Pipeline Wall Research Articles

Computational analysis of wax deposition in deep-water pipelines using nuclear techniques

Wax deposition in oil pipelines is a problem that affects flow assurance because it restricts production and, in more extreme cases, causes pipeline blockages. This problem occurs more frequently in offshore environments, where most of Brazil's reservoirs are located and where the ocean temperature at great depths is around 5°C. Detecting the wax layer on the inside walls of pipelines at an early stage avoids unscheduled stoppages and major economic losses. Among the various methods and techniques found in the literature for monitoring wax deposition, nuclear techniques are distinguished by the fact that their use does not interfere with the physical integrity of the pipeline, by the non-intrusive and indirect (non-contact) mode of operation and, therefore, does not affect the oil transportation process. This paper presents a computational model using the Monte Carlo N-Particle 6 (MCNP6) code and the gamma radiation transmission profiling technique to detect the presence of wax on the inner walls of pipelines used for deepwater oil transportation. The results of this study show that the model can detect the presence of up to 5% wax (in relation to the internal radius of the pipeline) with an accuracy of 7.4% in pipelines used in deep waters.

Reconstruction of the solid–liquid two-phase flow field in the pipeline based on limited pipeline wall information

Pipeline hydraulic transportation is the primary method for transporting deep-sea mineral resources and fossil fuels. Pipeline blockage often causes excessive pressure in the pipeline, leading to pipeline breakage or even cargo leakage, which severely impacts transportation safety and can easily trigger secondary disasters. Therefore, clarifying the global flow field within pipelines, such as particle distribution, is crucial for monitoring and controlling pipeline systems. This study uses a limited number of easily measurable pipeline wall sensor pressure values as inputs of deep learning models for flow field reconstruction, with the global flow field of solid–liquid two-phase flow in the three-dimensional pipeline as the output. Three model frameworks from existing studies are summarized, and their reconstruction effects are compared. Based on this, a new framework is proposed. It expands the low-dimensional sensor pressure values to the same size as the global flow field using a pseudo-decoder and then processes them through an autoencoder. The results indicate that the new framework achieves further accuracy improvements compared to the previous three frameworks, with R2 and mean squared error reaching 0.933 and 5.13 ×10−4, respectively. Additionally, the effects of the skip connection configuration of the model, dataset size, and model learning rate, as well as the number and arrangement of pressure sensors on reconstruction accuracy, are investigated. Finally, the transferability of the model is demonstrated by reconstructing the pressure and fluid velocity fields of the pipeline two-phase flow.

DEFINITION OF CERTAIN INDICATORS FOR CHOOSING A METHOD OF CORROSION PROTECTION FOR UNDERGROUND PIPELINES

Pipeline transportation of natural gas, oil, and petroleum products has become widely used both internationally and within Azerbaijan, as it is the most efficient and safe method of transportation. The durability and accident-free operation of pipelines directly depend on the effectiveness of their anti-corrosion protection. Therefore, the modernization of protection technologies is of critical importance. This study examines the main methods of pipeline anti-corrosion protection, considering the advantages and disadvantages of each. Calculations are provided for the pipeline wall thickness, anti-corrosion protection, and certain parameters of cathodic protection necessary to determine the most effective method for specific operating conditions. Keywords: corrosion, pipeline, sacrificial anode, passive protection, active protection.

