bluuebunny/crossref_metadata_2025 huggingface dataset:
Validating LFG Generation Model With Recovery Rates From Mexican Landfills
Authors: García P. M. , Vega-Galaz J.
Published: February 2014

Landfill gas (LFG) recovery predictions obtained using Mexico Landfill Gas Model 2.0 were compared to LFG recovery rates from the two biggest landfills in Mexico (Mexico City Landfill called “Bordo Poniente” and Monterrey City Landfill “SIMEPRODE”.).

The corresponding landfill characteristics (e.g. leachate levels and handling; use of covers and/or liners, compaction procedures, etc.) where analyzed and considered for the modeling in both cases, resulting in recovery efficiency rates and correction factors for each site.

For Mexico City landfill, a pumping test was performed for a period of 25 days during a bidding process, started by Mexico City Government. 11 extraction wells were installed for the test along with a blower-flare system, with a capacity of 1,000 m3/hr. During the test period, individual well measurements were taken every 4 hours obtaining information such as: gas composition (CH4, CO2 and O2), vacuum pressure and gas temperature. Also a main measurement was taken every 4 hours at the blower-flare system in which obtained the total LFG flow in addition to the above information.

Modeling results for Mexico City landfill show a good accuracy (below the actual recovery rate obtained during the test).

For Monterrey City landfill, the recovery rates were obtained from the historical data from the LFG to energy (LFGTE) project running since 2003 by BENLESA. Only the information between 2009 and 2012 were considered due to the last expansion of the plant to 16 generators, 1.06 MW each. Modeling results for Monterrey City landfill, overestimated the actual LFG recovery for the last 4 years including 2012. The causes for the difference between modeled and actual recovery rates for both landfills were analyzed and recommendations to improve the modeling results and the recovery rates were made.
Assessment of Stabilization Mechanisms of Confined, Turbulent, Lifted Jet Flames: Effects of Ambient Coflow
Authors: Hutchins Andrew R. , Kribs James D. , Muncey Richard D. , Lyons Kevin M.
Published: February 2014

The aim of this investigation is to determine the effects of confinement on the stabilization of turbulent, lifted methane (CH4) jet flames. A confinement cylinder (stainless steel) separates the coflow from the ambient air and restricts excess room air from being entrained into the combustion chamber, and thus produces varying stabilization patterns. The experiments were executed using fully confined, semi-confined, and unconfined conditions, as well as by varying fuel flow rate and coflow velocity (ambient air flowing in the same direction as the fuel jet). Methane flames experience liftoff and blowout at well-known conditions for unconfined jets, however, it was determined that with semi-confined conditions the flame does not experience blowout. Instead of the conventional unconfined stabilization patterns, an intense, intermittent behavior of the flame was observed. This sporadic behavior of the flame, while under semi-confinement, was determined to be a result from the restricted oxidizer access as well as the asymmetrical boundary layer that forms due to the viewing window. While under full confinement the flame behaved in a similar method as while under no confinement (full ambient air access). The stable nature of the flame while fully confined lacked the expected change in leading edge fluctuations that normally occur in turbulent jet flames. These behaviors address the combustion chemistry (lack of oxygen), turbulent mixing, and heat release that combine to produce the observed phenomena.
Evaluation of Biomass and Torrefied Coal Co-Firing in Large Utilities Boilers
Authors: Chudnovsky B. , Steg Z. , Kunin A. , Talanker A. , Sabek A.
Published: February 2014

Renewable energy targets and CO2 emissions markets drive the transition to a cleaner and renewable energy production system. In this manner, utilities are looking for cost effective options with a minimum impact on unit performance and reliability. Co-firing biomass, in comparison with other renewable sources, is the main contributor to meeting the world’s renewable energy target. It avoids the destruction of capital, by making coal-fired power plants cleaner without having to replace them. Biomass co-firing provides a relatively low cost means of increasing renewables capacity and an effective way of taking advantage of the high thermal efficiency of large coal fired boilers. The direct displacement of coal when co-firing plus the higher conversion efficiencies generally achieved also contribute to achieving higher CO2 reduction benefits from each co-fired tone of biomass. However, coal–fired power plants are not designed to co-fire large amounts of biomass. This means that not more than 5–10% of biomass can be co-fired. In order to increase this amount, utilities have to make significant investments in dedicated biomass handling and processing equipment. Even when these investments are made, the co-firing percentage is often limited to 20% thermal fraction, because the chemical and physical properties of bio-fuels. Another possibility, to increase biomass fraction in co-firing is torrefied fuel burning. Co-firing torrefied biomass could increase considerably co-firing percentages, while saving investment and transport cost compared to biomass co-firing. However, it should be concerned regarding the ability of generators involved in coal and biomass co-firing that this alternative may impact on boiler reliability due to specific biomass properties and it this issue should be carefully evaluated during design stage. In order to prevent such an undesirable effect we initiated a study to understand the influence of using co-firing on the capacity, limitations of furnace size, heat transfer surfaces, firing systems, pulverizers, fans, airheaters and equipment for post combustion emission treatment.

