Integrity of Sour Gas Pipeline Despite Local Hard Zones

2018 ◽  
Author(s):  
Mamdouh M. Salama ◽  
Hernan Rincon ◽  
Stuart Wilson
Keyword(s):  
Fracture Resistance ◽  
Gas Pipeline ◽  
Premature Failure ◽  
Steel Pipes ◽  
The Impact ◽  
Sour Service ◽  
Sour Gas

The recent premature failure of TMCP steel pipes handling sour gas was attributed to the presence of local hard spots. This raised concern regarding the suitability of the Thermo-Mechanically Controlled Process (TMCP) steel for sour service. The paper discusses the impact of hard spots on pipeline fracture resistance in sour service, proposes a basis for steel specification to avoid the formation of hard spots and presents a recommended qualification program to ensure the integrity of the steel pipelines despite the presence of hard spots.

Response of Mild Steel Pipes Under High Mass Low Velocity Impacts

2014 ◽  
Author(s):  
Shamsoon Fareed ◽  
Ian May
Keyword(s):  
Finite Element ◽  
Mild Steel ◽  
Impact Energy ◽  
High Mass ◽  
Low Velocity ◽  
Element Analysis ◽  
Steel Pipes ◽  
Impact Tests ◽  
The Finite Element Analysis ◽  
The Impact

Accidental loads, for example, due to heavy dropped objects, impact from the trawl gear and anchors of fishing vessels can cause damage to pipelines on the sea bed. The amount of damage will depend on the impact energy. The indentation will be localized at the contact area of the pipe and the impacting object, however, an understanding of the extent of the damage due to an impact is required so that if one should occur in practice an assessment can be made to determine if remedial action needs to be taken to ensure that the pipeline is still serviceable. There are a number of parameters, including the pipe cross section and impact energy, which influence the impact behaviour of a pipe. This paper describes the response, and assesses the damage, of mild steel pipes under high mass low velocity impacts. For this purpose full scale impacts tests were carried out on mild steel pipe having diameter of 457 mm, thickness of 25.4 mm and length of 2000 mm. The pipe was restrained along the base and a 2 tonnes mass with sharp impactor having a vertical downward velocity of 3870 mm/sec was used to impact the pipe transversely with an impact energy of 16 kJ. It was found from the impact tests that a smooth indentation was produced in the pipe. The impact tests were then used for validation of the non-linear dynamic implicit analyses using the finite element analysis software ABAQUS. Deformations at the impact zone, the rebound velocity, etc, recorded in the tests and the results of the finite element analysis were found to be in good agreement. The impact tests and finite element analyses described in this paper will help to improve the understanding of the response of steel pipes under impact loading and can be used as a benchmark for further finite element modelling of impacts on pipes.

scholarly journals Challenges of Hot Tapping Into a Sour Gas Transmission Line

2000 ◽  
Author(s):  
Ray Goodfellow ◽  
Rory Belanger
Keyword(s):  
Transmission Line ◽  
Operating Conditions ◽  
New Production ◽  
Line Pressure ◽  
Welding Procedure ◽  
Sour Service ◽  
Line Temperature ◽  
Procedure Development ◽  
Design Pressure ◽  
Sour Gas

Chevron Canada Resources recently completed a hot tap on the Simonette high-pressure sour gas transmission line near Grande Prairie, Alberta. The hot tap was required to bring on new production into the Simonette pipeline without shutting in existing production. The hot tap was completed under full line pressure and gas/condenstate flow during the winter with temperatures averaging −20°C. The design pressure of the 12 “ Gr. 359 Cat II pipeline is 9930 kPa and the line operates at 8200 kPa. The gas in the main transmission line is approximately 2% H2S and 4% CO2. The gas being brought on through the 4″ hot tap tie-in was 21% H2S and 5% CO2. At the tie-in point the transmission line temperature was 3°C. Safely welding on the pipeline under these conditions was a considerable technical challenge. In welding sour service lines it is critical that the final weld hardness be below Vickers 248 micro hardness. This can be very difficult to achieve when welding on a line transporting a quenching medium of gas and condensate. In addition, hydrogen charging of the steel from operation in sour service can lead to hydrogen embrittlement during welding. Ludwig & Associates developed the hot tap weld procedure and extensively tested the procedure to ensure that suitable weld microhardness was achievable under pipeline operating conditions. As part of the procedure development the welder who would perform the hot tap was tested repeatedly until he could confidently and successfully complete the weld. During fieldwork, the welding was rigorously monitored to ensure procedural compliance thereby minimizing the possibility of elevated hardness zones within the completed weldment. This paper will detail with the technical development of the hot tap welding procedure and the successful field implementation.

