bluuebunny/crossref_metadata_2025 huggingface dataset:
Two-Phase Flow Distribution in a Compact Heat Exchanger Header
Authors: Kim Jong-Soo , Im Yong-Bin , Kim Jae-Hong , Lee Ki-Taek
Published: March 2009

In this paper an experimental study was investigated for two-phase distribution in compact heat exchanger header. A test section was consisted of the horizontal header (circular tube: φ 5 mm × 80 mm) and 10 upward circular channels (φ 1.5 mm × 850 mm) using acrylic tube. Three different types of tube insertion depth were tested for the mass flux and inlet quality ranges of 50–200 kg/m2s and 0.1–0.3, respectively. Air and water were used as the test fluids. The distribution of vapor and liquid is obtained by measurement of the total mass flow rate and the calculation of the quality. Two-phase flow pattern was observed, and pressure drop of each channel was measured. By adjusting the insertion depth of each channel a uniform liquid flow distribution through the each channel was able to solve the mal-distribution problem.
Analogy Between Heat Transfer and Fluid Friction of Gas-Liquid Two-Phase Flow in Minichannel
Authors: Kaji Masuo , Sawai Toru , Mori Koji
Published: March 2009

To investigate the analogy between heat transfer and fluid friction of two-phase flow in minichannel, heat transfer coefficient, pressure drop and void fraction were simultaneously measured for vertical upward heated air-water two-phase flow in a 2.01 mm I.D. stainless steel tube. Void fraction was slightly different from Smith’s correlation and drift flux model, but the latter gave fairly good prediction when α>0.8. Frictional pressure losses were greater than the experimental results of Mishima-Hibiki for a 2.05 mm I.D. Pyrex glass tube and the correlation of Chisholm-Laird. Heat transfer coefficients agreed with our previous experimental results for a 8.03 mm I.D. tube. A theoretical calculation was performed for an annular liquid film flow model using experimental values of wall shear stress and liquid holdup, and satisfactory results were obtained except when the liquid flow rate was very low.
Flow Boiling of R-134a in Minichannels With Transverse Ribs
Authors: Molki Majid , Mahendra Pranay , Vengala Venugopal
Published: March 2009

An experimental effort was undertaken to investigate the flow boiling of R-134a in minichannels with transverse ribs. The test channel consisted of two parallel plates; the lower plate was heated while the upper plate was adiabatic and fabricated from a clear material to facilitate the visualization and photography of the boiling process. A number of transverse ribs were deployed along the lower plate to form a meandering flow passage inside the minichannel. The ribs blocked 3/4 of the flow cross-section in the transverse direction and the hydraulic diameter of the channel was 1.93 mm. In these experiments, the range of test parameters were: mass flux 100 to 225 kg/m2s, saturation temperature 15 to 30°C, heat flux 14 kW/m2, and average vapor quality 0.12 to 0.86. With these parameters, the Convective and Boiling numbers ranged from 0.04 to 0.90 and 7.49 × 10−4 to 8.98 × 10−4, respectively. Of a total of 60 data points recorded, 78% of the data fell in the convective boiling region, while the remaining 22% were in the nucleate boiling region. In an attempt to model and correlate the data, it was found that the Kandlikar’s correlation proposed for augmented tubes was a suitable model for the present minichannel. Using the least-squares procedure, this two-equation model was fit to a total of 60 experimental data, resulting in a correlation that predicted 58 data points to within ±10%.
Flow Boiling Heat Transfer of R-22 in Small-Diameter Horizontal Round Tubes
Authors: Park K. S. , Choo W. H. , Bang K. H.
Published: March 2009

The flow boiling heat transfer coefficient of R-22 in small hydraulic diameter tubes has been experimentally studied. Both brass and aluminum round tubes of 1.66 mm inside diameter are used for the test section. The ranges of the major experimental parameters are 300∼600 kg/m2s of refrigerant mass flux, 10∼20 kW/m2 of the wall heat flux, 0.0∼0.9 of the inlet vapor quality. The experimental result showed that the flow boiling heat transfer coefficient in this small tubes are in the range of 2∼4 kW/m2K and it varies only by heat flux, independent of mass flux and vapor quality. It is also observed that the heat transfer coefficients in the aluminum tube are up to 50% higher than in the brass tube.
Two Large-Amplitude/Long-Period Oscillating Boiling Modes in Silicon Microchannels
Authors: Wu H. Y. , Cheng Ping
Published: March 2009