This paper discusses the technical and commercial application of coal and biomass/ torrefied coal co-firing in large utility boilers. In the present study we used a series of simulation using computer codes; the latter are CFD codes suitable for simulation of the performance and emissions of co-fired utility boilers and an expert system that aided in issues like boiler and furnace performance, pulverizing capabilities, post combustion treatment equipment performance, sootblowing optimization, boiler Fans operation and performance.
Scale Model Testing Towards Primary Air Optimization of a CFB Boiler
Authors: Hughes Tyler , Kang John , Porter Daniel , Munukutla Sastry , Idem Stephen
Published: February 2014

Primary air flow is supplied to the wind box of a 300 MW CFB boiler by means of three primary air ducts connected to a common plenum. A flow rate measurement is performed in each duct using an Annubar flow meter. Due to the tight configuration of the piping and the associated turbulence, the measured flows in the three ducts were not consistent, resulting in improper air flow distribution in the boiler. A primary air duct flow study was performed in an effort to improve measurement accuracy, which will lead to improved combustion efficiency and low load cycling by allowing precision air flow control in the furnace.

The objective of this project was to employ a 1/10th scale model test to determine the best method to improve the flow upstream of each Annubar flow meter. Tests were conducted with room temperature air at several flow rates generated by a centrifugal fan. Reynolds number independence was achieved in the tests. Appropriate dimensionless Grashof and Prandtl number scaling was used to extrapolate the scale model tests to the high temperature conditions prevalent in the unit. Flow visualization and measurements using a five-hole directional velocity probe were performed. It was determined that mounting 50% open area screens in the primary air duct of the scale model had the effect of significantly reducing both yaw and pitch angles across the Annubar measurement plane. A complimentary benefit was that the velocity profiles in the flow direction were notably flattened by the addition of the screens. Furthermore the performance of the Annubar flow meters could be improved if the measurement plane was moved further upstream of the opposed blade flow control damper.
Basic Cell Geometry for Modeling Flow in Metal Foam
Authors: Suleiman Ahmed S. , Dukhan Nihad
Published: February 2014

Open-cell metal foam is a class of modern porous media that possesses high thermal conductivity, large accessible surface area per unit volume and high porosities (often greater than 90%). The internal structure of the foam is web-like that produces a complex flow field, including turbulence, flow reversal and mixing, when a fluid passes through it. All of these attributes make metal foam a very attractive core for many applications, e.g. heat exchange, filtration and reactors. The rather complex and intrinsically random architecture of the foam is virtually impossible to capture exactly. In this paper, we present a unit cell geometrical model that can be used to study transport inside the foam. In particular, the unit cell is used to study the flow filed and pressure drop inside commercial foam. The Navier-Stokes equations are solved directly and velocity and pressure fields are obtained for various approach velocities using COMSOL. The details of the modeling process are given in this paper. The pressure drop results are compared to the Forchheimer prediction and to experimental data, from which the permeability and form drag coefficient can be calculated. The commercial foam that was used in the experiment had 10 pores per inch, and porosity of 91.2%. Air was forced to flow inside the foam using an open-loop wind tunnel. Good agreement between the modeling and experimental results are obtained, within the velocity range of the study. The results are encouraging and lend confidence to the modeling approach, which paves the way for investigating other phenomena inside the foam, e.g., heat transfer.
Research on Wind Turbine Blade Surface Damage Fault On-Line Monitoring and Diagnosis System
Authors: Feng Yongxin , Yang Tao , Deng Xiaowen , Gao Qingshui , Zhang Chu , Zhang Lei , Chen Gang
Published: February 2014

The basic fault types of wind turbine blades are introduced, a novel blade surface damage detection method based on machine vision is being suggested. The network of wind turbine blade surface damage fault on-line monitoring and fault diagnosis system has already been developed. The system architecture, software modules and functions are described, and given application example illustrates the usefulness and effectiveness of this system. The result shows that this system can monitor the surface damage failure of the blade in real time, and can effectively reduce the blade’s maintenance costs for wind farms, especially offshore wind farm.
Studies of Supercritical Carbon Dioxide Brayton Cycle Performance Coupled to Various Heat Sources
Authors: Ahn Yoonhan , Lee Jekyoung , Kim Seong Gu , Lee Jeong Ik
Published: February 2014

