion. The corrective actions have also been suggested to avoid this type of failure in near future.

  7. Corrosion of boiler tube alloys in refuse firing: Shredded vs bulk refuse

    SciTech Connect

    Krause, H.H. ); Daniel, P.L.; Blue, J.D. )

    1994-08-01

    Results of corrosion probe exposures at two mass burning incinerators were compared with those conducted in a unit burning refuse-derived fuel. Tests were conducted with carbon steel, low-alloy steels, stainless steels, and high nickel-chromium alloys. Corrosion rates at similar metal and gas temperatures were essentially the same for both types of fuel. Boiler tube performance in the waterwalls of other incinerators confirmed these results. Boiler design and operating conditions appear to be more important factors in tube wastage than the extent of refuse processing.

  8. Sensing system for detection and control of deposition on pendant tubes in recovery and power boilers

    DOEpatents

    Kychakoff, George; Afromowitz, Martin A.; Hogle, Richard E.

    2008-10-14

    A system for detection and control of deposition on pendant tubes in recovery and power boilers includes one or more deposit monitoring sensors operating in infrared regions of about 4 or 8.7 microns and directly producing images of the interior of the boiler, or producing feeding signals to a data processing system for information to enable a distributed control system by which the boilers are operated to operate said boilers more efficiently. The data processing system includes an image pre-processing circuit in which a 2-D image formed by the video data input is captured, and includes a low pass filter for performing noise filtering of said video input. It also includes an image compensation system for array compensation to correct for pixel variation and dead cells, etc., and for correcting geometric distortion. An image segmentation module receives a cleaned image from the image pre-processing circuit for separating the image of the recovery boiler interior into background, pendant tubes, and deposition. It also accomplishes thresholding/clustering on gray scale/texture and makes morphological transforms to smooth regions, and identifies regions by connected components. An image-understanding unit receives a segmented image sent from the image segmentation module and matches derived regions to a 3-D model of said boiler. It derives a 3-D structure the deposition on pendant tubes in the boiler and provides the information about deposits to the plant distributed control system for more efficient operation of the plant pendant tube cleaning and operating systems.

  9. Development of clad boiler tubes extruded from bimetallic centrifugal castings

    NASA Astrophysics Data System (ADS)

    Sponseller, D. L.; Timmons, G. A.; Bakker, W. T.

    1998-04-01

    Wrought tubes of T-11 steel, externally clad with SS310, have been produced by a new method (U.S. Patent 5,558,150). The alloys were united directly from the molten state by centrifugal casting. In the optimum process, temperatures were controlled to prevent meltback of the SS310 outer layer by the higher melting T-11 stream. Hollow extrusion billets were prepared from the heavy-walled cast bimetallic tubes and successfully hot extruded (at a ratio of 13.4) to 84-mm (3.3 in.) OD X 64-mm (2.5-in.) ID tubes, and (at a ratio of 37.6) to 51-mm (2-in.) OD X 38-mm (1.5-in.) ID tubes. In all, 10 castings were produced, and 12 billets were extruded to tubes. For the most part, thicknesses of the cladding and of the tube wall are rather uniform around the circumference and from end to end of the tubes. Hardness and tensile properties of annealed 51-mm (2-in.) tubes are uniform from end to end of a tube, and between tubes, and readily conform to ASTM A 213; tubes satisfy the flattening and flaring requirements of ASTM A 450. The cladding is metallurgically bonded to the base metal, as revealed by metallography, and by two tests developed for this study: a bond shear strength test and a twist test. In the latter test, rings 3.1 mm (0.125 in.) in thickness are slotted and severely twisted with a special tool. In tubes made by the optimum process, minute fissures that form adjacent to some of the pressure points during twist testing occupy just 3 % of the bond-line length. Cost estimates for commercial production of 51-mm (2-in.) tubes via the centrifugal casting route suggest that such tubes should be considerably less expensive than conventionally clad tubes (extruded from composite billets assembled from heavy-walled wrought tubes).

  10. A study of LNCFS III coal burners on boiler waterwall tube wastage

    SciTech Connect

    Abbott, R.C.; Gordon, C.M.; Saunders, M.M.; Bray, A.J.

    1996-07-01

    Ultrasonic Testing (UT) of waterwall tubing of a tangentially-fired, sub-critical boiler at Milliken Station of New York State Electric and Gas (NYSEG) was undertaken to determine the effects of the newly installed low NO{sub x} firing system on waterwall tube wastage. During a 1993 outage, the pulverized coal-fired boiler was equipped with an ABB CE Low NO, Concentric Firing System (LNCFS) of the third generation (III) including Staged Overfire Air (SOFA) and a coal pulverizing system capable of improving mill fineness by approximately 30 percent. The study was in conjunction with a Department of Energy Clean Coal Demonstration Project. Three separate thickness, surveys were compared using the Electric Power Research Institute`s (EPRI) Boiler Maintenance Workstation (BMW). The Tube Condition Module of BMW compared a total of 20,556 test locations of the three surveys. The evaluations of the surveys indicate that the short-term effect of low NO{sub x} firing with LNCFS III and increased fineness has moderately reduced the remaining life of the carbon steel boiler tubing in selected locations of the waterfall. Approximately 5 percent of the test locations are experiencing an annual tube wastage of 0.008 inches or greater. Additional testing and analyses are recommended to better understand the longer term effects of the low NO{sub x} firing system and the wastage of selected tubing The influence of boiler operating parameters, such as cyclic duty, proportioning of secondary air, or fuel changes, on waterwall tube wastage should also be evaluated over a longer operating period.

  11. Corrosion-resistant tube materials for extended life of openings in recovery boilers

    SciTech Connect

    Paul, L.D.; Danielson, M.J.; Harper, S.L. . Research and Development Div.); Barna, J.L. . Fossil Power Div.)

    1993-08-01

    The corrosive conditions causing rapid corrosion of Type 304L stainless steel in tube openings have been duplicated in the laboratory. Alternate materials also have been tested, and some show improved corrosion resistance over Type 304L. Alloy 825 and Alloy 625 composite tubing and Alloy 600 and Alloy 625 weld overlay materials all show promise as a replacement for Type 304L in tube openings. All recovery boilers designed or operated at 8.375 MPa (1,200 psi) and above should consider using these replacement materials for tube openings.

  12. Performance of high-velocity oxy-fuel-sprayed chromium carbide-nickel chromium coating in an actual boiler environment of a thermal power plant

    SciTech Connect

    Sidhu, T.S.; Prakash, S.; Agrawal, R.D.

    2007-09-15

    The present study aims to evaluate the performance of a high-velocity oxy-fuel (HVOF)-sprayed Cr{sub 3}C{sub 2}-NiCr (chromium carbide-nickel chromium) coating on a nickel-based super-alloy in an actual industrial environment of a coal-fired boiler, with the objective to protect the boiler super-heater and reheater tubes from hot corrosion. The tests were performed in the platen super heater zone of a coal-fired boiler for 1,000 h at 900 degrees C under cyclic conditions. The Cr{sub 3}C{sub 2}-NiCr coating imparted the necessary protection to the nickel-based super alloy in the given environment. The dense and flat splat structure of the coating, and the formation of oxides of chromium and nickel and their spinels, might have protected the substrate super alloy from the inward permeation of corrosive species.

  13. Dynamic instabilities in radiation-heated boiler tubes for solar central receivers

    NASA Astrophysics Data System (ADS)

    Wolf, S.; Chan, K. C.; Chen, K.; Yadigaroglu, G.

    1982-11-01

    Density-wave instabilities have been investigated in circumferentially nonuniform radiation-heated boiler tubes, simulating solar heating. Analysis and experimental data are presented. The analysis provides the basis for a computer code, STEAMFREQ-I, for the prediction of density-wave instabilities in boiler tubes with imposed heat flux. The key model features include a drift-flux flow model in the boiling region, spatial variation of heat flux, wall dynamics, and variable steam properties in the superheat region. The experimental data include results from two radiation heated boiler panel tests. The data are applicable to central receivers for solar electric power plants. Data for stable and unstable conditions are compared with predictions from STEAMFREQ-I.

  14. Thermal Nondestructive Characterization of Corrosion in Boiler Tubes by Application fo a Moving Line Heat Source

    NASA Technical Reports Server (NTRS)

    Cramer, K. Elliott; Winfree, William P.

    2000-01-01

    Wall thinning in utility boiler waterwall tubing is a significant inspection concern for boiler operators. Historically, conventional ultrasonics has been used lor inspection of these tubes. This technique has proved to be very labor intensive and slow. This has resulted in a "spot check" approach to inspections, making thickness measurements over a relatively small percentage of the total boiler wall area. NASA Langley Research Center has developed a thermal NDE technique designed to image and quantitatively characterize the amount of material thinning present in steel tubing. The technique involves the movement of a thermal line source across the outer surface of the tubing followed by an infrared imager at a fixed distance behind the line source. Quantitative images of the material loss due to corrosion are reconstructed from measurements of the induced surface temperature variations. This paper will present a discussion of the development of the thermal imaging system as well as the techniques used to reconstruct images of flaws. The application of the thermal line source, coupled with this analysis technique, represents a significant improvement in the inspection speed for large structures such as boiler waterwalls while still providing high-resolution thickness measurements. A theoretical basis for the technique will be presented thus demonstrating the quantitative nature of the technique. Further, results of laboratory experiments on flat Panel specimens with fabricated material loss regions will be presented.

  15. MANAGING OXIDE SCALE EXFOLIATION IN BOILERS WITH TP347H SUPERHEATER TUBES

    SciTech Connect

    Sabau, Adrian S; Wright, Ian G.; Shingledecker, John P.; Tortorelli, Peter F

    2014-01-01

    A model based on a concept of fraction of exfoliated area as a function of oxide scale strain energy was developed to predict the extent of exfoliation of steam-side scale from boiler tube superheater loops. As compared with the Armitt diagram, which can be used to predict when scale damage and exfoliation would be likely to occur, a fraction of exfoliated area approach provides an estimation of mass of scale released and the fraction of tube likely to be blocked by the exfoliation. This paper show results for the extent of blockage expected in a single bend of a superheater loop was predicted as a function of operating time, bend geometry, and outlet steam temperature under realistic service conditions that include outages. The deposits of exfoliated scale were assumed to be distributed horizontally the tubes bends. Three types of bends were considered: regular bends, short bends, and hairpin bends. The progressive increase in steam and tube temperatures along a single loop of superheater tubing and the ensuing variation of oxide scale thickness are considered. Numerical simulation results for a superheater loop made of TP347H austenitic steel indicated that tube blockage fractions larger than 50% are likely to occur within the first two years of boiler operation (with regularly scheduled outages) for outlet tube temperatures of 540-570oC, which is consistent with practical experience. Higher blockage fractions were predicted for tubes with short bends and hairpin bends than for tubes with regular bends, of length that are larger than five internal tube diameters. Finally, the blockage model presented can be used with some confidence to devise operating schedules for managing the consequences of oxide scale exfoliation based on projections of time to some critical blockage fraction for specific boiler operating conditions.

  16. Overview of the DOE studies of recovery boiler floor tube cracking

    SciTech Connect

    Keiser, J.R.; Taljat, B.; Wang, X.L.

    1998-03-01

    Cracking of the stainless steel layer of coextruded 304L/SA210 recovery boiler floor tubes has been observed in an increasing number of black liquor recovery boilers. Because failure of such tubes is a serious safety concern as well as an economic issue, this project was initiated with the objective of identifying alternate materials or process changes that would prevent tube cracking. Tensile stresses are essential for the most likely failure mechanisms, i.e., fatigue or stress corrosion cracking, therefore stresses were measured at room temperature and modeling was used to predict stresses under operating conditions. Laboratory studies have identified conditions under which composite tubes crack due to thermal fatigue and stress corrosion. Floor tube temperature measurements have defined the magnitude and frequency of temperature fluctuations experienced by such tubes, and smelt corrosion studies have measured the degradation rate when molten smelt comes in contact with tubes. Based on these observations, certain materials appear more likely to resist cracking and certain process changes should help avoid conditions that cause composite tube cracking.

  17. Field experience and performance summary using the EPRI EMAT-based gaging system for boiler tubing

    SciTech Connect

    Schlader, D.; Stevens, D.; Nakoneczny, G.; Tilley, R.

    1996-07-01

    The Electric Power Research Institute (EPRI) and the Babcock & Wilcox (B&W) Company have developed a boiler tube thickness gage using EMATs (Electromagnetic Acoustic Transducers) which can be used in either a spot measuring or a scanning mode to identify localized wall thinning due to corrosion or erosion. A field-hardened, prototype version has been constructed and tested in a wide range of utility boilers. The prototype has been refined into a commercial grade system that is being utilized by B&W to supply services to utilities. This paper describes the EMAT gaging system and presents results of field applications in utility boilers. The EMAT system in its current configuration is capable of measuring tube wall thickness as thin as 0.070 inches with an accuracy comparable to conventional ultrasonic measurements, {+-}0.005 inches. Thickness readings can be obtained on tube wall surfaces which have been sandblasted or ground free of scale, and on tube wall surfaces which have uniform layers of scale. The presence of scale, in some instances, can greatly enhance the ultrasonic signal strength, allowing thickness measurements on tubes without any surface preparation as long as the scale layer is uniform.

  18. Modelling of thermal behaviour of iron oxide layers on boiler tubes

    NASA Astrophysics Data System (ADS)

    Angelo, J. D.; Bennecer, A.; Kaczmarczyk, S.; Picton, P.

    2016-05-01

    Slender boiler tubes are subject to localised swelling when they are expose to excessive heat. The latter is due to the formation of an oxide layer, which acts as an insulation barrier. This excessive heat can lead to microstructural changes in the material that would reduce the mechanical strength and would eventually lead to critical and catastrophic failure. Detecting such creep damage remains a formidable challenge for boiler operators. It involves a costly process of shutting down the plant, performing electromagnetic and ultrasonic non-destructive inspection, repairing or replacing damaged tubes and finally restarting the plant to resume its service. This research explores through a model developed using a finite element computer simulation platform the thermal behaviour of slender tubes under constant temperature exceeding 723 °K. Our simulation results demonstrate that hematite layers up to 15 μm thickness inside the tubes do not act as insulation. They clearly show the process of long term overheating on the outside of boiler tubes which in turn leads to initiation of flaws.

  19. Creep-Rupture Behavior and Recrystallization in Cold-Bent Boiler Tubing for USC Applications

    SciTech Connect

    Shingledecker, John P

    2008-01-01

    Creep-rupture experiments were conducted on candidate Ultrasupercritical (USC) alloy tubes to evaluate the effects of cold-work and recrystallization during high-temperature service. These creep tests were performed by internally pressurizing cold-bent boiler tubes at 775 C for times up to 8000 hours. The bends were fabricated with cold-work levels beyond the current ASME Boiler and Pressure Vessel (ASME B&PV) Code Section I limits for austenitic stainless steels. Destructive metallographic evaluation of the crept tube bends was used to determine the effects of cold-work and the degree of recrystallization. The metallographic analysis combined with an evaluation of the creep and rupture data suggest that solid-solution strengthened nickel-based alloys can be fabricated for high-temperature service at USC conditions utilizing levels of cold-work higher than the current allowed levels for austenitic stainless steels.

  20. Computer simulation of vortex combustion processes in fire-tube boilers

    NASA Astrophysics Data System (ADS)

    Khaustov, Sergei A.; Zavorin, Alexander S.; Buvakov, Konstantin V.; Kudryashova, Lidiya D.; Tshelkunova, Anastasiya V.

    2015-01-01

    The article describes computer simulation of the turbulent methane-air combustion in a fire-tube boiler furnace. Computer simulations performed for variants of once-through fire-tube furnace and reversive flame furnace. Options with various twist parameters of the fuel-air jet were examined. The flame structure has been determined computationally, contours of average speed, temperature and concentrations have been acquired. The results of calculations are presented in graphical form. Dependence of construction characteristics on vortex aerodynamic parameters was estimated. Turbulent combustion of natural gas in the reverse flame of fire-tube boiler was studied by means of the ANSYS Fluent 12.1.4 engineering simulation software.

  1. Resistance of Coatings for Boiler Components of Waste-to-Energy Plants to Salt Melts Containing Copper Compounds

    NASA Astrophysics Data System (ADS)

    Galetz, Mathias Christian; Bauer, Johannes Thomas; Schütze, Michael; Noguchi, Manabu; Cho, Hiromitsu

    2013-06-01

    The accelerating effect of heavy metal compounds on the corrosive attack of boiler components like superheaters poses a severe problem in modern waste-to-energy plants (WTPs). Coatings are a possible solution to protect cheap, low alloyed steel substrates from heavy metal chloride and sulfate salts, which have a relatively low melting point. These salts dissolve many alloys, and therefore often are the limiting factor as far as the lifetime of superheater tubes is concerned. In this work the corrosion performance under artificial salt deposits of different coatings, manufactured by overlay welding, thermal spraying of self-fluxing as well as conventional systems was investigated. The results of our studies clearly demonstrate the importance of alloying elements such as molybdenum or silicon. Additionally, the coatings have to be dense and of a certain thickness in order to resist the corrosive attack under these severe conditions.

  2. Application of High Temperature Corrosion-Resistant Materials and Coatings Under Severe Corrosive Environment in Waste-to-Energy Boilers

    NASA Astrophysics Data System (ADS)

    Kawahara, Yuuzou

    2007-06-01

    Corrosion-resistant materials (CRMs) and coatings are key technologies to increase power generation efficiency and reduce maintenance in waste-to-energy (WTE) plants. Corrosion environment became severe as steam temperatures have increased. The steam condition of more than 400 °C/3.9 MPa became possible in WTE boilers by using highly durable corrosion-resistant coatings, such as thermal spray of Al/80Ni20Cr alloy, HVOF-sprayed NiCrSiB alloy, Alloy 625 weld overlay for waterwall tubes and also superheater tubes. Also, the use of 310S type stainless steels and high Cr-high Mo-Ni base and high Si-Cr-Ni-Fe alloys have progressed because of a better understanding of corrosion mechanisms. Furthermore, high durability coatings using cermet and ceramic materials were applied to high temperature superheaters. This paper describes the major developments and the application of CRMs and coating technologies in the last 30 years in WTE plants, the corrosion mechanisms of alloys, the deterioration mechanisms of spray coating layers, and future subjects for the development of corrosion-resistant materials and coatings.

  3. A Novel Low-Temperature Fiffusion Aluminide Coating for Ultrasupercritical Coal-Fried Boiler Applications

    SciTech Connect

    Zhang, Ying

    2009-12-31

    An ultrasupercritical (USC) boiler with higher steam temperature and pressure is expected to increase the efficiency of the coal-fired power plant and also decrease emissions of air pollutants. Ferritic/martensitic alloys have been developed with good creep strength for the key components in coal-fired USC plants. However, they typically suffer excessive steam-side oxidation, which contributes to one of main degradation mechanisms along with the fire-side corrosion in coal-fired boilers. As the steam temperature further increases in USC boilers, oxidation of the tube internals becomes an increasing concern, and protective coatings such as aluminide-based diffusion coatings need to be considered. However, conventional aluminizing processes via pack cementation or chemical vapor deposition are typically carried out at elevated temperatures (1000-1150 C). Thermochemical treatment of ferritic/martensitic alloys at such high temperatures could severely degrade their mechanical properties, particularly the alloy's creep resistance. The research focus of this project was to develop an aluminide coating with good oxidation resistance at temperatures {le} 700 C so that the coating processing would not detrimentally alter the creep performance of the ferritic/martensitic alloys. Nevertheless, when the aluminizing temperature is lowered, brittle Al-rich intermetallic phases, such as Fe{sub 2}Al{sub 5} and FeAl{sub 3}, tend to form in the coating, which may reduce the resistance to fatigue cracking. Al-containing binary masteralloys were selected based on thermodynamic calculations to reduce the Al activity in the pack cementation process and thus to prevent the formation of brittle Al-rich intermetallic phases. Thermodynamic computations were carried out using commercial software HSC 5.0 for a series of packs containing various Cr-Al binary masteralloys. The calculation results indicate that the equilibrium partial pressures of Al halides at 700 C were a function of Al

  4. Characterization of single-tube model-boiler dented intersection specimens. Final report. [PWR

    SciTech Connect

    Varsanik, R.G.; Gibbon, D.L.

    1983-05-01

    Crevice denting, caused by the uncontrolled growth of magnetite in the space between carbon-steel tube-support plates and Inconel heat-exchange tubes is a major cause of concern in nuclear steam generators. This particular form of localized corrosion has been modeled experimentally by the Westinghouse Electric Corporation using prototypical boiler systems. In this study, three corrosion specimens from these model-boiler systems have been characterized by Calgon Corporation using light and scanning electron microscopy along with both energy- and wave-length-dispersive x-ray spectrophotometry. Samples examined consisted of specimens which had been exposed to a known corrosive environment and then either left untreated, treated with calcium hydroxide, or treated with boric acid in an attempt to halt the corrosion process. The destructive examination of the samples was conducted on both polished sections as well as sections fractured in liquid nitrogen to expose uncontaminated interfaces between the multiple phases involved.

  5. Cracking and Corrosion of Composite Tubes in Black Liquor Recovery Boiler Primary Air Ports

    SciTech Connect

    Keiser, James R.; Singbeil, Douglas L.; Sarma, Gorti B.; Kish, Joseph R.; Yuan, Jerry; Frederick, Laurie A.; Choudhury, Kimberly A.; Gorog, J. Peter; Jetté, Francois R.; Hubbard, Camden R.; Swindeman, Robert W.; Singh, Prett M.; Maziasz, Phillip J.

    2006-10-01

    Black liquor recovery boilers are an essential part of kraft mills. Their design and operating procedures have changed over time with the goal of providing improved boiler performance. These performance improvements are frequently associated with an increase in heat flux and/or operating temperature with a subsequent increase in the demand on structural materials associated with operation at higher temperatures and/or in more corrosive environments. Improvements in structural materials have therefore been required. In most cases the alternate materials have provided acceptable solutions. However, in some cases the alternate materials have solved the original problem but introduced new issues. This report addresses the performance of materials in the tubes forming primary air port openings and, particularly, the problems associated with use of stainless steel clad carbon steel tubes and the solutions that have been identified.

  6. Internal boiler tube deposit weights as a basis for chemical cleaning

    SciTech Connect

    Weick, R.H.

    1994-12-31

    Owners and operators of today`s modern boilers require a foundation or support for chemical cleaning to prevent failures by excessive waterside deposits. If deposits are not removed, they will lead to overheating or corrosion related failures. Chemical cleaning at the appropriate time will avoid the risk of tube failures, while minimizing chemical cleaning and associated waste disposal costs. Internal deposit weight guidelines are presented to fulfill this requirement.

  7. Selection of stainless steel tubes to minimize hot corrosion in utility boilers

    SciTech Connect

    Fujikawa, H.; Makiura, H.

    1982-12-01

    Austenitic stainless steel tubes of AISI 304, 316, 321, and 347 types are sometimes exposed to severe hot corrosion environments in superheaters and reheaters of utility boilers. Hot corrosion depends on the existence of V/sub 2/O/sub 5/ and Na/sub 2/SO/sub 4/ in the oil-fired boilers, and of Na/sub 2/SO/sub 4/ and K/sub 2/SO/sub 4/ in the coal-fired boilers. Among various kinds of ash corrosions, the alkali sulphate-side corrosion has been mainly studied. Type 347 steel better resistance to alkali sulphate-side corrosion than 304, 316, and 321 steels. Alloying with Nb was more effective than Mo or Ti. A (Cr, Fe, Ni)-spinel oxide layer with little ash content formed at the scale-metal interface in 347 steel. In field tests, 347 tubes have maintained good resistance to both fire-side and steam-side corrosion for five years. However, 321 tubes were removed after three years of service, because of severe fire-side corrosion.

  8. Failure Investigation of Radiant Platen Superheater Tube of Thermal Power Plant Boiler

    NASA Astrophysics Data System (ADS)

    Ghosh, D.; Ray, S.; Mandal, A.; Roy, H.

    2015-04-01

    This paper highlights a case study of typical premature failure of a radiant platen superheater tube of 210 MW thermal power plant boiler. Visual examination, dimensional measurement and chemical analysis, are conducted as part of the investigations. Apart from these, metallographic analysis and fractography are also conducted to ascertain the probable cause of failure. Finally it has been concluded that the premature failure of the super heater tube can be attributed to localized creep at high temperature. The corrective actions has also been suggested to avoid this type of failure in near future.

  9. Investigations of the Failure in Boilers Economizer Tubes Used in Power Plants

    NASA Astrophysics Data System (ADS)

    Moakhar, Roozbeh Siavash; Mehdipour, Mehrad; Ghorbani, Mohammad; Mohebali, Milad; Koohbor, Behrad

    2013-09-01

    In this study, failure of a high pressure economizer tube of a boiler used in gas-Mazut combined cycle power plants was studied. Failure analysis of the tube was accomplished by taking into account visual inspection, thickness measurement, and hardness testing as well as microstructural observations using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and x-ray diffraction (XRD). Optical microscopy images indicate that there is no phase transformation during service, and ferrite-pearlite remained. The results of XRD also revealed Iron sulfate (FeSO4) and Iron hydroxide sulfate (FeOH(SO4)) phases formed on the steel surface. A considerable amount of Sulfur was also detected on the outer surface of the tube by EDS analysis. Dew-point corrosion was found to be the principal reason for the failure of the examined tube while it has been left out-of-service.

  10. Protective coatings for composite tubes in space applications

    NASA Technical Reports Server (NTRS)

    Dursch, Harry W.; Hendricks, Carl L.

    1987-01-01

    Protective coatings for graphite/epoxy (Gr/Ep) tubular structures for a Manned Space Station truss structure were evaluated. The success of the composite tube truss structure depends on its stability to long-term exposure to the Low Earth Orbit (LEO) environment with particular emphasis placed on atomic oxygen. Concepts for protectively coating Gr/Ep tubes include use of inorganic coated metal foils and electroplating. These coatings were applied to Gr/Ep tubes and then subjected to simulated LEO environmnet to evaluate survivability of coatings and coated tubes. Evaluation included: atomic oxygen resistance, changes in optical properties and adhesion, abrasion resistancem surface preparation required, coating uniformity, and formation of microcracks in the Gr/Ep tubes caused by thermal cycling. Program results demonstrated that both phosphoric and chromic acid anodized Al foil provided excellent adhesion to Gr/Ep tubes and exhibited stable optical properties when subjected to simulated LEO environment. The SiO2/Al coatings speuttered onto Al foils also resulted in an excellent protective coating. Electroplated Ni exhibited unaccepatble adhesion loss to Gr/Ep tubes during atomic oxygen exposure.

