Practical Methodology of Predictive Maintenance for Pipelines

2010 ◽  
Author(s):  
S. A. Timashev ◽  
A. V. Bushinskaya
Keyword(s):  
Wall Thickness ◽  
Pipe Wall ◽  
Residual Life ◽  
Real Life ◽  
Life Time ◽  
Predictive Maintenance ◽  
Operating Pressure ◽  
Pipe Material ◽  
Remaining Life ◽  
Corrosion Rates

Predictive maintenance (PdM) is the leading edge type of maintenance. Its principles are currently broadly used to maintain industrial assets [16]. Yet PdM is as yet not embraced by the pipeline industry. The paper describes a comprehensive practical risk based methodology of predictive maintenance of pipelines for different criteria of failure. For pipeline systems the main criterion is integrity. One of the main causes of loss of containment is pipe wall defects which grow in time. Any type of analysis of pipeline state (residual life time, probability of failure (POF), etc.,) is based on the sizes of discovered defects, which are assessed during the ILI or DA. In the developed methodology pipeline strength is assessed using one of the five internationally recognized design codes (the B31G, B31mod, DNV, Battelle, Shell 92). The pipeline POF is calculated by the comprehensive Gram-Charlier-Edgeworth method [14]. Having in mind that the repair actions are executed on particular cross-sections of the pipeline, the POF are calculated for each defect present in the pipeline. When calculating POFs, the defect sizes (depth, length and width), wall thickness and pipe diameter, SMYS of the pipe material, the radial and longitudinal corrosion rates, and operating pressure (OP) are considered random variables each distributed according to its PDF. In the proposed method of PdM of pipelines the remaining life time can be assessed using following criteria: POF = Qth; dd = 80%wt; SMOP = MAOP; ERF = MAOP/SMOP, if ERF ≥ 1, the pipeline needs immediate repair; dd = 100%wt. Here Qth is the ultimate permissible POF, dd is the depth of the most dangerous defect, wt is pipe wall thickness, SMOP is the maximal safe operating pressure SMOP = DF·Pf, MAOP is the Maximum Allowable Operating Pressure, Pf is the failure pressure, DF is the design factor (for B31Gmod DF = 1.39), ERF is the Estimated Repair Factor. The above criteria are arranged in descending order according to the growing level of their severity in time. The prediction of future sizes of growing defects and the pipeline remaining life time are obtained by using consistent assessments of their corrosion rates CRs. In the PdM methodology these CRs may be considered as deterministic, semi-probabilistic or fully stochastic values. Formulas are given for assessing the CRs using results of one ILI, two consecutive ILI, with or without verification measurements, and for the case when several independent types of measurements are used to assess the defect sizes. The paper describes results of implementation of the developed methodology on a real life pipeline. The time to reach each of the limit states given above was calculated, using results of two consecutive ILI divided by a three year interval. Knowledge of these arrival times permits minimizing the maintenance expenditures without creating any threats to its integrity and safety.

Markovian Analysis of Aging Distributed Systems Remaining Life

2014 ◽  
Author(s):  
Anna Bushinskaya ◽  
Sviatoslav Timashev
Keyword(s):  
Distributed Systems ◽  
Markov Process ◽  
Residual Life ◽  
Limit State ◽  
Real Life ◽  
Random Variable ◽  
Operating Pressure ◽  
Remaining Life ◽  
Failure Pressure ◽  
The Moment

Correct assessment of the remaining life of distributed systems such as pipeline systems (PS) with defects plays a crucial role in solving the problem of their integrity. Authors propose a methodology which allows estimating the random residual time (remaining life) of transition of a PS from its current state to a critical or limit state, based on available information on the sizes of the set of growing defects found during an in line inspection (ILI), followed by verification or direct assessment. PS with many actively growing defects is a physical distributed system, which transits from one physical state to another. This transition finally leads to failure of its components, each component being a defect. Such process can be described by a Markov process. The degradation of the PS (measured as monotonous deterioration of its failure pressure Pf (t)) is considered as a non-homogeneous pure death Markov process (NPDMP) of the continuous time and discrete states type. Failure pressure is calculated using one of the internationally recognized pipeline design codes: B13G, B31Gmod, DNV, Battelle and Shell-92. The NPDMP is described by a system of non-homogeneous differential equations, which allows calculating the probability of defects failure pressure being in each of its possible states. On the basis of these probabilities the gamma-percent residual life of defects is calculated. In other words, the moment of time tγ is calculated, which is a random variable, when the failure pressure of pipeline defect Pf (tγ) > Pop, with probability γ, where Pop is the operating pressure. The developed methodology was successfully applied to a real life case, which is presented and discussed.