scholarly journals Fracture resistance and 3D finite element analysis of machined ceramic crowns bonded to endodontically treated molars with two planes versus flat occlusal preparation designs: an in vitro study

F1000Research ◽  
2021 ◽  
Vol 8 ◽  
pp. 1020
Author(s):  
Omnia Nabil ◽  
Carl Hany Halim ◽  
Ashraf Hassan Mokhtar
Keyword(s):  
Stress Distribution ◽  
Fracture Resistance ◽  
Element Analysis ◽  
3D Finite Element ◽  
Mean Values ◽  
Group I ◽  
Group Ii ◽  
The Impact ◽  
Preparation Design ◽  
Distribution Of Stresses

Background: The flat occlusal preparation design (FOD) of posterior teeth offers promising results of fracture resistance and stress distribution, but its application in vital teeth is limited as there may be a danger of pulp injury. Although this danger is omitted in endodontically treated teeth, there is no research work assessing the impact of FOD on the fracture resistance and distribution of stresses among these teeth. The aim of this study was to assess the impact of FOD of endodontically treated molars on the fracture resistance and distribution of stresses among a ceramic crown-molar structure when compared to the two planes occlusal preparation design (TOD). Methods: 20 human mandibular molars were endodontically treated and distributed equally to two groups: Group I (TOD) and Group II (FOD). Ceramic CAD/CAM milled lithium disilicate (IPS e.max CAD) crowns were produced for all preparations and adhered using self-adhesive resin cement. Using a universal testing machine, the fracture resistance test was performed. The fractured samples were examined using a stereomicroscope and scanning electron microscope to determine modes of failure. Stress distribution was evaluated by 3D finite element analysis, which was performed on digital models of endodontically treated mandibular molars (one model for each design). Results: Group II recorded statistically non-significant higher fracture resistance mean values (3107.2± 604.9 N) than Group I mean values (2962.6 ±524.27 N) as indicated by Student’s t-test (t=0.55, p= 0.57). Also, Group II resulted in more favorable failure mode as compared to Group I. Both preparation designs yielded low von-Mises stresses within the factor of safety. However, the stress distribution among different layers of the model differed. Conclusions: FOD having comparable fracture strength to TOD and a more favorable fracture behavior can be used for the preparation of endodontically treated molars.

scholarly journals EFFECTS OF TEMPERATURE AND CHANGING DISINFECTANTS ON STEEL WATER PIPES CORROSION: CASE STUDY OF MASHHAD, IRAN

2020 ◽  
Vol 5 (2) ◽  
pp. 65-71
Author(s):  
Mobin Rahimi-Golkhandan ◽  
Shahnaz Danesh ◽  
Ali Davoodi
Keyword(s):  
Potassium Permanganate ◽  
Sodium Hypochlorite ◽  
Positive Impact ◽  
Water Disinfection ◽  
Decision Makers ◽  
Water Pipe ◽  
Steel Pipes ◽  
Water Pipes ◽  
Corrosion Of Steel ◽  
The Impact

