bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling of Transient Flow in Pipeline Systems Using Incremental Differential Quadrature Method
Authors: Hashemi M. R. , Abedini M. J.
Published: July 2009

Our objective in this paper is to introduce the detailed implementation and performance of a new method so called Incremental Differential Quadrature Method (IDQM) for modeling transient flow in pipelines. The basics of IDQM, its structure, and the formulation of the method for numerical simulation of transient flow in pipelines are discussed. The results obtained from this numerical exercise are compared with the method of characteristics and experimental data. The test case studies show that the best structure for IDQM solution is cosine grid distribution. In terms of viscous damping, the inclusion of unsteady friction term in the governing equations can improve the results significantly. This study demonstrates that IDQM can be regarded as a new alternative for numerical solution of transient flow such as water hammer in pipelines. IDQM is highly implicit in nature which makes the method unconditionally stable. It gives accurate results using few grid points.
Extended Distance Fiber Optic Monitoring for Pipeline Leak and Ground Movement Detection
Authors: Ravet Fabien , Briffod Fabien , Nikle`s Marc
Published: July 2009

We present a comprehensive solution for in-line and realtime monitoring of long distance pipeline using distributed fiber optic sensors. The technique is based on Brillouin scattering and is capable of measuring strain and temperature over distances larger than 150 km with meter resolution using a single instrument. The solution includes ground movement, leakage and third party intrusion detection. The solution presentation is supported by experimental results and practical cases of implementation.
Parametric Study on the Effect of Geometric Imperfections on the Bending Capacity of High-Strength Linepipes
Authors: Sato Takashi , Mikami Yoshiki , Mochizuki Masahito , Suzuki Nobuhisa , Toyoda Masao
Published: July 2009

It is important to determine the bending capacity of linepipes for strain-based design. Several empirical formulas have been proposed in order to evaluate the bending capacity of linepipes, which are presented in terms of the D/t ratio, the internal pressure, the yield ratio and the material strength. FEAs considering these parameters have been performed, however, it has been reported that the results do not always agree with experimental results. It has already been clarified that the geometric imperfections must be considered so that two types of results agree. This paper presents the results of a parametric study examining the effect of geometric imperfections on the bending capacity of linepipes. In addition, the effect of combining two or all of three types of geometric imperfections on the bending capacity was also investigated. When a single imperfection was taken into consideration in the FE models, it was quantitatively clarified that the bending capacity of linepipes improves with a decreasing geometric imperfection. Moreover, when combined geometric imperfections were taken into consideration in the FE models, it was also clarified that the largest imperfection tends to dominate the results and the smallest imperfection does not necessarily affect the bending capacity of the linepipes.
Markov Description of Corrosion Defects Growth and Its Application to Reliability Based Inspection and Maintenance of Pipelines
Authors: Timashev S. A. , Malyukova M. G. , Poluian L. V. , Bushinskaya A. V.
Published: July 2009

The paper describes a Markov model of corrosion growth of pipe wall defects and its implementation for assessing the conditional probability of pipeline failure and optimizing pipeline repair and maintenance. This pure growth Markov model is of the continuous time, discrete states type. This model is used in conjunction with the geometrical limit state function (LSF) to assess the conditional probability of failure of pressurized pipelines when the main concern is loss of containment. It is shown how to build an empirical Markov model for the length, depth and width of defects, using field data gathered by In-line inspection (ILI) or direct assessment (DA) or by using a combination of a differential equation (DE) that describes defect parameter growth with the Monte Carlo simulation method. As a result of implementation of this approach the probability for the defect parameters being in a given state (analog of a histogram) and the transition intensities (from state to state) are easily derived for any given moment of time. This approach automatically gives an assessment of the probability of failure of a pipeline segment, as it is derived using the data from a specific pipeline length. This model also allows accounting for the pipeline failure pressure LSF. On the basis of this model an algorithm is constructed for optimizing the time of the next inspection/repair. This methodology is implemented to a specific operating pipeline which was several times inspected by a MFL inspection tool. The expected number and volume of repairs depend on the value of the ultimate permissible pipeline failure probability. Sensitivity of pipeline conditional failure rate and optimal repair time to actual growth rate is investigated. A brief description of the software that implements the described above technology is given.
A Comprehensive Distributed Pipeline Condition Monitoring System and Its Field Trial
Authors: Strong Andrew P. , Sanderson Norman , Lees Gareth , Hartog Arthur , Twohig Richard , Kader Kamal , Hilton Graeme , Khlybov Artem
Published: July 2009

