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Sample records for boiler tube fouling

  1. Surface chemistry interventions to control boiler tube fouling - Part II

    Energy Technology Data Exchange (ETDEWEB)

    Turner, C.W.; Guzonas, D.A.; Klimas, S.J

    2004-06-15

    This is the third in a series of reports from an investigation co-funded by the Electric Power Research Institute (EPRI) and by Atomic Energy of Canada Limited (AECL) into the effectiveness of alternative amines for controlling the rate of tube-bundle fouling under steam generator (SG) operating conditions. The objectives of this investigation are to determine whether the fouling rate depends on the amine used for pH control, to identify those factors that influence the effectiveness, and use this information to optimize the selection of an amine for chemistry control and deposit control in the steam cycle and steam generator, respectively. Work to date has demonstrated that the rate of particle deposition under steam generator operating conditions is strongly influenced by surface chemistry (Turner et al., 1997; Turner et al., 1999). This dependence upon surface chemistry is illustrated by the difference between the deposition rates measured for hematite and magnetite, and by the dependence of the particle deposition rate on the amine used for pH control. Deposition rates of hematite were found to be more than 10 times greater than those for magnetite under similar test conditions (Turner et al., 1997). At 270{sup o}C and pH{sub T} 6.2, the surfaces of hematite and magnetite are predicted to be positively charged and negatively charged, respectively (Shoonen, 1994). Measurements of the point of zero charge (PZC) of magnetite at temperatures from 25{sup o}C to 290{sup o}C by Wesolowski et al. (1999) have confirmed that magnetite is negatively charged at the stated conditions. A PZC of 4.2 was measured for Alloy 600 at 25{sup o}C (Balakrishnan and Turner, un-published results), and its surface is expected to remain negatively charged for alkaline chemistry over the temperature range of interest. Therefore, there will be a repulsive force between the surfaces of magnetite particles and Alloy 600 at 270{sup o}C and pH{sub T} 6.2 that is absent for hematite particles

  2. Surface chemistry interventions to control boiler tube fouling

    International Nuclear Information System (INIS)

    The adsorption of ammonia, morpholine, ethanolamine, and dimethylamine onto the surfaces of colloidal magnetite and hematite was measured at 25oC. The effect of the adsorption on the surface potential was quantified by measuring the resulting shift in the isoelectric point of the corrosion products and by the direct measurement of the surface interaction force between the corrosion products and Inconel 600. These measurements have served to support the hypothesis that adsorption of amine affects the magnetite deposition rate by lowering the force of repulsion between magnetite and the surface of Inconel 600. The deposition rate of hematite increased as the oxygen concentration increased. A mechanism to account for enhanced deposition rates at high mixture qualities (> 0.35) has been identified and shown to predict behaviour that is consistent with both experimental and plant data. As a result of this investigation, several criteria are proposed to reduce the extent of corrosion product deposition on the tube bundle. Low hematite deposition is favoured by a low concentration of dissolved oxygen, and low magnetite deposition is favoured by choosing an amine for pH control that has little tendency to adsorb onto the surface of magnetite. To minimize adsorption the amine should have a high base strength and a large 'footprint' on the surface of magnetite. To prevent enhanced deposition at high mixture qualities, it is proposed that a modified amine be used that will reduce the surface tension or the elasticity of the steam-water interface or both

  3. Fuel sulfur and boiler fouling

    Energy Technology Data Exchange (ETDEWEB)

    Litzke, W.; Celebi, Y.; Butcher, T. [Brookhaven National Lab., Upton, NY (United States)

    1995-04-01

    Fouling of the heat transfer surfaces of boilers and furnaces by `soot` leads to reduced efficiency and increased service requirements. The average level of annual efficiency reduction as a result of fouling if generally accepted as 2% per year. Improving the efficiency of equipment in the field may be the most important oil heat conservation opportunity at present. Improvements can be realized by reducing fouling rates, promoting lower firing rates in existing equipment, and enabling excess air levels to be set lower without raising concerns about increased service requirements. In spite of the importance of efficiency in the field there is very little data available on efficiency degradation rates with modern equipment, actual field operating conditions (excess air and smoke number settings) and service problems which affect efficiency. During 1993-94 field tests were initiated to obtain such data and to obtain information that would compliment existing and current laboratory work. Experimental work conducted on a bench scale level have included tests with various advanced burners, fuel types, and different operating conditions which have been done at the BNL Rapid Fouling Test Facility. This report will focus on the field study of fouling effects on ten residential heating service problems at each site are summarized. In addition, the technical difficulties involved with conducting such a field study shall also be discussed as the findings should serve to improve future work in this area.

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

    International Nuclear Information System (INIS)

    Rates for the deposition of magnetite and hematite particles onto Alloy 600 surfaces, and for magnetite particles depositing onto surfaces prefouled with sintered porous magnetite deposits were measured. The measurements were made in a high-temperature loop, under typical steam generator operating conditions, with pH controlled using morpholine, ethanolamine, ammonia, dimethylamine, or potassium hydroxide. Deposition rates were compared as a function of the nature of the particle, tube surface morphology, and the reagent used for pH control for steam qualities ranging up to 50%. Conclusions drawn from this work 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 nature of the amine used for pH control affects the magnetite deposition rate. The lowest deposition rate for magnetite is obtained when dimethylamine is used for pH control; the deposition rate of magnetite increases with 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 tube 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 high steam qualities; and here is no evidence that the volatility of the amine affects the deposition behaviour. (author)

  5. The effect of alternative amines on the rate of boiler tube fouling

    Energy Technology Data Exchange (ETDEWEB)

    Turner, C.W.; Klimas, S.J.; Brideau, M.G

    1997-10-01

    Rates for the deposition of magnetite and hematite particles onto Alloy 600 surfaces, and for magnetite particles depositing onto surfaces prefouled with sintered porous magnetite deposits were measured. The measurements were made in a high-temperature loop, under typical steam generator operating conditions, with pH controlled using morpholine, ethanolamine, ammonia, dimethylamine, or potassium hydroxide. Deposition rates were compared as a function of the nature of the particle, tube surface morphology, and the reagent used for pH control for steam qualities ranging up to 50%. Conclusions drawn from this work 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 nature of the amine used for pH control affects the magnetite deposition rate. The lowest deposition rate for magnetite is obtained when dimethylamine is used for pH control; the deposition rate of magnetite increases with 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 tube 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 high steam qualities; and here is no evidence that the volatility of the amine affects the deposition behaviour. (author)

  6. Predictive modelling of boiler fouling. Final report.

    Energy Technology Data Exchange (ETDEWEB)

    Chatwani, A

    1990-12-31

    A spectral element method embodying Large Eddy Simulation based on Re- Normalization Group theory for simulating Sub Grid Scale viscosity was chosen for this work. This method is embodied in a computer code called NEKTON. NEKTON solves the unsteady, 2D or 3D,incompressible Navier Stokes equations by a spectral element method. The code was later extended to include the variable density and multiple reactive species effects at low Mach numbers, and to compute transport of large particles governed by inertia. Transport of small particles is computed by treating them as trace species. Code computations were performed for a number of test conditions typical of flow past a deep tube bank in a boiler. Results indicate qualitatively correct behavior. Predictions of deposition rates and deposit shape evolution also show correct qualitative behavior. These simulations are the first attempts to compute flow field results at realistic flow Reynolds numbers of the order of 10{sup 4}. Code validation was not done; comparison with experiment also could not be made as many phenomenological model parameters, e.g., sticking or erosion probabilities and their dependence on experimental conditions were not known. The predictions however demonstrate the capability to predict fouling from first principles. Further work is needed: use of large or massively parallel machine; code validation; parametric studies, etc.

  7. Knowledge based system for fouling assessment of power plant boiler

    International Nuclear Information System (INIS)

    The paper presents the design of an expert system for fouling assessment in power plant boilers. It is an on-line expert system based on selected criteria for the fouling assessment. Using criteria for fouling assessment based on 'clean' and 'not-clean' radiation heat flux measurements, the diagnostic variable are defined for the boiler heat transfer surface. The development of the prototype knowledge-based system for fouling assessment in power plants boiler comprise the integrations of the elements including knowledge base, inference procedure and prototype configuration. Demonstration of the prototype knowledge-based system for fouling assessment was performed on the Sines power plant. It is a 300 MW coal fired power plant. 12 fields are used with 3 on each side of boiler

  8. Influence of Combustion Parameters on Fouling Composition after Wood Pellet Burning in a Lab-Scale Low-Power Boiler

    Directory of Open Access Journals (Sweden)

    Lara Febrero

    2015-09-01

    Full Text Available The present study aims to evaluate the effect of different operating conditions on fouling composition after woody biomass combustion in an experimental low-power fixed-bed boiler. The boiler was built specifically for research purposes and allows easy removal of areas susceptible to fouling and the control, modification and registry of combustion parameters. The influences of the total airflow supplied and the deposition probe temperature were studied in fouling; differentiating between the layers of fouling adhered to the tube and those deposited over the tube. Thermogravimetry and Differential Scanning Calorimetry (TG-DSC and Scanning Electron Microscopy with Energy Dispersive X-Ray Spectroscopy (SEM-EDS were performed in order to determine a relationship between the fouling composition and the combustion parameters used. Upon increasing the total airflow supplied and the deposition probe temperature, the amount of organic matter, namely unburned carbon, decreased, indicating a better combustion efficiency. Chemical analysis results of fouling deposits showed that inorganic elements presented different behaviors depending on the collection area and the combustion parameters. Non-volatile elements such as Si and Ca were mostly found in the coarse fraction of the bottom ash and minor amounts were deposited over the tube. Small amounts of Cl in biomass generated serious deposition problems, especially during combustions with low airflow rates.

  9. Fouling characteristics of compact heat exchangers and enhanced tubes.

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, C. B.; Rabas, T. J.

    1999-07-15

    Fouling is a complex phenomenon that (1) encompasses formation and transportation of precursors, and (2) attachment and possible removal of foulants. A basic understanding of fouling mechanisms should guide the development of effective mitigation techniques. The literature on fouling in complex flow passages of compact heat exchangers is limited; however, significant progress has been made with enhanced tubes.

  10. Stress-Assisted Corrosion in Boiler Tubes

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. Microphone Detects Boiler-Tube Leaks

    Science.gov (United States)

    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.

  12. Removal of External Deposits on Boiler Tubes

    Directory of Open Access Journals (Sweden)

    C. P. De

    1970-07-01

    Full Text Available The superheater tubes in Port and Starboard boilers were found to have completely clogged by heavy deposits, which on analysis mainly vanadium pentoxide and sodium sulphmatter. The cleaning of the deposits was accomplished by alternate spraying with 15-20 per cent hydrogen peroxide and washing with hot water jets. Over the past two years, since the date of cleaning, the IN ship is operating without any trouble in the boilers.

  13. CFD modeling of a boiler's tubes rupture

    International Nuclear Information System (INIS)

    This paper reports the results of a study on the reason for tubes damage in the superheater Platen section of the 320 MW Bisotoun power plant, Iran. The boiler has three types of superheater tubes and the damage occurs in a series of elbows belongs to the long tubes. A three-dimensional modeling was performed using an in-house computational fluid dynamics (CFD) code in order to explore the reason. The code has ability of simultaneous solving of the continuity, the Reynolds-Averaged Navier-Stokes (RANS) equations and employing the turbulence, combustion and radiation models. The whole boiler including; walls, burners, air channels, three types of tubes, etc., was modeled in the real scale. The boiler was meshed into almost 2,000,000 tetrahedral control volumes and the standard k-ε turbulence model and the Rosseland radiation model were used in the model. The theoretical results showed that the inlet 18.9 MPa saturated steam becomes superheated inside the tubes and exit at a pressure of 17.8 MPa. The predicted results showed that the temperature of the steam and tube's wall in the long tubes is higher than the short and medium size tubes. In addition, the predicted steam mass flow rate in the long tube was lower than other ones. Therefore, it was concluded that the main reason for the rupture in the long tubes elbow is changing of the tube's metal microstructure due to working in a temperature higher than the design temperature. In addition, the structural fatigue tension makes the last elbow of the long tube more ready for rupture in comparison with the other places. The concluded result was validated by observations from the photomicrograph of the tube's metal samples taken from the damaged and undamaged sections

  14. Smooth Surfaces: A review of current and planned smooth surface technologies for fouling resistance in boiler

    Energy Technology Data Exchange (ETDEWEB)

    Corkery, Robert; Baefver, Linda; Davidsson, Kent; Feiler, Adam

    2012-02-15

    Here we have described the basics of boilers, fuels, combustion, flue gas composition and mechanisms of deposition. We have reviewed coating technologies for boiler tubes, including their materials compositions, nano structures and performances. The surface forces in boilers, in particular those relevant to formation of unwanted deposits in boilers have also been reviewed, and some comparative calculations have been included to indicate the procedures needed for further study. Finally practical recommendations on the important considerations in minimizing deposition on boiler surfaces are made

  15. Fouling of the cooling surfaces in biofuel-fired fluidized bed boilers

    Energy Technology Data Exchange (ETDEWEB)

    Peltola, K.; Hiltunen, M.; Blomqvist, J.P.; Skrifvars, B.J.; Kurkela, J.; Latva-Somppi, J.; Kauppinen, E.I.

    1999-07-01

    Fluidized bed combustion has the capability of burning low-grade fuels effectively. These fuels include wood, wood wastes and agrobiofuels, as well as demolition wood and recycled fuels. However, biofuel combustion has occasionally suffered, e.g., from bed material sintering and fouling of superheaters and other cooling surfaces. These symptoms have restricted the wide utilization of new biofuels and energy fractions of material recycling. The fouling tendency of fuels is not dependent on their ash content only. More important factors are the composition of the ash formed in the combustion and the ash mineral reactions. The mechanisms of the deposit formation, origin of ash compounds and their vaporization were studied in cooperation with the Technical Research Centre of Finland (VTT) and Aebo Akademi University. Deposits on tube heat exchangers were collected by using a temperature controlled deposit probe. Short probe tests were used for studying the deposit at the initial state of formation. The formation mechanisms of ash particles and deposits were studied with measurements of fly ash particle size distribution by VTT. The impaction of partly molten particles is anticipated to cause drastic fouling. Aebo Akademi University studied the ash reactions with their novel ash predictor, where the elementary composition of the fuel ash was used for equilibrium calculations. The tests were carried out at a 66 MW{sub th} BFB boiler firing wood chips, bark and saw dust as the main fuels and co-firing green forest residue, chipboard and peat. Peat firing tests were carried out to find out the effect of silicate minerals in ash as well as the effect of sulfur on deposition.

  16. Computer simulation of the fire-tube boiler hydrodynamics

    Science.gov (United States)

    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.

  17. Computer simulation of the fire-tube boiler hydrodynamics

    Directory of Open Access Journals (Sweden)

    Khaustov Sergei A.

    2015-01-01

    Full Text Available 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.

  18. Fouling of HVAC fin and tube heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, Jeffrey; Carey, Van P.

    2001-07-01

    Fin and tube heat exchangers are used widely in residential, commercial and industrial HVAC applications. Invariably, indoor and outdoor air contaminants foul these heat exchangers. This fouling can cause decreased capacity and efficiency of the HVAC equipment as well as indoor air quality problems related to microbiological growth. This paper describes laboratory studies to investigate the mechanisms that cause fouling. The laboratory experiments involve subjecting a 4.7 fins/cm (12 fins/inch) fin and tube heat exchanger to an air stream that contains monodisperse particles. Air velocities ranging from 1.5-5.2 m/s (295 ft/min-1024 ft/min) and particle sizes from 1--8.6 {micro}m are used. The measured fraction of particles that deposit as well as information about the location of the deposited material indicate that particles greater than about 1 {micro}m contribute to fouling. These experimental results are used to validate a scaling analysis that describes the relative importance of several deposition mechanisms including impaction, Brownian diffusion, turbophoresis, thermophoresis, diffusiophoresis, and gravitational settling. The analysis is extended to apply to different fin spacings and particle sizes typical of those found in indoor air.

  19. CONCENTRIC TUBE-FOULING RIG FOR INVESTIGATION OF FOULING DEPOSIT FORMATION FROM PASTEURISER OF VISCOUS FOOD LIQUID

    Directory of Open Access Journals (Sweden)

    N. I. KHALID

    2013-02-01

    Full Text Available This paper reports the work on developing concentric tube-fouling rig, a new fouling deposit monitoring device. This device can detect and quantify the level of fouling deposit formation. It can also functioning as sampler for fouling deposit study, which can be attached at any food processing equipment. The design is initiated with conceptual design. The rig is designed with inner diameter of 7 cm and with tube length of 37 cm. A spiral insert with 34.5 cm length and with 5.4 cm diameter is fitted inside the tube to ensure the fluid flows around the tube. In this work, the rig is attached to the lab-scale concentric tube-pasteurizer to test its effectiveness and to collect a fouling sample after pasteurization of pink guava puree. Temperature changes are recorded during the pasteurization and the data is used to plot the heat transfer profile. Thickness of the fouling deposit is also measured. The trends for thickness, heat resistance profile and heat transfer profile for concentric tube-fouling rig matched the trends obtained from lab-scale concentric tube-pasteurizer very well. The findings from this work have shown a good potential of this rig however there is a limitation with spiral insert, which is discussed in this paper.

  20. CFD Studies on Multi Lead Rifled [MLR] Boiler Tubes

    OpenAIRE

    Dr T C Mohankumar

    2013-01-01

    This paper reports the merits of multi lead rifled [MLR] tubes in vertical water tube boiler using CFD tool. Heat transfer enhancement of MLR tubes was mainly taken in to consideration. Performance of multi lead rifled tube was studied by varying its influencing geometrical parameter like number of rifling, height of rifling, length of pitch of rifling for a particular length. The heat transfer analysis was done at operating conditions of an actual coal fired water tube boiler situated at Apo...

  1. Maintenance of immersion ultrasonic testing on the water tube boiler

    International Nuclear Information System (INIS)

    There are 4-boiler in nuclear fuel cycle engineering laboratories (NCL). These boilers have been operated in the long term over 20 years. One of them, the leakage of boiler water was found at one of the generating tubes, and 2 adjoining generating tubes were corroded in Dec, 2011. These generating tubes were investigated by immersion ultrasonic testing (UT) for measure thickness of the tube. As a result, thinner tube was found in a part of a bend and near the water drum. These parts are covered with sulfide deposit, it seems that the generating tubes were corroded by sulfide. (author)

  2. Influence of Sorbent Characteristics on Fouling and Deposition in Circulating Fluid Bed Boilers Firing High Sulfur Indian Lignite

    Directory of Open Access Journals (Sweden)

    Selvakumaran Palaniswamy

    2013-01-01

    Full Text Available 125 MWe circulating fluidized bed combustion (CFBC boiler experienced severe fouling in backpass of the boiler leading to obstruction of gas flow passage, while using high sulfur lignite with sorbent, calcium carbonate, to capture sulfur dioxide. Optical microscopy of the hard deposits showed mainly anhydrite (CaSO4 and absence of intermediate phases such as calcium oxide or presence of sulfate rims on decarbonated limestone. It is hypothesized that loose unreacted calcium oxides that settle on tubes are subjected to recarbonation and further extended sulfation resulting in hard deposits. Foul probe tests were conducted in selected locations of backpass for five different compositions of lignite, with varied high sulfur and ash contents supplied from the mines along with necessary rates of sorbent limestone to control SO2, and the deposits build-up rate was determined. The deposit build-up was found increasing, with increase in ash content of lignite, sorbent addition, and percentage of fines in limestone. Remedial measures and field modifications to dislodge deposits on heat transfer surfaces, to handle the deposits in ash conveying system, and to control sorbent fines from the milling circuit are explained.

  3. CFD investigation of flow through internally riffled boiler tubes

    DEFF Research Database (Denmark)

    Rasmussen, Christian; Houbak, Niels; Sørensen, Jens Nørkær

    1997-01-01

    In this paper we show how to model the swirling flow in an internally riffled boiler tube. The flow field is visualized and the results are compared with measurements.......In this paper we show how to model the swirling flow in an internally riffled boiler tube. The flow field is visualized and the results are compared with measurements....

  4. Analysis of fouling characteristic in enhanced tubes using multiple heat and mass transfer analogies☆

    Institute of Scientific and Technical Information of China (English)

    Zepeng Wang; Guanqiu Li; Jingliang Xu; Jinjia Wei; Jun Zeng; Decang Lou; Wei Li

    2015-01-01

    This paper provides a comprehensive analysis on cooling tower fouling data taken from seven 15.54 mm I.D. helically ribbed, copper tubes and a plain tube at Re=16000. There are two key processes during fouling formation:fouling deposition and fouling removal, which can be determined by mass transfer and fluid friction respectively. The mass transfer coefficient can be calculated through three analogies:Prandtl analogy, Von–Karman analogy, and Chilton–Colburn analogy. Based on our analyses, Von–Karman analogy is the optimized analogy, which can well predict the formation of cooling tower fouling. Series of semi-theoretical fouling correlations as a function of the product of area indexes and efficiency indexes were developed, which can be applicable to different internally ribbed geometries. The correlations can be directly used to assess the fouling potential of enhanced tubes in actual cooling tower water situations.

  5. CFD Studies on Multi Lead Rifled [MLR] Boiler Tubes

    Directory of Open Access Journals (Sweden)

    Dr T C Mohankumar

    2013-09-01

    Full Text Available This paper reports the merits of multi lead rifled [MLR] tubes in vertical water tube boiler using CFD tool. Heat transfer enhancement of MLR tubes was mainly taken in to consideration. Performance of multi lead rifled tube was studied by varying its influencing geometrical parameter like number of rifling, height of rifling, length of pitch of rifling for a particular length. The heat transfer analysis was done at operating conditions of an actual coal fired water tube boiler situated at Apollo Tyres LTD, Chalakudy, India for saturated process steam production. The results showed that the heat transfer increased when compared with existing inner plane wall water tubes.

  6. Ash fouling monitoring and key variables analysis for coal fired power plant boiler

    Directory of Open Access Journals (Sweden)

    Shi Yuanhao

    2015-01-01

    Full Text Available Ash deposition on heat transfer surfaces is still a significant problem in coal-fired power plant utility boilers. The effective ways to deal with this problem are accurate on-line monitoring of ash fouling and soot-blowing. In this paper, an online ash fouling monitoring model based on dynamic mass and energy balance method is developed and key variables analysis technique is introduced to study the internal behavior of soot-blowing system. In this process, artificial neural networks (ANN are used to optimize the boiler soot-blowing model and mean impact values method is utilized to determine a set of key variables. The validity of the models has been illustrated in a real case-study boiler, a 300MW Chinese power station. The results on same real plant data show that both models have good prediction accuracy, while the ANN model II has less input parameters. This work will be the basis of a future development in order to control and optimize the soot-blowing of the coal-fired power plant utility boilers.

  7. Development of the boiler tube wall thickness ultrasonic detector

    International Nuclear Information System (INIS)

    Wall thickness of fossil fuel firing power boiler tubes are measured by ultrasonic test at regular intervals as part of in-service inspections. The measuring tubes are located high up on the boiler and at restricted sites, and many man-hours are required for preparatory of boiler tube wall thickness scale removal. To improve the efficiency and reliability of boiler tube wall thickness measurements, a system was developed for measuring the tube wall thickness by ultrasonic test from inside the tube. The primary features of this system are: 1) polishing on the outersurface of boiler tubes is not necessary because measurements are made from inside. (Reduction of man-hours), 2) measurements in limited places where manual measurement is difficult or impossible is made possible because automatic measurement from inside the tube is made by an ultrasonic probe introduced into the tube from the inspection hole of the header. (Improvement of reliability), and 3) the tube wall thickness is measured by a submerged ultrasonic rotary probe at an accuracy of ±0.1 mm along the full length. (Improvement of reliability)

  8. A Comparative Study of Fouling and Bottom Ash from Woody Biomass Combustion in a Fixed-Bed Small-Scale Boiler and Evaluation of the Analytical Techniques Used

    Directory of Open Access Journals (Sweden)

    Lara Febrero

    2015-05-01

    Full Text Available In this work, fouling and bottom ash were collected from a low-power boiler after wood pellet combustion and studied using several analytical techniques to characterize and compare samples from different areas and determine the suitability of the analysis techniques employed. TGA results indicated that the fouling contained a high amount of organic matter (70%. The XRF and SEM-EDS measurements revealed that Ca and K are the main inorganic elements and exhibit clear tendency in the content of Cl that is negligible in the bottom ash and increased as it penetrated into the innermost layers of the fouling. Calcite, magnesia and silica appeared as the major crystalline phases in all the samples. However, the bottom ash was primarily comprised of calcium silicates. The KCl behaved identically to the Cl, preferably appeared in the adhered fouling samples. This salt, which has a low melting point, condenses upon contact with the low temperature tube and played a crucial role in the early stages of fouling formation. XRD was the most useful technique applied, which provided a semi-quantitative determination of the crystalline phases. FTIR was proven to be inadequate for this type of sample. The XRF and SEM-EDS, techniques yield similar results despite being entirely different.

  9. Failure analysis of boiler tubes in lakhra coal power plant

    International Nuclear Information System (INIS)

    Present work deals with the failure analysis of a boiler tube in Lakhra fluidized bed combustion power station. Initially, visual inspection technique was adopted to analyse the fractured surface. Detailed microstructural investigations of the busted boiler tube were carried out using light optical microscope and scanning electron microscope. The hardness tests were also performed. A 50 percent decrease in hardness of intact portion of the tube material and from area adjacent to failure was measured, which was found to be in good agreement with the wall thicknesses measured of the busted boiler tube i.e. 4 mm and 2 mm from unaffected portion and ruptured area respectively. It was concluded that the major cause of failure of boiler tube is erosion of material which occurs due the coal particles strike at the surface of the tube material. Since the temperature of boiler is not maintained uniformly. The variations in boiler temperature can also affect the material and could be another reason for the failure of the tube. (author)

  10. Investigations of ash fouling with cattle wastes as reburn fuel in a small-scale boiler burner under transient conditions.

    Science.gov (United States)

    Oh, Hyukjin; Annamalai, Kalyan; Sweeten, John M

    2008-04-01

    Fouling behavior under reburn conditions was investigated with cattle wastes (termed as feedlot biomass [FB]) and coal as reburn fuels under a transient condition and short-time operation. A small-scale (30 kW or 100,000 Btu/hr) boiler burner research facility was used for the reburn experiments. The fuels considered for these experiments were natural gas (NG) for the ashless case, pure coal, pure FB, and blends of coal and FB. Two parameters that were used to characterize the ash "fouling" were (1) the overall heat-transfer coefficient (OHTC) when burning NG and solid fuels as reburn fuels, and (2) the combustible loss through ash deposited on the surfaces of heat exchanger tubes and the bottom ash in the ash port. A new methodology is presented for determining ash-fouling behavior under transient conditions. Results on the OHTCs for solid reburn fuels are compared with the OHTCs for NG. It was found that the growth of the layer of ash depositions over longer periods typically lowers OHTC, and the increased concentration of ash in gas phase promotes radiation in high-temperature zones during initial periods while decreasing the heat transfer in low-temperature zones. The ash analyses indicated that the bottom ash in the ash port contained a smaller percentage of combustibles with a higher FB percentage in the fuels, indicating better performance compared with coal because small particles in FB burn faster and the FB has higher volatile matter on a dry ash-free basis promoting more burn out.

  11. Failure of marine boiler tube: A case history

    Directory of Open Access Journals (Sweden)

    V. A. Dere

    1963-01-01

    Full Text Available An interesting case of marine boiler tube failure is described. As a result of local overheating, a ballooning burst occurred in a boiler tube. Evidence showed that a temperature of over 1600/degree/F (87/degree/C had been reached before rupture. The presence of a thin film of copper arising from the auxiliary equipments of the boiler, caused pittings in the metal. failure was thus attributed to local overheating accelerated by an inner deposit of heat insulating scale.

  12. Boiler tube corrosion characterization with a scanning thermal line

    Science.gov (United States)

    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.

  13. Modelling and simulating fire tube boiler performance

    DEFF Research Database (Denmark)

    Sørensen, Kim; Karstensen, Claus; Condra, Thomas Joseph;

    2003-01-01

    A model for a ue gas boiler covering the ue gas and the water-/steam side has been formulated. The model has been formulated as a number of sub models that are merged into an overall model for the complete boiler. Sub models have been dened for the furnace, the convection zone (split in 2: a zone...

  14. Thermal Characteristics of Tube Bundles in Ultra-Supercritical Boilers

    Directory of Open Access Journals (Sweden)

    Seok Min Choi

    2016-09-01

    Full Text Available In this study, flow and thermal characteristics of tube bundles in ultra-supercritical boilers were analyzed. The local heat transfer around the tube bundles was measured to predict the local temperature distribution and vulnerable positions of the superheated tube bundles. The maximally superheated tube bundles were simulated in the laboratory and local heat transfer was measured by using the naphthalene sublimation method. The experiment was conducted on three lines of tube bundles, all with in-line arrangements. Each line consist of six tubes. The distance in the streamwise direction (Sx/∅ was 1.99 and that in the spanwise direction (Sz/∅ was 5.45. The Reynolds number varied from 5000 to 30,000, which covers a range of different operating conditions. Thermal and stress analyses were conducted numerically, based on the experimental data. The results showed that the flow characteristic changes the local heat transfer of the tube bundles. The flow impinged on the stagnation point of Tube 1 and reattached at 60° of Tube 2. The high heat transfer occurred at those positions of the tube bundles. The temperature and stress distributions on the surface of each tube bundle also varied. The reattachment point on Tube 2 had the highest heat transfer and temperature distribution. That position on Tube 2 was subjected to the highest stress due to the large temperature gradient. This result indicates that Tube 2 of the ultra-supercritical (USC boiler is the weakest of the tube bundles, changing the pitch of the streamwise direction of Tube 2 is one method to reduce the highest stress in superheater tube bundles in the USC boiler.

  15. Modelling and simulating fire tube boiler performance

    DEFF Research Database (Denmark)

    Sørensen, K.; Condra, T.; Houbak, Niels;

    2003-01-01

    A model for a flue gas boiler covering the flue gas and the water-/steam side has been formulated. The model has been formulated as a number of sub models that are merged into an overall model for the complete boiler. Sub models have been defined for the furnace, the convection zone (split in 2......: a zone submerged in water and a zone covered by steam), a model for the material in the boiler (the steel) and 2 models for resp. the water/steam zone (the boiling) and the steam. The dynamic model has been developed as a number of Differential-Algebraic-Equation system (DAE). Subsequently Mat......Lab/Simulink has been applied for carrying out the simulations. To be able to verify the simulated results experiments has been carried out on a full scale boiler plant....

  16. Simulasi Thermal Stress Pada Tube Superheater Package Boiler

    OpenAIRE

    Hamdani

    2013-01-01

    This project investigates the thermal stress behavior and the mechanisms of superheater tube failure with experimental method and numerical analysis. First of all the procedures for failure analysis were applied to determine the root cause of them. A visual assessment of boiler critical pressure parts was carried out, and then the failed tube is examined by nondestructive evaluation. For the numerical domain, initially the elastic solution for a superheater tube subjected to an internal press...

  17. Boiler Tube Corrosion Characterization with a Scanning Thermal Line

    Science.gov (United States)

    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

  18. Probe Measures Fouling As In Heat Exchangers

    Science.gov (United States)

    Marner, Wilbur J.; Macdavid, Kenton S.

    1990-01-01

    Combustion deposits reduce transfer of heat. Instrument measures fouling like that on gas side of heat exchanger in direct-fired boiler or heat-recovery system. Heat-flux probe includes tube with embedded meter in outer shell. Combustion gases flow over probe, and fouling accumulates on it, just as fouling would on heat exchanger. Embedded heat-flow meter is sandwich structure in which thin Chromel layers and middle alloy form thermopile. Users determine when fouling approaches unacceptable levels so they schedule cleaning and avoid decreased transfer of heat and increased drop in pressure fouling causes. Avoids cost of premature, unnecessary maintenance.

  19. Influence of furnace tube shapeon thermal strain of fire-tube boilers

    Directory of Open Access Journals (Sweden)

    Gaćeša Branka

    2014-01-01

    Full Text Available The aim of this paper is to use numerical analysis and fine element method-FEM to investigate the influence of furnace tube shape on the thermal strain of fire-tube boilers. Thermal stresses in corrugated furnace tubes of different shape, i.e. with different corrugation pitch and depth, were analysed first. It was demonstrated that the thermal stresses in corrugated furnace tube are significantly reduced with the increase of corrugation depth. Than deformations and stresses in the structure of a fire-tube boiler were analysed in a real operating condition, for the cases of installed plain furnace tube and corrugated furnace tubes with different shapes. It was concluded that in this fire-tube boiler, which is of larger steam capacity, the corrugated furnace tube must be installed, as well as that the maximal stress in the construction is reduced by the installation of the furnace tube with greater corrugation depth. The analysis of stresses due to pressure and thermal loads pointed out that thermal stresses are not lower-order stresses in comparison to stresses due to pressure loads, so they must be taken into consideration for boiler strength analysis. [Projekat Ministarstva nauke Republike Srbije, br. TR 35040 i br. TR 35011

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

    Science.gov (United States)

    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.

  1. Study on Acoustic Catheter of Boiler Tube Leakage Monitoring Systems

    Science.gov (United States)

    Lv, Yongxing; Feng, Qiang

    Boiler tube leakage is the major reason of affecting the safe operation of the unit now, there are 3 methods of the "four tube" leakage detection: Traditional method, filtering method and acoustic spectrum analysis, acoustic spectrum analysis is the common method, but this method have low sensitivity and the sensor damage easily. Therewith, designed the special acoustic catheter with acoustic resonance cavity type, proved by experiments, the acoustic catheter with acoustic resonance cavity type can enhance leakage sound, can accurately extract leakage signals, has high sensitivity, and can avoid the effect of sensor by fire and hot-gas when the furnace is in positive pressure situation, reduce the installation and maintenance costs of the boiler tube leakage monitor system.

  2. Corrosion of evaporator tubes in low emission steam boilers

    Directory of Open Access Journals (Sweden)

    S. Topolska

    2010-04-01

    Full Text Available Purpose: of this paper is to reveal the mechanisms of corrosion processes of outer surfaces of low-emission steam boiler evaporator tubes. Examinations were performed to find the reasons of different corrosion susceptibility of tubes situated at combustion chamber on various levels.Design/methodology/approach: Examinations were conducted on several segments of Ø 57 x 5.0 mm evaporator tubes made of 16M (16Mo3 steel grade. Segments were taken from level of 10 meters and 18 meters from the chamber bottom of low-emission coal fired steam boiler after two years operation. Microstructure degradation of base material was estimated. Metallographic evaluation of scale morphology, its micro sites chemical composition analysis and distribution of elements on cross sections have been performed.Findings: Eexaminations of evaporator tubes indicated that reduction of wall thickness was considerable at the segments taken from level of 10 m, when at level of 18 m this reduction was small. The morphology of scales consisted of external layer which was porous and weakly connected to the tube surface, and internal layer, which was dense and adherent to the base metal. In these two layers the bands reach in sulfur were detected. The sulfide corrosion seems to be the main degradation mechanism of the tube surface at the level of 10 m.Research limitations/implications: Corrosion of the water wall tubes in low-emission steam boilers is a result of reaction of steel tube surface with the aggressive substoichiometric environment contains sulfur. The chemical composition of flue gases changes along the water wall. The exact compound of flue gases has not been determined in this study.Practical implications: Prevention of water wall tubes corrosion can be achieved by changing in operation conditions or replacement of tube materials. The first mentioned action is limited to accurate burner’s adjustment or introduces a flow of additional air along the walls and create

  3. A risk approach to the management of boiler tube thinning

    International Nuclear Information System (INIS)

    A large set of industrial thickness inspection data covering four boiler units of a power station over a period of five years was made available to the authors. The measurements were made in regions of the boiler where corrosion/erosion was the major cause of failure of the boiler tubes. There were over 40,000 separately measured data points in the data and all were collected with some care and expense. In the development of maintenance strategies for equipment, this type of data is typical of the data that must be collected and assessed. This data thus represents an opportunity to evaluate the ability to generate a useful risk approach to the management of the tubing. An important example of a risk-based approach is the American Petroleum Institute (API) Risk Based Inspection ('RBI'), API 581. A variety of problems were encountered applying this to boiler tubes. The problems include irrelevant API 581 corrosion rate tables, lack of information on how to analyse inspection data, difficulty of dealing with multiple inspection categories and lack of suitable direction for programming inspection intervals

  4. Modelling of a one pass smoke tube boiler

    DEFF Research Database (Denmark)

    Karstensen, Claus M. S.; Sørensen, Kim

    2004-01-01

    A nonlinear state-space model with five states describing a one pass smoke tube boiler has been formulated. By means of mass- and energy-balance the model describes the dynamics of the Furnace, the Convection Zone and the Water/Steam Part and the three sub models are merged into an overall model....... The model is further linearized for use in a linear control design. The simulations have been carried out by means of MATLAB/SIMULINK and the models have been verified with measurements from a full scale boiler plant. Parameters in the model that are difficult to calculate have been estimated and the method...

  5. Use of genetic algorithm to identify thermophysical properties of deposited fouling in heat exchanger tubes

    International Nuclear Information System (INIS)

    At high temperature, the circulation of fluid in heat exchangers provides a tendency for fouling accumulation to take place on the internal surface of tubes. This paper shows an experimental process of thermophysical properties estimation of the fouling deposited on internal surface of a heat exchanger tube using genetic algorithms (GAs). The genetic algorithm is used to minimize an objective function containing calculated and measured temperatures. The experimental bench using a photothermal method with a finite width pulse heat excitation is used and the estimated parameters are obtained with high accuracy

  6. Fracture in a steam boiler generator tube

    International Nuclear Information System (INIS)

    This study briefly describes the abrupt rupture of a classical heater tube in 15D3 steel (steel rarely used in France). This breakage had occurred after 10 years of service. The authors conclude in a local overheating having provoked an intergranular precipitation, itself triggering a breakage. (Author). 4 refs., 5 figs., 2 tabs

  7. In situ heat exchanger tube fouling thickness measurements using ultrasonics

    Science.gov (United States)

    Hirshman, J.; Munier, R. S. C.

    1980-09-01

    The feasibility of establishing a practical microacoustic technique to measure fouling film thickness in situ on typical ocean thermal energy conversion (OTEC) heat exchanger tasks was studied. Seven techniques were studied for this application, including velocity measurements, acoustic diffraction, acoustic interferometer, Doppler flow velocity, pulse echo, critical angle, and surface (shear) wave effects. Of these, the latter five were laboratory tested using conventional microacoustic system components in various configurations. Only the pulse echo technique yielded promising results. On fouled aluminum plates, thin film layers of 40 microns and greater were measured using focused 30 MHz ceramic transducer operated at 25 MHz; this represents a resolution of about 2/3 wavelength. Measurements made on the inside of fouled 1 inch aluminum pipes yielded film thickness of 75 to 125 microns. The thinnest layer resolved was approximately 1-1/4 wavelength. The resolution of slime layer thickness in the magnitudes of OTEC interest (5 to 30 microns) using pulse echo microacoustics will require transducer development.

  8. Design of shell-and-tube heat exchangers when the fouling depends on local temperature and velocity

    Energy Technology Data Exchange (ETDEWEB)

    Butterworth, D. [HTFS, Hyprotech, Didcot (United Kingdom)

    2002-07-01

    Shell-and-tube heat exchangers are normally designed on the basis of a uniform and constant fouling resistance that is specified in advance by the exchanger user. The design process is then one of determining the best exchanger that will achieve the thermal duty within the specified pressure drop constraints. It has been shown in previous papers [Designing shell-and-tube heat exchangers with velocity-dependant fouling, 34th US national Heat Transfer Conference, 20-22 August 2000, Pittsburg, PA; Designing shell-and-tube heat exchangers with velocity-dependant fouling, 2nd Int. Conf. on Petroleum and Gas Phase Behavior and Fouling, 27-31 August 2000, Copenhagen] that this approach can be extended to the design of exchangers where the design fouling resistance depends on velocity. The current paper briefly reviews the main findings of the previous papers and goes on to treat the case where the fouling depends also on the local temperatures. The Ebert-Panchal [Analysis of Exxon crude-oil, slip-stream coking data, Engineering Foundation Conference on Fouling Mitigation of Heat Exchangers, 18-23 June 1995, California] form of fouling rate equation is used to evaluate this fouling dependence. When allowing for temperature effects, it becomes difficult to divorce the design from the way the exchanger will be operated up to the point when the design fouling is achieved. However, rational ways of separating the design from the operation are proposed. (author)

  9. Influence of boiler load on water tubes burnout

    Energy Technology Data Exchange (ETDEWEB)

    Said, S.A.M.; Habib, M.A.; Badr, H.M.; Mansour, R. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Dept. of Mechanical Engineering

    2009-07-01

    The influence of boiler loads on water tube burnout was investigated. The in-service boiler had 2 burners at different levels located in the front of the burner's wall. Homogenous-flow and separated-flow models were designed to simulate the water circulation and combustion processes inside the boiler tubes. Heat flux calculations were derived by solving the conservation of mass, momentum, and energy equations and species concentration as well as by solving turbulence, reaction rate, and radiation model equations. Results of the study showed that heat flux during full loads ranged from close to 0 to 270 kW/m2. The right side screen wall of the burner exhibited higher heat flux values in the middle region of the wall where large areas were subjected to heat flux close to a maximum of 270 kW/m2. Results also included reductions in heat flux values at partial loads. Maximum values were reduced from 270 kW/m2 ato 230 kW/m2 at 75 per cent capacity and 200 kW/m2 at 60 per cent capacity. The rate of steam generation increased from 0.1 kg/s to 0.153 kg/s when the distance from the burner wall increased from 2 meters to 12 meters. 10 refs., 10 figs.

  10. Enhanced tubes for steam condensers. Volume 1, Summary of condensation and fouling; Volume 2, Detailed study of steam condensation

    Energy Technology Data Exchange (ETDEWEB)

    Webb, R.L.; Chamra, L.; Jaber, H.

    1992-02-01

    Electric utility steam condensers typically use plain tubes made of titanium, stainless steel, or copper alloys. Approximately two-thirds of the total thermal resistance is on the water side of the plain tube. This program seeks to conceive and develop a tube geometry that has special enhancement geometries on the tube (water) side and the steam (shell) side. This ``enhanced`` tube geometry, will provide increased heat transfer coefficients. The enhanced tubes will allow the steam to condense at a lower temperature. The reduced condensing temperature will reduce the turbine heat rate, and increase the plant peak load capability. Water side fouling and fouling control is a very important consideration affecting the choice of the tube side enhancement. Hence, we have consciously considered fouling potential in our selection of the tube side surface geometry. Using appropriate correlations and theoretical models, we have designed condensation and water side surface geometries that will provide high performance and be cleanable using sponge ball cleaning. Commercial tube manufacturers have made the required tube geometries for test purposes. The heat transfer test program includes measurement of the condensation and water side heat transfer coefficients. Fouling tests are being run to measure the waterside fouling resistance, and to the test the ability of the sponge ball cleaning system to clean the tubes.

  11. Hydrogen attack evaluation of boiler tube using ultrasonic wave

    International Nuclear Information System (INIS)

    The presence of hydrogen in industrial plants is a source of damage. Hydrogen attack is one such form of degradation and often causing large tube ruptures that necessitate an immediate shutdown. Hydrogen attack may reduce the fracture toughness as well as the strength of steels. This reduction is caused partially by the presence of cavities and microcracks at the grain boundaries. In the past several techniques have been used with limited results. This paper describes the application of an ultrasonic velocity, attenuation and backscatter techniques for detecting the presence of hydrogen damage in utility boiler tubes. Ultrasonic tests showed a decrease in wave velocity and an increase in attenuation. Such results demonstrate the potential for ultrasonic nondestructive testing to quantify damage. Based on this study, recommendations are that both velocity and attenuation be used to detect hydrogen attack in steels.

  12. New insights into controlling tube-bundle fouling using alternative amines

    International Nuclear Information System (INIS)

    A volatile amine is added to the secondary heat-transport system of a nuclear power plant to reduce the rate of corrosion and corrosion product transport in the feedwater and to protect steam generator (SG) crevices and materials exposed to steam condensate. Volatility and base strength of the amine at the SG operating temperature are two important considerations when choosing the optimum amine (or mixture of amines) for corrosion control in the steam cycle. The investigation has found that the rate of tube-bundle fouling is strongly dependent upon the surface chemistry of the corrosion products. For example, the fouling rates of fully oxidized iron oxides, such as hematite and lepidocrocite, are at least an order of magnitude greater than the fouling rate of magnetite under identical operating conditions. The difference is related to the sign of the surface charge on the corrosion products at temperature. The choice of amine for pH-control also influences the fouling rate. This was originally thought to be a surface-charge effect as well, but recent tests have suggested that it is related to the role that the amine plays in governing the rate of deposit consolidation on the heat-transfer surface. Amines that promote a high rate of deposit consolidation result in a low rate of deposit removal and a high fouling rate. Conversely, amines that tend to inhibit deposit consolidation produce a higher rate of deposit removal and a lower fouling rate. Dimethyl-amine and dodecyl-amine have been identified as two amines that inhibit the rate of deposit consolidation and, consequently, result in fouling rates that are up to 5 times lower than rates measured for amines that promote consolidation. A significant difference between morpholine (high fouling rate) and dimethyl-amine (low fouling rate) is that the latter desorbs more slowly from the surface of magnetite. How to account for a correlation between slow desorption kinetics and lower rate constants for deposition and

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

    Energy Technology Data Exchange (ETDEWEB)

    DuPont, J.N.; Banovic, S.W.; Marder, A.R. [Lehigh Univ., Bethlehem, PA (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Singbeil, D.L.; Prescott, R. [Pulp and Paper Research Inst. of Canada, Vancouver, British Columbia (Canada); Keiser, J.R.; Swindeman, R.W. [Oak Ridge National Lab., TN (United States)

    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.

  15. On-Line Life Monitoring Technique for Tube Bundles of Boiler High-Temperature Heating Surface

    Institute of Scientific and Technical Information of China (English)

    Yang Dong; Wang Zhongyuan

    2005-01-01

    High-temperature heating surface such as superheater and reheater of large-sized utility boiler all experiences a relatively severe working conditions. The failure of boiler tubes will directly impact the safe and economic operation of boiler. An on-line life monitoring model of high-temperature heating surface was set up according to the well-known L-M formula of the creep damages. The tube wall metal temperature and working stress was measured by on-line monitoring, and with this model, the real-time calculation of the life expenditure of the heating surface tube bundles were realized. Based on the technique the on-line life monitoring and management system of high-temperature heating surface was developed for a 300 MW utility boiler. An effective device was thus suggested for the implementation of the safe operation and the condition-based maintenance of utility boilers.

  16. Superheater fouling in a BFB boiler firing wood-based fuel blends

    NARCIS (Netherlands)

    Stam, A.F.; Haasnoot, K.; Brem, G.

    2014-01-01

    Four different fuel blends have been fired in a 28 MWel BFB. Wood pellets (test 0) were not problematic for about ten years, contrary to a mixture of demolition wood, wood cuttings, compost overflow, paper sludge and roadside grass (test 1) which caused excessive fouling at a superheater bundle afte

  17. Life Management Technique of Thermal Fatigue for SMST Boiler Tube at Different Heating Zone Using Smithy Furnace

    OpenAIRE

    Shekhar Pal; Pradeep Suman

    2014-01-01

    This paper highlights on the evaluation of thermal fatigue failure for SMST (Salzgitter Mannesmann strain less boiler tube) DMV 304 HCu boiler tube using life management technique by using of smithy furnace. Boiler tubes are highly affected by operating conditions like, high temperature and high pressure. So it needs periodic checking for the purpose of safety and health assessment of the plant. So using this technique we can identify the degradation of tubes at microstructure...

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

    Science.gov (United States)

    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. Formation of corrosion products protecting surfaces of the boiler proper tubes from the combustion chamber

    OpenAIRE

    Pietrzyk, M.; S. Król

    2007-01-01

    Purpose: The aim of this paper is to determine how the oxidation product layer of the steel applied for the radiant tubes should increase if we are going to obtain the lowest possible corrosion losses.Design/methodology/approach: Boiler tubes, made of 13CrMo4-5 steel were subjected to tests. In the boiler BP-1150, the tubes ø 30 x 5 mm are joined by fins and form a membrane shield. According to the maps of tube wall thickness, in the zone of the highest heat load, sectors of the shield were s...

  20. INVESTIGATION OF FOULING DEPOSIT FORMATION DURING PASTEURIZATION OF CHILI SAUCE BY USING LAB-SCALE CONCENTRIC TUBE-PASTEURIZER

    Directory of Open Access Journals (Sweden)

    NUR ATIKA ALI

    2014-06-01

    Full Text Available This paper investigates the characteristics of fouling deposits obtained from chilli sauce pasteurization. A lab-scale concentric tube-pasteurizer was used to pasteurize the chilli sauce at 0.712 kg/min and 90±5°C. It was operated for 3 hours. Temperature changes were recorded during pasteurization and the data was used to plot the heat transfer profile and the fouling resistance profile. The thickness of the fouling deposit was also measured and the image was taken for every hour. The fouling deposit was collected at every hour to test its stickiness, hardness and flow behaviour. Proximate analysis was also performed and it shows that the fouling deposit from the chilli sauce is categorized as carbohydrate-based fouling deposits. Activation energy of chilli sauce is 7049.4 J.mole-1 which shows a greater effect of temperature on the viscosity. The hardness, stickiness of fouling deposit and the heat resistance increases as the chilli sauce continuously flows inside the heat exchanger.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Investigation and analysis of short overheat in boiler tube failure in power plant units

    International Nuclear Information System (INIS)

    Boiler tube failure are the main cause of forced outages of power generating units and due to cost, Penalty is very high. Sources and reasons of tube failures are various, but it can be generally categorized by mechanical and corrosion factors with 81% and 19% contributions, respectively. Among the mechanical factors short overheat has the major contribution in water wall and superheater tube, failure. In this paper short overheat mechanism (with appearance and metallurgical features) and its prevention method is over viewed

  3. Parameter Tuning via Genetic Algorithm of Fuzzy Controller for Fire Tube Boiler

    OpenAIRE

    Osama I. Hassanein; Ayman A. Aly; Ahmed A. Abo-Ismail

    2012-01-01

    The optimal use of fuel energy and water in a fire tube boiler is important in achieving economical system operation, precise control system design required to achieve high speed of response with no overshot. Two artificial intelligence techniques, fuzzy control (FLC) and genetic-fuzzy control (GFLC) applied to control both of the water/steam temperature and water level control loops of boiler. The parameters of the FLC are optimized to locating the optimal solutions to meet the required perf...

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

    Energy Technology Data Exchange (ETDEWEB)

    Keiser, J.R.; Taljat, B.; Wang, X.L. [and others

    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.

  5. Researching the Performance of Dual-Chamber Fire-Tube Boiler Furnace

    Directory of Open Access Journals (Sweden)

    Khaustov Sergei

    2015-01-01

    Full Text Available Autonomous heating systems equipped with fire-tube or shell boilers show high effectiveness, consistent performance and great technical parameters. But there is a significant limitation of its thermal productivity due to the complexity of durable large diameter fire-tube bottoms implementation. Optimization of combustion aerodynamics can be the way to expand the fire-tube boilers performance limit. In this case lots of problems connected with reducing emissions of toxic substances, providing of burning stability, local heat stresses and aerodynamic resistances should be solved. To resolve the indicated problems, a modified model of dual-chamber fire-tube boiler furnace is proposed. The performance of suggested flame-tube was simulated using the proven computer-aided engineering software ANSYS Multiphysics. Results display proposed flame tube completely filled with moving medium without stagnant zones. Turbulent vortical combustion is observed even with the straight-through fuel supply. Active flue gas recirculation in suggested dual-chamber furnace reduces emissions of pollutants. Diminution of wall heat fluxes allows boiler operation at lower water treatment costs.

  6. Flue gas dust composition and fouling tendency in recovery boilers; Flygaskans sammansaettning och nedsmutsande tendens i sodapannan

    Energy Technology Data Exchange (ETDEWEB)

    Forssen, Mikael; Backman, Rainer; Wallen, Jonas; Hupa, Mikko [Aabo Akademi (Finland)

    2000-02-01

    In this work eight Swedish black liquors have been characterized for the following properties: Combustability and bed behavior; Dust formation tendency; Fouling tendency of dust; SO{sub 2} formation tendency; and, NO formation tendency. The research was made using; (i) chemical analysis of the samples, (ii) special laboratory scale combustion and pyrolysis tests and (iii) an advanced computer model (Recovery Boiler Chemistry Advisor) for calculating the chemical composition and melting properties of the flue gas dust (fly ash). All tests and analysis were successfully performed and the results were reproducible and reliable. The results were classified for each of the five properties from one to five, and summarised into a table. The liquors showed good or extremely good combustability, also the behavior of the bed was normal or extremely good. None of the liquors had extremely high or low values in their swelling tendency or in their total combustion times. The liquors showed bigger differences in their tendency to form dust. Most of the liquors were 'good' because of the lower than normal tendency to form dust during combustion. Only one of the liquors, liquor B, was rated as 'bad', one of the liquors, liquor E, was rated 'extremely good', in other words liquor B had the highest tendency to form dust whereas liquor E had the lowest tendency to form dust. The advanced computer modelling work gave the composition, and the melting properties for the two dust components, carry-over and the condensed dust. The fouling tendency of the liquors were extremely good (low), the differences were so small that no distinction could be made between the liquors. Compared to earlier studies, the sticky temperature, T{sub 15}, for the eight liquors were extremely high, for both modelling cases when the combustion was assumed to take place either in a 'cold' or in a 'hot' furnace. This is partly explained by the fact that the

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

    Science.gov (United States)

    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.

  8. The Numerical Simulation Application for Fire-Tube Boiler Heating Surface Safety Evaluation

    Directory of Open Access Journals (Sweden)

    Khaustov Sergei A.

    2016-01-01

    Full Text Available The numerical simulation is applied for fire-tube boiler heating surface safety estimation. Thermal processes in an inflatable fire-tube furnace during its emergency operation were simulated using the finite volume method with Euler approximation and the implicit pressure based algorithm. Study results reproduce failures connected with increasing of impasse aerodynamic resistance. The method of these failures prediction is suggested. Simulation has shown that entering the amount of coolant into combustion volume results in burner fan incapability to overcome the impasse resistance of the furnace. The simulation results are visually confirmed during the inspection of emergency boilers.

  9. Estimation of residual life of boiler tubes using steamside oxide scale thickness

    International Nuclear Information System (INIS)

    In thermal power plants, remaining-life-estimation of boiler tubes is required at regular intervals for a safer and a better functionality of boilers. In this paper, a new method is proposed for the residual life estimation of service exposed boiler tubes using Non-Destructive Ultrasonic Oxide scale thickness measurements, average metal temperature and creep master curve. While steady state conduction heat transfer equations are solved to calculate the average metal temperature, creep master curve is generated from short term stress rupture data of rupture life less than 5000 h on a virgin material. In the present study, the residual life of T22 (2.25Cr-1Mo) service exposed Platen Superheater tube is estimated using two master creep curves, i.e. Larson-Miller Parametric (LMP) method of standard ASME T22 creep data and Wilshire approach of short term stress rupture data of T22. As the residual life is calculated from fundamental conduction heat transfer theory and creep rupture data, the proposed method can be applied for different grades of boiler materials. -- Highlights: ► Residual life is calculated from non-destructive oxide scale thickness, creep master curve and average metal temperature. ► A new method is proposed for calculating residual life using above parameters and from conduction heat transfer principles. ► The method can be applied to different boiler grades for estimating residual life and hence the method is generic

  10. Life Management Technique of Thermal Fatigue for SMST Boiler Tube at Different Heating Zone Using Smithy Furnace

    Directory of Open Access Journals (Sweden)

    Shekhar Pal,

    2014-06-01

    Full Text Available This paper highlights on the evaluation of thermal fatigue failure for SMST (Salzgitter Mannesmann strain less boiler tube DMV 304 HCu boiler tube using life management technique by using of smithy furnace. Boiler tubes are highly affected by operating conditions like, high temperature and high pressure. So it needs periodic checking for the purpose of safety and health assessment of the plant. So using this technique we can identify the degradation of tubes at microstructure level, So that one create the current situation of the component and give respective result.

  11. Stress and integrity analysis of steam superheater tubes of a high pressure boiler

    OpenAIRE

    Daniel Leite Cypriano Neves; Jansen Renato de Carvalho Seixas; Ediberto Bastos Tinoco; Adriana da Cunha Rocha; Ibrahim de Cerqueira Abud

    2004-01-01

    Sources that can lead to deterioration of steam superheater tubes of a high pressure boiler were studied by a stress analysis, focused on internal pressure and temperature experienced by the material at real operating conditions. Loss of flame control, internal deposits and unexpected peak charge are factors that generate loads above the design limit of tube materials, which can be subjected to strain, buckling, cracks and finally rupture in service. To evaluate integrity and dependability of...

