Gas Pipeline Design Research Articles

Assessment of hydrogen-induced material degradation using electromagnetic testing technology

The production, transport and use of green hydrogen are key issues for the efficient use of renewable energies. Hydrogen is able to compensate for both temporal and spatial fluctuations that naturally occur in the production and consumption of renewable energies, regardless of weather conditions, and thus can act as an efficient energy storage medium. The use of existing gas pipelines in a dynamically operated pipeline network offers particular potential for the transport of green hydrogen with regard to sustainability, resource conservation and economic efficiency. In this context, dynamic means that pressure fluctuations are permissible to a certain extent in the operation of gas pipelines. However, a hydrogen-induced degradation of the mechanical material properties can lead to brittle fracture and manifest itself in sudden material failure. Such failure must be excluded in safetyrelevant infrastructures. Hence, it would be beneficial to detect fatigued or degraded areas in the material at an early stage, especially in the context of possible increased crack growth rates associated with hydrogen embrittlement. In addition to fatigue data, which are crucial in the calculation and design of gas pipelines, non-destructive inspections are particularly important in subsequent operation to monitor the current condition of the pipelines. Non-destructive testing focuses primarily on defects such as cracks that have already developed or on visible corrosion attack. The fatigue condition, i.e., the probability of crack initiation and crack propagation is hard to evaluate. However, this can be addressed by an electromagnetic test method capable of evaluating the current state of the material. In the presented paper, an electromagnetic test method is presented, which is able to detect and evaluate hydrogen-induced material degradation. In subsequent stages, such a method can then be used as an electromagnetic monitoring system in fatigue tests, thus providing new potential for condition assessment.

Analysis of natural and climatic processes in mountainous areas affecting the design of gas pipelines

Analysis of natural and climatic processes in mountainous areas affecting the design of gas pipelines

Incorporating seismic risk assessment into the determination of the optimal route for gas pipelines

ABSTRACT Earthquake-induced damage to gas pipelines can have severe economic, social, and environmental consequences. To mitigate these risks, one effective way is to carefully design the route of gas pipelines, considering the seismic hazard of the region. This paper proposes a methodology that incorporates seismic risk assessment into the process of designing gas pipeline routes. Conventional gas pipeline design methods consider only minimum distances from faults and fail to account for seismic potential. The methodology is applied to three gas pipeline routing problems in the high seismic region of southern Iran. Seismic risk is evaluated using the HAZUS method, and routing is performed through a GIS-based approach. Results are compared with conventional approaches in terms of length, seismic risks, and damage costs, showing the proposed method’s effectiveness in reducing immediate consequences like leaks and breaks in gas transportation. The proposed method reduces seismic damage by 3 to 68% for routing problems.

Characteristics of Coal Dust Deposition in Boiler Tail Gas Pipelines

Coal dust deposition in boiler tail gas pipelines can significantly affect boilers’ thermal and energy efficiency. This study investigates the deposition characteristics of coal dust particles in boiler tail gas tubes in variable cross-section tubes. Numerical simulations were performed using the Reynolds Stress Model and the Discrete Particle Model. User-defined functions coding is used to construct the particle deposition model in the particle deposition model. The study analyses the distribution of turbulent kinetic energy locations in the gradient tube, compares the distribution of particle deposition on its wall, and concludes that the deposition distribution of coal dust particles in the gradient tube is slightly different for different particle sizes. Smaller particles have a higher deposition efficiency in equal cross-section pipes than larger particles. Particle size also has a significant effect on pipe taper and expansion. The results of this study can provide theoretical guidance for optimising the design of boiler tail gas pipelines, improving energy efficiency, and reducing environmental pollution.

Characteristics of Coal Dust Deposition in Boiler Tail Gas Pipelines

Coal dust deposition in boiler tail gas pipelines can significantly affect boilers’ thermal and energy efficiency. This study investigates the deposition characteristics of coal dust particles in boiler tail gas tubes in variable cross-section tubes. Numerical simulations were performed using the Reynolds Stress Model and the Discrete Particle Model. User-defined functions coding is used to construct the particle deposition model in the particle deposition model. The study analyses the distribution of turbulent kinetic energy locations in the gradient tube, compares the distribution of particle deposition on its wall, and concludes that the deposition distribution of coal dust particles in the gradient tube is slightly different for different particle sizes. Smaller particles have a higher deposition efficiency in equal cross-section pipes than larger particles. Particle size also has a significant effect on pipe taper and expansion. The results of this study can provide theoretical guidance for optimising the design of boiler tail gas pipelines, improving energy efficiency, and reducing environmental pollution.