In this paper we describe a unique and innovative pipeline and flowline monitoring system which has been developed by Schlumberger in collaboration with BP. Applications of the system include pipeline/flowline integrity monitoring and overall optimization of the operation of the pipeline/flowline. Details of the pipeline condition monitoring system (PCMS) components are provided along with the results from comprehensive field trials. The system uses novel optical fibre distributed sensors to provide simultaneous distributed measurements of temperature, strain and vibration for the detection, monitoring, and location of events including: • Third Party Interference (TPI), including multiple simultaneous disturbances; • Geo-hazards and landslides; • Gas and oil leaks; • Permafrost protection. The system performs analysis of the combination of measurands to provide the operator with an event recognition and location capability allowing the most appropriate early response to be initiated. Through the use of newly developed remote, optically powered amplification, an unprecedented detection range of 100km is achieved without the need for any electronics and therefore remote power in the field. A system can thus monitor 200km when configured to monitor 100km in two directions from a single location. As well as detecting the external conditions leading to leaks, this fully integrated system provides a means of detecting and locating small leaks in gas pipelines below the threshold of present online leak detection systems based on monitoring flow parameters. Other benefits include the enhancement of the operator’s existing integrity management program and the potential for reductions in surveillance costs and HSE risks. In addition to onshore pipeline systems this combination of functionality and range is available for practicable monitoring in a wide range of other applications such as: • Long subsea flowlines; • Umbilicals; • Power cables; • Offshore riser systems; • Settlement in tank farms; • Facilities perimeter security. An important deliverable from this work includes the design and field testing of a bespoke optical sensor cable, designed to be sensitive to ground movement to allow distributed strain measurement whilst withstanding the rigors of the pipeline environment. In this paper, we describe the new optical sensing methods developed, and the results of the extensive field trials performed during 2007 and 2008 to fully evaluate and prove the system for use on long hydrocarbon transmission pipelines. Specifically, we demonstrate the detection of small gas releases, simulated earth movement and a number of different types of third party interventions at the full 100km target range.
Effect of Cool Deformation on the Mechanical Properties of Low C Microalloyed Steels
Authors: Calvo Jessica , Elwazri Abdelbaset , Bai Dengqi , Yue Stephen
Published: July 2009

The application of small amounts of deformation at coiling temperatures, i.e. cool deformation, has been shown to be an effective method to improve the mechanical properties of low carbon microalloyed steels. Improvements are related to the effect of cool deformation on strengthening mechanisms such as precipitation, grain refinement and phase transformation. However, it is not clear to what extent mechanical properties will improve when cool deformation is applied after TMP (Thermomechanical Processing). In this work, cool deformation was applied in torsion after a simulation of an industrial rolling schedule to samples of six experimental low carbon steels containing different amounts of Nb, Cu, Mo and Si. In general, it was found that cool deformation improved the mechanical properties of all the steels, and the extent of these improvements was dependent on the chemical composition.
Understanding and Mitigating Under-Deposit Corrosion in Large Diameter Crude Oil Pipelines: A Progress Report
Authors: Place T. D. , Holm Michael R. , Cathrea Colin , Ignacz Tom
Published: July 2009

This paper is an exploration of factors affecting internal corrosion of transmission pipeline systems (<0.5% S&W), as well as a progress report on research aimed at improving chemical mitigation of this threat in heavy oil product streams. Typical pipeline corrodents and corrodent transport mechanisms are explored. Transmission quality hydrocarbon products are shown to carry micro-emulsified water, various solid particles, solid particles with micro-attached water, and bacteria. While micro-emulsified water can be considered benign owing its ability to be transported harmlessly without accumulation; water-wetted solid particles have sufficient density to reach the pipe floor. Patterns of internal corrosion on a transmission pipeline are used to demonstrate the significance of solids accumulation leading to under-deposit corrosion. Analysis of pipeline sludge reveals significant populations of different bacterial species indicating the existence of a robust biomass capable of creating or sustaining a corrosive environment. Corrosivity testing of pipeline sludges was performed using two static autoclave coupon methods. One test method demonstrated that the addition of chemical inhibitor directly to the pipeline sludge could reduce corrosion rates as effectively as batch treatment of a clean coupon. A rotating mechanical contactor was designed and built to facilitate the blending of corrosion inhibitor with pipeline sludge under ‘like-pipe’ flow conditions, but results of sludge corrosivity testing using this device are not yet available.
Engineering: Economic Characteristics of Hot Crude Oil Pipelines
Authors: Cui Hongsheng , Wu Changchun , Xing Xiaokai
Published: July 2009