  12. Parameter Tuning via Genetic Algorithm of Fuzzy Controller for Fire Tube Boiler

    Directory of Open Access Journals (Sweden)

    Osama I. Hassanein

    2012-04-01

    Full Text Available The optimal use of fuel energy and water in a fire tube boiler is important in achieving economical system operation, precise control system design required to achieve high speed of response with no overshot. Two artificial intelligence techniques, fuzzy control (FLC and genetic-fuzzy control (GFLC applied to control both of the water/steam temperature and water level control loops of boiler. The parameters of the FLC are optimized to locating the optimal solutions to meet the required performance objectives using a genetic algorithm. The parameters subject to optimization are the width of the membership functions and scaling factors. The performance of the fire tube boiler that fitted with GFLC has reliable dynamic performance as compared with the system fitted with FLC.

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

    Science.gov (United States)

    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. Aspects of high temperature corrosion of boiler tubes

    Energy Technology Data Exchange (ETDEWEB)

    Spiegel, M.; Bendick, W. [Salzgitter-Mannesmann-Forschung GmbH, Duisburg (Germany)

    2008-07-01

    The development of new boiler steels for power generation has to consider significant creep strength as well as oxidation and corrosion resistance. High temperature corrosion of boiler materials concerns steam oxidation as well as fireside corrosion of parts, in contact with the flue gas. It will be shown that depending on the quality of the fuel, especially chlorine and sulphur are responsible for most of the fireside corrosion problems. Corrosion mechanisms will be presented for flue gas induced corrosion (HCl) and deposit induced corrosion (chlorides and sulfates). Especially for the 700 C technology, deposit induced corrosion issues have to be considered and the mechanisms of corrosion by molten sulfates 'Hot Corrosion' will be explained. Finally, an overview will be given on the selection of suitable materials in order to minimise corrosion relates failures. (orig.)

  15. Overheating failure of superheater suspension tubes of a captive thermal power plant boiler

    International Nuclear Information System (INIS)

    Failure of boiler tubes is the foremost cause of forced boiler outages. One of the predominant failure mechanism of boiler tubes is the stress rupture failure in the form of either short term overheating or long term overheating which are normally encountered in superheater and reheater sections working in the creep range. The strength of the boiler tube depends on the stress level as well on the temperature of exposure in the creep range. An increase in either can reduce the time to rupture. Time at the exposure temperature is an important factor based on which the failures are categorised as either short term or long term. Though there is no established time duration criteria demarcating the short or long term stress rupture failures, depending on the various manifestations on the failed samples, one can categorise the failure. This paper addresses one such stress rupture failure in the superheater section of a captive thermal power plant of a refinery. Multiple failures on the suspension coil of a superheater section was investigated for the cause of failure. Laboratory investigation of the failed sample involved visual inspection, dimensional measurements, chemical analysis of internal deposits and microstructural study. On the basis of these, the failure was attributed to deposition of trisodium phosphate carried over by the feed water into the superheater section resulting in chokage and increase in local operating hoop stresses of the tube. The ultimate failure was thus categorised as long term overheating failure. (author)

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    Sidhu, Buta Singh; Prakash, S.

    2006-03-01

    Boiler tube steels, namely low carbon steel ASTM-SA-210-Grades A1 (GrA1), 1Cr-0.5Mo steel ASTM-SA213-T-11 (T11), and 2.25Cr-1 Mo steel ASTM-SA213-T-22(T22), were used as substrate steels. Ni-22Cr-10Al-1Y powder was sprayed as a bond coat 150 μm thick before a 200 μm final coating of Ni-20Cr was applied Coatings were characterized prior to testing in the environment of a coal fire boiler. The uncoated and coated steels were inserted in the platen superheater zone of a coal fired boiler at around 755°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.

  19. Analysis of Boiler Operational Variables Prior to Tube Leakage Fault by Artificial Intelligent System

    Directory of Open Access Journals (Sweden)

    Al-Kayiem Hussain H.

    2014-07-01

    Full Text Available Steam boilers are considered as a core of any steam power plant. Boilers are subjected to various types of trips leading to shut down of the entire plant. The tube leakage is the worse among the common boiler faults, where the shutdown period lasts for around four to five days. This paper describes the rules of the Artificial Intelligent Systems to diagnosis the boiler variables prior to tube leakage occurrence. An Intelligent system based on Artificial Neural Network was designed and coded in MATLAB environment. The ANN was trained and validated using real site data acquired from coal fired power plant in Malaysia. Ninety three boiler operational variables were identified for the present investigation based on the plant operator experience. Various neural networks topology combinations were investigated. The results showed that the NN with two hidden layers performed better than one hidden layer using Levenberg-Maquardt training algorithm. Moreover, it was noticed that hyperbolic tangent function for input and output nodes performed better than other activation function types.

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

    Science.gov (United States)

    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.

  1. Finite element and experimental analysis for cold tube-bending of a power station boiler

    Institute of Scientific and Technical Information of China (English)

    LAI Yi-nan; YU Hao-nan; LIU Xian-li; YU Yan-min

    2008-01-01

    Combining the computer simulation, theoretical analysis and experiments, this paper studies the process of tube-bending production of a power station boiler. The FEM-numerical simulation system was set up to study the performance features in the process of manufacturing cold tube-bonding, such as ovality, thinning ratio of wall and the equipment driven force. Experiments were carried out in Harbin boiler factory. The para-metric FEM model can simulate the force and quality parameters for tube-bending process and the error is within5%. Experiments have demonstrated that the results achieved by this system are more useful and economical than those obtained through trial-produce method. It greatly reduces the production cost using computer simula-tion than conducting lots of experiments.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Khaustov Sergei A.

    2015-01-01

    Full Text Available 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.

  4. Formation of corrosion products protecting surfaces of the boiler proper tubes from the combustion chamber

    Directory of Open Access Journals (Sweden)

    M. Pietrzyk

    2007-04-01

    Full Text Available Purpose: The aim of this paper is to determine how the oxidation product layer of the steel applied for the radiant tubes should increase if we are going to obtain the lowest possible corrosion losses.Design/methodology/approach: Boiler tubes, made of 13CrMo4-5 steel were subjected to tests. In the boiler BP-1150, the tubes ø 30 x 5 mm are joined by fins and form a membrane shield. According to the maps of tube wall thickness, in the zone of the highest heat load, sectors of the shield were sampled in the places where the tube wall thickness was equal or greater than 4.3 mm, i.e. the minimum calculation thickness, according to the specifications given by the boiler manufacturer. It means that the corrosive loss could be determined as small, in spite of a long operation time (more than 60,000 hours.Findings: The authors have determined structure and chemical and phase compositions of products and deposits forming in the radiant tubes in the regions of low corrosive losses after long-lasting operation (up to 60,000 hours. Then, they discussed a mechanism of formation of a compact layer protecting a steel surface against excessive oxidation under combustion gases.Practical implications: The layer on the tubes with small losses of wall thickness are characterized by the following properties: good compactness, very good adhesion to the metallic base, low amount of sulfur, especially in magnetite, no aggressive components at the phase boundary product – steel, small development of the phase boundary product-steel. Owing to those properties, even presence of sulfur in the products do not reduce their passivation qualities.Originality/value: Determination of the oxidation product layer of the steel applied for the radiant tubes.

  5. Some aspects of metallurgical assessment of boiler tubes-Basic principles and case studies

    International Nuclear Information System (INIS)

    Microstructural changes in boiler tubes during prolong operation at high temperature and pressure decrease load bearing capacity limiting their useful lives. When the load bearing capacity falls below a critical level depending on operating parameters and tube geometry, failure occurs. In order to avoid such failures mainly from the view point of economy and safety, this paper describes some basic principles behind remaining life assessment of service exposed components and also a few case studies related to failure of a reheater tube of 1.25Cr-0.5Mo steel, a carbon steel tube and final superheater tubes of 2.25Cr-1Mo steel and remaining creep life assessment of service exposed but unfailed platen superheater and reheater tubes of 2.25Cr-1Mo steel. Sticking of fly ash particles causing reduction in effective tube wall thickness is responsible for failure of reheater tubes. Decarburised metal containing intergranular cracks at the inner surface of the carbon steel tube exhibiting a brittle window fracture is an indicative of hydrogen embrittlement responsible for this failure. In contrast, final superheater tube showed that the failure took place due to short-term overheating. The influence of prolong service revealed that unfailed reheater tubes exhibit higher tensile properties than that of platen superheater tubes. In contrast both the tubes at 50 MPa meet the minimum creep rupture properties when compared with NRIM data. The remaining creep life of platen superheater tube as estimated at 50 MPa and 570 deg. C (1058 oF) is more than 10 years and that of reheater tube at 50 MPa and 580 deg. C (1076 oF) is 9 years

  6. Early tube leak detection system for steam boiler at KEV power plant

    Directory of Open Access Journals (Sweden)

    Ismail Firas B.

    2016-01-01

    Full Text Available Tube leakage in boilers has been a major contribution to trips which eventually leads to power plant shut downs. Training of network and developing artificial neural network (ANN models are essential in fault detection in critically large systems. This research focusses on the ANN modelling through training and validation of real data acquired from a sub-critical boiler unit. The artificial neural network (ANN was used to develop a compatible model and to evaluate the working properties and behaviour of boiler. The training and validation of real data has been applied using the feed-forward with back-propagation (BP. The right combination of number of neurons, number of hidden layers, training algorithms and training functions was run to achieve the best ANN model with lowest error. The ANN was trained and validated using real site data acquired from a coal fired power plant in Malaysia. The results showed that the Neural Network (NN with one hidden layers performed better than two hidden layer using feed-forward back-propagation network. The outcome from this study give us the best ANN model which eventually allows for early detection of boiler tube leakages, and forecast of a trip before the real shutdown. This will eventually reduce shutdowns in power plants.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Mathematical Model for Predicting Corrosion Rates in Furnace Internal Wall Tubes of The Refinery Boiler

    Directory of Open Access Journals (Sweden)

    Edori, E. S

    2016-08-01

    Full Text Available A model for predicting the corrosion rates in the furnace internal wall tubes of the refinery boiler was resolved, using the first order differential equation derived from the material balance equation of the system. The mathematical model was able to predict the metal loss recorded by ultrasonic thickness scanning technique (UTS, and the results shows an agreement. The results from both the model and UTS shows that in the various tubes of the furnace, internal wall of the refinery boiler were between the same range. The percentage deviation which was calculated to ascertain the acceptability of the model result as compared to that from UTS proved that the model is effective. The inhibitor model result show that corrosion will drastically reduce in the presence of corrosion inhibitors under proper chemical treatment and management. The model developed can be used to monitor furnace internal wall corrosion even when the system is in operation by extrapolating the result to further years.

  9. Fouling propensity of high-phosphorus solid fuels: Predictive criteria and ash deposits characterisation of sunflower hulls with P/Ca-additives in a drop tube furnace

    OpenAIRE

    De Fusco, Lucio; Boucquey, A.; Blondeau, J.; Jeanmart, Hervé; Contino, F

    2016-01-01

    Fouling from the processing of residual biomass fuels in combustion applications is a major concern. This paper discusses the fouling behaviour of sunflower hulls with a high phosphorus (P) content by means of a broad fuel characterisation strategy including advanced predictive indices, the fuel selective leaching, multiple deposition tests in a Drop Tube Furnace (DTF) and deposits analysis with scanning electron microscopy–energy dispersive X-rays spectroscopy (SEM–EDS). First, we summarise ...

  10. EXPERIMENTAL INVESTIGATION OF NICKEL ALUMINIDE (NI3AL) NANOSTRUCTURED COATED ECONOMISER TUBE IN BOILER

    OpenAIRE

    * Gokulakannan A, Karuppasamy K

    2016-01-01

    Thermal Power Stations all over the world are facing the problem of boiler tube leakage frequently. The consequences of which affects the performance of power plant and huge amount of money loss. Hot corrosion and erosion are recognized as serious problems in coal based power generation plants in India. The maximum number of cause of failure in economizer unit is due to flue gas erosion. The corrosion resistant coatings used conventionally are having some limitations like degradation of the c...

  11. Accident Analysis and Processing of Front and Back Tube Plate Cracking and Tube Explosion of a Boiler%对某锅炉前后管板裂纹及爆管的事故分析与处理

    Institute of Scientific and Technical Information of China (English)

    藏秀君

    2014-01-01

    In order to ensure the quality of water treatment of boiler inspection, prevent and reduce the accident due to fouling, corrosion and steam quality deterioration, and promote safety, economy, energy saving, environmental protection of boiler operation, this paper analyzes the situation of without building the complete water treatment management, job responsibilities, operation, and maintenance system and unreal lab technician test index in the operation process of the boiler in a Jilin aviation college. The supervision and inspection of the boiler feed water hardness, YD=6.5mmol/L, dissolved solids 5000mg/L, suspended boiler water alkalinity seriously exceeds the standard, and other indicators do not meet the standard. The school boiler technicians do not seriously implement the requirements of standard GB/T1576-2008"quality"of industrial boiler, which causes the accidents of serious scaling and corrosion of boiler tube explosion. After analysis, this paper proposes the solutions and the treatment schemes.%为了确保锅炉水处理检验工作质量,防止和减少由于结垢、腐蚀及蒸汽质量恶化而造成的事故,促进锅炉运行的安全、经济、节能、环保,本文对吉林某航空院校锅炉,在使用运行过程中没有建立建全水处理管理、岗位职责、运行操作、维护保养等制度及化验员检验指标不真实的状况进行分析。经笔者监督检测了锅炉给水的硬度YD=6.5mmol/L,溶解固形物5000mg/L,锅水碱度、悬浮物严重超标,及其它指标均不符合标准。该校锅炉化验员没有认真执行GB/T1576-2008《工业锅炉水质》标准要求,造成锅炉严重结垢、腐蚀爆管等事故,经分析,提出解决及处理方案。

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

    Science.gov (United States)

    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.

  13. Chemical preventive remedies for steam generators fouling and tube support plate blockages

    International Nuclear Information System (INIS)

    In 2006, EDF identified on several PWR units broached hole blockage on the upper Steam Generator (SG) Tube Support Plates (TSP). TSP blockage often occurs in association with secondary fouling. The units with copper alloys materials are more affected due the applied low pH25oC (9.20) all volatile treatment (AVT). Carbon steels materials are less protected against flow accelerated corrosion (FAC) and therefore more corrosion products enter the SGs through the final feed water (FFW). In parallel of chemical cleanings to remove oxides deposits in SGs, EDF has defined a strategy to improve operating conditions. It mainly relies on the removal of copper alloys materials to implement a high pH AVT (9.60) as a preventive remedy. However for some plants, copper alloys removal is not straightforward due to environmental constraints. EDF must indeed manage the implementation of a biocide treatment needed in closed loop cooling systems (as copper has a bacteriostatic effect on micro-organisms) and more generally must comply with discharge authorisations for chemical conditioning reagents or biocide reagent. An alternative conditioning was tested on the Dampierre 4 unit in 2007/2008 during 6 months to assess if operating at 9.40 was acceptable regarding the impacts on copper alloys materials. The perspective would be to implement it in the units where no biocide treatment can be applied on a short term. In parallel, other chemical conditionings or additives will be implemented or tested. First of all, EDF will carry out a trial test with APA in order to assess its efficiency on the removal of oxides deposits through SG blowdown. On the other hand, AVT with high pH ethanolamine (ETA) will be implemented as an alternative of ammonia and morpholine conditioning on some chosen plants. Ethanolamine is selected as a way to mitigate FAC kinetics in two-phase flow areas (reheaters or moisture heater separator) or to limit liquid releases. This paper provides the lessons of the

  14. Creep properties of electric resistance welded boiler tubes under internal pressure

    International Nuclear Information System (INIS)

    Creep rupture tests on electric resistance welded (ERW) tubular specimens of carbon steel and 1% Cr-0.5% Mo steel and burst tests on thickness-deviated tubular specimens of carbon steel are described. Also, changes of structures and mechanical properties of 1% Cr-0.5% Mo steel tubes after exposure to 5500C for up to 10,000 hours under a tensile hoop stress of 108 MPa are described. The creep rupture properties of ERW boiler tubes were proved to be quite comparable to those of seamless tubes, and the slightest deviation in wall thickness was shown to affect the internal pressure rupture behavior. Changes of structures at welded portion of ERW 1% Cr-0.5% Mo steel tubes were as same as those of base metal

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Banovic, S.W.; DuPont, J.N.; Marder, A.R. [Lehigh Univ., Bethlehem, PA (United States). Energy Research Center

    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.

  17. On the influence of chlorides and sulphureous compounds on the corrosion of superheater tubes in boilers with special consideration on kraft recovery boilers

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, Fredrik [AaF-IPK AB, Stockholm (Sweden)

    1999-03-01

    This report reviews the thermochemistry of the most relevant corrosion reactions and mechanisms with chloride especially considering the kraft pulp mill recovery boiler. The flue gas side corrosion of superheater tubes is governed by the fuel constituents, and by the carryover particles and the gaseous impurities accompanying the flue gases and the local chemical conditions they cause on the superheater tube surface. A study made on coal-fired boilers in Germany has been interpreted so that the protective ability of the oxide layer on the tube surface of a superheater tube is limited, which causes a close to linear time dependence of the material loss due to corrosion. The thermochemistry of the reactions of the protective oxide layer itself with the components of the deposited carryover and the flue gas sulphur components seems thus to govern the mechanism of the corrosion. The corrosion in the recovery boiler is concluded to be more dependant on this combined action of carry-over and sulphureous oxides, so the presence of chlorides in the flue gases only influences the melting range properties of the sulphate deposits, but seems to exert less influence on the chemical reactions which attack the oxides of the passive layer. The thermochemistry also explains the formation of a sulphide layer often found between the deposits and the surface of the tube metal on superheater tubes as a result of reaction with sulpureous oxides from the flue gas and carbon in the carryover. The factors which in practice limit the superheater corrosion in the recovery boiler are interpreted as both material and process dependent. The main limiting factor for the steam temperature is still the melting range of the sulphate deposit. There seems thus to be little hope for the aim to raise the steam temperature of the kraft recovery boiler above the range which is already achievable with the presently available composite tubes 22 refs, 10 figs

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

    Science.gov (United States)

    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.

  19. Design of an ion transport membrane reactor for application in fire tube boilers

    International Nuclear Information System (INIS)

    A design of an ITM (ion transport membranes) reactor is introduced in a two-pass fire tube boiler furnace to produce steam for power generation toward the ZEPP (zero emission power plant) applications. Oxygen separation, combustion and heat exchange occur in the first pass containing the multiple-units ITM reactor. In the second pass, heat exchange between the combustion gases and the surrounding water at 485 K (Psat = 20 bar) occurs mainly by convection. The emphasis is to extract sufficient oxygen for combustion while maintaining the reactor size as compact as possible. Based on a required power in the range of 5–8 MWe, the fuel and gases flow rates were calculated. Accordingly, the channel width was determined to maximize oxygen permeation flux and keep the viscous pressure drop within a safe range for fixed reactor length of 1.8 m. Three-dimensional simulations were conducted for both counter and co-current flow configurations. Counter-current flow configuration proved its suitability in fire tube boilers for steam generation over the co-current flow configuration. The resultant reactor consists of 12,500 ITM units with a height of 5 m, membrane surface area of 2700 m2 and a total volume of 45.45 m3. - Highlights: • A novel two-path fire tube boiler design is presented utilizing ITMs (ion transport membranes). • A new multi-unit ITM reactor design for boiler furnace substitution is presented. • Flow rates have been optimized for maximum oxygen flux and power generation. • Counter-current flow configuration is much more efficient than co-current flow. • Total number of ITM units was calculated to produce power of 5:8 MWe

  20. An advanced maintenance advisory and surveillance system for boiler tubes - AMASS

    Energy Technology Data Exchange (ETDEWEB)

    Tomkins, A.B. [ERA Technology Ltd, Leatherhead (United Kingdom)

    1998-12-31

    In a recently completed European collaborative project, the aim was to address the issue of boiler tube failures and thereby plant availability. The reduction of forced outages due to component failures and the reduction of planned outages for preventative maintenance can both contribute in this respect. It has been possible to assess tube degradation due to erosion, corrosion and overheating through the use of on-line techniques (thin layer activation, corrosion probes and novel temperature sensors) and off-line techniques (cold air velocity measurements, laser shearography and measurements of steam side oxide) which have been developed in the project. These techniques have been demonstrated on an oil fired boiler in Portugal and a coal fired unit in Spain. The output from the monitoring techniques has been integrated in the AMASS maintenance advisory and surveillance system. This is a computerised system comprising a spatial database with add-on tools designed to assess data from individual monitors and to provide the user with information on tube life utilisation rates and the probability of tube failure occurring. A description of the monitoring techniques will be described along with some of the results of demonstrating them in the field. Also an overview of the computerized system and the way in which it works will be given along with examples of how it can be used to assist with preventative maintenance and to help avoid unplanned outages. (orig.) 10 refs.

  1. On-line monitoring and control of furnace wall corrosion in pf-fired boilers

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, D.M.; Robbins, B.J.; Sikka, P.; Seaman, M. [Rowan Technologies Ltd., Manchester (United Kingdom)

    2004-05-15

    Corrosion, fouling and sometimes failure of heat exchanger tubing that makes up the boiler walls is a major obstacle to minimising boiler downtime. Rowan Technologies Ltd., has been developing corrosion scanners to enable the condition of these heat exchanger tubes to be assessed online. These scanners are able to monitor fireside corrosion over entire boiler walls and whilst the boiler is operational. This paper describes how the scanner systems can be used to monitor this corrosion and how the corrosion can be subsequently controlled. 8 refs., 9 figs.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  5. FAILURE ANALYSIS IN TUBING OF AIR PREHEATER OF BOILER FROM A SUGARCANE MILL

    Directory of Open Access Journals (Sweden)

    Joner Oliveira Alves

    2014-10-01

    Full Text Available The increased demand for energy from sugarcane bagasse has made the sugar and alcohol mills search alternatives to reduce maintenance of the boilers, releasing more time to the production. The stainless steel use has become one of the main tools for such reduction. However, specification errors can lead to premature failures. This work reports the factors that led tubes of AISI 409 stainless steel fail after half season when applied in a air preheater of boiler from a sugarcane mill. In such application, the AISI 304 lasts about 15 seasons and the carbon steel about 3. A tube sent by the sugar mill was characterized by wet chemical analysis, optical microscopy and EDS. Results indicated chloride formation on the internal walls of the tube, which combined with the environment, accelerated the corrosion process. The carbon steel showed high lifetime due to a 70% higher thickness. Due to the work condictions is recommended the use of stainless steels with higher corrosion resistance, such as the traditional AISI 304 or the ferritic AISI 444, the last presents better thermal exchange.

  6. INTRODUCTION TO INCONEL ALLOY 740: AN ALLOY DESIGNED FOR SUPERHEATER TUBING IN COAL-FIRED ULTRA SUPERCRITICAL BOILERS

    Institute of Scientific and Technical Information of China (English)

    S.J. Patel

    2005-01-01

    Chinese utilities as well as those worldwide are facingincreased demand for additional electric-ity, reduced plant emissions and greater efficiency.To meet this challenge willrequire increas-ing boiler temperature,pressure and coal ashcorrosion resistance of the materials of boiler construction of future coal-fired boilers. A new nickel-based tube alloy, INCONELRalloy 740,is described aiming at meeting this challenge. Emphasis will be on describing the alloy s mechanical properties, coal-ash and steam corrosion resistance.Microstructural stability as a function of temperature and time is addressed as well as some of the early methodology employed to arrive at the current chemical composition.

  7. The creep life of superheater and reheater tubes under varying pressure conditions in operational boilers

    International Nuclear Information System (INIS)

    The first of each manufacturer's 500 MW boilers supplied to the CEGB (Central Electricity Generating Board) have been subjected to an extensive programme of tests for performance optimization and safe operation. Around 250 thermocouples on superheater and reheater tubes have in each case been monitored as part of the exercise. The readings are corrected and used to compute creep rupture damage based on internationally agreed stress rupture data and a simple cumulative damage concept. Comparison of the design creep rupture life and the cumulative life consumed has in several applications been invaluable in influencing operating procedures and arranging tube modifications or replacements, so that loss of generation by creep rupture failure is minimized. (author)

  8. Stress and integrity analysis of steam superheater tubes of a high pressure boiler

    Energy Technology Data Exchange (ETDEWEB)

    Neves, Daniel Leite Cypriano; Seixas, Jansen Renato de Carvalho [PETROBRAS, Duque de Caxias, RJ (Brazil). Refinaria Duque de Caxias (REDUC). Mantencao Industrial]. E-mail: dcypriano@petrobras.com.br; Tinoco, Ediberto Bastos [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES). Engenharia de Equipamento Basico; Rocha, Adriana da Cunha; Abud, Ibrahim de Cerqueira [Instituto Nacional de Tecnologia (INT), Rio de Janeiro, RJ (Brazil). Lab. de Metalografia e de Dureza

    2004-03-01

    Sources that can lead to deterioration of steam superheater tubes of a high pressure boiler were studied by a stress analysis, focused on internal pressure and temperature experienced by the material at real operating conditions. Loss of flame control, internal deposits and unexpected peak charge are factors that generate loads above the design limit of tube materials, which can be subjected to strain, buckling, cracks and finally rupture in service. To evaluate integrity and dependability of these components, the microstructure of selected samples along the superheater was studied by optical microscopy. Associated with this analysis, dimensional inspection, nondestructive testing, hardness measurement and deposit examination were made to determine the resultant material condition after twenty three years of operation. (author)

  9. Stress and integrity analysis of steam superheater tubes of a high pressure boiler

    Directory of Open Access Journals (Sweden)

    Neves Daniel Leite Cypriano

    2004-01-01

    Full Text Available Sources that can lead to deterioration of steam superheater tubes of a high pressure boiler were studied by a stress analysis, focused on internal pressure and temperature experienced by the material at real operating conditions. Loss of flame control, internal deposits and unexpected peak charge are factors that generate loads above the design limit of tube materials, which can be subjected to strain, buckling, cracks and finally rupture in service. To evaluate integrity and dependability of these components, the microstructure of selected samples along the superheater was studied by optical microscopy. Associated with this analysis, dimensional inspection, nondestructive testing, hardness measurement and deposit examination were made to determine the resultant material condition after twenty three years of operation.

  10. Thermal shocks in solar boiler tubes and mechanical tolerance to heating velocity

    International Nuclear Information System (INIS)

    The boiler circular cross-section tubes are cooled by an internal flow and are subjected to a non uniform heat flux around their outer circumference that changes very rapidly with time. Thus thermal shocks can develop in the thickness of tube walls and may cause brittle fracture or fatigue damage. We solve the corresponding thermoelastic problem. The determination of temperature distribution through the wall thickness requires the solution of one-dimensional transient heat equation obtained by performing a Fourier expansion in the angular variable. For each harmonic, Galerkin's method with respect to the radial coordinate together with a finite difference scheme with respect to time permit to completely discretize the associated equation. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. The Hot Corrosion Performance of NiCr-Cr3 C2 Cermet Coating to Boiler Tube

    Institute of Scientific and Technical Information of China (English)

    DINGZhang-xiong; TUGuo-fu

    2004-01-01

    Three kinds of NiCr-Cr3 C2 cermet coatings were designed and deposited by the subsonic velocity flame spraying, and their performances of hot corrosion performance were evaluated in comt)arison with 102G,20G boiler tube steel, FeCrAl, NiCrTi, Ni5OCr and NiCrAIMoFe-Cr3 C2 coatings, which are widely used at present for protection of boiler tubes. Meanwhile, the influence of sealer on the hot corrosion resistance of warious coatings and the mechanisms of coating corrosion were explored.

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

    Science.gov (United States)

    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.

  14. Remaining Life Analysis of Boiler Tubes on Behalf of Hoop Stresses Produced During Operation of Power Plant

    Directory of Open Access Journals (Sweden)

    Mohd. Zeeshan Gauri

    2014-07-01

    Full Text Available Boiler tube material plays an important role in efficient power generation from a fossil fuel power plant. In order to meet out the gap between fluids to increase heat available per unit mass flow of steam. Waste heat utilization phenomenon is a big challenge on fossil fuel power plants as after use of high grade coal in thermal power plants the efficiency of power plants is not at the level of required value. Clean and efficient power generation with economical aspects is the basic need of growing power generation plants to justify the quality of power and clean power generation. Life analysis technique to calculate remaining life of boiler tubes at critical zones of high temperature requires much attention and is an important hypothesis in research field. Generation of repetitive and fluctuating stress during flow of high temperature and pressure fluid require proper attention on the methodology to be used to calculate the efficiency of system and absorption efficiency of tube material. In this paper complete mathematical analysis of boiler tubes is conducted for calculation of remaining life of boiler tubes, Hoop stress values are calculated and used with mathematical tool to calculate the efficiency. Hoop stress based calculation of efficiency is more reliable and may give more accurate and practical aspects based results.

  15. Thermal-hydraulic modeling of the steady-state operating conditions of a fire-tube boiler

    Directory of Open Access Journals (Sweden)

    Rahmani Ahmed

    2009-01-01

    Full Text Available In this work, we are interested to simulate the thermal-hydraulic behavior of three-pass type fire-tube boiler. The plant is designed to produce 4.5 tons per hour of saturated steam at 8 bar destined principally for heating applications. A calculation program is developed in order to simulate the boiler operation under several steady-state operating conditions. This program is based upon heat transfer laws between hot gases and the fire-tube internal walls. In the boiler combustion chamber, the heat transfer has been simulated using the well-stirred furnace model. In the convection section, heat balance has been carried out to estimate the heat exchanges between the hot gases and the tube banks. The obtained results are compared to the steady-state operating data of the considered plant. A comparative analysis shows that the calculation results are in good agreement with the boiler operating data. Furthermore, a sensitivity study has been carried out to assess the effects of input parameters, namely the fuel flow rate, air excess, ambient temperature, and operating pressure, upon the boiler thermal performances.

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

    Science.gov (United States)

    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.

  17. Study of Microstructure Degradation of Boiler Tubes Due To Creep for Remaining Life Analysis

    Directory of Open Access Journals (Sweden)

    Kavita Sankhala

    2014-07-01

    Full Text Available In the current scenario of power shortage in India, the main objective is to ensure availability of power plant and increasing its reliability. During assessment ,testing and inspection a simple question has to be asked again and again‖ How long the particular power plants can be operated safely and cost-effectively with satisfying increased requirements and operational availability with reduced pollutant emissions, even after their designed life. So to answer this important question regarding the operational capability of the existing plant the remaining life analysis (RLA has to be done. The condition of the plant equipments can be assessed only by way of a RLA methodology. On the basis of RLA proper decision can be made about the plants safety and availability. There are many methods to carry out the RLA of the critical components out of which ―microstructure study‖ is a method. In this paper we have tried to outline the RLA procedures and review the various damage mechanisms based on microstructure study. It is also presents the microstructure changes and properties of 106720 service hour exposed boiler tube in a 120 MW boiler of a thermal power plant.

  18. Particle Image Velocimetry Measurment of Flow Across Tube Bundle in Waste Heat Boiler

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In the present paper the experimental investigations of flow across staggered tube bundles in waste heat boiler are conducted by mans of PIV (Particle Image Velocimetry)system,Flow visualization and velocity distribution of the wake between different cylinders are measured in detail.It is concluded that there are still Von Karman vortices in the wake and the phenomenas of vortex shedding,pairing,merging are observed in the flow.The Von Karman vortices can't fully developed because of the existence of the downstream cylinder.There is interaction between main streams and vortices,and the development of the vortex is enhanced by this interaction.Meanwhile some statistical results are performed.The distribution of correlated variables of the velocity fluctuations μ′μ′,μ′ν′,ν′ν′ and the space correlation coefficients are obtained.

  19. Microstructural degradation of boiler tube steels under long term exposure to high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Salonen, J.; Auerkari, P. [VTT Manufacturing Technology, Espoo (Finland)

    1996-12-31

    Thermal microstructural degradation was investigated by isothermal annealing of samples from boiler tube steels St 35.8, 15 Mo 3, 13 CrMo 44, 10 CrMo 9 10 and X20 CrMoV 12 1 in the temperature range 600-780 deg C for up to 2 000 h. Optical and scanning electron microscopy and hardness testing were used for characterising the micro structural changes and their time-temperature dependence. The results suggest a simple and consistent time-temperature dependence for all investigated materials, expected to apply also to long term service beyond the annealing time range of the present work. This would allow assessment of the in-service thermal exposure from the observed microstructure. A collection of micro graphs has been prepared for this purpose, to aid in classifying and evaluating the observed microstructural state in terms of isothermal exposure to high temperature. (orig.) (6 refs.)

  20. Application of a new thermoelastic thick shell theory to solar boiler tubes

    International Nuclear Information System (INIS)

    The classical thin shell theory relies on Kirchhoff's hypotheses which notably lead one to neglect normal stresses in the 'thickness direction', shearing stresses on surfaces parallel to the mean surface, warping and extension of fibers normal to the same surface. As is well known, the thermoelastic constitutive equations contradict these assumptions, which are no longer acceptable when the shell is not 'very thin' and when the thermal gradient through the thickness becomes noticeable. The thick shell theory proposed here was initially meant to describe the behavior of solar boiler tubes, but it is also applicable to piping elements encountered in most energy conversion systems, such as fossil-fired power plants, nuclear reactors, etc. For the sake of simplicity, the presentation is restricted to the study of a long tube subjected to an intense heat flux on one side; this tube carries a working fluid and the temperature distribution in the metal is not axisymmetric. By generalizing the asymptotic expansion theory of Reiss to the thermoelastic case, it is shown that higher order theory immediately following the classical thin shell approach should be based upon a displacement field whose radial component is a second order polynomial in the thickness coordinate z, whereas the tangential component is a third order polynomial in the same coordinate; the coefficients of these two polynomials are the generalized displacements of the theory. Then a 'generalized' Kirchhoff hypothesis is used, which consists in requiring the shearing stresses or deformations to vanish on the inner and outer tube surfaces only. This allows one to express two of the generalized displacements in terms of the others. The so-constructed displacement distribution is sufficiently general to account for warping and extension of fibers normal to the mean surface as well as shearing on surfaces z = constant; these effects are usually neglected. (orig.)

  1. Research on the Hydrodynamic Characteristics and Metal Temperature Distribution in Spiral tube Water Wall of an Ultra Supercritical Boiler

    Science.gov (United States)

    Zhang, Weijing; Yang, Dong; Pan, Jie; Zhou, Xu

    2010-03-01

    On the basis of a 350 MW supercritical pressure OTSC boiler, established the mathematical model for the circulation loop flow and grid pressure in a complex flow network system, and an iteration method was used to solve the nonlinear equations. The water wall flow distribution and temperature profile of the boiler were computed. The results show that the flow difference and heat difference are small in spiral tube water wall at BMCR, 75%BMCR load and 30%BMCR load. The metal temperatures are all in the range of allowable range, and the operation of boil is safe and reliable.

  2. Boilers, evaporators, and condensers

    International Nuclear Information System (INIS)

    This book reports on the boilers, evaporators and condensers that are used in power plants including nuclear power plants. Topics included are forced convection for single-phase side heat exchangers, heat exchanger fouling, industrial heat exchanger design, fossil-fuel-fired boilers, once through boilers, thermodynamic designs of fossil fuel-first boilers, evaporators and condensers in refrigeration and air conditioning systems (with respect to reducing CFC's) and nuclear steam generators

  3. Needs-driven soot blowing in waste boilers; Behovsstyrd sotblaasning i avfallspannor

    Energy Technology Data Exchange (ETDEWEB)

    Niklasson, Fredrik; Davidsson, Kent

    2009-09-15

    The increased use of alternative and waste fuels has resulted in an increased number of plants having trouble with fouling and corrosion on boiler banks and superheater tubes. Frequent sootblowing will keep the surfaces relatively clean, but on the other hand, it may erode the tube material. An intelligent sootblowing system will initiate sootblowings on individual tube banks only when needed for that specific tube bank. Such a system depends on the detection of the degree of fouling of specific tube banks. In this project, the conditions for an intelligent sootblowing system at the waste fired boilers in Boraas are investigated from measured flows, temperatures and pressure drop. New thermocouples at the water tubes between the banks of the economiser have been installed and connected to the control and monitoring system of the boiler. From measured temperatures and flows, heat transfer coefficients are calculated and used to detect the fouling on the heat exchangers. A pressure transducer has been altered to measure the pressure over the boiler bank. At the superheaters, the measurements show a significant improvement of the heat transfer coefficients immediately following sootblowing. Thereafter, the heat transfer coefficients decline more slowly, almost linearly. The measurements indicate that the fouling rate is almost same for the two superheaters and do not motivate individual sootblowing sequences of the two superheaters. The pressure drop over the boiler bank was found too insensitive a measure to be used as an indicator for an intelligent sootblowing system, at least in this specific boiler. In the economiser, the decline of calculated heat transfer coefficients showed a relative rate of fouling on individual tube banks. The results show that the fouling rate is significantly higher in the top tube banks, which comes first in the direction of the flue gas, compared to downstream banks. Experiments by sootblowing the top tube bank more frequently than the

  4. Numerical Investigation of Simultaneously Deposition and Re-Entrainment Fouling Processes in Corrugated Tubes by Coupling CFD and DEM

    DEFF Research Database (Denmark)

    Hærvig, Jakob; Condra, Thomas Joseph; Sørensen, Kim

    The deposition of particulate fouling on flue gas heat exchanger surfaces results in decreased heat transfer. Even though an increasingly amount of work is done on the design of clean heat exchanger surfaces, the effect of fouling remains a challenge. As some heat exchanger designs are more prone...... Computational Fluid Dynamics (CFD) software OpenFOAM is coupled to the Discrete Element Method (DEM) software LIGGGHTS using the coupling software CFDEM. A four-way coupling is used to model fluid-particle and particle-particle interactions and thereby allowing for a particle fouling layer to build up along...

  5. Remaining Life Analysis of Boiler Tubes on Behalf of Hoop Stresses Produced During Operation of Power Plant

    OpenAIRE

    Mohd. Zeeshan Gauri; Kavita Sankhala

    2014-01-01

    Boiler tube material plays an important role in efficient power generation from a fossil fuel power plant. In order to meet out the gap between fluids to increase heat available per unit mass flow of steam. Waste heat utilization phenomenon is a big challenge on fossil fuel power plants as after use of high grade coal in thermal power plants the efficiency of power plants is not at the level of required value. Clean and efficient power generation with economical aspects is the...

  6. High-Temperature Corrosion of Protective Coatings for Boiler Tubes in Thermal Power Plants

    Institute of Scientific and Technical Information of China (English)

    XU Lianyong; JING Hongyang; HUO Lixing

    2005-01-01

    High-temperature corrosion is a serious problem for the water-wall tubes of boilers used in thermal power plants. Oxidation, sulfidation and molten salt corrosion are main corrosion ways.Thereinto, the most severe corrosion occurs in molten salt corrosion environment. Materials rich in oxides formers, such as chromium and aluminum, are needed to resist corrosion in high-temperature and corrosive environment, but processability of such bulk alloys is very limited. High velocity electric arc spraying (HVAS) technology is adopted to produce coatings with high corrosion resistance. By comparison, NiCr (Ni-45Cr-4Ti) is recommended as a promising alloy coating for the water-wall tubes, which can even resist molten salt corrosion attack. In the study of corrosion mechanism, the modern material analysis methods, such as scanning electron microscopy (SEM), X-ray diffractometry (XRD) and energy dispersive spectrometry (EDS), are used. It is found that the corrosion resistances of NiCr and FeCrAI coatings are much better than that of 20g steel, that the NiCr coatings have the best anti-corrosion properties, and that the NiCr coatings have slightly lower pores than FeCrAI coatings.It is testified that corrosion resistance of coatings is mainly determined by chromium content, and the microstructure of a coating is as important as the chemical composition of the material. In addition, the fracture mechanisms of coatings in the cycle of heating and cooling are put forward. The difference of the thermal physical properties between coatings and base metals results in the thermal stress inside the coatings. Consequently, the coatings spall from the base metal.

  7. Development of an electrochemistry-based corrosion sensor to monitor corrosion of boiler tubes, pipes, and painted structures

    Science.gov (United States)

    Davis, Guy D.; Dacres, C. M.; Shook, M. B.

    1998-03-01

    An electrochemical impedance spectroscopy (EIS)-based in-situ corrosion sensor has been adapted and evaluated for use with steel heat exchanger tubes in boilers, coated buried steel pipes, and painted steel structures. An excellent correlation was obtained between the algorithm of the ratio of the breakpoint frequencies, as measured by the sensor, and corrosion rate for the boiler tubes. Use of this sensor and appropriate electronics would allow the corrosion of the boiler tubes to be monitored in real time and the inhibitor concentration automatically controlled to prevent excessive corrosion. The EIS sensor is also sensitive to the quality of coating of a buried steel pipe with and without the application of cathodic protection. Similar results were obtained from a sensor attached to the pipe and from a separate electrode driven into the soil. A hand-held version of the EIS in-situ sensor is suitable for inspecting painted metal structures, such as storage tanks and locks and dams, under ambient, service conditions. An excellent correlation was obtained between the sensor measurements, and the amount of corrosion on test panels immersed for up to 28 years.

  8. Erosion in Steam General Tubes in Boiler and ID Fans in Coal Fired FBC Power Plant

    Directory of Open Access Journals (Sweden)

    Shaheen Aziz

    2012-01-01

    Full Text Available The FBC (Fluidized Bed Combustion is a technique used to make solid particles behave like fluid and grow very fast for the power generation using low grade coal. Due to its merits, first time this technology has been introduced in Pakistan by installing 3x50 MW power plants at Khanote. Fluidized beds have long been used for the combustion of low-quality, difficult fuels and have become a rapidly developing technology for the clean burning of coal. The FBC Power Plant at Khanote has been facing operational and technical problems, resulting frequently shut down of generation units, consequently facing heavy financial losses. This study reveals that due to the presence of high percentage of silica in the lime stone that are further distributed in the bottom ash, fly ash and re-injection material, the generation tubes in the boiler and wings/blades of ID (Induced Draft fans were eroded. In addition, filter bags were also ruptured; resulting frequent shut down of power plant units.

  9. The Boiler Tube Wall Thickness Quantitative Evaluation Fusing the Magnetic and Ultrasonic Technique

    Institute of Scientific and Technical Information of China (English)

    SONG Xiaochun; HUANG Songling; ZHAO Daxing

    2006-01-01

    Wall thickness is always a key index for boiler tube inspection in power plant, in order to improve the inspection efficiency and accuracy, a new method fusing the magnetic and ultrasonic technique was proposed. The magnetic technique was used to do full inspection and locate the flaws, and the ultrasonic was employed to implement further quantitative inspection accurately. After comparing the precision of the polynomial, exponential and logarithmic function, the polynomial model was selected to fit the relations between the wall thickness and the peak value of magnetic signals, and the data measured by ultrasonic thickness meter was used to calibrate the model parameters online, the defect depth can be sized quickly. The experimental results demonstrate that the model used in this system has better accuracy than the statistics relation model clearly, and it is also suitable for defect evaluation real-time. Moreover, it is unnecessary to have much more experimental data for the curve fitting technology, so it has better practicability than the other methods.

  10. Simulation of heat transfer in combustion chamber waterwall tubes of supercritical steam boilers

    Directory of Open Access Journals (Sweden)

    Grądziel Sławomir

    2016-06-01

    Full Text Available The paper presents the results of numerical computations performed for the furnace chamber waterwalls of a supercritical boiler with a steam output of 2400 × 103 kg/h. A model of distributed parameters is proposed for the waterwall operation simulation. It is based on the solution of equations describing the mass, momentum and energy conservation laws. The aim of the calculations was to determine the distribution of enthalpy, mass flow and fluid pressure in tubes. The balance equations can be brought to a form where on the left-hand side space derivatives, and on the right-hand side – time derivatives are obtained. The time derivatives on the right-hand side were replaced with backward difference quotients. This system of ordinary differential equations was solved using the Runge-Kutta method. The calculation also takes account of the variable thermal load of the chamber along its height. This thermal load distribution is known from the calculations of the heat exchange in the combustion chamber. The calculations were carried out with the zone method.

  11. Diagnosis of Heat Exchanger Tube Failure in Fossil Fuel Boilers Through Estimation of Steady State Operating Conditions

    International Nuclear Information System (INIS)

    Estimation of operating conditions for fossil fuel boiler heat exchangers is often required due to changes in working conditions, design modifications and especially for monitoring performance and failure diagnosis. Regular heat exchangers in fossil fuel boilers are composed of tube banks through which water or steam flow, while hot combustion (flue) gases flow outside the tubes. This work presents a top-down approach to operating conditions estimation based on field measurements. An example for a 350 MW unit superheater is thoroughly discussed. Integral calculations based on measurements for all unit heat exchangers (reheaters, superheaters) were performed first. Based on these calculations a scheme of integral conservation equations (lumped parameter) was then formulated at the single tube level. Steady state temperatures of superheater tube walls were obtained as a main output, and were compared to the maximum allowable operating temperatures of the tubes material. A combined lumped parameter - CFD (Computational Fluid Dynamics, FLUENT code) approach constitutes an efficient tool in certain cases. A brief report of such a case is given for another unit superheater. We conclude that steady state evaluations based on both integral and detailed simulations are a valuable monitoring and diagnosis tool for the power generation industry

  12. Development of Square Coal Tube in Boiler%方型锅炉落煤筒的研制

    Institute of Scientific and Technical Information of China (English)

    高平; 王婵; 郭在在; 付利涛; 兰兰; 邸建辉; 闫志飞; 田迎春; 郭永亮

    2014-01-01

    Aimed at the reasons for the early deformation in service and cracking failure of the welding-manufactured square tubes in coal boiler,a lost foam casting process scheme for the square tubes in coal boiler was put forward,and some measures were adopted,such as designing a "well" shape deformation brace,increasing casting chamfering radius,adjusting chemical composition of the material,and so on.The production process for the square tubes in coal boiler were introduced,including lost foam casting process,melting and pouring process,model making and coating process,and model packing process.Practice proves that the service life of the cast square tubes is 1.6 times of welding tubes,which effectively improve the efficiency of transporting coal and the enterprise economic benefit.%针对焊接制造锅炉落煤筒服役早期出现变形和开裂失效的原因,提出了消失模铸造落煤筒的方案,并采取了设计“井”形防变形拉筋,加大铸件铸造倒角半径,调整优化材料的化学成分等措施.同时介绍了消失模铸造落煤筒的熔炼、浇注、模型制作、涂料涂刷和模型装箱等工艺.实践证明,研制的落煤筒使用寿命是焊接制造的1.6倍,有效地提高输煤效率和企业的经济效益.

  13. Analisa Efisiensi Water Tube Boiler Berbahan Bakar Fiber, Cangkang Sawit dan Kulit Kayu Menggunakan Metode Langsung

    OpenAIRE

    Gaol, Dosma Putra Lumban

    2016-01-01

    Some of the factors that affect the efficiency of the boiler is a superheater pressure, water feed temperature, steam temperature, the amount of steam produced, the amount of fuel consumption and calorific value fuel combustion. Steamtab chemicallogic use companion software to calculate the value of enthalpy. The aim of this study is to get relations variations in pressure superheater with boiler efficiency, the relationship of variation of temperature feed water to the boiler efficiency, the...

  14. Factor Analysis of Boiler Flag Control Tube Corner Tube Explosive Accident%锅炉旗面管角管爆管事故原因分析

    Institute of Scientific and Technical Information of China (English)

    阿迪力江·依米提

    2011-01-01

    通过分析DZL6-1.25-AⅡ型角管式链条炉排燃煤蒸汽锅炉水冷壁旗面管角管爆管事故产生的原因,从设计和制造以及运行的角度提出了相应的预防改进措施,说明了蒸汽锅炉运行过程中的注意事项.%Through the analysis of explosive tube accident on DZ boiler water cooling wall, flag control tube, and corner tube, the prevention measure were proposed and the cautions must be taken for safe operation.

  15. CAUSE FOR LEAKAGE FROM 200 MW BOILER TUBE%锅炉管腐蚀泄漏原因分析

    Institute of Scientific and Technical Information of China (English)

    姜锡瑞; 罗兆红

    2001-01-01

    Presents the identification of cause for leakage from 200 MW boiler tube by testing for mechanical property and chemical composition, analysis of metallographical organism and corrosion products and testing for electrode potential and polarization curve of boiler tube material,and points out alkaline corrosion occurs during boiler operation and shutdown when oxygen dissolves into water and Fe3O4 Fe2O3 and corrosion products lead to condensation of alkali at high temperature.%通过对锅炉管材的机械性能、化学成分测定和对金相组织、腐蚀产物的分析及电极电位、极化曲线的测定,找出了锅炉管坑孔腐蚀原因,是由于在锅炉工作和停运时氧溶入使Fe3O4氧化成Fe2O3和在高温条件腐蚀产物下形成碱浓缩导致碱腐蚀.

  16. Weldability of high strength Ni-based alloy USC141 as boiler tube for 700 C USC plant

    Energy Technology Data Exchange (ETDEWEB)

    Bao, G.; Sato, T. [Babcock-Hitachi K.K. Kure-shi, Hiroshima-ken (Japan); Imano, S.; Sato, J. [Hitachi, Ltd. Hitachi-shi, Ibaraki-ken (Japan); Uehara, T.; Toji, A. [Hitachi Metals, Ltd. Yasugi-shi, Shimane-ken (Japan)

    2007-07-01

    Recently the increase of steam temperature and pressure of power plant is required to enhance the thermal efficiency and reduce the CO{sub 2} emission. For the application to advanced USC (Ultra Super Critical) boiler with steam temperature around 700 C, the application of Ni-based alloy such as Alloy617 will be necessary. A new Ni-based alloy USC141 (20Cr-10Mo-2Ti-Al-bal.Ni) with excellent creep rupture strength and low thermal expansion has been developed by Hitachi Ltd. and Hitachi Metals Ltd. as the candidate material for 700 C USC turbine components. In present work, to investigate the possibility for boiler tube application of USC141, its weldability and high temperature strength properties were experimentally examined. The tested material as solution-treated condition shows higher creep rupture strength than that of Alloy617. GTAW (Gas Tungsten Arc Welding) trials of tubular specimen using NIMONIC263 filler wire were conducted successfully and the creep rupture strength of weld joint was as similar as that of parent metal. Therefore it is considered that USC141 has a promising potential as boiler tube candidate for 700 C class USC power plant. (orig.)

  17. Thermal design of horizontal tube boilers. Numerical and experimental investigation; Modelisation thermique de bouilleurs a tubes horizontaux. Etude numerique et validation experimentale

    Energy Technology Data Exchange (ETDEWEB)

    Roser, R.

    1999-11-26

    This work concerns the thermal design of kettle reboilers. Current methods are highly inaccurate, regarded to the correlations for external heat transfer coefficient at one tube scale, as well as to two-phase flow modelling at boiler scale. The aim of this work is to improve these thermal design methods. It contains an experimental investigation with typical operating conditions of such equipment: an hydrocarbon (n-pentane) with low mass flux. This investigation has lead to characterize the local flow pattern through void fraction measurements and, from this, to develop correlations for void fraction, pressure drop and heat transfer coefficient. The approach is original, since the developed correlations are based on the liquid velocity at minimum cross section area between tubes, as variable characterizing the hydrodynamic effects on pressure drop and heat transfer coefficient. These correlations are shown to give much better results than those suggested up to now in the literature, which are empirical transpositions from methods developed for inside tube flows. Furthermore, the numerical code MC3D has been applied using the correlations developed in this work, leading to a modeling of the two-phase flow in the boiler, which is a significant progress compared to current simplified methods. (author)

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

    Science.gov (United States)

    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.

  19. Influence of Carbon Content on Fatigue Strength of Drawn Steel Tubes for Small Once-Through Boiler

    Science.gov (United States)

    Yonekura, Daisuke; Fujie, Yuta; Murakami, Ri-Ichi; Tokunaga, Yukihiro

    Tension-tension fatigue tests were performed to examine the influence of carbon content on the fatigue properties of drawn specific steel tube (STB340) with/without post heat treatment for small once-through boiler. Two different carbon content steel tubes, C=0.06 and 0.12% were prepared. The as-received, as-drawn and post drawing heat treated series for each carbon content tube were prepared for fatigue test. The hardness, grain size and residual stress were measured for each series. As a result, the fatigue strength of as-received and as-drawn series showed a small difference between C=0.06 and 0.12% specimens. However, the post drawing heat treatment series showed obvious difference in the fatigue strength. The fatigue strength of higher carbon content tubes significantly decreased by the post drawing heat treatment, whereas the decrease of fatigue strength was little for lower carbon content heat treated tubes. The difference of fatigue strength was mainly caused by the degree of relaxation of work hardening by post heat treatment.

  20. Use of Radioactive Tracers for Measuring the Density of the Emulsion (Water-Steam) Flowing in the Water-Wall Tubes of Industrial Boilers

    International Nuclear Information System (INIS)

    Introduction of a radioactive nuclide into the water offers a rapid procedure for diagnosing the functioning and properties of industrial boilers without altering the phenomena to be measured. The choice of radionuclide must satisfy strict criteria; after a large number of trials, a mixture of 186Re and 188Re obtained by neutron irradiation of natural rhenium was chosen. The background noise is measured at the time of the trials with the help of a system of three tubes placed in front of the boiler, or of one tube placed in an inspection chamber. The density of the emuision (water- steam) can be measured with an accuracy of between 10% and 15%. Trials were carried out on a boiler with a capacity of 3 tons of water operating under a pressure of 10kg/cm2 at 180°C. The emulsion density in several water-wall tubes was compared for different vapour flows, the density being measured along the whole length of the tube, which gives information on the thermal exchanges between the furnace and this tube. Trials will very soon be carried out on a power boiler belonging to Electricité de France (Creil Power Station). The personnel working around the boiler run no risk of irradiation since the quantities of radionuclide (10 to 25 μCi/litre of water) are small. The complete calculation of the isodose curves, verified by dosimetric measurements, shows that the dose 20 cm outside the boiler is below 90 mrads after 210 h, which is 6 or 7 times lower than the maximum tolerable dose. The dose is even smaller in the case of a large boiler. (author)

  1. Extending the erosion-corrosion service life of the tube system of heat-recovery boilers used as part of combined-cycle plants

    Science.gov (United States)

    Tomarov, G. V.; Mikhailov, A. V.; Velichko, E. V.; Budanov, V. A.

    2010-01-01

    We present the results from an analysis of damageability and determination of dominating mechanisms through which thinning occurs to the metal of elements used in the tube system of heat recovery boilers used as part of combined-cycle plants during operation and during their outages. Results obtained from putting in use a technology for making the tubes of such boilers more resistant to erosion-corrosion wear with the aid of film-forming amines are also presented. Measures are proposed on extending the service life of the tube system of heat recovery boilers used as part of combined-cycle plants and operating under the conditions of single- and two-phase flows.

  2. On the Design of Electric Heating Boiler Tube%浅谈电热管式电热锅炉的设计

    Institute of Scientific and Technical Information of China (English)

    叶承勇

    2015-01-01

    电热管式电热锅炉,因其具有无污染、效率高、安全性好、安装和维护方便、自动化程度高等特性得到迅速发展。文章主要以电热锅炉的锅壳结构形式及电热管的布置为重点,简要介绍电热管式电热锅炉的设计。%Electric boiler tube develops rapidly because of its non- pollution, high efficiency, safety, ease of installation and maintenance , and high degree of automation . Focusing on the heating boiler pot shell structure and electric tubes arrangement , this article will briefly introduce the electric boiler tube design .

  3. 锅炉拱形管板变形问题的研究%On the Deformation of Boiler Front Tube Sheet

    Institute of Scientific and Technical Information of China (English)

    牛志盛; 张杰; 李刚

    2016-01-01

    Through researches of the structure, deformation, leakage, experimental analysis of the boiler tube plate arch, this paper discusses the deformation of boiler front tube sheet and puts forward the improvement plans.%通过对拱形锅炉管板的结构、变形、泄漏、试验分析等一系列的情况研究,探讨锅炉前管板变形的问题,并提出改进方案。

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

    Energy Technology Data Exchange (ETDEWEB)

    I.I. Belyakov [Central Boiler-Turbine Institute Research and Production Association (OAO TsKTI), St. Petersburg (Russian Federation)

    2007-09-15

    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. Industrial mastering the use of tube fining by high-frequency welding for gasproof boilers

    International Nuclear Information System (INIS)

    Results of introduction of 20 and 12Kh1MF steel tube fining by high-frequency welding are presented. Heat treatment effect on properties of joints is studied, mechanical tests, metallographical and electron-microscopic investigations are carried out. It is shown that weld method of fins to tubes with the help of high-frequency currents is characterized by universality that permits to produce fined tubes of practically any diameter with fins of any width, control of smooth tubes before the fins welding to them being provided. Studies of properties of fined tubes has shown high quality of welded joints carried out by high-frequency current heating

  6. Experimental and numerical investigation of gas side particulate fouling onto heat exchanger tubes; Etude des differents mecanismes de depot conduisant a l'encrassement particulaire en phase gazeuse des tubes d'echangeurs de chaleur

    Energy Technology Data Exchange (ETDEWEB)

    Bailer, F.

