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Sample records for recovery boiler modeling

  1. Recovery boiler model; Soodakattilan kehitystyoe III

    Energy Technology Data Exchange (ETDEWEB)

    Janka, K.; Ylitalo, M.; Sundstroem, K.; Helke, R.; Heinola, M. [Kvaerner Pulping Oy, Tampere (Finland)

    1997-10-01

    The recovery boiler model was further tested and developed. At this moment the model includes submodels for: droplet drying, pyrolysis, char burning, gas burning and for droplet trajectory. During 1996 the formation of CH{sub 4} during pyrolysis and release of sulfur was included to the model. Further the formation of NO from fuel nitrogen and formation of thermal- NO were included to the model using Arrhenius type reaction rate equations. The calculated results are realistic and the model is used as a tool to find out methods to increase the efficiency and availability and decrease the emissions. Analysing the results of the earlier field study of 8 boilers showed that the furnace heat load, fuming rate, find the black liquor composition have influence on the enrichment of the potassium to the fly ash. (orig.)

  2. 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)

  3. 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.

  4. 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

  5. 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)

    1997-12-31

    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

  6. 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.

  7. Cracking and corrosion recovery boiler

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-12-31

    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.

  8. 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.)

  9. MODELLING, SIMULATING AND OPTIMIZING BOILERS

    DEFF Research Database (Denmark)

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

    2004-01-01

    In the present work a framework for optimizing the design of boilers for dynamic operation has been developed. A cost function to be minimized during the optimization has been formulated and for the present design variables related to the Boiler Volume and the Boiler load Gradient (i.e. ring rate...... on the boiler) have been dened. Furthermore a number of constraints related to: minimum and maximum boiler load gradient, minimum boiler size, Shrinking and Swelling and Steam Space Load have been dened. For dening the constraints related to the required boiler volume a dynamic model for simulating the boiler...... performance has been developed. Outputs from the simulations are shrinking and swelling of water level in the drum during for example a start-up of the boiler, these gures combined with the requirements with respect to allowable water level uctuations in the drum denes the requirements with respect to drum...

  10. Hybrid model of steam boiler

    International Nuclear Information System (INIS)

    Rusinowski, Henryk; Stanek, Wojciech

    2010-01-01

    In the case of big energy boilers energy efficiency is usually determined with the application of the indirect method. Flue gas losses and unburnt combustible losses have a significant influence on the boiler's efficiency. To estimate these losses the knowledge of the operating parameters influence on the flue gases temperature and the content of combustible particles in the solid combustion products is necessary. A hybrid model of a boiler developed with the application of both analytical modelling and artificial intelligence is described. The analytical part of the model includes the balance equations. The empirical models express the dependence of the flue gas temperature and the mass fraction of the unburnt combustibles in solid combustion products on the operating parameters of a boiler. The empirical models have been worked out by means of neural and regression modelling.

  11. Feasibility of recovery boiler in paper and pulp industry

    International Nuclear Information System (INIS)

    Rashid, H.

    2010-01-01

    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)

  12. Factors controlling alkalisalt deposition in recovery boiler- release mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    McKeough, P.; Kylloenen, H.; Kurkela, M. [VTT Energy, Espoo (Finland). Process Technology Group

    1996-12-01

    As part of a cooperative effort to develop a model to describe the behaviour of inorganic compounds in kraft recovery boilers, an experimental investigation of the release of sulphur during black liquor pyrolysis has been undertaken. Previous to these studies, the mechanisms of sulphur release and the reasons for the observed effects of process conditions on sulphur release were very poorly understood. On the basis of the experimental results, the main reactions leading to sulphur release have been elucidated with a fair degree of certainty. Logical explanations for the variations of sulphur release with temperature and with liquor solids content have been proposed. The influence of pressure has been investigated in order to gain insights into the effects of mass transfer on the sulphur-release rate. In the near future, the research will be aimed at generating the kinetic data necessary for modelling the release of sulphur in the recovery furnace. (author)

  13. Structured Mathematical Modeling of Industrial Boiler

    Directory of Open Access Journals (Sweden)

    Abdullah Nur Aziz

    2014-04-01

    Full Text Available As a major utility system in industry, boilers consume a large portion of the total energy and costs. Significant reduction of boiler cost operation can be gained through improvements in efficiency. In accomplishing such a goal, an adequate dynamic model that comprehensively reflects boiler characteristics is required. This paper outlines the idea of developing a mathematical model of a water-tube industrial boiler based on first principles guided by the bond graph method in its derivation. The model describes the temperature dynamics of the boiler subsystems such as economizer, steam drum, desuperheater, and superheater. The mathematical model was examined using industrial boiler performance test data.It can be used to build a boiler simulator or help operators run a boiler effectively.

  14. Structured Mathematical Modeling of Industrial Boiler

    OpenAIRE

    Aziz, Abdullah Nur; Nazaruddin, Yul Yunazwin; Siregar, Parsaulian; Bindar, Yazid

    2014-01-01

    As a major utility system in industry, boilers consume a large portion of the total energy and costs. Significant reduction of boiler cost operation can be gained through improvements in efficiency. In accomplishing such a goal, an adequate dynamic model that comprehensively reflects boiler characteristics is required. This paper outlines the idea of developing a mathematical model of a water-tube industrial boiler based on first principles guided by the bond graph method in its derivation. T...

  15. New configurations of a heat recovery absorption heat pump integrated with a natural gas boiler for boiler efficiency improvement

    International Nuclear Information System (INIS)

    Qu, Ming; Abdelaziz, Omar; Yin, Hongxi

    2014-01-01

    Highlights: • Thermal and heat transfer models of absorption heat pumps driven by exhaust gas, hot water, or natural gas. • Natural gas boiler combustion model. • Heat exchanger for condensing. • Experimental data of a hot water absorption heat pump. • Economic assessment of heat recovery absorption heat pump for improving natural gas boilers. - Abstract: Conventional natural gas-fired boilers exhaust flue gas direct to the atmosphere at 150–200 °C, which, at such temperatures, contains large amount of energy and results in relatively low thermal efficiency ranging from 70% to 80%. Although condensing boilers for recovering the heat in the flue gas have been developed over the past 40 years, their present market share is still less than 25%. The major reason for this relatively slow acceptance is the limited improvement in the thermal efficiency of condensing boilers. In the condensing boiler, the temperature of the hot water return at the range of 50–60 °C, which is used to cool the flue gas, is very close to the dew point of the water vapor in the flue gas. Therefore, the latent heat, the majority of the waste heat in the flue gas, which is contained in the water vapor, cannot be recovered. This paper presents a new approach to improve boiler thermal efficiency by integrating absorption heat pumps with natural gas boilers for waste heat recovery (HRAHP). Three configurations of HRAHPs are introduced and discussed. The three configurations are modeled in detail to illustrate the significant thermal efficiency improvement they attain. Further, for conceptual proof and validation, an existing hot water-driven absorption chiller is operated as a heat pump at operating conditions similar to one of the devised configurations. An overall system performance and economic analysis are provided for decision-making and as evidence of the potential benefits. These three configurations of HRAHP provide a pathway to achieving realistic high-efficiency natural

  16. Factors controlling alkali salt deposition in recovery boilers. Release mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    McKeough, P; Kurkela, M; Kylloenen, H; Tapola, E [VTT Energy, Espoo (Finland). Process Technology Group

    1997-10-01

    The research was part of an ongoing cooperative research effort aimed at developing a model to describe the behaviour of inorganic compounds in kraft recovery boilers. During 1996 experimental investigations of sulphur release were continued. Experiments at elevated pressures and employing larger particle sizes were performed in order to gain information about mass transfer effects. The first experiments yielding data on the rates of the sulphur-release reactions were performed. This data will be used as the basis of a drop model for sulphur release being developed in cooperation with another research group. The other part of the work during 1996 explored the possibility of using chemical equilibrium calculations to predict the release of sodium, potassium and chlorine in the recovery furnace. The approach is essentially different from that employed in earlier studies in that the effects of fume formation are taken into account. So far, the predictions of the chemical equilibrium release model have, in no way, conflicted with field measurements. (orig.)

  17. MODELLING, SIMULATING AND OPTIMIZING BOILERS

    DEFF Research Database (Denmark)

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

    2003-01-01

    , 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...... freedom with respect to dynamic operation of the plant. By means of an objective function including as well the price of the plant as a quantification of the value of dynamic operation of the plant an optimization is carried out. The dynamic model of the boiler plant is applied to define parts...

  18. Studies Concerning Water-Surface Deposits in Recovery Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Strandberg, O; Arvesen, J; Dahl, L

    1971-11-15

    The Feed-water Committee of the Stiftelsen Svensk Cellulosaforskning (Foundation for Swedish Cellulose Research) has initiated research and investigations which aim to increase knowledge about water-surface deposits in boiler tubes, and the resulting risks of gas-surface corrosion in chemical recovery boilers (sulphate pulp industry). The Committee has arranged with AB Atomenergi, Studsvik, for investigations into the water-surface deposits on tubes from six Scandinavian boilers. These investigations have included direct measurements of the thermal conductivity of the deposits, and determinations of their quantity, thickness and structure have been carried out. Previous investigations have shown that gas-surface corrosion can occur at tube temperatures above 330 deg C. The measured values for the thermal conductivity of the deposits indicate that even with small quantities of deposit (c. 1 g/dm2 ) and a moderate boiler pressure (40 atm), certain types of deposit can give rise to the above-mentioned surface temperature, at which the risk of gas-surface corrosion becomes appreciable. For higher boiler pressures the risk is great even with a minimal layer of deposit. The critical deposit thickness can be as low as 0.1 mm

  19. 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.

  20. Exergy analysis and evolutionary optimization of boiler blowdown heat recovery in steam power plants

    International Nuclear Information System (INIS)

    Vandani, Amin Mohammadi Khoshkar; Bidi, Mokhtar; Ahmadi, Fatemeh

    2015-01-01

    Highlights: • Heat recovery of boiler blow downed water using a flash tank is modeled. • Exergy destruction of each component is calculated. • Exergy efficiency of the whole system is optimized using GA and PSO algorithms. • Utilizing the flash tank increases the net power and efficiency of the system. - Abstract: In this study, energy and exergy analyses of boiler blowdown heat recovery are performed. To evaluate the effect of heat recovery on the system performance, a steam power plant in Iran is selected and the results of implementation of heat recovery system on the power plant are investigated. Also two different optimization algorithms including GA and PSO are established to increase the plant efficiency. The decision variables are extraction pressure from steam turbine and temperature and pressure of boiler outlet stream. The results indicate that using blowdown recovery technique, the net generated power increases 0.72%. Also energy and exergy efficiency of the system increase by 0.23 and 0.22, respectively. The optimization results show that temperature and pressure of boiler outlet stream have a higher effect on the exergy efficiency of the system in respect to the other decision variables. Using optimization methods, exergy efficiency of the system reaches to 30.66% which shows a 1.86% augmentation with regard to the situation when a flash tank is implemented.

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

    Science.gov (United States)

    Kychakoff, George [Maple Valley, WA; Afromowitz, Martin A [Mercer Island, WA; Hogle, Richard E [Olympia, WA

    2008-10-14

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

  2. 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....

  3. Soot blowing methods and soot steam consumption in Swedish recovery boilers; Sotningsmetoder och sotaangfoerbrukning i svenska sodapannor

    Energy Technology Data Exchange (ETDEWEB)

    Svedin, Kristoffer; Wallin, Erik; Ahlroth, Mikael

    2008-09-15

    The aim with the report was to put together a description of the current state of the sootblowing systems at Swedish recovery boilers, and to explain differences in cleanability and sootblowing efficiency. In chapter 4 a summary of new techniques and alternative soot blowing methods is found. The report is intended for persons working in the pulp industry. To facilitate the benchmarking the recovery boilers have been divided into two groups. Group A comprises recovery boilers which only have one stop per year and the remaining recovery boilers with more than one stop are classified into group B. The following conclusions, based on the recovery boiler design specifications, are of importance to achieve high boiler availability: Low furnace load; High recovery boiler, wide furnace bottom area; Modern air ports; Small or no correlation between cross pitch division in heat surfaces and cleanability could be seen. The expectation was to identify such a relation. However there are doubts on the correctness in reported data. The amount of chlorine and potassium is assumed to affect the cleanability for a few recovery boilers, but for the majority the amounts are low and most likely do not impact the operation. Because of the large impact of the recovery boilers design data (furnace area, load etc.) on the sootblowing, it has been hard to identify the relation cleanability contra sootblowing system. The relations that could be seen are: No distinction between normally designed nozzles and 'high efficiency' nozzles could be identified. The operational conditions for the different models differ a lot and the effect of nozzle type could not be distinguished. Only a minority of the soot blowing sequences are known from the study. In the recovery boilers with problematic areas improvements can be made in the soot blowing sequence. Four recovery boilers are using intelligent soot blowing of some kind. Two of these boilers have low availability and the other two have

  4. MSWI boiler fly ashes: magnetic separation for material recovery.

    Science.gov (United States)

    De Boom, Aurore; Degrez, Marc; Hubaux, Paul; Lucion, Christian

    2011-07-01

    Nowadays, ferrous materials are usually recovered from Municipal Solid Waste Incineration (MSWI) bottom ash by magnetic separation. To our knowledge, such a physical technique has not been applied so far to other MSWI residues. This study focuses thus on the applicability of magnetic separation on boiler fly ashes (BFA). Different types of magnet are used to extract the magnetic particles. We investigate the magnetic particle composition, as well as their leaching behaviour (EN 12457-1 leaching test). The magnetic particles present higher Cr, Fe, Mn and Ni concentration than the non-magnetic (NM) fraction. Magnetic separation does not improve the leachability of the NM fraction. To approximate industrial conditions, magnetic separation is also applied to BFA mixed with water by using a pilot. BFA magnetic separation is economically evaluated. This study globally shows that it is possible to extract some magnetic particles from MSWI boiler fly ashes. However, the magnetic particles only represent from 23 to 120 g/kg of the BFA and, though they are enriched in Fe, are composed of similar elements to the raw ashes. The industrial application of magnetic separation would only be profitable if large amounts of ashes were treated (more than 15 kt/y), and the process should be ideally completed by other recovery methods or advanced treatments. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Improved Materials for Use as Components in Kraft Black Liquor Recovery Boilers; TOPICAL

    International Nuclear Information System (INIS)

    Keiser, J.R.

    2001-01-01

    This Cooperative Research and Development Agreement (CRADA) was undertaken to evaluate current and improved materials and materials processing conditions for use as components in kraft black liquor recovery boilers and other unit processes. The main areas addressed were: (1) Improved Black Liquor Nozzles, (2) Weld Overlay of Composite Floor Tubes, and (3) Materials for Lime Kilns. Iron aluminide was evaluated as an alternate material for the nozzles used to inject an aqueous solution known as black liquor into recovery boilers as well for the uncooled lining in the ports used for the nozzles. Although iron aluminide is known to have much better sulfidation resistance in gases than low alloy and stainless steels, it did not perform adequately in the environment where it came into contact with molten carbonate, sulfide and sulfate salts. Weld overlaying carbon steel tubes with a layer of stainless weld metal was a proposed method of extending the life of recovery boiler floor tubes that have experienced considerable fireside corrosion. After exposure under service conditions, sections of weld overlaid floor tubes were removed from a boiler floor and examined metallographically. Examination results indicated satisfactory performance of the tubes. Refractory-lined lime kilns are a critical component of the recovery process in kraft pulp mills, and the integrity of the lining is essential to the successful operation of the kiln. A modeling study was performed to determine the cause of, and possible solutions for, the repeated loss of the refractory lining from the cooled end of a particular kiln. The evaluation showed that the temperature, the brick shape and the coefficient of friction between the bricks were the most important parameters influencing the behavior of the refractory lining

  6. Evaluation of trigeneration system using microturbine, ammonia-water absorption chiller, and a heat recovery boiler

    Energy Technology Data Exchange (ETDEWEB)

    Preter, Felipe C.; Rocha, Marcelo S.; Simoes-Moreira, Jose Roberto [SISEA - Alternative Energy Systems Lab. Dept. of Mechanical Engineering. University of Sao Paulo (EP/USP), SP (Brazil)], e-mails: felipe.preter@poli.usp.br, msrocha@poli.usp.br, jrsimoes@usp.br; Andreos, Ronaldo [COMGAS - Companhia de Gas de Sao Paulo, SP (Brazil)], e-mail: randreos@comgas.com.br

    2010-07-01

    In this work, a CCHP or tri generation system has been projected, mounted, and tested in laboratory, combining a microturbine for power generation, a heat recovery boiler for hot water production, and an ammonia water absorption chiller for chilled water production. The project was motivated by the large practical applications of this kind of energy recovery system in commerce, and industry, and, in general, more than 85% of the energy source is used as power, hot water, and cold water. In the first part, the trigeneration system theoretical model is detailed, and in the second part, experimental results are presented for different operation conditions. (author)

  7. Electrostatic precipitator performance and trace element emissions from two Kraft recovery boilers.

    Science.gov (United States)

    Lind, Terttaliisa; Hokkinen, Jouni; Jokiniemi, Jorma K; Hillamo, Risto; Makkonen, Ulla; Raukola, Antti; Rintanen, Jaakko; Saviharju, Kari

    2006-01-15

    Fine particle emissions from combustion sources have gained attention recently due to their adverse effects on human health. The emission depends on the combustion process, fuel, and particulate removal technology. Particle concentrations at Kraft recovery boiler exits are very high, and the boilers are typically equipped with electrostatic precipitators (ESP). However, little data are available on the ESP performance in recovery boilers. Particle concentrations and size distributions were determined at two modern, operating recovery boilers. In addition, we determined the fractional collection efficiency of the ESPs by simultaneous measurements at the ESP inlet and outlet and the particulate emissions of trace metals. The particle mass concentration atthe ESP inlet was 11-24 g/Nm3 at the two boilers. Particle emissions were 30-40 mg/ Nm3 at boiler A and 12-15 mg/Nm3 at boiler B. The particle size distributions had a major particle mode at around 1 microm. These fume particles contained most of the particle mass. The main components in the particles were sodium and sulfate with minor amounts of chloride, potassium, and presumably some carbonate. The ESP collection efficiency was 99.6-99.8% at boiler A and 99.9% at boiler B. The particle penetration through the ESP was below 0.6% in the entire fume particle size range of 0.3-3 microm. Trace element emissions from both boilers were well below the limit values set by EU directive for waste incineration.

  8. Direct recovery of boiler residue by combustion synthesis.

    Science.gov (United States)

    Nourbaghaee, Homan; Ghaderi Hamidi, Ahmad; Pourabdoli, Mahdi

    2018-04-01

    Boiler residue (BR) of thermal power plants is one of the important secondary sources for vanadium production. In this research, the aluminothermic self-propagating high-temperature synthesis (SHS) was used for recovering the transition metals of BR for the first time. The effects of extra aluminum as reducing agent and flux to aluminum ratio (CaO/Al) were studied and the efficiency of recovery and presence of impurities were measured. Aluminothermic reduction of vanadium and other metals was carried out successfully by SHS without any foreign heat source. Vanadium, iron, and nickel principally were reduced and gone into metallic master alloy as SHS product. High levels of efficiency (>80%) were achieved and the results showed that SHS has a great potential to be an industrial process for BR recovery. SHS produced two useful products. Metallic master alloy and fused glass slag that is applicable for ceramic industries. SHS can also neutralize the environmental threats of BR by a one step process. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Reduction efficiency prediction of CENIBRA's recovery boiler by direct minimization of gibbs free energy

    Directory of Open Access Journals (Sweden)

    W. L. Silva

    2008-09-01

    Full Text Available The reduction efficiency is an important variable during the black liquor burning process in the Kraft recovery boiler. This variable value is obtained by slow experimental routines and the delay of this measure disturbs the pulp and paper industry customary control. This paper describes an optimization approach for the reduction efficiency determination in the furnace bottom of the recovery boiler based on the minimization of the Gibbs free energy. The industrial data used in this study were directly obtained from CENIBRA's data acquisition system. The resulting approach is able to predict the steady state behavior of the chemical composition of the furnace recovery boiler, - especially the reduction efficiency when different operational conditions are used. This result confirms the potential of this approach in the analysis of the daily operation of the recovery boiler.

  10. Model boiler studies on deposition and corrosion

    International Nuclear Information System (INIS)

    Balakrishnan, P.V.; McVey, E.G.

    1977-09-01

    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)

  11. CCD camera eases the control of a soda recovery boiler; CCD-kamera helpottaa soodakattilan valvontaa

    Energy Technology Data Exchange (ETDEWEB)

    Kinnunen, L.

    2001-07-01

    Fortum Technology has developed a CCD firebox camera, based on semiconductor technology, enduring hard conditions of soda recovery boiler longer than traditional cameras. The firebox camera air- cooled and the same air is pressed over the main lens so it remains clean despite of the alkaline liquor splashing around in the boiler. The image of the boiler is transferred through the main lens, image transfer lens and a special filter, mounted inside the camera tube, into the CCD camera. The first CCD camera system has been in use since 1999 in Sunila pulp mill in Kotka, owned by Myllykoski Oy and Enso Oyj. The mill has two medium-sized soda recovery boilers. The amount of black liquor, formed daily, is about 2000 tons DS, which is more than enough for the heat generation. Even electric power generation exceeds sometimes the demand, so the surplus power can be sold out. Black liquor is sprayed inside the soda recovery boiler with high pressure. The liquor form droplets in the boiler, the temperature of which is over 1000 deg C. A full-hot pile is formed at the bottom of the boiler after burning. The size and shape of the pile effect on the efficiency and the emissions of the boiler. The camera has operated well.

  12. Improved Recovery Boiler Performance Through Control of Combustion, Sulfur, and Alkali Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Larry L.

    2008-06-09

    This project involved the following objectives: 1. Determine black liquor drying and devolatilization elemental and total mass release rates and yields. 2. Develop a public domain physical/chemical kinetic model of black liquor drop combustion, including new information on drying and devolatilization. 3. Determine mechanisms and rates of sulfur scavenging in recover boilers. 4. Develop non-ideal, public-domain thermochemistry models for alkali salts appropriate for recovery boilers 5. Develop data and a one-dimensional model of a char bed in a recovery boiler. 6. Implement all of the above in comprehensive combustion code and validate effects on boiler performance. 7. Perform gasification modeling in support of INEL and commercial customers. The major accomplishments of this project corresponding to these objectives are as follows: 1. Original data for black liquor and biomass data demonstrate dependencies of particle reactions on particle size, liquor type, gas temperature, and gas composition. A comprehensive particle submodel and corresponding data developed during this project predicts particle drying (including both free and chemisorbed moisture), devolatilization, heterogeneous char oxidation, char-smelt reactions, and smelt oxidation. Data and model predictions agree, without adjustment of parameters, within their respective errors. The work performed under these tasks substantially exceeded the original objectives. 2. A separate model for sulfur scavenging and fume formation in a recovery boiler demonstrated strong dependence on both in-boiler mixing and chemistry. In particular, accurate fume particle size predictions, as determined from both laboratory and field measurements, depend on gas mixing effects in the boilers that lead to substantial particle agglomeration. Sulfur scavenging was quantitatively predicted while particle size required one empirical mixing factor to match data. 3. Condensed-phase thermochemistry algorithms were developed for salt

  13. 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.

  14. Final Report, Materials for Industrial Heat Recovery Systems, Tasks 3 and 4 Materials for Heat Recovery in Recovery Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Keiser, James R.; Kish, Joseph R.; Singh, Preet M.; Sarma, Gorti B.; Yuan, Jerry; Gorog, J. Peter; Frederick, Laurie A.; Jette, Francois R.; Meisner, Roberta A.; Singbeil, Douglas L.

    2007-12-31

    The DOE-funded project on materials for industrial heat recovery systems included four research tasks: materials for aluminum melting furnace recuperator tubes, materials and operational changes to prevent cracking and corrosion of the co-extruded tubes that form primary air ports in black liquor recovery boilers, the cause of and means to prevent corrosion of carbon steel tubes in the mid-furnace area of recovery boilers, and materials and operational changes to prevent corrosion and cracking of recovery boiler superheater tubes. Results from studies on the latter two topics are given in this report while separate reports on results for the first two tasks have already been published. Accelerated, localized corrosion has been observed in the mid-furnace area of kraft recovery boilers. This corrosion of the carbon steel waterwall tubes is typically observed in the vicinity of the upper level of air ports where the stainless clad co-extruded wall tubes used in the lower portion of the boiler are welded to the carbon steel tubes that extend from this transition point or “cut line” to the top of the boiler. Corrosion patterns generally vary from one boiler to another depending on boiler design and operating parameters, but the corrosion is almost always found within a few meters of the cut line and often much closer than that. This localized corrosion results in tube wall thinning that can reach the level where the integrity of the tube is at risk. Collection and analysis of gas samples from various areas near the waterwall surface showed reducing and sulfidizing gases were present in the areas where corrosion was accelerated. However, collection of samples from the same areas at intervals over a two year period showed the gaseous environment in the mid-furnace section can cycle between oxidizing and reducing conditions. These fluctuations are thought to be due to gas flow instabilities and they result in an unstable or a less protective scale on the carbon steel

  15. Modelling, simulating and optimizing boiler heating surfaces and evaporator circuits

    DEFF Research Database (Denmark)

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

    2003-01-01

    A model for optimizing the dynamic performance of boiler have been developed. Design variables related to the size of the boiler and its dynamic performance have been defined. The object function to be optimized takes the weight of the boiler and its dynamic capability into account. As constraints...... for the optimization a dynamic model for the boiler is applied. Furthermore a function for the value of the dynamic performance is included in the model. The dynamic models for simulating boiler performance consists of a model for the flue gas side, a model for the evaporator circuit and a model for the drum....... The dynamic model has been developed for the purpose of determining boiler material temperatures and heat transfer from the flue gas side to the water-/steam side in order to simulate the circulation in the evaporator circuit and hereby the water level fluctuations in the drum. The dynamic model has been...

  16. CFD modeling of a boiler's tubes rupture

    International Nuclear Information System (INIS)

    Rahimi, Masoud; Khoshhal, Abbas; Shariati, Seyed Mehdi

    2006-01-01

    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

  17. NOx PREDICTION FOR FBC BOILERS USING EMPIRICAL MODELS

    Directory of Open Access Journals (Sweden)

    Jiří Štefanica

    2014-02-01

    Full Text Available Reliable prediction of NOx emissions can provide useful information for boiler design and fuel selection. Recently used kinetic prediction models for FBC boilers are overly complex and require large computing capacity. Even so, there are many uncertainties in the case of FBC boilers. An empirical modeling approach for NOx prediction has been used exclusively for PCC boilers. No reference is available for modifying this method for FBC conditions. This paper presents possible advantages of empirical modeling based prediction of NOx emissions for FBC boilers, together with a discussion of its limitations. Empirical models are reviewed, and are applied to operation data from FBC boilers used for combusting Czech lignite coal or coal-biomass mixtures. Modifications to the model are proposed in accordance with theoretical knowledge and prediction accuracy.

  18. Questions about the reliability of recovery boilers of steel smelting units

    Energy Technology Data Exchange (ETDEWEB)

    Sazykin, Yu K; Mukhametzyanov, N K

    1979-01-01

    Because the main reason for failure of recovery boilers is contamination of the heating surfaces, the operational conditions of individual elements of boiler units, equipped with vibrational and pulsed cleaning are analyzed and the reliability of the cleaning systems in use today is evaluated. The recovery boilers from open hearth furnaces and two bath steel smelting units from the Magnitogorsk Metallurgic Combine were selected as the subjects of the study. It is established that the boiler heating surface cleaning system has a quite large number of failures. The vibrational cleaning readiness factor is rated at 0.9323 and that of the pulsed cleaning system, 0.9698. For the KU-100 recovery boilers with a mean productivity of 18-20 t/h, the losses caused by failures during operation with vibration and pulsed cleaning were 3,200 and 1,700 rubles per year, respectively. With reconstruction of the boilers, which is associated with an increase in their reliability, the vibration cleaning of the heating surface was replaced by pulsed cleaning.

  19. Atmospheric emission of nitrogen oxide from kraft recovery boilers in Sweden

    International Nuclear Information System (INIS)

    Kjoerk, Anders; Herstad Swaerd, Solvie

    2000-05-01

    Recovery boiler NO x emissions are low compared with those from power boilers. However tighter environmental requirements to decrease the acidic emissions implies that all sources have to be addressed. There are an ongoing evaluation and development of NO x control technologies in the pulp industry. Basically air staging, selective catalytic reduction, SCR, and selective noncatalytic reduction, SNCR, have been discussed. Other NO x control options may be available as a result of ongoing research and development. As a background in the work to reduce the acid rain it has been considered necessary to have a good picture of the NO x emission from recovery boilers, and the Thermal Engineering Research Institute in Sweden have therefore sponsored this study. The intention is to give a good general view and try to explain the reasons for the large differences between boilers. Data from the 30 kraft recovery boilers which were in operation in Sweden during 1999 have been collected. Both NO x levels and specific conditions which could have an influence on the level have been included. The evaluation show a clear correlation between the nitrogen content in the liquor and the NO x level. It seams also that a long retention time in the furnace give an opportunity to reduce the amount of nitrogen oxide. For most boilers in Sweden the NO x levels are reported in mg/MJ and comparison could be done between different types of boilers. However for recovery boilers there could be a large uncertainty in the calculation which gives the amount (mg) of NO x , the definition of the heat input to be used (MJ) is either not clear. As a base for the study the measured concentration in ppm is used instead. The reported values are in the range of 30 - 100 ppm, however the majority of the boilers operate in a more narrow range 60-80 ppm. Air staging and other combustion methods could not reasonably reduce the NO x emission with more than 20% in the next decade. If the goal is higher other

  20. Optimisation of Marine Boilers using Model-based Multivariable Control

    DEFF Research Database (Denmark)

    Solberg, Brian

    Traditionally, marine boilers have been controlled using classical single loop controllers. To optimise marine boiler performance, reduce new installation time and minimise the physical dimensions of these large steel constructions, a more comprehensive and coherent control strategy is needed....... This research deals with the application of advanced control to a specific class of marine boilers combining well-known design methods for multivariable systems. This thesis presents contributions for modelling and control of the one-pass smoke tube marine boilers as well as for hybrid systems control. Much...... of the focus has been directed towards water level control which is complicated by the nature of the disturbances acting on the system as well as by low frequency sensor noise. This focus was motivated by an estimated large potential to minimise the boiler geometry by reducing water level fluctuations...

  1. Model technique for aerodynamic study of boiler furnace

    Energy Technology Data Exchange (ETDEWEB)

    1966-02-01

    The help of the Division was recently sought to improve the heat transfer and reduce the exit gas temperature in a pulverized-fuel-fired boiler at an Australian power station. One approach adopted was to construct from Perspex a 1:20 scale cold-air model of the boiler furnace and to use a flow-visualization technique to study the aerodynamic patterns established when air was introduced through the p.f. burners of the model. The work established good correlations between the behaviour of the model and of the boiler furnace.

  2. Model-based Control of a Bottom Fired Marine Boiler

    DEFF Research Database (Denmark)

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

    2005-01-01

    This paper focuses on applying model based MIMO control to minimize variations in water level for a specific boiler type. A first principles model is put up. The model is linearized and an LQG controller is designed. Furthermore the benefit of using a steam °ow measurement is compared to a strategy...... relying on estimates of the disturbance. Preliminary tests at the boiler system show that the designed controller is able to control the boiler process. Furthermore it can be concluded that relying on estimates of the steam flow in the control strategy does not decrease the controller performance...

  3. Model-based Control of a Bottom Fired Marine Boiler

    DEFF Research Database (Denmark)

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

    This paper focuses on applying model based MIMO control to minimize variations in water level for a specific boiler type. A first principles model is put up. The model is linearized and an LQG controller is designed. Furthermore the benefit of using a steam °ow measurement is compared to a strategy...... relying on estimates of the disturbance. Preliminary tests at the boiler system show that the designed controller is able to control the boiler process. Furthermore it can be concluded that relying on estimates of the steam flow in the control strategy does not decrease the controller performance...

  4. Recovery Act: Oxy-Combustion Techology Development for Industrial-Scale Boiler Applications

    Energy Technology Data Exchange (ETDEWEB)

    Levasseur, Armand

    2014-04-30

    matrix of fuels, oxyprocess variables and boiler design parameters. Significant improvement of CFD modeling tools and validation against 15 MWth experimental data has been completed. Oxy-boiler demonstration and large reference designs have been developed, supported with the information and knowledge gained from the 15 MWth testing. The results from the 15 MWth testing in the BSF and complimentary bench-scale testing are addressed in this volume (Volume II) of the final report. The results of the modeling efforts (Volume III) and the oxy boiler design efforts (Volume IV) are reported in separate volumes.

  5. 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

    1998-12-31

    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

  6. 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

  7. Seismic model of the nuclear boiler SPX2

    International Nuclear Information System (INIS)

    Christodoulou, K.

    1982-01-01

    A model of the nuclear boiler SPX2 is proposed in this paper enabling to carry out comparative calculations on the response to seismic effects. The calculations are made in CISE and SEPTEN departments of Electricite de France [fr

  8. 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...

  9. Thermal performance analysis of Brayton cycle with waste heat recovery boiler for diesel engines of offshore oil production facilities

    International Nuclear Information System (INIS)

    Liu, Xianglong; Gong, Guangcai; Wu, Yi; Li, Hangxin

    2016-01-01

    Highlights: • Comparison of Brayton cycle with WHRB adopted in diesel engines with and without fans by thermal performance. • Waste heat recovery technology for FPSO. • The thermoeconomic analysis for the heat recovery for FPSO. - Abstract: This paper presents the theoretical analysis and on-site testing on the thermal performance of the waste heat recovery system for offshore oil production facilities, including the components of diesel engines, thermal boilers and waste heat boilers. We use the ideal air standard Brayton cycle to analyse the thermal performance. In comparison with the traditional design, the fans at the engine outlet of the waste heat recovery boiler is removed due to the limited space of the offshore platform. The cases with fan and without fan are compared in terms of thermal dynamics performance, energy efficiency and thermo-economic index of the system. The results show that the application of the WHRB increases the energy efficiency of the whole system, but increases the flow resistance in the duct. It is proved that as the waste heat recovery boiler takes the place of the thermal boiler, the energy efficiency of whole system without fan is slightly reduced but heat recovery efficiency is improved. This research provides an important guidance to improve the waste heat recovery for offshore oil production facilities.

  10. 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.

  11. Evaluation of a flue gas driven open absorption system for heat and water recovery from fossil fuel boilers

    International Nuclear Information System (INIS)

    Wang, Zhenying; Zhang, Xiaoyue; Li, Zhen

    2016-01-01

    Highlights: • Flue gas driven open absorption system that efficiently recovers total heat. • Efficient heat and water recovery for various kinds of fossil fuel boilers. • Heat and water recovery efficiencies increase with moisture content of flue gas. • Temperature requirements for district heat supply and domestic hot water were met. • Experimental system surpasses conventional condensing system in total heat recovery. - Abstract: This paper presents an open absorption system for total heat recovery from fossil fuel boilers using the high temperature flue gas as the regeneration heat source. In this system, liquid desiccant serves as the recycling medium, which absorbs waste heat and moisture contained in the low temperature flue gas in the packed tower and then regenerates in the regenerator by the high temperature flue gas. Water vapor generated in the regenerator gets condensed after releasing heat to the heating water system and the condensing water also gets recycled. The return water collects heat from the solution water heat exchanger, the flue gas water heat exchanger and the condenser respectively and is then used for district heating. Driven by the vapor pressure difference between high humidity flue gas and the liquid desiccant, the heat recovery efficiency of the system is not limited by the dew point of the flue gas, enabling a warmer water to be heated up than the conventional condensing boiler. The performance of this system was analyzed theoretically and experimentally and the results showed that the system operated well for both district heat supply and domestic hot water supply. The system efficiency increased with the moisture content of flue gas and the total heat recovery was about 8.5%, 17.2%, 21.2%, and 9.2% higher than the conventional condensing system in the case of coal fired boiler, fuel oil boiler, natural gas boiler, and coke oven gas boiler, respectively.

  12. Energy Balance and Performance Indices for Kraft Recovery Boilers; Standardmetod foer beraekning av energibalans oever sodapanna

    Energy Technology Data Exchange (ETDEWEB)

    Kjoerk, Anders

    2007-09-15

    It has been recognized that different rules exist in calculating energy flows to and from a Recovery boiler. In this report definitions are given with the intention that the branch should adopt a common position in reporting power production for the Swedish system with charge on emission of nitrogen oxides, for the EU Emissions Trading Scheme and for the electricity certificate system. Legislation and guidelines are described as also different standards for determination of boiler efficiency. The definition of the liquor heating value is discussed as also the different ways in which an energy balance could be set up. For the Emissions Trading Scheme a literature survey of interpretations made in other countries has been made. The recommendation is to define the heat input as the product of the virgin liquor flow and the net calorific value of virgin liquor. A net calorific value as defined in SS-ISO 1928 is determined in an environment with excess of oxygen and is consequently named net calorific value in oxidizing condition. In a Recovery boiler part of that heat is required for reduction of sulfur and a net calorific value in reducing condition are therefore defined in a branch specific way. The flow of liquor could be calculated using a heat balance based on steam generation. The envelope for that heat balance could be selected as to fit each individual installation; however some general recommendations are given. In reporting energy flow for the EU Emissions Trading Scheme and to EPA it is recommended to use the net calorific value in oxidizing condition. This definition should also be good for reporting to Statistics Sweden, Swedish Forest Industries Federation and for internal use. For reporting to the electricity certificate system the part of the total power production with origin from biofuel should be stated. The heat of reduction is not available for power production and consequently the recommendation is to use the net calorific value in reducing

  13. Model-free adaptive control of supercritical circulating fluidized-bed boilers

    Science.gov (United States)

    Cheng, George Shu-Xing; Mulkey, Steven L

    2014-12-16

    A novel 3-Input-3-Output (3.times.3) Fuel-Air Ratio Model-Free Adaptive (MFA) controller is introduced, which can effectively control key process variables including Bed Temperature, Excess O2, and Furnace Negative Pressure of combustion processes of advanced boilers. A novel 7-input-7-output (7.times.7) MFA control system is also described for controlling a combined 3-Input-3-Output (3.times.3) process of Boiler-Turbine-Generator (BTG) units and a 5.times.5 CFB combustion process of advanced boilers. Those boilers include Circulating Fluidized-Bed (CFB) Boilers and Once-Through Supercritical Circulating Fluidized-Bed (OTSC CFB) Boilers.

  14. Techno-economic analysis and optimization of the heat recovery of utility boiler flue gas

    International Nuclear Information System (INIS)

    Xu, Gang; Huang, Shengwei; Yang, Yongping; Wu, Ying; Zhang, Kai; Xu, Cheng

    2013-01-01

    Highlights: • Four typical flue gas heat recovery schemes are quantitatively analyzed. • The analysis considers thermodynamic, heat transfer and hydrodynamics factors. • Techno-economic analysis and optimization design are carried out. • High-stage steam substitute scheme obtains better energy-saving effect. • Large heat transfer area and high flue gas resistances weaken overall performance. - Abstract: Coal-fired power plants in China consume nearly half of available coals, and the resulting CO 2 emissions cover over 40% of total national emissions. Therefore, reducing the energy expenditure of coal-fired power plants is of great significance to China’s energy security and greenhouse gas reduction programs. For coal-fired power plants, the temperature of a boiler’s exhaust gas reaches 120–150 °C or even higher. The thermal energy of boiler’s exhaust accounts for approximately 3–8% of the total energy of fuel input. Given these factors, we conducted a techno-economic analysis and optimization design of the heat recovery system using boiler exhaust gas. This research is conformed to the principles of thermodynamic, heat transfer, and hydrodynamics. Based on the data from an existing 1000 MW typical power generation unit in China, four typical flue gas heat recovery schemes are quantitatively analyzed from the thermodynamics perspective. The impacts of flue gas heat recovery on net work output and standard coal consumption rate of various schemes are performed. Furthermore, the transfer area of heat recovery exchanger and the draft fan work increment due to the flue gas pressure drop are analyzed. Finally, a techno-economic analysis of the heat recovery schemes is conducted, and some recommendations on optimization design parameters are proposed, with full consideration of various factors such as the decrease on fuel cost due to energy conservation as well as the investment cost of heat recovery retrofitting. The results revealed that, high

  15. Effective removal of hazardous trace metals from recovery boiler fly ashes.

    Science.gov (United States)

    Kinnarinen, Teemu; Golmaei, Mohammad; Jernström, Eeva; Häkkinen, Antti

    2018-02-15

    The objective of this study is to introduce a treatment sequence enabling straightforward and effective recovery of hazardous trace elements from recovery boiler fly ash (RBFA) by a novel method, and to demonstrate the subsequent removal of Cl and K with the existing crystallization technology. The treatment sequence comprises two stages: dissolution of most other RBFA components than the hazardous trace elements in water in Step 1 of the treatment, and crystallization of the process chemicals in Step 2. Solid-liquid separation has an important role in the treatment, due to the need to separate first the small solid residue containing the trace elements, and to separate the valuable crystals, containing Na and S, from the liquid rich in Cl and K. According to the results, nearly complete recovery of cadmium, lead and zinc can be reached even without pH adjustment. Some other metals, such as Mg and Mn, are removed together with the hazardous metals. Regarding the removal of Cl and K from the process, in this non-optimized case the removal efficiency was satisfactory: 60-70% for K when 80% of sodium was recovered, and close to 70% for Cl when 80% of sulfate was recovered. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. A new conceptual cold-end design of boilers for coal-fired power plants with waste heat recovery

    International Nuclear Information System (INIS)

    Yang, Yongping; Xu, Cheng; Xu, Gang; Han, Yu; Fang, Yaxiong; Zhang, Dongke

    2015-01-01

    Highlights: • A new cold-end design of boilers for CFPPs with waste heat recovery is proposed. • Thermodynamic and economic analyses are quantitatively conducted. • Higher energy efficiency improvement and greater economic benefits are achieved. • Lower exergy destruction and better matched energy level are obtained. - Abstract: After conducting an in-depth analysis of the conventional boiler cold-end design for waste heat recovery, this work proposed a new conceptual boiler cold-end design integrated with the steam cycle in a 1000 MW CFPP, in which the preheating of air was divided into high-temperature air preheater (HTAP), main air preheater (MAP) and low-temperature air preheater (LTAP). The HTAP and an economizer were installed in separate flue ducts, and the low temperature economizer (LTE) was situated between the MAP and the LTAP in the main flue duct to heat the condensed water. In the proposed boiler cold-end design, the flue gas waste heat was not only used to heat condensed water, but also to further preheat the combustion air. The air temperature at the air-preheater outlet increases and part of the steam bleeds with high exergy can be saved, resulting in greater energy-savings and better economics. Results showed that, for a typical 1000 MW CFPP in China, using the proposed boiler cold-end design for waste heat recovery could produce 13.3 MW e additional net power output with a heat rate reduction of approximately 112.0 kJ/kW h and could yield a net benefit of up to $85.8 M per year, which is much greater than those of the conventional cases. Exergy destruction is also reduced from 49.9 MW th in the conventional boiler cold-end design to 39.6 MW th in the proposed design

  17. Factors controlling alkali salt deposition in recovery boilers - particle formation and deposition; Soodakattilan likaantuminen ja siihen vaikuttavien tekijoeiden hallinta - hiukkasten muodostuminen ja depositio

    Energy Technology Data Exchange (ETDEWEB)

    Kauppinen, E.I.; Mikkanen, P.; Ylaetalo, S. [VTT Chemistry, Espoo (Finland); Jokiniemi, J.K.; Lyyraenen, J.; Pyykoenen, J.; Saastamoinen, J. [VTT Energy, Espoo (Finland)

    1996-12-01

    In this project, the aim was to find out those critical factors that control the deposit formation in the recovery boilers. We focus on the particle formation, growth and deposition as well as the single black liquor particle combustion behaviour. The final goal is the development of the predictive model to be used to describe deposit growth and subsequent behaviour as well as the dependence of deposition on black liquor characteristics and boiler operation conditions. During year 1995 an experimental study on the aerosol particle formation within the recovery boiler furnace and a sensitivity study with the Aerosol Behaviour in Combustion (ABC) code were carried out. The experimental study confirmed the fact that the particles are already formed in the recovery boiler furnace. The particle formation is initiated in the boundary layer of the burning droplet or smelt bed, where metals are vaporised and oxidised to form tiny seed particles. Trace amounts of metals were measured in all particle sizes and the sensitivity study with the ABC model gave further evidence of the seed formation was necessary primary step in the particle formation. At the furnace outlet the sintration ratio and the sulfation ratio of the particles were dependent on the furnace temperature and the residence time in the furnace. At ESP inlet three types of particles were observed (1) fine particles with the major mass mode at about 1-2 {mu}m, (2) large agglomerates in sizes larger than 8 {mu}m, and (3) spherical particles about 2-4 {mu}m in size. The fine particles were formed from vapours and the large agglomerates were formed from fine particles agglomerated on heat exchanger surfaces and re-entrained back to flue gas flow. The large agglomerates also contain vapours that have directly condensed to surfaces. The large spherical particles contain silicon and pass the process almost unchanged. (Abstract Truncated)

  18. Recovery Act: Oxy-Combustion Technology Development for Industrial-Scale Boiler Applications

    Energy Technology Data Exchange (ETDEWEB)

    Levasseur, Armand

    2014-01-01

    This Topical Report outlines guidelines and key considerations for design and operation of pulverized coal-fired boilers for oxy-combustion. The scope addressed includes only the boiler island, not the entire oxy-fired CO{sub 2} capture plant. These guidelines are primarily developed for tangential-fired boilers and focus on designs capable of dual air and oxy-fired operation. The guidelines and considerations discussed are applicable to both new units and existing boiler retrofits. These guidelines are largely based on the findings from the extensive 15 MW{sub th} pilot testing and design efforts conducted under this project. A summary level description is provided for each major aspect of boiler design impacted by oxy-combustion, and key considerations are discussed for broader application to different utility and industrial designs. Guidelines address the boiler system arrangement, firing system, boiler thermal design, ducting, materials, control system, and other key systems.

  19. CFD modeling of a boiler's tubes rupture

    Energy Technology Data Exchange (ETDEWEB)

    Rahimi, Masoud; Khoshhal, Abbas; Shariati, Seyed Mehdi [Chemical Engineering Department, Faculty of Engineering, Razi University, Kermanshah (Iran)

    2006-12-15

    This paper reports the results of a study on the reason for tubes damage in the superheater Platen section of the 320MW 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-{epsilon} turbulence model and the Rosseland radiation model were used in the model. The theoretical results showed that the inlet 18.9MPa saturated steam becomes superheated inside the tubes and exit at a pressure of 17.8MPa. 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. (author)

  20. Fate of recovery boiler smelt nitrogen in the recovery cycle; Soodakattilan sulan typpiyhdisteitten kaeyttaeytyminen talteenottoprosessissa

    Energy Technology Data Exchange (ETDEWEB)

    Hupa, M.; Forssen, M.; Backman, R.; Ek, P.; Hulden, S.G.; Kilpinen, P.; Kymaelaeinen, M.; Malm, H. [Aabo Akademi, Turku (Finland). Combustion Chemistry Research Group

    1997-10-01

    The purpose of this project is to study the fate of the nitrogen bound in the inorganic smelt after it enters the dissolving tank. Of special interest is to find in what form this nitrogen can be found further down in the recovery process and especially in what form it can be removed from the process. The aim is to clarify if the nitrogen can be a potential problem in the process or if it can become a potential emission. The work is divided into choosing methods for the analysis of different nitrogen species, collection and analysis of mill samples, laboratory studies and theoretical studies on nitrogen chemistry in alkaline solutions and reporting

  1. Modelling of limestone injection for SO2 capture in a coal fired utility boiler

    International Nuclear Information System (INIS)

    Kovacik, G.J.; Reid, K.; McDonald, M.M.; Knill, K.

    1997-01-01

    A computer model was developed for simulating furnace sorbent injection for SO 2 capture in a full scale utility boiler using TASCFlow TM computational fluid dynamics (CFD) software. The model makes use of a computational grid of the superheater section of a tangentially fired utility boiler. The computer simulations are three dimensional so that the temperature and residence time distribution in the boiler could be realistically represented. Results of calculations of simulated sulphur capture performance of limestone injection in a typical utility boiler operation were presented

  2. Modelling and verification of once-through subcritical heat recovery steam generator

    International Nuclear Information System (INIS)

    Lee, Chae Soo; Choi, Young Jun; Kim, Hyun Gee; Yang, Ok Chul; Chong Chae Hon

    2004-01-01

    The once-through heat recovery steam generator is ideally matched to very high temperature and pressure, well into the supercritical range. Moreover this type of boiler is structurally simpler than drum type boiler. In drum type boiler, each tube play a well-defined role: water preheating, vaporization, superheating. Empirical equations are available to predict the average heat transfer coefficient for each regime. For once-through heat recovery steam generator, this is no more the case and mathematical models have to be adapted to account for the disappearance of drum type economizer, boiler, superheater. General equations have to be used for each tube of boiler, and actual heat transfer condition in each tube has to be identified

  3. An analysis of the thermodynamic efficiency for exhaust gas recirculation-condensed water recirculation-waste heat recovery condensing boilers (EGR-CWR-WHR CB)

    International Nuclear Information System (INIS)

    Lee, Chang-Eon; Yu, Byeonghun; Lee, Seungro

    2015-01-01

    This study presents fundamental research on the development of a new boiler that is expected to have a higher efficiency and lower emissions than existing boilers. The thermodynamic efficiency of exhaust gas recirculation-condensed water recirculation-waste heat recovery condensing boilers (EGR-CWR-WHR CB) was calculated using thermodynamic analysis and was compared with other boilers. The results show the possibility of obtaining a high efficiency when the temperature of the exhaust gas is controlled within 50–60 °C because water in the exhaust gas is condensed within this temperature range. In addition, the enthalpy emitted by the exhaust gas for the new boiler is smaller because the amount of condensed water is increased by the high dew-point temperature and the low exhaust gas temperature. Thus, the new boiler can obtain a higher efficiency than can older boilers. The efficiency of the EGR-CWR-WHR CB proposed in this study is 93.91%, which is 7.04% higher than that of existing CB that is currently used frequently. - Highlights: • The study presents the development of a new boiler expected to have a high efficiency. • Thermodynamic efficiency of EGR-CWR-WHR condensing boiler was calculated. • Efficiency of EGR-CWR-WHR CB is 93.91%, which is 7.04% higher than existing CB

  4. Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Edward Levy; Harun Bilirgen; John DuPoint

    2011-03-31

    Most of the water used in a thermoelectric power plant is used for cooling, and DOE has been focusing on possible techniques to reduce the amount of fresh water needed for cooling. DOE has also been placing emphasis on recovery of usable water from sources not generally considered, such as mine water, water produced from oil and gas extraction, and water contained in boiler flue gas. This report deals with development of condensing heat exchanger technology for recovering moisture from flue gas from coal-fired power plants. The report describes: (1) An expanded data base on water and acid condensation characteristics of condensing heat exchangers in coal-fired units. This data base was generated by performing slip stream tests at a power plant with high sulfur bituminous coal and a wet FGD scrubber and at a power plant firing high-moisture, low rank coals. (2) Data on typical concentrations of HCl, HNO{sub 3} and H{sub 2}SO{sub 4} in low temperature condensed flue gas moisture, and mercury capture efficiencies as functions of process conditions in power plant field tests. (3) Theoretical predictions for sulfuric acid concentrations on tube surfaces at temperatures above the water vapor dewpoint temperature and below the sulfuric acid dew point temperature. (4) Data on corrosion rates of candidate heat exchanger tube materials for the different regions of the heat exchanger system as functions of acid concentration and temperature. (5) Data on effectiveness of acid traps in reducing sulfuric acid concentrations in a heat exchanger tube bundle. (6) Condensed flue gas water treatment needs and costs. (7) Condensing heat exchanger designs and installed capital costs for full-scale applications, both for installation immediately downstream of an ESP or baghouse and for installation downstream of a wet SO{sub 2} scrubber. (8) Results of cost-benefit studies of condensing heat exchangers.

  5. Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Levy, Edward; Bilirgen, Harun; DuPont, John

    2011-03-31

    Most of the water used in a thermoelectric power plant is used for cooling, and DOE has been focusing on possible techniques to reduce the amount of fresh water needed for cooling. DOE has also been placing emphasis on recovery of usable water from sources not generally considered, such as mine water, water produced from oil and gas extraction, and water contained in boiler flue gas. This report deals with development of condensing heat exchanger technology for recovering moisture from flue gas from coal-fired power plants. The report describes: • An expanded data base on water and acid condensation characteristics of condensing heat exchangers in coal-fired units. This data base was generated by performing slip stream tests at a power plant with high sulfur bituminous coal and a wet FGD scrubber and at a power plant firing highmoisture, low rank coals. • Data on typical concentrations of HCl, HNO{sub 3} and H{sub 2}SO{sub 4} in low temperature condensed flue gas moisture, and mercury capture efficiencies as functions of process conditions in power plant field tests. • Theoretical predictions for sulfuric acid concentrations on tube surfaces at temperatures above the water vapor dewpoint temperature and below the sulfuric acid dew point temperature. • Data on corrosion rates of candidate heat exchanger tube materials for the different regions of the heat exchanger system as functions of acid concentration and temperature. • Data on effectiveness of acid traps in reducing sulfuric acid concentrations in a heat exchanger tube bundle. • Condensed flue gas water treatment needs and costs. • Condensing heat exchanger designs and installed capital costs for full-scale applications, both for installation immediately downstream of an ESP or baghouse and for installation downstream of a wet SO{sub 2} scrubber. • Results of cost-benefit studies of condensing heat exchangers.

