Towards an Acceptable Pipeline Integrity Target Reliability

2016 ◽  
Author(s):  
Sherif Hassanien ◽  
Len Leblanc ◽  
Alex Nemeth
Keyword(s):  
Unit Length ◽  
Probability Of Failure ◽  
Operating Conditions ◽  
Probabilistic Methods ◽  
Pipeline System ◽  
Reliability Engineering ◽  
Safety Level ◽  
Main Challenge ◽  
Pipeline Segment ◽  
The Impact

Integrity reliability analysis is becoming an important component of effective pipeline integrity management systems. It aims at utilizing reliability engineering to address integrity uncertainties and check pipeline reliability measures against safety objectives/targets. In current practice, pipeline safety is typically verified using simplified deterministic procedures based on a safety factor approach that is tailored to the design of new pipes. A more realistic verification of actual safety performance of existing pipelines can be achieved by probabilistic methods where uncertainties of basic random variables are considered and the impact on the reliability of the system is analyzed. To enable such an approach, specification of integrity target reliability levels is required in order to benchmark the safety level of an existing pipeline system. The probability of failure (PoF) per pipeline segment or unit length is quantified and then checked against an integrity permissible probability of failure (PoFp) or integrity target reliability (1-PoFp). This check against a specified reliability target allows the operator to confidently determine whether a segment of pipe is safe at current operating conditions while considering identified uncertainties. However, the main challenge around reliability targets is choosing such targets to begin with. This paper presents a semi-quantitative validation approach for estimating integrity reliability targets based on calibrating past failure incidents and evaluating PoF at the time of failure. Accounting for both aleatory and epistemic uncertainties in assigning the integrity targets, pipeline operators can gauge how to choose such targets and how to be flexible in terms of customizing integrity targets based on their asset performance and adopted integrity programs. A brief summary of published reliability targets in pipeline and non-pipeline industries is presented herein.

Reliability of Buried Pipeline Using a Theory of Probability of Failure

2006 ◽  
Vol 110 ◽  
pp. 221-230 ◽  
Author(s):  
Ouk Sub Lee ◽  
Dong Hyeok Kim ◽  
Seon Soon Choi
Keyword(s):  
Failure Probability ◽  
Probability Of Failure ◽  
Operating Conditions ◽  
Reliability Estimation ◽  
Design Parameters ◽  
Buried Pipeline ◽  
Safety Level ◽  
First Order ◽  
Reliability Method ◽  
Corrosion Defects

The reliability estimation of buried pipeline with corrosion defects is presented. The reliability of corroded pipeline has been estimated by using a theory of probability of failure. And the reliability has been analyzed in accordance with a target safety level. The probability of failure is calculated using the FORM (first order reliability method). The changes in probability of failure corresponding to three corrosion models and eight failure pressure models are systematically investigated in detail. It is highly suggested that the plant designer should select appropriate operating conditions and design parameters and analyze the reliability of buried pipeline with corrosion defects according to the probability of failure and a required target safety level. The normalized margin is defined and estimated accordingly. Furthermore, the normalized margin is used to predict the failure probability using the fitting lines between failure probability and normalized margin.

Probabilistic Inspection Optimization of Free-Span Surveys for Subsea Gas Pipelines

2002 ◽  
Author(s):  
Jens P. Tronskar ◽  
Gudfinnur Sigurdsson ◽  
Olav Fyrileiv ◽  
Olav Forli ◽  
Joseph H. Kiefer ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Cracks ◽  
Probabilistic Methods ◽  
Material Strength ◽  
Pipeline System ◽  
Unstable Fracture ◽  
Girth Welds ◽  
The Impact

