Gas Transmission Research Articles

Shale gas flow carrying liquid in gathering pipeline with different inclination angles

Shale gas reserves are abundant and widely distributed. As a green and clean energy source, it has tremendous development potential. Nonetheless, the shale gas transmission process is often accompanied by liquids. The gas transmission will transform to liquid-carrying gas transmission and liquid will accumulate in low-lying areas. These will accelerate pipeline corrosion and perforation, threatening pipeline safety and causing significant economic losses. In this paper, computational fluid dynamics (CFD) can be used to establish a transient model of liquid-carrying gas flow. The flow characteristics of liquid-carrying gas in the up-dip shale gas gathering pipelines are studied. The critical flow velocities at 10°, 20°, 30° can be determined 8.25 m/s, 9.5 m/s, 11 m/s. The critical flow velocity can provide a reference for discharging liquid efficiently in engineering. Combining the flow process with corrosion studies, we identified the main cause and the sensitive areas of flow-accelerated corrosion. Finally, we proposed recommendations to prevent pipeline accelerated corrosion. Thus, the flow-accelerated corrosion of shale gas pipelines can be minimized.

Explosion and vented explosion behaviors of low-concentration gas in large-scale pipes

The extraction, transmission, and use of low-concentration gas in coal mines are often challenged by potential accidents due to proximity to the combustion and explosion concentration limit. Water sealing of fire barriers and explosion venting devices guarantee the safe transmission of low-concentration gas. The propagation and venting of gas explosion under different concentrations are experimentally investigated in a DN500 mm pipe explosion propagation test system. The water sealing of fire barrier vented explosion field evolution of methane-air mixture at the stoichiometric concentration (9.5 vol%) is examined through Fluent numerical simulation to reveal the water sealing of fire barrier further vented explosion pattern of gas transmission pipelines under low concentrations. The explosion overpressure and flame propagation of low-concentration gas in pipes are observed and correlated. Based on their coupling relationship, the design basis for the installation location of the explosion venting device is derived. The vented explosion characteristics of low-concentration gas during pipe transmission are summarized, proving that this explosion venting technique enhances both the explosion venting device and explosion parameters. Our observations and analysis can offer useful clues to underground gas explosion and prevention in coal mines.

Machine-Learning-Based Classification for Pipeline Corrosion with Monte Carlo Probabilistic Analysis

Pipeline corrosion is one of the leading causes of failures in the transmission of gas and hazardous liquids in the oil and gas industry. In-line inspection is a non-destructive inspection for detecting corrosion defects in pipelines. Defects are measured in terms of their width, length and depth. Consecutive in-line inspection data are used to determine the pipeline’s corrosion growth rate and its remnant life, which set the operational and maintenance activities of the pipeline. The traditional approach of manually processing in-line inspection data has various weaknesses, including being time consuming due to huge data volume and complexity, prone to error, subject to biased judgement by experts and challenging for matching of in-line inspection datasets. This paper aimed to contribute to the adoption of machine learning approaches in classifying pipeline defects as per Pipeline Operator Forum requirements and matching in-line inspection data for determining the corrosion growth rate and remnant life of pipelines. Machine learning techniques, namely, decision tree, random forest, support vector machines and logistic regression, were applied in the classification of pipeline defects using Phyton programming. The performance of each technique in terms of the accuracy of results was compared. The results showed that the decision tree classifier model was the most accurate (99.9%) compared with the other classifiers.

Effect of Work Discipline on Employee Performance with Compensation as a Moderating Variable at PT Solusi Energy Nusantara

PT Solusi Energy Nusantara (SENA) is a subsidiary of PT PGAS Solution which is engaged in the transmission and distribution of natural gas where the company has been trusted by several large companies in Indonesia. However, employee performance has decreased by 7% in 2021 when compared to 2019, this will certainly affect the company's performance in facing future business competition. There are several factors that influence employee performance, one of which is compensation and work discipline. From the results of research conducted using the SEM AMOS method, it can be concluded that compensation has an effect on employee performance with a p-value of 0.001 while work discipline has no effect on employee performance with a p-value of 0.698. However, when compensation as a moderating variable will strengthen the relationship between work discipline and employee performance so that work discipline affects employee performance with a p-value of 0.002.