As a well-known means for pumping crude oil with high pour point, the economic effect of a hot oil pipeline to be built will depend on such factors as pipeline capacity, pipeline length, properties of the oil to be pumped, environmental conditions along the right of way, design scheme and operation scenarios. Generally speaking, engineering-economic characteristics of oil and gas pipelines are a complete set of the economic relationships relevant to engineering factors of the pipelines, each relationship involving at least an economic index or parameter. The engineering-economic characteristics of hot oil pipelines reflect basic regularities governing the general economic effect and each economic index of the pipelines, so it is helpful understanding these characteristics for the decision-making about whether and how to build a hot oil pipeline. In some cases, for a specific hot oil pipeline project, a decision or judgment on macro level may be made only from some common engineering-economic characteristics of hot oil pipelines, without the need for the engineering design and the economic analysis of the project in detail. The frame of engineering-economic characteristics of oil and gas pipelines is outlined in this paper, and some key elements are discussed on the basis of a large amount of engineering calculation and economic analysis of virtual hot oil pipeline projects, including the optimal pipe diameter and the optimal flow velocity for a given pipeline capacity, the economic capacity limits and the economic flow velocity limits for a given pipe diameter, the economically feasible maximum pipeline length for a given pipeline capacity, and the economically feasible minimum pipeline capacity for a given pipeline length. Though the basic economic data used in our research come from China, its research results and conclusions on engineering-economic characteristics of hot oil pipelines also would be helpful for hot oil pipeline projects in other countries all over the world.
Feeler Pig: A Simple Way to Detect and Size Internal Corrosion
Authors: Camerini Claudio , von der Weid Jean Pierre , Freitas Miguel , Salcedo Thiago
Published: July 2009

Submarine pipeline inspection traditionally employs the same technologies used for onshore pipelines. One of such technologies is the instrumented pig, which usually runs under the same parameters and procedures as those used for onshore inspections. However, it is very common to find submarine pipelines with many kinds of obstacles that may prevent the use of conventional instrumented pigs, like magnetic flux leakage (MFL) and ultrasonic pigs. The relevant factors that make the inspection difficult are the different diameters along the pipeline, small radius bends, equipment installed in the pipeline (such as manifolds and valves), increased wall thickness, multiphase fluids, etc. Currently available techniques to inspect these pipelines have limitations. For ultrasonic pigs, the need of a homogeneous fluid, with good acoustic properties, to serve as sonic wave coupling is a relevant factor. On crude oil pipelines, this homogeneous fluid is not always available, as these lines carry multi-phase products. For magnetic pigs, it may not be possible to fully magnetize the heavy wall thickness pipe needed in offshore applications for structural reasons. Focusing on this context, a new tool was developed to detect and size reductions of wall thickness associated to internal corrosion. This tool, called Feeler Pig, was designed to be able to overcome diverse limitations that conventional pigs have. The Feeler Pig performs the direct dimensional measurement of pipeline internal corrosion by contact, with no practical limit of wall thickness to inspect and no need of homogeneous fluid during the inspection job. The system has been tested in field and had the performance compared to a standard ultrasonic instrumented pig. Excellent defect correlation was observed between the Ultrasonic and Feeler Pig data, not only in length and width but also in depths of internal corrosion. With this high confidence, other prototypes of Feeler Pigs were developed. One of them, named Feeler Snake Pig, was built with the installation of feeler nails into a flexible polyurethane support yielding tool with ultra high tolerance to geometric restrictions and is able to navigate through sharp bends and geometric accessories. The excellent results of the prototype and its robustness against line geometric restrictions immediately open a wide range of opportunities for the Feeler Snake Pig technology in field applications.
Stress Analysis of Pipe Lowering-In Process During Construction
Authors: Liu Ming , Wang Yong-Yi , Rogers Geoff
Published: July 2009

Stress analysis is a prerequisite of Engineering Critical Analysis (ECA) of pipeline girth welds in new constructions. Such analysis is required in pipe construction standards, such as API Standard 1104 Appendix A. However no specific procedures of stress analysis are usually prescribed in pipeline construction standards. Although the input stress for ECA is supposedly to include all stresses during the life time of the pipelines, the most significant stress is usually the stress imposed on the pipelines in the lowering-in process during construction. Various factors affecting the lowering-in stress were examined in this paper. Some of the dominant factors are the relative lift height of the pipe, cover depth, and the number of lift points. The number of lift points is related to the number of sidebooms used in construction and is determined by the diameter and wall thickness of the pipe (or pipe unit weight). The longitudinal stress is strongly affected by the number of sidebooms and the relative spacing and load distribution of the sidebooms. Practical considerations are given to the load capacity of the sidebooms and lift height variation in a pipeline construction project.
Characterization of Microstructure in High Strength Microalloyed Steels Using Quantitative X-Ray Diffraction
Authors: Li X. , Wiskel J. B. , Henein H. , Ivey D. G. , Omotoso O.
Published: July 2009

The mechanical properties of microalloyed steels used in pipelines are strongly affected by microstructure. In this paper, X-ray diffraction (Rietveld method) was used to quantify the microstructure — specifically domain size, microstrain and preferred orientation — for four X80 steels and three experimental X100 steels. Measurements were made at the surface and at several positions below the surface. Nano-sized domains were obtained for all steels tested. A smaller domain size, higher microstrain and stronger preferred orientation were observed in the X100 samples relative to the X80 steels.
Comparison of US and Canadian Transmission Pipeline Consensus Standards
Authors: Meyer Keith J. , Smith Robert W. , Murray Alan
Published: July 2009