Effect of Including the Bauschinger Phenomenon in the Formula for Collapse Pressure of Thin-Walled Pipes

2020 ◽  
Author(s):  
Alastair Walker ◽  
Ruud Selker ◽  
Ping Liu ◽  
Erich Jurdik
Keyword(s):  
Hydrostatic Pressure ◽  
Wall Thickness ◽  
Bauschinger Effect ◽  
Pipe Wall ◽  
Large Diameter ◽  
Pipe Material ◽  
Pipe Wall Thickness ◽  
Collapse Pressure ◽  
Compressive Stresses ◽  
Thin Walled

Abstract The method presented by DNVGL in DNVGL-ST-F101 [1], “Submarine pipeline systems”, 2017, for calculating the collapse pressure of submerged pipelines is well-known for design of pipes intended to operate in very deep water. Such pipes are regarded as quite thick-walled with diameter to wall thickness ratio in the range of 15 to 30. There is now substantial experience in the practical manufacture, installation and operation of such pipes. Recently there has been a growing use of large diameter pipelines to transport high volumes of gas over great lengths at moderate water depths. The pipes are considered to be thin-walled with ratios of diameter to wall thickness in the range of 30 to 45. This paper assesses the validity of the DNVGL design method when applied to the design of such thin-walled pipes. A particular aspect of the buckling pressure of large diameter pipes is the effect of the Bauschinger phenomenon. The phenomenon occurs when pipes made using the UOE method are subjected to internal pressure, to provide expansion of the pipe during manufacture, thus reducing the out-of-roundness of the pipe wall, and subsequently subjected to external hydrostatic pressure during pipeline operation. To date the Bauschinger phenomenon has been recognised as resulting in a reduction of the circumferential compressive yield of the pipe material. This reduction is accommodated in the DNVGL design formula. Recent research into material properties has shown that the Bauschinger effect also has the effect of reducing the modulus of steel materials over a range of values of applied circumferential compressive stresses. The paper reviews the basis of the Bauschinger phenomenon and presents results from very detailed accurate testing of UOE pipe material. The tests determine the levels of modulus for pipes subject to circumferential compressive stresses. Although results for compressive stress-strain values have previously been available for pipes subject to high levels of hydrostatic pressure it has been considered that the Bauschinger effect is not generally significant for thick-walled pipes. The tests reported here consider the calculation of material modulus levels for low levels of stress that correspond to the buckling stress of thin-walled pipes. The calculated collapse pressure for such pipes is examined in this paper and compared to corresponding results from the DNVGL design formula to provide guidance on the effect of design levels of pipe wall thickness due to inclusion of the Bauschinger effect. The comparisons are for example pipe wall thickness and material conditions. Conclusions are drawn that including the Bauschinger effect in the calculated pipe wall thickness can have a beneficial effect with regard to pipe manufacturing and installation costs for pipe subjected to mild heat treatment.

scholarly journals Residual Life Prediction of Gas-Engine Turbine Blades Based on Damage Surrogate-Assisted Modeling

2020 ◽  
Vol 10 (23) ◽  
pp. 8541
Author(s):  
Boris Vasilyev ◽  
Sergei Nikolaev ◽  
Mikhail Raevskiy ◽  
Sergei Belov ◽  
Ighor Uzhinsky
Keyword(s):  
Power Plants ◽  
Residual Life ◽  
Turbine Blades ◽  
Predictive Maintenance ◽  
Substantial Part ◽  
Maintenance Planning ◽  
Remaining Life ◽  
Turbine Engine ◽  
Development And Evolution ◽  
Engine Power

Blade damage accounts for a substantial part of all failure events occurring at gas-turbine-engine power plants. Current operation and maintenance (O&M) practices typically use preventive maintenance approaches with fixed intervals, which involve high costs for repair and replacement activities, and substantial revenue losses. The recent development and evolution of condition-monitoring techniques and the fact that an increasing number of turbines in operation are equipped with online monitoring systems offer the decision maker a large amount of information on the blades’ structural health. So, predictive maintenance becomes feasible. It has the potential to predict the blades’ remaining life in order to support O&M decisions for avoiding major failure events. This paper presents a surrogate model and methodology for estimating the remaining life of a turbine blade. The model can be used within a predictive maintenance decision framework to optimize maintenance planning for the blades’ lifetime.

