Pipe Rupture Research Articles

Research on Pipeline Stress Detection Method Based on Double Magnetic Coupling Technology.

Oil and gas pipelines are subject to soil corrosion and medium pressure factors, resulting in stress concentration and pipe rupture and explosion. Non-destructive testing technology can identify the stress concentration and defect corrosion area of the pipeline to ensure the safety of pipeline transportation. In view of the problem that the traditional pipeline inspection cannot identify the stress signal at the defect, this paper proposes a detection method using strong and weak magnetic coupling technology. Based on the traditional J-A (Jiles-Atherton) model, the pinning coefficient is optimized and the stress demagnetization factor is added to establish the defect of the ferromagnetic material. The force-magnetic relationship optimization model is used to calculate the best detection magnetic field strength. The force-magnetic coupling simulation of Q235 steel material is carried out by ANSYS 2019 R1 software based on the improved J-A force-magnetic model. The results show that the effect of the stress on the pipe on the magnetic induction increases first and then decreases with the increase in the excitation magnetic field strength, and the magnetic signal has the maximum proportion of the stress signal during the excitation process; the magnetic induction at the pipe defect increases linearly with the increase in the stress trend. Through the strong and weak magnetic scanning detection of cracked pipeline materials, the correctness of the theoretical analysis and the validity of the engineering application of the strong and weak magnetic detection method are verified.

Failure Analysis of Bypass Rupture of Flowmeter in Steam Pipeline

Abstract A petrochemical company’s pipeline ruptured in the flowmeter bypass of the main steam pipeline during a steam blowdown before commissioning, resulting in material failure and inoperability. The cause of the pipe rupture needed to be detected experimentally. To study the failure in the steam pipeline of a flowmeter of bypass rupture, visual inspection, mechanical properties testing, chemical composition analysis, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Mechanical property. The experiments confirmed the reason for the bypass rupture of the 15CrMoG steam pipeline: improper heat treatment transforms the material’s structure, and the pearlite spheroidization (PC) leads to the deterioration of the material’s mechanical properties. The main manifestations are as follows: the grains in the superheated zone of the welding exhibit a coarse morphology, and a distinctive superheated Widmanstatten structure is formed due to rapid cooling, resulting in a significant reduction in material plasticity and impact toughness. High-temperature oxidation occurs, accompanied by localized enrichment of Cr-element in certain areas, while other regions experience Cr depletion, resulting in the deterioration of material properties.

Design and Development of a Pipeline Maintenance System for Pipe Surge and Water Hammer Equipment Based on Siemens S7-1200 PLC

Fluids play a crucial role in the lives of living beings, as they are substances that can flow. In a piping system, a common issue is water pressure fluctuation caused by sudden closures of water flow (Idul, 2021). Pipe surge and water hammer equipment are utilized to demonstrate the transient pressure effect resulting from abrupt changes in flow velocity within pipes (David, 1981). Water hammer can lead to pressure surges throughout the piping system, potentially causing failures that result in leaks in pipes, valves, pipe joints, and even pumps if the pressure exceeds the pipe's capacity (Prasetya, 2016). The likelihood of pipe ruptures or leaks at joints increases significantly. Additionally, equipment movement, slope, and precision of pipe installation can also contribute to leaks during water hammer events. This research aims to develop a pipe leakage monitoring system to address the impact of water hammer. The system will be installed in areas deemed susceptible to this phenomenon, along with a periodic maintenance indicator system to minimize the impact of pipe leaks. The research will also investigate the potential risks associated with varying fluid flow rates in the piping system. The monitoring, indicator, and sensor systems will be integrated into a PLC and HMI system for data processing.

Determining effective sampling frequencies for transient pressure events in water distribution systems optimal sampling for WDS transients

This study introduces a novel methodology for determining the optimal frequency for pressure data acquisition in water distribution systems (WDSs) in response to transient-flow events such as pipe ruptures. By leveraging actual design and operational data, we simulated potential rupture scenarios and their resultant pressure wave patterns through transient-flow analysis. Harmonic series modeling was used to identify significant periods that closely replicate the observed pressure-wave time series. This allowed the derivation of recommended data acquisition intervals tailored to each monitoring site within the network. The proposed approach facilitates comprehensive analysis of all possible hydraulic shock scenarios, which can provide insights into both the existing monitoring infrastructure and strategic planning in the design phase of the WDS. Although the methodology focuses on rupture events, its application can extend to various water-quality indicators and flow rates, albeit with consideration of their typically static behavior.