    1998-11-06

    This works deals with gas side particulate fouling onto heat exchanger tubes. An experimental and numerical investigation was carried out. By means of a new testing loop designed for this study the deposit kinetics were obtained in dust-controlled conditions at the beginning of the fouling process, Experimental results pointed out the existence of various transport regimes: for sub-micron particles, convective diffusion augmented by thermophoresis in the presence of a temperature gradient governs the particle deposition: inertial impaction controls the super-micron particles deposition, in the intermediate granulometric range, combined action of particle inertia and thermophoresis must be considered. Moreover, measurements on an other testing loop using a more concentrated aerosol allowed us to point out the modification of the mechanisms with time and the influence of the deposit shape. A numerical model predicting the particle deposition, based on the TRIO software and an Eulerian-Lagrangian approach, was developed and validated against experimental results from the literature and from our study. Numerical approach gave us an accurate understanding of the phenomena by means of local parameters computations. In this way, the different mechanisms which control particulate deposition onto heat exchangers tubes were identified and modeled, especially before the onset of the inertial impaction. (authors)

  7. 糖厂锅炉爆管原因分析及对策%Analysis and countermeasures of sugar refinery boiler tube blasting

    Institute of Scientific and Technical Information of China (English)

    孔树学

    2012-01-01

    The sugar refinery boiler two successive water-wall tubes pipe explosion, through the pipe explosion running record check, after a broken tube boiler internal, blasting the shape of the mouth, blasting as pipe diameter changes, organize and performance of blasting mouth changes and tube wall and scaling inspection analysis, etc. Short-term overheat blowout of tube, its reason is run sugar.%某糖厂锅炉连续两次水冷壁管爆管,通过对爆管前的运行记录检查、爆管后锅炉内部、爆破口的形貌、爆破管的管径变化、爆破口的组织和性能变化及管内壁结垢等检验分析,属短期过热爆管,其原因是“跑糖”。

  8. 油田注汽锅炉炉管爆裂失效分析%Analysing on Failure Reason of Cracking Tube of Oiffield Streaming Boiler

    Institute of Scientific and Technical Information of China (English)

    孟媛媛; 王宇

    2011-01-01

    In order to find the crack reason, the material, macro-configuration, microstructure of the cracking tube, the fracture, water quality of the streaming boiler were checked. The reasons for the crack of streaming boiler are the overheating and over-pressing of the boiler tube.%为了弄清某油田注汽锅炉炉管爆裂的原因,分别对爆裂炉管的材质、爆裂炉管及其断口处的宏观形貌、显微组织及注汽锅炉水质等方面进行了全面检验,经分析得出注汽锅炉炉管爆裂是由于超温过载引起的.

  9. Analysis of High-temperature Boiler Tube Failure for T91 &T22

    Institute of Scientific and Technical Information of China (English)

    SHU Guo-gang; DING Hui; ZHAO Yan-fen; XUE Fei; ZHAO Ling-song; ZHANG Lu; LIU Jiang-nan; WANG Zheng-pin

    2004-01-01

    The tube failures took place frequently in the superheater of 2x600MW units in a power plant. According to the condition of tube failures, the mechanical property and microstructure on running and failed tubes were tested and evaluated. The chemical composition and structure phase of inner oxide scale and deposit inside of the tubes were examined.The fractured surfaces of failed tube samples were observed. And the material examination was performed for original tube steels SA213-T91 and SA213-T22. The results show that raw materials of SA213-T91 and SA213-T22 tube in superheater are qualified. Besides, the characteristics of the SA213-T91 and SA213-T22 tube failure are typical short-term overheated rupture. The rupture temperature is located between two phase Ac1 ~ Ac3 of the two steels. It is recognized that putting SA213-T22 tubes in operation under the condition of long-term over heating causes the rupture of SA213-T91 and SA213-T22.

  10. 余热锅炉爆管故障原因浅析%Waste heat boiler tube failure reason is analysed

    Institute of Scientific and Technical Information of China (English)

    付裕

    2014-01-01

    Dry quenching waste heat boiler tube through a company actual case, to analyze the causes of failure, and puts forward related Suggestions.%通过某公司干熄焦余热锅炉爆管实际案例,分析故障产生的原因,并提出相关建议。

  11. One Method of Solving Boiler Water wall Tubes High Temperture Gorrosion & Erosion%解决锅炉水冷壁管高温腐蚀和

    Institute of Scientific and Technical Information of China (English)

    胡双南; 许宏宇

    2009-01-01

    Adopting heat spray technique is a reliable method to solve boiler water wall tubes corrosion & erosion.%采用热喷涂技术是火电厂锅炉水冷壁高温防腐耐磨涂层最可靠的解决方法之一.

  12. 锅炉小径管焊缝超声波探伤%Boiler Tube Weld Ultrasonic Inspection Trails

    Institute of Scientific and Technical Information of China (English)

    侯耀民

    2014-01-01

    The main trail for boiler tube weld ultrasonic testing to start discussion outlines the instruments and test blocks used in testing and systematic analysis of the test methods and T91 trails pipe weld ultrasonic inspection process, in order to provide reference for detection work .%主要针对锅炉小径管焊缝超声波探伤展开探讨,简述了探伤所用的仪器和试块,并系统分析了检验方法和 T91小径管焊缝超声探伤过程,以期能为检测工作提供参考和借鉴。

  13. Pressure tests to assess the significance of defects in boiler and superheater tubing

    International Nuclear Information System (INIS)

    Internal pressure tests on 9 per cent Cr-1 per cent Mo steel tubing containing artificial defects demonstrated that the resultant loss of strength was less than a simple calculation based on the reduced tube thickness would suggest. Bursting tests on tubes containing longitudinal defects of varying length, depth and acuity showed notch strengthening at ambient temperature and at 5500C. A flow stress concept developed for simple bursting tests was shown to apply to creep conditions at 5500C. Results of creep and short-term bursting tests show that the length as well as the depth of the defect is an important factor affecting the life of bursting strength of the tubes. Defects less than 10 per cent of the tube thickness were found to have an insignificant effect. (author)

  14. A thin-lip rupture of carbon steel superheater boiler tube

    International Nuclear Information System (INIS)

    A ruptured A 42 medium carbon steel tube was collected by the engineering department in one of our steam power stations. Inspection of ruptured tube revealed a thin - lip fracture with brownish thin layer of oxide film on inner tube surfaces. There was no evidence of pitting, the outer surfaces of the tube exhibited a general oxidized conditions. A micro section taken near the fracture surface consists of ferrite and martensite, the amount of martensite decreased as we away from the fracture surface. Presence of martensite phase in the microstructure indicates that the tube material has been overheated. An erosion corrosion mechanism in conjunction with overheated. An erosion corrosion mechanism in conjunction with overheating resulted in strength deterioration with consequent premature failure. 4 fig., 1 tab

  15. Reproducibility of results of ultrasonic testing of welded joints of boiler heating surface tubes

    International Nuclear Information System (INIS)

    Reproducibility of the results of the ultrasonic inspection of welded joints of the heating surfaces of boilers depends substantially on the extent of differences between the frequency characteristics of selectors of the same type and on the spectrum of a probing signal. To assure the reproducibility and reliability of the results of the ultrasonic testing of the above joints it is necessary to ascertain the probing signal spectrum as the main parameter of the ultrasonic defectoscopy, and to standardize spectral characteristics of the selectors. The checking of the latter is carried out by means of a spectrum analyzer

  16. Specific features of flash welding of thin-walled boiler tubes

    International Nuclear Information System (INIS)

    The possibility of flash welding of pipes from Kh18N12T steel with walls less than 4 mm thick was investigated. The structure of welds was studied with the aid of X-ray and electron microscopy methods. The results of the work was the development of a procedure for flash welding boiler pipes 32 mm in diameter and with 2 mm thick walls. There is observed a partial burning out of titanium in the welded joint, the content of other alloying elements remaining unchanged. The contact resistance of the cross section being welded is usable for a programmed control of the welding process

  17. Design and implementation of a control system to improve the quality of the combustion gases in the fire-tube boiler of 5 BHP

    Directory of Open Access Journals (Sweden)

    Carlos Alfredo Pérez Albán

    2016-06-01

    Full Text Available The goal of this paper is the design and implementation of a system for controlling the quality of the combustion gases in a fire-tube boiler of 5 BHP. Based on the percentage of O2 present in the combustion gases, measured by a lambda sensor, the percentage of CO2 emitted into the atmosphere is determined. PID proportional control is responsible for the automatic regulation of the entry of air to the boiler by an actuator, according to the percentage of the oxygen concentration in the combustion gases. The control system has an HMI display and a modular PLC. The results achieved ensure pollutant gases emissions within the parameters established by current environmental standards, achieving the required quality of combustion gases and reducing the fuel consumption of the boiler.

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

    Science.gov (United States)

    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.

  19. Modelling of heat and flow phenomena occuring in waterwall tubes of boilers for supercritical steam parameters

    Science.gov (United States)

    Zima, Wiesław; Grądziel, Sławomir; Cebula, Artur

    2010-09-01

    In this paper a mathematical model enabling the analysis of the heat-flow phenomena occurring in the waterwalls of the combustion chambers of the boilers for supercritical parameters is proposed. It is a one-dimensional model with distributed parameters based on the solution of equations describing the conservation laws of mass, momentum, and energy. The purpose of the numerical calculations is to determine the distributions of the fluid enthalpy and the temperature of the waterwall pipes. This temperature should not exceed the calculation temperature for particular category of steel. The derived differential equations are solved using two methods: with the use of the implicit difference scheme, in which the mesh with regular nodes was applied, and using the Runge-Kutta method. The temperature distribution of the waterwall pipes is determined using the CFD. All thermophysical properties of the fluid and waterwall pipes are computed in real-time. The time-spatial heat transfer coefficient distribution is also computed in the on-line mode. The heat calculations for the combustion chamber are carried out with the use of the zone method, thus the thermal load distribution of the waterwalls is known. The time needed for the computations is of great importance when taking into consideration calculations carried out in the on-line mode. A correctly solved one-dimensional model ensures the appropriately short computational time.

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

    Science.gov (United States)

    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.

  1. A Numerical Model Prediction for Boiling Multi Channel Flow Rate Distribution and Application in 600MW Supercritical Variable-Pressure Once-Through Boiler with Vertical Tube Coils

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    Flow rate distribution is important in a multi channel system when the flow is heated non-uniformly,This paper describes a steady state approach for obtaining the flow distribution among various tubes of complex multi channel system,Based on the Present approach,a program has been developed which is directly applied in thermal hydraulic design and investigation of 600MW supercritical variable-pressure once through boiler.

  2. Evaluation of Thermocyclic Oxidation Behavior of HVOF-Sprayed NiCrFeSiB Coatings on Boiler Tube Steels

    Science.gov (United States)

    Ramesh, M. R.; Prakash, S.; Nath, S. K.; Sapra, Pawan Kumar; Krishnamurthy, N.

    2011-09-01

    High velocity oxy-fuel (HVOF) spray process has grown into a well-accepted industrial technology for obtaining coatings resistant to significant surface degradation processes. In the present study, HVOF process was used to deposit Ni-based hardfacing NiCrFeSiB alloy powder on kinds of boiler tube steels designated as SA210 grade-A1, SA213-T11, and SA213-T22. The microstructures and several properties of the as-sprayed coatings have been investigated. Thermocyclic oxidation studies were performed in static air at 900 °C. NiCrFeSiB-coated steels showed slow oxidation kinetics and considerably lower weight gains than that of uncoated steels. The superior performance of NiCrFeSiB coatings can be attributed to continuous and protective thin oxide scale of amorphous SiO2 and Cr2O3 formed on the surface of the oxidized coatings. The combined technique of x-ray diffraction, scanning electron microscopy, energy dispersive x-ray analysis, and electron probe microanalysis are used to characterize reaction products of the oxidized surfaces.

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

    Science.gov (United States)

    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.

  4. Causes and Characteristics for Frequent Tube Blasting of Utility Boiler%电站锅炉热管常见泄漏原因及主要特征

    Institute of Scientific and Technical Information of China (English)

    沈美华; 祝新伟; 潘金平; 程宏辉; 徐卫东

    2013-01-01

    电站锅炉受热面管内外广泛接触烟、火、灰、水、汽、垢等介质,其工作环境恶劣且复杂,经常会因为各种原因而导致爆管泄漏失效的发生,给企业带来巨大的经济损失.详细介绍了磨损、长期过热、短期过热、氢损伤、腐蚀疲劳、氧腐蚀、应力腐蚀、碱性腐蚀以及酸腐蚀9种常见的电站锅炉受热面管的泄漏失效原因及其主要特征,对迅速确定锅炉爆管原因以及提出解决措施,规范锅炉系统的操作等具有重要指导意义.%Heating surface tubes of utility boiler widely contact the media of smoke,fire,ash,water,steam,scale and etc.The tubes,which have wicked and complex working conditions,often blast and result in leakage failure because of many reasons.These bring huge economic losses to the enterprises.Nine kinds of tube blasting reasons and their main representation characters were detailedly introduced.These tube blasting reasons include abrasive erosion,long-term overheating,short term overheating,hydrogen damage,corrosion fatigue,oxygen corrosion,stress corrosion,caustic corrosion and acid corrosion.It has important guiding significance to rapidly ascertain the causes and ultimately resolve the tube blasting problems of the utility boiler and to normalize boiler system operation.

  5. High-temperature organic-fluid fouling unit

    Energy Technology Data Exchange (ETDEWEB)

    Kuru, W.C.; Panchal, C.B.

    1997-06-01

    A new type of fouling unit is developed for high-temperature (500 C) and high-pressure (70 atmosphere) fouling experiments by modifying a commercial autoclave. Key modifications are the installation of a helical impeller in a flow tube and a fouling probe in the autoclave to simulate the fluid dynamics and heat transfer of typical heat-exchange equipment. A calibration technique is described, and fouling results are presented for experimental runs with indene and kerosene. The results are compared with those obtained using other types of fouling test units. Other potential applications of the fouling unit, such as corrosion and micro-scale reaction experiments, are discussed.

  6. Steam generator chemical cleaning demonstration test No. 1 in a pot boiler

    International Nuclear Information System (INIS)

    The effectiveness of the Electric Power Research Institute (EPRI Mark I) chemical cleaning solvent process was tested utilizing a 12 tube pot boiler that had previously been fouled and dented under 30 days of high chloride fault chemistry operation. Specifically, the intent of this chemical cleaning test was to: (1) dissolve sludge from the tubesheet, (2) remove non-protective magnetite from dented tube/support crevice regions, and (3) quantify the extent of corrosion of steam generator material during the test. Two laboratory cleaning demonstrations of 191 and 142 hours were performed

  7. Inelastic behaviour of solar boiler tubes subjected to cyclic thermal loading

    International Nuclear Information System (INIS)

    Relying upon three-dimensional results previously obtained in the elastic range, we propose a simplified theory according to which each fiber of the tube portion undergoes either an uniaxial stress state (taking into account plastic flow with linear isotropic strain-hardening, possibly with creep) or a plane stress state in order to account for the ratchet phenomenon due to the inner fluid pressure. This approach allows to display and individualize the respective roles of strain-hardening, creep, fluid pressure and end-conditions; it also permits to calculate (most often in closed form) the deformations and stresses after a large number of cycles, which is not possible with more refined theories. Its accuracy has been assessed by computing the stresses and strains in the same situations for the first cycle by using an elasto-plastic shell theory (also taking into account creep influence), which revealed that in most cases our approach could give a good understanding of the phenomenon as well as a simple tool for actually calculating the mechanical quantities after a large number of cycles, in order to estimate the structure life-time. (orig./HP)

  8. Thermal Stress Analysis of Thin Tube - sheet for Waste Heat Boiler%管壳式废热锅炉薄管板的热应力分析

    Institute of Scientific and Technical Information of China (English)

    叶增荣

    2011-01-01

    Using the ANSYS, the higher and lower temperature tube - sheets of waste heat boiler were established. The higher temperature tube - sheet included high temperature resistant structure. The temperature field and the stress field of two tube - sheets were analyzed respectively. Then the stress distribution of tube - sheets and the placement of the maximum, stress were obtained. The results indicated that using the high temperature resistant structure in higher temperature tube - sheet can improve the stress distribution of tube - sheet effectively.%运用ANSYS对管壳式废热锅炉建立了含有管板及管头高温热防护结构的热端管板及不合高温热防护结构的冷端管板两种有限元模型,分析了高低温管板的温度场及应力场,分别得出了管板上的应力分布及最大应力发生部位.结果表明,采用高温热防护结构可以有效地改善热端管板的应力分布.

  9. Ultrasonic water level determination of the high-pressure boilers tubes; Determinacao do nivel d'agua em tubos verticais de caldeiras aquatubulares por ultra-som

    Energy Technology Data Exchange (ETDEWEB)

    Goettems, Felipe Samuel; Reolon, Amon Marques; Avancini, Flavio; Braga, Rubem Manoel de; Reguly, Afonso [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Lab. de Metalurgia Fisica], e-mail: fgoettems@demet.ufrgs.br

    2006-07-01

    Electric power is very important to our society and thermoelectric power plant. They are especially important mainly in the summer when there is a scarcity in water supply to hydroelectric power plants. Southern Brazilian thermoelectric power plants employ high-pressure boilers in order to generate water vapor which, in turn, moves turbines to produce electricity. These high-pressure boilers must work in a continuous way to avoid damages caused by emergency halts. To accomplish this, some actions must be taken. The water height inside of the tubes must be kept in a strict level to avoid thermal gradient in both water walls and super-heater header. In this water walls the water become in vapor. The best way to regulate the valves that command the water level is through the control of the water height and this is the main purpose of this work. The ultrasound is a nondestructive test which is able in doing this control without damaging the tube. This method allows determining the water level, improving the system performance and reducing the maintenance costs caused by tube collapse. (author)

  10. 奥氏体不锈钢高温锅炉管失效分析%Failure Analysis of Austenitic Stainless Steel Boiler Tubes in High-Temperature

    Institute of Scientific and Technical Information of China (English)

    蔡晓辉; 刘峰

    2012-01-01

    采用金相显微镜、扫描电镜以及拉伸、冲击、显微硬度测试等检测手段,对高温临氯环境下开裂的奥氏体不锈钢锅炉管进行失效原因分析.分析结果表明,奥氏体不锈钢高温锅炉管断裂为典型的疲劳—蠕变断裂模式,裂纹形态为穿晶沿晶混合萌生、沿晶扩展.高温不锈钢炉管在运行过程中承受较大的热应力,在锅炉频繁起停过程中应力不断循环变化,导致构件承受疲劳与蠕变交互作用并最终使奥氏体不锈钢锅炉管开裂.%The failure mechanism of an austenitic stainless steel boiler tube under high temperature and hydrogen environment was investigated by optical and scanning electron microscope. Mechanical properties of the boiler tube were also studied by tensile, impact and hardness tests. The results show that high -temperature creep -fatigue cracking is the major reason for the failure of this component. From the morphology of view, the cracks initiate in a mixed mode and propagated in a typical intergranular way. High temperature stainless steel tubes in the boiler are subjected to high thermal stress during frequent starting and shutting down, causing fatigue and creep interaction in the material, and eventually leading to the final failure.

  11. Based on the acoustic emission technology Boiler "Four Tubes" leakage detection system%基于声发射技术的锅炉“四管”泄漏检测系统

    Institute of Scientific and Technical Information of China (English)

    张里阳

    2014-01-01

    针对电厂中锅炉“四管”泄漏时产生的广义声发射现象,对空间声场分布和声发射信号进行了分析研究。通过采集这种声发射信号并分析处理,建立了检测锅炉“四管”泄漏的检测系统,即锅炉炉管泄漏自动报警系统,给出了检测系统的软、硬件设计。该系统能够实现对锅炉炉管泄漏的早期测报,并判断出泄露的区域位置及泄漏程度,防止事故扩大,减少经济损失。%According to the power plant boiler "four tube" leakage in the generalized acoustic emission phenomenon, On the space sound field distribution and acoustic emission signal is studied. Through collecting and analyze the acoustic emission signal processing, detection is established boiler "four tube" leakage detection system, The boiler furnace tube leakage automatic alarm system, Detection system hardware and software design are also given in this paper. The system can realize early telemetry of boiler tube leakage, can realize early telemetry of boiler tube leakage, to prevent accidents, reduce economic loss.

  12. Research on database system of boiler heated tube supervision and inspection%火电厂锅炉受热面金属监督检验数据库系统研究

    Institute of Scientific and Technical Information of China (English)

    刘立鹏

    2014-01-01

    结合理论与现场检验实践经验,总结电站锅炉受热面常见爆漏原因,建立数据库系统,为火电厂锅炉检修维护提供参考。%Combination of theory and empirical, summary of common causes of boiler heated tube leak, establish a database system, provide a reference for thermal power plant boiler repair and maintenance.

  13. Analysis and Prevention of the Crack on the Smoke Tube End and Tube Sheet in the Gas Boiler%燃气锅炉烟管管端和管板裂纹分析及防止

    Institute of Scientific and Technical Information of China (English)

    王明强; 吴金星; 王超; 刘艳会

    2016-01-01

    The smoke tube end and tube plate often generate cracks during the long-term operating of gas boiler, the main reason of which is big thermal loading, serious scaling of tube plate, caustic embrittlement, etc. Aimed at the causes of various cracks, and combining with engineering cases, this paper expounds the prevention measures, such as adding insulation layer to gas side of tube plate, strengthening water cycle, improving manufacturing process and strengthening water quality management, to make the working conditions of smoke tube end and tube plate highly improved so as to prevent the occurrence of cracks and ensure the operating of boiler safely and efifciently.%燃气锅炉在长期运行中烟管管端及管板常常产生裂纹,其主要原因是热负荷较大、管板结垢严重、苛性脆化等。本文针对各种裂纹产生的原因并结合工程案例,阐述了管板烟气侧加设隔热层、加强水循环、改善制造工艺、加强水质管理等防止措施,使烟管管端及管板工作条件得到很大改善,以防止裂纹的发生,保证锅炉安全、高效地运行。

  14. A Study of the Effect of Kaolin as a Fuel Oil Additive on the Corrosion Inhibition of Fireside Superheater Boiler Tubes

    Directory of Open Access Journals (Sweden)

    Alaa' Mshjel Ali

    2010-01-01

    Full Text Available The objective of the present study is to determine the effect of Kaolin as a fuel oil additive to minimize the fireside corrosion of superheater boiler tubes of ASTM designation (A213-T22 by increasing the melting point of the formed slag on the outside tubes surface, through the formation of new compounds with protective properties to the metal surface. The study included measuring corrosion rates at different temperatures with and without additive use with various periods of time, through crucible test method and weight loss technique.A mathematical model represents the relation between corrosion rate and the studied variables, is obtained using statistical regression analysis. Using this model, the best additive to ash weight ratio was specified. Then scanning electron microscopic images taken to the two treated and untreated samples with additive to study the difference in nature of slag formed on the metal surface to the two cases.

  15. Modelling, simulating and optimizing Boilers

    DEFF Research Database (Denmark)

    Sørensen, Kim; Condra, Thomas Joseph; Houbak, Niels

    2003-01-01

    This paper describes the modelling, simulating and optimizing including experimental verication as being carried out as part of a Ph.D. project being written resp. supervised by the authors. The work covers dynamic performance of both water-tube boilers and re tube boilers. A detailed dynamic mod...

  16. 一起锅炉烟管漏水质量事故的分析及解决办法%Analysis and Solution for Shell Boiler Tube Leakage Accident

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      通过一起锅壳式锅炉烟管漏水的质量事故,分析产生漏水缺陷的几种原因,指出烟管挠度过大,导致运输途中产生较大的挠变作用力,该作用力与烟管角焊缝根部应力集中的共同作用,是烟管形成冷裂纹漏水的主要原因。针对主因提出了增加烟管支撑等解决办法。%Based on a shell boiler tube leakage quality accident, analyzes the reasons for leaking defect. According to the analysis, boiler fire tube defection is too large, it leads to larger defection force in the transport process, with the fire tube fillet weld stress concentration,which are the major causes of boiler tube forming cold crack leakage. In view of the main reasons, put forward a solution to increase the boiler tube support.

  17. A CFD study on the dust behaviour in a metallurgical waste-heat boiler

    Energy Technology Data Exchange (ETDEWEB)

    Yang Yongxiang; Jokilaakso, A. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Materials Processing and Powder Metallurgy

    1997-12-31

    A waste-heat boiler forms an essential part for the treatment of high temperature flue-gases in most metallurgical processes. Flue-dust carried by the furnace off-gas has to be captured efficiently in the waste-heat boilers before entering the downstream gas purification equipment. Flue dust may accumulate and foul on the heat transfer surfaces such as tube-walls, narrow conjunctions between the boiler and the furnace uptake, and thus may cause smelter shutdown, and interrupt the production. A commercial CFD package is used as the major tool on modelling the dust flow and settling in the waste-heat boiler of an industrial copper flash smelter. In the presentation, dust settling behaviour is illustrated for a wide range of particle sizes, and dust capture efficiency in the radiation section of the boiler for different particle sizes has been shown with the transient simulation. The simulation aims at providing detailed information of dust behaviour in the waste-heat boiler in sulphide smelting. (author) 11 refs.

  18. Cause analysis of leakage by tube failure of power station boiler%电站锅炉管件失效泄漏原因分析

    Institute of Scientific and Technical Information of China (English)

    岳忠; 张月山

    2012-01-01

    Tube burst accident of heating surface tubes in a thermal power plant takes place frequently, which seriously affects the safety and economic operation of thermal power plant. In this paper the tube failure leakage accidents of economizer and low temperature reheater in a power plant were analyzed. Three kinds of methods were applied, including macroscopic analysis, metallographic analysis and strength analysis. It showed that overheating was not the cause of this tube burst. Oxygen corrosion and defects of low reheater leaded tube leakage. Then leaking fluid from low temperature reheater tube caused fluid scour and cavitations erosion on the rear wall economizer. Fluid scour and cavitations erosion leaded leakage of the rear wall economizer. The fluid from the rear wall economizer tube caused fluid scour and cavitations erosion on the low reheater which strengthened leakage of low reheater. At last the treatment measure and proposals of preventing similar accident were put forward. The failure tube should be replaced. The examination and test of metal tube should be paid attention to during boiler maintenance. Metal tube which is easy to be scoured should be put on protection covering or coating to prevent from fluid scouring.%火力发电厂管件失效泄漏是频发事故,严重影响机组的安全、经济运行.以某发电厂后墙省煤器和低温再热器管子失效泄漏事故为例,通过对失效泄漏的管件进行宏观形貌分析、金相分析和强度分析,论证了泄漏事故的原因是由于腐蚀和钢管固有缺陷导致低温再热器高温段弯管外侧发生泄漏,泄漏的高速流体冲刷、气蚀导致后隔墙省煤器发生泄漏,进而对低温再热器反冲刷,加剧泄漏事故的恶化.最后提出更换失效管件,加强金属监督,尽量扩大防磨防爆检查范围,对易被气流磨损、冲刷部位进行防磨喷涂或加装防磨罩.

  19. Failure Analysis of 600 MW Supercritical Boiler Water Wall

    OpenAIRE

    Fu Huilin; Cai Zhengchun; Yan Xiaozhong; He Jinqiao; Zhou Yucai

    2013-01-01

    Boiler tube often causes abnormal boiler outage, bringing greater economic losses. This thesis mainly comes from the dynamics of boiler water, boiler furnace accident location of wall temperature distribution to explore the cause of the accident boiler. Calculation results show that the deformation will seriously reduce the boiler allowable maximum temperature difference between the screens. And the boiler is not over-temperature, low temperature difference between the screens, which have bur...

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

    Science.gov (United States)

    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.

  1. 49 CFR 230.61 - Arch tubes, water bar tubes, circulators and thermic siphons.

    Science.gov (United States)

    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... 49 Transportation 4 2010-10-01 2010-10-01 false Arch tubes, water bar tubes, circulators...

  2. Analysis on leakage reasons of tube sheet (tube mouth) on WNS gas steam boiler%WNS 型燃气蒸汽锅炉管板(管口)泄漏原因分析

    Institute of Scientific and Technical Information of China (English)

    薛峰; 卢忠铭; 王恋

    2015-01-01

    某医院有两台WNS10-1.25-Y/Q燃气锅炉,连续发生多次回燃室前管板烟管管口泄漏故障,分析了缺陷产生的原因,并提出了解决方法。在长期交变热应力作用下,烟管管口角焊缝熔合线区域产生内部微裂纹,微裂纹在交变热应力(断口分析的形貌为韧窝)的作用下逐步扩展,形成内部宏观(金相检验时发现了多条内部裂纹,且裂纹走向是平行于烟管轴向的方向),裂纹沿着轴向向烟管前后端扩展,最终扩展到管端,并穿透管壁,导致锅炉汽水从裂口泄漏。%There exists 2 WNS10-1.25-Y/Q gas boilers in a certain hospital, and the leakage faults have occurred in the tube mouth of smoke tube on front tube sheet of reversal chamber for several times continuously.The reasons of defects were analyzed, and the solving methods were put forward.Under the long term action of tremendous ther-mal stress, the internal micro cracks came into being in the fillet weld junction region on tube mouth of smoke tube. The micro cracks expanded gradually under the action of tremendous thermal stress ( the morphology of fracture a-nalysis is dimple) , and formed the internal macro ( multiple internal cracks were found in metallographic examina-tion, and the crack path was parallel to the axial direction of smoke tube) .The cracks expanded to the front end and back end of smoke tube, and finally reached the tube end, then penetrated the wall of tube, resulting in leak-age of steam-water from the gap.

  3. Failure Analysis of Platen Superheater Tube of Fuel-oil Boiler%炼厂燃油锅炉屏式过热器管失效分析

    Institute of Scientific and Technical Information of China (English)

    莫烨强; 罗建成; 孙亮; 侯艳宏

    2014-01-01

    采用宏观观察、金相观察、扫描电子显微分析、成分分析等分析方法,对燃油锅炉屏式过热器发生开裂失效原因进行了分析研究。结果表明:该管长期在高温下运行产生了蠕变现象;珠光体组织出现严重的球化现象,大量碳化物呈链状沿晶界析出;过热器管道内壁存在约371.55μm厚度的氧化层。因此,管束长期局部过热服役,致使金相组织发生改变,大大降低了材料的力学性能,从而发生蠕变开裂现象。%The failure reasons of a platen superheater tube of a fuel-oil boiler were studied by macroscopic observation, metallographic analysis, scanning electron microscopy ( SEM ) and energy dispersive spectroscopy ( EDS ) . The result of macroscopic observation shows that creep cracking happened to the tube after working for a long time at high temperature. The result of metallographic analysis shows that the carbide precipitated at grain boundaries. The result of scanning electron microscopy( SEM) and energy dispersive spectroscopy( EDS) show that a oxidation layer formed on the inside of the tube. The thickness of the oxidation layer was 371. 55μm. It can be concluded that long-term local overheating occurred to the tube during working, leading to microstructure change and reducing the mechanical properties of the material.

  4. Discussion and Analysis of the Causes of Accident of Steam Boiler Tube Rupture and the Processing Methods%蒸汽锅炉爆管事故原因及处理方法探讨分析

    Institute of Scientific and Technical Information of China (English)

    李伟忠; 安文广; 张丽波

    2012-01-01

    蒸汽锅炉在运行过程中,一旦发生爆管事故,会损坏邻近的管壁,冲塌炉墙,并且在很短的时间造成锅炉严重缺水,使事故扩大,因此须保证安全可靠,确保安全生产运行.本文主要探讨蒸汽锅炉运行中锅炉爆管事故原因及处理方法.%Once the accident of tube rupture for steam boiler during operation happened, it can damage the nearby tube wall, and collapse furnace wall, resulting in serious water shortages for boiler in a very short period of time, expanding the accident, therefore, we must ensure the safety and reliability, safe production and operation. This paper mainly discusses the causes and treatment methods of accident of boiler tube rupture in the operation of steam boiler.

  5. Fouling of Structured Surfaces during Pool Boiling of Aqueous Solutions

    International Nuclear Information System (INIS)

    Bubble characteristics in terms of density, size, frequency and motion are key factors that contribute to the superiority of nucleate pool boiling over the other modes of heat transfer. Nevertheless, if heat transfer occurs in an environment which is prone to fouling, the very same parameters may lead to accelerated deposit formation due to concentration effects beneath the growing bubbles. This has led heat exchanger designers frequently to maintain the surface temperature below the boiling point if fouling occurs, e.g. in thermal seawater desalination plants. The present study investigates the crystallization fouling of various structured surfaces during nucleate pool boiling of CaSO4 solutions to shed light into their fouling behaviour compared with that of plain surfaces for the same operating conditions. As for the experimental part, a comprehensive set of clean and fouling experiments was performed rigorously. The structured tubes included low finned tubes of different fin densities, heights and materials and re-entrant cavity Turbo-B tube types.The fouling experiments were carried out at atmospheric pressure for different heat fluxes ranging from 100 to 300 k W/m2 and CaSO4 concentrations of 1.2 and 1.6 g/L. For the sake of comparison, similar runs were performed on plain stainless steel and copper tubes.Overall for the finned tubes, the experimental results showed a significant reduction of fouling resistances of up to 95% compared to those of the stainless steel and copper plain tubes. In addition, the scale formation that occurred on finned tubes was primarily a scattered and thin crystalline layer which differs significantly from those of plain tubes which suffered from a thick and homogenous layer of deposit with strong adhesion. Higher fin densities and lower fin heights always led to better antifouling performance for all investigated finned tubes. It was also shown that the surface material strongly affects the scale formation of finned tubes i

  6. Degradation behavior of Ni{sub 3}Al plasma-sprayed boiler tube steels in an energy generation system

    Energy Technology Data Exchange (ETDEWEB)

    Sidhu, B.S.; Prakash, S. [GZS, Bathinda (India). College of Engineering

    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{mu} m thick layer sprayed onto the surface before applying the 200{mu}m coating of Ni{sub 3}Al. Exposure studies have been performed in the platen superheater zone of a coal-fired boiler at around 755{sup o}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.

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

    Science.gov (United States)

    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.

  8. [Fouling: terminology and definitions].

    Science.gov (United States)

    Khalaman, V V

    2009-01-01

    Current classification of principal ecological groups of hydrobionts is an eclectic one as it confuses two fundamentals, one dealing with organismic ecomorphology and another with water body's topology. This leads to difficulties in determination of interrelations between benthos and fouling communities. The littoral fouling communities cannot be considered as an independent ecological group of the same rank as plankton or benthos because it lacks a unique species composition. The fouling is always a derivate of the benthos, so it could be defined as a community formed by benthic organisms during succession on a solid substrate more or less remote from the water body's bottom. All peculiarities of the fouling communities distinguishing them from similar benthic communities are determined by topology and other properties of the substrate, by relatively short period of the latter's exposition and by hydrological conditions under which the fouling is developing. There is continual transitions between benthic and fouling communities both in space (along gradients of abiotic environmental factors) and in time (along successional series). Such a continuum becomes most frequently broken due to both significant remoteness of the substrate, on which a fouling develops, from the bottom and permanent extreme factors disturbing or retarding fouling communities development. Thus, littoral foulings are just benthos being formed under specific conditions. At the same time, oceanic foulings are connected both evolutionary and ecologically with littoral foulings and benthos. PMID:20063771

  9. Desain Compact Heat Exchanger Tipe Fin And Tube Sebagai Alat Pendingin Motor Pada Boiler Feed Pump. Studi Kasus Pada Sebuah Perusahaan Pembangkit Tenaga Listrik

    Directory of Open Access Journals (Sweden)

    Luki Apriliasari

    2013-09-01

    Full Text Available Motor listrik penggerak boiler feed pump harus bekerja secara kontinyu, dan hanya boleh mati pada saat dilakukan maintenance, apabila tidak diberikan pendinginan maka akan terjadi overheating dan menyebabkan kerusakan pada motor. Hal ini sering terjadi di PLTU, motor listrik hanya didinginkan dengan dialiri udara bebas. System ini memiliki keterbatasan yaitu kotoran yang terkandung di udara bisa menempel di dinding motor, justru menyebabkan panas dalam motor tidak keluar dengan maksimal. Untuk mengatasi keterbatasan tersebut, maka diusulkan suatu metode pendinginan yaitu dengan mendesain heat exchanger tipe compact (fin and tube. Data – data operasi diambil dari suatu perusahaan pembangkit tenaga listrik yang dijadikan obyek study. Perhitungan desain heat exchanger dengan metode ∆TLMTD. Setelah mendapat dimensi yang sesuai dengan panas yang akan didinginkan, maka dilakukan analisa performansi yaitu nilai effectiveness terhadap perubahan beban. Hasil yang didapatkan dari penyelesaian study kasus ini adalah dimensi compact heat exchanger yang memiliki spesifikasi sesuai surface 7.75-5/8T dari Kays and London dengan panjang fin 1 meter, lebar fin 0,3 m, dan panjang tube 1 meter. Hasil analisa performansi (effectiveness terhadap variasi beban yaitu semakin tinggi pembebanan maka nilai effectiveness juga semakin tinggi.

  10. 600MW超临界锅炉过热器爆管原因及改进措施%Cause Analysis and Improvement Measures on Heater Tube Cracking of 600MW Supercritical Boiler

    Institute of Scientific and Technical Information of China (English)

    祝毅; 杨宁; 徐耀良; 陈元良

    2011-01-01

    Through comprehensive analysis on the tubes cracking accident that happened at final superheater of 600 MW supercritical boiler,it is concluded that the accident is caused by short-term overheating tube rupture.Oxide scale falling off leading to series oxidation of tube wall and stoppage is the main reason of tube rupture.Several effective countermeasures for this accident,such as no boiler over-temperature operation,strengthening the management of water quality,flushing the deposit of oxide scale promptly,and increasing measuring point at the boiler final superheater to reflect the temperature conditions of the tube wall as comprehensively as possible,are proposed accordingly.The boiler operates well after applying these improvement measures.%通过对某600 MW超临界锅炉末级过热器的爆管进行综合分析,确定爆管属于超临界锅炉管道短时超温爆管。锅炉管壁严重氧化和大量脱落造成堵塞,是锅炉爆管的主要原因。为此提出了一些有效的防范措施,包括严禁锅炉超温运行,加强水质管理以及及时冲洗沉积的氧化皮等,并增加锅炉过热器管壁测点,尽可能全面地反映管壁温度状况。采用这些措施后锅炉的运行状况良好。

  11. Analisa Efisiensi Water Tube Boiler Berbahan Bakar Fiber dan Cangkang di Palm Oil Mill Dengan Kapasitas 45 Ton TBS/Jam

    OpenAIRE

    Batubara, Pesulima

    2015-01-01

    Beberapa faktor yang mempengaruhi efisiensi boiler adalah tekanan superheater, temperatur air umpan, temperatur uap, jumlah uap yang dihasilkan, jumlah konsumsi bahan bakar, dan nilai kalor pembakaran bahan bakar. Penggunaan software chemicallogic steamtab companion untuk menghitung nilai enthalpy. Tujuan dari penelitian ini adalah mendapatkan hubungan variasi tekanan superheater dengan efisiensi boiler, hubungan variasi suhu air umpan dengan efisiensi boiler, hubungan variasi jumlah uap yang...

  12. Further development of recovery boiler; Soodakattilan kehitystyoe

    Energy Technology Data Exchange (ETDEWEB)

    Janka, K.; Siiskonen, P.; Sundstroem, K. [Tampella Power Oy, Tampere (Finland)] [and others

    1996-12-01

    The global model of a recovery boiler was further developed. The aim is to be able to model the velocity, temperature and concentration fields in a boiler. At this moment the model includes submodels for: droplet drying, pyrolysis, char burning, gas burning and for droplet trajectory. The preliminary study of NO{sub x} and fly ash behaviour in a boiler was carried out. The study concerning flow field in the superheater area was carried out a 2-dimensional case in which the inflow parameters were taken from global model of a recovery boiler. Further the prediction methods of fouling in a recovery boiler were developed based on theoretical calculations of smelting behaviour of multicomponent mixtures and measurements at operating recovery boilers. (author)

  13. Cracking and corrosion recovery boiler

    Energy Technology Data Exchange (ETDEWEB)

    Suik, H. [Tallinn Technical University, Horizon Pulp and Paper, Tallinn (Estonia)

    1998-12-31

    The corrosion of heat surfaces and the cracking the drums are the main problems of the recovery boiler. These phenomena have been appeared during long-term operation of boiler `Mitsubishi - 315` erected at 1964. Depth of the crack is depending on the number of shutdowns and on operation time. Corrosion intensity of different heat surfaces is varying depend on the metal temperature and the conditions at place of positioning of tube. The lowest intensity of corrosion is on the bank tubes and the greatest is on the tubes of the second stage superheater and on the tubes at the openings of air ports. (orig.) 5 refs.

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

    Science.gov (United States)

    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.

  15. 超超临界电站锅炉小径管焊缝超声波探伤%Ultrasonic Testing of the Welds of Small Caliber Tube in the Ultra Supercritical Power Station Boiler

    Institute of Scientific and Technical Information of China (English)

    朱健

    2011-01-01

    对T91材质的电站锅炉小径管焊缝进行了超声波检测,使用常规探头以及试块来调节扫描声速.%The ultrasonic testing was done to the welds of small caliber tube of T91 material in the power station boiler, and the scan speed was adapted by normal probe.

  16. High temperature properties of the seam weld portion in 1% Cr-0.5% Mo ERW boiler tubing after long-term aging

    International Nuclear Information System (INIS)

    This study is aimed at the evaluation of reliability of the seam weld portion of 1% Cr-0.5% Mo ERW (Electric Resistance Welding) boiler tubings for high temperature use. High temperature properties of materials aged in the temperature between 500 and 6000C for 5000 h were evaluated by a slow extension rate test (SERT) and a low cycle fatigue test at high temperatures. Microscopic observation was also made with a scanning electron microscope and a transmission electron microscope. Proof stress and tensile strength obtained by SERT tend to decrease with an increase in aging temperature. It is confirmed that the strength of the seam weld portion is higher than that of the base metal. The fatigue crack propagation rates studied by test pieces with a side-notch either at the base metal or at the seam weld portion were found to be lower at the seam weld portion compared with that at the base metal. Dislocations of high density and fine precipitates of carbides were observed with electron microscopy in the seam weld portion. It is also found that the size of dislocation cells formed during fatigue is smaller in the seam weld portion than in the base metal. It is concluded that higher strength of the seam weld portion is closely related to the above mentioned microstructure originated in the dissolution of carbides during ERW process. 10 figures, 3 tables

  17. High-Temperature Erosion of HVOF Sprayed Cr3C2-NiCr Coating and Mild Steel for Boiler Tubes

    Science.gov (United States)

    Yang, Guan-Jun; Li, Chang-Jiu; Zhang, Shi-Jun; Li, Cheng-Xin

    2008-12-01

    The comparison of the high-temperature erosion behavior of a High-velocity oxyfuel (HVOF) sprayed Cr3C2-NiCr coating with mild steel for circulating fluidized bed boiler tubes was investigated. Results showed that the erosion rate of the mild steel at 800 °C was four times that at 300 °C at an erosion angle of 30°. However, the erosion rate of the HVOF sprayed Cr3C2-NiCr coating was not influenced by the temperature in the range of 300-800 °C. It was found that the erosion resistance of HVOF sprayed Cr3C2-NiCr coating was more than three times higher than that of the mild steel at 700-800 °C. In addition to the ploughing on the coating surface, the cracking along splat interfaces in the coating was clearly observed on the cross-sectional microstructure. The results indicate that the erosion performance of the HVOF sprayed Cr3C2-NiCr coating is controlled by the cohesion between splats and can be further enhanced by improving splat cohesion.

  18. Analysis and Preventive Measures for Tube Bursting of High-pressure Pulverized Coal Boiler%高压煤粉锅炉爆管原因分析及防治措施

    Institute of Scientific and Technical Information of China (English)

    肖宇

    2012-01-01

    Tube bursting and leakage frequently occurred for four high-temperature,high-pressure pulverized coal boilers in a power plant since original operation.Those tube bursting phenomena were classified,and the causes of tube bursting and leakage were analyzed from the tube materials,boiler control technology and design.Some prevention and control measures for the tube explosive and leakage were proposed based on on-site operation,maintenance,and management.%某电厂4台高温、高压煤粉锅炉自投产以来经常发生四管爆漏现象,本文对这些爆管现象进行了统计和归类,并从管束材料、锅炉控制工艺和设计等方面,分析了锅炉爆管、泄露的原因;同时,从锅炉运行、现场检修、运行管理和材料采购等方面提出了锅炉四管爆漏的防治措施。

  19. Failure Analysis of 600 MW Supercritical Boiler Water Wall

    Directory of Open Access Journals (Sweden)

    Fu Huilin

    2013-07-01

    Full Text Available Boiler tube often causes abnormal boiler outage, bringing greater economic losses. This thesis mainly comes from the dynamics of boiler water, boiler furnace accident location of wall temperature distribution to explore the cause of the accident boiler. Calculation results show that the deformation will seriously reduce the boiler allowable maximum temperature difference between the screens. And the boiler is not over-temperature, low temperature difference between the screens, which have burst pipe. Analysis of the deformation of the boiler and propose solutions.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, William (Sandy) [SharpConsultant

    2011-12-01

    the measured first melting point of fly ash deposits does not necessarily produce a step increase in corrosion rate. Corrosion rate typically accelerates at temperatures below the first melting temperature and mixed deposits may have a broad melting temperature range. Although the environment at a superheater tube surface is initially that of the ash deposits, this chemistry typically changes as the deposits mature. The corrosion rate is controlled by the environment and temperature at the tube surface, which can only be measured indirectly. Some results are counter-intuitive. Two boiler manufacturers and a consortium have developed models to predict fouling and corrosion in biomass boilers in order to specify tube materials for particular operating conditions. It would be very useful to compare the predictions of these models regarding corrosion rates and recommended alloys in the boiler environments where field tests will be performed in the current program. Manufacturers of biomass boilers have concluded that it is more cost-effective to restrict steam temperatures, to co-fire biofuels with high sulfur fuels and/or to use fuel additives rather than try to increase fuel efficiency by operating with superheater tube temperatures above melting temperature of fly ash deposits. Similar strategies have been developed for coal fired and waste-fired boilers. Additives are primarily used to replace alkali metal chloride deposits with higher melting temperature and less corrosive alkali metal sulfate or alkali aluminum silicate deposits. Design modifications that have been shown to control superheater corrosion include adding a radiant pass (empty chamber) between the furnace and the superheater, installing cool tubes immediately upstream of the superheater to trap high chloride deposits, designing superheater banks for quick replacement, using an external superheater that burns a less corrosive biomass fuel, moving circulating fluidized bed (CFB) superheaters from the

  1. 火电厂锅炉水冷壁管横向裂纹开裂原因分析%Failure Analysis on Water Wail Tube Transversal Crack of Power Plant Boiler

    Institute of Scientific and Technical Information of China (English)

    杨峰; 崔玮; 韩福全

    2011-01-01

    对电厂锅炉水冷壁管与鳍板焊接处开裂原因进行失效分析.结果表明:水冷壁管向火一侧表面氧化严重,管内侧存在结垢现象,同时水冷壁管珠光体发生球化,在运行过程中,在循环热应力和焊接残余应力叠加作用下,裂纹在焊缝接头处萌生,沿着拉应力区扩展,造成疲劳开裂.%The crack reason of the water wall tube in power plant boiler which attached to the welding with the fin tube wall was analyzed. The results show that superficial oxidation takes place on the appearance of water wall tube, typical scaling scale exists on the internal surface and partial pearlite is spheroidized. Cracks initiate in areas with attachment weld,leading to the explosion of the water wall tube in the boiler due to the cycle thermal stress and welding stress.

  2. Rupture Causes Analysis and Countermeasures on Rear Platen Superheater Tube of 300 MW Power Station Boiler%300MW电站锅炉后屏过热器爆管原因分析和对策

    Institute of Scientific and Technical Information of China (English)

    黎小秋; 赵康文; 唐囡; 何可龙

    2012-01-01

    Based on the experimental data, an failure analysis about the causes of the dissimilar steel weld joints rupture in the rear platen superheater tube of a large power plant boiler has been done. The results demonstrated that the enriched carbon layers around the melting line, residual stress and stress concentration leads to a premature failure of the dissimilar steel weld joints, and the retrofitting measures are introduced to ensure the safe operation of the power station boiler. At the same time, it can also supply references to the failure analysis of the similar structure boiler heating tubes.%在试验的基础上,对某大型电站锅炉后屏过热器管异种钢焊缝破裂的原因进行了失效分析,结果表明熔合线增碳层,残余应力和应力集中导致了异种钢焊缝的早期失效,并提出了相应的改进措施以确保电站锅炉安全运行,同时,也可为同类型结构锅炉受热面管的失效分析提供参考.

  3. Common Hot Water Boiler Front Tube Plate Crack Causes and Repair Methods%常见热水锅炉前管板裂纹产生原因及维修方法

    Institute of Scientific and Technical Information of China (English)

    杨睿

    2014-01-01

    对锅炉在焊接应力过大、传热不均衡、污垢下锅炉的腐蚀疲劳压力过大等各种综合因素的影响下,其烟管、管板焊接与管板孔桥产生裂纹的原因进行分析,并探讨了合理、有效的维修手段,希望能为蒸汽锅炉的安全运行提供可靠保障。%The causes of the boiler under the influence of welding stress is too large, uneven heat, corrosion fatigue dirt under pressure boiler combination of factors such as excessive, the smoke pipe, tube sheet welding and tube sheet hole bridge cracks were analyzes and discusses the rational and effective means of repair, hoping to provide a reliable guarantee for the safe operation of steam boilers.

  4. Efficiency and effect of different soot blowing methods on boilers using different types of fuels; Sotningsmetodernas effektivitet och konsekvenser paa foerbraenningsanlaeggningar foer olika typer av braenslen

    Energy Technology Data Exchange (ETDEWEB)

    Eklund, Anders; Rodin, Aasa

    2004-09-01

    major problem. Firing of recovered fuel types resulted in large amounts of fouling. Boilers originally designed for wood fuels are now more and more firing recovered fuel types. However, their soot blowing equipment and their heat absorbing banks are not designed for these large amounts of deposits. Therefore, fouling is a major problem for these boilers. The heat absorbing banks, mainly the superheater and the economizer, can be designed differently regarding to fouling. In general, straight pipes are used in the superheater but with large amount of fouling, the banks are preferably either hanging or standing. In the economizer it is also common to use flanged piping. Hanging straight tubes, horizontal straight tubes are preferably with large amount of fouling and horizontal flanged tubes are used when little amount of fouling is present. The evaluated soot blowing methods have different properties and are used differently. These methods are: Soot blowing with water is mainly used against hard, ceramic-type of deposits formed at high temperatures mainly before the superheater. Soot blowing with steam is commonly used and can be used both in the superheater and the economizer. At higher temperatures and harder deposits, retractable lances with few nozzles are used, while in the economizer with softer types of deposits, fixed and rotational lances with several nozzles is often used. Hammering is mainly used by waste fired boilers with hanging or standing banks and is a successful practise against hard but brittle deposits. Shot cleaning is mainly used in the economizer when the fouling consists of thick, sintered and dry deposits. Acoustic cleaning can be performed with both audible and infra sound. The method is commonly used against softer deposits at lower temperatures or used as a complement to i.e. steam cleaning. Acoustic cleaning is performed much more often than i.e. steam cleaning, and, therefore, it prohibits the formation of a deposit at an early stage

  5. ANALYSIS AND SUMMARY ON TUBE RUPTURE IN THE LOW TEMPERATURE SUPERHEATER OF 85 T/H BOILER%85 T/H 锅炉低温过热器爆管原因分析与总结

    Institute of Scientific and Technical Information of China (English)

    任燕军

    2014-01-01

    文章对广州钢铁控股有限公司85t/h锅炉一级过热器管爆管的原因进行了分析,找出原因,并提出了相应的解决措施,以求对今后的锅炉检修维护工作有所借鉴。%This paper analyzes the cause of tube rupture in the low temperature superheater of 85t/h boiler in the company , tries to find out the reasons and point out the settlement method in order to provide reference for boiler maintenance work in the future .

  6. The Main Form and Inspection Experience Influencing Boiler"Four Tube"Leakage%影响锅炉“四管”泄漏的主要形式及检查经验

    Institute of Scientific and Technical Information of China (English)

    李勇

    2015-01-01

    锅炉“四管”的状况,直接与发电机组的安全、稳定息息相关。锅炉一旦发生“四管”泄漏,只有采取被迫停运,增加了电厂的临时性检修,给发电厂造成很大的经济损失。锅炉紧急停炉抢修不仅打乱了电厂的正常发电秩序,减少了发电量,而且增加了工人的劳动强度和额外的检修费用,同时也干扰了电网系统的正常调度,造成了巨大的经济损失。本文简述了“四管”泄漏的主要形式,并结合洛河电厂历年来出现的“四管”泄漏现象,提出了锅炉“四管”的检查经验。%The condition of the "four tubes" of boiler is closely and directly related to the security, stability of generating unit. If the"four tube" leakage of boiler happens, the down will be forced adopted to. That increases the temporary repair of power plant, and causes great economic losses for the power plant. The emergency stop and repair of boiler furnace interrupts the normal order of power generation plants, reduces capacity and increases the labor intensity of workers and maintenance costs. At the same time, it also interferes the normal operation of power grid system, causes a huge economic losses. This paper briefly describes the main form of"four tube"leakage. Combined with the "four tube" leakage phenomenon over the years in Luohe power plant, the inspection experience of boiler "four tubes" are put forward.

  7. Fouling in Nanofiltration

    OpenAIRE

    Schaefer, Andrea; Andritsos, N; Karabelas, A.J.; Hoek, E.M.V.; Schneider, R.; Nyström, M

    2004-01-01

    According to Koros et al. [1] fouling is “the process resulting in loss of performance of a membrane due to deposition of suspended or dissolved substances on its external surfaces, at its pore openings, or within its pores”. Fouling is also decribed as flux decline which is irreversible and can only be removed by, for example, chemical cleaning [2]. This is different to flux decline due to solution chemistry effects or concentration polarisation which is described in more detail ...

  8. 关注锅炉爆管就是关注电厂价值--以百万千瓦机组锅炉安装防爆管探讨为例%Focusing on Boiler Tube Leakage is Focusing on Power Plant Value:Taking the Discussion of Installing Explosion Stack in One Million Kilowatts Unit Boiler

    Institute of Scientific and Technical Information of China (English)

    张耀庆

    2014-01-01

    The boiler tube leakage on operation is the most prominent failure in one million kilowatts unit boiler. Combined with the operation practice, this paper deeply analyzes the causes, as well as analyzes the installation process of explosion stack and the parts need attention.%锅炉运行爆管是百万千瓦机组锅炉运行中最突出的故障。本文结合百万千瓦机组锅炉运行实践,深入剖析锅炉运行爆管的原因,同时重点解析防爆管安装流程和需要注意的部位。

  9. Biomass boilers

    OpenAIRE

    Nahodil, Jiří

    2011-01-01

    Bachelor’s thesis deals with the use of biomass for heating houses and apartment houses. The first part is dedicated to biomass. Here are mentioned the possibility of energy recovery, treatment and transformation of biomass into a form suitable for burning, its properties and combustion process itself. The second part is devoted to biomass boilers, their separation and description. The last section compares the specific biomass boiler with a boiler to natural gas, particularly from an economi...

  10. 生物质燃料锅炉20G钢低温过热器管爆裂失效分析%Burst failure analysis on 20G steel low temperature superheater tube of biomass-fired boiler

    Institute of Scientific and Technical Information of China (English)

    卿辉; 任耀剑; 孙智

    2014-01-01

    Reason for the failure of low temperature superheater tube of biomass-fired boiler during working was analyzed .The results show that the tube burst is related to the ash of biomass fuel and many short-terms over-high temperature .The alkali chloride and sulfide of the ash of biomass fuel accelerated corrosion and oxides generated , and the tube undergone short-term over-temperature repeatedly .Over-temperature caused pearlitic spheroidization and decreased strength of the material in the meantime .The tube cracking was due to the tube wall thinned by oxide abscission , and could not resist the boiler pressure .%某生物质燃料锅炉低温过热器管在运行中爆裂,对其失效原因进行了分析。结果表明,爆管的原因与生物质燃料灰分和多次短时超温有关。燃料灰分中的碱金属氯化物、硫化物使腐蚀加速,形成氧化物的速度加快,并使管道经历多次短时超温。超温造成组织中珠光体球化,使材料强度下降。氧化物脱落后,管壁的实际壁厚减薄,不足以承受管中的压力导致爆裂。

  11. Titanium condenser tubes

    International Nuclear Information System (INIS)

    The corrosion resistance of titanium in sea water is extremely excellent, but titanium tubes are expensive, and the copper alloy tubes resistant in polluted sea water were developed, therefore they were not used practically. In 1970, ammonia attack was found on the copper alloy tubes in the air-cooled portion of condensers, and titanium tubes have been used as the countermeasure. As the result of the use, the galvanic attack an copper alloy tube plates with titanium tubes as cathode and the hydrogen absorption at titanium tube ends owing to excess electrolytic protection were observed, but the corrosion resistance of titanium tubes was perfect. These problems can be controlled by the application of proper electrolytic protection. The condensers with all titanium tubes adopted recently in USA are intended to realize perfectly no-leak condensers as the countermeasure to the corrosion in steam generators of PWR plants. Regarding large condensers of nowadays, three problems are pointed out, namely the vibration of condenser tubes, the method of joining tubes and tube plates, and the tubes of no coolant leak. These three problems in case of titanium tubes were studied, and the problem of the fouling of tubes was also examined. The intervals of supporting plates for titanium tubes should be narrowed. The joining of titanium tubes and titanium tube plates by welding is feasible and promising. The cleaning with sponge balls is effective to control fouling. (Kako, I.)