Development of the method for determining the deformation parameters and remidal stresses of metal in the manufacture of straight-seached pipes of large diameter using expansion

Since 2020, in Ukraine, LLC NVP «UKRTRUBOIZOL» began to operate a technological line for the production of large-diameter pipes (TVD) for main oil and gas pipelines with a hydromechanical expander. From 2023, interstate GOST 20295-85 and GOST 10706-76 ceased to be valid in Ukraine. Formulation of the problem. Ukrainian standards are needed. It is necessary to determine the rational values of the deformations and the effectiveness of the expansion to reduce the residual stresses in the metal of the pipes. Goal. Development of Ukrainian standards for TVD production and determination of the effect of expansion on residual stresses. Method. The method of cutting rings was used. The results. Developed and implemented with the participation of author: DSTU 9219:2023; DSTU 9218:2023 and TU 24.2–05757883–095:2022. Pipes with a diameter of 630 mm, with a wall of 8 mm, made of S335 steel and hot-rolled rolled sheet were studied. The opening between the longitudinal edges of the pipe blank after bending was 70-80 mm. For the ring after welding, the opening was 180 mm and for the rings expanded by 0.8%, 1.2% and 0.4% -58-53 mm. This indicates that the residual expansion stresses were much smaller than in the pipe after welding the seam, and the amount of expansion change from 0.4% to 1.2% does not affect the residual stresses. Scientific novelty. For the first time, for the JCOE technology of production of TVD from rolled hot-rolled sheet, the influence of expansion on residual stresses was determined experimentally. It was shown that the opening of the rings during expansion is significantly reduced. For the first time, the influence of the amount of expansion on the reduction of residual stresses was determined for the JCOE technology of TVD production. It is shown that deformations of 0.4-1.2% give the same opening of the rings after expansion. Practical significance. The obtained results can be useful for the personnel of steel welded TVD production enterprises and project organizations sn the design of oil and gas pipelines

Algorithm for Calculating Reliability of Single Linear Section of Steel Underground Pipeline

One of the most widespread technical systems in the world is underground steel pipeline communications (heat pipelines, main and distribution oil and gas pipelines, etc.). Accordingly, reliability assessment of such technical systems and their components is of great theoretical and practical interest. At the modern level of development, reliability calculation has become a mandatory stage in the design and diagnostics (during operation) of any technical systems in ge-neral, and in particular pipeline systems. A reliable calculation, either explicitly or implicitly, is always based on the model of the object being calculated. It is the adequacy of the model to the real physical relations and processes inside the technical object that determines the accuracy and practical value of calculation methods. It is proposed to consider a single linear section of an underground steel pipeline as a complex technical system of unequal elements from the point of view of reliability – the main element (steel pipe) and auxiliary protective elements combined into subsystems (blocks). The algorithm for calculating the reliability of the object is based on the method of block diagrams, taking into account the influence of the aftereffect of the failure of an auxiliary element (elements) on the reliability parameters of the main element, which more adequately reflects the specific features of the design and operation of steel pipelines compared with the applied static models. The variants of structural design of a steel underground gas pipeline with a protective insulation coating and with complex corrosion protection (insulation and electrochemical protection) are considered, for which refined formulas are obtained for calculating the main reliability (failure-free) indicators.