The concern about the global climate change and the unstable supply of fossil fuels stimulate the research of the new energy source utilization and the efficient energy system design. As the interests on the future energy sources and renovating the conventional power plants grow, an efficient and widely applicable power conversion system is required to satisfy both requirements. S-CO2 cycle is considered as a promising candidate with the advantages of 1) relatively high efficiency in the modest temperature (450–750°C) region because of non-ideal properties near the critical point, 2) effectively reduced size of the total cycle with compact turbo-machines and heat exchangers, 3) potential for using in various applications with competitive efficiency and simple layout. The S-CO2 cycle was originally considered as an attractive candidate for the power conversion cycle of the next generation nuclear reactors. However, due to many benefits of the S-CO2 cycle, it is recently considered in other conventional and renewable energy system applications including fossil fuel power plant system, ship propulsion application, concentrated solar power system, fuel cell bottoming power cycle and so on. This paper will discuss about the design of S-CO2 cycle for the various energy system applications over different temperature range. Unlike a large size power plant which usually focuses more on maximizing the cycle efficiency, a small capacity energy system is seriously concerned about the total size of the cycle. In this manner, several preliminary S-CO2 cycle designs will be compared in terms of the efficiency and the physical size. Various layouts and components of S-CO2 cycle are compared to find the optimum cycle for each energy systems. The in-house codes developed by the KAIST research team are used to evaluate the various cycle performances and component preliminary designs. The obtained results will be compared to the conventional power conversion systems along with its implication to other existing designs.
A New Robotic Process for In Situ Heat Treatment on Large Steel Components
Authors: Boudreault Eric , Hazel Bruce , Godin Stéphane , Côté Jean
Published: February 2014

To avoid dismantling very large equipment while ensuring high-quality repair, a new robotic process is developed for local post weld heat treatment in situ.

The temperature around the area repaired is controlled using a coil-type portable induction heating source. By using a high-frequency parallel resonant converter, the system can be made portable enough to be installed on a compact manipulator. A method using finite element analysis is proposed to generate heating paths over complex shapes that keep temperature uniform in the volume treated.

A heat treatment performed on a 13Cr-4Ni stainless steel component demonstrates the precision of the robotic process.
Development of a Plate Heat Exchanger for High-Temperature and High-Pressure
Authors: Ishihama Kiyoshi , Matsumura Seiichi , Funabiki Takahisa , Kushima Yukiko , Nakamura Junichi , Kusunoki Kenji , Hiwatashi Isamu , Iwaki Mana
Published: February 2014

A gasketed plate heat exchanger that has a seal pressure of 6.5 MPa or more has been developed. This heat exchanger can be applied to heat exchangers (design temperature: 182°C, design pressure: 3.43 MPa) for the residual heat removal (RHR) systems of boiling water reactors (BWR).

Practical use of gasketed plate heat exchangers under the condition of higher temperature and higher pressure has been achieved by developing a high-pressure-retaining plate and frame, as well as a heat- and radiation-resistant gasket. Various element tests related to strength and performance were conducted in the process of this development. A verification test using a prototype heat exchanger was also conducted, and pressure resistance, heat resistance, radiation resistance, endurance against thermal transients, and heat transfer performance have been confirmed.

As a result of this development, gasketed plate heat exchangers can be applied for use under the condition of higher temperature and higher pressure, and various effects such as lower system flow, smaller footprint, easier maintenance, and lower cost for weld inspection are expected, compared to conventional shell & tube heat exchangers.
Smart Asset Management: Using Real Time Transient Data to Determine Equipment Damage, Maintenance Costs, and Operational Strategy in Power Plants
Authors: Kumar Nikhil , Lefton Steven A. , Nissen Aaron , Christensen Garry , Hilleman Douglas , Agan Dwight
Published: February 2014

Real time monitoring for asset management is fast gaining popularity in the power industry. Power plants are transitioning from the initial data gathering to projects creating measurable value for the owner and operator. The authors present an integrated approach, allowing real-time monitoring and advanced analytics for asset management. We specifically look at the changing landscape for plant operators in a renewable integrated grid. Moreover, in today’s volatile electricity markets, most power plants must be flexible; often load following to minimum loads, and frequently cycling on-off. This type of cycling operation can be very damaging to fossil power plants, and add large costs due to increased equipment wear and tear, and adverse heat rate effects. For some large generation units, these costs can amount to millions of dollars per year. These costs can be greatly reduced by proper operations tuning and operator training.

This paper will specifically discuss the value of real time monitoring and advanced analytics to plant operators. We will address the uncertainty, given that plant’s typically follow instructions from dispatch, and provide business case examples of what needs to be done and what value it will actually bring to the industry.
Air Cooled Two-Stage Rankine Cycles for Large Power Plants Operating With Different Working Fluids: Performance, Size and Cost
Authors: Liu Bo , David Franck , Riviere Philippe , Coquelet Christophe , Gicquel Renaud
Published: February 2014

