Natural Gas Transmission Research Articles

Solar hydrogen for high capacity, dispatchable, long-distance energy transmission – A case study for injection in the Greenstream natural gas pipeline

This paper presents the results of techno-economic modelling for hydrogen production from a photovoltaic battery electrolyser system (PBES) for injection into a natural gas transmission line. Mellitah in Libya, connected to Gela in Italy by the Greenstream subsea gas transmission line, is selected as the location for a case study. The PBES includes photovoltaic (PV) arrays, battery, electrolyser, hydrogen compressor, and large-scale hydrogen storage to maintain constant hydrogen volume fraction in the pipeline. Two PBES configurations with different large-scale storage methods are evaluated: PBESC with compressed hydrogen stored in buried pipes, and PBESL with liquefied hydrogen stored in spherical tanks. Simulated hourly PV electricity generation is used to calculate the specific hourly capacity factor of a hypothetical PV array in Mellitah. This capacity factor is then used with different PV sizes for sizing the PBES. The levelised cost of delivered hydrogen (LCOHD) is used as the key techno-economic parameter to optimise the size of the PBES by equipment sizing. The costs of all equipment, except the PV array and batteries, are made to be a function of electrolyser size. The equipment sizes are deemed optimal if PBES meets hydrogen demand at the minimum LCOHD. The techno-economic performance of the PBES is evaluated for four scenarios of fixed and constant hydrogen volume fraction targets in the pipeline: 5%, 10%, 15%, and 20%. The PBES can produce up to 106 kilotonnes of hydrogen per year to meet the 20% target at an LCOHD of 3.69 €/kg for compressed hydrogen storage (PBESC) and 2.81 €/kg for liquid hydrogen storage (PBESL). Storing liquid hydrogen at large-scale is significantly cheaper than gaseous hydrogen, even with the inclusion of a significantly larger PV array that is required to supply additional electrcitiy for liquefaction.

Recent Advances to Overcome Methane Hydrate Formation Challenges Using Nanostructure Promoters: A Mini Review Towards Industrialization

Natural gas has recently drawn considerable attention due to its low emissions upon combustion. Pipeline transmission of natural gas is costly and always encounters different obstacles. Therefore, an effective industrial alternative for the storage and transmission of natural gas is needed. Hydrates, also known as solidified natural gas, have been proven to be a more feasible replacement compared to pipeline transmission, CNG, or LNG. Scientists have introduced promoters to shorten the induction time, increase the storage capacity, and improve the stability of hydrates. Nanostructure materials have demonstrated promising promotion results, suggesting a bright future and a critical step in the industrialization of this technology. Researchers have mainly used pure methane, which is the main component of natural gas, to form hydrates. In this article, the fundamentals of the selection of a nanopromoter, the hydrate formation process, and related calculations are demonstrated. Finally, recent results have been brought together to provide an overview of advances towards the use of nanostructure promoters to tune hydrates for future industrial processes.

Experimental Investigation into Liquid and Solid Separation by an Industrial Mesh-Vane-Type Separator on Natural Gas at 4–5 MPa, Different Liquid Loadings and Gas Flows

AbstractInline vertical separators are commonly employed in natural gas transmission facilities (e.g., receipt stations) to filter liquid contaminants such as compressor oil, glycol, and free water from the gas stream. Manufacturers of these separators have claimed liquid removal efficiencies of 98–99% for droplet sizes ≥ 8 μm. However, these contaminants have been found invariably in piping systems downstream of these separators, suggesting inadequate separator performance. Currently, there is a lack of ability to verify manufacturer claims due to difficulties in quantifying liquid contaminants and droplet characteristics. The potential consequences of having such contaminants include lower gas quality, impaired gas metering accuracy, corrosion and damage to equipment/instrumentation, and adverse impacts on industrial and residential end users. This paper presents performance testing of a mesh-vane-type vertical separator conducted on high pressure, pipeline quality, natural gas in the range of 4–5 MPa and flow velocity in the range of 1.3–13 m/s in the DN150 separator inlet (hence turndown ratio of 10:1). Four different spray nozzles were used to inject and atomize industrial compressor oil with a liquid-to-gas mass loading ratio of 0.06–1.8%. Test results revealed that the average bulk efficiency separation performance for this separator is approximately 90.34%. This was found to be independent of the liquid-to-gas mass loading ratio. The effective Souders–Brown K-factor was found to be 0.15 m/s. This is below literature published data in the range of 0.27–0.3 m/s for horizontal flow, vane-pack-type separators. Liquid separation tests were also conducted following the injection of solid glass beads. Liquid separation efficiency decreased by approximately 9%, following the injection of 7 kg of industrial glass beads over a period of approximately 4 h. This was attributed to accumulation of solids in the vane pack.