  6. Experimental validation of a thermodynamic boiler model under steady state and dynamic conditions

    International Nuclear Information System (INIS)

    Carlon, Elisa; Verma, Vijay Kumar; Schwarz, Markus; Golicza, Laszlo; Prada, Alessandro; Baratieri, Marco; Haslinger, Walter; Schmidl, Christoph

    2015-01-01

    Highlights: • Laboratory tests on two commercially available pellet boilers. • Steady state and a dynamic load cycle tests. • Pellet boiler model calibration based on data registered in stationary operation. • Boiler model validation with reference to both stationary and dynamic operation. • Validated model suitable for coupled simulation of building and heating system. - Abstract: Nowadays dynamic building simulation is an essential tool for the design of heating systems for residential buildings. The simulation of buildings heated by biomass systems, first of all needs detailed boiler models, capable of simulating the boiler both as a stand-alone appliance and as a system component. This paper presents the calibration and validation of a boiler model by means of laboratory tests. The chosen model, i.e. TRNSYS “Type 869”, has been validated for two commercially available pellet boilers of 6 and 12 kW nominal capacities. Two test methods have been applied: the first is a steady state test at nominal load and the second is a load cycle test including stationary operation at different loads as well as transient operation. The load cycle test is representative of the boiler operation in the field and characterises the boiler’s stationary and dynamic behaviour. The model had been calibrated based on laboratory data registered during stationary operation at different loads and afterwards it was validated by simulating both the stationary and the dynamic tests. Selected parameters for the validation were the heat transfer rates to water and the water temperature profiles inside the boiler and at the boiler outlet. Modelling results showed better agreement with experimental data during stationary operation rather than during dynamic operation. Heat transfer rates to water were predicted with a maximum deviation of 10% during the stationary operation, and a maximum deviation of 30% during the dynamic load cycle. However, for both operational regimes the

  7. A novel modelling approach for condensing boilers based on hybrid dynamical systems

    NARCIS (Netherlands)

    Satyavada, H.; Baldi, S.

    2016-01-01

    Condensing boilers use waste heat from flue gases to pre-heat cold water entering the boiler. Flue gases are condensed into liquid form, thus recovering their latent heat of vaporization, which results in as much as 10%–12% increase in efficiency. Modeling these heat transfer phenomena is crucial to

  8. Identification and MPC control of a circulation fluidized bed boiler using an LPV model

    NARCIS (Netherlands)

    Huang, J.; Ji, G.; Zhu, Y.; Lin, W.; Kothare, M.; Tade, M.; Vande Wouwer, A.; Smets, I.

    2010-01-01

    This work studies the identification and control of circulation fluidized bed (CFB) boilers. The CFB boiler under investigation shows strong nonlinearity due to big changes of steam load. A linear parameter varying (LPV) model is used to represent the process dynamics and used in control. The steam

  9. Recovery from schizophrenia and the recovery model.

    Science.gov (United States)

    Warner, Richard

    2009-07-01

    The recovery model refers to subjective experiences of optimism, empowerment and interpersonal support, and to a focus on collaborative treatment approaches, finding productive roles for user/consumers, peer support and reducing stigma. The model is influencing service development around the world. This review will assess whether optimism about outcome from serious mental illness and other tenets of the recovery model are borne out by recent research. Remission of symptoms has been precisely defined, but the definition of 'recovery' is a more diffuse concept that includes such factors as being productive and functioning independently. Recent research and a large, earlier body of data suggest that optimism about outcome from schizophrenia is justified. A substantial proportion of people with the illness will recover completely and many more will regain good social functioning. Outcome is better for people in the developing world. Mortality for people with schizophrenia is increasing but is lower in the developing world. Working appears to help people recover from schizophrenia, and recent advances in vocational rehabilitation have been shown to be effective in countries with differing economies and labor markets. A growing body of research supports the concept that empowerment is an important component of the recovery process. Key tenets of the recovery model - optimism about recovery from schizophrenia, the importance of access to employment and the value of empowerment of user/consumers in the recovery process - are supported by the scientific research. Attempts to reduce the internalized stigma of mental illness should enhance the recovery process.

  10. Exergetic Modelling of Oil-Fired Steam Boilers | Ohijeagbon ...

    African Journals Online (AJOL)

    The performance variables and potential for energy savings in oil-fired industrial steam boilers were studied. Operational parameters of steam boilers using low pour fuel oil (LPFO) and diesel were used to determine thermodynamic properties of material streams and exergetic parameters. Analysis of thermodynamic ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-06-21

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

  12. Boiling process modelling peculiarities analysis of the vacuum boiler

    Science.gov (United States)

    Slobodina, E. N.; Mikhailov, A. G.

    2017-06-01

    The analysis of the low and medium powered boiler equipment development was carried out, boiler units possible development directions with the purpose of energy efficiency improvement were identified. Engineering studies for the vacuum boilers applying are represented. Vacuum boiler heat-exchange processes where boiling water is the working body are considered. Heat-exchange intensification method under boiling at the maximum heat- transfer coefficient is examined. As a result of the conducted calculation studies, heat-transfer coefficients variation curves depending on the pressure, calculated through the analytical and numerical methodologies were obtained. The conclusion about the possibility of numerical computing method application through RPI ANSYS CFX for the boiling process description in boiler vacuum volume was given.

  13. Mathematical modelling of a steam boiler room to research thermal efficiency

    International Nuclear Information System (INIS)

    Bujak, J.

    2008-01-01

    This paper introduces a mathematical model of a boiler room to research its thermal efficiency. The model is regarded as an open thermodynamic system exchanging mass, energy, and heat with the atmosphere. On those grounds, the energy and energy balance were calculated. Here I show several possibilities concerning how this model may be applied. Test results of the coefficient of thermal efficiency were compared to a real object, i.e. a steam boiler room of the Provincial Hospital in Wloclawek (Poland). The tests were carried out for 18 months. The results obtained in the boiler room were used for verification of the mathematical model

  14. Numerical modelling of a straw-fired grate boiler

    DEFF Research Database (Denmark)

    Kær, Søren Knudsen

    2004-01-01

    The paper presents a computational fluid dynamics (CFD) analysis of a 33 MW straw-fired grate boiler. Combustion on the grate plays akey-role in the analysis of these boilers and in this work a stand-alone code was used to provide inlet conditions for the CFD analysis. Modelpredictions were...... compared with available gas temperature and species concentration measurements showing good agreement. Combustionof biomass in grate-based boilers is often associated with high emission levels and relatively high amounts of unburnt carbon in the fly ash.Based on the CFD analysis, it is suggested that poor...

  15. Numerical modelling of a straw-fired grate boiler

    DEFF Research Database (Denmark)

    Kær, Søren Knudsen

    2004-01-01

    The paper presents a computational fluid dynamics (CFD) analysis of a 33 MW straw-fired grate boiler. Combustion on the grate plays akey-role in the analysis of these boilers and in this work a stand-alone code was used to provide inlet conditions for the CFD analysis. Modelpredictions were compa...... mixing in the furnace is a key issue leading to these problems. q 2003 Elsevier Ltd. All rights reserved....

  16. Development of an Optimizing Control Concept for Fossil-Fired Boilers using a Simulation Model

    DEFF Research Database (Denmark)

    Mortensen, J. H.; Mølbak, T.; Commisso, M.B.

    1997-01-01

    of implementation and commissioning. The optimizing control system takes into account the multivariable and nonlinear characteristics of the boiler process as a gain-scheduled LQG-controller is utilized. For the purpose of facilitating the control concept development a dynamic simulation model of the boiler process......An optimizing control system for improving the load following capabilities of power plant units has been developed. The system is implemented as a complement producing additive control signals to the existing boiler control system, a concept which has various practical advantages in terms...... model when designing a new control concept are discussed....

  17. Factors controlling deposits in recovery boilers -particle formation and deposition; Soodakattilan likaantuminen ja siihen vaikuttavien tekijoeiden hallinta. Hiukkasten muodostuminen ja depositio

    Energy Technology Data Exchange (ETDEWEB)

    Kauppinen, E I; Mikkanen, P; Tapper, U; Ylaetalo, S; Jaervinen, R [VTT Chemical Technology, Espoo (Finland); Jokiniemi, J K; Pyykoenen, J; Eskola, A [VTT Energy, Espoo (Finland)

    1997-10-01

    In this project the aim is to find critical factors controlling the deposit formation in the recovery boilers. Focus is on particle formation, growth and deposition. During year 1995 the aerosol particle formation was studied by an experimental study within the recovery boiler furnace and by a sensitivity study with the ABC (Aerosol Behaviour in Combustion) computer code. During year 1996 the experimental studies on the aerosol particle formation continued within the furnace and the deposition mechanisms for carry over particles were included in the ABC code and sensitivity studies of the deposition were carried out. The experimental study confirmed the fact that the particles are already formed in the recovery boiler furnace. The particle formation is initiated in the boundary layer of the burning droplet or char bed, where metals are vaporised and oxidised to form tiny seed particles

  18. 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.

  19. Modelling of thermal processes and optimization of energy-ecology characteristics of the modern boiler plants

    International Nuclear Information System (INIS)

    Filkoski, Risto V.

    2004-01-01

    The investigation accomplished in the framework of this work is concerned with the thermal processes in the furnaces of modern steam and hot-water boilers on fossil fuels. Aerodynamic and thermal conditions in the furnaces are described and models for separate processes and phenomena that occur there are presented. By using proper CFD technique, three-dimensional models of furnaces of coal-fired power boiler, hot-water boiler with circulating fluidized bed combustion and steam boiler on liquid/gaseous fuel are created. Graphical pre-processor is used for geometry creation and mesh generation of the investigated boiler plants. Mathematical model for the gas-solids mixture flow is based on Lagrange approach for the discrete phase simulations, in addition to the transport equations for the gas phase. A standard steady semi-empirical k-E model is employed for description of the turbulent flow. Coupling of velocity and pressure is achieved by the SIMPLEC method. Coal combustion is modelled as non-premixed kinetics/diffusion-limited process by the mixture fraction/probability density function approach for the reaction chemistry, with equilibrium assumption applied for description of the system chemistry. Radiation heat transfer is computed by means of the P-1 model, which is simplified variance of the P-N model, based on the expansion of the radiation intensity into an orthogonal series of spherical harmonics. Presence of discrete solid phase in the main gas stream is effectively taken into consideration through additional terms in the radiation energy transfer equation and in other model equations. Variable emissivity coefficient of the combustion products is modelled with the weighted-sum-of-grey gases-model. A model for NO x formation and reduction is included in the computations. Numerical simulations provide results concerning the boilers operation in several regimes. A methodology for optimisation of energetic-ecological characteristics of boiler plants is proposed

  20. Online Monitoring System of Air Distribution in Pulverized Coal-Fired Boiler Based on Numerical Modeling

    Science.gov (United States)

    Żymełka, Piotr; Nabagło, Daniel; Janda, Tomasz; Madejski, Paweł

    2017-12-01

    Balanced distribution of air in coal-fired boiler is one of the most important factors in the combustion process and is strongly connected to the overall system efficiency. Reliable and continuous information about combustion airflow and fuel rate is essential for achieving optimal stoichiometric ratio as well as efficient and safe operation of a boiler. Imbalances in air distribution result in reduced boiler efficiency, increased gas pollutant emission and operating problems, such as corrosion, slagging or fouling. Monitoring of air flow trends in boiler is an effective method for further analysis and can help to appoint important dependences and start optimization actions. Accurate real-time monitoring of the air distribution in boiler can bring economical, environmental and operational benefits. The paper presents a novel concept for online monitoring system of air distribution in coal-fired boiler based on real-time numerical calculations. The proposed mathematical model allows for identification of mass flow rates of secondary air to individual burners and to overfire air (OFA) nozzles. Numerical models of air and flue gas system were developed using software for power plant simulation. The correctness of the developed model was verified and validated with the reference measurement values. The presented numerical model for real-time monitoring of air distribution is capable of giving continuous determination of the complete air flows based on available digital communication system (DCS) data.

  1. Online Monitoring System of Air Distribution in Pulverized Coal-Fired Boiler Based on Numerical Modeling

    Directory of Open Access Journals (Sweden)

    Żymełka Piotr

    2017-12-01

    Full Text Available Balanced distribution of air in coal-fired boiler is one of the most important factors in the combustion process and is strongly connected to the overall system efficiency. Reliable and continuous information about combustion airflow and fuel rate is essential for achieving optimal stoichiometric ratio as well as efficient and safe operation of a boiler. Imbalances in air distribution result in reduced boiler efficiency, increased gas pollutant emission and operating problems, such as corrosion, slagging or fouling. Monitoring of air flow trends in boiler is an effective method for further analysis and can help to appoint important dependences and start optimization actions. Accurate real-time monitoring of the air distribution in boiler can bring economical, environmental and operational benefits. The paper presents a novel concept for online monitoring system of air distribution in coal-fired boiler based on real-time numerical calculations. The proposed mathematical model allows for identification of mass flow rates of secondary air to individual burners and to overfire air (OFA nozzles. Numerical models of air and flue gas system were developed using software for power plant simulation. The correctness of the developed model was verified and validated with the reference measurement values. The presented numerical model for real-time monitoring of air distribution is capable of giving continuous determination of the complete air flows based on available digital communication system (DCS data.

  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. Recovery Act: Oxy-Combustion Technology Development for Industrial-Scale Boiler Applications. Task 4 - Testing in Alstom's 15 MWth Boiler Simulation Facility

    Energy Technology Data Exchange (ETDEWEB)

    Levasseur, Armand

    2014-04-30

    fuels, oxy-process variables and boiler design parameters. Significant improvement of CFD modeling tools and validation against 15 MWth experimental data has been completed. Oxy-boiler demonstration and large reference designs have been developed, supported with the information and knowledge gained from the 15 MWth testing. This report addresses the results from the 15 MWth testing in the BSF.

  4. B and W model boiler tests: effect of temperature on IGA rate. Initial and post-1878 operating conditions of the model boilers

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    The Babcock and Wilcox (B and W) model boiler operated with 10 ppm weekly injections of NaOH for 41,900 hours (4.8 years). The model boiler operating conditions are given. Tube No. 24 failed by caustic intergranular attack/stress corrosion cracking (IGA/SCC) at the steam-water zone. IGA defect depths on tube 24 is compared at different locations, which also have different temperature conditions. The specific locations are: steam/water zone, drilled baffle plate, and lower tube sheet crevice. In all locations caustic will concentrate (although to different concentration levels). Nevertheless, an effect of temperature on IGA rate can be estimated. The degree of attack relative to the location and environment is shown. SEM fractographs illustrate the completely intergranular failure of Tube 24. A summary of the estimated results is presented. These results show the estimated IGA rate as a function of primary/secondary temperature and estimated caustic concentration. Details of the failure analysis of the model boiler can be found in the final report Destructive Examination of Babcock and Wilcox's Model Boiler for Intergranular Attack (IGA) on Tubes, EPRI S302-6, J.L.; Barna and L.W. Sarver

  5. Modeling and optimization of processes for clean and efficient pulverized coal combustion in utility boilers

    Directory of Open Access Journals (Sweden)

    Belošević Srđan V.

    2016-01-01

    Full Text Available Pulverized coal-fired power plants should provide higher efficiency of energy conversion, flexibility in terms of boiler loads and fuel characteristics and emission reduction of pollutants like nitrogen oxides. Modification of combustion process is a cost-effective technology for NOx control. For optimization of complex processes, such as turbulent reactive flow in coal-fired furnaces, mathematical modeling is regularly used. The NOx emission reduction by combustion modifications in the 350 MWe Kostolac B boiler furnace, tangentially fired by pulverized Serbian lignite, is investigated in the paper. Numerical experiments were done by an in-house developed three-dimensional differential comprehensive combustion code, with fuel- and thermal-NO formation/destruction reactions model. The code was developed to be easily used by engineering staff for process analysis in boiler units. A broad range of operating conditions was examined, such as fuel and preheated air distribution over the burners and tiers, operation mode of the burners, grinding fineness and quality of coal, boiler loads, cold air ingress, recirculation of flue gases, water-walls ash deposition and combined effect of different parameters. The predictions show that the NOx emission reduction of up to 30% can be achieved by a proper combustion organization in the case-study furnace, with the flame position control. Impact of combustion modifications on the boiler operation was evaluated by the boiler thermal calculations suggesting that the facility was to be controlled within narrow limits of operation parameters. Such a complex approach to pollutants control enables evaluating alternative solutions to achieve efficient and low emission operation of utility boiler units. [Projekat Ministarstva nauke Republike Srbije, br. TR-33018: Increase in energy and ecology efficiency of processes in pulverized coal-fired furnace and optimization of utility steam boiler air preheater by using in

  6. Modelling of carry-over in recovery furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Fakhrai, Reza [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Metallurgy

    2000-04-01

    Development of mathematical modelling of the combustion process in the furnace of recovery boilers is the subject of this work. This work as a continuation of many years of modelling efforts carried out at KTH/Vaerme- och Ugnsteknik focussed particularly on: char bed modelling; droplets-wall interaction modelling; and carry-over modelling. The char bed model has been studied. Droplets/parcels were considered as a single reactor working independently of the other droplets. The mass of the droplets was not distributed uniformly but induced in the landing place. The droplets hitting the char bed will stick to it and they are alive and part of the calculation. In this way the distribution of the mass on the char bed is only dependent on the parameters which effect flight history such as droplet/parcel diameter, boilers flow field, etc. The droplet- wall interaction model has been studied and found to be very important for obtaining the correct temperature distribution in the recovery furnace. The new approach is based on removal of droplets which hits the wall in the upper part of the recovery boiler from carryover calculation. This model has been proposed and implemented into the GRFM (General Recovery Furnace Model). The carryover modelling effort was based on mass balance in which the number and physical statistics of the droplets/parcel were estimated and the amount of unburned mass was calculated. All of the above listed models were tested together with all other models of heat and mass transfer processes in recovery furnaces using a GRFM. Three-dimensional numerical simulations of the industrial recovery boiler (63 kg/s, 82 bar, 480 deg C) were performed. The number of grid was 232,000 and the number of air ports in this simulation was 178. The air entering the furnace by these ports has different flow rates. Flow and temperature fields as well as species distributions were calculated. The results show good agreement with previously published data and modelling

  7. A Model for Optimization and Analysis of Energy Flexible Boiler Plants for Building Heating Purposes

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, J R

    1996-05-01

    This doctoral thesis presents a model for optimization and analysis of boiler plants. The model optimizes a boiler plant with respect to the annual total costs or with respect to energy consumption. The optimum solution is identified for a given number of energy carriers and defined characteristics of the heat production units. The number of heat production units and the capacity of units related to each energy carrier or the capacity of units related to the same energy carrier can be found. For a problem comprising large variation during a defined analysis period the model gives the operating costs and energy consumption to be used in an extended optimization. The model can be used to analyse the consequences with respect to costs and energy consumption due to capacity margins and shifts in the boundary conditions. The model is based on a search approach comprising an operational simulator. The simulator is based on a marginal cost method and dynamic programming. The simulation is performed on an hourly basis. A general boiler characteristic representation is maintained by linear energy or cost functions. The heat pump characteristics are represented by tabulated performance and efficiency as function of state and nominal aggregate capacities. The simulation procedure requires a heat load profile on an hourly basis. The problem of the presence of capacity margins in boiler plants is studied for selected cases. The single-boiler, oil-fired plant is very sensitive to the magnitude of the losses present during burner off-time. For a plant comprising two oil-fired burners, the impact of a capacity margin can be dampened by the selected capacity configuration. The present incentive, in Norway, to install an electric element boiler in an oil-fired boiler plant is analysed. 77 refs., 74 figs., 12 tabs.

  8. Extended state observer based fuzzy model predictive control for ultra-supercritical boiler-turbine unit

    International Nuclear Information System (INIS)

    Zhang, Fan; Wu, Xiao; Shen, Jiong

    2017-01-01

    Highlights: • A novel ESOFMPC is proposed based on the combination of ESO and stable MPC. • The improved ESO can overcome unknown disturbances on any channel of MIMO system. • Nonlinearity and disturbance of boiler-turbine unit can be handled simultaneously. - Abstract: The regulation of ultra-supercritical (USC) boiler-turbine unit in large-scale power plants is vulnerable to various unknown disturbances, meanwhile, the internal nonlinearity makes it a challenging task for wide range load tracking. To overcome these two issues simultaneously, an extended state observer based fuzzy model predictive control is proposed for the USC boiler-turbine unit. Firstly, the fuzzy model of a 1000-MW coal-fired USC boiler-turbine unit is established through the nonlinearity analysis. Then a fuzzy stable model predictive controller is devised on the fuzzy model using output cost function for the purpose of wide range load tracking. An improved linear extended state observer, which can estimate plant behavior variations and unknown disturbances regardless of the direct feedthrough characteristic of the system, is synthesized with the predictive controller to enhance its disturbance rejection property. Closed-loop stability of the overall control system is guaranteed. Simulation results on a 1000-MW USC boiler-turbine unit model demonstrate the effectiveness of the proposed approach.

  9. Methodology for identifying parameters for the TRNSYS model Type 210 - wood pellet stoves and boilers

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Tomas; Fiedler, Frank; Nordlander, Svante

    2006-05-15

    This report describes a method how to perform measurements on boilers and stoves and how to identify parameters from the measurements for the boiler/stove-model TRNSYS Type 210. The model can be used for detailed annual system simulations using TRNSYS. Experience from measurements on three different pellet stoves and four boilers were used to develop this methodology. Recommendations for the set up of measurements are given and the required combustion theory for the data evaluation and data preparation are given. The data evaluation showed that the uncertainties are quite large for the measured flue gas flow rate and for boilers and stoves with high fraction of energy going to the water jacket also the calculated heat rate to the room may have large uncertainties. A methodology for the parameter identification process and identified parameters for two different stoves and three boilers are given. Finally the identified models are compared with measured data showing that the model generally agreed well with measured data during both stationary and dynamic conditions.

  10. Use of Neural Networks for modeling and predicting boiler's operating performance

    International Nuclear Information System (INIS)

    Kljajić, Miroslav; Gvozdenac, Dušan; Vukmirović, Srdjan

    2012-01-01

    The need for high boiler operating performance requires the application of improved techniques for the rational use of energy. The analysis presented is guided by an effort to find possibilities for ways energy resources can be used wisely to secure a more efficient final energy supply. However, the biggest challenges are related to the variety and stochastic nature of influencing factors. The paper presents a method for modeling, assessing, and predicting the efficiency of boilers based on measured operating performance. The method utilizes a neural network approach to analyze and predict boiler efficiency and also to discover possibilities for enhancing efficiency. The analysis is based on energy surveys of 65 randomly selected boilers located at over 50 sites in the northern province of Serbia. These surveys included a representative range of industrial, public and commercial users of steam and hot water. The sample covered approximately 25% of all boilers in the province and yielded reliable and relevant results. By creating a database combined with soft computing assistance a wide range of possibilities are created for identifying and assessing factors of influence and making a critical evaluation of practices used on the supply side as a source of identified inefficiency. -- Highlights: ► We develop the model for assessing and predicting efficiency of boilers. ► The method implies the use of Artificial Neural Network approach for analysis. ► The results obtained correspond well to collected and measured data. ► Findings confirm and present good abilities of preventive or proactive approach. ► Analysis reveals and specifies opportunities for increasing efficiency of boilers.

  11. Mathematical modeling and experimental study of biomass combustion in a thermal 108 MW grate-fired boiler

    DEFF Research Database (Denmark)

    Yin, Chungen; Rosendahl, Lasse; Kær, Søren K.

    2008-01-01

    Grate boilers are widely used to fire biomass for heat and power production. However grate-firing systems are often reported to have relatively high un-burnout, low efficiency and high emissions, and need to be optimized and modernized. This paper presents the efforts towards a reliable baseline...... computational fluid dynamics (CFD) model for an industrial biomass-fired grate boiler, which can be used for diagnosis and optimization of the grate boiler as well as design of new grate boilers. First, based on the design conditions, a thorough sensitivity analysis is done to evaluate the relative importance...... of different factors in CFD analysis of the grate boiler. In a late stage, a two-day measuring campaign is carried out to measure the gas temperatures and gas concentrations in the boiler using a fiber optic probe connected to a Fourier transform infrared (FTIR) spectrometer. A baseline model is then defined...

  12. Modeling and experiments of biomass combustion in a large-scale grate boiler

    DEFF Research Database (Denmark)

    Yin, Chungen; Rosendahl, Lasse; Kær, Søren Knudsen

    2007-01-01

    is inherently more difficult due to the complexity of the solid biomass fuel bed on the grate, the turbulent reacting flow in the combustion chamber and the intensive interaction between them. This paper presents the CFD validation efforts for a modern large-scale biomass-fired grate boiler. Modeling...... and experiments are both done for the grate boiler. The comparison between them shows an overall acceptable agreement in tendency. However at some measuring ports, big discrepancies between the modeling and the experiments are observed, mainly because the modeling-based boundary conditions (BCs) could differ...

  13. Data Analytics Based Dual-Optimized Adaptive Model Predictive Control for the Power Plant Boiler

    Directory of Open Access Journals (Sweden)

    Zhenhao Tang

    2017-01-01

    Full Text Available To control the furnace temperature of a power plant boiler precisely, a dual-optimized adaptive model predictive control (DoAMPC method is designed based on the data analytics. In the proposed DoAMPC, an accurate predictive model is constructed adaptively by the hybrid algorithm of the least squares support vector machine and differential evolution method. Then, an optimization problem is constructed based on the predictive model and many constraint conditions. To control the boiler furnace temperature, the differential evolution method is utilized to decide the control variables by solving the optimization problem. The proposed method can adapt to the time-varying situation by updating the sample data. The experimental results based on practical data illustrate that the DoAMPC can control the boiler furnace temperature with errors of less than 1.5% which can meet the requirements of the real production process.

  14. Study of immersed heat exchange surface for high efficiency heat recovery from wire rim tires in a fluidized bed boiler; Hai tire nado kara no kokoritsu netsukaishuyo ryudosho boiler no sonai dennetsukan no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Oshita, T; Nagato, S; Miyoshi, N; Hosoda, S [Ebara Corp., Tokyo (Japan)

    1996-07-10

    In an ICFB boiler, the fluidized bed is separated by a partition into the main combustion and the heat recovery chambers. The flows in these chambers are generated by using silica sand as the fluidizing medium. To determine the overall heat transfer coefficient (HTC) of the boiler`s panel type immersed heat transfer tulles, combustion tests were performed with wire rim tires. The overall HTC of a panel tube array was lower than that of a zigzag tube arrangement. In practice, the heat absorbed by the fins makes the coefficients of either type of tube array almost identical. The air flow rate in the circulating bed at the loot Tom of the heat recovery chamber can be changed to control the overall HTC to a value virtually identical with that of a zigzag tube array. The combustion of wire rim tires leads to a buildup of wires in the zigzag array hampering the transfer of heat. Yet, the panel type array showed no buildup so that it was possible to maintain steady operation with this type of tube arrangement. 8 refs., 10 figs., 2 tabs.

  15. Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

    Directory of Open Access Journals (Sweden)

    Balicki Adrian

    2014-06-01

    Full Text Available Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of ‘zeroemission’ technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes.

  16. CFD Modelling of Biomass Combustion in Small-Scale Boilers. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Xue-Song Bai; Griselin, Niklas; Klason, Torbern; Nilsson, Johan [Lund Inst. of Tech. (Sweden). Dept. of Heat and Power Engineering

    2002-10-01

    This project deals with CFD modeling of combustion of wood in fixed bed boilers. A flamelet model for the interaction between turbulence and chemical reactions is developed and applied to study small-scale boiler. The flamelet chemistry employs 43 reactive species and 174 elementary reactions. It gives detailed distributions of important species such as CO and NO{sub x} in the flow field and flue gas. Simulation of a small-scale wood fired boiler measured at SP Boraas (50 KW) shows that the current flamelet model yields results agreeable to the available experimental data. A detailed chemical kinetic model is developed to study the bed combustion process. This model gives boundary conditions for the CFD analysis of gas phase volatile oxidation in the combustion chambers. The model combines a Functional Group submodel with a Depolymerisation, Vaporisation and Crosslinking submodel. The FG submodel simulates how functional groups decompose and form light gas species. The DVC submodell predicts depolymerisation and vaporisation of the macromolecular network and this includes bridge breaking and crosslinking processes, where the wood structure breaks down to fragments. The light fragments form tar and the heavy ones form metaplast. Two boilers firing wood log/chips are studied using the FG-DVC model, one is the SP Boraas small-scale boiler (50 KW) and the other is the Sydkraft Malmoe Vaerme AB's Flintraennan large-scale boiler (55 MW). The fix bed is assumed to be two zones, a partial equilibrium drying/devolatilisation zone and an equilibrium zone. Three typical biomass conversion modes are simulated, a lean fuel combustion mode, a near-stoichiometric combustion and a fuel rich gasification mode. Detailed chemical species and temperatures at different modes are obtained. Physical interpretation is provided. Comparison of the computational results with experimental data shows that the model can reasonably simulate the fixed bed biomass conversion process. CFD

  17. Low Load Model of a Once-through Boiler with Recirculation

    DEFF Research Database (Denmark)

    Trangbæk, Klaus

    2006-01-01

    A dynamic simulation model of a once-through boiler in low to medium load is developed. When the system is in low load, water from the evaporator is recirculated through a bottle. This recirculation system is included in the model, which is then shown to fit closed-loop data from a real plant...

  18. Characterizing and modeling of an 88 MW grate-fired boiler burning wheat straw: Experience and lessons

    DEFF Research Database (Denmark)

    Yin, Chungen; Rosendahl, Lasse Aistrup; Clausen, Sønnik

    2012-01-01

    and availability. To better understand grate-firing of biomass and to establish a reliable but relatively simple Computational Fluid Dynamics (CFD) modeling methodology for industrial applications, biomass combustion in a number of different grate boilers has been measured and modeled. As one of the case studies......, modeling effort on an 88 MW grate-fired boiler burning wheat straw is presented in this paper. Different modeling issues and their expected impacts on CFD analysis of the kind of grate boilers are discussed. The modeling results are compared with in-flame measurements in the 88 MW boiler, which shows...... measures will be tested in a modern 500 kW grate boiler rig...

  19. Advanced modelling and testing of a 13 MWth waste wood-fired grate boiler with recycled flue gas

    DEFF Research Database (Denmark)

    Rajh, Boštjan; Yin, Chungen; Samec, Niko

    2016-01-01

    as an innovative attempt to improve the boiler performance, a refined weighted-sum-of-grey-gases-model of greater accuracy is developed to better address the impacts of the elevated CO2 and H2O vapour concentrations on radiative heat transfer in the boiler. The impacts of full buoyancy on the turbulent flow...

  20. Mixing Studies in a 1:60 scale model of a cornerfired boiler with OFA

    DEFF Research Database (Denmark)

    Matlok, Simon; Scheel Larsen, Poul; Gjernes, Erik

    1998-01-01

    In a model of a boiler, concentration distributions of injected gas into a swirling bulk flow are determined from quantitative laser-sheet visualization. Together with LDA-measurements of velocity fields this describes the mixing process and its efficiency expressed by several measures (unmixedness...

  1. Model-based adaptive sliding mode control of the subcritical boiler-turbine system with uncertainties.

    Science.gov (United States)

    Tian, Zhen; Yuan, Jingqi; Xu, Liang; Zhang, Xiang; Wang, Jingcheng

    2018-05-25

    As higher requirements are proposed for the load regulation and efficiency enhancement, the control performance of boiler-turbine systems has become much more important. In this paper, a novel robust control approach is proposed to improve the coordinated control performance for subcritical boiler-turbine units. To capture the key features of the boiler-turbine system, a nonlinear control-oriented model is established and validated with the history operation data of a 300 MW unit. To achieve system linearization and decoupling, an adaptive feedback linearization strategy is proposed, which could asymptotically eliminate the linearization error caused by the model uncertainties. Based on the linearized boiler-turbine system, a second-order sliding mode controller is designed with the super-twisting algorithm. Moreover, the closed-loop system is proved robustly stable with respect to uncertainties and disturbances. Simulation results are presented to illustrate the effectiveness of the proposed control scheme, which achieves excellent tracking performance, strong robustness and chattering reduction. Copyright © 2018. Published by Elsevier Ltd.

  2. Dynamic model of a natural water circulation boiler suitable for on-line monitoring of fossil/alternative fuel plants

    International Nuclear Information System (INIS)

    Sedić, Almir; Katulić, Stjepko; Pavković, Danijel

    2014-01-01

    Highlights: • Derivation of dynamic model of a natural water circulation boiler is presented. • Model is derived by employing basic laws of conservation of mass, energy and momentum. • Thus obtained boiler model does not include empirical relationships. • Model is validated against experimental data related to an external disturbance event. • The final model is used for simulation analysis/assessment of key boiler quantities. - Abstract: The environmental protection policies and legal obligations motivate process industries to implement new low-emission and high-efficiency technologies. For the purpose of production process optimization and related control system design it is worthwhile to first build an appropriate process model. Apart from favorable execution speed, accuracy, and reliability features, the model also needs to be straightforward and only include the physical and design characteristics of the overall plant and its individual components, instead of relying on empirical relationships. To this end, this paper presents a nonlinear dynamic model of the single-drum natural-circulation steam boiler evaporator circuit, based exclusively on the fundamental physical laws of conservation of mass, energy and momentum, wherein the reliance upon empirical relationships has been entirely avoided. The presented boiler system modeling approach is based on the analysis of the physical phenomena within the boiler drum, as well as within downcomer and furnace tubes, and it also takes into account the boiler system design-specific features such as cyclone steam separators, thus facilitating the derivation of a fully-physical process model. Due to the straightforwardness of the derived process model, it should also be useful for the analysis of similar steam boiler facilities, requiring only adjustments of key operational and design parameters such as operating pressure, temperature, steam capacity and characteristics of ancillary equipment such as pumps. To

  3. Furnace and Heat Recovery Area Design and Analysis for Conceptual Design of Supercritical O2-Based PC Boiler

    International Nuclear Information System (INIS)

    Andrew Seltzer

    2006-01-01

    The objective of the furnace and heat recovery area design and analysis task of the Conceptual Design of Supercritical Oxygen-Based PC Boiler study is to optimize the location and design of the furnace, burners, over-fire gas ports, and internal radiant surfaces. The furnace and heat recovery area were designed and analyzed using the FW-FIRE, Siemens, and HEATEX computer programs. The furnace is designed with opposed wall-firing burners and over-fire air ports. Water is circulated in the furnace by forced circulation to the waterwalls at the periphery and divisional wall panels within the furnace. Compared to the air-fired furnace, the oxygen-fired furnace requires only 65% of the surface area and 45% of the volume. Two oxygen-fired designs were simulated: (1) with cryogenic air separation unit (ASU) and (2) with oxygen ion transport membrane (OITM). The maximum wall heat flux in the oxygen-fired furnace is more than double that of the air-fired furnace due to the higher flame temperature and higher H 2 O and CO 2 concentrations. The coal burnout for the oxygen-fired case is 100% due to a 500 F higher furnace temperature and higher concentration of O 2 . Because of the higher furnace wall temperature of the oxygen-fired case compared to the air-fired case, furnace water wall material was upgraded from T2 to T92. Compared to the air-fired heat recovery area (HRA), the oxygen-fired HRA total heat transfer surface is 35% less for the cryogenic design and 13% less for the OITM design due to more heat being absorbed in the oxygen-fired furnace and the greater molecular weight of the oxygen-fired flue gas. The HRA tube materials and wall thickness are nearly the same for the air-fired and oxygen-fired design since the flue gas and water/steam temperature profiles encountered by the heat transfer banks are similar

  4. Advanced char burnout models for the simulation of pulverized coal fired boilers

    Energy Technology Data Exchange (ETDEWEB)

    T. Severin; S. Wirtz; V. Scherer [Ruhr-University, Bochum (Germany). Institute of Energy Plant Technology (LEAT)

    2005-07-01

    The numerical simulation of coal combustion processes is widely used as an efficient means to predict burner or system behaviour. In this paper an approach to improve CFD simulations of pulverized coal fired boilers with advanced coal combustion models is presented. In simple coal combustion models, first order Arrhenius rate equations are used for devolatilization and char burnout. The accuracy of such simple models is sufficient for the basic aspects of heat release. The prediction of carbon-in-ash is one aspect of special interest in the simulation of pulverized coal fired boilers. To determine the carbon-in-ash levels in the fly ash of coal fired furnaces, the char burnout model has to be more detailed. It was tested, in how far changing operating conditions affect the carbon-in-ash prediction of the simulation. To run several test cases in a short time, a simplified cellnet model was applied. To use a cellnet model for simulations of pulverized coal fired boilers, it was coupled with a Lagrangian particle model, used in CFD simulations, too. 18 refs., 5 figs., 5 tabs.

  5. [Hazard evaluation modeling of particulate matters emitted by coal-fired boilers and case analysis].

    Science.gov (United States)

    Shi, Yan-Ting; Du, Qian; Gao, Jian-Min; Bian, Xin; Wang, Zhi-Pu; Dong, He-Ming; Han, Qiang; Cao, Yang

    2014-02-01

    In order to evaluate the hazard of PM2.5 emitted by various boilers, in this paper, segmentation of particulate matters with sizes of below 2. 5 microm was performed based on their formation mechanisms and hazard level to human beings and environment. Meanwhile, taking into account the mass concentration, number concentration, enrichment factor of Hg, and content of Hg element in different coal ashes, a comprehensive model aimed at evaluating hazard of PM2.5 emitted by coal-fired boilers was established in this paper. Finally, through utilizing filed experimental data of previous literatures, a case analysis of the evaluation model was conducted, and the concept of hazard reduction coefficient was proposed, which can be used to evaluate the performance of dust removers.

  6. Burnout of pulverized biomass particles in large scale boiler - Single particle model approach

    Energy Technology Data Exchange (ETDEWEB)

    Saastamoinen, Jaakko; Aho, Martti; Moilanen, Antero [VTT Technical Research Centre of Finland, Box 1603, 40101 Jyvaeskylae (Finland); Soerensen, Lasse Holst [ReaTech/ReAddit, Frederiksborgsveij 399, Niels Bohr, DK-4000 Roskilde (Denmark); Clausen, Soennik [Risoe National Laboratory, DK-4000 Roskilde (Denmark); Berg, Mogens [ENERGI E2 A/S, A.C. Meyers Vaenge 9, DK-2450 Copenhagen SV (Denmark)

    2010-05-15

    Burning of coal and biomass particles are studied and compared by measurements in an entrained flow reactor and by modelling. The results are applied to study the burning of pulverized biomass in a large scale utility boiler originally planned for coal. A simplified single particle approach, where the particle combustion model is coupled with one-dimensional equation of motion of the particle, is applied for the calculation of the burnout in the boiler. The particle size of biomass can be much larger than that of coal to reach complete burnout due to lower density and greater reactivity. The burner location and the trajectories of the particles might be optimised to maximise the residence time and burnout. (author)

  7. Burnout of pulverized biomass particles in large scale boiler – Single particle model approach

    DEFF Research Database (Denmark)

    Saastamoinen, Jaakko; Aho, Martti; Moilanen, Antero

    2010-01-01

    the particle combustion model is coupled with one-dimensional equation of motion of the particle, is applied for the calculation of the burnout in the boiler. The particle size of biomass can be much larger than that of coal to reach complete burnout due to lower density and greater reactivity. The burner...... location and the trajectories of the particles might be optimised to maximise the residence time and burnout....

  8. IGA/SCC propagation rate measurements on alloy 600 steam generator tubing using a side stream model boiler

    International Nuclear Information System (INIS)

    Takamatsu, H.; Matsueda, K.; Matsunaga, T.; Kitera, T.; Arioka, K.; Tsuruta, T.; Okamoto, S.

    1993-01-01

    IGA/SCC crack propagation rate measurements using various types of IGA/SCC predefected ALloy 600 tubing were tested in model boilers, a side stream model boiler at Ohi Unit 1 and similar model boilers in the laboratory. Types of IGA/SCC predefects introduced from the outside of the tubing were as follows. (1) Actual IGA/SCC predefect introduced by high temperature caustic environments; (2) Longitudinal predefect by electrodischarge machining (EDM) method, and then crack tip fatigue was introduced to serve as the marker on the fractured surface (EDM slit + fatigue). IGA/SCC crack propagation rate was measured after the destructive examination by Cr concentration profile on fracture surface for (1), and observation of intergranular fractured surface propagated from the marked fatigue was employed for (2) and (3) after the model boiler tests. As for the water chemistry conditions, mainly AVT (high N 2 H 4 ) + boric acid (5-10ppm as B in SGs) treatment for both model boilers, and some of the tests for the model boiler in the laboratory employed AVT (high N 2 H 4 ) without boric acid. The results of IGA/SCC crack propagation rate measurements were compared with each other, and the three methods employed showed a good coincidence with the rate of ca. 1 x 10 -5 mm/Hr for AVT (high N 2 H 4 ) + boric acid treatment condition, in the case that crack tip boron intensity (B/O value by IMMA analysis) of more than 1 was observed

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

    Directory of Open Access Journals (Sweden)

    Li Sun

    2014-01-01

    Full Text Available 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 dually from the noisy measurable outputs. The estimated parameter is compared with the normal value. Then the modified Bayesian algorithm is adopted for fault detection and diagnosis (FDD. The simulation results demonstrate that the approach is feasible and effective.

  10. Data-Reconciliation Based Fault-Tolerant Model Predictive Control for a Biomass Boiler

    Directory of Open Access Journals (Sweden)

    Palash Sarkar

    2017-02-01

    Full Text Available This paper presents a novel, effective method to handle critical sensor faults affecting a control system devised to operate a biomass boiler. In particular, the proposed method consists of integrating a data reconciliation algorithm in a model predictive control loop, so as to annihilate the effects of faults occurring in the sensor of the flue gas oxygen concentration, by feeding the controller with the reconciled measurements. Indeed, the oxygen content in flue gas is a key variable in control of biomass boilers due its close connections with both combustion efficiency and polluting emissions. The main benefit of including the data reconciliation algorithm in the loop, as a fault tolerant component, with respect to applying standard fault tolerant methods, is that controller reconfiguration is not required anymore, since the original controller operates on the restored, reliable data. The integrated data reconciliation–model predictive control (MPC strategy has been validated by running simulations on a specific type of biomass boiler—the KPA Unicon BioGrate boiler.

  11. [Combustion zone investigation and modelling in fuel flexible suspension fired boilers]. Result summary and status

    Energy Technology Data Exchange (ETDEWEB)

    Lovmand Hvid, S.

    2011-12-15

    The project has been designed to obtain data from a power plant boiler with co-combustion, partly to gain greater knowledge of particle turnover in the fuel zone, partly to support the development of modeling tools. Data collection occurred at Studstrup Power Station Unit 4, where the fuel is a combination of coal and biomass. The boiler is equipped with 24 dust burners, four of which have been converted to firing with biomass. Measurements have been carried out in the flame zone with different fuels: coal alone, coal + straw and coal + wood. During the experiments velocity fields, temperature fields and gas concentration fields were measured in the firing zone. Also, particle samples from the flame zone ware collected. Several measurements are performed with well-known techniques, but in addition, the project developed new optical measurement methods based on UV spectroscopy. They allow measuring other gases than the hitherto known methods and allow you to gain insight into the dynamic variations beyond just mean fields. The collection of particle samples from the boiler was, as expected, a very challenging task under the given conditions, but was carried out with a largely satisfactory result. Analysis of the samples has initially failed to lead to an increased recognition of the speed of the conversion process, but the samples will be analyzed in more detail in other projects. (LN)

  12. 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.

  13. Predictive ability of boiler production models | Ogundu | Animal ...

    African Journals Online (AJOL)

    The weekly body weight measurements of a growing strain of Ross broiler were used to compare the of ability of three mathematical models (the multi, linear, quadratic and Exponential) to predict 8 week body weight from early body measurements at weeks I, II, III, IV, V, VI and VII. The results suggest that the three models ...

  14. Modelling of boiler heating surfaces and evaporator circuits

    DEFF Research Database (Denmark)

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

    2002-01-01

    the circulation in the evaporator circuit. The models have been developed as Differential-Algebraic-Equations (DAE) and MATLAB has been applied for the integration of the models. In general MATLAB has proved to be very stable for the relatively stiff equation systems. Experimental verification is planned...

  15. CREATION OF OPTIMIZATION MODEL OF STEAM BOILER RECUPERATIVE AIR HEATER

    Directory of Open Access Journals (Sweden)

    N. B. Carnickiy

    2006-01-01

    Full Text Available The paper proposes to use a mathematical modeling as one of the ways intended to improve quality of recuperative air heater design (RAH without significant additional costs, connected with the change of design materials or fuel type. The described conceptual mathematical AHP optimization model of RAH consists of optimized and constant parameters, technical limitations and optimality criteria.The paper considers a methodology for search of design and regime parameters of an air heater which is based on the methods of multi-criteria optimization. Conclusions for expediency of the given approach usage are made in the paper.

  16. Research of power fuel low-temperature vortex combustion in industrial boiler based on numerical modelling

    Directory of Open Access Journals (Sweden)

    Orlova K.Y.

    2017-01-01

    Full Text Available The goal of the presented research is to perform numerical modelling of fuel low-temperature vortex combustion in once-through industrial steam boiler. Full size and scaled-down furnace model created with FIRE 3D software and was used for the research. All geometrical features were observed. The baseline information for the low-temperature vortex furnace process are velocity and temperature of low, upper and burner blast, air-fuel ratio, fuel consumption, coal dust size range. The obtained results are: temperature and velocity three dimensional fields, furnace gases and solid fuel ash particles concentration.

  17. Practical Validation of Economic Efficiency Modelling Method for Multi-Boiler Heating System

    Directory of Open Access Journals (Sweden)

    Aleksejs Jurenoks

    2017-12-01

    Full Text Available In up-to-date conditions information technology is frequently associated with the modelling process, using computer technology as well as information networks. Statistical modelling is one of the most widespread methods of research of economic systems. The selection of methods of modelling of the economic systems depends on a great number of conditions of the researched system. Modelling is frequently associated with the factor of uncertainty (or risk, who’s description goes outside the confines of the traditional statistical modelling, which, in its turn, complicates the modelling which, in its turn, complicates the modelling process. This article describes the modelling process of assessing the economic efficiency of a multi-boiler adaptive heating system in real-time systems which allows for dynamic change in the operation scenarios of system service installations while enhancing the economic efficiency of the system in consideration.

  18. Physical characterization of biomass fuels prepared for suspension firing in utility boilers for CFD modelling

    DEFF Research Database (Denmark)

    Rosendahl, Lasse; Yin, Chungen; Kær, Søren Knudsen

    2007-01-01

    A sample of 1.2 kg Danish wheat straw (Jutland, 1997) prepared for suspension firing in a PF boiler has been analyzed for the purpose of generating size and shape distribution functions applicable to numerical modelling of combustion processes involving biomass, characterised by highly anisotropic...... shapes. The sample is subdivided by straw type, and coherent size, type and mass distribution parameters are reported for the entire sample. This type of data is necessary in order to use CFD reliably as a design and retrofit tool for co-firing biomass with fossil fuels, as the combustion processes...

  19. Experimental investigation and mathematical modelling of wood combustion in a moving grate boiler

    International Nuclear Information System (INIS)

    Zhang, Xiaohui; Chen, Qun; Sharifi, Vida; Swithenbank, Jim; Bradford, Richard

    2010-01-01

    The use of biomass to generate energy offers significant environmental advantages for the reduction in emissions of greenhouse gases. The main objective of this study was to investigate the performance of a small scale biomass heating plant: i.e. combustion characteristics and emissions. An extensive series of experimental tests was carried out at a small scale residential biomass heating plant i.e. wood chip fired boiler. The concentrations of CO, NO x , particulate matter in the flue gas were measured. In addition, mathematical modelling work using FLIC and FLUENT codes was carried out in order to simulate the overall performance of the wood fired heating system. Results showed that pollutant emissions from the boiler were within the relative emission limits. Mass concentration of CO emission was 550-1600 mg/m 3 (10% O 2 ). NO x concentration in the flue gas from the wood chips combustion varied slightly between 28 and 60 ppmv. Mass concentration of PM 10 in the flue gas was 205 mg/m 3 (10% O 2 ) The modelling results showed that most of the fuel was burnt inside the furnace and little CO was released from the system due to the high flue gas temperature in the furnace. The injection of the secondary air provided adequate mixing and favourable combustion conditions in the over-bed chamber in the wood chips fired boiler. This study has shown that the use of wood heating system result in much lower CO 2 emissions than from a fossil fuel e.g. coal fired heating system. (author)

  20. BPACK -- A computer model package for boiler reburning/co-firing performance evaluations. User`s manual, Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Wu, K.T.; Li, B.; Payne, R.

    1992-06-01

    This manual presents and describes a package of computer models uniquely developed for boiler thermal performance and emissions evaluations by the Energy and Environmental Research Corporation. The model package permits boiler heat transfer, fuels combustion, and pollutant emissions predictions related to a number of practical boiler operations such as fuel-switching, fuels co-firing, and reburning NO{sub x} reductions. The models are adaptable to most boiler/combustor designs and can handle burner fuels in solid, liquid, gaseous, and slurried forms. The models are also capable of performing predictions for combustion applications involving gaseous-fuel reburning, and co-firing of solid/gas, liquid/gas, gas/gas, slurry/gas fuels. The model package is conveniently named as BPACK (Boiler Package) and consists of six computer codes, of which three of them are main computational codes and the other three are input codes. The three main codes are: (a) a two-dimensional furnace heat-transfer and combustion code: (b) a detailed chemical-kinetics code; and (c) a boiler convective passage code. This user`s manual presents the computer model package in two volumes. Volume 1 describes in detail a number of topics which are of general users` interest, including the physical and chemical basis of the models, a complete description of the model applicability, options, input/output, and the default inputs. Volume 2 contains a detailed record of the worked examples to assist users in applying the models, and to illustrate the versatility of the codes.

  1. 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,...

  2. Engineering bed models for solid fuel conversion process in grate-fired boilers

    DEFF Research Database (Denmark)

    Costa, M.; Massarotti, N.; Indrizzi, V.

    2014-01-01

    of the syngas predicted by the two models is equal to about 7%. The application to different types of biomass shows that the difference in the predictions increases as the carbon content grows. The phenomenological model, in fact, generally considers higher conversion rates of this element to volatiles......A comparison between two numerical models describing the thermo-chemical conversion process of a solid fuel bed in a grate-fired boiler is presented. Both models consider the incoming biomass as subjected to drying, pyrolysis, gasification and combustion. In the first approach the biomass bed...... is treated as a 0D system, where the thermo-chemical processes are divided in two successive sections: drying and conversion. Phenomenological laws are written to characterize the syngas release as a function of the main governing parameters. The second model is an empirical 1D approach. Temperature, species...

  3. Bed models for solid fuel conversion process in grate-fired boilers

    DEFF Research Database (Denmark)

    Costa, M.; Massarotti, N.; Indrizzi, V.

    2013-01-01

    -chemical processes are divided in two successive sections: drying and conversion (which includes pyrolysis, gasification and combustion). The second model is an empirical 1D approach. The two models need input data such as composition, temperature and feeding rate of biomass and primary air. Temperature, species...... to describe the thermo-chemical conversion process of a solid fuel bed in a grate-fired boiler is presented. In this work both models consider the incoming solid fuel as subjected to drying, pyrolysis, gasification and combustion. In the first approach the biomass bed is treated as a 0D system, but the thermo...... concentrations and velocity of the producer gas leaving the fuel bed provided by the two models are compared. A sensitivity analysis with respect to mass flow rate of the primary air is also performed, as well as a further comparison regarding the dependence of the producer gas properties on the initial moisture...

  4. 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)

    Gruber, Thomas; Scharler, Robert; Obernberger, Ingwald

    2015-01-01

    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

  5. Hybrid model predictive control applied to switching control of burner load for a compact marine boiler design

    DEFF Research Database (Denmark)

    Solberg, Brian; Andersen, Palle; Maciejowski, Jan

    2008-01-01

    This paper discusses the application of hybrid model predictive control to control switching between different burner modes in a novel compact marine boiler design. A further purpose of the present work is to point out problems with finite horizon model predictive control applied to systems for w...

  6. Computational fluid dynamics (CFD) modelling of coal/biomass co-firing in pulverised fuel boilers

    Energy Technology Data Exchange (ETDEWEB)

    Moghtaderi, B.; Meesri, C. [University of Newcastle, Callaghan, NSW (Australia). CRC for Coal in Sustainable Development, Dept. of Chemical Engineering

    2002-07-01

    The present study is concerned with computational fluid dynamics (CFD) modelling of coal/biomass blends co-fired under conditions pertinent to pulverised fuel (PF) boilers. The attention is particularly focused on the near burner zone to examine the impact of biomass on the flame geometry and temperature. The predictions are obtained by numerical solution of the conservation equations for the gas and particle phases. The gas phase is solved in the Eulerian domain using steady-state time-averaged Navier-Stokes equations while the solution of the particle phase is obtained from a series of Lagrangian particle tracking equations. Turbulence is modelled using the {kappa}-{epsilon} and Reynolds Stress models. The comparison between the predictions and experimental measurement reported in the literature resulted in a good agreement. Other influences of biomass co-firing are observed for fuel devolatilisation and burnout. 19 refs., 6 figs.

  7. Distributed parameter modeling and simulation for the evaporation system of a controlled circulation boiler based on 3-D combustion monitoring

    International Nuclear Information System (INIS)

    Chu Yuntao; Lou Chun; Cheng Qiang; Zhou Huaichun

    2008-01-01

    In this paper, a dynamic, distributed parameter model for the evaporation system of a controlled circulation boiler was developed. As an essential basis, the 3-D temperature distribution and the average emissivity of the particle phase inside its furnace can be got by a flame image processing technique from multiple, visible flame image detectors in a real-time combustion monitoring system. Then the transient, 2-D radiation flux can be obtained by solving a set of energy balance equations for the water wall elements, which serves as a distributed boundary condition for the dynamic, distributed parameter model proposed for the evaporation system. For large change of the boiler load, two important parameters, the correction factor of equivalent flame emissivity and the coefficient of the steam mass flow rate at the outlet of the drum, were determined using the operation data from a 300 MW boiler. The model was validated by comparing the simulation results for some main steam parameters of the system with those from measurements. Besides that, the transient distributions of the parameters, such as the steam quality and the mass velocity, were predicted by the model. This model can be used for on-line calculation or off-line prediction of the local abnormal phenomena occurring on the water walls, forming an important basis to effectively evaluate the security and the reliability of a power plant boiler

  8. 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.

  9. Monitoring energy efficiency of condensing boilers via hybrid first-principle modelling and estimation

    NARCIS (Netherlands)

    Satyavada, Harish; Baldi, S.