A two stage Rankine cycle for power generation is presented in this paper. It is made of a water steam Rankine cycle and an Organic Rankine bottoming Cycle. By using an organic working fluid with higher density than water, it is possible to reduce the installation size and to use an air-cooled condenser. Following our previous studies, 3 high critical temperature organic fluids, R245fa, R365mfc, isopentane (iC5) and ammonia are tested as potential candidates for this application. The performances of the two stage Rankine cycle operating with those different working fluids are evaluated for a nuclear plant case. The size of system components (heat exchangers and turbine) is estimated for each tested fluid. The influences of their thermodynamic and transport properties are analyzed. In addition, an estimation of the installation cost is done by introducing cost functions.
Vibration Induced Failure Investigation and Evaluation for Main Steam Moisture Separator Drain Tanks
Authors: Adams Timothy M. , Nickholds Shawn , Dubovecky Bruce F. , Watkins Art , Mackowski R. Steven
Published: February 2014

Main Steam Moisture Separator Reheater drain tank nozzles and associated piping at the commercial nuclear power plant have shown a history of tank wall, nozzle and pipe weld failures over an approximate four year cycle. Reports reflect weld failures at the top and bottom nozzles of these drain tanks and in the piping systems associated with the level and instrument trees attached to these tanks. The tanks experience high temperature transient conditions of steam dumped into the tanks. Stresses were induced in the piping and nozzles by vibration during the steam dump and other system transients. Time history field vibration data taken with accelerometers at various points of the pipe system configuration were incorporated and used to develop and benchmark a finite element model to evaluate the stress fields in the piping and the tank. The results of these analyses were then used to recommend modifications to eliminate the cracking issues.
Tensile Stress-Strain Properties and Elastic Modulus of PE 4710 Cell Classification 445574C High Density Polyethylene Pipe Material
Authors: Adams Timothy M. , Wen Jie , Nickholds Shawn , Munson Douglas
Published: February 2014

For corroded piping in low temperature systems replacement of buried carbon steel pipe with high density polyethylene (HDPE) pipe is a cost-effective solution. The ASME Boiler and Pressure Vessel Code, Section III, Division 1, Code Case N755-1 currently permits the use of HDPE in buried Safety Class 3 piping systems. This paper presents the results of tensile testing of PE 4710 cell classification 445574C pipe compliant with the requirements of Code Case N755-1. This information was developed to support and provide a strong technical basis for tensile properties of HDPE pipe. The data may also be useful for applications of HDPE pipe in commercial electric power generation facilities and chemical, process, and waste water plants via its possible use in the B31 series piping codes. The paper provides values for yield stress, yield strain, ultimate strain, and elastic modulus. The standard tensile tests were conducted consistent with the requirements of ASTM D638-10. Specimens were cut in the axial direction from cell composition PE 4710 cell classification 445574C HDPE piping spools. In addition, the results are compared to previous tensile testing conducted on the PE 3608 cell classification 345464C and PE 4710 cell classification 445474C HDPE materials.
Development of Crack Growth Curves and Correlation to Sustained Pressure Test Results for Cell Classification 445574C High Density Polyethylene Pipe Material
Authors: Adams Timothy M. , Hebeisen Jason , Wen Jie , Munson Douglas
Published: February 2014

Code Case N755-1 of the ASME Boiler and Pressure Vessel Code, Section III, Division 1 Code currently permits the use of high density polyethylene (HDPE) in buried Safety Class 3 piping systems. There have been concerns with the Slow Crack Growth (SCG) of HDPE emanating from scratches that may occur during fabrication or installation. The possible use of tensile coupon tests for determining the life span of the pipe with surface scratches could provide a more cost effective testing method than does the use of sustained pressurized crack pipe tests. This paper presents the results of further investigation into the SCG rates of notched PE 4710 HDPE pipe made from a cell classification 445574C bimodal resin. The da/dt versus KI curves were developed from notched coupon testing. Standard fracture methods were then used to predict the failure time of the notched pressurized pipe specimens subjected to long-term hydraulic stress. The results for the SCG depth of the externally notched sustained pressurized pipe tests are provided along with the notched coupon test results. The actual failure times of the notched pressurized pipe tests are compared to the predicted failure times for the same specimens.
Specified Maintenance of Steam Turbines in Geothermal Power Plants
Authors: Gunnarsson Almar , Elisson Ari , Jonsson Magnus , Unnthorsson Runar
Published: February 2014

In a geothermal power plant the working fluid used to produce electricity is often wet steam composed of corrosives chemicals. In this situation, more frequent maintenance of the equipment is required. By constructing an overview for maintenance in geothermal power plants and how it can be done with minimum power outages and cost, the geothermal energy can be made more competitive in comparison to other energy resources.

This work is constructed as a part of a project, which has the aim of mapping the maintenance management system at the Hellisheiði geothermal power plant in Iceland. The object of the project is to establish Reliability Centered Maintenance (RCM) program for Hellisheiði power plant that can be utilized to establish efficient maintenance management procedures. The focus of this paper is to examine the steam turbines, which have been defined as one of the main subsystems of the power plant at Hellisheiði. A close look will be taken at the maintenance needed for the steam turbines by studying for example which parts break down and how frequently they fail.