A simultaneous visualization and measurement study has been carried out to investigate flow boiling of water in the 8 parallel silicon microchannels heated from below. It is found that there are two large-amplitude/long-period oscillating boiling modes exist in microchannels depending on the amounts of heat flux and mass flux. When the outlet water temperature is at saturation temperature and the wall temperatures are superheated, while the inlet water temperature is still subcooled, a Liquid/Two-phase Alternating Flow (LTAF) mode appears in the microchannels. This LTAF mode disappears when the inlet temperatures reaches the saturation temperature. As the heat flux is further increased such that the outlet water is superheated while the inlet water temperature is oscillating between subcooled and saturation temperature, a Liquid/Two-phase/Vapor Alternating Flow (LTVAF) mode begins. During these two unstable boiling modes, there are large-amplitude and long-period oscillations of water and wall temperatures with respect to time. Bubbly flow as well as some peculiar two-phase flow pattern are observed during the two-phase flow periods of the two unstable modes in the microchannels.
Maximum Heat Transfer Rate Density in Two-Dimensional Minichannels and Microchannels
Authors: Favre-Marinet M. , Le Person S. , Bejan A.
Published: March 2009

Experimental investigations of the flow and the associated heat transfer were conducted in two-dimensional microchannels in order to test possible size effects on the laws of hydrodynamics and heat transfer and to infer optimal conditions of use from the measurements. The test section was designed to modify easily the channel height e between 1 mm and 0.1 mm. Measurements of the overall friction factor and local Nusselt numbers show that the classical laws of hydrodynamics and heat transfer are verified for e > 0.4 mm. For lower values of e, a significant decrease of the Nusselt number is observed, whereas the Poiseuille number continues to have the conventional value of laminar developed flow. The transition to turbulence is not affected by the channel size. For fixed pressure drop across the channel, a maximum of heat transfer rate density is found for a particular value of e. The corresponding dimensionless optimal spacing and heat transfer rate density are in very good agreement with the predictions of Bejan and Sciubba (1992). This paper is the first time that the optimal spacing between parallel plates is determined experimentally.
Analysis of Flow Resistance Inside Microchannels With Different Inlet Configurations Using Micro-PIV System
Authors: Lee Sang-Joon , Kim Guk-Bae
Published: March 2009

Most microfluidic chips consist of several microchannels inside. In order to design microfluidic chips efficiently, it is important to predict the flow passage and to understand the flow characteristics on the chip. In this study, the flow structure inside microchannels has been investigated using a micro-PIV system. We focused on the flow resistance with respect to the inlet configuration of microchannels. The microchannels made of poly-dimethyl-siloxane (PDMS) material were fabricated by a micro-molding technique using SU-8 (photoresist) master. The width (w) and depth of the microchannels were fixed as 100 μm and 58 μm, respectively. Six different inlet configurations with curvature radii in the ranges from r = 0.2w to 1.5w were tested in this study. As a result, with increasing the curvature radius of the inlet corner, the streamwise mean velocity develops slowly in the entrance region, but the fully developed velocity at further downstream is increased. When the curvature radius is larger than r = 0.6w, the reduction rate of flow resistance is not so significant. For the microchannels with r = 0.6w, 0.8w and 1.0w the downstream mean velocity at channel center has nearly the same value of about 276 mm/sec, 10.5% larger than that of r = 0.2w. The simple rounding of microchannel inlet corner reduces flow resistance effectively by smoothing the incoming flow. The length of entrance region is much smaller than that of macro-scale channel.
Weak-Link Analysis of Motor-Operated Butterfly Valve
Authors: Kim Donghae
Published: March 2009

The purpose of this paper is to address the structural integrity of the motor operated butterfly valve assembly by providing the methodology and equations to quantitatively determine the permissible component load in the load path from the operator to the valve. The weak link analysis is to determine the maximum allowable torque on the butterfly valve by equating the stresses caused by the torque and seismic load with the appropriate allowable stress value, and then the unknown torque is solved. Analysis methods are based on classical static force balancing equations and on classical axial, shear, and bending stress equations using the worst possible load combinations including seismic loads resulting from design basis earthquake.
Numerical Simulation of Low Heating Value Fuel Turbulent Diffusion Combustion
Authors: Arai Norio , Yamamoto Takahisa , Furuhata Tomohiko
Published: March 2009

In this study, in order to obtain fundamental data for designing the practical gas turbine combustors in the chemical gas turbine (Ch/GT) combined cycle system and/or other gas turbine systems which utilize low heating value fuel such as coal and biomass gasification syngas, we have simulated low heating value fuel–air turbulent diffusion combustion. The simulated results for the profiles of temperature and species concentrations have been compared with the measured ones. As a reaction model, the flamelet model has been applied to predict the turbulent diffusion combustion characteristics. A flamelet library which indicates relationships for scalar dissipation rate, mixture fraction, and mass fraction of chemical species were given by the calculated results of counterflow diffusion flame using 16 chemical species and 25 elementary reactions. Clipped Gaussian and a log-normal distribution were employed as the PDFs of the mixture fraction and the scalar dissipation rate, respectively. In this model, the k-ε two equations turbulence model is used to describe the turbulent flow field and the radiative heat transfer is calculated by the six-flux model. The governing equations were solved iteratively by the SIMPLE algorithm. By the comparisons of the simulated and measured results, it was clarified that the simulated profiles conformed fairly well to the measured ones in the turbulent combustor, and that this combustion simulation model could predict the low heating value fuel turbulent diffusion combustion characteristics.
CAREM-25: Energy and Safety for the Future
Authors: Pomier Ba´ez La´zaro E.
Published: March 2009