    2018-01-01

    The operating principle of condensing boilers is based on exploiting heat from flue gases to pre-heat cold water at the inlet of the boiler: by condensing into liquid form, flue gases recover their latent heat of vaporization, leading to 10–12% increased efficiency with respect to traditional

  10. HR boiler

    Energy Technology Data Exchange (ETDEWEB)

    1982-08-01

    A number of manufacturers of central heating boilers in the Netherlands have produced high-efficiency boilers, all carrying the GIVEG-HR seal of approval (GIVEG is the manufacturers' association in the Netherlands, and HR stands for 'hoog rendement': high efficiency). Efficiences were considerably improved by reducing flue, idling and radiation losses. Control and safety, discharges of flue gases and condensate need special attention. Whether installation of a GIVEG-HR boiler is profitable in view of the cost/profit ratio, will have to be determined from case to case. N.V. Nederlandse Gasunie felt it was time to present the facts so far in a way specially aimed at the construction industry. This special edition of 'Gas and Architecture' answers a number of questions which the architect or consultant engineer might have in particular before advising on the installation of the new boiler in houses and other buildings in the interests of energy saving. A technical description of the HR boiler covers the backgrounds of its development and considers the role of the Netherlands government as regards to the introduction of the boiler.

  11. Study of connected system of automatic control of load and operation efficiency of a steam boiler with extremal controller on a simulation model

    Science.gov (United States)

    Sabanin, V. R.; Starostin, A. A.; Repin, A. I.; Popov, A. I.

    2017-02-01

    The problems of operation effectiveness increase of steam boilers are considered. To maintain the optimum fuel combustion modes, it is proposed to use an extremal controller (EC) determining the value of airflow rate, at which the boiler generating the desired amount of heat will consume a minimum amount of fuel. EC sets the determined value of airflow rate to airflow rate controller (ARC). The test results of numerical simulation dynamic nonlinear model of steam boiler with the connected system of automatic control of load and combustion efficiency using EC are presented. The model is created in the Simulink modeling package of MATLAB software and can be used to optimize the combustion modes. Based on the modeling results, the conclusion was drawn about the possibility in principle of simultaneously boiler load control and optimizing by EC the combustion modes when changing the fuel combustion heat and the boiler characteristics and its operating mode. It is shown that it is possible to automatically control the operation efficiency of steam boilers when using EC without applying the standard flue gas analyzers. The article considers the numerical simulation dynamic model of steam boiler with the schemes of control of fuel consumption and airflow rate, the steam pressure and EC; the purpose of using EC in the scheme with linear controllers and the requirements to the quality of its operation; the results of operation of boiler control schemes without EC with estimation of influence of roughness of thermal mode maps on the nature of static and dynamic connection of the control units of fuel consumption and airflow rate; the phase trajectories and the diagrams of transient processes occurring in the control scheme with EC with stepped changing the fuel quality and boiler characteristics; analysis of modeling results and prospects for using EC in the control schemes of boilers.

  12. Efficiency assessment of bi-radiated screens and improved convective set of tubes during the modernization of PTVM-100 tower hot-water boiler based on controlled all-mode mathematic models of boilers on Boiler Designer software

    Science.gov (United States)

    Orumbayev, R. K.; Kibarin, A. A.; Khodanova, T. V.; Korobkov, M. S.

    2018-03-01

    This work contains analysis of technical values of tower hot-water boiler PTVM-100 when operating on gas and oil residual. After the test it became clear that due to the construction deficiency during the combustion of oil residual, it is not possible to provide long-term production of heat. There is also given a short review on modernization of PTVM-100 hot-water boilers. With the help of calculations based on controlled all-mode mathematic modules of hot-water boilers in BOILER DESIGNER software, it was shown that boiler modernization by use of bi-radiated screens and new convective set of tubes allows decreasing sufficiently the temperature of combustor output gases and increase reliability of boiler operation. Constructive changes of boiler unit suggested by authors of this work, along with increase of boiler’s operation reliability also allow to improve it’s heat production rates and efficiency rate up to 90,5% when operating on fuel oil and outdoor installation option.

  13. A dynamic model used for controller design of a coal fired once-through boiler-turbine unit

    International Nuclear Information System (INIS)

    Liu, Ji-Zhen; Yan, Shu; Zeng, De-Liang; Hu, Yong; Lv, You

    2015-01-01

    Supercritical OTB (once-through boiler) units with high steam temperature and pressure have been widely used in modern power plants due to their high cycle efficiency and less emissions. To ensure the effective operation of such power generation systems, it is necessary to build a model for the design of the overall control system. There are already detailed models of once-through boilers; however, their complexity prevents them from being applied in the controller design. This study describes a lumped parameter dynamic model that has a relatively low complexity while faithfully capturing the essential overall plant dynamics. The model structure was derived by fundamental physical laws utilizing reasonable simplifications and data analysis to avoid the phase transition position problem. Parameter identification for the model structure was completed using operational data from a 1000 MW ultra-supercritical OTB. The model was determined to be reasonable by comparison tests between computed data and measured data for both steady and dynamic states. The simplified model is verified to have appropriate fidelity in control system design to achieve effective and economic operation of the unit. - Highlights: • A simplified dynamic model of once-through boiler-turbine unit is given. • The essential dynamics of active power and throttle pressure is presented. • The change of phase transition position is avoided in modeling process. • The model has appropriate complexity and fidelity for controller design.

  14. Sootblowing optimization for improved boiler performance

    Science.gov (United States)

    James, John Robert; McDermott, John; Piche, Stephen; Pickard, Fred; Parikh, Neel J.

    2012-12-25

    A sootblowing control system that uses predictive models to bridge the gap between sootblower operation and boiler performance goals. The system uses predictive modeling and heuristics (rules) associated with different zones in a boiler to determine an optimal sequence of sootblower operations and achieve boiler performance targets. The system performs the sootblower optimization while observing any operational constraints placed on the sootblowers.

  15. Statistical modeling of an integrated boiler for coal fired thermal power plant

    Directory of Open Access Journals (Sweden)

    Sreepradha Chandrasekharan

    2017-06-01

    Full Text Available The coal fired thermal power plants plays major role in the power production in the world as they are available in abundance. Many of the existing power plants are based on the subcritical technology which can produce power with the efficiency of around 33%. But the newer plants are built on either supercritical or ultra-supercritical technology whose efficiency can be up to 50%. Main objective of the work is to enhance the efficiency of the existing subcritical power plants to compensate for the increasing demand. For achieving the objective, the statistical modeling of the boiler units such as economizer, drum and the superheater are initially carried out. The effectiveness of the developed models is tested using analysis methods like R2 analysis and ANOVA (Analysis of Variance. The dependability of the process variable (temperature on different manipulated variables is analyzed in the paper. Validations of the model are provided with their error analysis. Response surface methodology (RSM supported by DOE (design of experiments are implemented to optimize the operating parameters. Individual models along with the integrated model are used to study and design the predictive control of the coal-fired thermal power plant. Keywords: Chemical engineering, Applied mathematics

  16. Statistical modeling of an integrated boiler for coal fired thermal power plant.

    Science.gov (United States)

    Chandrasekharan, Sreepradha; Panda, Rames Chandra; Swaminathan, Bhuvaneswari Natrajan

    2017-06-01

    The coal fired thermal power plants plays major role in the power production in the world as they are available in abundance. Many of the existing power plants are based on the subcritical technology which can produce power with the efficiency of around 33%. But the newer plants are built on either supercritical or ultra-supercritical technology whose efficiency can be up to 50%. Main objective of the work is to enhance the efficiency of the existing subcritical power plants to compensate for the increasing demand. For achieving the objective, the statistical modeling of the boiler units such as economizer, drum and the superheater are initially carried out. The effectiveness of the developed models is tested using analysis methods like R 2 analysis and ANOVA (Analysis of Variance). The dependability of the process variable (temperature) on different manipulated variables is analyzed in the paper. Validations of the model are provided with their error analysis. Response surface methodology (RSM) supported by DOE (design of experiments) are implemented to optimize the operating parameters. Individual models along with the integrated model are used to study and design the predictive control of the coal-fired thermal power plant.

  17. Experimental investigation of stresses and deformations of the model of a pod-boiler-prestressed concrete pressure vessel. Pt. 1

    International Nuclear Information System (INIS)

    Stoever, R.

    1973-01-01

    Investigations of elastic models are suitable to obtain independent values for stress states and deformations of thickwalled pressure vessels to check computer programs for three-dimensional elastic calculations. An elastic model of epoxy resin was constructed with the geometry of the pod boiler pressure vessel of the Hartlepool nuclear power station. With this model strains and deformations were measured for internal pressure. The stress states in the neighbourhood of the large vertical openings for the boiler pods and the horizontal gas ducts and at the junction of cylinder and plates were of special interest. Therefore most of the gauges were concentrated in these regions. A considerable number of strain gauges were embedded in the wall. The construction of the model is described in part one and results of the measurements are presented and discussed in part two of this report. (orig.) [de

  18. Realization of BP neural network modeling based on NOXof CFB boiler in DCS

    Science.gov (United States)

    Bai, Jianyun; Zhu, Zhujun; Wang, Qi; Ying, Jiang

    2018-02-01

    In the CFB boiler installed with SNCR denitrification system, the mass concentration of NO X is difficult to be predicted by the conventional mathematical model, and the step response mathematical model, obtained by using the step disturbance test of ammonia injection,is inaccurate. this paper presents two kinds of BP neural network model, according to the relationship between the generated mass concentration of NO X and the load, the ratio of air to coal without using the SNCR system, as well as the relationship between the tested mass concentration of NO X and the load, the ratio of air to coal and the amount of ammonia using the SNCR system. then itrealized the on-line prediction of the mass concentration of NO X and the remaining mass concentration of NO X after reductionreaction in DCS system. the practical results show that the average error per hour between generation and the prediction of the amount of NO X mass concentration is within 10 mg/Nm3,the reducing reaction of measured and predicted hourly average error is within 2 mg/Nm3, all in error range, which provides a more accurate model for solvingthe problem on NO X automatic control of SNCR system.

  19. Utility boiler computer modeling experience in the USA for practical furnace air port and low NOx burner field design

    Energy Technology Data Exchange (ETDEWEB)

    Breen, B.P.; Urich, J.A.; Krippene, B.C. [ESA, Inc. (United States)

    2000-07-01

    This paper presents several examples of where effective furnace and low NOx burner modeling has produced substantial advantages to the low NOx combustion system designer. Using practical boiler furnace air injection port and low NOx burner maths modeling as an integral part of the design process has often made the difference between a successful low NOx combustion system field conversion project and an unsuccessful one.

  20. Efficient boiler operations sourcebook

    Energy Technology Data Exchange (ETDEWEB)

    Payne, F.W. (comp.)

    1985-01-01

    This book emphasizes the practical aspects of industrial and commercial boiler operations. It starts with a comprehensive review of general combustion and boiler fundamentals and then deals with specific efficiency improvement methods, and the cost savings which result. The book has the following chapter headings: boiler combustion fundamentals; boiler efficiency goals; major factors controlling boiler efficiency; boiler efficiency calculations; heat loss; graphical solutions; preparation for boiler testing; boiler test procedures; efficiency-related boiler maintenance procedures; boiler tune-up; boiler operational modifications; effect of water side and gas side scale deposits; load management; auxillary equipment to increase boiler efficiency; air preheaters and economizers; other types of auxillary equipment; combustion control systems and instrumentation; boiler O/sub 2/ trim controls; should you purchase a new boiler.; financial evaluation procedures; case studies. The last chapter includes a case study of a boiler burning pulverized coal and a case study of stoker-fired coal.

  1. Theoretical development of a thermal model for the reheater of a power plant boiler

    Energy Technology Data Exchange (ETDEWEB)

    Prieto, M.M. [Oviedo University, Energy Department, Campus de Viesques, 33204 GIJON. Asturias (Spain)]. E-mail: manuelap@uniovi.es; Suarez, I. [Oviedo University, Energy Department, Campus de Viesques, 33204 GIJON. Asturias (Spain); Fernandez, F.J. [Oviedo University, Energy Department, Campus de Viesques, 33204 GIJON. Asturias (Spain); Sanchez, H. [Central Termica de Soto de Ribera, Ribera de Arriba, Asturias (Spain); Mateos, M. [Central Termica de Soto de Ribera, Ribera de Arriba, Asturias (Spain)

    2007-02-15

    A three-dimensional numerical model for simulating flow and heat transfer in the reheater of a boiler is presented. The aim is to describe, as well as possible, the geometry of the reheater and to be able to perform different mass flows of steam along each of the tube serpentines. The model thus makes it possible to calculate the temperature of the tube surfaces along the reheater. The porosity concept is employed, along with empirical correlations for the convective heat transfer coefficient and the radiation heat transfer coefficients. The radiation equations consider most of the radiative effects of the gas: ash content, triatomic gases, type of fuel and temperatures, tube layout and distances and temperatures of other radiative surfaces. The model is proposed with a view to using the measured values of velocities, temperatures and gas composition in the reheater as boundary conditions. The equations are solved using a general purpose computational fluid dynamics (CFD) code in conjunction with specific calculations for the source terms.

  2. Data-driven modeling and predictive control for boiler-turbine unit using fuzzy clustering and subspace methods.

    Science.gov (United States)

    Wu, Xiao; Shen, Jiong; Li, Yiguo; Lee, Kwang Y

    2014-05-01

    This paper develops a novel data-driven fuzzy modeling strategy and predictive controller for boiler-turbine unit using fuzzy clustering and subspace identification (SID) methods. To deal with the nonlinear behavior of boiler-turbine unit, fuzzy clustering is used to provide an appropriate division of the operation region and develop the structure of the fuzzy model. Then by combining the input data with the corresponding fuzzy membership functions, the SID method is extended to extract the local state-space model parameters. Owing to the advantages of the both methods, the resulting fuzzy model can represent the boiler-turbine unit very closely, and a fuzzy model predictive controller is designed based on this model. As an alternative approach, a direct data-driven fuzzy predictive control is also developed following the same clustering and subspace methods, where intermediate subspace matrices developed during the identification procedure are utilized directly as the predictor. Simulation results show the advantages and effectiveness of the proposed approach. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  3. Advanced CFD modelling of air and recycled flue gas staging in a waste wood-fired grate boiler for higher combustion efficiency and greater environmental benefits.

    Science.gov (United States)

    Rajh, Boštjan; Yin, Chungen; Samec, Niko; Hriberšek, Matjaž; Kokalj, Filip; Zadravec, Matej

    2018-07-15

    Grate-fired boilers are commonly used to burn biomass/wastes for heat and power production. In spite of the recent breakthrough in integration of advanced secondary air systems in grate boilers, grate-firing technology needs to be advanced for higher efficiency and lower emissions. In this paper, innovative staging of combustion air and recycled flue gas in a 13 MW th waste wood-fired grate boiler is comprehensively studied based on a numerical model that has been previously validated. In particular, the effects of the jet momentum, position and orientation of the combustion air and recycled flue gas streams on in-furnace mixing, combustion and pollutant emissions from the boiler are examined. It is found that the optimized air and recycled flue gas jets remarkably enhance mixing and heat transfer, result in a more uniform temperature and velocity distribution, extend the residence time of the combustibles in the hot zone and improve burnout in the boiler. Optimizing the air and recycled flue gas jet configuration can reduce carbon monoxide emission from the boiler by up to 86%, from the current 41.0 ppm to 5.7 ppm. The findings of this study can serve as useful guidelines for novel design and optimization of the combustion air supply and flue gas recycling for grate boilers of this type. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Electric Boiler and Heat Pump Thermo-Electrical Models for Demand Side Management Analysis in Low Voltage Grids

    DEFF Research Database (Denmark)

    Diaz de Cerio Mendaza, Iker; Bak-Jensen, Birgitte; Chen, Zhe

    2013-01-01

    The last fifteen years many European countries have integrated large percentage of renewable energy on their electricity generation mix. In Denmark the 21.3% of the electricity consumed nowadays is produced by the wind, and it has planned to be the 50% by 2025. In order to front future challenges...... on the power system control and operation, created by this unstable way of generation, Demand Side Management turns to be a promising solution. The storage capacity from thermo-electric units, like electric boilers and heat pumps, allows operating them with certain freedom. Hence they can be employed under...... certain coordination, to actively respond to the power system fluctuations. The following paper presents two simple thermo-electrical models of an electrical boiler and an air-source CO2 heat pump system. The purpose is using them in low voltage grids analysis to assess their capacity and flexibility...

  5. Application of zonal combustion model for on-line furnace analysis of 575MW tangential coal firing boiler

    Energy Technology Data Exchange (ETDEWEB)

    Chudnovsky, B.; Karasina, E.; Livshits, B.; Talanker, A. [Israel Electric Corporation (Israel). Engineering Division

    1999-07-01

    An advanced code for calculating heat transfer in the boiler of furnaces is considered. The code can be used to compute the flue gas temperature in the furnace volume and the absorbed and incident heat fluxes. The number of zones in the furnace, the points of the injection of the fuel, air and flue gas recirculation (if applicable), the radiative heat transfer properties of the flue gases as well as all the factors determining performance are taken into account in the calculation. The code also predicts water wall and superheater temperature and NO{sub x} emission. The validity of the proposed model was confirmed by comparison between calculated and measured values. The predicted results show good agreement with the experimental data. The code developed is for engineers using advanced PCS at the stage of designing new boilers as well as when retrofitting and adjusting boilers already in operation. In comparison with existing complex computational models the proposed system can be used in modern monitoring systems for the furnace diagnostic problems including NO{sub x} emission. 7 refs., 11 figs.

  6. Modeling N2O Reduction and Decomposition in a Circulating Fluidized bed Boiler

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Åmand, Lars-Erik; Dam-Johansen, Kim

    1996-01-01

    The N2O concentration was measured in a circulating fluidized bed boiler of commercial size. Kinetics for N2O reduction by char and catalytic reduction and decomposition over bed material from the combustor were determined in a laboratory fixed bed reactor. The destruction rate of N2O in the comb......The N2O concentration was measured in a circulating fluidized bed boiler of commercial size. Kinetics for N2O reduction by char and catalytic reduction and decomposition over bed material from the combustor were determined in a laboratory fixed bed reactor. The destruction rate of N2O...... in the combustion chamber and the cyclone was calculated taking three mechanisms into account: Reduction by char, catalytic decomposition over bed material and thermal decomposition. The calculated destruction rate was in good agreement with the measured destruction of N2O injected at different levels in the boiler...

  7. 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.

  8. Numerical Modeling of the Effect of Thawing of Soil in the Area of Placing Tanks for Storage Fuel of Thermal Power Plants and Boiler

    Directory of Open Access Journals (Sweden)

    Polovnikov V.Yu.

    2016-01-01

    Full Text Available This paper describes the numerical modeling of heat transfer in the area placing of the tank for storage fuel of thermal power plant and boiler with considering the influence of thawing of the soil. We have established that the thawing of the soil in the area of placing of the tank for storage fuel of thermal power plant and boiler have little effect on the change of heat loss.

  9. Towards a generic, reliable CFD modelling methodology for waste-fired grate boilers

    DEFF Research Database (Denmark)

    Rajh, Boštjan; Yin, Chungen; Samec, Niko

    of the increased CO2 and H2O vapour concentrations on radiative heat transfer in the boiler. The impacts of full buoyancy on turbulence are also investigated. As a validation effort, the temperature profiles at different ports inside the furnace are measured and the experimental values are compared with the CFD...

  10. ENERGY STAR Certified Commercial Boilers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 1.0 ENERGY STAR Program Requirements for Commercial Boilers that are effective as of...

  11. Investigation of a Boiler's Furnace Aerodynamics with a Vortex Solid Fuel Combustion Scheme on Physical and Mathematical Models

    Directory of Open Access Journals (Sweden)

    Prokhorov V.B.,

    2018-04-01

    Full Text Available The important problem of developing the low-cost technologies that will be able to provide a deep decrease in the concentration of nitrogen oxides while maintaining fuel burn-up efficiency is considered. This paper presents the results of the aerodynamics study of the furnace of boiler TPP-210A on the base of the physical and mathematical models in the case when boiler retrofitting from liquid to solid slag removal with two to three times reduction of nitrogen oxide emissions and replacing the vortex burners with direct-flow burners. The need for these studies is due to the fact that the direct-flow burners are "collective action" burners, and efficient fuel combustion can be provided only by the interaction of fuel jets, secondary and tertiary air jets in the furnace volume. The new scheme of air staged combustion in a system of vertical vortexes of opposite rotation with direct-flow burners and nozzles and direct injection of Kuznetsky lean coal dust was developed. In order to test the functional ability and efficiency of the proposed combustion scheme, studies on the physical model of the boiler furnace and the mathematical model of the experimental furnace bench for the case of an isothermal fluid flow were carried out. Comparison showed an acceptable degree of coincidence of these results. In all studied regimes, pronounced vortices remain in both the vertical and horizontal planes, that indicates a high degree of mass exchange between jets and combustion products and the furnace aerodynamics stability to changes in regime factors.

  12. Proportional hazards models of infrastructure system recovery

    International Nuclear Information System (INIS)

    Barker, Kash; Baroud, Hiba

    2014-01-01

    As emphasis is being placed on a system's ability to withstand and to recover from a disruptive event, collectively referred to as dynamic resilience, there exists a need to quantify a system's ability to bounce back after a disruptive event. This work applies a statistical technique from biostatistics, the proportional hazards model, to describe (i) the instantaneous rate of recovery of an infrastructure system and (ii) the likelihood that recovery occurs prior to a given point in time. A major benefit of the proportional hazards model is its ability to describe a recovery event as a function of time as well as covariates describing the infrastructure system or disruptive event, among others, which can also vary with time. The proportional hazards approach is illustrated with a publicly available electric power outage data set

  13. Numerical investigation of a straw combustion boiler – Part I: Modelling of the thermo-chemical conversion of straw

    Directory of Open Access Journals (Sweden)

    Dernbecher Andrea

    2016-01-01

    Full Text Available In the framework of a European project, a straw combustion boiler in conjunction with an organic Rankine cycle is developed. One objective of the project is the enhancement of the combustion chamber by numerical methods. A comprehensive simulation of the combustion chamber is prepared, which contains the necessary submodels for the thermo-chemical conversion of straw and for the homogeneous gas phase reactions. Part I introduces the modelling approach for the thermal decomposition of the biomass inside the fuel bed, whereas part II deals with the simulation of the gas phase reactions in the freeboard.

  14. Thermodynamic analysis and kinetic modelling of dioxin formation and emissions from power boilers firing salt-laden hog fuel.

    Science.gov (United States)

    Duo, Wenli; Leclerc, Denys

    2007-04-01

    Both organic chlorine (e.g. PVC) and inorganic chlorides (e.g. NaCl) can be significant chlorine sources for dioxin and furan (PCDD/F) formation in combustion processes. This paper presents a thermodynamic analysis of high temperature salt chemistry. Its influence on PCDD/F formation in power boilers burning salt-laden wood waste is examined through the relationships between Cl2, HCl, NaCl(g) and NaCl(c). These analyses show that while HCl is a product of combustion of PVC-laden municipal solid waste, NaCl can be converted to HCl in hog fuel boilers by reactions with SO2 or alumino-silicate materials. Cl2 is a strong chlorinating agent for PCDD/F formation. HCl can be oxidized to Cl2 by O2, and Cl2 can be reduced back to HCl by SO2. The presence of sulphur at low concentrations thus enhances PCDD/F formation by increasing HCl concentrations. At high concentrations, sulphur inhibits de novo formation of PCDD/Fs through Cl2 reduction by excess SO2. The effect of NH3, CO and NOx on PCDD/F formation is also discussed. A semi-empirical kinetic model is proposed. This model considers both precursor and de novo formation mechanisms. A simplified version is used as a stack emission model. The kinetic model indicates that stack dioxin emissions will increase linearly with decreasing electrostatic precipitator (ESP) efficiency and exponentially with increasing ESP temperature.

  15. Linear modeling of nonlinear systems using artificial neural networks based on I/O data and its application in power plant boiler modeling

    International Nuclear Information System (INIS)

    Ghaffari, A.; Nikkhah Bahrami, M.; Mohammadzaheri, M.

    2005-01-01

    In this paper a new method for linear modeling of nonlinear systems is presented. The method is based on the design of an artificial neural network with two layers. The network is trained only according to the input-output data of the system. The weights of connections in this network, represents the coefficients of the transfer function. For systems with linear behavior the method of least square error represents the best linear model of the system. However, for nonlinear systems, such as some subsystems in power plants boilers LSE does not represent the best linear approximation of the system, necessarily. In this paper a new linear modeling method is presented and applied to some subsystems in a power plant boiler. Comparison between the transfer function obtained in this way and by least square error method,shows that the neural network method gives better linear models for these nonlinear systems

  16. An overview of CFD modelling of small-scale fixed-bed biomass pellet boilers with preliminary results from a simplified approach

    International Nuclear Information System (INIS)

    Chaney, Joel; Liu Hao; Li Jinxing

    2012-01-01

    Highlights: ► Overview of the overall approach of modelling fixed-bed biomass boilers in CFD. ► Bed sub-models of moisture evaporation, devolatisation and char combustion reviewed. ► A method of embedding a combustion model in discrete fuel zones within the CFD is suggested. ► Includes sample of preliminary results for a 50 kW pellet boiler. ► Clear physical trends predicted. - Abstract: The increasing global energy demand and mounting pressures for CO 2 mitigation call for increased efficient utilization of biomass, particularly for heating domestic and commercial buildings. The authors of the present paper are investigating the optimization of the combustion performance and NO x emissions of a 50 kW biomass pellet boiler fabricated by a UK manufacturer. The boiler has a number of adjustable parameters including the ratio of air flow split between the primary and secondary supplies, the orientation, height, direction and number of the secondary inlets. The optimization of these parameters provides opportunities to improve both the combustion efficiency and NO x emissions. When used carefully in conjunction with experiments, Computational Fluid Dynamics (CFD) modelling is a useful tool for rapidly and at minimum cost examining the combustion performance and emissions from a boiler with multiple variable parameters. However, modelling combustion and emissions of a small-scale biomass pellet boiler is not trivial and appropriate fixed-bed models that can be coupled with the CFD code are required. This paper reviews previous approaches specifically relevant to simulating fixed-bed biomass boilers. In the first part it considers approaches to modelling the heterogeneous solid phase and coupling this with the gas phase. The essential components of the sub-models are then overviewed. Importantly, for the optimization process a model is required that has a good balance between accuracy in predicting physical trends, with low computational run time. Finally, a

  17. Dynamic simulation of a circulating fluidized bed boiler system part I: Description of the dynamic system and transient behavior of sub-models

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Il; Choi, Sang Min; Yang, Jong In [Dept. of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2016-12-15

    Dynamic performance simulation of a CFB boiler in a commercial-scale power plant is reported. The boiler system was modeled by a finite number of heat exchanger units, which are sub-grouped into the gas-solid circulation loop, the water-steam circulation loop, and the inter-connected heat exchangers blocks of the boiler. This dynamic model is an extension from the previously reported performance simulation model, which was designed to simulate static performance of the same power plant, where heat and mass for each of the heat exchanger units were balanced for the inter-connected heat exchanger network among the fuel combustion system and the water-steam system. Dynamic performance simulation was achieved by calculating the incremental difference from the previous time step, and progressing for the next time step. Additional discretization of the heat exchanger blocks was necessary to accommodate the dynamic response of the water evaporation and natural circulation as well as the transient response of the metal temperature of the heat exchanger elements. Presentation of the simulation modeling is organized into two parts; system configuration of the model plant and the general approach of the simulation are presented along with the transient behavior of the sub-models in Part I. Dynamic sub-models were integrated in terms of the mass flow and the heat transfer for simulating the CFB boiler system. Dynamic simulation for the open loop response was performed to check the integrated system of the water-steam loop and the solid-gas loop of the total boiler system. Simulation of the total boiler system which includes the closed-loop control system blocks is presented in the following Part II.

  18. Dynamic simulation of a circulating fluidized bed boiler system part I: Description of the dynamic system and transient behavior of sub-models

    International Nuclear Information System (INIS)

    Kim, Seong Il; Choi, Sang Min; Yang, Jong In

    2016-01-01

    Dynamic performance simulation of a CFB boiler in a commercial-scale power plant is reported. The boiler system was modeled by a finite number of heat exchanger units, which are sub-grouped into the gas-solid circulation loop, the water-steam circulation loop, and the inter-connected heat exchangers blocks of the boiler. This dynamic model is an extension from the previously reported performance simulation model, which was designed to simulate static performance of the same power plant, where heat and mass for each of the heat exchanger units were balanced for the inter-connected heat exchanger network among the fuel combustion system and the water-steam system. Dynamic performance simulation was achieved by calculating the incremental difference from the previous time step, and progressing for the next time step. Additional discretization of the heat exchanger blocks was necessary to accommodate the dynamic response of the water evaporation and natural circulation as well as the transient response of the metal temperature of the heat exchanger elements. Presentation of the simulation modeling is organized into two parts; system configuration of the model plant and the general approach of the simulation are presented along with the transient behavior of the sub-models in Part I. Dynamic sub-models were integrated in terms of the mass flow and the heat transfer for simulating the CFB boiler system. Dynamic simulation for the open loop response was performed to check the integrated system of the water-steam loop and the solid-gas loop of the total boiler system. Simulation of the total boiler system which includes the closed-loop control system blocks is presented in the following Part II

  19. Modeling and sliding mode predictive control of the ultra-supercritical boiler-turbine system with uncertainties and input constraints.

    Science.gov (United States)

    Tian, Zhen; Yuan, Jingqi; Zhang, Xiang; Kong, Lei; Wang, Jingcheng

    2018-05-01

    The coordinated control system (CCS) serves as an important role in load regulation, efficiency optimization and pollutant reduction for coal-fired power plants. The CCS faces with tough challenges, such as the wide-range load variation, various uncertainties and constraints. This paper aims to improve the load tacking ability and robustness for boiler-turbine units under wide-range operation. To capture the key dynamics of the ultra-supercritical boiler-turbine system, a nonlinear control-oriented model is developed based on mechanism analysis and model reduction techniques, which is validated with the history operation data of a real 1000 MW unit. To simultaneously address the issues of uncertainties and input constraints, a discrete-time sliding mode predictive controller (SMPC) is designed with the dual-mode control law. Moreover, the input-to-state stability and robustness of the closed-loop system are proved. Simulation results are presented to illustrate the effectiveness of the proposed control scheme, which achieves good tracking performance, disturbance rejection ability and compatibility to input constraints. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

  20. Model Research of Gas Emissions From Lignite and Biomass Co-Combustion in a Large Scale CFB Boiler

    Directory of Open Access Journals (Sweden)

    Krzywański Jarosław

    2014-06-01

    Full Text Available The paper is focused on the idea of a combustion modelling of a large-scale circulating fluidised bed boiler (CFB during coal and biomass co-combustion. Numerical computation results for three solid biomass fuels co-combustion with lignite are presented in the paper. The results of the calculation showed that in previously established kinetics equations for coal combustion, some reactions had to be modified as the combustion conditions changed with the fuel blend composition. Obtained CO2, CO, SO2 and NOx emissions are located in borders of ± 20% in the relationship to the experimental data. Experimental data was obtained for forest biomass, sunflower husk, willow and lignite cocombustion tests carried out on the atmospheric 261 MWe COMPACT CFB boiler operated in PGE Turow Power Station in Poland. The energy fraction of biomass in fuel blend was: 7%wt, 10%wt and 15%wt. The measured emissions of CO, SO2 and NOx (i.e. NO + NO2 were also shown in the paper. For all types of biomass added to the fuel blends the emission of the gaseous pollutants was lower than that for coal combustion.

  1. A comparison of fuzzy logic and cluster renewal approaches for heat transfer modeling in a 1296 t/h CFB boiler with low level of flue gas recirculation

    Directory of Open Access Journals (Sweden)

    Błaszczuk Artur

    2017-03-01

    Full Text Available The interrelation between fuzzy logic and cluster renewal approaches for heat transfer modeling in a circulating fluidized bed (CFB has been established based on a local furnace data. The furnace data have been measured in a 1296 t/h CFB boiler with low level of flue gas recirculation. In the present study, the bed temperature and suspension density were treated as experimental variables along the furnace height. The measured bed temperature and suspension density were varied in the range of 1131-1156 K and 1.93-6.32 kg/m3, respectively. Using the heat transfer coefficient for commercial CFB combustor, two empirical heat transfer correlation were developed in terms of important operating parameters including bed temperature and also suspension density. The fuzzy logic results were found to be in good agreement with the corresponding experimental heat transfer data obtained based on cluster renewal approach. The predicted bed-to-wall heat transfer coefficient covered a range of 109-241 W/(m2K and 111-240 W/(m2K, for fuzzy logic and cluster renewal approach respectively. The divergence in calculated heat flux recovery along the furnace height between fuzzy logic and cluster renewal approach did not exceeded ±2%.

  2. Dynamic Simulation of an Organic Rankine Cycle—Detailed Model of a Kettle Boiler

    Directory of Open Access Journals (Sweden)

    Roberto Pili

    2017-04-01

    Full Text Available Organic Rankine Cycles (ORCs are nowadays a valuable technology to produce electricity from low and medium temperature heat sources, e.g., in geothermal, biomass and waste heat recovery applications. Dynamic simulations can help improve the flexibility and operation of such plants, and guarantee a better economic performance. In this work, a dynamic model for a multi-pass kettle evaporator of a geothermal ORC power plant has been developed and its dynamics have been validated against measured data. The model combines the finite volume approach on the tube side and a two-volume cavity on the shell side. To validate the dynamic model, a positive and a negative step function in heat source flow rate is applied. The simulation model performed well in both cases. The liquid level appeared the most challenging quantity to simulate. A better agreement in temperature was achieved by increasing the volume flow rate of the geothermal brine by 2% over the entire simulation. Measurement errors, discrepancies in working fluid and thermal brine properties and uncertainties in heat transfer correlations can account for this. In the future, the entire geothermal power plant will be simulated, and suggestions to improve its dynamics and control by means of simulations will be provided.

  3. Survivability Assessment: Modeling A Recovery Process

    OpenAIRE

    Paputungan, Irving Vitra; Abdullah, Azween

    2009-01-01

    Survivability is the ability of a system to continue operating, in a timely manner, in the presence ofattacks, failures, or accidents. Recovery in survivability is a process of a system to heal or recover from damageas early as possible to fulfill its mission as condition permit. In this paper, we show a preliminary recoverymodel to enhance the system survivability. The model focuses on how we preserve the system and resumes itscritical service under attacks as soon as possible.Keywords: surv...

  4. A novel least squares support vector machine ensemble model for NOx emission prediction of a coal-fired boiler

    International Nuclear Information System (INIS)

    Lv, You; Liu, Jizhen; Yang, Tingting; Zeng, Deliang

    2013-01-01

    Real operation data of power plants are inclined to be concentrated in some local areas because of the operators’ habits and control system design. In this paper, a novel least squares support vector machine (LSSVM)-based ensemble learning paradigm is proposed to predict NO x emission of a coal-fired boiler using real operation data. In view of the plant data characteristics, a soft fuzzy c-means cluster algorithm is proposed to decompose the original data and guarantee the diversity of individual learners. Subsequently the base LSSVM is trained in each individual subset to solve the subtask. Finally, partial least squares (PLS) is applied as the combination strategy to eliminate the collinear and redundant information of the base learners. Considering that the fuzzy membership also has an effect on the ensemble output, the membership degree is added as one of the variables of the combiner. The single LSSVM and other ensemble models using different decomposition and combination strategies are also established to make a comparison. The result shows that the new soft FCM-LSSVM-PLS ensemble method can predict NO x emission accurately. Besides, because of the divide and conquer frame, the total time consumed in the searching the parameters and training also decreases evidently. - Highlights: • A novel LSSVM ensemble model to predict NO x emissions is presented. • LSSVM is used as the base learner and PLS is employed as the combiner. • The model is applied to process data from a 660 MW coal-fired boiler. • The generalization ability of the model is enhanced. • The time consuming in training and searching the parameters decreases sharply

  5. Increase of energy efficiency in proportional adjusting of flow rate in the boiler circuit

    OpenAIRE

    Artamonov Pavel A.; Kurilenko Nikolai I.; Mamontov Gennady Ya.

    2017-01-01

    The article presents the results of theoretical studies in the field of the boiler circuit operating modes for the boiler rooms operating by the independent heat supply scheme. The 3D model of a boiler circuit for a boiler room with 3 MW rated output was developed, based on which there was made an estimation of the boiler pump performance indicators. There is proposed a method for reducing energy costs for the operation of the pumping equipment of the boiler circuit.

  6. Chemical cleaning of UK AGR boilers

    International Nuclear Information System (INIS)

    Rudge, A.; Turner, P.; Ghosh, A.; Clary, W.; Tice, D.

    2002-01-01

    For the first time in their operational lives, UK advanced gas-cooled reactor once-through boilers have been chemically cleaned. Chemical cleaning was necessary to avoid lost output resulting from boiler pressure drops, which had been increasing for a number of years. Chemical cleaning of these boilers presents a number of unique difficulties. These include lack of access to the boilers, highly sensitised 316H superheater sections that cannot be excluded from the cleaning flow path, relatively thin boiler tube walls and an intolerance to boiler tube failure because of the role of the boilers in nuclear decay heat removal. The difficulties were overcome by implementing the clean in a staged manner, starting with an extensive materials testwork programme to select and then to substantiate the cleaning process. The selected process was based on ammoniated citric acid plus formic acid for the principal acid cleaning stage. Materials testwork was followed by an in-plant trial clean of six boiler tubes, further materials testwork and the clean of a boiler tube in a full-scale test rig. An overview is presented of the work that was carried out to demonstrate that the clean could be carried out safely, effectively and without leading to unacceptable corrosion losses. Full-scale chemical cleaning was implemented by using as much of the existing plant as possible. Careful control and monitoring was employed to ensure that the cleaning was implemented according to the specified design, thus ensuring that a safe and effective clean was carried out. Full-scale cleaning has resulted in significant boiler pressure drop recovery, even though the iron burden was relatively low and cleaning was completed in a short time. (orig.)

  7. CFD modeling of ash deposition for co-combustion of MBM with coal in a tangentially fired utility boiler

    NARCIS (Netherlands)

    Taha, T.J.; Stam, A.F.; Stam, K.; Brem, Gerrit

    2013-01-01

    Ash deposition is one of the main challenges that needs to be tackled in response to increased percentage of biomass co-firing in pulverized fuel boilers. In this study, a model has been developed to investigate the slagging behavior of meat and bone meal (MBM) at higher co-firing rates in the

  8. Boilers, evaporators, and condensers

    International Nuclear Information System (INIS)

    Kakac, S.

    1991-01-01

    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

  9. Bio boiler - Control conditions. Part 1: Model development and analysis of operating conditions; Biokedel - Reguleringsmaessige forhold. Del 1: Modeludvikling og analyse af dynamiske driftsforhold

    Energy Technology Data Exchange (ETDEWEB)

    Boecher Poulsen, K.; Christensen, Torkild; Mortensen, Jan; Runge Kristoffersen, J.; Kristmundsson, E. [Tech-wise A/S (Denmark); Moekbak, T.; Mortensen, Hans Peter [Elsam A/S (Denmark)

    2002-12-15

    This report focuses on the model-building part of the PSO project, 'Control Conditions Bio-boiler'. In the project, which treats dynamic simulation of biomass fired power plants via the MMS software, a certain number of straw/wood chip modules have been built, together with a combustion module which, when connected to the existing MMS modules, can be used for dynamic simulation. Furthermore, a certain number of continuous and discrete components have been built which, together with the remaining MMS modules will create a complete model of the active part of the control structure under the most common operation conditions. By means of the developed straw, combustion and control modules, a model of Enstedvaerket's bio-boiler is built (without wood chip super-heater), including practically all auxiliary control mechanisms. In the report the primary problems caused by the development of the model are discussed, typically numerical problems. First of all it is discussed how a steady state condition can be reached from a nonphysical condition at the start-up of the simulation. After reaching a steady state condition at full load, the boiler load is reduced by adjusting the desired live steam flow setpoint value and the load gradient (as it would be done from the control room). While reducing to part load, one straw line is closed down, as it would be done in 'real life'. From part load, the boiler load is once again in the same way increased to full. (BA) The simulation results are then compared to measurements made on the same boiler during load reduction and load increase.

  10. Estimation of Scale Deposition in the Water Walls of an Operating Indian Coal Fired Boiler: Predictive Modeling Approach Using Artificial Neural Networks

    Science.gov (United States)

    Kumari, Amrita; Das, Suchandan Kumar; Srivastava, Prem Kumar

    2016-04-01

    Application of computational intelligence for predicting industrial processes has been in extensive use in various industrial sectors including power sector industry. An ANN model using multi-layer perceptron philosophy has been proposed in this paper to predict the deposition behaviors of oxide scale on waterwall tubes of a coal fired boiler. The input parameters comprises of boiler water chemistry and associated operating parameters, such as, pH, alkalinity, total dissolved solids, specific conductivity, iron and dissolved oxygen concentration of the feed water and local heat flux on boiler tube. An efficient gradient based network optimization algorithm has been employed to minimize neural predictions errors. Effects of heat flux, iron content, pH and the concentrations of total dissolved solids in feed water and other operating variables on the scale deposition behavior have been studied. It has been observed that heat flux, iron content and pH of the feed water have a relatively prime influence on the rate of oxide scale deposition in water walls of an Indian boiler. Reasonably good agreement between ANN model predictions and the measured values of oxide scale deposition rate has been observed which is corroborated by the regression fit between these values.

  11. 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.

  12. Developing Boiler Concepts as Integrated Units

    DEFF Research Database (Denmark)

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

    2004-01-01

    - 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......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......, emissions and to obtain long time operation experiences with the boiler concept, a full scale prototype has been built and these tests have been accomplished on the prototype. By applying this integrated unit approach to the boiler concept development it has been possible to optimize the different building...

  13. Experimental determination of temperatures of the inner wall of a boiler combustion chamber for the purpose of verification of a CFD model

    Directory of Open Access Journals (Sweden)

    Petr Trávníček

    2011-01-01

    Full Text Available The paper focuses on the non-destructive method of determination of temperatures in the boiler combustion chamber. This method proves to be significant mainly as regards CFD (Computational Fluid Dynamics simulations of combustion processes, in case of which it is subsequently advisable to verify the data calculated using CFD software application with the actually measured data. Verification of the method was based on usage of reference combustion equipment (130 kW which performs combustion of a mixture of waste sawdust and shavings originating in the course of production of wooden furniture. Measuring of temperatures inside the combustion chamber is – considering mainly the high temperature values – highly demanding and requires a special type of temperature sensors. Furthermore, as regards standard operation, it is not possible to install such sensors without performing structural alterations of the boiler. Therefore, for the purpose of determination of these temperatures a special experimental device was constructed while exploiting a thermal imaging system used for monitoring of the surface temperature of outer wall of the reference boiler. Temperatures on the wall of the boiler combustion chamber were determined on the basis of data measured using the experimental device as well as data from the thermal imaging system. These values might serve for verification of the respective CFD model of combustion equipment.

  14. CFD modeling of small biomass-fired boilers, second stage; CFD-modellering av mindre biobraenslepannor, etapp 2

    Energy Technology Data Exchange (ETDEWEB)

    Loennermark, A. [Swedish National Testing and Research Inst., Boraas (Sweden); Leckner, B. [Chalmers Univ. of Techn., Goeteborg (Sweden). Dept. of Energy Technology

    2001-11-01

    The purpose of the project is to study how the design of the gas combustion chamber in a small boiler for biomass affects the emissions and how computer simulations can be used to decrease harmful emissions. The aim of the first part of the project was to investigate how phenomena and processes, important for the combustion, depend on various parameters. Within the frame of that part the temperature distribution, the flow pattern and the mixing processes have been studied. In the second part the combustion and the different reactions have been studied. A number of well-equipped combustion experiments in a small biomass-fired boiler have also been conducted to obtain better information about the boundary conditions. The results have been used to verify the simulations. The gas combustion chamber of a modern boiler using down draught firing has been simulated by using two Computational Fluid Dynamics codes, SOFIE and FLUENT. The results from the simulations show that with literature values for the reaction parameters, the reaction rates are controlled by mixing. This means that the reactions are fast and all the CO and the hydrocarbons were consumed. By varying the activation energy, it is possible to reach data that are more comparable with experimental data. The effects of the bowl in the gas combustion chamber on the combustion and mixing are discussed. The effects of the temperature and the radiation are also presented.

  15. Performance Analysis of a Reciprocating Piston Expander and a Plate Type Exhaust Gas Recirculation Boiler in a Water-Based Rankine Cycle for Heat Recovery from a Heavy Duty Diesel Engine

    Directory of Open Access Journals (Sweden)

    Gunnar Latz

    2016-06-01

    Full Text Available The exhaust gas in an internal combustion engine provides favorable conditions for a waste-heat recovery (WHR system. The highest potential is achieved by the Rankine cycle as a heat recovery technology. There are only few experimental studies that investigate full-scale systems using water-based working fluids and their effects on the performance and operation of a Rankine cycle heat recovery system. This paper discusses experimental results and practical challenges with a WHR system when utilizing heat from the exhaust gas recirculation system of a truck engine. The results showed that the boiler’s pinch point necessitated trade-offs between maintaining adequate boiling pressure while achieving acceptable cooling of the EGR and superheating of the water. The expander used in the system had a geometric compression ratio of 21 together with a steam outlet timing that caused high re-compression. Inlet pressures of up to 30 bar were therefore required for a stable expander power output. Such high pressures increased the pump power, and reduced the EGR cooling in the boiler because of pinch-point effects. Simulations indicated that reducing the expander’s compression ratio from 21 to 13 would allow 30% lower steam supply pressures without adversely affecting the expander’s power output.

  16. FY 2000 report on the survey project on potentiality of the environmental harmony coal utilization system. Potential study of the circulating fluidized bed boiler model project in Vietnam; 2000 nendo kankyo chowagata sekitan riyo system kanosei chosa jigyo hokokusho. Vietnam ni okeru junkan ryudosho boiler model jigyo jisshi kanosei chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    In Vietnam, survey was conducted of the project in which the adoption of circulating fluidized bed boiler (CFB) makes energy conservation and greenhouse effect gas reduction possible. CFB makes a marked decrease in SOx emission possible by using limestone as combustion bed material. As a result of the survey, the thermal power plant was not suitable for the model project due to its large size. However, it was found that two cement plants and one fiber plant having coal-fired boiler were suitable for survey. Nghi Son and Bim Son cement plants are typical cement plants in Vietnam. As a result of the hearing, they were eager to adopt CFB equipment. As to environmental improvement effects, in the thermal power plant with power source loads, emissions of SOx and NOx can be reduced by 79.0% and 72.5%, respectively. Further, in Nam Dinh Textile Company, emissions of SOx and NOx can be reduced by 79.8% and 84.6%, respectively, in case of converting boiler from the existing stoker boiler to CFB boiler. (NEDO)

  17. Characterizing and modeling the free recovery and constrained recovery behavior of a polyurethane shape memory polymer

    International Nuclear Information System (INIS)

    Volk, Brent L; Lagoudas, Dimitris C; Maitland, Duncan J

    2011-01-01

    In this work, tensile tests and one-dimensional constitutive modeling were performed on a high recovery force polyurethane shape memory polymer that is being considered for biomedical applications. The tensile tests investigated the free recovery (zero load) response as well as the constrained displacement recovery (stress recovery) response at extension values up to 25%, and two consecutive cycles were performed during each test. The material was observed to recover 100% of the applied deformation when heated at zero load in the second thermomechanical cycle, and a stress recovery of 1.5–4.2 MPa was observed for the constrained displacement recovery experiments. After the experiments were performed, the Chen and Lagoudas model was used to simulate and predict the experimental results. The material properties used in the constitutive model—namely the coefficients of thermal expansion, shear moduli, and frozen volume fraction—were calibrated from a single 10% extension free recovery experiment. The model was then used to predict the material response for the remaining free recovery and constrained displacement recovery experiments. The model predictions match well with the experimental data

  18. 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.

  19. 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)

    1999-12-31

    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.

  20. Hurricane Sandy, Disaster Preparedness, and the Recovery Model.

    Science.gov (United States)

    Pizzi, Michael A

    2015-01-01

    Hurricane Sandy was the second largest and costliest hurricane in U.S. history to affect multiple states and communities. This article describes the lived experiences of 24 occupational therapy students who lived through Hurricane Sandy using the Recovery Model to frame the research. Occupational therapy student narratives were collected and analyzed using qualitative methods and framed by the Recovery Model. Directed content and thematic analysis was performed using the 10 components of the Recovery Model. The 10 components of the Recovery Model were experienced by or had an impact on the occupational therapy students as they coped and recovered in the aftermath of the natural disaster. This study provides insight into the lived experiences and recovery perspectives of occupational therapy students who experienced Hurricane Sandy. Further research is indicated in applying the Recovery Model to people who survive disasters. Copyright © 2015 by the American Occupational Therapy Association, Inc.

  1. Hydro models and salmon recovery in the northwest

    International Nuclear Information System (INIS)

    Dragoon, K.

    1993-01-01

    Hydro regulation models provide extensive support for analyzing the efficacy of salmon recovery plans in the Northwest. Power planners developed these computer programs to help plan and efficiently operate a large multiple use river system. The models represent physical relationships and operational requirements on the system. They also simulate coordinated system operations for efficient power generation. These models are being pressed into service to provide data for fish recovery plans. They provide important information about hydro system capabilities and responses to recovery programs. However, the models cannot meet all of the analytical needs of fish biologists working toward salmon recovery

  2. Visualisation of the velocity field in a scaled water model for validation of numerical calculations for a powder fuelled boiler

    Energy Technology Data Exchange (ETDEWEB)

    Dumortier, Laurent [Luleaa Univ. of Technology (Sweden)

    2001-01-01

    Validation of numerical predictions of the flow field in a powder fired industry boiler by flow visualisation in a water model has been studied. The bark powder fired boiler at AssiDomaen Kraftliner in Piteaa has been used as a case study. A literature study covering modelling of combusting flows by water models and different flow visualisation techniques has been carried out. The main conclusion as regards the use of water models is that only qualitative information can be expected. As far as turbulent flow is assured in the model as well as the real furnace, the same Reynolds number is not required. Geometrical similarity is important but modelling of burner jets requires adaptation of the jet diameters in the model. Guidelines for this are available and are presented in the report. The review of visualisation techniques shows that a number of methods have been used successfully for validation of flow field predictions. The conclusion is that the Particle Image Velocimetry and Particle Tracking Velocimetry methods could be very suitable for validation purposes provided that optical access is possible. The numerical predictions include flow fields in a 1130 scale model of the AssiDomaen furnace with water flow as well as flow and temperature fields in the actual furnace. Two burner arrangements were considered both for the model and the actual furnace, namely the present configuration with four front burners and a proposed modification where an additional burner is positioned at a side wall below the other burners. There are many similarities between the predicted flow fields in the model and the full scale furnace but there are also some differences, in particular in the region above the burners and the effects of the low region re-circulation on the lower burner jets. The experiments with the water model have only included the arrangement with four front burners. There were problems determining the velocities in the jets and the comparisons with predictions are

  3. Boiler water regime

    Science.gov (United States)

    Khavanov, Pavel; Chulenyov, Anatoly

    2017-10-01

    Active development of autonomous heating the past 25 years has led to the widespread use of hot-water boilers of small capacity up to 2.5 MW. Rational use of the design of autonomous sources of heating boilers design features significantly improve their technical, economic and operational performance. This publication reviewed and analyzed a number of features of the design, operation and exploitation of boilers of small capacity, significantly affecting the efficiency and reliability of their application.

  4. Boiler conversions for biomass

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-31

    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.

  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. New thinking for the boiler room.

    Science.gov (United States)

    Rose, Wayne

    2008-09-01

    Wayne Rose, marketing manager at integrated plant room manufacturer Armstrong Integrated Systems, explains how increasing use of off-site manufacture, the latest 3D modelling technology, and advances in control technology, are revolutionising boiler room design and construction.

  7. Silva. EDF two-phase 1D annular model of a CFB boiler furnace

    Energy Technology Data Exchange (ETDEWEB)

    Montat, D.; Fauquet, Ph. [Electricite de France (EDF), 78 - Chatou (France). Researckh and Development Div.; Lafanechere, L.; Bursi, J.M. [Electricite de France (EDF) (France). Construction Div.

    1997-01-01

    SILVA computer code is used for the modelling of the thermal-hydraulics and of the combustion of a coal-fired CFBC solid loop. In a first step, only the furnace is considered. The model is based on a 1D annular two phases description of the hydrodynamics. The model is based on particle mass balances and pressure drop calculations. A basic combustion model is incorporated into this model. The coal combustion is divided in two phases, the combustion of volatile matter and the heterogeneous combustion. The model has been developed within LEGO software and can be included into the global model of the solid loop developed by EDF. (author) 26 refs.

  8. Job demands-resources model in the context of recovery : Testing recovery experiences as mediators

    OpenAIRE

    Kinnunen, Ulla; Feldt, Taru; Siltaloppi, Marjo; Sonnentag, Sabine

    2011-01-01

    The aim of the present study was to extend the original Job Demands– Resources (JD-R) model by taking into account recovery as an important mediation mechanism between work characteristics and well-being/ill-health. Specifically, we examined whether recovery experiences—strategies promoting recovery—might have a mediating role in the JD-R model among 527 employees from a variety of different jobs. The results showed that psychological detachment fully mediated the effects of job demands on fa...

  9. Energy recovery and emissions of PBDD/Fs and PBDEs from cocombustion of woodchip and wastewater sludge in an industrial boiler.

    Science.gov (United States)

    Chang, Shun-Shiang Chang; Lee, Wen-Jhy Lee; Wang, Lin-Chi Wang; Chang-Chien, Guo-Ping Chang-Chien; Wu, Chang-Yu

    2013-01-01

    The emissions of polybrominated dibenzo-pdioxins,dibenzofurans (PBDD/Fs), and polybrominated diphenyl ethers (PBDEs) from trial combustion of 10 wt % dried industrial wastewater-treatment sludge (IWTS) and 90 wt % woodchip in an industrial boiler were investigated and compared to that from woodchip combustion. The PBDD/F toxic equivalent (TEQ) andPBDE emissions increased from 0.121 pg TEQ Nm−3 and 2260 pgNm−3, respectively, of the woodchip combustion to 0.211 pg TEQNm−3 and 4200 pg Nm−3, respectively, of the trial combustion.PBDD/F and PBDE congener profiles of inputs and outputs of the same type of combustion were similar; they also show similarity between woodchip and trial combustions, revealing that the destruction pathway was little affected by the introduction of the IWTS. The fates of PBDD/Fs and PBDEs show that the indigenous pollutants in the feed were effectively depleted (>93.5%). The dominant releasing route of PBDD/F and PBDE shifted from the stack flue gas of woodchip combustion to the ashes of trial combustion. This study demonstrates that co-combustion not only handles the fast growing sludge stream but also yields a saving of 26.3% in the fuel cost and treatment fees of sludge and ashes.