  12. 硫磺回收装置余热锅炉过热器弯头开裂原因初步分析%Preliminary Analysis on Tube Cracking Cause of Waste Heat Boiler Superheater of the Sulfur Recovery Unit

    Institute of Scientific and Technical Information of China (English)

    李玉军; 蒋仕良

    2011-01-01

    Refinery sulfur recovery unit plays an important role in the entire production system, and the waste heat boiler superheater is the key component of the device. Because the condition is demanding and complex,the case of superheater elbow cracking was once reported. Through the comprehensive examina-tion and test on the macroscopic test about Elbow cracking parts, thickness measurement, spectrum anal-ysis , metallographic examination, hardness testing and chemical components analysis of stove ash fouling etc, the cause of cracking and the impact of the waste heat boiler superheater and its safe operation was analyzed, then the corresponding prevention and control measure is proposed.%炼化企业硫磺回收装置在整个生产系统中起着重要作用,而余热锅炉过热器是装置的关键组成部分,由于工况苛刻且较为复杂,曾有过热器弯头开裂案例报导,通过对弯头开裂部位宏观检查、测厚、光谱分析、金相检验、硬度测定及炉灰垢样化学成分分析等方面综合检验检测,分析了开裂的产生原因及其对余热锅炉过热器安全运行的影响,并提出了相应的预防与控制措施.

  13. Power for the industrial age: a brief history of boilers

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, S.E.

    1996-02-01

    Boilers were first designed in Greece during the Hellenistic period by Hero, but they were regarded purely as a novelty and no industrial application was found for these toys until the seventeenth century when mining engineers used them for steam-powered pumps. By the end of the 17th century the early shell boilers were replaced by tube boilers, the direct ancestors of the modern boiler. Among the best known of the early boiler manufacturers was Babcock and Wilcox, and they supplied boilers to one of the first electric power plants. In the early 20th century superheaters, economizers, stokers and pulverizers were added to the design of the utility boiler. Fusion-welded boiler drums added to safety. More recently environmental concerns have initiated a new generation of boilers, such as the pressurised fluidised bed combustion boilers and their advanced versions. 5 refs., 3 figs.

  14. 油田热电厂注汽锅炉炉管腐蚀因素分析与控制措施%Corrosion Factors Analysis and Control Measures of Boiler Tubes in Steam In?jection Boiler in the Oilfield

    Institute of Scientific and Technical Information of China (English)

    周登印

    2016-01-01

    The steam injection boiler furnace tube of Daqing oilfield thermal power plant is in high temperature, high pressure and other harsh environmental conditions. The corrosion types are mainly alkali corrosion,dissolved oxygen corrosion,cavitation erosion,steam wa-ter corrosion and stop furnace corrosion. The corrosion factors produced by the medium mainly include temperature, flow rate and water treatment quality. The dissolved oxygen in the oxygen, and the boiler water in the steam injection boiler furnace, that have accelerated the corrosion rate of the furnace tubes. On the basis of corrosion factors targeted research, from the control of boiler feed water quality, reduce boiler oxygen exposure probability and improve the furnace pipe anti-corrosion properties of the essence, four aspects:the use of science and technology,and puts forward the corresponding control measures,aiming to de-lay and reduce the corrosion of all aspects, to prevent corrosion of the probability of more than 99.9%. By controlling the water quality of boiler and reducing the chance of contact with oxygen,the corrosion of boiler tubes is reduced.%大庆油田热电厂注汽锅炉炉管处于高温、高压的恶劣环境工况,腐蚀严重,其腐蚀类型主要为碱腐蚀、溶解氧腐蚀、气蚀、汽水腐蚀和停炉腐蚀.由介质产生的腐蚀因素主要有温度、流速及水处理质量;注汽锅炉炉管中存在的氧气以及锅炉水中溶解的氧加速了炉管腐蚀速率.为延缓腐蚀并减小腐蚀程度,提出以下对应的控制措施:严把水质源头管控,杜绝出现不达标水质进入锅炉;完善运行参数,防止超温、超压环境出现;将多种除氧方法结合使用,以达到最佳除氧效果.停炉后采用TH901法在炉管表面形成保护膜以隔离氧气,该保护法加药量少,成本低,阻止腐蚀的概率达到99.9%以上.通过控制锅炉给水水质,减少锅炉接触氧几率等措施,减缓了注汽锅炉炉管的腐蚀.

  15. Impact of fouling on UV effectiveness

    Energy Technology Data Exchange (ETDEWEB)

    Dykstra, T.S. [Dalhouse Univ., Dept. of Civil Engineering, Halifax, Nova Scotia (Canada); Chauret, C. [Indiana Univ. Kokomo, Kokomo, Biological and Physical Sciences, Indiana (United States)

    2002-06-15

    In recent years ultraviolet light has gained in popularity as an attractive disinfection alternative due to its ability to inactivate bacteria and viruses. UV light has the potential to inactivate Cryptosporidium parvum and Giardia lamblia with a very low potential for the formation of harmful disinfection by-products. Previous studies have reported that particulate material present in the water can act to reduce the exposure of UV light to the receiving waters and that the interference of organic particles can serve to protect bacteria and viruses from intended disinfection. Disinfection capacity can also be reduced by organics in the source water that can accumulate on the surface of quartz sleeves. The purpose of this study was to determine the ability of a medium pressure UV light, at drinking water treatment levels, to inactivate MS 2 bacteriophage after a quartz tube has been fouled with organic rich source water for a 12- week period. To this end the inactivation of MS 2 was determined under clean and fouled conditions, in the presence and absence of humic rich water. The effect of lamp age on inactivation was also investigated. The results suggest that organic fouling of a quartz tube has a significant impact on the disinfection capacity of a medium pressure UV lamp. The presence of organics in the source water also plays a significant role in reducing the capacity of UV for bacterial and viral disinfection. Lamp age also seems to have some effect on the efficiency of UV disinfection. (author)

  16. 46 CFR 56.50-30 - Boiler feed piping.

    Science.gov (United States)

    2010-10-01

    ... for water tube boilers shall have fresh water connections only. Care shall be taken to prevent the... 46 Shipping 2 2010-10-01 2010-10-01 false Boiler feed piping. 56.50-30 Section 56.50-30 Shipping... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-30 Boiler feed piping. (a)...

  17. Experimental Research on Anti-fouling of Heat Exchange Tube under Pulsating Flow%脉动流下热交换圆管抑垢实验研究

    Institute of Scientific and Technical Information of China (English)

    郑小涛; 徐成; 喻九阳; 刘利军; 林纬

    2013-01-01

    A mean of experimental system was set up to test fouling, and use fouling resistance method compared pulsating flow with steady-state flow to research the fouling growth characteristics in pipe. The results showed that with increased frequency of pulse flow, the induce period became longer and the deposition growth rate slowed down. Fouling resistance decreased by 25 percent compared with that of the steady-state when the frequency of pulsating flow was 2 Hz and has obvious effect of restrain fouling.%建立污垢测试实验系统,采用污垢热阻法研究了脉动流和稳态流下光管内的污垢生长特性.实验结果表明,随着脉动流频率增加,污垢生长的诱导期延长,污垢生长速率减慢.当脉动流频率为2.0 Hz时,污垢的渐进热阻值较稳态流时减小25%,具有明显的阻垢效果.

  18. 超超临界机组锅炉末级过热器爆管原因分析%Cause Analysis on Bursting of Final Superheater Tubes of a Ultra Supercritical Boiler

    Institute of Scientific and Technical Information of China (English)

    肖国华; 李益民; 王理博

    2011-01-01

    The bursting and leakage reason of final superheater T91 steel tubes of a ultra super critical boiler was analyzed through chemical compositions analysis, microstructure analysis and mechanical properties test. The results show that the failure of the final superheater tubes was due to overheat which deteriorated the microstructure and mechanical properties of the tubes material. It was believable that the overheat of the bursting tubes was caused by blockage, according to the analysis results on the spot.%通过化学成分分析、金相检验、力学性能测试等手段对某电厂超超临界锅炉末级过热器T91钢管爆裂原因进行了分析.结果表明:爆管系超温运行所致,过热导致钢管材料显微组织老化、力学性能显著下降;并根据现场情况对爆裂管的超温原因进行了分析,认为异物堵塞造成超温的可能性较大.

  19. Mixed salt crystallisation fouling

    CERN Document Server

    Helalizadeh, A

    2002-01-01

    The main purpose of this investigation was to study the mechanisms of mixed salt crystallisation fouling on heat transfer surfaces during convective heat transfer and sub-cooled flow boiling conditions. To-date no investigations on the effects of operating parameters on the deposition of mixtures of calcium sulphate and calcium carbonate, which are the most common constituents of scales formed on heat transfer surfaces, have been reported. As part of this research project, a substantial number of experiments were performed to determine the mechanisms controlling deposition. Fluid velocity, heat flux, surface and bulk temperatures, concentration of the solution, ionic strength, pressure and heat transfer surface material were varied systematically. After clarification of the effect of these parameters on the deposition process, the results of these experiments were used to develop a mechanistic model for prediction of fouling resistances, caused by crystallisation of mixed salts, under convective heat transfer...

  20. 锅炉水冷壁管氢腐蚀爆管原因分析%Cause Analysis of Hydrogen Corrosion Induced Bursting of Waterwall Tubes in a Boiler

    Institute of Scientific and Technical Information of China (English)

    张亚明; 夏邦杰; 董爱华

    2012-01-01

    某热电厂5号锅炉水冷壁发生爆管.对取样水冷壁管进行了宏观观察、化学分析、金相分析、扫描电镜与电子能谱分析及x射线衍射分析等.结果表明,爆管原因是水冷壁管向火侧内壁局部区域发生氢腐蚀所致.提出了预防此类事故发生的措施.%Bursting failure occurred on waterwall tubes of No.5 boiler in a power plant. Macroscop- ic inspection, chemical analysis, metallurgraphy, scanning electron microscopy (SEM), energy dis-persive spectroscopy (EDS) and X-ray diffraction (XRD) were adopted to examine the failed tube. The results indicated that the tube rupture was resulted from localized hydrogen corrosion of the part facing fire. Preventive measures of such failures are put forward.

  1. Slagging and Fouling Characteristics of HRSG for Ferrosilicon Electric Furnaces

    Directory of Open Access Journals (Sweden)

    Yungang Wang

    2015-02-01

    Full Text Available The slagging and fouling characteristics of the heat recovery steam generator (HRSG for ferrosilicon electric furnaces are discussed in this paper. Three ash samples were taken from the HRSG of a ferrosilicon furnace in Ningxia Province, China, which suffered from serious slagging and fouling. X-ray fluorescence (XRF, X-ray powder diffraction (XRD and scanning electron microscope (SEM were used to analyze the ash samples. The results show that low melting point salt Na2SO4 and composite salts Na (AlSi3O8 and 3K2SO4·CaSO4 deposit on the superheater tube walls in aerosol form and solidify to form the initial slag layer. With the continuous deposition of the low melting point compounds, more and more ash particles in the flue gas adhere to the slag surface to form a thicker slag. Low melting point composite salt NaO·Al2O3·SiO2 is absorbed on the evaporator tube walls in aerosol form. With the deposition of NaO·Al2O3·SiO2, more and more ash particles are absorbed to form the fouling. Since there is less space between pin-finned tubes, the large iron-rich slag particles are easily deposited on tube walls and fin surfaces, which is advantageous to the fouling process. There are large quantities of superfine ash particles in the flue gas that easily adhere to other particles or tube walls, which facilitates the slagging and fouling process.

  2. 锅炉管高频熔覆温度场的数值模拟%Numerical simulation on temperature field of boiler tube coating fabricated by high frequency induction cladding

    Institute of Scientific and Technical Information of China (English)

    岑虎; 王云山; 雷剑波; 孟庆若; 刘少军

    2013-01-01

    Induction heating and Fourier heat conduction principles were used to simulate the temperature field of the boiler tube and alloy layer. The changing law of the temperature field under different cladding parameters was researched, and the cladding experiments were carried out on the surface of the boiler tube. The results show that the efficiency of the induction cladding is mainly influenced by power frequency and electric current. The heating rate of the boiler tube’s surface increases with increasing power frequency of induction power source or electric current of cladding. When high frequency cladding process is fixed, the lower the temperature of tube’s inwall is, the less the heating affect on base material is. When the power frequency is 250 kHz and electric current is 1 180 A, the transitional zone exits in the zone between the cladding layer and the matrix and forms metallurgical bouding.%应用感应加热原理和傅立叶导热定律对高频熔覆中锅炉管壁和合金层的温度场进行模拟计算,分析不同熔覆参数下锅炉管及合金层温度场随时间的变化规律;并对锅炉管表面进行熔覆实验研究。结果表明,在熔覆工作头和管的结构及参数给定的条件下,感应加热速度主要受高频感应加热电源频率和熔覆电流的影响。在一定范围内,感应加热电源的频率越高,或熔覆电流越大,则锅炉管表面升温速度越快,熔覆结束时管内壁温度越低,基体受热影响越小;当频率为250 kHz、熔覆电流为1180 A时,熔覆层与基体间有明显的白亮过渡带,形成了冶金结合。

  3. Optimal scheduling of sootblowers in power plant boilers

    Science.gov (United States)

    Vasquez-Urbano, Pedro Manuel

    1997-11-01

    Burning coal or other fossil fuels in a utility boiler fouls the surfaces of its heat exchangers with ash and soot residues. These deposits affect the performance of the power plant since they reduce heat transfer from the combustion gases to the water or steam. Fouling can be removed during the operation of the plant with the use of lances, called sootblowers, that direct high-pressure air or steam onto the fouled surfaces. Sootblowing operations are key to plant efficiency and boiler maintenance, but they also incur operating costs. A utility boiler may have a hundred or so sootblowers placed in fixed locations. Deciding which of these should be used at any moment is complicated by the lack of instrumentation that can monitor fouling levels. This dissertation studies the optimization problem of scheduling sootblowing activities at a utility plant. The objective is to develop an optimization approach to determine which sootblowers should be activated at any moment in order to maximize plant efficiency. To accomplish this, three issues are addressed. First, models are developed that can estimate fouling conditions indirectly during plant operation using commonly available data. The approach used relies on a sequential application of linear regression fits. Secondly, autoregressive exogenous (ARX) models are used to describe the dynamics of the fouling process and to estimate the consequences of fouling on plant efficiency. All the foregoing empirical models are developed using data from a power plant. Finally, using the empirical models, an optimization model is formulated for the sootblowing scheduling problem and different optimization approaches that combine nonlinear programming with heuristics methods are investigated for its solution. The applicability of dynamic programming to this optimization problem is also explored.

  4. Life extension of boilers using weld overlay protection

    Energy Technology Data Exchange (ETDEWEB)

    Lai, G.; Hulsizer, P. [Welding Services Inc., Norcross, GA (United States); Brooks, R. [Welding Services Inc., Welding Services Europe, Spijkenisse (Netherlands)

    1998-12-31

    The presentation describes the status of modern weld overlay technology for refurbishment, upgrading and life extension of boilers. The approaches to life extension of boilers include field overlay application, shop-fabricated panels for replacement of the worn, corroded waterwall and shop-fabricated overlay tubing for replacement of individual tubes in superheaters, generating banks and other areas. The characteristics of weld overlay products are briefly described. Also discussed are successful applications of various corrosion-resistant overlays for life extension of boiler tubes in waste-to-energy boilers, coal-fired boilers and chemical recovery boilers. Types of corrosion and selection of weld overlay alloys in these systems are also discussed. (orig.) 14 refs.

  5. The structure and behavior of salts in kraft recovery boilers

    Energy Technology Data Exchange (ETDEWEB)

    Backman, R.; Badoi, R.D.; Enestam, S. [Aabo Akademi Univ., Turku (Finland). Combustion Chemistry Research Group

    1997-10-01

    The melting behavior in the salt system (Na,K)(CO{sub 3},SO{sub 4},S,Cl,OH) is investigated by laboratory methods to enhance and further develop a chemical model for salt mixtures with compositions relevant for recovery boilers. The model, based on both literature data and experimental work can be used as (a) submodel in models for the over-all chemistry in recovery boilers and to estimate (b) deposit formation on heat transfer surfaces (fouling), (c) the melting properties of the fly ash, and (d) the smelt bed in recovery boilers. Experimental techniques used are thermal analysis, high temperature microscopy` and scanning electron microscopy. The model is implemented in a global calculation model which can handle both gas phases and condensed phases in the recovery boiler. The model gives a detailed description of the chemical reactions involved in the fume and dust formation in different locations of the flue gas channel in the boiler. (orig.)

  6. Analog-experiment analysis of ash-deposition monitoring model of boiler economizers in power plants

    Institute of Scientific and Technical Information of China (English)

    CHENG Wei-liang; XIA Guo-dong; XU Shou-chen

    2005-01-01

    Ash deposition is a form of particulate fouling, and appears usually in boiler economizers. The ash deposition increases capital expenditure, energy input and maintenance costs. An analog experiment for monitoring ash deposition was performed from the analogous objective of a 410 t/h boiler economizer to verify the rationality and reliability of the ash-deposition-monitoring model presented in order to increase the security and economy in economizer running. The analog experiment platform is a tube-shell exchanger that conforms well to the conditions of a self-modeling area. The analog flue gas in the shell side is the heated air mixed with ash,and in the tube side the fluid is water heated by the flue gas. The fluid state in the water side and the flue gas side follows the second self-modeling area. A 4-factor-3 level orthogonal table was used to schedule 9 operation conditions of orthogonal experiment, with the 4 factors being heat power, flue gas velocity, ashes grain diameter and adding ashes quantity while the three levels are different values due to different position classes in every factor. The ash deposition thermal resistances is calculated by the model with the measure parameters of temperature and pressure drop. It shows that the values of the ash deposition thermal resistances gradually increase up to a stable state. And the experimental results are reliable by F testing method at α = 0. 001. Therefore, the model can be applied in online monitoring of ash deposition in a boiler economizers in power plants and provides scientific decision on ash deposition prediction and sootblowing.

  7. Effect of Water Quality on the Performance of Boiler in Nigerian Petroleum Industry

    OpenAIRE

    J. O. ODIGURE; A. S. ABDULKAREEM; E. T. ASUQUO

    2005-01-01

    This work investigates quality of water used in boilers of Refinery Company in Nigeria. The results shows that the quality of water fed to boilers are off specification. Low water quality used in boilers led to frequent failure of the boilers as a result of tube rupture. This has resulted into low capacity utilization and loss of processing fees. The poor performance of the boiler feed treatment plant is attributable to the deplorable condition of water intake plant, raw water treatment, demi...

  8. 46 CFR 52.15-5 - Tube connections (modifies PWT-9 and PWT-11).

    Science.gov (United States)

    2010-10-01

    ... BOILERS Requirements for Watertube Boilers § 52.15-5 Tube connections (modifies PWT-9 and PWT-11). (a... of section I of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 52.01... tubes shall not be permitted as described by PWT-9.2 and PWT-11.3 of section I of the ASME Boiler...

  9. Steam generators and waste heat boilers for process and plant engineers

    CERN Document Server

    Ganapathy, V

    2014-01-01

    Incorporates Worked-Out Real-World ProblemsSteam Generators and Waste Heat Boilers: For Process and Plant Engineers focuses on the thermal design and performance aspects of steam generators, HRSGs and fire tube, water tube waste heat boilers including air heaters, and condensing economizers. Over 120 real-life problems are fully worked out which will help plant engineers in evaluating new boilers or making modifications to existing boiler components without assistance from boiler suppliers. The book examines recent trends and developments in boiler design and technology and presents novel idea

  10. Experimental Study on Under-deposit Corrosion of Water Wall Tube in a 420t Utility Boiler%一台420t电站锅炉水冷壁管垢下腐蚀试验研究

    Institute of Scientific and Technical Information of China (English)

    李勇; 赵彦杰; 欧俊

    2015-01-01

    在对某电厂一台420t电站锅炉检验过程中,发现该锅炉水冷壁管存在结垢现象,水冷壁管垢下腐蚀会对锅炉的安全、经济运行造成影响。通过均匀腐蚀失效试验、氢脆腐蚀失效试验确定其腐蚀原理,并对其腐蚀速率进行了研究。%There were two under-deposit corrosion forming causes, uniform corrosion and hydrogen corrosion. In the inspection of a 420t/h utility boiler, scaling was found in its water wall tube leading to the temperature difference between different sides of water wall tube. The safety and economy will be affected. Through theory and experiment, corrosion mechanism and prevention measures were presented in this paper.

  11. Boiler corrosion. Corrosion of boilers at low boiler water temperatures. Heizkessel-Korrosion. Korrosion von Heizkesseln bei tiefen Kesselwassertemperaturen

    Energy Technology Data Exchange (ETDEWEB)

    Koebel, M.; Elsener, M.

    1989-02-01

    Thermostatic cast iron and steel 35.8 specimens were inserted between the fire tubes of a test boiler and exposed to flue gases for a period of three weeks. The corrosion rates at material temperatures between 20 and 60deg C as well as the effects of continuous and intermittent boiler operation were determined. Details are given on the specimens alloying constituents, the testing and test conditions (schematic representation of the experimental set-up). Diagrams and tables facilitate access to test results informing about corrosion rates and corrosion product structure analyses for continuous burner operation. While low boiler water temperatures (below 60deg C in the case of extra light heating oils) are found to necessarily involve higher risks and shorter boiler service lives, low flue gas temperatures alone are considered not to be increasing the risk of boiler corrosion. (HWJ).

  12. Influence of Heat Flux and Friction Coefficient on Thermal Stresses in Risers of Drum Boilers under Dynamic Conditions of Steam Demand

    OpenAIRE

    Habib, M.A; Alzaharnah, I.; El-Shafei, M.; N. Merah; S. Al-Anizi; Al-Awwad, M. Y.; M. Hajji

    2013-01-01

    Boiler swing rate, which is the rate at which the boiler load is changed, has significant influence on the parameters of the boiler operating conditions such as drum water pressure and level, steam quality in the riser tubes, wall temperatures of riser tubes, and the associated thermal stresses. In this paper, the thermal stresses developed in boiler tubes due to elevated rates of heat transfer and friction are presented versus thermal stresses developed in tubes operated under normal conditi...

  13. Inert tube coatings as a method to reduce deposit adhesion on superheaters; Inerta tubytbelaeggningar som metod att minska paaslagens vidhaeftning paa oeverhettare

    Energy Technology Data Exchange (ETDEWEB)

    Almark, Matts; Staalenheim, Annika; Henderson, Pamela

    2007-12-15

    In many biofuel and waste fired boilers there are significant deposit related problems. The fouling of the superheaters and other heat transfer surfaces reduces the heat transfer, which leads to increased flue gas temperatures, or might block the entire flue gas channel in extreme cases. An increasing share of waste and refuse derived fuels as well as the use of new types of biomass have led to increased problems with deposit formation. In order to minimize the formation of deposits and to maintain low flue gas temperatures the superheaters are subjected to frequent soot blowing, which in turn may lead to increased material loss of the tubes. The purpose of this project is to try to show that tube surfaces that may be regarded as inert have a 'non-stick' effect and that the fouling is reduced when the deposits do not react with the tube surface layer, and the adhesive force of the deposits are reduced. Nickel based alloy Sanicro 63, which forms a nickel oxide surface layer, and Kanthal APM, which forms an aluminum oxide surface layer, are compared with 15Mo3, a common superheater steels forming iron oxide and Sanicro 28, a stainless steel which forms iron and chromium oxides. Applied coatings are also tested, welded Alloy 625 and sprayed Kanthal APM, in order to investigate how ht application method interferes with the results from the pure material. A ceramic coating material that is claimed to give good results in waste and coal fired boilers is also tested. Tests with cooled probes, on which the tested materials are mounted, are performed in two different boilers, Haendeloe P14 representing waste fired boilers with fouling issues related to chlorine and heavy metals, and Myllykoski K7 representing a forest industry with non-corrosive sulfate containing deposits. The results show that a tube surface of a nickel-based alloy can reduce the formation of chlorine rich, partly melted deposits. No effect was shown on the dry, chlorine-free deposits. The

  14. Pulse shear stress for anaerobic membrane bioreactor fouling control.

    Science.gov (United States)

    Yang, Jixiang; Spanjers, Henri; van Lier, Jules B

    2011-01-01

    Increase of shear stress at membrane surfaces is a generally applied strategy to minimize membrane fouling. It has been reported that a two-phase flow, better known as slug flow, is an effective way to increase shear stress. Hence, slug flow was introduced into an anaerobic membrane bioreactor for membrane fouling control. Anaerobic suspended sludge was cultured in an anaerobic membrane bioreactor (AMBR) operated with a side stream inside-out tubular membrane unit applying sustainable flux flow regimes. The averaged particle diameter decreased from 20 to 5 microm during operation of the AMBR. However, the COD removal efficiency did not show any significant deterioration, whereas the specific methanogenic activity (SMA) increased from 0.16 to 0.41 gCOD/g VSS/day. Nevertheless, the imposed gas slug appeared to be insufficient for adequate fouling control, resulting in rapidly increasing trans membrane pressures (TMP) operating at a flux exceeding 16 L/m2/h. Addition of powdered activated carbon (PAC) enhanced the effect of slug flow on membrane fouling. However, the combined effect was still considered as not being significant. The tubular membrane was subsequently equipped with inert inserts for creating a locally increased shear stress for enhanced fouling control. Results show an increase in the membrane flux from 16 L/m2/h to 34 L/m2/h after the inserts were mounted in the membrane tube. PMID:22097007

  15. A Discussion on the Design of Flue Type Waste Heat Boiler with“Double Longitudinal Drum + Convection Tube Bundle”%“双纵锅筒+对流管束”烟道式余热锅炉的设计探讨

    Institute of Scientific and Technical Information of China (English)

    何上俊

    2015-01-01

    介绍了“双纵锅筒垣对流管束”烟道式余热锅炉的结构特点,着重分析了热力计算,提出了不同于JB/T 7603-94《烟道式余热锅炉设计导则》的烟气侧放热量的计算式,说明了锅炉的运行特点。%The structural characteristics of the flue type waste heat boiler with“double longitudinal drum + convection tube bundle”are introduced, the thermodynamic calculation is emphatically analyzed, a calculation formula of heat release on the flue gas side different from the JB/T 7603-94 Flue Type Waste Heat Boiler Design Guideline is put forward and operation characteristics of the boiler are described.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, William (Sandy) [SharpConsultant

    2011-12-01

    the measured first melting point of fly ash deposits does not necessarily produce a step increase in corrosion rate. Corrosion rate typically accelerates at temperatures below the first melting temperature and mixed deposits may have a broad melting temperature range. Although the environment at a superheater tube surface is initially that of the ash deposits, this chemistry typically changes as the deposits mature. The corrosion rate is controlled by the environment and temperature at the tube surface, which can only be measured indirectly. Some results are counter-intuitive. Two boiler manufacturers and a consortium have developed models to predict fouling and corrosion in biomass boilers in order to specify tube materials for particular operating conditions. It would be very useful to compare the predictions of these models regarding corrosion rates and recommended alloys in the boiler environments where field tests will be performed in the current program. Manufacturers of biomass boilers have concluded that it is more cost-effective to restrict steam temperatures, to co-fire biofuels with high sulfur fuels and/or to use fuel additives rather than try to increase fuel efficiency by operating with superheater tube temperatures above melting temperature of fly ash deposits. Similar strategies have been developed for coal fired and waste-fired boilers. Additives are primarily used to replace alkali metal chloride deposits with higher melting temperature and less corrosive alkali metal sulfate or alkali aluminum silicate deposits. Design modifications that have been shown to control superheater corrosion include adding a radiant pass (empty chamber) between the furnace and the superheater, installing cool tubes immediately upstream of the superheater to trap high chloride deposits, designing superheater banks for quick replacement, using an external superheater that burns a less corrosive biomass fuel, moving circulating fluidized bed (CFB) superheaters from the

  17. Investigations on the fouling behaviour of Rhenish brown coals in lignite-fired power plants

    International Nuclear Information System (INIS)

    In lignite-fired power plants high fouling in heat exchangers can be observed while firing Rhenish brown coals rich in sodium and poor in silicon content. These sulphatic and oxidic deposits reduce the heat transfer and can cause plant damage. It is assumed that fouling is caused by ash softening and partial melting of alkaline phases. The objective of this dissertation is to provide a better understanding of the fouling processes in lignite-fired boilers through experimental analysis using the ashes of different Rhenish brown coals and synthetic ash mixtures. In order to estimate the agglomeration potential of the brown coal ashes and synthetic ash mixtures, measurements of shear properties and impedance spectroscopy were performed. Furthermore, exposure tests in air and flue gas were conducted in the temperature range between 600 to 1,200 C to evaluate the influence of different parameters on the crystalline phase compounds and microstructures of the brown coal ashes and synthetic ash mixtures. The exposed samples were compared among each other and with corresponding ash deposits produced in a micro combustion chamber. Another aim of this dissertation is to verify the occurrence of NaOH melt in fouling processes. For this purpose impedance spectroscopy with a special probe was performed in the pilot power plant Niederaussem while firing sodium enriched fouling coal. This research indicates the importance of non-silicate bonded sodium and calcium in fouling processes. The higher their contents are, the higher is the fouling potential of the brown coal. Although the occurrence of NaOH in the boiler can not be directly proven by impedance spectroscopy, the experimental results indicate that it plays an important role in fouling. However, this research shows that silicates reduce the fouling potential of the ashes. Shear property measurements, impedance spectroscopy and the calculation of Na/Si and Ca/Si ratios of 450 C-ashes are applicable methods to predict the

  18. 超临界锅炉末级过热器爆管原因的分析%Burst Cause Analysis of Final-stage Superheater Tubes for a Supercritic al Boiler

    Institute of Scientific and Technical Information of China (English)

    赵慧传; 贾建民; 陈吉刚; 梁军; 杨红权; 尹成武

    2011-01-01

    为研究超临界锅炉末级过热器爆管的原因,对1台600MW超临界锅炉末级过热器爆管上游管和相关管样的内壁氧化物的宏观形态、微观结构,脱落氧化皮的微观结构、物相、各区域的微观形态和成分等进行了分析.结果表明:堵塞末级过热器下弯头造成过热器爆管的脱落氧化皮来自于T23/T91钢管的T23管段内壁,而非T91管段内壁;T23钢管内壁氧化皮为二层结构,外层为粗大柱状晶的纯磁铁矿(Fe3O4),内层为等轴细晶的含W和Cr的尖晶石;原生氧化皮内层存在一条或多条沿圆周方向排列的孔洞链,氧化皮容易沿孔洞链分离,从而造成氧化皮脱落.%In order to find the causes of tube burst failures encountered by the final-stage superheater of a 600 MW supercritical boiler, an analysis was carried out to both macrostructure and microstructure of the oxide scales taken from inner surface of relevant tube samples, and to the microstructure, phase, micromorphology and composition of fall-off scales. Results show that the failure has been caused by oxide scales split off from inner surface at T23 side of the T23/T91 joint, which blocked the lower elbow of the superheater and finally led to the tube burst. The scale on inner surface of T23 tube has a two-layer structure, of which the outer layer is the coarse columnar grain Fe3 O4 while the inner layer fine equiaxed spinel,containing W and Cr element. One or more hole-chains on inner surface of primitive oxide skin formed along the circumference direction are easy to break and cause the oxide skin to fall off.

  19. Failure Analysis of Low Temperature Superheater Tube of Utility Boiler%电站锅炉低温过热器管失效分析

    Institute of Scientific and Technical Information of China (English)

    周经伟; 周荣稳

    2013-01-01

      Through making the failure analysis on low temperature superheater tube by employing the related technological means, the paper determines the cause of failure and puts preventive measures to avoid and prevent similar incidents from happening again.%  通过对低温过热器爆管,采用相关的技术手段进行失效情况分析,确定失效的原因,提出预防措施,避免和防止同类事故的再次发生。

  20. 超超临界锅炉小径管焊缝的超声相控阵检测工艺%Ultrasonic Phased Array Testing for Small Diameter Tube Weld of Ultra-supercritical Boiler

    Institute of Scientific and Technical Information of China (English)

    王维东; 王亦民; 孟倩倩; 曹云峰; 张振华

    2015-01-01

    A series of ultrasonic phased array inspection contrast test blocks were developed according to the distribution range of the boiler pipe weld defect,and at the same time tests were conducted on the simulation and natural defects,respectively.By making distance amplitude curve for 1 mm diameter horizontal hole,we quantified and measured indicating length of defects both inside and outside of the tube with different diameter and thickness, and thus corrected the errors of the traditional detection and established the testing method of ultrasonic phased array for small pipe weld.%根据锅炉小径管焊缝的缺陷分布范围,研制出系列超声相控阵检测的对比试块,并进行了模拟与自然缺陷的检测试验。测试采用ϕ1 mm横孔制作距离-波幅曲线,对不同外径与壁厚的内外壁缺陷进行定量与指示长度测定,修正了传统检测的误区,建立了超声相控阵小径管焊缝的检测工艺方法。

  1. Ultrasonic Phased Array Testing for Small Diameter Tube Weld of Ultra-supercritical Boiler%超超临界锅炉小径管焊缝的超声相控阵检测工艺

    Institute of Scientific and Technical Information of China (English)

    王维东; 王亦民; 孟倩倩; 曹云峰; 张振华

    2015-01-01

    根据锅炉小径管焊缝的缺陷分布范围,研制出系列超声相控阵检测的对比试块,并进行了模拟与自然缺陷的检测试验。测试采用ϕ1 mm横孔制作距离-波幅曲线,对不同外径与壁厚的内外壁缺陷进行定量与指示长度测定,修正了传统检测的误区,建立了超声相控阵小径管焊缝的检测工艺方法。%A series of ultrasonic phased array inspection contrast test blocks were developed according to the distribution range of the boiler pipe weld defect,and at the same time tests were conducted on the simulation and natural defects,respectively.By making distance amplitude curve for 1 mm diameter horizontal hole,we quantified and measured indicating length of defects both inside and outside of the tube with different diameter and thickness, and thus corrected the errors of the traditional detection and established the testing method of ultrasonic phased array for small pipe weld.

  2. Steam boiler technology

    Energy Technology Data Exchange (ETDEWEB)

    Teir, S.

    2002-07-01

    The steam boiler technology e-Book is provided by the Laboratory of Energy Engineering and Environmental Protection at Helsinki University of Technology. The book covers the basics and the history of steam generation, modern boilers types and applications, steam/water circulation design, feedwater and steam systems components, heat exchangers in steam boilers, boiler calculations, thermal design of heat exchangers.

  3. Characterization of Oxy-combustion Impacts in Existing Coal-fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Bradley Adams; Andrew Fry; Constance Senior; Hong Shim; Huafeng Wang; Jost Wendt; Christopher Shaddix

    2009-06-30

    This report summarizes Year 1 results of a research program designed to use multi-scale experimental studies and fundamental theoretical models to characterize and predict the impacts of retrofit of existing coal-fired utility boilers for oxy-combustion. Through the course of Year 1 activities, great progress was made toward understanding the issues associated with oxy-combustion retrofit of coal-fired boilers. All four Year 1 milestones and objectives have been, or will be, completed on schedule and within budget. Progress in the four milestone areas may be summarized as follows: • University of Utah has performed size segregated ash composition measurements in the Oxy-Fuel Combustor (OFC). These experiments indicate that oxy-combustion retrofit may impact ash aerosol mineral matter composition. Both flame temperature and flue gas composition have been observed to influence the concentration of calcium, magnesium and iron in the fine particulate. This could in turn impact boiler fouling and slagging. • Sandia National Labs has shown that char oxidation rate is dependent on particle size (for sizes between 60 and 100 microns) by performing fundamental simulations of reacting char particles. These predictions will be verified by making time-resolved optical measurements of char particle temperature, velocity and size in bench-scale experiments before the end of Year 1. • REI and Siemens have completed the design of an oxy-research burner that will be mounted on University of Utah’s pilot-scale furnace, the L1500. This burner will accommodate a wide range of O2, FGR and mixing strategies under conditions relevant for utility boiler operation. Through CFD modeling of the different burner designs, it was determined that the key factor influencing flame stabilization location is particle heat-up rate. The new oxy-research burner and associated equipment is scheduled for delivery before the end of Year 1. • REI has completed a literature survey of slagging and

  4. Tests of a TGM-96 boiler unit at higher than rated load

    Science.gov (United States)

    Kholshchev, V. V.

    2011-09-01

    Results of boiler tests are presented that were carried out at boiler loads up to 1.1 of its rated value, during which the steam superheater's temperature operating conditions were checked, and the parameters characterizing the quality of steam, feedwater, and boiler water were determined. Figures characterizing the longevity of steam superheater tubes are presented that were calculated taking into account the boiler operating mode with a higher-than-nominal load.

  5. Thermal Analysis of Superheater Platen Tubesin Boilers

    Directory of Open Access Journals (Sweden)

    Shahram Falahatkar

    2014-01-01

    Full Text Available Superheaters are among the most important components of boilers and have major importance due to this operation in high temperatures and pressures. Turbines are sensitive to the fluctuation of superheaterstemperature;therefore even the slightest fluctuation in the outlet vapor temperature from the superheaters does damage the turbine axis and fins. Examining the potential damages of combustion in the boilers and components such as the superheaters can have a vital contribution to the progression of the productivity of boiler, turbine and the power plant altogether it solutions are to be fund to improve such systems. In this study, the focus is on the nearest tube set of superheaters to the combustion chamber.These types of tubes are exposed to a wide range ofcombustion flames such that the most heat transfer to them is radiation type.Here, the 320 MW boiler of Isfahan power plant (Iran, the combustion chamber, 16 burners and the platensuperheater tubes were remodeled by CFD technique. The fluid motion, the heat transfer and combustion processes are analyzed. The two-equation turbulence model of k-εis adopted to measure the eddy viscosity. The eddy dissipation model is used to calculate the combustion as well as the P-1 radiation model to quantify the radiation. The overheated zones of superheater tubes and the combustion chamber are identified in order toimprove this problem by applying the radiation thermal shields and knees with porous crust which are introduced as the new techniques.

  6. 49 CFR 214.323 - Foul time.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Foul time. 214.323 Section 214.323 Transportation... TRANSPORTATION RAILROAD WORKPLACE SAFETY Roadway Worker Protection § 214.323 Foul time. Working limits established on controlled track through the use of foul time procedures shall comply with the...

  7. Observation on fouling organisms collected from Indian naval ships at Bombay

    Directory of Open Access Journals (Sweden)

    V. Gopalakrishnan

    1959-01-01

    Full Text Available Fouling organisms collected from Indian Naval Ships dry-docked at Bombay during a period of two years (July 1956-June 1958 were studied in detail. Forty six of the forms collected have been identified. The most important groups of ship-fouling Organisms in Bombay waters are Barnacles, Hydroids, Polyzoans and Tube-worms. Eleven different Fouling Communities have been found to dominate the settlements on the hulls at different occasions. Definite zonations that could be observed were restriction of green algae to the boot-top area and mussels and oysters to the pipes and gratings. An attempt has been made to find the sequence of settlement of the different major fouling groups. Some general remarks on the observations have also been included.

  8. Commercial production practice on steel 12Cr1MoV for boiler tube%锅炉管用钢12Cr1MoV 生产实践

    Institute of Scientific and Technical Information of China (English)

    刘兵; 吕安明; 刘利; 梁艳; 刘超群

    2015-01-01

    The high pressure boiler tube steel 12Cr1MoV was produced with the path of hot metal+scrap → 100 t EAF→double LF→ double VD→ round billet continuous casting(section 650 mm),in the special steel division new district of Laiwu Steel.The difficulties that existed in the actual production of 12Cr1MoV can be overcame with the methods of the reinforcement smelting process,adjusting the refining slag,strengthen protective casting and so on. So the chemical composition,low power structure,non-metallic inclusions rating and other indicators of the 12Cr1MoV meet the customers requirement.%莱钢特钢事业部新区采用铁水+废钢→100 t 电炉→双工位 LF→双工位 VD→圆坯连铸(650 mm)→步进式加热炉→950轧机轧制的流程生产高压锅炉管钢12Cr1MoV,通过优化冶炼工艺、调整精炼渣系、强化保护浇铸等措施,克服了12Cr1MoV 钢在实际生产中的困难,使12Cr1MoV 钢的化学成分、低倍以及非金属夹杂物评级等各项指标均满足用户要求。

  9. Boiler Retrofit for the Utilization of Biodiesel

    Directory of Open Access Journals (Sweden)

    Leily Nurul Komariah

    2016-02-01

    Full Text Available Fuel oil used in the boiler is able to substitute with biodiesel. In lower blends, there are no engine modification needed, but some researchers recommended some technical adjustments in order to maintain the boiler's performance and equipment durability. This study consists of the comparison between the performance of boiler before and after retrofitting on the use of biodiesel. The diesel oil was introduced in biodiesel blends of 10% (B10, 20% (B20 and 25% (B25. A fire tube boiler was used for the test with pressure of 3 bar and heat input capacity of 60,000 kcal. The boiler retrofit is conducted by fine tuning the fan damper scale (FDS and adding a heating feature on fuel system. It was specifically intended to maintain the quality of combustion and boiler efficiency as well as to avoid an increase in fuel consumption. The combustion behaviour was monitored by exhaust emissions of CO, NOx, and SO2. The fan damper scale (FDS and fuel temperature is adjusted by the increasing portion of biodiesel used. The fuel heating apparatus was set at temperature of 40oC for the use of B10, and 60oC for B20 and B25. The FDS adjustment was successfully resulted a reduction in rate of combustion air by average of 9.2%. The boiler retrofitting for the utilization of B10, B20 and B25 showed an increase in boiler efficiency by 0.64%, 0.42% and 2.6% respectively. The boiler retrofitting is surprisingly reduced the fuel consumption by average of 11.2%.

  10. A Rule-Based Industrial Boiler Selection System

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  12. Central heating: package boilers

    Energy Technology Data Exchange (ETDEWEB)

    Farahan, E.

    1977-05-01

    Performance and cost data for electrical and fossil-fired package boilers currently available from manufacturers are provided. Performance characteristics investigated include: unit efficiency, rated capacity, and average expected lifetime of units. Costs are tabulated for equipment and installation of various package boilers. The information supplied in this report will simplify the process of selecting package boilers required for industrial, commercial, and residential applications.

  13. 46 CFR 52.05-45 - Circumferential joints in pipes, tubes and headers (modifies PW-41).

    Science.gov (United States)

    2010-10-01

    ..., tubes and headers shall be as required by PW-41 of section I of the ASME Boiler and Pressure Vessel Code... 46 Shipping 2 2010-10-01 2010-10-01 false Circumferential joints in pipes, tubes and headers...) MARINE ENGINEERING POWER BOILERS Requirements for Boilers Fabricated by Welding §...

  14. Thermo hydraulics of a steam boiler forced circulation

    International Nuclear Information System (INIS)

    In order to minimize the dryout at the steam boiler furnace in the Thermal Power Plant Kolubara B, designed are inner rifled wall tubes. This type of tubes, with many spiral grooves cut into the bore, prevents film boiling and enables the nucleate boiling be still maintained under the condition of vapour quality being app. 1. To verify the choice of the rifled tubes instead of the cheaper, smooth tubes type being justified, analyzed is the change of the actual and critical vapour quality with the furnace height, under uniform and non-uniform heat flu through evaporator walls. Furthermore, made are hydraulic calculations for various steam boiler loads, in case of both rifled and smooth tubes types, with the purpose to check the rifles influence to pressure drop increase in comparison with the smooth tubes. Also, checked is the selection of the circulation pump. Key words: evaporator, forced circulation, rifled tubes, critical vapour quality, pressure drop

  15. Model boiler studies on deposition and corrosion

    International Nuclear Information System (INIS)

    Deposit formation was studied in a model boiler, with sea-water injections to simulate the in-leakage which could occur from sea-water cooled condensers. When All Volatile Treatment (AVT) was used for chemistry control the deposits consisted of the sea-water salts and corrosion products. With sodium phosphate added to the boiler water, the deposits also contained the phosphates derived from the sea-water salts. The deposits were formed in layers of differing compositions. There was no significant corrosion of the Fe-Ni-Cr alloy boiler tube under deposits, either on the open area of the tube or in crevices. However, carbon steel that formed a crevice around the tube was corroded severely when the boiler water did not contain phosphate. The observed corrosion of carbon steel was caused by the presence of acidic, highly concentrated chloride solution produced from the sea-water within the crevice. Results of theoretical calculations of the composition of the concentrated solution are presented. (author)

  16. Asphaltene Aggregation and Fouling Behavior

    Science.gov (United States)

    Derakhshesh, Marzie

    This thesis explored the properties of asphaltene nano-aggregates in crude oil and toluene based solutions and fouling at process furnace temperatures, and the links between these two phenomena. The link between stability of asphaltenes at ambient conditions and fouling at the conditions of a delayed coker furnace, at over 450 °C, was examined by blending crude oil with an aliphatic diluent in different ratios. The stability of the blends were measured using a S-value analyzer, then fouling rates were measured on electrically heated stainless steel 316 wires in an autoclave reactor. The less stable the blend, the greater the rate and extent of fouling. The most severe fouling occurred with the unstable asphaltenes. SEM imaging of the foulant illustrates very different textures, with the structure becoming more porous with lower stability. Under cross-polarized light, the coke shows the presence of mesophase in the foulant layer. These data suggest a correlation between the fouling rate at high temperature furnace conditions and the stability index of the crude oil. Three organic polysulfides were introduced to the crude oil to examine their effect on fouling. The polysulfides are able to reduce coking and carbon monoxide generation in steam crackers. The fouling results demonstrated that polysulfide with more sulfur content increased the amount of corrosion-fouling of the wire. Various additives, solvents, ultrasound, and heat were employed to attempt to completely disaggregate the asphaltene nano-aggregates in solution at room temperature. The primary analytical technique used to monitor the nano-aggregation state of the asphaltenes in solution was the UV-visible spectroscopy. The results indicate that stronger solvents, such as pyridine and quinoline, combined with ionic liquids yield a slight reduction in the apparent absorbance at longer wavelengths, indicative of a decrease in the nano-aggregate size although the magnitude of the decrease is not significant

  17. Development of P22 Tube Blank Steel for High Pressure Boiler Tube%高压锅炉管用P22管坯钢的开发生产

    Institute of Scientific and Technical Information of China (English)

    袁淑君; 李业才

    2016-01-01

    Based on the technology of steel requirements, the chemical composition and internal control requirements of the steel were designed. Using clean steel technology to control S, P and inclusion, selecting high-quality scrap and molten iron to control As, Sn, Pb, Sb, Bi and other harmful elements, and the Ca treatment can reduce the harm of the inclusion. P22 tube blank steel was produced by the process“EAF-LF-VD-CC”in Laiwu Steel, physical quality inspection shows that the steel is pure, the trace harmful elements are low, the temper brittleness sensitivity coefficient J and the CEF value were controlled ideal, the macrostructure and surface quality of the round billet are better.%依据钢的技术要求,设计了钢的化学成分及内控要求,采用纯净钢技术控制S、P及夹杂物,选用优质废钢和铁水控制As、Sn、Pb、Sb、Bi等有害元素,并通过Ca处理降低夹杂物的危害,莱钢采用EAF-LF-VD-CC工艺流程开发了P22管坯钢。实物质量检测表明,钢质纯净,微量有害元素低,回火脆性敏感系数J、CEF控制理想,圆坯低倍组织和表面质量良好。

  18. Feasibility of recovery boiler in paper and pulp industry

    International Nuclear Information System (INIS)

    in this paper feasibility of recovery boiler in terms of economics and environmental impacts in studied. Recovery boilers are employed in the pulp and paper industry where the cooking agent is recovered by burning black liquor. Cooking agent is exhausted due to the absorption of lignin (a burnable component) in cooking agent in the process of straw cooking. The process of recovery boiler is to remove lignin by combustion from black liquor, and heat is produced during the combustion of lignin which is used to produce steam. Recovery boiler is economical as it is recovering valuable chemicals and steam is produced as a byproduct. Steam from recovery boiler is also used for concentrating weak black liquor to concentrated black liquor recovering 50% of the utility water being used at the plant. The regenerated water in the form of foul condensate is reused in the process. The recovery of hazardous chemicals also reduces load of environmental pollution. Which otherwise can pollute the water reservoirs, and regeneration of water makes it environmentally friendly plant. Construction and challenges in operation of recovery boiler such as smelt-water explosion are also discussed in this paper. (author)

  19. Analysis of Causes for Corrosion of Tube Bundle Welded Joint of Waste Heat Boiler in Ammonia Synthesis System and Improvement%氨合成系统废热锅炉管束焊接接头腐蚀原因分析及改进

    Institute of Scientific and Technical Information of China (English)

    张英杰; 韩荣芹; 左卫锋

    2013-01-01

    氨合成系统废热锅炉投运8个月后,其管束的气体进口端联箱管与换热管间的焊接接头出现连续点状腐蚀坑样缺陷,而管束的气体出口端相应位置没有出现此类缺陷,设备其他部位未见异常.通过对氨合成系统废热锅炉管束焊接接头腐蚀部位的宏观形貌、低倍形态、化学组分、扩展方向及金相组织等特征进行分析,判定腐蚀形态为电偶腐蚀.针对腐蚀形态,采取了相应的改进措施,取得了明显的效果.%8 months after putting into operation of the waste heat boiler in ammonia synthesis system,defects of continuous dotted etch pit appeared at welded joints between gas inlet connecting tube and heat exchange tube of tube bundle,while no such kind of defect found at relevant position of gas outlet of tube bundle,and there are no troubles seen in other parts of the equipment.Through analyzing features of micro profile,macroscopic appearance,chemical composition,extension direction and metallographic structure,etc.of corroded parts of the tube bundle welded joints of the waste heat boiler in ammonia synthesis system,it is determined that the corrosion form is galvanic corrosion.In connection with the corrosion form,relevant improvement measures are taken and significant effect is obtained.

  20. COAL-FIRED UTILITY BOILERS: SOLVING ASH DEPOSITION PROBLEMS; TOPICAL

    International Nuclear Information System (INIS)

    The accumulation of slagging and fouling ash deposits in utility boilers has been a source of aggravation for coal-fired boiler operators for over a century. Many new developments in analytical, modeling, and combustion testing methods in the past 20 years have made it possible to identify root causes of ash deposition. A concise and comprehensive guidelines document has been assembled for solving ash deposition as related to coal-fired utility boilers. While this report accurately captures the current state of knowledge in ash deposition, note that substantial research and development is under way to more completely understand and mitigate slagging and fouling. Thus, while comprehensive, this document carries the title ''interim,'' with the idea that future work will provide additional insight. Primary target audiences include utility operators and engineers who face plant inefficiencies and significant operational and maintenance costs that are associated with ash deposition problems. Pulverized and cyclone-fired coal boilers are addressed specifically, although many of the diagnostics and solutions apply to other boiler types. Logic diagrams, ash deposit types, and boiler symptoms of ash deposition are used to aid the user in identifying an ash deposition problem, diagnosing and verifying root causes, determining remedial measures to alleviate or eliminate the problem, and then monitoring the situation to verify that the problem has been solved. In addition to a step-by-step method for identifying and remediating ash deposition problems, this guideline document (Appendix A) provides descriptions of analytical techniques for diagnostic testing and gives extensive fundamental and practical literature references and addresses of organizations that can provide help in alleviating ash deposition problems

  1. Life assessment for vintage boilers

    Energy Technology Data Exchange (ETDEWEB)

    Auerkari, P.; Salonen, J.; Holmstroem, S. (VTT Technical Research Centre of Finland, Espoo (Finland)); Laaksonen, L.; Lehtinen, O. (Fortum, Naantali (Finland)); McNiven, U. (Fortum, Jyvaeskylae (Finland)); Maekinen, S.; Vaeaenaenen, V. (Helsingin Energia, Helsinki (Finland)); Nikkarila, R. (Inspecta, Espoo (Finland))

    2010-05-15

    The high temperature sections of power and combined heat and power (CHP) boilers are designed for some de facto expected but finite life. Several significant damage mechanisms must be taken into account, particularly in superheaters and reheaters that are designed for creep but also suffer from thermal degradation, external erosion and corrosion, and internal steam oxidation that will gradually increase the metal temperature. As rising temperature tends to accelerate all damage mechanisms, major effects can be expected from the internal oxide growth. The feedback loop is taken into account in procedures to predict superheater life from known tube dimensions, time in operation, and other initial data. The oxide effect can be mitigated by internal cleaning, but in-service spallation of a relatively thick internal oxide can also become significant in old plants. Spallation can create problems but extends the tube life by keeping the wall cooler than with an adherent oxide. Examples are shown for boilers with more than 150 000 h of service. (orig.)

  2. Effect of Water Quality on the Performance of Boiler in Nigerian Petroleum Industry

    Directory of Open Access Journals (Sweden)

    J. O. ODIGURE

    2005-06-01

    Full Text Available This work investigates quality of water used in boilers of Refinery Company in Nigeria. The results shows that the quality of water fed to boilers are off specification. Low water quality used in boilers led to frequent failure of the boilers as a result of tube rupture. This has resulted into low capacity utilization and loss of processing fees. The poor performance of the boiler feed treatment plant is attributable to the deplorable condition of water intake plant, raw water treatment, demineralization plant, change in raw water quality and non-functioning of the polisher unit.

  3. The Modified Fouling Index Ultrafiltration constant flux for assessing particulate/colloidal fouling of RO systems

    NARCIS (Netherlands)

    Salinas-Rodriguez, S.G.; Amy, G.L.; Schippers, J.C.; Kennedy, M.D.

    2015-01-01

    Reliable methods for measuring and predicting the fouling potential of reverse osmosis (RO) feed water are important in preventing and diagnosing fouling at the design stage, and for monitoring pre-treatment performance during plant operation. The Modified Fouling Index Ultrafiltration (MFI-UF) cons

  4. Study of the Flow and Heat Transfer Characters in the Tube Sheet Cooling Chamber of a Fire Tube Waste Heat Boiler%火管式余热锅炉管板冷却室内流动传热研究

    Institute of Scientific and Technical Information of China (English)

    李超; 黄波; 代正华; 杨骥; 于广锁; 王辅臣

    2015-01-01

    气流床气化–废锅流程具有较高的热效率并可副产一定量蒸汽,适宜于整体气化联合循环(IGCC)发电或无需合成气变换的工况。文中对常用于气态/液体烃气流床气化的工业火锅式余热锅炉管板冷却室建立了三维数值模型。采用Realizable k-ε模型模拟了湍流流动过程,用离散坐标模型(DOM)计算了合成气辐射传热过程,耦合研究了流体与固体壁面间的流动和传热过程。考察了冷却水入口形式、冷却水流量和出口环隙宽度对冷却室内流动传热过程的影响。结果表明,3冷却水入口的形式能够有效改善合成气管水侧壁面的冷却效果,同时获得更均匀的冷却室内速度、温度分布。现有的2冷却水入口形式下,优化的冷却水质量流量为200 t/h。此外,在合成气管道的入口处加入刚玉套管能够使合成气管道壁面的最高温度降低106 K,有效保护合成气管端部。%Due to its high energy efficiency and steam production, the entrained-flow gasification process with the radiant and conductive cooler is suitable for the integrated gasification combined cycle (IGCC) or other processes without water gas shift unit. In this work, a 3D numerical model was established to study the characters of fluid dynamic and heat transfer of the tube sheet cooling chamber of a commercial scale fire-tube waste heat boiler, which was adopted in the gaseous/liquid hydrocarbon gasification process. The realizable k-ε model and discrete ordinate model (DOM) were employed to simulate the turbulence and syngas radiant heat transfer, respectively. The fluid-solid coupling analysis of flow and heat transfer was conducted. The effects of inlet types and mass flow of the cooling water and the width of the cooling water outlet on the velocity and temperature distribution were investigated. The results show that the 3 inlets of the cooling water is the most appropriate type in enhancing the

  5. Boiler conversions for biomass

    Energy Technology Data Exchange (ETDEWEB)

    Kinni, J. [Tampella Power Inc., Tampere (Finland)

    1996-12-31

    Boiler conversions from grate- and oil-fired boilers to bubbling fluidized bed combustion have been most common in pulp and paper industry. Water treatment sludge combustion, need for additional capacity and tightened emission limits have been the driving forces for the conversion. To accomplish a boiler conversion for biofuel, the lower part of the boiler is replaced with a fluidized bed bottom and new fuel, ash and air systems are added. The Imatran Voima Rauhalahti pulverized-peat-fired boiler was converted to bubbling fluidized bed firing in 1993. In the conversion the boiler capacity was increased by 10 % to 295 MWth and NO{sub x} emissions dropped. In the Kymmene Kuusankoski boiler, the reason for conversion was the combustion of high chlorine content biosludge. The emissions have been under general European limits. During the next years, the emission limits will tighten and the boilers will be designed for most complete combustion and compounds, which can be removed from flue gases, will be taken care of after the boiler. (orig.) 3 refs.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  7. Offshore fouling:investigation methods

    Institute of Scientific and Technical Information of China (English)

    YAN Tao; YAN Wenxia; DONG Yu; LIANG Guanhe; YAN Yan; WANG Huajie

    2004-01-01

    On the hasis of the reason that the offshore oil development areas in the northern South China Sea are at greater depth,more hazardous conditions and distance from shore, the methods and technologies used in coastal waters are not feasible because of the higher risk of losing investigation equipment or facilities. A series of methods and technologies for offshore fouling investigation that have been successfully applied is given in detail and it is hoped that the experience can be helpful for further studies.