The CAREM-25 is an advanced small nuclear power plant being jointly developed by CNEA (Comisio´n Nacional de Energi´a Ato´mica) and INVAP S. E. in Argentina. CAREM is a modular 100 MWt pressurized water reactor with integral steam generators designed to be used for electricity generation (25 MWe) or as a research reactor or for water desalination. The plant has its entire primary coolant system within the reactor pressure vessel (hence ‘integral’ PWR), self-pressurized and relying entirely on natural convection. Fuel is standard 3.4% enriched PWR fuel, with burnable poison, and is refueled annually. It is a mature design, which could be deployed within a decade. The CAREM reactor shows itself as a design capable to fill the existing gap between a research reactor and a full-scale commercial nuclear power plant. From this point of view, CAREM is a very attractive option for countries who have not yet developed technical capabilities, human resources, and an industrial infrastructure needed for a medium or large size nuclear units. Advanced nuclear reactor designs, such as the CAREM reactor, include several improvements related to safety issues either enhancing the passive safety functions or allowing plant operators more time to undertake different management actions against radioactive releases to the environment The enhancement and development of safety measures for this type of system are a top priority of designers. In the development of the nuclear power plant CAREM, the possibility of including a passive metallic in-vessel container in its design is being considered, to arrest the reactor pressure vessel meltdown sequence during a core damaging event, and thereof prevent its failure. The present paper will provide an overview of the CAREM-25 technology as a general purpose generation unit, and highlight the work on safety measure’s enhancements, including design modifications aiming to improve overall safety targets of the plant.
Full Scale Burst Test and Finite Element Analysis on Corroded Gas Pipeline
Authors: Kim Woo-Sik , Kim Young-Pyo , Kho Young-Tai , Choi Jae-Boong
Published: March 2009

Pipelines have the highest capacity and are the safest and least environmentally disruptive way for gas or oil transmission. Recently, failures due to corrosion defects became of major concern in maintaining pipeline integrity. A number of solutions have been developed for the assessment of remaining strength of corroded pipelines. However, these solutions are known to be dependent on material properties and pipeline geometries. In this paper, a Fitness-For-Purpose (FFP) type limit load solution for corroded gas pipelines made of X65 steel is proposed based on experimental results and finite element analyses. For this purpose, a series of burst tests with various types of corrosion defects was performed. Finite element simulation was carried out on burst test to derive failure criteria. And then, a series of finite element analyses were performed to obtain a limit load solution for a single corrosion defect on the basis of burst test simulation. As a result, an FFP type limit load solution for corroded X65 gas pipelines was proposed.
An Effective and Proven Technique for Continuous Detection and Location of Third Party Interference Along Pipelines
Authors: Jaffrey D. , Lubbers J. , King B. , Tapanes E. E.
Published: March 2009

The potential benefits of deploying an effective integrity monitoring system on pipelines are well understood. FFT has just released a significant/new, cost-effective third party interference (TPI) detection system specifically designed for the pipeline industry. It employs patented fibre optic sensors and propriety software to give real-time, full-time protection against all forms of third party interference over the whole length of the pipeline. It detects the location of each intrusion event to within 50 m, no matter how long the pipeline is. To our knowledge, there are no other systems available with the combined features of our system.
Integrity Evaluation of an Older Vintage ERW Pipeline
Authors: Rogers Geoff B. , Rapp Steve C. , Matocha Garry M.
Published: March 2009

As part of a program to increase the operating pressure of a 20” (508.0mm) natural gas pipeline, a careful plan was developed and executed to ensure the integrity of the pipeline. The pipeline was built in 1943 using linepipe produced having a DC ERW longitudinal seam weld and travels along a densely populated route in the suburbs of Philadelphia. The work plan included ILI inspection methods to detect corrosion (MFL tool), mechanical damage (geometry tool), and ERW seam weld defects (TFI MFL tool). After the anomalies were identified and the necessary pipe replacements were completed, the pipeline was hydrostatically tested prior to being returned to service at the newly established operating pressure. The paper will describe the project planning process used to ensure the fitness and reliability of the pipeline and provide a review of the ILI results, excavations, pipe replacements, and hydrostatic test experiences. Of particular interest were the capabilities and limitations of the TFI tool to detect, discriminate, and size ERW seam weld defects. Seam weld defects were evaluated using ILI inspection methods and in many cases field prove-up ultrasonic inspection methods. When an ERW defect was confirmed by field NDT prove-up, the pipe section was removed and metallographic work was conducted to characterize the ERW flaw size and nature. A correlation was then possible between the sizing capability of the TFI tool, the ultrasonic prove-up method, and the actual defect size. All this information is useful to establish a level of confidence in defect sizing for future project needs. The final validation of the pipeline fitness at the higher operating pressure was established through the successful hydrostatic test. A short summary will be given on how the pipeline fitness was qualified and demonstrated.
Utilization of Value Improving Practices (VIPs) on Pipeline Projects
Authors: Ruthven Chris , Stripling Travis E. , Hertz Darryl W.
Published: March 2009