  10. Electric utility CFB boilers

    International Nuclear Information System (INIS)

    Fairbanks, D.A.

    1991-01-01

    This paper reports on Circulating Fluidized Bed (CFB) boiler technology which caught the attention of boiler users: first for its technical advantages of reduced air emissions and low grade fuel tolerance, then later for its problems in becoming a reliable process. Refractory longevity and fuel feed reliability plagued a number of new installations. The efficacy of CFB technology is now more assured with the recent success of Texas-New Mexico Power Company's 160 MWe CFB based units, the world's largest operating CFB boilers. Most of the more notable CFB development problems have been successfully addressed by these units. The TNP units have demonstrated that CFB's can reliable produce high capacity factors at low emission rates using a fuel that has traditionally hampered the operation of pulverized coal (PC) boilers and without the attendant problems associated with sulfur scrubbers required by PC boilers

  11. Modeling and Simulation of Energy Recovery from a Photovoltaic ...

    African Journals Online (AJOL)

    Modeling and Simulation of Energy Recovery from a Photovoltaic Solar cell. ... Photovoltaic (PV) solar cell which converts solar energy directly into electrical energy is one of ... model of the solar panel which could represent the real systems.

  12. Modeling and optimization of integrated exhaust gas recirculation and multi-stage waste heat recovery in marine engines

    DEFF Research Database (Denmark)

    Kyriakidis, Fotis; Sørensen, Kim; Singh, Shobhana

    2017-01-01

    Waste heat recovery combined with exhaust gas recirculation is a promising technology that can address both the issue of NOx (nitrogen oxides) reduction and fuel savings by including a pressurized boiler. In the present study, a theoretical optimization of the performance of two different...... configurations of steam Rankine cycles, with integrated exhaust gas recirculation for a marine diesel engine, is presented. The first configuration employs two pressure levels and the second is configured with three-pressure levels. The models are developed in MATLAB based on the typical data of a large two......-stroke marine diesel engine. A turbocharger model together with a blower, a pre-scrubber and a cooler for the exhaust gas recirculation line, are included. The steam turbine, depending on the configuration, is modeled as either a dual or triple pressure level turbine. The condensation and pre-heating process...

  13. Towards a CFD-based mechanistic deposit formation model for straw-fired boilers

    DEFF Research Database (Denmark)

    Kær, Søren Knudsen; Rosendahl, Lasse Aistrup; Baxter, L.L.

    2006-01-01

    is configured entirely through a graphical user interface integrated in the standard FLUENTe interface. The model considers fine and coarse mode ash deposition and sticking mechanisms for the complete deposit growth, as well as an influence on the local boundary conditions for heat transfer due to thermal...... in the reminder of the paper. The growth of deposits on furnace walls and super heater tubes is treated including the impact on heat transfer rates determined by the CFD code. Based on the commercial CFD code FLUENTe, the overall model is fully implemented through the User Defined Functions. The model...

  14. Neural Network Based Model of an Industrial Oil-Fired Boiler System ...

    African Journals Online (AJOL)

    A two-layer feed-forward neural network with Hyperbolic tangent sigmoid ... The neural network model when subjected to test, using the validation input data; ... Proportional Integral Derivative (PID) Controller is used to control the neural ...

  15. Salmon recovery planning using the VELMA model

    Science.gov (United States)

    We developed a set of tools to provide decision support for community-based salmon recovery planning in Pacific Northwest watersheds. This seminar describes how these tools are being integrated and applied in collaboration with Puget Sound tribes and community stakeholders to add...

  16. IAPCS: A COMPUTER MODEL THAT EVALUATES POLLUTION CONTROL SYSTEMS FOR UTILITY BOILERS

    Science.gov (United States)

    The IAPCS model, developed by U.S. EPA`s Air and Energy Engineering Research Laboratory and made available to the public through the National Technical Information Service, can be used by utility companies, architectural and engineering companies, and regulatory agencies at all l...

  17. Modeling of the Temperature Field Recovery in the Oil Pool

    Science.gov (United States)

    Khabibullin, I. L.; Davtetbaev, A. Ya.; Mar'in, D. F.; Khisamov, A. A.

    2018-05-01

    This paper considers the problem on mathematical modeling of the temperature field recovery in the oil pool upon termination of injection of water into the pool. The problem is broken down into two stages: injection of water and temperature and pressure recovery upon termination of injection. A review of the existing mathematical models is presented, analytical solutions for a number of cases have been constructed, and a comparison of the analytical solutions of different models has been made. In the general form, the expression has been obtained that permits determining the temperature change in the oil pool upon termination of injection of water (recovery of the temperature field).

  18. A model for recovery kinetics of aluminum after large strain

    DEFF Research Database (Denmark)

    Yu, Tianbo; Hansen, Niels

    2012-01-01

    A model is suggested to analyze recovery kinetics of heavily deformed aluminum. The model is based on the hardness of isothermal annealed samples before recrystallization takes place, and it can be extrapolated to longer annealing times to factor out the recrystallization component of the hardness...... for conditions where recovery and recrystallization overlap. The model is applied to the isothermal recovery at temperatures between 140 and 220°C of commercial purity aluminum deformed to true strain 5.5. EBSD measurements have been carried out to detect the onset of discontinuous recrystallization. Furthermore...

  19. CECIL lances Bruce's boilers

    International Nuclear Information System (INIS)

    Malaugh, J.; Monaghan, D.

    1994-01-01

    Over the past few years Ontario Hydro has become increasingly concerned about accumulations of sludge in its nuclear plant boilers, so a comprehensive sludge management programme has been instituted to combat build-up. This included developing the tele-operated robot CECIL (Consolidated Edison Combined Inspection and Lancing) equipment, originally designed for work in PWRs, for CANDU boilers. This required a significantly reconfigured robotic system as well as modifications to the boilers themselves. Work on the Bruce A reactor is described. (4 figures). (author)

  20. Charting the boiler market

    International Nuclear Information System (INIS)

    2003-01-01

    The ''boiler market'' of electricity, sometimes called unsecured transmission, is electric power consumption that in public statistics is restricted by the obligation of the customers to cut their consumption at short notice and therefore are granted some discount on the network lease. The present document is part of a project that aims to provide a better understanding of the flexibility in the Norwegian power market, limited by the power-intensive industry and the boiler market. It discusses the boiler market. It begins with a discusses of the available statistics, where different sources show very dissimilar consumption figures. Then it examines how the consumption in the boiler market developed during the winter 2002/2003. Finally, there is a description of the regulations of unsecured transmission and how the various network owners adapt to the regulations.

  1. Dynamic Boiler Performance

    DEFF Research Database (Denmark)

    Sørensen, Kim

    Traditionally, boilers have been designed mainly focussing on the static operation of the plant. The dynamic capability has been given lower priority and the analysis has typically been limited to assuring that the plant was not over-stressed due to large temperature gradients. New possibilities...... developed. Analyzing boilers for dynamic operation gives rise to a number of opposing aims: shrinking and swelling, steam quality, stress levels, control system/philosophy, pressurization etc. Common for these opposing aims is that an optimum can be found for selected operation conditions. The framework has...... for buying and selling energy has increased the focus on the dynamic operation capability, efciency, emissions etc. For optimizing the design of boilers for dynamic operation a quantication of the dynamic capability is needed. A framework for optimizing design of boilers for dynamic operation has been...

  2. Theoretical modeling for optimizing horizontal production well placement in thermal recovery environments to maximize recovery

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeois, D.J. [Schlumberger Canada Ltd., Calgary, AB (Canada)

    2008-07-01

    Heavy oil has a high viscosity and a low API gravity rating. Since it is difficult to get a fluid of this nature to flow, enhanced oil recovery techniques are required to extract the oil from the reservoir. Thermal recovery strategies such as steam assisted gravity drainage (SAGD) and cyclic steam injection stimulation (CSS) can be used. These techniques involve injecting steam into a formation which heats up the fluid in place decreasing its viscosity and allowing it to flow into the producing well bore. In order to maximize hydrocarbon recovery from this type of geological environment, the placement of the horizontal production well bore relative to the base of the reservoir is important. In conventional oil and gas plays, well placement methods involving directional deep resistivity logging while drilling (DDR-LWD) measurements to map formation contacts while drilling have enabled wells to be placed relative to formation boundaries. This paper discussed a study that presented some theoretical resistivity inversion and forward modeling results generated from a three-dimensional geocellular model to confirm that this evolving DDR-LWD technology may be applicable to western Canada's Athabasca heavy oil drilling environments. The paper discussed the effect of well bore position, thermal recovery, and pro-active well placement. Resistivity modeling work flow was also presented. It was concluded that being able to drill a horizontal production well relative to the base of the formation could help minimize abandoned oil ultimately leading to better recovery. 4 refs., 8 figs.

  3. Hydropower recovery in water supply systems: Models and case study

    International Nuclear Information System (INIS)

    Vilanova, Mateus Ricardo Nogueira; Balestieri, José Antônio Perrella

    2014-01-01

    Highlights: • We present hydropower recovery models for water supply systems. • Hydropower recovery potential in water supply systems is highly variable. • The case studied could make the supply systems self-sufficient in terms of energy. • Hydropower recovery can reduce GHGs emissions and generate carbon credits. - Abstract: The energy efficiency of water supply systems can be increased through the recovery of hydraulic energy implicit to the volumes of water transported in various stages of the supply process, which can be converted into electricity through hydroelectric recovery systems. Such a process allows the use of a clean energy source that is usually neglected in water supplies, reducing its dependence on energy from the local network and the system’s operation costs. This article evaluates the possibilities and benefits of the use of water supply facilities, structures and equipment for hydraulic energy recovery, addressing several applicable hydroelectric models. A real case study was developed in Brazil to illustrate the technical, economic and environmental aspects of hydropower recovery in water supply systems

  4. 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....

  5. Control Properties of Bottom Fired Marine Boilers

    DEFF Research Database (Denmark)

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

    2005-01-01

    This paper focuses on model analysis of a dynamic model of a bottom fired one-pass smoke tube boiler. Linearised versions of the model are analysed to determine how gain, time constants and right half plane zeros (caused by the shrink-and-swell phenomenon) depend on the steam flow load. Furthermore...... the interactions in the system are inspected to analyse potential benefit from using a multivariable control strategy in favour of the current strategy based on single loop theory. An analysis of the nonlinear model is carried out to further determine the nonlinear characteristics of the boiler system...

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

    Energy Technology Data Exchange (ETDEWEB)

    None

    2006-06-01

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

  7. 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 analys...

  8. Condensing boiler applications in the process industry

    International Nuclear Information System (INIS)

    Chen, Qun; Finney, Karen; Li, Hanning; Zhang, Xiaohui; Zhou, Jue; Sharifi, Vida; Swithenbank, Jim

    2012-01-01

    Major challenging issues such as climate change, energy prices and fuel security have focussed the attention of process industries on their energy efficiency and opportunities for improvement. The main objective of this research study was to investigate technologies needed to exploit the large amount of low grade heat available from a flue gas condensing system through industrial condensing boilers. The technology and application of industrial condensing boilers in various heating systems were extensively reviewed. As the condensers require site-specific engineering design, a case study was carried out to investigate the feasibility (technically and economically) of applying condensing boilers in a large scale district heating system (40 MW). The study showed that by recovering the latent heat of water vapour in the flue gas through condensing boilers, the whole heating system could achieve significantly higher efficiency levels than conventional boilers. In addition to waste heat recovery, condensing boilers can also be optimised for emission abatement, especially for particle removal. Two technical barriers for the condensing boiler application are corrosion and return water temperatures. Highly corrosion-resistant material is required for condensing boiler manufacture. The thermal design of a 'case study' single pass shell-and-tube condensing heat exchanger/condenser showed that a considerable amount of thermal resistance was on the shell-side. Based on the case study calculations, approximately 4900 m 2 of total heat transfer area was required, if stainless steel was used as a construction material. If the heat transfer area was made of carbon steel, then polypropylene could be used as the corrosion-resistant coating material outside the tubes. The addition of polypropylene coating increased the tube wall thermal resistance, hence the required heat transfer area was approximately 5800 m 2 . Net Present Value (NPV) calculations showed that the choice of a carbon

  9. A theoretical approach for energy saving in industrial steam boilers

    International Nuclear Information System (INIS)

    Sabry, T.I.; Mohamed, N.H.; Elghonimy, A.M.

    1993-01-01

    Optimization of the performance characteristics of such a steam boiler has been analyzed theoretically. Suitable thermodynamic relations have been utilized here to construct a computer model that would carry out the boiler performance characteristics at different operating parameters (e.g.; amount of excess air, fuel type, rate of blowdown preheating of combustion air and flow gases temperature). The results demonstrate that this computer model is to be used successfully in selecting the different operating parameters of the steam boiler at variant loads considering the best economical operation. Besides, this model can be used to investigate the sensitivity of the performance characteristics to the deviation of the boiler operating parameters from their optimum values. It was found also that changing the operating parameters beside the type of fuel in a boiler affects its performance characteristics. 3 figs

  10. Computational neurorehabilitation: modeling plasticity and learning to predict recovery.

    Science.gov (United States)

    Reinkensmeyer, David J; Burdet, Etienne; Casadio, Maura; Krakauer, John W; Kwakkel, Gert; Lang, Catherine E; Swinnen, Stephan P; Ward, Nick S; Schweighofer, Nicolas

    2016-04-30

    Despite progress in using computational approaches to inform medicine and neuroscience in the last 30 years, there have been few attempts to model the mechanisms underlying sensorimotor rehabilitation. We argue that a fundamental understanding of neurologic recovery, and as a result accurate predictions at the individual level, will be facilitated by developing computational models of the salient neural processes, including plasticity and learning systems of the brain, and integrating them into a context specific to rehabilitation. Here, we therefore discuss Computational Neurorehabilitation, a newly emerging field aimed at modeling plasticity and motor learning to understand and improve movement recovery of individuals with neurologic impairment. We first explain how the emergence of robotics and wearable sensors for rehabilitation is providing data that make development and testing of such models increasingly feasible. We then review key aspects of plasticity and motor learning that such models will incorporate. We proceed by discussing how computational neurorehabilitation models relate to the current benchmark in rehabilitation modeling - regression-based, prognostic modeling. We then critically discuss the first computational neurorehabilitation models, which have primarily focused on modeling rehabilitation of the upper extremity after stroke, and show how even simple models have produced novel ideas for future investigation. Finally, we conclude with key directions for future research, anticipating that soon we will see the emergence of mechanistic models of motor recovery that are informed by clinical imaging results and driven by the actual movement content of rehabilitation therapy as well as wearable sensor-based records of daily activity.

  11. Ethnicity and cultural models of recovery from breast cancer.

    Science.gov (United States)

    Coreil, Jeannine; Corvin, Jaime A; Nupp, Rebecca; Dyer, Karen; Noble, Charlotte

    2012-01-01

    Recovery narratives describe the culturally shared understandings about the ideal or desirable way to recover from an illness experience. This paper examines ethnic differences in recovery narratives among women participating in breast cancer support groups in Central Florida, USA. It compares groups serving African-American, Latina, and European American women, with the objective of better understanding the appeal of ethnic-specific illness support groups for culturally diverse populations. A mixed-method study design combined qualitative and quantitative measures, including in-depth interviews, participant observation at support group meetings, collection of printed documents, and a structured survey. Core elements of the recovery narrative drew from the dominant societal cancer discourse of optimism and personal transformation through adversity; however, important ethnic differences were evident in the meaning assigned to these themes. Groups gave distinctive salience to themes of faith and spirituality, empowerment through the migration experience, and becoming a better person through the journey of recovery. The findings suggest that ethnic cancer support groups draw upon dominant societal discourses about cancer, but they espouse distinctive recovery narratives that are consonant with the groups' cultural models of illness. Similarity between ethnic members' individual recovery narratives and that of the group may contribute to the appeal of ethnic illness support groups for culturally diverse populations.

  12. Thermomechanical finite element analysis of hot water boiler structure

    Directory of Open Access Journals (Sweden)

    Živković Dragoljub S.

    2012-01-01

    Full Text Available The paper presents an application of the Finite Elements Method for stress and strain analysis of the hot water boiler structure. The aim of the research was to investigate the influence of the boiler scale on the thermal stresses and strains of the structure of hot water boilers. Results show that maximum thermal stresses appear in the zone of the pipe carrying wall of the first reversing chamber. This indicates that the most critical part of the boiler are weld spots of the smoke pipes and pipe carrying plate, which in the case of significant scale deposits can lead to cracks in the welds and water leakage from the boiler. The nonlinear effects were taken into account by defining the bilinear isotropic hardening model for all boiler elements. Temperature dependency was defined for all relevant material properties, i. e. isotropic coefficient of thermal expansion, Young’s modulus, and isotropic thermal conductivity. The verification of the FEA model was performed by comparing the measured deformations of the hot water boiler with the simulation results. As a reference object, a Viessmann - Vitomax 200 HW boiler was used, with the installed power of 18.2 MW. CAD modeling was done within the Autodesk Inventor, and stress and strain analysis was performed in the ANSYS Software.

  13. Wood fuelled boiler operating costs

    International Nuclear Information System (INIS)

    Sandars, D.L.

    1995-01-01

    This report is a management study into the operating costs of wood-fired boilers. Data obtained from existing wood-fired plant has been analysed and interpreted using the principles of machinery management and the science that underlies the key differences between this fuel and any other. A set of budgeting principles has been developed for the key areas of labour requirement, insurance, maintenance and repair and electricity consumption. Other lesser cost centres such as the provision of shelter and the effects of neglect and accidents have also been considered, and a model constructed. (author)

  14. A dual model approach to ground water recovery trench design

    International Nuclear Information System (INIS)

    Clodfelter, C.L.; Crouch, M.S.

    1992-01-01

    The design of trenches for contaminated ground water recovery must consider several variables. This paper presents a dual-model approach for effectively recovering contaminated ground water migrating toward a trench by advection. The approach involves an analytical model to determine the vertical influence of the trench and a numerical flow model to determine the capture zone within the trench and the surrounding aquifer. The analytical model is utilized by varying trench dimensions and head values to design a trench which meets the remediation criteria. The numerical flow model is utilized to select the type of backfill and location of sumps within the trench. The dual-model approach can be used to design a recovery trench which effectively captures advective migration of contaminants in the vertical and horizontal planes

  15. Optimising boiler performance.

    Science.gov (United States)

    Mayoh, Paul

    2009-01-01

    Soaring fuel costs continue to put the squeeze on already tight health service budgets. Yet it is estimated that combining established good practice with improved technologies could save between 10% and 30% of fuel costs for boilers. Paul Mayoh, UK technical manager at Spirax Sarco, examines some of the practical measures that healthcare organisations can take to gain their share of these potential savings.

  16. 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…

  17. Least Square Fast Learning Network for modeling the combustion efficiency of a 300WM coal-fired boiler.

    Science.gov (United States)

    Li, Guoqiang; Niu, Peifeng; Wang, Huaibao; Liu, Yongchao

    2014-03-01

    This paper presents a novel artificial neural network with a very fast learning speed, all of whose weights and biases are determined by the twice Least Square method, so it is called Least Square Fast Learning Network (LSFLN). In addition, there is another difference from conventional neural networks, which is that the output neurons of LSFLN not only receive the information from the hidden layer neurons, but also receive the external information itself directly from the input neurons. In order to test the validity of LSFLN, it is applied to 6 classical regression applications, and also employed to build the functional relation between the combustion efficiency and operating parameters of a 300WM coal-fired boiler. Experimental results show that, compared with other methods, LSFLN with very less hidden neurons could achieve much better regression precision and generalization ability at a much faster learning speed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Foam for Enhanced Oil Recovery : Modeling and Analytical Solutions

    NARCIS (Netherlands)

    Ashoori, E.

    2012-01-01

    Foam increases sweep in miscible- and immiscible-gas enhanced oil recovery by decreasing the mobility of gas enormously. This thesis is concerned with the simulations and analytical solutions for foam flow for the purpose of modeling foam EOR in a reservoir. For the ultimate goal of upscaling our

  19. Thermodynamic performance analysis and algorithm model of multi-pressure heat recovery steam generators (HRSG) based on heat exchangers layout

    International Nuclear Information System (INIS)

    Feng, Hongcui; Zhong, Wei; Wu, Yanling; Tong, Shuiguang

    2014-01-01

    Highlights: • A general model of multi-pressure HRSG based on heat exchangers layout is built. • The minimum temperature difference is introduced to replace pinch point analysis. • Effects of layout on dual pressure HRSG thermodynamic performances are analyzed. - Abstract: Changes of heat exchangers layout in heat recovery steam generator (HRSG) will modify the amount of waste heat recovered from flue gas; this brings forward a desire for the optimization of the design of HRSG. In this paper the model of multi-pressure HRSG is built, and an instance of a dual pressure HRSG under three different layouts of Taihu Boiler Co., Ltd. is discussed, with specified values of inlet temperature, mass flow rate, composition of flue gas and water/steam parameters as temperature, pressure etc., steam mass flow rate and heat efficiency of different heat exchangers layout of HRSG are analyzed. This analysis is based on the laws of thermodynamics and incorporated into the energy balance equations for the heat exchangers. In the conclusion, the results of the steam mass flow rate, heat efficiency obtained for three heat exchangers layout of HRSGs are compared. The results show that the optimization of heat exchangers layout of HRSGs has a great significance for waste heat recovery and energy conservation

  20. Multi-objective Optimization of Coal-fired Boiler Combustion Based on NSGA-II

    OpenAIRE

    Tingfang Yu; Hongzhen Zhu; Chunhua Peng

    2013-01-01

    NOx emission characteristics and overall heat loss model for a 300MW coal-fired boiler were established by Back Propagation (BP) neural network, by which the the functional relationship between outputs (NOx emissions & overall heat loss of the boiler) and inputs (operational parameters of the boiler) of a coal-fired boiler can be predicted. A number of field test data from a full-scale operating 300MWe boiler were used to train and verify the BP model. The NOx emissions & heat loss pr...

  1. Establishing endangered species recovery criteria using predictive simulation modeling

    Science.gov (United States)

    McGowan, Conor P.; Catlin, Daniel H.; Shaffer, Terry L.; Gratto-Trevor, Cheri L.; Aron, Carol

    2014-01-01

    Listing a species under the Endangered Species Act (ESA) and developing a recovery plan requires U.S. Fish and Wildlife Service to establish specific and measurable criteria for delisting. Generally, species are listed because they face (or are perceived to face) elevated risk of extinction due to issues such as habitat loss, invasive species, or other factors. Recovery plans identify recovery criteria that reduce extinction risk to an acceptable level. It logically follows that the recovery criteria, the defined conditions for removing a species from ESA protections, need to be closely related to extinction risk. Extinction probability is a population parameter estimated with a model that uses current demographic information to project the population into the future over a number of replicates, calculating the proportion of replicated populations that go extinct. We simulated extinction probabilities of piping plovers in the Great Plains and estimated the relationship between extinction probability and various demographic parameters. We tested the fit of regression models linking initial abundance, productivity, or population growth rate to extinction risk, and then, using the regression parameter estimates, determined the conditions required to reduce extinction probability to some pre-defined acceptable threshold. Binomial regression models with mean population growth rate and the natural log of initial abundance were the best predictors of extinction probability 50 years into the future. For example, based on our regression models, an initial abundance of approximately 2400 females with an expected mean population growth rate of 1.0 will limit extinction risk for piping plovers in the Great Plains to less than 0.048. Our method provides a straightforward way of developing specific and measurable recovery criteria linked directly to the core issue of extinction risk. Published by Elsevier Ltd.

  2. Thermo-kinetic modeling and optimization of the sulfur recovery unit thermal stage

    International Nuclear Information System (INIS)

    Zarei, Samane; Ganji, Hamid; Sadi, Maryam; Rashidzadeh, Mehdi

    2016-01-01

    Highlights: • The Claus reaction furnace was modeled using the corrected Gibbs energy minimization. • Using the corrected model, a significant error reduction from 33.50 to 7.86% occurred. • The waste heat boiler was modeled using plant data and a new H_2S decomposition rate. • The combined model could reasonably predict the experimental data with 6.50% error. • An optimization was carried out to control the operating variables of an existing plant. - Abstract: In this study, the reaction furnace of Claus process was modeled using the Gibbs free energy minimization method, which involved new parameters in correlations of thermodynamic properties. Using the new parameters, a significant error reduction from 33.50% to 7.86% occurred in the prediction of molar flow rate of components. Subsequently, the waste heat boiler attached to the reaction furnace was modeled using experimental plant data and a new hydrogen sulfide decomposition rate. Utilizing this new rate expression, the capability of the model in H_2 molar flow rate prediction was enhanced, and the mean absolute percentage error of the model for H_2 and H_2S species reached 12.94% and 9.43%, respectively. The combined model including corrected equilibrium model for the reaction furnace and corrected kinetic model for the waste heat boiler could reasonably predict the experimental data so that the mean absolute percentage error reached to 6.50%. An optimization study was carried out to examine the operating condition of the Claus reaction furnace and the waste heat boiler in order to maximize sulfur production and minimize COS emission while maintaining H_2S to SO_2 flow ratio at constant value of 2.

  3. Fouling control in biomass boilers

    Energy Technology Data Exchange (ETDEWEB)

    Romeo, Luis M.; Gareta, Raquel [Centro de Investigacion de Recursos y Consumos Energeticos (CIRCE), Universidad de Zaragoza, Centro Politecnico Superior, Maria de Luna, 3, 50018 Zaragoza (Spain)

    2009-05-15

    One of the important challenges for biomass combustion in industrial applications is the fouling tendency and how it affects to the boiler performance. The classical approach for this question is to activate sootblowing cycles with different strategies to clean the boiler (one per shift, one each six hours..). Nevertheless, it has been often reported no effect on boiler fouling or an excessive steam consumption for sootblowing. This paper illustrates the methodology and the application to select the adequate time for activating sootblowing in an industrial biomass boiler. The outcome is a control strategy developed with artificial intelligence (Neural Network and Fuzzy Logic Expert System) for optimizing the biomass boiler cleaning and maximizing heat transfer along the time. Results from an optimize sootblowing schedule show savings up to 12 GWh/year in the case-study biomass boiler. Extra steam generation produces an average increase of turbine power output of 3.5%. (author)

  4. Establishing an energy efficiency recommendation for commercial boilers

    International Nuclear Information System (INIS)

    Ware, Michelle J.

    2000-01-01

    To assist the federal government in meeting its energy reduction goals, President Clinton's Executive Order 12902 established the Procurement Challenge, which directed all federal agencies to purchase equipment within the top 25th percentile of efficiency. Under the direction of DOE's Federal Energy Management Program (FEMP), the Procurement Challenge's goal is to create efficiency recommendations for all energy-using products that could substantially impact the government's energy reduction goals, like commercial boilers. A typical 5,000,000 Btuh boiler, with a thermal efficiency of 83.2%, can have lifetime energy cost savings of$40,000 when compared to a boiler with a thermal efficiency of 78%. For the federal market, which makes up 2% of the boiler market, this means lifetime energy cost savings of over$25,600,000. To establish efficiency recommendations, FEMP uses standardized performance ratings for products sold in the marketplace. Currently, the boiler industry uses combustion efficiency and, sometimes, thermal efficiency performance measures when specifying a commercial boiler. For many years, the industry has used these efficiency measures interchangeably, causing confusion about boiler performance measurements, and making it difficult for FEMP to establish the top 25th percentile of efficiency. This paper will illustrate the method used to establish FEMP's recommendation for boilers. The method involved defining a correlation between thermal and combustion efficiency among boiler classifications; using the correlation to model a data set of all the boiler types available in the market; and identifying how the correlation affected the top 25th percentile analysis. The paper also will discuss the applicability of this method for evaluating other equipment for which there are limited data on performance ratings

  5. Mod increases AGR boiler output

    International Nuclear Information System (INIS)

    Jones, W.K.C.; Rider, G.; Taylor, D.E.

    1986-01-01

    During the commissioning runs of the first reactor units at Heysham I and Hartlepool Advanced Gas-cooled Reactors (AGRs), non-uniform temperature distributions were observed across individual boiler units which were more severe than those predicted from the design analysis. This article describes the re-orificing (referruling) of the boilers to overcome this problem. The referruling has reduced boiler sensitivity and resulted in an increase of load of 7 or 8%. (U.K.)

  6. A model for improving endangered species recovery programs

    Science.gov (United States)

    Miller, Brian; Reading, Richard; Conway, Courtney; Jackson, Jerome A.; Hutchins, Michael; Snyder, Noel; Forrest, Steve; Frazier, Jack; Derrickson, Scott

    1994-09-01

    This paper discusses common organizational problems that cause inadequate planning and implementation processes of endangered species recovery across biologically dissimilar species. If these problems occur, even proven biological conservation techniques are jeopardized. We propose a solution that requires accountability in all phases of the restoration process and is based on cooperative input among government agencies, nongovernmental conservation organizations, and the academic community. The first step is formation of a task-oriented recovery team that integrates the best expertise into the planning process. This interdisciplinary team should be composed of people whose skills directly address issues critical for recovery. Once goals and procedures are established, the responsible agency (for example, in the United States, the US Fish and Wildlife Service) could divest some or all of its obligation for implementing the plan, yet still maintain oversight by holding implementing entities contractually accountable. Regular, periodic outside review and public documentation of the recovery team, lead agency, and the accomplishments of implementing bodies would permit evaluation necessary to improve performance. Increased cooperation among agency and nongovernmental organizations provided by this model promises a more efficient use of limited resources toward the conservation of biodiversity.

  7. Numerical simulation of a biomass fired grate boiler

    DEFF Research Database (Denmark)

    Yin, Chungen; Rosendahl, Lasse; Kær, Søren Knudsen

    2006-01-01

    Computational fluid dynamic (CFD) analysis of the thermal flow in the combustion furnace of a biomass-fired grate boiler provides crucial insight into the boiler's performance. Quite a few factors play important roles in a general CFD analysis, such as grid, models, discretization scheme and so on....... For a grate boiler, the modeling the interaction of the fuel bed and the gas phase above the bed is also essential. Much effort can be found in literature on developing bed models whose results are introduced into CFD simulations of freeboard as inlet conditions. This paper presents a CFD analysis...... of the largest biomass-fired grate boiler in Denmark. The focus of this paper is to study how significantly an accurate bed model can affect overall CFD results, i.e., how necessarily it is to develop an accurate bed model in terms of the reliability of CFD results. The ultimate purpose of the study is to obtain...

  8. [The Global Model of Public Mental Health and Recovery Mentors].

    Science.gov (United States)

    Pelletier, Jean-François; Auclair, Émilie

    Objectives The aim of this paper is to revisit the Global Model of Public Mental Health (GMPMH) in light of the 4th Civic Forum. Recovery mentors of the University of Recovery chaired this public event, which was held in East-end Montreal, Canada, in 2016. The University of Recovery is a concept of co-learning among its members.Methods Being able to refer to international conventions and human rights standards is a key component of a genuine global approach that is supportive of individuals and communities in their quest for recovery and full citizenship. The GMPMH was inspired by the ecological approach in public health and health promotion programs, while adding to that approach the recovery mentors, as agents of mental health policies and legislation transformation. The GMPMH integrates recovery- and citizenship-oriented practices through the Ottawa Charter for Health Promotion of the World Health Organization. Indeed, here the GMPMH is said to be global in that the supranational and individual levels reinforce each other, taking turns with a) a set of legal rules and international conventions on human rights, including those of disabled persons, and b) the active involvement and agency of recovery mentors who can evoke these rules and conventions as part of a plea for the recognition of their personal and collective capacity for change; they acted as tracers of recovery trajectories during the Civic Forum. The GMPMH was first published in 2009, and revisited in 2013. While this latter revision was based on the 3rd Civic Forum, in this paper we use the same approach to revisit the GMPMH as underpinned by the findings and recommendations of the 4th Civic Forum, which discussed questions related to work and employment.Results Updating the GMPMH in light of the Civic Forum underlines the need for a more inclusive type of governance regarding policy and systems transformation. Local communities and persons in recovery can reach each other to promote change and

  9. Control Properties of Bottom Fired Marine Boilers

    DEFF Research Database (Denmark)

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

    2005-01-01

    This paper focuses on model analysis of a dynamic model of a bottom fired one-pass smoke tube boiler. Linearised versions of the model are analysed to determine how gain, time constants and right half plane zeros (caused by the shrink-and-swell phenomenon) depend on the steam flow load. Furthermore...... the interactions in the system are inspected to analyse potential benefit from using a multivariable control strategy in favour of the current strategy based on single loop theory. An analysis of the nonlinear model is carried out to further determine the nonlinear characteristics of the boiler system...... and to verify whether nonlinear control is needed. Finally a controller based on single loop theory is used to analyse if input constraints become active when rejecting transient behaviour from the disturbance steam flow. The model analysis shows large variations in system gains at steady state as function...

  10. Coal reburning technology for cyclone boilers

    International Nuclear Information System (INIS)

    Yagiela, A.S.; Maringo, G.J.; Newell, R.J.; Farzan, H.

    1990-01-01

    Babcock and Wilcox has obtained encouraging results from engineering feasibility and pilot-scale proof-of-concept studies of coal reburning for cyclone boiler NO x control. Accordingly, B and W completed negotiations for a clean coal cooperative agreement with the Department of Energy to demonstrate coal reburning technology for cyclone boilers. The host site for the demonstration is the Wisconsin Power and Light (WP and L) Company's 100MWe Nelson Dewey Station. Reburning involves the injection of a supplemental fuel (natural gas, oil, or coal) into the main furnace to produce locally reducing stoichiometric conditions which convert the NO x produced therein to molecular nitrogen, thereby reducing overall NO x emissions. There are currently no commercially-demonstrated combustion modification techniques for cyclone boilers which reduce NO x emissions. The emerging reburning technology offers cyclone boiler operators a promising alternative to expensive flue gas cleanup techniques for NO x emission reduction. This paper reviews baseline testing results at the Nelson Dewey Station and pilot-scale results simulating Nelson Dewey operation using pulverized coal (PC) as the reburning fuel. Outcomes of the model studies as well as the full-scale demonstration preliminary design are discussed

  11. Boiler tube failure prevention in fossil fired boilers

    International Nuclear Information System (INIS)

    Townsend, R.D.

    1993-01-01

    It is the common experience of power generating companies worldwide that the main causes of forced outages on power plant are those due to boiler tube failures on fossil units. The main reason for the large number of failures are the severe environmental conditions in fossil boilers as the effects of stress, temperature, temperature gradients, corrosion, erosion and vibration combine to produce degradation of the tube steel. Corrosion by oxidation, by combustion products and by impure boiler water can significantly reduce the tube wall thickness and result in failure of a tube many years before its designed service life. Errors can also occur in the design manufacturer, storage, operation, and maintenance of boiler tubing and the wrong material installed in a critical location can lead to premature failure. Altogether, experts in the US and UK, from many different disciplines, have identified seven broad categories of boiler tube failure mechanisms. 1 tab., 2 figs

  12. Enhanced oil recovery by nanoparticles injection: Modeling and simulation

    KAUST Repository

    El-Amin, Mohamed; Sun, Shuyu; Salama, Amgad

    2013-01-01

    In the present paper, a mathematical model and numerical simulation to describe the nanoparticles-water suspension imbibes into a water-oil two-phase flow in a porous medium is introduced. We extend the model to include the negative capillary pressure and mixed relative permeabilities correlations to fit with the mixed-wet system. Also, buoyancy and capillary forces as well as Brownian diffusion are considered. Throughout this investigation, we monitor the changing of the fluids and solid properties due to addition of the nanoparticles and check for possible enhancement of the oil recovery process using numerical experiments.

  13. An optimising controller for Hinkley Point B AGR boilers

    International Nuclear Information System (INIS)

    Wells, C.

    1986-01-01

    The improvements to the control system at Hinkley Point 'B' Power Station has as one of its objectives the provision of a half unit valve controller. This will enable the asymmetry between the boiler half units, which is a feature of current operation, to be reduced. The use of an on-line boiler model in conjunction with this facility will allow the risk to the boilers from corrosion, creep, and vibration to be assessed and held at the minimum attainable value, thereby prolonging plant life whilst maximising output and efficiency. (author)

  14. Economical analyses of construction of a biomass boiler house

    International Nuclear Information System (INIS)

    Normak, A.

    2002-01-01

    To reduce the energy costs we can use cheaper fuel to fire our boiler. One of the cheapest fuels is wood biomass. It is very actual issue how to use cheaper wood biomass in heat generation to decrease energy costs and to increase biomass share in our energy balance. Before we decide to build biomass boiler house it is recommendable to analyse the economical situation and work out most profitable, efficient, reliable and ecological boiler plant design on particular conditions. The best way to perform the analyses is to use the economical model presented. It saves our time and gives objective evaluation to the project. (author)

  15. Improved nuclear boiler

    International Nuclear Information System (INIS)

    Pierart, Robert.

    1980-01-01

    The improved nuclear boiler concerned in this invention is of the kind comprising, inter alia, a nuclear reactor supported by a metallic structure and of which the vessel is at least enclosed in part by a casing acting as a protective containment integrated in this structure. It is essentially characterized in that this casing is fitted into and maintained in position in the metallic structure by removable locking devices which enable the casing to be withdrawn from the remainder of the structure. Hence, after the casing has been withdrawn or removed from the metallic structure, access to the reactor vessel is readily obtained for inspection and/or testing from without [fr

  16. Numerical investigation of ash deposition in straw-fired boilers

    DEFF Research Database (Denmark)

    Kær, Søren Knudsen

    in the design phase of straw-fired boilers. Some of the primary model outputs include improved heat transfer rate predictions and detailed information about local deposit formation rates. This information is essential when boiler availability and efficiency is to be estimated. A stand-alone program has been...... accumulation rates encountered during straw combustion in grate-fired boilers. The sub-models have been based on information about the combustion and deposition properties of straw gathered from the literature and combined into a single Computational Fluid Dynamics (CFD) based analysis tool which can aid...... transfer mechanisms have a pronounced influence on the combustion pattern. The combined set of sub-models has been evaluated using the straw-fired boiler at Masnedø CHP plant as a test case. The predicted grate combustion and KCl release patterns are in qualitative agreement with experimental findings...

  17. Modelling post-fire vegetation recovery in Portugal

    Directory of Open Access Journals (Sweden)

    A. Bastos

    2011-12-01

    Full Text Available Wildfires in Mediterranean Europe have been increasing in number and extension over the last decades and constitute one of the major disturbances of these ecosystems. Portugal is the country with more burnt area in the last decade and the years of 2003 and 2005 were particularly devastating, the total burned areas of 425 000 and 338 000 ha being several times higher than the corresponding average. The year of 2005 further coincided with one of the most severe droughts since early 20th century. Due to different responses of vegetation to diverse fire regimes and to the complexity of landscape structures, fires have complex effects on vegetation recovery. Remote sensing has revealed to be a powerful tool in studying vegetation dynamics and in monitoring post-fire vegetation recovery, which is crucial to land-management and to prevent erosion.

    The main goals of the present work are (i to assess the accuracy of a vegetation recovery model previously developed by the authors; (ii to assess the model's performance, namely its sensitivity to initial conditions, to the temporal length of the input dataset and to missing data; (iii to study vegetation recovery over two selected areas that were affected by two large wildfire events in the fire seasons of 2003 and 2005, respectively.

    The study relies on monthly values of NDVI over 11 years (1998–2009, at 1 km × 1 km spatial resolution, as obtained by the VEGETATION instrument. According to results from sensitivity analysis, the model is robust and able to provide good estimations of recovery times of vegetation when the regeneration process is regular, even when missing data is present. In respect to the two selected burnt scars, results indicate that fire damage is a determinant factor of regeneration, as less damaged vegetation recovers more rapidly, which is mainly justified by the high coverage of Pinus pinaster over the area, and by the fact that coniferous forests tend to

  18. Modelling post-fire vegetation recovery in Portugal

    Science.gov (United States)

    Bastos, A.; Gouveia, C. M.; Dacamara, C. C.; Trigo, R. M.

    2011-12-01

    Wildfires in Mediterranean Europe have been increasing in number and extension over the last decades and constitute one of the major disturbances of these ecosystems. Portugal is the country with more burnt area in the last decade and the years of 2003 and 2005 were particularly devastating, the total burned areas of 425 000 and 338 000 ha being several times higher than the corresponding average. The year of 2005 further coincided with one of the most severe droughts since early 20th century. Due to different responses of vegetation to diverse fire regimes and to the complexity of landscape structures, fires have complex effects on vegetation recovery. Remote sensing has revealed to be a powerful tool in studying vegetation dynamics and in monitoring post-fire vegetation recovery, which is crucial to land-management and to prevent erosion. The main goals of the present work are (i) to assess the accuracy of a vegetation recovery model previously developed by the authors; (ii) to assess the model's performance, namely its sensitivity to initial conditions, to the temporal length of the input dataset and to missing data; (iii) to study vegetation recovery over two selected areas that were affected by two large wildfire events in the fire seasons of 2003 and 2005, respectively. The study relies on monthly values of NDVI over 11 years (1998-2009), at 1 km × 1 km spatial resolution, as obtained by the VEGETATION instrument. According to results from sensitivity analysis, the model is robust and able to provide good estimations of recovery times of vegetation when the regeneration process is regular, even when missing data is present. In respect to the two selected burnt scars, results indicate that fire damage is a determinant factor of regeneration, as less damaged vegetation recovers more rapidly, which is mainly justified by the high coverage of Pinus pinaster over the area, and by the fact that coniferous forests tend to recover slower than transitional woodland

  19. Validity of the Neuromuscular Recovery Scale: a measurement model approach.

    Science.gov (United States)

    Velozo, Craig; Moorhouse, Michael; Ardolino, Elizabeth; Lorenz, Doug; Suter, Sarah; Basso, D Michele; Behrman, Andrea L

    2015-08-01

    To determine how well the Neuromuscular Recovery Scale (NRS) items fit the Rasch, 1-parameter, partial-credit measurement model. Confirmatory factor analysis (CFA) and principal components analysis (PCA) of residuals were used to determine dimensionality. The Rasch, 1-parameter, partial-credit rating scale model was used to determine rating scale structure, person/item fit, point-measure item correlations, item discrimination, and measurement precision. Seven NeuroRecovery Network clinical sites. Outpatients (N=188) with spinal cord injury. Not applicable. NRS. While the NRS met 1 of 3 CFA criteria, the PCA revealed that the Rasch measurement dimension explained 76.9% of the variance. Ten of 11 items and 91% of the patients fit the Rasch model, with 9 of 11 items showing high discrimination. Sixty-nine percent of the ratings met criteria. The items showed a logical item-difficulty order, with Stand retraining as the easiest item and Walking as the most challenging item. The NRS showed no ceiling or floor effects and separated the sample into almost 5 statistically distinct strata; individuals with an American Spinal Injury Association Impairment Scale (AIS) D classification showed the most ability, and those with an AIS A classification showed the least ability. Items not meeting the rating scale criteria appear to be related to the low frequency counts. The NRS met many of the Rasch model criteria for construct validity. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  20. Modelling the viability of heat recovery from combined sewers.

    Science.gov (United States)

    Abdel-Aal, M; Smits, R; Mohamed, M; De Gussem, K; Schellart, A; Tait, S

    2014-01-01

    Modelling of wastewater temperatures along a sewer pipe using energy balance equations and assuming steady-state conditions was achieved. Modelling error was calculated, by comparing the predicted temperature drop to measured ones in three combined sewers, and was found to have an overall root mean squared error of 0.37 K. Downstream measured wastewater temperature was plotted against modelled values; their line gradients were found to be within the range of 0.9995-1.0012. The ultimate aim of the modelling is to assess the viability of recovering heat from sewer pipes. This is done by evaluating an appropriate location for a heat exchanger within a sewer network that can recover heat without impacting negatively on the downstream wastewater treatment plant (WWTP). Long sewers may prove to be more viable for heat recovery, as heat lost can be reclaimed before wastewater reaching the WWTP.

  1. Electrostimulated recovery of welded joint durability: experiment and model

    International Nuclear Information System (INIS)

    Semakin, E.V.; Chirakadze, D.Z.; Tsellermaer, V.Ya.; Gromov, V.E.; Sosnin, O.V.

    1997-01-01

    The possibility to increase the durability of welded joints operating under conditions of low cycle fatigue is shown to be brought about using electric current pulses. Experimental method of recovery of operational capability is demonstrated on welded joints of tool steels R6M5 and 40Kh/ The onset of critical stage of fatigue in the welded joint was determined by ultrasonic testing. Then the specimens were treated with 20 Hz electric pulses with amplitude of 250 MA/M 2 for 100 μs. Such treatment resulted in an increase of time to fracture. The phenomenological model of the process is proposed

  2. Toward Balance Recovery With Leg Prostheses Using Neuromuscular Model Control

    Science.gov (United States)

    Geyer, Hartmut

    2016-01-01

    Objective Lower limb amputees are at high risk of falling as current prosthetic legs provide only limited functionality for recovering balance after unexpected disturbances. For instance, the most established control method used on powered leg prostheses tracks local joint impedance functions without taking the global function of the leg in balance recovery into account. Here we explore an alternative control policy for powered transfemoral prostheses that considers the global leg function and is based on a neuromuscular model of human locomotion. Methods We adapt this model to describe and simulate an amputee walking with a powered prosthesis using the proposed control, and evaluate the gait robustness when confronted with rough ground and swing leg disturbances. We then implement and partially evaluate the resulting controller on a leg prosthesis prototype worn by a non-amputee user. Results In simulation, the proposed prosthesis control leads to gaits that are more robust than those obtained by the impedance control method. The initial hardware experiments with the prosthesis prototype show that the proposed control reproduces normal walking patterns qualitatively and effectively responds to disturbances in early and late swing. However, the response to mid-swing disturbances neither replicates human responses nor averts falls. Conclusions The neuromuscular model control is a promising alternative to existing prosthesis controls, although further research will need to improve on the initial implementation and determine how well these results transfer to amputee gait. Significance This work provides a potential avenue for future development of control policies that help improve amputee balance recovery. PMID:26315935

  3. 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.

  4. 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.

  5. A study on the boiler efficiency influenced by the boiler operation parameter in fossil power plant

    International Nuclear Information System (INIS)

    Kwon, Y. S.; Suh, J. S.

    2002-01-01

    The main reason to analyze the boiler operation parameter in fossil power plant is to increase boiler high efficiency and energy saving movement in the government. This study intends to have trend and analyze the boiler efficiency influenced by the boiler parameter in sub-critical and super-critical type boiler

  6. 49 CFR 230.47 - Boiler number.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Boiler number. 230.47 Section 230.47..., 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...

  7. 30 CFR 77.413 - Boilers.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Boilers. 77.413 Section 77.413 Mineral... Mechanical Equipment § 77.413 Boilers. (a) Boilers shall be equipped with guarded, well-maintained water... the gages shall be kept clean and free of scale and rust. (b) Boilers shall be equipped with automatic...

  8. 30 CFR 56.13030 - Boilers.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Boilers. 56.13030 Section 56.13030 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13030 Boilers. (a) Fired pressure vessels (boilers) shall be equipped with water level gauges, pressure gauges...

  9. 30 CFR 57.13030 - Boilers.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Boilers. 57.13030 Section 57.13030 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Compressed Air and Boilers § 57.13030 Boilers. (a) Fired pressure vessels (boilers) shall be equipped with water level gauges, pressure...

  10. CFB boilers in multifuel application

    International Nuclear Information System (INIS)

    Goral, D.; Krzton, B.

    2007-01-01

    Fuel flexibility characteristic for CFB boilers plays an important rule in industrial and utility size applications. Possibility to use wider range of fuels that has been long time considered as by-products or wastes and possibility to design boilers able to operate with alternative fuels is an important factor that improves fuel delivery security and plant economy. Presented article is based on similar publications that present Foster Wheeler's experience in design and delivery of the CFB boilers for wide range of coals and cofiring by- products of crude oil refining and coal processing. Aspects of biomass cofiring will be also presented. (author)

  11. National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Institutional Boilers; Guidance for Calculating Efficiency Credits Resulting from Implementation of Energy Conservation Measures

    Energy Technology Data Exchange (ETDEWEB)

    Cox, Daryl [ORNL; Papar, Riyaz [Hudson Technologies; Wright, Dr. Anthony [ALW Consulting

    2013-02-01

    The purpose of this document is to provide guidance for developing a consistent approach to documenting efficiency credits generated from energy conservation measures in the Implementation Plan for boilers covered by the Boiler MACT rule (i.e., subpart DDDDD of CFR part 63). This document divides Boiler System conservation opportunities into four functional areas: 1) the boiler itself, 2) the condensate recovery system, 3) the distribution system, and 4) the end uses of the steam. This document provides technical information for documenting emissions credits proposed in the Implementation Plan for functional areas 2) though 4). This document does not include efficiency improvements related to the Boiler tune-ups.

  12. 46 CFR 61.05-10 - Boilers in service.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Boilers in service. 61.05-10 Section 61.05-10 Shipping... 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...

  13. 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

  14. 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

  15. Building a better methane generation model: Validating models with methane recovery rates from 35 Canadian landfills.

    Science.gov (United States)

    Thompson, Shirley; Sawyer, Jennifer; Bonam, Rathan; Valdivia, J E

    2009-07-01

    The German EPER, TNO, Belgium, LandGEM, and Scholl Canyon models for estimating methane production were compared to methane recovery rates for 35 Canadian landfills, assuming that 20% of emissions were not recovered. Two different fractions of degradable organic carbon (DOC(f)) were applied in all models. Most models performed better when the DOC(f) was 0.5 compared to 0.77. The Belgium, Scholl Canyon, and LandGEM version 2.01 models produced the best results of the existing models with respective mean absolute errors compared to methane generation rates (recovery rates + 20%) of 91%, 71%, and 89% at 0.50 DOC(f) and 171%, 115%, and 81% at 0.77 DOC(f). The Scholl Canyon model typically overestimated methane recovery rates and the LandGEM version 2.01 model, which modifies the Scholl Canyon model by dividing waste by 10, consistently underestimated methane recovery rates; this comparison suggested that modifying the divisor for waste in the Scholl Canyon model between one and ten could improve its accuracy. At 0.50 DOC(f) and 0.77 DOC(f) the modified model had the lowest absolute mean error when divided by 1.5 yielding 63 +/- 45% and 2.3 yielding 57 +/- 47%, respectively. These modified models reduced error and variability substantially and both have a strong correlation of r = 0.92.

  16. DBSSP - A computer program for simulation of controlled circulation boiler and natural circulation boiler start up behavior

    International Nuclear Information System (INIS)

    Li Bin; Chen Tingkuan; Yang Dong

    2005-01-01

    In this paper, a computer program, Drum Boiler Start-up Simulation Program (DBSSP), is developed for simulating the start up behavior of controlled circulation and natural circulation boilers. The mathematical model developed here is based on the first principles of mass, energy and momentum conservations. In the boiler model, heat transfer in the waterwall, the superheater, the reheater and the economizer is simulated by the distributing parameter method, while heat transfer in the drum and the downcomer is simulated by lumped parameter analysis. The program can provide detailed flow and thermodynamic characteristics of the boiler components. The development of this program is based only on design data, so it can be used for any subcritical, controlled or natural circulation boiler. The simulation results were compared with experimental measurements, and good agreements between them were found. This program is expected to be useful for predicting the characteristics and the performance of controlled circulation and natural circulation boilers during the start up process. It also can be used to optimize a start up system for minimum start up time

  17. 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.

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

    International Nuclear Information System (INIS)

    Pan Jie; Yang Dong; Chen Gongming; Zhou Xu; Bi Qincheng

    2012-01-01

    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.

  19. Optimal Switching Control of Burner Setting for a Compact Marine Boiler Design

    DEFF Research Database (Denmark)

    Solberg, Brian; Andersen, Palle; Maciejowski, Jan M.

    2010-01-01

    This paper discusses optimal control strategies for switching between different burner modes in a novel compact  marine boiler design. The ideal behaviour is defined in a performance index the minimisation of which defines an ideal trade-off between deviations in boiler pressure and water level...... approach is based on a generalisation of hysteresis control. The strategies are verified on a simulation model of the compact marine boiler for control of low/high burner load switches.  ...

  20. Piloted Simulation of a Model-Predictive Automated Recovery System

    Science.gov (United States)

    Liu, James (Yuan); Litt, Jonathan; Sowers, T. Shane; Owens, A. Karl; Guo, Ten-Huei

    2014-01-01

    This presentation describes a model-predictive automatic recovery system for aircraft on the verge of a loss-of-control situation. The system determines when it must intervene to prevent an imminent accident, resulting from a poor approach. It estimates the altitude loss that would result from a go-around maneuver at the current flight condition. If the loss is projected to violate a minimum altitude threshold, the maneuver is automatically triggered. The system deactivates to allow landing once several criteria are met. Piloted flight simulator evaluation showed the system to provide effective envelope protection during extremely unsafe landing attempts. The results demonstrate how flight and propulsion control can be integrated to recover control of the vehicle automatically and prevent a potential catastrophe.

  1. Advanced air/flue gas staging based on CFD modelling for enhanced combustion and burnout in a waste-wood fired boiler

    DEFF Research Database (Denmark)

    Rajh, Boštjan; Yin, Chungen; Samec, Niko

    2017-01-01

    The paper presents the impacts of the jet momentum, position and orientation of air and Recycled Flue Gas (RFG) streams on the performance of a grate-fired boiler burning waste wood via a comprehensive CFD-based parametric study. It is found that the air and RFG jets can be optimized to enhance m...

