bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental and Numerical Investigations of Heating Up Processes of Fluids in Large Pools
Authors: Krepper Eckhard , Aszo´di Attila , Weiss Frank-Peter
Published: March 2009

Heating up experiments at the secondary pools side of the NOKO test facility were performed, to investigate mixed convection phenomena. The NOKO test facility was designed to investigate the heat transfer capability of an emergency condenser and was operated in the Research Centre Ju¨lich. In the Forschungszentrum Rossendorf the heating up tests were analyzed by CFD-simulations using the AEA-Technology code CFX-4. Applying the Boussinesq approximation the simulation of the heating up process is possible, at least qualitatively. Using the laminar approach, temperature oscillations caused by plumes could be simulated. A further test series performed at Forschungszentrum Rossendorf deals with the investigation of transient boiling. Heating up a 10 l water tank from the side walls, the temperatures and the void fractions at different locations in the tank were measured. CFX-4 simulations using the implemented boiling model reproduce and explain the observed phenomena. Convergence problems occurred with higher vapor volume fractions.
Biomass Boundary Layer Turbine Power System
Authors: Patel Nikhil , Schmidt Darren D.
Published: March 2009

A “Boundary Layer Turbine” (BLT), with a specially designed multiple-disk rotor consisting of a number of closely packed parallel disks fixed to the shaft, was used to demonstrate direct conversion of biomass for small-scale distributed power generation. The turbine operates under the effect of skin friction drag exerted on the parallel plates, resulting from the flow of hot gases between the parallel plates. This concept is well known for its resistance to erosion when pumping viscous fluids, and the technology has been developed for commercial pump applications but not for a turbine. The turbine based on this concept is capable of encountering particle-laden gas and can accept ash-containing biomass fuels. In the present experiments, wood-derived sawdust (particle size ∼1 mm) and natural oats were fired separately as the test fuels. These fuels were injected directly into the stream of vitiated hot air downstream of the combustor. The location of injection was based on a 1- to 3-second residence time for complete combustion. This paper discusses a performance study and assessment of deposition, erosion, and corrosion (DEC) effects on the working components of the BLT. The potential for cost-effective electricity production from biomass in distributed-generation applications is also explored. The BLT was operated for 40 hours, consuming 68 kg of biomass fuel. The testing included initial firing of 10% biomass (by heating value), increasing to 100%. Documented performance shows isentropic turbine efficiencies of 11% at 3.2 kW and 6284 rpm. Turbine inlet conditions averaged 2.8 bar and 645 K. Over the course of testing, no significant component degradation was observed. The hot components were coated with a small amount of soot, but no deposits were formed that would lead to plugging or buildup in the turbine housing. The results of the study represent the first step toward development of a biomass BLT. It has been demonstrated that no significant barriers should hamper the use of biomass fuels in the rotor; however, isentropic efficiencies will have to be improved to at least 50% to achieve meaningful overall cycle efficiency.
Water Recovery Systems for Steam-Injected Gas Turbines: Size Optimization and Life Cycle Savings
Authors: Blanco Gabriel , Ambs Lawrence L.
Published: March 2009

Steam injection in gas turbines has been used for many years to increase the power output as well as the efficiency of the system and, more recently, to reduce the formation of NOx during the combustion. The major drawback in steam-injection technology is the need of large amounts of fresh water that is eventually lost into the atmosphere along with the exhaust gas. This loss not only increases the operating costs of the system, but also creates other “external” costs in terms of environmental impacts. In order to take advantage of the steam-injection technology and reduce both operating costs and potential environmental impacts, water recovery systems to recuperate the injected steam from the exhaust gas can be implemented. This paper briefly describes the computer models developed at the University of Massachusetts Amherst to optimize water recovery systems. As an example, the optimum size, power requirement and capital cost for two different systems applied to the GE LM2500 gas turbine are shown. Finally, a comparative economic analysis between the costs of installing and operating a water recovery system and the costs of buying and treating water on a regular basis during the lifetime of the project is presented. The results support the economic feasibility of water recovery for mid-size steam-injected gas turbines before having introduced the external costs associated with the use of water resources.
Challenges and Solutions to Workforce Qualification at Power Generation Facilities
Authors: Garrity Russ
Published: March 2009

To be competitive in a “deregulated” market, power plant workers must be better qualified and more versatile than ever. Regardless of his or her area of expertise (operations, craft maintenance, plant controls, or other), tomorrow’s plant worker must be better skilled than ever before. Regardless of plant design, fuel type, or loading schedules, the defining difference in plant performance resides in the people who operate, maintain, and manage the plant. Whether it’s how they respond to abnormal operating conditions, how conscientious they are with plant chemistry, or how well they test and maintain critical components; it’s people, not equipment that make the difference between a well run facility and one with never ceasing problems. According to industry statistics, power generation facilities will loose between 30% and 50% of their most experienced workers over the next five years. This means that the people who hold the “tribal knowledge” of your facility will be leaving in the not too distant future. Furthermore, the availability of a trainable labor pool to replace the “Boomers” is in very short supply and difficult to recruit.
Experimental Results of an Ammonia-Water Mixture Turbine System: Part 2 — Effect of the Ammonia Mass Fraction
Authors: Takeshita Keisuke , Amano Yoshiharu , Hashizume Takumi , Usui Akira , Tanzawa Yoshiaki
Published: March 2009