Value Improving Practices (VIPs) are formal structured processes applied to capital projects and operating facilities to improve profitability or value above that attained through good engineering and project management practices (Reference [1]). VIPs are most commonly applied to projects resulting in chemical processing facilities, but not so frequently applied to cross-country pipeline projects. Based upon the authors’ experiences, this paper will describe the practical application of VIPs on pipeline projects and the significant benefits that may be expected. More specifically, the following fourteen (14) Kellogg Brown & Root (KBR) project VIPs will be discussed as to their exact purpose, and how and when they should be applied during the pipeline project life cycle: 1. Setting Business Priorities and Classes of Facility Quality; 2. Technology Selection; 3. Process Simplification; 4. Customization of Standards & Specifications; 5. Constructability; 6. Design to Capacity; 7. Waste Minimization; 8. Predictive Maintenance; 9. Process Reliability Simulation; 10. Energy Optimization; 11. Value Engineering; 12. Commissioning & Startup Planning; 13. Shared Learning; 14. 3D-CAD. This paper will continue with a more in depth discussion of two VIPs that have major applicability on pipeline projects: Technology Selection and Constructability. The relationship of the VIPs with BP’s Pipeline Cost Reduction Project will also be discussed.
An Experimental Approach to Evaluate the Resistance of Gas Pipeline to Dent and Gouge Damage by an Excavator
Authors: Mannucci Gianluca , Guagnelli Mauro , Vittori Osvaldo , Spinelli Carlo
Published: March 2009

An experimental methodology for the evaluation of the resistance of gas pipeline with regard to the third part aggression by an excavator is presented. The essential tool used is a new full-scale facility specifically designed to be able to reproduce, in full-scale conditions, the external mechanical damage caused by concentrated loads, both static and dynamic, due to an excavator acting on pipelines for gas transportation. The main characteristics of the facility are: • computer controlled with the possibility to insert stiffness feedback control to simulate different excavators; • trajectory in vertical plane defined by the user via computer; • trajectory in transverse plane defined by the user using springs with stiffness simulating different excavators; • use of real excavators tooth as aggression tool; • pressurised or unpressurised test pipe. The aim of the presented experimental methodology is to demonstrate the capability to reproduce “real” excavator damage under controlled laboratory conditions starting from few, simple and basic information such as excavator type and characteristics, tool type, digging modality and relative position between excavator and pipe.
Theoretical and Experimental Study of Compressor and Gas Turbine Performances With Wet Compression
Authors: Wang Yunhui , Zheng Qun , Sun Yufeng , Wang Guoxue
Published: March 2009

Theoretical and experimental study of compressor and gas turbine performance with wet compression has been carried out on S1A-02 industrial gas turbine to reveal its effects on gas turbines, compressors. Experiment results show that wet compression has significantly effects on performances of gas turbines and compressors; under situations of high ambient temperature, wet compression can be used to restore engine power output.
Environmental Mitigation Associated With the Installation of a Natural Gas Pipeline in the Vicinity of an Artesian Well
Authors: Buszynski Mario E.
Published: March 2009

In the fall of 2001, Enbridge Consumers Gas proposed to install a 190 mm extra-high pressure steel pipeline in proximity to an artesian well on the Oak Ridges Moraine in southern Ontario. This well is located within the Regional Municipality of Durham and it is used by over 300 persons per day as their drinking water source because of very high water quality. Potential impacts to drinking water quality have taken on greater importance because of the Walkerton tragedy, in which a number of people died from drinking contaminated municipal water. The Region of Durham was especially concerned because of the large number of people who use this artesian well as their drinking water source. The Region did not want to close the well during construction as this could be taken as an admission that construction might negatively impact water quality. At the same time, they wanted to ensure that water quantity and quality was maintained. SENES Consultants Limited (“SENES”) was retained to develop and implement an environmental management plan to ensure that no negative impacts would occur during construction. The plan involved characterization of the water-bearing zone in terms of depth, type of deposit and direction of flow, relative to the drinking water source. This was undertaken through the use of test pits, boreholes and piezometers. Potential construction impacts were identified. In this case, the natural gas pipeline was to be installed by a directional drill that injects bentonite (drilling mud) to provide lubrication and to keep the drill hole from collapsing. Mitigation measures related to containment of bentonite and fuel handling in the vicinity of the artesian well were prescribed. The rationale for directional drilling this section of the pipeline was to prevent erosion of the steep slopes and to undercross a watercourse. The water-bearing deposit consisted of a sandy-gravel layer that was found to occur at a depth of 3.65 meters. Every effort was made to maintain the drill hole for the pipeline above this depth. In addition to sampling the artesian well for chemical and bacterial parameters in advance of construction and upon completion of work in the vicinity, water from the artesian well and one of the piezometers was checked for turbidity every two hours. Other contingency plans included digging “burp-holes” to reduce the potential for bentonite frac-outs and having a water supply truck on stand-by should turbidity levels reach unacceptable levels. Construction proceeded smoothly. Minor frac-outs occurred and were appropriately contained. The turbidity readings and water quality samples taken before, during and post-construction confirmed that there were no negative impacts on the artesian well. The methods used on this project are directly applicable to other pipelines that may be constructed in the vicinity of artesian wells.
Hydraulic Transient of a Liquid Fuel Unloading System
Authors: Zheng Yifan
Published: March 2009