Constructing Gas Transmission Pathways in Two-Dimensional Composite Material ZIF-8@BNNS Mixed-Matrix Membranes to Enhance CO2/N2 Separation Performance

Two-dimensional (2D) nanomaterials, due to their high aspect ratio and high specific surface area, which provide a more tortuous pathway for larger gas molecules, are frequently used in membrane separation. However, in mixed-matrix membranes (MMMs), the high aspect ratio and high specific surface area of 2D fillers can increase transport resistance, thereby reducing the permeability of gas molecules. In this work, we combine boron nitride nanosheets (BNNS) with ZIF-8 nanoparticles to develop a novel material, ZIF-8@BNNS, to improve both CO2 permeability and CO2/N2 selectivity. Growth of ZIF-8 nanoparticles on the BNNS surface is achieved using an in-situ growth method where the amino groups of BNNS are complexed with Zn2+, creating gas transmission pathways that accelerate CO2 transmission. The 2D-BNNS material acts as a barrier in MMMs to improve CO2/N2 selectivity. The MMMs with a 20 wt.% ZIF-8@BNNS loading achieved a CO2 permeability of 106.5 Barrer and CO2/N2 selectivity of 83.2, surpassing the Robeson upper bound (2008) and demonstrating that MOF layers can efficiently reduce mass transfer resistance and enhance gas separation performance.

Shale gas transport model considering gas adsorption and desorption

The gas migration mechanism and apparent permeability in shale reservoirs are significantly different from those in conventional gas reservoirs, which is mainly caused by nanoscale phenomena and organic matter as gas storage and supply media. However, in shale reservoirs, gas flow behavior plays an important role in well performance, so it is necessary to develop a new apparent permeability model considering gas transport mechanism. Therefore, in order to study the change of matrix permeability under different pressures in the development process of shale adsorption layer, combined with previous studies, considering the seepage mechanism of stress sensitivity, real gas effect and adsorption, a new model of apparent permeability is created by combining multiple gas transmission mechanisms. The sensitivity analysis of the new model is carried out by changing the corresponding parameters, and the corresponding conclusions are drawn. In this work, the established model can accurately calculate the apparent permeability of viscous flow, Knudsen diffusion and desorption, which makes us have a more accurate understanding of the transmission mechanism of shale gas and contributes to the efficient and sustainable development of shale gas.

Effects of gas-diffusion layer properties on the performance of the cathode for high-temperature polymer electrolyte membrane fuel cell

The role of the gas-diffusion layer (GDL) in high-temperature polymer electrolyte fuel cell (HT-PEMFC) differs from that in low-temperature PEMFC GDL due to operating conditions and environment. Determining the GDL's structural parameters that affect its transport properties, and how these properties impact HT-PEMFC performance was urgently required. Four commercial GDLs were employed in HT-PEMFC cathode's GDE and was examined using X-μCT, mercury intrusion porosimetry, and an optical microscope to analyze structural parameters and characteristics. Fractal theory was applied to comprehend the gas transmission property of GDL, and the validity of the theory was confirmed through ex-situ through-plane gas permeability measurement. The analysis indicated that the porosity of GDL influenced by the crack region of the MPL has more impact on the GDL's gas transmission than its thickness. After that, we established a correlation between HT-PEMFC cathode performance and GDL porosity and theoretical gas transmission properties using R2 coefficient of determination.

Reliability-oriented optimal sizing of power-to-gas and combined heat and power technologies in integrated electricity and natural gas transmission systems

Integration of electricity and natural gas systems is a promising solution to enhance the overall efficiency and reliability of the energy systems. The combined heat and power (CHP) and power-to-gas (P2G) technologies are first-rate options to integrate an electrical power system with a natural gas network. Accordingly, unlike previous works that considered only one technology in their studies, this paper proposes an optimization framework to determine the optimal sizing of both CHP and P2G technologies in the integrated electricity and natural gas systems. In addition, although previous researches proved the impacts of the P2G and CHP units on energy system reliability, this criterion has been neglected in optimal sizing of these technologies. To narrow research gaps, this paper employs a detailed energy flow model along with a sequential Monte Carlo-based reliability evaluation method within the proposed optimization framework. The proposed optimization problem aims to minimize the investment, operation, and reliability costs subject to economical and operational constraints. The proposed method is tested on an integrated IEEE 24-bus electrical power system and 20-node Belgian natural gas system. The simulation results demonstrate the effectiveness and applicability of the proposed reliability-oriented sizing method and prove how considering the reliability cost in the objective function can reduce the total cost.