The local ability of the staff to repair or construct turbine parts on-site is explored. The paper explores how the maintenance and condition monitoring is carried out today and what can be improved in order to reduce cost.

The data collected is analyzed using Failure Mode and Effect Analysis (FMEA) in order to get an overview of the system and to help organizing maintenance and condition monitoring of the power plant in the future. Furthermore, the paper presents an overview of currently employed maintenance methods at Hellisheiði power plant, the domestic ability for maintaining and repairing steam turbines and the power plant’s need for repairs.

The results show that the need for maintenance of the geothermal steam turbines at Hellisheiði power plant is high and that on-site maintenance and repairs can decrease the cost.
Wastewater Treatment in Support of Ash Pond Closures
Authors: Nanni Bernardino P. , Bolender Justin L. , Whittier Spencer D.
Published: February 2014

The Environmental Protection Agency (EPA) is evaluating rules that will not permit the storage of coal combustion residuals (CCRs) in surface impoundments, and require CCRs to be stored in Subtitle C or Subtitle D landfills. In addition, the EPA is evaluating more stringent effluent guidelines for water discharges which may impact NPDES permits in the future. To support these changes, the Tennessee Valley Authority (TVA) is evaluating the elimination of wet CCR handling and surface impoundments at their coal fired facilities. If CCR conveyance is converted to dry methods and the surface impoundments are closed, the other wastewater streams that utilize these impoundments as a point of discharge will also be affected. Therefore, TVA is investigating options to handle the miscellaneous wastewater streams that currently discharge to the impoundments, and meet more stringent effluent limits that may be implemented in the future.

This investigation includes characterization of the existing wastewater streams, determining the effects on wastewater streams associated with future plant modifications and anticipated regulatory changes, developing methods to reduce and reuse wastewater streams to avoid discharge, and developing methods to treat the remaining wastewater streams that may be discharged in accordance with potential future effluent limits.

TVA is in the forefront of addressing the pending EPA rules that may affect CCR handling and storage, and water discharges. This paper discusses and presents the process being used by TVA to address these changes, the results obtained to date, and how this may be applicable to others potentially impacted by these changes.
Characteristics of the Convective Heat Transfer Coefficient at the End Winding of a Hydro Generator
Authors: Klomberg Stephan , Farnleitner Ernst , Kastner Gebhard , Bíró Oszkár
Published: February 2014

Large hydro generators convert the mechanical energy of water turbines into electrical energy. This process is not free of heat losses which have to be dissipated from the machine. For this, different ventilation methods can be applied for an air cooled hydro generator. These methods have not changed very much in the last decades, but there has been a strong enhancement of the calculation and design approaches. State of the art computation methods are thermal and flow networks in combination with 3-dimensional computational fluid dynamics (CFD). The focus of this paper is a CFD analysis of the end winding region as basis for development of correlations between the convective wall heat transfer coefficient (WHTC) and speed and flow rate parameters. These correlations are used as boundary conditions for thermal networks. Furthermore there is also a focus on the influence and sensitivity of the numerical settings on the correlations. This work deals with a reduced numerical model which is designed to calculate a hydro generator fast and accurately by using a steady-state simulation with the mixing plane method. The mixing plane approach is predestined for this kind of design. Considering only one slot section of the end winding bars and stator ducts, the advantages of the stage model can take its full effect. The main advantages are the use of large pitch ratios, periodicities in circumferential direction and the averaging of the fluxes on bands.
Improving Dust Control to Upgrade PRB Coal Handling
Authors: Marshall Daniel
Published: February 2014

Plant management had a mission: to make the Midwestern 646-megawatt power plant a leader in the clean and safe handling of PRB coal.

To accomplish that goal, the organization embarked on an ambitious five-year plan to upgrade the plant’s coal handling system. The plant improved its conveyor transfer points, and installed new dust management systems, controlling dust and spillage, and improving plant safety and efficiency.

This presentation will discuss the initial surveys that led to the development of the 5-year plan, and the resulting project priorities, the problem areas, application points identified, and the various technologies applied. Included in the goals for the upgraded systems installed were the elimination of spillage through the improvement of transfer points on coal-handling conveyors using improved belt support and sealing systems.

In addition, new air cleaners were installed at seven loading zones, and a foam dust-suppression system added at one location to provide dust management throughout the plant’s coal handling system. These new dust control systems allowed the plant to eliminate its older central dust collection system that had greater risks of explosions.

A continued series of monthly inspection and service visits by conveyor maintenance technicians helps continue the coal handling system’s high levels of performance.

This five-year plan helped the power plant take “great leap forward” in controlling dust and spillage from handling PRB coal.
Evaluation of Irradiation Effects on Concrete Structure: Gamma-Ray Irradiation Tests on Cement Paste
Authors: Kontani Osamu , Sawada Shohei , Maruyama Ippei , Takizawa Masayuki , Sato Osamu
Published: February 2014

In assessing reduction of concrete strength under irradiated conditions, reference levels are introduced: 1×1020 n/cm2 for fast neutrons and 2×1010 rad (2×105 kGy) for gamma-rays. Concrete structures are regarded as sound as long as irradiance levels accumulated during long-term operation are less than the reference levels.