  11. Protective coatings for composite tubes in space applications

    NASA Technical Reports Server (NTRS)

    Dursch, Harry W.; Hendricks, Carl L.

    1987-01-01

    Protective coatings for graphite/epoxy (Gr/Ep) tubular structures for a manned Space Station truss structure were evaluated. The success of the composite tube truss structure depends on its stability to long-term exposure to the low earth orbit (LEO) environment, with particular emphasis placed on atomic oxygen. Concepts for protectively coating Gr/Ep tubes include use of inorganic coated metal foils and electroplating. These coatings were applied to Gr/Ep tubes and then subjected to simulated LEO environment to evaluate survivability of coatings and coated tubes. Evaluation included: atomic oxygen resistance, changes in optical properties and adhesion, abrasion resistance, surface preparation required, coating uniformity, and formation of microcracks in the Gr/Ep tubes caused by thermal cycling. Program results demonstrated that both phosphoric and chromic acid anodized Al foil provided excellent adhesion to Gr/Ep tubes and exhibited stable optical properties when subjected to simulated LEO environment. The SiO2/Al coatings sputtered onto Al foils also resulted in an excellent protective coating. Electroplated Ni exhibited unacceptable adhesion loss to Gr/Ep tubes during atomic oxygen exposure.

  12. Power plant VII - Air-air /tube boiler/

    NASA Astrophysics Data System (ADS)

    Roche, M.

    An attempt to design a solar thermal electric central receiver power plant in the multi-MW size with acceptable efficiencies using air in the power loop is described. The turbine and generator are placed in the tower to reduce heat losses in the superheated gas, and the depleted gas loop is coupled to a low temperature generator powered by boiling water. The receiver cavity is configured to retain a maximum amount of flux and has brick walls. Nickel alloys are indicated for the air tubes in the receiver, with Inconel 601, Incoloy 800, and Inconel 600 considered acceptable. The gas leaving the chamber will be at 950 C to power a high pressure turbine, followed by entrance into a heat exchanger to boil the water for the low-pressure turbine, and is then discharged. Thermodynamic efficiencies between 13.9-20.3 percent for a 4700 kW plant are considered feasible with the design.

  13. Thermal Spray Coatings for High-Temperature Corrosion Protection in Biomass Co-Fired Boilers

    NASA Astrophysics Data System (ADS)

    Oksa, M.; Metsäjoki, J.; Kärki, J.

    2015-01-01

    There are over 1000 biomass boilers and about 500 plants using waste as fuel in Europe, and the numbers are increasing. Many of them encounter serious problems with high-temperature corrosion due to detrimental elements such as chlorides, alkali metals, and heavy metals. By HVOF spraying, it is possible to produce very dense and well-adhered coatings, which can be applied for corrosion protection of heat exchanger surfaces in biomass and waste-to-energy power plant boilers. Four HVOF coatings and one arc sprayed coating were exposed to actual biomass co-fired boiler conditions in superheater area with a probe measurement installation for 5900 h at 550 and 750 °C. The coating materials were Ni-Cr, IN625, Fe-Cr-W-Nb-Mo, and Ni-Cr-Ti. CJS and DJ Hybrid spray guns were used for HVOF spraying to compare the corrosion resistance of Ni-Cr coating structures. Reference materials were ferritic steel T92 and nickel super alloy A263. The circulating fluidized bed boiler burnt a mixture of wood, peat and coal. The coatings showed excellent corrosion resistance at 550 °C compared to the ferritic steel. At higher temperature, NiCr sprayed with CJS had the best corrosion resistance. IN625 was consumed almost completely during the exposure at 750 °C.

  14. Thermal Spray Coatings for High-Temperature Corrosion Protection in Biomass Co-Fired Boilers

    NASA Astrophysics Data System (ADS)

    Oksa, M.; Metsäjoki, J.; Kärki, J.

    2014-09-01

    There are over 1000 biomass boilers and about 500 plants using waste as fuel in Europe, and the numbers are increasing. Many of them encounter serious problems with high-temperature corrosion due to detrimental elements such as chlorides, alkali metals, and heavy metals. By HVOF spraying, it is possible to produce very dense and well-adhered coatings, which can be applied for corrosion protection of heat exchanger surfaces in biomass and waste-to-energy power plant boilers. Four HVOF coatings and one arc sprayed coating were exposed to actual biomass co-fired boiler conditions in superheater area with a probe measurement installation for 5900 h at 550 and 750 °C. The coating materials were Ni-Cr, IN625, Fe-Cr-W-Nb-Mo, and Ni-Cr-Ti. CJS and DJ Hybrid spray guns were used for HVOF spraying to compare the corrosion resistance of Ni-Cr coating structures. Reference materials were ferritic steel T92 and nickel super alloy A263. The circulating fluidized bed boiler burnt a mixture of wood, peat and coal. The coatings showed excellent corrosion resistance at 550 °C compared to the ferritic steel. At higher temperature, NiCr sprayed with CJS had the best corrosion resistance. IN625 was consumed almost completely during the exposure at 750 °C.

  15. Boiler tube failures at New Boston: a root-cause analysis. Final report

    SciTech Connect

    Land, R.E.; Tome, A.E. Jr.; Adams, R.; Flaherty, P.A.; Johnson, P.

    1985-04-01

    In-depth root-cause analysis of equipment problems at power stations is an effective means of maintaining and improving availability. An earlier EPRI study, ''Utility-Oriented Approach for Root-Cause Analysis of Power Plant Equipment Problems,'' proposed a general approach to problem analysis for use by utilities. This report presents the results of a study intended both to test and refine that approach by applying it to an actual power station problem. The problem selected was a recurring tube failure problem at Boston Edison's New Boston Generating Station. Major conclusions of the study are that overheating tube failures at New Boston are the result of several major causes. Primary among these are localized temperature spikes caused by burner-firing patterns and fuel-oil control practices during startup and shutdown, internal fouling in the waterwall-tubes, and flow diversion and flow starvation caused by leaks between feed headers. All of these causes have been aggravated by physical damage done to the boiler walls in the early years of unit operation because operating practices for subcritical, once-through boilers were poorly understood. A list of eight corrective actions to reduce overheating tube failures was generated as a result of the root-cause analysis of the data. 80 figs., 5 tabs.

  16. Automating data analysis during the inspection of boiler tubes using line scanning thermography

    NASA Astrophysics Data System (ADS)

    Ley, Obdulia; Momeni, Sepand; Ostroff, Jason; Godinez, Valery

    2012-05-01

    Failures in boiler waterwalls can occur when a relatively small amount of corrosion and loss of metal have been experienced. This study presents our efforts towards the application of Line Scanning Thermography (LST) for the analysis of thinning in boiler waterwall tubing. LST utilizes a line heat source to thermally excite the surface to be inspected and an infrared detector to record the transient surface temperature increase observed due to the presence of voids, thinning or other defects. In waterwall boiler tubes the defects that can be detected using LST correspond to corrosion pitting, hydrogen damage and wall thinning produced by inadequate burner heating or problems with the water chemistry. In this paper we discuss how the LST technique is implemented to determine thickness from the surface temperature data, and we describe our efforts towards developing a semiautomatic analysis tool to speed up the time between scanning, reporting and implementing repairs. We compare the density of data produced by the common techniques used to assess wall thickness and the data produced by LST.

  17. Utilization of coal-water fuels in fire-tube boilers. Final report, October 1990--August 1994

    SciTech Connect

    Sommer, T.; Melick, T.; Morrison, D.

    1994-12-31

    The objective of this DOE sponsored project was to successfully fire coal-water slurry in a fire-tube boiler that was designed for oil/gas firing and establish a data base that will be relevant to a large number of existing installations. Firing slurry in a fire-tube configuration is a very demanding application because of the extremely high heat release rates and the correspondingly low furnace volume where combustion can be completed. Recognizing that combustion efficiency is the major obstacle when firing slurry in a fire-tube boiler, the program was focused on innovative approaches for improving carbon burnout without major modifications to the boiler. The boiler system was successfully designed and operated to fire coal-water slurry for extended periods of time with few slurry related operational problems. The host facility was a 3.8 million Btu/hr Cleaver-Brooks fire-tube boiler located on the University of Alabama Campus. A slurry atomizer was designed that provided outstanding atomization and was not susceptible to pluggage. The boiler was operated for over 1000 hours and 12 shipments of slurry were delivered. The new equipment engineered for the coal-water slurry system consisted of the following: combustion air and slurry heaters; cyclone; baghouse; fly ash reinjection system; new control system; air compressor; CWS/gas burner and gas valve train; and storage tank and slurry handling system.

  18. ANSYS Fluent Modelling of an Underexpanded Supersonic Sootblower Jet Impinging into Recovery Boiler Tube Geometries

    NASA Astrophysics Data System (ADS)

    Doroudi, Shahed

    Sootblowers generate high pressure supersonic steam jets to control fireside deposition on heat transfer tubes of a kraft recovery boiler. Sootblowing is energy expensive, using 3-12% of the mill's total steam production. This motivates research on the dynamics of sootblower jet interaction with tubes and deposits, to optimize their use. A CFD investigation was performed using ANSYS Fluent 15.0 to model three-dimensional steady-state impingement of a Mach 2.5 mildly underexpanded (PR 1.2) air jet onto arrays of cylindrical tubes with and without fins, at various nozzle-to-tube centerline offsets. A free jet and four impingement cases for each of the economizer and generating bank geometries are compared to experimental visualizations. Pressure distributions on impinging surfaces suggest that the fins in the economizer produce a reduced but uniform sootblowing force. Pressure contours along the tubes (in the vertical direction) show a sharp decline one tube diameter away from the jet mid-plane.

  19. Role of Ash Deposits in the High Temperature Corrosion of Boiler Tubes

    SciTech Connect

    Covino, B.S., Jr.; Russell, J.H.; Cramer, S.D.; Holcomb, G.R.; Bullard, S.J.; Ziomek-Moroz, M.; Matthes, S.A.; White, M.L.

    2003-03-16

    Ash deposits cause accelerated corrosion of waterwall boiler tubes in waste to energy (WTE) incinerators. To study this effect, a series of experiments were planned to determine the mechanism of corrosion of carbon steel boiler tubes under ash deposits. Results reported here were for carbon steel tubes exposed to an environment consisting of O{sub 2}, CO{sub 2}, N{sub 2}, and water vapor. Future experiments will include HCl and SO{sub 2}. Test procedures included both isothermal and thermal gradient tests. Temperatures ranged from 300 C to 510 C for the isothermal tests and a metal/gas temperature of 450/670 C for the thermal gradient test. Initial results indicated that increasing temperature caused the isothermal corrosion rates of ash-covered samples to increase. A shakedown test of a thermal gradient test apparatus was conducted at a metal/gas temperature of 450/670 C, a more severe environment than normally encountered in WTE waterwalls. Results showed that the corrosion rate under those conditions exceeds the isothermal corrosion rates at the same metal temperature by a factor of 2 or more.

  20. The compact circulating fluidized bed boiler with a finned tube impact separator and a uniflow square cyclone

    SciTech Connect

    Li Xiaodong; Chi Yong; Yan Jianhua; Jiang Xuguang; Yang Jialin; Huang Guoquan; Ni Mingjiang; Cen Kefa

    1999-07-01

    Institute for Thermal Power Engineering, Zhejiang University has introduced a circulating fluidized bed boiler with two stage compact separation. A finned tube impact separator is located at the outlet of the furnace and a uniflow square cyclone is adopted behind the superheater. The flow characteristics of the finned tube separator are measured using a three dimensional particles dynamics analyzer. The measurements show that the reflux flow existing near the front of a finned tube has a very important effect on particle separation. The shape of a uniflow square cyclone is different with a conventional uniflow cyclone and can be laid conveniently in the flue duct of the boiler. A lot of experimental studies have been done focusing on the above separators' performances. The experimental results show that separation efficiency of the uniflow square cyclone can be up to 99% for particles with mean size 0.167 mm and its pressure drop is lower than 1,000 Pa. To change the shape of the cyclone's exhaust pipe is very effective. Based on the results, the optimization design of the separators is reported. The finned tube impact separator has been successfully applied in several circulating fluidized bed boilers. Institute for Thermal Power Engineering, Zhejiang University has designed a compact circulating fluidized bed boiler with the finned tube impact separator and a uniflow square cyclone, and the boilers capacity is 65 t/h (12 MWe).

  1. Creep-Rupture Behavior and Recrystallization in HR6W and Haynes Alloy 230 Cold-Bent Boiler Tubing for Ultrasupercritical (USC) Steam Boiler Applications

    SciTech Connect

    Shingledecker, John P

    2007-01-01

    Creep-rupture experiments were conducted on HR6W and Haynes 230, candidate Ultrasupercritical (USC) alloys, tubes to evaluate the effects of cold-work and recrystallization during high-temperature service. These creep tests were performed by internally pressurizing cold-bent boiler tubes at 775 C for times up to 8000 hours. The bends were fabricated with cold-work levels beyond the current ASME Boiler and Pressure Vessel (ASME B&PV) Code Section I limits for austenitic stainless steels. Destructive metallographic evaluation of the crept tube bends was used to determine the effects of cold-work and the degree of recrystallization. The metallographic analysis combined with an evaluation of the creep and rupture data suggest that solid-solution strengthened nickel-based alloys can be fabricated for high-temperature service at USC conditions utilizing levels of cold-work higher than the current allowed levels for austenitic stainless steels.

  2. Performance of composite coatings in a coal-fired boiler environment

    SciTech Connect

    Nava, J.C.

    2009-09-15

    Four samples of thermal spray coatings, each made from different core wire consumables by twin wire arc spray, were exposed for 18 months in a coal-fired boiler environment. The tests are described and the performance of each coating is evaluated. Results indicated that the four consumable wire alloys showed remarkable resistance to fly ash erosion and corrosion over the period of the test.

  3. Nonlinear Acoustic Evaluation of Creep Damage in Boiler Heat Exchange Tubes

    NASA Astrophysics Data System (ADS)

    Ohtani, Toshihiro; Kawashima, Koichiro; Drew, Michael; Guagliard, Paul

    2007-07-01

    In this study, we evaluated creep damage accumulation in steel welds using the nonlinear acoustic method and microstructural observation. The welds used for the experiment had been employed in boiler exchange tubes of a fossil fuel power plant for 20 years. Samples were cut from the welded region so that they had two planes parallel to the longitudinal direction of the tubes. For the nonlinear acoustic method, we used the immersion technique. Burst waves of 18 MHz were transmitted to the samples, and harmonic waves were detected in the reflection to obtain the images of amplitudes. Increased amplitudes were measured around the heat-affected zone (HAZ), which corresponded to the areas of high creep void density observed by microscopy. The nonlinear acoustic method has been confirmed to have the potential to assess the creep damage.

  4. Development of Computational Capabilities to Predict the Corrosion Wastage of Boiler Tubes in Advanced Combustion Systems

    SciTech Connect

    Kung, Steven; Rapp, Robert

    2014-08-31

    coal-fired boilers resulting from the coexistence of sulfur and chlorine in the fuel. A new corrosion mechanism, i.e., “Active Sulfidation Corrosion Mechanism,” has been proposed to account for the accelerated corrosion wastage observed on the furnace walls of utility boilers burning coals containing sulfur and chlorine. In addition, a second corrosion mechanism, i.e., “Active Sulfide-to-Oxide Corrosion Mechanism,” has been identified to account for the rapid corrosion attack on superheaters and reheaters. Both of the newly discovered corrosion mechanisms involve the formation of iron chloride (FeCl2) vapor from iron sulfide (FeS) and HCl, followed by the decomposition of FeCl2 via self-sustaining cycling reactions. For higher alloys containing sufficient chromium, the attack on superheaters and reheaters is dominated by Hot Corrosion in the presence of a fused salt. Furthermore, two stages of the hot corrosion mechanism have been identified and characterized in detail. The initiation of hot corrosion attack induced by molten sulfate leads to Stage 1 “acidic” fluxing and re-precipitation of the protective scale formed initially on the deposit-covered alloy surfaces. Once the protective scale is penetrated, Stage 2 Hot Corrosion is initiated, which is dominated by “basic” fluxing and re-precipitation of the scale in the fused salt. Based on the extensive corrosion information generated from this project, corrosion modeling was performed using non-linear regression analysis. As a result of the modeling efforts, two predictive equations have been formulated, one for furnace walls and the other for superheaters and reheaters. These first-of-the-kind equations can be used to estimate the corrosion rates of boiler tubes based on coal chemistry, alloy compositions, and boiler operating conditions for advanced boiler systems.

  5. Method of coating graphite tubes with refractory metal carbides

    DOEpatents

    Wohlberg, C.

    1973-12-11

    A method of coating graphite tubes with a refractory metal carbide is described. An alkali halide is reacted with a metallic oxide, the metallic portion being selected from the IVth or Vth group of the Periodic Table, the resulting salt reacting in turn with the carbon to give the desired refractory metal carbide coating. (Official Gazette)

  6. Thermographic imaging of material loss in boiler water-wall tubing by application of scanning line source

    NASA Astrophysics Data System (ADS)

    Cramer, K. Elliott; Winfree, William P.

    2000-06-01

    Localized wall thinning due to corrosion in utility boiler water-wall tubing is a significant inspection concern for boiler operators. Historically, conventional ultrasonics has been used for inspection of these tubes. This technique has proven to be very manpower and time intensive. This has resulted in a 'spot check' approach to inspections, documenting thickness measurements over a relatively small percentage of the total boiler wall area. NASA Langley Research Center has developed a thermal NDE technique designed to image and quantitatively characterize the amount of material thinning present in steel tubing. The technique involves the movement of a thermal line source across the outer surface of the tubing followed by an infrared imager at a fixed distance behind the line source. Quantitative images of the material loss due to corrosion are reconstructed from measurements of the induced surface temperature variations. This paper will present a discussion of the development of the thermal imaging system as well as the techniques used to reconstruct images of flaws. The application of the thermal line source coupled with the analysis technique represents a significant improvement in the inspection speed for large structures such as boiler water-walls. A theoretical basis for the technique will be presented which explains the quantitative nature of the technique. Further, a dynamic calibration system will be presented for the technique that allows the extraction of thickness information from the temperature data. Additionally, the results of applying this technology to actual water-wall tubing samples and in situ inspections will be presented.

  7. Thermographic Imaging of Material Loss in Boiler Water-Wall Tubing by Application of Scanning Line Source

    NASA Technical Reports Server (NTRS)

    Cramer, K. Elliott; Winfree, William P.

    2000-01-01

    Localized wall thinning due to corrosion in utility boiler water-wall tubing is a significant inspection concern for boiler operators. Historically, conventional ultrasonics has been used for inspection of these tubes. This technique has proven to be very manpower and time intensive. This has resulted in a spot check approach to inspections, documenting thickness measurements over a relatively small percentage of the total boiler wall area. NASA Langley Research Center has developed a thermal NDE technique designed to image and quantitatively characterize the amount of material thinning present in steel tubing. The technique involves the movement of a thermal line source across the outer surface of the tubing followed by an infrared imager at a fixed distance behind the line source. Quantitative images of the material loss due to corrosion are reconstructed from measurements of the induced surface temperature variations. This paper will present a discussion of the development of the thermal imaging system as well as the techniques used to reconstruct images of flaws. The application of the thermal line source coupled with the analysis technique represents a significant improvement in the inspection speed for large structures such as boiler water-walls. A theoretical basis for the technique will be presented which explains the quantitative nature of the technique. Further, a dynamic calibration system will be presented for the technique that allows the extraction of thickness information from the temperature data. Additionally, the results of applying this technology to actual water-wall tubing samples and in situ inspections will be presented.

  8. Condenser tube erosion-corrosion repairs using coatings

    SciTech Connect

    Lichtenstein, J.

    2000-02-01

    Condenser corrosion and erosion problems involving condenser (heat exchanger) water boxes, tubesheets, and tubes have been a maintenance problem for many years and continue to be so. Most often the materials of construction for surface condensers are galvanically incompatible. Usually the water box is carbon steel (CS) or cast iron, the tubesheet can be either CS or a copper-based alloy, and the tubes frequently are either a copper-based alloy, stainless steel (SS), or titanium. When erosion-corrosion problems arise and upgrading the tube alloy is not feasible or does not correct the problem there is a relatively inexpensive method of preventing or reducing the damage--thereby prolonging the life of the tube. Operators can coat the inlet end in the attacked region (normally 6 to 10 in. inside the tube) and the tubesheet. The coating material usually is a 100% solid epoxy or other high-solids, high-quality organic material.

  9. Model boiler testing to evaluate inhibitors for caustic induced stress corrosion cracking of Alloy 600 tubes

    SciTech Connect

    Daret, J.; Paine, J.P.N.; Partridge, M.J.

    1995-12-31

    A series of model boiler tests, using a mixture of precracked and non-precracked (virgin) tube-to-tube support plate intersections was performed. The testing supported the qualification of inhibitors for mitigating the secondary side corrosion of alloy 600 steam generator tubes. Many utilities suspect that the caustic impurities come from the feedwater. Candidate inhibitors included boric acid (as a reference), cerous acetate, and two forms of titanium dioxide: a laboratory produced titania-silica sol-gel, and manometer sized anatase The latter was combined with a 150 C pre-soaking with a titanium lactate, and was tested with and without a zeta potential treatment by sodium aluminate. Effectiveness of boric acid to prevent and retard caustic induced intergranular corrosion was confirmed in all crevice configurations (open and packed). The cerous acetate treatment multiplied by two to four the time necessary to detect a primary-to-secondary leak on virgin tubes, and reduced the propagation rate on precracked tubes. Cerium was found intimately mixed, as cerianite, with the free span and crevice deposits, when the crevices were sufficiently accessible. Due to its very low solubility and large particle size, the titania-silica sol-gel was unable to penetrate the crevices and had no effect on the degradation process. The nanometric particle size titania treatment and/or the preceding soaking with soluble titanium lactate drastically increased the titanium concentration in free span and open crevice deposit (with no added sodium aluminate, titania reacted with magnetite to form ilmenite) and showed undeniable capacity to prevent tubing degradation. Its effectiveness, in the case of packed crevices and for arresting cracks, was not so conclusive.

  10. Increased Lifetime for Biomass and Waste to Energy Power Plant Boilers with HVOF Coatings: High Temperature Corrosion Testing Under Chlorine-Containing Molten Salt

    NASA Astrophysics Data System (ADS)

    Oksa, Maria; Tuurna, Satu; Varis, Tommi

    2013-06-01

    Heat exchanger surfaces of waste to energy and biomass power plant boilers experience often severe corrosion due to very aggressive components in the used fuels. High velocity oxy-fuel (HVOF) coatings offer excellent protection for boiler tubes against high temperature corrosion due to their high density and good adherence to the substrate material. Several thermal spray coatings with high chromium content were sprayed with HVOF technique. Their mechanical properties and high temperature corrosion resistance were tested and analyzed. The coating materials included NiCr, IN625, Ni-21Cr-10W-9Mo-4Cu, and iron-based partly amorphous alloy SHS9172 (Fe-25Cr-15W-12Nb-6Mo). High temperature corrosion testing was performed in NaCl-KCl-Na2SO4 salt with controlled H2O atmosphere at 575 and 625 °C. The corrosion test results of the coatings were compared to corrosion resistance of tube materials (X20, Alloy 263 and Sanicro 25).

  11. Cryogenic testing of fluoropolymer-coated stainless steel tubing

    SciTech Connect

    Dooley, J.B.

    1989-11-01

    Stainless steel tubing coated internally with two different types of fluorinated polymers were subjected to microscopic examination after a welding operation had been performed on the tubing. The welded assemblies were photographed and subjected to repeated cycles between liquid helium and room temperature. The green tetrafluoroethylene (TFE) coating peeled back in the area subjected to welding heat and displayed cracking all over its surface without regard to proximity to the weld area. The dark fluorinated ethylene propylene (FEP) coating showed a tendency to char or burn away progressively in the weld area. The dark (FEP) coating did not crack as extensively as the green TFE coating, but did show a few areas of crazing'' or cracking of the topmost surface after cryogenic exposure. 12 figs.

  12. Experimental determination of the residual stresses in a Kraft recovery boiler tube

    SciTech Connect

    Wang, Xun-Li; Payzant, E.A.; Taljat, B.

    1997-07-01

    Neutron diffraction was used to determine the residual stresses in a spiral weld overlay tube used in Kraft recovery boilers by the pulp and paper industry. The specimen was a 2.5 inches OD carbon steel tube covered with a layer of Inconel 625 weld overlay. Residual strains in the carbon steel and weld overlay layers were determined using the ferritic (211) and austenitic (311) reflections, respectively. Residual stresses in each material were derived from the measured strains using Hooke`s law and appropriate elastic constants. Tensile stress regions were found not only in the weld metal but also in the heat affected zone in the carbon steel. The maximum tensile stress was located in the weld overlay layer and was found to be 360 MPa, or about 75% of the yield strength of the weld metal. The experimental data were compared with a finite element analysis based on an uncoupled thermal-mechanical formulation. Overall, the modeling results were in satisfactory agreement with the experimental data, although the hoop strain (stress) appears to have been overestimated by the finite element model. Additional neutron diffraction measurements on an annealed tube confirmed that these welding residual stresses were eliminated after annealing at 900{degrees}C for 20 minutes. 18 refs., 7 figs.

  13. Status Report on Studies of Recovery Boiler Composite Floor Tube Cracking

    SciTech Connect

    Eng, P.; Frederick, L.A.; Hoffmann, C.M.; Keiser, J.R.; Mahmood, J.; Maziasz, P.J.; Prescott, R.; Sarma, G.B.; Singbeil, D.L.; Singh, P.M.; Swindeman, R.W.; Wang, X.-L.

    1999-09-12

    Cracking of the stainless steel layer of co-extruded 304L stainless steel/SA210 Gd A 1 carbon steel black liquor recovery boiler floor tubes has been identified as one of the most serious material problems in the pulp and paper industry. A DOE-funded study was initiated in 1995 with the goal of determining the cause of and possible solutions to this cracking problem. These studies have characterized tube cracking as well as the chemical and thermal environment and stress state of floor tubes. Investigations of possible cracking mechanisms indicate that stress corrosion cracking rather than thermal fatigue is a more likely cause of crack initiation. The cracking mechanism appears to require the presence of hydrated sodium sulfide and is most likely active during shut-downs and/or start-ups. Based on these results and operating experience, certain alloys appear to be more resistant than others to cracking in the floor environment, and certain operating practices appear to significantly lessen the likelihood of cracking. This report is the latest in a series of progress reports presented on this project.

  14. Corrosion/erosion detection of boiler tubes utilizing pulsed infrared imaging

    NASA Astrophysics Data System (ADS)

    Bales, Maurice J.; Bishop, Chip C.