  2. The Alternative Peer Group: A Developmentally Appropriate Recovery Support Model for Adolescents.

    Science.gov (United States)

    Nash, Angela; Collier, Crystal

    2016-01-01

    Recovery as the goal for substance use disorder treatment has been a key component of the Substance Abuse and Mental Health Services Administration's mission for the past decade. Consistent with their mission, there is a call for research and development of recovery-oriented systems of care to support affected individuals through all stages of the recovery process. Evidence is emerging to support recovery practice and research for adults, but recovery-oriented models for adolescents are scant. The Alternative Peer Group (APG) is a comprehensive adolescent recovery support model that integrates recovering peers and prosocial activities into evidence-based clinical practice. Employing APG participants' own words, this article will describe the essential elements and three theoretical frameworks underlying the APG model to illustrate how the APG serves as a developmentally appropriate recovery support service for adolescents with substance use disorder.

  3. Boiler using combustible fluid

    Science.gov (United States)

    Baumgartner, H.; Meier, J.G.

    1974-07-03

    A fluid fuel boiler is described comprising a combustion chamber, a cover on the combustion chamber having an opening for introducing a combustion-supporting gaseous fluid through said openings, means to impart rotation to the gaseous fluid about an axis of the combustion chamber, a burner for introducing a fluid fuel into the chamber mixed with the gaseous fluid for combustion thereof, the cover having a generally frustro-conical configuration diverging from the opening toward the interior of the chamber at an angle of between 15/sup 0/ and 55/sup 0/; means defining said combustion chamber having means defining a plurality of axial hot gas flow paths from a downstream portion of the combustion chamber to flow hot gases into an upstream portion of the combustion chamber, and means for diverting some of the hot gas flow along paths in a direction circumferentially of the combustion chamber, with the latter paths being immersed in the water flow path thereby to improve heat transfer and terminating in a gas outlet, the combustion chamber comprising at least one modular element, joined axially to the frustro-conical cover and coaxial therewith. The modular element comprises an inner ring and means of defining the circumferential, radial, and spiral flow paths of the hot gases.

  4. Modeling a Thermoelectric Generator Applied to Diesel Automotive Heat Recovery

    Science.gov (United States)

    Espinosa, N.; Lazard, M.; Aixala, L.; Scherrer, H.

    2010-09-01

    Thermoelectric generators (TEGs) are outstanding devices for automotive waste heat recovery. Their packaging, lack of moving parts, and direct heat to electrical conversion are the main benefits. Usually, TEGs are modeled with a constant hot-source temperature. However, energy in exhaust gases is limited, thus leading to a temperature decrease as heat is recovered. Therefore thermoelectric properties change along the TEG, affecting performance. A thermoelectric generator composed of Mg2Si/Zn4Sb3 for high temperatures followed by Bi2Te3 for low temperatures has been modeled using engineering equation solver (EES) software. The model uses the finite-difference method with a strip-fins convective heat transfer coefficient. It has been validated on a commercial module with well-known properties. The thermoelectric connection and the number of thermoelements have been addressed as well as the optimum proportion of high-temperature material for a given thermoelectric heat exchanger. TEG output power has been estimated for a typical commercial vehicle at 90°C coolant temperature.

  5. Materials and boiler rig testing to support chemical cleaning of once-through AGR boilers

    International Nuclear Information System (INIS)

    Tice, D.R.; Platts, N.; Raffel, A.S.; Rudge, A.

    2002-01-01

    chosen. This paper describes the results of the latter two activities: additional materials testing necessary to support a full scale plant clean and the trial clean on a model boiler rig replicating a single boiler tube together with the pre- and post-clean thermohydraulic behaviour. (authors)

  6. Simulation study on the maximum continuous working condition of a power plant boiler

    Science.gov (United States)

    Wang, Ning; Han, Jiting; Sun, Haitian; Cheng, Jiwei; Jing, Ying'ai; Li, Wenbo

    2018-05-01

    First of all, the boiler is briefly introduced to determine the mathematical model and the boundary conditions, then the boiler under the BMCR condition numerical simulation study, and then the BMCR operating temperature field analysis. According to the boiler actual test results and the hot BMCR condition boiler output test results, the simulation results are verified. The main conclusions are as follows: the position and size of the inscribed circle in the furnace and the furnace temperature distribution and test results under different elevation are compared and verified; Accuracy of numerical simulation results.

  7. Mathematical model of tuberculosis epidemic with recovery time delay

    Science.gov (United States)

    Iskandar, Taufiq; Chaniago, Natasya Ayuningtia; Munzir, Said; Halfiani, Vera; Ramli, Marwan

    2017-12-01

    Tuberculosis (TB) is a contagious disease which can cause death. The disease is caused by Mycobacterium Tuberculosis which generally affects lungs and other organs such as lymph gland, intestine, kidneys, uterus, bone, and brain. The spread of TB occurs through the bacteria-contaminated air which is inhaled into the lungs. The symptoms of the TB patients are cough, chest pain, shortness of breath, appetite lose, weight lose, fever, cold, and fatigue. World Health Organization (WHO) reported that Indonesia placed the second in term of the most TB cases after India which has 23 % cases while China is reported to have 10 % cases in global. TB has become one of the greatest death threats in global. One way to countermeasure TB disease is by administering vaccination. However, a medication is needed when one has already infected. The medication can generally take 6 months of time which consists of two phases, inpatient and outpatient. Mathematical models to analyze the spread of TB have been widely developed. One of them is the SEIR type model. In this model the population is divided into four groups, which are suspectible (S), exposed (S), infected (I), recovered (R). In fact, a TB patient needs to undergo medication with a period of time in order to recover. This article discusses a model of TB spread with considering the term of recovery (time delay). The model is developed in SIR type where the population is divided into three groups, suspectible (S), infected (I), and recovered (R). Here, the vaccine is given to the susceptible group and the time delay is considered in the group undergoing the medication.

  8. Bond and CDS Pricing via the Stochastic Recovery Black-Cox Model

    Directory of Open Access Journals (Sweden)

    Albert Cohen

    2017-04-01

    Full Text Available Building on recent work incorporating recovery risk into structural models by Cohen & Costanzino (2015, we consider the Black-Cox model with an added recovery risk driver. The recovery risk driver arises naturally in the context of imperfect information implicit in the structural framework. This leads to a two-factor structural model we call the Stochastic Recovery Black-Cox model, whereby the asset risk driver At defines the default trigger and the recovery risk driver Rt defines the amount recovered in the event of default. We then price zero-coupon bonds and credit default swaps under the Stochastic Recovery Black-Cox model. Finally, we compare our results with the classic Black-Cox model, give explicit expressions for the recovery risk premium in the Stochastic Recovery Black-Cox model, and detail how the introduction of separate but correlated risk drivers leads to a decoupling of the default and recovery risk premiums in the credit spread. We conclude this work by computing the effect of adding coupons that are paid continuously until default, and price perpetual (consol bonds in our two-factor firm value model, extending calculations in the seminal paper by Leland (1994.

  9. 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.

  10. Failure analysis of boiler tube

    International Nuclear Information System (INIS)

    Mehmood, K.; Siddiqui, A.R.

    2007-01-01

    Boiler tubes are energy conversion components where heat energy is used to convert water into high pressure superheated steam, which is then delivered to a turbine for electric power generation in thermal power plants or to run plant and machineries in a process or manufacturing industry. It was reported that one of the tubes of a fire-tube boiler used in a local industry had leakage after the formation of pits at the external surface of the tube. The inner side of the fire tube was working with hot flue gasses with a pressure of 10 Kg/cm/sup 2/ and temperature 225 degree C. The outside of the tube was surrounded by feed water. The purpose of this study was to determine the cause of pits developed at the external surface of the failed boiler tube sample. In the present work boiler tube samples of steel grade ASTM AI61/ASTM A192 were analyzed using metallographic analysis, chemical analysis, and mechanical testing. It was concluded that the appearance of defects on the boiler tube sample indicates cavitation type corrosion failure. Cavitation damage superficially resembled pitting, but surface appeared considerably rougher and had many closely spaced pits. (author)

  11. Analysis of a waste-heat boiler by CFD simulation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yongziang; Jokilaakso, A. [Helsinki Univ. of Technology, Otaniemi (Finland)

    1996-12-31

    Waste-heat boilers play important roles in the continuous operation of a smelter and in the conservation of energy. However, the fluid flow and heat transfer behaviour has not been well studied, concerning the boiler performance and design. This presentation describes simulated gas flow and heat transfer of a waste-heat boiler in the Outokumpu copper flash smelting process. The governing transport equations for the conservation of mass, momentum and enthalpy were solved with a commercial CFD-code PHOENICS. The standard k-{epsilon} turbulence model and a composite-flux radiation model were used in the computations. The computational results show that the flow is strongly recirculating and distinctly three-dimensional in most part of the boiler, particularly in the radiation section. The predicted flow pattern and temperature distribution were in a good agreement with laboratory models and industrial measurements. The results provide detailed information of flow pattern, the temperature distribution and gas cooling efficiency. The CFD proved to be a useful tool in analysing the boiler operation. (author)

  12. Analysis of a waste-heat boiler by CFD simulation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yongziang; Jokilaakso, A [Helsinki Univ. of Technology, Otaniemi (Finland)

    1997-12-31

    Waste-heat boilers play important roles in the continuous operation of a smelter and in the conservation of energy. However, the fluid flow and heat transfer behaviour has not been well studied, concerning the boiler performance and design. This presentation describes simulated gas flow and heat transfer of a waste-heat boiler in the Outokumpu copper flash smelting process. The governing transport equations for the conservation of mass, momentum and enthalpy were solved with a commercial CFD-code PHOENICS. The standard k-{epsilon} turbulence model and a composite-flux radiation model were used in the computations. The computational results show that the flow is strongly recirculating and distinctly three-dimensional in most part of the boiler, particularly in the radiation section. The predicted flow pattern and temperature distribution were in a good agreement with laboratory models and industrial measurements. The results provide detailed information of flow pattern, the temperature distribution and gas cooling efficiency. The CFD proved to be a useful tool in analysing the boiler operation. (author)

  13. Numerical simulation of a small-scale biomass boiler

    International Nuclear Information System (INIS)

    Collazo, J.; Porteiro, J.; Míguez, J.L.; Granada, E.; Gómez, M.A.

    2012-01-01

    Highlights: ► Simplified model for biomass combustion was developed. ► Porous zone conditions are used in the bed. ► Model is fully integrated in a commercial CFD code to simulate a small scale pellet boiler. ► Pollutant emissions are well predicted. ► Simulation provides extensive information about the behaviour of the boiler. - Abstract: This paper presents a computational fluid dynamic simulation of a domestic pellet boiler. Combustion of the solid fuel in the burner is an important issue when discussing the simulation of this type of system. A simplified method based on a thermal balance was developed in this work to introduce the effects provoked by pellet combustion in the boiler simulation. The model predictions were compared with the experimental measurements, and a good agreement was found. The results of the boiler analysis show that the position of the water tubes, the distribution of the air inlets and the air infiltrations are the key factors leading to the high emission levels present in this type of system.

  14. Computational modeling and analysis of heavy water losses in boiler blow down with different positions of BBW-V100 at KANUPP

    International Nuclear Information System (INIS)

    Maqbool, M. U.

    2012-01-01

    The term blowdown is referred to the boilers and steam generators. Blowing down water from the steam generators maintains the chemistry of the feedwater and helps prevent scaling or sludge formation. In a nuclear power plant, the primary loop contains some activity in the form of tritium content. In boilers, primary and secondary systems interface and due to the pressure difference there is always a chance of mixing of primary and secondary fluids in event of tube leak. This primary fluid i.e., heavy water in our case can be lost through the blowdown lines after mixing with the feedwater. This thesis is a computational work for the determination of heavy water losses through the blowdown lines. (author)

  15. Detection and rapid recovery of the Sutter's Mill meteorite fall as a model for future recoveries worldwide

    Science.gov (United States)

    Fries, Marc; Le Corre, Lucille; Hankey, Mike; Fries, Jeff; Matson, Robert; Schaefer, Jake; Reddy, Vishnu

    2014-11-01

    The Sutter's Mill C-type meteorite fall occurred on 22 April 2012 in and around the town of Coloma, California. The exact location of the meteorite fall was determined within hours of the event using a combination of eyewitness reports, weather radar imagery, and seismometry data. Recovery of the first meteorites occurred within 2 days and continued for months afterward. The recovery effort included local citizens, scientists, and meteorite hunters, and featured coordination efforts by local scientific institutions. Scientific analysis of the collected meteorites revealed characteristics that were available for study only because the rapid collection of samples had minimized terrestrial contamination/alteration. This combination of factors—rapid and accurate location of the event, participation in the meteorite search by the public, and coordinated scientific investigation of recovered samples—is a model that was widely beneficial and should be emulated in future meteorite falls. The tools necessary to recreate the Sutter's Mill recovery are available, but are currently underutilized in much of the world. Weather radar networks, scientific institutions with interest in meteoritics, and the interested public are available globally. Therefore, it is possible to repeat the Sutter's Mill recovery model for future meteorite falls around the world, each for relatively little cost with a dedicated researcher. Doing so will significantly increase the number of fresh meteorite falls available for study, provide meteorite material that can serve as the nuclei of new meteorite collections, and will improve the public visibility of meteoritics research.

  16. Concept of Heat Recovery from Exhaust Gases

    Science.gov (United States)

    Bukowska, Maria; Nowak, Krzysztof; Proszak-Miąsik, Danuta; Rabczak, Sławomir

    2017-10-01

    The theme of the article is to determine the possibility of waste heat recovery and use it to prepare hot water. The scope includes a description of the existing sample of coal-fired boiler plant, the analysis of working condition and heat recovery proposals. For this purpose, a series of calculations necessary to identify the energy effect of exhaust temperature decreasing and transferring recovery heat to hot water processing. Heat recover solutions from the exhaust gases channel between boiler and chimney section were proposed. Estimation for the cost-effectiveness of such a solution was made. All calculations and analysis were performed for typical Polish conditions, for coal-fired boiler plant. Typicality of this solution is manifested by the volatility of the load during the year, due to distribution of heat for heating and hot water, determining the load variation during the day. Analysed system of three boilers in case of load variation allows to operational flexibility and adaptation of the boilers load to the current heat demand. This adaptation requires changes in the operating conditions of boilers and in particular assurance of properly conditions for the combustion of fuel. These conditions have an impact on the existing thermal loss and the overall efficiency of the boiler plant. On the boiler plant efficiency affects particularly exhaust gas temperature and the excess air factor. Increasing the efficiency of boilers plant is possible to reach by following actions: limiting the excess air factor in coal combustion process in boilers and using an additional heat exchanger in the exhaust gas channel outside of boilers (economizer) intended to preheat the hot water.

  17. Design, empirical modelling and analysis of a waste-heat recovery system coupled to a traditional cooking stove

    International Nuclear Information System (INIS)

    Sakdanuphab, Rachsak; Sakulkalavek, Aparporn

    2017-01-01

    Highlights: • WHR system was implemented to utilise the waste heat from a stove. • The empirical modelling by RSM can be used to predict the generated TEG power. • The total conversion efficiency of the WHR system was more than 80%. • The stove efficiency decreased less than 5% when the WHR system was attached. - Abstract: In this work, a waste-heat recovery (WHR) system was designed and implemented to utilise the waste heat from a cooking stove. The WHR system was designed to preserve maximum thermal energy efficiency, use passive cooling, and produce a system that did not alter the body of the cooking stove. The thermal energy from the cooking stove was converted into electrical energy by a thermoelectric generator (TEG) and used in a waste-heat hot water boiler. The cold side of the TEG was cooled by heat pipes immersed in a water box that offers a high heat transfer rate. The heated water can be used for domestic purposes. Dependent variables were the heater temperature and the volume of water. The heater temperature was varied between 130 and 271 °C, and 4.2–9.5 L of water was investigated. At equilibrium, response surface methodology based on a central composite design was used to empirically model the influence of the heater temperature and the volume of water on the electrical power generation and the hot water temperature. Experimental results of the system efficiency showed that the heater temperature was more influential than was the volume of water. The total efficiency of the WHR system was more than 80%. Thermal contact resistance was analysed to improve the WHR system performance. Finally, the thermal efficiency of a cooking stove, both with and without the WHR system, was measured. Results showed that the thermal efficiency of the cooking stove decreased by less than 5% when the WHR system was attached.

  18. Optimizing the Integrated Design of Boilers - Simulation

    DEFF Research Database (Denmark)

    Sørensen, K.; Karstensen, C.; Condra, T.

    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...

  19. Market potential of solar thermal enhanced oil recovery-a techno-economic model for Issaran oil field in Egypt

    Science.gov (United States)

    Gupta, Sunay; Guédez, Rafael; Laumert, Björn

    2017-06-01

    Solar thermal enhanced oil recovery (S-EOR) is an advanced technique of using concentrated solar power (CSP) technology to generate steam and recover oil from maturing oil reservoirs. The generated steam is injected at high pressure and temperature into the reservoir wells to facilitate oil production. There are three common methods of steam injection in enhanced oil recovery - continuous steam injection, cyclic steam stimulation (CSS) and steam assisted gravity drainage (SAGD). Conventionally, this steam is generated through natural gas (NG) fired boilers with associated greenhouse gas emissions. However, pilot projects in the USA (Coalinga, California) and Oman (Miraah, Amal) demonstrated the use of S-EOR to meet their steam requirements despite the intermittent nature of solar irradiation. Hence, conventional steam based EOR projects under the Sunbelt region can benefit from S-EOR with reduced operational expenditure (OPEX) and increased profitability in the long term, even with the initial investment required for solar equipment. S-EOR can be realized as an opportunity for countries not owning any natural gas resources to make them less energy dependent and less sensible to gas price fluctuations, and for countries owning natural gas resources to reduce their gas consumption and export it for a higher margin. In this study, firstly, the market potential of S-EOR was investigated worldwide by covering some of the major ongoing steam based EOR projects as well as future projects in pipeline. A multi-criteria analysis was performed to compare local conditions and requirements of all the oil fields based on a defined set of parameters. Secondly, a modelling approach for S-EOR was designed to identify cost reduction opportunities and optimum solar integration techniques, and the Issaran oil field in Egypt was selected for a case study to substantiate the approach. This modelling approach can be consulted to develop S-EOR projects for any steam flooding based oil

  20. MULTIPLE LINEAR REGRESSION ANALYSIS FOR PREDICTION OF BOILER LOSSES AND BOILER EFFICIENCY

    OpenAIRE

    Chayalakshmi C.L

    2018-01-01

    MULTIPLE LINEAR REGRESSION ANALYSIS FOR PREDICTION OF BOILER LOSSES AND BOILER EFFICIENCY ABSTRACT Calculation of boiler efficiency is essential if its parameters need to be controlled for either maintaining or enhancing its efficiency. But determination of boiler efficiency using conventional method is time consuming and very expensive. Hence, it is not recommended to find boiler efficiency frequently. The work presented in this paper deals with establishing the statistical mo...

  1. Recovery Kinetics in Commercial Purity Aluminum Deformed to Ultrahigh Strain: Model and Experiment

    DEFF Research Database (Denmark)

    Yu, Tianbo; Hansen, Niels

    2016-01-01

    A new approach to analyze recovery kinetics is developed from a recent model, and microstructural observations are introduced to supplement hardness measurements. The approach involves two steps of data fitting, and the second step of fitting enables an estimation of the apparent activation energy...... for recovery. This approach is applied to commercial purity aluminum (AA1050) cold rolled to ultrahigh strain (99.6 pct reduction in thickness) and annealed at temperatures from 413 K to 493 K (140 A degrees C to 220 A degrees C). The annealing data fit the recovery model well, and the analysis shows...... that the apparent activation energy increases during recovery and approaches 190 kJ/mol at the end of recovery, suggesting that solute drag is an important rate-controlling mechanism. The recovery rate for the highly strained Al is found to be higher than that for Al deformed to a lower strain, an effect which...

  2. Multiloop control of a drum boiler

    Directory of Open Access Journals (Sweden)

    Alena Kozáková

    2014-05-01

    Full Text Available The Equivalent Subsystems Method (ESM (Kozáková et al., 2011 is methodology of decentralized controller design in the frequency domain which allows designing local controllers using any SISO frequency domain method. The paper deals with the digital ESM version where digital local PID controllers guaranteeing required performance for the full system are designed for individual equivalent subsystems using the practice-oriented Sine-wave method (Bucz et al., 2012. The proposed decentralized controller design procedure was verified on the nonlinear benchmark drum boiler simulation model (Morilla, 2012.

  3. A Mixed Bi-level Model to Correspond Service Recovery Chain

    OpenAIRE

    Abdolalipour, Amirhossein; Nazemi, Jamshid; Eshlaghi, Abbas Toloie; Lotfi, Farhad Hosseinzadeh

    2017-01-01

    In the competitive environment, minimizing time space between service failure perception and service recovery with lowest cost is one of fast responsiveness company’s requirements. In this article, modeling service failure response time is considered. It was not only service recovery chain profit optimization carefully planned but also satisfaction of consumers who disturbed by a service failure was considered profoundly. Inconsistency between optimization of service recovery chain’s total be...

  4. A crisis recovery model for adolescents with severe mental health problems.

    Science.gov (United States)

    Kaplan, Tony; Racussen, Lisa

    2013-04-01

    A model of intervention at the interface and for the in-patient phase for adolescents with severe mental health crises was developed to reduce length of stay while maintaining quality of service consonant with the 'recovery model'. The model is described, and discussed in the context of the limited literature on both crisis intervention with adolescents and families, and 'recovery' in this age-group. The model may be suitable also for use by community teams dealing with adolescents in crisis.

  5. Analysis of residual swirl in tangentially-fired natural gas-boiler

    International Nuclear Information System (INIS)

    Hasril Hasini; Muhammad Azlan Muad; Mohd Zamri Yusoff; Norshah Hafeez Shuaib

    2010-01-01

    This paper describes the investigation on residual swirl flow in a 120 MW natural gas, full-scale, tangential-fired boiler. Emphasis is given towards the understanding of the behavior of the combustion gas flow pattern and temperature distribution as a result of the tangential firing system of the boiler. The analysis was carried out based on three-dimensional computational modeling on full scale boiler with validation from key design parameter as well as practical observation. Actual operating parameters of the actual boiler are taken as the boundary conditions for this modeling. The prediction of total heat flux was found to be in agreement with the key design parameter while the residual swirl predicted at the upper furnace agrees qualitatively with the practical observation. Based on this comparison, detail analysis was carried out for comprehensive understanding on the generation and destruction of the residual swirl behavior in boiler especially those with high capacity. (author)

  6. Numerical simulation of a 374 tons/h water-tube steam boiler following a feedwater line break

    International Nuclear Information System (INIS)

    Deghal Cheridi, Amina Lyria; Chaker, Abla; Loubar, Ahcène

    2016-01-01

    Highlights: • We simulate the behavior of a steam boiler during feed-water line break accident. • To perform accident analysis of the steam boiler, Relap5/Mod3.2 system code is used. • A Relap5 model of the boiler is developed and qualified at the steady state level. • A good agreement between Relap5 results and available experimental data. • The Relap5 model predicts well the main transient features of the boiler. - Abstract: To ensure the operational safety of an industrial water-tube steam boiler it is very important to assess various accident scenarios in real plant working conditions. One of the most challenging scenarios is the loss of feedwater to the steam boiler. In this paper, a simulation of the behavior of an industrial water-tube radiant steam boiler during feedwater line break accident is discussed. The simulation is carried out using the RELAP5 system code. The steam boiler is installed in an Algerian natural gas liquefaction complex. The simulation shows the capabilities of RELAP5 system code in predicting the behavior of the steam boiler at both steady state and transient working conditions. From another side, the behavior of the steam boiler following the accident shows how the control system can successfully mitigate the effects and consequences of such accident and how the evaporator tubes can undergo a severe damage due to an uncontrolled increase of the wall temperature in case of failure of this system.

  7. DEVELOPMENT OF BIOSURFACTANT-MEDIATED OIL RECOVERY IN MODEL POROUS SYSTEMS AND COMPUTER SIMULATIONS OF BIOSURFACTANT-MEDIATED OIL RECOVERY

    Energy Technology Data Exchange (ETDEWEB)

    M.J. McInerney; S.K. Maudgalya; R. Knapp; M. Folmsbee

    2004-05-31

    Current technology recovers only one-third to one-half of the oil that is originally present in an oil reservoir. Entrapment of petroleum hydrocarbons by capillary forces is a major factor that limits oil recovery (1, 3, 4). Hydrocarbon displacement can occur if interfacial tension (IFT) between the hydrocarbon and aqueous phases is reduced by several orders of magnitude. Microbially-produced biosurfactants may be an economical method to recover residual hydrocarbons since they are effective at low concentrations. Previously, we showed that substantial mobilization of residual hydrocarbon from a model porous system occurs at biosurfactant concentrations made naturally by B. mojavensis strain JF-1 if a polymer and 2,3-butanediol were present (2). In this report, we include data on oil recovery from Berea sandstone experiments along with our previous data from sand pack columns in order to relate biosurfactant concentration to the fraction of oil recovered. We also investigate the effect that the JF-2 biosurfactant has on interfacial tension (IFT). The presence of a co-surfactant, 2,3-butanediol, was shown to improve oil recoveries possibly by changing the optimal salinity concentration of the formulation. The JF-2 biosurfactant lowered IFT by nearly 2 orders of magnitude compared to typical values of 28-29 mN/m. Increasing the salinity increased the IFT with or without 2,3-butanediol present. The lowest interfacial tension observed was 0.1 mN/m. Tertiary oil recovery experiments showed that biosurfactant solutions with concentrations ranging from 10 to 60 mg/l in the presence of 0.1 mM 2,3-butanediol and 1 g/l of partially hydrolyzed polyacrylamide (PHPA) recovered 10-40% of the residual oil present in Berea sandstone cores. When PHPA was used alone, about 10% of the residual oil was recovered. Thus, about 10% of the residual oil recovered in these experiments was due to the increase in viscosity of the displacing fluid. Little or no oil was recovered at

  8. 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...

  9. Model predictive control of a waste heat recovery system for automotive diesel engines

    NARCIS (Netherlands)

    Feru, E.; Willems, F.P.T.; de Jager, A.G.; Steinbuch, M.

    2014-01-01

    In this paper, a switching Model Predictive Control strategy is designed for an automotive Waste Heat Recovery system with two parallel evaporators. The objective is to maximize Waste Heat Recovery system output power, while satisfying safe operation under highly dynamic disturbances from the

  10. Fostering Recovery from Life-Transforming Mental Health Disorders: A Synthesis and Model.

    Science.gov (United States)

    Green, Carla A

    2004-11-01

    In the past, "recovery" from serious mental health problems has been variously defined and generally considered rare. Current evidence suggests that some form of recovery is both possible and common, yet we know little about the processes that differentiate those who recover from those who do not. This paper discusses approaches to defining recovery, proposes a model for fostering, understanding, and studying recovery, and suggests questions for clinicians, researchers, and policy makers. The proposed model is a synthesis of work from the field of mental health as well as from other disciplines. Environment, resources, and strains, provide the backdrop for recovery; core recovery processes include development, learning, healing, and their primary behavioral manifestation, adaptation. Components facilitating recovery include sources of motivation (hope, optimism, and meaning), prerequisites for action (agency, control, and autonomy), and capacity (competence and dysfunction). Attending to these aspects of the recovery process could help shape clinical practice, and systems that provide and finance mental health care, in ways that promote recovery.

  11. A Narrative Model of Recovery | Kelland | South African Journal of ...

    African Journals Online (AJOL)

    In this paper I defend the suggestion that narratively understanding her experience of rape can help a survivor in her recovery from the harm that she has suffered. Susan Brison defends a similar suggestion, but, I argue, does not get all of the possible mileage out of narrative understanding because she does not explore ...

  12. Wellness Circles: The Alkali Lake Model in Community Recovery Processes.

    Science.gov (United States)

    Ben, Leon W.; And Others

    The case study described here was conducted as a doctoral research project at Northern Arizona University. The study documents the success of the Shuswop Indian Band of Alkali Lake, British Columbia (Canada), in their 15-year battle with alcoholism, once the people themselves decided on recovery. The study looks back at the 95 percent recovery…

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

    International Nuclear Information System (INIS)

    Bull, A.; Owen, J.; Quirk, G.; G, Lewis; Rudge, A.; Woolsey, I.S.

    2012-09-01

    corrosion damage to the Type 316 superheater sections in the affected units an extensive programme of test work and plant modelling has been undertaken over a number of years. This has involved stress corrosion test work using full scale plant boiler simulations under a variety of feedwater chemistry conditions for both helical and serpentine boilers. Data from these investigations has then been used to construct models of the damage process that allow the risk of tube leaks due to stress corrosion cracking to be assessed. These models use plant feedwater chemistry and thermal-hydraulic data as inputs. The paper describes investigations of the risk of stress corrosion cracking in AGR boilers and the improvements in feedwater quality of the affected units to help mitigate the risk. (authors)

  14. Biomass boiler still best choice

    International Nuclear Information System (INIS)

    Wallace, Paula

    2014-01-01

    Full text: The City of Mount Gambier upgraded its boiler in September after analysis showed that biomass was still the optimal energy option. The Mount Gambier Aquatic Centre was built by the local city council in the 1980s as an outdoor pool facility for the public. The complex has three pools — an Olympic-sized, toddler and a learner pool — for a total volume of 1.38ML (including balance tanks). The large pool is heated to 27-28°C, the smaller one 30-32°C. From the very beginning, the pool water was heated by a biomass boiler, and via two heat exchangers whose combined capacity is 520 kW. The original biomass boiler ran on fresh sawdust from a local timber mill. After thirty years of dedicated service the original boiler had become unreliable and difficult to operate. Replacement options were investigated and included a straight gas boiler, a combined solar hot water and gas option, and biomass boilers. The boiler only produces heat, not electricity. All options were subjected to a triple bottom line assessment, which included potential capital costs, operating costs, community and environmental benefits and costs. The project was also assessed using a tool developed by Mount Gambier City Council that considers the holistic benefits — the CHAT Tool, which stands for Comprehensive Holistic Assessment Tool. “Basically it is a survey that covers environmental, social, economic and governance factors,” the council's environmental sustainability officer, Aaron Izzard told WME. In relation to environmental considerations, the kinds of questions explored by the CHAT Tool included: Sustainable use of resources — objective is to reduce council's dependence on non-renewable resources; Greenhouse emissions — objective is to reduce council's contribution of GHG into the atmosphere; Air quality — objective is to improve local air quality. The conclusion of these analyses was that while a biomass boiler would have a higher capital cost than a straight gas

  15. A system dynamics approach to develop a recovery model in the Malaysian automotive industry

    Science.gov (United States)

    Mohamad-Ali, N.; Ghazilla, R. A. R.; Abdul-Rashid, S. H.; Sakundarini, N.; Ahmad-Yazid, A.; Stephenie, L.

    2017-06-01

    Design strategies play a significant role to enhance recovery effectiveness at the end of product life cycle. By reviewing previous study, there are many factors involved to enhance recovery effectiveness but limited to linking design strategies factors in holistic and dynamics view. Proposed method are explained and an initial model for end-of-life vehicles (ELVs) recovery model illustrated in graphical and numerical data is presented. However this is limited to authors understanding and preliminary data which requires collaboration between designers and other stakeholders to develop a model based on actual situation.

  16. Modeling Soil Quality Thresholds to Ecosystem Recovery at Fort Benning, Georgia, USA

    Energy Technology Data Exchange (ETDEWEB)

    Garten Jr., C.T.

    2004-03-08

    The objective of this research was to use a simple model of soil C and N dynamics to predict nutrient thresholds to ecosystem recovery on degraded soils at Fort Benning, Georgia, in the southeastern USA. The model calculates aboveground and belowground biomass, soil C inputs and dynamics, soil N stocks and availability, and plant N requirements. A threshold is crossed when predicted soil N supplies fall short of predicted N required to sustain biomass accrual at a specified recovery rate. Four factors were important to development of thresholds to recovery: (1) initial amounts of aboveground biomass, (2) initial soil C stocks (i.e., soil quality), (3) relative recovery rates of biomass, and (4) soil sand content. Thresholds to ecosystem recovery predicted by the model should not be interpreted independent of a specified recovery rate. Initial soil C stocks influenced the predicted patterns of recovery by both old field and forest ecosystems. Forests and old fields on soils with varying sand content had different predicted thresholds to recovery. Soil C stocks at barren sites on Fort Benning generally lie below predicted thresholds to 100% recovery of desired future ecosystem conditions defined on the basis of aboveground biomass (18000 versus 360 g m{sup -2} for forests and old fields, respectively). Calculations with the model indicated that reestablishment of vegetation on barren sites to a level below the desired future condition is possible at recovery rates used in the model, but the time to 100% recovery of desired future conditions, without crossing a nutrient threshold, is prolonged by a reduced rate of forest growth. Predicted thresholds to ecosystem recovery were less on soils with more than 70% sand content. The lower thresholds for old field and forest recovery on more sandy soils are apparently due to higher relative rates of net soil N mineralization in more sandy soils. Calculations with the model indicate that a combination of desired future

  17. Multivariable robust adaptive sliding mode control of an industrial boiler-turbine in the presence of modeling imprecisions and external disturbances: A comparison with type-I servo controller.

    Science.gov (United States)

    Ghabraei, Soheil; Moradi, Hamed; Vossoughi, Gholamreza

    2015-09-01

    To guarantee the safety and efficient performance of the power plant, a robust controller for the boiler-turbine unit is needed. In this paper, a robust adaptive sliding mode controller (RASMC) is proposed to control a nonlinear multi-input multi-output (MIMO) model of industrial boiler-turbine unit, in the presence of unknown bounded uncertainties and external disturbances. To overcome the coupled nonlinearities and investigate the zero dynamics, input-output linearization is performed, and then the new decoupled inputs are derived. To tackle the uncertainties and external disturbances, appropriate adaption laws are introduced. For constructing the RASMC, suitable sliding surface is considered. To guarantee the sliding motion occurrence, appropriate control laws are constructed. Then the robustness and stability of the proposed RASMC is proved via Lyapunov stability theory. To compare the performance of the purposed RASMC with traditional control schemes, a type-I servo controller is designed. To evaluate the performance of the proposed control schemes, simulation studies on nonlinear MIMO dynamic system in the presence of high frequency bounded uncertainties and external disturbances are conducted and compared. Comparison of the results reveals the superiority of proposed RASMC over the traditional control schemes. RAMSC acts efficiently in disturbance rejection and keeping the system behavior in desirable tracking objectives, without the existence of unstable quasi-periodic solutions. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  18. The orificing of once-through boilers for gas-cooled reactors

    International Nuclear Information System (INIS)

    Collier, J.G.; Whitmarsh-Everiss, M.J.

    1986-01-01

    The boilers at Hinkley Point B, Hunterston B (which are built to a common design) and Hartlepool and Heysham (which are identical to each other although different from Hinkley B/Hunterston B) are discussed. Heysham II and Torness have boilers developed from the Hinkley B/Hunterston B design. The boiler design is explained and the problems encountered are presented. The study presented in this address highlights the potential sensitivity of the performance of once-through boilers to the following factors - the uniformity of the gas inlet temperature profile, the choice of the operating point on the boiler characteristic (preferably this should be where the performance of the unit is not too sensitive to the primary side temperature and flow distribution); this can be achieved by greater levels of orificing reducing the steady state gains, and the various plant operating states which introduce asymmetries into the boundary conditions for the boiler. A number of computer codes have been used to model boiler performance. Using these, a new design was proposed for boiler feed regulating orifices and these revised orifices were installed during outages on the two Heysham reactors in 1985. (U.K.)

  19. Uniqueness conditions in a hyperbolic model for oil recovery by steamdrive

    NARCIS (Netherlands)

    J. Bruining; C.J. van Duijn (Hans)

    1998-01-01

    textabstractIn this paper we study a one-dimensional model for oil recovery by steamdrive. This model consists of two parts: a (global) interface model and a (local) steam condensation/capillary diffusion model. In the interface model a steam condensation front (SCF) is present as an internal

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

    International Nuclear Information System (INIS)

    Christopher J. Zygarlicke; Donald P. McCollor; Steven A. Benson; Jay R. Gunderson

    2001-01-01

    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. Quality and generation rate of solid residues in the boiler of a waste-to-energy plant

    International Nuclear Information System (INIS)

    Allegrini, E.; Boldrin, A.; Jansson, S.; Lundtorp, K.; Fruergaard Astrup, T.

    2014-01-01

    Highlights: • Ash was sampled at 10 different points of the boiler of a waste-to-energy plant. • Samples were analysed for the chemical composition, PCDD/F and leaching behaviour. • Enrichment trends of elements were investigated in relation to boiler conditions. • No significant differences were found between boiler ash samples. - Abstract: The Danish waste management system relies significantly on waste-to-energy (WtE) plants. The ash produced at the energy recovery section (boiler ash) is classified as hazardous waste, and is commonly mixed with fly ash and air pollution control residues before disposal. In this study, a detailed characterization of boiler ash from a Danish grate-based mass burn type WtE was performed, to evaluate the potential for improving ash management. Samples were collected at 10 different points along the boiler's convective part, and analysed for grain size distribution, content of inorganic elements, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD and PCDF), and leaching of metals. For all samples, PCDD and PCDF levels were below regulatory limits, while high pH values and leaching of e.g. Cl were critical. No significant differences were found between boiler ash from individual sections of the boiler, in terms of total content and leaching, indicating that separate management of individual ash fractions may not provide significant benefits

  2. Quality and generation rate of solid residues in the boiler of a waste-to-energy plant

    Energy Technology Data Exchange (ETDEWEB)

    Allegrini, E., E-mail: elia@env.dtu.dk [Technical University of Denmark, Department of Environmental Engineering, Building 115, Lyngby 2800 (Denmark); Boldrin, A. [Technical University of Denmark, Department of Environmental Engineering, Building 115, Lyngby 2800 (Denmark); Jansson, S. [Umeå University, Department of Chemistry, Umeå SE-901 87 (Sweden); Lundtorp, K. [Babcock and Wilcox Vølund A/S, Göteborg (Sweden); Fruergaard Astrup, T. [Technical University of Denmark, Department of Environmental Engineering, Building 115, Lyngby 2800 (Denmark)

    2014-04-01

    Highlights: • Ash was sampled at 10 different points of the boiler of a waste-to-energy plant. • Samples were analysed for the chemical composition, PCDD/F and leaching behaviour. • Enrichment trends of elements were investigated in relation to boiler conditions. • No significant differences were found between boiler ash samples. - Abstract: The Danish waste management system relies significantly on waste-to-energy (WtE) plants. The ash produced at the energy recovery section (boiler ash) is classified as hazardous waste, and is commonly mixed with fly ash and air pollution control residues before disposal. In this study, a detailed characterization of boiler ash from a Danish grate-based mass burn type WtE was performed, to evaluate the potential for improving ash management. Samples were collected at 10 different points along the boiler's convective part, and analysed for grain size distribution, content of inorganic elements, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD and PCDF), and leaching of metals. For all samples, PCDD and PCDF levels were below regulatory limits, while high pH values and leaching of e.g. Cl were critical. No significant differences were found between boiler ash from individual sections of the boiler, in terms of total content and leaching, indicating that separate management of individual ash fractions may not provide significant benefits.

  3. Comparative study of operation of condensing and traditional boilers equipped with the ORC module for electricity generation

    Directory of Open Access Journals (Sweden)

    Mikielewicz Dariusz

    2017-01-01

    Full Text Available Condensing technology applied to boilers is to make full use of thermal energy contained in the fuel. That means that additionaly the heat from condensation of exhaust gases can be used for the purposes of heating the domestic hot water and to cover the demand for central heating. The study analyzed the operation of the “traditional” boiler equipped with the ORC module as the similar arrangement but with the condensing boiler. In the case of a conventional boiler there is noted a greater fuel consumption and the greater power generated than in the case of the unit with the condensing boiler. Postulated is the indicator in the form of a ratio of turbine power to the mass flow rate of fuel, which in turn gives a higher value for the condensing boiler, thus demonstrating that the operation of condensing boiler ORC module will be more economical. Perspective domestic micro CHP with ORC should be installed in boilers with recovery of heat from condensation from the exhaust gases.

  4. 46 CFR 52.25-20 - Exhaust gas boilers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Exhaust gas boilers. 52.25-20 Section 52.25-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS Other Boiler Types § 52.25-20 Exhaust gas boilers. Exhaust gas boilers with a maximum allowable working pressure...

  5. 46 CFR 63.25-1 - Small automatic auxiliary boilers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Small automatic auxiliary boilers. 63.25-1 Section 63.25... AUXILIARY BOILERS Requirements for Specific Types of Automatic Auxiliary Boilers § 63.25-1 Small automatic auxiliary boilers. Small automatic auxiliary boilers defined as having heat-input ratings of 400,000 Btu/hr...

  6. Personnel Recovery: Using Game Theory to Model Strategic Decision Making in the Contemporary Operating Environment

    National Research Council Canada - National Science Library

    Ecklund, Marshall V

    2005-01-01

    .... Thus, the central research question is as follows: Given a report of the physical location of an evader, is the military using the most rational decision-making model to offset the predictable nature of traditional recovery activities...

  7. Fluidized bed boiler feed system

    Science.gov (United States)

    Jones, Brian C.

    1981-01-01

    A fluidized bed boiler feed system for the combustion of pulverized coal. Coal is first screened to separate large from small particles. Large particles of coal are fed directly to the top of the fluidized bed while fine particles are first mixed with recycled char, preheated, and then fed into the interior of the fluidized bed to promote char burnout and to avoid elutriation and carryover.

  8. 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)

  9. 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)

  10. CHP Integrated with Burners for Packaged Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Castaldini, Carlo; Darby, Eric

    2013-09-30

    division of Sempra Energy. These match funds were provided via concurrent contracts and investments available via CMCE, Altex, and Leva Energy The project attained all its objectives and is considered a success. CMCE secured the support of GI&E from Italy to supply 100 kW Turbec T-100 microturbines for the project. One was purchased by the project’s subcontractor, Altex, and a second spare was purchased by CMCE under this project. The microturbines were then modified to convert from their original recuperated design to a simple cycle configuration. Replacement low-NOx silo combustors were designed and bench tested in order to achieve compliance with the California Air Resources Board (CARB) 2007 emission limits for NOx and CO when in CHP operation. The converted microturbine was then mated with a low NOx burner provided by Altex via an integration section that allowed flow control and heat recovery to minimize combustion blower requirements; manage burner turndown; and recover waste heat. A new fully integrated control system was designed and developed that allowed one-touch system operation in all three available modes of operation: (1) CHP with both microturbine and burner firing for boiler heat input greater than 2 MMBtu/hr; (2) burner head only (BHO) when the microturbine is under service; and (3) microturbine only when boiler heat input requirements fall below 2 MMBtu/hr. This capability resulted in a burner turndown performance of nearly 10/1, a key advantage for this technology over conventional low NOx burners. Key components were then assembled into a cabinet with additional support systems for generator cooling and fuel supply. System checkout and performance tests were performed in the laboratory. The assembled system and its support equipment were then shipped and installed at a host facility where final performance tests were conducted following efforts to secure fabrication, air, and operating permits. The installed power burner is now in commercial

  11. Dynamic Simulation of the Water-steam System in Once-through Boilers - Sub-critical Power Boiler Case -

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seongil; Choi, Sangmin [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2017-05-15

    The dynamics of a water-steam system in a once-through boiler was simulated based on the physics-based modeling approach, representing the system in response to large load change or scale disturbance simulations. The modeling considered the mass, energy conservation, and momentum equation in the water pipe and the focus was limited to the sub-critical pressure region. An evaporator tube modeling was validated against the reference data. A simplified boiler system consisting of economizer, evaporator, and superheater was constructed to match a 500 MW power boiler. The dynamic response of the system following a disturbance was discussed along with the quantitative response characteristics. The dynamic response of the boiler system was further evaluated by checking the case of an off-design point operation of the feedwater-to-fuel supply ratio. The results re-emphasized the significance of controlling the feedwater-to-fuel supply ratio and additional design requirements of the water-steam separator and spray attemperator.

  12. Dynamic Simulation of the Water-steam System in Once-through Boilers - Sub-critical Power Boiler Case -

    International Nuclear Information System (INIS)

    Kim, Seongil; Choi, Sangmin

    2017-01-01

    The dynamics of a water-steam system in a once-through boiler was simulated based on the physics-based modeling approach, representing the system in response to large load change or scale disturbance simulations. The modeling considered the mass, energy conservation, and momentum equation in the water pipe and the focus was limited to the sub-critical pressure region. An evaporator tube modeling was validated against the reference data. A simplified boiler system consisting of economizer, evaporator, and superheater was constructed to match a 500 MW power boiler. The dynamic response of the system following a disturbance was discussed along with the quantitative response characteristics. The dynamic response of the boiler system was further evaluated by checking the case of an off-design point operation of the feedwater-to-fuel supply ratio. The results re-emphasized the significance of controlling the feedwater-to-fuel supply ratio and additional design requirements of the water-steam separator and spray attemperator.

  13. Improvement of fire-tube boilers calculation methods by the numerical modeling of combustion processes and heat transfer in the combustion chamber

    Science.gov (United States)

    Komarov, I. I.; Rostova, D. M.; Vegera, A. N.

    2017-11-01

    This paper presents the results of study on determination of degree and nature of influence of operating conditions of burner units and flare geometric parameters on the heat transfer in a combustion chamber of the fire-tube boilers. Change in values of the outlet gas temperature, the radiant and convective specific heat flow rate with appropriate modification of an expansion angle and a flare length was determined using Ansys CFX software package. Difference between values of total heat flow and bulk temperature of gases at the flue tube outlet calculated using the known methods for thermal calculation and defined during the mathematical simulation was determined. Shortcomings of used calculation methods based on the results of a study conducted were identified and areas for their improvement were outlined.

  14. Boiler plants completed in record time

    International Nuclear Information System (INIS)

    Anon.

    2001-01-01

    Bubbling fluidised bed (BFB) combustion has steadily increased its share of the boiler market in recent years, particularly in the Nordic region, where it is particularly well-suited to handling the high moisture content biofuels produced and used by the forest products industry. Foster Wheeler is the world's leading supplier of fluidised bed combustion technology. Over 200 of the more than 300 fluidised bed boilers supplied by the company are circulating fluidised bed (CFB) designs, a market in which Foster Wheeler has more than a 40% share. Foster Wheeler Energia Oy supplied the Myllykoski project at Anjalankoski with a fluidised bed boiler, auxiliary steam boilers, and flue gas scrubber systems

  15. The Technology Introduction of Chain Boiler Energy Conservation Transformation

    Science.gov (United States)

    Li, Henan; Liu, Xiwen; Yuan, Hong; Lin, Jiadai; Zhang, Yu

    2017-12-01

    Introduced the present status of chain boiler efficiency is low, the system analysis of the chain boiler optimization and upgrading of technology, for the whole progress of chain boiler to provide some ideas and reference.

  16. Elevated temperature failures in boiler tubes - case studies

    International Nuclear Information System (INIS)

    Gowrisankar, I.; Bandyopadhyay, G.

    1989-01-01

    Metallurgical investigation of boiler tube failures enables identification of failure mechanisms and the underlying cause related to boiler conditions. Some case studies in short term overheating, prolonged overheating and low cycle fatigue failures in boiler tubes are discussed. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, William (Sandy) [SharpConsultant

    2011-12-01

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

  18. Multi-model assessment of stratospheric ozone return dates and ozone recovery in CCMVal-2 models

    Directory of Open Access Journals (Sweden)

    V. Eyring

    2010-10-01

    Full Text Available Projections of stratospheric ozone from a suite of chemistry-climate models (CCMs have been analyzed. In addition to a reference simulation where anthropogenic halogenated ozone depleting substances (ODSs and greenhouse gases (GHGs vary with time, sensitivity simulations with either ODS or GHG concentrations fixed at 1960 levels were performed to disaggregate the drivers of projected ozone changes. These simulations were also used to assess the two distinct milestones of ozone returning to historical values (ozone return dates and ozone no longer being influenced by ODSs (full ozone recovery. The date of ozone returning to historical values does not indicate complete recovery from ODSs in most cases, because GHG-induced changes accelerate or decelerate ozone changes in many regions. In the upper stratosphere where CO2-induced stratospheric cooling increases ozone, full ozone recovery is projected to not likely have occurred by 2100 even though ozone returns to its 1980 or even 1960 levels well before (~2025 and 2040, respectively. In contrast, in the tropical lower stratosphere ozone decreases continuously from 1960 to 2100 due to projected increases in tropical upwelling, while by around 2040 it is already very likely that full recovery from the effects of ODSs has occurred, although ODS concentrations are still elevated by this date. In the midlatitude lower stratosphere the evolution differs from that in the tropics, and rather than a steady decrease in ozone, first a decrease in ozone is simulated from 1960 to 2000, which is then followed by a steady increase through the 21st century. Ozone in the midlatitude lower stratosphere returns to 1980 levels by ~2045 in the Northern Hemisphere (NH and by ~2055 in the Southern Hemisphere (SH, and full ozone recovery is likely reached by 2100 in both hemispheres. Overall, in all regions except the tropical lower stratosphere, full ozone recovery from ODSs occurs significantly later than the

  19. Analysis of emission reduction strategies for power boilers in the US pulp and paper industry

    Data.gov (United States)

    U.S. Environmental Protection Agency — This paper first presents the background information for UISIS-PNP model by discussing different types of boilers installed throughout the pulp and paper sector, the...

  20. Mixed Higher Order Variational Model for Image Recovery

    Directory of Open Access Journals (Sweden)

    Pengfei Liu

    2014-01-01

    Full Text Available A novel mixed higher order regularizer involving the first and second degree image derivatives is proposed in this paper. Using spectral decomposition, we reformulate the new regularizer as a weighted L1-L2 mixed norm of image derivatives. Due to the equivalent formulation of the proposed regularizer, an efficient fast projected gradient algorithm combined with monotone fast iterative shrinkage thresholding, called, FPG-MFISTA, is designed to solve the resulting variational image recovery problems under majorization-minimization framework. Finally, we demonstrate the effectiveness of the proposed regularization scheme by the experimental comparisons with total variation (TV scheme, nonlocal TV scheme, and current second degree methods. Specifically, the proposed approach achieves better results than related state-of-the-art methods in terms of peak signal to ratio (PSNR and restoration quality.

  1. Mathematical models for the efficiency of flotation process for the recovery of north waziristan copper

    International Nuclear Information System (INIS)

    Ali, S.; Rahman, S.U.; Khan, M.M.

    2007-01-01

    Mathematical models were developed to give an insight into the effect of process variables, propylxanthae (X/sub 1/ g/ton), pH (X/sub 2/), sodium sulphide (X3 g/ton) and sodium cyanide (X/sub 4/ g/ton), on the recovery (YR) of copper. The optimum recovery (YR) 62.95%, was obtained at X/sub 4/=60g/ton. (author)

  2. EFFICIENCY IMPROVEMENT IN INDUSTRIAL BOILER BY FLUE GAS DUCT INSULATION

    OpenAIRE

    Sanjay H. Zala

    2017-01-01

    Now a days in industry major losses are find out so here we calculate these losses and find out efficiency of boiler. Boiler efficiency and energy losses from boiler are important parameter for any industry using boiler. In this work a detailed analysis was carried out for boiler at Anish Chemicals Bhavnagar. It is a combined water and fire tube boiler using biomass coal as fuel. Boiler efficiency calculated by direct method is in range of (78.5% to 81.6%). Major losses from boiler are heat ...

  3. An Integrated Recovery-oriented Model (IRM) for mental health services: evolution and challenges.

    Science.gov (United States)

    Frost, Barry G; Tirupati, Srinivasan; Johnston, Suzanne; Turrell, Megan; Lewin, Terry J; Sly, Ketrina A; Conrad, Agatha M

    2017-01-17

    Over past decades, improvements in longer-term clinical and personal outcomes for individuals experiencing serious mental illness (SMI) have been moderate, although recovery has clearly been shown to be possible. Recovery experiences are inherently personal, and recovery can be complex and non-linear; however, there are a broad range of potential recovery contexts and contributors, both non-professional and professional. Ongoing refinement of recovery-oriented models for mental health (MH) services needs to be fostered. This descriptive paper outlines a service-wide Integrated Recovery-oriented Model (IRM) for MH services, designed to enhance personally valued health, wellbeing and social inclusion outcomes by increasing access to evidenced-based psychosocial interventions (EBIs) within a service context that supports recovery as both a process and an outcome. Evolution of the IRM is characterised as a series of five broad challenges, which draw together: relevant recovery perspectives; overall service delivery frameworks; psychiatric and psychosocial rehabilitation approaches and literature; our own clinical and service delivery experience; and implementation, evaluation and review strategies. The model revolves around the person's changing recovery needs, focusing on underlying processes and the service frameworks to support and reinforce hope as a primary catalyst for symptomatic and functional recovery. Within the IRM, clinical rehabilitation (CR) practices, processes and partnerships facilitate access to psychosocial EBIs to promote hope, recovery, self-agency and social inclusion. Core IRM components are detailed (remediation of functioning; collaborative restoration of skills and competencies; and active community reconnection), together with associated phases, processes, evaluation strategies, and an illustrative IRM scenario. The achievement of these goals requires ongoing collaboration with community organisations. Improved outcomes are achievable for

  4. Applied Gaussian Process in Optimizing Unburned Carbon Content in Fly Ash for Boiler Combustion

    Directory of Open Access Journals (Sweden)

    Chunlin Wang

    2017-01-01

    Full Text Available Recently, Gaussian Process (GP has attracted generous attention from industry. This article focuses on the application of coal fired boiler combustion and uses GP to design a strategy for reducing Unburned Carbon Content in Fly Ash (UCC-FA which is the most important indicator of boiler combustion efficiency. With getting rid of the complicated physical mechanisms, building a data-driven model as GP is an effective way for the proposed issue. Firstly, GP is used to model the relationship between the UCC-FA and boiler combustion operation parameters. The hyperparameters of GP model are optimized via Genetic Algorithm (GA. Then, served as the objective of another GA framework, the predicted UCC-FA from GP model is utilized in searching the optimal operation plan for the boiler combustion. Based on 670 sets of real data from a high capacity tangentially fired boiler, two GP models with 21 and 13 inputs, respectively, are developed. In the experimental results, the model with 21 inputs provides better prediction performance than that of the other. Choosing the results from 21-input model, the UCC-FA decreases from 2.7% to 1.7% via optimizing some of the operational parameters, which is a reasonable achievement for the boiler combustion.