Experimental Characterization of Flow Induced Vibration in Fully Developed Turbulent Pipe Flow

2009 ◽  
Author(s):  
Andrew S. Thompson ◽  
Daniel Maynes ◽  
Thomas Shurtz ◽  
Jonathan D. Blotter
Keyword(s):  
Wall Thickness ◽  
Pipe Wall ◽  
Wall Pressure ◽  
Surface Velocity ◽  
Pipe Diameter ◽  
Pipe Material ◽  
Pipe Surface ◽  
Pipe Wall Thickness ◽  
Wall Pressure Fluctuations ◽  
Pipe Vibration

In this paper we present results of an experimental investigation that characterizes the wall vibration of a pipe with a fully-developed turbulent flow passing through it. Experiments were conducted in a water flow loop where the influences of average fluid speed, pipe diameter, pipe wall thickness, and pipe material on the overall pipe vibration were investigated. The pipe vibration was characterized by accelerometer instruments mounted on the surface of the pipe at multiple locations and the rms of the pipe wall acceleration, velocity, and displacement were measured. Simultaneous measurements of the local temporal fluctuations in the wall pressure were also obtained. Specifically, experiments were conducted in test sections of internal diameters of 3.81 cm – 10.16 cm, pipe wall thickness to diameter ratio ranging from 0.06 – 0.10, and with PVC, aluminum, and stainless steel pipe materials. The experiments were conducted with average fluid speeds ranging from 0 – 11.5 m/s with an accompanying range in the dynamic pressure from 0 – 1 atm. The results show that the rms of the acceleration is proportional to the average fluid speed raised to the 2.12 power. Also, the rms of the pipe surface velocity and the pipe displacement scale with the average fluid speed to the 1.62 and 1.16 powers respectively. Further, the rms of the pipe acceleration and pipe speed increase with increasing pipe diameter, while the pipe modulus of elasticity appears to exert negligible influence on the magnitude of the measured vibrations. The rms of the wall pressure fluctuations scale with the fluid speed raised to the 2.0 power.

scholarly journals Flow-accelerated corrosion rate and residual life time estimation for the components of pipeline systems at nuclear power plants based on control data

2018 ◽  
Vol 4 (1) ◽  
pp. 35-42
Author(s):  
Valery I. Baranenko ◽  
Olga M. Gulina ◽  
Nikolaj L. Salnikov
Keyword(s):  
Wall Thickness ◽  
Power Plants ◽  
Residual Life ◽  
Time Estimation ◽  
Life Time ◽  
Residual Lifetime ◽  
Operational Control ◽  
Continue Development ◽  
Accelerated Corrosion ◽  
Flow Accelerated Corrosion

As of today, large volumes of data related to non-destructive operational control are accumulated on NPPs. For ensuring safe operation of power units, optimization of scope and scheduling operational control it is necessary to continue development of guidance documents, software products, methodological guidance and operational documentation (Baranenko et al. 1998, Gulina et al. 2013, Recommendation (NSAC-202L-R4) 2013). Approaches are examined to assessment of the rate of erosion-corrosion wear (flow-accelerated corrosion - FAC) according to the data of operational control. The present study was performed based on the data of thickness gauging of different elements of pipelines of NPPs with different types of reactor. Further development of ideas exposed in (Baranenko et al. 2016) allowed revealing specific features of ECW processes on straight sections, bends and in the zones adjacent to weld joints of pipelines of NPPs equipped with VVER and RBMK reactors. Presence of the process of deposition of corrosion products on internal surfaces of pipeline walls results in the fact that residual lifetime of elements nominally increases due to deposition. However, real wall thickness under the layer of deposits is unknown just as the initial wall thickness is unknown as well. Investigation implemented in the present study is aimed at the substantiation of the methodology of calculation of FAC rate according to the data of operational control for the purpose of drawing calculation results closer to the reality keeping conservatism. Uniform approach to the assessment of FAC rate in the examined elements of pipelines was developed. Methodologies for evaluation of correction coefficients taking into account dimensional technological tolerances, special features of geometry of the element, as well as effect of deposits on the results of thickness measurements were suggested based on the data of operational control and industry standards. The implemented studies demonstrated efficiency of the developed procedures for pipeline welding zones. Analysis of known and newly developed procedures was performed for bends and ranking of these procedures according to the criterion of “conservatism of evaluation of residual lifetime” was executed. Introduction of correction coefficients allows enhancing conservatism of calculations of lifetime characteristics as compared with calculations performed on the basis of nominal values of thicknesses; the result depends on the type and dimensions of the element, its geometry, as well as on the type of reactor.

A method of technical diagnostics for offshore structures

1994 ◽  
Vol 16 (2) ◽  
pp. 43-48
Author(s):  
Do Son
Keyword(s):  
Diagnostic Method ◽  
Joint Venture ◽  
Oil And Gas ◽  
Residual Life ◽  
Life Time ◽  
Offshore Structures ◽  
Technical Diagnostics ◽  
Offshore Platforms ◽  
South Vietnam ◽  
Local Destruction

This paper describes the results of measurements and analysis of the parameters, characterizing technical state of offshore platforms in Vietnam Sea. Based on decreasing in time material characteristics because of corrosion and local destruction assessment on residual life time of platforms is given and variants for its repair are recommended. The results allowed to confirm advantage of proposed technical diagnostic method in comparison with others and have been used for oil and gas platform of Joint Venture "Vietsovpetro" in South Vietnam.

