bluuebunny/crossref_metadata_2025_split huggingface dataset:
Technology Choice and Water Consumption for Coal Electricity Production With Carbon Capture and Storage
Authors: Harto Christopher , White Ellen , Horner Robert , Schroeder Jenna 
Published: November 2014

Water consumption is an important consideration when evaluating technologies for carbon capture and storage (CCS). It may in fact become a critical factor in certain regions where water is increasingly a source of conflict. For this reason, water consumption has the potential to become a challenging obstacle to adoption of CCS technologies. This analysis seeks to improve understanding of relative water costs of different CCS technology options. It also helps to identify areas where water use may in fact become a challenge and reveal opportunities for technological improvements that can help minimize these challenges.
A life cycle assessment approach was utilized to analyze both the water consumption from carbon capture and storage projects. While there have been previous analyses that have looked at the direct water consumption for some capture processes, there have been few studies that have taken a detailed look at water consumption throughout the complete life cycle of the of electricity production with CCS. This effort expands the system boundaries beyond those of previous analysis while evaluating a range of system configurations to facilitate technology comparison.
The range of system configurations considered in this analysis included both pre and post combustion capture systems and multiple sequestration scenarios. The system boundaries for the analysis include fuel production, fuel transport, combustion, capture, CO2 transport, and storage. Water consumption for conventional fossil fuel systems are also calculated for comparison purposes.
The results show that while all carbon capture technology pathways result in a net increase in water consumption relative to conventional coal generation, the choice of technology, especially capture technology, can play a significant role in minimizing the increase in water consumption. Integrated gasification combined cycle coal plants with carbon capture were found to be significantly more water efficient than either conventional power plants with post combustion capture or plants utilizing oxy-combustion processes. Also, while other stages of the life cycle do consume water, the volumes were small relative to the power plant operations and capture stages.
Sootblowing Optimization Improves Heat Rate and Enhances Operational Flexibility at Hawthorn Unit 5
Authors: Parikh Neel J. , Rogge Peter , Luebbert Kenneth 
Published: November 2014

Coal-fired units are increasingly expected to operate at varying loads while simultaneously dealing with various operational influences as well as fuel variations. Maintaining unit load availability while managing adverse effects of various operational issues such as, flue gas temperature excursions at the SCR inlet, high steam temperatures and the like presents significant challenges. Dynamic adjustment of sootblowing activities and different operational parameters is required to effectively control slagging, fouling and achieve reliability in unit operation.
Closed-loop optimizers aim to reduce ongoing manual adjustments by control operators and provide consistency in unit operation. Such optimizers are typically computer software-based and work by interfacing an algorithmic and/or artificial intelligence based decision making system to plant control system [1]. KCP&L is in the process of implementing Siemens SPPA-P3000 combustion and sootblowing optimizers at several Units.
The Sootblowing Optimizer solution determines the need for sootblowing based on dynamic plant operating conditions, equipment availability and plant operational drivers. The system then generates sootblower activation signals for propagation in a closed-loop manner to the existing sootblower control system at ‘optimal’ times.
SPPA-P3000 Sootblowing Optimizer has been successfully installed at Hawthorn Unit 5, a 594-MW, wall-fired boiler, firing 100 percent Powder River Basin coal. This paper discusses implementation approach as well as operational experience with the Sootblowing Optimizer and presents longer-term operational trends showing unit load sustainability and heat rate improvement.
Global-Local Analysis of a Composite Riser
Authors: Akula Venkata M. K. 
Published: November 2014

Composite materials are often utilized in weight-critical applications, owing to their higher specific strength\stiffness characteristics. In addition, composite materials also possess qualities such as better corrosion resistance, lower coefficient of thermal expansion, etc., which makes them a potential material choice for riser systems in high pressure and high temperature environments. However, design certification of risers using the finite element method requires modeling and analysis techniques, centric to the multi-layered nature of composite structures.
Riser systems, owing to their high aspect ratios, have traditionally been modeled with beam elements. The methodology for extracting the stress results and certifying a metallic riser is well established in the Oil and Gas industry. However, for analyzing a composite riser, three-dimensional shell or hexahedral elements are generally required to capture the through-the-thickness (or pipe cross-sectional) variation of structural response, especially in critical regions such as touchdown point, pipe-intersection zones, etc.
In this paper, a method for analyzing a detailed local model (discretized with shell\hexahedral elements) driven by results from a global model (meshed with beam elements) is presented. The global model captures the structural response whereas the local model provides cross-sectional stress\strain information for individual layers. Although the method is illustrated for a composite riser, it is also applicable to metallic structures.
Evaluation of ASME Pressure Vessel Code Prohibitions on Rod and Bar Stock and Potential Remedies
Authors: Aumuller John J. , Carucci Vincent A. 
Published: November 2014

