Pipeline Transportation Research Articles

Computational modeling of localized corrosion in steel pipelines supported by composite sleeves

Pitting corrosion is a worrying phenomenon in the oil industry representing a major threat that can lead to the reduction of the structural integrity of pipeline transportation networks. To prevent this corrosion risk, active cathodic protection with a potential maintained at – 850 mV Cu/CuSO4 is used as a coating protection system based on bituminous binders to isolate the steel from the corrosive soil environment in hydrocarbon transportation pipelines. In this work, we examine the clock spring repair method by applying composite paths including a numerical simulation on corroded tubes using ANSYS software. The approach involves analyzing the structure under three scenarios: without defects, after the introduction of elliptical simulated corrosion pits, and following repair with multilayer reinforcement using a composite sleeve. The results indicate that the stress distribution varies across each scenario. In the case of a structure with parabolic corrosion defects, the Von Mises stresses are unevenly distributed. The defect exhibits a peak stress that could lead to the propagation of corrosion pits, necessitating repair. Conversely, in the scenario where the corroded structure is reinforced with a composite sleeve, the maximum Von Mises stress is decreased to levels comparable to those of an uncorroded pipe, demonstrating the necessity and effectiveness of using composite sleeve reinforcement.

Effects of spherical, disk-like and lamellar nanocomposite particles on cold flow behaviors of waxy crude oil

Wax precipitation and deposition are challenging hurdles in pipeline transportation of waxy crude oil. This study focuses on transforming SiO2, Laponite, and montmorillonite particles into hydrophobic particles through polymer grafting. Chemical structure analysis and grafting ratio calculation were performed. Through thermogravimetric analyzer (TGA) test, Laponite showed the highest grafting ratio. The effects of adding nanocomposites, TDA-2024-22, and commercial pour point depressants on the rheological behavior and wax crystallization behavior of African crude oil were compared. Addition of the nanocomposite PDA-22@SiO2 to crude oil, reduced the viscosity by 85.6% at 20 °C and the thixotropy by 60.2%. Wax crystal size decreased in the order of PDA-22@SiO2, PDA-22@Laponite, KS-10, TDA2024-22, and PDA-22@MMT. The pour point decreased by 6 °C with PDA-22@ SiO2 particles but only 3 °C with Laponite and montmorillonite composites. Spherical nanocomposites are promising flow improvers for waxy crude oil.

Leakage Failure Analysis of Some Gas Transportation Pipeline Girth Weld

Leakage Failure Analysis of Some Gas Transportation Pipeline Girth Weld

Pressure and Temperature Prediction of Oil Pipeline Networks Based on a Mechanism-Data Hybrid Driven Method

To ensure the operational safety of oil transportation stations, it is crucial to predict the impact of pressure and temperature before crude oil enters the pipeline network. Accurate predictions enable the assessment of the pipeline’s load-bearing capacity and the prevention of potential safety incidents. Most existing studies primarily focus on describing and modeling the mechanisms of the oil flow process. However, monitoring data can be skewed by factors such as instrument aging and pipeline friction, leading to inaccurate predictions when relying solely on mechanistic or data-driven approaches. To address these limitations, this paper proposes a Temporal-Spatial Three-stream Temporal Convolutional Network (TS-TTCN) model that integrates mechanistic knowledge with data-driven methods. Building upon Temporal Convolutional Networks (TCN), the TS-TTCN model synthesizes mechanistic insights into the oil transport process to establish a hybrid driving mechanism. In the temporal dimension, it incorporates real-time operating parameters and applies temporal convolution techniques to capture the time-series characteristics of the oil transportation pipeline network. In the spatial dimension, it constructs a directed topological map based on the pipeline network’s node structure to characterize spatial features. Data analysis and experimental results show that the Three-stream Temporal Convolutional Network (TTCN) model, which uses a Tanh activation function, achieves an error rate below 5%. By analyzing and validating real-time data from the Dongying oil transportation station, the proposed hybrid model proves to be more stable, reliable, and accurate under varying operating conditions.