    1995-05-01

    This paper discusses a new technique for locating and detecting wall thickness reduction in boiler tubes caused by erosion/corrosion. Traditional means for this type of defect detection utilizes ultrasonics (UT) to perform a point by point measurement at given intervals of the tube length, which requires extensive and costly shutdown or `outage' time to complete the inspection, and has led to thin areas going undetected simply because they were located in between the sampling points. Pulsed infrared imaging (PII) can provide nearly 100% inspection of the tubes in a fraction of the time needed for UT. The IR system and heat source used in this study do not require any special access or fixed scaffolding, and can be remotely operated from a distance of up to 100 feet. This technique has been tried experimentally in a laboratory environment and verified in an actual field application. Since PII is a non-contact technique, considerable time and cost savings should be realized as well as the ability to predict failures rather than repairing them once they have occurred.

  15. Experimental investigation on heat transfer and frictional characteristics of vertical upward rifled tube in supercritical CFB boiler

    SciTech Connect

    Yang, Dong; Pan, Jie; Zhu, Xiaojing; Bi, Qincheng; Chen, Tingkuan; Zhou, Chenn Q.

    2011-02-15

    Water wall design is a key issue for supercritical Circulating Fluidized Bed (CFB) boiler. On account of the good heat transfer performance, rifled tube is applied in the water wall design of a 600 MW supercritical CFB boiler in China. In order to investigate the heat transfer and frictional characteristics of the rifled tube with vertical upward flow, an in-depth experiment was conducted in the range of pressure from 12 to 30 MPa, mass flux from 230 to 1200 kg/(m{sup 2} s), and inner wall heat flux from 130 to 720 kW/m{sup 2}. The wall temperature distribution and pressure drop in the rifled tube were obtained in the experiment. The normal, enhanced and deteriorated heat transfer characteristics were also captured. In this paper, the effects of pressure, inner wall heat flux and mass flux on heat transfer characteristics are analyzed, the heat transfer mechanism and the frictional resistance performance are discussed, and the corresponding empirical correlations are presented. The experimental results show that the rifled tube can effectively prevent the occurrence of departure from nucleate boiling (DNB) and keep the tube wall temperature in a permissible range under the operating condition of supercritical CFB boiler. (author)

  16. Etching of Copper Coated Mylar Tubes With CF-4 Gas

    DOE PAGESBeta

    Ecklund, Karl M.; Hartman, Keith W.; Hebert, Michael J.; Wojcicki, Stanley G.

    1996-04-01

    Using 5 mm diameter copper coated mylar straw tubes at a potential of 2.30 KV relative to a concentric 20 (mu)m diameter gold-plated tungsten anode, it has been observed that with very low flow rates of CF4-based gases the conductive copper cathode material may be removed entirely from the mylar surface.

  17. Cermet composite thermal spray coatings for erosion and corrosion protection in combustion environments of advanced coal-fired boilers. Semi-annual technical progress report, February 1996--July 1996

    SciTech Connect

    Banovic, S.W.; Levin, B.F.; DuPont, J.N.; Marder, A.R.

    1996-08-01

    Present coal-fired boiler environments remain hostile to the materials of choice since corrosion and erosion can be a serious problem in certain regions of the boiler. Recently, the Clean Air Act Amendment is requiring electric power plants to reduce NO{sub x}, emissions to the environment. To reduce NO{sub x}, emissions, new low NO{sub x}, combustors are utilized which burn fuel with a substoichiometric amount of oxygen (i.e., low oxygen partial pressure). In these low NO{sub x} environments, H{sub 2}S gas is a major source of sulfur. Due to the sulfidation process, corrosion rates in reducing parts of boilers have increased significantly and existing boiler tube materials do not always provide adequate corrosion resistance. Combined attack due to corrosion and erosion is a concern because of the significantly increased operating costs which result in material failures. One method to combat corrosion and erosion in coal-fired boilers is to apply coatings to the components subjected to aggressive environments. Thermal spray coatings, a cermet composite comprised of hard ceramic phases of oxide and/or carbide in a metal binder, have been used with some success as a solution to the corrosion and erosion problems in boilers. However, little is known on the effect of the volume fraction, size, and shape of the hard ceramic phase on the erosion and corrosion resistance of the thermally sprayed coatings. It is the objective of this research to investigate metal matrix composite (cermet) coatings in order to determine the optimum ceramic/metal combination that will give the best erosion and corrosion resistance in new advanced coal-fired boilers.

  18. Causes and solutions for cracking of coextruded and weld overlay floor tubes in black liquor recovery boilers

    SciTech Connect

    Keiser, J.R.; Taljat, B.; Wang, X.L.

    1998-09-01

    Cracking of coextruded, black liquor recovery boiler floor tubes is both a safety and an economic issue to mill operators. In an effort to determine the cause of the cracking and to identify a solution, extensive studies, described in this and three accompanying papers, are being conducted. In this paper, results of studies to characterize both the cracking and the chemical and thermal environment are reported. Based on the results described in this series of papers, a possible mechanism is presented and means to lessen the likelihood of cracking or to totally avoid cracking of floor tubes are offered.

  19. Single Wall Carbon Nano Tube Films and Coatings

    NASA Astrophysics Data System (ADS)

    Sreekumar, T. V.; Kumar, Satish; Ericson, Lars M.; Smalley, Richard E.

    2002-03-01

    Purified single wall carbon nano tubes (SWNTs) produced from the high-pressure carbon monoxide (HiPCO) process have been dissolved /dispersed in oleum. These solutions /dispersions were optically homogeneous and have been used to form stand-alone SWNT films. The washed, dried, and heat-treated films are isotropic. The scanning electron micrographs of the film surface shows that the nanotube ropes (or fibrils) of about 20 nm diameters are arranged just like macroscopic fibers in a non-woven fabric. Polarized Raman spectroscopy of the SWNT film confirms the isotropic nature of these films. The films are being characterized for their thermal, mechanical as well electrical properties. Thin nano tube coatings, including optically transparent coatings, have also been made on a variety of substrates such as glass, polyethylene, polystyrene, polypropylene, silicon wafer, as well as stainless steel.

  20. INFLUENCE OF OXIDE GROWTH AND METAL CREEP ON STRAIN DEVELOPMENT IN THE STEAM-SIDE OXIDE IN BOILER TUBES

    SciTech Connect

    Sabau, Adrian S; Wright, Ian G

    2010-01-01

    This effort is concerned with developing a quantitative description of the exfoliation behavior of oxide scales grown inside steam tubes in a pressure boiler. Consideration of the development of stress/strain in growing oxides has included expansion mismatch-induced strains during thermal cycling as well as inelastic mechanical effects from oxide/alloy creep phenomena and volume change from oxide growth. The magnitude of the parameters used has been closely matched to actual boiler operating practice. The creep model used was validated against published data. Representation of oxide growth-induced strain was found to be a difficult challenge because the processes involved are not fully understood. In addition to the traditional uniaxial (radial) and dilatational models, lateral growth models are discussed in the context of experimentally-derived criteria, such as the level of elastic strains involved in oxide exfoliation. It was found that strain variation in the oxide cannot be neglected.

  1. Degradation behavior of Ni3Al plasma-sprayed boiler tube steels in an energy generation system

    NASA Astrophysics Data System (ADS)

    Sidhu, Buta Singh; Prakash, S.

    2005-06-01

    Boiler steels, namely, low-C steel, ASTM-SA210-Grade A1 (GrA1), 1Cr-0.5Mo steel, ASTM-SA213-T-11 (T11) and 2.25Cr-1Mo steel, ASTM-SA213-T-22 (T22) were plasma sprayed with Ni3Al. The alloy powder was prepared by mixing Ni and Al in the stoichiometric ratio of 3 to 1. The Ni-22Cr-10Al-1Y alloy powder was used as a bond coat, with a 150 µm thick layer sprayed onto the surface before applying the 200 µm coating of Ni3Al. Exposure studies have been performed in the platen superheater zone of a coal-fired boiler at around 755 °C for 10 cycles, each of 100 h duration. The protection to the base steel was minimal for the three steels. Scale spallation and the formation of a porous and nonadherent NiO scale were probably the main reasons for the lack of protection. In the case of T22-coated steel, cracks in the coatings have been observed after the first 100 h exposure cycle.

  2. Evaluation of silica-coated tubing for the measurement of hydrogen peroxide in hot water.

    SciTech Connect

    Marin, T. W.; Bartels, D. M.; Jonah, C. D.; Chemistry

    2004-04-14

    A commercial silica coating for stainless steel tubing was investigated for its ability to inhibit the decomposition of aqueous hydrogen peroxide on the tubing surface. Although the coating proves effective at preventing decomposition up to 200 {sup o}C, above this temperature, the coating degrades, as evidenced by enhanced decomposition of the hydrogen peroxide.

  3. Development of 18Cr-9Ni-W-Nb-V-N Austenitic Stainless Steel Tube for Thermal Power Boilers

    NASA Astrophysics Data System (ADS)

    Ishitsuka, Tetsuo; Mimura, Hiroyuki

    An 18Cr-9Ni-W-Nb-V-N austenitic stainless steel tube for thermal power boilers has been newly developed. The high temperature mechanical properties and corrosion resistance of the steel were investigated. The creep rupture strength of the developed steel is about 1.5 times as high as that of SUS347HTB, and is almost the same as that of Ka-SUS310J2TB at 650°C. This excellent creep strength of the steel is mainly due to solid solution strengthening by tungsten and nitrogen, and precipitation strengthening by nitrides of niobium and vanadium. The carbon content of the steel is reduced to 0.03% to improve intergranular corrosion resistance. The steam oxidation resistance and the high temperature corrosion resistance of the tube are almost the same as those of SUS347HTB. Weldability of the developed steel is superior to that of SUS304HTB and SUS310TB. Thus the developed steel is suitable for use as a material for superheater and reheater tubes of thermal power boilers.

  4. Determining the parameters at which burnout occurs in the waterwall tubes of drum boilers

    NASA Astrophysics Data System (ADS)

    Belyakov, I. I.

    2007-09-01

    Parameters at which burnout occurs are presented that were obtained by measuring the temperature and heat fluxes during experiments carried out directly on a boiler. The results of a comparison between the obtained values and the data of investigations on a test facility are given.

  5. Ionic liquid coated copper wires and tubes for fiber-in-tube solid-phase microextraction.

    PubMed

    Sun, Min; Feng, Juanjuan; Bu, Yanan; Luo, Chuannan

    2016-08-01

    A fiber-in-tube solid-phase microextraction (SPME) device was developed by filling eleven copper wires into a copper tube, and all of those were functionalized with ionic liquids. Its morphology and surface properties were characterized by scanning electron microscopy. It was connected into high performance liquid chromatography (HPLC) equipment by replacing the sample loop of six-port injection valve, building the online SPME-HPLC system. In the optimization of extraction conditions, sampling rate, sample volume, pH of sample and desorption time were investigated with five estrogens as model analytes. Under the optimum conditions, an online SPME-HPLC analysis method was achieved, showing enrichment efficiency from 611 to 1661 and a good linearity of 0.06-60μgL(-1) with low detection limits of 0.02-0.05μgL(-1). It was applied to detect estrogens analytes in two water samples, with recoveries in the range of 85-114%. Relative standard deviation (n=3) of extraction repeatability is in the range of 1.9-3.0%. Relative standard deviation of extraction tubes (n=3) is in the range of 12-19%. The extraction mechanism is probably related to hydrophobic, π-π and dipole-dipole interactions between ionic liquids coating and estrogens analytes. PMID:27381811

  6. Effect of thermal sprayed coatings on in-bed tube erosion and corrosion in the fluidized bed combustors (FBCs)

    SciTech Connect

    Lee, S.W.; Wang, B.Q.

    1996-08-01

    The selection of boiler tube materials in the elevated temperature areas of energy producing systems such as fluidized bed combustors (FBCs) is based on the material wastage rates in combined erosion-corrosion environments. Laboratory erosion-corrosion experiments at low elevated temperature (300 C) and low impact velocity (2.5 m/s) were carried out on AISI 1018 carbon steel and sprayed coating specimens. Angular silica quartz particles of 742 {micro}m were the erodent material for testing three different impact angles of 30{degree}, 45{degree}, and 90{degree} under generally oxidizing conditions for exposure periods up to 96 hours. Material wastage rates were determined from thickness loss measurements of specimens. The morphologies of the specimens were examined by scanning electron microscopy (SEM). The testing showed that some differences existed in the material wastage mechanisms and behavior of steel coatings when low impact velocity was applied. For angular dependence of erosion rate, all coatings exhibited ductile behavior as demonstrated by higher wastage rates at shallow impact angles than that at steep impact angles. The erosion-corrosion resistance of coatings was found to be related to their composition and microstructure rather than to their hardness.

  7. Superior Corrosion Resistance Properties of TiN-Based Coatings on Zircaloy Tubes in Supercritical Water

    SciTech Connect

    Fauzia Khatkhatay; Liang Jiao; Jie Jian; Zhijie Jiao; Hongbin Zhang; Jian Gan; Haiyan Wang; Wenrui Zhang; Xinghang Zhang

    2014-08-01

    Thin films of TiN and Ti0.35Al0.65N nanocomposite were deposited on polished Zircaloy-4 tubes. After exposure to supercritical water for 48 h, the coated tubes are remarkably intact, while the bare uncoated tube shows severe oxidation and breakaway corrosion. X-ray diffraction patterns, secondary electron images, backscattered electron images, and energy dispersive X-ray spectroscopy data from the tube surfaces and cross-sections show that a protective oxide, formed on the film surface, effectively prevents further oxidation and corrosion to the Zircaloy-4 tubes. This result demonstrates the effectiveness of thin film ceramics as protective coatings under extreme environments.

  8. PLASMA SPRAYED Ni-Al COATINGS FOR SAFE ENDING HEAT EXCHANGER TUBES

    SciTech Connect

    ALLAN,M.L.; OTTERSON,D.; BERNDT,C.C.

    1998-11-01

    Brookhaven National Laboratory (BNL) has developed thermally conductive composite liners for corrosion and scale protection in heat exchanger tubes exposed to geothermal brine. The liners cannot withstand roller expansion to connect the tubes to the tubesheet. It is not possible to line the ends of the tubes with the same material after roller expansion due to the nature of the current liner application process. It was requested that BNL evaluate plasma sprayed Ni-Al coatings for safe ending heat exchanger tubes exposed to geothermal brine. The tubes of interest had an internal diameter of 0.875 inches. It is not typical to thermal spray small diameter components or use such small standoff distances. In this project a nozzle extension was developed by Zatorski Coating Company to spray the tube ends as well as flat coupons for testing. Four different Ni-Al coatings were investigated. One of these was a ductilized Ni-AIB material developed at Oak Ridge National Laboratory. The coatings were examined by optical and scanning electron microscopy. In addition, the coatings were analyzed by X-ray diffraction and subjected to corrosion, tensile adhesion, microhardness and field tests in a volcanic pool in New Zealand. It was determined that the Ni-Al coatings could be applied to a depth of two inches on the tube ends. When sprayed on flat coupons the coatings exhibited relatively high adhesion strength and microhardness. Polarization curves showed that the coating performance was variable. Measured corrosion potentials indicated that the Ni-Al coatings are active towards steel coated with thermally conductive polymers, thereby suggesting preferential corrosion. Corrosion also occurred on the coated coupons tested in the volcanic pool. This may have been exacerbated by the difficulty in applying a uniform coating to the coupon edges. The Ni-Al coatings applied to the tubes had significant porosity and did not provide adequate corrosion protection. This is associated with

  9. Development of coated tubes RIA for serum T3 (tri-iodothyronine) for production scale.

    PubMed

    Karir, T; Samuel, G; Sivaprasad, N; Meera, V; Samuel, G; Meera, V; Pillai, M R A

    2005-01-01

    A coating procedure that could provide immobilization of antibodies, with increased binding capacity, that is cost effective, simple, robust, and appropriate for production scale application, is described. This coating approach of T3 antibodies to the polystyrene tubes has been systematically investigated to determine its utility for the development of coated tube Radioimmunoassay (RIA) for T3 in human serum. Further, the results obtained by the developed coating procedure are found to be comparable with those obtained by the "gold standard," the liquid phase RIA for T3. The coating procedure is completed in three major steps, each step involving an overnight incubation. The normal rabbit gamma-globulins are physically adsorbed onto the polystyrene tubes and incubated. After washing, a second antibody (goat anti-rabbit antiserum) is added and incubated. To this antigen specific antibody is added (T3 antibody produced in rabbit) and further incubated. Finally, the non-specific sites on the tubes are saturated by the blocking solution. The concentration of normal rabbit globulin, titers of second antibody and T3 antibody, and time required for coating are optimized to arrive at a suitable coating protocol. The coated tubes were evaluated for precision, reproducibility, and stability. Various parameters such as total reaction volume, incubation time and temperature, total number and volume of washings, concentration of 8-anilino-1-naphthalene sulfonic acid (ANS), and quantity of tracer per tube are optimized to arrive at a suitable standard curve. The optimized assay is validated for the quality control parameters such as intra- and inter-assay variations, recovery, and parallelism. The developed coated tubes assay had an assay range of 0.3-4.8 ng/mL with a sensitivity of 0.3 ng/mL at 90% B/B0. Batch to batch variation in coating was < 10%. The coated tubes were stable up to 1 year, which is adequate for production scale. PMID:15754806

  10. ROBUST, SPECTRALLY SELECTIVE CERAMIC COATINGS FOR RECYCLED SOLAR POWER TUBES

    EPA Science Inventory

    Seven coating systems, listed in Table 1, were evaluated. Pemco U-3101 and Neo 126 are commercial enamel coatings commonly referred to as ground and cover coats, respectively. Ferro PL214 is a commercially available black enamel coating. Ferro XG-210 is a clear enamel coat...

  11. Fireside corrosion testing of candidate superheater tube alloys, coatings, and claddings - phase II

    SciTech Connect

    Blough, J.L.; Stanko, G.J.

    1996-08-01

    In Phase I a variety of developmental and commercial tubing alloys and claddings were exposed to laboratory fireside corrosion testing simulating a superheater or reheater in a coal-fired boiler. Phase II (in situ testing) has exposed samples of 347, RA-8511, HR3C, 253MA, Fe{sub 3}Al + 5Cr, 310 modified, 800HT, NF 709, 690 clad, and 671 clad for over 10,000 hours to the actual operating conditions of a 250-MW coal-fired boiler. The samples were installed on an air-cooled, retractable corrosion probe, installed in the reheater cavity, and controlled to the operating metal temperatures of an existing and advanced-cycle coal-fired boiler. Samples of each alloy will be exposed for 4000, 12,000, and 16,000 hours of operation. The results will be presented for the metallurgical examination of the corrosion probe samples after 4000 hours of exposure.

  12. Fireside corrosion testing of candidate superheater tube alloys, coatings, and claddings -- Phase 2 field testing

    SciTech Connect

    Blough, J.L.

    1996-08-01

    In Phase 1 of this project, a variety of developmental and commercial tubing alloys and claddings was exposed to laboratory fireside corrosion testing simulating a superheater or reheater in a coal-fired boiler. Phase 2 (in situ testing) has exposed samples of 347, RA85H, HR3C, 253MA, Fe{sub 3}Al + 5Cr, 310 modified, NF 709, 690 clad, and 671 clad for over 10,000 hours to the actual operating conditions of a 250-MW coal-fired boiler. The samples were installed on air-cooled, retractable corrosion probes, installed in the reheater cavity, controlled to the operating metal temperatures of an existing and advanced-cycle, coal-fired boiler. Samples of each alloy are being exposed for 4,000, 12,000, and 16,000 hours of operation. The present results are for the metallurgical examination of the corrosion probe samples after approximately 4,400 hours of exposure.

  13. Fireside corrosion testing of candidate superheater tube alloys, coatings, and claddings -- Phase 2

    SciTech Connect

    Blough, J.L.; Stanko, G.J.

    1997-08-01

    In Phase 1 a variety of developmental and commercial tubing alloys and claddings were exposed to laboratory fireside corrosion testing simulating a superheater or reheater in a coal-fired boiler. Phase 2 (in situ testing) has exposed samples of 347, RA-85H, HR3C, 253MA, Fe{sub 3}Al + 5Cr, 310 modified, 800HT, NF 709, 690 clad, and 671 clad for over 10,000 hours to the actual operating conditions of a 250-MW coal-fired boiler. The samples were installed on an air-cooled, retractable corrosion probe, installed in the reheater cavity, and controlled to the operating metal temperatures of an existing and advanced-cycle, coal-fired boiler. Samples of each alloy will be exposed for 4,000, 12,000, and 16,000 hours of operation. The results will be presented for the metallurgical examination of the corrosion probe samples after 4,000 hours of exposure.

  14. Coating The Inner Walls Of Tubes With TiN Films By Reactive Sputtering

    SciTech Connect

    Kraus, T.; Lindner, J.K.N.; Stritzker, B.; Keckes, J.; Ensinger, W.

    2003-08-26

    It is possible to achieve a homogenous coating of the inner walls of tubes by sputter deposition. For this purpose a conical sputter target is moved through the tube parallel to its axis while an ion beam enters the tube along its axis, impinges onto the target and sputters material onto the tube inner wall. But so far only monatomic coatings were performed with this technique. To improve the mechanical properties of tubes TiN films were deposited by reactive sputtering. Therefore a Ti sputter target is used, the N2 reactive gas is delivered into the tube by a nozzle. The topography of the films is dominated by a ripple structure with the wave vector perpendicular to the tubes length axis. The development of the ripples is discussed in terms of scattered Ar projectiles which impinge onto the substrate as well as the deposited film under grazing incidence angles. Results of RBS, ERD, AFM, and hardness measurements are shown.

  15. Pool boiling of nanofluids on rough and porous coated tubes: experimental and correlation

    NASA Astrophysics Data System (ADS)

    Cieśliński, Janusz T.; Kaczmarczyk, Tomasz Z.

    2014-06-01

    The paper deals with pool boiling of water-Al2O3 and water- Cu nanofluids on rough and porous coated horizontal tubes. Commercially available stainless steel tubes having 10 mm outside diameter and 0.6 mm wall thickness were used to fabricate the test heater. The tube surface was roughed with emery paper 360 or polished with abrasive compound. Aluminium porous coatings of 0.15 mm thick with porosity of about 40% were produced by plasma spraying. The experiments were conducted under different absolute operating pressures, i.e., 200, 100, and 10 kPa. Nanoparticles were tested at the concentration of 0.01, 0.1, and 1% by weight. Ultrasonic vibration was used in order to stabilize the dispersion of the nanoparticles. It was observed that independent of operating pressure and roughness of the stainless steel tubes addition of even small amount of nanoparticles augments heat transfer in comparison to boiling of distilled water. Contrary to rough tubes boiling heat transfer coefficient of tested nanofluids on porous coated tubes was lower compared to that for distilled water while boiling on porous coated tubes. A correlation equation for prediction of the average heat transfer coefficient during boiling of nanofluids on smooth, rough and porous coated tubes is proposed. The correlation includes all tested variables in dimensionless form and is valid for low heat flux, i.e., below 100 kW/m2.

  16. Substantiation of causes for damage of water-wall tubes of an external salt compartment of a high-pressure boiler

    NASA Astrophysics Data System (ADS)

    Fedorov, A. I.

    2014-10-01

    The damageability for water-wall tubes of an external salt compartment of a TPE-208 boiler is analyzed. The general cause for tube damage is the intensive underslime corrosion of the inner surface, which is caused by a local increase in the salt concentration in boiler water. The experiment-calculated method showed that continuous bleeding from an external cyclone being the first in water downstream causes a substantial increase in the concentration of salts (more than by a factor of three) and scale-forming agents within a contour of the loop of a distant cyclone in comparison with the variant of bleeding from a loop being the second in water downstream.

  17. Combustion monitoring of a water tube boiler using a discriminant radial basis network.

    PubMed

    Sujatha, K; Pappa, N

    2011-01-01

    This research work includes a combination of Fisher's linear discriminant (FLD) analysis and a radial basis network (RBN) for monitoring the combustion conditions for a coal fired boiler so as to allow control of the air/fuel ratio. For this, two-dimensional flame images are required, which were captured with a CCD camera; the features of the images-average intensity, area, brightness and orientation etc of the flame-are extracted after preprocessing the images. The FLD is applied to reduce the n-dimensional feature size to a two-dimensional feature size for faster learning of the RBN. Also, three classes of images corresponding to different burning conditions of the flames have been extracted from continuous video processing. In this, the corresponding temperatures, and the carbon monoxide (CO) emissions and those of other flue gases have been obtained through measurement. Further, the training and testing of Fisher's linear discriminant radial basis network (FLDRBN), with the data collected, have been carried out and the performance of the algorithms is presented. PMID:20864104

  18. Corrosion loss measurement of boiler tubes in a waste incineration environment by A.C. impedance method

    SciTech Connect

    Matsunaga, Yasuo; Nakagawa, Kiyokazu

    1997-08-01

    To monitor the corrosion rate of materials of boiler tubes in simulated waste incineration environment, A.C. impedance measurements were carried out for Alloy 625, SUS347H and STBA24 embedded in NaCl- KCl- NaSO{sub 4}-K{sub 2}SO{sub 4}-Al{sub 2}O{sub 3} mixed synthetic ash deposit at 600 C. Though the ash includes some non-melting component, A.C. impedance measurements can be applied to evaluate corrosion rates in the same manner the corrosion of materials immersed in molten salts. Supposing the difference of impedance between the low frequency and high frequency ({Delta}R) as polarization resistance, a linear relation was obtained between 1/{Delta}R and corrosion losses in air, air-0.1 vol.% HCl and air-10vol.% H{sub 2}O atmospheres. The HCl addition in accelerated the corrosion of all specimens by reducing basicity of the molten salt. On the other hand, the H{sub 2}O addition reduced the corrosion of Alloy 625, but it accelerated the corrosion of SUS347H and STBA24.

  19. Plasma Sprayed Ni-Al Coatings for Safe Ending Heat Exchanger Tubes

    SciTech Connect

    Allen, M.L.; Berndt, C.C.; Otterson, D.

    1998-11-01

    Brookhaven National Laboratory (BNL) has developed thermally conductive composite liners for corrosion and scale protection in heat exchanger tubes exposed to geothermal brine. The liners cannot withstand roller expansion to connect the tubes to the tubesheet. It is not possible to line the ends of the tubes with the same material after roller expansion due to the nature of the current liner application process. It was requested that BNL evaluate plasma sprayed Ni-Al coatings for safe ending heat exchanger tubes exposed to geothermal brine. The tubes of interest had an internal diameter of 0.875 inches. It is not typical to thermal spray small diameter components or use such small standoff distances. In this project a nozzle extension was developed by Zatorski Coating Company to spray the tube ends as well as flat coupons for testing. Four different Ni-Al coatings were investigated. One of these was a ductilized Ni-AlB material developed at Oak Ridge National Laboratory. The coatings were examined by optical and scanning electron microscopy. In addition, the coatings were analyzed by X-ray diffraction and subjected to corrosion, tensile adhesion, microhardness and field tests in a volcanic pool in New Zealand.