Probabilistic methods have been used to develop the basis for free-span inspection of a gas pipeline system in the South China Sea. The objective of the probabilistic analysis was to study the probability of fatigue failure associated with postulated planar flaws in the HAZ of repair welds performed on some of the girth welds. The impact of flaws on the fatigue life under different free-span conditions were studied. Conventional free-span analysis involves computation of allowable free-span lengths based on onset of in-line vibrations and does not normally consider fatigue crack growth. To consider the effect of the weld flaws on the failure probability a combined probabilistic fatigue and fracture model is required. For the particular pipelines analysed automatic ultrasonic testing (AUT) was used replacing the conventional radiography of the girth welds. Conservatism in the free-span assessment can then be significantly reduced by taking into account detailed flaw sizing information from the AUT. The inspection records provide distribution of flaw height, length and position. Combined with information on current distribution, material strength and fracture toughness distribution, a detailed probabilistic fatigue crack growth and unstable fracture assessment can be conducted as per the Det Norske Veritas (DNV) 2000 Rules for Submarine Pipeline Systems [1] using the response models of the DNV Guideline 14 for free-span analyses [2]. The objective of this analysis is to estimate the critical free-span lengths and the time for fatigue cracks to penetrate the pipe wall.

A Midstream Pipeline Operator’s Perspective on the Implementation of API 1183

2020 ◽  
Author(s):  
Jeremiah Konell ◽  
Brian Dedeke ◽  
Chris Hurst ◽  
Shanshan Wu ◽  
Joseph Bratton
Keyword(s):  
Selection Process ◽  
Management Program ◽  
Operating Conditions ◽  
Metal Loss ◽  
Pipeline System ◽  
Stress Risers ◽  
Integrity Management ◽  
Primary Focus ◽  
Condition Assessments ◽  
The Impact

Abstract In preparation for the upcoming (currently in draft form) Recommended Practice (RP) on Dent Assessment and Management (API 1183) [1], Explorer Pipeline Company, Inc. (Explorer) has performed an internal procedural review to determine how to effectively implement the methodologies into their Integrity Management Program (IMP). Explorer’s pipeline system transports hazardous liquids and is comprised of over 1,800 miles of pipeline ranging in diameter from 3 to 28 inches. The majority of the system was installed in the 1970s, but parts of the system were also installed as early as the 1940s. The primary focus of this review and implementation into the IMP is in regard to performing and responding to in-line inspection (ILI) based integrity assessments. Prior to the development of API 1183, dent assessment and management consisted of following a set of prescriptive condition assessments outlined in the Code of Federal Regulations (CFR) Title 49, Part 195.452. In order to do this, pipeline operators required basic information, such as dent depth, orientation, and interaction with potential stress risers such as metal loss, cracks, gouges, welds, etc. However, in order to fully implement API 1183, additional parameters are needed to define the dent shape, restraint condition, defect interaction, and pipeline operating conditions. Many new and necessary parameters were identified throughout the IMP, from the very initial pre-assessment stage (new ILI vendor requirements as part of the tool/vendor selection process) all the way to defining an appropriate reassessment interval (new process of analyzing dent fatigue life). This paper summarizes the parameters of API 1183 that were not part of Explorer’s current IMP. The parameters are identified, and comments are provided to rank the level of necessity from “must have” to “beneficial” (e.g. can sound and conservative assumptions be made when a parameter is not available). Comments are also provided to explain the impact of applying assumptions in place of parameters. The table of identified parameters should provide a useful tool for other pipeline operators who are considering implementing API 1183 as part of their overall IMP.

Achieving Consistent Safety by Using Appropriate Safety Factors in Corrosion Management Program

2020 ◽  
Author(s):  
Mohammad Al-Amin ◽  
Shenwei Zhang ◽  
Shahani Kariyawasam ◽  
Jason Z. Yan ◽  
Tammie Matchim
Keyword(s):  
Human Error ◽  
Pressure Ratio ◽  
Probabilistic Approach ◽  
Assessment Model ◽  
Metal Loss ◽  
Pipeline System ◽  
Operating Pressure ◽  
Safety Factors ◽  
Safety Level ◽  
The Impact