  8. 超声波检测技术在锅炉受热面管氧化皮检测中的应用%Application of Ultrasonic Technique in Measuring Oxide-layer Thickness in Boiler Heat-absorbing Tube Inspection

    Institute of Scientific and Technical Information of China (English)

    张凤安; 朱邦同

    2014-01-01

    Measuring the thickness of oxide-layer in heat-absorbing tubes is always an important means to prevent heat-absorbing tubes from leaking.This paper mainly introduced the application of ultrasonic technique in measuring oxide-layer thickness in boiler finishing superheater of some power plant.By comparing the test results by microscope and endoscopy with the field data,it further validates the accuracy and reliability of this technology.At the same time,comparing this tech-nology with traditional RT technology and the measurement of oxide-layer in stainless steel tube bend was done and the measurement of oxide-layer by cutting tube was also done,and its advantages and prospect were pointed out.It has the cer-tain instruction function to guide the boiler inspection and guarantee the safe and economic operation of boilers.%锅炉受热面管氧化皮检测历来都是预防锅炉爆管的重要手段,主要介绍了超声波检测技术在某电厂锅炉末级过热器管内壁氧化皮检测中的实际应用,通过将超声波检测结果与内窥镜检查以及显微镜下的测量结果进行比较,进一步验证了该技术的准确性和可靠性。同时,将该技术与传统的射线拍片技术、不锈钢氧化皮堆积测量技术和割管取样测量等方法做了比较,指出超声波检测技术的优势及应用前景,对指导锅炉检修及保障锅炉安全经济运行具有一定的指导作用。

  9. Tube Wall Temperature Calculation and Oxide Film Effects Analysis on High-temperature Confection Heating Surface of Utility Boiler%电站锅炉高温对流受热面壁温计算及氧化膜影响分析

    Institute of Scientific and Technical Information of China (English)

    吴恺; 王甲安; 吕伟为; 徐鸿

    2015-01-01

    火电厂锅炉爆管事故是电厂事故中最常见的情形之一,爆管事故的发生对电厂的安全性经济性影响巨大。而此类问题的发生和锅炉管壁温度超温密不可分,因此若能全面准确可靠的监测受热面管壁温度将对电厂意义重大。但是电厂锅炉由于炉内壁温测点安装较困难,另外由于炉内温度高,即使安装了测点,测点通常寿命不长。通常安装在炉外大包内的壁温测点只能在一定程度上反应管道内部介质的温度,而对于最危险处的壁温却无法直接得到。本文针对此问题,对壁温计算模型进行了分析,利用Fluent数值模拟软件进行了燃烧模拟计算,使用Delphi语言对该计算模型编制了相应的程序,结合某电厂2028t/h锅炉实例进行计算,并假设氧化膜存在对结果的影响进行了再次计算和分析。能对电厂锅炉的安全运行提供正确的指导,也可为电厂锅炉管道的及时检修提出指导,具有重要的工程实用价值。%Power plant boiler pipe rupture accident is one of the most common situations in power plant. Tube-burst accident has had a huge impact on the safety and economy in Power plant. The occurrence of such problems are inextricably linked with the boiler tube wall over-temperature, so it is great significance to comprehensively accurately and reliably mon-itor the tube wall temperature of heat exchangers in power plants. But due to the power plant boiler furnace wall temperature measuring point is difficult to install. Even if installed, the high temperature in the furnace usually makes it not long life. For the most dangerous place, the wall temperature cannot directly obtain.Aimed at this problem, this author analyze the wall temperature calculation model, combined with power plant example of 2028 t/h boiler, use Delphi language to compile the corresponding program for the calculation model, use numerical simulation software Fluent to

  10. Solved and unsolved problems in boiler systems. Learning from accidents

    International Nuclear Information System (INIS)

    This paper begins with a brief review on the similarity law of conventional fossil-fuel-fired boilers. The concept is based on the fact that the heat release due to combustion in the furnace is restricted by the furnace volume but the heat absorption is restricted by the heat transfer surface area. This means that a small-capacity boiler has relatively high specific furnace heat release rate, about 10 MW/m3, and on the contrary a large-capacity boiler has lower value. The surface-heat-flux limit is mainly dominated by the CHF inside the water-wall tubes of the boiler furnace, about 350 kW/m2. This heat-flux limit is almost the same order independently on the capacity of boilers. For the safety of water-walls, it is essential to retain suitable water circulation, i.e. circulation ratio and velocity of water. This principle is a common knowledge of boiler designer, but actual situation is not the case. Newly designed boilers often suffer from similar accidents, especially burnout due to circulation problems. This paper demonstrates recent accidents encountered in practical boilers, and raises problems of rather classical but important two-phase flow and heat transfer. (author)

  11. Reliability Based Management of Marine Fouling

    DEFF Research Database (Denmark)

    Faber, Michael Havbro; Hansen, Peter Friis

    1999-01-01

    obtained by the present model taking into account seasonal effects with those inherent in the current design specifications are made and criteria are formulated for removal of marine fouling taking into account seasonal differences in marine fouling. A methodology is outlined on how to establish new......The present paper describes the results of a recent study on the application of methods from structural reliability to optimise management of marine fouling on jacket type structures.In particular the study addresses effects on the structural response by assessment and quantification...... of uncertainties of a set of parameters. These are the seasonal variation of marine fouling parameters, the wave loading (taking into account the seasonal variation in sea-state statistics), and the effects of spatial variations and seasonal effects of marine fouling parameters. Comparison of design values...

  12. Modelling transition states of a small once-through boiler

    Energy Technology Data Exchange (ETDEWEB)

    Talonpoika, T. [Lappeenranta Univ. of Technology (Finland). Dept. of Energy Technology

    1997-12-31

    This article presents a model for the unsteady dynamic behaviour of a once-through counter flow boiler that uses an organic working fluid. The boiler is a compact waste-heat boiler without a furnace and it has a preheater, a vaporiser and a superheater. The relative lengths of the boiler parts vary with the operating conditions since they are all parts of a single tube. The boiler model is presented using a selected example case that uses toluene as the process fluid and flue gas from natural gas combustion as the heat source. The dynamic behaviour of the boiler means transition from the steady initial state towards another steady state that corresponds to the changed process conditions. The solution method chosen is to find such a pressure of the process fluid that the mass of the process fluid in the boiler equals the mass calculated using the mass flows into and out of the boiler during a time step, using the finite difference method. A special method of fast calculation of the thermal properties is used, because most of the calculation time is spent in calculating the fluid properties. The boiler is divided into elements. The values of the thermodynamic properties and mass flows are calculated in the nodes that connect the elements. Dynamic behaviour is limited to the process fluid and tube wall, and the heat source is regarded as to be steady. The elements that connect the preheater to the vaporiser and the vaporiser to the superheater are treated in a special way that takes into account a flexible change from one part to the other. The initial state of the boiler is received from a steady process model that is not a part of the boiler model. The known boundary values that may vary during the dynamic calculation were the inlet temperature and mass flow rates of both the heat source fluid and the process fluid. The dynamic boiler model is analysed for linear and step charges of the entering fluid temperatures and flow rates. The heat source side tests show that

  13. Numerical simulation of the fouling process

    Energy Technology Data Exchange (ETDEWEB)

    Brahim, Fahmi; Augustin, Wolfgang; Bohnet, Matthias [Institut fuer Chemische und Termische Verfahrenstechnik, Technische Universitaet Braunschweig, Langer Kamp 7, 38106, Braunschweig (Germany)

    2003-03-01

    Fouling of heat transfer surfaces causes serious technical and economic problems in industry. The goal of this work is to simulate the aforementioned fouling process using the CFD code FLUENT. The obtained numerical results assist in designing and running heat exchangers.Based on models for the calculation of deposition and removal mass rates [S. Krause, Internat. Chem. Engrg. 33 (1993)], the crystallization fouling of calcium sulfate on flat heat transfer surfaces was simulated. The induction period, which occurs with almost all fouling processes, was therefore not considered.The simulation of real crystal growth requires a continuous variation of the geometric flow model and therefore considerable computational effort. For that reason fictitious crystal growth was simulated instead. This numerical simplification enabled an unsteady simulation to be obtained, of the fouling process and a realistic description of the temporal modification of both the flow and temperature field due to the continuous crystal growth.Based on experimental results of Hirsch [M. Bohnet et al., in: T.R. Bott et al. (Eds.), Understanding Heat Exchanger Fouling and its Mitigation, United Engineering Foundation and Begell House, New York, 1997, pp. 201-208], a model was developed which enables the calculation of the density of the fouling layer not only as a function of the local position within the fouling layer, but also as a function of the time-dependent total thickness of the fouling layer. In addition a model was developed, that enables a realistic distribution of the heat flux along the heat transfer surface during the simulation. Both models provide a more exact description of the complicated fouling process.Results of the numerical simulation are the prediction of the fouling resistance as a function of time and the calculation of the temperature distribution within the fouling layer. In view of the complexity of the fouling process during the incrustation of heat transfer surfaces

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

    Science.gov (United States)

    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…

  15. Drying Milk With Boiler Exhaust

    Science.gov (United States)

    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.

  16. Investigation of a twisted-tube type shell-and-tube heat exchanger

    OpenAIRE

    Danielsen, Sven Olaf

    2009-01-01

    This master thesis investigates twisted tube type shell-and-tube heat exchangers with emphasis on thermal-hydraulic characteristics, fouling and vibration properties. An extensive literature study has been carried out in order to map all published research reports written on the topic. The mapping of performed research shows that the available information is limited.Mathematical correlations for twisted tube thermal-hydraulic characteristics are extracted from the research reports found in th...

  17. Fouling distribution in forward osmosis membrane process.

    Science.gov (United States)

    Lee, Junseok; Kim, Bongchul; Hong, Seungkwan

    2014-06-01

    Fouling behavior along the length of membrane module was systematically investigated by performing simple modeling and lab-scale experiments of forward osmosis (FO) membrane process. The flux distribution model developed in this study showed a good agreement with experimental results, validating the robustness of the model. This model demonstrated, as expected, that the permeate flux decreased along the membrane channel due to decreasing osmotic pressure differential across the FO membrane. A series of fouling experiments were conducted under the draw and feed solutions at various recoveries simulated by the model. The simulated fouling experiments revealed that higher organic (alginate) fouling and thus more flux decline were observed at the last section of a membrane channel, as foulants in feed solution became more concentrated. Furthermore, the water flux in FO process declined more severely as the recovery increased due to more foulants transported to membrane surface with elevated solute concentrations at higher recovery, which created favorable solution environments for organic adsorption. The fouling reversibility also decreased at the last section of the membrane channel, suggesting that fouling distribution on FO membrane along the module should be carefully examined to improve overall cleaning efficiency. Lastly, it was found that such fouling distribution observed with co-current flow operation became less pronounced in counter-current flow operation of FO membrane process.

  18. Mitigating the Risk of Stress Corrosion of Austenitic Stainless Steels in Advanced Gas Cooled Reactor Boilers

    International Nuclear Information System (INIS)

    Advanced Gas-Cooled Reactors (AGRs) operated in the UK by EDF Energy have once-through boilers, which deliver superheated steam at high temperature (∼500 deg. C) and pressure (∼150 bar) to the HP turbine. The boilers have either a serpentine or helical geometry for the tubing of the main heat transfer sections of the boiler and each individual tube is fabricated from mild steel, 9%Cr1%Mo and Type 316 austenitic stainless steel tubing. Type 316 austenitic stainless steel is used for the secondary (final) superheater and steam tailpipe sections of the boiler, which, during normal operation, should operate under dry, superheated steam conditions. This is achieved by maintaining a specified margin of superheat at the upper transition joint (UTJ) between the 9%Cr1%Mo primary superheater and the Type 316 secondary superheater sections of the boiler. Operating in this mode should eliminate the possibility of stress corrosion cracking of the Type 316 tube material on-load. In recent years, however, AGRs have suffered a variety of operational problems with their boilers that have made it difficult to maintain the specified superheat margin at the UTJ. In the case of helical boilers, the combined effects of carbon deposition on the gas side and oxide deposition on the waterside of the tubing have resulted in an increasing number of austenitic tubes operating with less than the specified superheat margin at the UTJ and hence the possibility of wetting the austenitic section of the boiler. Some units with serpentine boilers have suffered creep-fatigue damage of the high temperature sections of the boiler, which currently necessitates capping the steam outlet temperature to prevent further damage. The reduction in steam outlet temperature has meant that there is an increased risk of operation with less than the specified superheat margin at the UTJ and hence stress corrosion cracking of the austenitic sections of the boiler. In order to establish the risk of stress

  19. Oil shale fueled FBC power plant - ash deposits and fouling problems

    Energy Technology Data Exchange (ETDEWEB)

    O. Yoffe; A. Wohlfarth; Y. Nathan; S. Cohen; T. Minster [Geological Survey of Israel, Jerusalem (Israel)

    2007-12-15

    41 MWth oil shale fired demonstration power plant was built in 1989 by PAMA in Mishor Rotem, Negev, Israel. The raw material for the plant is the local 'oil shale', which is in fact organic-rich marl. Since then, and until today, the unit is operated at high reliability and availability. At first, heavy soft fouling occurred due to the Circulating Fluidized Bed Combustion (CFBC) mode of operation, which caused a considerable reduction in the heat transfer coefficient of the heat exchangers. By going over to the Fluidized Bed Combustion (FBC) mode of operation the soft fouling phenomenon stopped at once, the heat transfer coefficient improved, and the power plant could be operated at its designed values. After five months of operation at the FBC mode the boiler had to be shut down because Hard Deposits (HD) blocked physically the passes in the boiler. These deposits could be removed only with the help of mechanical devices. During the first two years the boiler had to be stopped, at least, three times a year for deposit cleaning purposes. Research conducted at the plant and in the laboratories of the Geological Survey of Israel enabled us to understand the mechanism of formation of these deposits. The results showed that the HD are formed in two stages: (1) Deposition of very fine ash particles on the pipes of the boiler, as a result of the impact of larger particles on the pipes. The fine particles adhere to the pipes and to each other, and step by step build the deposit. The growth of the deposit on the pipe surface is always perpendicular to the particles flow direction. (2) The deposits harden due to chemical reactions. 17 refs., 14 figs., 5 tabs.

  20. Oxy-Combustion Boiler Material Development

    Energy Technology Data Exchange (ETDEWEB)

    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

  1. Oxy-Combustion Boiler Material Development

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Keiser, J.R.; Hubbard, C.R.; Payzant, E.A. [Oak Ridge National Lab., TN (United States)] [and others

    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.

  3. Cause Analysis and Preventive Measures on Bursting of High Temperature Superheater Tubes of 680 t/h Power Station Boiler%680t/h电站锅炉高温过热器爆管原因分析及预防措施

    Institute of Scientific and Technical Information of China (English)

    王小聪; 黎华; 马括; 卢忠铭

    2012-01-01

    Bursting of high temperature superheater tubes of 680 t/h power station boiler coccured twice reeently, and macroscopic examination, chemical compositions analysis and metallographic examination were investigated to find the casuse, the results showed that the failure was due to overheat which led to primary creep, then some effective prevention measures were taken.%某台680t/h电站锅炉高温过热器最近发生两起爆管事故,通过对爆管样管进行宏观检验、化学成分分析和金相检验判断爆管的根本原因。结果表明:由于长时间超温运行导致管子早期蠕变引起爆管,并采取了有效的预防措施。

  4. Application of the decree 2910 for coal fired boilers; Application de l`arrete 2910 aux chaudieres a charbon

    Energy Technology Data Exchange (ETDEWEB)

    Hing, K. [CDF Energie, Charbonnages de France, 92 - Rueil-Malmaison (France)

    1997-12-31

    The impacts of the new French decree 2910 concerning the classification of all combustion equipment with regards to their energy sources, energy efficiency and pollution control, on 2 to 20 MW coal-fired boilers, are discussed, with emphasis on their pollutant emissions (SO{sub 2}, NO{sub x} and ashes). The compositions of several coals is presented and the various types of coal-fired boilers adapted to the new decree are presented: automatic boilers, dense fluidized bed boilers, vibrating and chain grids with fume tubes and water tubes

  5. ENERGY STAR Certified Boilers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 3.0 ENERGY STAR Program Requirements for Boilers that are effective as of October 1,...

  6. Fouling and Antifouling of Depetanizer in Ethylene Units

    Institute of Scientific and Technical Information of China (English)

    Dong Zhongjie; Li Yunlong; Fan Xuezhi; Hong Qingyao

    2002-01-01

    Factors affecting fouling of depentanizer in ethylene units wereexplored through study of thecomposition of pyrolysis gasoline, C5 distillate and fouling deposits from the depentanizer while takinginto consideration the processing parameters. A variety of antifouling measures, in particular the injec-tion of a special anti-fouling agent into the Cs gas phase pipeline and the C5 distillate reflux pipelinewere introduced. Commercial evaluation test of a multifunctional anti-fouling agent, the RIPP-1404anti-fouling agent, was also described.

  7. A Flue Gas Tube for Thermoelectric Generator

    DEFF Research Database (Denmark)

    2013-01-01

    The invention relates to a flue gas tube (FGT) (1) for generation of thermoelectric power having thermoelectric elements (8) that are integrated in the tube. The FTG may be used in combined heat and power (CHP) system (13) to produce directly electricity from waste heat from, e.g. a biomass boiler...

  8. Steam boiler technology

    Energy Technology Data Exchange (ETDEWEB)

    Teir, S.

    2003-07-01

    This book is the published version of the e-book with the same name. The interactive lecture slides, which accompany most chapters, exist only in the online version and on the attached CD-Rom. The Steam Boiler Technology e-book is the main course book for the course on steam boiler technology provided by the Laboratory of Energy Engineering and Environmental Protection at Helsinki University of Technology. The steam boiler technology e-Book is provided by the Laboratory of Energy Engineering and Environmental Protection at Helsinki University of Technology. The book covers the basics and the history of steam generation, modern boilers types and applications, steam/water circulation design, feedwater and steam systems components, heat exchangers in steam boilers, boiler calculations, thermal design of heat exchangers. The chapters of the second edition have been corrected based on reader and reviewer comments, and four new chapters have been added. The user interface of the electronic version has also been updated. The password for the online book will be changed once a year. If you have problems accessing the online book, or need a new password, please contact sebastian.teir@hut.fi.

  9. Ash particle erosion on steam boiler convective section

    Energy Technology Data Exchange (ETDEWEB)

    Meuronen, V.

    1997-12-31

    In this study, equations for the calculation of erosion wear caused by ash particles on convective heat exchanger tubes of steam boilers are presented. A new, three-dimensional test arrangement was used in the testing of the erosion wear of convective heat exchanger tubes of steam boilers. When using the sleeve-method, three different tube materials and three tube constructions could be tested. New results were obtained from the analyses. The main mechanisms of erosion wear phenomena and erosion wear as a function of collision conditions and material properties have been studied. Properties of fossil fuels have also been presented. When burning solid fuels, such as pulverized coal and peat in steam boilers, most of the ash is entrained by the flue gas in the furnace. In bubbling and circulating fluidized bed boilers, particle concentration in the flue gas is high because of bed material entrained in the flue gas. Hard particles, such as sharp edged quartz crystals, cause erosion wear when colliding on convective heat exchanger tubes and on the rear wall of the steam boiler. The most important ways to reduce erosion wear in steam boilers is to keep the velocity of the flue gas moderate and prevent channelling of the ash flow in a certain part of the cross section of the flue gas channel, especially near the back wall. One can do this by constructing the boiler with the following components. Screen plates can be used to make the velocity and ash flow distributions more even at the cross-section of the channel. Shield plates and plate type constructions in superheaters can also be used. Erosion testing was conducted with three types of tube constructions: a one tube row, an in- line tube bank with six tube rows, and a staggered tube bark with six tube rows. Three flow velocities and two particle concentrations were used in the tests, which were carried out at room temperature. Three particle materials were used: quartz, coal ash and peat ash particles. Mass loss

  10. Heat flux distribution on circulating fluidized bed boiler water wall

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The future of circulating fluidized bed (CFB)combustion technology is in raising the steam parameters to supercritical levels.Understanding the heat flux distribution on the water wall is one of the most important issues in the design and operation of supercritical pressure CFB boilers.In the present paper,the finite element analysis (FEA) method is adopted to predict the heat transfer coefficient as well as the heat flux of the membrane wall and the results are validated by direct measurement of the temperature around the tube.Studies on the horizontal heat flux distribution were conducted in three CFB boilers with different furnace size,tube dimension and water temperature.The results are useful in supercritical pressure CFB boiler design.

  11. Thermal-hydraulic analysis of a 600 MW supercritical CFB boiler with low mass flux

    International Nuclear Information System (INIS)

    Supercritical Circulating Fluidized Bed (CFB) boiler becomes an important development trend for coal-fired power plant and thermal-hydraulic analysis is a key factor for the design and operation of water wall. According to the boiler structure and furnace-sided heat flux, the water wall system of a 600 MW supercritical CFB boiler is treated in this paper as a flow network consisting of series-parallel loops, pressure grids and connecting tubes. A mathematical model for predicting the thermal-hydraulic characteristics in boiler heating surface is based on the mass, momentum and energy conservation equations of these components, which introduces numerous empirical correlations available for heat transfer and hydraulic resistance calculation. Mass flux distribution and pressure drop data in the water wall at 30%, 75% and 100% of the boiler maximum continuous rating (BMCR) are obtained by iteratively solving the model. Simultaneity, outlet vapor temperatures and metal temperatures in water wall tubes are estimated. The results show good heat transfer performance and low flow resistance, which implies that the water wall design of supercritical CFB boiler is applicable. - Highlights: → We proposed a model for thermal-hydraulic analysis of boiler heating surface. → The model is applied in a 600 MW supercritical CFB boiler. → We explore the pressure drop, mass flux and temperature distribution in water wall. → The operating safety of boiler is estimated. → The results show good heat transfer performance and low flow resistance.

  12. PERFORMANCE EVALUATION OF BOILERS (80 AND 40 TPH AND 21MW STEAM TURBINE OF COGEN PLANT

    Directory of Open Access Journals (Sweden)

    D.P.TAWARE

    2014-06-01

    Full Text Available The proposed study is conducted at The Malegaon Sugar Mills, Baramati, and District Pune. Data is collected for a high pressure 80 TPH & 40TPH bagasse fired boiler. The boilers are natural circulation and bi-drum water tube type. The both boilers are equipped with super heater, air heater and economizer in order to utilize maximum available heat of flue gases. Boiler efficiency is calculated by indirect method. Also plant has 21 MW cogeneration capacity, with two turbines are installed with capacity 14MW (Back Pressure Type & 7MW (Extraction Cum Condensing Type. From the heat input given to turbines per unit of electricity generated, the turbine heat rate is calculated. Different instruments and devices are used to record the different parameters of both boilers & turbines. Steam produced per ton of bagasse is being found out for both boilers.

  13. 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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xingbo [West Virginia Univ., Morgantown, WV (United States)

    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.

  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

    Energy Technology Data Exchange (ETDEWEB)

    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. The causes for the leakage of DZL type boiler smoke tube bulge mouth and maintenance%DZL型锅炉烟管胀口泄漏的原因及维修

    Institute of Scientific and Technical Information of China (English)

    李杰; 郭建新; 王儒瑞

    2014-01-01

    本文主要探讨在高温烟气中,锅炉的某些高温原件将与烟气中的氧发生氧化反应,生成氧化膜,如果氧化膜不能紧密地包覆在钢材表面而发生脱落,则氧化现象将不断发展,导致的破坏。对修理预防,防止蒸汽锅炉事故有着一定的现实意义。%This article mainly discusses in high temperature flue gas,original some of boiler high temperature oxidizing reaction with the oxygen in flue gas,generated oxide film,if oxidation film can't closely coated on the surface of steel and fall off,the oxidation phenomenon will continuously development,lead to destruction.For repair prevention, prevent accident of steam boiler has a certain practical significance..

  16. Drag of Clean and Fouled Net Panels--Measurements and Parameterization of Fouling.

    Directory of Open Access Journals (Sweden)

    Lars Christian Gansel

    Full Text Available Biofouling is a serious problem in marine aquaculture and it has a number of negative impacts including increased forces on aquaculture structures and reduced water exchange across nets. This in turn affects the behavior of fish cages in waves and currents and has an impact on the water volume and quality inside net pens. Even though these negative effects are acknowledged by the research community and governmental institutions, there is limited knowledge about fouling related effects on the flow past nets, and more detailed investigations distinguishing between different fouling types have been called for. This study evaluates the effect of hydroids, an important fouling organism in Norwegian aquaculture, on the forces acting on net panels. Drag forces on clean and fouled nets were measured in a flume tank, and net solidity including effect of fouling were determined using image analysis. The relationship between net solidity and drag was assessed, and it was found that a solidity increase due to hydroids caused less additional drag than a similar increase caused by change in clean net parameters. For solidities tested in this study, the difference in drag force increase could be as high as 43% between fouled and clean nets with same solidity. The relationship between solidity and drag force is well described by exponential functions for clean as well as for fouled nets. A method is proposed to parameterize the effect of fouling in terms of an increase in net solidity. This allows existing numerical methods developed for clean nets to be used to model the effects of biofouling on nets. Measurements with other types of fouling can be added to build a database on effects of the accumulation of different fouling organisms on aquaculture nets.

  17. Investigation and Treatment of Defects in T23 Steel Welding Joint for water-wall tubes in Ultra-supercritical Tower-type Boiler%超超临界机组塔式炉T23水冷壁缺陷成因分析及治理研究

    Institute of Scientific and Technical Information of China (English)

    宫广正

    2014-01-01

    T23管焊接接头失效已成为超超临界机组安全运行的重大隐患。以某电厂百万超超临界塔式锅炉为例,对锅炉水冷壁T23管开裂原因进行分析,发现焊接接头韧性不足和残余应力水平较高是导致失效的主要因素,据此提出了T23钢管焊接接头缺陷的治理措施。%The failure of T23 Steel tube welded joints has become an important hidden danger to safety operation of ultra-su-percritical units. This paper investigated the cracking reasons of T23 Steel water-wall tube in a 1,000 MW ultra-supercritical tower-type boiler and found the major causes are lacking of the toughness and high level of the residual stress in welding joints. According to the result, a treatment measure of the T23 Steel welded joints was suggested.

  18. 46 CFR 59.10-20 - Patches in shells and tube sheets.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Patches in shells and tube sheets. 59.10-20 Section 59... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Boilers and Pressure Vessels in -Service § 59.10-20 Patches in shells and tube sheets. (a) Unreinforced openings in the shells or drums...

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

    Energy Technology Data Exchange (ETDEWEB)

    Gandy, David W. [Electric Power Research Institute, Inc., Palo Alto, CA (United States); Shingledecker, John P. [Electric Power Research Institute, Inc., Palo Alto, CA (United States)

    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.

  20. Control Properties of Bottom Fired Marine Boilers

    DEFF Research Database (Denmark)

    Solberg, Brian; Andersen, Palle; Karstensen, Claus M. S.

    2007-01-01

    This paper focuses on model analysis of a dynamic model of a bottom fired one-pass smoke tube boiler. Linearized versions of the model are analyzed and show large variations in system gains at steady state as function of load whereas gain variations near the desired bandwidth are small. An analysis...... showed substantial improvement compared to a decentralized scheme based on sequential loop closing. Similar or better result is expected to be obtainable using a full Multiple input Multiple output scheme. Furthermore closed loop simulations, applying a linear controller to the nonlinear plant model...... on states and control signals should be considered....

  1. On the design of residential condensing gas boilers

    Energy Technology Data Exchange (ETDEWEB)

    Naeslund, M.

    1997-02-01

    Two main topics are dealt with in this thesis. Firstly, the performance of condensing boilers with finned tube heat exchangers and premix burners is evaluated. Secondly, ways of avoiding condensate formation in the flue system are evaluated. In the first investigation, a transient heat transfer approach is used to predict performance of different boiler configurations connected to different heating systems. The smallest efficiency difference between heat loads and heating systems is obtained when the heat exchanger gives a small temperature difference between flue gases and return water, the heat transfer coefficient is low and the thermostat hysteresis is large. Taking into account heat exchanger size, the best boiler is one with higher heat transfer per unit area which only causes a small efficiency loss. The total heating cost at part load, including gas and electricity, has a maximum at the lowest simulated heat load. The heat supplied by the circulation heat pump is responsible for this. The second investigation evaluates methods of drying the flue gases. Reheating the flue gases in different ways and water removal in an adsorbent bed are evaluated. Reheating is tested in two specially designed boilers. The necessary reheating is calculated to approximately 100-150 deg C if an uninsulated masonry chimney is used. The tested boilers show that it is possible to design a proper boiler. The losses, stand-by and convective/radiative, must be kept at a minimum in order to obtain a high efficiency. 86 refs, 70 figs, 16 tabs

  2. Geometrical Optimization for Outlet Tubes at Header of Top Roof Superheater in a Utility Boiler of a Power Plant%某电厂汽包锅炉过热器顶棚管联箱结构优化研究

    Institute of Scientific and Technical Information of China (English)

    吕玉贤; 庞力平; 李文学

    2014-01-01

    针对某电厂锅炉顶棚过热器频繁爆管现象,建立了与现场实际相同的几何模型,采用计算流体动力学方法对联箱内部流动情况进行数值研究。研究发现联箱三通附近由于静压分布异常,导致引入管周边的分支管静压较低,流量分配相对减少,发生传热恶化,进而发生爆管。该文提出优化的几何结构,通过对特定分支管引出方向进行调整,显著提升了并联分支管流量分配的均匀性,为电站锅炉分配联箱设计和结构优化提供一定的参考。%Numerical simulation was performed on the internal flow of header using the method of computational fluid dynamics with geometry model builded the same as practical field for the frequent rupture of roof superheater in a power station. The results indicate that due to the abnormal static pressure distribution in the area of Tee-junction of header, the static pressure of the branch pipes around inlet tube is so low, and the mass flow rate decreases relatively, then the heat transferation of tubes deteriorates,finally the tubes rupture. This paper proposes an improved geometric construction. By changing the leading direction of specific branch pipes, the uniformity of mass flow distribution in branch pipes promotes significient. It will offer a great reference for further design and optimization of distribution header in power station boilers.

  3. Investigation of organic fouling of microfiltration membrane

    Institute of Scientific and Technical Information of China (English)

    XIAO Feng; CUI Chong-wei; MA Jun

    2005-01-01

    Because the natural organic matters (NOMs) and proteins are the principal foulants of microfiltration membranes in drinking water, the primary aim of this paper is to obtain a better understanding of the interactions between those foulants and the microfiltration membrane from a novel view of coagulation. Based on reviewed literature and our own analysis, the authors consider that the behaviors of NOMs in the fouling of microfiltration membrane are like a form of crystal growth, and we recognize that the extent of the membrane hydrophobicity plays an essential role in NOMs fouling. However, proteins' fouling is more affected by intermolecular interaction. Additionally, the effect of membrane surface chemistry is not as essential as it is in the situation of NOMs.

  4. MODELLING, SIMULATING AND OPTIMIZING BOILERS

    DEFF Research Database (Denmark)

    Sørensen, Kim; Condra, Thomas Joseph; Houbak, Niels

    2004-01-01

    of the boiler is (with an acceptable accuracy) proportional with the volume of the boiler. For the dynamic operation capability a cost function penalizing limited dynamic operation capability and vise-versa has been dened. The main idea is that it by mean of the parameters in this function is possible to t its...... shape to the actual application. In the paper an optimization example is shown and the results discussed. By means of the developed model it is shown how the optimum changes from a boiler favoring a good dynamic capability (i.e. a boiler with a relatively large volume) to a boiler not penalizing...

  5. The economics of repeated tube thickness surveys

    International Nuclear Information System (INIS)

    The use of tube thickness surveys in boilers is an example of a commonly applied condition monitoring (CM) technique for maintenance and it leads to condition-based maintenance (CBM) of the boiler tubes. There are, however, limits to the economics of this type of strategy which are frequently overlooked in discussion of CBM strategies. This paper considers several models of maintenance strategies. Conditions in which breakdown maintenance (BM), routine total replacement (routine maintenance, RM) and condition-based replacement (which for simplicity is referred to as CM) are considered. Some general rules about the economical range of each strategy are developed. The case study examines the use of ultrasonic testing of boiler tubes in power stations in some detail

  6. 76 FR 33204 - Certain Welded Carbon Steel Pipe and Tube From Turkey; Notice of Preliminary Results of...

    Science.gov (United States)

    2011-06-08

    ... Order; Welded Carbon Steel Standard Pipe and Tube Products From Turkey, 51 FR 17784 (May 15, 1986... goods, boiler tubing, cold- drawn or cold-rolled mechanical tubing, pipe and tube hollows for redraws... Carbon Steel Pipe and Tube from Turkey, 71 FR 26043 (May 3, 2006), unchanged in Notice of Final...

  7. Hydrodynamic approaches to reducing membrane fouling

    Energy Technology Data Exchange (ETDEWEB)

    Davis, R.H. [Univ. of Colorado, Boulder, CO (United States)

    1995-12-01

    Membranes are gaining increasing use in a wide variety of liquid and gas separations. A pervasive problem is membrane fouling due to material depositing on the membrane surface and within the membrane pore structure. Professor Georges Belfort has made significant contributions to reducing membrane fouling by hydrodynamic approaches for ultrafiltration and microfiltration. I will review some of his work, as well as related work by myself and others, in this area. Topics which will be discussed include particle migration during crossflow filtration, curved channels which promote centrifugal instabilities, and rapid backpulsing.

  8. Installations of SNCR on bark-fired boilers

    International Nuclear Information System (INIS)

    Experience has been collected from the twelve bark-fired boilers in Sweden with selective non catalytic reduction (SNCR) installations to reduce emissions of nitrogen oxides. Most of the boilers have slope grates, but there are also two boilers with cyclone ovens and two fluidized bed boilers. In addition to oil there are also possibilities to burn other fuel types in most boilers, such as sludge from different parts of the pulp and paper mills, saw dust and wood chips. The SNCR installations seems in general to be of simple design. In most installations the injection nozzles are located in existing holes in the boiler walls. The availability is reported to be good from several of the SNCR installations. There has been tube leakage in several boilers. The urea system has resulted in corrosion and in clogging of one oil burner. This incident has resulted in a decision not to use SNCR system with the present design of the system. The fuel has also caused operational problems with the SNCR system in several of the installations due to variations in the moisture content and often high moisture content in bark and sludge, causing temperature variations. The availability is presented to be high for the SNCR system at several of the plants, in two of them about 90 %. The results in NOx reduction vary between the installations depending on boiler, fuel and operation. The emissions are between 45 and 100 mg NO2/MJ fuel input and the NOx reduction rates are in most installations between 30 and 40 %, the lowest 20 and the highest 70 %. 13 figs, 3 tabs

  9. Two-phase flow for fouling control in membranes

    NARCIS (Netherlands)

    Wibisono, Yusuf

    2014-01-01

    The real challenge of the use of NF/RO spiral-wound membrane modules in water treatment is membrane fouling. Fouling problems in NF/RO systems are more complicated than in low pressure membrane processes, becaused fouling usually occurs on the nanoscale, combined with the complex geometry of spiral-

  10. 49 CFR 236.104 - Shunt fouling circuit.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunt fouling circuit. 236.104 Section 236.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Inspections and Tests; All Systems § 236.104 Shunt fouling circuit. Shunt fouling...

  11. NOx Control Options and Integration for US Coal Fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Mike Bockelie; Kevin Davis; Temi Linjewile; Connie Senior; Eric Eddings; Kevin Whitty; Larry Baxter; Calvin Bartholomew; William Hecker; Stan Harding

    2004-03-31

    This is the fifteenth Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. At AEP's Gavin Plant, data from the corrosion probes showed that corrosion rate increased as boiler load was increased. During an outage at the plant, the drop in boiler load, sensor temperature and corrosion rate could all be seen clearly. Restarting the boiler saw a resumption of corrosion activity. This behavior is consistent with previous observations made at a 600MWe utility boiler. More data are currently being examined for magnitudes of corrosion rates and changes in boiler operating conditions. Considerable progress was made this quarter in BYU's laboratory study of catalyst deactivation. Surface sulfation appears to partially suppress NO adsorption when the catalyst is not exposed to NH3; NH3 displaces surface-adsorbed NO on SCR catalysts and surface sulfation increases the amount of adsorbed NH3, as confirmed by both spectroscopy and TPD experiments. However, there is no indication of changes in catalyst activity despite changes in the amount of adsorbed NH3. A monolith test reactor (MTR), completed this quarter, provided the first comparative data for one of the fresh and field-exposed monolith SCR catalysts yet developed in this project. Measurements of activity on one of the field-exposed commercial monolith catalysts do not show significant changes in catalyst activity (within experimental error) as compared to the fresh catalyst. The exposed surface of the sample contains large amounts of Ca and Na, neither of which is present in the fresh sample, even after removal of visibly obvious fouling deposits. However, these fouling compounds do

  12. Optimization of Load Assignment to Boilers in Industrial Boiler Plants

    Institute of Scientific and Technical Information of China (English)

    CAO Jia-cong; QIU Guang; CAO Shuang-hua; LIU Feng-qiang

    2004-01-01

    Along with the increasing importance of sustainable energy, the optimization of load assignment to boilers in an industrial boiler plant becomes one of the major projects for the optimal operation of boiler plants. Optimal load assignment for power systems has been a long-lasting subject, while it is quite new for industrial boiler plants. The existing methods of optimal load assignment for boiler plants are explained and analyzed briefly in the paper. They all need the fuel cost curves of boilers. Thanks to some special features of the curves for industrial boilers, a new model referred to as minimized departure model (MDM) of optimization of load assignment for boiler plants is developed and proposed in the paper. It merely relies upon the accessible data of two typical working conditions to build the model, viz. the working conditions with the highest efficiency of a boiler and with no-load. Explanation of the algorithm of computer program is given, and effort is made so as to determine in advance how many and which boilers are going to work. Comparison between the results using MDM and the results reported in references is carried out, which proves that MDM is preferable and practicable.

  13. Resistance welding of tubes at low regidual pressure jn tube cavity

    International Nuclear Information System (INIS)

    The procedure of butt resistance welding of boilers in diameter of 32 mm at low residual pressure in tube cavities has been studied. It is shown that the creation of low residual pressure in tube cavity makes it possible to produce qualitative joints of tubes of the 20, 12Kh1MF, 12Kh18N12T steels. The maximum relative deformation in the butt zone should be in the range of 0.5...0.6

  14. Hot-state experiment on double-pipe heat exchanger under coupled effect of fouling and acid%积灰与酸耦合作用下套管换热器传热特性热态实验

    Institute of Scientific and Technical Information of China (English)

    李飞; 孙奉仲; 史月涛

    2014-01-01

    Flue gas dew point is the key indicator of low temperature corrosion, and restricts deep utilization of boiler flue gas heat. Fouling of heat exchanger surface is a major factor in deterioration of heat transfer. When fluid flows across heat exchange tubes, fouling and acid condensation influence heat transfer of heat exchanger. In the flue gas environment with dust and acid, a hot-state test was conducted to analyze heat transfer characteristics at different outer wall temperatures, and the dew point of flue gas for engineering application was obtained with a higher use value. The influence of the tubes’ heat transfer characteristics with varying fouling and acid condensation was determined. Ash deposition with different amounts of acid condensation was investigated through analyzing the ash samples at different outer wall temperatures. The value of applied dew point for engineering was given as 72℃, which was at least 35℃ lower than the acid dew point in thermodynamics.%烟气露点是低温腐蚀的关键指标,制约着锅炉尾部排烟余热的深度利用。换热器表面积灰是传热特性恶化的主要原因,电站锅炉尾部烟气环境中,积灰与酸凝结共同作用影响换热器的传热特性。在含尘、含酸的烟气环境下对换热器传热特性进行热态实验研究,以套管换热器为基础,得到具有更高使用价值的烟气工程应用露点,结合传热特性随外壁温的变化情况,得到换热管传热特性随积灰及酸耦合的变化规律;并通过对不同外壁温下灰样的分析,得到不同酸凝结状况下积灰规律,得到实验环境下的工程应用酸露点温度为72℃,较传统热力学酸露点低35℃以上。

  15. Heat transfer performance of condenser tubes in an MSF desalination system

    International Nuclear Information System (INIS)

    The present research examines the amount of condensed fresh water off the outer-side surface of heat exchangers in an MSF system. The quantitative modeling of condensed water on the outer surface of comparable tubes, enhanced and plain, in a simulated MSF technique is investigated. An adapted simulation design on a test-rig facility, accounting for the condenser tubing in actual industrial desalination plate-form, is used with corrugated and smooth aluminum-brass material tubes 1100mm long and 23mm bore. A single phase flow of authentic brine water that typifies real fouling is utilized to simulate the actual environmental life of a multi-stage flashing desalination system, with coolant flow velocity 0.1 m/s in the two delineated types of condenser tubing. It is demonstrated that the condensate water amount from the specified enhanced tube is about 1.22 times the condensate water amount from the smooth tube, adaptive for 140 running hours under deliberated constrains. The topic covers a comparative analysis of thermal performance. Comparing results with fresh water confirm the effect of fouling on significantly lowering the value of the overall heat transfer coefficient versus time. Fouling resistance Rf is reported with the critical coolant flow speed of 0.1 m/s. Comparison between the fouling resistance for both smooth and corrugated tubes versus time is performed. The fouling thermal resistance of the corrugated tube is 0.56 of the fouling thermal resistance of the smooth tube after140 running hours of the experiment are concluded. Overall, in the case of real brine, results prove that heat performance for the corrugated tube is superior to the plain tube over the studied time period (140 hrs) for the chosen range of flow speeds

  16. Fouling corrosion in aluminum heat exchangers

    Directory of Open Access Journals (Sweden)

    Su Jingxin

    2015-06-01

    Full Text Available Fouling deposits on aluminum heat exchanger reduce the heat transfer efficiency and cause corrosion to the apparatus. This study focuses on the corrosive behavior of aluminum coupons covered with a layer of artificial fouling in a humid atmosphere by their weight loss, Tafel plots, electrochemical impedance spectroscopy (EIS, and scanning electron microscope (SEM observations. The results reveal that chloride is one of the major elements found in the fouling which damages the passive film and initiates corrosion. The galvanic corrosion between the metal and the adjacent carbon particles accelerates the corrosive process. Furthermore, the black carbon favors the moisture uptake, and gives the dissolved oxygen greater chance to migrate through the fouling layer and form a continuous diffusive path. The corrosion rate decreasing over time is conformed to electrochemistry measurements and can be verified by Faraday’s law. The EIS results indicate that the mechanism of corrosion can be interpreted by the pitting corrosion evolution mechanism, and that pitting was observed on the coupons by SEM after corrosive exposure.

  17. Superheater corrosion in kraft recovery boilers; Korrosion hos oeverhettare i sodapannor. En oeversikt och diskussion

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, F. [AaF-IPK, Stockholm (Sweden)

    1997-02-01

    Corrosion seems to be the most essential factor limiting the life and the availability of kraft recovery boilers. The steam temperature from the kraft recovery boiler has, seen from the view of electricity production and steam turbine operation, traditionally been kept moderate, especially in comparison with steam data from normal utility power plants. So the corrosion of the superheaters has been more a limitation for the temperature of the steam produced by the boiler than a life length limitation. Both the pressure and the temperature of the steam are limited by corrosion. The temperature of the boiling water, and hence the pressure, is limited by the corrosion in the lower furnace. The temperature of the steam is limited by the corrosion in the superheater. Kraft boiler superheater corrosion is here governed not only by the boiler design, but more by the mill chemistry and boiler operation practice. This report discusses the formation and the properties of the deposits and their relation to boiler operation and the corrosion of the superheater tube material. We have tried to understand the corrosion in the kraft boiler superheaters better by comparing with the experience from the utility boilers. 86 refs, 79 figs

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. New technique of the local heat flux measurement in combustion chambers of steam boilers

    Science.gov (United States)

    Taler, Jan; Taler, Dawid; Sobota, Tomasz; Dzierwa, Piotr

    2011-12-01

    A new method for measurement of local heat flux to water-walls of steam boilers was developed. A flux meter tube was made from an eccentric tube of short length to which two longitudinal fins were attached. These two fins prevent the boiler setting from heating by a thermal radiation from the combustion chamber. The fins are not welded to the adjacent water-wall tubes, so that the temperature distribution in the heat flux meter is not influenced by neighbouring water-wall tubes. The thickness of the heat flux tube wall is larger on the fireside to obtain a greater distance between the thermocouples located inside the wall which increases the accuracy of heat flux determination. Based on the temperature measurements at selected points inside the heat flux meter, the heat flux absorbed by the water-wall, heat transfer coefficient on the inner tube surface and temperature of the water-steam mixture was determined.

  20. CROSS-FLOW ULTRAFILTRATION OF SECONDARY EFFLUENTS. MEMBRANE FOULING ANALYSIS

    Directory of Open Access Journals (Sweden)

    Luisa Vera

    2014-12-01

    Full Text Available The application of cross-flow ultrafiltration to regenerate secondary effluents is limited by membrane fouling. This work analyzes the influence of the main operational parameters (transmembrane pressure and cross-flow velocity about the selectivity and fouling observed in an ultrafiltration tubular ceramic membrane. The experimental results have shown a significant retention of the microcolloidal and soluble organic matter (52 – 54% in the membrane. The fouling analysis has defined the critical operational conditions where the fouling resistance is minimized. Such conditions can be described in terms of a dimensionless number known as shear stress number and its relationship with other dimensionless parameter, the fouling number.

  1. Fouling and Antifouling of Depetanizer in Ethylene Units

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Factors affecting fouling of depentanizer in ethylene units were explored through study of thecomposition of pyrolysis gasoline, C5 distillate and fouling deposits from the depentanizer while takinginto consideration the processing parameters. A variety of antifouling measures, in particular the injec-tion of a special anti-fouling agent into the Cs gas phase pipeline and the C5 distillate reflux pipelinewere introduced. Commercial evaluation test of a multifunctional anti-fouling agent, the RIPP-1404anti-fouling agent, was also described.

  2. The Modified Fouling Index Ultrafiltration constant flux for assessing particulate/colloidal fouling of RO systems

    KAUST Repository

    Salinas-Rodriguez, Sergio G.

    2015-02-18

    Reliable methods for measuring and predicting the fouling potential of reverse osmosis (RO) feed water are important in preventing and diagnosing fouling at the design stage, and for monitoring pre-treatment performance during plant operation. The Modified Fouling Index Ultrafiltration (MFI-UF) constant flux is a significant development with respect to assessing the fouling potential of RO feed water. This research investigates (1) the variables influencing the MFI-UF test at constant flux filtration (membrane pore size, membrane material, flux rate); and (2) the application of MFI-UF into pre-treatment assessment and RO fouling estimation. The dependency of MFI on flux, means that to assess accurately particulate fouling in RO systems, the MFI should be measured at a flux similar to a RO system (close to 20 L/m2/h) or extrapolated from higher fluxes. The two studied membrane materials showed reproducible results; 10% for PES membranes and 6.3% for RC membranes. Deposition factors (amount of particles that remain on the surface of membrane) were measured in a full-scale plant ranging between 0.2 and 0.5. The concept of “safe MFI” is presented as a guideline for assessing pre-treatment for RO systems.

  3. Mitigation of Syngas Cooler Plugging and Fouling

    Energy Technology Data Exchange (ETDEWEB)

    Bockelie, Michael J. [Reaction Engineering International, Salt Lake City, UT (United States)

    2015-06-29

    This Final Report summarizes research performed to develop a technology to mitigate the plugging and fouling that occurs in the syngas cooler used in many Integrated Gasification Combined Cycle (IGCC) plants. The syngas cooler is a firetube heat exchanger located downstream of the gasifier. It offers high thermal efficiency, but its’ reliability has generally been lower than other process equipment in the gasification island. The buildup of ash deposits that form on the fireside surfaces in the syngas cooler (i.e., fouling) lead to reduced equipment life and increased maintenance costs. Our approach to address this problem is that fouling of the syngas cooler cannot be eliminated, but it can be better managed. The research program was funded by DOE using two budget periods: Budget Period 1 (BP1) and Budget Period 2 (BP2). The project used a combination of laboratory scale experiments, analysis of syngas cooler deposits, modeling and guidance from industry to develop a better understanding of fouling mechanisms and to develop and evaluate strategies to mitigate syngas cooler fouling and thereby improve syngas cooler performance. The work effort in BP 1 and BP 2 focused on developing a better understanding of the mechanisms that lead to syngas cooler plugging and fouling and investigating promising concepts to mitigate syngas cooler plugging and fouling. The work effort focused on the following: • analysis of syngas cooler deposits and fuels provided by an IGCC plant collaborating with this project; • performing Jet cleaning tests in the University of Utah Laminar Entrained Flow Reactor to determine the bond strength between an ash deposit to a metal plate, as well as implementing planned equipment modifications to the University of Utah Laminar Entrained Flow Reactor and the one ton per day, pressurized Pilot Scale Gasifier; • performing Computational Fluid Dynamic modeling of industrially relevant syngas cooler configurations to develop a better

  4. Numerical simulation based cold tests for a tangentially fired boiler

    Institute of Scientific and Technical Information of China (English)

    XIANG Yuhua; ZHANG Jiayuan; ZHANG Xiaohui

    2012-01-01

    Such problems as flameout and serious slagging frequently occurred in a 170 t/h tangentially fired boiler burning inferior coals and with low load.Thus,cold tests were carried out to comprehensively investigate the performance of each air tube and the size and position of the tangential circle.Therefore,the cause and area of slagging in furnace can be determined.Thus,by numerical simulation on combustion,the optimal operation parameters for the boiler burning different coals under various loads conditions can be provided.The actual application showed that,the boiler fed with present coal can be long-term operated stably at 60% load,and its heat efficiency was up to 91%.Moreover,the abnormal flameout no longer occurred,and the slagging was alleviated a lot.

  5. Selecting the right material for recovery boiler superheaters

    Energy Technology Data Exchange (ETDEWEB)

    Vakkilainen, E. K. (Lappeenranta Univ. of Technology (Finland)); Pohjanne, P. (VTT Technical Research Centre of Finland, Espoo (Finland))

    2010-05-15

    The aim of this paper is to examine the selection of superheater materials for recovery boilers. Fireside wastage in recovery boilers is mainly caused by formation of corrosive deposits, typically with aggressive molten alkali phases. Fireside corrosion can also be caused by gaseous components and is then usually associated with a reducing atmosphere. This active oxidation can affect superheater tubes even at temperatures lower than the first melting temperature. There is a wide array of available superheater materials to choose from and a few newer materials to be considered. The operating conditions and deposit properties must be looked at when material selection is done. The material choice has a significant effect to the cost of the recovery boiler, as the selection of the final superheater material can change the price by a factor of 10. (orig.)

  6. High-Temperature Graphitization Failure of Primary Superheater Tube

    Science.gov (United States)

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

    2015-12-01

    Failure of boiler tubes is the main cause of unit outages of the plant, which further affects the reliability, availability and safety of the unit. So failure analysis of boiler tubes is absolutely essential to predict the root cause of the failure and the steps are taken for future remedial action to prevent the failure in near future. This paper investigates the probable cause/causes of failure of the primary superheater tube in a thermal power plant boiler. Visual inspection, dimensional measurement, chemical analysis, metallographic examination and hardness measurement are conducted as the part of the investigative studies. Apart from these tests, mechanical testing and fractographic analysis are also conducted as supplements. Finally, it is concluded that the superheater tube is failed due to graphitization for prolonged exposure of the tube at higher temperature.

  7. Model-Based Water Wall Fault Detection and Diagnosis of FBC Boiler Using Strong Tracking Filter

    OpenAIRE

    Li Sun; Junyi Dong; Donghai Li; Yuqiong Zhang

    2014-01-01

    Fluidized bed combustion (FBC) boilers have received increasing attention in recent decades. The erosion issue on the water wall is one of the most common and serious faults for FBC boilers. Unlike direct measurement of tube thickness used by ultrasonic methods, the wastage of water wall is reconsidered equally as the variation of the overall heat transfer coefficient in the furnace. In this paper, a model-based approach is presented to estimate internal states and heat transfer coefficient d...

  8. The effect of water quality on reliability of boiler plants performance

    OpenAIRE

    Gajić Anto S.; Tomić Milorad V.; Pavlović Ljubica J.; Pavlović Miomir G.

    2010-01-01

    This paper presents sources and types of corrosion processes of boiler tube system of the Thermal Power Plant "Ugljevik". The main goal in the electric power production is to achieve lower prices, which can only be done by providing low maintenance costs. While it is not possible to completely stop corrosion, it could be slowed down and it's effects could be reduced. In order to reduce corrosion to a minimum on thermal power plants' vital equipment, particularly boilers, it is necessary to de...

  9. Analysis on Bust Problem of 12Cr1MoV High Temperature Superheater Tubes of Boiler%锅炉用12Cr1MoV 高温段过热管爆裂分析

    Institute of Scientific and Technical Information of China (English)

    刘长春; 沈玉力

    2014-01-01

    The burst reason of 12Cr1MoV steel tube of high temperature superheater tubes of a power plant was analyzed through macroscopic and metallographic examination .The results showed that local corrosion in high temperature led to mul-tiple cross crack sources , and propagation of the cracks caused vertical cracks to the same radial direction in two places . Local corrosion in high temperature and fully nodular pearlite were the root cause of the failure .%某电厂的12Cr1MoV(φ42×5mm)高温段过热器管发生爆裂。采用宏观和微观分析方法,分析了爆裂原因。结果表明,该爆裂模式为局部高温腐蚀引发多处横裂源进一步导致2处同一径向的纵裂。局部高温腐蚀及珠光体完全球化是这起事故的根本原因。

  10. Super Boiler 2nd Generation Technology for Watertube Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Mr. David Cygan; Dr. Joseph Rabovitser

    2012-03-31

    This report describes Phase I of a proposed two phase project to develop and demonstrate an advanced industrial watertube boiler system with the capability of reaching 94% (HHV) fuel-to-steam efficiency and emissions below 2 ppmv NOx, 2 ppmv CO, and 1 ppmv VOC on natural gas fuel. The boiler design would have the capability to produce >1500 F, >1500 psig superheated steam, burn multiple fuels, and will be 50% smaller/lighter than currently available watertube boilers of similar capacity. This project is built upon the successful Super Boiler project at GTI. In that project that employed a unique two-staged intercooled combustion system and an innovative heat recovery system to reduce NOx to below 5 ppmv and demonstrated fuel-to-steam efficiency of 94% (HHV). This project was carried out under the leadership of GTI with project partners Cleaver-Brooks, Inc., Nebraska Boiler, a Division of Cleaver-Brooks, and Media and Process Technology Inc., and project advisors Georgia Institute of Technology, Alstom Power Inc., Pacific Northwest National Laboratory and Oak Ridge National Laboratory. Phase I of efforts focused on developing 2nd generation boiler concepts and performance modeling; incorporating multi-fuel (natural gas and oil) capabilities; assessing heat recovery, heat transfer and steam superheating approaches; and developing the overall conceptual engineering boiler design. Based on our analysis, the 2nd generation Industrial Watertube Boiler when developed and commercialized, could potentially save 265 trillion Btu and $1.6 billion in fuel costs across U.S. industry through increased efficiency. Its ultra-clean combustion could eliminate 57,000 tons of NOx, 460,000 tons of CO, and 8.8 million tons of CO2 annually from the atmosphere. Reduction in boiler size will bring cost-effective package boilers into a size range previously dominated by more expensive field-erected boilers, benefiting manufacturers and end users through lower capital costs.

  11. A review on biomass as a fuel for boilers

    Energy Technology Data Exchange (ETDEWEB)

    Saidur, R.; Abelaziz, E.A.; Demirbas, A.; Hossain, M.S.; Mekhilef, S. [University of Malaya, Kuala Lumpur (Malaysia). Dept. of Mechanical Engineering

    2011-06-15

    Currently, fossil fuels such as oil, coal and natural gas represent the prime energy sources in the world. However, it is anticipated that these sources of energy will deplete within the next 40-50 years. Moreover, the expected environmental damages such as the global warming, acid rain and urban smog due to the production of emissions from these sources have tempted the world to try to reduce carbon emissions by 80% and shift towards utilizing a variety of renewable energy resources (RES) which are less environmentally harmful such as solar, wind, biomass etc. in a sustainable way. Biomass is one of the earliest sources of energy with very specific properties. In this review, several aspects which are associated with burning biomass in boilers have been investigated such as composition of biomass, estimating the higher heating value of biomass, comparison between biomass and other fuels, combustion of biomass, co-firing of biomass and coal, impacts of biomass, economic and social analysis of biomass, transportation of biomass, densification of biomass, problems of biomass and future of biomass. It has been found that utilizing biomass in boilers offers many economical, social and environmental benefits such as financial net saving, conservation of fossil fuel resources, job opportunities creation and CO{sub 2} and NO emissions reduction. However, care should be taken to other environmental impacts of biomass such as land and water resources, soil erosion, loss of biodiversity and deforestation. Fouling, marketing, low heating value, storage and collections and handling are all associated problems when burning biomass in boilers. The future of biomass in boilers depends upon the development of the markets for fossil fuels and on policy decisions regarding the biomass market.