Magnetically recoverable nanoparticle organic hybrid materials as kinetic hydrate inhibitors

Gas hydrates pose significant risks in the oil and gas industry because of their tendency to form blockages in transportation pipelines under low-temperature and high-pressure conditions. Conventional thermodynamic hydrate inhibitors require high dosages, with associated substantial costs and environmental concerns. Kinetic hydrate inhibitors (KHIs), which operate at much lower dosages, offer a more sustainable solution but are often limited by environmental compatibility and recovery problems. In this study, we introduce a novel class of magnetically recoverable KHIs utilizing nanoparticle organic hybrid materials (NOHMs), named NOHM-I-PNIPAM, featuring a tunable Fe3O4 core-SiO2 shell structure with poly(N-isopropylacrylamide) (PNIPAM) as the organic component. The chemical properties of NOHM-I-PNIPAM were characterized using TEM, FT-IR, and XPS. The hydrate kinetic inhibition performance was evaluated with a CH4 (90 %) + C2H6 (7 %) + C3H8 (3 %). Various grafting densities of PNIPAM on NOHMs and weight fractions of NOHM-I-PNIPAM were used to explore NOHM-I-PNIPAM’s role in the formation kinetics of natural gas hydrates under different cooling rates. Notably, the NOHM-I-PNIPAM (1.0), when utilized at a 2 wt% dosage, exhibited the most effective inhibition performance in terms of the onset temperature of CH4 (90 %) + C2H6 (7 %) + C3H8 (3 %) hydrate. Considering the effective concentration of PNIPAM in NOHM-I-PNIPAM, the inhibition performance was found to be comparable to that of conventional PNIPAM. Results showed that NOHM-I-PNIPAM is a promising KHI due to its combined properties of magnetic separation and comparable kinetic inhibition performance. Experimentally, NOHM-I-PNIPAM demonstrated stability over long-term cycles and was effectively magnetically separated. Hence, we believe that this work can provide valuable insights into the potential of NOHMs as recoverable and reusable KHIs for industrial applications for flow assurance.

Integrity and Safety Management Challenges of Supercritical CO2 Pipeline Transportation at Offshore Platforms

Integrity and Safety Management Challenges of Supercritical CO2 Pipeline Transportation at Offshore Platforms

The durability of viscosity reduction of magnetically treated waxy crude oil

Magnetic treatment is a method for improving the cold flowability of waxy oils. Previous studies have predominantly focused on the viscosity reduction resulted from the treatment, with the durability of the magnetic effect neglected, which is crucial for pipeline transportation of the treated crude oil. Therefore, this study focuses on the durability and its mechanism of the magnetic effect of a waxy crude oil under static, low shear, and high shear conditions. A viscosity reduction of 15.7% was achieved under the magnetic treatment condition of the magnetic treatment temperature at 52 °C, magnetic field strength at 0.1 T, and a duration of 1 min. However, the magnetic effect gradually diminished with time elapsing and disappeared in 9 h under static conditions. Shear was found to be beneficial to the preservation of the effect, and a correlation between the viscosity of the sheared treated-oil and the energy dissipation of the shear was found. Microscopic observations, impedance measurements, and x-ray diffraction analysis revealed that exposure to a magnetic field might disperse the charged particles, i.e., resins and asphaltenes, in the crude oil, facilitating their adsorption on the wax particle surfaces, thus enhancing electrostatic repulsion among wax particles and resulting in viscosity reduction. The desorption of the adsorbed resins and asphaltenes from the wax particles and reaggregation lead to the gradual diminishment of the viscosity reduction. Shear might inhibit this reaggregation and thus contribute to the durability of the viscosity reduction.

Analysis of wax deposition phase change law and main influencing factors in oil-water mixed transportation pipeline under unsteady working conditions

Analysis of wax deposition phase change law and main influencing factors in oil-water mixed transportation pipeline under unsteady working conditions

Enhancing safety in hydrogen storage: Understanding the dynamic process in hydrogen-methane mixtures during the pressurized leakage

Using natural gas pipelines for hydrogen-doped transportation represents a cost-effective solution for large-scale and long-distance hydrogen transport. However, concerns have been raised regarding the potential for leakage under high-pressure conditions, which could result in the spontaneous combustion of the leaking hydrogen. It is, therefore, imperative to understand the gas dynamics involved in methane-hydrogen mixtures during high-pressure leaks to ensure the safety of hydrogen storage. In the present work, the release process and the spontaneous ignition of hydrogen/methane mixtures with a hydrogen blending ratio from 0.1 to 1.0 from pressurized storage containers (20 MPa) have been numerically studied upon validated models. The findings indicate that spontaneous ignition occurs in the mixtures with any hydrogen blending ratios under the releasing pressure of 20 MPa, but the methane component is not involved in the initial combustion if the hydrogen blending ratio is less than 0.5. As the hydrogen blending ratio increases, more combustible components are involved in the initial ignition, and the location of the initial ignition turns closer to the leakage port. Meanwhile, as the hydrogen blending ratio rises from 0.1 to 1.0, the shockwave propagation is accelerated with the moment the shockwave first reflects is advanced from 58 to 60 μs to 22–24 μs, and the maximum temperature in the early leakage will exceed 3000 K. Furthermore, a higher hydrogen blending ratio leads to a more rapid pressure rise in the external space (reaching peak pressure at 191 μs for pure hydrogen) and forming a Mach disk structure with higher Mach numbers (around 7). These findings provide critical insights for understanding the combustion behavior of hydrogen/methane mixtures in high-pressure pipelines and offer valuable guidance for developing safety protocols and infrastructure designs.

