The Experts below are selected from a list of 9 Experts worldwide ranked by ideXlab platform
M. Wheeler - One of the best experts on this subject based on the ideXlab platform.
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Fatigue failure of outlet Pipe work of flare system at natural gas processing plant
13th International Conference on Fracture 2013 ICF 2013, 2013Co-Authors: A.-m. El-batahgy, M. WheelerAbstract:The natural gas produced from subsea wells is processed through different stages before being supplied through Pipelines for local market or export. Processing of the produced natural gas is started with separation of gas and liquid using a slug catcher that is connected to a flare system. The flare system consists of piping made of 16″ diameter branches connected to 20″ diameter header using circumferential weld with a total of seven joints. The Pipe work of the flare system is made of 316L stainless steel and it is operated in an interrupted mode. Design and operation pressures are 142 bar g and 88 bar g while design and operation temperatures are -40°C and 20°C, respectively. After five years of normal service, one of the seven joints of 16″ branch/20″ header has experienced failure. Based on different non-destructive and destructive tests, it is concluded that this premature failure is attributed mainly to fatigue damage. It is believed that acute or sharp angle of 16″ branch/20″ header connection that acts as a local stress raiser played a remarkable role in initiation of fatigue damage on outer surface, just beside circumferential weld. In addition, low stress high frequency vibration of the Subject Pipe work, due to mainly several emergency shut down operations, has accelerated initiation of fatigue damage. In order to minimize the possibility of such failure in future, design of 16″ branch to 20″ header connection was modified where a compensation plate fitted was used to minimize stress concentration at this connection zone.
A.-m. El-batahgy - One of the best experts on this subject based on the ideXlab platform.
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Fatigue failure of outlet Pipe work of flare system at natural gas processing plant
13th International Conference on Fracture 2013 ICF 2013, 2013Co-Authors: A.-m. El-batahgy, M. WheelerAbstract:The natural gas produced from subsea wells is processed through different stages before being supplied through Pipelines for local market or export. Processing of the produced natural gas is started with separation of gas and liquid using a slug catcher that is connected to a flare system. The flare system consists of piping made of 16″ diameter branches connected to 20″ diameter header using circumferential weld with a total of seven joints. The Pipe work of the flare system is made of 316L stainless steel and it is operated in an interrupted mode. Design and operation pressures are 142 bar g and 88 bar g while design and operation temperatures are -40°C and 20°C, respectively. After five years of normal service, one of the seven joints of 16″ branch/20″ header has experienced failure. Based on different non-destructive and destructive tests, it is concluded that this premature failure is attributed mainly to fatigue damage. It is believed that acute or sharp angle of 16″ branch/20″ header connection that acts as a local stress raiser played a remarkable role in initiation of fatigue damage on outer surface, just beside circumferential weld. In addition, low stress high frequency vibration of the Subject Pipe work, due to mainly several emergency shut down operations, has accelerated initiation of fatigue damage. In order to minimize the possibility of such failure in future, design of 16″ branch to 20″ header connection was modified where a compensation plate fitted was used to minimize stress concentration at this connection zone.
Edward L. Fronapfel - One of the best experts on this subject based on the ideXlab platform.
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Emissivity Determination and Temperature Calculation of Fluids in Piping Assemblies
2007Co-Authors: Bradley J. Stolz, Edward L. FronapfelAbstract:There has been little discussion about infrared ("IR") thermography's ability to determine the temperatures of heating liquids and gas within piping assemblies. Determining accurate emissivity values as related to the curvature of common Pipes is critical to accurate temperature determination. It is generally accepted that the emissivity of any non-blackbody object declines as the angle of incidence increases from zero degrees (perpendicular). This fact creates complications with respect to the accurate temperature evaluation of a section of Pipe due to the inherent curvature of common piping materials. We will discuss the determination of emissivity for various piping systems and provide explicit directions in order to aid the investigator during infrared inspections/surveys of heated piping assemblies. INTRODUCTION AND BACKGROUND The use of infrared thermography in determining the temperature of fluid in Pipes is a standard practice in the field of thermographers. The understanding of the geometry of the systems necessary to provide for proper evaluation of the readings is extremely important. It is understood that the emissivity of any object can vary by the inclination or angle of reading. The emissivity does in fact vary by the introduction of angle. The standard tables providing emissivity are provided for an angle of inclination of 90 degree or perpendicular to an object. In order to provide a better analysis and determination of results with thermography measurements, it is important to understand the relationships of the various products' emissivities. Also, the thermographer should understand the effects of the angle of inclination utilized when conducting thermographic surveys. This paper will deal with the determination of the values of emissivity of such common piping materials and the effect of the angle and distance of view used at the time of the thermographic imaging. The field use of the infrared camera for this application requires the thermographer to evaluate piping assemblies from various distances. Therefore, the curvature of the Pipe introduces an immediate issue: as the perimeter of the Pipe draws away from the center line, the angle of inclination is reduced from 90 degrees. The reduction in the angle of inclination will lower the apparent emissivity of the assembly. Because the spot size is essentially averaging an area of differing emissivities, the result is a lower overall emissivity value and an underestimated value for the temperature of the fluid. If a thermographer performs a thermal evaluation at a distance that minimizes the spot size (i.e., stands closer to the Pipe being analyzed), the spot size will be lessened and the angle of inclination will be close to 90 degrees. Conversely, if a thermographer is forced to stand at a greater distance from the Subject Pipe, the spot size is proportionally increased based on the camera's spot size ratio ("SSR") and the relative size of the piping material. The result is that the thermal image is distorted with the shape of the surface area as the cone of the spot begins to wrap over the cylindrical Pipe surface. The ensuing emissivity "distortion" is inherently nonlinear. That is, the area increases exponentially as a function of the spot size, making the prediction of its effects extremely difficult. Additionally, the angular effects on emissivity are different for every material, as discussed in Professional Investigative Engineer's 2006 Inframation paper, increasing the complexity of a general solution to this problem (materials with low emissivities are greatly affected by this scenario based on their high reflectivity). Figure 1 provides a visual representation of the changing emissivity and its relation to the spot size.