Recent Patents on Pipeline Detection and Cleaning Electronic Devices

This paper provides an overview of the most recent advancements in pipeline inspection and cleaning technology over the past five years, drawing insights from patents and scholarly papers. It primarily focuses on three types of devices: long-distance pipeline inspection robots, small-diameter underground pipeline cleaning robots, and magnetic suction wall-climbing robots. A pipeline robot is a robot specifically designed to inspect, maintain and repair pipelines. With the continuous development and expansion of pipeline systems, today's pipelines have become an integral part of urban infrastructure. However, because pipelines are often located underground or in other hard-to-reach places, traditional inspection and maintenance methods become very difficult and expensive. Therefore, it is important to research and develop pipeline robots that can improve the safety, reliability and efficiency of pipeline systems by inspecting, cleaning, overhauling and even repairing pipelines. Devices need to be developed to clean the inner wall of pipelines from scale buildup and detect pipeline damage. This would improve conveyance efficiency and prolong the life of the pipeline. The pipeline cleaning robot cleans the pipeline scaling, removes pipeline deposits, and effectively solves the problem of low pipeline conveying efficiency or pipeline clogging; the pipeline inspection robot inspects the pipeline after the pipeline cleaning robot cleans the pipeline, detects whether there is any damage to the pipeline, and reduces the probability of pipeline conveying pipeline breakage. Pipeline robots can be transformed according to the parameters of the pipeline, adapting to different types of pipelines, and can effectively solve the problem of low pipeline conveying efficiency or pipeline clogging; pipeline inspection robots can detect the existence of pipeline damage in a timely manner, and can improve the reliability of pipeline conveying. The above technology improves the life span of pipes in pipeline transportation, improves the efficiency of pipeline transportation, solves the problem of pipeline clogging, and guarantees the reliability of pipeline transportation.

Accounting for melting properties in the multi-solid paraffin prediction model for analyzing well production at fields in the Republic of Kazakhstan

The deposition of paraffin on pipeline walls is a serious flow issue. leading to a reduction in oil production due to the decreased flow cross-sectional area. and in severe cases. to complete blockage. This problem also results in increased energy consumption and causes failure of surface equipment due to paraffin plugs. Traditional methods predict paraffin crystallization temperature by considering the impact of temperature on the solubility parameters of individual components in both liquid and solid phases as well as their molar volumes. The goal of this study is to improve the prediction of paraffin deposition in Kazakhstan crude oil by incorporating an evaluation of melting properties into the multi-solid (MS) body prediction model. The process of calculating and adjusting melting properties to enhance the accuracy of the MS model is described in detail. This approach helps to overcome the limitations faced by most existing models when adapting to different types of crude oil. In this study, the focus is on optimizing the multi-solid (MS) body prediction model for paraffin deposition by integrating the melting properties of crude oil components. The improvement of the MS model is crucial because paraffin deposition is a significant issue in Kazakhstan's oil fields, where the wide range of reservoir conditions can cause standard prediction models to fall short. By enhancing the accuracy of melting point calculations, the updated model can better predict the onset of paraffin crystallization and its deposition tendencies under varying pressure and temperature conditions. Keywords: melting properties; multi solid solution; petroleum; solid solution; paraffin deposition

Paraffin treatment of crude oil produced from the Central of Rong and Nam Rong - Doi Moi fields during transportation through uninsulated subsea pipelines

Due to being developed in the early stages, several major oil subsea pipelines in Vietsovpetro Joint Venture are not equipped with insulation systems, causing significant difficulties in transporting high-paraffin crude oil. Specifically, the lack of insulation leads to intensive heat loss through pipeline walls, resulting in paraffin deposition on the pipe surface. Additionally, the temperature drop significantly increases oil viscosity, leading to high pressure losses during transportation.This article analyses the difficulties in crude oil transportation through the uninsulated RP-1 → FSO-3 pipeline, the major route from Central of Rong, Nam Rong - Doi Moi fields to FSO-3 and presents the technical solutions that Vietsovpetro has researched and implemented to successfully resolve these problems.

ESTIMATION OF ELECTRICITY CONSUMPTION FOR WATER TRANSPORTATION IN PRESSURE PIPELINES AFTER THEIR REPAIR

The issues of using pipes made of different materials in water supply systems and the current situation with the technical condition of pressure pipeline transport are considered. It is noted that in order to ensure the standard service life of pipelines, it is necessary to carry out high-quality repair and restoration work using trenchless technologies and modern building materials, which include polymer pipes and flexible hoses. The object of research is a section of a dilapidated steel pipeline network of a certain thickness, diameter, depth and groundwater level above the tray. For the renovation of the pipeline, internal protective coatings are used, applied by dragging new pre-compressed polymer pipes and flexible polymer sleeves based on fiberglass. A description of trenchless technologies is presented, as well as automated programs that implement the tasks of determining the technological parameters (wall thickness of a polymer pipe and a polymer sleeve), hydraulic calculation of pressure losses depending on the degree of roughness of the pipeline walls, the inner diameter of a new two-layer pipe structure when passing a certain water flow, as well as the amount of electricity consumed for water transportation when appropriate wall thicknesses of protective coatings.