Most experimental investigations of irradiation effects on concrete were performed in the 1960’s and 1970’s. However, there is no good explanation of how concrete deteriorates under neutron and gamma-ray irradiation.

Hilsdorf put the primal irradiation test data together to investigate effects of irradiance levels on residual strength ratio of concrete [1]. The reference levels were obtained from his paper. However, the test conditions in which the data quoted by Hilsdorf were obtained are very different from the irradiation and heat conditions usually found in a Light Water Reactor (LWR).

This paper summarizes the interactions between radiation and concrete components and presents the results of gamma-ray irradiation tests on cement paste in order to provide a better understanding of the deterioration mechanisms of concrete under irradiation and heat conditions in LWRs.
Code Automation Technology Based COSINE Software Development
Authors: Ren Hao , Mo Wentao , Liu Shuo , Li Dong , Sun Yang , Zhao Guang
Published: February 2014

Source code automatic generation technology can improve software development’s quality and productivity significantly. However, the existing code generators cannot satisfy nuclear power software development demand. This paper analyzes development feature of scientific computing software and develops a FORTRAN Code Generator (FCG) using C# language. FCG can generate program variables definition FORTRAN source code automatically according to input metadata. FCG also can generate memory allocation source code for dynamic variables in program. Besides, FCG can generate data access interface for global variables in code. Right now, FCG has been applied to source code development of COSINE (Core and System Integrated Engine for design and analysis) software package. Development practice has proved that FCG can improve development efficiency of nuclear power software greatly.
Concept and Application of Distributed Compressed Air Energy Storage Systems Integrated in Utility Networks
Authors: Petrov Miroslav P. , Arghandeh Reza , Broadwater Robert
Published: February 2014

Distributed energy storage has been recognized as a valuable and often indispensable complement to small-scale power generation based on renewable energy sources. Small-scale energy storage positioned at the demand side would open the possibility for enhanced predictability of power output and easier integration of small-scale intermittent generators into functioning electricity markets, as well as offering inherent peak shaving abilities for mitigating contingencies and blackouts, for reducing transmission losses in local networks, profit optimization and generally allowing tighter utility control on renewable energy generation. Distributed energy storage at affordable costs and of low environmental footprint is a necessary prerequisite for the wider deployment of renewable energy and its deeper penetration into local networks.

Thermodynamic energy storage in the form of compressed air is an alternative to electrochemical energy storage in batteries and has been evaluated in various studies and tested commercially on a large scale.

Distributed compressed air energy storage (DCAES) systems in combination with renewable energy generators installed at residential homes, public or commercial buildings are a viable alternative to large-scale energy storage, moreover promising lower specific investment than batteries if a mass-market is established. Flexible control methods can be applied to DCAES units, resulting in a complex system running either independently for home power supply, or as a unified and centrally controlled utility-scale energy storage entity.

This study aims at conceptualizing the plausible distributed compressed-air energy storage units, examining the feasibility for their practical implementation and analyzing their behavior, as well as devising the possible control strategies for optimal utilization of grid-integrated renewable energy sources at small scales. Results show that overall energy storage efficiency of around 70% can be achieved with comparatively simple solutions, offering less technical challenges and lower specific costs than comparable electrical battery systems. Furthermore, smart load management for improving the dispatchability can bring additional benefits by profit optimization and decrease the payback time substantially.
Thermoeconomic Evaluation of Integration Concepts for Solar and Biomass Hybrid Power Plants
Authors: Salomon Popa Marianne , Petrov Miroslav P. , Krothapalli Anjaneyulu
Published: February 2014

Solar thermal energy and biomass fuels are often available at locations where they can benefit from combined hybrid energy utilization methods for the generation of electricity, representing suitable and advantageous integration alternatives. The feasibility of concentrating solar power (CSP) systems depends on cost limitations, desired installed power capacity and direct solar insolation, where smaller scales and low-cost solutions can often be preferred to large-scale investment-intensive installations. Biomass residues of various types, on the other hand, can be considered as proven fuels for small-to-midscale utility or industry based power or cogen arrangements and utilized through various technologies. The thermodynamic integration between a biomass fired power plant and a CSP unit can help to significantly increase the availability of the plant, improve its partial load characteristics, compensate for the intermittency of the solar energy resource while preserving the purely renewable profile of the generated electricity, and at the same time showing better overall performance when compared to two separate plants while avoiding the need for costly energy storage solutions.