Effects of Internal Pressure on Urban Water Supply Pipeline Leakage-Induced Soil Subsidence Mechanisms

After the rupture of pressurized water supply pipes in urban underground areas, seepage-induced ground subsidence becomes a severe geological hazard. Understanding the permeation and diffusion patterns of water in soil is crucial for deciphering the mechanisms underlying soil settlement and damage. Notably, the pressure within water supply pipes significantly influences the settlement and damage of the soil. Therefore, this study simulated experiments on soil settlement and damage caused by water seepage from a preexisting damaged pipeline under various internal pipe pressure conditions using an indoor model apparatus. The results indicate that the internal pressure of the pipe significantly influences the settlement of the soil. High-pressure seepage causes noticeable erosion in the soil, forming cavities within it. In contrast, low-pressure seepage results in water diffusing in an ellipsoidal pattern, leading to the formation of circular surface cracks. The degree of surface settlement increases with higher pipe pressure. The onset of subsidence at a specific point on the ground is not directly related to whether the moistening front within the soil has reached that point horizontally. Instead, it is associated with the moisture content below the subsidence point within the soil. The research results further illustrate the water diffusion and moisture content increase processes after water seepage from pipes with different pressures, revealing the influence of pipe pressure on the degree and form of soil settlement damage and clarifying the relationship between water diffusion and settlement in the soil.

Анализ аварийности канализационных трубопроводов внутриконтинентального города Северного Китая

Purpose: to analyze the causes of the destruction of drainage pipelines that occurred in an inland city in northern China from 2017 to 2022 and make proposals to reduce the number of emergency situations. Methods: describe the causes of destruction of drainage pipelines and conduct a comparative analysis. Results: as a result of the study, it was found that the pipelines of the inland city in northern China sewerage network are quite old and have a high accident rate. The main causes of emergency situations are corrosion processes, pipe ruptures, and heavy precipitation. The work proposes measures to improve the reliability of the operation of such pipelines, including monitoring and monitoring the condition of pipelines with the subsequent assignment of various types of restoration work. Practical significance: the results of the work are recommended to be taken into account when solving problems of destruction of drainage pipelines in other regions of China.

Design and optimization analysis of a new double-layer tube type heat exchanger for lead-bismuth reactors

Double-layer heat tubes have been designed to effectively reduce the occurrence of heat pipe rupture accidents. However, inter-tube thermal contact resistance can decrease heat transfer efficiency, thus hampering the heat dissipation in the primary loop system of lead-bismuth reactors. Therefore, optimizing the design of double-layer heat tubes is necessary. This work focuses on the double-layer heat exchanger of a lead-bismuth reactor and utilizes gallium-based graphene nanofluids as a thermal interface material to fill the gap between the heat tubes. Furthermore, the impact of the length, wall thickness, outer diameter, and spacing of heat tubes on the heat transfer performance of the double-layer heat exchanger with and without the nanofluids has been analyzed. The study aims to optimize the JF factor and cost-effectiveness ratio (CER). Genetic algorithms are employed to optimize and evaluate the heat transfer performance of the main heat exchanger based on the four aforementioned parameters. Consequently, a new design scheme is obtained for the double-layer heat exchanger, which increases the optimized overall heat transfer coefficient of the main heat exchanger by 5.79%, pressure drop in the primary loop by 2.32%, JF factor by 5%, and CER by 24.62%. These results demonstrate that the gallium-based graphene nanofluids can effectively enhance the heat transfer performance of the double-layer heat exchanger while reducing the likelihood of steam generator tube rupture accidents.