ASPECTS OF RELIABILITY, EFFICIENCY AND ENERGY SAVING OF GAS PIPELINES AND GAS SUPPLY SYSTEM EQUIPMENT

To ensure the safe operation of gas pipelines of the gas supply system it is necessary to solve the problems of timely detection and elimination of leaks, as well as to determine the volume of natural gas leaks. The most complicated case is the leakage from underground gas pipelines, as gas filtration into the ground, its spreading from the leakage place and accumulation in underground cavities are determined by many factors. Natural gas leaks, in addition to losses, may cause damage to buildings and structures, threat to human health and life due to burning or explosion of the gas-air mixture, financial and economic costs in case of gas shortages, and fines for consumers. Thus, the causes of failures are mainly corrosion wear and local defects of various origins on the walls of gas pipelines, which reduce the capacity of gas pipelines, as well as deteriorate the physical condition of the pipe metal - causing its fatigue under prolonged exposure to operational loads. The listed causes of failures, except for the last one, are well studied. The methods of local defects detection are developed, which will contribute to the improvement of the process of operation and repair and restoration technologies of gas pipelines. In contrast to the existing approaches, the approach presented in the article assumes improvement of the process of operation and repair and restoration technologies of gas distribution networks on the basis of local defects detection methods developed by the authors and improvement of their reliability taking into account the data on the actual technical condition and characteristics of each group of reliability indicators of elements of gas distribution networks.

Comparative Study of OLGA and LedaFlow Models for Mechanistic Predictions of Hydrate Transport Dynamics

Gas hydrate formation in pipelines transporting multiphase fluids from petroleum reservoirs can lead to the formation of blockages, representing a significant flow assurance challenge. Key issues caused by hydrates include substantial increases in the viscosity of mixed liquid phases and the deposition of hydrates on the pipeline wall. This study compares two existing transient multiphase flow simulators, OLGA and LedaFlow, in terms of their estimation of hydrate formation effects on multiphase flow. Here, we compared in detail the hydrate kinetic models, parameters used, and initial condition setup approaches that influence hydrate formation and affect multiphase flow properties. Based on the comparison between the simulation results, it was found that using both simulators with default setups may not lead to comparable results under certain conditions. Adjusting input parameters, such as the stoichiometric coefficient and hydrate formation enthalpy, is necessary in order to obtain equivalent results. Hydrate modules in both simulators have also been applied to a field case. With appropriate setup, OLGA and LedaFlow produce comparable results during steady-state simulations, which align with field observations. This work provides guidelines for setting up OLGA and LedaFlow simulation models to obtain equivalent results.

Reliability Analysis of the Collapse of Corroded Submarine Pipelines Subjected to Bending Moment

With the increasing development of oil exploration in the oceans, the demand for submarine pipelines has risen considerably, which implies significant environmental risks in the event of structural failure, resulting in oil leaks and consequent billion-dollar environmental damage. The integrity of these structures is primarily compromised by external pressures and bending moments, especially in areas of high curvature between platforms and extraction points. These bending moments, as identified in the investigations of Bjørset (2000), decrease the pipelines resistance to collapse due to the progressive ovalization of the sections, reducing the moment of inertia. Additionally, corrosion defects, which decrease the thickness of the pipeline walls, are prevalent and significantly impact the resistance to collapse, requiring precise evaluation in simulations (CABRAL, 2007). For the modeling of this mechanical phenomenon, the Finite Element Method (FEM) has shown promising results, being chosen to calculate the collapse pressures by combining the effects of bending moments and corrosion defects (MOTTA, 2020). However, the simulation process faces challenges due to uncertainties associated with measurement errors, equipment calibration, and manufacturing faults. These uncertainties are generally overlooked in traditional deterministic methods but can be addressed through reliability analyses that use statistical concepts to establish failure functions and assess failure probability, resulting in a more robust and reliable analysis (MOTTA, 2020). These analyses are rarely discussed in the existing literature, suggesting a need for more well-founded and detailed approaches. The results of this study, with the application of reliability techniques, are expected to provide safer insights into the influence of bending moments on the resistance of submarine pipelines. Furthermore, it is intended to compare deterministic equations with simulation results, proposing, if possible, adjustments to these equations to optimize the accuracy of the provided results.