Bradley J. Stolz - One of the best experts on this subject based on the ideXlab platform.
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Emissivity Determination and Temperature Calculation of Fluids in Piping Assemblies
2007Co-Authors: Bradley J. Stolz, Edward L. FronapfelAbstract:There has been little discussion about infrared ("IR") thermography's ability to determine the temperatures of heating liquids and gas within piping assemblies. Determining accurate emissivity values as related to the curvature of common Pipes is critical to accurate temperature determination. It is generally accepted that the emissivity of any non-blackbody object declines as the angle of incidence increases from zero degrees (perpendicular). This fact creates complications with respect to the accurate temperature evaluation of a section of Pipe due to the inherent curvature of common piping materials. We will discuss the determination of emissivity for various piping systems and provide explicit directions in order to aid the investigator during infrared inspections/surveys of heated piping assemblies. INTRODUCTION AND BACKGROUND The use of infrared thermography in determining the temperature of fluid in Pipes is a standard practice in the field of thermographers. The understanding of the geometry of the systems necessary to provide for proper evaluation of the readings is extremely important. It is understood that the emissivity of any object can vary by the inclination or angle of reading. The emissivity does in fact vary by the introduction of angle. The standard tables providing emissivity are provided for an angle of inclination of 90 degree or perpendicular to an object. In order to provide a better analysis and determination of results with thermography measurements, it is important to understand the relationships of the various products' emissivities. Also, the thermographer should understand the effects of the angle of inclination utilized when conducting thermographic surveys. This paper will deal with the determination of the values of emissivity of such common piping materials and the effect of the angle and distance of view used at the time of the thermographic imaging. The field use of the infrared camera for this application requires the thermographer to evaluate piping assemblies from various distances. Therefore, the curvature of the Pipe introduces an immediate issue: as the perimeter of the Pipe draws away from the center line, the angle of inclination is reduced from 90 degrees. The reduction in the angle of inclination will lower the apparent emissivity of the assembly. Because the spot size is essentially averaging an area of differing emissivities, the result is a lower overall emissivity value and an underestimated value for the temperature of the fluid. If a thermographer performs a thermal evaluation at a distance that minimizes the spot size (i.e., stands closer to the Pipe being analyzed), the spot size will be lessened and the angle of inclination will be close to 90 degrees. Conversely, if a thermographer is forced to stand at a greater distance from the Subject Pipe, the spot size is proportionally increased based on the camera's spot size ratio ("SSR") and the relative size of the piping material. The result is that the thermal image is distorted with the shape of the surface area as the cone of the spot begins to wrap over the cylindrical Pipe surface. The ensuing emissivity "distortion" is inherently nonlinear. That is, the area increases exponentially as a function of the spot size, making the prediction of its effects extremely difficult. Additionally, the angular effects on emissivity are different for every material, as discussed in Professional Investigative Engineer's 2006 Inframation paper, increasing the complexity of a general solution to this problem (materials with low emissivities are greatly affected by this scenario based on their high reflectivity). Figure 1 provides a visual representation of the changing emissivity and its relation to the spot size.
Randy Mcgill - One of the best experts on this subject based on the ideXlab platform.
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Collapse Ratings of Cold Expanded Line Pipe Used as Casing
Day 1 Mon September 30 2019, 2019Co-Authors: Rich Miller, Craig Stewart, Oladele Owoeye, Abe King, Xin Long, Randy McgillAbstract:Abstract API Specification 5L (2018) Pipe is commonly used as surface casing. Recent deepwater failures have led to a review of collapse performance of 5L Pipe as part of the larger root cause investigation. A survey of Pipeline industry publications generated a database of over 80 collapse tests of cold-expanded line Pipe. The data are compared to casing collapse ratings per API Technical Report 5C3 (2018) and to alternative ratings included in API Recommended Practice 1111 (2015) for offshore Pipelines and in the submarine Pipeline standard DNVGL-ST-F101 (2017). The comparison showed that the Pipeline ratings provide a better fit to the collapse data and that API TR 5C3 overpredicts collapse performance of the Subject Pipe. Further investigation revealed that, for two operators, the vast majority of offshore surface casing is line Pipe that has been cold-expanded without stress relief. Several risk mitigation alternatives were considered. In the short term, the risk can be managed through learning bulletins, design guidelines and operational procedures. The preferred mitigation is to change the collapse rating for cold-expanded line Pipe used as casing. This is a long-term solution involving industry standards and the subsequent adoption through commercial design software. The work described in this paper has led to a ballot change for the next edition of API TR 5C3. This paper is presented to provide drilling industry awareness of the lower collapse performance of cold-expanded line Pipe and to add context for selection of an appropriate alternative rating.