Biomass fuels can help reach better steam conditions in a steam plant based on CSP-generated steam, and thus improve the efficiency of energy conversion for the integrated hybrid system if compared with two individual single-fuel power units. In this study, an overview of feasible solar-biomass integration concepts is presented. A deeper thermoeconomic analysis of a selected integrated utility-scale biomass and CSP electricity generation plant is attempted, with certain simplifications. Furthermore, a multiobjective optimization strategy is regarded as very necessary and thus included in the analysis, where several major environmental aspects plus the cost of electricity are involved and defined in terms of desired parameters and conditions representative to Central Europe and Southeastern United States. The results are compared with conventional power generation alternatives. On that basis, a low-parameter CSP solution integrated with conventional biomass-fired combustion unit, where solar-generated steam is being superheated by the biomass fuel, has been chosen as the focus of the analysis in this study.
Nuclear Air-Brayton Combined Cycle (NACC) With Natural Gas Peak Power
Authors: Forsberg Charles , Curtis Daniel
Published: February 2014

The Fluoride-Salt-Cooled High-Temperature Reactor (FHR) is a new reactor concept that uses the graphite-matrix coated-particle fuel from gas-cooled reactors and a high-temperature liquid salt coolant. The reactor exit temperatures exceed 700°C with reactor inlet temperatures of ∼600°C. Because of these high temperatures the FHR can be coupled to a nuclear air-Brayton combined-cycle (NACC) plant with one or more air-Brayton turbines with hot exhaust directed to a steam recovery boiler.

Under normal base-load operating conditions, air is compressed, heated using salt-air heat exchangers, passed through a turbine, and exhausted to a heat recovery boiler, and added electricity is made from the steam that is generated. The NACC can have one or more salt-to-air reheat stages. After air compression and nuclear heating, the hot compressed air is above the auto-ignition temperature of natural gas (NG). Natural gas can be injected to increase gas temperatures and produce peak power. Because the plant operates continuously as a base-load system connected to the grid and there is no need to control the fuel-to-air ratio, the peak power can be varied and increased rapidly. At times of low electricity prices, steam from the heat recovery boiler can be sold to industrial users at lower prices than they can generate it from NG but above its value for electricity generation. The incremental capital cost for peaking capabilities is less than the cost of stand-alone NG plants. There is the potential for the NG-to-electricity efficiencies exceeding those of stand-alone NG plants. These capabilities imply plant revenue 20 to 50% greater than from an equivalent base-load nuclear plant.

The market requirements are being assessed to determine the requirements for the FHR and NACC power cycle. As a new-type of plant, much additional work is required to understand the design options and limitations.
Condition Assessment of Air Cooled Electric Generators With EMI Diagnostics
Authors: Timperley James E.
Published: February 2014

Since 1980 EMI (electromagnetic interference) Diagnostics has provided information on the electrical and mechanical condition of several hundred electric generators. This on-line technique has been applied to many sizes and designs of 2-pole and 4-pole steam and combustion turbines, air cooled and hydrogen cooled generators. This paper provides several case studies of electrical and mechanical deterioration identified with EMI Diagnostics for air cooled machines. Several methods that enhance analysis of EMI Diagnostics are presented, such as trending, data comparison at different loads as well as data comparison on-line and off-line but energized.
Integrated Solar Combined Cycle Plants Using Solar Towers With Thermal Storage to Increase Plant Performance
Authors: Peterseim Juergen H. , Tadros Amir , Hellwig Udo , White Stuart
Published: February 2014

In Australia both natural gas and an excellent solar irradiance are abundant energy sources and its combination is one option to implement concentrating solar power (CSP) systems in Australia’s traditionally low cost electricity market. The recently introduced carbon pricing mechanism in Australia is likely to steer investment towards combined cycle gas turbine (CCGT) plants. This will also lead to further plants being built in high solar irradiance areas where CSP could provide valuable peak capacity. Hybridisation would enable more competitive power generation than standalone CSP systems as hybrid plants share equipment, such as steam turbine and condenser, therewith lowering the specific investment.

This paper investigates the novel hybridization of CCGT and solar tower systems to increase the efficiency of integrated solar combined cycle (ISCC). Currently, all ISCC plants use parabolic trough systems with thermal oil as this technology is most mature. However, increases in plant efficiency, simpler solar tower integration as well as further synergies of solar tower ISCC systems, such as joint use of tower as CCGT stack, are likely to enhance the economic viability of new ISCC plants. In addition to a technical concept description this paper outlines the ideal sites for ISCC plants in Australia and presents a 200MWe ISCC case study with 3h molten salt thermal storage for the conversion of the Port Hedland open cycle gas turbine (OCGT) facility in Western Australia into a solar tower ISCC plant.
A Dry Low-NOx Gas-Turbine Combustor With Multiple-Injection Burners for Hydrogen-Rich Syngas Fuel: Testing and Evaluation of its Performance in an IGCC Pilot Plant
Authors: Asai Tomohiro , Dodo Satoschi , Akiyama Yasuhiro , Hayashi Akinori , Karishuku Mitsuhiro , Yoshida Shohei
Published: February 2014

