scholarly journals Mechanical Development of a NPS 36 Speed Controlled Pipeline Corrosion Measurement Tool

Author(s):  
Robert S. Evenson ◽  
Scott K. Jacobs

High pressure natural gas pipeline companies conducting in-line magnetic flux leakage (MFL) corrosion inspection operations had to significantly reduce gas throughput velocity to accommodate MFL corrosion tool inspection speeds. A large bypass, variable speed NPS 36 MFL corrosion inspection tool has been developed and run successfully in several high pressure natural gas pipelines without noticeable impact on operational throughput Active speed control enables the tool to run at speeds significantly lower than line velocity commonly experienced in high pressure natural gas pipelines. Unique mechanical innovations include large diameter flow bypass, an efficient speed control mechanism, variable drag backing bars and an independent bypass override system. A floating backing bar system ensures uniform sensor/wall contact for optimum data collection. Magnetic self-levitation of the backing bar results in reduced load on suspension and wheels providing more reliability and longer life to these components. Operating in higher line velocities infers higher possible tool speeds. This potential required development and construction of a more durable tool capable of higher speeds than typical MFL corrosion inspection tools. In this paper, development, testing and field operation of this tool is described.

Author(s):  
Kevin Cicansky ◽  
Glenn Yuen

This Paper presents the method TransCanada PipeLines uses to assess the integrity risks with respect to operating its high pressure natural gas pipelines. TransCanada PipeLines’ experiences, results and successes gained through the implementation of its risk program, TRPRAM (TransCanada Pipelines Risk Assessment Model) are highlighted.


Author(s):  
Joe Zhou ◽  
Brian Rothwell ◽  
Wenxing Zhou ◽  
Maher Nessim

Two example onshore gas pipelines were designed using a reliability-based approach. The first example (1219 mm, 17.2 MPa) represents a high-pressure large-diameter pipeline; the second example has a smaller diameter (762 mm) and lower pressure (9.9 MPa). Three steel grades (X70, X80 and X100) were used to develop three design solutions for each example. The wall thickness-related life cycle costs of the designs were evaluated. The design outcomes show that the reliability targets for both examples can be met using X100 steels and high equivalent design factors (0.93 for the first example and 0.9 for the second example). Moreover, ruptures and excessive plastic deformation of a defect free pipe were found to be insignificant integrity threats even when the design uses X100 and relatively high equivalent design factors such as 0.85 and 0.9. The economic assessment results show that the X100 design is the most economical option for the high-pressure large-diameter example. However, using X100 does not show a clear economic advantage over using X80 for the second example mainly because the wall thickness for the design using X100 is governed by the maximum D/t ratio constraint. The study also demonstrates the advantages of the reliability-based approach as a valuable tool in assessing the feasibility and potential benefits of using high-grade steels on a pipeline project.


Author(s):  
S. M. Suleiman ◽  
Y. G. Li

Natural gas pipeline plays an important role in transporting natural gas over a long distance. Its performance and operating behavior are affected by many factors, such as ambient conditions, natural gas flow rate, operation and control of compressor pumping stations, etc. Better understanding of the performance and behavior of an integrated pipeline-compressor system used for gas transmission will be beneficial to both design and operation of natural gas pipelines. This paper introduces a novel steady-state thermodynamic performance simulation approach for natural gas pipelines based on fundamental thermodynamics with the inclusion of the coupling between a pipeline and compressor pumping stations. A pipeline resistance model, a compressor performance model characterized by an empirical compressor map and a pipeline control schedule for the operation of an integrated pipeline-compressor system are included in the simulation approach. The novel approach presented in this paper allows the analysis of the thermodynamic coupling between compressors and pipes and the off-design performance analysis of the integrated pipeline-compressor system. The introduced simulation approach has been applied to the performance simulation of a typical model pipeline driven by multiple centrifugal compressor pumping stations. It is assumed in the pipeline control schedule that the total pressure at the inlet of compressor stations is kept constant when pipeline operating condition changes. Such pipeline operating conditions include varying ambient temperature and varying natural gas volumetric flow rate. The performance behavior of the pipeline corresponding to the change of operating conditions has been successfully simulated. The introduced pipeline performance simulation approach is generic and can be applied to different pipeline-compressor systems.


2013 ◽  
Vol 401-403 ◽  
pp. 2170-2174 ◽  
Author(s):  
Ya Ping Yang ◽  
Yong Mei Hao ◽  
Zhi Xiang Xing

A Bayesian network quantitative calculation model for urban natural gas pipelines was established by using the unique logic of a Bayesian network in handling complicated risk systems. By using a natural gas pipeline as an example, failure situations such as single factor polymorphism, double factor polymorphism, and multi-factor polymorphism of a pipeline were quantitatively calculated to obtain the probability of top events and the structural importance of basic factors. The proposed method not only reflects clearly the effects of different factors but also predicts the failure state of urban natural gas pipelines comprehensively and accurately. The results of the proposed method can serve as a significant reference for the risk management and fault processing of city natural gas pipelines.


Gases ◽  
2021 ◽  
Vol 1 (4) ◽  
pp. 156-179
Author(s):  
Abubakar Jibrin Abbas ◽  
Hossein Hassani ◽  
Martin Burby ◽  
Idoko Job John

As an alternative to the construction of new infrastructure, repurposing existing natural gas pipelines for hydrogen transportation has been identified as a low-cost strategy for substituting natural gas with hydrogen in the wake of the energy transition. In line with that, a 342 km, 36″ natural gas pipeline was used in this study to simulate some technical implications of delivering the same amount of energy with different blends of natural gas and hydrogen, and with 100% hydrogen. Preliminary findings from the study confirmed that a three-fold increase in volumetric flow rate would be required of hydrogen to deliver an equivalent amount of energy as natural gas. The effects of flowing hydrogen at this rate in an existing natural gas pipeline on two flow parameters (the compressibility factor and the velocity gradient) which are crucial to the safety of the pipeline were investigated. The compressibility factor behaviour revealed the presence of a wide range of values as the proportions of hydrogen and natural gas in the blends changed, signifying disparate flow behaviours and consequent varying flow challenges. The velocity profiles showed that hydrogen can be transported in natural gas pipelines via blending with natural gas by up to 40% of hydrogen in the blend without exceeding the erosional velocity limits of the pipeline. However, when the proportion of hydrogen reached 60%, the erosional velocity limit was reached at 290 km, so that beyond this distance, the pipeline would be subject to internal erosion. The use of compressor stations was shown to be effective in remedying this challenge. This study provides more insights into the volumetric and safety considerations of adopting existing natural gas pipelines for the transportation of hydrogen and blends of hydrogen and natural gas.


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