A coordinated effort between the pipeline regulatory entities in the United States and Canada is paramount for reducing energy congestion across the border. The interconnected nature of the pipeline infrastructure in North America and the growing demand for energy in the US are clear drivers for cross border coordination and collaboration. Regulatory agency cooperation by the Canadian National Energy Board (NEB) and the US Pipeline and Hazardous Materials Safety Administration (PHMSA) recognizes this dependency and the continued safe operation and expansion of the pipeline infrastructure. To achieve these goals, much is dependent on the adequacy and effectiveness of safety and specification consensus standards covering a wide range of pipeline transportation activities. Pipeline regulations in the US and Canada rely largely on the partial or complete incorporation of industry standards by reference. The US and Canadian national pipeline regulations are compared in this paper in design and construction areas, noting the important differences.
If You Can’t See It You Can’t Detect It
Authors: Farmer Edward J.
Published: July 2009

Fundamental to all process monitoring and control is observability, the quality that the state of a system (e.g., a pipeline leaking or not leaking) is actually discernable from the measurements available. Here are four examples of how measurement issues obliterated productive monitoring. In one example a transient phase change in a process loop results in gross mis-measurement at one end. A second example illustrates that buying a flow meter does not always result in flow measurement. A third example shows a pipeline in which the readings at one end show absolutely no relationship to the other. The fourth example shows a pipeline that appears to be leaking at one end but fine at the other. The concept of observability provides some structure for thinking through these situations and developing solutions.
Morphological Development for Acicular Ferrite in High Strength Pipeline Steel Weld Metal
Authors: Komizo Yu-Ichi , Terasaki Hidenori , Yamada Tomonori
Published: July 2009

Acicular ferrite is regarded as the most desirable microstructural feature, in view of strength and toughness, in high strength pipeline steel weld metals. Recent evolution and diversity of mechanical property for base metal demand the same property as the weld. Therefore, understanding of the formation mechanism for acicular ferrite microstructure in weld is one of the essential problems for low carbon low alloy steel weld. In the present work, the morphological development of acicular ferrite in situ, was observed during weld cooling. The sample designed to form acicular ferrite microstructure was schematically heated and cooled by infrared imaging furnace and the morphological developments were directly observed using laser scanning confocal microscopy. The nucleation and growing at inclusion, sympathetic nucleation and impingement event of acicular ferrite were directly shown in high time resolution. To clarify the evolution mechanism, the inclusions related to acicular ferrite formation were investigated from the crystallographic points of view.
Modeling and Simulation of Artificial Lifting Methods on Offshore Oil Platforms
Authors: Leal Fernando I. , de O. Junior Silvio
Published: July 2009

The objective of the following paper is to present a model for the artificial lifting mechanism known generally as gas-lift and a comparison between its correlates. The comparison between lifting mechanisms can be performed directly, through experiments, or indirectly, through computational simulation. It has been chosen to develop a closer to the state-of-the-art model for the gas-lift, in order to compare it with the results of the multiphase pump simulation contained in the bibliography and included in this paper. Initially a flow pattern has been established, so that the boundary conditions would be known and the control volume would be therefore established as well; in which the intrinsic equations of the flow could be applied. Then, simplifying and adequate hypothesis were formulated, and the geometry, of the high depth riser, in which the mechanism would be simulated, was created, these were inputted into a numerical simulation CFD software. Inputting these geometrical and fluid data along with several controlling equations in the CFX® 5.7 software demonstrated the behavior of the gas lift, both in the transient, as an illustration, and in the steady state flow, and permitted an evaluation and graphical analysis of relevant parameters of the gas lift mechanism. Finally a comparison, between the results obtained by the SMPS (Submarine Multiphase Pumping System) and the above has been performed, showing in which situations the mechanisms presented a higher performance in a real high depth offshore well located in the Campos Basin, Rio de Janeiro.
Fatigue Life Analysis of Steel Pipelines With Plain Dents Under Cyclic Internal Pressure
Authors: de Carvalho Pinheiro Bianca , Pasqualino Ilson Paranhos , da Cunha Se´rgio Barros
Published: July 2009

This work is within an ongoing study, which aims to propose a new methodology for fatigue life analysis of steel pipelines with plain dents under cyclic internal pressure. This methodology follows the current high cycle fatigue theory and employs stress concentration factors induced by plain dents to modify standard S-N curves. A previously developed and validated finite element model is extended to generate stress concentration factors for longitudinal and transverse dents, in addition to spherical dents. Several finite element analyses are carried out in a parametric study to evaluate stress concentration factors induced by the three dent types studied: spherical, longitudinal and transverse dents. Analytical expressions are developed to estimate stress concentration factors for these three dent types as function of pipe and dent geometric parameters. Small-scale fatigue tests are conducted to evaluate the finite life behavior of dented steel pipes under cyclic internal pressure. The methodology is validated in view of the fatigue tests results. Including expressions to estimate stress concentration factors for three different dent types (spherical, longitudinal and transverse dents), the proposed methodology can then be used for fatigue life analysis of dented steel pipelines under cyclic internal pressure.
Supervision During Commissioning Procedure for Commercial Operation of 32 MW Turbogas Power Plants
Authors: Pe´rez Rodri´guez Norberto , Rosado Tamariz Erik , Illescas Rafael Garci´a
Published: July 2009

