bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatigue of Aluminum-Alumina-Chrome Carbide Composite Coating
Authors: Kireitseu Maksim , Yerakhavets L. , Nemerenco Ion
Published: March 2009

In this paper fatigue and fracture of the Al-Al2O3-CrC, coatings have been investigated by in situ experiments performed in a scanning electron microscope. More importantly, micromechanical models using arrays of internal or surface cracks have been developed. The models provide mechanics of deformation and failure for the coating. The models also reveal the role of overloading in crack arrest, which may well be exploited in the safe design of toughened ceramics against fatigue. Initial overloads prior to cyclic loading are found to reduce significantly the crack driving force in post-overload fatigue crack growth. It expected that pre-service overloading has a great potential for improving the fatigue properties of composite coatings based on oxide ceramics and chrome carbide.
Fuel Consumption Index for Proper Monitoring of Power Plants: Revisited
Authors: Lang Fred D.
Published: March 2009

This paper presents an method for heat rate monitoring of power plants which employs a true “systems approach”. As an ultimate monitoring parameter, derived from Second Law concepts, it quantifies system losses in terms of fuel consumption by individual components and processes. If electricity is to be produced with the least un-productive fuel consumption, then thermodynamic losses must be understood and minimized. Such understanding cuts across vendor curves, plant design, fuels, Controllable Parameters, etc. This paper demonstrates that thermal losses in a nuclear unit and a trash burner are comparable at a prime facia level. The Second Law offers the only foundation for the study of such losses, and affords the bases for a true and ultimate indicator of system performance. From such foundations, a Fuel Consumption Index (FCI) was developed to indicate specifically what components or processes are thermodynamically responsible for fuel consumption. FCIs tell the performance engineer why fuel is being consumed, quantifying that a portion of fuel which must be consumed to overcome frictional dissipation in the turbine cycle (FCITCycle), the combustion process (FCIComb), and so forth; and, indeed, how much fuel is required for the direct generation of electricity (FCIPower). FCIs have been particularly applicable for monitoring power plants using the Input/Loss Method. FCIs, Δheat rates based on FCIs, and an “applicability indicator” for justifying the use of Reference Bogey Data are all defined. This paper also presents the concept of “dynamic heat rate”, based on FCIs, as a parameter by which the power plant operator can gain immediate feedback as to which direction his actions are thermally headed: towards a lower or higher heat rate.
Case History: Automation of an Existing Cogeneration Facility — Metamorphosis of an Existing Central Utility Plant Facility
Authors: Haaland Ole E. , Conway Michael
Published: March 2009

The scope was straight forward; design and install a complete SCADA system to automate as much as reasonably possible the utility plant consisting of: • One gas turbine cogeneration unit with duct firing, • Three reciprocating engine generators, • Two utility sources, • Three Absorption chillers, • Four electric chillers, • Two duel fuel boilers, and • 2 cooling towers. Prior to this project, the entire utility plant was operated manually. This included everything from chiller loading to Power Factor control.
Power Plant Life/Risk Assessment Techniques
Authors: Clark M. A. , Browne R. , Flaman M. , LeHockey E. M. , Thompson I.
Published: March 2009

Many fossil power plants in N. America are now required to operate in excess of 20 years beyond their original design life. To ensure safe reliable operation, life assessment of key high-risk components is required. Life assessment of older power plant requires the application of many diverse techniques and the integration of several engineering disciplines with plant operations experience. Traditional approaches to life assessment of high temperature components will be described and illustrated with examples taken from experience on large coal fired plants from the old Ontario Hydro system. These results will include a number of high energy piping welds with approximately 160,000 hours of service that contain intercritical region heat affected zone (HAZ) creep damage (Type IV). These welds have been monitored through in-situ metallography techniques for over 20,000 hours since damage was first detected. New techniques are also being developed or employed: miniature sample testing for evaluating creep and fracture properties along with miniature EDM sample removal techniques. The use of innovative mechanical scratch gauges for the purpose on-line strain monitoring of mechanical or civil structures. The use of orientation imaging microscopy (OIM) for simultaneous comprehensive characterization of the interaction between residual plastic strains, texture, grains size distribution and other crystallographic features as applied to root cause failure analysis. Finally risk based asset management software RBMS for the purpose of detailed component assessments. Examples/results of these techniques will also be presented in the paper.
Exergy Analysis of Carryover Leakage Irreversibilities of a Power Plant Regenerative Air Heater
Authors: Jassim Rahim K. , Habeebullah Badr A. , Habeebullah Abdulraof S.
Published: March 2009