This paper is an additional report to the paper by Amano (2001). In this paper, the authors report the additional experimental results of the effect of an ammonia mass fraction at the inlet of the AWM (Ammonia-Water Mixture) vapor generator in the AWM turbine system. The AWM turbine system features the Kalina Cycle technology. The 70KW-experimental facility was built in order to gain knowledge for practical applications. The heat source is the exhaust steam from a back-pressure steam turbine. The AWM turbine system is installed at the bottoming stage of a combined cycle which has a gas turbine, a steam turbine and an AWM turbine for cascade utilization of heat. The authors designed and constructed an experimental facility, the ACGS (the Advanced Co-Generation System), to investigate various energy-saving technologies for a distributed energy supply system in the Advanced Research Institute for Science and Engineering at Waseda University. One of the main targets is a hybrid combined heat and power supply system that uses AWM as its working fluid. The AWM turbine system was developed for the bottoming stage of a “trinary turbine cycle system” which is composed of a gas turbine, a steam turbine and the AWM turbine systems. The experimental results of the ammonia mass fraction to the cycle efficiency are investigated with a range of the ammonia mass fraction between 0.4 [NH3kg/kg] to 0.7 [NH3kg/kg]. It shows that there are optimal operating conditions depending on the heat source temperature with an ammonia mass fraction of the cycle. The simulation model of the AWM turbine system shows good agreement with the experimental data.
Use of CFD Modeling for Design of NOx Reduction Systems in Utility Boilers
Authors: Adams Bradley , Cremer Marc , Valentine James , Bhamidipati Venkata , O’Connor David , Letcavits J. J. , Vierstra Scott
Published: March 2009

CFD modeling has found increasing use in the design and evaluation of utility boiler retrofits, combustion optimization and NOx reduction technologies. This paper reviews two recent examples of CFD modeling used in the design and evaluation of NOx reduction technologies. The first example involves the staging of furnace combustion through use of overfire air (OFA) to reduce NOx emission in a B&W opposed-wall fired pc furnace. Furnace simulations identified locations of highest flue gas mass flows and highest CO concentrations and were used to identify OFA port placement for maximum NOx reduction with lowest increases in unburned carbon in fly ash and CO emission. Simulations predicted a 34% reduction in NOx emission with OFA. The second example summarizes the design and application of RRI with OFA and SNCR in a 138 MW cyclone-fired boiler. Simulations were used to design an aminebased injection system for the staged lower furnace and to evaluate NOx reduction and ammonia slip of the RRI system. Field-testing confirmed modeling predictions and demonstrated that the RRI system alone could achieve 25–30% NOx reduction beyond OFA levels with less than 1 ppm ammonia slip and that RRI in combination with SNCR could achieve 50–55% NOx reduction with less than 5 ppm slip.
Design and Construction of a Gas Turbine Engine to Test Validity of Hybrid Combustion Systems for Use in High Altitude Aircraft Propulsion
Authors: Fuchs Michael J. , Ebrahimi Nader D.
Published: March 2009

The purpose of designing and constructing this engine is to investigate the application of hybrid and alternative combustion systems as applied to gas turbine engines used for aircraft propulsion. The interest in this type of system comes from undesirable performance of gas turbine engines at extreme altitudes. The engine is a high-bypass, two-spooled turbofan with the inner spool and combustion system located on the outside of the fan bypass duct. This unusual arrangement is to allow greater flexibility in combustion system modifications as well as to better facilitate maintenance and modification work without disturbing the fan spool. The hope is to evaluate the feasibility of a hypothetical gas turbine jet engine specifically designed for use at extreme altitude. (Figure 1)
Utilization of Low Temperature Waste Heat for Cold TES
Authors: Rizza James J.
Published: March 2009

This paper presents an advanced energy cogeneration system that utilizes low temperature waste heat in the range of 60°C to 95°C to produce cold thermal energy storage (TES). Since there is usually a temporal variance between the availability of low temperature waste heat and demand for commercial building air conditioning, a cold TES system is incorporated into this advance energy system. The proposed TES system uses a lithium bromide/water solution both as a refrigerant and as a cold thermal storage material. The cold storage material can be stored at ambient temperature without thermal insulation for an indefinite period of time without losing its charge, making it an ideal system for utilizing peaking system’s low temperature waste heat or to utilize low temperature waste heat during nocturnal operation of continuous generation systems at a time when there are usually low or minimal air conditioning requirements. The heat pump and waste heat is used to recover the thermal storage by reprocessing the stored lithium bromide weak solution to a higher concentration.
Performance of Water Cannons at Labadie
Authors: Breeding Charlie , Ziegler Thomas W.
Published: March 2009