  20. Fireside corrosion testing of candidate superheater tube alloys, coatings, and claddings -- Phase 2

    SciTech Connect

    Blough, J.L.; Seitz, W.W.

    1997-12-01

    In Phase 1 a variety of developmental and commercial tubing alloys and claddings were exposed to laboratory fireside corrosion testing simulating a superheater or reheater in a coal-fired boiler. Phase 2 (in situ testing) has exposed samples of 347 RA-85H, HR3C, 253MA, Fe{sub 3}Al + 5Cr, 310 Ta modified, NF 709, 690 clad, and 671 clad for approximately 4,000, 12,000, and 16,000 hours to the actual operating conditions of a 250-MW coal-fired boiler. The samples were assembled on an air-cooled, retractable corrosion probe, the probe was installed in the reheater activity of the boiler and controlled to the operating metal temperatures of an existing and advanced-cycle coal-fired boiler. The results will be presented for the preliminary metallurgical examination of the corrosion probe samples after 16,000 hours of exposure. Continued metallurgical and interpretive analysis is still on going.

  1. Linear regression analysis of emissions factors when firing fossil fuels and biofuels in a commercial water-tube boiler

    SciTech Connect

    Sharon Falcone Miller; Bruce G. Miller

    2007-12-15

    This paper compares the emissions factors for a suite of liquid biofuels (three animal fats, waste restaurant grease, pressed soybean oil, and a biodiesel produced from soybean oil) and four fossil fuels (i.e., natural gas, No. 2 fuel oil, No. 6 fuel oil, and pulverized coal) in Penn State's commercial water-tube boiler to assess their viability as fuels for green heat applications. The data were broken into two subsets, i.e., fossil fuels and biofuels. The regression model for the liquid biofuels (as a subset) did not perform well for all of the gases. In addition, the coefficient in the models showed the EPA method underestimating CO and NOx emissions. No relation could be studied for SO{sub 2} for the liquid biofuels as they contain no sulfur; however, the model showed a good relationship between the two methods for SO{sub 2} in the fossil fuels. AP-42 emissions factors for the fossil fuels were also compared to the mass balance emissions factors and EPA CFR Title 40 emissions factors. Overall, the AP-42 emissions factors for the fossil fuels did not compare well with the mass balance emissions factors or the EPA CFR Title 40 emissions factors. Regression analysis of the AP-42, EPA, and mass balance emissions factors for the fossil fuels showed a significant relationship only for CO{sub 2} and SO{sub 2}. However, the regression models underestimate the SO{sub 2} emissions by 33%. These tests illustrate the importance in performing material balances around boilers to obtain the most accurate emissions levels, especially when dealing with biofuels. The EPA emissions factors were very good at predicting the mass balance emissions factors for the fossil fuels and to a lesser degree the biofuels. While the AP-42 emissions factors and EPA CFR Title 40 emissions factors are easier to perform, especially in large, full-scale systems, this study illustrated the shortcomings of estimation techniques. 23 refs., 3 figs., 8 tabs.

  2. Plasma sputtering robotic device for in-situ thick coatings of long, small diameter vacuum tubes

    SciTech Connect

    Hershcovitch, A. Blaskiewicz, M.; Brennan, J. M.; Fischer, W.; Liaw, C.-J.; Meng, W.; Todd, R.; Custer, A.; Dingus, A.; Erickson, M.; Jamshidi, N.; Laping, R.; Poole, H. J.

    2015-05-15

    A novel robotic plasma magnetron mole with a 50 cm long cathode was designed, fabricated, and operated. The reason for this endeavor is to alleviate the problems of unacceptable resistive heating of stainless steel vacuum tubes in the BNL Relativistic Heavy Ion Collider (RHIC). The magnetron mole was successfully operated to copper coat an assembly containing a full-size, stainless steel, cold bore, RHIC magnet tubing connected to two types of RHIC bellows, to which two additional pipes made of RHIC tubing were connected. To increase the cathode lifetime, a movable magnet package was developed, and the thickest possible cathode was made, with a rather challenging target to substrate (de facto anode) distance of less than 1.5 cm. Achieving reliable steady state magnetron discharges at such a short cathode to anode gap was rather challenging, when compared to commercial coating equipment, where the target to substrate distance is 10's cm; 6.3 cm is the lowest experimental target to substrate distance found in the literature. Additionally, the magnetron developed during this project provides unique omni-directional uniform coating. The magnetron is mounted on a carriage with spring loaded wheels that successfully crossed bellows and adjusted for variations in vacuum tube diameter, while keeping the magnetron centered. Electrical power and cooling water were fed through a cable bundle. The umbilical cabling system is driven by a motorized spool. Excellent coating adhesion was achieved. Measurements indicated that well-scrubbed copper coating reduced secondary electron yield to 1, i.e., the problem of electron clouds can be eliminated. Room temperature RF resistivity measurement indicated that a 10 μm copper coated stainless steel RHIC tube has a conductivity close to that of pure copper tubing. Excellent coating adhesion was achieved. The device details and experimental results are described.

  3. Plasma Sputtering Robotic Device for In-Situ Thick Coatings of Long, Small Diameter Vacuum Tubes

    NASA Astrophysics Data System (ADS)

    Hershcovitch, Ady

    2014-10-01

    A novel robotic plasma magnetron mole with a 50 cm long cathode was designed fabricated & operated. Reason for this endeavor is to alleviate the problems of unacceptable ohmic heating of stainless steel vacuum tubes and of electron clouds, due to high secondary electron yield (SEY), in the BNL Relativistic Heavy Ion Collider (RHIC). The magnetron mole was successfully operated to copper coat an assembly containing a full-size, stainless steel, cold bore, RHIC magnet tubing connected to two types of RHIC bellows, to which two additional pipes made of RHIC tubing were connected. To increase cathode lifetime, movable magnet package was developed, and thickest possible cathode was made, with a rather challenging target to substrate (de facto anode) distance of less than 1.5 cm. Achieving reliable steady state magnetron discharges at such a short cathode to anode gap was rather challenging, when compared to commercial coating equipment, where the target to substrate distance is 10's cm; 6.3 cm is the lowest experimental target to substrate distance found in the literature. Additionally, the magnetron developed during this project provides unique omni-directional uniform coating. The magnetron is mounted on a carriage with spring loaded wheels that successfully crossed bellows and adjusted for variations in vacuum tube diameter, while keeping the magnetron centered. Electrical power and cooling water were fed through a cable bundle. The umbilical cabling system is driven by a motorized spool. Excellent coating adhesion was achieved. Measurements indicated that well-scrubbed copper coating reduced SEY to 1, i.e., the problem of electron clouds can be eliminated. Room temperature RF resistivity measurement indicated that 10 μm Cu coated stainless steel RHIC tube has conductivity close to that of pure copper tubing. Excellent coating adhesion was achieved. Device detail and experimental results will be presented. Work supported by Brookhaven Science Associates, LLC under

  4. The effect of alternative amines on the rate of boiler tube fouling. Final report

    SciTech Connect

    Turner, C.W.; Klimas, S.J.

    1997-09-01

    Deposition rates were measured for magnetite and hematite particles depositing onto Alloy 600 surfaces, and for magnetite particles depositing onto surfaces prefouled with sintered porous magnetite deposits. The measurements were made in a high-temperature loop, under typical nuclear steam generator operating conditions, with pH controlled using morpholine, ethanolamine, ammonia, dimethylamine, or potassium hydroxide. The deposition rate was compared as a function of the particle type, tube surface morphology, and the reagent used for pH control. The deposition rates were measured for steam qualities ranging up to 50%. The conclusions drawn from this program are: the particle deposition rate of hematite is about an order of magnitude greater than the rate for magnetite on bare Inconel 600 surfaces; the identify of the amine used for pH control affects the deposition rate, the lowest deposition rate is obtained when dimethylamine is used for pH control; the deposition rate of magnetite increases with the increasing concentration of amine (at constant pH); under reducing conditions with no detectable oxygen and with free hydrazine, the deposition rate of hematite decreases towards the value for magnetite; the particle deposition rate can be affected by the surface morphology; the deposition rate is significantly higher on surfaces covered with porous deposits; the heat transfer mechanism and steam quality strongly affect the deposition rate, the deposition rate increases abruptly at higher steam qualities; and there is no evidence that the volatility of the amine affects the deposition behavior.

  5. Anti-Reflective Coating On Borosilicate Long Tubes Industrial Process And Quality Control

    NASA Astrophysics Data System (ADS)

    Eisenberg, N.; Ben-Dor, Y.; Warschawski, J. P.

    1989-07-01

    It has been shown that in order to improve the optical efficiency of a solar trough evacuated pipe used for Luz solar electricity generating systems, an appropriate low cost anti-reflective coating process should be implemented in the solar collector production line, and that a dip process is the optimal choice for this application. It is shown in this paper that pumping the coating solution out of the coating container rather than withdrawing the tubes is the most appropriate coating process for Luz's needs. The same method was employed for the second coating solution which was used both for mechanical abrasion resistance improvement and for increasing optical transmissivity. The measuring procedure for quality insurance of the coated tube was investigated thoroughly and an "in-house" technique, including solar simulation and spiral movement of the tested tube, was chosen in preference to the other standard procedures (spectrophotometry, reflectometry). The complete AR coating facility and production procedure is described and the results of the industrial process are analyzed.

  6. Cermet composite thermal spray coatings for erosion and corrosion protection in combustion environments of advanced coal-fired boilers

    SciTech Connect

    Levin, B.F.; DuPont, J.N.; Marder, A.R.

    1996-05-01

    Research is presently being initiated to determine the optimum ceramic/metal combination in thermally sprayed metal matrix composite coatings for erosion and corrosion resistance in new coal-fired boilers. The research will be accomplished by producing model cermet composites using powder metallurgy and electrodeposition methods in which the effect of ceramic/metal combination for the erosion and corrosion resistance will be determined. These results will provide the basis for determining the optimum hard phase constituents` size and volume percent in thermal spray coatings. Thermal spray coatings will be applied by our industrial sponsor and tested in our erosion and corrosion laboratories. During the last quarter, model Ni-Al{sub 2}O{sub 3} powder cermet composites were produced at Idaho National Engineering Laboratory by the Hot Isostatic Pressing (HIP) technique. The composite samples contained 0, 21, 27, 37, and 45 volume percent of Al{sub 2}O{sub 2} in a nickel matrix with an average size of alumina particles of 12 micrometers. The increase in volume fraction of alumina in the nickel matrix from 0 to 45% led to an increase in hardness of these composites from 85 to 180 HV{sub 1000}. The experimental procedure and preliminary microstructural characterization of Ni-Al{sub 2}O{sub 3} composites are presented in this progress report along with plans for the research in coming year. 3 figs.

  7. Fireside corrosion testing of candidate superheater tube alloys, coatings, and claddings - Phase II

    SciTech Connect

    Blough, J.L.; Krawchuk, M.T.; Van Weele, S.F.

    1995-08-01

    A number of developmental and commercial tubing alloys and claddings have previously been exposed in Phase I to laboratory fireside corrosion testing simulating a superheater or reheater in a coal-fired boiler. This program is exposing samples of TP 347, RA-85H, HR-3C, 253MA, Fe{sub 3}Al + 5Cr, 310 modified, NF-709, 690 clad, and 671 clad, which showed good corrosion resistance from Phase 1, to the actual operating conditions of a 250-MW, coal-fired boiler. The samples were installed on air-cooled, retractable corrosion probes, installed in the reheater cavity, and are being controlled to the operating metal temperatures of an existing and advanced-cycle coal-fired boiler. The exposure will continue for 4000, 12,000, and 16,000 hours of operation. After the three exposure times, the samples will be metallurgically examined to determine the wastage rates and mode of attack. The probes were commissioned November 16, 1994. The temperatures are being recorded every 15 minutes, and the weighted average temperature calculated for each sample. Each of the alloys is being exposed to a temperature in each of two temperature bands-1150 to 1260{degrees}F and 1260 to 1325{degrees}F. After 2000 hours of exposure, one of the corrosion probes was cleaned and the wall thicknesses were ultrasonically measured. The alloy performance from the field probes will be discussed.

  8. Fireside corrosion testing of candidate superheater tube alloys, coatings, and claddings -- Phase 2 field testing

    SciTech Connect

    Blough, J.L.; Seitz, W.W.; Girshik, A.

    1998-06-01

    In Phase 1 of this project, laboratory experiments were performed on a variety of developmental and commercial tubing alloys and claddings by exposing them to fireside corrosion tests which simulated a superheater or reheater in a coal-fired boiler. Phase 2 (in situ testing) has exposed samples of 347, RA85H, HR3C, RA253MA, Fe{sub 3}Al + 5Cr, Ta-modified 310, NF 709, 690 clad, 671 clad, and 800HT for up to approximately 16,000 hours to the actual operating conditions of a 250-MW, coal-fired boiler. The samples were installed on air-cooled, retractable corrosion probes, installed in the reheater cavity, and controlled to the operating metal temperatures of an existing and advanced-cycle, coal-fired boiler. Samples of each alloy were exposed for 4,483, 11,348, and 15,883 hours of operation. The present results are for the metallurgical examination of the corrosion probe samples after the full 15,883 hours of exposure. A previous topical report has been issued for the 4,483 hours of exposure.

  9. Comparative High-Temperature Corrosion Behavior of Ni-20Cr Coatings on T22 Boiler Steel Produced by HVOF, D-Gun, and Cold Spraying

    NASA Astrophysics Data System (ADS)

    Kaushal, Gagandeep; Bala, Niraj; Kaur, Narinder; Singh, Harpreet; Prakash, Satya

    2014-01-01

    To protect materials from surface degradations such as wear, corrosion, and thermal flux, a wide variety of materials can be deposited on the materials by several spraying processes. This paper examines and compares the microstructure and high-temperature corrosion of Ni-20Cr coatings deposited on T22 boiler steel by high velocity oxy-fuel (HVOF), detonation gun spray, and cold spraying techniques. The coatings' microstructural features were characterized by means of XRD and FE-SEM/EDS analyses. Based upon the results of mass gain, XRD, and FE-SEM/EDS analyses it may be concluded that the Ni-20Cr coating sprayed by all the three techniques was effective in reducing the corrosion rate of the steel. Among the three coatings, D-gun spray coating proved to be better than HVOF-spray and cold-spray coatings.

  10. Thermocapillary flow in glass tubes coated with photoresponsive layers.

    PubMed

    Vélez-Cordero, J Rodrigo; Velázquez-Benítez, A M; Hernández-Cordero, J

    2014-05-13

    Thermocapillary flow has proven to be a good alternative to induce and control the motion of drops and bubbles in microchannels. Temperature gradients are usually established by implanting metallic heaters adjacent to the channel or by including a layer of photosensitive material capable of absorbing radiative energy. In this work we show that single drops can be pumped through capillaries coated with a photoresponsive composite (PDMS + carbon nanopowder) and irradiated with a light source via an optical fiber. Maximum droplet speeds achieved with this approach were found to be ~300 μm/s, and maximum displacements, around 120% of the droplet length. The heat generation capacity of the coatings was proven having either a complete coating over the capillary surface or a periodic array of pearls of the photoresponsive material along the capillary produced by the so-called Rayleigh-Plateau instability. The effect of the photoresponsive layer thickness and contact angle hysteresis of the solid-liquid interface were found to be important parameters in the photoinduced thermocapillary effect. Furthermore, a linear relationship between the optical intensity I(o) and droplet velocity v was found for a wide range of the former, allowing us to analyze the results and estimate response times for heat transfer using heat conduction theory. PMID:24731004

  11. Adhesion property and high-temperature oxidation behavior of Cr-coated Zircaloy-4 cladding tube prepared by 3D laser coating

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Gil; Kim, Il-Hyun; Jung, Yang-Il; Park, Dong-Jun; Park, Jeong-Yong; Koo, Yang-Hyun

    2015-10-01

    A 3D laser coating technology using Cr powder was developed for Zr-based alloys considering parameters such as: the laser beam power, inert gas flow, cooling of Zr-based alloys, and Cr powder control. This technology was then applied to Zr cladding tube samples to study the effect of Cr coating on the high-temperature oxidation of Zr-based alloys in a steam environment of 1200 °C for 2000s. It was revealed that the oxide layer thickness formed on the Cr-coated tube surface was about 25-times lower than that formed on a Zircaloy-4 tube surface. In addition, both the ring compression and the tensile tests were performed to evaluate the adhesion properties of the Cr-coated sample. Although some cracks were formed on the Cr-coated layer, the Cr-coated layer had not peeled off after the two tests.

  12. Computational Modeling and Assessment Of Nanocoatings for Ultra Supercritical Boilers

    SciTech Connect

    Gandy, David W.; Shingledecker, John P.

    2011-05-11

    Coal-fired power plants are a significant part of the nation's power generating capacity, currently accounting for more than 55% of the country's total electricity production. Extending the reliable lifetimes of fossil fired boiler components and reducing the maintenance costs are essential for economic operation of power plants. Corrosion and erosion are leading causes of superheater and reheater boiler tube failures leading to unscheduled costly outages. Several types of coatings and weld overlays have been used to extend the service life of boiler tubes; however, the protection afforded by such materials was limited approximately one to eight years. Power companies are more recently focused in achieving greater plant efficiency by increasing steam temperature and pressure into the advanced-ultrasupercritical (A-USC) condition with steam temperatures approaching 760°C (1400°F) and operating pressures in excess of 35MPa (5075 psig). Unfortunately, laboratory and field testing suggests that the resultant fireside environment when operating under A-USC conditions can potentially cause significant corrosion to conventional and advanced boiler materials1-2. In order to improve reliability and availability of fossil fired A-USC boilers, it is essential to develop advanced nanostructured coatings that provide excellent corrosion and erosion resistance without adversely affecting the other properties such as toughness and thermal fatigue strength of the component material.

  13. Final Scientific/Technical Report "Arc Tube Coating System for Color Consistency"

    SciTech Connect

    Buelow, Roger; Jenson, Chris; Kazenski, Keith

    2013-03-21

    DOE has enabled the use of coating materials using low cost application methods on light sources to positively affect the output of those sources. The coatings and light source combinations have shown increased lumen output of LED fixtures (1.5%-2.0%), LED arrays (1.4%) and LED powered remote phosphor systems Philips L-Prize lamp (0.9%). We have also demonstrated lifetime enhancements (3000 hrs vs 8000 hrs) and shifting to higher CRI (51 to 65) in metal halide high intensity discharge lamps with metal oxide coatings. The coatings on LEDs and LED products are significant as the market is moving increasingly more towards LED technology. Enhancements in LED performance are demonstrated in this work through the use of available materials and low cost application processes. EFOI used low refractive index fluoropolymers and low cost dipping processes for application of the material to surfaces related to light transmission of LEDs and LED products. Materials included Teflon AF, an amorphous fluorinated polymer and fluorinated acrylic monomers. The DOE SSL Roadmap sets goals for LED performance moving into the future. EFOI's coating technology is a means to shift the performance curve for LEDs. This is not limited to one type of LED, but is relevant across LED technologies. The metal halide work included the use of sol-gel solutions resulting in silicon dioxide and titanium dioxide coatings on the quartz substrates of the metal halide arc tubes. The coatings were applied using low cost dipping processes.

  14. Assessment of factors affecting boiler tube lifetime in waste-fired generators: New opportunities for research and technology development

    SciTech Connect

    Wright, I.; Krause, H.H.

    1996-07-01

    The disposal of municipal solid waste (MSW) is a major problem in numerous communities in the United States. In this country, approximately 195.7 million tons of MSW were produced in 1990 of which 17 percent was recovered for recycling or composting, 16 percent was combusted, and about 67 percent was disposed of in landfills. This paper discusses the combustion of refuse derived fuels and municipal wastes. The corrosion of the alloys used in boilers is described.

  15. Versatile device for in-situ discharge cleaning and multiple coatings of long, small diameter tubes

    SciTech Connect

    Hershcovitch, A.; Blaskiewicz, M.; Brennan, J.M.; Custer, A.; Erickson, M.; Liaw, C.J.; Fischer, Jamshidi, N.; W.; Meng, W.; Poole, H.J.; Sochugov, N.

    2010-05-23

    Electron clouds, which can limit machine performance, have been observed in many accelerators including RHIC at BNL. Additional concern for the RHIC machine, whose vacuum chamber is made from relatively high resistivity 316LN stainless steel, is high wall resistivity that can result in unacceptably high ohmic heating for superconducting magnets. The high resistivity can be addressed with a copper (Cu) coating; a reduction in the secondary electron yield can be achieved with a TiN or amorphous carbon (a-C) coating. Applying such coatings in an already constructed machine is rather challenging. We have been developing a robotic plasma deposition technique for in-situ coating of long, small diameter tubes. The technique entails fabricating a device comprising of staged magnetrons mounted on a mobile mole for deposition of about 5 ?m of Cu followed by about 0.1 ?m of a-C. As a first step, a 15-cm Cu cathode magnetron was designed, fabricated, and 30-cm long samples of the RHIC pipe have been coated with 2 ?m to 5.6 ?m of copper. Deposition rates of up to 92 A/sec with an average coating rate of 30 A/sec were measured. Effects on RF resistivity is also to be measured.

  16. Studies on Hot Corrosion of the Microstructurally Different Regions of 2.25Cr-1Mo (T22) Boiler Tube Steel Weldment

    NASA Astrophysics Data System (ADS)

    Kumar, Ravindra; Tewari, V. K.; Prakash, Satya

    2009-10-01

    This study examines the effect of microstructurally different regions on the hot corrosion of tungsten inert gas weldment in 2.25Cr-1Mo (T22) boiler tube steel. Various regions of weldment were oxidized in molten salt Na2SO4-60% V2O5 environment at 900 °C. The base metal was found to oxidize at much higher rates than the weld metal and the heat-affected zone. Oxide scales formed in the three regions were compared by scanning electron microscopy with energy dispersive of X-ray analysis, X-ray diffraction pattern, and electron probe microanalysis. The research investigates the formation of inner scales with free Cr over the HAZ.

  17. Computational Modeling and Assessment Of Nanocoatings for Ultra Supercritical Boilers

    SciTech Connect

    David W. Gandy; John P. Shingledecker

    2011-04-11

    Forced outages and boiler unavailability in conventional coal-fired fossil power plants is most often caused by fireside corrosion of boiler waterwalls. Industry-wide, the rate of wall thickness corrosion wastage of fireside waterwalls in fossil-fired boilers has been of concern for many years. It is significant that the introduction of nitrogen oxide (NOx) emission controls with staged burners systems has increased reported waterwall wastage rates to as much as 120 mils (3 mm) per year. Moreover, the reducing environment produced by the low-NOx combustion process is the primary cause of accelerated corrosion rates of waterwall tubes made of carbon and low alloy steels. Improved coatings, such as the MCrAl nanocoatings evaluated here (where M is Fe, Ni, and Co), are needed to reduce/eliminate waterwall damage in subcritical, supercritical, and ultra-supercritical (USC) boilers. The first two tasks of this six-task project-jointly sponsored by EPRI and the U.S. Department of Energy (DE-FC26-07NT43096)-have focused on computational modeling of an advanced MCrAl nanocoating system and evaluation of two nanocrystalline (iron and nickel base) coatings, which will significantly improve the corrosion and erosion performance of tubing used in USC boilers. The computational model results showed that about 40 wt.% is required in Fe based nanocrystalline coatings for long-term durability, leading to a coating composition of Fe-25Cr-40Ni-10 wt.% Al. In addition, the long term thermal exposure test results further showed accelerated inward diffusion of Al from the nanocrystalline coatings into the substrate. In order to enhance the durability of these coatings, it is necessary to develop a diffusion barrier interlayer coating such TiN and/or AlN. The third task 'Process Advanced MCrAl Nanocoating Systems' of the six-task project jointly sponsored by the Electric Power Research Institute, EPRI and the U.S. Department of Energy (DE-FC26-07NT43096)- has focused on processing of

  18. Feasibility study of aluminum beam tube for the collider: An option for no-coating and no-liner

    SciTech Connect

    Chou, W.

    1994-07-01

    This report proposes to use a single-layer beam tube made of high strength, high resistivity aluminum alloy (such as 7039-T61 or A7N01) to replace the double-layer copper coated stainless steel tube in the SSC Collider. The main reasons are: (1) a potential saving of about $23 million which is basically the baseline cost of the copper coating and (2) the use of an extruded aluminum tube consisting of a beam chamber and a pumping chamber may solve the vacuum problem without any liner.

  19. Evaluation of chromic acid anodized aluminum foil coated composite tubes for the Space Station truss structure

    NASA Technical Reports Server (NTRS)

    Dursch, Harry W.; Slemp, Wayne S.

    1988-01-01

    This paper describes the development and evaluation of chromic acid anodized (CAA) Al foil as a protective and thermal control coating for graphite/epoxy tubes designed for the Space Station truss structure. Special consideration is given to the development of solar-absorptance and thermal-emittance properties required of Al foil, the development of CAA parameters necessary to achieve these optical properties, and the atomic oxygen and UV testing of CAA Al foil. Results showed that 0.003-in CAA Al foil cocured or secondary bonded to graphite/epoxy tubes with thin epoxy film adhesive retains excellent bond strength and provides a superior protective and thermal control coating to the LEO environment. Processes were developed for CAA Al foils long enough to continuously wrap the 23-ft-long diagonal struts of the Space Station truss structure. Specifications are presented for the processes of chromic acid anodizing of Al foil and for the bonding of anodized Al foil to graphite/epoxy tubes.

  20. Conduction cooled tube supports

    DOEpatents

    Worley, Arthur C.; Becht, IV, Charles

    1984-01-01

    In boilers, process tubes are suspended by means of support studs that are in thermal contact with and attached to the metal roof casing of the boiler and the upper bend portions of the process tubes. The support studs are sufficiently short that when the boiler is in use, the support studs are cooled by conduction of heat to the process tubes and the roof casing thereby maintaining the temperature of the stud so that it does not exceed 1400.degree. F.

  1. In-tube magnetic solid phase microextraction of some fluoroquinolones based on the use of sodium dodecyl sulfate coated Fe3O4 nanoparticles packed tube.