This article presents the supervision and testifying process during the start of commercial operations of several turbogas plants generating electricity rate of 32 MW each fuelled by natural gas. Supervision and testifying process were conducted at the request of the customer to confirm and observe that the evidence of commissioning, testing and operation of acceptance tests were carried out as specified by international regulations, calling the outcome of each tests agree the applied rules. The work was done in collaboration with the supplier and manufacturer of equipment, the client and the institution responsible for certification and approval of the plant. All this according to a logical and chronological order for the sequence of tests commissioning, operation and acceptance. Tests for putting into service are carried out on-site at normal operating conditions, according to the design and operation needs of the plant. Once implemented in full and in a satisfactory manner, test operation of each plant was carried out considering that they must operate automatically, reliable, stable and secure, fulfilling at least, one hundred hours of operation at full load. After completed operation tests are conducted, acceptance testing on the power plant and integrated approach to assessing the quality of the product were accomplished. Finally, it was verified if each unit meets the technical requirements established in terms of thermal capacity of the machine, noise levels and emissions. As a result of this supervision and testifying process, it is guaranteed to the client that the power plants and all their equipment, comply with the requirements, conditions and specifications in agreement with the supplier, concerning test of putting into service, operational and acceptance tests.
High Efficiency Renewable Energy From Residual Materials
Authors: Paisley Mark A. , Page Allan
Published: July 2009

Recent price increases for various forms of energy along with projected shortages of supply have resulted in renewed interest in alternative fuels. Biomass gasification provides a renewable basis for supplying electric power and also a broad suite of chemicals such as Fisher-Tropsch liquids as well as hydrogen. The Taylor gasification process, being developed by Taylor Biomass Energy is a biomass gasification process that produces a medium calorific value (MCV) gas. The Taylor gasification process provides improvements over currently available gasification processes by integrating improvements to reduce issues with ash agglomeration and provide in-situ destruction of condensable hydrocarbons (tars), an essential element in gas cleanup. The gas conditioning step integrated into the Taylor Gasification Process provides a unique method to convert the tars into additional synthesis gas and to adjust the composition of the synthesis gas. Taylor Biomass Energy has developed and refined a sorting and recycling process that can produce a clean feedstock for energy recovery from abundant residue materials such as construction and demolition residuals and municipal solid wastes (MSW). The sorting and separating process can then be coupled to the Taylor gasification process to produce clean, sustainable energy. The development process including integration with a gas turbine based combined cycle system, connection into the New York ISO, and identification of renewable energy credit options is discussed along with a discussion of the Taylor Gasification Process, its modular design, and implementation into the commercial Biomass Integrated Gasification Combined Cycle (BIGCC) system in Montgomery, NY.
Monitoring of Impulse Line Blockage Using Phase Difference Between Upstream and Downstream Pressures of Orifice
Authors: Eino Jyun-Ichi , Uehara Akira , Wakui Tetsuya , Hasizume Takumi , Miyaji Nobuo , Yuuki Yoshitaka
Published: July 2009

The combination use of a differential pressure transmitter, orifice and impulse line to produce a flowmeter is widely used in the process industries. Since the most frequent problem encountered in the usage of this flowmeter is impulse line blockage, an online blockage detection system is required. In previous works, the authors developed an indicator of impulse line blockage, called the blockage index, which is based on pressure fluctuations. Although the blockage index is able to detect the blockage effectively without being affected by the change in the flow rate and pressure, it can not detect the blockage as the rate of line pressure change increase. In addition, there are continuous and frequent line pressure changes in certain applications. Hence, the objective of this study is to detect impulse line blockages even when the line pressure change rate is so high that the blockage index is unable to detect the blockage. In this paper, the authors present details on the delay in the pressure transmission caused by the blockage, and evaluate the delay quantitatively by using the phase difference between the pressure upstream and downstream of the orifice as a new blockage index. In addition, by selecting frequencies with high power spectral densities, the new index becomes sensitive enough to detect the blockage during the more rapid line pressure changes under which the former blockage index failed.
Important Concepts of Wet-Limestone Flue Gas Desulfurization
Authors: Buecker Brad
Published: July 2009