Amerens Labadie station consists of 4 coal fired 600 megawatt size generating units. Unit 1 installed water cannon furnace cleaning devices during a spring outage this year. Water cannons were selected to clean the deposits that result from combustion of Powder River Basin (PRB) coal at the Labadie power plant. This paper describes the evaluation of methods of cleaning furnace walls and the selection, installation, and startup experience with water cannons. Cleaning the furnace results in an increase in boiler efficiency that is translated into improved heat rate and improved cost of plant operation. Benefits from water cannon installation are described along with the problems encountered. PRB fuel combustion results in tenacious deposits that inhibit heat transfer on furnace walls. PRB coal typically has a lower ash fusion temperature than bituminous coals which leads to ash slag formation in furnaces that have been changed to PRB from the fuel the boiler was originally designed for. Often the deposit from PRB fuel is of a minimal thickness, however the reflectivity of the deposit creates a high barrier to radiant heat transfer. High Furnace Exit Gas Temperature (FEGT) indicates poor heat transfer in the furnace area and this increases the formation of slag in convection passes. Cleaning of furnace surface is critical to maximizing the heat absorption of the furnace and reducing the FEGT. The increased clean capability of the water cannons compared to existing wall blowers will be compared in this paper.
Several Case Histories of Generator Rotor Fan Failures and Methods of Repair
Authors: Moore William G.
Published: March 2009

Generators require cooling typically provided by one or two shaft driven rotating fans. These fans see large operating stresses due to rotational forces, shrink fit pressures, axial thrust forces, and thermal stress. Over time, fatigue cracks can develop in either the fan blade or root area, potentially leading to a catastrophic failure. Failure of a rotating fan inside a generator will cause extensive damage. The stored rotational energy in a fan that lets loose will typically destroy the stator winding, sometimes damage the stator core, and cause other damage to rotor components such as retaining rings, the rotor winding and possibly, even the rotor forging. This paper will be useful to power plant owners who have to maintain plant equipment and prevent failures of that equipment. A good understanding of the possible failure modes associated with rotating fans will enhance the emphasis on conducting good inspections of this equipment.
The Occurrence of Inorganic Elements in Various Biofuels and Its Effect on the Formation of Melt Phases During Combustion
Authors: Miller Sharon Falcone , Miller Bruce G.
Published: March 2009

The Pennsylvania State University is performing a feasibility analysis on installing a circulating fluidized bed (CFB) boiler at Penn State’s University Park campus for cofiring multiple biofuels and other wastes with coal. Twenty feedstocks are being considered. Chemical fractionation analysis was performed on eleven of the fuels. It is the objective of this paper to present the results of characterizing selected biomass fuels via chemical fractionation. The chemical analysis of the fuels is then used to determine the net ash composition of possible fuel blends and their propensity to form liquid phases during combustion based on thermodynamic modeling. The FactSage equilibrium calculations suggest that a cofire of biofuels with an appropriate non-fouling coal should not pose any problems in a CFB system given that the coal makes up a majority of the thermal input. FactSage consistently predicted K2Si4O9(l) to be present at 1171K with biofuels having low aluminum levels and significant concentration of alkali earth elements. Only 10% of K2O present in a system was enough to result in the formation of K2Si4O9(l) at equilibrium that could compromise a CFB system.
Role of Grain Boundaries in Intergranular Corrosion in Austenitic Stainless Steels
Authors: Wasnik D. N. , Kain V. , Samajdar I.
Published: March 2009

Grain boundaries play a very important role in intergranular corrosion. They determine whether the material is prone to intergranular corrosion or not. A study has been carried out to determine the influence of grain boundaries on the degree sensitization of Type 304 stainless steel (SS) and Type 316L stainless steel. The alloys were different thermomechanical treatment to obtain a variation in grain boundaries. They were then annealed and sensitized. The degree of sensitization was evaluated by using the Double Loop Electrochemical Potentiokinetic Reactivation (DL-EPR) technique and intergranular corrosion was evaluated by ferric sulfate-sulfuric acid test. In these tests, the degree of sensitization was measured by determining the ratio of the maximum current generated by a reactivation scan to that of the anodic scan, i.e. Ir: Ia, and intergranular corrosion was measured from weight loss of specimens. The grain boundary character distribution was measured with the help of Orientation Imaging Microscope (OIM). The degree of sensitization was then related to the grain boundary measurements. It was found that the degree of sensitization and intergranular corrosion is low at high angle grain boundaries in both types of stainless steel.
Predicting Corrosion Under Disbonded Coating Using Modeling and Cathodic Protection Monitoring Coupon
Authors: Sridhar N. , Dunn D. S. , Moghissi O. , King F. , Been J.
Published: March 2009