Preparation and properties of Ni-SiO2 superhydrophobic coating by brush plating on inner wall of pipeline

Coal is easy to stay on the inner wall of the pipeline during transportation. In order to solve this problem, it is usually necessary to improve the hydrophobicity of the inner wall of the pipeline. In this study, 45 # steel, which is wear-resistant and has good machinability, is used as the matrix for coal pipeline. Ni-SiO2 composite coatings were prepared on the inner surface of 45 # steel pipelines using a novel brush plating tool, and the hydrophobicity of the coatings were evaluated. Firstly, a series of four-factor and three-level orthogonal tests were conducted to investigate the impact of brush plating working voltage (12V, 14V, 16V), nanoparticle concentration (1g/L, 2g/L, 3g/L), brush plating duration (2min, 3.5min, 5min), and bath temperature (25 ℃, 35 ℃, 45 ℃) on the hydrophobicity of the composite coating. Subsequently, optimum process parameters were determined. Then 1H, 1H, 2H, 2H- perfluorodecyltrimethoxysilane was used to modify the coating surface in order to further improve its hydrophobicity. Scanning electron microscope (SEM), energy spectrum analyzer (EDS), optical contact angle measuring instrument, white light interferometer, Vickers hardness tester, scratch tester, friction and wear meter and electrochemical workstation were used to evaluate the coating's related properties. The experimental results show that the Ni-SiO2 nano-composite coating has a higher angle (135°) when the operational voltage of brush plating is 14V, the amount of nanoparticles is 3g/L, the brush plating time is 2min, and the bath temperature is 35 ℃. The concentration of nanoparticles is the biggest factor affecting the hydrophobicity through orthogonal test analysis, so the control variable method is used to further study the influence of the concentration of nanoparticles on the comprehensive performance of the coating. It was found that with the increase of nanoparticle concentration, surface quality and comprehensive performance of the coating showed a trend of increasing first and then decreasing, and the surface of the coating was rougher when the nanoparticles were added at 4g/L, and the maximum porosity was 31.34%. At this time, the contact angle of the super hydrophobic coating has reached 150.1°, which has reached the super hydrophobicity, and the coating has good hardness, wear resistance and corrosion resistance.

Analysis of Resistance in Magnetic Flux Leakage (MFL) Detectors for Natural Gas Pipelines.

This study systematically explores the sources and influencing factors of resistance encountered by magnetic flux leakage (MFL) detectors in natural gas pipelines through a theoretical analysis, experimental investigation, and numerical simulation. The research methodology involves the development of a fluid-structure interaction model using ABAQUS 2023 finite element software, complemented by the design and implementation of a pull-testing platform for MFL detectors. This platform simulates detector operation under various interference conditions and quantifies the resulting frictional resistance. The findings reveal that the primary source of frictional resistance is the contact interaction between the MFL detector and the pipeline wall. Key factors influencing the magnitude of this resistance include the detector's mass, the structural design and materials of the sealing cups and support plates, as well as the surface roughness of the pipeline. Both experimental results and numerical simulations demonstrate a pronounced increase in frictional resistance with heightened interference levels. The theoretical model exhibits strong agreement with experimental data, though deviations are observed under conditions of severe interference. This study provides a detailed understanding of frictional resistance patterns under diverse structural and operational scenarios, offering both theoretical guidance and practical recommendations for the design of low-resistance MFL detectors.