The ASME Codes and referenced standards provide industry and the public the necessary rules and guidance for the design, fabrication, inspection and pressure testing of pressure equipment. Codes and standards evolve as the underlying technologies, analytical capabilities, materials and joining methods or experiences of designers improve; sometimes competitive pressures may be a consideration. As an illustration, the design margin for unfired pressure vessels has decreased from 5:1 in the earliest ASME Code edition of the early 20th century to the present day margin of 3.5:1 in Section VIII Division 1. Design by analysis methods allow designers to use a 2.4:1 margin for Section VIII Division 2 pressure vessels.
Code prohibitions are meant to prevent unsafe use of materials, design methods or fabrication details. Codes also allow the use of designs that have proven themselves in service in so much as they are consistent with mandatory requirements and prohibitions of the Codes. The Codes advise users that not all aspects of construction activities are addressed and these should not be considered prohibited. Where prohibitions are specified, it may not be readily apparent why these prohibitions are specified. The use of “forged bar stock” is an example where use in pressure vessels and for certain components is prohibited by Codes and standards.
This paper examines the possible motive for applying this prohibition and whether there is continued technical merit in this prohibition, as presently defined. A potential reason for relaxing this prohibition is that current manufacturing quality and inspection methods may render a general prohibition overly conservative. A recommendation is made to better define the prohibition using a more measurable approach so that higher quality forged billets may be used for a wider range and size of pressure components.
Jurisdictions with a regulatory authority may find that the authority is rigorous and literal in applying Code provisions and prohibitions can be particularly difficult to accept when the underlying engineering principles are opaque. This puts designers and users in these jurisdictions at a technical and economic disadvantage.
This paper reviews the possible engineering considerations motivating these Code and standard prohibitions and proposes modifications to allow wider Code use of “high quality” forged billet material to reflect some user experiences.
Development of Enertech’s Advanced Normally Open NozzleCheck Valves for Generation III+ Nuclear Power Plants
Authors: Mkrtchyan Haykaz 
Published: November 2014

Enertech introduced the first Normally Open NozzleCheck valves to the nuclear power industry nearly 20 years ago. This passive valve design was developed to address reoccurring maintenance and reliability issues often experienced by various check valve types due to low or turbulent flow conditions. Specifically, premature wear on the hinge pins, bushings and severe seat impact damage had been discovered in several applications while the systems were in steady state operating conditions.
Over the last two decades, Enertech has continued to improve upon the design of the valve, with the culmination coming most recently in support of Generation III+ passive reactor requirements. This entirely new valve is designed with minimal stroke, ensuring quick closure under low reverse flow conditions which no other check valve design could support. Additionally, features such as first in kind test ports, visual inspection points, and the ability to manually stroke the valve in line have resolved many of the short comings of previous inline welded flow check valves.
Most importantly, advanced test based methodologies and models developed by Enertech, allow for accurate prediction of NozzleCheck valve performance. This paper presents the development of Enertech’s advanced Normally Open NozzleCheck Valve for Generation III and III+ nuclear reactor designs. The Valve performance was initially determined by using verified and validated computational fluid dynamic (CFD) methods. The results obtained from the CFD model were then compared to the data gathered from a prototype valve that was built and tested to confirm the performance predictions. Enertech has fully tested and qualified the Normally Open NozzleCheck valve which is specifically designed for applications that require a high capacity in the forward flow direction and a quick closure during low reverse flow condition with short stroke to minimize the hydraulic impact on the system.
Effects of Mechanical Loading on Residual Stress and Fracture: Part II — Validation of the BS 7910:2013 Rules
Authors: Hadley Isabel , Smith Simon 
Published: November 2014