Coating defects generally take the form of either exposed bare steel or a disbondment, where a gap is formed between a relatively intact coating and bare steel. Cathodic protection can be difficult to achieve and monitor in the disbonded regions depending on the type of coating and soil conditions. Furthermore, stress corrosion cracking occurs predominantly under disbonded coatings. This paper describes a numerical modeling approach to predict the potential and chemistry under disbonded coating. In addition, the use of a monitoring coupon to simulate pipeline disbondments is demonstrated.
Pipelines Industry in India: Recent Developments and Future Requirements
Authors: Parekh Harsukh , Chandra Sati Vipin
Published: March 2009

The consumption of petroleum products in India has been growing at a high rate. In order to meet the growing demand for petroleum, additional refining capacity is planned to be created involving augmentation of some of the existing refineries and construction of new refineries. While the refineries will be in a position to meet the demand of petroleum products, the critical and vital issue will be to supply crude oil to the refineries and to reach the products to various consumption centers in an efficient, reliable and cost effective manner. In addition to the liquid petroleum, Natural Gas is emerging as the major source of energy/feedstock. Infrastructure for storage and transportation of Natural Gas are also required to be set up in a big way to meet the projected demand. This can best be done by constructing new pipelines which are recognized worldwide as the most reliable and cost effective mode of transportation of oil and gas. In addition to the requirement for new pipelines, there is a need for upgradation of technology in the existing cross-country pipelines, many of which are more than 20 years old. Moreover, Indian Government has, as part of the process of liberalisation of the economy through a series of measures focused on the infrastructural developments, technology upgradation, trade policies and financial reforms, has opened the core sector of Petroleum to private investment. Thus, considerable scope exists not only for consultants, equipment and material manufacturers/suppliers and contractors for providing their services but also for making investments in the Indian pipeline industry. This paper describes the prospects/opportunities in the Indian pipeline industry.
Double Block and Bleed and the Effects of Its Definitions on Pipeline Safety
Authors: Fournell J. A.
Published: March 2009

Double Block and Bleed (DBB) is the term commonly used to describe the systems or valving arrangements that provide double barrier pressure isolation of those performing work on a pipeline system downstream of the barrier. The consequences of releasing pipeline pressure downstream to an unsuspecting maintenance crew go without stating. If the risks are so high as to demand not single, but double barrier isolation between the fury of pipeline pressure and the safety of personnel and equipment, why then has it been so difficult to develop a consensus for the definition or description of DBB systems? This paper will explore in detail the internationally published definitions for DBB and analyze their merits with respect to pipeline safety. Definitions from organizations such as the American Petroleum Institute (API), Occupational Health and Safety (OHSA), the International Standards Organization (ISO) will be reviewed to determine what they contribute or fail to contribute to the intent of worker protection. Some Provincial Governments have written specific requirements for pipeline isolation into law, while others do not address the matter. These issues will also be explored and compared to the practices of companies operating oil and gas pipelines. Some insight on the division of definitions is offered through an understanding of the purposes or needs of the definer. For example, a valve manufacturer with a need to demonstrate that his valve will indeed block flow from both directions and thereby permit maintenance of the valve without removal from the pipeline may not fully appreciate the pipeline maintenance employee’s need to isolate himself from pipeline pressure by two independent barriers. It will be shown that standards and specifications are available to support both perspectives and that there are compelling reasons for deriving commonality between these perspectives. With the development of International Standards for oil and gas pipelines and increasing emphasis on the harmonization of various national standards, matters such as operator safety must not be compromised. Interesting opportunities exist to revisit topics such as definitions for DBB and perhaps derive a set of words that allows consensus and encompasses the true intent of the concept.
Development of Vibration Assessment and Screening Methods for Attachments to Pipeline Systems
Authors: Wastling Michael , Kroon Marc , Andrews Robert , Miles Toby
Published: March 2009

Pipeline systems incorporate numerous welded small bore attachments such as instrument connections or stabbings, vent and drain points and bypasses around full bore valves. These are susceptible to fatigue failure due to high frequency vibration excited both through the structure and by pressure fluctuations in the gas. Three examples of such fatigue failures are presented, showing that there may be several vulnerable welds in a connection. Detailed modelling of the potential consequences of the releases from such failures suggest that there may be situations in which unacceptable hazards may arise. Hence methods are described for rapid measurement of stresses in attachments, one based on accelerometers and the second on a frictional strain gauge system. Results from field measurements show how a simple screening criterion has been developed using established fatigue design methods to assess the results and identify cases requiring urgent action.
Measurement and Modelling of the Crack Tip Opening Angle in a Pipeline Steel
Authors: Andrews Robert , Chterenlikht Anton , Howard Ian , Yates John
Published: March 2009