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.

Binary Sacrificial Coatings for Internal Corrosion Protection of Natural Gas Transmission Pipelines

One of the top reasons for the leaks in natural gas transmission pipelines is related to the internal corrosion of steel pipelines, mainly due to the presence of incidental H2O and CO2 in the line. Adding a protective coating or liner to the inner pipe surface reduces internal corrosion; however, conventional coatings (e.g., paint, epoxy, polyethylene, etc.) are insufficient to provide long-term corrosion resistance due to the permeation of the corrosive species such as H2O, CO2, Cl-. This research aimed to investigate the corrosion behavior of binary sacrificial coating for the protection of pipeline steel in a CO2-saturated aqueous electrolyte under natural gas pipeline conditions.Two types of the cold spray binary metallic coatings (ZnCr, ZnNb) were studied using electrochemical techniques: potentiodynamic polarization (PDP), linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). The evaluation of the corrosion resistance of cold spray binary metallic coatings (ZnCr, ZnNb) was carried out in an environment containing 3 barg CO2 pressure, simulating the partial pressures that are found in gas transmission over a solution of 3.5 wt.% NaCl heated to 40 ºC. Post-corrosion surface characterization was performed using scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS).The EDS mapping analysis and XRD results revealed the presence of ZnCO3 layer. EDS analysis showed that no Cr was detected on the surface of ZnCr coating after 24 hours of exposure. This may be due to a thick layer of ZnCO3 formed on top of the ZnCr coating. The obtained data showed that cold spray binary metallic coatings (ZnCr, ZnNb) can be used as sacrificial anodic materials to protect the interior of the steel pipeline against CO2 corrosion in a natural gas transmission environment. Furthermore, self-healing properties of the binary metallic coatings were demonstrated as protective corrosion products formed on the damaged regions of the coating.Keywords : CO2 corrosion, natural gas pipelines, cold spray coatings, zinc alloy, sacrificial coatings, self-healing coatings, electrochemical reaction autoclave

Hazardous air pollutants in transmission pipeline natural gas: an analytic assessment

Natural gas production occurs in specific regions of the US, after which it is processed and transported via an interconnected network of high-pressure interstate pipelines. While the presence of hazardous air pollutants (HAPs) in unprocessed, upstream natural gas has been documented, little has been published on their presence in the midstream natural gas supply. We systematically evaluated publicly available, industry-disclosed HAP composition data sourced from Federal Energy Regulatory Commission (FERC) natural gas infrastructure applications submitted between 2017 and 2020. Natural gas composition data from these filings represent approximately 45% of the US onshore natural gas transmission system by pipeline mileage. Given that reporting natural gas HAP composition data is not required by FERC, only 49% of approved expansion projects disclosed natural gas HAP composition data. Of those applications that disclosed composition data, HAP concentrations were typically reported as higher for separator flash gas and condensate tank vapor compared to liquefied natural gas and transmission-grade natural gas, with mean benzene concentrations of 1106, 7050, 77, and 37 ppm respectively. We also identified one pipeline operator that reports real-time HAP concentrations for its natural gas at five pipeline interconnection points. Similar to the FERC applications, this operator reported benzene, toluene, ethylbenzene, xylenes and hydrogen sulfide as present in transmission pipeline natural gas. Notably, mercury was also reported as detectable in 14% of real-time natural gas measurements but was not reported in any FERC applications. Given that transmission infrastructure releases natural gas during uncontrolled leaks and loss of containment events as well as during routine operations (e.g. blowouts and compressor station blowdowns), these gas composition data may serve as a critical component of air quality and health-focused evaluations of natural gas releases.

Preventing the Formation of Methane Hydrates in Natural Gas Transmission Pipelines–A Comprehensive Review

Hydrates are usually formed during the transportation and treatment of natural gas, resulting in hydrate plugging of pipelines. Hydrates are crystal like structure being formed from the mixture of gas and water. They occur at low temperature and highpressure conditions. These hydrate plugs cost the oil and gas industry significant amounts in revenue cuts and is a major problem for the industry. There are many preventive measures that can be implemented such as inhibitors to avoid the formation of hydrates. This paper aims to highlight the different measures and analyse their effectiveness for hydrate-plug prevention. One such method for the reduction of hydrate formation is the removal of existing hydrates by using different types of inhibitors. The most common method of hydrate prevention in deep-water developments is injection of thermodynamic inhibitors, which include methanol, glycols, and others. If hydrate prevention methods are unsuitable and hydrates are liable to form, the process of dehydration can be used wherein the water gets removed from the gas stream. Electrical heating is also used as a way to dehydrate the pipe. This paper compares a variety of inhibitors and various hydrate preventive methods and discusses their influence in the mitigation of hydrate formation in gas pipelines.