Energy recovery devices can have substantial impact on process efficiency and their relevance to the problem of conservation of energy resources is generally recognised to be beyond dispute. One type of such a device, which is commonly used in fossil fired and air conditioning systems, is the rotary regenerator in which a stream of hot waste gas exchanges heat with fresh atmospheric air through the intermediate agency of a rotating matrix. As there are gas streams involved in the heat transfer and mixing processes, then there are irreversibilities, or exergy destruction, due to chemical reaction, pressure losses I˙ΔP and due to temperature gradients I˙ΔT . These principle components of total process irreversibility are not independent and there is a trade-off between them. Therefore the purpose of this research paper is to demonstrate the importance of the use of exergy analysis in the minimisation of carryover leakage irreversibilities of a symmetric balanced rotary regenerator. The chemical exergy E˙o and physical exergy E˙ph are calculated and the ratio of chemical and physical irreversibilities has been evaluated for a rotary regenerator used for air preheating in a coal-fired power plant. A numerical finite difference technique has been used to calculate the fluid and matrix temperature distributions effect on the regenerator performance. The effects of variation of the principal design parameters on the irreversibilities and on the regenerator effectiveness are examined and recommendations are made for the selection of the most appropriate parameters.
Experimental Study on a Packed Bed Humidifier in an Evaporative Gas Turbine
Authors: Dalili Farnosh , Westermark Mats
Published: March 2009

This paper examines the performance of gas turbine cycles operating with a mixture of air and water vapor. Special attention is paid to the humidification tower, where the water vapor is added to the air. The experiments in this study have been carried out in the first evaporative gas turbine pilot plant located at Lund Institute of Technology in the southern part of Sweden. This pilot plant is based on a Volvo VT600 gas turbine with a design load of 600 kW. The compressor pressure is just above 8 bars and the intake air-flow is 3.4 kg/s. Roughly 70 percent of the compressed air is humidified in the humidification tower, which is the only humidifying device. The tower diameter is 0.7 m and the total flexible packing height is 0.9 m of a stainless steel structured packing with a specific surface area of 240 m2/m3. The number of mass transfer units in the humidifier was experimentally determined to about 3 for a packing height of 0.45 m. The height of a transfer unit from the literature data for the packing is predicted to be 0.24 m. With a packing height of 0.45 m, only about 2 transfer units are expected from the packing. However, the droplet zones above and below the packing contribute about 1 transfer unit. Thus, it is concluded that the mass transfer performance of the packing is adequately predicted by literature data. Equations are provided to adjust the height of a transfer unit for other pressures and temperatures. For full-scale plants operating at higher pressures and temperatures it is suggested that the high quality exhaust heat, (temperatures above the boiling point) is recovered in a boiler and injected as steam. The remaining part of the exhaust heat, (temperatures below the boiling point) is used to produce hot water for a relatively small humidification tower using only a portion of the compressed air flow.
Advanced CFD Post-Processing for Pulverized Fuel Flame Structure and Emissions
Authors: Niksa Stephen , Liu Gui-Su , Felix Larry G. , Vann Bush P.
Published: March 2009

The simulation strategy described in this paper provides an alternative to conventional CFD post-processing to estimate exhaust NOX emissions. The method first analyzes a CFD furnace simulation to specify temperature histories and mixing rates. Then the bulk flow patterns are represented with an equivalent network of idealized reactor elements. Detailed reaction mechanisms are then applied over the reactor network, including the most fully validated reaction mechanisms for coal devolatilization and char oxidation and complete elementary reaction mechanisms for chemistry in the gas phase and in soot. The analysis predicted the NOX emissions from 1.7 MWt pilotscale flames of coal and coal/biomass blends within experimental uncertainty over a broad range of O2 concentrations, with and without staging. The predicted unburned carbon emissions were qualitatively correct, but char reactivity parameters would need to be specified in a one-point calibration for quantitative predictions. The analysis also characterized distinctive chemistry within the flame core, a mixing layer for secondary air entrainment, an overfire air zone, and a char burnout zone. The main practical benefit of the mechanistic complexity is that simulations based on detailed mechanisms require fewer parameter adjustments than CFD simulations whenever different fuels are considered.
Evaluation of Pump Performance in Complex Systems by Dynamic Modeling
Authors: Biba Paul
Published: March 2009

The evaluation of pump performance in complex hydraulic networks is often difficult due to the complexity of the system operation. While inservice testing is often performed when the particular system is in a test mode, the test conditions may be different from the actual operating conditions under which the system would be required to operate. In addition, the pump may have to function under various postulated accident scenarios, which can not be duplicated during plant normal operation. This paper will present a method of upgrading pumps by using a dynamic model, which allows the evaluation of the many factors affecting the system performance, in order to assure system operability.
Combating of the Solid Particle Erosion in a Steam Turbines
Authors: Mazur Z. , Urquiza G. , Campos R.
Published: March 2009