Recent developments in the control of propagating ductile fractures in gas pipelines have proposed using the Crack Tip Opening Angle (CTOA) as a measure of fracture resistance. This is attractive as it can be related directly to the geometry of the fracturing pipe and also can be implemented easily in finite element models of the propagating fracture process. Current methods of determining CTOA in linepipe have been based on the standard DWTT specimen. This geometry often does not allow a fully slant fracture to develop, and is loaded in bending rather than tension. A novel specimen design has been developed to measure CTOA under quasi-static conditions and applied to a X80 (Grade 555) pipeline steel. The experimental work involved development of the design to ensure crack path stability. CTOA was obtained directly by measurement from video images. The CTOA values dropped from an initially high value to a steady state value of about 8 degrees when fully slant crack growth was achieved. This required crack growth over a distance of about 5 to 12 times the test section thickness. The crack growth was modeled numerically using the Gurson ductile void growth material model. The finite element modeling was able to qualitatively reproduce the crack path instability observed in practice, and the fall of CTOA from the initial high value to a steady state condition. Although further work is required to improve the modeling, the work carried out to date has demonstrated that there is the potential to apply damage mechanics methods to predict the laboratory specimen response and then to model the structural response.
Keihin Kansen Mainline: A Typical Urban Pipeline in Japan
Authors: Kawabata Shin-Ichiro , Takagi Nobuo , Yanagi Yukichi
Published: March 2009

The KEIHIN KANSEN pipeline of Tokyo Gas Co. Ltd., the construction of which was decided in 1986, has finally been completed after a long design and construction period of 13 years. KEIHIN KANSEN is a typical urban pipeline connecting Tokyo and Yokohama, the most crowded cities in Japan. This paper outlines the plan and concept of safety, and quality of the pipeline. Here are in particular described the piping works within the Keihin/ Asahi tunnel by shield method, focusing on its design scheme, study results, and experiments on pipeline supports for large reaction force.
Advanced Methodology for Complex Pipeline Optimization Problems
Authors: Stripling Travis E. , Ostrofsky Benjamin , Elgohary K. B.
Published: March 2009

During the life cycle design and implementation of a pipeline system, there exist a number of opportunities for system optimization analysis. Such analysis has traditionally involved the use of linear programming and simulation techniques. However, these approaches have limitations as more complex problems are considered with more involved and complex criteria. The Ostrofsky Design-Planning Optimization Morphology (OD-POM) is especially powerful because it can handle non-linear objective functions including probabilistic variables. This approach allows the assessment of the interaction among the criteria so that consideration can be given to each criteria as independent. Because of its rigor and sophistication, the methodology compares alternatives in a much more accurate manner for the given data than less comprehensive approaches (for example, linear programming). This example includes the subjective criteria, explicitly in a quantifiable manner and allows the evaluation of the relative importance of the criteria.
Security for Pipeline Assets: The State of the Art
Authors: Rizkalla Moness , Brown Jeff
Published: March 2009

The North American energy pipeline system represents a security challenge. Taking a holistic view of the problem allows the operator to construct and implement a strategy systematically. The solution involves a multi-disciplinary approach using a combination of business tools and technology to provide enhanced protection, and rapid restoration and recovery in the event of an attack. • Mapping of “high consequence” areas, including pipeline segments near population centers, water resources, or environmentally sensitive regions, will allow energy companies to more logically allocate security resources, but there may remain vast stretches of pipeline where physical barriers are impractical. • Formal decision analysis techniques can be effectively used to assess potential threats, analyze vulnerabilities, prepare contingency plans and set priorities. • Hardware elements of the solution will draw heavily upon technological innovations, including the use of active earth observation imagery and sophisticated sensing equipment for surveillance and early detection. • Strategic planning exercises will allow operators to think through the problem before a threat occurs and to put in place resources to react to a threat and to respond, restore, and recover from an attack. This is particularly true in coordination across a region. The expanding effort to safeguard the continent’s energy infrastructure will rely upon a greater level of (1) government-industry cooperation, particularly in the areas of data and information collection/analysis/dissemination, (2) technological adaptation/innovation, including greater use of sensing and surveillance technologies, (3) the development of financial and insurance products that fit the specific needs of energy asset owners and operators, (4) communication with key constituencies: customers, suppliers, regulators, law enforcement agencies, and financial markets, (5) customized training for employees, (6) government supervisory and enforcement authority to inspect and penalize companies that do not implement the appropriate level of security, while providing a due diligence safe harbor for those that are proactive; and (7) an unwavering commitment to protect vital assets, human, physical, and otherwise. It is critical that pipeline security programs focus on long-term, sustainable solutions that are customized to fit the specific needs of particular energy asset networks. The paper contains a specific example of pipeline infrastructure management system and display screen examples.
Mining for Knowledge: Revealing the Secrets of Information
Authors: Gloven Michael P.
Published: March 2009

Improvements in technology to capture, manage, and store ever increasing amounts of electronic data within the oil and gas pipeline industry presents new challenges in discovering the meaning and relevancy of this data in the management of pipeline integrity. Companies expend a significant level of resources in integrity data management at the time of pipeline installation, during integrity assessment work and on-going compliance, maintenance and operational activities. The meaning or interpretation of this data is typically revealed through expert team based discussion, tabular and graphical reporting or the direct application of operator-defined hypothesis or queries to reveal knowledge. Over the last several years, new processes and techniques have been developed to discover relevancy in large, disparate databases as often found within pipeline operations. This paper will discuss one of these new processes for discovering knowledge from data.
InfoPAE: An Emergency Plan Deployment System
Authors: Carvalho Marcelo Ti´lio Monterio de , Casanova Marco Antonio , Torres Fla´vio , Santos Aˆngelo
Published: March 2009