Laboratory investigation on the pipeline-soil interaction under different freezing conditions

Designing buried natural gas pipelines in frozen ground requires a comprehensive evaluation of the interaction between pipelines and soil, considering the effects of temperature and water supply conditions. One-dimensional freezing experiments are conducted to investigate soil frost heave characteristics and pipelines strain at three cooling modes, namely, constant cooling mode, linear cooling mode, and stepwise cooling mode. The impacts of cooling modes and water supply conditions on freezing rate, frost heave, and pipeline strain are analyzed. The results indicate that the largest soil frost heave occurs at an ambient temperature of −10 °C, irrespective of water supply presence. Both the linear and stepwise cooling modes enhance the flatness of the overlying soil, as opposed to the constant cooling mode. The stepwise cooling mode reduces freezing rate, yet leads to a higher tensile strain in the pipeline structure compared to the linear cooling mode. The relative incremental strain is the greatest when the freezing depth ranges from one to two times the diameter of pipelines. The test results could provide a reference for the design of buried natural gas pipelines in cold regions.

Analysis of the mechanical characteristics and plasticity-hazardous zones development of natural gas pipeline under overload

The problem of natural gas pipeline overload failure is of great significance, and the development law of critical mechanical properties of pipelines is of great importance to the safety design of natural gas pipelines. This study establishes a three-dimensional finite element computational model of the pipeline that integrates the changes in axial and circumferential mechanical characteristics, and uses the yield strength, safety factor and ellipticity indexes as criteria to dimensionless the axial depth and circumferential angle of the plastic zone to explore the characteristics of the plastic damage stage of the pipeline. By solving the plastic hazardous zones based on the safety factor, the applicability of the dimensionless parameters is extended to investigate the development laws of the hazardous zones and the correlation mechanism between failure criteria and hazardous zones. The results show that as the ground load increases, the pipeline deformation gradually develops into the plastic stage (P = 16 MPa) and then goes through three deformation stages. With the increase of safety factor, the change trend of the proportion of stage I in the whole loading process decreases to 4 %, the change trend of the proportion of stage III increases significantly to 52 %, while the proportion of stage II shows a change trend of decreasing and then increasing, the proportion of this stage ranges from 30 % to 38 %. Based on the law of variation of axial ellipticity of pipeline section, a high-risk section of pipeline was identified in the range of 0–2 m from the point of maximum local compression strain. The results of the study can serve as a basis for accurate evaluation of the safety status of natural gas pipelines under overload.

Research on Effect Factors of Mechanical Response of Polyethylene Gas Pipeline in Karst Area Based on Element Birth and Death Technique

Abstract Buried gas pipelines in karst area are inevitably affected by the geotechnical activities, which is difficult to resist the permanent ground displacement caused by soil dislocation and surface damage. In this paper, abaqus finite element software has been used to establish a pipe-soil nonlinear coupling model based on element birth and death technique. The influence rules of various sensitive factors on the stress response of gas pipelines are studied. The work presented in this paper can provide a reference for the design and safety of polyethylene gas pipeline crossing the karst area.

Experimental Study on Mechanical Response of Oil and Gas Pipelines under Ground Subsidence

At present, accidents of buried pipelines caused by localized ground subsidence are reported frequently. Understanding the mechanical response of pipe soil during subsidence is of great significance to the safe operation of buried pipelines. This paper studies the stress state of buried oil and gas pipelines and their surrounding soil through a series of large-scale model tests in the process of localized ground subsidence. The experiment results show that during the process of subsidence, the axial and hoop strain of the pipeline increases with the expansion of the subsidence area and the subsidence amount. The subsidence amount has a relatively greater influence, and the distribution characteristics of the pipeline strain present obvious regional characteristics. The earth pressure around the pipe shows different changes in the process of subsidence, among which the earth pressure on the upper part of the pipe is the main one. The research results can provide a certain reference for the design and calculation of oil and gas pipelines under foundation settlement.

Technology of engineering and geodetic survey with aerial photography for gas pipeline design

The article considers the modern method of solving large number of geodetic problems in a short period of time without loss of accuracy and quality of materials obtained from a complex engineering and geodetic survey using aerial photography.