Abstract Pipeline operators assess metal-loss corrosion anomalies identified on pipelines to determine whether such anomalies require remediation. The assessment of metal-loss anomalies can be performed using deterministic or probabilistic approach. In deterministic method, the failure pressure ratio (FPR) for a metal-loss corrosion anomaly is evaluated against a predetermined safety factor, where FPR is defined as the predicted burst pressure of the anomaly divided by the maximum allowable operating pressure (MAOP) or maximum operating pressure (MOP). Conservative characteristic values are used for the variables such as measurements of metal-loss, pipe geometry, material properties, operating pressure and assessment model in calculating FPR. Safety factors in deterministic assessment are used to account for residual uncertainties, human error and consequence levels. Safety factors are established in various codes and standards in North America. However, those safety factors are not consistent across codes and standards as demonstrated in this paper. This paper describes the fundamentals of how appropriate safety can be assured for pipelines containing metal-loss anomalies by selecting appropriate safety factors. The effect of using different safety factors on the reliability level of the pipeline system is examined in this study. A set of new safety factors to ensure consistent safety level for pipelines containing metal-loss corrosion are proposed in this paper. The impact of the proposed safety factors on the integrity decisions are also demonstrated.

Reliability Based Pressure Containment Uprating

2013 ◽  
Author(s):  
Elie Dib ◽  
Sherif El-Gebaly ◽  
Frank Drennan
Keyword(s):  
Structural Reliability ◽  
Probabilistic Approach ◽  
Probability Of Failure ◽  
Operating Conditions ◽  
Current Status ◽  
Pipeline System ◽  
Design Life ◽  
Target Probability ◽  
Fit For Purpose ◽  
The Cost

Over the design life of long tiebacks, project requirements may change in order to accommodate new prospects. These new prospects may have design conditions exceeding those used for the rest of the field and the existing facilities may not be able to withstand the potential increases in pressure arising from new wells. For smaller and accidental increases, the existing system may be proven to be fit for purpose by using a probabilistic approach, or a structural reliability assessment. This approach may eventually reduce the cost of the new prospect by, for example, removing the need for an over-pressure protection system, or removing the need for a dedicated pipeline system. This paper investigates the potential increase in pressure capacity of a main pipeline for an accidental over-pressure condition using a structural reliability analysis and probabilistic approach using as-built data gathered from several projects. The variations on the as-built pipeline properties, the current status of the existing pipeline, and the corresponding operating conditions are taken into account using a Monte Carlo simulation. The results present a burst pressure with an indication of a safety factor and associated with a probability of failure. A comparison between the final results and the pipeline codes target probability of failure is also performed and presented as part of this paper.

scholarly journals Study of the impact of NPP rated thermal power uprate on process behavior at different transient conditions

2018 ◽  
pp. 9-13 ◽  
Author(s):  
A. G. Nikulenkov ◽  
D. V. Samoilenko ◽  
T. V. Nikulenkova
Keyword(s):  
Power Unit ◽  
Thermal Power ◽  
Operating Conditions ◽  
Life Assessment ◽  
Feed Water ◽  
Dimensional System ◽  
Residual Service Life ◽  
Safety Level ◽  
Coolant Pump ◽  
The Impact

Today, objective preconditions have been formed to find the ways on how to increase cost-effectiveness of NPPs operation, while providing the required safety level. One of such ways to increase thermal nominal power of power unit. The paper provides for the results of reactor behavior analysis at increased thermal power above nominal received using a one-dimensional system computer code RELAP5/MOD3.2 and relevant model of VVER-1000 (V-320) power unit. Calculation analyses are performed for quasi-static reactor operating conditions and transients using realistic approach in terms of initial performance parameters of reactor installation. In researches, representative initial events for transients have been selected according to the principle described further. For an abnormal operation, an event has been selected based on its high frequency and consequences, which require decreasing reactor power down to 50 % of nominal thermal power. For emergency conditions an event has been selected which is caused by external extreme impacts typical for Ukrainian NPP sites resulting in the worst consequences. Thus, the transients are represented by events associated with failure of a single turbine-driven feed water pump and total station blackout unit. To analyze emergency conditions caused by long-term blackout, they were additionally accompanied by a leakage through reactor coolant pump seals. Given that increase of steam flow in a turbine at increased thermal power above nominal requires additional studies on residual service life assessment of its critical components, a 3-D model of high-pressure rotor of a full speed turbine is proposed for further studies. Based on the calculations a comparative analysis of major parameters of the reactor at rated and increased thermal power is performed with assessment of significant factors to be considered in further studies on increase of installed thermal output of NPP unit.