Stochastic analysis of structural reliability of complex engineering systems

Purpose: The assessment of risks and prediction of reliability of complex engineering systems, in particular onshore gas pipelines subjected to external corrosion. Two methods are proposed using the structural reliability analysis.Methodology: Two strategies are considered for inspection and maintenance service of hazardous production facilities.Research findings: The model of structural reliability is proposed to estimate the metal rupture from external corrosion of the pipe section. Models are presented for its mechanical failure with respect to stochastic processes of loads and resistance.Value: The inhomogeneous Poisson point process is used to simulate the formation of new defects, and the Poisson distribution is used to simulate their growth. The first method focuses on the analysis of external corrosion of gas pipelines with metal loss and predicts rupture at a reference pipe segment, constructed with respect to average pipe rupture characteristics from the PHMSA database. The second model predicts reliability for untreated sections subject to external corrosion with metal loss.

Research on the characteristics of weak magnetic internal detection signals for critical damage in pipeline stress based on density functional theory

Pipeline stress-induced critical damage is a primary cause of sudden pipe ruptures. To investigate the characteristics of weak magnetic internal detection signals related to critical damage in pipeline stress, a magneto-mechanical model was developed based on density functional theory. The model could assess the corresponding relationships among the generalized stacking fault energy (GSFE), critical resolved shear stress (CRSS), atomic magnetic moment, and magnetic signals during the critical damage process of the pipeline. The analysis included examining the influential patterns of different stress directions and materials on the magnetic signals associated with critical damage, followed by the systematic experimental verification.The research results indicated that when the crystal dislocation stress exceeded the CRSS, weak magnetic signals could effectively characterize the critical damage induced by stress, accompanying by a sharp variation in magnetic signals observed during critical damage occurrence. Different stress directions lead to varying energy barriers that must be overcome for critical damage, resulting in distinct magnetic signal features. In the {112} plane, the CRSS increased by 11.07 % compared with {11¯0} plane, and the axial magnetic signal during critical damage was elevated by 1.47 % compared with {11¯0} plane. Variances in magnetic signals for critical damage were assessed for steel pipes of different materials due to differences in processing and composition. Under identical conditions, the magnetic signal difference for critical damage in X80 steel plates was 39 % higher than that in X70 steel plates. Additionally, the magnetic signal difference for critical damage in the circumferential weld of X80 was 53 % higher than that in X80. The findings provided a theoretical basis for monitoring and early warning of critical damage states in pipelines.

STUDY OF THE DYNAMICS OF ASSOCIATED DRILL STRINGS INTERACTING WITH THE WELL WALL

The depth of exploration and production wells during the development of oil and gas fields can exceed 5-10 km, and the insufficient strength and reliability of the drill string often limits the possibility of further increasing labour productivity. In addition, accidents at wells lead to significant material costs. Therefore, the design and operation of drill strings, as well as the implementation of work to eliminate complications during drilling, should be carried out on the basis of a science-based approach, taking into account the latest advances in the field of drill string dynamics and technologies related to work to eliminate stuck problems. Unsteady vibrations of inhomogeneous distributed systems is a very complex problem in the mechanics of a deformable solid and the theory of vibrations. In connection with the rapid development of the extractive industries, solving this problem is of particular importance. This is due to ensuring the strength of drill string structures with increasing power and speed of drilling units and mechanisms. The study of the problem revealed a number of little-studied problems, which include issues of nonlinear interaction of the column with the surrounding soil, accompanied by various types of complications (sticking, pipe ruptures, etc.), wave and oscillatory processes in the elements of the drilling dynamic system (DDS), finding the boundaries of the interaction areas of the column with the walls of the well using low-cost techniques. The purpose of the work is theoretical research of wave and oscillatory processes in the pipes of the drilling assembly and the dynamics of associated drill strings interacting with the well wall. In this work, a homogeneous rod was used as a drill string model. The drill string consists of a drill pipe string (DPC) and a bottom drill string assembly (BDSA), which includes a bit, a downhole motor, wellbore forming elements: calibrators, centralizers, sections of drill collars (DC), the main purpose of which is to creating an axial load on the bit. The DPC consists of sections of drill pipes that are identical in their characteristics (type, outer diameter, wall thickness, joints used, etc.). Therefore, in general, the drill string is a heterogeneous structure.