The causes and possible solutions of solid particles erosion of the steam path components to reducing it substantially are presented. Applying numerical CFD simulations excessive solid particle erosion damage of the blades tenons, wheel filets, rotor labyrinth seals and main stop valves were studied and steam/solid particles flow conditions which play a main role in the erosion process determined. Afterwards, the flow was simulated introducing specific changes to the geometry of components in order to modify the flow pattern favourably. In each case analyzed, the results confirmed that is possible to reduce the erosion process significantly due to reduction of the volumetric flow rate and velocity of vapour (case of blade tenons), velocity reduction and to modify the angle of particle flow incidence on the surface by increasing the distance from the labyrinth seal to the rotor wheel (case of wheel filets) and flow velocity reduction due to incorporating a steam flow deflector to the diaphragm, which changing flow direction in the inlet zone to the rotor labyrinth seal channel (case of rotor labyrinth seal). In the case of the main steam valve, introducing profile off-set on the valve spherical surface, the steam/particle flow was separated from the valve critical zone, changing the particles trajectories and angle of impact on the surface, resulting in erosion rate reduction. Also, a passive methods of combating solid particle erosion of tenons in the form of weld deposits around them as a protective barrier and wheel filets, rotor labyrinth seals and blades and shrouds coating are presented. All analyzed design modifications and other improvements were implemented and its performance monitored.
Investigation of Intermediate Products in Post-Catalytic Combustion Using an Ion Probe
Authors: Mogi Toshio , Arai Masataka
Published: March 2009

The combustion phenomena of vaporizing spray in a catalyst and a post-catalyst flame were studied experimentally. This study is a part of the development of a catalytic combustor for a ceramic gas turbine engine. A palladium catalyst supported on the cordierite honeycomb monolith was used as a combustion catalyst. A premixture of air and kerosene vapor was introduced into the catalyst. The parabolic shaped flame, called a thermal combustion flame, which was supported on the catalyst, was formed even when the equivalence ratio of the mixture was less than stoichiometry. Intermediate products in the exhaust gas after the catalyst honeycomb were investigated using an ion probe. When the thermal flame appeared, ions were detected in the exhaust gas between the honeycomb and the flame. It was indicated that some reactive species were included in the exhaust gas. Even when the thermal flame did not appear, the ions were slightly detected in the exhaust gas. The concentration of the ions rapidly decreased a slight distance away from the honeycomb surface and increased in front of the thermal flame. When the equivalence ratio was increased, the ion concentration at the honeycomb surface increased. Furthermore, in order to investigate the effect of the mixing behavior of the vaporized fuel on post-catalytic combustion, the length of the mixing tube was changed. When the mixing of fuel was insufficient, the thermal flame appeared at a lower equivalence ratio than the more homogeneous mixing condition. However, regardless of the mixing length and equivalence ratios, the concentration of ions near the honeycomb surface was almost constantly at the onset conditions of the thermal combustion flames.
Application of the Manometric Engine to Increase Power Plant Efficiency
Authors: Belcher Alan E.
Published: March 2009

Approximately 50% of the total heat input to steam-driven Rankine cycle thermoelectric power plants is rejected through the condenser. Cogeneration increases plant efficiency by applying part of the total input heat directly to some end process. However, this can be a severe limitation to those power producers interested only in generating electric power. This paper describes the application of the manometric engine to directly convert a significant portion of this waste heat to either electric power or compressed air. High plant efficiencies are thus achieved, with a concomitant reduction of emissions and increase of profitability, without the need for an off-site process to utilize the waste heat.
Optimizing Selection of Appropriate Power Generation Systems in Indonesia by Using Distance Based Approach Method
Authors: Widiyanto Anugerah , Kato Seizo , Maruyama Naoki
Published: March 2009

A deterministic quantitative model has been developed for use to compare the technical, economical and environment feature of various electric power generating plants. The model, which is based on matrix operations, is used in evaluating the various aspects of energy sources available for the electricity generation systems in a developing country. Several energy sources are chosen which could be considered for production of electricity to meet current and future electricity demands. A complete set of energy sources will include fossil fuel fired power plants, nuclear power plants, and natural-renewable energy power plants. A customized computer code is developed to evaluate the overall function for each system from the performance corresponding to the selected energy attributes includes five area of concerns; energy economy, energy security, environmental protection, socio-economic development and technological aspects for the electric power generations. The model developed in this study is applied to the Indonesian’s electric power sector development. Most of the data required for the model application are obtained from various sources related to power industry in Indonesia, such as the Electricity Generating Authority of Indonesia (Perusahaan Listrik Negara, PLN), Government of Indonesia, World Bank, Asian Development Bank, United Nations, and other sources, both in published and public domains. The optimization technique is kept flexible so that it can accommodate other attributes that will be found to be important according to the decision maker’s preference. By so doing, the model virtually can be used to attack any decision problem with various different attributes to reach an optimal decision concerning the selection of energy sources for electricity generation. The result of this study will be a rank of energy sources for Indonesia power generation systems based on the composite distance of each alternative to the designated optimal source of energy.
Initial Operating Experiences and Overall Enhancements at the Chilean Coke Fired Petropower Cogeneration Facility
Authors: Studley Bruce C. , Fuentes Victor
Published: March 2009