Discovery of potential risks for the gas transmission station using monitoring data and the OOBN method

Discovery of potential risks for the gas transmission station using monitoring data and the OOBN method

Prospects for the Development of Eurasian Integration in the Field of Expanding Export Cargo Flows of Russian Gas to Friendly Countries amid the Escalation of the Energy Crisis in the World

Aim. In 2022, the shortage of energy carriers on the world market was directly affected by sanctions against the Russian energy sector and terrorist attacks on the Nord Stream and Nord Stream —2 gas pipelines, while scientific publications do not present global calculations of the volumes of Russian gas falling out of world circulation. The aim is to assess the volumes of Russian gas falling out of global turnover.Tasks. Identification of prospects for the development of Eurasian integration in the field of expanding export cargo flows of Russian gas to friendly countries against the background of the escalation of the energy crisis in the world taking into account exogenous and endogenous factors influencing changes in the production and consumption of Russian gas.Methods. Methods of system and comparative analysis, scientific generalization, expert assessments, forecasting methods.Results. The author presents an analysis of Russia’s role in global gas s upplies, an assessment of falling export volumes, as well as a short-term forecast of changes in pipeline gas cargo flows according to optimistic, basic and pessimistic scenarios.Conclusion. According to the author, in order to exclude significant losses in gas production in Russia and to implement an optimistic scenario, it is important to accelerate the timing of the unification of the western and eastern gas transmission systems, as well as the implementation of investment projects for the construction of gas pipeline capacities “Power of Siberia — 2”, “Soyuz — Vostok”, “Turkish Stream — 2”.

Prediction of corrosion failure probability of buried oil and gas pipeline based on an RBF neural network

Risk assessment is critical to ensure the safe operation of oil and gas pipeline systems. The core content of such risk assessment is to determine the failure probability of the pipelines quantitatively and accurately. Hence, this study combines the MATLAB neural network toolbox and adopts an Radial Basis Functions (RBF) neural network with a strong non-linear mapping relationship to build a corrosion failure probability prediction model for buried oil and gas gathering and transmission pipelines. Based on the hazard identification of pipeline corrosion failure, the model summarizes the causes of corrosion failure and determines the input and output vectors of the neural network based on the fault tree. According to the selected learning samples, through the design and training of network parameters, the RBF neural network that can predict the system failure probability is finally obtained. Taking the failure probability of 30 groups of high-pressure gathering and transmission pipelines of gas storage as an example, the capability of inputting the probability of the bottom event and outputting the probability of the top event is demonstrated through training data. Our results show that the calculated failure probability based on the fault tree analysis model is consistent with the predicted failure probability based on the RBF neural network model. Hence, the RBF neural network model is shown to be reliable in predicting the corrosion failure probability of buried pipelines.

SECURITY OF NATURAL GAS SUPPLY TO CONSUMERS IN UKRAINE AND POLAND IN THE FACE OF OPEN RUSSIAN MILITARY AGGRESSION IN 2022 (COMPARATIVE STUDY)

Security of natural gas supply to consumers in Ukraine and Poland in the face of open Russian military aggression in 2022 (comparative study).
 Military operations, including Russian attacks on natural gas production sites controlled by Ukraine and network restrictions, have led to a 7 % year- on-year decline in natural gas production and the temporary loss of natural gas access for hundreds of thousands of Ukrainian consumers. In 2022, 18,5 bcm of natural gas is likely to have been produced. The autumn suc- cesses on the frontline allowed Ukraine to start clearing damage on reco- vered territories and increase the number of new drillings.
 The extensive damage to companies using natural gas in production that was caused by Russian attacks and the scale of emigration reduced natural gas consumption in Ukraine by a quarter. Nevertheless, imports were ne- cessary. It was most profitable for the government in Kyiv to bypass transit costs and buy part of the natural gas supplied from Russia via Ukraine to the EU.
 Due to the cost of transit, a smaller part of the gas acquired by Ukraine was from other countries (e.g. Norway). The amount of natural gas (owned and owned by foreign companies) in storage in Ukraine at the end of October was 14,2 bcm. In the end, from its western partners Ukraine probably im- ported a total of only 1,5 bcm. Likely, some of the natural gas owned by foreign counterparties stored in Ukrainian storage facilities was purchased. As of 2021, the demand for Polish customers was lower than for Ukrainian needs. According to preliminary data, some 16,15 bcm of natural gas was sent to Polish consumers in 2022. Probably mainly due to the authorities’ protective moves towards households, natural gas transmission to domestic consumers in Poland fell by only less than 17,5 % compared to 2021. Indus- trial use of natural gas has decreased more.
 The Polish authorities have completed many investments (or made progress in this area) in natural gas infrastructure long postulated by experts. The degree of depletion of deposits and the high capital intensity of natural gas exploration and production requires a significant increase in investment in natural gas exploration and production to stop the further decline in natural gas production in both countries.