Avoiding water hammer and other hydraulic transients

AbstractWater hammer may occur upon rapidly closing a water pipe valve. Oscillating pressure waves generated in the system may cause significant equipment damage, including joint leaks and even pipe rupture. Similar phenomena can occur when starting and stopping pumps. As various situations can cause potentially damaging pressure waves, water hammer and related phenomena are grouped as “hydraulic transients.” The phenomena are not limited to water pipes and may occur in any liquid, including condensed gases such as chlorine, ammonia, and liquefied natural gas (LNG). Hydraulic transients deserve more coverage in college courses and textbooks on process safety, while at an industrial level, the topic should be considered in design and hazard reviews. This article provides a brief introduction to the topic with a focus on mitigation methods. Available options should be evaluated during the design process rather than applied retroactively after a problem becomes evident.

Reliability Analysis of Pipe Wall Thinning based on Quantification of Ultrasonic Testing

Piping in nuclear power plants is subject to corrosion and erosion caused by the interaction with fluids it carries. In order to prevent accidents such as pipe rupture, it is necessary to non-destructively inspect the thickness of the pipe wall and predict the remaining pipe life. In contrast, signals obtained by non-destructive inspection are affected by various uncontrollable and unknown factors, which will result in uncertainty in evaluating pipe wall thickness. Ignoring the uncertainty would lead to a large error in the pipe reliability assessment. Therefore, it is important to develop a reasonable pipe wall thinning management that can takes the uncertainty of non-destructive testing into consideration. Based on this background, this study aimed to develop a piping wall thinning prediction model that accounts for the uncertainty in evaluating pipe wall thickness and to evaluate its applicability to ultrasonic testing. At first, ultrasonic tests were performed to measure the thickness of specimens simulating flow accelerated corrosion. The results of the measurements were statistically analysed to obtain a mathematical model correlating the evaluated and true thickness. A numerical model to predict the reduction of wall thinning with its uncertainty is developed. Compared to the conventional method, the proposed method is able to predict wall thickness with high accuracy.

The Influence of Storage Tank Volume on the Nighttime Heat Dissipation and Freezing Process of All-Glass Vacuum Tube Solar Water Heaters

The issue of freezing often occurs when using all-glass vacuum tube solar water heaters during cold winter seasons, leading to problems such as pipe ruptures and tank leakage. In order to further study the nocturnal heat dissipation and freezing characteristics of these heaters, a three-dimensional transient numerical model of their nocturnal heat dissipation was established. The model simulated the nocturnal heat dissipation process, and experimental validations were conducted through nocturnal temperature drops of the collector and temperature drops of individual tubes without a storage tank. Experimental and simulation results revealed that in clear weather conditions during cold winters in Luoyang, the all-glass vacuum tube solar water heaters experienced freezing issues during the night, with freezing predominantly starting from the bottom surface of the vacuum tubes. The frozen length along the tube wall and the thickness of ice at the bottom section reached up to 1180 mm and 5 mm, respectively. In the absence of a storage tank, the freezing situation was severe, with approximately 4/5 of the individual tubes completely frozen. Under specified operating conditions, different storage tank volumes exhibited varying degrees of freezing in the all-glass vacuum tube solar water heaters. When the volume was increased to 15 L, the temperature drop in the storage tank and the vacuum tubes decreased by 12.1% and 7.6%, respectively. Larger storage tank volumes resulted in reduced freezing risks in all-glass vacuum tube solar collectors. This study provides valuable guidance for the design and application of solar collectors and serves as a reference for the development and application of solar energy utilization technologies.

Experiments and evaluation on residual strength of X52 steel pipe with various internal defects

The strength of the natural gas transmission pipe is reduced due to sag deformation and corrosion defects. However, there are rare experiment data to quantitatively describe the effect of the defect’s size and position on the pipe strength. This paper designed seven groups of steel pipes with various defects to perform the hydrostatic bursting experiments, and to research the effects of the defects on the strength of the steel pipe. The experimental pipe sample is selected as the X52 material. Three types of defects were set up: concave and corrosion combinational defects, one corrosion defect, and two corrosion defects. The pipe rupture size, the strain around defects, and pipe perimeters before and after experiments are measured, finally yielding the strain-pressure curve of each steel pipe. Comparisons of experimental results show that the defect depth is the dominant factor affecting the pipe strength. Moreover, results show that the DNV-RP-F101 code tends to yield less distance beyond which two defects will not affect each other. The ASME B31G code also tends to give a lower residual strength of the pipe. However, in comparison with the PCORRC criterion, the ASME B31G formula has higher accuracy for X52 pipes. The average relative deviation between the experimental and calculated corroded pipe strength is 14.87%.