On November 1, 1998 the Petropower Energia Limitada Project, located adjacent to Petrox’s 84,000 barrel per day (bpd) refinery in Talcahuano, Chile, entered into Commercial Operations. In addition to being the first public/private industrial partnership in Chile, it also was the first to combine petroleum coking technology with cogeneration technology in a single project financing. The project consists of a Delayed Coker Facility, which includes a 12,000 bpd Delayed Coker Unit and a 7,000 bpd Hydrotreating Unit, and a 74 MW (nominal, gross) Cogeneration Facility. The coke produced fuels a Foster Wheeler Circulating Fluidized Bed Boiler (CFB), and the energy produced provides electric power for the Petrox Refinery, the Delayed Coker Facility, and third parties, and high pressure steam for the refinery. The Cogeneration Facility, which consumes 24.8 Tonnes Per Hour of green coke, produces high-pressure steam, demineralized water and electricity for export to the refinery. The cogeneration unit also exports electricity, boiler feedwater and plant air to the Delayed Coker Facility. This leaves approximately 42 MW which is being exported to local third parties and the national grid. Environmentally, the overall project has resulted in a decrease in sulfur dioxide and particulate emissions from the refinery because of emission controls in the CFB, and elimination of burning fuel oil in the old utility system. Overall, the Delayed Coker Facility has permitted Petrox to refine heavier, less costly crudes, and the Hydrotreater Unit produces cleaner gasoline and diesel products. Petrox obtained these benefits without the expenditure of capital on the project, other than a small equity investment. The Cogeneration Facility has, and will continue to provide a long term, environmentally friendly solution to disposal of the high sulfur content coke produced by the coker, and maximizes its value as a high BTU (kilojoule - kJ) fuel for the Cogeneration Facility. The Cogeneration Facility has supplied all the refinery’s utility needs reliably and consistent with its expansion plans. After briefly describing the overall project, this paper places emphasis on the cogeneration plant with a focus on the operational experiences, including fouling, and the reliability improvements undertaken during the plant’s last three years of commercial operation. In addition, O&M costs and an overview of project economics are discussed.
San Onofre Nuclear Generating Station: Unit 3 Turbine Generator Repair Following the Loss of Lubrication Oil Incident
Authors: Leech Stuart , Chetwynd Russell , Simma Fred
Published: March 2009

Upon return to service from a refueling outage, the 1150 MW SONGS Unit 3 was at 39% reactor power when a circuit breaker fault resulted in a fire, a partial loss of AC off-site power, and a reactor shutdown. The failure of a circuit breaker to function properly resulted in the unavailability of the DC driven turbine emergency lubricating oil pump, causing extensive damage to the turbine generator. The power supply crisis in California at this time highlighted the need for an urgent understanding of the seriousness of the damage to the turbine generator, the consequences for the repair and timely return of the unit to service. Initial inspections indicated that all rotor line bearings had suffered from loss of white metal and most of the housings were distorted. Rotor journals were scored from solid contact and subject to excessive heat damage. Rotor steam seals had suffered rubbing damage. In view of the component sizes associated with such a large machine, and the need to minimize the outage duration, a large proportion of the repair work was undertaken on site. This enabled SCE to project manage the work themselves ‘in-house’. It was decided that the HP and the three LP turbine rotors would remain on site, with only the Generator rotor and the complete Exciter being shipped to the OEM’s workshops for repair. Specialist sub-contractors were employed for site machining and heat treatment. Consultants were hired for specialist technical matters, primarily related to metallurgical issues, to complement the in-house expertise of both SCE and ALSTOM. The serious nature of the damage required close cooperation between SCE and ALSTOM the OEM. It was important to understand the design margins and therefore the scope for repair, and long term integrity of the solutions. The detailed repair instructions were prepared and controlled jointly between ALSTOM and SCE engineers on site, with extensive technical back-up provided from the OEM engineering design departments. Similar close co-operation on the re-design of components and fast track supply of spare parts was crucial to the success of the project.
Thermographic Quality Assurance of Turbine Engine Components
Authors: Chaudhry Bharat B. , Holmes Hank , Shepard Steven M. , Ahmed Tasdiq
Published: March 2009