    PubMed

    Manbohi, Ahmad; Ahmadi, Seyyed Hamid

    2015-07-23

    In-tube magnetic solid phase microextraction (in-tube MSPME) of fluoroquinolones from water and urine samples based on the use of sodium dodecyl sulfate (SDS) coated Fe3O4 nanoparticles packed tube has been reported. After the preparation of Fe3O4 nanoparticles (NPs) by a batch synthesis, these NPs were introduced into a stainless steel tube by a syringe and then a strong magnet was placed around the tube, so that the Fe3O4 NPs were remained in the tube and the tube was used in the in-tube SPME-HPLC/UV for the analysis of fluoroquinolones in water and urine samples. Plackett-Burman design was employed for screening the variables significantly affecting the extraction efficiency. Then, the significant factors were more investigated by Box-Behnken design. Calibration curves were linear (R(2)>0.990) in the range of 0.1-1000μgL(-1) for ciprofloxacin (CIP) and 0.5-500μgL(-1) for enrofloxacin (ENR) and ofloxacin (OFL), respectively. LODs for all studied fluoroquinolones ranged from 0.01 to 0.05μgL(-1). The main advantages of this method were rapid and easy automation and analysis, short extraction time, high sensitivity, possibility of fully sorbent collection after analysis, wide linear range and no need to organic solvents in extraction. PMID:26231896

  2. TiN-based coatings on fuel cladding tubes for advanced nuclear reactors

    SciTech Connect

    Ickchan Kim; Fauzia Khatkhatay; Liang Jiao; Greg Swadener; James Cole; Jian Gan; Haiyan Wang

    2012-10-01

    Titanium nitride (TiN) thin films are coated on HT-9 and MA957 fuel cladding tubes and bars to explore their mechanical strength, thermal stability, diffusion barrier properties, and thermal conductivity properties. The ultimate goal is to implement TiN as an effective diffusion barrier to prevent the inter-diffusion between the nuclear fuel and the cladding material, and thus lead to a longer life time of the cladding tubes. Mechanical tests including hardness and scratch tests for the samples before and after thermal cycle tests show that the films have a high hardness of 28 GPa and excellent adhesion properties despite the thermal treatment. Thermal conductivity measurements demonstrate that the thin TiN films have very minimal impact on the overall thermal conductivity of the MA957 and HT9 substrates, i.e., the thermal conductivity of the uncoated HT-9 and MA957 substrates was 26.25 and 28.44 W m-1K-1 , and that of the coated ones was 26.21 and 28.38 W m-1K-1, respectively. A preliminary Ce diffusion test on the couple of Ce/TiN/HT-9 suggests that TiN has excellent material compatibility and good diffusion barrier properties.

  3. Standard specification for seamless ferritic and austenitic alloy-steel boiler, superheater, and heat-exchanger tubes. ASTM standard

    SciTech Connect

    1996-04-01

    This specification is under the jurisdiction of ASTM Committee A-1 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.10 on Tubing. Current edition approved Oct. 10 and Nov. 10, 1995. 1995 and was published April 1996. Originally published as A 213-39T. Last previous edition was A 213/A 213M-94b.

  4. Cermet composite thermal spray coatings for erosion and corrosion protection in combustion environments of advanced coal-fired boilers. Semiannual technical report, January 14, 1997--August 14, 1997

    SciTech Connect

    Schorr, B.S.; Levin, B.F.; DuPont, J.N.; Marder, A.R.

    1997-08-31

    Research is presently being conducted to determine the optimum ceramic/metal combination in thermally sprayed metal matrix composite coatings for erosion and corrosion resistance in new coal-fired boilers. The research will be accomplished by producing model cermet composites using powder metallurgy and electrodeposition methods in which the effect of ceramic/metal combination for the erosion and corrosion resistance will be determined. These results will provide the basis for determining the optimum hard phase constituent size and volume percent in thermal spray coatings. Thermal spray coatings will be applied by our industrial sponsor and tested in our erosion and corrosion laboratories. Bulk powder processed Ni-Al{sub 2}O{sub 3} composites were produced at Idaho National Engineering Laboratory. The composite samples contained 0, 21, 27, 37, and 45 volume percent Al{sub 2}O{sub 3} with an average particle size of 12 um. Also, to deposit model Ni-Al{sub 2}O{sub 3} coatings, an electrodeposition technique was developed and coatings with various volume fractions (0-35%) of Al{sub 2}O{sub 3} were produced. The powder and electrodeposition processing of Ni-Al{sub 2}O{sub 3} Composites provide the ability to produce two phase microstructure without changing the microstructure of the matrix material. Therefore, the effect of hard second phase particles size and volume fraction on erosion resistance could be analyzed.

  5. Immunoassay using /sup 125/I- or enzyme-labeled protein A and antigen-coated tubes

    SciTech Connect

    Gee, A.P.; Langone, J.J.

    1981-09-15

    Antigen-coated plastic tubes were used with /sup 125/I- or enzyme-labeled stapylococcal protein A in a general immunoassay method for antigens and haptens. Protein A reacts with immunoglobulin G(IgG) regardless of antibody specificity at sites distal to the antigen combining site and does not inhibit the immune reaction. It therefore serves as a general tracer and its use eliminates the need to purify and to label individual components for each assay. Macromolecular antigens were bound to polystyrene or polypropylene tubes by direct passive absorption. Haptens with free carboxyl groups were bound covalently to poly-L-lysine and these conjugates passively absorbed to the tube surface. Optimal assay conditions were established for the quantitative determination of immunoglobulins and the folate derivatives, methotrexate and 5-methyltetrahydrofolate, using /sup 125/I-labeled protein A or protein A labeled with alkaline phosphatase. The method has been used to estimate levels of IgG, IgA, Igm, and IgE in serum in volumes up to 1 ml.

  6. 49 CFR 230.61 - Arch tubes, water bar tubes, circulators and thermic siphons.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MAINTENANCE STANDARDS Boilers and Appurtenances Washing Boilers § 230.61 Arch tubes, water bar tubes, circulators and thermic siphons. (a) Frequency of cleaning. Each time the boiler is washed, arch tubes and water bar tubes shall thoroughly be cleaned mechanically, washed, and inspected. Circulators and...

  7. Oxy-Combustion Boiler Material Development

    SciTech Connect

    Michael Gagliano; Andrew Seltzer; Hans Agarwal; Archie Robertson; Lun Wang

    2012-01-31

    Under U.S. Department of Energy Cooperative Agreement No. DE-NT0005262 Foster Wheeler North America Corp conducted a laboratory test program to determine the effect of oxy-combustion on boiler tube corrosion. In this program, CFD modeling was used to predict the gas compositions that will exist throughout and along the walls of air-fired and oxy-fired boilers operating with low to high sulfur coals. Test coupons of boiler tube materials were coated with deposits representative of those coals and exposed to the CFD predicted flue gases for up to 1000 hours. The tests were conducted in electric tube furnaces using oxy-combustion and air-fired flue gases synthesized from pressurized cylinders. Following exposure, the test coupons were evaluated to determine the total metal wastage experienced under air and oxy-combustions conditions and materials recommendations were made. Similar to air-fired operation, oxy-combustion corrosion rates were found to vary with the boiler material, test temperature, deposit composition, and gas composition. Despite this, comparison of air-fired and oxy-fired corrosion rates showed that oxy-firing rates were, for the most part, similar to, if not lower than those of air-firing; this finding applied to the seven furnace waterwall materials (wrought and weld overlay) and the ten superheater/reheater materials (wrought and weld overlay) that were tested. The results of the laboratory oxy-combustion tests, which are based on a maximum bulk flue gas SO{sub 2} level of 3200 ppmv (wet) / 4050 ppmv (dry), suggest that, from a corrosion standpoint, the materials used in conventional subcritical and supercritical, air-fired boilers should also be suitable for oxy-combustion retrofits. Although the laboratory test results are encouraging, they are only the first step of a material evaluation process and it is recommended that follow-on corrosion tests be conducted in coal-fired boilers operating under oxy-combustion to provide longer term (one to

  8. Oxy-Combustion Boiler Material Development

    SciTech Connect

    Gagliano, Michael; Seltzer, Andrew; Agarwal, Hans; Robertson, Archie; Wang, Lun

    2012-01-31

    Under U.S. Department of Energy Cooperative Agreement No. DE-NT0005262 Foster Wheeler North America Corp conducted a laboratory test program to determine the effect of oxy-combustion on boiler tube corrosion. In this program, CFD modeling was used to predict the gas compositions that will exist throughout and along the walls of air-fired and oxy-fired boilers operating with low to high sulfur coals. Test coupons of boiler tube materials were coated with deposits representative of those coals and exposed to the CFD predicted flue gases for up to 1000 hours. The tests were conducted in electric tube furnaces using oxy-combustion and air-fired flue gases synthesized from pressurized cylinders. Following exposure, the test coupons were evaluated to determine the total metal wastage experienced under air and oxy-combustions conditions and materials recommendations were made. Similar to air-fired operation, oxy-combustion corrosion rates were found to vary with the boiler material, test temperature, deposit composition, and gas composition. Despite this, comparison of air-fired and oxy-fired corrosion rates showed that oxy-firing rates were, for the most part, similar to, if not lower than those of air-firing; this finding applied to the seven furnace waterwall materials (wrought and weld overlay) and the ten superheater/reheater materials (wrought and weld overlay) that were tested. The results of the laboratory oxy-combustion tests, which are based on a maximum bulk flue gas SO2 level of 3200 ppmv (wet) / 4050 ppmv (dry), suggest that, from a corrosion standpoint, the materials used in conventional subcritical and supercritical, air-fired boilers should also be suitable for oxy-combustion retrofits. Although the laboratory test results are encouraging, they are only the first step of a material evaluation process and it is recommended that follow-on corrosion tests be conducted in coal-fired boilers operating under oxy-combustion to provide longer term (one to two year

  9. Silver-Coated Teflon Tubes for Waveguiding at 1-2 THz

    NASA Astrophysics Data System (ADS)

    Navarro-Cía, Miguel; Melzer, Jeffrey E.; Harrington, James A.; Mitrofanov, Oleg

    2015-06-01

    Realization of single-mode low-loss waveguides for 1.0-2.0 THz remains a challenging problem due to large absorption in most dielectrics and ohmic losses in metals. To address this problem, we investigate dielectric-lined hollow metallic waveguides fabricated by coating 1-mm diameter 38-μm-thick polytetrafluoroethylene tubes with silver. These waveguides support a hybrid HE11 mode, which exhibits low attenuation and low dispersion. Quasi-single-mode propagation is achieved in the band of 1.0-1.6 THz, in which the hybrid HE11 mode is supported by the waveguide. In this band, the experimentally measured loss is ~20 dB/m (~0.046 cm-1), whereas the numerically computed loss is ~7 dB/m (~0.016 cm-1). The difference is attributed to additional losses in the dielectric layer, which can be reduced by using alternative polymers.

  10. Effect of anti-corrosion coating on the thermal characteristics of a louvered finned tube heat exchanger under dehumidifying conditions

    SciTech Connect

    Fu, W.L.; Wang, C.C.; Chang, W.R.; Chang, C.T.

    1995-12-31

    An experimental study on four louver fin tube heat exchangers were carried out in a forced-circulation wind tunnel. The heat exchangers consist of three anti-corrosion coated louver fin heat exchangers with various fin pitches and one non-coated louver fin heat exchanger. The effect of anti-corrosion coating on both dry and wet operating conditions were investigated. In addition, the effect of fin pitches was also shown in the present investigation. Data were presented in terms of total j factors, sensible j factors and friction factor f.

  11. [Study on the determination of trace gallium in molybdenum-coated pyrolytic graphite tube by electrothermal absorption spectrometry].

    PubMed

    Huang, Yu-an; Zhou, Fang-qin; Long, Si-hua; Yang, Liu

    2004-02-01

    The effects on gallium atomization in the pyrolytic graphite tube imposed by different matrix modifiers and different coatings were discussed detailedly in this paper. In the presence of matrix modifier of Ni(NO3)2 the matrix interference was eliminated efficiently. The pyrolytic graphite tubes were coated differently with lanthanum, zirconium, and molybdenum to avoid producing gallium carbide. Results showed that the tube with molybdenum coating was the best. On this basis, the mechanism of gallium atomization in the molybdenum-coated pyrolytic graphite tube using Ni(NO3)2 as a matrix modifier was studied furthermore; in addition, the parameters of the operation were optimized. As a result, a new method improved in many aspects was developed to detect trace gallium in complicated sample of gangue. The outcomes of practical applications indicated that the method could satisfy the requests of analysis and that the manipulations were simple to achieve. The characteristic content, the detection limit, and the adding recoveries were 2.12 x 10(-11) g, 1.4 x 10(-10) g and 97.4%-102.7% respectively, and the relative standard deviation was less than or equal to 3.6% (n = 11). PMID:15769028

  12. Corrosion resistant coatings for silicon carbide heat exchanger tubes -- Volume 3. Final report

    SciTech Connect

    Boss, D.E.

    1996-06-07

    The development of a silicon carbide (SiC) heat exchanger is a critical step in the development of the Externally-Fired Combined Cycle (EFCC) power system. SiC is the only material that provides the necessary combination of resistance to creep, thermal shock, and oxidation. While the SiC structure materials provide the thermomechanical and thermophysical properties needed for an efficient system, the mechanical properties of the SiC tubes are severely degraded through corrosion by the coal combustion products. To obtain the necessary service life of thousands of hours at temperature, a protective coating is needed that is stable with both the SiC tube and the coal combustion products, resists erosion from the particle laden gas stream, is thermal shock resistant, adheres to SiC during repeated thermal shocks (start-up, process upsets, shut-down), and allows the EFCC system to be cost competitive. This demanding set of technical performance and cost drivers was used in reviewing and selecting candidate protective materials. After a review of open literature, discussion with leading researchers in materials for coal combustion environments, and preliminary thermodynamic studies, a total of ten materials were identified for future study that were grouped into three categories: alumina-based materials, materials stable with SiO{sub 2}, and low expansion materials.

  13. Study of mechanical properties and high temperature oxidation behavior of a novel cold-spray Ni-20Cr coating on boiler steels

    NASA Astrophysics Data System (ADS)

    Kaur, Narinder; Kumar, Manoj; Sharma, Sanjeev K.; Kim, Deuk Young; Kumar, S.; Chavan, N. M.; Joshi, S. V.; Singh, Narinder; Singh, Harpreet

    2015-02-01

    In the current investigation, high temperature oxidation behavior of a novel cold-spray Ni-20Cr nanostructured coating was studied. The nanocrystalline Ni-20Cr powder was synthesized by the investigators using ball milling, which was deposited on T22 and SA 516 steels by cold spraying. The crystallite size based upon Scherrer's formula for the developed coatings was found to be in nano-range for both the substrates. The accelerated oxidation testing was performed in a laboratory tube furnace at a temperature 900 °C under thermal cyclic conditions. Each cycle comprised heating for one hour at 900 °C followed by cooling for 20 min in ambient air. The kinetics of oxidation was established using weight change measurements for the bare and the coated steels. The oxidation products were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS) and X-ray mapping techniques. It was found from the results that the coating was successful in reducing the weight gain of SA213-T22 and SA 516-Grade 70 steel by 71% and 94%, respectively. This may be attributed to relatively denser structure, lower porosity and lower oxide content of the coating. Moreover, the developed nano-structured Ni-20Cr powder coating was found to perform better than its counterpart micron-sized Ni-20Cr powder coating, in terms of offering higher oxidation resistance and hardness.

  14. Looking northwest at central boiler house, with 16" skelp mill ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking northwest at central boiler house, with 16" skelp mill furnace building in foreground. - U.S. Steel National Tube Works, Central Boiler House, Along Monongahela River, McKeesport, Allegheny County, PA

  15. Computation Modeling and Assessment of Nanocoatings for Ultra Supercritical Boilers

    SciTech Connect

    J. Shingledecker; D. Gandy; N. Cheruvu; R. Wei; K. Chan

    2011-06-21

    Forced outages and boiler unavailability of coal-fired fossil plants is most often caused by fire-side corrosion of boiler waterwalls and tubing. Reliable coatings are required for Ultrasupercritical (USC) application to mitigate corrosion since these boilers will operate at a much higher temperatures and pressures than in supercritical (565 C {at} 24 MPa) boilers. Computational modeling efforts have been undertaken to design and assess potential Fe-Cr-Ni-Al systems to produce stable nanocrystalline coatings that form a protective, continuous scale of either Al{sub 2}O{sub 3} or Cr{sub 2}O{sub 3}. The computational modeling results identified a new series of Fe-25Cr-40Ni with or without 10 wt.% Al nanocrystalline coatings that maintain long-term stability by forming a diffusion barrier layer at the coating/substrate interface. The computational modeling predictions of microstructure, formation of continuous Al{sub 2}O{sub 3} scale, inward Al diffusion, grain growth, and sintering behavior were validated with experimental results. Advanced coatings, such as MCrAl (where M is Fe, Ni, or Co) nanocrystalline coatings, have been processed using different magnetron sputtering deposition techniques. Several coating trials were performed and among the processing methods evaluated, the DC pulsed magnetron sputtering technique produced the best quality coating with a minimum number of shallow defects and the results of multiple deposition trials showed that the process is repeatable. scale, inward Al diffusion, grain growth, and sintering behavior were validated with experimental results. The cyclic oxidation test results revealed that the nanocrystalline coatings offer better oxidation resistance, in terms of weight loss, localized oxidation, and formation of mixed oxides in the Al{sub 2}O{sub 3} scale, than widely used MCrAlY coatings. However, the ultra-fine grain structure in these coatings, consistent with the computational model predictions, resulted in accelerated Al

  16. 49 CFR 230.61 - Arch tubes, water bar tubes, circulators and thermic siphons.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Arch tubes, water bar tubes, circulators and... MAINTENANCE STANDARDS Boilers and Appurtenances Washing Boilers § 230.61 Arch tubes, water bar tubes... water bar tubes shall thoroughly be cleaned mechanically, washed, and inspected. Circulators and...

  17. 49 CFR 230.61 - Arch tubes, water bar tubes, circulators and thermic siphons.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Arch tubes, water bar tubes, circulators and... MAINTENANCE STANDARDS Boilers and Appurtenances Washing Boilers § 230.61 Arch tubes, water bar tubes... water bar tubes shall thoroughly be cleaned mechanically, washed, and inspected. Circulators and...

  18. Source gas depletion in narrow metal tube during internal DLC coating with microwave-excited high-density near plasma

    NASA Astrophysics Data System (ADS)

    Matsui, Ryosuke; Kosaka, Hiroyuki; Umehara, Noritsugu

    2012-10-01

    In internal DLC (Diamond-Like Carbon) coating to mm-sized narrow metal tubes by using MVP (Microwave-sheath Voltage combination Plasma) method, axially uniform distribution of film thickness can be obtained by repeating the depletion and homogenization of source gas in a coated tube during plasma-on time Ton and plasma-off time Toff of pulsed plasma generation, respectively. DLC was deposited to the inner surface of a stainless-steel tube 4.4 mm in inner diameter and 50 mm in length with small holes of φ=0.4 mm fabricated at every 10 mm, where the flow rates of Ar and methane were controlled to be 14 and 2 sccm, respectively, at a total gas pressure of 80 Pa. A pulsed negative voltage of --200 V was applied to the tube at a pulse frequency of 10 Hz and duty ratio of 3.2%, synchronizing a pulsed injection of 2.45-GHz microwaves at the same pulse frequency (Ton=3.2 ms and Toff=96.8 ms). The high-speed camera image showed that the emission (696, 706 nm) from Ar atom was approximately constant during plasma-on time. On the other hand, the emission (468-474 nm) from C2 dimer was decreased until Ton =1.5 ms, and then converged in a constant value; this is ascribed to the consumption of CH4 gas which is considered to be a main source of C2 dimer formation.

  19. Characterization of mechanical properties of hydroxyapatite-silicon-multi walled carbon nano tubes composite coatings synthesized by EPD on NiTi alloys for biomedical application.

    PubMed

    Khalili, Vida; Khalil-Allafi, Jafar; Sengstock, Christina; Motemani, Yahya; Paulsen, Alexander; Frenzel, Jan; Eggeler, Gunther; Köller, Manfred

    2016-06-01

    Release of Ni(1+) ions from NiTi alloy into tissue environment, biological response on the surface of NiTi and the allergic reaction of atopic people towards Ni are challengeable issues for biomedical application. In this study, composite coatings of hydroxyapatite-silicon multi walled carbon nano-tubes with 20wt% Silicon and 1wt% multi walled carbon nano-tubes of HA were deposited on a NiTi substrate using electrophoretic methods. The SEM images of coated samples exhibit a continuous and compact morphology for hydroxyapatite-silicon and hydroxyapatite-silicon-multi walled carbon nano-tubes coatings. Nano-indentation analysis on different locations of coatings represents the highest elastic modulus (45.8GPa) for HA-Si-MWCNTs which is between the elastic modulus of NiTi substrate (66.5GPa) and bone tissue (≈30GPa). This results in decrease of stress gradient on coating-substrate-bone interfaces during performance. The results of nano-scratch analysis show the highest critical distance of delamination (2.5mm) and normal load before failure (837mN) as well as highest critical contact pressure for hydroxyapatite-silicon-multi walled carbon nano-tubes coating. The cell culture results show that human mesenchymal stem cells are able to adhere and proliferate on the pure hydroxyapatite and composite coatings. The presence of both silicon and multi walled carbon nano-tubes (CS3) in the hydroxyapatite coating induce more adherence of viable human mesenchymal stem cells in contrast to the HA coated samples with only silicon (CS2). These results make hydroxyapatite-silicon-multi walled carbon nano-tubes a promising composite coating for future bone implant application. PMID:26897095

  20. Uptake of gaseous formaldehyde onto soil surfaces: a coated-wall flow tube study

    NASA Astrophysics Data System (ADS)

    Li, Guo; Su, Hang; Li, Xin; Meusel, Hannah; Kuhn, Uwe; Pöschl, Ulrich; Shao, Min; Cheng, Yafang

    2015-04-01

    Gaseous formaldehyde (HCHO) is an important intermediate molecule and source of HO2 radicals. However, discrepancies exist between model simulated and observed HCHO concentrations, suggesting missing sources or sinks in the HCHO budget. Multiphase processes on the surface of soil and airborne soil-derived particles have been suggested as an important mechanism for the production/removal of atmospheric trace gases and aerosols. In this work, the uptake of gaseous HCHO on soil surfaces were investigated through coated-wall flow tube experiments with HCHO concentration ranging from 10 to 40 ppbv. The results show that the adsorption of HCHO occurred on soil surfaces, and the uptake coefficient dropped gradually (i.e., by a factor of 5 after 1 hour) as the reactive surface sites were consumed. The HCHO uptake coefficient was found to be affected by the relative humidity (RH), decreasing from (2.4 ± 0.5) × 10-4 at 0% RH to (3.0 ± 0.08) × 10-5 at 70% RH, due to competition of water molecule absorption on the soil surface. A release of HCHO from reacted soil was also detected by applying zero air, suggesting the nature of reversible physical absorption and the existence of an equilibrium at the soil-gas interface. It implies that soil could be either a source or a sink for HCHO, depending on the ambient HCHO concentration. We also develop a Matlab program to calculate the uptake coefficient under laminar flow conditions based on the Cooney-Kim-Davis method.

  1. 35. VIEW LOOKING EAST IN SOUTH END OF EAST BOILER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. VIEW LOOKING EAST IN SOUTH END OF EAST BOILER ROOM. CYLINDRICAL TANKS ARE WORTHINGTON DEAERATORS. THESE REMOVED AIR FROM BOILER FEED WATER TO MINIMIZE CORROSION AND PITTING OF THE BOILER TUBES. AIR REMOVAL ALSO HELPED AVOID THE FORMATION OF FOAM IN THE SYSTEM. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

  2. Bactericidal effects of silver plus titanium dioxide-coated endotracheal tubes on Pseudomonas aeruginosa and Staphylococcus aureus

    PubMed Central

    Tarquinio, Keiko M; Kothurkar, Nikhil K; Goswami, Dharendra Y; Sanders, Ronald C; Zaritsky, Arno L; LeVine, Ann Marie

    2010-01-01

    Purpose: Ventilator-associated pneumonia (VAP) is a nosocomial infection resulting in significant morbidity and mortality. Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) are pathogens associated with VAP. Silver (Ag) coating of endotracheal tubes (ETTs) reduces bacterial colonization, however titanium dioxide (TiO2) coating has not been studied. Methods: Five types of ETT coatings were applied over silica layer: Ag, solgel TiO2, solgel TiO2 with Ag, Degussa P25 TiO2 (Degussa TiO2), and Degussa TiO2 with Ag. After ETTs were incubated with P. aeruginosa or S. aureus; colonization was determined quantitatively. Results: Pseudomonas aeruginosa and S. aureus grew for 5 days on standard ETTs. Compared to standard ETTs, P. aeruginosa growth was significantly inhibited by solgel TiO2 with Ag at 24 hours, and by Degussa TiO2 with Ag at 24 and 48 hours after inoculation. No significant difference in S. aureus growth was observed between the control and any of the five coatings for 5 days. Conclusion: In vitro, solgel TiO2 with Ag and Degussa TiO2 with Ag both attenuated P. aeruginosa growth, but demonstrated no effect on S. aureus colonization. Further studies using alternative coating and incorporating UV light exposure are needed to identify their potential utility in reducing VAP. PMID:20463933

  3. Thermally-induced stresses in graphite-epoxy tubes coated with aluminum foil

    NASA Technical Reports Server (NTRS)

    Knott, Tamara W.; Hyer, M. W.

    1989-01-01

    Thermally-induced stresses in the foil, adhesive, and graphite-epoxy layers of composite tubes with aluminum foil bonded to the inner and outer surface are computed. The thermal effects are due to a temperature decrease from the processing temperature of the material to a temperature felt to represent the space environment, the intended operating environment of the tubes. Tubes fabricated from T300/934 and P75s/934 material systems are considered. The results indicate that the presence of the foil and adhesive have no detrimental effect on the stresses in the tube.

  4. [Determination of trace barium in environmental samples by electric-heated AAS with lanthanum-coated graphite tube].

    PubMed

    Han, Hua-yun; Lin, Lin; Chen, Ke; Wang, Feng

    2002-02-01

    In this paper a new method was established for determination of trace barium in environmental samples by graphite furnace atomic absorption spectrometry. In the presence of matrix modifier magnesium nitrate, the matrix inference was eliminated efficiently. To avoid producing barium carbide, the graphite tubes were coated differently with lanthanum, zirconium, tungsten, molybdenum, and tantalum. Results showed that the tube with lanthanum was the best. The atomization temperature was diminished. The sensitivity was improved, and the tube with lanthanum gave the longest service life. So we used the tube to determine trace barium. The trace barium in Geodchemical Standard Reference Sample Soil-1 (GSS-1) was determined by the new method, the test results showed that the method was reliability and accurate. The method has been used for the determination of trace barium in environmental samples and in water of Yellow River. The detection limit for Ba was 2.1 x 10(-12) g and the relative standard deviation(RSD) was 5.4% for 15 ng.mL-1 Ba. PMID:12940053

  5. Electroplating of nanostructured polyaniline-polypyrrole composite coating in a stainless-steel tube for on-line in-tube solid phase microextraction.