  5. FY 2000 report on the potential survey of the environmental friendly type coal utilization system. Survey for digging up items for the model project on spread type circulating fluid bed boilers in China; 2000 nendo chosa hokokusho. Kankyo chowagata sekitan riyo system kanosei chosa. Chugoku ni okeru fukyugata junkan ryudo yukaboira setsubi model jigyo no anken hakkutsu chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-09-01

    For the purpose of spreading/promoting circulating fluidized bed boilers in China, survey was conducted on the confirmation of effectiveness of implementation of the model project on spread type circulating fluidized bed boilers and the appropriateness of the sites proposed for implementation. As to the model of spread type 35t/h-CFB boilers, local products are more integrated into it, taking cost reduction of equipment and secure performance/quality into consideration, and the wider-ranging technical guidance/transfer are conducted also in design/production. In China, where environmental regulations are not strict, and there are many restrictions on funds, the size of the initial investment is an important element for selection of type. Further, the market is very big, about 200 units/year. It is highly possible to realize the competitive cost level by the quantity production effect by increasing local production. Two companies, Southeast Electrochemical Co. and Fujian Prime Pharmaceutical Group Co., which were proposed as sites are financially good and are achieving substantial results. Both companies are located in the urban area, and therefore, environmental measures should urgently be taken, and PR activities for spread are highly effective. It was confirmed that the companies were fully appropriate as sites proposed for the spread type model project. (NEDO)

  6. Recovery as a model of care? Insights from an Australian case study.

    Science.gov (United States)

    Hungerford, Catherine

    2014-03-01

    The terms "model of health care," "service model." and "nursing model of practice" are often used interchangeably in practice, policy, and research, despite differences in definitions. This article considers these terms in the context of consumer-centred recovery and its implementation into a publicly-funded health service organization in Australia. Findings of a case study analysis are used to inform the discussion, which considers the diverse models of health care employed by health professionals; together with the implications for organizations worldwide that are responsible for operationalizing recovery approaches to health care. As part of the discussion, it is suggested that the advent of recovery-oriented services, rather than recovery models of health care, presents challenges for the evaluation of the outcomes of these services. At the same time, this situation provides opportunities for mental health nurses to lead the way, by developing rigorous models of practice that support consumers who have acute, chronic, or severe mental illness on their recovery journey; and generate positive, measureable outcomes.

  7. Predicting recovery of cognitive function soon after stroke: differential modeling of logarithmic and linear regression.

    Science.gov (United States)

    Suzuki, Makoto; Sugimura, Yuko; Yamada, Sumio; Omori, Yoshitsugu; Miyamoto, Masaaki; Yamamoto, Jun-ichi

    2013-01-01

    Cognitive disorders in the acute stage of stroke are common and are important independent predictors of adverse outcome in the long term. Despite the impact of cognitive disorders on both patients and their families, it is still difficult to predict the extent or duration of cognitive impairments. The objective of the present study was, therefore, to provide data on predicting the recovery of cognitive function soon after stroke by differential modeling with logarithmic and linear regression. This study included two rounds of data collection comprising 57 stroke patients enrolled in the first round for the purpose of identifying the time course of cognitive recovery in the early-phase group data, and 43 stroke patients in the second round for the purpose of ensuring that the correlation of the early-phase group data applied to the prediction of each individual's degree of cognitive recovery. In the first round, Mini-Mental State Examination (MMSE) scores were assessed 3 times during hospitalization, and the scores were regressed on the logarithm and linear of time. In the second round, calculations of MMSE scores were made for the first two scoring times after admission to tailor the structures of logarithmic and linear regression formulae to fit an individual's degree of functional recovery. The time course of early-phase recovery for cognitive functions resembled both logarithmic and linear functions. However, MMSE scores sampled at two baseline points based on logarithmic regression modeling could estimate prediction of cognitive recovery more accurately than could linear regression modeling (logarithmic modeling, R(2) = 0.676, PLogarithmic modeling based on MMSE scores could accurately predict the recovery of cognitive function soon after the occurrence of stroke. This logarithmic modeling with mathematical procedures is simple enough to be adopted in daily clinical practice.

  8. Fiscal 2000 achievement report. Model project for international energy consumption efficiency improvement (Model project for improvement of boiler and turbine efficiency); 2000 nendo seika hokoku. Kokusai energy shohi koritsuka tou model jigyo (Boira tabin koritsu kojo model jigyo)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-12-01

    A project was implemented for Japan to transfer its energy conservation technologies for helping Indonesia conserve energy and reduce CO2 emissions, which occurred at Muara Karang Thermal Power Plant of an Indonesian power company named PT PJB. Items to be introduced are condenser tubes (material change from cupro-nickel to titanium), ball cleaning equipment, turbine gland seal improvement, air preheater improvement, thermal efficiency management system, and so forth. In this fiscal year, turbine gland seals and air preheater elements were manufactured, and the thermal efficiency management system was designed. As an dissemination activity, 10 engineers were invited to Japan from the Indonesian Ministry of Energy and Mineral Resources, PT PLN, and PT PJB. They attended a training program lasting approximately two weeks, which included study tours to the factories actually building the equipment to be introduced and field/classroom training/education on thermal efficiency management and others. The engineers actively performed their boiler improvement work back in Indonesia. (NEDO)

  9. Investigation of transient behaviour of combi boiler type appliances for domestic hot water

    International Nuclear Information System (INIS)

    Atmaca, Ayşe Uğurcan; Erek, Aytunç; Altay, Hürrem Murat

    2015-01-01

    Combi boiler type appliances heating both space and water demanded for use and consuming natural gas as the energy source are one of the most common branches of the household goods. This study touches mainly on two types of combi boiler concepts to investigate only domestic hot water (DHW) heating function since highly efficient condensing appliances have been manufactured in terms of space heating. First concept has the normal working configuration of the heat exchangers of a standard combi boiler; whereas, the second has the opposite operation order of the heat exchangers. 1D transient energy equations have been constructed with the help of the laws of thermodynamics in order to model the heat exchangers in a standard combi boiler. After obtaining a general mathematical model for the standard combi boiler, the energy equations have been discretised with finite difference scheme, and solved numerically in Matlab ® . Subsequently, numerical results are validated experimentally in different working modes of a standard appliance. As the last step, similar results are obtained for the second proposed concept using the related equations of the standard combi model to compare both concepts on a numerical basis. - Highlights: • 1D theoretical model of a combi boiler was constructed and verified experimentally. • Preliminary estimations will be obtained from the model about the laboratory tests. • Number of the laboratory tests will be decreased thanks to the theoretical model. • The model was used to compare the transient behaviour of two kinds of combi boilers. • The second combi boiler alternative to standard one has a higher comfort potential

  10. Possibility analysis of combustion of torrefied biomass in 140 t/h PC boiler

    Directory of Open Access Journals (Sweden)

    Jagodzińska Katarzyna

    2016-01-01

    Full Text Available The study attempts to evaluate the impact of combustion of torrefied willow (Latin: Salix viminalis and palm kernel shell (Latin: Elaeis guineensis on the heat exchange in a 140 t/h PC boiler through an analysis of 6 cases for different boiler loads (60 %, 75 % and 100 % and a comparison with coal combustion. The analysis is premised on a 0-dimensional model based on the method presented in [15, 16, 17] and long-standing experimental measurements. Inter alia, the following results are presented: the temperature distribution of flue gases and the working medium (water/steam in characteristic points of the boiler as well as heat transfer coefficients for each element thereof. The temperature distribution of both fluids and the heat transfer coefficients are similar for all analysed fuels for each boiler load. However, the flue gas temperature at the outlet is higher in the case of torrefied biomass combustion. Due to that, there is an increase in the stack loss, which involves a decrease in the boiler efficiency. The conclusion is that torrefied biomass combustion is possible in a PC boiler without the need to change the boiler construction. However, it would be less effective than coal combustion.

  11. Enviro-exergy sustainability analysis of boiler evolution in district energy system

    International Nuclear Information System (INIS)

    Compton, M.; Rezaie, B.

    2017-01-01

    Investigations into energy resources are important from the point of energy sustainability. The principal objective of this study is to investigate the evolution of the operating boilers at the University of Idaho (UI) district energy plant through an exergy analysis. The biomass boiler uses western red cedar chips from nearby lumber mills and provides 95% of the steam requirements of the main campus of UI in Moscow, ID, USA. Thermodynamic analysis reveals a thermal efficiency of 76% and an exergy efficiency of 24% for the biomass boiler. A combustion model is developed to determine the primary emissions products of both the bone dry wood chips and natural gas fuels. CO 2 comprises 26% of the bone dry biomass emissions and 8% of the natural gas emissions products. Testing results of the biomass boiler exhaust stack show CO 2 emissions of 14% when an average moisture content of 33% is accounted for. An overview of the evolution of the energy plant is discussed, showing the generational differences in each boiler. By using a biomass fuel source, the cost per 1000 kg of steam produced is on average 63% lower than using natural gas, resulting in savings of over $1 million annually. - Highlights: • Exergy efficiency comparison of biomass and natural gas boilers. • Moisture content in biomass reduces average heating value and exergy efficiency. • Local sustainable energy sources can result in economic savings over fossil fuels. • Older boilers can have comparable efficiencies with newer ones after improvements.

  12. Modeling Reef Fish Biomass, Recovery Potential, and Management Priorities in the Western Indian Ocean.

    Science.gov (United States)

    McClanahan, Timothy R; Maina, Joseph M; Graham, Nicholas A J; Jones, Kendall R

    2016-01-01

    Fish biomass is a primary driver of coral reef ecosystem services and has high sensitivity to human disturbances, particularly fishing. Estimates of fish biomass, their spatial distribution, and recovery potential are important for evaluating reef status and crucial for setting management targets. Here we modeled fish biomass estimates across all reefs of the western Indian Ocean using key variables that predicted the empirical data collected from 337 sites. These variables were used to create biomass and recovery time maps to prioritize spatially explicit conservation actions. The resultant fish biomass map showed high variability ranging from ~15 to 2900 kg/ha, primarily driven by human populations, distance to markets, and fisheries management restrictions. Lastly, we assembled data based on the age of fisheries closures and showed that biomass takes ~ 25 years to recover to typical equilibrium values of ~1200 kg/ha. The recovery times to biomass levels for sustainable fishing yields, maximum diversity, and ecosystem stability or conservation targets once fishing is suspended was modeled to estimate temporal costs of restrictions. The mean time to recovery for the whole region to the conservation target was 8.1(± 3SD) years, while recovery to sustainable fishing thresholds was between 0.5 and 4 years, but with high spatial variation. Recovery prioritization scenario models included one where local governance prioritized recovery of degraded reefs and two that prioritized minimizing recovery time, where countries either operated independently or collaborated. The regional collaboration scenario selected remote areas for conservation with uneven national responsibilities and spatial coverage, which could undermine collaboration. There is the potential to achieve sustainable fisheries within a decade by promoting these pathways according to their social-ecological suitability.

  13. Economic evaluation of a coal fired boiler

    International Nuclear Information System (INIS)

    Briem, J.J.

    1983-01-01

    This paper provides basic information on boiler economics which will assist steam users in analyzing the feasibility of using coal to generate steam - in either new or existing facilities. The information presented covers boilers ranging in size from 10,000 to 100,000 pounds per hour steaming capacity

  14. 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 COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.555 Propulsion boilers. The master or person in charge and the engineer in charge shall...

  15. 29 CFR 1915.162 - Ship's boilers.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Ship's boilers. 1915.162 Section 1915.162 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT Ship's Machinery and Piping Systems § 1915.162 Ship's boilers. (a) Before...

  16. Increased combustion stability in modulating biomass boilers for district heating systems

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, Gunnar; Hermansson, Roger (eds.) [Lulea Univ. of Technology (Sweden)

    2002-09-01

    One of the problems in small district heating systems is the large load variation that must be handled by the system. If the boiler is designed to cover the needs during the coldest day in winter time in northern Europe it would have to run at loads as low as 10% of full load during summer time, when heat is needed only for tap water production. Load variations in small networks are quite fast and earlier investigations have shown that existing biomass boilers give rise to large amounts of harmful emissions at fast load variations and at low loads. The problem has been addressed in different ways: Three new boiler concepts have been realized and tested: A prototype of a 500 kW boiler with partitioned primary combustion chamber and supplied with a water heat store. A 10 kW bench scale combustor and a 500 kW prototype boiler based on pulsating combustion. Bench scale boilers to test the influence from applied sound on emissions and a 150 kW prototype boiler with a two-stage secondary vortex combustion chamber. Development of control and regulating equipment: Glow Guard, a control system using infra-red sensors to detect glowing char on the grate, has been constructed and tested. A fast prediction model that can be used in control systems has been developed. Simulation of the combustion process: Code to simulate pyrolysis/gasification of fuel on the grate has been developed. Combustion of the gas phase inside the combustion chamber has been simulated. The two models have been combined to describe the combustion process inside the primary chamber of a prototype boiler. A fast simulation code based on statistical methods that can predict the environmental performance of boilers has been developed. One of the boiler concepts matches the desired load span from 10 to 100% of full load with emissions far below the set limits for CO and THC and close to the set limits for NO{sub x}. The other boilers had a bit more narrow load range, one with very low emissions except for NO

  17. Recovery of time-dependent volatility in option pricing model

    Science.gov (United States)

    Deng, Zui-Cha; Hon, Y. C.; Isakov, V.

    2016-11-01

    In this paper we investigate an inverse problem of determining the time-dependent volatility from observed market prices of options with different strikes. Due to the non linearity and sparsity of observations, an analytical solution to the problem is generally not available. Numerical approximation is also difficult to obtain using most of the existing numerical algorithms. Based on our recent theoretical results, we apply the linearisation technique to convert the problem into an inverse source problem from which recovery of the unknown volatility function can be achieved. Two kinds of strategies, namely, the integral equation method and the Landweber iterations, are adopted to obtain the stable numerical solution to the inverse problem. Both theoretical analysis and numerical examples confirm that the proposed approaches are effective. The work described in this paper was partially supported by a grant from the Research Grant Council of the Hong Kong Special Administrative Region (Project No. CityU 101112) and grants from the NNSF of China (Nos. 11261029, 11461039), and NSF grants DMS 10-08902 and 15-14886 and by Emylou Keith and Betty Dutcher Distinguished Professorship at the Wichita State University (USA).

  18. Models for embrittlement recovery due to annealing of reactor pressure vessel steels

    International Nuclear Information System (INIS)

    Eason, E.D.; Wright, J.E.; Nelson, E.E.; Odette, G.R.; Mader, E.V.

    1995-05-01

    The reactor pressure vessel (RPV) surrounding the core of a commercial nuclear power plant is subject to embrittlement due to exposure to high energy neutrons. The effects of irradiation embrittlement can be reduced by thermal annealing at temperatures higher than the normal operating conditions. However, a means of quantitatively assessing the effectiveness of annealing for embrittlement recovery is needed. The objective of this work was to analyze the pertinent data on this issue and develop quantitative models for estimating the recovery in 30 ft-lb (41 J) Charpy transition temperature and Charpy upper shelf energy due to annealing. Data were gathered from the Test Reactor Embrittlement Data Base and from various annealing reports. An analysis data base was developed, reviewed for completeness and accuracy, and documented as part of this work. Independent variables considered in the analysis included material chemistries, annealing time and temperature, irradiation time and temperature, fluence, and flux. To identify important variables and functional forms for predicting embrittlement recovery, advanced statistical techniques, including pattern recognition and transformation analysis, were applied together with current understanding of the mechanisms governing embrittlement and recovery. Models were calibrated using multivariable surface-fitting techniques. Several iterations of model calibration, evaluation with respect to mechanistic and statistical considerations, and comparison with the trends in hardness data produced correlation models for estimating Charpy upper shelf energy and transition temperature after irradiation and annealing. This work provides a clear demonstration that (1) microhardness recovery is generally a very good surrogate for shift recovery, and (2) there is a high level of consistency between the observed annealing trends and fundamental models of embrittlement and recovery processes

  19. Numerical investigation towards a HiTAC condition in a 9MW heavy fuel-oil boiler

    NARCIS (Netherlands)

    Zhu, Shanglong; Venneker, Bart; Roekaerts, Dirk; Pozarlik, Artur; van der Meer, Theo

    2013-01-01

    In this study, several conditions in a 9 MW heavy fuel-oil boiler were numerically studied in order to get a better understanding of the application of HiTAC in such a boiler. Simulations were done with an Euler- Lagrange approach. The Eddy Dissipation model was used for combustion. Simulation

  20. Chemical cleaning of AGR boilers

    International Nuclear Information System (INIS)

    Moore, S.V.; Moore, W.; Rantell, A.

    1978-01-01

    AGR boilers are likely to require post service chemical cleaning to remove accumulated oxides at intervals of 15 - 35 kh. The need to clean will be based on an assessment of such factors as the development of flow imbalances through parallel tubes induced by the formation of rough oxide surfaces, an increasing risk of localised corrosion as the growth of porous oxides proceeds and the risk of tube blockage caused by the exfoliation of steam-grown oxides. The study has shown what heterogeneous multilayer oxides possessing a range of physical and chemical properties form on the alloy steels. They include porous and compact magnetites, chromium spinels and sesquioxide. Ammoniated citric acid has been shown to remove deposited and water-grown magnetites from the carbon and alloy steels but will not necessarily remove the substituted spinels grown on the alloy steels or the potentially spalling steam-grown magnetite on the A1SI 316 superheater. Citric acid supplemented with the reducing agent glyoxal completely removes all oxides from the boiler except the protective inner spinel formed on the 316. Removal of the spinels and compact magnetites occurs more by undercutting and physical detachment than by the dissolution. (author)

  1. Modeling Donnan Dialysis Separation for Carboxylic Anion Recovery

    DEFF Research Database (Denmark)

    Prado Rubio, Oscar Andres; Møllerhøj, Martin; Jørgensen, Sten Bay

    2010-01-01

    layers and membranes. Donnan equilibrium, flux continuity of the transported ions, the electroneutrality condition and Faraday's law are employed to describe the electrical potential and concentration discontinuities at the interfaces. The Nernst-Planck equation is used to model the ion transport though...... boundary layers and membranes. The model consists of a system of partial differential equations that are solved numerically. The aim of this paper is to corroborate this general model for several monoprotic carboxylic acids reported in the literature. The model reproduces satisfactorily experimental fluxes...

  2. Thermoelectric Generators for Automotive Waste Heat Recovery Systems Part I: Numerical Modeling and Baseline Model Analysis

    Science.gov (United States)

    Kumar, Sumeet; Heister, Stephen D.; Xu, Xianfan; Salvador, James R.; Meisner, Gregory P.

    2013-04-01

    A numerical model has been developed to simulate coupled thermal and electrical energy transfer processes in a thermoelectric generator (TEG) designed for automotive waste heat recovery systems. This model is capable of computing the overall heat transferred, the electrical power output, and the associated pressure drop for given inlet conditions of the exhaust gas and the available TEG volume. Multiple-filled skutterudites and conventional bismuth telluride are considered for thermoelectric modules (TEMs) for conversion of waste heat from exhaust into usable electrical power. Heat transfer between the hot exhaust gas and the hot side of the TEMs is enhanced with the use of a plate-fin heat exchanger integrated within the TEG and using liquid coolant on the cold side. The TEG is discretized along the exhaust flow direction using a finite-volume method. Each control volume is modeled as a thermal resistance network which consists of integrated submodels including a heat exchanger and a thermoelectric device. The pressure drop along the TEG is calculated using standard pressure loss correlations and viscous drag models. The model is validated to preserve global energy balances and is applied to analyze a prototype TEG with data provided by General Motors. Detailed results are provided for local and global heat transfer and electric power generation. In the companion paper, the model is then applied to consider various TEG topologies using skutterudite and bismuth telluride TEMs.

  3. DEFINING RECOVERY GOALS AND STRATEGIES FOR ENDANGERED SPECIES USING SPATIALLY-EXPLICIT POPULATION MODELS

    Science.gov (United States)

    We used a spatially explicit population model of wolves (Canis lupus) to propose a framework for defining rangewide recovery priorities and finer-scale strategies for regional reintroductions. The model predicts that Yellowstone and central Idaho, where wolves have recently been ...

  4. Heat exchanger modeling and identification for control of waste heat recovery systems in diesel engines

    NARCIS (Netherlands)

    Feru, E.; Willems, F.P.T.; Rojer, C.; Jager, B. de; Steinbuch, M.

    2013-01-01

    To meet future CO2 emission targets, Waste Heat Recovery systems have recently attracted much attention for automotive applications, especially for long haul trucks. This paper focuses on the development of a dynamic counter-flow heat exchanger model for control purposes. The model captures the

  5. A modelling assessment of acidification and recovery of European surface waters

    Science.gov (United States)

    Jenkins, A.; Camarero, L.; Cosby, B. J.; Ferrier, R. C.; Forsius, M.; Helliwell, R. C.; Kopácek, J.; Majer, V.; Moldan, F.; Posch, M.; Rogora, M.; Schöpp, W.; Wright, R. F.

    The increase in emission of sulphur oxides and nitrogen (both oxidised and reduced forms) since the mid-1800s caused a severe decline in pH and ANC in acid-sensitive surface waters across Europe. Since c.1980, these emissions have declined and trends towards recovery from acidification have been widely observed in time-series of water chemistry data. In this paper, the MAGIC model was applied to 10 regions (the SMART model to one) in Europe to address the question of future recovery under the most recently agreed emission protocols (the 1999 Gothenburg Protocol). The models were calibrated using best available data and driven using S and N deposition sequences for Europe derived from EMEP data. The wide extent and the severity of water acidification in 1980 in many regions were illustrated by model simulations which showed significant deterioration in ANC away from the pre-acidification conditions. The simulations also captured the recovery to 2000 in response to the existing emission reductions. Predictions to 2016 indicated further significant recovery towards pre-acidification chemistry in all regions except Central England (S Pennines), S Alps, S Norway and S Sweden. In these areas it is clear that further emission reductions will be required and that the recovery of surface waters will take several decades as soils slowly replenish their depleted base cation pools. Chemical recovery may not, however, ensure biological recovery and further reductions may also be required to enable these waters to achieve the "good ecological status" as required by the EU Water Framework Directive.

  6. Assessing the impact of primary measures for NOx reduction on the thermal power plant steam boiler

    International Nuclear Information System (INIS)

    Stupar, Goran; Tucaković, Dragan; Živanović, Titoslav; Belošević, Srdjan

    2015-01-01

    The European normatives prescribe content of 200 mg/Nm 3 NO x for pulverized coal combusting power plants. In order to reduce content of NO x in Serbian thermal power plant (TPP) 'Kostolac B' it's necessary to implement particular measures until 2016. The mathematical model of lignite combustion in the steam boiler furnace is defined and applied to analyze the possibility of implementing certain primary measures for reducing nitrogen oxides and their effects on the steam boiler operation. This model includes processes in the coal-fired furnace and defines radiating reactive two-phase turbulent flow. The model of turbulent flow also contains sub-model of fuel and thermal NO x formation and destruction. This complex mathematical model is related to thermal and aerodynamic calculations of the steam boiler within a unified calculation system in order to analyze the steam boiler overall work. This system provides calculations with a number of influential parameters. The steam boiler calculations for unit 1 (350 MWe) of TPP 'Kostolac B' are implemented for existing and modified combustion system in order to achieve effective, reliable and ecological facility work. The paper presents the influence analysis of large number of parameters on the steam boiler operation with an accepted concept of primary measures. Presented system of calculations is verified against measurements in TPP 'Kostolac B'. - Highlights: • Modern steam boilers need to operate according to ecological standards. • Possibility of applying some of the primary measures of NO x reduction. • Conventional calculations have no possibility to estimate sub-stoichiometric combustion. • Develop a new method of connecting the calculations. • Analysis shows the most favorable operation boiler regime (efficiency and ecology)

  7. Simulation of pulverized coal fired boiler: reaction chamber

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, C.P.; Lansarin, M.A.; Secchi, A.R.; Mendes, T.F. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Dept. de Engenharia Quimica. Grupo de Modelagem, Simulacao, Controle e Otimizacao de Processos)]. E-mail: {cperdomo, marla, arge, talita}@enq.ufrgs.br

    2005-06-15

    This work is part of a joint project to built a computational tool for power plant simulation, dealing specifically with the reaction chamber (place of the boiler where the fuel is burned). In order to describe the conversion of chemical energy to thermal energy, an one dimensional pseudo-homogeneous mathematical model, with variable physical properties, and based on mass and energy balances, was developed. The equations were implemented in the gPROMS simulator and the model parameters were estimated using the module gEST of this software, with experimental data from a large-scale coal-fired utility boiler and kinetic data from the open literature. The results showed that the model predicts the composition of the outlet combustion gas satisfactorily. (author)

  8. Constitutive model of creep in polycrystalline halite based on workhardening and recovery

    International Nuclear Information System (INIS)

    Munson, D.E.

    1993-01-01

    A multimechanism constitutive model of creep has been developed which incorporates the workhardening and recovery transient creep behavior. This model has been applied to the creep of polycrystalline halite. The specific application of the model is in the calculation of the closure of underground rooms in layered salt deposits. Through the use of finite element calculations, this model, with appropriate laboratory material parameters and a Tresca flow potential, has predicted the measured closure of a number of large in situ experimental rooms

  9. Quality and generation rate of solid residues in the boiler of a waste-to-energy plant

    DEFF Research Database (Denmark)

    Allegrini, Elisa; Boldrin, Alessio; Jansson, S.

    2014-01-01

    The Danish waste management system relies significantly on waste-to-energy (WtE) plants. The ash produced at the energy recovery section (boiler ash) is classified as hazardous waste, and is commonly mixed with fly ash and air pollution control residues before disposal. In this study, a detailed...... characterization of boiler ash from a Danish grate-based mass burn type WtE was performed, to evaluate the potential for improving ash management. Samples were collected at 10 different points along the boiler's convective part, and analysed for grain size distribution, content of inorganic elements......, polychlorinated dibenzo-. p-dioxins and dibenzofurans (PCDD and PCDF), and leaching of metals. For all samples, PCDD and PCDF levels were below regulatory limits, while high pH values and leaching of e.g. Cl were critical. No significant differences were found between boiler ash from individual sections...

  10. Modelling of the intragranular back-stress and recovery in FCC single crystals and polycrystals

    International Nuclear Information System (INIS)

    Sauzay, M.

    2003-01-01

    High temperature mechanical tests including recovery times on FCC metals or alloys involve at least two mechanisms. First, the formation of a two phase dislocation microstructure (cells, walls/channels... ) induces intragranular back-stress and hardening. Second, if the recovery time and the temperature are large enough, the previously formed dislocation microstructure can disappear, even if no remote stress is applied. Simple models of these two mechanisms are proposed. They are based on TEM observations and are validated comparing with several measurements from the literature. These models do not use arty fitted parameter and could help to predict the macroscopic behavior during creep-fatigue tests. (author)

  11. Modelling of the intragranular back-stress and recovery in FCC single crystals and polycrystals

    Energy Technology Data Exchange (ETDEWEB)

    Sauzay, M

    2003-07-01

    High temperature mechanical tests including recovery times on FCC metals or alloys involve at least two mechanisms. First, the formation of a two phase dislocation microstructure (cells, walls/channels... ) induces intragranular back-stress and hardening. Second, if the recovery time and the temperature are large enough, the previously formed dislocation microstructure can disappear, even if no remote stress is applied. Simple models of these two mechanisms are proposed. They are based on TEM observations and are validated comparing with several measurements from the literature. These models do not use arty fitted parameter and could help to predict the macroscopic behavior during creep-fatigue tests. (author)

  12. Determination of the Nonlinearity Parameter in the TNM Model of Structural Recovery

    Science.gov (United States)

    Bari, Rozana; Simon, Sindee

    Structural recovery of non-equilibrium glassy materials takes place by evolution of volume and enthalpy as the glass attempts to reach to equilibrium. Structural recovery is nonlinear, nonexponential, and depends on thermal history and the process can be described by phenomenological models of structural recovery, such as the Tool-Narayanaswamy-Moynihan (TNM) and the Kovacs-Aklonis-Hutchinson-Ramos (KAHR) models. The goal of the present work is to analyze methods to determine the nonlinearity parameter x and activation energy Δh/R. The methods to determine x includes the inflectional analysis, time-temperature superposition, and two-step temperature jump methods. The activation energy Δh/R can also be obtained by the first two methods. The TNM model is used to simulate structural recovery data, which are then used to test the accuracy of the methods to determine x and Δh/R, with a particular interest in data obtained after cooling at high rates as can be obtained in the Flash DSC. The nonlinearity parameter x by the inflectional analysis and two-step temperature methods are accurate for exponential recovery. However, for real systems with nonexponential relaxation, methods to determine x are not reliable. The activation energy is well estimated by both the time-temperature superposition and inflectional analysis methods, with the former being slightly better.

  13. Modelación energética y operacional del sistema de agua de alimentar caldera de una central termoeléctrica; Modeling energetic and operational of the boiler feed water system of a power plant

    Directory of Open Access Journals (Sweden)

    Ernesto Miguel Solís Alemán

    2015-09-01

    Full Text Available Se propone un modelo combinado basado en la implementación paralela de dos aproximadores funcionales, utilizando una red neuronal del tipo (MLP y una regresión estadística, para la obtención de las características energéticas y de operación actual del Sistema de Agua de Alimentar Caldera (SAAC en una Central Termoeléctrica (CTE, en la cual se regula el flujo de agua a la caldera por variación de velocidad. La respuesta del modelo combinado se obtiene a partir de la suma ponderada de cada aproximador funcional. Dicho modelo es utilizado para relacionar el consumo de corriente y la posición del variador de velocidad, en función de la presión de descarga y el flujo entregado por cada bomba del SAAC. Para el ajuste de los modelos se utilizan mediciones almacenadas en el archivo histórico del sistema SCADA, donde se aplica un método de procesamiento de datos para eliminar ruidos que pueden afectar el ajuste de los modelos propuestos.Is proposed a combined model based on the parallel implementation of two functional approximators, using a neural network of the type (MLP and a statistical regression to obtain the actual energetic and operation characteristics of the Boiler Feed Water System (BFWS in a Power Plant, in which the water flow to the boiler is controlled by variation speed. The response of the combined model is obtained from the weighted sum of each functional approximator. This model is used to relate the current consumption and the position of the speed variator, in function of the discharge pressure and flow delivered by each pump of the BFWS. For the fit of the models is used save measurements of the historical file of the SCADA system, where is applied a data processing method to eliminating noise that can affect the fit of the models proposed.

  14. Enthalpy recovery in glassy materials: Heterogeneous versus homogenous models

    Science.gov (United States)

    Mazinani, Shobeir K. S.; Richert, Ranko

    2012-05-01

    Models of enthalpy relaxations of glasses are the basis for understanding physical aging, scanning calorimetry, and other phenomena that involve non-equilibrium and non-linear dynamics. We compare models in terms of the nature of the relaxation dynamics, heterogeneous versus homogeneous, with focus on the Kovacs-Aklonis-Hutchinson-Ramos (KAHR) and the Tool-Narayanaswamy-Moynihan (TNM) approaches. Of particular interest is identifying the situations for which experimental data are capable of discriminating the heterogeneous from the homogeneous scenario. The ad hoc assumption of a single fictive temperature, Tf, is common to many models, including KAHR and TNM. It is shown that only for such single-Tf models, enthalpy relaxation of a glass is a two-point correlation function in reduced time, implying that experimental results are not decisive regarding the underlying nature of the dynamics of enthalpy relaxation. We also find that the restriction of the common TNM model to a Kohlrausch-Williams-Watts type relaxation pattern limits the applicability of this approach, as the particular choice regarding the distribution of relaxation times is a more critical factor compared with isothermal relaxation experiments. As a result, significant improvements in fitting calorimetry data can be achieved with subtle adjustments in the underlying relaxation time distribution.

  15. 46 CFR 61.05-15 - Boiler mountings and attachments.

    Science.gov (United States)

    2010-10-01

    ... 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. (a....05-10. (b) Each stud or bolt for each boiler mounting that paragraph (c) of this section requires to...

  16. 46 CFR 63.25-7 - Exhaust gas boilers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Exhaust gas boilers. 63.25-7 Section 63.25-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING AUTOMATIC AUXILIARY BOILERS Requirements for Specific Types of Automatic Auxiliary Boilers § 63.25-7 Exhaust gas boilers. (a) Construction...

  17. 49 CFR 230.30 - Lap-joint seam boilers.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Lap-joint seam boilers. 230.30 Section 230.30..., 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...

  18. Numerical simulations of the industrial circulating fluidized bed boiler under air- and oxy-fuel combustion

    International Nuclear Information System (INIS)

    Adamczyk, Wojciech P.; Kozołub, Paweł; Klimanek, Adam; Białecki, Ryszard A.; Andrzejczyk, Marek; Klajny, Marcin

    2015-01-01

    Measured and numerical results of air-fuel combustion process within large scale industrial circulating fluidized bed (CFB) boiler is presented in this paper. For numerical simulations the industrial compact CFB boiler was selected. Numerical simulations were carried out using three-dimensional model where the dense particulate transport phenomenon was simultaneously modelled with combustion process. The fluidization process was modelled using the hybrid Euler-Lagrange approach. The impact of the geometrical model simplification on predicted mass distribution and temperature profiles over CFB boiler combustion chamber two kinds of geometrical models were used, namely the complete model which consist of combustion chamber, solid separators, external solid super-heaters and simplified boiler geometry which was reduced to the combustion chamber. The evaluated temperature and pressure profiles during numerical simulations were compared against measured data collected during boiler air-fuel operation. Collected data was also used for validating numerical model of the oxy-fuel combustion model. Stability of the model and its sensitivity on changes of several input parameters were studied. The comparison of the pressure and temperature profiles for all considered cases gave comparable trends in contrary to measured data. Moreover, some additional test was carried out the check the influence of radiative heat transfer on predicted temperature profile within the CFB boiler. - Highlights: • Hybrid Euler-Lagrange approach was used for modelling particle transport, air- and oxy-fuel combustion process. • Numerical results were validated against measured data. • The influence of different boiler operating conditions on calculated temperature profile was investigated. • New strategy for resolving particle transport in circulating fluidized bed was shown

  19. Lauryl Amine as heavy metal collector of boiler ash from pulp and paper mill waste

    Science.gov (United States)

    Sembiring, M. P.; Kaban, J.; Bangun, N.; Saputra, E.

    2018-04-01

    Theincreasing of demand of pulp and paper products, will following with the growing the pulp and paper industryand generate significant mill waste. The total waste reached 1/3 of the amount raw materials used and ash boiler is the waste with the largest percentage of 52%. For that it takes effort to manage the existing waste. The boiler ash contained the chemical elements, it can be utilized such as fertilizer, because it also contains transition metals in form of heavy metal such as Cadmium (Cd), Cobalt (Co), Chrome (Cr), Cupprum (Cu), Ferrum (Fe), Nickel (Ni), and Zinc (Zn), the use of boiler ash must follow the threshold specified by the Government. Several studies have been undertaken to reduce and extract heavy metals from ash and sand of the boiler by using carbon dioxide as its ligand. Eelectrochemical method was used to remove and recovery of heavy metals from the incenerator. This study focused on removal of heavy metals using Lauryl Amine as collector and three solvents namely Dichloromethane, Ethanol and n-Hexane. The treatmentswas able to extract the heavy metal and generally reduce the heavy metal content of ash boiler pulp and paper mill waste. The combination treatment used toreduce the heavy metal content of 5 gram Lauryl Amine collector in Dichloromethane solvent for 4 hours process time.

  20. The recovery model and complex health needs: what health psychology can learn from mental health and substance misuse service provision.

    Science.gov (United States)

    Webb, Lucy

    2012-07-01

    This article reviews key arguments around evidence-based practice and outlines the methodological demands for effective adoption of recovery model principles. The recovery model is outlined and demonstrated as compatible with current needs in substance misuse service provision. However, the concepts of evidence-based practice and the recovery model are currently incompatible unless the current value system of evidence-based practice changes to accommodate the methodologies demanded by the recovery model. It is suggested that critical health psychology has an important role to play in widening the scope of evidence-based practice to better accommodate complex social health needs.

  1. Practical model for economic optimization of a heat recovery plate heat exchanger and its examination

    Energy Technology Data Exchange (ETDEWEB)

    Lepach, T.; Marttila, E.; Hammo, S.

    1997-12-31

    This report presents a practical model for designers whose job it is to dimension a plate heat exchanger used especially in heat recovery systems for ventilation. Special attention was given to the economic optimization of such a unit. The first part of the report presents the most important types of heat exchangers and then goes on to present those that are normally used in ventilation systems for heat recovery. The second part discusses the operating costs, investments required and the savings in costs that can be achieved through heat recovery. The third part takes a look at the theory of heat transfer and the characteristics of heat exchanger. In the finally part, a utilization of this model is presented. The results from this are discussed in the following. The developed equations have been calculated and plotted by the use of the numeric software MATLAB. The code used for calculation with MATLAB is listed in the appendix. (orig.) 16 refs.

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

    International Nuclear Information System (INIS)

    Liu, Xingrang; Bansal, R.C.

    2014-01-01

    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

  3. Monitoring and performance analysis of AGR boilers during commissioning and power raising

    International Nuclear Information System (INIS)

    El-Nagdy, M.; Harrison, R.M.

    1984-01-01

    The installed boiler plant, for two 1300 MW AGR stations, is comprehensively instrumented for boiler control, performance assessment and component monitoring to ensure the integrity and safe operation of the plant during normal and faulty operating conditions. Plant instrumentation and computer systems installed at site for vibration analysis during the engineering runs and data acquisition during the power raising stage have been described. The results, from early rig investigations and the vibration testing during the unfueled engineering runs, indicate that the behaviour of the plant within the practical range of operating conditions is free from vibration problems. Also the analysis of the steady state thermal and hydrodynamic behaviour of the boiler plant during the power raising phase confirms the methods and computer models used for the boiler design. (author)

  4. Electrical design requirements for electrode boilers for nuclear plants

    International Nuclear Information System (INIS)

    Kempker, M.J.

    1979-01-01

    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

  5. Environmental performance assessment of utility boiler energy conversion systems

    International Nuclear Information System (INIS)

    Li, Changchun; Gillum, Craig; Toupin, Kevin; Park, Young Ho; Donaldson, Burl

    2016-01-01

    Highlights: • Sustainability analyses of utility boilers are performed. • Natural gas fired boilers have the least CO_2 emissions in fossil fueled boilers. • Solar boilers rank last with an emergy yield ratio of 1.2. • Biomass boilers have the best emergy sustainability index. - Abstract: A significant amount of global electric power generation is produced from the combustion of fossil fuels. Steam boilers are one of the most important components for steam and electricity production. The objective of this paper is to establish a theoretical framework for the sustainability analysis of a utility boiler. These analyses can be used by decision-makers to diagnose and optimize the sustainability of a utility boiler. Seven utility boiler systems are analyzed using energy and embodied solar energy (emergy) principles in order to evaluate their environmental efficiencies. They include a subcritical coal fired boiler, a supercritical coal fired boiler, an oil fired boiler, a natural gas fired boiler, a concentrating solar power boiler utilizing a tower configuration, a biomass boiler, and a refuse derived fuel boiler. Their relative environmental impacts were compared. The results show that the natural gas boiler has significantly lower CO_2 emission than an equivalent coal or oil fired boiler. The refuse derived fuel boiler has about the same CO_2 emissions as the natural gas boiler. The emergy sustainability index of a utility boiler system is determined as the measure of its sustainability from an environmental perspective. Our analyses results indicate that the natural gas boiler has a relatively high emergy sustainability index compared to other fossil fuel boilers. Converting existing coal boilers to natural gas boilers is a feasible option to achieve better sustainability. The results also show that the biomass boiler has the best emergy sustainability index and it will remain a means to utilize the renewable energy within the Rankine steam cycle. Before

  6. Dynamic simulation of a circulating fluidized bed boiler system part II: Simulation of a boiler system operating in a power plant

    International Nuclear Information System (INIS)

    Kim, Seong Il; Choi, Sang Min; Yang, Jong In

    2016-01-01

    A case of dynamic performance simulation model of a CFB boiler is presented in this study. The dynamic system of a CFB boiler in an operating power plant and the transient behavior of sub-models is described in the accompanying paper, Part I. The current paper, Part II, describes the model extension for the CFB boiler system in a power plant. The open loop model in Paper I was expanded by applying a set of PID (Proportional-integral-differential) control loops. In the control loop, pressure, temperature, mass flow rate of the main steam, the drum water level and the oxygen level at the stack were controlled. Dynamic performance was simulated to check the response of the closed control loop. Finally, performance of the total boiler system for a range of operation load of the power plant was simulated, where the parameters were calculated and control variables were maintained at the set values by PID control. Dynamic performance of a boiler at a selected load variation case was simulated and compared with actual measurements and their transient response characteristics were discussed. The simulation can also directly produce useful operation parameters, which are not measurable, but could be used for engineering evaluation

  7. Dynamic simulation of a circulating fluidized bed boiler system part II: Simulation of a boiler system operating in a power plant

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Il; Choi, Sang Min; Yang, Jong In [Dept. of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon(Korea, Republic of)

    2016-12-15

    A case of dynamic performance simulation model of a CFB boiler is presented in this study. The dynamic system of a CFB boiler in an operating power plant and the transient behavior of sub-models is described in the accompanying paper, Part I. The current paper, Part II, describes the model extension for the CFB boiler system in a power plant. The open loop model in Paper I was expanded by applying a set of PID (Proportional-integral-differential) control loops. In the control loop, pressure, temperature, mass flow rate of the main steam, the drum water level and the oxygen level at the stack were controlled. Dynamic performance was simulated to check the response of the closed control loop. Finally, performance of the total boiler system for a range of operation load of the power plant was simulated, where the parameters were calculated and control variables were maintained at the set values by PID control. Dynamic performance of a boiler at a selected load variation case was simulated and compared with actual measurements and their transient response characteristics were discussed. The simulation can also directly produce useful operation parameters, which are not measurable, but could be used for engineering evaluation.

  8. Modeling imbalanced economic recovery following a natural disaster using input-output analysis.

    Science.gov (United States)

    Li, Jun; Crawford-Brown, Douglas; Syddall, Mark; Guan, Dabo

    2013-10-01

    Input-output analysis is frequently used in studies of large-scale weather-related (e.g., Hurricanes and flooding) disruption of a regional economy. The economy after a sudden catastrophe shows a multitude of imbalances with respect to demand and production and may take months or years to recover. However, there is no consensus about how the economy recovers. This article presents a theoretical route map for imbalanced economic recovery called dynamic inequalities. Subsequently, it is applied to a hypothetical postdisaster economic scenario of flooding in London around the year 2020 to assess the influence of future shocks to a regional economy and suggest adaptation measures. Economic projections are produced by a macro econometric model and used as baseline conditions. The results suggest that London's economy would recover over approximately 70 months by applying a proportional rationing scheme under the assumption of initial 50% labor loss (with full recovery in six months), 40% initial loss to service sectors, and 10-30% initial loss to other sectors. The results also suggest that imbalance will be the norm during the postdisaster period of economic recovery even though balance may occur temporarily. Model sensitivity analysis suggests that a proportional rationing scheme may be an effective strategy to apply during postdisaster economic reconstruction, and that policies in transportation recovery and in health care are essential for effective postdisaster economic recovery. © 2013 Society for Risk Analysis.

  9. Chemical cleaning of UK AGR boilers

    International Nuclear Information System (INIS)

    Rudge, A.; Turner, P.; Ghosh, S.; Clary, W.; Tice, D.R.

    2002-01-01

    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)

  10. Experimental validation of a dynamic waste heat recovery system model for control purposes

    NARCIS (Netherlands)

    Feru, E.; Kupper, F.; Rojer, C.; Seykens, X.L.J.; Scappin, F.; Willems, F.P.T.; Smits, Jeroen; Jager, de A.G.; Steinbuch, M.

    2013-01-01

    This paper presents the identification and validation of a dynamic Waste Heat Recovery (WHR) system model. Driven by upcoming CO2 emission targets and increasing fuel costs, engine exhaust gas heat utilization has recently attracted much attention to improve fuel efficiency, especially for

  11. Modeling for Endangered-Species Recovery: Gray Wolves in the Western Great Lakes Region

    Science.gov (United States)

    Jean Fitts Cochrane; Robert G. Haight; Anthony M. Starfield

    2003-01-01

    The Federal Endangered Species Act is intended to conserve endangered and threatened species and their habitats and to improve the species' status so that they no longer need protection under the Act. In the process of planning the recovery of threatened or endangered species, the U.S. Fish and Wildlife Service increasingly uses demographic models to predict...

  12. A new method for predicting functional recovery of stroke patients with hemiplegia: logarithmic modelling.

    Science.gov (United States)

    Koyama, Tetsuo; Matsumoto, Kenji; Okuno, Taiji; Domen, Kazuhisa

    2005-10-01

    To examine the validity and applicability of logarithmic modelling for predicting functional recovery of stroke patients with hemiplegia. Longitudinal postal survey. Stroke patients with hemiplegia staying in a long-term rehabilitation facility, who had been referred from acute medical service 30-60 days after onset. Functional Independence Measure (FIM) scores were periodically assessed during hospitalization. For each individual, a logarithmic formula that was scaled by an interval increase in FIM scores during the initial 2-6 weeks was used for predicting functional recovery. For the study, we recruited 18 patients who showed a wide variety of disability levels on admission (FIM scores 25-107). For each patient, the predicted FIM scores derived from the logarithmic formula matched the actual change in FIM scores. The changes predicted the recovery of motor rather than cognitive functions. Regression analysis showed a close fit between logarithmic modelling and actual FIM scores (across-subject R2 = 0.945). Provided with two initial time-point samplings, logarithmic modelling allows accurate prediction of functional recovery for individuals. Because the modelling is mathematically simple, it can be widely applied in daily clinical practice.

  13. Grain Size and Parameter Recovery with TIMSS and the General Diagnostic Model

    Science.gov (United States)

    Skaggs, Gary; Wilkins, Jesse L. M.; Hein, Serge F.

    2016-01-01

    The purpose of this study was to explore the degree of grain size of the attributes and the sample sizes that can support accurate parameter recovery with the General Diagnostic Model (GDM) for a large-scale international assessment. In this resampling study, bootstrap samples were obtained from the 2003 Grade 8 TIMSS in Mathematics at varying…

  14. Lactic Acid Recovery in Electro-Enhanced Dialysis: Modelling and Validation

    DEFF Research Database (Denmark)

    Prado Rubio, Oscar Andres; Jørgensen, Sten Bay; Jonsson, Gunnar Eigil

    2009-01-01

    and migration across the boundary layers and membranes. The model is validated for Donnan dialysis recovery of different monoprotic carboxylic acids. Simulations are used to evaluate the potential enhancement of lactate fluxes under current load conditions, referred as Electro-Enhanced Dialysis operation...

  15. Functional recovery after facial nerve cable grafting in a rodent model.

    NARCIS (Netherlands)

    Hohman, M.H.; Kleiss, I.J.; Knox, C.J.; Weinberg, J.S.; Heaton, J.T.; Hadlock, T.A.

    2014-01-01

    IMPORTANCE: Cable grafting is widely considered to be the preferred alternative to primary repair of the injured facial nerve; however, quantitative comparison of the 2 techniques has not been previously undertaken in a rodent model. OBJECTIVE: To establish functional recovery parameters after

  16. Recovery Act. Development of a Model Energy Conservation Training Program

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2012-07-05

    The overall objective of this project was to develop an updated model Energy Conservation training program for stationary engineers. This revision to the IUOE National Training Fund’s existing Energy Conservation training curriculum is designed to enable stationary engineers to incorporate essential energy management into routine building operation and maintenance tasks. The curriculum uses a blended learning approach that includes classroom, hands-on, computer simulation and web-based training in addition to a portfolio requirement for a workplace-based learning application. The Energy Conservation training program goal is development of a workforce that can maintain new and existing commercial buildings at optimum energy performance levels. The grant start date was July 6, 2010 and the project continued through September 30, 2012, including a three month non-funded extension.

  17. Treatment of Berkeley boilers in Studsvik. Project description and experiences - Berkeley Boilers Project

    International Nuclear Information System (INIS)

    Saul, Dave; Davidson, Gavin; Wirendal, Bo

    2014-01-01

    In November 2011 Studsvik was awarded a contract to transport five decommissioned boilers from the Berkeley Nuclear Licensed Site in the UK to the Studsvik Nuclear Site in Sweden for metal treatment and recycling. A key objective of the project was to remove the boilers from the site by 31 March 2012 and this was successfully achieved with all boilers off site by 22 March and delivered to Studsvik on 6 April. In November 2012 Studsvik was awarded a further contract for the remaining ten Berkeley Boilers with the requirement to remove all boilers from the Berkeley site by 31 March 2013. Again this was successfully achieved ahead of programme with all boilers in Sweden by 1 April 2013. A total of nine boilers have now been processed and all remaining boilers will be completed by end of September 2014. The projects have had many challenges including a very tight timescale and both have been successfully delivered to cost and ahead of the baseline programme. This paper describes the project and the experience gained from treatment of the boilers to date. (authors)

  18. Modeling the economic costs of disasters and recovery: analysis using a dynamic computable general equilibrium model

    Science.gov (United States)

    Xie, W.; Li, N.; Wu, J.-D.; Hao, X.-L.

    2014-04-01

    Disaster damages have negative effects on the economy, whereas reconstruction investment has positive effects. The aim of this study is to model economic causes of disasters and recovery involving the positive effects of reconstruction activities. Computable general equilibrium (CGE) model is a promising approach because it can incorporate these two kinds of shocks into a unified framework and furthermore avoid the double-counting problem. In order to factor both shocks into the CGE model, direct loss is set as the amount of capital stock reduced on the supply side of the economy; a portion of investments restores the capital stock in an existing period; an investment-driven dynamic model is formulated according to available reconstruction data, and the rest of a given country's saving is set as an endogenous variable to balance the fixed investment. The 2008 Wenchuan Earthquake is selected as a case study to illustrate the model, and three scenarios are constructed: S0 (no disaster occurs), S1 (disaster occurs with reconstruction investment) and S2 (disaster occurs without reconstruction investment). S0 is taken as business as usual, and the differences between S1 and S0 and that between S2 and S0 can be interpreted as economic losses including reconstruction and excluding reconstruction, respectively. The study showed that output from S1 is found to be closer to real data than that from S2. Economic loss under S2 is roughly 1.5 times that under S1. The gap in the economic aggregate between S1 and S0 is reduced to 3% at the end of government-led reconstruction activity, a level that should take another four years to achieve under S2.

  19. Preoperative predictive model of recovery of urinary continence after radical prostatectomy

    Science.gov (United States)

    Matsushita, Kazuhito; Kent, Matthew T.; Vickers, Andrew J.; von Bodman, Christian; Bernstein, Melanie; Touijer, Karim A.; Coleman, Jonathan; Laudone, Vincent; Scardino, Peter T.; Eastham, James A.; Akin, Oguz; Sandhu, Jaspreet S.

    2016-01-01

    Objective ● To build a predictive model of urinary continence recovery following radical prostatectomy that incorporates magnetic resonance imaging parameters and clinical data. Patients and Methods ● We conducted a retrospective review of data from 2,849 patients who underwent pelvic staging magnetic resonance imaging prior to radical prostatectomy from November 2001 to June 2010. ● We used logistic regression to evaluate the association between each MRI variable and continence at 6 or 12 months, adjusting for age, body mass index (BMI), and American Society of Anesthesiologists (ASA) score and then used multivariable logistic regression to create our model. ● A nomogram was constructed using the multivariable logistic regression models. Results ● In total, 68% (n=1,742/2,559) and 82% (n=2,205/2,689) regained function at 6 and 12 months, respectively. ● In the base model, age, BMI, and ASA score were significant predictors of continence at 6 or 12 months on univariate analysis (p <0.005). ● Among the preoperative magnetic resonance imaging measurements, membranous urethral length, which showed great significance, was incorporated into the base model to create the full model. ● For continence recovery at 6 months, the addition of membranous urethral length increased the AUC to 0.664 for the validation set, an increase of 0.064 over the base model. For continence recovery at 12 months, the AUC was 0.674, an increase of 0.085 over the base model. Conclusions ● Using our model, the likelihood of continence recovery increases with membranous urethral length and decreases with age, body mass index, and ASA score. ● This model could be used for patient counseling and for the identification of patients at high risk for urinary incontinence in whom to study changes in operative technique that improve urinary function after radical prostatectomy. PMID:25682782

  20. Imulation of temperature field in swirl pulverized coal boiler

    Science.gov (United States)

    Lv, Wei; Wu, Weifeng; Chen, Chen; Chen, Weifeng; Qi, Guoli; Zhang, Songsong

    2018-02-01

    In order to achieve the goal of energy saving and emission reduction and energy efficient utilization, taking a 58MW swirl pulverized coal boiler as the research object, the three-dimensional model of the rotor is established. According to the principle of CFD, basic assumptions and boundary conditions are selected, the temperature field in the furnace of 6 kinds of working conditions is numerically solved, and the temperature distribution in the furnace is analyzed. The calculation results show that the temperature of the working condition 1 is in good agreement with the experimental data, and the error is less than 10%,the results provide a theoretical basis for the following calculation. Through the comparison of the results of the 6 conditions, it is found that the working condition 3 is the best operating condition of the pulverized coal boiler.

  1. Multi-pressure boiler thermodynamics analysis code

    International Nuclear Information System (INIS)

    Lorenzoni, G.

    1992-01-01

    A new method and the relative FORTRAN program for the thermodynamics design analysis of a multipressure boiler are reported. This method permits the thermodynamics design optimization with regard to total exergy production and a preliminary costs

  2. Pirotubular boilers design. Diseno de calderas pirotubulares

    Energy Technology Data Exchange (ETDEWEB)

    Latre Durso, F. (Geval S.A. (Spain))

    1994-01-01

    This article describes the conceptual design of Pirotubular boilers from the valuable thermal point of view, to the dimensional. This topic is a very tool valuable for professionals of design and for maintenance and operation equipment.

  3. Water side corrosion prevention in boilers

    International Nuclear Information System (INIS)

    Zeid, A.