Progress in Corrosion Protection Research for Supercritical CO2 Transportation Pipelines

Carbon Capture, Utilization, and Storage (CCUS) technology is an emergent field with the potential for substantial CO2 emissions reduction, enabling low-carbon utilization of fossil fuels. It is widely regarded as a critical technology for combating global climate change and controlling greenhouse gas emissions. According to recent studies, China has identified CCUS as a key emissions reduction technology in climate change response and carbon neutrality objectives. Within this framework, supercritical CO2 (SC-CO2) transport pipelines are an essential means for efficient and safe transportation of CO2. Corrosion protection of pipelines enhances the efficiency and safety of CCUS technology and supports broader implementation and application. This paper reviews the current research on corrosion protection for SC-CO2 transport pipelines, discusses effect factors, compares various corrosion protection strategies, and analyzes the challenges in corrosion protection of SC-CO2 transport pipelines. It concludes with a perspective on future research and development directions in this field. This paper is dedicated to providing new research strategies for pipeline corrosion protection in CCUS technology in the future, and providing technical support for pipeline corrosion protection in CCUS industrial applications.

Development and Experimental Study of an Experimental Setup for an Online Vibrating Tube Liquid Densitometer

Density is a crucial parameter for quantitatively describing the physical properties of liquids. It serves as an important indicator for scientific research, production process control, pipeline transportation, and other aspects. In oil pipeline transportation and raw material processing, the real-time online measurement of liquid density is of great significance. This paper analyzes the working principle of an online vibrating tube densitometer and derives the fitting equation for temperature, pressure, and density; it also conducts experiments with an online vibrating tube liquid densitometer and establishes a traceability chain for the experimental device. The experimental setup includes a desktop densitometer system, a multi-temperature field constant-temperature stirring system, a walk-in constant-temperature box, an automatic blowing system, and a frequency acquisition and calculation system. The uncertainty of the device’s evaluation is U = 0.08 kg/m3, k = 2. We built a set of pressure-density static test systems, statically testing the online vibrating tube’s liquid-density meter vibration frequency at different pressures; the whole set of systems can be used to assess the specific density, temperature, and pressure range of online vibrating tube liquid density meters in the experimental research to derive the standard temperature. Through the experimental research, we can accurately derive the fitting coefficients under the standard temperature, specific temperature, and pressure of online vibrating tube liquid densitometers, and calculate the fitting error of online vibrating tube liquid densitometers under different temperatures and pressures within the experimental range through fitting equations and coefficients, so as to realize the practical application of online vibrating tube liquid densitometers in engineering by utilizing straight-tube-type and curved-type online vibrating tube densitometers. A preliminary study was conducted on the effects of different densities, temperatures, and pressures on the vibrating tube system’s vibration cycle. The fit coefficient and error were calculated, and the experimental results were compared to the theoretical analysis to confirm the device’s conformity. The study verified the device’s scientific and reasonable design, and demonstrated that it is feasible to use the device for follow-up research. Using this device in subsequent experiments can verify the effects of viscosity, inlet, installation, and other factors on the online vibrating tube liquid densitometer’s metrological performance. Further experimental research on the pressure–frequency–density test system and the establishment of a wide range of temperatures and pressures within the pressure standard density test system are needed to achieve a wide range of temperatures and pressures under the standard density test.