InfoPAE is an automated system designed to improve the response to emergency situations. The system offers sophisticated action plans, easy access to vital information and tight control over the resources allocated to face an emergency. The system is currently in use at Petrobras and its subsidiaries, incorporating the company’s technical experience. The system is applicable to pipelines, oils terminals, oil refineries and offshore installations, and it also proved to be a valuable training tool.
The Influence of Land Use and Depth of Cover on the Failure Rate of Gas Transmission Pipelines
Authors: Jager Eric , Kuik Robert , Stallenberg Gerard , Zanting Jeroen
Published: March 2009

The first stage in performing a risk calculation is the failure rate assessment. In order to get reliable risk calculations, a good understanding of the failure rate of an underground pipeline is indispensable. Earlier studies already showed that extra cover significantly reduces the likelihood of damage caused by third party interference. This paper describes the influence of depth of cover based on the latest information on incidents. Moreover, the influence of population density on the damage rate of pipelines is studied.
Soil-Structure Interaction of Heated Pipeline Buried in Soft Clay
Authors: da Costa Alvaro Maia , de Oliveira Cardoso Carlos , dos Santos Amaral Claudio , Andueza Alejandro
Published: March 2009

Heated pipelines buried in soft clay can develop a very challenging behavior. The thermal expansion of the pipelines normally induces buckles, which will be supported by the passive soil reaction. The buckles of the pipelines in soft clay can generate a non-linear inelastic behavior that is an unstable situation named “snap through”. In such situation the pipeline can jump from a configuration of a few centimeters displacement to another of meters displacement. Once the snap through situation has developed, there is the possibility of a local pipeline buckling, causing the pipeline rupture and as a consequence an oil spill. This paper presents the results obtained during the analysis of the rupture of a buried heated pipeline in the Guanabara Bay of Rio de Janeiro, Brazil. A very sophisticated procedure including a simulation of the thermal mechanical interactions between the soil and the pipeline structure was developed for back analysis of the thermal inelastic pipeline buckling. Computer modeling was carried out using the finite element method considering of the non-linear material behavior of the soil and pipeline, and nonlinear geometrical behavior of the pipeline. A cyclic thermal-mechanical soil-pipeline structure interaction model was the challenging aspect of the simulation, that explains the trigger mechanism of the snap through behavior of heated pipelines, which was responsible for the rupture of the pipeline in Guanabara Bay.
Channel Instability Problems at Two Pipeline River Crossings in Alberta
Authors: Malcovish Craig D. , Janz Artur H.
Published: March 2009

This paper describes the history of channel changes and associated pipeline exposure problems at two major river crossings in western Alberta. Each case history reviews the hydrologic and geomorphic factors that contributed to the exposure problem, discusses the various repair options that were considered, and describes the corrective action that was taken. Fisheries-related regulatory requirements had a major impact on the proposed remediation plans and are also discussed.
A Numerical Study of Dispersed Air Bubbles in a Hydrotransport Pipeline Flow
Authors: Wang C. D. , Eskin D. , Leonenko Y. , Lezhnin S. , Vinogradov O.
Published: March 2009

Different flow pattern maps and theoretical models were employed to determine the flow velocity needed to provide the dispersed-bubble flow in a hydrotransport pipeline. Comparison and analysis of the results has been carried out. The maximum and minimum bubble sizes were determined by semi-experimental methods. A log-normal function was employed to describe the bubble size distribution. A model for the bubble size change in the turbulent pipe flow was applied to study the evolution of the overall bubble size distribution. This model takes into account the competing factors influencing the bubble size: 1) dissolution (turbulent diffusion) of air in the liquid, causing bubble shrinkage; 2) pressure drop along the pipeline, causing bubble growth. Numerical analysis shows that the bubble dissolution rate strongly depends on the initial air hold-up and initial bubble size. An increase of air hold-up leads to a fast decrease of the dissolution rate. At sufficient high air hold-ups, the dissolution effect becomes negligible and air bubble sizes are dominantly controlled by the pressure drop. Smaller bubbles have higher dissolution rates than larger ones. Compared with a pure liquid flow under the same flow conditions, the effect of air hold-up is stronger in the slurry flow because of the smaller volume occupied by the liquid.
The Oil and Gas National Master Stations of Transpetro: Design and Implementation
Authors: Mackie Kevin , de Tarso Arruda Correia Paulo , Shinzato Alberto Mitsuya , Venancio Julio Cesar Barreto
Published: March 2009