Many utilities are installing wet flue gas desulfurization (FGD) systems to comply with tighter sulfur dioxide regulations. These installations will introduce many utility engineers and other technical personnel to a sometimes complex air pollution control technology. This paper outlines fundamental concepts of wet limestone FGD, particularly in the most common design, spray towers. Topics will include liquid-to-gas ratio, chemistry operating parameters, limestone grinding and classification, materials selection for a rugged environment, byproduct disposal, and scrubber performance monitoring. The paper will also briefly review cutting-edge alternatives to spray towers.
Rotor Winding Shorted Turn Detection: Detection of a Turn Short Associated With a Generator Condition Monitor Alarm
Authors: Albright David J.
Published: July 2009

The use of air-gap magnetic flux probes has proven effective in the detection of generator rotor winding shorted turns and has helped to improve the quality of predictive maintenance decisions concerning when or if to perform rotor rework. Analysis of air-gap flux probe data can pinpoint the number and location (pole and coil) of shorted turns while the generator is running at normal operating loads. This allows the identification of shorted turns which may not be detectable when the unit is offline since the operating centrifugal and thermal forces are not in effect at standstill. A recent case history shows the development of a turn short in a large two-pole generator rotor that was signaled by a generator core monitor (GCM) alarm. The GCM provided a 5–10 minute alarm that was immediately followed by a significant increase in rotor bearing vibration. Testing of the unit showed that the higher vibration levels were thermally sensitive. Flux probe testing showed the development of an unambiguous turn short in one of the #3 coils.
After FMECA: Using Vulnerability to Establish a Technical Basis for Maintenance Tasks
Authors: Thibault Justin
Published: July 2009

Increasing demands on maintenance and operations organization are coupled with the loss of expertise industry-wide — causing many organizations to approach plant maintenance more reactively in spite of past investments in Reliability-Centered Maintenance (RCM) efforts — including Failure Mode Effects and Criticality Analysis (FMECA). This phenomenon is known as degradation of the maintenance basis. The Electric Power Research Institute (EPRI) has developed a method to maintain the investments utilities have made into various maintenance optimization efforts. Utilizing expert elicitation, EPRI has developed modules for 136 different components and a statistical method for measuring degradation and task effectiveness data for each component and rolling those results to the system and the plant level. The end result of a successful analysis is a technical basis for maintenance that is established using quantitative analysis on proven data. This paper will describe a method for vulnerability-based analysis.
CFD-Based Energy Improvement of a Parametric Blade Model for a Francis Turbine Runner
Authors: Franco-Nava Jose´ Manuel , Rosado-Tamariz Erik , Ferna´ndez-Da´vila Jose´ Manuel , Rangel-Espinosa Reynaldo
Published: July 2009

The computational fluid dynamic (CFD) based energy improvement of the parametric blade model for a Francis turbine runner is presented. The evaluation of the energy improved uses the results of CFD based optimization of a hydraulic Francis turbine runner. The parametric runner model used by the CFD based optimization process was obtained by applying a parametric blade modeller for turbomachinery based on a geometric reference model. This parametric runner model and the optimization process were computed by using a three dimensional Navier-Stoke commercial turbomachinery oriented CFD code. The flow within hydraulic turbines has a thin boundary layer and noticeable pressure gradients. Hence, the CFD computations were carried out using the Sparlat-Allmaras turbulence model. The aim of the optimization process was improve the performance of the machine. This process was computed by a CFD code integrated environment which combines genetic algorithms and a trained artificial neural network. After optimization cycle convergence, an increment not only in efficiency but also in power was obtained. The energy that is transferred to the runner blade and transformed in torque and power was obtained by using CFD results. From pressure distribution along the normalized arc length of the runner blade for three operating conditions (100%, 85% and, 75% of load) the energy distribution was computed not only for the reference runner but also for the optimized parametric model of the turbine runner. Finally, the averaged energy saved for the same operating conditions was evaluated. Results have shown that application of CFD based optimization can modify and improve runners design so as to increase the efficiency and power of installed hydraulic power stations.
Advances in Direct Measurement of Gas Turbine Exhaust Temperature With Multi-Element Thermocouple Rakes for Diagnosing Performance Issues and Characterizing Turbine Upgrades
Authors: Schmitt Thomas P. , Banares Christopher R. , Clement Herve , Gsell Joshua D.
Published: July 2009

Heavy-duty gas turbines are designed to deliver maximum performance within their respective technology class and emissions limits. In order to achieve performance goals consistent with hot section durability constraints, it has become more critical than ever for engineers to have an economical, dependable, and accurate measurement of the average exhaust gas temperature and the associated profiles. Simple thermocouples “rakes” have been used for many years to meet the basic need of measuring planar average temperature. In addition, recent testing experience has shown that the measured radial temperature profile data from these same “rakes” can play a key role in the diagnosis of performance issues and also in the characterization of hardware upgrades. For example, high technology hot section spin-offs from F, G, and H class turbines have been applied as upgrades to older B and E class turbines with dramatic impact on the exhaust temperature pattern. Another example has been the use of pressure/temperature exhaust “rakes” in F class turbines to diagnose changes in the radial temperature profile that result from combustion system upgrades. In both cases, the careful measurement and interpretation of these temperature patterns is crucial to the proper setting of control algorithms that govern performance levels and exhaust emissions. Advances in the design and arrangement of exhaust thermocouple rakes, and in the analysis methods used to interpret the resultant test data, are presented. Several recent cases of using rakes to diagnose performance issues and to characterize the temperature pattern for the purpose of optimizing control settings are discussed.
Vibration Monitoring System Integrity Subtly Affects Vibration Symptoms and Impacts Machinery Malfunction Diagnosis
Authors: Endres Ned M.
Published: July 2009