Failure of welded structures due to the presence of flaws is typically driven by a mixture of applied and residual stresses, yet in most cases only the former are known accurately. In as-welded structures, a typical assumption is that the magnitude of welding residual stress is bounded by the room temperature yield strength of the parent material. The UK flaw assessment procedure BS 7910:2013 also assumes that mechanical loading (either as a result of proof testing or during the initial loading of an as-welded structure) will bring about a relaxation in residual stress. Conversely, the UK structural assessment code for nuclear structures, R6, contains a warning on the ‘limited validation’ of the BS 7910 approaches for stress relaxation and suggests that they should be used ‘with caution’. The aim of this study was therefore to review the basis of the BS 7910 clauses on stress relaxation with a view to harmonising the BS 7910 and R6 rules for cases in which the original welding residual stress distribution is not known.
A companion paper describes the history of the residual stress relaxation clauses of BS 7910. A considerable programme of work was carried out in the late 1980s to justify and validate the clauses, using a range of experimental and numerical work. This included analysis of work carried out by the UK power industry and used in the validation of the R6 procedure. The full underlying details of the work have not hitherto been available in the public domain, although the principles were published in 1988. The approach proposed in BS 7910 combines ‘global’ relaxation of residual stress (Qm) under high mechanical load with ‘local’ enhancement of crack tip driving force through the adoption of a simplified primary/secondary stress interaction factor, ρ. This is different from the method adopted by R6, but appears to be equivalent to allowing negative values of ρ under conditions of high primary stress.
A re-analysis of the original TWI work, using the current version of BS 7910, has shown nothing to contradict the approach, which represents a workable engineering solution to the problem of how to analyse residual stress effects in as-welded structures rapidly and reasonably realistically when the as-welded stress distribution is unknown.
Fracture Toughness Behavior of Complex Cracks in Dissimilar Metal Welds
Authors: Rudland D. , Benson M. , Shim D.-J. 
Published: November 2014

Currently, J-estimation scheme procedures to predict the load-carrying capacity of idealized circumferential through-wall cracks in nuclear grade piping materials employ analytical or numerical procedures coupled with the fracture toughness of the material to predict the pipe response. However, with the advent of primary water stress corrosion cracking (PWSCC), complex-shaped cracks occur in dissimilar metal (DM) welds. These welds consist of a nickel-based weld joining stainless steel and carbon steel base metals.
The NRC Office of Nuclear Regulatory Research (RES) is conducting a program to investigate the behavior of circumferential through-wall and complex cracks in DM welds. In a prior paper, a series of full-scale pipe bend and laboratory-sized fracture experiments were documented. Initial analyses of those test results suggest that reasonable prediction of through-wall crack response is obtained from typical J-estimation scheme procedures using the weld toughness from a compact tension (CT) specimen and the appropriate material strength. In addition, the J-R curves from the through-wall cracked pipe tests, calculated using published η-factor solutions and numerical techniques, were very similar to the CT J-R curves. In this paper, the fracture toughness for the circumferential complex cracked experiments, which was developed from a modified η-factor solution, is presented. These results are compared to the CT and through-wall crack pipe J-R curve results. In addition, predictions of load carrying capacity using the complex crack J-R curve and through-wall crack J-estimation schemes are presented and illustrate the need for the development of a complex crack J-estimation scheme. To support this development, a net-section collapse solution and a modified K-solution is presented. Finally, the need for additional work to generalize the elastic solution and its incorporation into a closed-form J-estimation scheme is discussed.
Finite Element Analysis of a Pipe Junction With a Thermal Sleeve Subject to Thermal and Pressure Transient Events
Authors: Pattinson Alec , Dodds James , Hugill Peter , Reed Gary 
Published: November 2014

This paper describes the results of a Finite Element Analysis (FEA) of a pipe junction consisting of a thermal sleeve subject to rapid temperature changes. The purpose of the analysis was to utilise derived Computational Fluid Dynamic (CFD) temperatures to calculate stresses on the pressure boundary and thermal sleeve of a pipe junction.
Several transient events were modelled and analysed. Work was then carried out in accordance with the relevant articles of the ASME Boiler and Pressure Vessel Code, Section III, sub-section NB. Work included, design, hydrotest, Level A (including fatigue) and simplified elastic plastic assessments, however not presented within this paper.
The likely fracture performance of the pressure boundary was also investigated, however are also not presented within this paper.
Account for Metal to Metal Contact Between Gasket Centering Ring and Flange Facing in Calculation Using the XP CEN\TS 1591-3 Method: Comparison With Other Analytical Method and Finite Element Analysis
Authors: Lejeune Hubert , Ton That Yann 
Published: November 2014

The european standard EN1591-1 [1], initially published in 2001, defines a calculation method for bolted gasketed circular flanges, alternative to the TAYLOR-FORGE method, used as the basic method in most codes. In 2007, a new part, XP CEN/TS 1591-3 [2], has been added to the EN1591 series. This technical specification enables to take into account the Metal to Metal Contact (MMC), appearing inside the bolt circle on some assemblies. Due to a lack of industrial feedback and detailed validation, this document has not been raised to the standard status.
In that context, under the request of its Pressure Vessel and Piping commission, CETIM has performed a study comparing this calculation method to Finite Element Analysis (FEA) on several industrial configurations. After a description of the XP CEN/TS 1591-3 calculation method, the major results obtained for spiral wound gasketed joints where MMC appears between centering ring and flange facing are presented and compared with FEA results. Moreover, results obtained with other classical analytical calculation methods as TAYLOR FORGE and EN1591-1 on the same Bolted Flange Connections (BFC) configuration are also analysed and compared to XP CEN/TS 1591-3 results.
Automated Fracture Mechanics and Fatigue Analyses Based on Three-Dimensional Finite Element for Welding Components
Authors: Nakamura Hitoshi , Tajima Seiichi , Hazama Osamu , Gu Wenwei 
Published: November 2014