An enhanced network design of natural gas pipelines by controlling gas flow: considering supply reliability and operation efficiency

An enhanced network design of natural gas pipelines by controlling gas flow: considering supply reliability and operation efficiency

Thermo-mechanical Behaviour of Soft Clay between Operation and Shutdown of Submarine Hot Oil Pipeline

The interaction between the pipeline and the surrounding soil is a critical factor in the buckling analysis of the pipeline operating at high temperatures and pressures. The heating pipeline alters the temperature and induces excess pore pressure in the surrounding soil, which in turn affects the mechanical properties of the soil. Therefore, a comprehensive understanding of the thermo-mechanical response of the soil surrounding the pipeline during operation and shutdown is essential. To address this issue, this study developed a temperature-controlled pipe model test device that simulates the heating and cooling cycle of the pipe and the temperature field and pore pressure response of the surrounding kaolin clay. The test results showed that the soil temperature at the closest location to the pipe (0.1 D) reached a peak value of approximately 48.7°C when the pipe was heated from 12.5°C to 55°C. The peak temperature decreased with increasing distance, reaching 22.5°C at 0.875D. Heat transfer analysis using ABAQUS software revealed that the influence range of the pipeline on the soil temperature field during the heating cycle was about 2D. Additionally, a parametric study focused on the thermal conductivity (λsoil) of kaolin, and the best-fit value was determined to be 0.6 W/(m·°C. The excess pore pressures were generated in the kaolin surrounding the pipes during the heating cycle, and negative pore pressures were observed after cooling cycle. Furthermore, a theoretical solution for calculating the thermally induced pore pressure was derived, and preliminary verification showed good agreement between the theoretically computed and experimentally measured results. These findings provide valuable insights into the thermo-mechanical response of the soil surrounding pipelines during operation and shutdown, which can improve the design and safety of oil and gas pipelines.

A novel defect identification design of gas pipeline based on inverse heat conduction problem

A novel defect identification design of gas pipeline based on inverse heat conduction problem

Design of offshore gas pipelines against active tectonic fault movement

Active tectonic faults impose permanent ground actions on offshore gas pipelines that threaten their safety and service life. The seismic fault movement deforms the pipeline and causes excess strains due to bending, along with axial compressive or tensile forces depending on the fault type. This may lead to buckling, severe cross-sectional distortion and even rupture. The assessment of an offshore pipeline crossing active faults considers the estimation of the potential fault displacement, the structural response of the pipeline, and the limit-state capacity. This paper explores the design options for improving the capacity of partially embedded offshore pipelines to tolerate fault differential displacement using equations that are fitted to the results of finite element simulations and allow the prediction of the critical co-seismic fault displacement, i.e. the value of fault displacement that leads to various forms of pipeline failure. Considering all the types of faults, the influence of the parameters affecting the performance of an offshore pipeline subjected to active seismic fault rupture is quantified and discussed. The proposed equations could be used as guidance in the preliminary route design of future medium-diameter offshore pipelines and in the assessment of the vulnerability of existing ones. An illustrative example is also presented to demonstrate the application of the proposed equations.

ANN-Based Assessment of Soft Surface Soil Layers’ Impact on Fault Rupture Propagation and Kinematic Distress of Gas Pipelines

Large-scale lifelines in seismic-prone regions very frequently cross areas that are characterized by active tectonic faulting, as complete avoidance might be techno-economically unfeasible. The resulting Permanent Ground Displacements (PGDs) constitute a major threat to such critical infrastructure. The current study numerically investigates the crucial impact of soil deposits, which usually cover the ruptured bedrock, on the ground displacement profile and the kinematic distress of natural gas pipelines. For this purpose, a decoupled numerical methodology, based on Finite Element Method (FEM), is adopted and a detailed parametric investigation is performed for various fault and soil properties. Moreover, the advanced capabilities of Artificial Neural Networks (ANNs) are utilized, aiming to facilitate the fast and reliable assessment of soil response and pipeline strains due to seismic faulting, replacing time-consuming FEM computations. An extensive sensitivity analysis is performed to select the optimal architecture and training algorithm of the employed ANNs for both the geotechnical and structural parts of the decoupled approach, with suitable input and target values related to bedrock offset, fault and soil properties, surface PGDs, and pipeline strains. The proposed ANN-based approach can be efficiently applied by practice engineers in seismic design and route optimization of natural gas pipelines.