This paper presents the design and implementation of Transpetro’s national master station project for oil and natural gas. The national master stations allow the centralized operation of Transpetro’s entire liquid and natural gas pipeline grid from their new headquarters in Rio de Janeiro. The implementation strategy includes transferring operations of the existing regional master stations — four for oil and two for gas — to the national master. Two of the regional masters are maintained as backups for the oil and gas national master stations, respectively. The project foresees the total deactivation of the existing regional master stations as their operations are migrated to the national master. The national master stations complement Transpetro’s integrated oil and gas SCADA systems.
Natural Hazard and Risk Management for South American Pipelines
Authors: Porter Michael , Savigny K. Wayne
Published: March 2009

Hazard identification and rating involve the first two of a four-phase natural hazard and risk management (NHRM) system that is being developed to manage natural hazards along linear facilities. In Canada, completing these first two phases is generally straightforward. Baseline data including air photos, geology and topographic maps are readily available; the number and types of hazard exposure are often limited for any given facility; and, the standard of care expected during design and construction is understood and practiced. The NHRM methodology is also being applied on South American pipelines. Greater flexibility is required in obtaining necessary input data. Helicopter and vehicle access are often more limited, and greater reliance must be placed on airphoto interpretation and literature review. Processes of rating hazard exposure are needed for less familiar hazard types, including tsunami, volcanic eruption, and tectonic ground rupture. South American construction and design practices must be accounted for in the rating methodology. Using examples from recently constructed trans Andean pipelines, this paper outlines application of the NHRM system to linear facilities located in areas of diverse hazard exposure and less stringent design and construction practices. Under the broad headings of ‘geotechnical’ and ‘hydrotechnical’ hazards, a methodology for rating eleven different hazard types is outlined. On the geotechnical side, these include tsunami, volcanic eruption, tectonic ground rupture, landslides and debris flows originating off-rights-of-way, and mass movements originating on rights-of-way. Hydrotechnical hazards include scour, degradation, bank erosion, encroachment, and channel abandonment/avulsion.
Viability of the Gas Pipeline Network Expansion in Brazil
Authors: dos Santos Sidney Pereira
Published: March 2009

The energy shortage in Brazil prompted for the need of alternative and reliable energy sources that could be put into operation in a short period of time while being environmentally friendly and with flexibility to be installed around the country, taking advantage of the existing electric grid and therefore minimizing overall investments. Gas fired power plants proved to be the best selection, which covered all the requirements. The Ministry of Mines and Energy of Brazil set a program addressing initially 55 thermo power plants totaling about 20,402 MW. From this total 18,263 MW of installed power was from 49 gas fired power plants demanding gas volumes in the range of 88 MMm3/d most of this power to be available from 2001 to 2003. With this challenge, Petrobras has started to design a gas pipeline network expansion plan with investments of more than 1 billion US$ for its system alone, including new gas pipelines, new compressor and custody transfer stations and loop lines. In line with this expansion project more investments are required for the Bolivia-Brazil Gas Pipeline in Bolivia (0.2 billion US$) and Brazil (0.35 billion US$), and the new gas pipeline from Argentina to Brazil (0.25 billion US$) totaling 1.8 billion US$ of additional investments in gas pipeline expansion. All of this expansion design was based on technical and economic analysis that took into consideration the availability of gas supply from Brazil, Bolivia and Argentina. This paper presents the scope of the expansion, the technical and economical assumptions and the hydraulic simulation that was used to allow an investment decision.
Pipeline ALIAS: A Universal Nomenclature System for the Pipeline Industry
Authors: McDonnell Shamus , Simmons Robert
Published: March 2009

Currently there is no universally accepted nomenclature system used in the pipeline industry. Typically each vendor or operator uses their own terminology based on relevant codes, training, and experience. This creates a problem when correlating Inline Inspection data with Non Destructive Evaluation and Metallurgical Sectioning results. This paper’s intention is to introduce a classification system that is independent of both vendor & operator specific terminology. In developing this universal nomenclature system, the authors consulted various pipeline operators and related regulatory bodies, as well as other publicized nomenclature sources. Once all the terms were compiled they were then merged, classified, and indexed. This indexed classification system will reflect the abilities and limitations of the three inspection methods and how they relate to each other so that proper correlation can be achieved.
Global Hydroelastic Response of a Catamaran Due to Wetdeck Slamming Accounting for Forward Speed
Authors: Ge Chunhua , Faltinsen Odd M. , Moan Torgeir
Published: March 2009

Global response of a flexible catamaran due to wetdeck slamming in head sea regular waves is studied. A 6DOF structural model is used to model the test catamaran. The catamaran has a wetdeck with horizontal transverse cross-sectional shape. The flow due to the water impact is assumed 2D in the longitu-dinal cross-sectional plane. Both a direct method and a modal based method are applied to predict the global response. Vertical shear forces and bending moments are compared with experimental data and show reasonable agreement. Theoretical and experimental error sources are presented and the influence on global response is discussed.
Gas and Water Permeation in Flexible Pipes
Authors: Andersen Tore Roberg , Skar Jan Ivar
Published: March 2009