This paper describes the efforts involved in successfully designing a large scale offshore liquid fuel unloading system. The hydraulic transient analyses conducted during various design stages produced acceptable transient pressures under various transient events including pump trip, normal and emergency shutdowns (ESDs), confirmed that the maximum marine tanker design rail pressures were within limits, and determined that the transient pulse loading on various above-ground pipe segments can be substantially reduced by providing effective surge relief devices. The paper also describes experience gained in designing and maintaining the air vessels to ensure their availability in protecting the system piping.
Utilization of Vertiline Wire Conveyed Smart Tools in Gas Storage Field Pipeline Applications
Authors: Buck Brian S. , Philo James D.
Published: March 2009

Consumers Energy, which is the largest natural gas utility in the state of Michigan and fifth largest in the United States, operates thirteen natural gas storage fields in the state as part of its Gas Transmission and Storage system. These storage fields consist of a network of storage wells connected via a series of short pipeline laterals and headers. Typical field configuration consists of one or two main headers with several laterals branching off to the gas storage wells. Due to the shorter line lengths (2.5 miles or less) and other operational conflicts, it is difficult to utilize conventional online smart pigging methods to assess the integrity of these laterals and headers. Based on the type (welded steel), average age, and operating conditions of the pipelines in these storage fields, an internal inspection method was desired. Consumers Energy has teamed with Baker Atlas to utilize their Vertiline wire conveyed MFL (magnetic flux leakage) smart tools to assess the integrity of these gas storage field headers and laterals. The Vertiline technology was originally conceived for down hole well casing integrity analysis, however, the application was found to be ideal for short section, limited access, and otherwise unpiggable pipelines. The Baker Vertiline technology can currently be used on pipeline sizes up to 24” in diameter, and larger diameter tools are under development. This paper will explore the process that Consumers Energy undertook to utilize wire conveyed MFL smart tools in its gas storage field pipelines. Field preparation for tool runs, running the tool and gathering data, and data presentation will all be reviewed. The advantages and disadvantages, techniques, capabilities, and technology of the wire conveyed MFL smart tools themselves will also be discussed, along with other potential applications such as use in analysis of pipeline river crossings, pipelines lacking pig launching facilities, and offshore production lines.
Circumferential SCC in Pipeline Due to Land Creeping
Authors: Pope Alexandre M. , Camerini Cla´udio S. , Teixeira Jose´ C. G. , Piza Marcelo T. , Baptista Walmar , de Souza Byron G. , Oliver Joa˜o H. L.
Published: March 2009

This paper describes the analyses performed in a circumferential rupture that occurred in a pipeline crossing a high slope region in the Southern part of Brazil. The pipeline was made of API 5L-X46 steel, coal tar coated, and has been in operation since 1977. The failure occurred after a period of heavy rains and was clearly associated to land creeping. The fracture occurred in parent metal 2770 mm away from the nearest circumferential welding. This fracture initiated in an approximately 3×70 mm external surface crack. Besides, several secondary parallel cracks were detected at a 6 o’clock position.
Influence of Humic Substances on the Corrosion of the API 5LX65 Steel
Authors: Rodrigues Luciana Machado , Pinheiro Dick Lui´s Frederico
Published: March 2009

Aiming to simulate the underground corrosion of pipeline steels in tropic soils, the electrochemical behavior and corrosion morphology of API 5LX65 steel were studied in 0.01molL−1 Na2SO4 solutions with additions of humic (HA) or fulvic (FA) acids extracted from a peat soil. These humic substances have a higher carboxylic and nitrogenated character for HA, and a higher concentration of oxidized groups for FA, as determined by infrared (FTIR) and Raman spectroscopies. The corrosion tests showed that HA and FA enhance the pitting corrosion of the API 5LX65 steel. The observed pits are always associated to the presence of the rounded calcium aluminate inclusions of API 5LX65. Raman spectra of the corrosion products partially covering pits and inclusions suggest the formation of organic Fe compounds. The influence of humic substances on pit nucleation was attributed to passivity breakdown on the interface between Fe and inclusions, by the formation of partially soluble compounds of Fe and humic substances.
Pipeline Dent Management Program
Authors: Ironside Scott D. , Carroll L. Blair
Published: March 2009