DEMO Divertor Cassette and Plasma facing Unit in Vessel Loss-of-Coolant Accident

As part of the pre-conceptual design activities for the European DEMOnstration plant, a carefully selected set of safety analyses have been performed to assess plant integrated performance and the capability to achieve expected targets while keeping it in a safe operation domain. The DEMO divertor is the in-vessel component in charge of exhausting the major part of the plasma ions’ thermal power in a region far from the plasma core to control plasma pollution. The divertor system accomplishes this goal by means of assemblies of cassette and target plasma facing units modules, respectively cooled with two independentheat-transfer systems. A deterministic assessment of a divertor in-vessel Loss-of-Coolant Accident is here considered. Both Design Basis Accident case simulating the rupture of an in-vessel pipe for the divertor cassette cooling loop, and a Design Extension Conditions accident case considering the additional rupture of an independent divertor target cooling loop are assessed. The plant response to such accidents is investigated, a comparison of the transient evolution in the two cases is provided, and design robustness with respect to safety objectives is discussed.

Propagation and intensity of blast wave from hydrogen pipe rupture due to internal detonation

The coupled fluid-structure-rupture model was developed to study the propagation and intensity of blast wave from hydrogen pipe rupture due to internal detonation. The dynamic rupture of pipe and propagation of blast wave were well coupled together in every timestep during the simulation. The numerical model was validated with experiments in terms of both typical rupture profiles and blast overpressures. Results reveal that crack branching of pipe can dramatically increase the rupture opening rate which controls the intensity and shape of the resultant blast wave. Due to the process of crack initiation and extension, the blast wave out of the pipe first forms and then is strengthened by the subsequent compression waves. This makes the maximum peak overpressure appears at a certain standoff distance above the rupture. Despite consuming some percentages of energy, the dynamic rupture of pipe generally presents positive effects (up to 2–3 times) on the blast wave intensity along the jetting direction due to the convergence effect of rupture opening on the release of internal high-pressure gas. Finally, through defining normalized overpressure and impulse based on the same hydrogen detonation in open spaces, the quantitative influences of pipe rupture on the blast wave intensity in cases of different detonation pressures and standoff distances are clarified.

Mechanical property degradation of X80 pipeline steel due to microbiologically influenced corrosion caused by Desulfovibrio vulgaris.

Apart from pinhole leaks, MIC (microbiologically influenced corrosion) can also cause catastrophic failures such as pipe ruptures and support beam collapses due to mechanical property degradation or stress corrosion cracking. In this work, X80 pipeline steel dogbone coupons and square coupons were immersed in 150ml broths containing Desulfovibrio vulgaris, a common corrosive sulfate reducing bacterium (SRB), for up to 14days. The headspace volumes in the anaerobic bottles were increased from 150ml to 200ml and 300ml to increase MIC severity. After 14days of SRB incubation in ATCC 1249 culture medium with X80 coupons at 37°C, the sessile cell counts were 6.5 × 107 cells cm-2 for 150ml, 2.3 × 108 cells cm-2 for 200ml and 1.4 × 109 cells cm-2 for 300ml headspace volumes, respectively owing to reduced H2S cytotoxicity in the broth with a larger headspace because it allowed more biogenic H2S to escape from the broth. Weight losses were 1.7mg cm-2, 1.9mg cm-2 and 2.3mg cm-2 for 150ml, 200ml and 300ml headspace volumes, respectively. The corresponding pit depths were 2.6μm, 4.2μm and 6.2μm for 150ml, 200ml and 300ml headspace volumes, respectively. Electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and potentiodynamic polarization results corroborated the increasing weight loss and pitting data trends as a result of increased headspace. Tensile testing of dogbone coupons after the 14-day SRB immersion test indicated that more severe MIC pitting led to a higher ultimate strain loss by up to 23% (300ml headspace) compared to the abiotic control, while the ultimate strength losses for all headspace volumes were quite small (3% and lower).