A test program has been performed to obtain the permeation coefficients for methane, carbon dioxide and water in PVDF. Small-scale tests showed that water is transported through the PVDF inner sheath of the flexible pipes, and into the annulus. A large-scale test was carried out to verify the small-scale test results. It was performed in a 2″ flexible pipe with length 3 m. The bore temperature and pressure were 100°C and 50 bar, respectively. The pipe was submerged in cold water in order to get a correct temperature gradient in the pipe. The test showed that the annulus of flexible pipe with PVDF inner sheath would become water wet due to permeation, depending upon the bore and annulus conditions.
Ageing of PA 11 Pipes in CO2 Medium: A Tool to Predict Their Residual Lifetime
Authors: Thominette F. , Merdas I. , Verdu J.
Published: March 2009

The study of polyamide 11 hydrolysis in acid medium has a great importance taking into account the presence of CO2 pressure in the fields. Experimentally we have put in evidence that CO2 accelerates PA 11 hydrolysis and shift the equilibrium towards high conversions. Theoretically, two mechanisms can be involved in the CO2 effect on hydrolysis: - a catalytic effect by H+ ions (acceleration of the hydrolysis reaction); - an amine scavenging by CO2 (shift of the equilibrium towards high conversion) From this mechanistic scheme we propose a kinetic model. Then, we have built a computer program allowing to made all the calculations needed in practice by the users as the average molar mass and the residual lifetime for given conditions.
Burst Tests on Pipeline With Nonuniform Depth Corrosion Defects
Authors: Benjamin Adilson C. , Freire Jose Lui´z F. , Vieira Ronaldo D. , de Castro Jaime T. P.
Published: March 2009

PETROBRAS is conducting a research project with the purpose of investigating the behavior of pipeline with long nonuniform corrosion defects. In the first phase of this project, burst tests of two tubular specimens were carried out. Each of the two specimens had one external nonuniform depth corrosion defect, machined using spark erosion. The specimens were cut from longitudinal welded tubes made of API 5L X60 steel with an outside diameter of 323.9 mm and a nominal wall thickness of 9.53 mm. Each of the two tubular specimens was instrumented with 17 post-yield strain gages rosettes, one displacement transducer and two pressure transducers. This paper describes the tubular specimens tested and the instrumentation used. The measured burst pressures are compared with those predicted by the ASME B31G and the RSTRENG Effective Area methods. The material properties used were determined by tests of tensile specimens. Photographs of the fractured defects are presented along with comments about their differences in shape. Some values of strain measured during the tests are also presented and commented.
Anchor Deployment Planning Using Simulated Annealing
Authors: Augusto Oscar Brito
Published: March 2009

In this work a planning methodology for deep-water anchor deployment of anchor lines for offshore platforms and floating production systems aiming at operational resources optimization is explored, by minimizing a multi criteria objective function. A Simulated Annealing Algorithm was used to optimize the objective function. As an additional advantage, inherited from the proposed methodology, the planning automation is achieved. Planning automation overcomes the traditional way based on trial error exercise, where an engineer using an anchoring application, decides how much of work wire and anchoring line must be paid out from both the floating system and the supply boat and additionally which horizontal force must be applied to the line trying settle the anchor on a previously defined target in the ocean floor. Some cases, from anchor deployment of some MODUs operating in deep-water oil fields in Brazil, are shown demonstrating some potentialities of the proposed model.
Hydroelastic Behavior of Air-Supported Flexible Floating Structures
Authors: Ikoma Tomoki , Masuda Koichi , Maeda Hisaaki , Rheem Chang-Kyu
Published: March 2009

A pontoon type very large floating structure has elastic deformations in ocean waves. The deformation is larger than that of a semi-submergible type one. Thus, a pontoon type one will be installed to tranquil shallow water field enclosed by breakwaters. Moreover, a semi-submergible one will be applicable to development at offshore field. The authors has developed a pontoon type VLFS with an OWC (oscillating water column) type wave energy absorption system. This can be install to offshore field being deep water relatively. Such VLFS can reduce not only the elastic deformation but also the wave drifting forces. However, it is very difficult to reduce the wave drifting forces effectively because an effect of the reduction depends on the wave energy absorption. Therefore, the authors propose an air supported type VLFS. This idea has been already proposed. However, it wasn’t handled a flexible structure. Such an air-supported structure makes to transmit many waves. Therefore, the wave drifting forces may not increase. In addition, the elastic deformation may decrease because pressure distribution due to the incident waves becomes constant at the bottom of the structure, i.e. the pressure is constant in a same air chamber. We develop the program code for the analysis of the hydrodynamic forces on the VLFS with the air cushion. The potential flow theory is applied and the pressure distribution method is used to the analysis of the wave pressures. The zero-draft is assumed in this method. The pressure and volume change of the air cushion are linearized. In this paper, basic characteristics of the elastic deformations of the air-supported flexible floating structures are investigated. We confirm the effectiveness, and discuss behaviors of the water waves in air chamber areas.