A coupled model of zebra mussels and chlorine in collective pressurized irrigation networks

Zebra mussel infestation has become a serious problem affecting pressurized networks. Larvae settle in pipeline walls creating relevant obstructions to flow as they grow and develop shells. Oxidant injections in the stream are commonly used to control the infestation. A model is proposed for simulating the transportation, settlement and death of mussels in pressurized networks. This model is coupled to a solute transport, diffusion, and decay model of oxidant chemicals. During the analyzed irrigation campaigns, the larvae entry was monitored at various intervals. These data, showing high variability, were used as input to the model using different scenarios averaging and modifying the time distribution of larvae concentration. Simulations predicted similar mussel settlement patterns across all scenarios, suggesting that network morphology and total larval abundance primarily influence settlement distribution. We compared the effectiveness of continuous and intermittent oxidant applications. Continuous treatments were the most effective (up to 99%), but required up to 3.5 kg ha−1 of chlorine. Reasonable control could also be attained with short injections (1 to 3 h) just before the peak irrigation service discharge, leading to up to 93% of chlorine savings and reaching similar mortality rates. The model was also used to estimate the larvae and chlorine export to on-farm irrigation systems through hydrants and to evaluate strategies for mitigating the risks of on-farm infestation and environmental impact. The protection of on-farm irrigation systems required additional chlorine input. The model can be parametrized to simulate similar species in different types of pressurized networks, using different chemicals for treatment.

Control of Corrosion of Carbon Steel in Sea Water by Polyaniline/Epoxy-(graphene)-Based Double-Layered Smart Coatings

Carbon steel (CS) is the preferred construction material in most industries due to its cost-effectiveness and unique mechanical properties. However, CS is susceptible to corrosion, and it thus requires the application of proper corrosion control measures to lengthen its service life. With regards to the oil and gas industry, the pipelines used to transport the oil and gas from the offshore production well are exposed to two main forms of the corrosive environment: the saltwater that surrounds the pipeline's outer wall, and the acidic corrosive environment that attacks the inner pipeline wall, especially during the oil and gas reservoir service such as the acidizing procedure for enhancing oil recovery (EOR). The most common method employed to protect the pipeline's outer wall is the application of protective coatings. However, many of the currently used coatings are not effective for extended periods of service. Therefore, there is a need to develop coatings with improved anti-corrosive properties, which could have an extended service life and, if damaged/compromised, could counterbalance the damage by acting as smart coatings.To address the outer-wallcorrosion of carbon steel pipelines exposed to a simulated sea environment (3.5wt.% NaCl), two types of coatings were developed and characterized in our laboratory: (i) a composite double-layered anti-corrosive coating based on the inner electrically-conductive polyaniline (PANI) layer doped with graphene oxide (GO) synthesized electrochemically directly on the CS surface, and on the outer commercial epoxy coating, and (ii) a smart double-layered coating based on the inner PANI layer electrochemically formed on the CS surface and doped with sodium caprylate (SC) and sodium dodecyl sulphonate (SDS) as a corrosion inhibitor mixture, and the outer commercial epoxy coating.The use of the double-layer PANI/GO/epoxy coating resulted in significantly better long-term anti-corrosive properties in the protection of CS surface in 3.5 wt.% NaCl. The coating maintained its protection efficiency over two months of constant exposure to the corrosive electrolyte (Figure 1). The excellent corrosion protection properties of the coating were prescribed solely to the presence of the underlying PANI/GO layer, which represents a high barrier for the transport of hydrated corrosive ions to the CS surface, through the combined action of charge (passive oxide film formation), surface energy (hydrophobicity), and blocking mechanisms.The smart double-layered coating based on the inner PANI layer doped with SC+SDS and the outer epoxy layer yielded a hydrophobic surface and good adhesion to CS. When damaged to allow penetration of the corrosive electrolyte through it to reach the CS surface, it relatively quickly (within one day) recovered its anti-corrosive properties, as a consequence of the potential-driven release of SC+SDS from the PANI layer and its adsorption on the exposed CS surface, and it then continued to offer high corrosion protection during the remaining 29 days of exposure in aqueous 3.5 wt.% NaCl, in comparison with the undoped coating that failed rather quickly (within 4 hours), Figure 2. Figure 1

Analysis of the accuracy of the inverse marching method used to determine thermal stresses in cylindrical pressure components