A novel optimization framework for natural gas transportation pipeline networks based on deep reinforcement learning

Natural gas is an emerging and reliable energy source in transition to a low-carbon economy. The natural gas transportation pipeline network systems are crucial when transporting natural gas from the production endpoints to processing or consuming endpoints. Optimizing the operational efficiency of compressor stations within pipeline networks is an effective way to reduce energy consumption and carbon emissions during transportation. This paper proposes an optimization framework for natural gas transportation pipeline networks based on deep reinforcement learning (DRL). The mathematical simulation model is derived from mass balance, hydrodynamics principles of gas flow, and compressor characteristics. The optimization control problem in steady state is formulated into a one-step Markov decision process (MDP) and solved by DRL. The decision variables are selected as the discharge ratio of each compressor. By the comprehensive comparison with dynamic programming (DP) and genetic algorithm (GA) in three typical element topologies (a linear topology with gun-barrel structure, a linear topology with branch structure, and a tree topology), the proposed method can obtain 4.60% lower power consumption than GA, and the time consumption is reduced by 97.5% compared with DP. The proposed framework could be further utilized for future large-scale network optimization practices.

Transportation of Liquefied Natural Gas (LNG) via Long-Distance Low-Temperature Pipeline and Cascade Utilization of Cold Energy

In addition to methane, liquefied natural gas (LNG) typically contains valuable light hydrocarbons such as ethane, propane, and butane. Establishing LNG receiving stations for imported LNG can effectively alleviate regional energy supply-demand conflicts, optimize energy consumption structures, promote sustainable regional economic development, and improve ecological environments. The technology for long-distance low-temperature pipeline transportation of LNG facilitates the efficient transfer and cascading utilization of the cold energy contained in LNG, allowing for deep coupling with cold networks and natural gas pipelines, thereby promoting the integrated development of LNG, cold energy, and natural gas transportation. This paper systematically summarizes the current status of LNG long-distance low-temperature pipeline transportation technology, cold energy cascading utilization technology, pipeline regulation technology, and multi-network integration technology. It analyzes the key challenges these technologies face under new strategies and looks ahead to future development trends, aiming to provide scientific insights and directions for the application of LNG long-distance low-temperature transportation and multi-network integration in China.

Hydrodynamic analysis of core annular flow with a viscoplastic lubricant

Core annular flow (CAF) with viscoplastic lubrication (VPL) is an attractive proposition for pipeline transportation of high viscous oil, slurries and suspensions. Past studies have performed stability analysis to show that the unyielded zone at the liquid-liquid interface stabilizes CAF by suppressing interfacial instabilities. However, an in-depth investigation of the flow hydrodynamics and the conditions which reduce the pumping power within stable CAF range using VPL has not been reported till date. Moreover, most of the studies have considered a Bingham Plastic liquid in the annulus. Only a single study (Usha & Sahu, 2019) is reported with Herschel-Bulkley (HB) liquid in the annulus that considers the entire annulus to be in the shear zone. Another experimental study (Huen et al., 2007) has demonstrated stable core annular flow with a shear thinning core and a HB annulus. In the present work, we analyze viscoplastically lubricated CAF for a Newtonian core where the yield stress annular liquid is described by the generalized HB model. The simplified analysis can predict CAF stability and is further explored to (i) assess the efficacy of VPL for stable energy-efficient oil transportation, and (ii) enhanced throughput without clogging during suspension transportation. The analysis, validated against data from literature, unravels the influence of rheological properties on flow hydrodynamics. We note that an annular liquid with low flow behavior index, n and yield stress, τy lowers pumping power, but the yield stress should be sufficient to form a plug zone at the interface for suppressing instabilities and stabilizing CAF. For viscous oil, a phase diagram in dimensionless coordinates (Reynolds number of the oil core and Herschel-Bulkley number of the annular liquid, both expressed at the inlet conditions) suggests the range of operation where an available HB liquid can serve as an effective annular lubricant for energy-efficient transportation.

Integrated Planning Model for Carbon Capture and Storage Systems Considering CO2 Pipeline Transportation Properties

Integrated Planning Model for Carbon Capture and Storage Systems Considering CO₂ Pipeline Transportation Properties