    PubMed

    Asiabi, Hamid; Yamini, Yadollah; Seidi, Shahram; Esrafili, Ali; Rezaei, Fatemeh

    2015-06-01

    In this work, a novel and efficient on-line in-tube solid phase microextraction method followed by high performance liquid chromatography was developed for preconcentration and determination of trace amounts of parabens. A nanostructured polyaniline-polypyrrole composite was electrochemically deposited on the inner surface of a stainless steel tube and used as the extraction phase. Several important factors that influence the extraction efficiency, including type of solid-phase coating, extraction and desorption times, flow rates of the sample solution and eluent, pH, and ionic strength of the sample solution were investigated and optimized. Under the optimal conditions, the limits of detection were in the range of 0.02-0.04 μg L(-1). This method showed good linearity for parabens in the range of 0.07-50 μg L(-1), with coefficients of determination better than 0.998. The intra- and inter-assay precisions (RSD%, n=3) were in the range of 5.9-7.0% and 4.4-5.7% at three concentration levels of 2, 10, and 20 μg L(-1), respectively. The extraction recovery values for the spiked samples were in the acceptable range of 80.3-90.2%. The validated method was successfully applied for analysis of methyl-, ethyl-, and propyl parabens in some water, milk, and juice samples. PMID:25913328

  6. Predictive modelling of boiler fouling

    SciTech Connect

    Not Available

    1992-01-01

    In this reporting period, efforts were initiated to supplement the comprehensive flow field description obtained from the RNG-Spectral Element Simulations by incorporating, in a general framework, appropriate modules to model particle and condensable species transport to the surface. Specifically, a brief survey of the literature revealed the following possible mechanisms for transporting different ash constituents from the host gas to boiler tubes as deserving prominence in building the overall comprehensive model: (1) Flame-volatilized species, chiefly sulfates, are deposited on cooled boiler tubes via the mechanism of classical vapor diffusion. This mechanism is more efficient than the particulate ash deposition, and as a result there is usually an enrichment of condensable salts, chiefly sulfates, in boiler deposits; (2) Particle diffusion (Brownian motion) may account for deposition of some fine particles below 0. 1 mm in diameter in comparison with the mechanism of vapor diffusion and particle depositions, however, the amount of material transported to the tubes via this route is probably small. (3) Eddy diffusion, thermophoretic and electrophoretic deposition mechanisms are likely to have a marked influence in transporting 0.1 to 5[mu]m particles from the host gas to cooled boiler tubes; (4) Inertial impaction is the dominant mechanism in transporting particles above 5[mu]m in diameter to water and steam tubes in pulverized coal fired boiler, where the typical flue gas velocity is between 10 to 25 m/s. Particles above 10[mu]m usually have kinetic energies in excess of what can be dissipated at impact (in the absence of molten sulfate or viscous slag deposit), resulting in their entrainment in the host gas.

  7. Development of a novel graphene/polyaniline electrodeposited coating for on-line in-tube solid phase microextraction of aldehydes in human exhaled breath condensate.

    PubMed

    Li, Yu; Xu, Hui

    2015-05-22

    In this work, we introduced a novel graphene/polyaniline (G/PANI) electrodeposited coating for on-line in-tube solid phase microextraction (IT-SPME) for the first time. The G/PANI coating was prepared on the internal surface of stainless steel tube by a facile in-situ electrodeposition method. The morphology and formation of the composite coating were confirmed by scanning electronic microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Some important experimental parameters that could affect the extraction and separation such as the coating thickness, internal diameter of tube, sampling flow rate as well as sample volume were optimized. The extraction performance of the IT-SPME coating was evaluated systematically. The coating exhibited enhanced mechanical stability, long lifespan, large specific surface area and good biocompatibility compared with polyaniline coating. The on-line IT-SPME method showed higher enrichment efficiency, faster analysis speed and higher automation level than off-line manual mode. Six aldehydes were determined simultaneously with low limits of detection of 0.02-0.04nmolL(-1) and good linearity (R(2)≥0.9920). The method has been applied successfully for the determination of aldehydes in human exhaled breath condensates with good recovery (70-120%) and satisfied reproducibility (relative standard deviation: 1.1-11.9%). This on-line IT-SPME method provides a promising approach for the determination of trace aldehydes with approving sensitivity in human exhaled breath condensates. PMID:25863926

  8. Tritium permeation experiments using reduced activation ferritic/martensitic steel tube and erbium oxide coating

    SciTech Connect

    Takumi Chikada; Masashi Shimada; Robert Pawelko; Takayuki Terai; Takeo Muroga

    2013-09-01

    Low concentration tritium permeation experiments have been performed on uncoated F82H and Er2O3-coated tubular samples in the framework of the Japan-US TITAN collaborative program. Tritium permeability of the uncoated sample with 1.2 ppm tritium showed one order of magnitude lower than that with 100% deuterium. The permeability of the sample with 40 ppm tritium was more than twice higher than that of 1.2 ppm, indicating a surface contribution at the lower tritium concentration. The Er2O3-coated sample showed two orders of magnitude lower permeability than the uncoated sample, and lower permeability than that of the coated plate sample with 100% deuterium. It was also indicated that the memory effect of ion chambers in the primary and secondary circuits was caused by absorption of tritiated water vapor that was generated by isotope exchange reactions between tritium and surface water on the coating.

  9. Properties of Thick Sputtered Ta used for Protective Gun Tube Coatings

    SciTech Connect

    Matson, Dean W.; McClanahan, Edwin D.; Lee, Sabrina L.; Windover, Donald

    2001-10-01

    Thick tantalum coatings were deposited on the bore surfaces of 25 mm I.D. cylindrical gun steel substrates using a high-rate triode sputtering apparatus. Sputtering parameters affecting the tantalum phase and microstructure were investigated. Prior work has indicated that the sputtering gas species and substrate temperature during deposition affect the characteristics of the tantalum coatings. In the work presented here, we report on experimental studies aimed at evaluating additional phase and microstructural effects resulting from changes in sputtering gas species and substrate bias during the deposition. Tantalum deposits of 75 to 140 {mu}m thicknesses were evaluated using x-ray diffraction, optical microscopy, and microindentation hardness measurements. Coatings deposited using krypton gas, a 200 C substrate temperature, and 3.5 mTorr gas pressure also showed little variation when deposited at substrate biases ranging from 50 to 150 V. However, the tantalum coatings produced under similar conditions with an unbiased (floating) substrate were found to be the beta phase of the material and had a columnar microstructure. Beta-phase tantalum was produced at low substrate biases (from 0 to 50 V) when using Xe as the sputtering gas. Both phase and microstructure of the tantalum coating could be altered in mid-run by adjusting the sputtering parameters and appeared independent of the phase and microstructure of the underlying coating.

  10. Novel Surface Modification Method for Ultrasupercritical Coal-Fired Boilers

    SciTech Connect

    Xiao, T. Danny

    2013-05-22

    US Department of Energy seeks an innovative coating technology for energy production to reduce the emission of SOx, NOx, and CO2 toxic gaseous species. To realize this need, Inframat Corporation (IMC) proposed an SPS thermal spray coating technique to produce ultrafine/nanocoatings that can be deposited onto the surfaces of high temperature boiler tubes, so that higher temperatures of boiler operation becomes possible, leading to significantly reduced emission of toxic gaseous species. It should be noted that the original PI was Dr. Xinqing Ma, who after 1.5 year conducting this project left Inframat in December, 2008. Thus, the PI was transferred to Dr. Danny Xiao, who originally co-authored the proposal with Dr. Ma, in order to carry the project into a completion. Phase II Objectives: The proposed technology has the following attributes, including: (1). Dispersion of a nanoparticle or alloyed particle in a solvent to form a uniform slurry feedstock; (2). Feeding of the slurry feedstock into a thermal spray flame, followed by deposition of the slurry feedstock onto substrates to form tenacious nanocoatings; (3). High coating performance: including high bonding strength, and high temperature service life in the temperature range of 760oC/1400oF. Following the above premises, our past Phase I project has demonstrated the feasibility in small scale coatings on boiler substrates. The objective of this Phase II project was to focus on scale-up the already demonstrated Phase I work for the fabrication of SPS coatings that can satisfy DOE's emission reduction goals for energy production operations. Specifically, they are: (1). Solving engineering problems to scale-up the SPS-HVOF delivery system to a prototype production sub-delivery system; (2). Produce ultrafine/nanocoatings using the scale-up prototype system; (3). Demonstrate the coated components using the scale-up device having superior properties. Proposed Phase II Tasks: In the original Phase II proposal, we have

  11. Polydopamine-coated eppendorf tubes for Ti⁴⁺ immobilization for selective enrichment of phosphopeptides.

    PubMed

    Shi, Chenyi; Deng, Chunhui; Zou, ShiEn; Zhang, Xiangmin

    2014-09-01

    Mass spectrometric technique has emerged as a preferred technique in the analysis of protein phosphorylation. Owing to the low stoichiometry of phosphopeptides and the signal suppression effect by non-phosphopeptides, there is a demand for efficient enrichment of phosphopeptides. The selective enrichment of phosphopeptides in modified eppendorf tubes prior to mass spectrometry analysis, which can minimize sample loss as well as nonspecific interferences effectively, has become a hot topic in current proteomics field. In our work, an easy-to-use phosphopeptide-selective eppendorf tube was initially prepared, with its inner surface being modified with a Ti(4+)-immobilized polydopamine (PDA) layer. The unique Ti(4+)-immobilized PDA-modified eppendorf tubes (EP tube@PDA-Ti(4+)) are investigated for its application in selective enrichment of phosphopeptides from complex biological samples. Due to the high Ti(4+) loading amount on the surface of PDA, the EP tube@PDA-Ti(4+) exhibits remarkable phosphopeptide enrichment ability in protein digests and human serum, which presents a powerful evidence for its high selectivity in detecting the low-abundance phosphopeptides from complex biological samples. PMID:24913861

  12. Preparation and evaluation of a novel molecularly imprinted polymer coating for selective extraction of indomethacin from biological samples by electrochemically controlled in-tube solid phase microextraction.

    PubMed

    Asiabi, Hamid; Yamini, Yadollah; Seidi, Shahram; Ghahramanifard, Fazel

    2016-03-24

    In the present work, an automated on-line electrochemically controlled in-tube solid-phase microextraction (EC-in-tube SPME) coupled with HPLC-UV was developed for the selective extraction and preconcentration of indomethacin as a model analyte in biological samples. Applying an electrical potential can improve the extraction efficiency and provide more convenient manipulation of different properties of the extraction system including selectivity, clean-up, rate, and efficiency. For more enhancement of the selectivity and applicability of this method, a novel molecularly imprinted polymer coated tube was prepared and applied for extraction of indomethacin. For this purpose, nanostructured copolymer coating consisting of polypyrrole doped with ethylene glycol dimethacrylate was prepared on the inner surface of a stainless-steel tube by electrochemical synthesis. The characteristics and application of the tubes were investigated. Electron microscopy provided a cross linked porous surface and the average thickness of the MIP coating was 45 μm. Compared with the non-imprinted polymer coated tubes, the special selectivity for indomethacin was discovered with the molecularly imprinted coated tube. Moreover, stable and reproducible responses were obtained without being considerably influenced by interferences commonly existing in biological samples. Under the optimal conditions, the limits of detection were in the range of 0.07-2.0 μg L(-1) in different matrices. This method showed good linearity for indomethacin in the range of 0.1-200 μg L(-1), with coefficients of determination better than 0.996. The inter- and intra-assay precisions (RSD%, n = 3) were respectively in the range of 3.5-8.4% and 2.3-7.6% at three concentration levels of 7, 70 and 150 μg L(-1). The results showed that the proposed method can be successfully applied for selective analysis of indomethacin in biological samples. PMID:26944991

  13. Novel techniques and devices for in-situ film coatings of long, small diameter tubes or elliptical and other surface contours

    DOE PAGESBeta

    Hershcovitch, Ady; Blaskiewicz, Michael; Brennan, Joseph Michael; Fischer, Wolfram; Liaw, Chong -Jer; Meng, Wuzhang; Todd, Robert; Custer, Art; Dingus, Aaron; Erikson, Mark; et al

    2015-07-30

    In this study, devices and techniques that can, via physical vapor deposition,coat various surface contours or very long small aperture pipes, are described. Recently, a magnetron mole was developed in order to in-situ coat accelerator tube sections of the Brookhaven National Lab relativistic heavy ion collider that have 7.1 cm diameter with access points that are 500 m apart, for copper coat the accelerator vacuum tube in order to alleviate the problems of unacceptable ohmic heating and of electron clouds. A magnetron with a 50 cm long cathode was designed fabricated and successfully operated to copper coat a whole assemblymore » containing a full-size, stainless steel, cold bore, of the accelerator magnet tubing connected to two types bellows, to which two additional pipes made of accelerator tubing were connected. The magnetron is mounted on a carriage with spring loaded wheels that successfully crossed bellows and adjusted for variations in vacuum tube diameter, while keeping the magnetron centered. Electrical power and cooling water were fed through a cable bundle. The umbilical cabling system, which is enclosed in a flexible braided metal sleeve, is driven by a motorized spool. To increase cathode lifetime, movable magnet package was developed, and thickest possible cathode was made, with a rather challenging target to substrate distance of less than 1.5 cm. Optimized process to ensure excellent adhesion was developed. Coating thickness of 10 μm Cu passed all industrial tests and even exceeded maximum capability of a 12 kg pull test fixture. Room temperature radio frequency (RF) resistivity measurement indicated that 10 μm Cu coated stainless steel accelerator tube has conductivity close to copper tubing. Work is in progress to repeat the RF resistivity measurement at cryogenic temperatures. Over 20 years ago, a device using multi axis robotic manipulators controlling separate robotic assemblies resulted in nine-axes of motion combined with conformal

  14. Novel techniques and devices for in-situ film coatings of long, small diameter tubes or elliptical and other surface contours

    SciTech Connect

    Hershcovitch, Ady; Blaskiewicz, Michael; Brennan, Joseph Michael; Fischer, Wolfram; Liaw, Chong -Jer; Meng, Wuzhang; Todd, Robert; Custer, Art; Dingus, Aaron; Erikson, Mark; Jamshidi, Nader; Poole, Henry Joe

    2015-07-30

    In this study, devices and techniques that can, via physical vapor deposition,coat various surface contours or very long small aperture pipes, are described. Recently, a magnetron mole was developed in order to in-situ coat accelerator tube sections of the Brookhaven National Lab relativistic heavy ion collider that have 7.1 cm diameter with access points that are 500 m apart, for copper coat the accelerator vacuum tube in order to alleviate the problems of unacceptable ohmic heating and of electron clouds. A magnetron with a 50 cm long cathode was designed fabricated and successfully operated to copper coat a whole assembly containing a full-size, stainless steel, cold bore, of the accelerator magnet tubing connected to two types bellows, to which two additional pipes made of accelerator tubing were connected. The magnetron is mounted on a carriage with spring loaded wheels that successfully crossed bellows and adjusted for variations in vacuum tube diameter, while keeping the magnetron centered. Electrical power and cooling water were fed through a cable bundle. The umbilical cabling system, which is enclosed in a flexible braided metal sleeve, is driven by a motorized spool. To increase cathode lifetime, movable magnet package was developed, and thickest possible cathode was made, with a rather challenging target to substrate distance of less than 1.5 cm. Optimized process to ensure excellent adhesion was developed. Coating thickness of 10 μm Cu passed all industrial tests and even exceeded maximum capability of a 12 kg pull test fixture. Room temperature radio frequency (RF) resistivity measurement indicated that 10 μm Cu coated stainless steel accelerator tube has conductivity close to copper tubing. Work is in progress to repeat the RF resistivity measurement at cryogenic temperatures. Over 20 years ago, a device using multi axis robotic manipulators controlling separate robotic assemblies resulted in nine-axes of motion combined with conformal shape of the

  15. 13. RW Meyer Sugar Mill: 18761889. Engine and boiler house, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. RW Meyer Sugar Mill: 1876-1889. Engine and boiler house, ca. 1881. Locomotive-type, fire-tube, portable boiler, no. I model. Manufactured by Ames Iron Works, Oswego, New York, 1879. 120 lbs./sq. in. working pressure, 66 sq. ft. heating surface in tubes. View: Historical view, 1934, from T.T. Waterman Collection, Hawaiian Sugar Planters' Association. View shows engine and boiler house structure intact. The water and pressure gauge to the right of the boiler are in more complete condition than in 1978 views. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

  16. Fireside corrosion testing of candidate superheater tube alloys, coatings, and claddings. Final report

    SciTech Connect

    Van Weele, S.

    1991-08-01

    Fireside corrosion, caused by liquid alkali-iron trisulfates, has been an obstacle to higher steam temperatures and to efficient utilization of high-sulfur coals. Tests simulating the environment in the superheater bank of a pulverized-coal-fired boiler were conducted on several promising new alloys and claddings. Alloys were exposed to a variety of synthetic ash and simulated flue gas compositions at 650 and 700{degrees}C for times ranging up to 800 hours. Included in the testing program were new high-chromium/high-nickel alloys, modified commercial alloys, lean stainless steels (modified Type 316) clad with high-chromium/high-nickel alloys, and intermetallic aluminides. Thickness loss measurements indicated that resistance to attach improved with increasing chromium level. Silicon and aluminum were also helpful in resisting attack, while molybdenum was detrimental to the resistance of the alloys to attack. Three different attack modes were observed on the alloys tested. Alloys with low resistance to attack exhibited uniform wastage, while pitting was observed in more resistant alloys. In addition to surface fluxing by molten alkali-iron trisulfates, subsurface sulfur penetration and intergranular attack also occurred.

  17. Fireside corrosion testing of candidate superheater tube alloys, coatings, and claddings

    SciTech Connect

    Van Weele, S. )

    1991-08-01

    Fireside corrosion, caused by liquid alkali-iron trisulfates, has been an obstacle to higher steam temperatures and to efficient utilization of high-sulfur coals. Tests simulating the environment in the superheater bank of a pulverized-coal-fired boiler were conducted on several promising new alloys and claddings. Alloys were exposed to a variety of synthetic ash and simulated flue gas compositions at 650 and 700{degrees}C for times ranging up to 800 hours. Included in the testing program were new high-chromium/high-nickel alloys, modified commercial alloys, lean stainless steels (modified Type 316) clad with high-chromium/high-nickel alloys, and intermetallic aluminides. Thickness loss measurements indicated that resistance to attach improved with increasing chromium level. Silicon and aluminum were also helpful in resisting attack, while molybdenum was detrimental to the resistance of the alloys to attack. Three different attack modes were observed on the alloys tested. Alloys with low resistance to attack exhibited uniform wastage, while pitting was observed in more resistant alloys. In addition to surface fluxing by molten alkali-iron trisulfates, subsurface sulfur penetration and intergranular attack also occurred.

  18. Investigating the Inter-Tube Conduction Mechanism in Polycarbonate Nanocomposites Prepared with Conductive Polymer-Coated Carbon Nanotubes.

    PubMed

    Ventura, Isaac Aguilar; Zhou, Jian; Lubineau, Gilles

    2015-12-01

    A well-known strategy to improve the electrical conductivity of polymers is to dope them with high-aspect-ratio and conductive nanoparticles such as carbon nanotubes (CNTs). However, these nanocomposites also exhibit undesirable properties such as damage-sensitive and history-dependent conductivity because their macroscopic electrical conductivity is largely determined by the tunneling effect at the tube/tube interface. To reduce these issues, new nanocomposites have been developed with CNTs that have been coated with a conductive layer of poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT/PSS). It has been posited that the insulating region between the CNTs is replaced by a conductive polymer bridge; this has not been proven up to now. We propose here to investigate in-depth how the macroscopic conductivity of these materials is changing when (1) varying the frequency of the electrical loading (impedance spectroscopy), (2) varying the mechanical hydrostatic pressure, and (3) varying the voltage of the electrical loading. The response is systematically compared to the one of conventional carbon nanotube/polycarbonate (CNT/PC) nanocomposites so we can clarify how efficiently the tunneling effect is suppressed from these composites. The objective is to elucidate further the mechanism for conduction in such material formulations. PMID:26676996

  19. Investigating the Inter-Tube Conduction Mechanism in Polycarbonate Nanocomposites Prepared with Conductive Polymer-Coated Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Ventura, Isaac Aguilar; Zhou, Jian; Lubineau, Gilles

    2015-12-01

    A well-known strategy to improve the electrical conductivity of polymers is to dope them with high-aspect-ratio and conductive nanoparticles such as carbon nanotubes (CNTs). However, these nanocomposites also exhibit undesirable properties such as damage-sensitive and history-dependent conductivity because their macroscopic electrical conductivity is largely determined by the tunneling effect at the tube/tube interface. To reduce these issues, new nanocomposites have been developed with CNTs that have been coated with a conductive layer of poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT/PSS). It has been posited that the insulating region between the CNTs is replaced by a conductive polymer bridge; this has not been proven up to now. We propose here to investigate in-depth how the macroscopic conductivity of these materials is changing when (1) varying the frequency of the electrical loading (impedance spectroscopy), (2) varying the mechanical hydrostatic pressure, and (3) varying the voltage of the electrical loading. The response is systematically compared to the one of conventional carbon nanotube/polycarbonate (CNT/PC) nanocomposites so we can clarify how efficiently the tunneling effect is suppressed from these composites. The objective is to elucidate further the mechanism for conduction in such material formulations.

  20. The use of ultrasonic testing in determining waterside deposit buildup in boiler systems

    SciTech Connect

    Hicks, P.; Banweg, A.; Parker, M.

    1994-12-31

    A great emphasis is being placed on predictive and preventative maintenance programs as a part of the solution to ensure trouble free boiler operation. This paper describes one such program, an ultrasonic technique used to identify waterside deposit loading in boiler tubes. The technique is designed to differentiate between regions within a boiler that have lower, moderate and higher deposit buildup. The technique thus provides a relative indication of deposit accumulation. This ultrasonic test is ideally suited for outages when routine furnace wall thickness testing is being performed. Tube sampling can be made far more meaningful and a deposit map of the boiler as well as the effectiveness of acid cleaning a boiler can be determined. It would thus become economical to determine the loading profile over large areas of boiler, without sectioning tubes needlessly. Careful consideration needs to be given to the type of boiler tubes examined, surface conditions and deposit characteristics.

  1. 9. RW Meyer Sugar Mill: 18761889. Locomotivetype, firetube, portable boiler, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. RW Meyer Sugar Mill: 1876-1889. Locomotive-type, fire-tube, portable boiler, No. 1 model. Manufactured by Ames Iron Works, Oswego, New York, 1879. 120 lbs/sq. inch working pressure, 66 sq. ft. heating surface in tubes. View: from side. The boiler provided steam for steam engine which in turn powered the mill's centrifugals. The section on the left side included the firebox with its surrounding water-legs. The fluted chimney-type structure is the steam port, safety valve, and whistle. Column projecting from side was part of steam pressure and water gauge. Pipe running above boiler carried steam to the engine. Pipe running below boiler provided the boiler feed-water. Cylindrical section included 22 fire-tube surrounded by water. The far right ... - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

  2. 34. (Credit JTL) Front (north side) of three water tube ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    34. (Credit JTL) Front (north side) of three water tube boilers built by the Heine Safety Boiler Co. of St. Louis, Missouri in 1917; rebuilt in 1938. Front doors opened on center boiler to show water header and inspection plugs for water tubes. Smaller doors beneath open into firebox; boilers presently equipped for gas firing. Operating pressure approx. 150 psi (saturated steam). - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

  3. Partial Obstruction of the Endotracheal Tube by the Plastic Coating Sheared from a Stylet.

    PubMed

    Das, Anirudha; Chagalamarri, Shwetha; Saridakis, Kim

    2016-01-01

    A preterm with gestational age of 24 weeks was intubated at day of life 16. The intubation was done in a routine manner with the use of a stylet. It took a significant effort from the clinician to pull the stylet out after intubation. After intubation the respiratory status of the neonate deteriorated requiring significantly greater support. When ventilating and oxygenating the infant was getting progressively difficult, the decision was made to change the endotracheal tube (ETT). The cause for deterioration of respiratory status was then determined to be a sheared piece of plastic from the sheath of the stylet which was lodged in the lumen of the ETT. After removal of the plastic particle, the condition of the infant improved significantly. PMID:26989545

  4. Fossil-Fired Boilers

    Energy Science and Technology Software Center (ESTSC)

    1993-09-23

    Boiler Performance Model (BPM 3.0S) is a set of computer programs developed to analyze the performance of fossil-fired utility boilers. The programs can model a wide variety of boiler designs, and can model coal, oil, or natural gas firing. The programs are intended for use by engineers performing analyses of alternative fuels, alternative operating modes, or boiler modifications.

  5. 32. INTERIOR BOILER HOUSE Above the two furnaces, one ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. INTERIOR - BOILER HOUSE Above the two furnaces, one of the boilers can be seen to the upper left. The large pipes in the foreground are all that remain of the distribution system. Most of the pipe and tubing have been stripped from the room and sold for scrap. - Hovden Cannery, 886 Cannery Row, Monterey, Monterey County, CA

  6. 34. TOP O THE BOILER SHOWING CONSTRUCTION DETAILS. NOTE THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    34. TOP O THE BOILER SHOWING CONSTRUCTION DETAILS. NOTE THE 1/2-INCH ROUND IRON REINFORCING ROD AND GALVANIZED FARM FENCING IN THE RIGHT FOREGROUND. AND THE EXPANDED METAL LATH WITH CEMENT COATING IN THE CEILING ABOVE THE BOILER. - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

  7. Cermet composite thermal spray coatings for erosion and corrosion protection in combustion environments of advanced coal-fired boilers. Semiannual technical progress report, August 14, 1996--January 14, 1997

    SciTech Connect

    Levin, B.F.; DuPont, J.N.; Marder, A.R.

    1997-02-01

    Research is presently being conducted to determine the optimum ceramic/metal combination in thermally sprayed metal matrix composite coatings for erosion and corrosion resistance in new coal-fired boilers. The research will be accomplished by producing model cermet composites using powder metallurgy and electrodeposition methods in which the effect of ceramic/metal combination for the erosion and corrosion resistance will be determined. These results will provide the basis for determining the optimum hard phase constituent size and volume percent in thermal spray coatings. Thermal spray coatings will be applied by our industrial sponsor and tested in our erosion and corrosion laboratories. In the first six months of this project, bulk powder processed Ni-Al{sub 2}O{sub 3} composites were produced at Idaho National Engineering Laboratory. The results of microstructural characterization of these alloys were presented in the first semiannual report. The composite samples contained 0, 21, 27, 37, and 45 volume percent Al{sub 2}O{sub 3} with an average particle size of 12 um. An increase in the volume fraction of alumina in the nickel matrix from 0 to 45% led to a significant increase in hardness of these composites.