Enbridge Pipelines Inc. operates the world’s longest and most complex liquids pipeline network. As part of Enbridge’s Integrity Management Program In-Line Inspections have been and will continue to be conducted on more than 15,000 km of pipeline. The Inspection Programs have included using the most technologically advanced geometry tools in the world to detect geometrical discontinuities such as ovality, dents, and buckles. During the past number of years, Enbridge Pipelines Inc. has been involved in developing a method of evaluating the suitability of dents in pipelines for continued service. The majority of the work involved the development of a method of modeling the stresses within a dent using Finite Element Analysis (FEA). The development and validation of this model was completed by Fleet Technology Limited (FTL) through several projects sponsored by Enbridge, which included field trials and comparisons to previously published data. This model combined with proven fracture mechanics theory provides a method of determining a predicted life of a dent based on either the past or future operating conditions of the pipeline. CSA Standard Z662 – Oil and Gas Pipeline Systems provides criteria for the acceptability of dents for continued service. There have been occurrences, however, where dents that meet the CSA acceptability criteria have experienced failure. The dent model is being used to help define shape characteristics in addition to dent depth, the only shape factor considered by CSA, which contribute to dent failure. The dent model has also been utilized to validate the accuracy of current In-Line Inspection techniques. Typically a dent will lose some of its shape as the overburden is lifted from the pipeline and after the indentor is removed. Often there can be a dramatic “re-rounding” that will occur. The work included comparing the re-rounded dent shapes from a Finite Element model simulating the removal of the constraint on the pipe to the measured dent profile from a mold of the dent taken in the field after it has been excavated. This provided a measure of the accuracy of the tool. This paper will provide an overview of Enbridge’s dent management program, a description of the dent selection process for the excavation program, and a detailed review of the ILI validation work.
High-Speed Tandem GMAW for Pipeline Welding
Authors: Blackman Stephen A. , Dorling David V. , Howard Roger
Published: March 2009

Tandem gas metal arc welding (GMAW) differs from conventional GMAW as two welding wires are passed through the same welding torch. A single torch with two contact tips is used to feed both wires into a single weld pool. Although the potential of the multi-wire GMAW process was first explored as early as the 1950’s, it has not become commercially viable until relatively recently due to performance limitations associated with the power source technology, that resulted in process instabilities. However, with the advent of modern microprocessor-controlled inverter power sources and an improved understanding of metal transfer characteristics, tandem GMAW is now being successfully applied in many industries. Over the last four years, Cranfield University’s Welding Engineering Research Centre and TransCanada Pipelines have developed tandem GMAW for pipeline welding. Cranfield have developed a tandem GMAW torch specifically for use with narrow gap weld preparations utilized in pipeline welding. The process has been proven capable of high deposition rates and welding speeds two to three times those of conventional mechanized pipeline welding. Based upon this earlier work, the Cranfield Automated Pipewelding System (CAPS) is now being developed. This uses two tandem torches on a single carriage (dual tandem welding). The high speed of tandem GMAW is retained and two passes are deposited simultaneously which further reduces welding times. This results in a significant reduction in the number of welding stations required to achieve a given number of weld’s per day and leads to major savings in labor and equipment costs. In comparing welding systems for a recent project estimate, CAPS resulted in a 26% saving in alignment, welding, NDT and coating costs when compared with conventional mechanized welding systems. A major benefit of CAPS is that it has evolved from existing technology. It is not a ‘one-shot’ process. The completed weld has a very similar profile to conventional mechanized pipeline welds so conventional radiography and automated ultrasonic testing can be used for weld inspection. The weld metal microstructure and metallurgical properties are also similar to conventional mechanized pipeline welds. CAPS is therefore suitable for use on all linepipe materials including X80 and X100 steels. This paper reviews the development of the process and equipment together with information on productivity and metallurgical properties.
Real Time Statistical Leak Detection on the RRP Crude Oil Network, Holland
Authors: Hoeijmakers Joep , Lewis John
Published: March 2009

Prior to the year 2000, the RRP crude oil pipeline network in Holland and Germany was monitored using a dynamic leak detection system based on a dynamic model. The system produced some false alarms during normal operation; prompting RRP to investigate what advances had been made in the leak detection field before committing to upgrade the existing system for Y2K compliance. RRP studied the available leak detection systems and decided to install a statistics-based system. This paper examines the field application of the statistics based leak detection system on the three crude oil pipelines operated by RRP. They are the 177 km Dutch line, the 103 km South line, and the 86 km North line. The results of actual field leak trials are reported. Leak detection systems should maintain high sensitivity with the minimum of false alarms over the long term; thus this paper also outlines the performance of the statistical leak detection system over the last year from the User’s perspective. The leak detection experiences documented on this crude oil pipeline network demonstrate that it is possible to have a reliable real-time leak detection system with minimal maintenance costs and without the costs and inconvenience of false alarms.
Recent Quality Achievements on Steel Plate for Line Pipe
Authors: Bauer Ju¨rgen , Schwinn Volker , Tacke Karl-Hermann
Published: March 2009