Local Stability Analysis of a Composite Corrugated Steel Plate Pipe-Arch in Soil

The straight part of the corrugated steel plate (CSP) pipe-arch structure in soil may cause local buckling instability due to insufficient load-bearing capacity. Recently, composite CSP pipe-arch has been widely utilized to enhance structural stability, and their stability needs to be thoroughly investigated. This paper studies the local buckling stability problem of the straight part of composite CSP pipe-arch in soil by simplifying the soil support and introducing the inter-layer bonding effect. Based on elastic stability theory, a theoretical mechanical model of composite CSP pipe-arch was proposed. The Rayleigh–Ritz method and the semi-combined composite structure stiffness approximation were used to derive the critical buckling conditions for the straight part of the composite CSP pipe-arch. Through numerical calculation and influencing factors analysis, it is concluded that the critical buckling load of the straight part of the composite CSP pipe-arch structure is affected by the elastic modulus, thickness, Poisson’s ratio, rotational restraint stiffness and side length of the straight part of the material. In particular, it is found that as the inter-layer bonding coefficient increases, the critical buckling load is improved, while the critical buckling wave number is mainly influenced by the width of the straight part, elastic modulus, and inter-layer bonding coefficient. Additionally, we discussed the coupling effect of several key parameters on the stability of the structure. The results of this study offer theoretical foundations and guidance for the application of composite CSP pipe-arch in soil engineering, such as culverts, tunnels, and pipeline transportation.

Techno-Economic Feasibility Analysis of Post-Combustion Carbon Capture in an NGCC Power Plant in Uzbekistan

As natural gas-fired combined cycle (NGCC) power plants continue to constitute a crucial part of the global energy landscape, their carbon dioxide (CO2) emissions pose a significant challenge to climate goals. This paper evaluates the feasibility of implementing post-combustion carbon capture, storage, and utilization (CCSU) technologies in NGCC power plants for end-of-pipe decarbonization in Uzbekistan. This study simulates and models a 450 MW NGCC power plant block, a first-generation, technically proven solvent—MEA-based CO2 absorption plant—and CO2 compression and pipeline transportation to nearby oil reservoirs to evaluate the technical, economic, and environmental aspects of CCSU integration. Parametric sensitivity analysis is employed to minimize energy consumption in the regeneration process. The economic analysis evaluates the levelized cost of electricity (LCOE) on the basis of capital expenses (CAPEX) and operational expenses (OPEX). The results indicate that CCSU integration can significantly reduce CO2 emissions by more than 1.05 million tonnes annually at a 90% capture rate, although it impacts plant efficiency, which decreases from 55.8% to 46.8% because of the significant amount of low-pressure steam extraction for solvent regeneration at 3.97 GJ/tonne CO2 and multi-stage CO2 compression for pipeline transportation and subsequent storage. Moreover, the CO2 capture, compression, and transportation costs are almost 61 USD per tonne, with an equivalent LCOE increase of approximately 45% from the base case. This paper concludes that while CCSU integration offers a promising path for the decarbonization of NGCC plants in Uzbekistan in the near- and mid-term, its implementation requires massive investments due to the large scale of these plants.

Research progress of hydrogen blocking coatings

In the context of carbon peak and carbon neutrality, the use of clean energy has become the focus of attention. Hydrogen energy as the most potential secondary energy has a very important position in various fields, so the storage and transport of hydrogen energy is one of our most important concerns. Long distance pipeline is regarded as an effective means to transport hydrogen, but the high pressure hydrogen environment is easy to cause hydrogen embrittleness and other problems in the pipeline, which seriously threatens the safety of pipeline transportation. Hydrogen blocking coatings are one of the most effective ways to solve such problems. In this paper, the research results in recent years are reviewed and summarized. The article points out the hydrogen barrier mechanism, advantages and disadvantages of various types of hydrogen barrier coatings, the current status of research, as well as future research focus and development trend.

Numerical study on drag reduction and heat collection efficiency of oil based on solar concentrating system

Traditional onshore crude oil storage and transportation consumes a lot of energy. In this paper, a concentrating type of high-temperature crude oil transportation pipeline heating system is proposed, which uses concentrators to collect and focus sunlight on the pipeline. The high-temperature oil flows through the heat exchanger at the end of the pipeline, where it exchanges heat with water to store and recover heat for utilization in the heat collector. The temperature rise is significant and the uniformity improves as oil extends through the pipeline under various multiples of solar radiation achieved with concentrators. The inlet rate of oil is a negative factor affecting the outlet temperature. Compared to non-concentrated light, the friction coefficient and viscosity of oil are reduced, resulting in a more effective drag reduction effect. To validate the accuracy of simulation results and compare them with theoretical calculations, ensuring that the margin of error is within 8.5%. The type of concentrators, laying distance of the concentrators below the pipeline, concentration ratio (CR), and the inlet rate can be adjusted based on climatic conditions and required oil temperature. This paper is of great significance for reducing energy consumption in long-distance oil transportation and realizing the energy transition.

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.