    1993-01-01

    Corrosion may be defined as a naturally occurring physical and chemical deterioration of a material due to reaction with the environment or surrounding atmosphere. In boilers the material is subjected on both sides to two different media which may cause severe corrosion. At the water side the content of O 2 considered one of the principal factors which determine the extent of corrosion in the boiler tubes. This paper deals with certain conditions that result in the increase of O 2 in the boiler water and hence increase the corrosion rate, to minimize the effect of these conditions a chemical treatment was carried out the results obtained indicated the success of the treatment procedure in corrosion prevention and boiler material protection. The treatment is traditional. But the study indicates how a simple mean could be applied to solve a serious problem. 4 tab

  4. The Vessel Schedule Recovery Problem (VSRP) – A MIP model for handling disruptions in liner shipping

    DEFF Research Database (Denmark)

    Brouer, Berit Dangaard; Dirksen, Jakob; Pisinger, David

    2013-01-01

    or even omitting one. We present the Vessel Schedule Recovery Problem (VSRP) to evaluate a given disruption scenario and to select a recovery action balancing the trade off between increased bunker consumption and the impact on cargo in the remaining network and the customer service level. It is proven...... due to adverse weather conditions, port contingencies, and many other issues. A common scenario for recovering a schedule is to either increase the speed at the cost of a significant increase in the fuel consumption or delaying cargo. Advanced recovery options might exist by swapping two port calls...... that the VSRP is NP-hard. The model is applied to four real life cases from Maersk Line and results are achieved in less than 5seconds with solutions comparable or superior to those chosen by operations managers in real life. Cost savings of up to 58% may be achieved by the suggested solutions compared...

  5. Catalytic burners in larger boiler appliances

    Energy Technology Data Exchange (ETDEWEB)

    Silversand, Fredrik; Persson, Mikael (Catator AB, Lund (Sweden))

    2009-02-15

    This project focuses on the scale up of a Catator's catalytic burner technology to enable retrofit installation in existing boilers and the design of new innovative combinations of catalytic burners and boilers. Different design approaches are discussed and evaluated in the report and suggestions are made concerning scale-up. Preliminary test data, extracted from a large boiler installation are discussed together with an accurate analysis of technical possibilities following an optimization of the boiler design to benefit from the advantages of catalytic combustion. The experimental work was conducted in close collaboration with ICI Caldaie (ICI), located in Verona, Italy. ICI is a leading European boiler manufacturer in the effect segment ranging from about 20 kWt to several MWt. The study shows that it is possibly to scale up the burner technology and to maintain low emissions. The boilers used in the study were designed around conventional combustion and were consequently not optimized for implementation of catalytic burners. From previous experiences it stands clear that the furnace volume can be dramatically decreased when applying catalytic combustion. In flame combustion, this volume is normally dimensioned to avoid flame impingement on cold surfaces and to facilitate completion of the gas-phase reactions. The emissions of nitrogen oxides can be reduced by decreasing the residence time in the furnace. Even with the over-dimensioned furnace used in this study, we easily reached emission values close to 35 mg/kWh. The emissions of carbon monoxide and unburned hydrocarbons were negligible (less than 5 ppmv). It is possible to decrease the emissions of nitrogen oxides further by designing the furnace/boiler around the catalytic burner, as suggested in the report. Simultaneously, the size of the boiler installation can be reduced greatly, which also will result in material savings, i.e. the production cost can be reduced. It is suggested to optimize the

  6. Modelling of a Naphtha Recovery Unit (NRU with Implications for Process Optimization

    Directory of Open Access Journals (Sweden)

    Jiawei Du

    2018-06-01

    Full Text Available The naphtha recovery unit (NRU is an integral part of the processes used in the oil sands industry for bitumen extraction. The principle role of the NRU is to recover naphtha from the tailings for reuse in this process. This process is energy-intensive, and environmental guidelines for naphtha recovery must be met. Steady-state models for the NRU system are developed in this paper using two different approaches. The first approach is a statistical, data-based modelling approach where linear regression models have been developed using Minitab® from plant data collected during a performance test. The second approach involves the development of a first-principles model in Aspen Plus® based on the NRU process flow diagram. A novel refinement to this latter model, called “withdraw and remix”, is proposed based on comparing actual plant data to model predictions around the two units used to separate water and naphtha. The models developed in this paper suggest some interesting ideas for the further optimization of the process, in that it may be possible to achieve the required naphtha recovery using less energy. More plant tests are required to validate these ideas.

  7. Thermal design of horizontal tube boilers: numerical and experimental investigation

    International Nuclear Information System (INIS)

    Roser, Robert

    1999-01-01

    This work concerns the thermal design of kettle re-boilers. 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 modelization of the two-phase flow in the boiler, which is a significant progress compared to current simplified methods. (author) [fr

  8. 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.

  9. Economic valuation of heat pumps and electric boilers in the Danish energy system

    International Nuclear Information System (INIS)

    Nielsen, Maria Grønnegaard; Morales, Juan Miguel; Zugno, Marco; Pedersen, Thomas Engberg; Madsen, Henrik

    2016-01-01

    Highlights: • We assess the economic value of heat pumps and electric boilers in Denmark. • The daily operation of a heat and power system is modeled by stochastic programming. • Deterministic models overestimate the value of heat pumps and electric boilers. • Heat pumps and electric boilers can reduce the cost of operating the Danish system. • Falling power prices may boost the future value of heat pumps and electric boilers. - Abstract: Heat pumps (HP) and electric immersion boilers (EB) have great potential to increase flexibility in energy systems. In parallel, decreasing taxes on electricity-based heat production are creating a more favorable economic environment for the deployment of these units in Denmark. In this paper, the economic value of heat pumps and electric boilers is assessed by simulating their day-to-day market performance using a novel operational strategy based on two-stage stochastic programming. This stochastic model is employed to optimize jointly the daily operation of HPs and EBs along with the Combined Heat and Power (CHP) units in the system. Uncertainty in the heat demand and power price is modeled via scenarios representing different plausible paths for their future evolution. A series of case-studies are performed using real-world data for the heat and power systems in the Copenhagen area during four representative weeks of 2013. We show that the use of stochastic operational models is critical, as standard deterministic models provide an overestimation of the added benefits from the installation of HPs and EBs, thus leading to over-investment in capacity. Furthermore, we perform sensitivity studies to investigate the effect on market performance of varying capacity and efficiency for these units, as well as of different levels of prices in the electricity market. We find that these parameters substantially affect the profitability of heat pumps and electric boilers, hence, they must be carefully assessed by potential

  10. Boiler burden reduced at Bedford site.

    Science.gov (United States)

    Horsley, Chris

    2011-10-01

    With the NHS aiming to reduce its 2007 carbon footprint by 10% by 2015, Chris Horsley, managing director of Babcock Wanson UK, a provider of industrial boilers and burners, thermal oxidisers, air treatment, water treatment, and associated services, looks at how one NHS Trust has approached the challenge, and considerably reduced its carbon emissions, by refurbishing its boiler house and moving from oil to gas-fired steam generation.

  11. Ecological boiler modernization, feasible energy solutions

    International Nuclear Information System (INIS)

    Krcek, F.; Matev, M.; Sykora, J.; Chladek, J.

    2005-01-01

    Alstom Power, s.r.o., ALSTOM GROUP in Brno, Czech Republic is a successor of PBS (First Brno Machine Works). PBS was a well-known company in Bulgaria - mainly as Heating Power Plant (HPP) and Industrial Plant supplier of boilers, industrial steam turbines, milling systems, heat exchangers Btc. PBS has been privatised in two stages starting at1993 year. Alstom recently deals with boiler and heat exchanger products. Industrial turbine but has been sold to Siemens in 2004

  12. Gas fired boilers and atmospheric pollution

    International Nuclear Information System (INIS)

    Chiaranello, J.M.

    1991-01-01

    A general analysis concerning atmospheric pollution is presented: chemical composition and vertical distribution of atmosphere and pollutants, chemical reactions, ozone destruction and production cycles, COx, NOx and SOx pollutions. The gas fired boiler number and repartition in France are presented and the associated pollution is analyzed (CO2, CO, NOx) and quantified. Various pollution control technics concerning gas fired boiler pollutants are described and a pollution criterion for clean gas fired generators is proposed

  13. Model predictive and reallocation problem for CubeSat fault recovery and attitude control

    Science.gov (United States)

    Franchi, Loris; Feruglio, Lorenzo; Mozzillo, Raffaele; Corpino, Sabrina

    2018-01-01

    In recent years, thanks to the increase of the know-how on machine-learning techniques and the advance of the computational capabilities of on-board processing, expensive computing algorithms, such as Model Predictive Control, have begun to spread in space applications even on small on-board processor. The paper presents an algorithm for an optimal fault recovery of a 3U CubeSat, developed in MathWorks Matlab & Simulink environment. This algorithm involves optimization techniques aiming at obtaining the optimal recovery solution, and involves a Model Predictive Control approach for the attitude control. The simulated system is a CubeSat in Low Earth Orbit: the attitude control is performed with three magnetic torquers and a single reaction wheel. The simulation neglects the errors in the attitude determination of the satellite, and focuses on the recovery approach and control method. The optimal recovery approach takes advantage of the properties of magnetic actuation, which gives the possibility of the redistribution of the control action when a fault occurs on a single magnetic torquer, even in absence of redundant actuators. In addition, the paper presents the results of the implementation of Model Predictive approach to control the attitude of the satellite.

  14. a Study of Using Hydrogen Gas for Steam Boiler in CHOLOR- Alkali Manufacturing

    Science.gov (United States)

    Peantong, Sasitorn; Tangjitsitcharoen, Somkiat

    2017-06-01

    Main products of manufacturing of Cholor - Alkali, which commonly known as industrial chemical, are chlorine gas (Cl2), Sodium Hydroxide (NaOH) and hydrogen gas (H2). Chorine gas and sodium hydroxide are two main products for commercial profit; where hydrogen gas is by product. Most industries release hydrogen gas to atmosphere as it is non-profitable and less commercial scale. This study aims to make the most use of hydrogen as a substitute energy of natural gas for steam boiler to save energy cost. The second target of this study is to reduce level of CO2 release to air as a consequence of boiler combustion. This study suggests to install boiler that bases on hydrogen as main power with a high turndown ratio of at least 1:6. However, this case study uses boiler with two mode such as natural gas (NG) mode and mixed mode as they need to be flexible for production. Never the less, the best boiler selection is to use single mode energy of hydrogen. The most concerned issue about hydrogen gas is explosion during combustion stage. Stabilization measures at emergency stop is introduced to control H2 pressure to protect the explosion. This study varies ratio of natural gas to hydrogen gas to find the optimal level of two energy sources for boiler and measure total consumption through costing model; where CO2 level is measured at the boiler stack. The result of this study shows that hydrogen gas can be a substitute energy with natural gas and can reduce cost. Natural gas cost saving is 248,846 baht per month and reduce level of NOx is 80 ppm 7% O2 and 2 % of CO2 release to air as a consequence of boiler combustion.

  15. A semianalytical model to predict recovery of light, nonaqueous phase liquids from unconfined aquifers

    International Nuclear Information System (INIS)

    Waddill, D.W.

    1997-01-01

    This paper describes the development and testing of a semianalytical model that may be used to design LNAPL containment and recovery systems at spill sites. The objective of this study was to derive an enhanced semianalytical algorithm for calculating recovery and trapping of free phase oil. The enhancements were derived and evaluated by comparison with an established numerical model that describes transient flow of oil and water. The semianalytical model employs an analytical solution for steady-state drawdown in an unconfined aquifer due to water pumping. When pumping rates are sufficient to contain the separate phase plume, the model calculates recoverable and residual oil volumes based on the initial free oil distribution. Refinements were implemented to calculate the water-table drawdown and the maximum unsaturated zone residual saturation (S og ) as functions of soil type. Also the influence of hysteresis on the oil-water capillary fringe was incorporated into the calculation of oil trapping below a rising oil-water interface. A method was derived to reduce saturated zone trapping to account for oil recovery that occurs while pumping proceeds. The above enhancements yielded close agreement between the semianalytical model and the transient model predictions of recoverable oil and residua oil in the unsaturated and saturated zones. The models were compared for hypothetical gasoline spills in a sandy and a silt loam soil, using a range of pumping rates and regional water-table fluctuations. Field data from a pipeline leak were evaluated by the semianalytical model for hypothetical scenarios involving oil recovery from three wells and a falling regional water table

  16. Modelling of an industrial NGL-Recovery unit considering environmental and economic impacts

    International Nuclear Information System (INIS)

    Sharratt, P. N.; Hernandez-Enriquez, A.; Flores-Tlacuahuac, A.

    2009-01-01

    In this work, an integrated model is presented that identifies key areas in the operation of a cryogenic NGL-recovery unit. This methodology sets out to provide deep understanding of various interrelationship across multiple plant operating factors including reliability, which could be essential for substantial improvement of process performance. The integrated model has been developed to predict the economic and environmental impacts of a real cryogenic unit (600 MMCUF/D) during normal operation, and has been built in Aspen TM. (Author)

  17. Assessment of physical workload in boiler operations.

    Science.gov (United States)

    Rodrigues, Valéria Antônia Justino; Braga, Camila Soares; Campos, Julio César Costa; Souza, Amaury Paulo de; Minette, Luciano José; Sensato, Guilherme Luciano; Moraes, Angelo Casali de; Silva, Emília Pio da

    2012-01-01

    The use of boiler wood-fired is fairly common equipment utilized in steam generation for energy production in small industries. The boiler activities are considered dangerous and heavy, mainly due to risks of explosions and the lack of mechanization of the process. This study assessed the burden of physical labor that operators of boilers are subjected during the workday. Assessment of these conditions was carried out through quantitative and qualitative measurements. A heart rate monitor, a wet-bulb globe thermometer (WBGT), a tape-measure and a digital infrared camera were the instruments used to collect the quantitative data. The Nordic Questionnaire and the Painful Areas Diagram were used to relate the health problems of the boiler operator with activity. With study, was concluded that the boiler activity may cause pains in the body of intensity different, muscle fatigue and diseases due to excessive weight and the exposure to heat. The research contributed to improve the boiler operator's workplace and working conditions.

  18. Increasing the thermal efficiency of boiler plant

    Directory of Open Access Journals (Sweden)

    Uyanchinov Evgeniy

    2017-01-01

    Full Text Available The thermal efficiency increase of boiler plant is actual task of scientific and technical researches. The optimization of boiler operating conditions is task complex, which determine by most probable average load of boiler, operating time and characteristics of the auxiliary equipment. The work purpose – the determination of thermodynamic efficiency increase ways for boiler plant with a gas-tube boiler. The tasks, solved at the research are the calculation of heat and fuel demand, the exergetic analysis of boilerhouse and heat network equipment, the determination of hydraulic losses and exergy losses due to restriction. The calculation was shown that the exergy destruction can be reduced by 2.39% due to excess air reducing to 10%; in addition the oxygen enrichment of air can be used that leads to reducing of the exergy destruction rate. The processes of carbon deposition from the side of flame and processes of scale formation on the water side leads to about 4.58% losses of fuel energy at gas-tube boiler. It was shown that the exergy losses may be reduced by 2.31% due to stack gases temperature reducing to 148 °C.

  19. Effect of Pellet Boiler Exhaust on Secondary Organic Aerosol Formation from α-Pinene.

    Science.gov (United States)

    Kari, Eetu; Hao, Liqing; Yli-Pirilä, Pasi; Leskinen, Ari; Kortelainen, Miika; Grigonyte, Julija; Worsnop, Douglas R; Jokiniemi, Jorma; Sippula, Olli; Faiola, Celia L; Virtanen, Annele

    2017-02-07

    Interactions between anthropogenic and biogenic emissions, and implications for aerosol production, have raised particular scientific interest. Despite active research in this area, real anthropogenic emission sources have not been exploited for anthropogenic-biogenic interaction studies until now. This work examines these interactions using α-pinene and pellet boiler emissions as a model test system. The impact of pellet boiler emissions on secondary organic aerosol (SOA) formation from α-pinene photo-oxidation was studied under atmospherically relevant conditions in an environmental chamber. The aim of this study was to identify which of the major pellet exhaust components (including high nitrogen oxide (NO x ), primary particles, or a combination of the two) affected SOA formation from α-pinene. Results demonstrated that high NO x concentrations emitted by the pellet boiler reduced SOA yields from α-pinene, whereas the chemical properties of the primary particles emitted by the pellet boiler had no effect on observed SOA yields. The maximum SOA yield of α-pinene in the presence of pellet boiler exhaust (under high-NO x conditions) was 18.7% and in the absence of pellet boiler exhaust (under low-NO x conditions) was 34.1%. The reduced SOA yield under high-NO x conditions was caused by changes in gas-phase chemistry that led to the formation of organonitrate compounds.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

    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.

  1. 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.

  2. Accuracy of W' Recovery Kinetics in High Performance Cyclists - Modelling Intermittent Work Capacity.

    Science.gov (United States)

    Bartram, Jason C; Thewlis, Dominic; Martin, David T; Norton, Kevin I

    2017-10-16

    With knowledge of an individual's critical power (CP) and W' the SKIBA 2 model provides a framework with which to track W' balance during intermittent high intensity work bouts. There are fears the time constant controlling the recovery rate of W' (τ W' ) may require refinement to enable effective use in an elite population. Four elite endurance cyclists completed an array of intermittent exercise protocols to volitional exhaustion. Each protocol lasted approximately 3.5-6 minutes and featured a range of recovery intensities, set in relation to athlete's CPs (DCP). Using the framework of the SKIBA 2 model, the τ W ' values were modified for each protocol to achieve an accurate W' at volitional exhaustion. Modified τ W ' values were compared to equivalent SKIBA 2 τ W ' values to assess the difference in recovery rates for this population. Plotting modified τ W ' values against DCP showed the adjusted relationship between work-rate and recovery-rate. Comparing modified τ W' values against the SKIBA 2 τ W' values showed a negative bias of 112±46s (mean±95%CL), suggesting athlete's recovered W' faster than predicted by SKIBA 2 (p=0.0001). The modified τ W' to DCP relationship was best described by a power function: τ W' =2287.2∗D CP -0.688 (R 2 = 0.433). The current SKIBA 2 model is not appropriate for use in elite cyclists as it under predicts the recovery rate of W'. The modified τ W' equation presented will require validation, but appears more appropriate for high performance athletes. Individual τ W' relationships may be necessary in order to maximise the model's validity.

  3. Pelly Crossing wood chip boiler

    Energy Technology Data Exchange (ETDEWEB)

    1985-03-11

    The Pelly wood chip project has demonstrated that wood chips are a successful fuel for space and domestic water heating in a northern climate. Pelly Crossing was chosen as a demonstration site for the following reasons: its extreme temperatures, an abundant local supply of resource material, the high cost of fuel oil heating and a lack of local employment. The major obstacle to the smooth operation of the boiler system was the poor quality of the chip supply. The production of poor quality chips has been caused by inadequate operation and maintenance of the chipper. Dull knives and faulty anvil adjustments produced chips and splinters far in excess of the one centimetre size specified for the system's design. Unanticipated complications have caused costs of the system to be higher than expected by approximately $15,000. The actual cost of the project was approximately $165,000. The first year of the system's operation was expected to accrue $11,600 in heating cost savings. This estimate was impossible to confirm given the system's irregular operation and incremental costs. Consistent operation of the system for a period of at least one year plus the installation of monitoring devices will allow the cost effectiveness to be calculated. The wood chip system's impact on the environment was estimated to be minimal. Wood chip burning was considered cleaner and safer than cordwood burning. 9 refs., 6 figs., 6 tabs.

  4. A study by simulation of dynamic instability in boilers using the NUMEL/DYMEL suite of programmes

    International Nuclear Information System (INIS)

    Jeffries, T.O.

    1985-01-01

    Tube-to-tube instability in a once through sodium heated boiler has been studied using the finite difference model developed by the CEGB and embodied in the NUMEL and DYMEL compute codes. The method used was to simulate the boiler and then carry out frequency response tests, as one would on a real boiler. The advantages of using the simulation model compared with using the real system are the ease with which experiments may be performed and the ease of access to a wide range of parameters which could only be obtained approximately, if at all, from a real boiler. The advantage is that validation of the model is only approximate though in the case of sodium heated boilers, conditions are similar to those in electrically heated rigs used for validation. The study led to an understanding of how such a boiler should be operated to avoid tube-to-tube instability and with the detailed temperature profiles available from NUMEL it was possible to develop existing theory to predict boiler transfer functions similar to those observed in the frequency response tests. (author)

  5. 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

    This is the Final Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project was 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) provided co-funding for this program. This project included research on: (1) In furnace NOx control; (2) Impacts of combustion modifications on boiler operation; (3) Selective Catalytic Reduction (SCR) catalyst testing and (4) Ammonia adsorption/removal on fly ash. Important accomplishments were achieved in all aspects of the project. Rich Reagent Injection (RRI), an in-furnace NOx reduction strategy based on injecting urea or anhydrous ammonia into fuel rich regions in the lower furnace, was evaluated for cyclone-barrel and PC fired utility boilers. Field tests successfully demonstrated the ability of the RRI process to significantly reduce NOx emissions from a staged cyclone-fired furnace operating with overfire air. The field tests also verified the accuracy of the Computational Fluid Dynamic (CFD) modeling used to develop the RRI design and highlighted the importance of using CFD modeling to properly locate and configure the reagent injectors within the furnace. Low NOx firing conditions can adversely impact boiler operation due to increased waterwall wastage (corrosion) and increased soot production. A corrosion monitoring system that uses electrochemical noise (ECN) corrosion probes to monitor, on a real-time basis, high temperature corrosion events within the boiler was evaluated. Field tests were successfully conducted at two plants. The Ohio Coal Development Office provided financial assistance to perform the field tests. To investigate soot behavior, an advanced model to predict soot production and destruction was implemented into an existing reacting CFD modeling tool. Comparisons between experimental data collected

  6. Boiler and HRSG tube failures. Lesson 4: Hydrogen damage

    Energy Technology Data Exchange (ETDEWEB)

    Dooley, R. Barry; Bursik, Albert

    2010-02-15

    University 101 courses are typically designed to help incoming first-year undergraduate students to adjust to the university, develop a better understanding of the college environment, and acquire essential academic success skills. Why are we offering a special Boiler and HRSG Tube Failures PPChem 101? The answer is simple, yet very conclusive: There is a lack of knowledge on the identification of tube failure mechanisms and for the implementation of adequate counteractions in many power plants, particularly at industrial power and steam generators. There is a lack of knowledge to prevent repeat tube failures. The vast majority of BTF/HTF have been, and continue to be, repeat failures. It is hoped that the information about the failure mechanisms of BTF supplied in this course will help to put plant engineers and chemists on the right track. The major goal of this course is the avoidance of repeat BTF. This fourth lesson is focused on hydrogen damage of water-touched tubes in conventional boilers and in the high-pressure evaporators of heat recovery steam generators. (orig.)

  7. Boiler and HRSG tube failures. Lesson 5. Caustic gouging

    Energy Technology Data Exchange (ETDEWEB)

    Dooley, Barry R.; Bursik, Albert

    2010-03-15

    University 101 courses are typically designed to help incoming first-year undergraduate students to adjust to the university, develop a better understanding of the college environment, and acquire essential academic success skills. Why are we offering a special Boiler and HRSG Tube Failures PPChem 101? The answer is simple, yet very conclusive: - There is a lack of knowledge on the identification of tube failure mechanisms and for the implementation of adequate counteractions in many power plants, particularly at industrial power and steam generators. - There is a lack of knowledge to prevent repeat tube failures. The vast majority of BTF/HTF have been, and continue to be, repeat failures. It is hoped that the information about the failure mechanisms of BTF supplied in this course will help to put plant engineers and chemists on the right track. The major goal of this course is the avoidance of repeat BTF. This fifth lesson is focused on caustic gouging of water-touched tubes in conventional boilers and in the high-pressure evaporators of heat recovery steam generators. (orig.)

  8. Application of Evaporative Cooling for the Condensation of Water Vapors from a Flue Gas Waste Heat Boilers CCP

    Directory of Open Access Journals (Sweden)

    Galashov Nikolay

    2016-01-01

    Full Text Available The object of the study are boilers that burn organic fuel and the recovery boilers (RB of the combined cycle plant (CCP, which are al-so working on the products of the combustion of hydrocarbon fuels. The purpose of research is to find technologies that increase efficiency of the thermal power plant (TPP and technologies that reduce the environmental impact on the environment by burning fossil fuels. The paper deals with the technology of the boilers burning hydrocarbon fuel with condensation of water vapor from the exhaust flue gases. Considered the problems caused by using of this technology. Research shows that the main problem of this technology in the boilers is the lack of reliable methods of calculation of heat exchangers, condensers. Particular attention is paid to the application of this technology in the recovery boilers combined-cycle plants, which are currently gaining increasing use in the generation of electricity from the combustion of gas in power plants. It is shown that the application of technology of condensation of water vapor in RB CCP, the temperature decreases of exhaust gases from 100 to 40 °С, allows increasing the effi-ciency of the RB with 86.2 % to 99.5 %, i.e. at 12.3 %, and increase the ef-ficiency of the CCP at 2.8 %.

  9. Thermal–hydraulic calculation and analysis of a 600 MW supercritical circulating fluidized bed boiler with annular furnace

    International Nuclear Information System (INIS)

    Wang, Long; Yang, Dong; Shen, Zhi; Mao, Kaiyuan; Long, Jun

    2016-01-01

    Highlights: • Non-linear model of supercritical CFB boiler with annular furnace is developed. • Many empirical correlations are used to solve the model. • The thermal–hydraulic characteristics of boiler are analyzed. • The results show that the design of the annular furnace is reasonable. - Abstract: The development of supercritical Circulating Fluidized Bed (CFB) boiler has great economic and environmental value. An entirely new annular furnace structure with outer and inner ring sidewalls for supercritical CFB boiler has been put forward by Institute of Engineering Thermophysics (IET), Chinese Academy of Sciences and Dongfang Boiler Group Co., Ltd. (DBC). Its outer and inner ring furnace structure makes more water walls arranged and reduces furnace height availably. In addition, compared with other additional evaporating heating surface structures such as mid-partition and water-cooled panels, the integrative structure can effectively avoid the bed-inventory overturn and improve the penetrability of secondary air. The conditions of the 600 MW supercritical CFB boiler including capability, pressure and mass flux are harsh. In order to insure the safety of boiler operation, it is very necessary to analyze the thermal–hydraulic characteristics of water-wall system. The water-wall system with complicated pipe arrangement is regarded as a network consisting of series-parallel circuits, pressure nodes and linking circuits, which represent vertical water-wall tubes, different headers and linking tubes, respectively. Based on the mass, momentum and energy conservation, a mathematical model is built, which consists of some simultaneous nonlinear equations. The mass flux in circuits, pressure drop between headers, outer vapor temperature of water-wall system and metal temperature data of tubes at the boiler maximum continuous rating (BMCR), 75% BMCR and 30% BMCR loads are obtained by solving the mathematical model. The results show that the vertical water

  10. Decision making model for the recovery of useful material resources from wastes

    International Nuclear Information System (INIS)

    Rising, K.H.; Jensen, G.A.; FitzPatrick, V.F.

    1982-06-01

    In the United States, many of the material resources necessary for energy production are imported. Strategic stockpiling of these resources has been a well-known method for reducing the economic and productivity impact of supply interruption in case of emergency. Another viable option is the recovery of valuable materials and recycle of useful products from wastes generated in energy production and industrial processing. The technical feasibility for recovery and recycle, including decontamination of nuclear-related materials, has been proven and demonstrated. The economic feasibility would depend on both the resale and strategic values of the material, the saving from reusing rather than disposing of the material, the reclamation cost, and other factors that may influence the incentive for recovery and recycle. The purpose of the work presented in this paper is to develop a model to identify the economic and other incentives for the reclamation of useful material resources. Using available data to quantify factors such as strategic and resale values, reclamation cost and disposal cost saving, this model calculates the incentive value consisting of the above factors and selects the appropriate reclamation option. Because this model is empirical, there are limitations to its application. However, within the boundary where the model has been tested, it can be a useful tool for the decision maker to evaluate the economic feasibility of reclamation

  11. An extended model for ultrasonic-based enhanced oil recovery with experimental validation.

    Science.gov (United States)

    Mohsin, Mohammed; Meribout, Mahmoud

    2015-03-01

    This paper suggests a new ultrasonic-based enhanced oil recovery (EOR) model for application in oil field reservoirs. The model is modular and consists of an acoustic module and a heat transfer module, where the heat distribution is updated when the temperature rise exceeds 1 °C. The model also considers the main EOR parameters which includes both the geophysical (i.e., porosity, permeability, temperature rise, and fluid viscosity) and acoustical (e.g., acoustic penetration and pressure distribution in various fluids and mediums) properties of the wells. Extended experiments were performed using powerful ultrasonic waves which were applied for different kind of oils & oil saturated core samples. The corresponding results showed a good matching with those obtained from simulations, validating the suggested model to some extent. Hence, a good recovery rate of around 88.2% of original oil in place (OOIP) was obtained after 30 min of continuous generation of ultrasonic waves. This leads to consider the ultrasonic-based EOR as another tangible solution for EOR. This claim is supported further by considering several injection wells where the simulation results indicate that with four (4) injection wells; the recovery rate may increase up-to 96.7% of OOIP. This leads to claim the high potential of ultrasonic-based EOR as compared to the conventional methods. Following this study, the paper also proposes a large scale ultrasonic-based EOR hardware system for installation in oil fields. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Hypospadias surgery in children: improved service model of enhanced recovery pathway and dedicated surgical team.

    Science.gov (United States)

    Wong, Y S; Pang, K K; Tam, Y H

    2018-05-21

    Children in Hong Kong are generally hospitalised for 1 to 2 weeks after hypospadias repairs. In July 2013, we introduced a new service model that featured an enhanced recovery pathway and a dedicated surgical team responsible for all perioperative services. In this study, we investigated the outcomes of hypospadias repair after the introduction of the new service model. We conducted a retrospective study on consecutive children who underwent primary hypospadias repair from January 2006 to August 2016, comparing patients under the old service with those under the new service. Outcome measures included early morbidity, operative success, and completion of enhanced recovery pathway. The old service and new service cohorts comprised 176 and 126 cases, respectively. There was no difference between the two cohorts in types of hypospadias and surgical procedures performed. The median hospital stay was 2 days in the new service cohort compared with 10 days in the old service cohort (Pservice than the old service. Multivariable analysis revealed that the new service significantly reduced the odds of early morbidity (odds ratio=0.35, 95% confidence interval=0.15-0.85; P=0.02) and operative failure (odds ratio=0.32, 95% confidence interval=0.17-0.59; Pservice. Of the new service cohort, 111(88.1%) patients successfully completed the enhanced recovery pathway. The enhanced recovery pathway can be implemented safely and effectively to primary hypospadias repair. A dedicated surgical team may play an important role in successful implementation of the enhanced recovery pathway and optimisation of surgical outcomes.

  13. Vagus nerve stimulation delivered during motor rehabilitation improves recovery in a rat model of stroke.

    Science.gov (United States)

    Khodaparast, Navid; Hays, Seth A; Sloan, Andrew M; Fayyaz, Tabbassum; Hulsey, Daniel R; Rennaker, Robert L; Kilgard, Michael P

    2014-09-01

    Neural plasticity is widely believed to support functional recovery following brain damage. Vagus nerve stimulation paired with different forelimb movements causes long-lasting map plasticity in rat primary motor cortex that is specific to the paired movement. We tested the hypothesis that repeatedly pairing vagus nerve stimulation with upper forelimb movements would improve recovery of motor function in a rat model of stroke. Rats were separated into 3 groups: vagus nerve stimulation during rehabilitation (rehab), vagus nerve stimulation after rehab, and rehab alone. Animals underwent 4 training stages: shaping (motor skill learning), prelesion training, postlesion training, and therapeutic training. Rats were given a unilateral ischemic lesion within motor cortex and implanted with a left vagus nerve cuff. Animals were allowed 1 week of recovery before postlesion baseline training. During the therapeutic training stage, rats received vagus nerve stimulation paired with each successful trial. All 17 trained rats demonstrated significant contralateral forelimb impairment when performing a bradykinesia assessment task. Forelimb function was recovered completely to prelesion levels when vagus nerve stimulation was delivered during rehab training. Alternatively, intensive rehab training alone (without stimulation) failed to restore function to prelesion levels. Delivering the same amount of stimulation after rehab training did not yield improvements compared with rehab alone. These results demonstrate that vagus nerve stimulation repeatedly paired with successful forelimb movements can improve recovery after motor cortex ischemia and may be a viable option for stroke rehabilitation. © The Author(s) 2014.

  14. Project recovers free wasted energy from an OSB dryer while eliminating a hog boiler

    Energy Technology Data Exchange (ETDEWEB)

    Normandin, A.; Levesque, S.; Laflamme, Y.; Charron, R. [Mesar-Environair Inc., Quebec, PQ (Canada)

    2008-09-15

    This article described how a mill producing oriented strand board (OSB) in Quebec optimized its energy balance with the installation of a flue gas heat recovery (FGHR) system developed by Mesar-Environair Inc. Many OSB mills produce enough wood waste heat to supply their hog boilers with valuable, yet inexpensive, fuel. The objective of this project was to recover waste heat and to find an application in the milling process to re-valorize it. The plant was using 3 hog boilers to heat thermal oil for their process, but only the newest hog boiler was in compliance for particulate emissions levels. The solution involved the use of a direct contact heat exchanger to meet the mill's requirements. The process consisted of pumping the log pond water in a counter-current direction to the humid OSB dryer flue gas. The energy was transferred from the gas to the water via vapor condensation. The customized equipment recovered most of the wasted heat and transferred it to the plant's log ponds. Cool process water from the log ponds was then recirculated through the condenser to trap the wasted energy. The efficiency of the main hog boiler and the chip dry was about 80 per cent. The FGHR process was designed to recover 85 per cent of the wasted energy that was directed to the atmosphere. The heat recovery unit can typically generate temperatures of 70 to 80 degrees C. In addition to fewer emissions of carbon dioxide and nitrogen oxides going out the stack, the FGHR system offers the advantages of heating the process water without additional fuel, and shutting down an old hog boiler. 1 tabs., 3 figs.

  15. Elucidating the role of recovery experiences in the job demands-resources model.

    Science.gov (United States)

    Moreno-Jiménez, Bernardo; Rodríguez-Muñoz, Alfredo; Sanz-Vergel, Ana Isabel; Garrosa, Eva

    2012-07-01

    Based on the Job Demands-Resources (JD-R) model, the current study examined the moderating role of recovery experiences (i.e., psychological detachment from work, relaxation, mastery experiences, and control over leisure time) on the relationship between one job demand (i.e., role conflict) and work- and health-related outcomes. Results from our sample of 990 employees from Spain showed that psychological detachment from work and relaxation buffered the negative impact of role conflict on some of the proposed outcomes. Contrary to our expectations, we did not find significant results for mastery and control regarding moderating effects. Overall, findings suggest a differential pattern of the recovery experiences in the health impairment process proposed by the JD-R model.

  16. Improving boiler unit performance using an optimum robust minimum-order observer

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Hamed; Bakhtiari-Nejad, Firooz [Energy and Control Centre of Excellence, Department of Mechanical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2011-03-15

    To achieve a good performance of the utility boiler, dynamic variables such as drum pressure, steam temperature and water level of drum must be controlled. In this paper, a linear time invariant (LTI) model of a boiler system is considered in which the input variables are feed-water and fuel mass rates. Due to the inaccessibility of some state variables of boiler system, a minimum-order observer is designed based on Luenberger's model to gain an estimate state x of the true state x. Low cost of design and high accuracy of states estimation are the main advantages of the minimum-order observer; in comparison with previous designed full-order observers. By applying the observer on the closed-loop system, a regulator system is designed. Using an optimal functional code developed in MATLAB environment, desired observer poles are found such that suitable time response specifications of the boiler system are achieved and the gain and phase margin values are adjusted in an acceptable range. However, the real dynamic model may associate with parametric uncertainties. In that case, optimum region of poles of observer-based controller are found such that the robust performance of the boiler system against model uncertainties is guaranteed. (author)

  17. Orion Boiler Plate Airdrop Test System

    Science.gov (United States)

    Machin, Ricardo A.; Evans, Carol T.

    2013-01-01

    On the 29th of February 2012 the Orion Capsule Parachute Assembly System (CPAS) project attempted to perform an airdrop test of a boilerplate test article for the second time. The first attempt (Cluster Development Test 2, July 2008) to deliver a similar boilerplate from a C-17 using the Low Velocity Air Drop (LVAD) technique resulted in the programmer parachute failing to properly inflate, the test article failing to achieve the desired test initiation conditions, and the test article a total loss. This paper will pick up where the CDT-2 failure investigation left off, describing the test technique that was adopted, and outline the modeling that was performed to gain confidence that the second attempt would be successful. The second boiler plate test (Cluster Development Test 3-3) was indeed a complete success and has subsequently been repeated several times, allowing the CPAS project to proceed with the full scale system level development testing required to integrate the hardware to the first Entry Flight Test vehicle as well as go into the Critical Design Review with minimum risk and a mature design.

  18. Computations of NOx emissions of domestic boilers

    Energy Technology Data Exchange (ETDEWEB)

    Thevenin, D. [Ecole Centrale de Paris, 92 - Chatenay-Malabry (France). EM2C Lab.; Gicquel, O.; Darabiha, N.

    2001-07-01

    Due to severe regulations concerning pollutant emissions, practical devices using combustion to release energy must be designed from the start using accurate, predictive numerical tools. A partially premixed methane/air flame in a two-dimensional configuration is investigated in this work. This configuration is close to those used in real domestic gas boilers. The flame structure and flow pattern are calculated using complex chemistry and detailed transport models. A post-processing method is then used to predict NO emission. Computations are performed for two configurations. The two cases have the same primary and secondary mass flow-rates and equivalence ratio. The only difference between them is the introduction of an insert inside the primary injector. Both results have been compared to measurements. Calculations are found to be in good agreement with the flame shapes observed experimentally. The classical burner shows a Bunsen-type flame while the one with an insert has a totally different shape (butterfly-type flame). NO emission levels are also well predicted in both configurations. The butterfly flame induces a reduction in NO emission. This reduction seems to be due to the increased mixing between the burnt gases and the secondary air jet, which homogenizes the temperature distribution and reduces the maximum temperature. (orig.)

  19. A comparison of two coaching approaches to enhance implementation of a recovery-oriented service model.

    Science.gov (United States)

    Deane, Frank P; Andresen, Retta; Crowe, Trevor P; Oades, Lindsay G; Ciarrochi, Joseph; Williams, Virginia

    2014-09-01

    Moving to recovery-oriented service provision in mental health may entail retraining existing staff, as well as training new staff. This represents a substantial burden on organisations, particularly since transfer of training into practice is often poor. Follow-up supervision and/or coaching have been found to improve the implementation and sustainment of new approaches. We compared the effect of two coaching conditions, skills-based and transformational coaching, on the implementation of a recovery-oriented model following training. Training followed by coaching led to significant sustained improvements in the quality of care planning in accordance with the new model over the 12-month study period. No interaction effect was observed between the two conditions. However, post hoc analyses suggest that transformational coaching warrants further exploration. The results support the provision of supervision in the form of coaching in the implementation of a recovery-oriented service model, and suggest the need to better elucidate the mechanisms within different coaching approaches that might contribute to improved care.

  20. Boiler house modernization through shared savings program

    Energy Technology Data Exchange (ETDEWEB)

    Breault, R.W. [Tecogen, Waltham, MA (United States)

    1995-12-31

    Throughout Poland as well as the rest of Eastern Europe, communities and industries rely on small heat only boilers to provide district and process heat. Together these two sectors produce about 85,000 MW from boilers in the 2 to 35 MW size range. The bulk of these units were installed prior to 1992 and must be completely overhauled to meet the emission regulations which will be coming into effect on January 1, 1998. Since the only practical fuel is coal in most cases, these boilers must be either retrofit with emission control technology or be replaced entirely. The question that arises is how to accomplish this given the current tight control of capital in Poland and other East European countries. A solution that we have for this problem is shared savings. These boilers are typically operating with a quiet low efficiency as compared to western standards and with excessive manual labor. Installing modernization equipment to improve the efficiency and to automate the process provides savings. ECOGY provides the funds for the modernization to improve the efficiency, add automation and install emission control equipment. The savings that are generated during the operation of the modernized boiler system are split between the client company and ECOGY for a number of years and then the system is turned over in entirety to the client. Depending on the operating capacity, the shared savings agreement will usually span 6 to 10 years.

  1. The load structure of electro boilers

    International Nuclear Information System (INIS)

    Feilberg, N.; Livik, K.

    1995-01-01

    Load measurements have been performed on 24 electro boilers with a time resolution of one hour throughout a period of one year. The boilers are used for space heating and heating of tap water in office buildings, shopping centres and apartment buildings. All boilers have tariffs with disconnection agreements. This report presents load analyses of the measurements from each boiler, and typical load profiles are calculated and presented. It also analyses how boilers are used in relation to the outdoor temperature and the power price on the spot market. All the measurements are performed in Bergen, Norway, in the period August 1993 - August 1994. Typical load profiles are shown, both annual and daily, as well as specific load parameters in addition to key figures used in calculating the total power load on the distribution network. The climate impact on energy and power load is evaluated. The report also shows examples of how the results may be applied in various special fields. 8 figs., 9 tabs

  2. Increasing the efficiency of the condensing boiler

    Science.gov (United States)

    Zaytsev, ON; Lapina, EA

    2017-11-01

    Analysis of existing designs of boilers with low power consumption showed that the low efficiency of the latter is due to the fact that they work in most cases when the heating period in the power range is significantly less than the nominal power. At the same time, condensing boilers do not work in the most optimal mode (in condensing mode) in the central part of Russia, a significant part of their total operating time during the heating season. This is due to existing methods of equipment selection and joint operation with heating systems with quantitative control of the coolant. It was also revealed that for the efficient operation of the heating system, it is necessary to reduce the inertia of the heat generating equipment. Theoretical patterns of thermal processes in the furnace during combustion gas at different radiating surfaces location schemes considering the influence of the very furnace configuration, characterized in that to reduce the work condensing boiler in conventional gas boiler operation is necessary to maintain a higher temperature in the furnace (in the part where spiral heat exchangers are disposed), which is possible when redistributing heat flow - increase the proportion of radiant heat from the secondary burner emitter allow Perey For the operation of the condensing boiler in the design (condensation) mode practically the entire heating period.

  3. Ultrasonic boiler inspection and economic analysis guidelines

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    Boiler tube failures cause approximately 6% availability loss of large fossil-fired power generating plants. This loss can be reduced by systematic approaches using ultrasonic examination and root cause failure analysis methods. Two projects sponsored by EPRI have provided utility engineers with guidelines for performing ultrasonic examinations and with details on 22 types of tube failure mechanisms. A manual has been published that provides descriptions of typical locations, superficial appearances, damage mechanisms, metallurgy, microstructural changes, likely root causes, and potential corrective actions. Application of the principles in the manual is being demonstrated in an EPRI-funded project at 10 electric utilities over the next two years. Guidelines have been published that prescribe the activities necessary for ultrasonic examinations of boiler tubes. Eight essential elements of a boiler examination should be performed to assure that possible economic benefits are obtained. Work was supported by EPRI under RP 1890 and RP 1865. A software package has been developed for effectively planning inspections for wall thinning in fossil-fired boiler tubing. The software assists in minimizing costs associated with maintenance, such as inspection and repair, while the life of the boiler is maximized

  4. Moisture transfer through the membrane of a cross-flow energy recovery ventilator: Measurement and simple data-driven modeling

    Science.gov (United States)

    CR Boardman; Samuel V. Glass

    2015-01-01

    The moisture transfer effectiveness (or latent effectiveness) of a cross-flow, membrane based energy recovery ventilator is measured and modeled. Analysis of in situ measurements for a full year shows that energy recovery ventilator latent effectiveness increases with increasing average relative humidity and surprisingly increases with decreasing average temperature. A...

  5. Modeling and Control of a Parallel Waste Heat Recovery System for Euro-VI Heavy-Duty Diesel Engines

    NARCIS (Netherlands)

    Feru, E.; Willems, F.P.T.; Jager, B. de; Steinbuch, M.

    2014-01-01

    This paper presents the modeling and control of a waste heat recovery system for a Euro-VI heavy-duty truck engine. The considered waste heat recovery system consists of two parallel evaporators with expander and pumps mechanically coupled to the engine crankshaft. Compared to previous work, the

  6. Modeling and control of a parallel waste heat recovery system for Euro-VI heavy-duty diesel engines

    NARCIS (Netherlands)

    Feru, E.; Willems, F.P.T.; Jager, de A.G.; Steinbuch, M.

    2014-01-01

    This paper presents the modeling and control of a waste heat recovery systemfor a Euro-VI heavy-duty truck engine. The considered waste heat recovery system consists of two parallel evaporators with expander and pumps mechanically coupled to the engine crankshaft. Compared to previous work, the

  7. Multi-view 3D human pose estimation combining single-frame recovery, temporal integration and model adaptation

    NARCIS (Netherlands)

    Hofmann, K.M.; Gavrilla, D.M.

    2009-01-01

    We present a system for the estimation of unconstrained 3D human upper body movement from multiple cameras. Its main novelty lies in the integration of three components: single frame pose recovery, temporal integration and model adaptation. Single frame pose recovery consists of a hypothesis

  8. Using CFD to investigate heater fouling in a utility boiler

    International Nuclear Information System (INIS)

    Pang, L.; Sun, B.; Salcudean, M.

    2004-01-01

    A simulation investigation into the combustion and heat transfer process in a utility boiler is presented. The work is based on the commercial software Fluent 6.1.18. Flow, chemistry, energy, conservation and radiation models are used to simulate the process inside the furnace. Radiation and convection models are considered in the horizontal heater. The temperature and velocity fields are calculated to unveil the process inside and outside the furnace. The result shows that the fouling in reheater is formed because of the temperature and velocity field in the flue gas passage. A limited test is done to validate the simulation. (author)

  9. Analytical evaluation of energy efficiency potential enhancement of heat-generating units by flow variation in the boiler circuit

    Directory of Open Access Journals (Sweden)

    Artamonov Pavel A.

    2017-01-01

    Full Text Available Three-dimensional models of the most common boiler schemes are developed and the hydraulic characteristic of each scheme is built. The calculation results of the main technical and economic indicators of the schemes are done. They are energy, metal consumption, capital costs and operating costs. According to the results of the analysis, there is a technical solution to reduce the energy consumption of the boiler circuit pumping equipment. The complex evaluation of the options in the context of the boiler manufacturer and operation is made, the investment attractiveness is calculated.

  10. 46 CFR 52.25-5 - Miniature boilers (modifies PMB-1 through PMB-21).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Miniature boilers (modifies PMB-1 through PMB-21). 52.25... ENGINEERING POWER BOILERS Other Boiler Types § 52.25-5 Miniature boilers (modifies PMB-1 through PMB-21). Miniature boilers must meet the applicable provisions in this part for the boiler type involved and the...

  11. Robust H(infinity) tracking control of boiler-turbine systems.

    Science.gov (United States)

    Wu, J; Nguang, S K; Shen, J; Liu, G; Li, Y G

    2010-07-01

    In this paper, the problem of designing a fuzzy H(infinity) state feedback tracking control of a boiler-turbine is solved. First, the Takagi and Sugeno fuzzy model is used to model a boiler-turbine system. Next, based on the Takagi and Sugeno fuzzy model, sufficient conditions for the existence of a fuzzy H(infinity) nonlinear state feedback tracking control are derived in terms of linear matrix inequalities. The advantage of the proposed tracking control design is that it does not involve feedback linearization technique and complicated adaptive scheme. An industrial boiler-turbine system is used to illustrate the effectiveness of the proposed design as compared with a linearized approach. 2010 ISA. Published by Elsevier Ltd. All rights reserved.

  12. Advanced technique for computing fuel combustion properties in pulverized-fuel fired boilers

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, V.R. (Vsesoyuznyi Teplotekhnicheskii Institut (Russian Federation))

    1992-03-01

    Reviews foreign technical reports on advanced techniques for computing fuel combustion properties in pulverized-fuel fired boilers and analyzes a technique developed by Combustion Engineering, Inc. (USA). Characteristics of 25 fuel types, including 19 grades of coal, are listed along with a diagram of an installation with a drop tube furnace. Characteristics include burn-out intensity curves obtained using thermogravimetric analysis for high-volatile bituminous, semi-bituminous and coking coal. The patented LFP-SKM mathematical model is used to model combustion of a particular fuel under given conditions. The model allows for fuel particle size, air surplus, load, flame height, and portion of air supplied as tertiary blast. Good agreement between computational and experimental data was observed. The method is employed in designing new boilers as well as converting operating boilers to alternative types of fuel. 3 refs.

  13. Evaluation of thermal overload in boiler operators.

    Science.gov (United States)

    Braga, Camila Soares; Rodrigues, Valéria Antônia Justino; Campos, Julio César Costa; de Souza, Amaury Paulo; Minette, Luciano José; de Moraes, Angêlo Casali; Sensato, Guilherme Luciano

    2012-01-01

    The Brazilians educational institutions need a large energy demand for the operation of laundries, restaurants and accommodation of students. Much of that energy comes from steam generated in boilers with wood fuel. The laboral activity in boiler may present problems for the operator's health due to exposure to excessive heat, and its operation has a high degree of risk. This paper describes an analysis made the conditions of thermal environment in the operation of a B category boiler, located at a Higher Education Institution, located in the Zona da Mata Mineira The equipments used to collect data were Meter WBGT of the Heat Index; Meter of Wet Bulb Index and Globe Thermometer (WBGT); Politeste Instruments, an anemometer and an Infrared Thermometer. By the application of questionnaires, the second phase consisted of collecting data on environmental factors (temperature natural environment, globe temperature, relative humidity and air velocity). The study concluded that during the period evaluated, the activity had thermal overload.

  14. Development of infill drilling recovery models for carbonates reservoirs using neural networks and multivariate statistical as a novel method

    International Nuclear Information System (INIS)

    Soto, R; Wu, Ch. H; Bubela, A M

    1999-01-01

    This work introduces a novel methodology to improve reservoir characterization models. In this methodology we integrated multivariate statistical analyses, and neural network models for forecasting the infill drilling ultimate oil recovery from reservoirs in San Andres and Clearfork carbonate formations in west Texas. Development of the oil recovery forecast models help us to understand the relative importance of dominant reservoir characteristics and operational variables, reproduce recoveries for units included in the database, forecast recoveries for possible new units in similar geological setting, and make operational (infill drilling) decisions. The variety of applications demands the creation of multiple recovery forecast models. We have developed intelligent software (Soto, 1998), oilfield intelligence (01), as an engineering tool to improve the characterization of oil and gas reservoirs. 01 integrates neural networks and multivariate statistical analysis. It is composed of five main subsystems: data input, preprocessing, architecture design, graphic design, and inference engine modules. One of the challenges in this research was to identify the dominant and the optimum number of independent variables. The variables include porosity, permeability, water saturation, depth, area, net thickness, gross thickness, formation volume factor, pressure, viscosity, API gravity, number of wells in initial water flooding, number of wells for primary recovery, number of infill wells over the initial water flooding, PRUR, IWUR, and IDUR. Multivariate principal component analysis is used to identify the dominant and the optimum number of independent variables. We compared the results from neural network models with the non-parametric approach. The advantage of the non-parametric regression is that it is easy to use. The disadvantage is that it retains a large variance of forecast results for a particular data set. We also used neural network concepts to develop recovery

  15. Decoupled numerical simulation of a solid fuel fired retort boiler

    International Nuclear Information System (INIS)

    Ryfa, Arkadiusz; Buczynski, Rafal; Chabinski, Michal; Szlek, Andrzej; Bialecki, Ryszard A.

    2014-01-01

    The paper deals with numerical simulation of the retort boiler fired with solid fuel. Such constructions are very popular for heating systems and their development is mostly based on the designer experience. The simulations have been done in ANSYS/Fluent package and involved two numerical models. The former deals with a fixed-bed combustion of the solid fuel and free-board gas combustion. Solid fuel combustion is based on the coal kinetic parameters. This model encompasses chemical reactions, radiative heat transfer and turbulence. Coal properties have been defined with user defined functions. The latter model describes flow of water inside a water jacked that surrounds the combustion chamber and flue gas ducts. The novelty of the proposed approach is separating of the combustion simulation from the water flow. Such approach allows for reducing the number of degrees of freedom and thus lowering the necessary numerical effort. Decoupling combustion from water flow requires defining interface boundary condition. As this boundary condition is unknown it is adjusted iteratively. The results of the numerical simulation have been successfully validated against measurement data. - Highlights: • New decoupled modelling of small scale boiler is proposed. • Fixed-bed combustion model based on kinetic parameters is introduced. • Decoupling reduced the complexity of the model and computational time. • Simple and computationally inexpensive coupling algorithm is proposed. • Model is successfully validated against measurements

  16. Application of ELD and load forecast in optimal operation of industrial boiler plants equipped with thermal stores

    International Nuclear Information System (INIS)

    Cao Jiacong

    2007-01-01

    Optimal operation of industrial boiler plants with objects of high energy efficiency and low fuel cost is still well worth investigating when energy problem becomes a world's concern, for there are a great number of boiler plants serving industries. The optimization of operation is a measure that is less expensive and easier to carry out than many other measures. Economic load dispatch (ELD) is an effective approach to optimal operation of industrial boiler plants. In the paper a newly developed method referred to as the method of minimum-departure model (MDM) is used in the ELD for boiler plants. It is more convenient for carrying out ELD when boiler plants are equipped with thermal energy stores that usually adopt the working mode of optimal segmentation of a daily load curve. In the case of industrial boiler plants, ELD needs a prerequisite, viz., the accurate load forecast, which is performed using artificial neural networks in this paper. A computer program for the optimal operation was completed and applied to an example, which results the minimum daily fuel cost of the whole boiler plant

  17. Reactive Transport Modeling of Microbe-mediated Fe (II) Oxidation for Enhanced Oil Recovery

    Science.gov (United States)

    Surasani, V.; Li, L.