Although highly desirable from a cost and reliability standpoint, 100% inspection of Ni-super alloy components in the early stages of the manufacturing process has generally been regarded as overly time consuming, and ineffective at identifying subsurface irregularities in the internal structure. As a result, quality assurance is often limited in scope. To rectify the situation, we have implemented a 100% inspection system for quality assurance at Stolper Fabralloy using an active thermography system (EchoTherm, Thermal Wave Imaging, Inc.). Prior to installation, a series of tests were performed to insure that the system could meet customer requirements and match the resolution of the ultrasonic C-scan that had previously been used for QA of flat panels. As a result of these tests a calibration procedure was developed. The system is currently used to inspect flat and formed transition panels and other components using various thermal excitation methods. Operators have been trained per ASNT TC-1A Level I and II. Using the thermographic system, we have successfully identified defects including inter-layer disbonds and cooling channel blockage. The system software allows us to simultaneously view and analyze the results for an entire transition. Total inspection time has been reduced by an order of magnitude, to 30 minutes for a 2’ × 3’ transition.
Development of the RSFC Low NOx Burner: From Fundamentals to Industrial Applications
Authors: Bee´r J. M. , Toqan M. A. , Haynes J. M. , Borio R. W.
Published: March 2009

Research and development of the low NOx Radially Stratified Flame Core (RSFC) burner is followed from its fundamental concept through prototype burner design, pilot scale experiments at MIT and scale-up and commercial design by ABB-CE (ALSTOM) to applications in industrial and utility plant boilers. The principle that turbulence can be significantly damped in a rotating flow field with a strong positive radial density gradient was used to increase the fuel rich zone residence time in internally staged low NOx burners. The continuous interaction of ideas from laboratory experimental and computational studies with those from the commercial design and industrial scale tests played a pivotal role in the development of the final product, the commercial RSFC burner. Examples of application in gas, oil, and coal fired industrial and utility boilers are discussed.
Evaluation of Risk Assessment Methods: South Sumatra Gas Pipeline Case Study
Authors: Wisianto Arie , Putra Satya A.
Published: March 2009

The South Sumatra Gas Pipeline has a total length of 250 km and varies in pipe size. It delivers 250 MMSCFD gas from scattered gas fields to gas markets in Palembang, the industrial center in South Sumatra. The 16-inch Rambutan-Betung segment has ruptured three times. Based on these failures a maintenance program was conducted to avoid similar problems in other segments. These programs were accelerated inline inspection, rupture investigation using Fault Tree Analysis (FTA) method, failure analysis and evaluation of risk assessment methods. The evaluation of risk assessment methods addresses the following considerations: Is the risk assessment method that has been used applicable? Which risk assessment method is more accurate? What actions are necessary to improve risk assessment in the future? Risk assessment methods by AGA PIMAR (American Gas Association Methods for Prioritizing Pipeline Maintenance And Rehabilitation) and Kent. W Muhlbauer method were evaluated and compared. The evaluation was applied based on five conditions. These conditions are before failure/rupture, after rupture, after intelligent pigging, after failure analysis and condition before failures but having high potential land movement. The last condition was included because the failure analysis indicated that ruptured was caused by land movement (land slide). The risk assessment evaluation indicated that each of the assessment methods used was applicable and accurate for different pipeline conditions. For the South Sumatra Gas Pipeline AGA PIMAR was found to be more suitable for the segments evaluated. This evaluation concludes that there is no exact method for implementation of risk assessment; engineering judgment is required in the process.
Retrofitting Crack Arrestors on a Pipeline Converted From Liquid to Gas Service
Authors: Porter Patrick C. , Patrick Andrew J.
Published: March 2009

PETRONET undertook to evaluate the conversion of two liquid pipelines designed and constructed under ASME B31.4 to gas service under ASME B31.8. In a liquid pipeline, a rupture will result in small length of pipe (3 m–10 ft.) opening to release product and pressure. The same failure mechanism in a pipeline with gas service can be far more damaging. Under certain combinations of product, pressure, temperature and material, a rupture can result in a running fracture that can travel for miles. The releasing energy from the compressed gas can sustain the fracture mechanism until some barrier or material change can absorb the energy and allow the fracture to arrest. This can be the critical decision point in any planned service conversion. If the pipe material and operating conditions indicate that a running fracture may develop, then either the pipe has to be replaced or an arrest mechanism installed. The economics usually preclude pipe replacement so it becomes critical to develop a method of retrofitting suitable arrest units economically and safely. Clock Spring® Crack Arrestors have proven to be an economical solution to this challenge. This paper presents a case study of the conversion of a 457 mm (18-inch) pipeline, designed and constructed in accordance with ASME B31.4 for liquid service, to gas operation under ASME B31.8. The pipeline is located in South Africa and is operated by PETRONET. The use of Clock Spring® Crack Arrestors saved million dollars over pipe replacement and was a key issue in the economic justification of the conversion.
Development of a Procedure for the Calculation of J-R Curves From Pressed-Notch Drop Weight Tear Test Specimens
Authors: Rudland David L. , Wilkowski Gery , Wang Yong-Yi , Horsley David , Rothwell Brian , Glover Alan
Published: March 2009