Proper installation and functionality of a rotating machinery protection and monitoring system is essential for accurate diagnosis of machinery related malfunctions. For some gas turbine driven generator units, some monitoring system components can be internal to the machine and somewhat inaccessible. Monitoring system component problems and failures can result in obvious symptoms; however in a few instances these symptoms can be subtle and lead to a false or inappropriate malfunction diagnosis. These false diagnoses can result in unnecessary corrective actions in instances that required only simple “fixes”. Proper installation and functionality of a rotating machinery protection and monitoring system is essential for accurate diagnosis of machinery related malfunctions. For some gas turbine driven generator units, some monitoring system components can be internal to the machine and somewhat inaccessible. Monitoring system component problems and failures can result in obvious symptoms; however in a few instances these symptoms can be subtle and lead to a false or inappropriate malfunction diagnosis. These false diagnoses can result in unnecessary corrective actions in instances that required only simple “fixes”. This paper will discuss a recent case history involving chronic excessive vibration alarms and trips at a customer’s facility. Acquired vibration readings will be discussed. These measurements will illustrate the effects of subtle monitoring system component issues on machinery vibration levels leading to a potentially false diagnosis. Proper interpretation resulted in a correct diagnosis, thus avoiding unnecessary corrective actions.
ASME PTC 19.5 Procedures for Application of Laboratory Calibrations of Differential Pressure Flow Meters
Authors: Friedman Jeffrey R. , Keyser David
Published: July 2009

Performance Test Codes require primary mass flow accuracies that in many applications require the laboratory-quality calibration of differential pressure meters. It is also true that many performance tests are conducted at Reynolds numbers and flows well above the laboratories’ capacities, and sound extrapolation methods had to be developed. Statistical curve-fits and regression analyses by themselves, absent fluid-dynamic foundations, are not valid procedures for extrapolation. The ASME PTC 19.5-2004 discharge coefficient equations presented in this paper are suitable for use and extrapolation of laboratory calibration data.
Changing Tube Materials: Thermal Calculations for Material Change When Re-Tubing
Authors: Bruno Joseph A. , Muldoon Thomas J.
Published: July 2009

The challenge of plant engineers, operators, and chemical engineers is to select a tube material for various heat exchangers in nuclear or fossil power plants that will survive various and possibly changing fluid chemistries. This paper will provide a brief method of calculating the effect of changing materials when retubing a heat exchanger. It will also provide some samples of typical effects.
Application of New Individual Condenser Tube Circulating Water Flow and Fouling Meter in Performance Monitoring and Troubleshooting: A Case Study
Authors: Harpster Timothy J. , Harpster Joseph W. , Shah Sunish , Weber Gerald , Horn Michael
Published: July 2009

Low cost, reliable and accurate real time measurement of individual tube condenser cooling water flow rate, cooling water outlet temperature and tube side fouling for the purpose of condenser performance monitoring and troubleshooting is presented. The importance and the effects of these parameters on condenser performance are well understood and periodically estimated using indirect measurements such as dye dilution testing to represent average tube circulating water velocities, distributed temperature sensors in waterboxes and differential pressure measurements between inlet and outlet waterboxes. These measurements, while useful, are not always effective to identify performance inhibiting issues quickly and accurately. This paper presents a cooperative study on the effects of circulating water flow and fouling and protective tube coatings for the purpose of condenser performance and monitoring improvement. The objective of the study was to evaluate new Circulating Water Flow and Fouling (CWFF) instrumentation [1], [2], [3] to evaluate impact of tube coating [4] on heat transfer and biofouling, and to examine the effect of other variables on on-going Microbiologically Influenced Corrosion (MIC) attack on the SS condenser tubes. However, in addition to providing useful information on the coated tubes, the study unveiled a number of other condenser performance related issues. Real-time in-situ circulating water flow and fouling data over an entire 1-year period will be presented that: • Correlates real-time flow measurements to fouling as it occurs; • Assists in the evaluation of different circulating water pump capacities and configurations; • Identifies flow stratification within the water box and identifies whether or not waterboxes are filled; • Evaluates the heat transfer coefficient differences between the coated and uncoated tubes; • Identifies other performance related findings.
Improved System of a Braking Lever Transmission for Rail-Cars
Authors: Sharashenidze Guri , Mgebrishvili Nikoloz , Nadiradze Tengiz , Kurtanidze Pavle
Published: July 2009