  12. 我国700℃超超临界锅炉过热器管用高温合金选材探讨%Selection of Superalloys for Superheater Tubes of Domestic 700 ℃ A-USC Boilers

    Institute of Scientific and Technical Information of China (English)

    林富生; 谢锡善; 赵双群; 董建新

    2011-01-01

    简要介绍和比较了国内外700℃超超临界电站过热器和再热器管候选材料GH2984、Haynes 230、CCA 617、Nimonic 263、Inconel 740及其改型合金Inconel 740H的组织、持久强度和耐腐蚀性能等研究结果,对几种材料的强度、耐腐蚀性能、工艺性能和使用经济性进行了分析,并阐述了中国在发展700℃超超临界燃煤电站时锅炉用高温合金的选择.结果表明:Inconel 740H合金具有的持久强度最高、耐蚀性能最好,工艺性能和使用经济性良好,比Inconel 740合金具有更好的长期组织稳定性,它应是中国700℃超超临界锅炉过热器和再热器首选的管材;针对700℃超超临界机组用关键材料,提出了尽早开展自主研制,实现关键材料国产化的建议.%Research achievements on major candidate materials for superheater/reheater tubes of plants at home and abroad are reviewed and compared,such as the GH2984,Haynes 230,CCA 617,Nimonic 263,Inconel 740 and Inconel 740H,while their microstructure,stress rupture strength and corrosion resistance as well as their workability and economy were analyzed.A discussion is moreover carried out to the selection of superalloys for superheater/reheater tubes of domestic 700 ℃ A-USC power plants.Results show that superalloy Inconel 740H exhibits the highest stress rupture strength,strongest corrosion resistance,better workability and economy among above six alloys;its microstructure is more stable than that of Inconel 740 during long term aging,which is therefore at present believed to be most preferable for superheater/reheater tubes of domestic 700 ℃ A-USC power plants.For localization of key materials for relevant power plants,it is suggested that RD on these materials should be performed as early as possible.

  13. The recovery boiler advisor. Combination of practical experience and advanced thermodynamic modelling

    Energy Technology Data Exchange (ETDEWEB)

    Backman, R. [Aabo Akademi, Turku (Finland); Eriksson, G. [LTH/RWTH (Germany); Sundstroem, K. [Tampella Power Oy, Tampere (Finland)

    1996-12-31

    The Aabo Advisor is a computer based program intended to provide information about the high temperature ash and fluegas chemistry in pulping spent black liquor recovery boilers of kraft pulp mills. The program can be used for predictions of a variety of furnace and flue gas phenomena, such as fireside fouling of the heat exchanger surfaces caused by the flue gas particulate matter, emissions of SO{sub 2}(g), HCl(g) and NO{sub x}(g) with the flue gas etc. The program determines the composition of the fluegas as well as the amount and composition of the two typical fly ash fractions found in recovery boiler fluegases, the condensed fly ash particles and the carry over particles. These data are used for calculating the melting behavior of the fly ash present at different locations in the boiler and this characteristic behavior is used for the fireside fouling predictions. The program may also be used for studying how different mill processes affecting the black liquor composition affects on the fireside chemistry of the recovery boiler. As input data for the calculations only a few boiler operation parameters and the composition of the black liquor is required. The calculations are based on a one-dimensional, multi-stage chemistry model where both thermodynamic equilibrium calculations and stoichiometric material balances are used. The model calculates at first the chemistry in the lower furnace and smelt after which it moves to the upper furnace and the radiative parts of the fluegas channel. As the last block the program calculates the chemistry in the convective part, the electrostatic precipitator cath and stack. The results from each block are presented in tables, key numbers and melt curves representing the fluegas or fly ash fraction present at each location

  14. Small boiler uses waste coal

    Energy Technology Data Exchange (ETDEWEB)

    Virr, M.J. [Spinheat Ltd. (United States)

    2009-07-15

    Burning coal waste in small boilers at low emissions poses considerable problem. While larger boiler suppliers have successfully installed designs in the 40 to 80 MW range for some years, the author has been developing small automated fluid bed boiler plants for 25 years that can be applied in the range of 10,000 to 140,000 lbs/hr of steam. Development has centered on the use of an internally circulating fluid bed (CFB) boiler, which will burn waste fuels of most types. The boiler is based on the traditional D-shaped watertable boiler, with a new type of combustion chamber that enables a three-to-one turndown to be achieved. The boilers have all the advantages of low emissions of the large fluid boilers while offering a much lower height incorporated into the package boiler concept. Recent tests with a waste coal that had a high nitrogen content of 1.45% demonstrated a NOx emission below the federal limit of 0.6 lbs/mm Btu. Thus a NOx reduction on the order of 85% can be demonstrate by combustion modification alone. Further reductions can be made by using a selective non-catalytic reduction (SNCR) system and sulfur absorption of up to 90% retention is possible. The article describes the operation of a 30,000 lbs/hr boiler at the Fayette Thermal LLC plant. Spinheat has installed three ICFB boilers at a nursing home and a prison, which has been tested on poor-grade anthracite and bituminous coal. 2 figs.

  15. Fouling resistance prediction using artificial neural network nonlinear auto-regressive with exogenous input model based on operating conditions and fluid properties correlations

    Science.gov (United States)

    Biyanto, Totok R.

    2016-06-01

    Fouling in a heat exchanger in Crude Preheat Train (CPT) refinery is an unsolved problem that reduces the plant efficiency, increases fuel consumption and CO2 emission. The fouling resistance behavior is very complex. It is difficult to develop a model using first principle equation to predict the fouling resistance due to different operating conditions and different crude blends. In this paper, Artificial Neural Networks (ANN) MultiLayer Perceptron (MLP) with input structure using Nonlinear Auto-Regressive with eXogenous (NARX) is utilized to build the fouling resistance model in shell and tube heat exchanger (STHX). The input data of the model are flow rates and temperatures of the streams of the heat exchanger, physical properties of product and crude blend data. This model serves as a predicting tool to optimize operating conditions and preventive maintenance of STHX. The results show that the model can capture the complexity of fouling characteristics in heat exchanger due to thermodynamic conditions and variations in crude oil properties (blends). It was found that the Root Mean Square Error (RMSE) are suitable to capture the nonlinearity and complexity of the STHX fouling resistance during phases of training and validation.

  16. Proteins causing membrane fouling in membrane bioreactors.

    Science.gov (United States)

    Miyoshi, Taro; Nagai, Yuhei; Aizawa, Tomoyasu; Kimura, Katsuki; Watanabe, Yoshimasa

    2015-01-01

    In this study, the details of proteins causing membrane fouling in membrane bioreactors (MBRs) treating real municipal wastewater were investigated. Two separate pilot-scale MBRs were continuously operated under significantly different operating conditions; one MBR was a submerged type whereas the other was a side-stream type. The submerged and side-stream MBRs were operated for 20 and 10 days, respectively. At the end of continuous operation, the foulants were extracted from the fouled membranes. The proteins contained in the extracted foulants were enriched by using the combination of crude concentration with an ultrafiltration membrane and trichloroacetic acid precipitation, and then separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). The N-terminal amino acid sequencing analysis of the proteins which formed intensive spots on the 2D-PAGE gels allowed us to partially identify one protein (OmpA family protein originated from genus Brevundimonas or Riemerella anatipestifer) from the foulant obtained from the submerged MBR, and two proteins (OprD and OprF originated from genus Pseudomonas) from that obtained from the side-stream MBR. Despite the significant difference in operating conditions of the two MBRs, all proteins identified in this study belong to β-barrel protein. These findings strongly suggest the importance of β-barrel proteins in developing membrane fouling in MBRs.

  17. Coke fouling monitoring by electrical resistivity

    Energy Technology Data Exchange (ETDEWEB)

    Bombardelli, Clovis; Mari, Livia Assis; Kalinowski, Hypolito Jose [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Programa de Pos-Graduacao em Engenharia Eletrica e Informatica Industrial (CPGEI)

    2008-07-01

    An experimental method to simulate the growth of the coke fouling that occurs in the oil processing is proposed relating the thickness of the encrusted coke to its electrical resistivity. The authors suggest the use of the fouling electrical resistivity as a transducer element for determining its thickness. The sensor is basically two electrodes in an electrically isolated device where the inlay can happen in order to compose a purely resistive transducer. Such devices can be easily constructed in a simple and robust form with features capable to face the high temperatures and pressures found in relevant industrial processes. For validation, however, it is needed a relationship between the electrical resistivity and the fouling thickness, information not yet found in the literature. The present work experimentally simulates the growth of a layer of coke on an electrically insulating surface, equipped with electrodes at two extremities to measure the electrical resistivity during thermal cracking essays. The method is realized with a series of consecutive runs. The results correlate the mass of coke deposited and its electrical resistivity, and it can be used to validate the coke depositions monitoring employing the resistivity as a control parameter. (author)

  18. Boilers a practical reference

    CERN Document Server

    Rayaprolu, Kumar

    2012-01-01

    AAbrasion and Abrasion Index (see Wear)Absolute or Dynamic Viscosity (æ) (see Viscosity in Fluid Characteristics)Acid Cleaning (see Commissioning)Acid Rain (also see Air Pollution Emissions and Controls and Gas Cleaning)Acid Sludge (see Refuse Fuels from Refinery in Liquid Fuels)Acid Smuts (see Oil Ash)Acoustic Soot Blowers (see Sonic Horns)Acoustic Enclosure (see Noise Control)Acoustic Leak Detection SystemAdiabatic Flame Temperature (see Combustion)Aeroderivative (see Types of GTs in Turbines, Gas)Ageing of Boiler ComponentsAgro-Fuels and FiringAir Ducts (see Draught Plant)Air Flow Measureme

  19. COMBINED BOILER WITH TPV

    OpenAIRE

    Björk, Magnus

    2013-01-01

    A TPV-system consists of a hot surface emitting heat radiation on a solar cell with a narrow bandgap.  A unit consisting of a boiler and a TPV-system has been constructed for testing of the performance of TPV cells. The emitter is heated by a fuel consisting of RME-oil. The radiation is collected and concentrated through two reflecting cones formed like a Faberge-egg, with an edge-type optical filter between the cones. The Faberge-egg is treated with electro-polishing in order to obtain a hig...

  20. [A novel approach of using fouling index to evaluate NOM fouling behavior during low pressure ultrafiltration process].

    Science.gov (United States)

    Xiao, Ping; Xiao, Feng; Zhao, Jing-Hui; Qin, Tong; Wang, Dong-Sheng; Feng, Jin-Rong; Xu, Guang

    2012-12-01

    In this study, fouling index (FI) was introduced as a novel approach to investigate NOM fouling behavior during low pressure membrane ultrafiltration process. Three kinds of typical NOMs, humic acid (HA), bovine serum albumin (BSA) and sodium alginate (NaAlg), were used in the experiments. The results indicated that the fouling caused by NOM can be considered as two steps with different FI values. One is the fast fouling phase, and the other is the slow phase. Apparently, the total fouling index of the fast phase (TFI(F)) was much greater than that of the slow phase (TFI(S)), which means the initial interaction between NOM and membrane would play a significant role in the whole fouling process. A higher TFI(F) could lead to a faster fouling and the flux would decline more rapidly. After hydraulic washing, the flux was recovered and the resistance was reduced, indicating that physical cleaning could remove a part of foulants. Additionally, the results also represented that the sequences of NOM causing irreversible fouling and chemical clean irreversible fouling were BSA > HA > NaAlg and NaAlg > BSA > HA, respectively. Humic acid and protein tended to cause irreversible fouling and were easily removed by alkaline cleaning, while irreversible fouling caused by polysaccharide was difficult to remove by alkaline. The main cause of membrane fouling may be the interaction between foulants and membrane, which needs further research. Generally speaking, FI with a simple expression would play a significant role to describe the membrane fouling. PMID:23379159

  1. CFD simulations of heat transfer in internally helically ribbed tubes

    Directory of Open Access Journals (Sweden)

    Majewski Karol

    2016-06-01

    Full Text Available Heating surfaces in power boilers are exposed to very high heat flux. For evaporator protection against overheating, internally helically ribbed tubes are used. The intensification of the heat transfer and the maintenance of the thin water layer in the intercostal space, using ribbed tubes, enables better protection of the power boiler evaporator than smooth pipes. Extended inner surface changes flow and thermal conditions by influencing the linear pressure drop and heat transfer coefficient. This paper presents equations that are used to determine the heat transfer coefficient. The results of total heat transfer, obtained from CFD simulations, for two types of internally ribbed and plain tubes are also presented.

  2. Identification of Material Parameters for the Simulation of Acoustic Absorption of Fouled Sintered Fiber Felts

    Directory of Open Access Journals (Sweden)

    Nicolas Lippitz

    2016-08-01

    Full Text Available As a reaction to the increasing noise pollution, caused by the expansion of airports close to residential areas, porous trailing edges are investigated to reduce the aeroacoustic noise produced by flow around the airframe. Besides mechanical and acoustical investigations of porous materials, the fouling behavior of promising materials is an important aspect to estimate the performance in long-term use. For this study, two sintered fiber felts were selected for a long-term fouling experiment where the development of the flow resistivity and accumulation of dirt was observed. Based on 3D structural characterizations obtained from X-ray tomography of the initial materials, acoustic models (Biot and Johnson–Champoux–Allard in the frame of the transfer matrix method were applied to the sintered fiber felts. Flow resistivity measurements and the measurements of the absorption coefficient in an impedance tube are the basis for a fouling model for sintered fiber felts. The contribution will conclude with recommendations concerning the modeling of pollution processes of porous materials.

  3. Analysis of fouling mechanisms in anaerobic membrane bioreactors

    OpenAIRE

    Charfi, Amine; Ben Amar, Nihel; Harmand, Jérôme

    2012-01-01

    In this paper, we investigate the fouling mechanisms responsible for MF and UF membrane flux decline in Anaerobic Membrane Bioreactors (AnMBR). We have used the fouling mechanism models proposed by Hermia (1982), namely pore constriction, cake formation, complete blocking and intermediate blocking. Based on an optimization approach and using experimental data extracted from the literature, we propose a systematic procedure for identifying the most likely fouling mechanism in play. Short-term ...

  4. Measurements of absorbed heat flux and water-side heat transfer coefficient in water wall tubes

    Science.gov (United States)

    Taler, Jan; Taler, Dawid; Kowal, Andrzej

    2011-04-01

    The tubular type instrument (flux tube) was developed to identify boundary conditions in water wall tubes of steam boilers. The meter is constructed from a short length of eccentric tube containing four thermocouples on the fire side below the inner and outer surfaces of the tube. The fifth thermocouple is located at the rear of the tube on the casing side of the water-wall tube. The boundary conditions on the outer and inner surfaces of the water flux-tube are determined based on temperature measurements at the interior locations. Four K-type sheathed thermocouples of 1 mm in diameter, are inserted into holes, which are parallel to the tube axis. The non-linear least squares problem is solved numerically using the Levenberg-Marquardt method. The heat transfer conditions in adjacent boiler tubes have no impact on the temperature distribution in the flux tubes.

  5. Pellet wood gasification boiler / Combination boiler. Market review. 7. ed.; Scheitholzvergaser-/Kombikessel. Marktuebersicht

    Energy Technology Data Exchange (ETDEWEB)

    Uth, Joern

    2010-08-15

    In the market review under consideration on pellet wood gasification boilers and combination boilers, the Federal Ministry of Food, Agriculture and Consumer Protection (Bonn, Federal Republic of Germany) report on planning and installation of wood-fired heating systems, recommendations regarding to the technical assessment of boiler systems, buffers/combination boilers, prices of pellet wood gasification boilers, data sheets of the compared pellet wood gasification boilers, pellet wood combination boilers, prices of pellet wood combination boilers, data sheets of the compared pellet wood gasification boilers, list of providers.

  6. Market review. Pellet wood gasification boiler / combination boiler. 8. ed.; Marktuebersicht. Scheitholzvergaser-/Kombikessel

    Energy Technology Data Exchange (ETDEWEB)

    Uth, Joern

    2012-01-15

    In the market review under consideration on pellet wood gasification boilers and combination boilers, the Federal Ministry of Food, Agriculture and Consumer Protection (Bonn, Federal Republic of Germany) reports on planning and installation of wood-fired heating systems, recommendations regarding to the technical assessment of boiler systems, buffers/combination boilers, prices of pellet wood gasification boilers, data sheets of the compared pellet wood gasification boilers, pellet wood combination boilers, prices of pellet wood combination boilers, data sheets of the compared pellet wood gasification boilers, list of providers.

  7. Economic evaluation of losses to electric power utilities caused by ash fouling. Final technical report, November 1, 1979-April 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Burkhardt, F.R.; Persnger, M.M.

    1980-01-01

    Problems with convection ash fouling and wall slagging were considerable during our study. The Dakota lignites posed the greatest problems, particularly with fouling. The subbituminous coals had considerable problems, related mostly with wall slagging. The Texas lignites had few problems, and those were only associated with wall slagging. The generation losses were as follows: The Dakota lignite burning stations averaged an overall availability of 87.13%. Convection fouling outages were responsible for 57.75% of this outage time for a decrease in availability of 7.43%. Fouling was responsible for curtailment losses of 317,649 Mwh or 8.25% of the remaining available generation. Slagging was responsible for losses of 2732 megawatt hours or .07% of the remaining available generation. Total ash related losses amounted to 16.08% of the total available generation. The subbituminous burning stations averaged an overall availability of 78.36%. Total ash related losses amounted to 1.54% of the total available generation. The Texas lignite burning stations averaged an overall availability of 80.63%. No ash related outage losses occurred. Slagging curtailments accounted 0.08% of the total available generation. Costs due to ash fouling and slagging related curtailments are a tremendous sum. Seven power stations were studied for a six month period to assess costs. The total cost directly attributable to ash slagging and fouling condition was $20,638,113. Recommendations for reducing the problems involve soot blowers, control of furnace gas exit temperature, water blowers and more conservative boiler design.

  8. Alternate tube plugging criteria for steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Cueto-Felgueroso, C.; Aparicio, C.B. [Tecnatom, S.A., Madrid (Spain)

    1997-02-01

    The tubing of the Steam Generators constitutes more than half of the reactor coolant pressure boundary. Specific requirements governing the maintenance of steam generator tubes integrity are set in Plant Technical Specifications and in Section XI of the ASME Boiler and Pressure Vessel Code. The operating experience of Steam Generator tubes of PWR plants has shown the existence of some types of degradatory processes. Every one of these has an specific cause and affects one or more zones of the tubes. In the case of Spanish Power Plants, and depending on the particular Plant considered, they should be mentioned the Primary Water Stress Corrosion Cracking (PWSCC) at the roll transition zone (RTZ), the Outside Diameter Stress Corrosion Cracking (ODSCC) at the Tube Support Plate (TSP) intersections and the fretting with the Anti-Vibration Bars (AVBs) or with the Support Plates in the preheater zone. The In-Service Inspections by Eddy Currents constitutes the standard method for assuring the SG tubes integrity and they permit the monitoring of the defects during the service life of the plant. When the degradation reaches a determined limit, called the plugging limit, the SG tube must be either repaired or retired from service by plugging. Customarily, the plugging limit is related to the depth of the defect. Such depth is typically 40% of the wall thickness of the tube and is applicable to any type of defect in the tube. In its origin, that limit was established for tubes thinned by wastage, which was the predominant degradation in the seventies. The application of this criterion for axial crack-like defects, as, for instance, those due to PWSCC in the roll transition zone, has lead to an excessive and unnecessary number of tubes being plugged. This has lead to the development of defect specific plugging criteria. Examples of the application of such criteria are discussed in the article.

  9. Erosion–corrosion behaviour of Ni-based superalloy Superni-75 in the real service environment of the boiler

    Indian Academy of Sciences (India)

    T S Sidhu; S Prakash; R D Agrawal; Ramesh Bhagat

    2009-04-01

    The super-heater and re-heater tubes of the boilers used in thermal power plants are subjected to unacceptable levels of surface degradation by the combined effect of erosion–corrosion mechanism, resulting in the tube wall thinning and premature failure. The nickel-based superalloys can be used as boiler tube materials to increase the service life of the boilers, especially for the new generation tra-supercritical boilers. The aim of the present investigation is to evaluate the erosion–corrosion behaviour of Ni-based superalloy Superni-75 in the real service environment of the coal-fired boiler of a thermal power plant. The cyclic experimental study was performed for 1000 h in the platen superheater zone of the coal-fired boiler where the temperature was around 900°C. The corrosion products have been characterized with respect to surface morphology, phase composition and element concentration using the combined techniques of X-ray diffractometry (XRD), scanning electron microscopy/energy-dispersive analysis (SEM/EDAX) and electron probe micro analyser (EPMA). The Superni-75 performed well in the coal-fired boiler environment, which has been attributed mainly to the formation of a thick band of chromium in scale due to selective oxidation of the chromium.

  10. 49 CFR 230.47 - Boiler number.

    Science.gov (United States)

    2010-10-01

    ..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Gauges § 230.47 Boiler number. (a) Generally. The builder's number of the boiler, if known, shall... 49 Transportation 4 2010-10-01 2010-10-01 false Boiler number. 230.47 Section...

  11. Study of Corrosion in a Biomass Boiler

    Directory of Open Access Journals (Sweden)

    C. Berlanga

    2013-01-01

    Full Text Available Biomass plants, apart from producing energy, help to reduce CO2(g emissions. One of the biggest problems for their development is superheater corrosion due to fuel corrosivity, especially of the straw. This limits both the temperature of the vapour and also the effectiveness of the plant. In order to know more about the reactions which happen inside the boiler of biomass, thermodynamic calculations using software (HSC Chemistry have been carried out. Field tests have been carried out in the Sangüesa Biomass Plant in Navarra (Spain: determination of the types of oxides and the deposits formed on the superheaters tubes as well as a program to measure temperatures. Finally, the global results are discussed.

  12. Membrane fouling potentials and cellular properties of bacteria isolated from fouled membranes in a MBR treating municipal wastewater.

    Science.gov (United States)

    Ishizaki, So; Fukushima, Toshikazu; Ishii, Satoshi; Okabe, Satoshi

    2016-09-01

    Membrane fouling remains a major challenge for wider application of membrane bioreactors (MBRs) to wastewater treatment. Membrane fouling is mainly caused by microorganisms and their excreted microbial products. For development of more effective control strategies, it is important to identify and characterize the microorganisms that are responsible for membrane fouling. In this study, 41 bacterial strains were isolated from fouled microfiltration membranes in a pilot-scale MBR treating real municipal wastewater, and their membrane fouling potentials were directly measured using bench-scale cross-flow membrane filtration systems (CFMFSs) and related to their cellular properties. It was found that the fouling potential was highly strain dependent, suggesting that bacterial identification at the strain level is essential to identify key fouling-causing bacteria (FCB). The FCB showed some common cellular properties. The most prominent feature of FCB was that they formed convex colonies having swollen podgy shape and smooth lustrous surfaces with high water, hydrophilic organic matter and carbohydrate content. However, general and rigid biofilm formation potential as determined by microtiter plates and cell surface properties (i.e., hydrophobicity and surface charge) did not correlate with the fouling potential in this study. These results suggest that the fouling potential should be directly evaluated under filtration conditions, and the colony water content could be a useful indicator to identify the FCB. PMID:27232989

  13. Hydraulically irreversible fouling on ceramic MF/UF membranes: comparison of fouling indices, foulant composition and irreversible pore narrowing

    KAUST Repository

    Shang, Ran

    2015-05-06

    The application of ceramic membranes in water treatment is becoming increasing attractive because of their long life time and excellent chemical, mechanical and thermal stability. However, fouling of ceramic membranes, especially hydraulically irreversible fouling, is still a critical aspect affecting the operational cost and energy consumption in water treatment plants. In this study, four ceramic membranes with pore sizes or molecular weight cut-off (MWCO) of 0.20 μm, 0.14 μm, 300 kDa and 50 kDa were compared during natural surface water filtration with respect to hydraulically irreversible fouling index (HIFI), foulant composition and narrowing of pore size due to the irreversible fouling. Our results showed that the hydraulically irreversible fouling index (HIFI) was proportional to the membrane pore size (r2=0.89) when the same feed water was filtrated. The UF membranes showed lower HIFI values than the MF membranes. Pore narrowing (internal fouling) was found to be a main fouling pattern of the hydraulically irreversible fouling. The internal fouling was caused by monolayer adsorption of foulants with different sizes that is dependent on the size of the membrane pore.

  14. 46 CFR 61.05-10 - Boilers in service.

    Science.gov (United States)

    2010-10-01

    ... INSPECTIONS Tests and Inspections of Boilers § 61.05-10 Boilers in service. (a) Each boiler, including superheater, reheater, economizer, auxiliary boiler, low-pressure heating boiler, and unfired steam boiler... 46 Shipping 2 2010-10-01 2010-10-01 false Boilers in service. 61.05-10 Section 61.05-10...

  15. 热循环对锅炉管热喷涂Ni-Cr基纳米涂层的影响%Effect of thermal cycle on Ni-Cr based nanostructured thermal spray coating in boiler tubes

    Institute of Scientific and Technical Information of China (English)

    V.SENTHILKUMAR; B.THIYAGARAJAN; M.DURAISELVAM; K.KARTHICK

    2015-01-01

    采用机械球磨法制备Ni-Cr基纳米原料粉末.粉末颗粒在行星球磨机中反复经历焊合、碎裂和重焊合过程.采用超音速火焰喷涂工艺(HVOF)在碳钢管上喷涂球磨纳米粉末.利用金相显微镜、XRD、扫描电子显微镜(SEM),高分辨透射电子显微镜(HR-TEM)、能谱(EDS)和显微硬度测试对原料粉和HVOF喷涂涂层进行表征.对喷涂和未喷涂试样进行热循环分析,研究相、冶金性能和显微硬度的变化.与传统喷涂试样相比,Ni-Cr纳米涂层试样具有更高的力学和冶金性能.与传统涂层相比,纳米涂层的显微组织更均匀和紧密.%Ni-Cr based nanostructured feedstock powder was prepared by mechanical milling technique involving repeated welding, fracturing, and re-welding of powder particles in a planetary ball mill. The milled nanocrystalline powders were used to coat carbon steel tubes using high velocity oxygen fuel (HVOF) thermal spraying process. The characterization of the feedstock powder and HVOF coated substrates was performed using optical microscope, X-ray diffractometer (XRD), scanning electron microscope (SEM), high resolution transmission electron microscope (HR-TEM), energy dispersive spectrometer (EDS) and microhardness tests. The coated and uncoated samples were subjected to different thermal cycles and characterized for their phase changes, metallurgical changes and microhardness variations. Ni-Cr nanostructured coated samples exhibited higher mechanical and metallurgical properties compared to their conventionally coated counter parts. The results showed that the nanostructured coating possessed a more uniform and denser microstructure than the conventional coating.

  16. Interaction of ions in water system containing copper-zinc alloy for boiler energy saving

    Institute of Scientific and Technical Information of China (English)

    MING Xing; LIANG Jinsheng; OU Xiuqin; TANG Qingguo; DING Yan

    2006-01-01

    Copper-zinc alloy element for boiler energy saving was put in the intake of simulated boiler system to investigate the interaction and transfer of ions in water system both theoretically and experimentally. The fouling was analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray detector (EDX). The results show that the transfer of calcium and magnesium ions in heat-transfer-surface-water system is affected by zinc ions dissolved from the alloy because of primary battery reaction. Some calcium ions of calcium carbonate crystal are replaced by zinc ions, the growth of aragonite crystal nucleus is retarded, and the transition of calcium carbonate from aragonite to calcite is hampered.

  17. Characterization of Oxy-combustion Impacts in Existing Coal-fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Bradley; Davis, Kevin; Senior, Constance; Shim, Hong Shim; Otten, Brydger; Fry, Andrew; Wendt, Jost; Eddings, Eric; Paschedag, Alan; Shaddix, Christopher; Cox, William; Tree, Dale

    2013-09-30

    Reaction Engineering International (REI) managed a team of experts from University of Utah, Siemens Energy, Praxair, Vattenfall AB, Sandia National Laboratories, Brigham Young University (BYU) and Corrosion Management Ltd. to perform multi-scale experiments, coupled with mechanism development, process modeling and CFD modeling, for both applied and fundamental investigations. The primary objective of this program was to acquire data and develop tools to characterize and predict impacts of CO{sub 2} flue gas recycle and burner feed design on flame characteristics (burnout, NO{sub x}, SO{sub x}, mercury and fine particle emissions, heat transfer) and operational concerns (fouling, slagging and corrosion) inherent in the retrofit of existing coal-fired boilers for oxy-coal combustion. Experimental work was conducted at Sandia National Laboratories’ Entrained Flow Reactor, the University of Utah Industrial Combustion Research Facility, and Brigham Young University. Process modeling and computational fluid dynamics (CFD) modeling was performed at REI. Successful completion of the project objectives resulted in the following key deliverables: 1) Multi-scale test data from 0.1 kW bench-scale, 100 kW and 200 kW laboratory-scale, and 1 MW semi-industrial scale combustors that describe differences in flame characteristics, fouling, slagging and corrosion for coal combustion under air-firing and oxygen-firing conditions, including sensitivity to oxy-burner design and flue gas recycle composition. 2) Validated mechanisms developed from test data that describe fouling, slagging, waterwall corrosion, heat transfer, char burnout and sooting under coal oxy-combustion conditions. The mechanisms were presented in a form suitable for inclusion in CFD models or process models. 3) Principles to guide design of pilot-scale and full-scale coal oxy-firing systems and flue gas recycle configurations, such that boiler operational impacts from oxy-combustion retrofits are minimized. 4

  18. Fouling detection in heat exchangers by Takagi-Sugeno observers

    International Nuclear Information System (INIS)

    The phenomenon of fouling in heat exchangers is currently an important topic. Indeed, the fouling is a costly issue that increases the energy loss (directly or indirectly through an over-sizing of the equipment), and therefore increases the water consumption. As a side effect, fouling increases CO2 consumption that leads to environmental consequences. Fouling can be detected either on local scale, using expensive and specific sensors or on global scale. Global estimation of fouling can be done by measuring the variation of the mass of the exchanger, or by estimating the efficiency of the exchanger through the transfer coefficient. These two methods require very restricting conditions: a powered exchanger to measure mass variation and a steady state exchanger to estimate the efficiency. The work introduced in this thesis deals with the development of non-linear observers that detect fouling early enough to start an efficient cleaning process. As a beginning, a finite element model of a counter current tubular exchanger was proposed. Then three approaches, based on non-linear Takagi-Sugeno observers, were suggested to detect early fouling in heat exchangers. First approach consisted in a set of observers that estimated the parameters of fouling effect through an interpolation method. The second approach proposed a polynomial Takagi-Sugeno observer, using the theory of sums of squares. Finally, a observer of Takagi-Sugeno type with unknown inputs was developed. As a conclusion, a comparison between those different methods was done. (author)

  19. Analysis of fouling mechanisms in anaerobic membrane bioreactors.

    Science.gov (United States)

    Charfi, Amine; Ben Amar, Nihel; Harmand, Jérôme

    2012-05-15

    In this paper, we investigate the fouling mechanisms responsible for MF and UF membrane flux decline in Anaerobic Membrane Bioreactors (AnMBR). We have used the fouling mechanism models proposed by Hermia (1982), namely pore constriction, cake formation, complete blocking and intermediate blocking. Based on an optimization approach and using experimental data extracted from the literature, we propose a systematic procedure for identifying the most likely fouling mechanism in play. Short-term as well as long-term experiments are considered and discussed. It was found that short-term experiments are usually characterized by two fouling phases during which the same fouling mechanism or two different mechanisms affect the process. In contrast, in long-term experiments involving cleaning cycles, membrane fouling appears to be better ascribed to one phase only. The impact of abiotic parameters on membrane fouling mechanisms is reviewed and discussed in the light of these results. Finally, it is shown that the mechanism most responsible for membrane fouling in an AnMBR is cake formation. This main result will be useful for the future development of simple integrated models for optimization and control. PMID:22397816

  20. Characterization of oxides on Bruce A NGS liner tubes and steam generator tubes

    International Nuclear Information System (INIS)

    Oxide deposits on end-fitting liner tubes and steam generator tubes from the Bruce A Nuclear Generating Station (NGS) were characterized in advance of the decontamination of the heat transport system (HTS) of Bruce Unit 2. Oxide loadings, and Co-60 surface activities and specific activities were determined for the oxides on inlet and outlet end-fitting liner tubes from Bruce Unit l, Bruce Unit 2 and Bruce Unit 4. Oxides on the inner surfaces of steam generator tubes from Bruce NGS Units 1 and 2 were also characterized. The consistency in the deposit characteristics on the inlet liner tubes and steam generator tubes from Bruce A, along with the absence of magnetite on the outlet liner tubes has led to the development of a model for iron transport in the HTS of pressurized heavy water reactors (PHWRs). The activity transport/fouling mechanism involves flow-accelerated corrosion of the outlet feeder pipes, followed by deposition of iron in the steam generators, along the inlet feeder pipes, on the inlet end fittings, on the inlet fuel bundles and on the inlet region of the pressure tube. The results of loop experiments using decontamination solutions indicated that the oxide was rapidly removed from inlet liner tubes. However, removal of the Cr-rich oxide from the outlet liner tubes was less efficient, requiring the Alkaline Permangante (AP) oxidizing pre-treatment that is typically used in light water reactors (LWRs). The steam generator tubes were effectively decontaminated

  1. Boiler-turbine life extension

    Energy Technology Data Exchange (ETDEWEB)

    Natzkov, S. [TOTEMA, Ltd., Sofia (Bulgaria); Nikolov, M. [CERB, Sofia (Bulgaria)

    1995-12-01

    The design life of the main power equipment-boilers and turbines is about 105 working hours. The possibilities for life extension are after normatively regulated control tests. The diagnostics and methodology for Boilers and Turbines Elements Remaining Life Assessment using up to date computer programs, destructive and nondestructive control of metal of key elements of units equipment, metal creep and low cycle fatigue calculations. As well as data for most common damages and some technical decisions for elements life extension are presented.

  2. CFD Simulation On CFBC Boiler

    Directory of Open Access Journals (Sweden)

    Amol S. Kinkar

    2015-02-01

    Full Text Available Abstract Heavy industrialization amp modernization of society demands in increasing of power cause to research amp develop new technology amp efficient utilization of existing power units. Variety of sources are available for power generation such as conventional sources like thermal hydro nuclear and renewable sources like wind tidal biomass geothermal amp solar. Out of these most common amp economical way for producing the power is by thermal power stations. Various industrial boilers plays an important role to complete the power generation cycle such as CFBC Circulating Fluidized Bed Combustion FBC Fluidized Bed Combustion AFBC Atmospheric Fluidized Bed Combustion Boiler CO Boiler RG amp WHR Boiler Waster heat recovery Boiler. This paper is intended to comprehensively give an account of knowledge related to refractory amp its failure in CFBC boiler with due effect of flue gas flow during operation on refractory by using latest technology of CAD Computer aided Design amp CAE Computer aided Engineering. By conceptual application of these technology the full scale model is able to analyze in regards the flow of flue gas amp bed material flow inside the CFBC loop via CFD Computational Fluid Dynamics software. The results obtained are helpful to understand the impact of gas amp particles on refractory in different areas amp also helped to choose suitable refractory material in different regions.

  3. Black liquor combustion validated recovery boiler modeling: Final year report. Volume 4 (Appendix IV)

    Energy Technology Data Exchange (ETDEWEB)

    Grace, T.M.; Frederick, W.J.; Salcudean, M.; Wessel, R.A.

    1998-08-01

    This project was initiated in October 1990, with the objective of developing and validating a new computer model of a recovery boiler furnace using a computational fluid dynamics (CFD) code specifically tailored to the requirements for solving recovery boiler flows, and using improved submodels for black liquor combustion based on continued laboratory fundamental studies. The key tasks to be accomplished were as follows: (1) Complete the development of enhanced furnace models that have the capability to accurately predict carryover, emissions behavior, dust concentrations, gas temperatures, and wall heat fluxes. (2) Validate the enhanced furnace models, so that users can have confidence in the predicted results. (3) Obtain fundamental information on aerosol formation, deposition, and hardening so as to develop the knowledge base needed to relate furnace model outputs to plugging and fouling in the convective sections of the boiler. (4) Facilitate the transfer of codes, black liquid submodels, and fundamental knowledge to the US kraft pulp industry. Volume 4 contains the following appendix sections: Radiative heat transfer properties for black liquor combustion -- Facilities and techniques and Spectral absorbance and emittance data; and Radiate heat transfer determination of the optical constants of ash samples from kraft recovery boilers -- Calculation procedure; Computation program; Density determination; Particle diameter determination; Optical constant data; and Uncertainty analysis.

  4. Fuel characterization requirements for cofiring biomass in coal-fired boilers

    International Nuclear Information System (INIS)

    The cofiring of biofuels with coal in existing boilers, or the cofiring of biofuels in combined cycle combustion turbine (CCCT) systems presents significant potential benefits to utilities, including reductions in SO2 and NOx emissions as a function of reducing the mass flow of sulfur and nitrogen to the boiler, reducing CO2 emissions from the combustion of fossil fuels; potentially reducing fuel costs both by the availability of wood residues and by the fact that biofuels are exempt from the proposed BTU tax; and providing support to industrial customers from the forest products industry. At the same time, cofiring requires careful attention to the characterization of the wood and coal, both singly and in combination. This paper reviews characterization requirements associated with cofiring biofuels and fossil fuels in boilers and CCCT installations with particular attention not only to such concerns as sulfur, nitrogen, moisture, and Btu content, but also to such issues as total ash content, base/acid ratio of the wood ash and the coal ash, alkali metal content in the wood ash and wood fuel (including converted fuels such as low Btu gas or pyrolytic oil), slagging and fouling indices, ash fusion temperature, and trace metal contents in the wood and coal. The importance of each parameter is reviewed, along with potential consequences of a failure to adequately characterize these parameters. The consequences of these parameters are reviewed with attention to firing biofuels with coal in pulverized coal (PC) and cyclone boilers, and firing biofuels with natural gas in CCCT installations

  5. Nickel- and iron-based HVOF thermal spray coatings for high temperature corrosion protection in biomass-fired power plant boilers

    OpenAIRE

    Oksa, Maria

    2015-01-01

    Biomass burning for production of electricity and heat has been increasing due to legislation in Europe. Growing awareness of environmental problems has led to strict restrictions on greenhouse emissions in the energy sector, and increased demand for higher use of renewable energy sources and carbon-neutral fuels, such as biomass. There are over 1000 biomass boilers in Europe, and the number is increasing. These plants often face serious problems due to high temperature corrosion. Fouling and...

  6. Black liquor combustion validated recovery boiler modeling, five-year report

    Energy Technology Data Exchange (ETDEWEB)

    Grace, T.M.; Frederick, W.J.; Salcudean, M.; Wessel, R.A.

    1996-08-01

    The objective of this project was to develop a new computer model of a recovery boiler furnace using a computational fluid dynamics (CFD) code specifically tailored to the requirements for solving recovery boiler flows, and using improved submodels for black liquor combustion based on continued laboratory fundamental studies. The project originated in October 1990 and was scheduled to run for four years. At that time, there was considerable emphasis on developing accurate predictions of the physical carryover of macroscopic particles of partially burnt black liquor and smelt droplets out of the furnace, since this was seen as the main cause of boiler plugging. This placed a major emphasis on gas flow patterns within the furnace and on the mass loss rates and swelling and shrinking rates of burning black liquor drops. As work proceeded on developing the recovery boiler furnace model, it became apparent that some recovery boilers encounter serious plugging problems even when physical carryover was minimal. After the original four-year period was completed, the project was extended to address this issue. The objective of the extended project was to improve the utility of the models by including the black liquor chemistry relevant to air emissions predictions and aerosol formation, and by developing the knowledge base and computational tools to relate furnace model outputs to fouling and plugging of the convective sections of the boilers. The work done to date includes CFD model development and validation, acquisition of information on black liquor combustion fundamentals and development of improved burning models, char bed model development, and model application and simplification.

  7. Organic Fouling of Graphene Oxide Membranes and Its Implications for Membrane Fouling Control in Engineered Osmosis.

    Science.gov (United States)

    Hu, Meng; Zheng, Sunxiang; Mi, Baoxia

    2016-01-19

    This study provides experimental evidence to mechanistically understand some contradicting effects of the characteristic properties of graphene oxide (GO), such as the high hydrophilicity, negative charge, strong adsorption capability, and large surface area, on the antifouling properties of GO membranes. Furthermore, this study demonstrates the effectiveness of forming a dense GO barrier layer on the back (i.e., porous) side of an asymmetric membrane for fouling control in pressure-retarded osmosis (PRO), an emerging engineered osmosis process whose advancement has been much hindered due to the severe irreversible fouling that occurs as foulants accumulate inside the porous membrane support. In the membrane fouling experiments, protein and alginate were used as model organic foulants. When operated in forward osmosis mode, the GO membrane exhibited fouling performance comparable with that of a polyamide (PA) membrane. Analysis of the membrane adsorption capacity showed that, likely due to the presence of hydrophobic regions in the GO basal plane, the GO membrane has an affinity toward organic foulants 4 to 5 times higher than the PA membrane. Such a high adsorption capacity along with a large surface area, however, did not noticeably aggravate the fouling problem. Our explanation for this phenomenon is that organic foulants are adsorbed mainly on the basal plane of GO nanosheets, and water enters the GO membrane primarily around the oxidized edges of GO, making foulant adsorption not create much hindrance to water flux. When operated in PRO mode, the GO membrane exhibited much better antifouling performance than the PA membrane. This is because unlike the PA membrane for which foulants can be easily trapped inside the porous support and hence cause severe irreversible fouling, the GO membrane allows the foulants to accumulate primarily on its surface due to the sealing effect of the GO layer assembled on the porous side of the asymmetric membrane support. Results

  8. Heat transfer characteristics of air cross-flow for in-line arrangement of spirally corrugated tube and smooth tube bundles

    Institute of Scientific and Technical Information of China (English)

    LU Guo-dong; ZHOU Qiang-tai; TIAN Mao-cheng; CHENG Lin; YU Xiao-li

    2005-01-01

    An experimental study on heat transfer and resistance coefficients of linearly arranged smooth and spirally corrugated tube bundles in cross-flow was performed. The heat transfer and resistance coefficients are presented in this paper with transverse and longitudinal tube-pitch and tube geometries taken into account. The experiment's results can provide technical guidelines for application to horizontal air preheater with arranged in-line spirally corrugated tube bundles, especially to the air preheater for CFBCBs (Circulating Fluidized Bed Combustion Boilers).

  9. KINERJA ECONOMIZER PADA BOILER

    Directory of Open Access Journals (Sweden)

    Muhammad Sjahid Akbar

    2009-01-01

    Full Text Available This paper employed the dual response approach for case of Multivariate Robust Parameter Design (MRPD which is developed by Del Castillo and Miro Quesada. MRPD method can be applied for any design of experiment. The optimization in this method uses minimizing variance function with restriction on mean function. In this paper, MRPD is applied to the case of optimization of heat transfer efectivity and operational cost at economizer. Those two responses are optimized by setting the level of control factors; diametre of tube hole, transversal spacing, and fin nearness. Temperature of feedwater is hold as a noise factor. Optimization is calculated by fmincon in MATLAB 7.0. The optimal condition for heat tranfer efectivity is 77.17% and operational cost is 30.58 kW. The optimal condition is attained at diametre of tube hole 1.5 inch, transversal spacing 3.5 inch, and fin density 3 fin/inch. Abstract in Bahasa Indonesia: Penelitian ini menggunakan metode pendekatan dual response terhadap kasus Multivariate Robust Parameter Design (MRPD yang dikembangkan oleh Del Castillo dan Miro Quesada. Metode MRPD tidak mensyaratkan jenis rancangan percobaan yang dapat digunakan dalam proses optimasi, yang dilakukan dengan meminimalkan fungsi varians terhadap kendala fungsi rerata. Pada penelitian ini, metode MRPD diterapkan untuk kasus pencarian nilai optimal respon yaitu efektifitas perpindahan panas dan biaya operasi pada economizer. Optimasi kedua respon dilakukan dengan cara mengoptimalkan level faktor kontrol diameter luar tubing, transversal spacing, dan kerapatan fin. Temperatur feedwater berlaku sebagai faktor noise. Optimasi dilakukan dengan bantuan fmincon pada MATLAB 7.0 yang menghasilkan kondisi optimum untuk efektifitas perpindahan panas sebesar 77,17% dan biaya operasi sebesar 30,58 kW. Kondisi tersebut dicapai pada saat level diameter luar tubing sebesar 1,5 inci, transversal spacing sebesar 3,5 inci, dan kerapatan fin sebesar 3 fin/inci. Kata kunci

  10. Reason Analysis on Bursting Tube of High Temperature Boiler Tube of T92 Steel in Ultra Supercritical Unit%超超临界机组T92钢高温受热面管爆管原因分析

    Institute of Scientific and Technical Information of China (English)

    赵彦芬; 张路; 刘艳; 许万军

    2012-01-01

    The platen superheater tube failures of T92 steel has bursted in a ultra supercritical power plants. The bursting reason was analyzed by means of macroscopical inspection, chemical composition analysis, hardness testing, tensile strength testing, metallographie examination and so on. Results showed that the microstructure of the tube which didn't maintenance the typical lath martensite, the phase transformation at Ac~ ~Aca after short- term overheated. The strength decreased rapid distinctly, therefore the strength was not enough to endure the stress, finally the tube bursted. On the other hand, the relationship between the different microstructure and mechanical property was achieved by test in order to supervise for metal in thermal power plants for long term operation.%某电厂的后屏过热器T92钢管段发生爆管。通过宏观检验、化学成分分析、硬度检验、拉伸性能测试、金相检验以及相关计算分析了爆管的原因。结果表明:管段发生短时过热后,其显微组织为Acl-Ac3相变产物,失去了原典型的回火板条马氏体组织特征,材料强度大幅度降低,从而使得强度不足以抵抗管子的使用应力而发生爆管。另外,通过检验获得了不同状态下的组织与性能的对应关系,有利于长期运行中的金属监督检验。

  11. INDUSTRIAL BOILER RETROFIT FOR NOX CONTROL: COMBINED SELECTIVE NONCATALYTIC REDUCTION AND SELECTIVE CATALYTIC REDUCTION

    Science.gov (United States)

    The paper describes retrofitting and testing a 590 kW (2 MBtu/hr), oil-fired, three-pass, fire-tube package boiler with a combined selective noncatalytic reduction (SNCR) and selective catalytic reduction (SCR) system. The system demonstrated 85% nitrogen oxides (NOx) reduction w...

  12. Fouling mechanisms in a laboratory-scale UV disinfection system.

    Science.gov (United States)

    Nessim, Yoel; Gehr, Ronald

    2006-11-01

    The fouling of quartz sleeves surrounding UV disinfection lamps is a perennial problem affecting both drinking water and wastewater applications. The mechanisms of fouling are not fully understood, but factors promoting fouling are believed to include heat, high hardness and/or high iron concentrations, and hydrodynamic forces. The role of UV radiation itself is unclear. The goal of this paper is to attempt to isolate the fouling mechanisms and to provide key information about those induced by UV radiation, using a unique laboratory-scale continuous-flow UV reactor. Its design allowed for irradiated and nonirradiated zones and control of both temperature and UV intensity at the fouling surface. Synthetic wastewater samples were tested with two levels of calcium, iron, phosphorus, and biochemical oxygen demand (as beef broth), and constant levels of magnesium and nitrogen to assess the effects of the four key variables. Average UV fluence before fouling exceeded 35 mJ/cm2, based on collimated beam tests. Foulant accumulation was monitored by UV intensity measurements and by mass and composition of foulant collected after an average of 56 hours of continuous operation. Tests showed that relative UV intensity dropped by as much as 100% when iron was present. Detailed results were assessed and yielded support for the following three UV-induced fouling mechanisms: (a) precipitation of ferric hydroxide [Fe(OH)3], (b) release of calcium from calcium-organics complexes followed by precipitation of iron-organics complexes, and (c) calcium carbonate precipitation. Other fouling mechanisms, such as sedimentation of preformed particles and sorption of calcium onto preformed colloids of Fe(OH)3, occurred outside the zone of UV radiation. Hence, these could be confused with concurrent UV-induced mechanisms in full-scale reactors. Iron and/or calcium undoubtedly created the most favorable conditions for fouling to occur; in the absence of both, fouling would be unlikely. The

  13. The fouling in the tubular heat exchanger of Algiers refinery

    Science.gov (United States)

    Harche, Rima; Mouheb, Abdelkader; Absi, Rafik

    2016-05-01

    Crude oil fouling in refinery preheat exchangers is a chronic operational problem that compromises energy recovery in these systems. Progress is hindered by the lack of quantitative knowledge of the dynamic effects of fouling on heat exchanger transfer and pressure drops. In subject of this work is an experimental determination of the thermal fouling resistance in the tubular heat exchanger of the crude oil preheats trains installed in an Algiers refinery. By measuring the inlet and outlet temperatures and mass flows of the two fluids, the overall heat transfer coefficient has been determined. Determining the overall heat transfer coefficient for the heat exchanger with clean and fouled surfaces, the fouling resistance was calculated. The results obtained from the two cells of exchangers studies, showed that the fouling resistance increased with time presented an exponential evolution in agreement with the model suggested by Kern and Seaton, with the existence of fluctuation caused by the instability of the flow rate and the impact between the particles. The bad cleaning of the heat exchangers involved the absence of the induction period and caused consequently, high values of the fouling resistance in a relatively short period of time.

  14. Fouling-resistant polymer brush coatings

    KAUST Repository

    Thérien-Aubin, Héloïse

    2011-11-01

    A major problem to be addressed with thin composite films used in processes such as coatings or water purification is the biofouling of the surface. To address this problem in a model system, functionalized polyaramide membranes containing an atom transfer radical polymerization (ATRP) initiator were synthesized as a versatile approach to easily modify the surface properties of the polyaramide. Poly(methacrylic acid) brushes were grown using surface initiated ATRP followed by the functionalization of the poly(methacrylic acid) brushes with different side-chains chosen to reduce adhesion between the membrane and foulant. The relation between membrane fouling and the physicochemical properties of the surface was investigated in detail. © 2011 Elsevier Ltd. All rights reserved.

  15. Development of Empirical Correlation to Calculate Pool Boiling Heat Transfer of Tandem Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Myeong-Gie [Andong National University, Andong (Korea, Republic of)

    2015-10-15

    The heat exchanging tubes are in vertical alignment. For the cases, the upper tube is affected by the lower tube. Since heat transfer is closely related to the conditions of tube surface, bundle geometry, and liquid, lots of studies have been carried out for the several decades to investigate the combined effects of those factors on pool boiling heat transfer. One of the most important parameters in the analysis of a tube array is the pitch ( P ) between tubes. Many researchers have been investigated its effect on heat transfer enhancement for the tube bundles and the tandem tubes. The effect of a tube array on heat transfer enhancement was also studied for application to the flooded evaporators. Cornwell and Schuller studied the sliding bubbles by high speed photography to account the enhancement of heat transfer observed at the upper tubes of a bundle. The study by Memory et al. shows the effects of the enhanced surface and oil adds to the heat transfer of tube bundles. They identified that, for the structured and porous bundles, oil addition leads to a steady decrease in performance. The flow boiling of n-pentane across a horizontal tube bundle was investigated experimentally by Roser et al. They identified that convective evaporation played a significant part of the total heat transfer. The fouling of the tube bundle under pool boiling was also studied by Malayeri et al. They identified that the mechanisms of fouling on the middle and top heater substantially differ from those at the bottom heater.

  16. Application of the Critical Heat Flux Look-Up Table to Large Diameter Tubes

    Directory of Open Access Journals (Sweden)

    M. El Nakla

    2013-01-01

    Full Text Available The critical heat flux look-up table was applied to a large diameter tube, namely 67 mm inside diameter tube, to predict the occurrence of the phenomenon for both vertical and horizontal uniformly heated tubes. Water was considered as coolant. For the vertical tube, a diameter correction factor was directly applied to the 1995 critical heat flux look-up table. To predict the occurrence of critical heat flux in horizontal tube, an extra correction factor to account for flow stratification was applied. Both derived tables were used to predict the effect of high heat flux and tube blockage on critical heat flux occurrence in boiler tubes. Moreover, the horizontal tube look-up table was used to predict the safety limits of the operation of boiler for 50% allowable heat flux.

  17. New controls spark boiler efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Engels, T. (Monsanto, University Park, IL (United States))

    1993-09-01

    Monsanto's NutraSweet plant in University Park, IL, produces aspartame, the patented NutraSweet artificial sweetener product. Until recently, boiler control was managed by a '60s-era Fireye jackshaft system in which air and natural gas were mechanically linked with an offset to compensate for oxygen trim. The interlocking devices on the Fireye system were becoming obsolete, and the boiler needed a new front end retrofitted for low emissions. In order to improve boiler control efficiency, we decided to modernize and automate the entire boiler control system. We replaced the original jackshaft system, and installed a Gordon-Piet burner system, including gas valves, air dampers, blowers, and burner. The upgrade challenges included developing a control strategy and selecting and implementing a process control system. Since our plant has standardized on the PROVOX process management information system from Fisher Controls (now Fisher-Rosemount Systems) to support most of our process, it was a natural and logical choice for boiler controls as well. 2 figs.

  18. 10 CFR 431.82 - Definitions concerning commercial packaged boilers.

    Science.gov (United States)

    2010-01-01

    ... pressure boiler means a packaged boiler that is: (1) A steam boiler designed to operate at a steam pressure... steam boiler designed to operate at or below a steam pressure of 15 psig; or (2) A hot water boiler... 10 Energy 3 2010-01-01 2010-01-01 false Definitions concerning commercial packaged boilers....

  19. Heat mass transfer model of fouling process of calcium carbonate on heat transfer surface

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A new heat mass transfer model was developed to predict the fouling process of calcium carbonate on heat transfer surface. The model took into account not only the crystallization fouling but also the particle fouling which was formed on the heat transfer surface by the suspension particles of calcium carbonate in the su- persaturated solution. Based on experimental results of the fouling process, the deposition and removal rates of the mixing fouling were expressed. Furthermore, the coupling effect of temperature with the fouling process was considered in the physics model. As a result the fouling resistance varying with time was obtained to describe the fouling process and the prediction was compared with experimental data under same conditions. The results showed that the present model could give a good prediction of fouling process, and the deviation was less than 15% of the experimental data in most cases. The new model is credible to predict the fouling process.

  20. PREDICTION OF OXIDE SCALE EXFOLIATION IN STEAM TUBES

    Energy Technology Data Exchange (ETDEWEB)

    Sabau, Adrian S [ORNL; Wright, Ian G [ORNL

    2010-01-01

    Numerical simulation results are presented for the prediction of the likelihood of oxide scale exfoliation from superheater tubes. The scenarios considered involved alloys T22, TP347H, and TP347HFG subjected to a simplified operating cycle in a power plant generating supercritical steam. The states of stress and strain of the oxides grown in steam were based solely on modeling the various phenomena experienced by superheater tubes during boiler operation, current understanding of the oxidation behavior of each alloy in steam, and consideration of operating parameters such as heat flux, tube dimensions, and boiler duty cycle. Interpretation of the evolution of strain in these scales, and the approach to conditions where scale failure (hence exfoliation) is expected, makes use of the type of Exfoliation Diagrams that incorporate various cracking and exfoliation criteria appropriate for the system considered. In these diagrams, the strain accumulation with time in an oxide is represented by a strain trajectory derived from the net strain resulting from oxide growth, differences in coefficients of thermal expansion among the components, and relaxation due to creep. It was found that an oxide growing on a tube subjected to routine boiler load cycling conditions attained relatively low values of net strain, indicating that oxide failure would not be expected to occur during normal boiler operation. However, during a boiler shut-down event, strains sufficient to exceed the scale failure criteria were developed after times reasonably in accord with plant experience, with the scales on the ferritic steel failing in tension, and those on the austenitic steels in compression. The results presented illustrate that using this approach to track the state of strain in the oxide scale through all phases of boiler operation, including transitions from full-to-low load and shut-down events, offers the possibility of identifying the phase(s) of boiler operation during which oxide

  1. MODELLING, SIMULATING AND OPTIMIZING BOILERS

    DEFF Research Database (Denmark)

    Sørensen, K.; Condra, T.; Houbak, Niels

    2003-01-01

    model of the boiler has been developed and simulations carried out by means of the Matlab integration routines. The model is prepared as a dynamic model consisting of both ordinary differential equations and algebraic equations, together formulated as a Differential-Algebraic-Equation system. Being able...... to the internal pressure the consequence of the increased volume (i.e. water-/steam space) is an increased wall thickness in the pressure part of the boiler. The stresses introduced in the boiler pressure part as a result of the temperature gradients are proportional to the square of the wall thickness......, and the total stress level (i.e. stresses introduced due to internal pressure plus stresses introduced due to temperature gradients) must always be kept below the allowable stress level. In this way, the increased water-/steam space that should allow for better dynamic performance, in the end causes limited...