Failure analysis of a natural gas transmission X60 steel pipeline

PurposeThis paper aims to investigate the reason for natural gas leakage from transmission pipelines between Linyi and Shouguang in China during sealing tests, explore the failure mechanism and provide a reference for taking reasonable measures to prevent such accidents.Design/methodology/approachFailure analysis for the steel pipe has been addressed with different methods, such as microstructure analysis, inclusion analysis, corrosion product analysis, macro- and micro-morphology analyses and bacterially catalyzed experiments.FindingsSeveral bulges were observed, especially at the bottom of the steel pipe sample, with the distribution and positioning not related to the weld. The inner surface of the steel pipe was severely corroded, and the oxide scale was flaking in many places. The greatest corrosion area was identified at the bottom of the steel pipe near the gas leakage point. Severe pitting and perforation corrosion in the pipeline were observed, and the main corrosion reaction products were Fe3O4, FeO and FeS. The grain orientation distribution near the crack (coarse grains <101> and fine grains <111> at the microcrack tip) indicates that fine grains may be beneficial in hindering crack propagation.Originality/valueThe principal mechanism for the corrosion failure is supposed to be due to the interaction of chloride ions with the sulfate-reducing microorganisms present and the stress corrosion cracking by chloride and sulfide formed by the sulfate-reducing microorganisms.

Development of a consequence-based decision-making framework for natural gas transmission pipeline

Development of a consequence-based decision-making framework for natural gas transmission pipeline

Effect of pipe orientation on erosion of π-shaped pipelines

Erosion of particles in elbows mounted in series is a detriment in the course of natural gas transmission. The flow and erosion characteristics of π-shaped pipelines were investigated via coupling the computational fluid dynamics (CFD) and the discrete phase model (DPM) method. The effect of pipe orientation on particle erosion was mainly studied. Spiral and asymmetrical trajectories of particles were observed from the second elbow to the downstream straight pipe of the fourth elbow in the non-coplanar π-shaped pipelines. The integral erosion rate of the first elbow increased by 0.35%, and it grew by 72.49% and 87.48% in the second and fourth elbows in non-coplanar structures, respectively, while the integral erosion rate of the third elbow reduced by 32.94%. In the actual transportation of natural gas, it is necessary to make local thickening treatment of the second and fourth elbow of the non-coplanar π-shaped pipelines. • A swirling effect was discovered in non-coplanar structures. • Spiral and asymmetrical particle trajectories were generated. • Integral erosion degree of fourth elbow increased by 87.48% due to swirling effect. • The erosion rate increased exponentially with the increase of velocity.

E&amp;P Notes (August 2022)

E&amp;P Notes (August 2022)

A Frequency–Pressure Cooperative Control Strategy of Multi-Microgrid with an Electric–Gas System Based on MADDPG

With the development of micro gas turbines (MT) and power-to-gas (P2G) technology, the electric–gas system plays an important role in maintaining the stable, economical, and flexible operation of the microgrid. When subjected to power load disturbance and natural gas load disturbance, the system controller needs to coordinately control the frequency of the microgrid and the gas pressure at the natural gas pipeline nodes. Additionally, the reliability and stability of a multi-microgrid system are much higher than that of a single microgrid, but its control technology is more complicated. Thus, a frequency–pressure cooperative control strategy of a multi-microgrid oriented to an electric–gas system is proposed in this paper. Firstly, based on the analysis of the operating characteristics of the natural gas network and the coupling equipment, the dynamic model of natural gas transmission is built. Secondly, a multi-microgrid load frequency control model including MT, P2G equipment, electric vehicles (EVs), distributed power sources and loads has been established. In addition, according to the three control objectives of microgrid frequency, node pressure and system coordination and stability, the structure of a Muti-Agent Deep Deterministic Policy Gradient (MADDPG) controller is designed, then the definition of space and reward functions are completed. Finally, different cases are set up in the multi-microgrid, and the simulation results are compared with PI control and fuzzy control. The simulation results show that, the proposed MADDPG controller can greatly suppress the frequency deviation caused by wind power and load disturbances and the air pressure fluctuations caused by natural gas network load fluctuations. Additionally, it can coordinate well the overall stability between the sub-microgrids of multi-microgrid.