Over the last few years, there have been ongoing efforts funded by TransCanada PipeLines Limited to develop a more fundamentally based procedure to extract a true measure of the dynamic steady-state fracture toughness of linepipe steels. As part of this effort, considerable research has focused on the drop-weight tear test (DWTT) specimen as the baseline specimen to be used in this development. Using instrumented DWTT test equipment, dynamic load-displacement histories were extracted from the experiments. In addition, a visual measure of the crack growth, and the crack-tip-opening angle (CTOA) were obtained from high-speed video equipment. A procedure has been developed using detailed three-dimensional finite element analyses that calculate the J-integral as a function of crack growth for these dynamic experiments. The results from these analyses have been verified using published procedures on similar scale specimens. This paper presents the development of a procedure for calculating the dynamic J-R curve from the load-displacement trace of a pressed-notch DWTT specimen. The slope of the JM-R curves generated provides technical insight into the range of steady-state propagation that occurs during these experiments. The slope of the JM-R curve (dJM/da) is compared to the visually measured CTOA values and conclusions about the relationship between these parameters and the steady-state propagation energy are made. These results are key in the development of a procedure to predict steady-state fracture propagation from laboratory specimen data.
American Society of Mechanical Engineers, B31.8 Committee Integrity Management Standard Supplement (B31.8S)
Authors: Zurcher John S. , Drake J. Andrew , Leewis Keith G.
Published: March 2009

Under the auspices of the American Society of Mechanical Engineers (ASME), a new standard supplement has been produced to aid operators in the development and implementation of an integrity management program. This new standard supplement will outline the technical requirements for implementation of an operator’s integrity management plan as well as the programmatic elements overall. Historically, integrity management has been an integral part of pipeline operations. Contained throughout ASME B31.8, integrity management requirements are specified. One purpose of this new supplement is to formalize a more deliberate process for the management of integrity and to push adoption of an industry consensus standard by the Office of Pipeline Safety. An ad-hoc task team was assembled earlier this year to develop the standard supplement. The task team consists of members from the Office of Pipeline Safety (OPS), from the National Association of Pipeline Safety Regulators, and from the gas transmission and distribution industry. With an opportunity to create a new standard, the task team was able to fundamentally and deliberately rethink the process and the protections provided. The standard supplement is the repository for twenty technical studies and reports completed by a variety of scientific and technical organizations. These studies and reports provide the technical platform for the standard supplement. It is anticipated that the standard will serve as a “hub” for many other standards, eight of which are presently under development. The B31.8 code was the predecessor to the pipeline safety regulations, which were first promulgated in 1970. The code is an international code and is approved by the American National Standards Institute (ANSI). It was felt that an ASME consensus standard would be the best home as the companion to the proposed regulations due to the strict policies of both ASME and ANSI for public comment, due process, and technical justification. The standard supplement provides guidance for two methods of compliance, a prescriptive track and a performance track. The prescriptive track will be very conservative but easier to implement. The performance track will be more flexible but will require significantly more data to implement. Within the standard supplement, the operator would have the option of following either track. This new standard supplement represents a new way for regulations, research and standards to be coordinated. It provides for performance based regulations referencing technically based standards that are developed from focused research.
The Design and Installation of the LEOS Leak Detection and Location System for the Northstar Project
Authors: Bryce Peter W. , Jax Peter , Fang Jie
Published: March 2009

The Northstar project is the first crude oil production facility constructed offshore in the Beaufort Sea. Produced crude oil is transferred via a buried subsea pipeline to shore and overland to the Trans Alaska Pipeline Pump Station PS1 facility. During the permitting process, concern was expressed that a very small chronic leak in the subsea oil line would remain undetected during the winter months of continuous ice cover. Therefore, the US Army Corps of Engineers stipulated that a prototype leak detection system be installed that would capable of detecting a threshold leak less than 32 BOPD. This paper addresses the efforts to develop and install the LEOS leak detection system for arctic operations. The system is based on the well-established LEOS leak detection technology (manufactured by Framatome ANP, formerly by Siemens AG). The system comprises a perforated plastic tube with a thin water impermeable acetate outer sheath that allows hydrocarbon molecules to diffuse into the air filled tube. The air inside the tube is replaced periodically (every 24 hours) and is passed through a hydrocarbon-sensing module. The module contains resistors sensitive to the presence of very small concentrations of hydrocarbon molecules. The presence and location of a leak is determined by measuring the time taken for the localized concentration of hydrocarbon molecules associated with a leak to reach the end of the tube. LEOS components and materials were engineered to survive installation during arctic winter conditions. It was also necessary to protect the plastic LEOS sensor tube as it was lowered through the ice, attached to the pipeline, into a pre-excavated trench and then backfilled. The 10km long LEOS tube was delivered to site in 31-coiled 300m (1000-ft) bundles that were transported from Germany to Alaska. The LEOS sensing tube was preinstalled in a protective outer polyethylene tube which was unreeled through a reverse bending jig. Crude oil production started at the Northstar production facility in October 2001 and the LEOS system has been operational since then and is providing the highest degree of assurance that no oil is escaping from the pipeline.
Solutions to Two Problems of Pipe Flow
Authors: Wu Shouhong , Ade Femi
Published: March 2009