  2. NOx Control Options and Integration for US Coal Fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Mike Bockelie; Marc Cremer; Kevin Davis; Martin Denison; Adel Sarofim; Connie Senior; Hong-Shig Shim; Dave Swenson; Bob Hurt; Eric Suuberg; Eric Eddings; Kevin Whitty; Larry Baxter; Calvin Bartholomew; William Hecker

    2006-06-30

    in a pilot scale furnace and soot behavior predicted by the CFD model showed good agreement. Field and laboratory tests were performed for SCR catalysts used for coal and biomass co-firing applications. Fundamental laboratory studies were performed to better understand mechanisms involved with catalyst deactivation. Field tests with a slip stream reactor were used to create catalyst exposed to boiler flue gas for firing coal and for co-firing coal and biomass. The field data suggests the mechanisms leading to catalyst deactivation are, in order of importance, channel plugging, surface fouling, pore plugging and poisoning. Investigations were performed to better understand the mechanisms involved with catalyst regeneration through mechanical or chemical methods. A computer model was developed to predict NOx reduction across the catalyst in a SCR. Experiments were performed to investigate the fundamentals of ammonia/fly ash interactions with relevance to the operation of advanced NOx control technologies such as selective catalytic reduction. Measurements were performed for ammonia adsorption isotherms on commercial fly ash samples subjected to a variety of treatments and on the chemistry of dry and semi-dry ammonia removal processes. This work resulted in the first fundamental ammonia isotherms on carbon-containing fly ash samples. This work confirms industrial reports that aqueous solution chemistry takes place upon the introduction of even very small amounts of water, while the ash remains in a semi-dry state.

  3. A New Concept of Ultrafiltration Fouling Control: Backwashing with Low Ionic Strength Water

    OpenAIRE

    Li, S.

    2011-01-01

    Ultrafiltration (UF) is a proven technology in water treatment nowadays. However, fouling remains a major challenge in the operation of UF, especially in regard to colloidal NOM fouling. In general, a number of colloidal NOM fouling mechanisms may occur, such as adsorption, gel formation. Colloidal NOM fouling is influenced by multivalent cations, ionic strength and pH. In order to control membrane fouling, different pretreatments such as powder activated carbon adsorption, lime softening, io...

  4. Modeling of the buckstay system of membrane-walls in watertube boiler construction

    Directory of Open Access Journals (Sweden)

    Nagiar Hasan Mehdi

    2014-01-01

    Full Text Available Membrane walls are very important structural parts of water-tube boiler construction. Based on their specific geometry, one special type of finite element was defined to help model the global boiler construction. That is the element of reduced orthotropic plate with two thicknesses and two elasticity matrixes, for membrane and bending load separately. A global model of the boiler construction showed that the high value of stress is concentrated in plates of the buckstay system in boiler corners. Validation of the new finite element was done on the local model of the part of membrane wall and buckstay. A very precise model of tubes and flanges was compared to the model formed on the element of a reduced orthotropic plate. Pressure and thermal loads were discussed. Obtained results indicated that the defined finite element was quite favorable in the design and reconstruction of the boiler substructures such as a buckstay system. [Projekat Ministarstva nauke Republike Srbije, br. TR 35040 i br. TR 35011

  5. Superheater materials for waste incinerator boilers. Trials at the Hoegdalen plant

    International Nuclear Information System (INIS)

    In order to obtain an acceptable length of life for the superheaters in waste incinerated boilers a considerably lower steam temperature is used than when incinerating conventional fuel. In spite of this the life of the superheaters is unsatisfactory, with the occurrence of damage in some type of incinerator boilers after only a few years operation. The use of high alloyed material instead of conventional pressure vessel steels can increase the length of life and improve operational efficiency in existing incinerator boilers. Such tubes permit higher steam data for new plants. Cooled materials testing probes have been mounted in the flue gas duct close to the superheater in two boilers in the Hoegdalen plant, Stockholm. The materials temperatures have been maintained in the range 400-500 degrees C. Low metal losses have been obtained, in particular with Alloy 625, but also with Alloy 825 and Sandvik Sanicro 28. The attack on the tubes is corrosion, caused by the aggressive dust which is trapped in the superheaters. In these trials it has been shown that correct boiler design is very important, in conjunction with the choice of materials

  6. Superheater materials for waste incinerator boilers. Trials at the Hoegdalen plant

    Energy Technology Data Exchange (ETDEWEB)

    Haeggblom, E.

    1992-12-01

    In order to obtain an acceptable length of life for the superheaters in waste incinerated boilers a considerably lower steam temperature is used than when incinerating conventional fuel. In spite of this the life of the superheaters is unsatisfactory, with the occurrence of damage in some type of incinerator boilers after only a few years operation. The use of high alloyed material instead of conventional pressure vessel steels can increase the length of life and improve operational efficiency in existing incinerator boilers. Such tubes permit higher steam data for new plants. Cooled materials testing probes have been mounted in the flue gas duct close to the superheater in two boilers in the Hoegdalen plant, Stockholm. The materials temperatures have been maintained in the range 400-500 degrees C. Low metal losses have been obtained, in particular with Alloy 625, but also with Alloy 825 and Sandvik Sanicro 28. The attack on the tubes is corrosion, caused by the aggressive dust which is trapped in the superheaters. In these trials it has been shown that correct boiler design is very important, in conjunction with the choice of materials.

  7. Optimizing the integrated design of boilers - simulation

    DEFF Research Database (Denmark)

    Sørensen, Kim; Karstensen, Claus M. S.; Condra, Thomas Joseph;

    2004-01-01

    Boilers can be considered as consisting of three main components: (i) the pressure part, (ii) the burner and (iii) the control system. To be able to develop the boilers of the future (i.e. the boilers with the lowest emissions, the highest efciency, the best dynamic performance etc.) it is import...

  8. 29 CFR 1915.162 - Ship's boilers.

    Science.gov (United States)

    2010-07-01

    ... Ship's boilers. (a) Before work is performed in the fire, steam, or water spaces of a boiler where employees may be subject to injury from the direct escape of a high temperature medium such as steam, or... 29 Labor 7 2010-07-01 2010-07-01 false Ship's boilers. 1915.162 Section 1915.162 Labor...

  9. Dynamic simulation model for ultra supercritical 1 000 MW unit boilers%Dynamic simulation model for ultra supercritical 1000 MW unit boilers

    Institute of Scientific and Technical Information of China (English)

    XU Hui; XU Ershu

    2013-01-01

    On the basis of heat transfer characteristics of working fluid at different pressures inside the water wall tube and structure of the ultra supercritical 1 000 MW unit once through boiler in Jianbi Power Plant,the varying phase transformation point method was adopted to establish the moving-boundary dynamic simulation model of water wall in ultra supercritical once through boilers,especially the length variation of hot water section,evaporation section and superheat section against the load changing.On this basis,the real-time dynamic simulation model for ultra-supercritical 1 000 MW unit boiler in Jianbi Power Plant was built on the STAR-90 simulation platform.The dynamic and static characteristics test showed that,this model can simulate the unit's startup/shutdown process and some typical fault conditions accurately,and had good dynamic and static performance.

  10. High-Temperature Behavior of a NiCr-Coated T91 Boiler Steel in the Platen Superheater of Coal-Fired Boiler

    Science.gov (United States)

    Chatha, Sukhpal Singh; Sidhu, Hazoor S.; Sidhu, Buta S.

    2013-06-01

    Ni-20Cr coating was deposited on T91 boiler tube steel by high-velocity oxy-fuel (HVOF) process to enhance high-temperature oxidation resistance. High-temperature performance of bare, as well as HVOF-coated steel specimens was evaluated for 1500 h under in the platen superheater zone of coal-fired boiler, where the temperature was around 900 °C. Experiments were carried out for 15 cycles, each of 100-h duration followed by 1-h cooling at ambient temperature. The extent of degradation of the specimens was assessed by the thickness loss and depth of internal corrosion attack. Ni-20Cr-coated steel performed better than the uncoated steel in actual boiler environment. The improved degradation resistance of Ni-20Cr coating can be attributed to the presence of Cr2O3 in the top oxide scale and dense microstructure.

  11. Low excess air operations of oil boilers

    Energy Technology Data Exchange (ETDEWEB)

    Butcher, T.A.; Celebi, Y.; Litzke, Wai Lin [Brookhaven National Labs., Upton, NY (United States)

    1997-09-01

    To quantify the benefits which operation at very low excess air operation may have on heat exchanger fouling BNL has recently started a test project. The test allows simultaneous measurement of fouling rate, flue gas filterable soot, flue gas sulfuric acid content, and flue gas sulfur dioxide.

  12. Abundance of bacterial and diatom fouling on various surfaces

    Digital Repository Service at National Institute of Oceanography (India)

    PrabhaDevi

    Abundance of bacterial and diatom fouling on aluminium, fibreglass and stainless steel were studied from Dona Paula waters of the Zuari Estuary. Both these forms were reversibly attached in large numbers to surfaces during the initial 24 hr...

  13. Scaling and particulate fouling in membrane filtration systems

    NARCIS (Netherlands)

    Boerlage, S.F.E.

    2001-01-01

    Membrane filtration technologies have emerged as cost competitive and viable techniques in drinking and industrial water production. Despite advancements in membrane manufacturing and technology, membrane scaling and fouling remain major problems and may limit future growth in the industry. Scaling

  14. A sinister bias for calling fouls in soccer.

    Directory of Open Access Journals (Sweden)

    Alexander Kranjec

    Full Text Available Distinguishing between a fair and unfair tackle in soccer can be difficult. For referees, choosing to call a foul often requires a decision despite some level of ambiguity. We were interested in whether a well documented perceptual-motor bias associated with reading direction influenced foul judgments. Prior studies have shown that readers of left-to-right languages tend to think of prototypical events as unfolding concordantly, from left-to-right in space. It follows that events moving from right-to-left should be perceived as atypical and relatively debased. In an experiment using a go/no-go task and photographs taken from real games, participants made more foul calls for pictures depicting left-moving events compared to pictures depicting right-moving events. These data suggest that two referees watching the same play from distinct vantage points may be differentially predisposed to call a foul.

  15. Fouling Characteristics and Prevention Techniques for Membrane Bioreactor

    Institute of Scientific and Technical Information of China (English)

    LU Hua; WANG Zhi-qiang; YANG Jin-ying

    2005-01-01

    Membrane fouling is the main problem of membrane bioreactors (MBR), which seriously influences its wastewater treatment effect and running. The characteristics of microbiology and hydrodynamics concerning membrane fouling were investigated and the measure was put forward for optimum operation of MBR. The measure is that 1) the parameters of activated sludge concentration (X) and membrane flux should be lower than the critical values of X and membrane flux respectively, and 2) the activated sludge should be discharged periodically. The experimental results show that the combination backwashing of gas and permeated effluent is better than single gas backwashing or single permeated effluent backwashing. This technique can remove the cake layer deposited on the membrane surface, decrease the membrane fouling, and recover the membrane flux effectively. So it is effective for prevention of membrane fouling.

  16. Artificial structures influence fouling on habitat-forming kelps.

    Science.gov (United States)

    Marzinelli, Ezequiel M

    2012-01-01

    The addition of artificial structures along urbanised shorelines is a global phenomenon. Such modifications of habitats have important consequences to the abundance of fouling organisms on primary substrata, but the influence on fouling of habitat-formers living on these structures is poorly understood. Fouling of habitat-forming kelps Ecklonia radiata on pier-pilings was compared to that on rocky reefs at three locations in Sydney Harbour. Kelps on pilings supported different assemblages of bryozoans from those on reefs. The abundances of bryozoans on kelps, in particular of the non-indigenous species Membranipora membranacea, were significantly greater on pilings. Differences were consistent in time and space. This indicates that the addition of artificial structures also affects fouling on secondary biogenic substrata, altering biodiversity and potentially facilitating the introduction and dispersal of non-indigenous epibiota. Understanding the processes that cause these patterns is necessary to allow sensible predictions about ecological effects of built structures. PMID:22452393

  17. A Sinister Bias for Calling Fouls in Soccer

    Science.gov (United States)

    Kranjec, Alexander; Lehet, Matthew; Bromberger, Bianca; Chatterjee, Anjan

    2010-01-01

    Distinguishing between a fair and unfair tackle in soccer can be difficult. For referees, choosing to call a foul often requires a decision despite some level of ambiguity. We were interested in whether a well documented perceptual-motor bias associated with reading direction influenced foul judgments. Prior studies have shown that readers of left-to-right languages tend to think of prototypical events as unfolding concordantly, from left-to-right in space. It follows that events moving from right-to-left should be perceived as atypical and relatively debased. In an experiment using a go/no-go task and photographs taken from real games, participants made more foul calls for pictures depicting left-moving events compared to pictures depicting right-moving events. These data suggest that two referees watching the same play from distinct vantage points may be differentially predisposed to call a foul. PMID:20628648

  18. A sinister bias for calling fouls in soccer.

    Science.gov (United States)

    Kranjec, Alexander; Lehet, Matthew; Bromberger, Bianca; Chatterjee, Anjan

    2010-01-01

    Distinguishing between a fair and unfair tackle in soccer can be difficult. For referees, choosing to call a foul often requires a decision despite some level of ambiguity. We were interested in whether a well documented perceptual-motor bias associated with reading direction influenced foul judgments. Prior studies have shown that readers of left-to-right languages tend to think of prototypical events as unfolding concordantly, from left-to-right in space. It follows that events moving from right-to-left should be perceived as atypical and relatively debased. In an experiment using a go/no-go task and photographs taken from real games, participants made more foul calls for pictures depicting left-moving events compared to pictures depicting right-moving events. These data suggest that two referees watching the same play from distinct vantage points may be differentially predisposed to call a foul. PMID:20628648

  19. Fouling in small hydro projects; Verschmutzung von Kleinwasserkraftwerken - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Abgottspon, A.; Staubli, T.

    2010-03-15

    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) takes a look at fouling problems encountered in small hydro installations. The report is based on ten interviews made with operators of small hydro power stations in Switzerland. A parallel project carried out in Germany is mentioned. A large variation in the degree of fouling in the various hydro power stations is noted. Sources such as leaves in autumn and algae are discussed, as are the various rinsing procedures used to clear the turbines of fouling. Power losses are discussed and measures that can be taken to prevent fouling are described. Measurements made at an installation in Freienstein, Switzerland, are presented and discussed. The report is completed with an appendix containing calculations, details on the Freienstein power plant and the results of interviews made with the ten hydro power installations examined.

  20. Hydrodynamic analysis and calculation of metal temperature distribution in spiral water wall of ultra supercritical tower boiler

    Science.gov (United States)

    Shen, Chengwu; Yang, Dong; Yao, Danhua; Zhu, Yufeng; Xu, Xueyuan

    2013-07-01

    In this paper, the spiral water wall system of a 1000MW ultra supercritical tower boiler is simplified as a network system, consisting of circuits, pressure grids and connecting tubes. The establishment of the mathematical model for calculating the mass flux distribution and metal temperature in water wall is based on the mass, momentum and energy conservation equations. The water wall flow distribution and temperature profile of the boiler were computed. The result shows that the differences of outlet temperature and mass flux are small in spiral tube water wall at BMCR, 75%BMCR load and 40%BMCR load. The metal temperatures are all in the allowable ranger.

  1. Ultrafiltration Membrane Fouling and the Effect of Ion Exchange Resins

    KAUST Repository

    Jamaly, Sanaa

    2011-12-01

    Membrane fouling is a challenging process for the ultrafiltration membrane during wastewater treatment. This research paper determines the organic character of foulants of different kinds of wastewater before and after adding some ion exchange resins. Two advanced organic characterization methods are compared in terms of concentration of dissolved organic carbons: The liquid chromatography with organic carbon (LC-OCD) and Shimadzu total organic carbon (TOC). In this study, two secondary wastewater effluents were treated using ultrafiltration membrane. To reduce fouling, pretreatment using some adsorbents were used in the study. Six ion exchange resins out of twenty were chosen to compare the effect of adsorbents on fouling membrane. Based on the percent of dissolved organic carbon’s removal, three adsorbents were determined to be the most efficient (DOWEX Marathon 11 anion exchange resin, DOWEX Optipore SD2 polymeric adsorbent, and DOWEX PSR2 anion exchange), and three other ones were determined to the least efficient (DOWEX Marathon A2 anion exchange resin, DOWEX SAR anion exchange resin, and DOWEX Optipore L493 polymeric adsorbent). Organic characterization for feed, permeate, and backwash samples were tested using LC-OCD and TOC to better understand the characteristics of foulants to prevent ultrafiltration membrane fouling. The results suggested that the polymeric ion exchange resin, DOWEX SD2, reduced fouling potential for both treated wastewaters. All the six ion exchange resins removed more humic fraction than other organic fractions in different percent, so this fraction is not the main for cause for UF membrane fouling. The fouling of colloids was tested before and after adding calcium. There is a severe fouling after adding Ca2+ to effluent colloids.

  2. A Sinister Bias for Calling Fouls in Soccer

    OpenAIRE

    Alexander Kranjec; Matthew Lehet; Bianca Bromberger; Anjan Chatterjee

    2010-01-01

    Distinguishing between a fair and unfair tackle in soccer can be difficult. For referees, choosing to call a foul often requires a decision despite some level of ambiguity. We were interested in whether a well documented perceptual-motor bias associated with reading direction influenced foul judgments. Prior studies have shown that readers of left-to-right languages tend to think of prototypical events as unfolding concordantly, from left-to-right in space. It follows that events moving from ...

  3. Kinetic study of seawater reverse osmosis membrane fouling

    KAUST Repository

    Khan, Muhammad

    2013-10-01

    Reverse osmosis (RO) membrane fouling is not a static state but a dynamic phenomenon. The investigation of fouling kinetics and dynamics of change in the composition of the foulant mass is essential to elucidate the mechanism of fouling and foulant-foulant interactions. The aim of this work was to study at a lab scale the fouling process with an emphasis on the changes in the relative composition of foulant material as a function of operating time. Fouled membrane samples were collected at 8 h, and 1, 2, and 4 weeks on a lab-scale RO unit operated in recirculation mode. Foulant characterization was performed by CLSM, AFM, ATR-FTIR, pyrolysis GC-MS, and ICP-MS techniques. Moreover, measurement of active biomass and analysis of microbial diversity were performed by ATP analysis and DNA extraction, followed by pyro-sequencing, respectively. A progressive increase in the abundance of almost all the foulant species was observed, but their relative proportion changed over the age of the fouling layer. Microbial population in all the membrane samples was dominated by specific groups/species belonging to Proteobacteria and Actinobacteria phyla; however, similar to abiotic foulant, their relative abundance also changed with the biofilm age. © 2013 American Chemical Society.

  4. Superheater Tube Flat Wall Stationary Temperature Field

    Directory of Open Access Journals (Sweden)

    Parpiev A.T.

    2016-01-01

    Full Text Available The BKZ-220-100-9 steam generator platen superheater tube flat wall stationary temperature fields analysis have been made. The six steel grades, using in boiler fabrication, namely, St. 10, St. 20, 12H1MF, 15HM, 1H18N9T and 12H18N12T, have been used. The temperature curves calculation has been made by using outer and inner surface heat-transfer coefficients nine different combinations.

  5. Integrating multi-objective optimization with computational fluid dynamics to optimize boiler combustion process of a coal fired power plant

    International Nuclear Information System (INIS)

    Highlights: • A coal fired power plant boiler combustion process model based on real data. • We propose multi-objective optimization with CFD to optimize boiler combustion. • The proposed method uses software CORBA C++ and ANSYS Fluent 14.5 with AI. • It optimizes heat flux transfers and maintains temperature to avoid ash melt. - Abstract: The dominant role of electricity generation and environment consideration have placed strong requirements on coal fired power plants, requiring them to improve boiler combustion efficiency and decrease carbon emission. Although neural network based optimization strategies are often applied to improve the coal fired power plant boiler efficiency, they are limited by some combustion related problems such as slagging. Slagging can seriously influence heat transfer rate and decrease the boiler efficiency. In addition, it is difficult to measure slag build-up. The lack of measurement for slagging can restrict conventional neural network based coal fired boiler optimization, because no data can be used to train the neural network. This paper proposes a novel method of integrating non-dominated sorting genetic algorithm (NSGA II) based multi-objective optimization with computational fluid dynamics (CFD) to decrease or even avoid slagging inside a coal fired boiler furnace and improve boiler combustion efficiency. Compared with conventional neural network based boiler optimization methods, the method developed in the work can control and optimize the fields of flue gas properties such as temperature field inside a boiler by adjusting the temperature and velocity of primary and secondary air in coal fired power plant boiler control systems. The temperature in the vicinity of water wall tubes of a boiler can be maintained within the ash melting temperature limit. The incoming ash particles cannot melt and bond to surface of heat transfer equipment of a boiler. So the trend of slagging inside furnace is controlled. Furthermore, the

  6. Test results from a full-scale sodium reflux pool-boiler solar receiver

    Science.gov (United States)

    Moreno, J. B.; Andraka, C. E.; Diver, R. B.; Ginn, W. C.; Dudley, V.; Rawlinson, K. S.

    1990-01-01

    A sodium reflux pool-boiler solar receiver has been tested on a nominal 75 kW sub t parabolic-dish concentrator. The purpose was to demonstrate the feasibility of reflux-receiver technology for application to Stirling-engine dish-electric systems. In this application, pool boilers (and more generally liquid-metal reflux receivers) have a number of advantages over directly-illuminated tube receivers. The advantages, to be discussed, include more uniform temperature, which results in longer lifetime and higher temperature available to the engine.

  7. Characterization and Quantification of Deposits Buildup and Removal in Biomass Suspension-Fired Boilers

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming;

    2010-01-01

    uptake reduction, fly ash and deposit characteristics, and deposit removal by using an advanced online deposit probe in a suspension­fired boiler using wood and straw pellets as fuel. The influence of fuel type and probe exposure time on the ash deposition rate, the heat uptake, the fly ash and deposit...... small in the tube bank region (flue gas temperature, 550­605 oC) during pure wood­firing. It was found that during suspension­firing of pure straw at low boiler load, the overall weight uptake is comparable with grate­firing, even though the amount of fly ash generated was significantly higher during...

  8. Fouling and slagging problems at recovered wood fuel combustion; Orsaker till askrelaterade driftproblem vid eldning av returtraeflis

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Christer; Hoegberg, Jan [Vattenfall Utveckling AB, Stockholm (Sweden)

    2001-03-01

    CHP-plants that use a large portion of sorted wood waste fuel can face ash-related problems. By analysing the circumstances about these problems, the goal is to find causes for the problems and measures that can be taken. This knowledge can then be utilised in plants where it is desired to increase the portion of sorted wood waste fuel. For the measurements, a deposit probe is a good tool to use since the result is independent of many boiler-specific factors. Compared with forest residues, sorted wood waste causes a more problematic ash. The risk of troublesome fouling and corrosion seems to increase with increased admixture of sorted wood waste fuel. Plugging of the grate is associated with melts that are formed from metallic contamination in the fuel. These melts obstruct the air holes. The melts that have been seen during the project have had a content of aluminium, brass and zinc. In order to solve these problems, the construction and cooling of the grate and quality assurance of the fuel are important aspects. One problem that was found in all of the studied boilers (grates as well as fluidized beds) is growth of fouling on surfaces for heat transfer. Measurements with deposit probe show that the initial growth rate on superheaters are approximately 3 - 5 times higher when sorted wood waste is used than if forest residues is used. Even if this growth rate can not be extrapolated to a complete operating season, the relative difference between the fuels remains. The extent of the problem depends on the dimensioning of the boiler. The fouling tends to have a light outer layer that can be disadvantageous for the absorption of heat radiation. Haendeloe P11 needs for example to be stopped for cleaning with an interval of 2 - 3 months because of lost heat absorption in the furnace and the convection path. The most obvious ash related problem that was found in Haendeloe P11 when 100 % sorted wood waste fuel was used was corrosion on the walls of the lower parts of the

  9. Superhydrophilic Thin-Film Composite Forward Osmosis Membranes for Organic Fouling Control: Fouling Behavior and Antifouling Mechanisms

    KAUST Repository

    Tiraferri, Alberto

    2012-10-16

    This study investigates the fouling behavior and fouling resistance of superhydrophilic thin-film composite forward osmosis membranes functionalized with surface-tailored nanoparticles. Fouling experiments in both forward osmosis and reverse osmosis modes are performed with three model organic foulants: alginate, bovine serum albumin, and Suwannee river natural organic matter. A solution comprising monovalent and divalent salts is employed to simulate the solution chemistry of typical wastewater effluents. Reduced fouling is consistently observed for the superhydrophilic membranes compared to control thin-film composite polyamide membranes, in both reverse and forward osmosis modes. The fouling resistance and cleaning efficiency of the functionalized membranes is particularly outstanding in forward osmosis mode where the driving force for water flux is an osmotic pressure difference. To understand the mechanism of fouling, the intermolecular interactions between the foulants and the membrane surface are analyzed by direct force measurement using atomic force microscopy. Lower adhesion forces are observed for the superhydrophilic membranes compared to the control thin-film composite polyamide membranes. The magnitude and distribution of adhesion forces for the different membrane surfaces suggest that the antifouling properties of the superhydrophilic membranes originate from the barrier provided by the tightly bound hydration layer at their surface, as well as from the neutralization of the native carboxyl groups of thin-film composite polyamide membranes. © 2012 American Chemical Society.

  10. Fouling of a spiral-wound reverse osmosis membrane processing swine wastewater: effect of cleaning procedure on fouling resistance.

    Science.gov (United States)

    Camilleri-Rumbau, M S; Masse, L; Dubreuil, J; Mondor, M; Christensen, K V; Norddahl, B

    2016-07-01

    Swine manure is a valuable source of nitrogen, phosphorus and potassium. After solid-liquid separation, the resulting swine wastewater can be concentrated by reverse osmosis (RO) to produce a nitrogen-potassium rich fertilizer. However, swine wastewater has a high fouling potential and an efficient cleaning strategy is required. In this study, a semi-commercial farm scale RO spiral-wound membrane unit was fouled while processing larger volumes of swine wastewater during realistic cyclic operations over a 9-week period. Membrane cleaning was performed daily. Three different cleaning solutions, containing SDS, SDS+EDTA and NaOH were compared. About 99% of the fouling resistance could be removed by rinsing the membrane with water. Flux recoveries (FRs) above 98% were achieved for all the three cleaning solutions after cleaning. No significant differences in FR were found between the cleaning solutions. The NaOH solution thus is a good economical option for cleaning RO spiral-wound membranes fouled with swine wastewater. Soaking the membrane for 3 days in permeate water at the end of each week further improved the FR. Furthermore, a fouling resistance model for predicting the fouling rate, permeate flux decay and cleaning cycle periods based on processing time and swine wastewater conductivity was developed. PMID:26698296

  11. Superhydrophilic thin-film composite forward osmosis membranes for organic fouling control: fouling behavior and antifouling mechanisms.

    Science.gov (United States)

    Tiraferri, Alberto; Kang, Yan; Giannelis, Emmanuel P; Elimelech, Menachem

    2012-10-16

    This study investigates the fouling behavior and fouling resistance of superhydrophilic thin-film composite forward osmosis membranes functionalized with surface-tailored nanoparticles. Fouling experiments in both forward osmosis and reverse osmosis modes are performed with three model organic foulants: alginate, bovine serum albumin, and Suwannee river natural organic matter. A solution comprising monovalent and divalent salts is employed to simulate the solution chemistry of typical wastewater effluents. Reduced fouling is consistently observed for the superhydrophilic membranes compared to control thin-film composite polyamide membranes, in both reverse and forward osmosis modes. The fouling resistance and cleaning efficiency of the functionalized membranes is particularly outstanding in forward osmosis mode where the driving force for water flux is an osmotic pressure difference. To understand the mechanism of fouling, the intermolecular interactions between the foulants and the membrane surface are analyzed by direct force measurement using atomic force microscopy. Lower adhesion forces are observed for the superhydrophilic membranes compared to the control thin-film composite polyamide membranes. The magnitude and distribution of adhesion forces for the different membrane surfaces suggest that the antifouling properties of the superhydrophilic membranes originate from the barrier provided by the tightly bound hydration layer at their surface, as well as from the neutralization of the native carboxyl groups of thin-film composite polyamide membranes. PMID:23002900

  12. Application of membrane type economizer in 220 t/h boiler%膜式省煤器在220 t/h锅炉中的应用

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      膜式省煤器在电厂锅炉得到了普遍应用,文章根据其在220 t/h锅炉上的实际应用情况,对膜式省煤器和光管式省煤器的优劣进行比较,并得出具有实际意义的结论,为今后的锅炉对流受热面的改造提供指导。%Compared the membrane economizer with properties of bare tube economizer,the former has more advantages.For 220t/h boiler tube economizer's severe wear and frequent tube explosion,the No. 1 and No. 2 boiler of low temperature economizer were trans-formed. In fact,it not only improves the boiler efficiency but also ensures no tube explosion.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  14. Application of an empirical model in CFD simulations to predict the local high temperature corrosion potential in biomass fired boilers

    International Nuclear Information System (INIS)

    To gain reliable data for the development of an empirical model for the prediction of the local high temperature corrosion potential in biomass fired boilers, online corrosion probe measurements have been carried out. The measurements have been performed in a specially designed fixed bed/drop tube reactor in order to simulate a superheater boiler tube under well-controlled conditions. The investigated boiler steel 13CrMo4-5 is commonly used as steel for superheater tube bundles in biomass fired boilers. Within the test runs the flue gas temperature at the corrosion probe has been varied between 625 °C and 880 °C, while the steel temperature has been varied between 450 °C and 550 °C to simulate typical current and future live steam temperatures of biomass fired steam boilers. To investigate the dependence on the flue gas velocity, variations from 2 m·s−1 to 8 m·s−1 have been considered. The empirical model developed fits the measured data sufficiently well. Therefore, the model has been applied within a Computational Fluid Dynamics (CFD) simulation of flue gas flow and heat transfer to estimate the local corrosion potential of a wood chips fired 38 MW steam boiler. Additionally to the actual state analysis two further simulations have been carried out to investigate the influence of enhanced steam temperatures and a change of the flow direction of the final superheater tube bundle from parallel to counter-flow on the local corrosion potential. - Highlights: • Online corrosion probe measurements in a fixed bed/drop tube reactor. • Development of an empirical corrosion model. • Application of the model in a CFD simulation of flow and heat transfer. • Variation of boundary conditions and their effects on the corrosion potential

  15. KARAKTERISTIK INTERAKSI MEMBRAN-FOULANT DAN FOULANT-FOULANT SEBAGAI DASAR PENGENDALIAN FOULING

    Directory of Open Access Journals (Sweden)

    Heru Susanto

    2012-05-01

    Full Text Available THE CHARACTERISTICS OF MEMBRANE-FOULANT AND FOULANT-FOULANT INTERACTIONS AS THE BASIS FOR CONTROL OF FOULING. Industrial membrane applications for solid liquid and liquid-liquid filtration are limited by fouling and concentration polarization. Because fouling significantly reduces the membrane performance and often changes the membrane selectivity, efforts to overcome the fouling problem are very important from practical applications point of view. This paper presents the basic knowledge required to control fouling and recent development in fouling control including the method developed by the author. Control of fouling can be done by (i commercial membrane modification (post modification by photo-graft polymerization, (ii modification by polymer blending during membrane manufacturing and (iii integration of a pretreatment into membrane processes. The results showed that all the developed methods can significantly reduce the resulting fouling; however, none of the method could totally remove the occurring fouling. The understanding of the membrane-foulant and foulant-foulant interactions is the key to success in control of fouling.Aplikasi teknologi membran untuk pemisahan padat cair di  berbagai industri dibatasi oleh peristiwa fouling yang menyebabkan penurunan laju produk dan perubahan selektifitas membran. Oleh karena itu, pengendalian fouling merupakan upaya yang mutlak harus dilakukan. Makalah ini mempresentasikan pengetahuan dasar yang diperlukan untuk pengendalian fouling dan perkembangan terkini dalam pengendalian fouling termasuk hasil-hasil yang telah dikembangkan oleh penulis. Pengendalian fouling dilakukan dengan (i modifikasi membran komersial (post modification menggunakan metode photo-grafting, (ii modifikasi dengan pencampuran polimer selama proses pembuatan (polymer blend dan (iii integrasi unit perlakuan awal (pre-treatment dengan proses membran. Hasil penelitian menunjukkan bahwa kesemua metode yang dikembangkan dapat

  16. Natural organic matter fouling behaviors on superwetting nanofiltration membranes.

    Science.gov (United States)

    Shan, Linglong; Fan, Hongwei; Guo, Hongxia; Ji, Shulan; Zhang, Guojun

    2016-04-15

    Nanofiltration has been widely recognized as a promising technology for the removal of micro-molecular organic components from natural water. Natural organic matter (NOM), a very important precursor of disinfection by-products, is currently considered as the major cause of membrane fouling. It is necessary to develop a membrane with both high NOM rejection and anti-NOM fouling properties. In this study, both superhydrophilic and superhydrophobic nanofiltration membranes for NOM removal have been fabricated. The fouling behavior of NOM on superwetting nanofiltration membranes has been extensively investigated by using humic acid (HA) as the model foulant. The extended Derjaguin-Landau-Verwey-Overbeek approach and nanoindentor scratch tests suggested that the superhydrophilic membrane had the strongest repulsion force to HA due to the highest positive total interaction energy (ΔG(TOT)) value and the lowest critical load. Excitation emission matrix analyses of natural water also indicated that the superhydrophilic membrane showed resistance to fouling by hydrophobic substances and therefore high removal thereof. Conversely, the superhydrophobic membrane showed resistance to fouling by hydrophilic substances and therefore high removal capacity. Long-term operation suggested that the superhydrophilic membrane had high stability due to its anti-NOM fouling capacity. Based on the different anti-fouling properties of the studied superwetting membranes, a combination of superhydrophilic and superhydrophobic membranes was examined to further improve the removal of both hydrophobic and hydrophilic pollutants. With a combination of superhydrophilic and superhydrophobic membranes, the NOM rejection (RUV254) and DOC removal rates (RDOC) could be increased to 83.6% and 73.3%, respectively. PMID:26900973

  17. Equilibrium-phase precipitation behaviors of typical nickel-base alloys for 700 ℃ advanced ultra-supercritical boiler tubes%700℃以上超超临界电站锅炉过热器管材用典型镍基合金的平衡析出相规律

    Institute of Scientific and Technical Information of China (English)

    王珏; 董建新; 张麦仓; 谢锡善

    2012-01-01

    Thermodynamic equilibrium phase diagrams of three candidate materials, Incone1740, Inconel617, and GH2984, for 700 ℃ advanced ultra-supercritical boiler tubes were calculated by Thermo-Cale software and nickel-base alloy databases. Precipitation behaviors of phases in the three alloys were investigated by comparison. There are similar equilibrium phases in the three alloys, inclu- dingγ, γ', carbides, α,η , δ, μ, and α-Cr. Serious segregations of No, Ti and Nb may occur during solidification based on the calculation, which would decrease the initial melting points of the three alloys; therefore the consequent homogenization treatment is quite important. On the other hand, the amount of γ' precipitated in Incone1740 is higher than that in the other two alloys at 750 ℃. A1 and Ti eontents can strongly effeet the precipitation of γ and γ phases. The calculation of carbides indicates that primary carbides in Ineonel617 are different from those in the other two alloys, and the precipitation temperature range of secondary carbides in Ineonel617 is larger. The presence of of in GH2984 alloy is harmful to the rneehanical orooerties due to a higher Po enntont%利用热力学计算软件Thermo--Calc及镍基合金数据库,计算了三种700℃以上超超临界电站用过热器管道材料Inconel740、Inconel617和GH2984合金的热力学平衡相图,并对比了三种材料主要析出相的析出行为.计算结果表明:三种合金主要的析出相包括γ、γ'、碳化物、σ、η、δ、μ及α--Cr等,凝固过程中Mo、Nb和Ti元素偏析严重,会降低合金的初熔点,因此后期均匀化退火处理十分重要.另一方面,750℃时Inconel740合金γ'相析出量大于另外两种合金,并且Al和Ti含量对γ'相和η相析出行为有较大影响.碳化物的计算表明,Inconel617合金一次碳化物与另两种合金不同,并且其二次碳化物的析出温度范围最大.GH2984合金中Fe含量较大时会导致σ相出

  18. 等离子喷涂工艺对锅炉管束用Fe基非晶涂层组织结构和耐蚀性能的影响%Effect of Spray Process on the Microstructure and Corrosion-resistance of Fe-based Amorphous Coatings Obtained by Plasma Spray on the Boiler Tubes

    Institute of Scientific and Technical Information of China (English)

    高振; 郝建民; 韩建军; 鲁元; 陈永楠; 李世波

    2015-01-01

    ABSTRACT:Objective To investigate the effects of plasma spray power and time on the phase, microstructure and corrosion-re-sistance of the amorphous coating on the boiler tubes. Methods XRD, SEM and electrochemical polarization research were adopt-ed. Results The coating with high fraction of amorphous phase was obtained, which had a flat and compact surface. The amorphous fraction and porosity decreased and the density increased with the increasing spray power and time. The coatings exhibited an excel-lent ability to resist corrosion with wide passive region in 0. 5 mol/L H2 SO4 and 3. 5% NaCl solutions. And the coatings exhibited wider passive region and lower corrosion current density in 0. 5 mol/L H2 SO4 and 3. 5% NaCl solutions, respectively. With in-crease of the spray power and time, the anodic polarization curves of the amorphous coatings were passivated with wider passive re-gion and lower passive current density. Conclusion The path and flow resistance that corrosive liquid permeated the substrate were increased, and the corrosion resistance of the coating was improved, owing to the decreased porosity and increased coating thick-ness with the increasing spray power and time.%目的:研究等离子喷涂功率和喷涂时间对锅炉管束用Fe基非晶涂层的相组成、微观组织结构及涂层耐蚀性能的影响。方法通过X射线衍射、扫描电子显微镜和三电极电化学研究进行分析。结果涂层主要由非晶相组成,表面较为平整致密;随着喷涂功率和喷涂时间的增加,涂层非晶相含量降低,孔隙率降低,致密性升高。非晶涂层在0.5 mol/L H2SO4溶液和在3.5%(质量分数)NaCl溶液中均表现出良好的钝化作用,在0.5 mol/L H2 SO4溶液中钝化区较宽,在3.5%NaCl溶液中自腐蚀电流密度较低。随喷涂功率和时间的增加,阳极极化曲线钝化区加宽,电流密度降低。结论喷涂功率升高会导致涂层孔隙率下降

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

    Science.gov (United States)

    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.

  20. High Temperature Corrosion Problem of Boiler Components in presence of Sulfur and Alkali based Fuels

    Science.gov (United States)

    Ghosh, Debashis; Mitra, Swapan Kumar

    2011-04-01

    Material degradation and ageing is of particular concern for fossil fuel fired power plant components. New techniques/approaches have been explored in recent years for Residual Life assessment of aged components and material degradation due to different damage mechanism like creep, fatigue, corrosion and erosion etc. Apart from the creep, the high temperature corrosion problem in a fossil fuel fired boiler is a matter of great concern if the fuel contains sulfur, chlorine sodium, potassium and vanadium etc. This paper discusses the material degradation due to high temperature corrosion in different critical components of boiler like water wall, superheater and reheater tubes and also remedial measures to avoid the premature failure. This paper also high lights the Residual Life Assessment (RLA) methodology of the components based on high temperature fireside corrosion. of different critical components of boiler.

  1. Nature of fireside deposits in a bagasse and groundnut shell fired 20 MW thermal boiler

    International Nuclear Information System (INIS)

    The nature of deposit formation on the fireside surfaces of the boiler tubes in the various parts (water walls, platen superheater, final superheater, economizer, electrostatic precipitator etc.) of a commercial 20 MW stoker-fired boiler being fired with a mixture of 80% bagasse and 20% groundnut shell has been analyzed. The deposits in the various portions of the boiler were characterized by particle size analysis, chemical analysis, X-ray diffraction and scanning electron microscopy. The deposits were found to be mainly quartz, alkali and alkaline earth silicates and sulfates. From the phase constitution and other microscopic characteristics of the deposit, it can be inferred that the silicates in the deposit formed through inertial impaction and the sulfates formed by vapor phase deposition

  2. Ash Deposit Formation and Removal in a Straw and Wood Suspension-Fired Boiler

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming;

    by using an advanced online deposit probe in a full scale suspension-fired boiler using wood and straw pellets as fuel (Amageværket Unit 2, AMV2). The 250 MWth boiler has maximum capacity of 60t/h biomass, owned by Vattenfall, and located in Copenhagen, Denmark. The maximum operation period of boiler...... in the superheater region (1st draught, flue gas temperature, 820-865 °C) and in the tube bank region (2nd draught, flue gas temperature, 580-605 oC). The percentage of ash in the applied straw and wood was 5.9 % and 3.3 %, while the K contents were 0.81% and 0.09% respectively. During 35% straw share, the initial...

  3. Evaluation of tube shielding; Utvaerdering av tubskyddsmaterial

    Energy Technology Data Exchange (ETDEWEB)

    Hjoernhede, Anders; Westberg, Stig-Bjoern; Henderson, Pamela; Wetterstroem, Jonas; Jonasson, Anna

    2007-12-15

    Problems with soot-blowing have increased recently because of the poor fuel quality. Studies show that removing all the deposit by soot-blowing increases the metal loss of the superheaters, which drastically shortens component lifetimes. A simple, effective and common way of increasing the lifetime is to use tube shielding. Austenitic stainless steels seem to be the type of material most commonly used for tube shielding. It is thought that they give better protection against material removal than ferritic steels, but the cost of austenitics is several times greater than ferritic steels. It is clear that there is a significant economic advantage in choosing the right material for tube shielding, even though it might be expected that the cheaper materials do not perform as well as the more expensive ones. The reason for the study reported here is that very little material data exists in the literature. Few, if any tests have been performed to study the choice of material for tube shielding. The goal was to compare and evaluate a number of materials in a boiler to see if it is possible to replace the shielding material presently used with cheaper alternatives. About a dozen different shielding materials were installed and exposed for 4000 hours on primary- and secondary superheaters in a waste-fired boiler in Norrkoeping (Haendeloe Boiler 14.75MW). In total, 130 m of test material were installed and measured in several positions: a least 150 thickness measurements, before and after, were made on every tube shield. The results showed that the greatest attack was found on the secondary superheater shielding, where both the gas- and steam temperatures were higher. When considering cost and lifetime Sicromal 10 and 12 (however not Sicromal 8) and 15Mo3 are recommended as being better than 253 MA. The results should be of interest to most plants firing biomass or waste

  4. CFD modeling of fouling in crude oil pre-heaters

    International Nuclear Information System (INIS)

    Highlights: ► A conceptual CFD-based model to predict fouling in industrial crude oil pre-heaters. ► Tracing fouling formation in the induction and developing continuation periods. ► Effect of chemical components, shell-side HTC and turbulent flow on the fouling rate. - Abstract: In this study, a conceptual procedure based on the computational fluid dynamic (CFD) technique has been developed to predict fouling rate in an industrial crude oil pre-heater. According to the developed CFD concept crude oil was assumed to be composed of three pseudo-components comprising of petroleum, asphaltene and salt. The binary diffusion coefficients were appropriately categorized into five different groups. The species transport model was applied to simulate the mixing and transport of chemical species. The possibility of adherence of reaction products to the wall was taken into account by applying a high viscosity for the products in competition with the shear stress on the wall. Results showed a reasonable agreement between the model predictions and the plant data. The CFD model could be applied to new operating conditions to investigate the details of the crude oil fouling in the industrial pre-heaters.

  5. The new performance calculation method of fouled axial flow compressor.

    Science.gov (United States)

    Yang, Huadong; Xu, Hong

    2014-01-01

    Fouling is the most important performance degradation factor, so it is necessary to accurately predict the effect of fouling on engine performance. In the previous research, it is very difficult to accurately model the fouled axial flow compressor. This paper develops a new performance calculation method of fouled multistage axial flow compressor based on experiment result and operating data. For multistage compressor, the whole compressor is decomposed into two sections. The first section includes the first 50% stages which reflect the fouling level, and the second section includes the last 50% stages which are viewed as the clean stage because of less deposits. In this model, the performance of the first section is obtained by combining scaling law method and linear progression model with traditional stage stacking method; simultaneously ambient conditions and engine configurations are considered. On the other hand, the performance of the second section is calculated by averaged infinitesimal stage method which is based on Reynolds' law of similarity. Finally, the model is successfully applied to predict the 8-stage axial flow compressor and 16-stage LM2500-30 compressor. The change of thermodynamic parameters such as pressure ratio, efficiency with the operating time, and stage number is analyzed in detail. PMID:25197717

  6. In-line quantification and characterization of membrane fouling

    KAUST Repository

    Bucs, Szilard

    2016-06-16

    Methods of detecting, quantifying and/or characterizing the fouling of a device from a combination of pressure and spectroscopic data are provided. The device can be any device containing components susceptible to fouling. Components can include membranes, pipes, or reactors. Suitable devices include membrane devices, heat exchangers, and chemical or bio-reactors. Membrane devices can include, for example, microfiltration devices, ultrafiltration devices, nanofiltration devices, reverse osmosis, forward osmosis, osmosis, reverse electrodialysis, electro- deionisation or membrane distillation devices. The methods can be applied to any type of membrane, including tubular, spiral, hollow fiber, flat sheet, and capillary membranes. The spectroscopic characterization can include measuring one or more of the absorption, fluorescence, or raman spectroscopic data of one or more foulants. The methods can allow for the early detection and/or characterization of fouling. The characterization can include determining the specific foulant(s) or type of foulant(s) present. The characterization of fouling can allow for the selection of an appropriate de-fouling method and timing.

  7. The New Performance Calculation Method of Fouled Axial Flow Compressor

    Directory of Open Access Journals (Sweden)

    Huadong Yang

    2014-01-01

    Full Text Available Fouling is the most important performance degradation factor, so it is necessary to accurately predict the effect of fouling on engine performance. In the previous research, it is very difficult to accurately model the fouled axial flow compressor. This paper develops a new performance calculation method of fouled multistage axial flow compressor based on experiment result and operating data. For multistage compressor, the whole compressor is decomposed into two sections. The first section includes the first 50% stages which reflect the fouling level, and the second section includes the last 50% stages which are viewed as the clean stage because of less deposits. In this model, the performance of the first section is obtained by combining scaling law method and linear progression model with traditional stage stacking method; simultaneously ambient conditions and engine configurations are considered. On the other hand, the performance of the second section is calculated by averaged infinitesimal stage method which is based on Reynolds’ law of similarity. Finally, the model is successfully applied to predict the 8-stage axial flow compressor and 16-stage LM2500-30 compressor. The change of thermodynamic parameters such as pressure ratio, efficiency with the operating time, and stage number is analyzed in detail.

  8. Rejection of Organic Micropollutants by Clean and Fouled Nanofiltration Membranes

    Directory of Open Access Journals (Sweden)

    Lifang Zhu

    2015-01-01

    Full Text Available The rejection of organic micropollutants, including three polycyclic aromatic hydrocarbons (PAHs and three phthalic acid esters (PAEs, by clean and fouled nanofiltration membranes was investigated in the present study. The rejection of organic micropollutants by clean NF90 membranes varied from 87.9 to more than 99.9%, while that of NF270 membranes ranged from 32.1 to 92.3%. Clear time-dependence was observed for the rejection of hydrophobic micropollutants, which was attributed to the adsorption of micropollutants on the membrane. Fouling with humic acid had a negligible influence on the rejection of organic micropollutants by NF90 membranes, while considerable effects were observed with NF270 membranes, which are significantly looser than NF90 membranes. The observed enhancement in the rejection of organic micropollutants by fouled NF270 membranes was attributed to pore blocking, which was a dominating fouling mechanism for loose NF membranes. Changes in the ionic strength (from 10 to 20 mM reduced micropollutant rejection by both fouled NF membranes, especially for the rejection of dimethyl phthalate and diethyl phthalate by NF270 membranes (from 65.8 to 25.0% for dimethyl phthalate and 75.6 to 33.3% for diethyl phthalate.

  9. Black liquor combustion validated recovery boiler modeling: Final year report. Volume 2 (Appendices I, section 5 and II, section 1)

    Energy Technology Data Exchange (ETDEWEB)

    Grace, T.M.; Frederick, W.J.; Salcudean, M.; Wessel, R.A.

    1998-08-01

    This project was initiated in October 1990, with the objective of developing and validating a new computer model of a recovery boiler furnace using a computational fluid dynamics (CFD) code specifically tailored to the requirements for solving recovery boiler flows, and using improved submodels for black liquor combustion based on continued laboratory fundamental studies. The key tasks to be accomplished were as follows: (1) Complete the development of enhanced furnace models that have the capability to accurately predict carryover, emissions behavior, dust concentrations, gas temperatures, and wall heat fluxes. (2) Validate the enhanced furnace models, so that users can have confidence in the predicted results. (3) Obtain fundamental information on aerosol formation, deposition, and hardening so as to develop the knowledge base needed to relate furnace model outputs to plugging and fouling in the convective sections of the boiler. (4) Facilitate the transfer of codes, black liquid submodels, and fundamental knowledge to the US kraft pulp industry. Volume 2 contains the last section of Appendix I, Radiative heat transfer in kraft recovery boilers, and the first section of Appendix II, The effect of temperature and residence time on the distribution of carbon, sulfur, and nitrogen between gaseous and condensed phase products from low temperature pyrolysis of kraft black liquor.

  10. CFD Simulation On CFBC Boiler

    OpenAIRE

    Amol S. Kinkar; G. M. Dhote; R.R. Chokkar

    2015-01-01

    Abstract Heavy industrialization amp modernization of society demands in increasing of power cause to research amp develop new technology amp efficient utilization of existing power units. Variety of sources are available for power generation such as conventional sources like thermal hydro nuclear and renewable sources like wind tidal biomass geothermal amp solar. Out of these most common amp economical way for producing the power is by thermal power stations. Various industrial boilers plays...

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

    Science.gov (United States)

    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.

  12. Treatment of hazardous and toxic liquids using Rochem Disc Tube technology

    International Nuclear Information System (INIS)

    Rochem Separation Systems, established in 1990 as a subsidiary of the international Rochem Group, has advanced the treatment of hazardous and toxic liquids with its unique, patented Disc Tube technology. Developed in 1987 at Rochem's design and production facilities in Hamburg, Germany, the Disc Tube technology is a series of membrane modules that greatly reduce the problems that hamper the effectiveness of other treatment technologies (i.e. fouling, scaling, cost, etc.). Applications of the Disc Tube technology include reverse osmosis and ultrafiltration. Rochem was recently accepted into the EPA Superfund Site program as a result of its Disc Tube technology. 1 fig., 1 tab

  13. Developing Boiler Concepts as Integrated Units

    DEFF Research Database (Denmark)

    Sørensen, Kim; Condra, Thomas Joseph; Houbak, Niels

    2004-01-01

    With the objective to be able to optimize the design and operation of steam boiler concepts Aalborg Industries A/S [1] has together with Aalborg University, Institute of Energy Technology [9] carried out a development project paying special attention to the boiler concept as an integrated unit...... - consisting of pressure part, burner and control system. The Technical University of Denmark, MEK - Energy Engineering Section [12] has participated in the modelling process. The project has included static and dynamic modelling of the boiler concept. For optimization of operation, verication of performance...... bricks in the boiler concept to each other and hereby obtain signicant reductions in the boiler concepts weight and foot-print . The actual development project has focused on an heavy fuel oil-red boiler for the marine market with a capacity in the range 1-10 t/h saturated steam. The development project...

  14. Inception report and gap analysis. Boiler inspection

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-06-01

    This inception and gap analysis report on boilers in Latvia, has been prepared in the framework of the 'Implementation of the EU directive on energy performance of buildings: development of the Latvian Scheme for energy auditing of building and inspection of boilers'. The report is the basis for the establishment of training of boiler inspectors; it develops a gap analysis for better understanding and estimating the number of installations in Latvia and develops suggestions for the institutional set up. In particular includes information on existing standard and regulation on boiler, suggestion for the content of the training material of experts for boiler inspections and a syllabus of the training course. A specific section is dedicated to the suggestion for certification system of trained boiler inspectors. (au)

  15. Gastrostomy Tube (G-Tube)

    Science.gov (United States)

    ... endoscope (a thin, flexible tube with a tiny camera and light at the tip) inserted through the ... Nemours Foundation, iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart.com

  16. Ear tube insertion

    Science.gov (United States)

    Myringotomy; Tympanostomy; Ear tube surgery; Pressure equalization tubes; Ventilating tubes; Ear infection - tubes; Otitis - tubes ... trapped fluid can flow out of the middle ear. This prevents hearing loss and reduces the risk ...

  17. Fouling Characterization of Forward Osmosis Biomimetic Aquaporin Membranes Used for Water Recovery from Municipal Wastewater

    DEFF Research Database (Denmark)

    Zarebska, Agata; Petrinic, Irena; Hey, Tobias;

    Spectrometry, Fourier Transform Infrared Spectrometry, Inductively Coupled Plasma Optical Emission Spectrometry, Ion chromatography, zeta potential, and contact angle measurements. Our preliminary experimental results indicate that FO membrane fouling is dominated by organic fouling caused by adsorption...

  18. Grafting polymer brushes on biomimetic structural surfaces for anti-algae fouling and foul release.

    Science.gov (United States)

    Wan, Fei; Pei, Xiaowei; Yu, Bo; Ye, Qian; Zhou, Feng; Xue, Qunji

    2012-09-26

    Sylgard-184 silicone elastomer negative replica and resorcinol-formaldehyde (RF) positive replica were made by biomimicking the patterns of natural Trifolium and three other kinds of leaves using the micromolding lithography. An effective antifouling (AF) polymer, poly(3-sulfopropyl methacrylate) (PSPMA), was then grafted on these replica surfaces via the surface-initiated atom transfer radical polymerization (SI-ATRP). The AF property of the modified biomimetic surfaces was tested via the settlement assay with two microalgae in different sizes, and their fouling-release (FR) property was evaluated by the removal assay. The results indicate that the structure of microspines on Trifolium leaf can inhibit settlement of microalgae and facilitate the cell release. The AF property was improved by modification with PSPMA brushes. PMID:22931043

  19. Grafting polymer brushes on biomimetic structural surfaces for anti-algae fouling and foul release.

    Science.gov (United States)

    Wan, Fei; Pei, Xiaowei; Yu, Bo; Ye, Qian; Zhou, Feng; Xue, Qunji

    2012-09-26

    Sylgard-184 silicone elastomer negative replica and resorcinol-formaldehyde (RF) positive replica were made by biomimicking the patterns of natural Trifolium and three other kinds of leaves using the micromolding lithography. An effective antifouling (AF) polymer, poly(3-sulfopropyl methacrylate) (PSPMA), was then grafted on these replica surfaces via the surface-initiated atom transfer radical polymerization (SI-ATRP). The AF property of the modified biomimetic surfaces was tested via the settlement assay with two microalgae in different sizes, and their fouling-release (FR) property was evaluated by the removal assay. The results indicate that the structure of microspines on Trifolium leaf can inhibit settlement of microalgae and facilitate the cell release. The AF property was improved by modification with PSPMA brushes.

  20. Research of Boiler Combustion Regulation for Reducing Nox Emission and its Effect on Boiler Efficiency

    Institute of Scientific and Technical Information of China (English)

    WANG Xue-dong; LUAN Tao; CHENG Lin; XIAO Kun

    2007-01-01

    The effect of boiler combustion regulation on Nox emission of two 1025t/h boilers has been studied. The researches show that Nox emission is influenced by coal species, operation conditions, etc, and can be reduced by regulating the combustion conditions. The effect of combustion regulation on boiler efficiency has also been checked.