  8. Coatings.

    ERIC Educational Resources Information Center

    Anderson, Dennis G.

    1989-01-01

    This review covers analytical techniques applicable to the examination of coatings, raw materials, and substrates upon which coatings are placed. Techniques include chemical and electrochemical methods, chromatography, spectroscopy, thermal analysis, microscopy, and miscellaneous techniques. (MVL)

  9. A Rule-Based Industrial Boiler Selection System

    NASA Astrophysics Data System (ADS)

    Tan, C. F.; Khalil, S. N.; Karjanto, J.; Tee, B. T.; Wahidin, L. S.; Chen, W.; Rauterberg, G. W. M.; Sivarao, S.; Lim, T. L.

    2015-09-01

    Boiler is a device used for generating the steam for power generation, process use or heating, and hot water for heating purposes. Steam boiler consists of the containing vessel and convection heating surfaces only, whereas a steam generator covers the whole unit, encompassing water wall tubes, super heaters, air heaters and economizers. The selection of the boiler is very important to the industry for conducting the operation system successfully. The selection criteria are based on rule based expert system and multi-criteria weighted average method. The developed system consists of Knowledge Acquisition Module, Boiler Selection Module, User Interface Module and Help Module. The system capable of selecting the suitable boiler based on criteria weighted. The main benefits from using the system is to reduce the complexity in the decision making for selecting the most appropriate boiler to palm oil process plant.

  10. Factors affecting stress assisted corrosion cracking of carbon steel under industrial boiler conditions

    NASA Astrophysics Data System (ADS)

    Yang, Dong

    Failure of carbon steel boiler tubes from waterside has been reported in the utility boilers and industrial boilers for a long time. In industrial boilers, most waterside tube cracks are found near heavy attachment welds on the outer surface and are typically blunt, with multiple bulbous features indicating a discontinuous growth. These types of tube failures are typically referred to as stress assisted corrosion (SAC). For recovery boilers in the pulp and paper industry, these failures are particularly important as any water leak inside the furnace can potentially lead to smelt-water explosion. Metal properties, environmental variables, and stress conditions are the major factors influencing SAC crack initation and propagation in carbon steel boiler tubes. Slow strain rate tests (SSRT) were conducted under boiler water conditions to study the effect of temperature, oxygen level, and stress conditions on crack initation and propagation on SA-210 carbon steel samples machined out of boiler tubes. Heat treatments were also performed to develop various grain size and carbon content on carbon steel samples, and SSRTs were conducted on these samples to examine the effect of microstructure features on SAC cracking. Mechanisms of SAC crack initation and propagation were proposed and validated based on interrupted slow strain tests (ISSRT). Water chemistry guidelines are provided to prevent SAC and fracture mechanics model is developed to predict SAC failure on industrial boiler tubes.

  11. Comparison of two dose-area-product ionization chambers with different conductive surface coating for over-table and under-table tube configurations

    SciTech Connect

    Bednarek, D.R.; Rudin, S.

    2000-03-01

    A custom-built graphite-coated transmission ionization chamber is compared to the VacuDAP 2001 (VacuTec, Dresden, Germany), which has transparent conductive electrodes. A study was made of the dependence of response on x-ray tube potential for both types of chamber under identical conditions of exposure using over-table and under-table x-ray tubes. Since the calibration factor is the dose-area product of the radiation incident on the patient per chamber reading, it depends on the intrinsic response of the chamber as well as the effect of material in the beam between the x-ray tube and patient. Differences of about 20% were measured between the intrinsic and the over-table calibration factors and between the over-table and the under-table calibration factors for both chambers. The VacuDAP display is specifically calibrated for the over-table condition and would overstate the actual DAP in the under-table case. The intrinsic response of the graphite chamber is nearly independent of tube potential. Although the variation of response with tube potential of the graphite chamber is increased when it is used as an over-table and an under-table patient monitor, it shows less overall variation of response than the VacuDAP. The average deviation of each range of 40 to 140 kVp for both chambers.

  12. 46 CFR 52.15-5 - Tube connections (modifies PWT-9 and PWT-11).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... of section I of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 52.01... 46 Shipping 2 2010-10-01 2010-10-01 false Tube connections (modifies PWT-9 and PWT-11). 52.15-5... BOILERS Requirements for Watertube Boilers § 52.15-5 Tube connections (modifies PWT-9 and PWT-11)....

  13. 46 CFR 52.15-5 - Tube connections (modifies PWT-9 and PWT-11).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... of section I of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 52.01... 46 Shipping 2 2014-10-01 2014-10-01 false Tube connections (modifies PWT-9 and PWT-11). 52.15-5... BOILERS Requirements for Watertube Boilers § 52.15-5 Tube connections (modifies PWT-9 and PWT-11)....

  14. 46 CFR 52.15-5 - Tube connections (modifies PWT-9 and PWT-11).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... of section I of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 52.01... 46 Shipping 2 2011-10-01 2011-10-01 false Tube connections (modifies PWT-9 and PWT-11). 52.15-5... BOILERS Requirements for Watertube Boilers § 52.15-5 Tube connections (modifies PWT-9 and PWT-11)....

  15. Resistance of Nanostructured Environmental Barrier Coatings to the Movement of Molten Salts

    NASA Astrophysics Data System (ADS)

    Rao, S.; Frederick, L.; McDonald, A.

    2012-09-01

    Corrosion of components in a recovery boiler is a major problem faced by the pulp and paper industry. The superheater tubes become severely corroded due to the presence of sulfidic gases in the boiler and molten salts which are deposited on the surface of the tubes. As a result, the boiler must be decommissioned for expensive maintenance and repairs. Yttria-stabilized zirconia (YSZ) coatings have been shown to provide corrosion resistance when applied on gas turbines operating at high temperatures. Air plasma-sprayed YSZ environmental barrier coatings on Type 309 stainless steel were exposed to three different corrosive environments: Test A—600 °C, salt vapors, flue gases, 168 h; Test B—600 °C, molten salt, air, 168 h; and Test C—600 °C, molten salt, flue gases, 168 h. Two different types of YSZ coatings—conventional YSZ and nanostructured YSZ—were tested to study their resistance to corrosion and molten salt penetration. The performances of both types of coatings were evaluated, and a comparative study was conducted. It was found that the nanostructured YSZ samples protected the stainless steel substrate better than their conventional counterparts. This superior performance was attributed to the presence of semi-molten nano-agglomerates present in the coating microstructure, which acted as collection points for the penetrating molten salts.

  16. Evaluation of a coated-tube assay for antithyrotropin receptor antibodies in patients with Graves' disease and other thyroid disorders.

    PubMed

    Cardia, Maria Silvia; Lima, Nicolau; Knobel, Meyer; Medeiros-Neto, Geraldo

    2004-04-01

    The detection of autoantibodies to the thyrotropin-receptor antibody (TRAb) is commonly used in clinical practice for the diagnostic assessment of Graves' disease (GD) and its differential diagnosis from toxic multinodular goiter (MNG) and autonomous adenoma. Additionally, TRAb assays can be useful during antithyroid drug treatment of GD to evaluate the risk of relapse and/or remission. The detection of TRAb was originally performed using a radioreceptor assay based on detergent-solubilized porcine thyroid membranes (TRAb). More recently new assays using purified porcine or recombinant human thyrotropin (TSH) receptor-coated plastic tubes (CT) have been developed (pCT-TRAb or hCT-TRAb). We have evaluated both assays (TRAb and pCTTRAb) in 300 individuals: healthy controls (n = 51); patients with GD before and after treatment (n = 200), patients with MNG (n = 29), and Hashimoto's thyroiditis [HT; n = 20]). All healthy controls and patients with HT had undetectable TRAb using both methods. Patients with active (not treated) GD had higher pCT-TRAb values (mean +/- standard deviation [SD], 58.2% +/- 20.3%, inhibition of TSH binding) compared to TRAb (41.2% +/- 15.4%, p < 0.01, Wilcoxon test). Results (as percent inhibition for both methods) had a positive and significant correlation (r = 0.68, p < 0.001). Moreover TRAb assay had a 97.3% sensitivity and 96.8% specificity; the pCT-TRAb sensitivity was 96.3% and specificity was 98.4% at a cutoff of 1.51 U/L. During treatment of GD, the TRAb method resulted in significantly lower (p < 0.05) values at 12, 24, and 30 months, while pCT-TRAb only exhibited significancy (compared to basal levels) at 30 months. The percent inhibition after 131I treatment of GD was significantly higher for pCT-TRAb (33.7 +/- 25.7) compared to TRAb (21.9 +/- 17.7, p < 0.01, Wilcoxon test). Only one patient with untreated MNG had a positive pCT-TRAb but negative TRAb value. Patients with MNG treated with 131I were divided into two groups: group 1

  17. BOILER PERF MODEL

    SciTech Connect

    Winslow, J.C. )

    1988-01-01

    The BOILER PERFORMANCE MODEL is a package of eleven programs for predicting the heat transfer performance of fossil-fired utility boilers. The programs can model a wide variety of boiler designs, provide boiler performance estimates for coal, oil or gaseous fuels, determine the influence of slagging and fouling characteristics on boiler performance, and calculate performance factors for tradeoff analyses comparing boilers and fuels. Given a set of target operating conditions, the programs can estimate control settings, gas and steam operating profiles through the boiler, overall boiler efficiency, and fuel consumption. The programs are broken into three categories: data, calculation, and reports with a central processor program acting as the link allowing the user to access any of the data or calculation programs and easily move between programs. The calculations are divided among the following five programs: heat duty calculation, combustion calculation, furnace performance calculation, convection pass performance calculation, and air heater performance calculation. The programs can model subcritical or supercritical boilers, most configurations of convective passes including boilers that achieve final reheat steam temperature control by split back pass, boilers with as many as two reheat circuits and/or multiple attemperator stations in series, and boilers with or without economizers and/or air heaters. Either regenerative or tubular air heaters are supported. For wall-fired or tangentially-fired furnaces, the furnace performance program predicts the temperature of the flue gases leaving the furnace. It accounts for variations in excess air, gas recirculation, burner tilt, wall temperature, and wall cleanliness. For boilers having radiant panels or platens above the furnace, the convective pass program uses the results of the combustion chamber calculation to estimate the gas temperature entering the convective pass.

  18. 33. BOILER HOUSE FURNACE AND BOILER Close view of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. BOILER HOUSE - FURNACE AND BOILER Close view of the Dorward Engineering Company furnace and boiler which provided steam to the cooking retorts in the adjacent room. - Hovden Cannery, 886 Cannery Row, Monterey, Monterey County, CA

  19. 51. BOILER ROOM. SMALL BOILER ON LEFT OF UNKNOWN MANUFACTURE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    51. BOILER ROOM. SMALL BOILER ON LEFT OF UNKNOWN MANUFACTURE, WITH INDUCTION MOTORS. HARTLEY BOILER, MONTGOMERY, ALABAMA, ON RIGHT. - Prattville Manufacturing Company, Number One, 242 South Court Street, Prattville, Autauga County, AL

  20. Boiler saves pollution problem

    SciTech Connect

    Kaiser, J.A.

    1981-02-01

    Monarch Furniture Industries, High Point, N.C. replaced their old locomotive-type boiler in 1978 with a multifuel boiler system from Energy Systems, Inc. of Chattanooga. The system burns the company's wood wastes, supplemented with low-cost coal in winter. It generates 17,250 lbs. per hour of steam, gives a much cleaner burn than the old boiler, and has a calculated payback period of 1.67 years.

  1. 17. Internal view of boiler in steam space above return ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. Internal view of boiler in steam space above return flues. View looks forward in ship toward fireboxes; tubes (flues) below carry hot combustion gases from return chamber to smoke chamber. From thence gasses flow through vertical pipe at left into steam stack, and eventually to ship's smokestack. Inclined and radiating straps are stays used to reinforce boiler plates against distortion under pressure. - Ferry TICONDEROGA, Route 7, Shelburne, Chittenden County, VT

  2. Oxide Dispersion Strengthened Iron Aluminide by CVD Coated Powders

    SciTech Connect

    Asit Biswas Andrew J. Sherman

    2006-09-25

    This I &I Category2 program developed chemical vapor deposition (CVD) of iron, aluminum and aluminum oxide coated iron powders and the availability of high temperature oxidation, corrosion and erosion resistant coating for future power generation equipment and can be used for retrofitting existing fossil-fired power plant equipment. This coating will provide enhanced life and performance of Coal-Fired Boilers components such as fire side corrosion on the outer diameter (OD) of the water wall and superheater tubing as well as on the inner diameter (ID) and OD of larger diameter headers. The program also developed a manufacturing route for readily available thermal spray powders for iron aluminide coating and fabrication of net shape component by powder metallurgy route using this CVD coated powders. This coating can also be applid on jet engine compressor blade and housing, industrial heat treating furnace fixtures, magnetic electronic parts, heating element, piping and tubing for fossil energy application and automotive application, chemical processing equipment , heat exchanger, and structural member of aircraft. The program also resulted in developing a new fabrication route of thermal spray coating and oxide dispersion strengthened (ODS) iron aluminide composites enabling more precise control over material microstructures.

  3. Production of Nanocrystalline Ni-20Cr Coatings for High-Temperature Applications

    NASA Astrophysics Data System (ADS)

    Kumar, Manoj; Singh, Harpreet; Singh, Narinder

    2014-04-01

    Presynthesized nanocrystalline Ni-20Cr powder was deposited on SA 516 and T91 boiler steels by a high-velocity oxy-fuel spraying process. Ni-20Cr powder was synthesized by the ball milling approach. The high-temperature oxidation behavior of bare and coated samples was then studied under cyclic isothermal conditions at 900 °C for 50 cycles. The kinetics of oxidation was established using weight change measurements for the bare and coated boiler steels. Uncoated and coated samples of T91 steel were exposed to the superheated zone of a power plant boiler at 750 °C under cyclic conditions for 15 cycles. Each cycle consisted of 100 h of heating followed by 1 h of cooling. Attempts were made to study the kinetics of erosion-corrosion using weight change and thickness loss data for the samples. Different characterization techniques were used to study the oxidized and eroded-corroded samples, including x-ray diffraction, scanning electron microscopy/energy-dispersive spectroscopy, and x-ray mapping analyses. The Ni-20Cr alloy powder coating was found to offer excellent oxidation resistance to the base steels and was successful in reducing the weight gain of SA 516 steel by 98.5 % and that of T91 steel by 65 %. The coating was observed to reduce the erosion-corrosion rate of T91 steel by 86 % in terms of thickness loss. This indicates that the investigated nanostructured coating can be a better choice over conventional coating for erosion-corrosion control of boiler tubes.

  4. Improved Process control of wood waste fired boilers

    SciTech Connect

    Process Control Solutions, Inc.

    2004-01-30

    This project's principal aim was the conceptual and feasibility stage development of improved process control methods for wood-waste-fired water-tube boilers operating in industrial manufacturing applications (primarily pulp and paper). The specific objectives put forth in the original project proposal were as follows: (1) fully characterize the wood-waste boiler control inter-relationships and constraints through data collection and analysis; (2) design an improved control architecture; (3) develop and test an appropriate control and optimization algorithm; and (4) develop and test a procedure for reproducing the approach and deriving the benefits on similar pulp and paper wood-waste boilers. Detailed tasks were developed supporting these objectives.

  5. Super Boiler: Packed Media/Transport Membrane Boiler Development and Demonstration

    SciTech Connect

    Liss, William E; Cygan, David F

    2013-04-17

    Gas Technology Institute (GTI) and Cleaver-Brooks developed a new gas-fired steam generation system the Super Boiler for increased energy efficiency, reduced equipment size, and reduced emissions. The system consists of a firetube boiler with a unique staged furnace design, a two-stage burner system with engineered internal recirculation and inter-stage cooling integral to the boiler, unique convective pass design with extended internal surfaces for enhanced heat transfer, and a novel integrated heat recovery system to extract maximum energy from the flue gas. With these combined innovations, the Super Boiler technical goals were set at 94% HHV fuel efficiency, operation on natural gas with <5 ppmv NOx (referenced to 3%O2), and 50% smaller than conventional boilers of similar steam output. To demonstrate these technical goals, the project culminated in the industrial demonstration of this new high-efficiency technology on a 300 HP boiler at Clement Pappas, a juice bottler located in Ontario, California. The Super Boiler combustion system is based on two stage combustion which combines air staging, internal flue gas recirculation, inter-stage cooling, and unique fuel-air mixing technology to achieve low emissions rather than external flue gas recirculation which is most commonly used today. The two-stage combustion provides lower emissions because of the integrated design of the boiler and combustion system which permit precise control of peak flame temperatures in both primary and secondary stages of combustion. To reduce equipment size, the Super Boiler's dual furnace design increases radiant heat transfer to the furnace walls, allowing shorter overall furnace length, and also employs convective tubes with extended surfaces that increase heat transfer by up to 18-fold compared to conventional bare tubes. In this way, a two-pass boiler can achieve the same efficiency as a traditional three or four-pass firetube boiler design. The Super Boiler is consequently up to

  6. Compartment B3, boiler room; showing boiler facing of boiler #5 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Compartment B-3, boiler room; showing boiler facing of boiler #5 aft to forward from passing room B-25. (030A) - USS Olympia, Penn's Landing, 211 South Columbus Boulevard, Philadelphia, Philadelphia County, PA

  7. Improving boiler efficiency

    SciTech Connect

    Yost, L.

    1982-06-24

    Boilers and burners are designed to operate most efficiently at, or near, full load. This fact seems to indicate that on/off operation is more efficient; however, standby losses must be considered. This article examines various types of industrial boiler heat losses that reduce efficiency and discusses methods for improving operation.

  8. 39. (Credit JTL) Interior of boiler room looking east; boiler ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    39. (Credit JTL) Interior of boiler room looking east; boiler casing in background, boiler feedwater pumps and feedwater heater in middle ground; hot well on columns in left foreground. Steam lines from boilers to high service engines pass overhead. - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

  9. 68. 1911 BOILER HOUSE LOOKING SOUTH. BOILERS ARE CA. 1945. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    68. 1911 BOILER HOUSE LOOKING SOUTH. BOILERS ARE CA. 1945. SPACE HEATING BOILER S REPLACED ORIGINAL 8 VERTICAL HIGH PRESSURE STEAM POWER BOILERS. THE ORIGINAL SHEET METAL FLUE IS IN THE UPPER CENTER. - Boston Manufacturing Company, 144-190 Moody Street, Waltham, Middlesex County, MA

  10. Preparing hydroxyapatite-silicon composite suspensions with homogeneous distribution of multi-walled carbon nano-tubes for electrophoretic coating of NiTi bone implant and their effect on the surface morphology

    NASA Astrophysics Data System (ADS)

    Khalili, Vida; Khalil-Allafi, Jafar; Xia, Wei; Parsa, Alireza B.; Frenzel, Jan; Somsen, Christoph; Eggeler, Gunther

    2016-03-01

    Preparing a stable suspension is a main step towards the electrophoretically depositing of homogeneous and dense composite coatings on NiTi for its biomedical application. In the present study, different composite suspensions of hydroxyapatite, silicon and multi-walled carbon nano-tubes were prepared using n-butanol and triethanolamine as media and dispersing agent, respectively. Multi-walled carbon nanotubes were first functionalized in the nitric acid vapor for 15 h at 175 °C, and then mixed into suspensions. Thermal desorption spectroscopy profiles indicate the formation of functional groups on multi-walled carbon nano-tubes. An excellent suspension stability can be achieved for different amounts of triethanolamine. The amount of triethanolamine can be increased by adding a second component to a stable hydroxyapatite suspension due to an electrostatic interaction between components in suspension. The stability of composite suspension is less than that of the hydroxyapatite suspension, due to density differences, which under the gravitational force promote the demixing. The scanning electron microscopy images of the coatings surface show that more dense coatings are developed on NiTi substrate using electrophoretic deposition and sintering at 850 °C in the simultaneous presence of silicon and multi-walled carbon nanotubes in the hydroxyapatite coatings. The atomic force microscopy results of the coatings surface represent that composite coatings of hydroxyapatite-20 wt.% silicon and hydroxyapatite-20 wt.% silicon-1 wt.% multi-walled carbon nano-tubes with low zeta potential have rougher surfaces.

  11. Robotic weld overlay coatings for erosion control

    SciTech Connect

    Not Available

    1994-11-01

    The erosion of materials by the impact of solid particles has received increasing attention during the past twenty years. Recently, research has been initiated with the event of advanced coal conversion processes in which erosion plays an important role. The resulting damage, termed Solid Particle Erosion (SPE), is of concern primarily because of the significantly increased operating costs which result in material failures. Reduced power plant efficiency due to solid particle erosion of boiler tubes and waterfalls has led to various methods to combat SPE. One method is to apply coatings to the components subjected to erosive environments. Protective weld overlay coatings are particularly advantageous in terms of coating quality. The weld overlay coatings are essentially immune to spallation due to a strong metallurgical bond with the substrate material. By using powder mixtures, multiple alloys can be mixed in order to achieve the best performance in an erosive environment. However, a review of the literature revealed a lack of information on weld overlay coating performance in erosive environments which makes the selection of weld overlay alloys a difficult task. The objective of this project is to determine the effects of weld overlay coating composition and microstructure on erosion resistance. These results will lead to a better understanding of erosion mitigation in CFB`s.

  12. Robotic weld overlay coatings for erosion control

    NASA Astrophysics Data System (ADS)

    The erosion of materials by the impact of solid particles has received increasing attention during the past twenty years. Recently, research has been initiated with the event of advanced coal conversion processes in which erosion plays an important role. The resulting damage, termed Solid Particle Erosion (SPE), is of concern primarily because of the significantly increased operating costs which result in material failures. Reduced power plant efficiency due to solid particle erosion of boiler tubes and waterfalls has led to various methods to combat SPE. One method is to apply coatings to the components subjected to erosive environments. Protective weld overlay coatings are particularly advantageous in terms of coating quality. The weld overlay coatings are essentially immune to spallation due to a strong metallurgical bond with the substrate material. By using powder mixtures, multiple alloys can be mixed in order to achieve the best performance in an erosive environment. However, a review of the literature revealed a lack of information on weld overlay coating performance in erosive environments which makes the selection of weld overlay alloys a difficult task. The objective of this project is to determine the effects of weld overlay coating composition and microstructure on erosion resistance. These results will lead to a better understanding of erosion mitigation in CFB's.

  13. Clean Firetube Boiler Waterside Heat Transfer Surfaces, Energy Tips: STEAM, Steam Tip Sheet #7 (Fact Sheet)

    SciTech Connect

    Not Available

    2012-04-01

    A steam energy tip sheet for the Advanced Manufacturing Office (AMO). The prevention of scale formation in firetube boilers can result in substantial energy savings. Scale deposits occur when calcium, magnesium, and silica, commonly found in most water supplies, react to form a continuous layer of material on the waterside of the boiler heat exchange tubes. Scale creates a problem because it typically possesses a thermal conductivity, an order of magnitude less than the corresponding value for bare steel. Even thin layers of scale serve as an effective insulator and retard heat transfer. The result is overheating of boiler tube metal, tube failures, and loss of energy efficiency. Fuel consumption may increase by up to 5% in firetube boilers because of scale. The boilers steam production may be reduced if the firing rate cannot be increased to compensate for the decrease in combustion efficiency. Energy losses as a function of scale thickness and composition are given. Any scale in a boiler is undesirable. The best way to deal with scale is not to let it form in the first place. Prevent scale formation by: (1) Pretreating of boiler makeup water (using water softeners, demineralizers, and reverse osmosis to remove scale-forming minerals); (2) Injecting chemicals into the boiler feedwater; and (3) Adopting proper boiler blowdown practices.

  14. Drying Milk With Boiler Exhaust

    NASA Technical Reports Server (NTRS)

    Broussard, M. R.

    1984-01-01

    Considerable energy saved in powdered-milk industry. Only special requirement boiler fired with natural gas or other clean fuel. Boiler flue gas fed to spray drier where it directly contacts product to be dried. Additional heat supplied by auxillary combustor when boiler output is low. Approach adaptable to existing plants with minimal investment because most already equipped with natural-gas-fired boilers.

  15. Millwright Apprenticeship. Related Training Modules. 7.1-7.9 Boilers.

    ERIC Educational Resources Information Center

    Lane Community Coll., Eugene, OR.

    This packet, part of the instructional materials for the Oregon apprenticeship program for millwright training, contains nine modules covering boilers. The modules provide information on the following topics: fire and water tube types of boilers, construction, fittings, operation, cleaning, heat recovery systems, instruments and controls, and…

  16. Non-cytotoxic silver nanoparticle-polyvinyl alcohol hydrogels with anti-biofilm activity: designed as coatings for endotracheal tube materials.

    PubMed

    Loo, Ching-Yee; Young, Paul M; Lee, Wing-Hin; Cavaliere, Rosalia; Whitchurch, Cynthia B; Rohanizadeh, Ramin

    2014-01-01

    Endotracheal intubation is commonly associated with hospital-acquired infections as the intubation device acts as reservoir for bacterial colonization in the lungs. To reduce the incidence of bacterial colonization on the tubes, hydrogel coatings loaded with antimicrobial agents are gaining popularity. The aim of this study was to incorporate silver nanoparticles (AgNPs) into polyvinyl alcohol (PVA) to form stable hydrogels. Embedding AgNPs into PVA resulted in a decreased elongation at break and an increased tensile strength compared to PVA alone. The Ag release profile varied as a function of the degree of hydrolysis of PVA: the higher degree of hydrolysis demonstrated a lower release rate. Fourier infrared transform spectroscopy demonstrated that AgNPs interacted exclusively with the -OH groups of PVA. AgNP-loaded PVA was non-toxic against human normal bronchial epithelial cells while effective against the attachment of Pseudomonas aeruginosa and Staphylococcus aureus with a greater effect on P. aeruginosa. PMID:24963686

  17. Materials for the pulp and paper industry. Section 1: Development of materials for black liquor recovery boilers

    SciTech Connect

    Keiser, J.R.; Hubbard, C.R.; Payzant, E.A.