This paper assesses two aspects of liquid flow in pipes. The first aspect is the relation between pipe critical flow depth and flow discharge. The critical flow depth in a pipe is generally expressed as an implicit function. The paper proposes two simple expressions that can be used to explicitly express pipe critical flow depth as a function of pipe diameter and discharge. The approximation errors associated with these proposed expressions were found to be within 1.0%. The second aspect is the flow transition from open pipe flow to full pipe flow in a long pipe. Theoretically, when a pipe is close to flowing full, a given discharge may correspond to multiple head differences. This paper presents a practical solution approach that yields a unique solution for the pipe flow depth for a given discharge in the transition zone.
Pipeline Project Implementation and Management Risk Analysis
Authors: Stripling Travis E. , Schneider Jochen
Published: March 2009

There currently exist documented project implementation risk analysis and management processes that can be applied to pipeline projects [1]. The more macro type methodology of Reference [1] can be combined with the more detailed analysis presented in this paper to achieve better management of project cost and schedule, and presents an opportunity for the pipeline industry to reduce overall project cost and schedule overruns. Given the significant number of very large, prospective pipeline projects in the world today, many with challenging economic viabilities, effective risk analysis and management may very well make the marginal difference if a particular project proceeds or not.
Efficiencies and Benefits Gained by Small Pipeline Companies From the Implementation of Cost-Effective GIS Technology
Authors: Jones Brent A.
Published: March 2009

Many smaller pipeline operating companies see the benefits of implementing a Geographic Information System (GIS) to organize pipeline data and meet the requirements of 49 CFR 195, but cannot justify the cost of a large-scale AM/FM/GIS system. PPL Interstate Energy Company (PPL IE) is a pipeline company with 84 miles of main that implemented a GIS solution that leverages both existing technology and facility data investments. This paper discusses the process used to acquire landbase data, to organize existing pipeline data from a variety of paper-based and digital sources, and to integrate these data sets. It will also discuss the functionality and benefits of the resultant GIS.
Refurbishment of a 230 KM Oil Pipeline With Longitudinal Seam Weld Fatigue Cracking Problem
Authors: Ledezma Marianela , Aranguren Jose´ G. , Paletta Fabrizio
Published: March 2009

Recently, a Petro´leos de Venezuela S. A. (PDVSA) oil pipeline, 230 Km (143 miles) in length and 660 mm (26 in.) in diameter, had a leak in the longitudinal seam weld of one of its sections. The analysis of this failure revealed that the leakage was originated in a fatigue crack which nucleated at a stress concentrator associated to a weld defect, and it propagated due to the cyclic stresses induced by the internal pressure changes. Partial external inspection of the pipeline revealed that the problem was extended to other sections. This paper summarizes the actions taken for the refurbishment of the oil pipeline which included: 1- the management plan set to face the problem; 2- the inspection of the pipeline, externally and internally; 3- the analysis of the inspection results; 4- the defect tolerance assessment / fitness-for-purpose study, to estimate both, the critical crack sizes as well as the crack propagation rates; 5- the development of repair procedures, and, 6- the determination of future inspection and maintenance recommended programs. All of it, with the main purpose of maintaining the operation of this line with complete guarantee of its integrity. Thanks to these actions, it has been possible to prevent additional failures in the same pipeline as well as to reduce in about MM$ 25 the maintenance cost associated with it.
The Pipeline Defect Assessment Manual
Authors: Cosham Andrew , Hopkins Phil
Published: March 2009

Oil and gas transmission pipelines have a good safety record. This is due to a combination of good design, materials and operating practices. However, like any engineering structure, pipelines do occasionally fail. The major causes of pipeline failures around the world are external interference and corrosion; therefore, assessment methods are needed to determine the severity of such defects when they are detected in pipelines. Defects occurring during the fabrication of a pipeline are usually assessed against recognised and proven quality control (workmanship) limits. These workmanship limits are somewhat arbitrary, but they have been proven over time. However, a pipeline will invariably contain larger defects at some stage during its life, and these will require a ‘fitness-for-purpose’ assessment to determine whether or not to repair the pipeline. Consequently, the past 40 years has seen a large number of full scale tests of defects in pipelines, and the development of a number of methods for assessing the significance of defects. Some of these methods have been incorporated into industry guidance, others are to be found in the published literature. However, there is no definitive guidance that draws together all of the assessment techniques, or assesses each method against the published test data, or recommends best practice in their application. To address this industry need, a Joint Industry Project has been sponsored by fifteen international oil and gas companies to develop a Pipeline Defect Assessment Manual (PDAM). PDAM documents the best available techniques currently available for the assessment of pipeline defects (such as corrosion, dents, gouges, weld defects, etc.) in a simple and easy-to-use manual, and gives guidance in their use. PDAM is based on an extensive critical review of pipeline fitness-for-purpose methods and published test data. It is intended to be another tool to help pipeline engineers maintain the high level of pipeline safety. In addition to identifying the best methods, PDAM has served to identify a number of limitations in the current understanding of the behaviour of defects in pipelines, and the empirical limits in the application of existing methods. This paper discusses the PDAM project, in the context of both the current best practice available for defect assessment and the limitations of current knowledge.
Possible Use of New Materials for High Pressure Linepipe Construction: An Opening on X100 Grade Steel
Authors: Barsanti L. , Mannucci G. , Hillenbrand H. G. , Demofonti G. , Harris D.
Published: March 2009