A review of hydrogen embrittlement in gas transmission pipeline steels

Abstract Hydrogen transport by blending hydrogen into natural gas transmission pipelines and by pure-hydrogen pipelines is a prospective mode of energy transmission during the transition to renewables. The risk of hydrogen embrittlement (HE) in pipeline steels must first be quantified to ensure safe pipeline operation. This review provides an overview of HE in pipeline steels. Most pipeline steels have reduced ductility when exposed to hydrogen partial pressures of 100 bar and above. Higher-strength pipeline steels (X80 and X100) have been found to undergo HE at ∼50 bar hydrogen. Hydrogen-induced subcritical crack growth in pipeline steels has not been reported in the literature. There are few articles on HE in pipeline welds, with some indications that the weld is more susceptible to HE, and some indications that it is less. The relationship between hydrogen pressure and absorbed hydrogen concentration has not been evaluated. Gaps in knowledge are identified in the conclusions.

Leaf porous structure Inspired packaging film for fruits preservation and monitoring CO2 concentration of package

The preservation of fresh fruit and vegetables is always a challenge. Equilibrium modified atmosphere packaging (EMAP) is ideal for preserving fresh produce. The gas transmission and selectivity of EMAP films is crucial for achieving atmospheric equilibrium in packaging. Inspired by leaf porous structure regulating their gas exchange function, we selected natural porous diatomite as the gas channel and modified it with polyethyleneimine (PEI). By introducing diatomite into the film matrix of CNFs, the gas transmission and CO2/O2 selectivity of EMAP films were regulated. The atmosphere in all the packages of EMAP films reached equilibrium within 24 h, which kept the fruit in low intensity aerobic respiration. The EMAP film of DgP7.5 (O2 transmission rate 43.33 cc m−2 day−1 bar−1, CO2/O2 selectivity 1.56) was found to be the most suitable for packaging litchis and green plums. Diatomite with porous structures will provide a design concept for EMAP films.

Hydrogen blending in existing natural gas transmission pipelines: a review of hydrogen embrittlement, governing codes, and life prediction methods

Abstract Existing natural gas pipelines provide an economic alternative for the transport of hydrogen (H2) in an envisioned hydrogen economy. Hydrogen can dissolve in the steel and cause hydrogen embrittlement (HE), compromising pipeline structural integrity. HE causes subcritical cracking, decreases ductility and fracture toughness, and increases the fatigue crack growth rate (FCGR). This work analyzes the testing standards in gaseous hydrogen used to quantify those effects. Design code ASME B31.12 applicable to hydrogen pipelines has more stringent requirements than ASME B31.8 code commonly used for constructing natural gas pipelines. Differences in materials requirements specified by those codes are summarized. ASME B31.12 pipeline code applies for H2 at a concentration greater than 10% molar. However, recent testing programs acknowledge that H2 degrades steel mechanical properties regardless of its percentage in the blend. This paper discusses how the hydrogen degraded mechanical properties affect pipeline integrity. Decreased mechanical properties cause a drop in the failure pressure of a flawed pipeline, calculated following a fitness for service methodology. There is an increasing risk of subcritical crack growth in H2 as the hardness of base metal and welds increases. This paper analyzes where zones with high hardness and susceptible microstructures are expected in existing pipelines.

The Influence of Axial Compressive Stress and Internal Pressure on a Pipeline Network: A Review

Due to their exceptional structural integrity, steel pipelines are the main component for oil and gas transmission. However, these pipelines are often affected by corrosion, despite corrosion protection, because of harsh working conditions. In addition to corrosion defects, pipelines are often subjected to multiple external loads. The combination of corrosion defects and external loads can significantly reduce the failure pressure, resulting in various failure behaviors. This reduction in failure pressure is especially critical in pipe bends as they are the weakest link in a pipeline. This paper presents an overview of the failure behavior of corroded steel pipe components subjected to internal pressure and axial compressive stress.