This paper analyses the inverse marching method used to determine the thermal stresses on the inner surface of a thick-walled cylindrical element not weakened by holes in the transient state. The heat conduction problem was considered one-dimensional, i.e. it was assumed that heat is transferred only in the radial direction. The method is based on measuring the temperature inside the pipeline wall at a single point and assuming that the pipeline is thermally insulated. The paper undertook an evaluation of the influence of the measuring point's distance from the inner surface, the number of control volumes into which the inverted area was divided and the length of the time step on the accuracy of the calculated temper-ature, heat transfer coefficient and thermal stresses on the inner surface of the pressure element. Verification was performed by comparing the calculation results obtained from the direct analytical method perturbed by random errors with those obtained from the numerical inverse step method.

Simulation method for the operation of magnetic flowmeters

The issues of testing magnetic flowmeters for liquid metal and studies of their metrological characteristics are considered. The existing liquid metal pouring flowmeters are unsuitable for experimental studies of error components, therefore it is necessary to use simulation methods to simulate the operation of magnetic flowmeters. The tests require the liquid metal plants or methods that allow you to examine flowmeters without plants that can reproduce the flow rate in various operating modes. By analogy with the simulation method of water flowmeters research, a simulation method for modeling the operation of magnetic flow meters for liquid metals has been developed. The proposed method estimates the error of magnetic flowmeters in operation mode. The components of the measurement error of flowmeters caused by a violation of the geometry of the primary converter (the size and location of the electrodes, the design of the inductor coils), a change in the hydrodynamic regime, and the temperature dependence of the shunting effect of the pipeline wall are considered. A representation is obtained for the signal of the primary converter in the form of an integral over the inner surface of the pipe from the product of the radial component of the magnetic field and the surface weight function. The expression found can be interpreted as a magnetic flux through an induction coil located on the inner surface of the channel, the turns of which are drawn along the level lines of the surface weight function. This expression can be interpreted as a magnetic flux through an induction coil located on the inner surface of the channel, the coils of which are placed along the lines of the level of the surface weight function. If such a coil is inserted in the flowmeter channel, the time-integrated voltage induced in the coil will be proportional to the voltage generated between the electrodes of the flowmeter. Since the surface weight function depends on the geometry of the channel, the kinematic structure of the flow, the ratio of wall and liquid conductivities, therefore, the metrological characteristics of the flowmeter can be studied by the simulation method when each of the above factors changes individually or together. To do this, it is enough to make an induction coil taking into account the surface weight function that reflects any of the factors under study or their combination. Simulation methods for studying the dependences of magnetic flowmeter signals on the velocity distribution in the channel and the shunting effect of the pipeline wall are considered.

Numerical Simulation of Corrosive Flow in the Production End of Carbon Capture, Utilization, and Storage-Enhanced Oil Recovery Backflow Wastewater Pipeline

In a carbon capture, utilization, and storage-enhanced oil recovery (CCUS-EOR) system process, the high carbon dioxide content and high acid value of the fluid at the extraction end are treated at the wastewater treatment station and then flow through the transfer station of the gathering system. The reinjection system’s pipelines at the transfer station are prone to corrosion and leakage risks. A steady-state nonisothermal flow and corrosion model was established to examine this corrosive phenomenon by utilizing the principles of fluid dynamics and electrochemical corrosion. The study examined how flow velocity, temperature, pressure, and pH affected the pipeline’s corrosion. Simulation results showed flow velocity increased in specific places of both straight and curved pipeline sections. The velocity near the inner wall of curved portions was higher, making them more susceptible to cavitation damage. Faster flow rates, lower pH values, higher temperatures, and smaller pipeline diameters all contributed to increased corrosion on the inner walls of wastewater pipelines. The highest simulated corrosion rate was 8.3162 mm/a corresponding to the smallest pipeline diameter (100 mm), lowest pH (4), highest temperature (60°C), and highest flow rate (36.847 m/s). When designing the CCUS-EOR system, the nonmetallic pipeline should be given priority. If carbon steel metal pipelines are utilized, it is best to use larger-diameter materials in the engineering design. Additionally, procedures such as adding corrosion inhibitors to regulate pH values and lowering the temperature of wastewater conveyance might be explored to reduce corrosion on the pipeline’s inner walls.