Coordinated operation of electricity and gas-hydrogen systems with transient gas flow and hydrogen concentration tracking

This paper addresses the problem of coordinating the operation of electricity and natural gas (NG) transmission systems with green hydrogen (H2) production and injection into existing NG networks. In particular, the operation of the two systems consists of a two-stage optimization framework that solves a network-constrained unit commitment (UC) problem with transmission power losses to obtain the profiles of gas energy demands from gas-powered generators and the maximum allowable H2 injection flow rates from power-to-gas (PtG), which are then used as inputs to an optimal transient NG-H2 flow problem with H2 concentration tracking. The nonlinearities introduced by the discretization of the H2 concentration tracking equations are particularly challenging to solve using second-order nonlinear programming (NLP) methods. Moreover, the nonlinear constraints capturing transmission line losses make the electricity operational problem intractable if solved with mixed-integer NLP methods. Therefore, this work leverages the reliability and scalability of linear programming (LP) by designing two novel and distinct sequential LP (SLP) methods that exploit the particular structures of the two problems to find feasible, possibly optimal solutions, using only first-order information. The algorithmic framework is demonstrated on the IEEE 24-bus RTS connected to the 22-node Belgian gas network. This paper is the first to demonstrate H2 concentration tracking under transient gas flow in a multi-energy optimization framework on a realistic gas transmission network with multiple H2 injection locations.

Aspects of the introduction of alternative gas fuels and their influence on the quality of natural gas

The paper announces that the Ministry of Energy and Environmental Protection of Ukraine has developed the “Ukrainian Green Deal”, the ambitious goal of which is the transition to a climate-neutral economy, reducing greenhouse gas emissions and decarbonizing the economy by 2070. The “European Green Deal” provides for the achievement of similar goals by 2050. It is mentioned that the share of biomethane and “green” methane in the overall system of transmission and consumption of natural gas is planned to increase. The process of biomethane production by biogas enrichment and carbon dioxide separation is described. The perspective course of pure hydrogen production by water electrolysis due to the use of excess “green” energy from solar and wind power plants is noted. The way of complex integration of biomethane and “green” hydrogen production is suggested. The process of “methanation”, i.e. the conversion of “green” hydrogen and carbon dioxide as a waste product in the production of biomethane is described. The readiness of the NAAU to accredit verification bodies of greenhouse gas emission due to the introduction of the greenhouse gas emission allowance trading in Ukraine was stated. The calculation of the combustion heat values, density and Wobbe number for natural gas when mixed with pure hydrogen has been simulated. It is pointed that when the heat of combustion decreases and exceeds the permissible limits, the Wobbe number does not exceed the minimum set value, which indicates the absence of the need to replace gas-consuming equipment. It is argued that if it is necessary to increase the combustion heat of a mixture of natural gas with hydrogen, it is necessary to enrich it with “heavy” hydrocarbon gases.

Analisis Kualitas Produk di PT. Adi Kuasa Gasindo Medan

PT. Adi Kuasa Gasindo, Medan is a provider engaged in the transmission and distribution of natural gas. The formulation of the problem in this research is “How is the product quality applied to PT. Adi Power of Gasindo, Medan?” The purpose of the study was to find out what was applied at PT Adi Power Gasindo Medan. The research method that the author uses is a qualitative descriptive research method. The data collection technique used by the author is a structured interview technique. From the results of interviews with the warehouse head and admin staff, information was obtained that the product quality at PT. Adi Power of Gasindo is still not good. improve quality control so that no product damage is presented to customers, give customers the opportunity to provide input on new products, as well as provide advance warning about damage that can cause large losses, without having to burden employees

Stochastic Simulation of Flow Rate and Power Consumption Considering the Uncertainty of Pipeline Cracking Rate and Time-Dependent Topology of a Natural Gas Transmission Network

Various gas pipeline networks used for the transit of energy sources are some of the most important infrastructures. However, carrying gas from one point to another is not the only concern when planning the construction of a new network or expanding an already existing one. The reliability and environmental impact of the system are crucial when evaluating the network and risks posed by potential gas leaks, fires, explosions, etc. Even though everyone admits that reliability is a key aspect of any system, its constraints will still be most likely neglected in the assessment of the pipeline project. How much energy is wasted by pushing an additional amount of gas through the pipeline network, which will eventually gush out of the pipeline because of one crack or another? Moreover, if this additional power or fuel consumption and related environmental impact are significant, how could it be reduced? In this paper, an approach is introduced for the simulation and quantification of how much more power would be required if the pipelines are regarded as unreliable (i.e., by leaking, rupturing, or even exploding). By employing stochastic simulations and time-dependent topology (topology determined by the value of a variable representing time) of the pipeline network as a case study for the selected representative gas transmission network, the amount of additional power consumption in gas compressor stations due to uncertain cracking and the leaking rate was evaluated. Although the analysis of power consumption was performed for a hypothetical network, the estimates of the cracking rates, detection effectiveness, and leaking rates used were as close to the real cases as possible.