From the viewpoint of a plate manufacturer the status of steel plate quality for line pipe applications is discussed. Technologies of the steel shop and the plate mill to create high class material are presented, as well as alloying and accelerated/intermediate cooling concepts. The levels of consistency that can be reached are illustrated on recent contracts. This includes sour gas resistant line pipe steels, applications for low temperatures and the extension of these features towards high strength grades.
Leak Detection Program in Petrobras Transportation Company
Authors: Tolmasquim Sueli Tiomno , de Tarso A. Correia Paulo , Robertson Douglas
Published: March 2009

The objective of this paper is to describe the process used by TRANSPETRO to select and implement a leak detection system. The process consists of three steps: selection of a leak detection system, evaluation on a trial basis, and project implementation, which includes the negotiation of the contract and project implementation strategies. PETROBRAS Transportation Company — TRANSPETRO — operates several networks of pipelines in Brazil, with a total length of 6,500 km transporting petroleum products and crude, and 3,500 km transporting natural gas. Over the last two years, two large leaks occurred in the pipelines operated by TRANSPETRO. After analyzing these incidents, TRANSPETRO came to the conclusion that the consequences of leaks could be minimized with a reliable leak detection system and a proper emergency response procedure. To ensure that the leak detection system was fit to purpose and represented the best fit of technology to requirements, TRANSPETRO used a plan that involved three steps. First, based on the leak detection system criteria, TRANSPETRO and PETROBRAS R&D Center engineers selected a software based leak detection system with a hydraulic model (CPM, according to the API 1155 [1]) from among various leak detection techniques and products commercially available in the international market. Second, the selected leak detection system was implemented on two pipeline segments on a trial basis to evaluate it against TRANPETRO’s selection criteria for oil pipelines under real world conditions. Finally, after the successful completion of the trial, the implementation project, including up to 150 pipeline segments, was contracted.
Managing Pipeline Health, Safety and Environmental Risks
Authors: Agoncillo Louie A.
Published: March 2009

The terms “risk assessment” and “risk management” are both commonly used to describe some method of identifying, understanding and controlling risks. In the pipeline industry, risks are encountered and must be addressed at the concept and design phase, construction and commissioning phases and the operations and maintenance phases. Risk assessment is a detailed, systematic examination of any pipeline activity, location or operation system to identify risks, understand the probability and potential consequences of the risks, and to review the current or planned approaches to controlling risks. Risk management is the set of ongoing management and engineering activities to ensure that risks are assessed and controlled to a reasonably achievable, tolerable level. A continuous improvement approach is also required. A wide variety of risk management or loss control activities are in use in the pipeline industry internationally. The purpose of this presentation is to discuss some of these techniques and the benefits to be derived from the application of risk management techniques throughout all phases of pipeline activity. Effective risk management allows organizations to preempt losses and get on top of managed system problems before incidents and accidents occur. After all, the vast majority of the Health, Safety and Environment (HSE) problems at work sites are system problems, not operator problems. This paper will present an overview of several risk assessment and risk management techniques to acquaint conference participants with the information needed to select the most appropriate techniques to utilize during the various phases of pipeline development and operation.
The Application of Near-Surface Geophysics at Proposed Pipeline River Crossings: A Comparative Overview of Various Techniques and Their Associated Capabilities and Limitations
Authors: Tarrant Paul , Baines David
Published: March 2009

The cost, design, and in some instances, feasibility of directional drilling large diameter or lengthy pipeline river crossings is primarily dependent on ground conditions encountered during construction. Geotechnical investigations are commonly used to explore and assess subsurface conditions at proposed crossings. Ground conditions are determined using borehole drilling and near surface geophysics. Borehole drilling provides subsurface sediment stratigraphy and depth to bedrock information. Geophysics is used to provide information between borehole locations or where borehole drilling is determined to be too difficult or too costly. When used to augment borehole results, geophysical surveys provide more complete geologic cross-section models throughout the length of a proposed directional drill path. This paper presents an overview of the more common geophysical methodologies used to profile subsurface conditions at proposed pipeline crossings. The methods discussed include ground penetrating radar (GPR), seismic refraction profiling and electrical resistivity tomography (ERT). The appropriateness and feasibility of each method is discussed in terms relating to investigation objectives of geotechnical and pipeline design engineers. All three methods were applied to two survey lines at a typical river crossing site on the Bow River, downstream from Calgary, Alberta. Results from the overlapping surveys are presented and the capabilities and limitations for each method compared. Borehole information obtained within the survey area is used to corroborate the interpreted geophysical results.
Environmental Loadings and Geotechnical Considerations for the Northstar Offshore Pipelines
Authors: Paulin Michael J. , Nixon Derick , Lanan Glenn A.
Published: March 2009