Success of oxygen-blown integrated coal gasification combined cycle (IGCC) technology requires gas turbines capable of achieving dry low nitrogen oxides (NOx) combustion of hydrogen-rich syngas for low emissions and high plant efficiency. The authors have been developing a “multiple-injection burner” to achieve dry low-NOx combustion of such hydrogen-rich fuels using surrogate fuel composed of hydrogen, nitrogen, and methane. The purpose of this paper is to report test results of a multi-can combustor equipped with multiple-injection burners for a practical syngas fuel in an IGCC pilot plant and to evaluate its performance. The syngas fuel consisted of hydrogen, nitrogen, and carbon monoxide up to approximately half of its volume. In the test, the combustor achieved stable and reliable operation from ignition through partial load to the maximum load, and achieved NOx emissions of 15.1 ppm (at 15% oxygen) at the maximum load. These findings demonstrated that the combustor achieves dry low-NOx combustion of the syngas fuel in the IGCC pilot plant.
One Dimensional Model for Rotating Channels in the Turbine System: Part 1 — Formulation and Validation for Single Phase Flow
Authors: Prabhudharwadkar Deoras , Dweik Zain , Krishnan R. Murali
Published: February 2014

The secondary air flow system of a gas turbine performs the cooling and sealing applications in those parts of the turbine which would otherwise be exposed to the high temperatures resulting in their life reduction or even failures. Accurate analysis of the secondary system is therefore necessary to ensure the safe design of the engine and accurate life predictions. The secondary system is analyzed through the flow network analysis which comprises of chambers or cavities connected through flow passages or restrictions (e.g. seals). The narrow flow channels form a majority of these passages especially in the turbine blades cooling system.

This paper provides a detailed formulation of a one-dimensional model for steady, compressible flow inside a channel which is based on the solution of two equations for a coupled system of mass, momentum and energy equations. The model is applicable over a wide range of subsonic to supersonic flow conditions. It has been validated for the choked flow situation and also has the capability to capture normal shocks. Hence, this model provides a fast, accurate and robust channel simulation technique that is compatible with a complex network analysis.
Study on the Reliability Improvement of a Mechanical Seal for the Primary Loop Recirculation Pumps (PLR Pump)
Authors: Hikida Naoto , Torigoe Hiroyuki , Nishiyama Kikuo , Sugiyama Kenichi
Published: February 2014

Primary Loop Recirculation pump (PLR pump) for Boiling Water Reactor (BWR) uses a mechanical seal as a shaft seal device, which the seal material is made of a ceramic. Recently, a new ceramic suitable as a seal material has been developed. We will explain about the introduction of the material to a mechanical seal for the PLR pump. First, we checked the material characteristics of the ceramic. Next, we carried out the abrasion acceleration test at the mechanical seal test facility for PLR pump, and performed an analysis of seal face deformation for the applied ceramic. Then, we performed a full scale test that simulated the operation pattern of the PLR pump. As a result, we confirmed that the new ceramic property suits for the use as a mechanical seal for the PLR pump.
A Natural Circulation Waste Heat Recovery System for High Temperature Gas-Cooled Reactor Used and/or Spent Fuel Tanks: Part II — Theoretical and Experimental Validation
Authors: Senda Franck M. , Dobson Robert T.
Published: February 2014

Since the beginning of the twenty-first century, energy conservation has become a major feature of interest in most industrialised countries. The economics of saving energy versus wasting it has driven industrial activists to pay more attention to energy conservation. The implementation of energy conservation requires that all the possibilities of counteracting any potential loss of energy must be considered. This includes reducing heat losses from furnaces, thermal insulation, repair of steam leaks in power plants, heat loss from nuclear reactors, and all other practices that may be implemented rapidly and, preferably at low cost. Once this is achieved, further strategies have to be developed to stabilise short-term energy conservation in systems by implementing permanent solutions. Permanent energy conservation solutions are more expensive, but result in energy benefits over many years. These permanent solutions are referred to as Waste heat recovery systems (WHRSs). This paper presents potential application of WHRSs in high-temperature reactors technology. WHRSs have attracted the attention of many researchers over the past two decades, as using waste heat improves the system overall efficiency, notwithstanding the cost of extra plant. WHRSs require specially designed heat recovery equipment, and as such the used and/or spent HTR fuel tanks were considered by the way of example. An appropriately scaled system was designed, constructed and tested to demonstrate the functioning of such a cooling system first and validated the theoretical model that simulates the heat transfer process in the as-designed WHRS. It is a one-dimensional flow model assuming quasi-static and incompressible liquid and vapour flow its mathematical simulations as developed in Part I (Senda and Dobson, 2013). Two separate and independent cooling lines, using natural circulation flow in a particular form of heat pipes called thermosyphon loops were used to ensure that the fuel tank (FT) is cooled when the power conversion unit has to be switched off for maintenance, or if it fails.