Faster RSTRENG: A More Efficient Effective Area Method Algorithm for Corrosion Assessment

AbstractCorrosion is one of the major threats to the safety and structural integrity of oil and gas transmission pipelines. The corrosion threat is usually managed by regular in-line inspection (ILI). The effective area method (RSTRENG) is the most popular corrosion assessment model to convert the measured corrosion size to predicted burst pressure. Given a detailed corrosion measurement profile, the effective area method involves an iterative process to find the minimum burst pressure. As stated in ASME B31G, “for a corroded profile defined by n measurements of depth of corrosion including the end points at nominally full wall thickness, n!/2(n − 2)! iterations are required to examine all possible combinations of local metal loss with respect to surrounding remaining material,” the widely used effective area algorithm has at least an order of n-square time complexity (O(n2)). As n increases, the computation time increases nonlinearly. This paper reviewed the traditional RSTRENG algorithm first, and demonstrated that it is not necessary to always loop through all the combinations and check the corresponding burst pressure one by one. Because some combinations with shallower and shorter corrosion size are certainly not the final critical combination corresponding to the minimum burst pressure. A more efficient algorithm (Faster RSTRENG) is proposed and presented in this paper, which can reduce the algorithm computation time significantly.

A New Porous Nozzle for Aluminum Melts Purification—Preparation and Mathematical–Physical Model

Aluminum and its alloy castings are used more and more widely, and it is particularly important to remove impurities in the alloy. According to the principle of bubble floatation for degassing aluminum melt, a new porous nozzle with controllable pores was developed, and a hydraulic simulation experimental device was studied with the nozzle. The effects of the particle size ratio of the coarse sand to fine sand and volume fraction of fine sand on the porosity of the porous nozzle were studied by orthogonal experiment, and permeability and compressive strength of the porous nozzle were used as test indicators to determine the optimal parameters of preparation for the porous nozzle. The optimal parameters are fine sand of 100 mesh, and fine sand of 50 wt.%, binder of 17.5 wt.%, pore-forming agent of 6 wt.%, and pressure of making sample of 5 MPa. The nozzle with optimal parameters was prepared and tested, and the permeability is 112.2 × 10−12 m2 and the compressive strength is 2.3 MPa. In addition, a physical model of gas transmission in the porous nozzle was proposed. With the increase in the proportion of fine sand, the permeability of the porous nozzle decreases, the compressive strength increases, and the calculated porosity increases. The hydraulic simulation of melt injection was carried out, and the mathematical model for calculating the bubble diameter of bubble floatation was formulated. The model shows that the bubble diameter increases with the increase in gas flow rate. The experiment shows that the prepared porous nozzle has the merits of a simple preparation process and low-cost, which is expected to degas aluminum melts.

Numerical simulation of natural gas flow characteristics and hydrate formation risk in deepwater submarine pipelines

The development of flow assurance technology in submarine pipelines affects the safety, efficiency, and economy of deepwater natural gas development. In this study, in order to accurately predict the hydrate formation risk in deepwater submarine pipelines, a novel mathematical prediction model of hydrate formation risk has been established. The model has been applied and sensitivity analysis of typical factors has been carried out. The model prediction results show that: (1) Due to the low temperature of the seabed, hydrate formation region (HFR) often exists in submarine pipelines. (2) When other conditions are constant, hydrate formation region increases with the decrease in seawater temperature. (3) When other conditions are constant, the temperature drop, and the length of hydrate formation region decrease with the increase of gas transmission rate. (4) When other conditions are constant, the temperature drop, and the length of hydrate formation region decreases with the increase of gas transport temperature. (5) Reasonable setting of gas transmission temperature and gas transmission rate can help to reduce the hydrate risk and consumption of inhibitors during submarine natural gas transmission.

Use of Profilometry‐Based Indentation Plastometry to Study the Effects of Pipe Wall Flattening on Tensile Stress–Strain Curves of Steels

Herein, the flattening and subsequent tensile testing (in the hoop direction) of steel pipes used for transmission of oil and gas are concerned. A particular focus is on the use of a novel indentation plastometry test (PIP), applied to the outer free surface of an as‐received pipe. This allows a stress–strain curve to be obtained from a relatively small volume (a disk of diameter about 1 mm and thickness around 100–200 μm). Whole section and reduced section tensile testing, of as‐received and flattened samples are carried out. Four different pipes are studied. While there are some variations between them, there is a general trend for near‐surface regions of the pipe to be a little harder than the interior, and for flattened pipes to be a little harder than unflattened ones, although these are not dramatic or well‐defined effects. PIP testing also confirms that these pipes exhibit little or no anisotropy. It is in general concluded that PIP‐derived stress–strain curves for testing of the outside of a pipe are likely to be quite close to those obtained by tensile testing of the whole section in the hoop direction, after flattening.