BP Exploration (Alaska) Inc. completed the installation of the first subsea Arctic oil production pipeline in April 2000 for the Northstar Development Project. The drilling and production facilities are located at Seal Island, approximately 10 km offshore of the Alaskan Beaufort Sea coast. Twin 273.1 mm (10-inch) oil and gas pipeline systems run approximately 10 km from Seal Island, through a lagoon area, to a shore crossing, and then overland for approximately 18 km. The unique aspects of this design included the pipeline environmental loadings, geotechnical considerations, and the use of limit state design procedures for extreme loading conditions. Environmental loadings and geotechnical conditions (in-situ and backfill) along the pipeline route were a major factor in the design of the offshore portion of the pipelines. Data collection of environmental conditions (e.g. ice gouging and strudel scour) and proper evaluation of the same were required to provide appropriate design data. Comprehensive field and laboratory programs were undertaken to generate the necessary geotechnical data for design. The evaluation of and design for unique Arctic environmental loading conditions including ice gouging, offshore permafrost, upheaval buckling, and strudel scour are described. Trenching and backfilling aspects of the pipeline design are also discussed. The paper closes with a general overview of the pipeline operations since the start of oil production in November 2001.
Stress Analysis of Pipelines With Composite Repairs
Authors: Meniconi Luiz C. M. , Freire Jose´ L. F. , Vieira Ronaldo D. , Diniz Jorge L. C.
Published: March 2009

The repair of corroded pipelines with fiber reinforced composite materials is a well-developed practice in the oil and gas transportation industry. Laboratory hydrostatic burst tests and field practice of several years have shown that these repairs are effective for pipelines with external corrosion defects. This paper deals with laboratory tests carried out to compare the behavior of fiber reinforced composite repairs applied to defects machined in pipeline test specimens. The experimental results were compared to results from Finite Element Analysis (FEA) of the tubes tested. The parameters of FEA were calibrated to this specific problem, beforehand. Some hipotheses were tested during FEA trials to better explain the experimental results. The results indicated that, up to the starting of yielding of the pipe defected region, practically only the elastic pipe stresses equilibrate the pressure loading, due to the steel high Young modulus. After yielding, the composite material starts to work, carrying an important part of the pressure loading increments. Experimental results also showed that the repair systems tested allowed the pipes to achieve the original design pressure before bursting. However, only one of the repair systems was approved in all strength verification tests for both internal and external defects. This system operated for four hours under a hydrostatic pressure test associated to the specified minimum yield strength (SMYS) of the steel and was also able to support ten pressure cycles of the design pressure afterwards, without showing any visual damage.
Autonomous Pipe Searching Robots
Authors: Renzi Adam D. , Walter Wayne W.
Published: March 2009

A pair of autonomous microcontroller-based robots were designed, built, and tested to inspect the inside of an 8 in pipe. The pair consists of a “scout” which travels along the inside of the pipe and scans the surface for holes using an array of touch sensors. Once a hole is found, the “scout” communicates the position of the hole to a second “mule” robot that has an on-board sealant dispensing system. After the scout moves out of the way, the mule moves to the hole location and dispenses sealant to seal the hole. Both robots are controlled by a BASIC Stamp microcontroller and propelled by servomotor driven wheels in response to sensor input. Communication is accomplished using wireless RF transceiver boards. This paper discusses the design, build, and test of these cooperative robots; the problems encountered, and how these problems were solved in order to successfully meet the project requirements of creating a two robot system that could find and simulate the sealing of holes in pipes.
Pipeline Route Assessment at River Crossings and in Steep Terrain: Geophysical, Hydrologic and Geotechnical Characterization
Authors: Steensma Gilein J. , Kappelhoff Mark A. , McInnis Duncan A. , Gilson Eric
Published: March 2009

Pipeline river crossings and sections of pipeline routes where steep terrain requires directionally drilled borings have the highest chance of being successfully designed and constructed if subsurface geological conditions are understood. In this paper we present results of geophysical surveys conducted to characterize the subsurface at two pipeline river crossings and at a site where steep topography would likely require directional boring below the face of a steep hillside. The objective is to help assess and minimize the risk in engineering design in difficult terrain by analyzing subsurface geology from geophysical data and vertical geotechnical borings, and evaluating the dynamic behavior of the river itself through hydrologic analysis. Risk factors can be assigned on the basis of lithology and environmental considerations relating to the level of potential impact in different parts of the crossing. The laterally heterogeneous nature of river channels, consisting of stacked paleochannels and floodplains could require a significant number of vertical geotechnical borings for adequate characterization of the entire crossing. We find that a combination of electrical resistivity tomography (ERT), seismic refraction tomography (SRT) and ground penetrating radar (GPR) data can efficiently provide us with an understanding of electrical and mechanical properties from which lateral variations and depth extent of lithology along the proposed boring can be inferred. Confirmatory vertical geotechnical borings allow us to verify our interpretation at two locations. Geophysical data are used to laterally extrapolate the lithologic interpretation and define, in conjunction with surface water hydrologic considerations, the minimum depth of directionally drilled borings and optimum locations of ingress/egress points. The investment in a geological assessment study to understand subsurface conditions prior to beginning horizontal boring operations is essential to mitigate risk and ultimately may save money. In the case of steep terrain, geophysical data can provide valuable information on the vertical and lateral variations in subsurface properties in areas where it would be impossible to safely drill vertical borings. Our last case history is an example of the geological information that can be efficiently inferred from geophysical surveys conducted in steep terrain.