On a DSML Domain Server for Fluids Transmission Pipeline Design and Modeling

Domain specific modelling languages (DSMLs) are special purpose languages that have been designed and tailored for specific application domains. With domain specific features user of the language can construct with very familiar notations and get desired outcomes. The focus in this paper is on the functionality of a domain server in a domain specific modelling language for modelling oil and gas pipeline design. A domain server is coupled to a range of pipeline physical components by a pipeline context model, each of the components having a variety of pipeline built units, attributes and values. The domain server stores data received from at least one of the range of the pipeline physical components, the data including values associated with one or more attributes of the components. The domain server derives a model type for at least one phase from the lifecycle of the pipeline design operation for the first instance of the pipeline built units, based on analytics of information stored in the pipeline built units memory and the component attributes storage, where the model type includes a set of attributes for at least one of the range of pipeline physical components. In addition, the domain server generates an orientation for performance operation of an instance including one or more actions from the pipeline built units corresponding to at least one attribute of the set of attributes Keywords: Attribute sets, model type, built units, pipeline context model (PCM)

Optimal Route Selection of Offshore Pipelines Subjected to Submarine Landslides

Background: Offshore lifelines (i.e., pipelines and cables) are usually vulnerable to seabed deformations induced by earthquake-triggered geohazards, such as submarine landslides, soil liquefaction, and tectonic faulting. Since the complete avoidance of all areas characterized by offshore geohazards is not always techno-economically feasible, optimal lifeline route selection is deemed necessary for the safety and serviceability of every such infrastructure, in order to minimize the risk of severe environmental and economic consequences. Objective: The current study presents a decision-support tool for the design of offshore high-pressure gas pipelines, capable of performing: (a) the assessment of submarine landslides along a possible pipeline route (i.e., impact force and landslide width), (b) the assessment of their potential impact on the pipeline (i.e., pipeline strains), and (c) the optimal pipeline route selection. Methods: The advanced capabilities of GIS in lifeline optimal route selection are successfully combined with efficient (semi-)analytical models that realistically assess the response of offshore pipelines when subjected to axial or oblique loading conditions due to a submarine landslide. Results: The efficiency of the smart tool is presented through a case study of an offshore pipeline that is crossing potentially unstable slopes -under static and seismic conditions- in the Adriatic Sea. Five alternative routings are proposed based on the adopted design criteria when crossing the seismically unstable slopes and zones characterized by steep inclination. Conclusion: Provided that sufficient and reliable data are available, the developed decision-support tool can be efficiently used for deriving the potentially optimal route of an offshore pipeline.

Adoption of machine learning in estimating compressibility factor for natural gas mixtures under high temperature and pressure applications

One of the essential properties of natural gas is its compressibility factor (z-factor), which is required for the efficient design of natural gas pipelines, storage facilities, gas well testing, gas reserve estimation, etc. Its importance has led to the development of several approaches involving new laboratory methods, equations of state (EOS), empirical correlations, and artificial intelligence for estimating gas compressibility factors. Most of the developed Z factor models have a limited range of applicability. They are unsuitable for predicting Z factors of highly pressurized gas reservoirs and natural gas systems with pseudo-reduced temperatures less than 1. Where such models exist, they are scarce and less accurate. In this study, three machine learning models, including the Gradient Boosted Decision Tree (GBDT), Support Vector Regression (SVR), and Radial Basis Function-Neural Network (RBF-NN), were developed for predicting the z-factor of natural gas mixtures with a range of Ppr and Tpr of 0–30 and 0.92–3.0, respectively. The results showed that the Gradient Boosted Decision Tree (GBDT) model outperformed other selected machine learning algorithms and published correlations. The proposed model gave a superior coefficient of determination (R2 score), and root mean square (RMSE) of 0.99962 and 0.01033, respectively. Also, the variation of the Z factors from the GBDT model with pseudo-reduced pressures at different pseudo-reduced temperatures using the isotherm plot was found to be adequate. Hence, the GBDT model in this study is a reliable method for predicting Z factors of natural gas mixtures with Ppr and Tpr of 0–30 and 0.92–3.0, respectively. The plot revealed that the GBDT model performed extremely well in predicting compressibility factor with an MAPE of about 1%. The findings of this study shows that the proposed intelligent model can be utilized in predicting the gas Z-factor.