Insights into the perforation of the L360M pipeline in the liquefied natural gas transmission process

The cause of the failure of a liquefied natural gas transmission pipeline that has experienced internal corrosion during the water injection, idle and transmission processes, is fully investigated in this work. There are two significant features of pipeline failure, namely, the perforated location at the 6o’clock position and under scales deposit. Hence, the 2# leakage point and corrosion scale character were investigated in this research. The perforation of pipeline is attributed to three consecutive stages: (a)corrosion scale formation and pitting initiated, (b) the thickening of the scales and pitting propagation, and (c) the deposit of scales and pitting growth. Among of that, the deposited scales accelerate the pits growth during the LNG transmission process. Meanwhile, the premise cause of the failure was the scales deposit and pits initiation, pits propagation caused in water injection and idle processes.

Leak detection and repair data from California's oil and gas methane regulation show decrease in leaks over two years

Leak detection and repair (LDAR) programs are commonly used to identify and mitigate unintentional emissions at oil and gas facilities. This study utilizes regulatory reporting data from 2018 to 2019 at over 300 facilities (including crude oil production, natural gas production, natural gas storage, and natural gas transmission) to evaluate the effectiveness of California's statewide LDAR requirements. The results from this study can offer guidance for other jurisdictions looking to reduce methane emissions from oil and gas facilities. Total leaks found in 2018 and 2019 were 11,359 and 7,208, respectively. Although the number of components surveyed increased from 2018 to 2019 by 16%, the number of leaks decreased over the eight quarterly surveys (slope [95% confidence interval]: -287 leaks/quarter [-395, -180]). In both 2018 and 2019, 20% of all leaks accounted for approximately 50% of estimated emissions from leaking components, demonstrating the importance of frequent LDAR surveys to mitigate emissions from larger leaks. Emission reductions from LDAR surveys were estimated by using correlation equations to roughly approximate emission rates based on measurements of concentration. In 2018 and 2019, emission reductions were 5,400 and 3,000 metric tons methane, respectively (∼9% and ∼4% of total fugitive methane emissions from oil and gas production and processing according to California's emissions inventory for 2018 and 2019).

Comparative Life Cycle Evaluation of the Global Warming Potential (GWP) Impacts of Renewable Natural Gas Production Pathways

Renewable natural gas (RNG) sources are being considered in future energy strategy discussions as potential replacements for fossil natural gas (FNG). While today’s supply of RNG resources is insufficient to meet U.S. demands, there is significant interest in its viability to supplement and decarbonize the natural gas supply. However, the studies compare the life cycle global warming potential (GWP) of various RNG production pathways are lacking and focus mostly on a singular pathway. This effort is an attempt to close this gap and provide a comparison between the life cycle GWP of three major RNG pathways and the FNG pathway. The three RNG pathways evaluated are anaerobic digestion (AD), thermal gasification (TG), and power-to-gas (P2G) using various feedstocks. The functional unit is 1 MJ of compressed RNG ready for injection into the natural gas transmission network. The results show that RNG production is not always carbon neutral or negative. Depending on the pathway, the GWP impact of RNG production can range from −229 to 27 g CO2e/MJ compressed RNG, with AD of animal manure and AD of municipal solid waste being the least and the most impactful pathways, respectively, compared to the 10.1 g CO2e/MJ impact for compressed FNG.

Estimating water content of natural gas mixtures considering heavy hydrocarbons contribution using artificial neural networks

The accurate estimation of the water content of natural gas is the basis for proper equipment design in natural gas processing and transmission facilities. Methods for estimating the water content of natural gas have been reported based on pressure and temperature data, and the concentration of acid gases. This work aims to develop a predictive model based on artificial neural networks (ANN) to estimate the water content of natural gas, considering the contribution of heavier hydrocarbons than methane, commonly present in the rich gases, gas condensates, or liquefied petroleum gases. The novelty of the proposed model is the incorporation of natural gas richness (GPM) as an input parameter for calculating the water content of natural gas, in addition to temperature, pressure, and acid gas equivalent content. Experimental data from the literature is used in the ANN training and validation, with the help of the BigML machine learning platform to perform a multi-layer-feedforward neural network. The ANN performance showed the ability to accurately predict the water content for different gas mixtures (rich, lean, sweet, and sour gases). Comparisons with available models in the literature are performed, showing that the ANN model provides accurate estimations (AAD: < 10%).