A dynamic fracture finite element model of the buried gas transmission pipeline combining soil constraints and gas decompression

A long-distance natural gas transmission pipeline is the primary solution for natural gas resource distribution. In fact, the longitudinal crack propagation of gas transmission pipelines has always been a concern of the natural gas industry. Because it will cause disastrous accidents once the ductile crack in the pipeline propagates rapidly. Most natural gas transmission pipelines are buried underground to improve the safety of pipeline operation as the backfill soil can absorb energy during the fracture process and restrain the displacements of the flaps. Fracture control is a fundamental requirement for the safe operation of underground pipelines. In this study, the dynamic fracture finite element model of the buried gas pipeline is developed to simulate the actual fracture process instead of the costly full-scale burst experiments. The finite element model incorporates different external soil constraints and internal gas decompression behaviors during pipe rupture in which soil constraints are represented by discrete soil springs, and a user-defined subroutine realizes the gas decompression behavior. The explicit dynamic analysis is employed to simulate the high-speed dynamic fracture process of the pipeline, and the crack propagation is simulated by using the cohesive zone model. Finally, the crack propagation velocity is calculated by this model, and the influence of different internal pressures on the fracture velocity is studied; the crack tip opening angle (CTOA) is predicted, and the effect of soil spring stiffness on CTOA is evaluated.

Online autonomous calibration of digital twins using machine learning with application to nuclear power plants

As a near-zero carbon emission energy source, nuclear energy plays an important role in the current world energy decarbonization scenario. Digital twin is a key technology for the continued development of nuclear energy applications. The digital twin requires real-time, high-precision simulations that are beyond the capabilities of current nuclear energy system simulation programs. Therefore, this study proposes an autonomous calibration method for the digital twin of nuclear power plants to compensate for the error in the results of the low accuracy digital twin that can run quickly to obtain higher accuracy results to meet both high accuracy and real-time requirements. The proposed method consists of offline and online stages. In the offline stage, digital twin simulations are first performed. The simulated data and corresponding measurements data (or real data) are used to build an error database, which will be used for the next step of data-driven model training. To reduce the complexity of calibration model, the error database samples are then grouped by clustering. Data-driven calibration models are built on each group based on the simulated data and errors. In the online stage, the digital twin runs in parallel with the nuclear power plant and receives real-time data. The calibration model is continuously updated using dynamic error database. The feasibility of the new proposed method has been demonstrated on measured data from the PKLIII B3.1 steam generator pipe rupture (SGTR) experiment. The results showed that the physical quantities such as pressure, temperature and mass flow rate were well calibrated during the 1000 s of parallel running. The R2 of all physical quantities including temperature, flow rate, and pressure are above 0.99.

RISK ANALYSIS TECHNIQUES OF OIL AND GAS PIPELINE

The safety of pipelines that transport energy has become an important and controversial issue with the general public. The main hazard for safe transportation of substances is a pipeline failure taken as a loss of its tightness and release of the transported medium to the environment. To perform reliability analysis and estimation of accident risk level, Fault Tree Analysis (FTA) and Event Tree Analysis (ETA) are two graphical techniques used to perform a risk analysis, where FTA represents causes and their probabilities of failures, and ETA represents consequences of a failure event. Failure of oil transmission pipelines was analyzed by fault tree analysis in this project, and the probability of internal corrosion, one of the root causes, has been evaluated by applying the physical reliability model. According to failure modes of pipeline, leakage and rupture, a fault tree of the pipeline was constructed. Minimal cut sets of the fault tree have been shown, and the failure probability of a top event and the important analyses of basic events were evaluated by quantitative analysis. In conventional fault tree analysis, probabilities of the basic events were treated as precise values. At last, the probability of different accident scenarios that may result from failed oil pipeline due to pipe rupture has been estimated.