The increasing needs of natural gas, foreseen for the next years, makes more and more important the type of transportation chosen, both from strategic and economic point of view. The most important gas markets will be Northern America, Europe, Asia and Russia but the demand shall be fulfilled also by emerging producers as Kazakhstan, Turkmenistan and Eastern Siberia that at the moment are developing their resources in order to be competitive on Gas market. In this way producers and customers will be placed at greater and greater distances implying realization of complex gas transportation pipeline network, when use of LNG tankers is impossible or uneconomic. On the base of these considerations in 1997 began a feasibility study on X100 steel, given that, comparing different design approaches, it has been observed that consistent savings could be obtained by means of using high grade steel and high pressure linepipes. In this multi-sponsored project (Eni group, European Community of steel and Carbon, CSM, Corus and Europipe) CSM and Corus group were involved in the laboratory and full-scale pipes testing, Europipe was the pipes producer and Snam Rete Gas was involved in field weldability and technical coordination. No technical breakthrough, but only improvements in the existing expertise were involved in the X100 production; consequently, the production window is very narrow. However optimized steelmaking practices and processes enabled the material to reach the desired properties: strength, toughness and weldability. This paper is intended to present the general results arising from this project, in terms of steel properties (chemical composition, mechanical properties), ductile and brittle fracture resistance (results of full scale burst tests, West Jefferson tests) and field weldability, but above all the know-how stored till now on high grade steel and its possible use from a Gas company and a Pipe maker point of view.
Meta-Risk as a Method for Addressing Uncertainty in a Pipeline Risk Management System
Authors: Fenyvesi Louis , Rothwell Brian , Colquhoun Iain
Published: March 2009

Typical risk assessment processes produce risk estimates by multiplying together single-valued, expected failure frequencies and associated consequences. However, a range of consequences can result from an incident, and a more representative estimate of failure frequency is captured by a distributed variable rather than by a single point value. Risk estimates calculated by typical assessment processes are sometimes referred to as “mean” estimates or “cautious best estimates”. This terminology acknowledges implicitly that there is truly a range of possible values. Meta-risk is a potential approach for analyzing risk that captures this uncertainty by utilizing distributions of failure frequency and consequence in place of point estimates. These distributions are combined to form a risk distribution that can then be used more directly in quantified decision making. Meta-risk improves on the principle of “As low as reasonably practicable” (ALARP) by acknowledging that the levels of uncertainty associated with models used in the risk assessment process are not equal. By providing “probability of exceedance” targets relative to defined risk acceptance criteria, the meta-risk approach allows for quantified decision making that addresses both the level of risk and the associated level of uncertainty. This process allows an analyst to compare risks more accurately from multiple hazards between which levels of uncertainty may vary greatly, and to quantify the benefits of integrity management strategies such as condition monitoring whose primary effect is to reduce uncertainty rather than to reduce risk directly.
The Effect of the Slip Velocity on the Differential Pressure in Multiphase Venturi Flow Meters
Authors: Paladino Emilio E. , Maliska Clovis R.
Published: March 2009

Venturi tubes and orifice plates are devices largely used in the petroleum industry for measuring multiphase flows. In the project and calibration of these flow meters, the homogeneous model is commonly used. This model calculates the velocity and pressure drop of the mixture using correlations for single phase flow with a modified viscosity and density to account for the presence of the other phase, but no consideration is made about the relative velocity between the phases. However, the pressure difference, the measuring variable in these flow meters, is known to be affected by the relative velocity between phases, which becomes more and more important when the flow mixture accelerates. This paper addresses this issue and aims to demonstrate the importance of the slip velocity in the calculation of the flow velocity in a venturi meter. For this purpose, pressure-difference values obtained using the two-fluid model based on an Eulerian-Eulerian approach for the multiphase flow are compared with the results of the homogeneous model and with experimental data. Both theoretical calculations are performed using the CFX4.4 package, code which solves multidimensional multiphase flows. Considerations about the two-fluid model are presented, focusing, in particular, on the effects of the stress tensor in the dispersed phase. Considerations regarding the two-dimensional nature of the flow are also made. Test cases are presented in order to determine the dependency of the differential pressure with void fraction and slip velocity.