Hydrogen in Pipelines: Impact of Hydrogen Transport in Natural Gas Pipelines

2020 ◽  
Author(s):  
Rainer Kurz ◽  
Matt Lubomirsky ◽  
Francis Bainier
Keyword(s):  
Natural Gas ◽  
Gas Turbines ◽  
Supply And Demand ◽  
Operating Conditions ◽  
Pipeline System ◽  
Pure Hydrogen ◽  
Hydraulic Simulation ◽  
Natural Gas Pipelines ◽  
Natural Gas Pipeline ◽  
The Impact

Abstract The increased use of renewable energy has made the need to store electricity a central requirement. One of the concepts to address this need is to produce hydrogen from surplus electricity, and to use the existing natural gas pipeline system to transport the hydrogen. Generally, the hydrogen content in the pipeline flow would be below 20%, thus avoiding the problems of transporting and burning pure hydrogen. The natural gas – hydrogen mixtures have to be considered both from a gas transport and a gas storage perspective. In this study, the impact of various levels of hydrogen in a pipeline system are simulated. The pipeline hydraulic simulation will provide the necessary operating conditions for the gas compressors, and the gas turbines that drive these compressors. The result of the study addresses the impact on transportation efficiency in terms of energy consumption and the emission of green house gases. Further, necessary concepts in the capability to store gas to better balance supply and demand are discussed.

The Impact of Electricity Losses on the Reliability of Electrical Equipment in the Rural Power Grid of 0.4 kV

2021 ◽  
Vol 1 (42) ◽  
pp. 34-38
Author(s):  
Gennadiy Kudryashev ◽  
◽  
Aleksandr Tret’yakov ◽  
Oksana Shpak
Keyword(s):  
Power Grid ◽  
Electrical Equipment ◽  
Probability Of Failure ◽  
Operating Conditions ◽  
Research Purpose ◽  
Electricity Supply ◽  
Industrial Complex ◽  
Electric Motors ◽  
Agricultural Enterprise ◽  
The Impact

Rural networks are characterized by a large length and low load density. In the country, there are problems with the reliability of electricity supply to agricultural enterprises and the uninterrupted operation of electrical equipment. The average duration of consumer outages is up to 100 hours annually. In Western developed countries, it is statistically defined as an acceptable state of electricity supply, when for a medium- voltage network during the year, the total duration of interruptions is in the range of 15-60 minutes per year. The permanent functioning of the Russian agro-industrial complex is impossible without reliable and stable operation of rural electric distribution networks. (Research purpose) The research purpose is in studying the impact of electricity losses on the reliability of electrical equipment in the rural power grid of 0.4 kilovolt. (Materials and methods) The methods of ensuring reliability include: design features of the system, reliability of electrical equipment; provision of backup power, system management tools, organization of operation. The reasons for the decrease in reliability were: equipment failures, errors of operating personnel, excess of resource capabilities, deviation of the actual operating conditions of the equipment from the calculated ones. (Results and discussion) The article considers the issues of additional electricity losses in the low- voltage network of 0.4 kilovolts on the example of the power supply of an agricultural enterprise, caused by the flow of reactive energy. The article presents graphs of phase voltages and power consumption. Authors conducted experimental studies in a network of 0.4 kilovolts. The article presents the calculated reliability indicators of electrical equipment at an agricultural enterprise. The increase in reliability when installing a compensating device in the 0.4 kilovolt network are described. (Conclusions) The increase of reliability of electrical equipment is revealed, the probability of failure operation of the electric motors decreased by 3 percent; the probability of failure operation of the electric motors decreased by 19 percent; reducing the failure rate by 15 percent; decrease in failure rates by 14 percent.