Pulse eddy current testing of corrosion defects in pipelines with insulation layer based on U-shaped sensors

Abstract In response to the insufficient detection ability of CUI in pipelines, based on U-shaped sensors, combined with the wide spectrum and non-contact characteristics of pulse eddy current detection technology, the area and depth of corrosion defects on the outer wall of pipelines can be effectively detected without removing the insulation. Simulation and experimental research are conducted on the outer wall defects of carbon steel test tubes with insulation layers. The simulation results show that the excitation magnetic field generated by the U-shaped sensor can effectively penetrate the inner wall of the pipeline, and the two signal-receiving coils of the U-shaped sensor will generate significant characteristic signals when passing through defects. The detection voltage position curve is obtained by applying the voltage distribution analysis method, and the characteristic signal length is the defect length. The experimental results show that when the detection sensor passes through and leaves the defect, the detection voltage distribution curve will generate a significant voltage drop characteristic signal, and the distance between the measurement points is consistent with the length of the defect. The experimental results are highly consistent with the simulation results.

Study of hydraulic transport characteristics and erosion wear of twisted four-lobed pipe based on CFD-DEM

Pipeline hydraulic transportation is extensively utilized across diverse sectors, with enhancing the performance of pipeline hydrodynamic transport and minimizing erosion wear on the pipeline walls being essential for ensuring the stability of pipeline operations. This paper introduces a methodology for the hydraulic transport of a twisted four-lobed pipe, employing a numerical and erosion model developed through the CFD-DEM (computational fluid dynamics and discrete element method) coupling approach. An experimental circulating flow platform is constructed for validation purposes. The performance of the pipe is assessed by analyzing key indices including fluid velocity, pressure drop, particle trajectory, and erosion wear. The results indicate that twisted four-lobed pipe enhances fluid flow rates, facilitating particle discharge and mitigating accumulation, with reduced wear compared to the twin twist triangle spiral pipe. The analysis of structural parameters’ impact on hydraulic conveyance is also presented. These findings offer theoretical insights for optimizing pipeline performance in hydraulic conveyance while minimizing wear.

Assessment of the influence of glycol and alcohol on the morphology and protective properties of iron carbonate in carbon dioxide corrosion of gas pipelines

The potential effect of hydrate formation inhibitors (glycols, alcohols) — components of the liquid phase of gas pipeline operating media — on carbon dioxide corrosion during the transport of aggressive gas has not been sufficiently studied. The paper presents the results of a study of the corrosive effect of glycol (alcohol) present in the liquid phase on the composition and properties of corrosion products on steel when modeling the main aggressive factors under conditions of transport of CO2-containing gas. On a corrosion stand, the aggressive conditions of alternating wetting of gas pipeline walls with water were reproduced. The fluid circulation characteristic of a partially filled pipeline can have an effect on preventing the formation or destruction of films of corrosion products (iron carbonate, siderite) on the steel surface. In places of cracking and peeling of siderite formed in the presence of CO2, conditions will be created for the formation of general and local corrosion damage. During simulation tests, monoethylene glycol and isopropanol, as well as their aqueous solutions of different concentrations, were used. For the first time, data on the formation and composition of non-stoichiometric siderite in water-glycol and water-alcohol media at CO2 partial pressures and temperature were obtained. By processing diffraction patterns obtained by X-ray diffraction, the degree of substitution of iron ions in non-stoichiometric siderites by other cations was determined. The dependence of the degree of substitution on the concentration of alcohol (glycol) in their aqueous solutions was analyzed. It was revealed that with an increase in glycol concentration, a decrease in the rate of local corrosion is observed. With a high glycol content, internal corrosion is completely suppressed in the presence of CO2. It has been established that in aqueous-alcoholic media at elevated temperatures, local carbon dioxide corrosion does not occur. This is apparently due to the uneven distribution of water and alcohol in the mixture. The results obtained can be used in assessing internal carbon dioxide corrosion in the presence of glycol (alcohol), used at gas facilities as an inhibitor of hydrate formation.