This paper describes the structure and application of a software system that automates the fatigue initiation and crack propagation analysis based on FEM. The system automatically performs necessary procedures to track propagation history of cracks: insertion of a crack and updating of three-dimensional finite element mesh in accordance with the crack propagation. Most of the meshing is carried out by a Delaunay tessellation method. A tubular hexahedral mesh is generated at the crack front and the fracture mechanics parameters are computed using commercial codes to ensure accuracy. The generation of this tubular hexahedral mesh is fully automatic as well.
The system is equipped with a function to automatically perform fatigue analyses using the stress-strain histories at nodes of a three-dimensional FEM model. The standard low cycle fatigue analysis approach is adopted. Using the function, cumulative fatigue for a given FEM model is provided. Some analyses for several examples were carried out for validation. The important example is the surface crack propagation in steel pipes with residual stress.
The Role of Composite Repair Technology in Rehabilitating Piping and Pipelines
Authors: Alexander Chris 
Published: November 2014

Composite materials have been used to repair high pressure pipelines and piping for the better part of 20 years. The initial aim of composite repair technology was focused on reinforcing corrosion. However, composite materials are now used to reinforce a wide array of anomalies and features including dents, mechanical damage, vintage girth and seam welds, wrinkle bends, elbows, tees, branch connections, and even cracks.
In this paper the author provides an industry overview including results and insights from multiple research programs sponsored by composite repair manufacturers, pipeline operators, and the Pipeline Research Council International, Inc. Discussions will also be included regarding the important role that the ASME PCC-2 and ISO 24817 composite repair standards have in ensuring that quality control measures are in place. The ongoing focus of these efforts has been to demonstrate to industry the capabilities that composite repair systems have to provide long-term solutions for reinforcing damaged equipment.
Burst Tests of B16.9 Welded Tees
Authors: Stonehouse Mark , Paulin Tony , Becht Charles , Becht Charles 
Published: November 2014

This paper presents the results of a small sample of ASME B16.9 welding tee burst tests. The intent of this study was to make a comparison between what is commonly accepted in industry as a B16.9 welding tee to the burst test requirements of B16.9 paragraph 9. The tests conducted show that the current fabrication techniques and some accepted criteria for B16.9 certification can produce thin sections in the tee which do not meet the required burst test pressures.
The test descriptions and results are presented as well as recommendations for future study and potential modifications to the ASME B16.9 standard to address the concerns.
Application of 3D X-Ray Tomography to Enhance the Calibration of Ductile Fracture Models
Authors: Daly Michael , Leonard Fabien , Sherry Andrew H. 
Published: November 2014

Reactor Pressure Vessels (RPV) are manufactured from medium strength low allow ferritic steel specifically selected for its high toughness and weldability. The normal operating temperature of RPV steels is sufficiently high to ensure that the material remains ductile throughout its service life with an extremely low probability of cleavage under normal and off-normal loading conditions. Understanding and having the ability to predict ductile fracture behaviour is consequently important.
The ductile fracture mechanism is characterised by the nucleation, growth and coalescence of voids at initiating particles within the volume of high triaxial stress and plastic strain ahead of a crack-tip or stress concentrator. The fracture properties of the steels are conventionally determined using standard pre-cracked compact test specimens. Mechanistically based models of fracture can be calibrated against those data.
This paper describes the use of 3D laboratory X-ray tomography to characterise the void distribution associated with the ductile fracture in test specimens and use the data to calibrate the Gurson-Tvergaard-Needleman ductile fracture model.
The tomography successfully captures voids ≥ 6um in diameter and has been used to define the average distribution of void volume fraction as a function of distance below the fracture surface. The tomography results also allow an estimate of the critical and final void volume fractions to be made as well as capture secondary void peaks well below the fracture surface.
This distribution of voids was used to calibrate the Gurson-Tvergaard-Needleman model in order to correlate experimental observations with the finite element models. The models have been able to replicate the observed trends of the void volume fraction distributions away from the fracture surface including the secondary peaks observed by tomography and to reproduce similar J-R curve behaviour as that observed in the test specimens.