Truck Tire Operating Temperatures on Flat and Curved Test Surfaces

2005 ◽  
Vol 33 (3) ◽  
pp. 156-178 ◽  
Author(s):  
T. J. LaClair ◽  
C. Zarak
Keyword(s):  
Flat Surface ◽  
Operating Temperature ◽  
Operating Conditions ◽  
Load Pressure ◽  
Truck Tire ◽  
Endurance Testing ◽  
Operating Temperatures ◽  
The Impact ◽  
Tread Rubber ◽  
Cylindrical Test

Abstract Operating temperature is critical to the endurance life of a tire. Fundamental differences between operations of a tire on a flat surface, as experienced in normal highway use, and on a cylindrical test drum may result in a substantially higher tire temperature in the latter case. Nonetheless, cylindrical road wheels are widely used in the industry for tire endurance testing. This paper discusses the important effects of surface curvature on truck tire endurance testing and highlights the impact that curvature has on tire operating temperature. Temperature measurements made during testing on flat and curved surfaces under a range of load, pressure and speed conditions are presented. New tires and re-treaded tires of the same casing construction were evaluated to determine the effect that the tread rubber and pattern have on operating temperatures on the flat and curved test surfaces. The results of this study are used to suggest conditions on a road wheel that provide highway-equivalent operating conditions for truck tire endurance testing.

A NEW WELDING MATERIAL FOR REGENERATION IN THE WELDING TECHNOLOGY BASED ON NICKEL. ANALYSIS OF THE COMPOSITION AND PROPERTIES OF DEFORMABLE HEAT-RESISTANT HIGH-CHROMIUM NICKEL-BASED ALLOYS FOR WELDED PARTS. ANALYSIS OF EXISTING FUELLING STATIONS TYPES AND VEHICLES USING HYDROGEN, HYDROGEN PRODUCTION AND STORING METHODS

2019 ◽  
pp. 43-48
Author(s):  
Ben Nengjun ◽  
Zhou Pengfei ◽  
Oleksandr Labartkava ◽  
Mykhailo Samokhin
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Nickel Alloys ◽  
Total Content ◽  
Operating Conditions ◽  
High Temperature Strength ◽  
High Chromium ◽  
Salt Corrosion ◽  
Tcp Phases ◽  
The Impact

This work involves an analysis of high-chromium high-temperature deformable wieldable nickel alloys for use in GTE repair assemblies. It is shown that the alloys EP868 (VZh98) and Haynes 230 can be used in welded assemblies with an operating temperature of 800-1100 °C. The alloys Nimonic 81, Nimonic 91, IN 935, IN 939, and Nicrotan 2100 GT also have a high potential for use in welded assemblies. They are characterized by a combination of good weldability, high-temperature strength, and resistance to scaling. There have been conducted studies on high-temperature salt corrosion of model nickel alloys. They allowed establishing the patterns of the impact of base metal alloying with chromium, aluminum, titanium, cobalt, tungsten, molybdenum, niobium, tantalum and rare earth metals on the critical temperature of the start of salt corrosion Tcor and the alloy mass loss. It has been established that alloys with a moderate concentration (13-16%) of chromium can possess satisfactory hightemperature corrosion resistance (HTC resistance) under the operating conditions of ship GTE. The HTC resistance of CrAl-Ti alloys improves upon reaching the ratio Ti/Al ˃ 1. Meanwhile, the ratio Ti/Al ˂ 1 promotes the formation of corrosion products with low protective properties. The positive effect of tantalum on the HTC resistance of alloys is manifested at higher test temperatures than that of titanium, and the total content of molybdenum and tungsten in alloys is limited by the condition 8Mo2 – 2W2 = 89. The presence of refractory elements stabilizes the strengthening phase and prevents formation of the ɳ-phase. However, their excess promotes formation of the embrittling topologically close packed (TCP) phases and boundary carbides of an unfavorable morphology. Based on the studies of the HTC resistance, there has been identified a class of model high-temperature corrosionresistant nickel alloys with a moderate or high chromium content (30%), Ti/Al ˃ 1, and a balanced content of refractory and rare-earth elements.

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