  1. WASTE HEAT RECOVERY FROM BOILER OF LARGE-SCALE TEXTILE INDUSTRY

    Directory of Open Access Journals (Sweden)

    Prateep Pattanapunt

    2013-01-01

    Full Text Available Many industrial heating processes generate waste energy in textile industry; especially exhaust gas from the boiler at the same time reducing global warming. Therefore, this article will present a study the way to recovery heat waste from boiler exhaust gas by mean of shell and tube heat exchanger. Exhaust gas from boiler dyeing process, which carries a large amount of heat, energy consumptions could be decrease by using of waste-heat recovery systems. In this study, using ANASYS simulation performs a thermodynamics analysis. An energy-based approach is performed for optimizing the effective working condition for waste-heat recovery with exhaust gas to air shell and tube heat exchanger. The variations of parameters, which affect the system performance such as, exhaust gas and air temperature, velocity and mass flow rate and moisture content is examined respectively. From this study, it was found that heat exchanger could be reduced temperature of exhaust gases and emission to atmosphere and the time payback is the fastest. The payback period was determined about 6 months for investigated ANSYS. The air is circulated in four passes from the top to the bottom of the test section, in overall counter-flow with exhaust gas. The front area is 1720×1720 mm, the flow length 7500 mm, the inner and outer diameter of exhaust gas is 800 mm, the tube assembly consist of 196 tubes, the tube diameter is 76.2 mm, the tube thickness is 2.6 mm, the tube length is 4500 mm, the tube length of air inner and outer is 500 mm. The result show that, the boiler for superheated type there are exhaust gas temperature is 190°C, 24% the moisture content of fuel and there are palm kernel shell 70 tons day-1 which there are the high temperature after the heat exchanger, 150°C. It was occurred acid rain. The hot air from heat exchanger process can be reduced the moisture of palm kernel shell fuel to 15%.The fuel consumption is reduced by about 2.05% (322.72 kJ kg-1

  2. Industrial fouling: problem characterization, economic assessment, and review of prevention, mitigation, and accommodation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Garrett-Price, B.A.; Smith, S.A.; Watts, R.L.

    1984-02-01

    A comprehensive overview of heat exchanger fouling in the manufacturing industries is provided. Specifically, this overview addresses: the characteristics of industrial fouling problems; the mitigation and accommodation techniques currently used by industry; and the types and magnitude of costs associated with industrial fouling. A detailed review of the fouling problems, costs and mitigation techniques is provided for the food, textile, pulp and paper, chemical, petroleum, cement, glass and primary metals industries.

  3. Fouling Kinetics and Associated Dynamics of Structural Modifications

    DEFF Research Database (Denmark)

    Jacob, Jerome; Prádanos, Pedro; Calvo, J. I.;

    1998-01-01

    by Sartorius (ST02 and ST045, neutral) and Spectrum (SP02 and SP045, positively charged) when fouled by permeating a protein aqueous solution (bovine serum albumin (BSA) at 1 g l(-1)) under 10 kPa in a dead-end device. The structure after different fouling times is obtained by using an extended bubble point...... method, and the equilibrium (BSA at both 1 g l(-1) and 10 g l(-1) concentrations) and dynamical adsorption, along with the equivalent number of layers, are investigated. (C) 1998 Elsevier Science B.V....

  4. A Study on CaSO4 Fouling Deposit

    Institute of Scientific and Technical Information of China (English)

    RenXiaoguang; LiCuiqing; LiuChanghou

    2002-01-01

    This paper reports the influences of heat transfer surface properties on the formation of CaSO4 fouling deposition during flow boiling heat transfer.The surfaces of several test heaters have been treated by surface modification techniques.such as dynamic mixing ion beam implantation and dynamic mixing magnetron sputtering to reduce surface energy.Fouling runs with these heaters were carried out at different heat fluxes,flow velocities and salt concentrations.The results show that heat transfer surfaces with low surface energy experienced significantly a reduced formation of CaSO4 deposit.

  5. Cleaning protocol for a FO membrane fouled in wastewater reuse

    KAUST Repository

    Valladares Linares, Rodrigo

    2013-05-30

    Forward osmosis (FO) is an emerging technology which can be applied in water reuse applications. Osmosis is a natural process that involves less energy consumption than reverse osmosis (RO), and therefore can be applied as a dilution process before low-pressure RO; it is expected to compete favourably against current advanced water reuse technologies that use microfiltration/ultrafiltration and RO. The focus of this research was to assess the efficiency of different cleaning procedures to remove fouling from the surface of a FO membrane during the operation of a submerged system working in FO-mode (active layer (AL) facing feed solution) intended for secondary wastewater effluent (SWWE) recovery, using seawater as draw solution (DS), which will be diluted and can further be fed to a low-pressure RO unit to produce fresh water. Natural organic matter (NOM) fouling was expected to affect the AL, while for the support layer (SL), transparent exopolymer particles (TEP) were used as indicators of fouling due to their stickiness and propensity to enhance the attachment of other foulants in seawater on the membrane surface. The composition of the NOM fouling layer was determined after proper characterisation with a liquid chromatograph coupled with organic carbon detection (LC-OCD), showing biopolymers and protein-like substances as the main constituents. NOM fouling showed high hydraulic reversibility after a 25% flux decline was observed, up to 89.5% when in situ air scouring for 15 min was used as a cleaning technique. Chemical cleaning with a mixture of Alconox, an industrial detergent containing phosphates, and sodium EDTA showed to increase the reversibility (93.6%). Osmotic backwash using a 4% NaCl solution and DI water proved to be ineffective to recover flux due to the salt diffusion phenomena occurring at the AL. Part of the flux that could not be recovered is attributable to TEP fouling on the SL, which forms clusters clearly identifiable with an optical

  6. Measurement Methodology for Monitoring Fouling Resistance in Condenser of Chiller

    Institute of Scientific and Technical Information of China (English)

    YU Dan; GAN Li-si; CAO Yong

    2009-01-01

    This paper established an on-line monitoring model for fouling resistance of cooling water based on heat transfer theory,which was mainly applied to the fouling resistance test for condenser of chiller in operation,and the test requirements were presented.It proves that the load ratio of chiller has big influence on the test re-sult,and the best load ratio for test is the range of 80%~100%.A case has been executed to validate the mod-el's feasibility.

  7. A new concept for anti-fouling paint for Yachts

    DEFF Research Database (Denmark)

    Wallstroem, Eva; Jespersen, Henrik T.; Schaumburg, Kjeld

    2011-01-01

    -fouling products for yachts. To be able to reduce the amount of biocide, in this case zinc pyrithione, it is necessary to have control over the amount of biocide present in the surface layer. The control is achieved by encapsulating the biocide in a silica gel. The silica gel is dispersed together with pigments...... it is encapsulated in a gel compared to a situation where it is not. This conclusion is based on the fact that the gel swells when exposed to water, and therefore the leach of zinc pyrithione is initially delayed and the biocide may start to solubilise and degrade. The result is an anti-fouling product...

  8. Fouling-induced enzyme immobilization for membrane reactors

    DEFF Research Database (Denmark)

    Luo, Jianquan; Meyer, Anne S.; Jonsson, Gunnar Eigil;

    2013-01-01

    A simple enzyme immobilization method accomplished by promoting membrane fouling formation is proposed. The immobilization method is based on adsorption and entrapment of the enzymes in/on the membrane. To evaluate the concept, two membrane orientations, skin layer facing feed (normal mode......, but the reverse mode allowed for higher enzyme loading and stability, and irreversible fouling (i.e. pore blocking) developed more readily in the support structure than in the skin layer. Compared with an enzymatic membrane reactor (EMR) with free enzymes, the novel EMR with enzymes immobilized in membrane...... support improved the enzyme reusability (especially for ADH), and reduced the product inhibition (especially for GDH). © 2013 Elsevier Ltd....

  9. A New Concept of Ultrafiltration Fouling Control: Backwashing with Low Ionic Strength Water

    NARCIS (Netherlands)

    Li, S.

    2011-01-01

    Ultrafiltration (UF) is a proven technology in water treatment nowadays. However, fouling remains a major challenge in the operation of UF, especially in regard to colloidal NOM fouling. In general, a number of colloidal NOM fouling mechanisms may occur, such as adsorption, gel formation. Colloidal

  10. Black liquor combustion validated recovery boiler modeling: Final year report. Volume 1 (Main text and Appendix I, sections 1--4)

    Energy Technology Data Exchange (ETDEWEB)

    Grace, T.M.; Frederick, W.J.; Salcudean, M.; Wessel, R.A.

    1998-08-01

    This project was initiated in October 1990, with the objective of developing and validating a new computer model of a recovery boiler furnace using a computational fluid dynamics (CFD) code specifically tailored to the requirements for solving recovery boiler flows, and using improved submodels for black liquor combustion based on continued laboratory fundamental studies. The key tasks to be accomplished were as follows: (1) Complete the development of enhanced furnace models that have the capability to accurately predict carryover, emissions behavior, dust concentrations, gas temperatures, and wall heat fluxes. (2) Validate the enhanced furnace models, so that users can have confidence in the predicted results. (3) Obtain fundamental information on aerosol formation, deposition, and hardening so as to develop the knowledge base needed to relate furnace model outputs to plugging and fouling in the convective sections of the boiler. (4) Facilitate the transfer of codes, black liquid submodels, and fundamental knowledge to the US kraft pulp industry. Volume 1 contains the main body of the report and the first 4 sections of Appendix 1: Modeling of black liquor recovery boilers -- summary report; Flow and heat transfer modeling in the upper furnace of a kraft recovery boiler; Numerical simulation of black liquor combustion; and Investigation of turbulence models and prediction of swirling flows for kraft recovery furnaces.

  11. Loss of feed flow, steam generator tube rupture and steam line break thermohydraulic experiments

    Energy Technology Data Exchange (ETDEWEB)

    Mendler, O J; Takeuchi, K; Young, M Y

    1986-10-01

    The Westinghouse Model Boiler No. 2 (MB-2) steam generator test model at the Engineering Test Facility in Tampa, Florida, was reinstrumented and modified for performing a series of tests simulating steam generator accident transients. The transients simulated were: loss of feed flow, steam generator tube rupture, and steam line break events. This document presents a description of (1) the model boiler and the associated test facility, (2) the tests performed, and (3) the analyses of the test results.

  12. Loss of feed flow, steam generator tube rupture and steam line break thermohydraulic experiments

    International Nuclear Information System (INIS)

    The Westinghouse Model Boiler No. 2 (MB-2) steam generator test model at the Engineering Test Facility in Tampa, Florida, was reinstrumented and modified for performing a series of tests simulating steam generator accident transients. The transients simulated were: loss of feed flow, steam generator tube rupture, and steam line break events. This document presents a description of (1) the model boiler and the associated test facility, (2) the tests performed, and (3) the analyses of the test results

  13. Ear Tubes

    Science.gov (United States)

    ... of the ear drum or eustachian tube, Down Syndrome, cleft palate, and barotrauma (injury to the middle ear caused by a reduction of air pressure, ... specialist) may be warranted if you or your child has experienced repeated ... fluid in the middle ear, barotrauma, or have an anatomic abnormality that ...

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

    Science.gov (United States)

    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.

  15. Researchers examine problems of foul tastes when undergoing chemotherapy

    OpenAIRE

    Nystrom, Lynn A.

    2006-01-01

    About two million cancer patients currently receiving certain drug therapies and chemotherapy will consume foods and beverages and find the taste to have a foul metallic flavor, according to a medical study. In general, more than 40 percent of hospitalized patients suffer from malnutrition due to taste and smell dysfunction.

  16. Two-dimensional stochastic modeling of membrane fouling

    NARCIS (Netherlands)

    Wessling, M.

    2001-01-01

    The phenomenon of fouling of microfiltration membranes by much smaller particles such as proteins is described by a new developed simulation algorithm based on diffusion limited aggregation simulation techniques. The model specifies the membrane morphology explicitly and allows to (a) characterize t

  17. CHEMICAL CLEANING OF NANOFILTRATION MEMBRANES FOULED BY ORGANIC MATTERS

    Directory of Open Access Journals (Sweden)

    CHARLENE C. H. KOO

    2016-07-01

    Full Text Available Membrane fouling is a term to describe non-integral substance on membrane surface which results in rapid decline of permeation flux and deteriorate the performance of membrane. Chemical cleaning agents especially like alkaline cleaners are most widely employed to restore the membrane performance. This research mainly investigated the potential use of sodium hydroxide (NaOH and sodium hypochlorite (NaOCl as the chemical cleaning agents to restore the permeate flux of organically fouled nanofiltration (NF membranes under varying applied pressure and flow condition. The performances of the cleaning protocols were quantified using flux recovery and resistance removal. The results demonstrated that NaOCl is more effective than NaOH. This observation is also in line with FTIR analysis in which the transmittance intensity showed by FTIR spectra of NaOCl is higher than that of NaOH. The results also reported that higher flux recovery and resistance removal were achieved when the fouled NF membranes were cleaned with higher concentration of chemical agents and applied pressure. However, the improvements of flux recovery and resistance removal by increasing the applied pressure were found insignificant at higher applied pressure range (16 to 18 bar than the lower applied pressure range (i.e. 12 to 14 bar. This research plays an important role by identifying the key parameters that could restore the flux of organically fouled NF membranes significantly.

  18. Fouling acorn barnacles in China——a review

    Institute of Scientific and Technical Information of China (English)

    CAO Wenhao; YAN Tao; LI Zufu; LI Jing; CHENG Zhiqiang

    2013-01-01

    We review the species composition,distribution,and seasonal variation of fouling acorn barnacles in Chinese waters—from Bohai Sea and Yellow Sea to East and South China Seas.Thirty-two species of acorn barnacles were found,of which,the dominant species are Amphibalanus amphitrite,A.reticulatus,A.variegates,Balanus trigonus,Fistulobalanus kondakovi,Megabalanus tintinnabulum,Striatobalanus amaryllis,and Eurapha withersi in the fouling communities.A.amphitrite is the dominant species in the coastal waters of Bohai Sea and Yellow Sea and A.reticulatus is dominant in the East and South China Seas.The settlement period of fouling acorn barnacles is usually in summer and autumn.From north to south with the decrease of latitude,their settlement period obviously extends,even to the whole year,and the species number also increases.Other environmental factors,such as salinity and distance from shore,also play an important role in the distribution of fouling acorn barnacles.

  19. EFFECT OF CHLORAMINATION AND SEASONAL WATER CHANGES ON NANOFILTRATION FOULING

    Science.gov (United States)

    Nanofiltraton membrane studies conducted with Little Miami Aquifer water from the Indian Hill Water Works (OH) showed tht flux loss was highly seasonal in nature with the greatest fouling occurring during the highest water temperatures during drought conditions. The reason for th...

  20. Fuel efficiency and fouling control coatings in maritime transport

    DEFF Research Database (Denmark)

    Lindholdt, Asger

    First, this thesis concerns the drag performance of fouling control coatings (FCCs) used to protect hulls on ships against biofouling and, therefore, minimize any drag therefrom. A systematic overview of the literature and description of the experimental methods used to quantify the drag of FCCs...

  1. Influence of membrane properties on fouling in submerged membrane bioreactors

    NARCIS (Netherlands)

    Marel, van der P.; Zwijnenburg, A.; Kemperman, A.; Wessling, M.; Temmink, B.G.; Meer, van der W.

    2010-01-01

    Polymeric flat-sheet membranes with different properties were used in filtration experiments with activated sludge from a pilot-scale MBR to investigate the influence of membrane pore size, surface porosity, pore morphology, and hydrophobicity on membrane fouling. An improved flux-step method was us

  2. 46 CFR 109.555 - Propulsion boilers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Propulsion boilers. 109.555 Section 109.555 Shipping... Miscellaneous § 109.555 Propulsion boilers. The master or person in charge and the engineer in charge shall ensure that— (a) Steam pressure does not exceed that allowed by the certificate of inspection; and...

  3. Membrane fouling mechanism transition in relation to feed water composition

    KAUST Repository

    Myat, Darli Theint

    2014-12-01

    The impact of secondary effluent wastewater from the Eastern Treatment Plant (ETP), Melbourne, Australia, before and after ion exchange (IX) treatment and polyaluminium chlorohydrate (PACl) coagulation, on hydrophobic polypropylene (PP) and hydrophilic polyvinylidene fluoride (PVDF) membrane fouling was studied. Laboratory fouling tests were operated over 3-5 days with regular, intermittent backwash. During the filtration with PP membranes, organic rejection data indicated that humic adsorption on hydrophobic PP membrane occurred during the first 24h of filtration and contributed to fouling for both raw wastewater and pre-treated wastewaters. However, after the first 24h of filtration the contribution of humic substances to fouling diminished and biopolymers that contribute to cake layer development became more prominent in their contribution to the fouling rate. For PVDF membranes, the per cent removal of humic substances from both raw wastewater and pre-treated wastewaters was very small as indicated by no change in UV254 from the feed to the permeate over the filtration period, even during the early stages of filtration. This suggested that the hydrophobic PP membrane adsorbed humic substances while the hydrophilic PVDF membrane did not. The highest mass of biopolymer removal by each PVDF membrane was from ETP water followed by PACl and IX treated water respectively. This was possibly due to differences in the backwashing efficiency linked to the filter cake contributed by biopolymers. Hydraulic backwashing was more effective during the later stages of filtration for the ETP water compared to IX and PACl treated waters, indicating that the filter cake contributed by ETP biopolymers was more extensively removed by hydraulic backwashing. It was proposed that humic substances may act to stabilise biopolymers in solution and that removing humics substances by coagulation or IX results in greater adhesive forces between the biopolymers and membrane/filter cake

  4. Effect of oxygen on fouling behavior in lead bismuth coolant systems

    Science.gov (United States)

    Niu, Fenglei; Candalino, Robert; Li, Ning

    2007-06-01

    This experimental research investigates the effects of the oxygen in lead-bismuth eutectic on fouling. The analysis was carried out by performing three tests with different oxygen concentration on the recuperator where the heat transfer rate is susceptible to fouling, and introducing a correlation for the fouling factor. The comparison of fouling factors obtained with each oxygen level is presented, the relationship between fouling factors and oxygen concentrations is correlated, and the effects of oxidation on heat transfer are demonstrated qualitatively by wetting conditions of the samples.

  5. Safety issues arising from the corrosion-fatigue of waterwall tubes

    Energy Technology Data Exchange (ETDEWEB)

    Brear, J. M.; Jarvis, P. (Stress Engineering Services (Europe) Limited, Chichester (United Kingdom)); Scully, S. (Electricity Supply Board, Dublin (Ireland))

    2010-05-15

    An incidence of waterwall tube failures, one leading to a significant steam release external to the boiler, has highlighted the need for rigorous risk assessment of such events. Initial review of the utility's experience revealed one of their boiler designs as having had a greater incidence of corrosion-fatigue issues in waterwall tubing than the others. These units were treated as a priority. To address failure likelihood, fracture mechanics calculations were performed. These studies defined the necessary inspection coverage and sensitivity required to underwrite safe operation at various potential loads. Personnel safety was considered the most important consequence of failure. Accordingly, potential steam releases were modelled to define safe exclusion zones within the boiler house. Standard calculations were found to be nonconservative; more exact formulae were needed to give realistic results. Using the results of these studies, the utility was able to draw up a realistic inspection plan. Safe operating pressures and appropriate exclusion zones were defined for each boiler, and for a range of operational scenarios. These tactics have allowed the utility to inspect the boilers in turn and to repair all significant defects in the waterwall tubes, whilst maintaining a good overall power output. In parallel, a root-cause investigation was performed to identify the factors contributing to the failures. Where possible, causative influences were reduced or mitigated so as to reduce the likelihood of failure whilst allowing increased flexibility of boiler operation. (orig.)

  6. Rejection of micropollutants by clean and fouled forward osmosis membrane.

    Science.gov (United States)

    Valladares Linares, Rodrigo; Yangali-Quintanilla, Victor; Li, Zhenyu; Amy, Gary

    2011-12-15

    As forward osmosis (FO) gains attention as an efficient technology to improve wastewater reclamation processes, it is fundamental to determine the influence of fouling in the rejection of emerging contaminants (micropollutants). This study focuses on the rejection of 13 selected micropollutants, spiked in a secondary wastewater effluent, by a FO membrane, using Red Sea water as draw solution (DS), differentiating the effects on the rejection caused by a clean and fouled membrane. The resulting effluent was then desalinated at low pressure with a reverse osmosis (RO) membrane, to produce a high quality permeate and determine the rejection with a coupled forward osmosis - low pressure reverse osmosis (FO-LPRO) system. When considering only FO with a clean membrane, the rejection of the hydrophilic neutral compounds was between 48.6% and 84.7%, for the hydrophobic neutrals the rejection ranged from 40.0% to 87.5%, and for the ionic compounds the rejections were between 92.9% and 96.5%. With a fouled membrane, the rejections were between 44.6% and 95.2%, 48.7%-91.5% and 96.9%-98.6%, respectively. These results suggest that, except for the hydrophilic neutral compounds, the rejection of the micropollutants is increased by the presence of a fouling layer, possibly due to the higher hydrophilicity of the FO fouled membrane compared to the clean one, the increased adsorption capacity of hydrophilic compounds and reduced mass transport capacity, membrane swelling, and the higher negative charge of the membrane surface, related to the foulants composition, mainly NOM acids (carboxylic radicals) and polysaccharides or polysaccharide-like substances. However, when coupled with RO, the rejections in both cases increased above 96%. The coupled FO-LPRO system was an effective double barrier against the selected micropollutants. PMID:22055122

  7. Rejection of micropollutants by clean and fouled forward osmosis membrane

    KAUST Repository

    Valladares Linares, Rodrigo

    2011-12-01

    As forward osmosis (FO) gains attention as an efficient technology to improve wastewater reclamation processes, it is fundamental to determine the influence of fouling in the rejection of emerging contaminants (micropollutants). This study focuses on the rejection of 13 selected micropollutants, spiked in a secondary wastewater effluent, by a FO membrane, using Red Sea water as draw solution (DS), differentiating the effects on the rejection caused by a clean and fouled membrane. The resulting effluent was then desalinated at low pressure with a reverse osmosis (RO) membrane, to produce a high quality permeate and determine the rejection with a coupled forward osmosis - low pressure reverse osmosis (FO-LPRO) system. When considering only FO with a clean membrane, the rejection of the hydrophilic neutral compounds was between 48.6% and 84.7%, for the hydrophobic neutrals the rejection ranged from 40.0% to 87.5%, and for the ionic compounds the rejections were between 92.9% and 96.5%. With a fouled membrane, the rejections were between 44.6% and 95.2%, 48.7%-91.5% and 96.9%-98.6%, respectively. These results suggest that, except for the hydrophilic neutral compounds, the rejection of the micropollutants is increased by the presence of a fouling layer, possibly due to the higher hydrophilicity of the FO fouled membrane compared to the clean one, the increased adsorption capacity of hydrophilic compounds and reduced mass transport capacity, membrane swelling, and the higher negative charge of the membrane surface, related to the foulants composition, mainly NOM acids (carboxylic radicals) and polysaccharides or polysaccharide-like substances. However, when coupled with RO, the rejections in both cases increased above 96%. The coupled FO-LPRO system was an effective double barrier against the selected micropollutants. © 2011 Elsevier Ltd.

  8. Desulphurization in peat-fired circulating and bubbling fluidized bed boilers

    Energy Technology Data Exchange (ETDEWEB)

    Kouvo, P. [Imatran Voima Oy, Vantaa (Finland); Salmenoja, K. [Kvaerner Pulping Oy, Tampere (Finland)

    1997-12-31

    The new emission limit values for large combustion plants are under consideration both at the EU level and in Finland. Peat and wood are the only indigenous fuels of Finland. In 1995 appr. 8 % of electricity was produced with peat. The lower heating value of peat is around 10 MJ/kg. The moisture content varies between 35-55 % and sulphur content in dry solids between 0.15-0.35 %. The total peat power capacity of Finland in 1995 was 1400 MW. Because there was not enough information available about the desulphurization of the flue gases from peat-fired fluidized bed boilers, a group of Finnish companies and Ministry of Trade and Industry decided to carry out the full-scale desulphurisation study. In the project the desulphurization with limestone injection into the furnace of two types of peat-fired boilers were studied. The goal of the project was to investigate: what the technically and economically feasible emission level is by limestone injection in the fluidized bed combustion; how the limestone injection affects the other flue gas emissions and the fouling of the boiler and, what the economy of desulphurisation is. The tests were carried out at Kokkola and Kemi power plants in Finland. At Kokkola (108 MW{sub f}) circulating fluidized bed boiler, the emission limit of 200 mg/m{sup 3}n was leached at a Ca/S-molar ratio of appr. 10, with limestone containing 92 % of calcium carbonate, CaCO{sub 3}. At Kemi (267 MW{sub f}) bubbling fluidized bed boiler, the emission limit of 280 mg/m{sup 3}n with limestone containing appr. 95 % of CaCO{sub 3} was reached at a Ca/S-molar ratio of appr. 7.0. Emissions of NO{sub x}, N{sub 2}O, NH{sub 3} and dust after the ESP were not elevated due to the limestone feed. At the Kokkola power plant the NO{sub x} emissions varied from 300 to 400 mg/m{sup 3}n, and, at the Kemi power station the NO{sub x} emissions were around 200 mg/m{sup 3}n. The fouling of the Kemi boiler was found to be significant in the scheduled outage after the test

  9. PAH emission from the industrial boilers.

    Science.gov (United States)

    Li, C; Mi, H; Lee, W; You, W; Wang, Y

    1999-10-01

    Polycyclic aromatic hydrocarbons (PAHs) emitted from 25 industrial boilers were investigated. The fuels used for these 25 boilers included 21 heavy oil, two diesel, a co-combustion of heavy oil and natural gas (HO+NG) and a co-combustion of coke oven gas and blast furnace gas (COG+BFG) boilers. PAH samples from the stack flue gas (gas and particle phases) of these 25 boilers were collected by using a PAH stack sampling system. Twenty one individual PAHs were analyzed primarily by a gas chromatography/mass spectrometer (GC/MS). Total-PAH concentration in the flue gas of 83 measured data for these 25 boiler stacks ranged between 29.0 and 4250 microg/m(3) and averaged 488 microg/m(3). The average of PAH-homologue mass (F%) counted for the total-PAH mass was 54.7%, 9.47% and 15.3% for the 2-ring, 3-ring and 4-ring PAHs, respectively. The PAHs in the stack flue gas were dominant in the lower molecular weight PAHs. The emission factors (EFs) of total-PAHs were 13,300, 2920, 2880 and 208 microg/kg-fuel for the heavy oil, diesel, HO+NG and COG+BFG fueled-boiler, respectively. Nap was the most predominant PAH occurring in the stack flue gas. In addition, the EF of 21 individual PAHs in heavy-oil boiler were almost the highest among the four various fueled-boilers except for those of FL and BkF in the diesel boiler. Furthermore, the EF of total-PAHs or BaP for heavy oil were both one order of magnitude higher than that for the diesel-fueled boiler.

  10. Nanoparticle fouling and its combination with organic fouling during forward osmosis process for silver nanoparticles removal from simulated wastewater

    Science.gov (United States)

    Zhao, Yanxiao; Wang, Xinhua; Wang, Zhiwei; Li, Xiufen; Ren, Yueping

    2016-05-01

    The increasing and wide application of silver nanoparticles (Ag NPs) has resulted in their appearance in wastewater. In consideration of their potential toxicity and environmental impacts, it is necessary to find effective technology for their removal from wastewater. Here, forward osmosis (FO) membrane was applied for Ag NPs removal from wastewater, and single and combined fouling of nanoparticles and organic macromolecules were further investigated during the FO process. The findings demonstrated that FO membrane can effectively remove Ag NPs from wastewater due to its high rejection performance. Fouling tests indicated that water flux declined appreciably even at the beginning of the single Ag NPs fouling test, and more remarkable flux decline and larger amounts of deposited Ag NPs were observed with an increase of Ag NPs concentration. However, the addition of bovine serum albumin (BSA) could effectively alleviate the FO membrane fouling induced by Ag NPs. The interaction between Ag NPs and BSA was responsible for this phenomenon. BSA can easily form a nanoparticle-protein corona surrounded nanoparticles, which prevented nanoparticles from aggregation due to the steric stabilization mechanism. Furthermore, the interaction between BSA and Ag NPs occurred not only in wastewater but also on FO membrane surface.

  11. Nanoparticle fouling and its combination with organic fouling during forward osmosis process for silver nanoparticles removal from simulated wastewater

    Science.gov (United States)

    Zhao, Yanxiao; Wang, Xinhua; Wang, Zhiwei; Li, Xiufen; Ren, Yueping

    2016-01-01

    The increasing and wide application of silver nanoparticles (Ag NPs) has resulted in their appearance in wastewater. In consideration of their potential toxicity and environmental impacts, it is necessary to find effective technology for their removal from wastewater. Here, forward osmosis (FO) membrane was applied for Ag NPs removal from wastewater, and single and combined fouling of nanoparticles and organic macromolecules were further investigated during the FO process. The findings demonstrated that FO membrane can effectively remove Ag NPs from wastewater due to its high rejection performance. Fouling tests indicated that water flux declined appreciably even at the beginning of the single Ag NPs fouling test, and more remarkable flux decline and larger amounts of deposited Ag NPs were observed with an increase of Ag NPs concentration. However, the addition of bovine serum albumin (BSA) could effectively alleviate the FO membrane fouling induced by Ag NPs. The interaction between Ag NPs and BSA was responsible for this phenomenon. BSA can easily form a nanoparticle-protein corona surrounded nanoparticles, which prevented nanoparticles from aggregation due to the steric stabilization mechanism. Furthermore, the interaction between BSA and Ag NPs occurred not only in wastewater but also on FO membrane surface. PMID:27160045

  12. NOx Control Options and Integration for US Coal Fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Mike Bockelie; Kevin Davis; Temi Linjewile; Connie Senior; Eric Eddings; Kevin Whitty; Larry Baxter; Calvin Bartholomew; William Hecker; Stan Harding; Robert Hurt

    2003-12-31

    This is the fourteenth Quarterly Technical Report for DOE Cooperative Agreement No: DEFC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. Using the initial CFD baseline modeling of the Gavin Station and the plant corrosion maps, six boiler locations for the corrosion probes were identified and access ports have been installed. Preliminary corrosion data obtained appear consistent and believable. In situ, spectroscopic experiments at BYU reported in part last quarter were completed. New reactor tubes have been made for BYU's CCR that allow for testing smaller amounts of catalyst and thus increasing space velocity; monolith catalysts have been cut and a small reactor that can accommodate these pieces for testing is in its final stages of construction. A poisoning study on Ca-poisoned catalysts was begun this quarter. A possible site for a biomass co-firing test of the slipstream reactor was visited this quarter. The slipstream reactor at Rockport required repair and refurbishment, and will be re-started in the next quarter. This report describes the final results of an experimental project at Brown University on the fundamentals of ammonia / fly ash interactions with relevance to the operation of advanced NOx control technologies such as selective catalytic reduction. The Brown task focused on the measurement of ammonia adsorption isotherms on commercial fly ash samples subjected to a variety of treatments and on the chemistry of dry and semi-dry ammonia removal processes.

  13. Potential applications of renewable energy sources, biomass combustion problems in boiler power systems and combustion related environmental issues

    International Nuclear Information System (INIS)

    This paper describes the potential applications of renewable energy sources to replace fossil fuel combustion as the prime energy sources in various countries, and discusses problems associated with biomass combustion in boiler power systems. Here, the term biomass includes organic matter produced as a result of photosynthesis as well as municipal, industrial and animal waste material. Brief summaries of the basic concepts involved in the combustion of biomass fuels are presented. Renewable energy sources (RES) supply 14% of the total world energy demand. RES are biomass, hydropower, geothermal, solar, wind and marine energies. The renewables are the primary, domestic and clean or inexhaustible energy resources. The percentage share of biomass was 62.1% of total renewable energy sources in 1995. Experimental results for a large variety of biomass fuels and conditions are presented. Numerical studies are also discussed. Biomass is an attractive renewable fuel in utility boilers. The compositions of biomass among fuel types are variable. Ash composition for the biomass is fundamentally different from ash composition for the coal. Especially inorganic constituents cause to critical problems of toxic emissions, fouling and slagging. Metals in ash, in combination with other fuel elements such as silica and sulfur, and facilitated by the presence of chlorine, are responsible for many undesirable reactions in combustion furnaces and power boilers. Elements including K, Na, S, Cl, P, Ca, Mg, Fe, Si are involved in reactions leading to ash fouling and slagging in biomass combustors. Chlorine in the biomass may affect operation by corrosion. Ash deposits reduce heat transfer and may also result in severe corrosion at high temperatures. Other influences of biomass composition are observed for the rates of combustion and pollutant emissions. Biomass combustion systems are non-polluting and offer significant protection of the environment. The reduction of greenhouse gases

  14. Neutron tubes

    Science.gov (United States)

    Leung, Ka-Ngo; Lou, Tak Pui; Reijonen, Jani

    2008-03-11

    A neutron tube or generator is based on a RF driven plasma ion source having a quartz or other chamber surrounded by an external RF antenna. A deuterium or mixed deuterium/tritium (or even just a tritium) plasma is generated in the chamber and D or D/T (or T) ions are extracted from the plasma. A neutron generating target is positioned so that the ion beam is incident thereon and loads the target. Incident ions cause D-D or D-T (or T-T) reactions which generate neutrons. Various embodiments differ primarily in size of the chamber and position and shape of the neutron generating target. Some neutron generators are small enough for implantation in the body. The target may be at the end of a catheter-like drift tube. The target may have a tapered or conical surface to increase target surface area.

  15. Straightening tubes

    International Nuclear Information System (INIS)

    Hexagonal wrapper tubes, especially for nuclear reactor core sub-assemblies, may suffer from unacceptable bow as a result of welding wear pads to the wrapper and heat treatment. Straightening of the bow is effected by a method wherein at each of a series of axially spaced locations the faces or vertices of the tube are measured relative to a reference to determine the direction of bow at the locations. From these measurements, the appropriate axial locations for the application of corrective loading can be determined, whereby by application of the loading at a selected face or vertex for such measurements the bow is reduced. Such loading, by an actuator, can be repeated at the locations until the bow is reduced to within tolerances. (author)

  16. Experimental Study on an On-Line Measurement of High Temperature Circulating Ash Flux in a Circulating Fluidized Bed Boiler

    Institute of Scientific and Technical Information of China (English)

    Lu Xiaofeng; Li Yourong

    2001-01-01

    A new kind of measuring method that may be used to measure high temperature circulating solid particles flux in a circulating fluidized bed boiler is studied in this paper. The measuring method is founded on the principle of thermal equilibrium. A series of cold tests and hot tests were carried to optimize the structure and collocation of water-cooling tubes and showed that the method had the advantage of simple, accurate, reliable and good applicability for on-line usage in a circulating fluidized bed boiler.

  17. 49 CFR 230.36 - Hydrostatic testing of boilers.

    Science.gov (United States)

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Pressure Testing of Boilers § 230.36 Hydrostatic testing of boilers. (a) Time of test. The... 49 Transportation 4 2010-10-01 2010-10-01 false Hydrostatic testing of boilers. 230.36 Section...

  18. 49 CFR 230.30 - Lap-joint seam boilers.

    Science.gov (United States)

    2010-10-01

    ..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Inspection and Repair § 230.30 Lap-joint seam boilers. Every boiler having lap-joint longitudinal seams... 49 Transportation 4 2010-10-01 2010-10-01 false Lap-joint seam boilers. 230.30 Section...

  19. 46 CFR 61.05-15 - Boiler mountings and attachments.

    Science.gov (United States)

    2010-10-01

    ... gauge for a boiler or a main steam line may be examined and checked for accuracy by the marine inspector... 46 Shipping 2 2010-10-01 2010-10-01 false Boiler mountings and attachments. 61.05-15 Section 61.05... TESTS AND INSPECTIONS Tests and Inspections of Boilers § 61.05-15 Boiler mountings and attachments....

  20. Foul Play in Sport as a Phenomenon Inconsistent with the Rules, yet Acceptable and Desirable: Ethical Conditions

    Directory of Open Access Journals (Sweden)

    Kosiewicz Jerzy

    2014-06-01

    Full Text Available The article has strictly a theoretical and non-empirical character. The author presents examples resulting from various observations. The aim of the paper is to present the causes, functions, and results of fouls, fouling, and foul play. Although fouls do not comply with the rules of games, the paper demonstrates that fouls are often used; they enjoy a quiet acceptance of the sporting world; they are tolerated and accepted; even more, they are often - more or less explicitly - desirable.

  1. Initial study of a method for IR measurements in boilers; Inledande studie av metod foer IR-maetning i aangpannor

    Energy Technology Data Exchange (ETDEWEB)

    Sandberg, Martin; Joensson, Magnus; Lundin, Leif [Swedish National Testing and Research Inst., Boraas (Sweden)

    1999-10-01

    The tubes in steam boilers are required to be regularly inspected, in order to find water-side deposits, thinning of walls or material defects. This is for safety, problem-free operation and high availability. No non-destructive method of inspection is available today for finding deposits on the insides of boiler tubes. Nor is there any method that can not only detect deposits on the insides of the tubes but also monitor the tubes' wall thicknesses. A suitable method - reliable, safe, easy to use and cost-efficient - is therefore needed. One such method is to measure the surface temperature of a larger area of the diaphragm wall, using a non-contact method, and from the resulting information to assess the material thickness and possible water-side or steam-side deposits. An IR camera is used for non-contact measurement of the radiated energy from several adjacent surface elements, and thus also of their temperature. The temperature is displayed on the camera's screen to produce a picture of the temperature distribution. This is a well-established method today, and is used in applications such as the steel industry, the electricity industry, electronics and health care. The surface temperatures of the tube walls can be measured by inserting an IR camera on an arm into the combustion chamber, without anyone having to get inside the boiler. The combustion chamber is the part of the boiler that is of main interest for inspection, as it is the easiest to reach. Measurements are facilitated by higher temperatures and thus higher heat fluxes through the tube walls. Diaphragm wall temperatures can be measured quickly and rationally over large areas. Points of interest in inspections include determining where there are water-side deposits in the tubes, where tubes are thin, where flow is obstructed and where there might be material defects. With the exception of material defects, all of these mechanisms result in changes in the surface temperature, which in many

  2. Electrical design requirements for electrode boilers for nuclear plants

    International Nuclear Information System (INIS)

    Medium-voltage steam electrode boilers, in the 20- to 50-MW range, have become an attractive alternative to comparable fossil-fueled boilers as a source of auxiliary steam during the startup and normal shutdown of nuclear power plants. The electrode boiler represents a favorable option because of environmental, fire protection, and licensing considerations. However, this electrical option brings some difficult design problems for which solutions are required in order to integrate the electrode boiler into the plant low resistance grounded power system. These considerations include the effects of an unbalanced electrode boiler on the performance of polyphase induction motors, boiler grounding for personnel safety, boiler neutral grounding, and ground relaying

  3. Boiler efficiency methodology for solar heat applications

    Science.gov (United States)

    Maples, D.; Conwell, J. C.; Pacheco, J. E.

    1992-08-01

    This report contains a summary of boiler efficiency measurements which can be applied to evaluate the performance of steam-generating boilers via both the direct and indirect methods. This methodology was written to assist industries in calculating the boiler efficiency for determining the applicability and value of thermal industrial heat, as part of the efforts of the Solar Thermal Design Assistance Center (STDAC) funded by Sandia National Laboratories. Tables of combustion efficiencies are enclosed as functions of stack temperatures and the amount of carbon dioxide and carbon monoxide in the gas stream.

  4. Chemical cleaning of UK AGR boilers

    International Nuclear Information System (INIS)

    For a number of years, the waterside pressure drops across the advanced gas-cooled reactor (AGR) pod boilers have been increasing. The pressure drop increases have accelerated with time, which is the converse behaviour to that expected for rippled magnetite formation (rapid initial increase slowing down with time). Nonetheless, magnetite deposition remains the most likely cause for the increasing boiler resistances. A number of potential countermeasures have been considered in response to the boiler pressure drop increases. However, there was no detectable reduction in the rate of pressure drop increase. Chemical cleaning was therefore considered and a project to substantiate and then implement chemical cleaning was initiated. (authors)

  5. Combustion of mediterranean agro-forest biomasses in small and medium scale pellet boilers: strategies for minimizing ash fusion and slagging

    Energy Technology Data Exchange (ETDEWEB)

    Vega-Nieva, Daniel J.; Dopazo, Raquel; Ortiz, Luis [Forest Engineering Univ. School. Univ. of Vigo, Pontevedra (Spain)], e-mail: DanielJVN@gmail.com

    2012-11-01

    The slagging and fouling risk remain as important barriers that are currently limiting the use of various agricultural residues and potential energy crops feedstocks (e.g. [1-3]), which remain largely unutilized, particularly in Mediterranean countries. In this oral communication, the main results from the VI Framework European Project Domoheat on the combustion of mediterranean biomasses and its mixtures on small and medium size domestic pellet boilers, are presented, together with the goals of the ongoing VII Framework European Project AshMelT focusing on the definition of objective criteria and tests for ash slagging in domestic pellet boilers. The utilization of ash slagging indices based on ash composition and the definition of biomass mixtures based on such ash indices are presented as potentially useful tools for minimizing the occurrence of ash fusion and slagging during combustion.

  6. Impact of effluent organic matter on low-pressure membrane fouling in tertiary treatment

    KAUST Repository

    Ayache, C.

    2013-05-01

    This study aims at comparing low-pressure membrane fouling obtained with two different secondary effluents at bench and pilot-scale based on the determination of two fouling indices: the total fouling index (TFI) and the hydraulically irreversible fouling index (HIFI). The main objective was to investigate if simpler and less costly bench-scale experimentation can substitute for pilot-scale trials when assessing the fouling potential of secondary effluent in large scale membrane filtration plants producing recycled water. Absolute values for specific flux and total fouling index for the bench-scale system were higher than those determined from pilot-scale, nevertheless a statistically significant correlation (r2 = 0.63, α = 0.1) was obtained for the total fouling index at both scales. On the contrary no such correlation was found for the hydraulically irreversible fouling index. Advanced water characterization tools such as excitation-emission matrix fluorescence spectroscopy (EEM) and liquid chromatography with organic carbon detection (LC-OCD) were used for the characterization of foulants. On the basis of statistical analysis, biopolymers and humic substances were found to be the major contribution to total fouling (r2 = 0.95 and r2 = 0.88, respectively). Adsorption of the low molecular weight neutral compounds to the membrane was attributed to hydraulically irreversible fouling (r2 = 0.67). © 2013 Elsevier Ltd.

  7. Robust Design Optimization Method for Centrifugal Impellers under Surface Roughness Uncertainties Due to Blade Fouling

    Institute of Scientific and Technical Information of China (English)

    JU Yaping; ZHANG Chuhua

    2016-01-01

    Blade fouling has been proved to be a great threat to compressor performance in operating stage. The current researches on fouling-induced performance degradations of centrifugal compressors are based mainly on simplified roughness models without taking into account the realistic factors such as spatial non-uniformity and randomness of the fouling-induced surface roughness. Moreover, little attention has been paid to the robust design optimization of centrifugal compressor impellers with considerations of blade fouling. In this paper, a multi-objective robust design optimization method is developed for centrifugal impellers under surface roughness uncertainties due to blade fouling. A three-dimensional surface roughness map is proposed to describe the nonuniformity and randomness of realistic fouling accumulations on blades. To lower computational cost in robust design optimization, the support vector regression (SVR) metamodel is combined with the Monte Carlo simulation (MCS) method to conduct the uncertainty analysis of fouled impeller performance. The analyzed results show that the critical fouled region associated with impeller performance degradations lies at the leading edge of blade tip. The SVR metamodel has been proved to be an efficient and accurate means in the detection of impeller performance variations caused by roughness uncertainties. After design optimization, the robust optimal design is found to be more efficient and less sensitive to fouling uncertainties while maintaining good impeller performance in the clean condition. This research proposes a systematic design optimization method for centrifugal compressors with considerations of blade fouling, providing a practical guidance to the design of advanced centrifugal compressors.

  8. Heat mass transfer model of fouling process of calcium carbonate on heat transfer surface

    Institute of Scientific and Technical Information of China (English)

    QUAN ZhenHua; CHEN YongChang; MA ChongFang

    2008-01-01

    A new heat mass transfer model was developed to predict the fouling process of calcium carbonate on heat transfer surface.The model took into account not only the crystallization fouling but also the particle fouling which was formed on the heat transfer surface by the suspension particles of calcium carbonate in the su-persaturated solution.Based on experimental results of the fouling process,the deposition and removal rates of the mixing fouling were expressed.Furthermore,the coupling effect of temperature with the fouling process was considered in the physics model.As a result the fouling resistance varying with time was obtained to describe the fouling process and the prediction was compared with experimental data under same conditions.The results showed that the present model could give a good prediction of fouling process,and the deviation was less than 15% of the experimental data in most cases.The new model is credible to predict the fouling process.

  9. Biomimetic characterisation of key surface parameters for the development of fouling resistant materials.

    Science.gov (United States)

    Scardino, A J; Hudleston, D; Peng, Z; Paul, N A; de Nys, R

    2009-01-01

    Material science provides a direct route to developing a new generation of non-toxic, surface effect-based antifouling technologies with applications ranging from biomedical science to marine transport. The surface topography of materials directly affects fouling resistance and fouling removal, the two key mechanisms for antifouling technologies. However, the field is hindered by the lack of quantified surface characteristics to guide the development of new antifouling materials. Using a biomimetic approach, key surface parameters are defined and quantified and correlated with fouling resistance and fouling removal from the shells of marine molluscs. Laser scanning confocal microscopy was used to acquire images for quantitative surface characterisation using three-dimensional surface parameters, and field assays correlated these with fouling resistance and fouling release. Principle component analysis produced a major component (explaining 54% of total variation between shell surfaces) that correlated with fouling resistance. The five surface parameters positively correlated to increased fouling resistance were, in order of importance, low fractal dimension, high skewness of both the roughness and waviness profiles, higher values of isotropy and lower values of mean surface roughness. The second component (accounting for 20% of variation between shells) positively correlated to fouling release, for which higher values of mean waviness almost exclusively dictated this relationship. This study provides quantified surface parameters to guide the development of new materials with surface properties that confer fouling resistance and release.

  10. Robust design optimization method for centrifugal impellers under surface roughness uncertainties due to blade fouling

    Science.gov (United States)

    Ju, Yaping; Zhang, Chuhua

    2016-03-01

    Blade fouling has been proved to be a great threat to compressor performance in operating stage. The current researches on fouling-induced performance degradations of centrifugal compressors are based mainly on simplified roughness models without taking into account the realistic factors such as spatial non-uniformity and randomness of the fouling-induced surface roughness. Moreover, little attention has been paid to the robust design optimization of centrifugal compressor impellers with considerations of blade fouling. In this paper, a multi-objective robust design optimization method is developed for centrifugal impellers under surface roughness uncertainties due to blade fouling. A three-dimensional surface roughness map is proposed to describe the nonuniformity and randomness of realistic fouling accumulations on blades. To lower computational cost in robust design optimization, the support vector regression (SVR) metamodel is combined with the Monte Carlo simulation (MCS) method to conduct the uncertainty analysis of fouled impeller performance. The analyzed results show that the critical fouled region associated with impeller performance degradations lies at the leading edge of blade tip. The SVR metamodel has been proved to be an efficient and accurate means in the detection of impeller performance variations caused by roughness uncertainties. After design optimization, the robust optimal design is found to be more efficient and less sensitive to fouling uncertainties while maintaining good impeller performance in the clean condition. This research proposes a systematic design optimization method for centrifugal compressors with considerations of blade fouling, providing a practical guidance to the design of advanced centrifugal compressors.

  11. Membrane fouling in pilot-scale membrane bioreactors (MBRs) treating municipal wastewater.

    Science.gov (United States)

    Kimura, Katsuki; Yamato, Nobuhiro; Yamamura, Hiroshi; Watanabe, Yoshimasa

    2005-08-15

    The main obstacle for wider use of membrane bioreactors (MBRs) for wastewater treatment is membrane fouling (i.e., deterioration of membrane permeability),which increases operating costs. For more efficient control of membrane fouling in MBRs, an understanding of the mechanisms of membrane fouling is important. However, there is a lack of information on membrane fouling in MBRs, especially information on features of components that are responsible for the fouling. We conducted a pilot-scale experiment using real municipal wastewater with three identical MBRs under different operating conditions. The results obtained in this study suggested that the food-microorganisms ratio (F/M) and membrane filtration flux were the important operating parameters that significantly influenced membrane fouling in MBRs. Neither concentrations of dissolved organic matter in the reactors nor viscosity of mixed liquor, which have been thought to have influences on fouling in MBRs, showed clear relationships with membrane fouling in this study. Organic substances that had caused the membrane fouling were desorbed from fouled membranes of the MBRs at the termination of the operation and were subjected to Fourier transform infrared (FTIR) and 13C nuclear magnetic resonance (NMR) analyses. These analyses revealed that the nature of the membrane foulant changes depending on F/M. It was shown that high F/M would make the foulant more proteinaceous. Carbohydrates were dominant in membrane foulants in this study, while features of humic substances were not apparent.

  12. Contribution of effluent organic matter (EfOM) to ultrafiltration (UF) membrane fouling: Isolation, characterization, and fouling effect of EfOM fractions

    KAUST Repository

    Zheng, Xing

    2014-11-01

    EfOM has been regarded as a major organic foulant resulting in UF membrane fouling in wastewater reclamation. To investigate fouling potential of different EfOM fractions, the present study isolated EfOM into hydrophobic neutrals (HPO-N), colloids, hydrophobic acids (HPO-A), transphilic neutrals and acids (TPI), and hydrophilics (HPI), and tested their fouling effect in both salt solution and pure water during ultrafiltration (UF). Major functional groups and chemical structure of the isolates were identified using Fourier transform infrared spectroscopy (FT-IR) and solid-state carbon nuclear magnetic resonance (13C NMR) analysis. The influence of the isolation process on the properties of EfOM fractions was minor because the raw and reconstituted secondary effluents were found similar with respect to UV absorbance, molecular size distribution, and fluorescence character. In membrane filtration tests, unified membrane fouling index (UMFI) and hydraulic resistance were used to quantify irreversible fouling potential of different water samples. Results show that under similar DOC level in feed water, colloids present much more irreversible fouling than other fractions. The fouling effect of the isolates is related to their size, chemical properties, and solution chemistry. Further investigations have identified that the interaction between colloids and other fractions also influences the performance of colloids in fouling phenomena. © 2014 Elsevier Ltd.

  13. Heat Transfer Studies in Tube Banks with Integral Wake Splitters

    Directory of Open Access Journals (Sweden)

    Suzairin Md Seri

    2009-09-01

    Full Text Available This paper reports the findings from heat transfer studies with the presence of extended surfaces from tube banks which are termed as integral wake splitter plates. Employing this type of fins, investigations on heat transfer characteristics on a single circular tube as well as tube banks were carried out in cross flow of air in a rectangular duct. Experiments were carried out in the Reynolds number range 5 x 103 to 105 on a single cylinder of various splitter length-to-tube diameter ratios, L/D = 0.5, 1.0, 1.5 and 2.0. Further, tube banks consisting of 12 rows and 3 tubes per row in equilateral triangle arrangements with transverse pitch to diameter ratio, a = 2, were also investigated, the banks being made up of plain tubes or tubes with splitters. Heat transfer characteristics were studied for tubes with L/D = 0, 0.5 and 1.0 under constant heat flux conditions. Tube banks with L/D = 1.0 yielded the highest heat transfer rates. Findings from this work may be adopted to be utilized in various industrial applications such as economizer of a steam boiler, air-conditioning coils or waste heat recovery systems.

  14. Reduced Bed Temperature in FB-Boilers Burning Waste - part II; Saenkt baeddtemperatur i FB-pannor foer avfallsfoerbraenning - etapp 2

    Energy Technology Data Exchange (ETDEWEB)

    Niklasson, Fredrik; Pettersson, Anita; Claesson, Frida; Johansson, Andreas; Gunnarsson, Anders; Gyllenhammar, Marianne; Victoren, Anders; Gustafsson, Goeran

    2010-07-01

    This project focuses on evaluating whether lowered bed temperature in FB-boilers for waste combustion gives operational benefits, such as reduced fouling in the convection pass. If so, this mode of operation could reduce the number of unplanned boiler outages, reduce the need for soot blowing, and extend the lifetime of the superheaters at unaltered steam temperature. The project is based on full-scale experiments performed at Ryaverket in Boraas. The plant has two waste-fired 20 MW{sub t} FB-boilers. The study is based on a comparison between operational data and measurement results from two different operating conditions of the boilers. In addition to the data that normally are logged by the control system, samples of fuel, ashes, particles, and deposits were taken and subsequently analyzed. The structure of the bed ash was altered by lowering the bed temperature. Under normal boiler operation, the bed ash contains many small agglomerates that disappeared when the bed temperature was lowered. Due to this, the sand consumption of the plant could be reduced by roughly 25 %. At lowered bed temperature, the concentration of chlorine increased in the bed ash and in the recycled sand while it decreased in the ashes from the cyclone and fabric filter. The concentration of HCl in the flue gas increased as the bed temperature was lowered. This is considered a consequence of less chlorine forming alkali chlorides. Moreover, the particle measurements showed that the amount of submicron particles decreased during lowered bed temperature, which also is an indication of less alkali chlorides in the flue gas. The deposit probes showed an approximate 20 % reduction of the fouling rate when the bed temperature was lowered from 876 to 714 deg C. The chlorine content also decreased in the deposits. For the deposit probes at 500 deg C, (corresponds to a steam temperature of 465 deg C) significant amounts of KCl were found in the deposits, even when the bed temperature was lowered

  15. Worldwide genetic differentiation in the common fouling barnacle, Amphibalanus amphitrite

    KAUST Repository

    Chen, Hsi-Nien

    2014-10-21

    © 2014, © 2014 Taylor & Francis. Amphibalanus amphitrite is a common fouling barnacle distributed globally in tropical and subtropical waters. In the present study, the genetic (mitochondrial cytochrome oxidase subunit I) and morphological differentiation in A. amphitrite from 25 localities around the world were investigated. The results revealed three clades within A. amphitrite with a genetic divergence of ~ 4% among clades, whereas there were no diagnostic morphological differences among clades. Clade 1 is widely distributed in both temperate and tropical waters, whereas Clade 3 is currently restricted to the tropical region. The deep divergence among clades suggests historical isolation within A. amphitrite; thus, the present geographical overlaps are possibly a result of the combined effects of rising sea level and human-mediated dispersals. This study highlights the genetic differentiation that exists in a common, widely distributed fouling organism with great dispersal potential; future antifouling research should take into account the choice of lineages.

  16. photomultiplier tubes

    CERN Multimedia

    photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  17. photomultiplier tube

    CERN Multimedia

    photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  18. Tube furnace

    Science.gov (United States)

    Foster, Kenneth G.; Frohwein, Eugene J.; Taylor, Robert W.; Bowen, David W.

    1991-01-01

    A vermiculite insulated tube furnace is heated by a helically-wound resistance wire positioned within a helical groove on the surface of a ceramic cylinder, that in turn is surroundingly disposed about a doubly slotted stainless steel cylindrical liner. For uniform heating, the pitch of the helix is of shorter length over the two end portions of the ceramic cylinder. The furnace is of large volume, provides uniform temperature, offers an extremely precise programmed heating capability, features very rapid cool-down, and has a modest electrical power requirement.

  19. Failure of Titanium Condenser Tubes after 24 Years Power Plant Service

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Enemark, Allan; Hangaard, Anders

    2014-01-01

    The titanium condenser has been in operation for 24 years at Amager unit 3 power plant. In February 2012, the plant was contaminated by seawater due to a failed condenser tube and some tubes were plugged. A month later, the plant tripped again. Small leaks were found again and finally approx. 200...... tubes were plugged before the condenser was in service again. A series of inspections, NDT, and destructive examinations were conducted to try and understand the cause of failure in the tubes within the condenser. After such investigations, degradation mechanisms such as inner fouling, steam impingement......, and fretting/erosion around the supports could be discounted. Ductile cracks were found in the tube within the tubesheet. From circumstantial evidence, it was concluded that failure was caused by a semi-filled condenser which led to a mismatch in expansion coefficients of filled tubes and unfilled...

  20. Liquid infused porous surfaces for mineral fouling mitigation.

    Science.gov (United States)

    Charpentier, Thibaut V J; Neville, Anne; Baudin, Sophie; Smith, Margaret J; Euvrard, Myriam; Bell, Ashley; Wang, Chun; Barker, Richard

    2015-04-15

    Prevention of mineral fouling, known as scale, is a long-standing problem in a wide variety of industrial applications, such as oil production, water treatment, and many others. The build-up of inorganic scale such as calcium carbonate on surfaces and facilities is undesirable as it can result in safety risks and associated flow assurance issues. To date the overwhelming amount of research has mainly focused on chemical inhibition of scale bulk precipitation and little attention has been paid to deposition onto surfaces. The development of novel more environmentally-friendly strategies to control mineral fouling will most probably necessitate a multifunctional approach including surface engineering. In this study, we demonstrate that liquid infused porous surfaces provide an appealing strategy for surface modification to reduce mineral scale deposition. Microporous polypyrrole (PPy) coatings were fabricated onto stainless steel substrates by electrodeposition in potentiostatic mode. Subsequent infusion of low surface energy lubricants (fluorinated oil Fluorinert FC-70 and ionic liquid 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIm)) into the porous coatings results in liquid-repellent slippery surfaces. To assess their ability to reduce surface scaling the coatings were subjected to a calcium carbonate scaling environment and the scale on the surface was quantified using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). PPy surfaces infused with BMIm (and Fluorinert to a lesser extent) exhibit remarkable antifouling properties with the calcium carbonate deposition reduced by 18 times in comparison to untreated stainless steel. These scaling tests suggest a correlation between the stability of the liquid infused surfaces in artificial brines and fouling reduction efficiency. The current work shows the great potential of such novel coatings for the management of mineral scale fouling. PMID:25585291