Operating lifetime of rail-cars greatly depends on fitness of braking systems and on effectiveness of their constructions. Various braking systems are being elaborated in this trend where lever transmissions are used. Designing of a braking lever transmission for rolling stocks is a very urgent problem. A transmission should be simple and should contain minimum number of levers and hinges. Increased reliability and operating lifetime of braking lever transmissions for rail-cars are achieved in the work. A new construction of rail-car braking lever transmission is elaborated where number of levers and braking joints are decreased significantly and it ensures increase of traffic safety and economic efficiency. A calculating dynamic model of a new construction is elaborated in the work, which obey the basic provisions of mathematical analysis. Dynamical loads in joints of the construction are calculated taking into account increased wear and stresses. Accomplished work provides with possibility for solution of urgent problems. Introduction of the mentioned construction will significantly increase reliability and operating indices of modern rail-cars.
The Effects of Wheelset Position and Operating Environment on Rolling Contact Fatigue
Authors: Cummings Scott M. , Krupowicz Paul
Published: July 2009

The Wheel Defect Prevention Research Consortium (WDPRC) conducted analyses of wheel impact load detector (WILD) data to explore how wheelset position and operating environment affect rolling contact fatigue (RCF). The typical three-piece freight car truck used in North America produces higher tangential wheel/rail contact forces on the wheelset in the lead position than on the wheelset in the trail position of a truck as a car negotiates a curve. An analysis of WILD data shows that these higher forces are contributing to more shelling damage on wheelsets that are consistently in the lead position of a truck. Datasets in which the cars are frequently oriented with the A-end leading show the largest percentage of elevated WILD readings in the lead position of the lead truck (axle 4) followed by the lead position of the trail truck (axle 2). Likewise, datasets in which the cars are frequently oriented with the B-end leading show the largest percentage of elevated WILD readings in the lead position of the lead truck (axle 1) followed by the lead position of the trail truck (axle 3). Additionally, datasets in which there is an equal mix of car orientations show a much more evenly distributed location of elevated WILD readings. Another analysis of WILD data from five trainsets of nearly identical cars shows that any differences in wheel tread damage due to component differences are insignificant in comparison to the differences in wheel tread damage associated with environmental factors. While this analysis does not address component specification differences that could potentially have a large influence on shelling (such as M-976 trucks in comparison to standard trucks), it does show that environmental factors can play a large role in wheel tread damage. Car routing and loading characteristics were investigated as possible wheel damage factors. It appears that cars running on routes through terrain with longer, steeper grades may be prone to increased wheel shelling, probably due to thermal mechanical shelling (TMS). Side-to-side imbalanced loading appears to play a minor role in wheel shelling for two of the five trainsets.
The Use of Automated Rail Vehicle Inspection Systems (ARVIS) at NJ Transit
Authors: Fry Kevin , Bloom Jeff
Published: July 2009

To promote the reliability of its fleet of rail cars and to move toward a condition-based maintenance approach, NJ Transit has launched a pilot program in which Automated Rail Vehicle Inspection Systems (ARVIS) are being used to complement visual inspections of brakes and wheels on a range of fleet vehicles. NJ Transit contracted the UK firm DeltaRail to design, build and install three ARVIS installations at its new Morrisville, PA maintenance facility and to support them during a two-year trial. DeltaRail has installed a number of similar systems in Europe over the past 10 years, but the NJ TRANSIT project is the first example of ARVIS technology being put to use in the western hemisphere. To provide local support DeltaRail worked with ENSCO as its US partner on this project. The installation at Morrisville comprises three identical ARVIS systems covering all entry tracks into the yard. Each trackside system measures wheel profile, axle-mounted disc brake pads, wheel-mounted disc brake pads, tread brake shoes and wheel roundness. A total of 36 cameras (12 for each system) are used, making this the world’s largest automated visual inspection system for rail vehicles. The system became operational in April 2008. The measurement information and images from each trackside system is sent by a high-speed communications link to an ENSCO-hosted data server. The measurements for every component are added to an Information Display System, which builds historic wear trends, predicts remaining component life and highlights problems causing abnormal wear rates. Access to the information is available globally through a secure internet account. It is anticipated that the data from ARVIS will provide a better understanding of the current and future state of equipment. This predictive information will improve management by reducing maintenance costs, increasing maintenance efficiency, improving safety, optimizing associated consumable costs and demonstrating compliance with standards to regulatory bodies. Additionally, the potential exists to reduce the frequency of manual inspections in the hazardous areas beneath trains while still meeting all FRA inspection requirements, allowing maintenance staff to concentrate their efforts on repairs. This paper describes the installed systems, shows some of the initial results and discusses how the information will be used to deliver the expected benefits.