Water pipe corrosion inflicts big health problems and financial damages to societies. Temperature, pH, type, and dosage of oxidants, and DO are some of the key factors that affect water pipe corrosion. The aim of this research is to assess the impacts of temperature (15 and 25oC), dosage of potassium permanganate (0, 1 and 2 mg/L) and sodium hypochlorite (0, 0.5 and 1 mg/L) on corrosion of steel pipes. To measure the corrosion of steel specimens, OCP, EIS and potentiodynamic polarization tests were conducted. The results showed a direct relationship between temperature and corrosion rate. A 10-degree raise in the temperature, caused a 25% increase in corrosion current density (CCD). Adding sodium hypochlorite to the solution, decreases CCD by around 50%. Moreover, potassium permanganate proved to have a positive impact on reducing CCD by up to 21%. The results demonstrate that simultaneous usage of NaClO and KMnO4 for water disinfection can have beneficial impact on corrosion of steel pipes. Finally, our analysis suggests that when combined with KMnO4, lower dosage of NaClO significantly increases polarization resistance. The findings of this research highlight the impact of disinfectants on steel water pipes corrosion in different temperatures and supports water infrastructure decision-makers in more effective rehabilitation and maintenance of water pipes. Further, our results inform decision-makers for a more effective infrastructure design and resilience planning to random failures caused by corrosion.

Dynamic Responses of Buried Pipelines Under Impact Loading Caused by Landslide

2012 ◽  
Vol 204-208 ◽  
pp. 3476-3479 ◽  
Author(s):  
Xiu Xing Zhu ◽  
Shi Feng Xue ◽  
Xing Hua Tong ◽  
Chuan Qi Liu
Keyword(s):  
Impact Loading ◽  
Impact Force ◽  
Large Diameter ◽  
Influence Factors ◽  
Dynamic Responses ◽  
Thin Wall ◽  
Buried Pipelines ◽  
Steel Pipes ◽  
Mountainous Regions ◽  
The Impact

Cases of pipeline damage caused by landslide are common in coastal or mountainous regions, where the design of buried pipelines should be improved in order to reduce the risk of damage or failure. Dynamic responses of large diameter thin wall steel pipes under impact loading were analyzed using a nonlinear contact model of pipe-soil coupling in this paper. Several influence factors were studied, such as the impact velocity of rockfall, buried depth of pipeline, ratio of diameter to thickness and style of soil. The results show that an ellipsoid induces much more impact force than a sphere which has the same volume, and the larger one in volume have greater impact force for two spheres. Dangerous compressive areas of pipeline occupy 1/6 of the whole area, so the pipelines subject to landslide occur local failure. Based on results, some useful suggestions for the design of pipelines in landslide region are given

An Experimental Study on the Lateral Impact of Fully Clamped Mild Steel Pipes

1992 ◽  
Vol 206 (2) ◽  
pp. 111-127 ◽  
Author(s):  
N Jones ◽  
S E Birch ◽  
R S Birch ◽  
L Zhu ◽  
M Brown
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Mild Steel ◽  
Failure Modes ◽  
Experimental Results ◽  
Lateral Impact ◽  
Drop Hammer ◽  
Steel Pipes ◽  
Scale Range ◽  
The Impact

This report presents some experimental data that were recorded from 130 impact tests on mild steel pipes in two drop hammer rigs. The pipes were fully clamped across a span which was ten times the corresponding outside pipe diameters which lie between 22 and 324 mm. All of the pipes except five had wall thicknesses of 2 mm approximately and were impacted laterally by a rigid wedge indenter at the mid span, one-quarter span or near to a support. The impact velocities ranged up to 14 m/s and caused various failure modes. Some comparisons between two sets of experimental results indicate that the laws of geometrically similar scaling are almost satisfied over a scale range of approximately five.

The Impact of the Ukraine Crisis on the Planning of Russian-European Natural Gas Pipeline Projects

2019 ◽  
Vol 98 (sp1) ◽  
pp. 392
Author(s):  
Zhihui Ma ◽  
Xinlei Pei ◽  
Yunfeng Yi ◽  
Yi Liu ◽  
Xiaotao Zhang
Keyword(s):  
Natural Gas ◽  
Gas Pipeline ◽  
Natural Gas Pipeline ◽  
Ukraine Crisis ◽  
The Impact

Failure Along Spiral Welds in Gas Pipeline

2016 ◽  
Author(s):  
Saleh Al-Sulaiman ◽  
Shabbir Safri ◽  
Abdul Salam ◽  
Chi Lee
Keyword(s):  
Stress Measurement ◽  
Gas Pipeline ◽  
Gas Oil ◽  
Stress Cracking ◽  
Failure Investigation ◽  
Oil Export ◽  
Sulfide Stress ◽  
Sulfide Stress Cracking ◽  
Operational Constraints ◽  
Sour Gas