    1997-04-01

    Black liquor recovery boilers are essential components of kraft pulp and paper mills because they are a critical element of the system used to recover the pulping chemicals required in the kraft pulping process. In addition, the steam produced in these boilers is used to generate a significant portion of the electrical power used in the mill. Recovery boilers require the largest capital investment of any individual component of a paper mill, and these boilers are a major source of material problems in a mill. The walls and floors of these boilers are constructed of tube panels that circulate high pressure water. Molten salts (smelt) accumulate on the floor of recovery boilers, and leakage of water into the boiler can result in a violent explosion when the leaked water instantly vaporizes upon contacting the molten smelt. Because corrosion of the conventionally-used carbon steel tubing was found to be excessive in the lower section of recovery boilers, use of stainless steel/carbon steel co-extruded tubing was adopted for boiler walls to lessen corrosion and reduce the likelihood of smelt/water explosions. Eventually, this co-extruded or composite (as it is known in the industry) tubing was selected for use as a portion or all of the floor of recovery boilers, particularly those operating at pressures > 6.2 MPa (900 psi), because of the corrosion problems encountered in carbon steel floor tubes. Since neither the cause of the cracking nor an effective solution has been identified, this program was established to develop a thorough understanding of the degradation that occurs in the composite tubing used for walls and floors. This is being accomplished through a program that includes collection and review of technical reports, examination of unexposed and cracked tubes from boiler floors, computer modeling to predict residual stresses under operating conditions, and operation of laboratory tests to study corrosion, stress corrosion cracking, and thermal fatigue.

  18. Lead determination at ng/mL level by flame atomic absorption spectrometry using a tantalum coated slotted quartz tube atom trap.

    PubMed

    Demirtaş, İlknur; Bakırdere, Sezgin; Ataman, O Yavuz

    2015-06-01

    Flame atomic absorption spectrometry (FAAS) still keeps its importance despite the relatively low sensitivity; because it is a simple and economical technique for determination of metals. In recent years, atom traps have been developed to increase the sensitivity of FAAS. Although the detection limit of FAAS is only at the level of µg/mL, with the use of atom traps it can reach to ng/mL. Slotted quartz tube (SQT) is one of the atom traps used to improve sensitivity. In atom trapping mode of SQT, analyte is trapped on-line in SQT for few minutes using ordinary sample aspiration, followed by the introduction of a small volume of organic solvent to effect the revolatilization and atomization of analyte species resulting in a transient signal. This system is economical, commercially available and easy to use. In this study, a sensitive analytical method was developed for the determination of lead with the help of SQT atom trapping flame atomization (SQT-AT-FAAS). 574 Fold sensitivity enhancement was obtained at a sample suction rate of 3.9 mL/min for 5.0 min trapping period with respect to FAAS. Organic solvent was selected as 40 µL of methyl isobutyl ketone (MIBK). To obtain a further sensitivity enhancement inner surface of SQT was coated with several transition metals. The best sensitivity enhancement, 1650 fold enhancement, was obtained by the Ta-coated SQT-AT-FAAS. In addition, chemical nature of Pb species trapped on quartz and Ta surface, and the chemical nature of Ta on quartz surface were investigated by X-ray photoelectron spectroscopy (XPS) and Raman Spectroscopy. Raman spectrometric results indicate that tantalum is coated on SQT surface in the form of Ta2O5. XPS studies revealed that the oxidation state of Pb in species trapped on both bare and Ta coated SQT surfaces is +2. For the accuracy check, the analyses of standard reference material were performed by use of SCP SCIENCE EnviroMAT Low (EU-L-2) and results for Pb were to be in good agreement with

  19. 46 CFR 59.10-20 - Patches in shells and tube sheets.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Boilers and Pressure Vessels in -Service... boilers or pressure vessels, the diameter of which does not exceed the maximum diameter of an unreinforced... vessels are met. (b) Portions of tube sheets which have deteriorated may be renewed by replacing...

  20. 46 CFR 59.10-20 - Patches in shells and tube sheets.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Boilers and Pressure Vessels in -Service... boilers or pressure vessels, the diameter of which does not exceed the maximum diameter of an unreinforced... vessels are met. (b) Portions of tube sheets which have deteriorated may be renewed by replacing...

  1. 46 CFR 52.05-45 - Circumferential joints in pipes, tubes and headers (modifies PW-41).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., tubes and headers shall be as required by PW-41 of section I of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 52.01-1) except as noted otherwise in this section. (b) (Modifies PW-41.1...) MARINE ENGINEERING POWER BOILERS Requirements for Boilers Fabricated by Welding §...

  2. Recent experience in condition assessment of boiler header components and supports

    SciTech Connect

    King, J.P.

    1996-12-01

    This paper provides recent experience in the condition assessment of boiler header components and supports in fossil fired power plants. Condition assessment programs for boiler headers are now scheduled more frequently due to the current practices of cyclic operation and extended life for older boilers. Typical assessment tasks as applicable to all boiler headers, are described herein. Examples of common problems, with recommended actions, for each type of header are presented. This includes internal bore hole and ligament cracking, and external tube connector weld cracking. Emphasis will be focused on the historical cracking problems associated with economizer inlet and secondary superheater/reheater outlet headers.

  3. Erosion resistance of cooled thermal sprayed coatings under simulated erosion conditions at waterwall in FBCs

    SciTech Connect

    Wang, B.Q.; Lee, S.W.

    1997-12-31

    The erosion-corrosion (E-C) behavior of cooled 1018 steel and several thermal sprayed coatings by bed ash, retrieved from an operating circulating fluidized bed combustor (CFBC) boiler firing biomass, was determined in laboratory tests using a nozzle type elevated temperature erosion tester. Test conditions attempted but not exactly to simulate the erosion conditions found at the refractory/bare-tube interface at the combustor waterwall of FBC boilers. The specimens were water-cooled on the backside. Material wastage rates were determined from the thickness loss measurements of specimens. Test results were compared with erosion-corrosion test results for isothermal specimens. The morphology of specimens was examined by scanning electron microscopy (SEM). It was found that the cooled specimens demonstrated higher erosion-corrosion wastage than those of the isothermal specimens. At a shallow impact angle of 30{degree} the effect of cooling specimens on the erosion wastage for thermal sprayed coatings was less than that for 1018 steel, while at a steep impact angle of 90{degree} this effect for thermal sprayed coatings was greater than that for 1018 steel. The hypersonic velocity oxygen fuel (HVOF) Cr{sub 3}C{sub 2} ceramic coating exhibited the highest E-C resistance due to its favorable composition and fine structure. The poor E-C resistance of arc-sprayed FeCrSiB coating was attributed to larger splat size, higher porosity and the presence of radial and tangential microcracks within the coating.

  4. In-bed tube bank for a fluidized-bed combustor

    DOEpatents

    Hemenway, Jr., Lloyd F.

    1990-01-01

    An in-bed tube bank (10) for a fluidized bed combustor. The tube bank (10) of the present invention comprises one or more fluid communicating boiler tubes (30) which define a plurality of selectively spaced boiler tube sections (32). The tube sections (32) are substantially parallel to one another and aligned in a common plane. The tube bank (10) further comprises support members (34) for joining adjacent tube sections (32), the support members (34) engaging and extending along a selected length of the tube sections (32) and spanning the preselected space therebetween.

  5. Study of the HVOF Ni-Based Coatings' Corrosion Resistance Applied on Municipal Solid-Waste Incinerators

    NASA Astrophysics Data System (ADS)

    Guilemany, J. M.; Torrell, M.; Miguel, J. R.

    2008-06-01

    Oxidation of exchanger steel tubes causes important problems in Municipal Solid-Waste Incinerator (MSWI) plants. The present paper shows a possible solution for this problem through High-Velocity Oxygen Fuel (HVOF) thermal spray coatings. A comparative study was carried out between powder and wire Ni-based thermal spray coatings (with the same composition). These optimized coatings were compared based on their microstructure, wear properties (ASTM G99-90, ASTM G65-91), and erosion-corrosion (E-C) resistance. An E-C test designed in the Thermal Spray Centre was performed to reproduce the mechanisms that take place in a boiler. Studying the results of this test, the wire HVT Inconel coating sprayed by propylene appears to be the best alternative. A commercial bulk material with a composition similar to Ni-based coatings was tested to find the products of the oxidation reactions. The protective mechanisms of these materials were assessed after studying the results obtained for HVOF coatings and the bulk material where the presence of nickel and chromium oxides as a corrosion product can be seen. Kinetic evolution of the Ni-based coatings can be studied by thermogravimetric analysis. The protection that Inconel coatings give to the tube through the difference of the gain mass can be seen. Ni-based HVOF coatings by both spray conditions are a promising alternative to MSWI protection against chlorine environments, and their structures have a very important role.

  6. DETAIL OF BOILER, SHOWING (TOP TO BOTTOM) ENDS OF STEAM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF BOILER, SHOWING (TOP TO BOTTOM) ENDS OF STEAM CHAMBERS, DOORS GIVING ACCESS TO TUBING, AND SIX BURNERS, CAMERA FACING WEST. - New Haven Rail Yard, Central Steam Plant and Oil Storage, Vicinity of Union Avenue, New Haven, New Haven County, CT

  7. Integrated boiler, superheater, and decomposer for sulfuric acid decomposition

    SciTech Connect

    Moore, Robert; Pickard, Paul S.; Parma, Jr., Edward J.; Vernon, Milton E.; Gelbard, Fred; Lenard, Roger X.

    2010-01-12

    A method and apparatus, constructed of ceramics and other corrosion resistant materials, for decomposing sulfuric acid into sulfur dioxide, oxygen and water using an integrated boiler, superheater, and decomposer unit comprising a bayonet-type, dual-tube, counter-flow heat exchanger with a catalytic insert and a central baffle to increase recuperation efficiency.

  8. Properties and microstructure of the Ru-coated carbon nano tube counter electrode for dye-sensitized solar cells.

    PubMed

    Han, Jeungjo; Yu, Byungkwan; Noh, Yunyoung; Suh, Young Joon; Kim, Moon J; Yoo, Kicheon; Ko, Min Jae; Song, Ohsung

    2014-08-01

    In this study, we investigated the performance of dye-sensitized solar cells (DSSCs) with the ruthenium (Ru) coated multi-walled carbon nanotube (MWCNT) on the counter electrode (CE). High purity MWCNT (0.01~0.06 g) was sprayed on glass/fluorine-doped tin oxide (FTO). Then 30 nm-thick Ru thin films were coated on a MWCNT template at low temperature by atomic layer deposition (ALD) using RuDi and O2 as precursor to prepare Ru-CNT CE and the 0.45 cm2 DSSC device of glass/FTO/TiO2/Dye (N719)/electrolyte (C6DMII, GSCN)/Ru-CNT CE was fabricated. The surface morphology of CEs and the energy conversion efficiency of the DSSC device were characterized by scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), and photocurrent-voltage (I-V) measurement. We confirmed that effective surface of the CE increased linearly as the amount of MWCNT spray increased and the crystallized Ru was deposited very conformally around the MWCNT nano template. Moreover, the efficiency of the DSSC increased up to 3.3% as the amount of MWCNT increased. PMID:25936072

  9. 42. BOILER HOUSE FOURTH FLOOR, FORCED DRAFT FANS ABOVE BOILERS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. BOILER HOUSE FOURTH FLOOR, FORCED DRAFT FANS ABOVE BOILERS (SEE DRAWING Nos. 10 & 11 OF 13) - Delaware County Electric Company, Chester Station, Delaware River at South end of Ward Street, Chester, Delaware County, PA

  10. 4. INTERIOR, CENTRAL BOILER ROOM, LOWER LEVEL, BOILERS, FROM SOUTHWEST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. INTERIOR, CENTRAL BOILER ROOM, LOWER LEVEL, BOILERS, FROM SOUTHWEST CORNER OF ROOM, LOOKING SOUTHEAST. - Oakland Naval Supply Center, Heating Plant, North of B Street & West of Third Street, Oakland, Alameda County, CA

  11. Interior view of boiler house looking south. Boiler units are ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view of boiler house looking south. Boiler units are on left. - Burnsville Natural Gas Pumping Station, Saratoga Avenue between Little Kanawha River & C&O Railroad line, Burnsville, Braxton County, WV

  12. Method for reinforcing tubing joints

    NASA Technical Reports Server (NTRS)

    Kinzler, J.; Lee, W. S.

    1968-01-01

    Joint repair technique uses a longitudinally split aluminum shield over the joint ferrule and immediately adjacent tubing to reseal or reinforce leaking or weak joints in small tubing. Epoxy resin coating on inside surfaces of the two shield halves provides a tightly sealed bond between shield and tubing.

  13. Corrosion guard tubing nipple

    SciTech Connect

    Guy, W.E.

    1988-09-27

    This patent describes the process of placing a string of tubing in an oil field well; a. the string of tubing when placed extending from the surface of the earth to an oil bearing formation far below the surface, b. the string made from i. a plurality of tubing sections, ii. each section having external threads on each end, and iii. cuffs with internal threads coupling the tubing sections together, c. each of the tubing sections having i. an axis, ii. a wall thickness, and iii. a corrosion resistant coating on its inside bore; wherein the improved method comprises: d. placing a section of tubing into the well with a cuff attached to the upper end at the surface of the earth, e. dropping a corrosion resistant nipple into the cuff, f. the nipple being loose in the cuff, g. attaching an additional section of tubing onto the cuff, and h. screwing the additional section tightly to the cuff.

  14. Development of Self-Powered Wireless-Ready High Temperature Electrochemical Sensors for In-Situ Corrosion Monitoring for Boiler Tubes in Next Generation Coal-based Power Systems

    SciTech Connect

    Liu, Xingbo

    2015-06-30

    The key innovation of this project is the synergy of the high temperature sensor technology based on the science of electrochemical measurement and state-of-the-art wireless communication technology. A novel self-powered wireless high temperature electrochemical sensor system has been developed for coal-fired boilers used for power generation. An initial prototype of the in-situ sensor demonstrated the capability of the wireless communication system in the laboratory and in a pilot plant (Industrial USC Boiler Setting) environment to acquire electrochemical potential and current signals during the corrosion process. Uniform and localized under-coal ash deposit corrosion behavior of Inconel 740 superalloy has been studied at different simulated coal ash hot corrosion environments using the developed sensor. Two typical potential noise patterns were found to correlate with the oxidation and sulfidation stages in the hot coal ash corrosion process. Two characteristic current noise patterns indicate the extent of the corrosion. There was a good correlation between the responses of electrochemical test data and the results from corroded surface analysis. Wireless electrochemical potential and current noise signals from a simulated coal ash hot corrosion process were concurrently transmitted and recorded. The results from the performance evaluation of the sensor confirm a high accuracy in the thermodynamic and kinetic response represented by the electrochemical noise and impedance test data.

  15. 1. EXTERIOR VIEW OF BOILER HOUSE FROM SOUTHWEST. THE BOILER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. EXTERIOR VIEW OF BOILER HOUSE FROM SOUTHWEST. THE BOILER HOUSE WAS USED FOR HEATING THE MILL; HYDRO-ELECTRIC POWER FOR PRODUCTION WAS PURCHASED FROM THE COLUMBUS LIGHT & POWER COMPANY. NORTH END OF 1924 MILL TO RIGHT, c. 1970 WINDOWLESS WEAVE ROOM ADDITION TO LEFT. - Stark Mill, Boiler House, 117 Corinth Road, Hogansville, Troup County, GA

  16. Super Boiler: First Generation, Ultra-High Efficiency Firetube Boiler

    SciTech Connect

    2006-06-01

    This factsheet describes a research project whose goal is to develop and demonstrate a first-generation ultra-high-efficiency, ultra-low emissions, compact gas-fired package boiler (Super Boiler), and formulate a long-range RD&D plan for advanced boiler technology out to the year 2020.

  17. 36. (Credit JTL) Detail of rear of Heine water tube ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. (Credit JTL) Detail of rear of Heine water tube boiler showing steam drum inspection manhole and blow-down valve. Note inspection plugs for water tubes in tube header below drum. - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

  18. View north of tube bending shop in boilermakers department located ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View north of tube bending shop in boilermakers department located in southeast corner of the structural shop building (building 57). The computer controlled tube bender can be programmed to bend boiler tubing to nearly any required configuration - Naval Base Philadelphia-Philadelphia Naval Shipyard, Structure Shop, League Island, Philadelphia, Philadelphia County, PA

  19. 11. RW Meyer Sugar Mill: 18761889. Locomotive=type, firetube, portable boiler, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. RW Meyer Sugar Mill: 1876-1889. Locomotive=type, fire-tube, portable boiler, model No. 1, Manufactured by Ames Iron Works, Oswego, New York, 1879. 120 lbs./sq. in. working pressure, 66 sq. ft. heating surface in tubes. View: the boiler provided steam for steam engine which in turn powered the centrifugals. View shows front fire box, end of boiler. Below fire-box,used for removing ashes, is a door. Circular openings at the rear of the fire-box are where fire-tubes connected with furnace. Column to right of fire-box carried pressure and water level gauges. Fluted chimney-type structure is steam-port, safety valve, and whistle. Weights originally sat on the arm extending from the top of the port and controlled the boiler pressure. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

  20. Flared tube attachment fitting

    NASA Technical Reports Server (NTRS)

    Alkire, I. D.; King, J. P., Jr.

    1980-01-01

    Tubes can be flared first, then attached to valves and other flow line components, with new fitting that can be disassembled and reused. Installed fitting can be disassembled so parts can be inspected. It can be salvaged and reused without damaging flared tube; tube can be coated, tempered, or otherwise treated after it has been flared, rather than before, as was previously required. Fitting consists of threaded male portion with conical seating surface, hexagonal nut with hole larger than other diameter of flared end of tube, and split ferrule.

  1. Making Internal Molds Of Long, Curved Tubes

    NASA Technical Reports Server (NTRS)

    Burley, Richard K.

    1989-01-01

    Mold material carried to internal weld joint and removed after impression taken. Remotely operated device makes impression mold of interior surface of tube at weld joint. Mold provides indication of extent of mismatch between members at joint. Maneuvered to weld inspected through curved tube 3 in. in diameter by 50 in. long. Readily adapted to making molds to measure depth of corrosion in boiler tubes or other pipes.

  2. Characterization and High-Temperature Erosion Behaviour of HVOF Thermal Spray Cermet Coatings

    NASA Astrophysics Data System (ADS)

    Kumar, Pardeep; Sidhu, Buta Singh

    2016-01-01

    High-velocity oxygen fuel (HVOF) thermal spray, carbide-cermet-based coatings are usually employed in high-temperature erosive and erosive-corrosive environments. Extensive literature is available on high-temperature erosion performance of HVOF coatings under moderate to low particle flux and velocities for application in boiler tubes. This research work presents the characterization and high-temperature erosion behaviour of Cr3C2-25NiCr and WC-10Co-4Cr HVOF-sprayed coatings. Coatings were formulated on the substrate steel of type AISI 304, commonly used for the fabrication of pulverized coal burner nozzles (PCBN). Erosion testing was carried out in high-temperature air-jet erosion tester after simulating the conditions akin to that prevailing in PCBN in the boiler furnace. The coatings were tested for erosion behaviour at different angles and temperatures by freezing other test parameters. Brittle erosion behaviour was depicted in erosion testing, and the coatings couldn't restrain the erodent attacks to protect the substrate. High particle velocity and high particle flux were attributed to be the reasons of extensive erosive weight loss of the coatings. The surface morphology of the eroded specimens was analysed from back-scattered electron images to depict the probable mechanism of material removal. The coatings were characterized with optical microscopy, SEM-EDS analysis, XRD analysis, micro-hardness testing, porosity measurements, surface roughness testing and bond strength testing. The work was undertaken to investigate the performance of the selected coatings in highly erosive environment, so as to envisage their application in PCBNs for protection against material degradation. The coatings could only sustain in oblique impact erosion at room temperature and depleted fully under all other conditions.

  3. Tube support

    DOEpatents

    Mullinax, Jerry L.

    1988-01-01

    A tube support for supporting horizontal tubes from an inclined vertical support tube passing between the horizontal tubes. A support button is welded to the vertical support tube. Two clamping bars or plates, the lower edges of one bearing on the support button, are removably bolted to the inclined vertical tube. The clamping bars provide upper and lower surface support for the horizontal tubes.

  4. Superheater Corrosion In Biomass Boilers: Today's Science and Technology

    SciTech Connect

    Sharp, William

    2011-12-01

    This report broadens a previous review of published literature on corrosion of recovery boiler superheater tube materials to consider the performance of candidate materials at temperatures near the deposit melting temperature in advanced boilers firing coal, wood-based fuels, and waste materials as well as in gas turbine environments. Discussions of corrosion mechanisms focus on the reactions in fly ash deposits and combustion gases that can give corrosive materials access to the surface of a superheater tube. Setting the steam temperature of a biomass boiler is a compromise between wasting fuel energy, risking pluggage that will shut the unit down, and creating conditions that will cause rapid corrosion on the superheater tubes and replacement expenses. The most important corrosive species in biomass superheater corrosion are chlorine compounds and the most corrosion resistant alloys are typically FeCrNi alloys containing 20-28% Cr. Although most of these materials contain many other additional additions, there is no coherent theory of the alloying required to resist the combination of high temperature salt deposits and flue gases that are found in biomass boiler superheaters that may cause degradation of superheater tubes. After depletion of chromium by chromate formation or chromic acid volatilization exceeds a critical amount, the protective scale gives way to a thick layer of Fe{sub 2}O{sub 3} over an unprotective (FeCrNi){sub 3}O{sub 4} spinel. This oxide is not protective and can be penetrated by chlorine species that cause further acceleration of the corrosion rate by a mechanism called active oxidation. Active oxidation, cited as the cause of most biomass superheater corrosion under chloride ash deposits, does not occur in the absence of these alkali salts when the chloride is present as HCl gas. Although a deposit is more corrosive at temperatures where it is molten than at temperatures where it is frozen, increasing superheater tube temperatures through

  5. Intermetallic-ceramic coatings for metals protection against erosion-corrosion at high temperatures

    SciTech Connect

    Wang, B.Q.; Verstak, A.; Beliaev, A.

    1999-07-01

    A series of erosion-corrosion (E-C) tests was carried out on the NiAl-Al{sub 2}O{sub 3} intermetallic-ceramic coatings deposited with high-velocity oxygen-fuel method (HVOF). The tests attempted to simulate the erosion conditions at the heat exchanger tubes in coal-fired boilers. The E-C behavior of these coatings was investigated and compared with other thermal sprayed coatings. It was found that in comparison to other coatings, eroded by the bed ash at 300 C, the HVOF NiAl-40Al{sub 2}0{sub 3} coating exhibited the lowest thickness loss at a 90{degree} impact angle, and was the second best at a 30{degree} impact angle. Eroded by the fly ash under test temperatures 450--600 C, the HVOF NiAl-40Al{sub 2}O{sub 3} coating demonstrated the highest erosion-corrosion resistance at all impact angles of testing. At temperatures below 200 C, the E-C wastage of the HVOF NiAl-40Al{sub 2}O{sub 3} coating had essentially no dependence on temperature. From 200 C to 600 C the coating thickness loss increased and from 600 to 800 C the thickness loss decreased with temperature. The HVOF NiAl-40Al{sub 2}O{sub 3} coating eroded by cracking and chipping brittle mechanism.

  6. Studies of Degraded Smelt Spout Opening Tubes

    SciTech Connect

    Keiser, James R; Kish, Joseph R.; Willoughby, Adam W; Longmire, Hu Foster; Singbeil, Douglas

    2007-01-01

    Co-extruded type 304L stainless steel/SA210 carbon steel tubes have been used on the floors and lower walls of many black liquor recovery boilers to address the wall thinning problem that had been an issue for boiler owners and operators. Use of these tubes greatly reduced the corrosion issue, but corrosion was still sometimes observed and cracking was discovered in some tubes, particularly those that are bent to form the openings for smelt spouts. Because cracks in the opening tubes were sometimes observed to extend a significant distance into the tube wall and because these cracks were found fairly frequently, tubes made from a number of alternate cladding materials were tried in place of the 304L clad opening tubes. This paper describes the results of examinations of spout opening tubes of the standard 304L/carbon steel and of several of the alternate materials that have been tried. In addition to the corrosion and cracking seen in the spout opening tubes, another issue associated with these tubes has been observed. Preferential corrosion of the cap welds is sometimes seen on butt welds attaching the spout opening tubes made with alternate cladding materials to the standard 304L/carbon steel co-extruded wall tubes. Some information on the observations of this corrosion is also included in this paper.

  7. Computer method for identification of boiler transfer functions

    NASA Technical Reports Server (NTRS)

    Miles, J. H.

    1971-01-01

    An iterative computer method is described for identifying boiler transfer functions using frequency response data. An objective penalized performance measure and a nonlinear minimization technique are used to cause the locus of points generated by a transfer function to resemble the locus of points obtained from frequency response measurements. Different transfer functions can be tried until a satisfactory empirical transfer function to the system is found. To illustrate the method, some examples and some results from a study of a set of data consisting of measurements of the inlet impedance of a single tube forced flow boiler with inserts are given.

  8. Feeding Tubes

    MedlinePlus

    ... administer the TPN. Tubes Used for Enteral Feeds NG (Nasogastric Tube) A flexible tube is placed via ... down through the esophagus into the stomach. The NG tube can be used to empty the stomach ...

  9. Ear Tubes

    MedlinePlus

    ... Meeting Calendar Find an ENT Doctor Near You Ear Tubes Ear Tubes Patient Health Information News media ... and throat specialist) may be considered. What are ear tubes? Ear tubes are tiny cylinders placed through ...

  10. Demonstration of coal reburning for cyclone boiler NO{sub x} control. Appendix, Book 1

    SciTech Connect

    Not Available

    1994-06-01

    Based on the industry need for a pilot-scale cyclone boiler simulator, Babcock Wilcox (B&W) designed, fabricated, and installed such a facility at its Alliance Research Center (ARC) in 1985. The project involved conversion of an existing pulverized coal-fired facility to be cyclone-firing capable. Additionally, convective section tube banks were installed in the upper furnace in order to simulate a typical boiler convection pass. The small boiler simulator (SBS) is designed to simulate most fireside aspects of full-size utility boilers such as combustion and flue gas emissions characteristics, fireside deposition, etc. Prior to the design of the pilot-scale cyclone boiler simulator, the various cyclone boiler types were reviewed in order to identify the inherent cyclone boiler design characteristics which are applicable to the majority of these boilers. The cyclone boiler characteristics that were reviewed include NO{sub x} emissions, furnace exit gas temperature (FEGT) carbon loss, and total furnace residence time. Previous pilot-scale cyclone-fired furnace experience identified the following concerns: (1) Operability of a small cyclone furnace (e.g., continuous slag tapping capability). (2) The optimum cyclone(s) configuration for the pilot-scale unit. (3) Compatibility of NO{sub x} levels, carbon burnout, cyclone ash carryover to the convection pass, cyclone temperature, furnace residence time, and FEGT.