Development of a mathematical model of the influence of wall thickness on the strain rate when profiling pipes by drawing

2020 ◽  
pp. 49-52
Author(s):  
R.A. Okulov ◽  
N.V. Semenova
Keyword(s):  
Mathematical Model ◽  
Strain Rate ◽  
Wall Thickness ◽  
Pipe Wall ◽  
Strain Intensity ◽  
Thickness Strain ◽  
Pipe Wall Thickness

The change in the intensity of the deformation of the pipe wall during profiling by drawing was studied. The dependence of the strain intensity on the wall thickness of the workpiece is obtained to predict the processing results in the production of shaped pipes with desired properties. Keywords drawing, profile pipe, wall thickness, strain rate. [email protected]

A modified physical model of high-strength water hydraulic artificial muscles considering the effects of geometry and material properties

2021 ◽  
pp. 095440622199907
Author(s):  
Zengmeng Zhang ◽  
Jinkai Che ◽  
Peipei Liu ◽  
Yunrui Jia ◽  
Yongjun Gong
Keyword(s):  
Physical Model ◽  
Relative Error ◽  
Wall Thickness ◽  
Material Properties ◽  
High Strength ◽  
Artificial Muscles ◽  
Operating Pressure ◽  
Rubber Tube ◽  
Contraction Ratio ◽  
Water Hydraulic

Compared with pneumatic artificial muscles (PAMs), water hydraulic artificial muscles (WHAMs) have the advantages of high force/weight ratio, high stiffness, rapid response speed, large operating pressure range, low working noise, etc. Although the physical models of PAMs have been widely studied, the model of WHAMs still need to be researched for the different structure parameters and work conditions between PAMs and WHAMs. Therefore, the geometry and the material properties need to be considered in models, including the wall thickness of rubber tube, the geometry of ends, the elastic force of rubber tube, the elongation of fibers, and the friction among fiber strands. WHAMs with different wall thickness and fiber materials were manufactured, and static characteristic experiments were performed when the actuator is static and fixed on both ends, which reflects the relationship between contraction force and pressure under the different contraction ratio. The deviations between theoretical values and experimental results were analyzed to investigate the effect of each physical factor on the modified physical model accuracy at different operating pressures. The results show the relative error of the modified physical model was 7.1% and the relative error of the ideal model was 17.4%. When contraction ratio is below 10% and operating pressure is 4 MPa, the wall thickness of rubber tube was the strongest factor on the accuracy of modified model. When the WHAM contraction ratio from 3% to 20%, the relative error between the modified physical model and the experimental data was within ±10%. Considering the various physical factors, the accuracy of the modified physical model of WHAM is improved, which lays a foundation of non-linear control of the high-strength, tightly fiber-braided and thick-walled WHAMs.

Designing CO2 Transmission Pipelines Without Crack Arrestors

2010 ◽  
Author(s):  
Graeme G. King ◽  
Satish Kumar
Keyword(s):  
Wall Thickness ◽  
Carbon Capture ◽  
Power Plants ◽  
Oil And Gas ◽  
Cost Optimization ◽  
Operating Conditions ◽  
Operating Pressure ◽  
Design Work ◽  
Industrial Facilities ◽  
Pipeline Network

Masdar is developing several carbon capture projects from power plants, smelters, steel works, industrial facilities and oil and gas processing plants in Abu Dhabi in a phased series of projects. Captured CO2 will be transported in a new national CO2 pipeline network with a nominal capacity of 20×106 T/y to oil reservoirs where it will be injected for reservoir management and sequestration. Design of the pipeline network considered three primary factors in the selection of wall thickness and toughness, (a) steady and transient operating conditions, (b) prevention of longitudinal ductile fractures and (c) optimization of total project owning and operating costs. The paper explains how the three factors affect wall thickness and toughness. It sets out code requirements that must be satisfied when choosing wall thickness and gives details of how to calculate toughness to prevent propagation of long ductile fracture in CO2 pipelines. It then uses cost optimization to resolve contention between the different requirements and arrive at a safe and economical pipeline design. The design work selected a design pressure of 24.5 MPa, well above the critical point for CO2 and much higher than is normally seen in conventional oil and gas pipelines. Despite its high operating pressure, the proposed network will be one of the safest pipeline systems in the world today.

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