    2011-12-01

    Microbially Enhanced Oil Recovery (MEOR) aims to improve the recovery of entrapped heavy oil in depleted reservoirs using microbe-based technology. Reservoir ecosystems often contain diverse microbial communities those can interact with subsurface fluids and minerals through a network of nutrients and energy fluxes. Microbe-mediated reactions products include gases, biosurfactants, biopolymers those can alter the properties of oil and interfacial interactions between oil, brine, and rocks. In addition, the produced biomass and mineral precipitates can change the reservoir permeability profile and increase sweeping efficiency. Under subsurface conditions, the injection of nitrate and Fe (II) as the electron acceptor and donor allows bacteria to grow. The reaction products include minerals such as Fe(OH)3 and nitrogen containing gases. These reaction products can have large impact on oil and reservoir properties and can enhance the recovery of trapped oil. This work aims to understand the Fe(II) oxidation by nitrate under conditions relevant to MEOR. Reactive transport modeling is used to simulate the fluid flow, transport, and reactions involved in this process. Here we developed a complex reactive network for microbial mediated nitrate-dependent Fe (II) oxidation that involves both thermodynamic controlled aqueous reactions and kinetic controlled Fe (II) mineral reaction. Reactive transport modeling is used to understand and quantify the coupling between flow, transport, and reaction processes. Our results identify key parameter controls those are important for the alteration of permeability profile under field conditions.

  18. A simplified time-dependent recovery model as applied to RCP seal LOCAs

    International Nuclear Information System (INIS)

    Kohut, P.; Bozoki, G.; Fitzpatrick, R.

    1991-01-01

    In Westinghouse-designed reactors, the reactor coolant pump (RCP) seals constantly require a modest amount of cooling. This cooling function depends on the service water (SW) system. Upon the loss of the cooling function due to the unavailability of the SW, component cooling water system or electrical power (station blackout), the RCP seals may degrade, resulting in a loss-of-coolant accident (LOCA). Recent studies indicate that the frequency of the loss of SW initiating events is higher than previously thought. This change significantly increases the core damage frequency contribution from RCP seal failure. The most critical/dominant element in the loss of SW events was found to be the SW-induced RCP seal failure. For these potential accident scenarios, there are large uncertainties regarding the actual frequency of RCP seal LOCA, the resulting leakage rate, and time-dependent behavior. The roles of various recovery options based on the time evolution of the seal LOCA have been identified and taken into account in recent NUREG-1150 probabilistic risk assessment PRA analyses. In this paper, a consistent time-dependent recovery model is described that takes into account the effects of various recovery actions based on explicit considerations given to a spectrum of time- and flow-rate dependencies. The model represents a simplified approach but is especially useful when extensive seal leak rate and core uncovery information is unavailable

  19. Recovery of acidified mountain lakes in Norway as predicted by the MAGIC model

    Directory of Open Access Journals (Sweden)

    Bernard J. COSBY

    2004-02-01

    Full Text Available As part of the EU project EMERGE the biogeochemical model MAGIC was used to reconstruct acidification history and predict future recovery for mountain lakes in two regions of Norway. Central Norway (19 lakes receives low levels of acid deposition, most of the lakes have undergone only minor amounts of acidification, and all are predicted to recover in the future. Central Norway thus represents a reference area for more polluted regions in southern Norway and elsewhere in Europe. Southern Norway (23 lakes, on the other hand, receives higher levels of acid deposition, nearly all the studied lakes were acidified and had lost fish populations, and although some recovery has occurred during the period 1980-2000 and additional recovery is predicted for the next decades, the model simulations indicated that the majority of the lakes will not achieve water quality sufficient to support trout populations. Uncertainties in these predictions include possible future N saturation and the exacerbating effects of climate change. The mountain lakes of southern Norway are among the most sensitive in Europe. For southern Norway additional measures such as stricter controls of emissions of air pollutants will be required to obtain satisfactory water quality in the future.

  20. Modeling of Recovery Profiles in Mentally Disabled and Intact Patients after Sevoflurane Anesthesia; A Pharmacodynamic Analysis

    Science.gov (United States)

    Shin, Teo Jeon; Noh, Gyu-Jeong; Koo, Yong-Seo

    2014-01-01

    Purpose Mentally disabled patients show different recovery profiles compared to normal patients after general anesthesia. However, the relationship of dose-recovery profiles of mentally disabled patients has never been compared to that of normal patients. Materials and Methods Twenty patients (10 mentally disabled patients and 10 mentally intact patients) scheduled to dental surgery under general anesthesia was recruited. Sevoflurane was administered to maintain anesthesia during dental treatment. At the end of the surgery, sevoflurane was discontinued. End-tidal sevoflurane and recovery of consciousness (ROC) were recorded after sevoflurane discontinuation. The pharmacodynamic relation between the probability of ROC and end-tidal sevoflurane concentration was analyzed using NONMEM software (version VII). Results End-tidal sevoflurane concentration associated with 50% probability of ROC (C50) and γ value were lower in the mentally disabled patients (C50=0.37 vol %, γ=16.5 in mentally intact patients, C50=0.19 vol %, γ=4.58 in mentally disabled patients). Mentality was a significant covariate of C50 for ROC and γ value to pharmacodynamic model. Conclusion A sigmoid Emanx model explains the pharmacodynamic relationship between end-tidal sevoflurane concentration and ROC. Mentally disabled patients may recover slower from anesthesia at lower sevoflurane concentration at ROC an compared to normal patients. PMID:25323901

  1. Modelling a recovery network for WEEE: a case study in Portugal.

    Science.gov (United States)

    Gomes, Maria Isabel; Barbosa-Povoa, Ana Paula; Novais, Augusto Q

    2011-07-01

    The European Union directive for electric and electronic waste, published in 2003, enforced all European countries to meet some targets concerning the recycling and recovery of these products. This directive was transposed to the Portuguese legislation in 2004. Following this, a group of EEE producers set up an organization (Amb3e) whose mission was to design and manage a nationwide recovery network for WEEE, which will be the subject matter of this work. A generic MILP model is proposed to represent this network, which is applied to its design and planning, where the best locations for collection and sorting centres are chosen simultaneously with the definition of a tactical network planning. Several analyses are performed to provide further insights regarding the selection of these alternative locations. The results gave support to the company strategic expansion plans for a high number of centres to be opened and to their location near the major WEEE sources. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. The Train Driver Recovery Problem - a Set Partitioning Based Model and Solution Method

    DEFF Research Database (Denmark)

    Rezanova, Natalia Jurjevna; Ryan, David

    2010-01-01

    The need to recover a train driver schedule occurs during major disruptions in the daily railway operations. Based on data from the Danish passenger railway operator DSB S-tog A/S, a solution method to the train driver recovery problem (TDRP) is developed. The TDRP is formulated as a set...... branching strategy using the depth-first search of the Branch & Bound tree. The LP relaxation of the TDRP possesses strong integer properties. We present test scenarios generated from the historical real-life operations data of DSB S-tog A/S. The numerical results show that all but one tested instances...... partitioning problem. We define a disruption neighbourhood by identifying a small set of drivers and train tasks directly affected by the disruption. Based on the disruption neighbourhood, the TDRP model is formed and solved. If the TDRP solution provides a feasible recovery for the drivers within...

  3. Calculating the consequences of recovery, a European model for inhabited areas

    DEFF Research Database (Denmark)

    Charnock, T.W.; Jones, J.A.; Singer, L.N.

    2009-01-01

    The European Model for Inhabited Areas (ERMIN) was developed to allow a user to explore different recovery options following the contamination of an urban environment with radioactive material and to refine an appropriate strategy for the whole region affected. The input data include a description......, the contamination on urban surfaces, the activity concentration in air from resuspension, the doses to workers undertaking the recovery work, the quantity and activity of waste generated and the cost and work required to implement the countermeasure. ERMIN has been designed to be implemented as a tool that supports...... the approach of decision-makers and allows the area to be broken down into smaller regions where different conditions prevail and different countermeasure packages are enacted....

  4. The early operation of the helical once-through boilers at Heysham 1 and Hartlepool

    International Nuclear Information System (INIS)

    Mathews, A.J.

    1988-01-01

    The Heysham 1 and Hartlepool AGR Reactors are equipped with 'pod' boilers set into the walls of the Pre-stressed Concrete Pressure Vessel. Each Reactor unit has eight pod boilers, which are of a somewhat unique single pressure, once through, helically wound type incorporating a reheater. The pods are provided with a limited amount of strain gauge and thermocouple instrumentation concentrated mainly in two specially instrumented boilers at each site. During Commissioning prior to power raising, extensive noise and vibration tests utilising the special attain gauge instrumented boilers, gave encouraging results. This has led to an increase in coolant gas mass flow of 5% above the design level. Following power raising in 1983 and 1984, detailed boiler performance testing, mainly using the special thermocouple instrumented boilers, showed that the actual behaviour differed from the computer design predictions. A major temperature tilt existed across the boiler tubes resulting in higher than predicted temperatures in the outer radius rows of tubes and the reverse situation in the inner tubes. The effect differed in magnitude between Hartlepool Reactor 1 and the other three Reactors probably due to construction differences. As a result output was initially limited to approximately 58% of design (380 MW (Generated)). A major programme of altering the flow control ferrules was carried out during the first statutory overhauls in 1985 and 1986. The initial results from Heysham 1 were not very encouraging (a gain of 70 MW(e)) but further computer model correlations led to revised patterns in Heysham and Hartlepool Reactor 2 which have since yielded improvements in output potential of up to 200 MW(e). The paper discusses the commissioning test results described above and describes the details of the extensive work carried out to achieve higher output. (author)

  5. Development of combined low-emissions burner devices for low-power boilers

    Science.gov (United States)

    Roslyakov, P. V.; Proskurin, Yu. V.; Khokhlov, D. A.

    2017-08-01

    Low-power water boilers are widely used for autonomous heat supply in various industries. Firetube and water-tube boilers of domestic and foreign manufacturers are widely represented on the Russian market. However, even Russian boilers are supplied with licensed foreign burner devices, which reduce their competitiveness and complicate operating conditions. A task of developing efficient domestic low-emissions burner devices for low-power boilers is quite acute. A characteristic property of ignition and fuel combustion in such boilers is their flowing in constrained conditions due to small dimensions of combustion chambers and flame tubes. These processes differ significantly from those in open combustion chambers of high-duty power boilers, and they have not been sufficiently studied yet. The goals of this paper are studying the processes of ignition and combustion of gaseous and liquid fuels, heat and mass transfer and NO x emissions in constrained conditions, and the development of a modern combined low-emissions 2.2 MW burner device that provides efficient fuel combustion. A burner device computer model is developed and numerical studies of its operation on different types of fuel in a working load range from 40 to 100% of the nominal are carried out. The main features of ignition and combustion of gaseous and liquid fuels in constrained conditions of the flame tube at nominal and decreased loads are determined, which differ fundamentally from the similar processes in steam boiler furnaces. The influence of the burner devices design and operating conditions on the fuel underburning and NO x formation is determined. Based on the results of the design studies, a design of the new combined low-emissions burner device is proposed, which has several advantages over the prototype.

  6. 46 CFR 61.05-20 - Boiler safety valves.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Boiler safety valves. 61.05-20 Section 61.05-20 Shipping... INSPECTIONS Tests and Inspections of Boilers § 61.05-20 Boiler safety valves. Each safety valve for a drum, superheater, or reheater of a boiler shall be tested at the interval specified by table 61.05-10. [CGD 95-028...

  7. Application of GPRS and GIS in Boiler Remote Monitoring System

    OpenAIRE

    Hongchao Wang; Yifeng Wu

    2012-01-01

    Application of GPRS and GIS in boiler remote monitoring system was designed in this paper by combining the advantage of GPRS and GIS in remote data transmission with configuration monitoring technology. The detail information of the operating conditions of the industrial boiler can be viewed by marking the location of boiler on the electronic map dynamically which can realize the unified management for industrial boiler of a region or city conveniently. Experimental application show that the ...

  8. Slagging and fouling evaluation of PC-fired boilers using AshPro{sup SM}

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Zhanhua; Iman, Felicia; Lu, Pisi [SmartBurn, LLC, Madison, WI (United States)

    2013-07-01

    SmartBurn {sup registered} applied AshPro{sup SM} model to two 512 MW Tangential-fired (T-fired) boilers firing US western sub- bituminous coals to evaluate the boiler slagging behaviors with different operating conditions and OFA. The boiler convective pass fouling behaviors with three different coals were also evaluated. The slagging evaluation results indicate that the OFA configuration and air flow distribution have dramatically impacts on the ash impaction rates and slagging patterns on the furnace walls. Deposit growth and strength vary at the different regions of the furnace walls. The fouling evaluation reveals that the tube bank configuration, the amount of incoming ash, the profiles of flue gas temperature, velocity, and species all have significant impacts on fouling deposit formation, growth, and strength development. In addition, the varying ash particle sizes and chemical compositions from different coals also play important roles on the fouling deposit strength development and removal. The investigation demonstrated that AshPro{sup SM} model can be used to evaluate localized slagging and fouling problems that are related to specific boiler configuration and operating conditions. It can be used to identify the major causes of ash deposition and can guide changes in boiler operation.

  9. Developing trends with boiler operation and management

    Energy Technology Data Exchange (ETDEWEB)

    Stark, J.M. [Occupational Safety and Health Service, Wellington (New Zealand). Dept. of Labour, Engineering Safety Branch

    1993-12-31

    Over recent years there have been many improvements in boiler control and safety management systems. Technology has made major advances and is now regarded as being well proven in Australia, Europe and the United Kingdom and these changes have been examined by a project committee, convened for the purpose, to establish whether they are equally applicable in New Zealand. The result of the committee`s findings and experience is contained in the `Draft Code of Practice`. This paper explains the development of the `Code of Practice`, the reasoning behind some of the decisions taken and the implications of these changes to boiler owners.

  10. Optimal load allocation of multiple fuel boilers.

    Science.gov (United States)

    Dunn, Alex C; Du, Yan Yi

    2009-04-01

    This paper presents a new methodology for optimally allocating a set of multiple industrial boilers that each simultaneously consumes multiple fuel types. Unlike recent similar approaches in the utility industry that use soft computing techniques, this approach is based on a second-order gradient search method that is easy to implement without any specialized optimization software. The algorithm converges rapidly and the application yields significant savings benefits, up to 3% of the overall operating cost of industrial boiler systems in the examples given and potentially higher in other cases, depending on the plant circumstances. Given today's energy prices, this can yield significant savings benefits to manufacturers that raise steam for plant operations.

  11. Firewood boiler operators and heat exposure

    Directory of Open Access Journals (Sweden)

    Vilson Bernardo Stollmeier

    2017-12-01

    Full Text Available This article presents an analysis of heat exposure work in boiler industry wood from a company in the industrial sector, focusing on the analysis of the environmental burden of the activity. Therefore, the methodological procedures consisted of document analysis, interviews, filming, evaluation problems of the effects of the hot environment and its prevention. The results show that the fuel to the boiler operators are exposed to heat and need guidance on their daily activities with prevention of diseases affected by excessive heat. Are also suggested training in technical and health to improve working conditions and the operator's health.

  12. Boiler inspection manipulator for Torness Power Station

    International Nuclear Information System (INIS)

    Carrey, R.T.A.; Yule, I.Y.; Sibson, S.; Playle, M.J.

    1996-01-01

    The Advanced Gas-cooled Reactors at Torness and Heysham 2 are provided with dedicated access for remote inspection equipment. These in-service inspection (ISI) accesses comprise 12 penetrations above the core for inspection of the above core area and boilers, 12 below core penetrations for inspection of the lower boiler area and access through any of the 8 gas circulator penetrations for inspection of the sub-diagrid area. This paper describes a manipulator which will access the reactor from above the core via any of the 8 peripheral penetrations. (UK)

  13. TA-2 Water Boiler Reactor Decommissioning Project

    International Nuclear Information System (INIS)

    Durbin, M.E.; Montoya, G.M.

    1991-06-01

    This final report addresses the Phase 2 decommissioning of the Water Boiler Reactor, biological shield, other components within the biological shield, and piping pits in the floor of the reactor building. External structures and underground piping associated with the gaseous effluent (stack) line from Technical Area 2 (TA-2) Water Boiler Reactor were removed in 1985--1986 as Phase 1 of reactor decommissioning. The cost of Phase 2 was approximately $623K. The decommissioning operation produced 173 m 3 of low-level solid radioactive waste and 35 m 3 of mixed waste. 15 refs., 25 figs., 3 tabs

  14. Fault detection-case: modelling of temperature control of smelt in a chemical recovery; Deteccao de defeitos via redes neurais: aplicacao no sistema de resfriamento das bicas de fundidos de uma caldeira de recuperacao

    Energy Technology Data Exchange (ETDEWEB)

    Martinelli, Sergio H.S. [Universidade Estadual de Maringa, PR (Brazil); Klabin Papeis Monte Alegre, Telemaco Borba, PR (Brazil); Neitzel, Ivo [Faculdade de Telemaco Borba, PR (Brazil); Universidade Estadual de Maringa, PR (Brazil); Vieira, Osvaldo [Universidade Estadual de Maringa, PR (Brazil); Klabin Papeis Monte Alegre, Telemaco Borba, PR (Brazil)

    2008-07-01

    This paper proposes a method for the detection of defects in the control systems components which was applied in the smelt spouts cooling system of a chemical recovery boiler. The almost static behavior of the system was modeled with neural networks. The comparison between the inferred variable by the model and the measurement in the process generated a residual vector. A second neural network, the classification type, was built to analyze the residue. The training process of this neural network was carried out with two types of data base, one of them where there was no defect (classified as non faulty data) and the other where there were defects in one of the process control system sensors. The generation of faulty data was carried out through defects simulation by neural model. Both neural networks were programmed on Excel software to make the continuous monitoring of the productive process possible. The process data feeding in the system was done though the Plant Information (PI) software. The rate of false alarm of process monitoring for two and half months was of 3%. Errors ranging from 2 to 15% were simulated at the manipulated variable of the control system to test the performance of the method. Within the range of 10% simulated errors the detection of defects rate was of 97% for the set of non trained standards. (author)

  15. 46 CFR 56.50-30 - Boiler feed piping.

    Science.gov (United States)

    2010-10-01

    ... 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) General... least two separate means of supplying feed water for the boilers. All feed pumps shall be fitted with...

  16. Biomass boiler conversion potential in the eastern United States

    Science.gov (United States)

    Charles D. Ray; Li Ma; Thomas Wilson; Daniel Wilson; Lew McCreery; Janice K. Wiedenbeck

    2013-01-01

    The U.S. is the world's leading consumer of primary energy. A large fraction of this energy is used in boiler installations to generate steam and hot water for heating applications. It is estimated there are total 163,000 industrial and commercial boilers in use in the United States of all sizes. This paper characterizes the commercial and industrial boilers in...

  17. New materials for boilers in USC power plants

    International Nuclear Information System (INIS)

    Hong, Sung Ho; Hong, Seok Joo

    2003-01-01

    The efficiency of boiler in fossil power plants is a strong function of steam temperature and pressure. Thus, the main technology of increasing boiler efficiency is the development of stronger high temperature materials, capable of operating under high stresses at ever increasing temperature. This paper will presents the new material relating to boiler of USC power plant

  18. 46 CFR 176.812 - Pressure vessels and boilers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Pressure vessels and boilers. 176.812 Section 176.812... TONS) INSPECTION AND CERTIFICATION Material Inspections § 176.812 Pressure vessels and boilers. (a.... (b) Periodic inspection and testing requirements for boilers are contained in § 61.05 in subchapter F...

  19. 46 CFR 115.812 - Pressure vessels and boilers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Pressure vessels and boilers. 115.812 Section 115.812... CERTIFICATION Material Inspections § 115.812 Pressure vessels and boilers. (a) Pressure vessels must be tested... testing requirements for boilers are contained in § 61.05 in subchapter F of this chapter. [CGD 85-080, 61...

  20. 46 CFR 109.205 - Inspection of boilers and machinery.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Inspection of boilers and machinery. 109.205 Section 109... OPERATIONS Tests, Drills, and Inspections § 109.205 Inspection of boilers and machinery. The chief engineer or engineer in charge, before he assumes charge of the boilers and machinery of a unit shall inspect...

  1. 40 CFR 63.988 - Incinerators, boilers, and process heaters.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Incinerators, boilers, and process... Routing to a Fuel Gas System or a Process § 63.988 Incinerators, boilers, and process heaters. (a) Equipment and operating requirements. (1) Owners or operators using incinerators, boilers, or process...

  2. Aspects of new material application for boilers construction

    International Nuclear Information System (INIS)

    Czerniawski, R.

    1996-01-01

    Review of steel types commonly used for energetic boilers construction has been done. The worldwide trends in new materials application for improvement of boilers quality have been discussed. The mechanical properties of boiler construction steels have been shown and compared. 3 refs, 5 figs, 1 tab

  3. Lower price for solar boilers must improve market penetration

    International Nuclear Information System (INIS)

    Koevoet, J.B.J.

    1999-01-01

    The Dutch government aims at 1.7 PJ thermal energy for the year 2007 to be supplied by solar water heaters. For that target the number of installed solar boilers must increase seven times the number of installed solar boilers in 1998. This can be stimulated by a considerable reduction of the market price for such boilers

  4. 10 CFR 431.82 - Definitions concerning commercial packaged boilers.

    Science.gov (United States)

    2010-01-01

    ... gases. Manufacturer of a commercial packaged boiler means any person who manufactures, produces... 10 Energy 3 2010-01-01 2010-01-01 false Definitions concerning commercial packaged boilers. 431.82... COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Packaged Boilers § 431.82 Definitions concerning commercial...

  5. 40 CFR 761.71 - High efficiency boilers.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false High efficiency boilers. 761.71... PROHIBITIONS Storage and Disposal § 761.71 High efficiency boilers. (a) To burn mineral oil dielectric fluid containing a PCB concentration of ≥50 ppm, but boiler shall comply with the following...

  6. 49 CFR 230.36 - Hydrostatic testing of boilers.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Hydrostatic testing of boilers. 230.36 Section 230... Appurtenances Pressure Testing of Boilers § 230.36 Hydrostatic testing of boilers. (a) Time of test. The... to any hydrostatic pressure. Hydrostatic testing required by these rules shall be conducted at 25...

  7. Improved Dynamic Modeling of the Cascade Distillation Subsystem and Integration with Models of Other Water Recovery Subsystems

    Science.gov (United States)

    Perry, Bruce; Anderson, Molly

    2015-01-01

    The Cascade Distillation Subsystem (CDS) is a rotary multistage distiller being developed to serve as the primary processor for wastewater recovery during long-duration space missions. The CDS could be integrated with a system similar to the International Space Station (ISS) Water Processor Assembly (WPA) to form a complete Water Recovery System (WRS) for future missions. Independent chemical process simulations with varying levels of detail have previously been developed using Aspen Custom Modeler (ACM) to aid in the analysis of the CDS and several WPA components. The existing CDS simulation could not model behavior during thermal startup and lacked detailed analysis of several key internal processes, including heat transfer between stages. The first part of this paper describes modifications to the ACM model of the CDS that improve its capabilities and the accuracy of its predictions. Notably, the modified version of the model can accurately predict behavior during thermal startup for both NaCl solution and pretreated urine feeds. The model is used to predict how changing operating parameters and design features of the CDS affects its performance, and conclusions from these predictions are discussed. The second part of this paper describes the integration of the modified CDS model and the existing WPA component models into a single WRS model. The integrated model is used to demonstrate the effects that changes to one component can have on the dynamic behavior of the system as a whole.

  8. A mathematical model to predict the effect of heat recovery on the wastewater temperature in sewers.

    Science.gov (United States)

    Dürrenmatt, David J; Wanner, Oskar

    2014-01-01

    Raw wastewater contains considerable amounts of energy that can be recovered by means of a heat pump and a heat exchanger installed in the sewer. The technique is well established, and there are approximately 50 facilities in Switzerland, many of which have been successfully using this technique for years. The planning of new facilities requires predictions of the effect of heat recovery on the wastewater temperature in the sewer because altered wastewater temperatures may cause problems for the biological processes used in wastewater treatment plants and receiving waters. A mathematical model is presented that calculates the discharge in a sewer conduit and the spatial profiles and dynamics of the temperature in the wastewater, sewer headspace, pipe, and surrounding soil. The model was implemented in the simulation program TEMPEST and was used to evaluate measured time series of discharge and temperatures. It was found that the model adequately reproduces the measured data and that the temperature and thermal conductivity of the soil and the distance between the sewer pipe and undisturbed soil are the most sensitive model parameters. The temporary storage of heat in the pipe wall and the exchange of heat between wastewater and the pipe wall are the most important processes for heat transfer. The model can be used as a tool to determine the optimal site for heat recovery and the maximal amount of extractable heat. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Improving boiler unit performance using an optimum robust minimum-order observer

    International Nuclear Information System (INIS)

    Moradi, Hamed; Bakhtiari-Nejad, Firooz

    2011-01-01

    Research highlights: → Multivariable model of a boiler unit with uncertainty. → Design of a robust minimum-order observer. → Developing an optimal functional code in MATLAB environment. → Finding optimum region of observer-based controller poles. → Guarantee of robust performance in the presence of parametric uncertainties. - Abstract: To achieve a good performance of the utility boiler, dynamic variables such as drum pressure, steam temperature and water level of drum must be controlled. In this paper, a linear time invariant (LTI) model of a boiler system is considered in which the input variables are feed-water and fuel mass rates. Due to the inaccessibility of some state variables of boiler system, a minimum-order observer is designed based on Luenberger's model to gain an estimate state x-tilde of the true state x. Low cost of design and high accuracy of states estimation are the main advantages of the minimum-order observer; in comparison with previous designed full-order observers. By applying the observer on the closed-loop system, a regulator system is designed. Using an optimal functional code developed in MATLAB environment, desired observer poles are found such that suitable time response specifications of the boiler system are achieved and the gain and phase margin values are adjusted in an acceptable range. However, the real dynamic model may associate with parametric uncertainties. In that case, optimum region of poles of observer-based controller are found such that the robust performance of the boiler system against model uncertainties is guaranteed.

  10. Backstepping-based nonlinear adaptive control for coal-fired utility boiler-turbine units

    International Nuclear Information System (INIS)

    Fang, Fang; Wei, Le

    2011-01-01

    The control system of boiler-turbine unit plays an important role in improving efficiency and reducing emissions of power generation unit. The nonlinear, coupling and uncertainty of the unit caused by varying working conditions should be fully considered during the control system design. This paper presents an efficient control scheme based on backstepping theory for improving load adaptability of boiler-turbines in wide operation range. The design process of the scheme includes model preprocessing, control Lyapunov functions selection, interlaced computation of adaptive control laws, etc. For simplification and accuracy, differential of steam pipe inlet pressure and integral terms of target errors are adopted. Also, to enhance practicality, implementation steps of the scheme are proposed. A practical nonlinear model of a 500 MW coal-fired boiler-turbine unit is used to test the efficiency of the proposed scheme in different conditions.

  11. Experimental verification of the scaling laws for CFB boilers of different designs

    Directory of Open Access Journals (Sweden)

    Mirek Paweł

    2016-06-01

    Full Text Available In the paper flow dynamic similarity criteria have been presented to reflect the macroscopic flow pattern in the combustion chamber of large-scale circulating fluidised bed boilers. The proposed scaling rules have been verified on two cold models of CFB boilers operating in Tauron Wytwarzanie S.A. - El. Lagisza division (scale factor 1/20 and Fortum Power and Heat Poland Sp. z o. o. Czestochowa division (scale factor 1/10 – working with the power of 966 MWth and 120 MWth, respectively. As follows from the results of measurements, regardless of CFB boiler’s geometry the use of a defined set of criterial numbers allows to obtain satisfactory agreement between the suspension density distributions registered in the CFB boilers and scaling models.

  12. Concentration-driven models revisited: towards a unified framework to model settling tanks in water resource recovery facilities

    OpenAIRE

    Torfs, Elena; Marti, M. Carmen; Locatelli, Florent; Balemans, Sophie; Burger, Raimund; Diehl, Stefan; Laurent, Julien; Vanrolleghem, Peter A.; Francois, Pierre; Nopens, Ingmar

    2017-01-01

    A new perspective on the modelling of settling behaviour in water resource recovery facilities is introduced. The ultimate goal is to describe in a unified way the processes taking place both in primary settling tanks (PSTs) and secondary settling tanks (SSTs) for a more detailed operation and control. First, experimental evidence is provided, pointing out distributed particle properties (such as size, shape, density, porosity, and flocculation state) as an important common source of distribu...

  13. A freshwater food web model for the combined effects of nutrients and insecticide stress and subsequent recovery

    NARCIS (Netherlands)

    Traas, T.P.; Janse, J.H.; Brink, van den P.J.; Brock, T.C.M.; Aldenberg, T.

    2004-01-01

    A microcosm experiment that addressed the interaction between eutrophication processes and contaminants was analyzed using a food web model. Both direct and indirect effects of nutrient additions and a single insecticide application (chlorpyrifos) on biomass dynamics and recovery of functional

  14. Computational modelling of an Organic Rankine Cycle (ORC waste heat recovery system for an aircraft engine

    Directory of Open Access Journals (Sweden)

    Saadon S.

    2018-01-01

    Full Text Available Escalating fuel prices and carbon dioxide emission are causing new interest in methods to increase the thrust force of an aircraft engine with limitation of fuel consumption. One viable means is the conversion of exhaust engine waste heat to a more useful form of energy or to be used in the aircraft environmental system. A one-dimensional analysis method has been proposed for the organic Rankine cycle (ORC waste heat recovery system for turbofan engine in this paper. The paper contains two main parts: validation of the numerical model and a performance prediction of turbofan engine integrated to an ORC system. The cycle is compared with industrial waste heat recovery system from Hangzhou Chinen Steam Turbine Power CO., Ltd. The results show that thrust specific fuel consumption (TSFC of the turbofan engine reach lowest value at 0.91 lbm/lbf.h for 7000 lbf of thrust force. When the system installation weight is applied, the system results in a 2.0% reduction in fuel burn. Hence implementation of ORC system for waste heat recovery to an aircraft engine can bring a great potential to the aviation industry.

  15. Optimization of Boiler Heat Load in Water-Heating Boiler-House

    Directory of Open Access Journals (Sweden)

    B. A. Bayrashevsky

    2009-01-01

    Full Text Available An analytical method for optimization of water-heating boiler loads has been developed on the basis of approximated semi-empirical dependences pertaining to changes of boiler gross efficiency due to its load. A complex (∂tух/∂ξΔξ is determined on the basis of a systematic analysis (monitoring of experimental data and the Y. P. Pecker’s formula for calculation of balance losses q2. This complex makes it possible to set a corresponding correction to a standard value of the boiler gross efficiency due to contamination of heating surfaces.Software means for optimization of water-heating boilers has been developed and it is recommended to be applied under operational conditions.

  16. Observer-Based Fuel Control Using Oxygen Measurement. A study based on a first-principles model of a pulverized coal fired Benson Boiler

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Palle; Bendtsen, Jan Dimon; Mortensen, Jan Henrik; Just Nielsen, Rene; Soendergaard Pedersen, Tom [Aalborg Univ. (Denmark). Dept. of Control Engineering

    2005-01-01

    This report describes an attempt to improve the existing control of coal mills used at the Danish power plant Nordjyllandsvaerket Unit 3. The coal mills pulverize raw coal to a fine-grained powder, which is injected into the furnace of the power plant. In the furnace the coal is combusted, producing heat, which is used for steam production. With better control of the coal mills, the power plant can be controlled more efficiently during load changes, thus improving the overall availability and efficiency of the plant. One of the main difficulties from a control point of view is that the coal mills are not equipped with sensors that detect how much coal is injected into the furnace. During the project, a fairly detailed, non-linear differential equation model of the furnace and the steam circuit was constructed and validated against data obtained at the plant. It was observed that this model was able to capture most of the important dynamics found in the data. Based on this model, it is possible to extract linearized models in various operating points. The report discusses this approach and illustrates how the model can be linearized and reduced to a lower-order linear model that is valid in the vicinity of an operating point by removing states that have little influence on the overall response. A viable adaptive control strategy would then be to design controllers for each of these simplified linear models, i.e., the control loop that sets references to the coal mills and feedwater, and use the load as a separate input to the control. The control gains should then be scheduled according to the load. However, the variations and uncertainties in the coal mill are not addressed directly in this approach. Another control approach was taken in this project, where a Kalman filter based on measurements of air flow blown into the furnace and the oxygen concentration in the flue gas is designed to estimate the actual coal flow injected into the furnace. With this estimate

  17. Dynamic simulation of a biomass domestic boiler under thermally thick considerations

    NARCIS (Netherlands)

    Gómez, M. A.; Porteiro, J.; De la Cuesta de Cal, Daniel; Patiño, D.; Míguez, J. L.

    2017-01-01

    A biomass combustion model with a thermally thick approach is presented and applied to the simulation of a commercial biomass domestic boiler. A subgrid scale model is used to divide the particles into several grid points, each representing one of the different combustion stages. These grid points

  18. Investigation of fuel lean reburning process in a 1.5 MW boiler

    International Nuclear Information System (INIS)

    Kim, Hak Young; Baek, Seung Wook; Kim, Se Won

    2012-01-01

    Highlights: → We examine a detailed study of fuel lean reburning process in a 1.5 MW gas-fired boiler. → Experimental and numerical researches are conducted. → We investigate change in the level of NO X and CO emission. → The recirculation flow is important in the fuel lean reburning process. -- Abstract: This paper examines a detailed study of fuel lean reburning process applied to a 1.5 MW gas-fired boiler. Experimental and numerical studies were carried out to investigate the effect of the fuel lean reburning process on the NO X reduction and CO emission. Natural gas (CH 4 ) was used as the reburn as well as the main fuel. The amount of the reburn fuel, injection location and thermal load of boiler were considered as experimental parameters. The flue gas data revealed that the fuel lean reburning process led to NO X reduction up to 43%, while CO emission was limited to less than 30 ppm for the 100% thermal load condition. The commercial computational fluid dynamics code FLUENT 6.3, which included turbulence, chemical reaction, radiation and NO modeling, was used to predict the fluid flow and heat transfer characteristics under various operational conditions in the boiler. Subsequently, predicted results were validated with available measured data such as gas temperature distributions and local mean NO X concentrations. The detailed numerical results showed that the recirculation flow developed inside the boiler was found to play an important role in improving the effectiveness of fuel lean reburning process.

  19. Fire-Side Corrosion: A Case Study of Failed Tubes of a Fossil Fuel Boiler

    Directory of Open Access Journals (Sweden)

    Majid Asnavandi

    2017-01-01

    Full Text Available The failures of superheater and reheater boiler tubes operating in a power plant utilizing natural gas or mazut as a fuel have been analysed and the fire-side corrosion has been suggested as the main reason for the failure in boiler tubes. The tubes have been provided by a fossil fuel power plant in Iran and optical and electron microscopy investigations have been performed on the tubes as well as the corrosion products on their surfaces. The results showed that the thickness of the failed tubes is not uniform which suggests that fire-side corrosion has happened on the tubes. Fire-side corrosion is caused by the reaction of combustion products with oxide layers on the tube surface resulting in metal loss and consequently tubes fracture. However, the tubes corrosion behaviour did not follow the conventional models of the fire-side corrosion. Given that, using the corrosion monitoring techniques for these boiler tubes seems essential. As a result, the thickness of the boiler tubes in different parts of the boiler has been recorded and critical points are selected accordingly. Such critical points are selected for installation of corrosion monitoring probes.

  20. Web service availability-impact of error recovery and traffic model

    International Nuclear Information System (INIS)

    Martinello, Magnos; Kaa-hat niche, Mohamed; Kanoun, Karama

    2005-01-01

    Internet is often used for transaction based applications such as online banking, stock trading and shopping, where the service interruption or outages are unacceptable. Therefore, it is important for designers of such applications to analyze how hardware, software and performance related failures affect the quality of service delivered to the users. This paper presents analytical models for evaluating the service availability of web cluster architectures. A composite performance and availability modeling approach is defined considering various causes of service unavailability. In particular, web cluster systems are modeled taking into account: two error recovery strategies (client transparent and non-client-transparent) as well as two traffic models (Poisson and modulated Poisson). Sensitivity analysis results are presented to show their impact on the web service availability. The obtained results provide useful guidelines to web designers

  1. Modeling and Simulation of Membrane-Based Dehumidification and Energy Recovery Process

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhiming [ORNL; Abdelaziz, Omar [ORNL; Qu, Ming [ORNL

    2017-01-01

    This paper introduces a first-order physics-based model that accounts for the fundamental heat and mass transfer between a humid-air vapor stream on feed side to another flow stream on permeate side. The model comprises a few optional submodels for membrane mass transport; and it adopts a segment-by-segment method for discretizing heat and mass transfer governing equations for flow streams on feed and permeate sides. The model is able to simulate both dehumidifiers and energy recovery ventilators in parallel-flow, cross-flow, and counter-flow configurations. The predicted tresults are compared reasonably well with the measurements. The open-source codes are written in C++. The model and open-source codes are expected to become a fundament tool for the analysis of membrane-based dehumidification in the future.

  2. CONSTRUCTIVE MODELLING FOR ZONE OF RECOVERY ENERGY DISTRIBUTION OF DC TRACTION

    Directory of Open Access Journals (Sweden)

    V. I. Shynkarenko

    2016-10-01

    Full Text Available Purpose.The article is aimed to develop the means and methods of forming a plurality of real and potential structural diagrams for zones of energy recovery and different locations of trains for further training neuro-fuzzy networks on the basis of expert solutions and also for the formation of good control. Methodology. Methodology of mathematical and algorithmic constructivism for modeling the structural diagrams of the electric supply system and modes of traction power consumption and the train’s locations in zones of energy recovery was applied. This approach involves the development of constructive-synthesizing structures (CSS with transformation by specialization, interpretation, specification and implementation. Development CSS provides an extensible definition media, relations and the signature of operations and constructive axiomatic. The most complex and essential part of the axioms is the set formed by the substitution rules defining the process of withdrawal of the corresponding structures. Findings. A specialized and specified CSS, which allows considering all the possibilities and features, that supply power traction systems with modern equipment, stations and trains location was designed. Its feature: the semantic content of the terminal alphabet images of electrical traction network and power consumers with relevant attributes. A special case of the formation of the structural diagram shows the possibilities CSS in relation to this problem. Originality. A new approach to solving the problem of rational use of energy recovery, which consists in application of the methods and means of artificial neural networks, expert systems, fuzzy logic and mathematical and algorithmic constructivism. This paper presents the methods of constructive simulation of a production-distribution of energy recovery zone structure in the system of the DC traction. Practical value. The tasks decision of the rational use of energy recovery can

  3. ENVIRONMENTAL ASPECTS OF MODERNIZATION OF HIGH POWER WATER-HEATING BOILERS

    Directory of Open Access Journals (Sweden)

    P. M. Glamazdin

    2016-01-01

    Full Text Available Boilers of KVGM and PTVM series are characterized by high values of NOx and CO content in the combustion products. Reduction of NOx and CO content can be achieved by two ways: by installing the condensing heat recovery unit at the boiler outlet and by improving the heat and mass transfer processes in boiler furnaces. Application of the condensing heat recovery units causes pollution of resulting condensate by low-concentration acids. The authors conducted a study in order to determine the effectiveness of the previously applied methods of suppressing the emission of nitrogen oxides in the boilers of these types. Equalization of the temperature field and, consequently, enhancement of heat transfer in the furnace by substitution the used burners by the more advanced ones, the design of which facilitates reduction the emission of nitrogen oxides, were applied to all the upgraded facilities. The studies fulfilled demonstrate that a reduction of NOx emissions in water-heating high power boilers is fairly possible by means of modernization of the latter. The authors have developed the project of the PTVM-30 boiler modernization, which was implemented at a large boiler plant in the city of Vinnitsa (Ukraine. The project included a number of technical solutions. Six burners were replaced by the two ones that were located in the hearth; also the hearth screen was dismantled. At the same time, reducing the total surface area of the heating caused by the exclusion of hearth screen was compensated by filling the locations of the six embrasures of staff burners on the side screens with straightened furnace tubes. Installing the burners separate from the screen made it possible to eliminate the transfer of vibration to the furnace tubes, and – via them – to the boilers setting. Automation provided “associated regulations”. Draught machines were equipped with frequency regulators. During commissioning of the boiler the studies were carried out that

  4. The recovery paradigm - a model of hope and change for alcohol and drug addiction.

    Science.gov (United States)

    Best, David W; Lubman, Dan I

    2012-08-01

    Alcohol and drug disorders remain major health and social problems in Australia, contributing enormously to the global burden of disease and the everyday practice of primary care. A recent growth in recovery research and recovery focused policies are starting to have an impact in Australia, with implications for how we attempt to resolve these problems. In this article we discuss recent international findings in recovery research, and explore their implications for primary care. Research indicates that over half of dependent substance users will eventually achieve stable recovery. Key predictors of recovery are active engagement in the community and immersion in peer support groups and activities. Recovery requires a twin track approach: enabling and supporting individual recovery journeys, while creating environmental conditions that enable and support a 'social contagion' of recovery, in which recovery is transmitted through supportive social networks and dedicated recovery groups, such as mutual aid.

  5. Selecting Actuator Configuration for a Benson Boiler

    DEFF Research Database (Denmark)

    Kragelund, Martin Nygaard; Leth, John-Josef; Wisniewski, Rafal

    2009-01-01

    with particular focus on a boiler in a power plant operated by DONG Energy - a Danish energy supplier. The problem has been reformulated using mathematic notions from economics. The selection of actuator configuration has been limited to the fuel system which in the considered plant consists of three different...

  6. Environmental control during steam boiler washing

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Marcio A.B.; Abreu Pereira, Vera L. de [Companhia Petroquimica do Nordeste (COPENE), Camacari, BA (Brazil). Div. de Engenharia Ambiental; Ringler, Ulrich E.S. [PROMON Engenharia Ltda., Salvador, BA (Brazil)

    1993-12-31

    The washing and chemical cleaning of boilers, activities of a high polluting potential, are responsible for the generation of wastewater of high contents of heavy metals, suspended solids and chemical oxygen demand (COD). This paper describes the actions carried out by COPENE - Petroquimica do Nordeste S/A - in order to reduce this problem. (author). 10 refs., 3 figs., 2 tabs.

  7. The investigation of the locomotive boiler material

    International Nuclear Information System (INIS)

    Tucholski, Z.; Wasiak, J.; Bilous, W.; Hajewska, E.

    2006-01-01

    In the paper, the history of narrow-gauge railway system is described. The other information about the steam locomotive construction, as well as the technical regulations of its construction and exploitation are also done. The results of the studies of the locomotive boiler material are presented. (authors)

  8. Environmental control during steam boiler washing

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Marcio A.B.; Abreu Pereira, Vera L. de [Companhia Petroquimica do Nordeste (COPENE), Camacari, BA (Brazil). Div. de Engenharia Ambiental; Ringler, Ulrich E.S. [PROMON Engenharia Ltda., Salvador, BA (Brazil)

    1994-12-31

    The washing and chemical cleaning of boilers, activities of a high polluting potential, are responsible for the generation of wastewater of high contents of heavy metals, suspended solids and chemical oxygen demand (COD). This paper describes the actions carried out by COPENE - Petroquimica do Nordeste S/A - in order to reduce this problem. (author). 10 refs., 3 figs., 2 tabs.

  9. Organic carbon recovery modeling for a rotating belt filter and its impact assessment on a plant-wide scale

    DEFF Research Database (Denmark)

    Behera, Chitta Ranjan; Santoro, Domenico; Gernaey, Krist V.

    2018-01-01

    In this study, we perform a systematic plant-wide assessment of the organic carbon recovery concept on wastewater treatment plants by an advanced cellulose recovery enabling technology called rotating belt filter (RBF). To this end, first, an empirical model is developed to describe organic carbon...... recovery by the RBF, which is then used for the plant-wide performance evaluation to further understand the impact of organic carbon recovery by framing four different scenarios. The key features of the scenario analysis are: (i) an RBF operating with thick mat increases methane production (around 10...... %) and brings down aeration energy demand (by 8 %) compared to the primary clarifier (PC) and, (ii) the sludge retention time (SRT) of the activated sludge (AS) tank increases by 55 % when an RBF runs with thick mat and therefore promotes higher nitrification rate, (iii) organic carbon recovery by the RBF does...

  10. Mixture of working fluids in ORC plants with pool boiler evaporator

    International Nuclear Information System (INIS)

    Rajabloo, Talieh; Iora, Paolo; Invernizzi, Costante

    2016-01-01

    Highlights: • We assess the feasibility of pool boiler in ORCs operating with mixture working fluids. • We consider hydrocarbon and siloxane mixtures for low and high temperature ORCs. • Plants with pool boiler show comparable performances to once through evaporator. - Abstract: Power generation using Organic Rankine Cycle was studied in this paper in case of both low and high temperature cycles, exploiting respectively a geothermal heat source available at 167 °C, and heat available at 300 °C from the combustion of biomass. In particular we assess the feasibility of employing mixture of working fluids, in the case of replacing the typical once-through (OT) evaporator with the pool boiler (PB) technology, typically adopted for pure fluids. The analysis evidenced that in general the OT evaporator shows a slightly improved cycle performance in comparison to the PB and it results in some cases advantageous with respect to the pure working fluid. For instance in case of low temperature cycle, the best thermodynamic performances are obtained with mixture of i-C_5 and 75% n-C_4 in case of OT evaporator, yielding a recovery efficiency higher than the case with pure i-C_5 (7.7 vs. 7.4%) given the relatively higher values of both the recovery factor and cycle efficiency. Implementation of PB did not affect the plant performance significantly which shows the feasibility of having PB with potentially easier control.

  11. Development of an end-of-life vehicle recovery model using system dynamics and future research needs

    Science.gov (United States)

    Mohamad-Ali, N.; Ghazilla, R. A. R.; Abdul-Rashid, S. H.; Sakundarini, N.; Ahmad-Yazid, A.; Stephenie, L.

    2017-06-01

    The implementation of end-of-life vehicle (ELV) recovery policy in Malaysia has led vehicle manufacturers to look at different ways to improve design and development of vehicles. Nowadays, it is crucial to incorporate end-of-life (EOL) design strategies into the vehicle design in order to enhance the effectiveness of the ELV recovery network. Although recent studies have shown that product design has a significant effect on the product recovery rate, there is a lack of studies on how EOL design strategies affects the effectiveness of ELV recovery, particularly when there are dynamic changes in the behaviour of the product recovery network. Thus, in this study, we developed a preliminary model based on the system dynamics approach in order to predict the effectiveness of ELV recovery in response to dynamic changes of various factors (including EOL design strategies) in the business environment. We developed this model based on preliminary data that we had gathered from unstructured interviews with the key stakeholders of ELV management in Malaysia. We believe that our model will greatly benefit product designers in incorporating the appropriate EOL design strategies in order to boost ELV recovery effectiveness in Malaysia.

  12. A time-dependent event tree technique for modelling recovery operations

    International Nuclear Information System (INIS)

    Kohut, P.; Fitzpatrick, R.

    1991-01-01

    The development of a simplified time dependent event tree methodology is presented. The technique is especially applicable to describe recovery operations in nuclear reactor accident scenarios initiated by support system failures. The event tree logic is constructed using time dependent top events combined with a damage function that contains information about the final state time behavior of the reactor core. Both the failure and the success states may be utilized for the analysis. The method is illustrated by modeling the loss of service water function with special emphasis on the RCP [reactor coolant pump] seal LOCA [loss of coolant accident] scenario. 5 refs., 2 figs., 2 tabs

  13. Modelling of waste heat recovery for combined heat and power applications

    International Nuclear Information System (INIS)

    Descombes, Georges; Boudigues, Serge

    2009-01-01

    The current environmental context dictates to reduce the pollutant emissions by improving thermal efficiency of the energy production units. The authors present some studies of cogeneration applications using gas turbines and thermal engines. The on-going research concerns a detailed study of thermodynamic modelling cycles with energy recovery. These combined cycles with gas turbine and ICE can generate a potential increase of about 10% of the energy efficiency. They will generate a technological complexity and the over-charge must be estimated. At last, the authors insist on the necessary synergy between gas turbines and thermal engines.

  14. Modeling community integration in workers with delayed recovery from mild traumatic brain injury

    DEFF Research Database (Denmark)

    Mollayeva, T.; Shapiro, C. M.; Mollayeva, S.

    2015-01-01

    Background: Delayed recovery in persons after mild traumatic brain injury (mTBI) is poorly understood. Community integration (CI) is endorsed by persons with neurological disorders as an important outcome. We aimed to describe CI and its associated factors in insured Ontario workers with delayed...... assessments, and insurers' referral files. Community Integration Questionnaire (CIQ) scores were compared using analysis of variance or Spearman's correlation tests. Stepwise multivariable linear regression models were used to evaluate the associations with CI. Results: Ninety-four workers with mTBI (45...

  15. Pandemic recovery analysis using the dynamic inoperability input-output model.

    Science.gov (United States)

    Santos, Joost R; Orsi, Mark J; Bond, Erik J

    2009-12-01

    Economists have long conceptualized and modeled the inherent interdependent relationships among different sectors of the economy. This concept paved the way for input-output modeling, a methodology that accounts for sector interdependencies governing the magnitude and extent of ripple effects due to changes in the economic structure of a region or nation. Recent extensions to input-output modeling have enhanced the model's capabilities to account for the impact of an economic perturbation; two such examples are the inoperability input-output model((1,2)) and the dynamic inoperability input-output model (DIIM).((3)) These models introduced sector inoperability, or the inability to satisfy as-planned production levels, into input-output modeling. While these models provide insights for understanding the impacts of inoperability, there are several aspects of the current formulation that do not account for complexities associated with certain disasters, such as a pandemic. This article proposes further enhancements to the DIIM to account for economic productivity losses resulting primarily from workforce disruptions. A pandemic is a unique disaster because the majority of its direct impacts are workforce related. The article develops a modeling framework to account for workforce inoperability and recovery factors. The proposed workforce-explicit enhancements to the DIIM are demonstrated in a case study to simulate a pandemic scenario in the Commonwealth of Virginia.

  16. Modelling of Evaporator in Waste Heat Recovery System using Finite Volume Method and Fuzzy Technique

    Directory of Open Access Journals (Sweden)

    Jahedul Islam Chowdhury

    2015-12-01

    Full Text Available The evaporator is an important component in the Organic Rankine Cycle (ORC-based Waste Heat Recovery (WHR system since the effective heat transfer of this device reflects on the efficiency of the system. When the WHR system operates under supercritical conditions, the heat transfer mechanism in the evaporator is unpredictable due to the change of thermo-physical properties of the fluid with temperature. Although the conventional finite volume model can successfully capture those changes in the evaporator of the WHR process, the computation time for this method is high. To reduce the computation time, this paper develops a new fuzzy based evaporator model and compares its performance with the finite volume method. The results show that the fuzzy technique can be applied to predict the output of the supercritical evaporator in the waste heat recovery system and can significantly reduce the required computation time. The proposed model, therefore, has the potential to be used in real time control applications.

  17. Promoting recovery via an integrated model of care to deliver a bed-based, mental health prevention and recovery centre.

    Science.gov (United States)

    Lee, Stuart J; Collister, Laura; Stafrace, Simon; Crowther, Elizabeth; Kroschel, Jon; Kulkarni, Jayashri

    2014-10-01

    This research was conducted in order to explore the experience of care and outcomes for people entering a bed-based step-up/step-down Prevention and Recovery Centre (PARC). An audit of files for PARC participants in 2010 collected demographic (age, gender, and marital, housing, employment and education/training status) and clinical measures (length of stay, entry and exit outcome measures, psychiatric hospital use). Participants were also invited to a feedback group to discuss their PARC experience. In 2010, 118 people entered PARC. Most were single and unemployed and 35% were in temporary housing or homeless. In the six months following PARC exit, participants spent significantly less time in psychiatric hospital than in the six months prior to entry (precovery for people with mental illness through promoting independence and illness self-management. © The Royal Australian and New Zealand College of Psychiatrists 2014.

  18. Quality and generation rate of solid residues in the boiler of a waste-to-energy plant.

    Science.gov (United States)

    Allegrini, E; Boldrin, A; Jansson, S; Lundtorp, K; Fruergaard Astrup, T

    2014-04-15

    The Danish waste management system relies significantly on waste-to-energy (WtE) plants. The ash produced at the energy recovery section (boiler ash) is classified as hazardous waste, and is commonly mixed with fly ash and air pollution control residues before disposal. In this study, a detailed characterization of boiler ash from a Danish grate-based mass burn type WtE was performed, to evaluate the potential for improving ash management. Samples were collected at 10 different points along the boiler's convective part, and analysed for grain size distribution, content of inorganic elements, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD and PCDF), and leaching of metals. For all samples, PCDD and PCDF levels were below regulatory limits, while high pH values and leaching of e.g. Cl were critical. No significant differences were found between boiler ash from individual sections of the boiler, in terms of total content and leaching, indicating that separate management of individual ash fractions may not provide significant benefits. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. On-line monitoring system for utility boiler diagnostics

    International Nuclear Information System (INIS)

    Radovanovic, P.M.; Afgan, N.H.; Caralho, M.G.

    1997-01-01

    The paper deals with the new developed modular type Monitoring System for Utility Boiler Diagnostics. Each module is intended to assess the specific process and can be used as a stand alone application. Four modules are developed, namely: LTC - module for the on-line monitoring of parameters related to the life-time consumption of selected boiler components; TRD - module for the tube rupture detection by the position and working fluid Ieakage quantity; FAM - module for the boiler surfaces fouling (slagging) assessment and FLAP - module for visualization of the boiler furnace flame position. All four modules are tested on respective pilot plants built oil the 200 and 300 MWe utility boilers. Monitoring System is commercially available and can be realized in any combination of its modules depending on demands induced by the operational problems of specific boiler. Further development of Monitoring System is performed in accordance with the respective EU project on development of Boiler Expert System. (Author)

  20. The behavior of ash species in suspension fired biomass boilers

    DEFF Research Database (Denmark)

    Jensen, Peter Arendt

    While fluid bed and grate fired boilers initially was the choice of boilers used for power production from both wood and herbaceous biomass, in recent years suspension fired boilers have been increasingly used for biomass based power production. In Denmark several large pulverized fuel boilers have...... been converted from coal to biomass combustion in the last 15 years. This have included co-firing of coal and straw, up to 100% firing of wood or straw andthe use of coal ash as an additive to remedy problems with wood firing. In parallel to the commercialization of the pulverized biomass firing...... technology a long range of research studies have been conducted, to improve our understanding of the influence and behavior of biomass ash species in suspension fired boilers. The fuel ash plays a key role with respect tooptimal boiler operation and influences phenomena’s as boiler chamber deposit formation...