A 16 km. long, 18” Gas pipeline (HP055) was in service to transport High Pressure Gas from an oil gathering center in West Kuwait (WK) area since 2001. The Pipeline carried wet sour gas. It was inspected in 2008 using high resolution MFL-ILI tool. No significant corrosion was found. In late 2012, a leak developed in the pipeline. The leak was due to a crack along a spiral weld on the bottom. Inspection during repairs revealed severe internal pitting on the bottom. The pipeline continued to leak several times in the next year, eventually resulting in decommissioning of the pipeline. Another ILI could not be carried out due to operational constraints and frequent leaks. The Pipeline was critical in the operation of the oil gathering center, and the loss of it severally affected the gas/oil export target and the flaring reduction commitment. An internal failure investigation was inconclusive, though indicating possibility of sulfide stress cracking. The failure investigation work was then entrusted to TWI, UK. A failed section of the pipeline was sent to their facilities and various tests including Chemical analysis, tensile test, residual stress measurement, SSC/HIC test, microstructure analysis, and analysis of corrosion products were carried out. The outcome of the tests and conclusion was very surprising. This paper describes in detail the leaks, inspection of leak locations, and the failure investigation findings and conclusions.

Experiment Study on Cutter Disrepair Principle and Optimization for Machining Heat-Resistant Steel

2012 ◽  
Vol 500 ◽  
pp. 58-64
Author(s):  
Yao Nan Cheng ◽  
Xian Li Liu ◽  
Fu Gang Yan ◽  
Zhen Jia Li ◽  
Xian Zhou Wang
Keyword(s):  
Mathematic Model ◽  
Resistant Steel ◽  
Experiment Study ◽  
Premature Failure ◽  
Heat Resistant Steel ◽  
Heat Resistant ◽  
Design Production ◽  
Milling Temperature ◽  
The Difference ◽  
The Impact

In order to find out the cutter disrepair principle and provide a valuable reference for the design, production and use of the heavy-duty hard alloy cutter, have experiment study on machining the heat-resistant steel-the 3Cr-1Mo-1/4Vsteel. First, have impact disrepair experiments with several types of different grooves milling inserts, and find out the difference of the impact disrepair invalidation types among them, and build the impact disrepair life cumulating distribution function mathematic model. Second, based on the adhering disrepair experiments, find out the difference of the adhering disrepair invalidation types, build the quantitative mathematic relation between milling temperature and maximal adhering disrepair depth on rake face of the cutter, and analyze the rule that the milling temperature affects the adhering disrepair. And then, on the basis of the scene machining, have analysis on cutter disrepair phenomenon and mechanism under the joint action of force and heat, so to provide a theoretical basis on how to avoid premature failure of the tool for the actual production process.

An Experimental Examination of the Effect of Interface Cooling on Thermal Wear Mechanisms in Carbon Graphite

2005 ◽  
Author(s):  
Daryl S. Schneider ◽  
Lyndon S. Stephens
Keyword(s):  
Heat Sink ◽  
Elevated Temperatures ◽  
Frictional Heating ◽  
Operating Conditions ◽  
Stable Operation ◽  
Mechanical Seal ◽  
Premature Failure ◽  
Thermally Induced ◽  
Wear Rates ◽  
The Impact

Premature failure of mechanical seal components is often a result of the elevated temperatures at the sealing interface that arise due to frictional heating. The Heat Sink Mechanical Seal (HSS) is a new approach to interface cooling in which a micro heat sink is constructed within millimeters of the sealing interface. Coolant circulated through the highly structured pin fin region carries away the generated heat. This work investigates the impact of interface cooling on carbon wear rates for a tungsten carbide (WC) and carbon graphite material pair. Experiments are performed using a thrust washer rotary tribometer to simulate a mechanical seal operating in dry running conditions within and in excess of the PV limit for the material pair (17.5 MPa*m/s or 500,000 psi*ft/min). Results show stable operation of sealing components in harsh operating conditions as well as the potential to reduce the occurrence of thermally induced wear and failure.

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