Main Gas Pipelines Research Articles

ENVIRONMENTAL ASPECTS OF DESIGNING TURBOCOMPRESSOR UNITS OF COMPRESSOR STATIONS OF MAIN GAS PIPELINES

The article examines the environmental aspects of creating turbo-compressor units for compressor stations of main gas pipelines. The aim of the study is to identify and analyze the main sources of environmental pollution arising from the operation of turbo-compressor units, as well as to analyze modern technical solutions aimed at reducing their negative impact on the environment. This goal is achieved through an analysis of the operational processes of turbo-compressor units, a review of literature sources and applicable regulations, as well as the systematization of many years of experience gained at JSC “SMNPO-Engineering” (Sumy, Ukraine) in the design and testing of similar equipment. The most important results of the work are as follows: sources of chemical, acoustic, and thermal pollution generated during the operation of turbo-compressor units with gas turbine drives and centrifugal compressors have been identified; a conclusion has been drawn about the priority of developing dry fuel combustion methods to reduce emissions of pollutants. It is noted that the application of catalytic exhaust gas purification systems is advisable for modernizing existing compressor stations to ensure compliance with environmental requirements without replacing or significantly reworking engine designs. Using a 16 MW gas turbine compressor unit as an example, an assessment of thermal pollution in the environment has been carried out. It has been concluded that reducing thermal pollution can be achieved by increasing the energy efficiency of turbo-compressor units, particularly through the application of complex working cycles of the drive, utilizing waste heat from exhaust gases, and creating energy technology complexes based on compressor stations of main gas pipelines for the production of electricity, heat, and cooling. The results of this work can be used in the development of environmentally more efficient turbo-compressor units, which is especially relevant in the context of global climate change and increasing requirements of international environmental regulations. Moreover, increasing the energy efficiency of turbo-compressor units will not only reduce environmental pollution but also lower energy consumption and improve the cost-effectiveness of gas transportation.

ANALYSIS OF THE CAUSES OF ACCIDENTS IN THE OIL AND GAS INDUSTRY

In the modern world, the oil and gas industry plays a key role in ensuring the energy security of countries. An important problem of this industry is the high level of accidents on main pipelines. The importance of issues of ensuring the safety of production processes and working conditions of personnel is obvious: accidents that occur at enterprises can paralyze work for a long time, attracting the attention of the media and regulatory authorities, causing not only financial but also significant image damage. In connection with the above, the analysis and statistical study of accidents in this area have become relevant in recent years. Occupational safety measures include risk assessment at workplaces, briefings, medical examinations, provision of personnel with personal protective equipment, special assessment of workplaces, occupational safety days, etc. In order to restore the technical and economic indicators of the oil and gas industry, increase reliability and trouble-free operation, complexes of measures are carried out to repair, reconstruct and modernize the components of the main gas pipeline. Ensuring industrial safety during repair work depends on both the reliability of the process equipment and the reliability of the personnel, since a significant number of accidents and incidents occur due to reasons related to the influence of the human factor. Many studies have been devoted to the problem of management in the field of labor protection and ensuring safety at work. Despite the significant number of works, a practical lack of developments on the issues of managing the processes of ensuring safety and labor protection at enterprises in the oil and gas industry has been discovered, which indicates the need for a more in-depth study of this topic.

Negative impact of vibration on process pipelines of a compressor station with electrically driven gas pumping units

Relevance. In gas industry, the amount of equipment that has outlived its intended service life is increasing every year. In accordance with the law “On Industrial Safety of Hazardous Production Facilities,” compressor stations are dangerous objects, the reliable operation of which largely determines the condition of main gas pipelines. Technological pipelines of a compressor station are important objects of this system. They are subject to strict requirements due to the action of static and dynamic loads on them. Reliability of compressor stations is based on the results of a study of the condition of the object and the main factors affecting increased wear of equipment. The solution to wear problem is timely monitoring of equipment, in particular level measurement and determining the causes of pipeline vibrations using vibration diagnostics methods, and frequency and modal analysis methods. Aim. To study the causes of increased dynamic loads on the technological piping that arise during the operation of electric and gas pumping units at a compressor station using vibration monitoring methods. Methods. Vibration monitoring methods to analyze the causes of increased vibration values in the process piping of a compressor station with an electric gas pumping unit. Results and conclusions. The authors have measured vibration in a wide frequency band and assessed the technological condition of the main equipment of the compressor station with EGPA-6.3/8200-56/1.44-R based on the regulatory documentation STO Gazprom 2-2.3-324-2009. The main frequencies of the root-mean-square value of the vibration velocity, at which the highest vibration values were observed, were identified, and a modal analysis was performed using ANSYS software. Based on the results of natural studies and modal analysis, it was concluded about the occurrence of resonant high-frequency oscillations, multiple of the rotor rotation frequency.

Optimization of combined algorithms control electric drives of installations natural gas cooling

The relevance of the problem of reducing energy consumption by electric drives of natural gas cooling units at compressor stations of main gas pipelines is substantiated. The possibility of solving this problem with the help of a combined control system containing two groups of gas air cooling devices is considered: with continuously and discretely controlled speed of electric fan drives. An algorithm for control that is optimal according to the criterion of maximum power savings is obtained, taking into account the peculiarities of temperature distribution along the length of the heat exchanger of the cooling apparatus. It is shown that under conditions of restrictions on control actions, the optimal control algorithm consists of several intervals. Relationships were obtained for calculating the optimal speed of electric fan drives of the first group, the number of switched on electric fan drives of devices of the second group, and power savings at individual control intervals. The influence of the number of devices with continuous fan speed control on the amount of power savings was assessed. The possibility of using a simplified methodology for assessing energy savings based on average indicators of the operating mode of a cooling installation is discussed.

Resistance of the welded joint of X70 steel for main gas pipelines against corrosion-mechanical cracking under cathodic polarization in near-neutral pH solutions

ABSTRACT Resistance of welded joint of X70 steel welded using Sv-08G1NMA and OK 10-74 flux wire against stress-corrosion cracking in near-neutral pH solution NS4 was investigated by slow-strain rate method, voltammetry, optical and scanning electron microscopy, electrolytic permeation of hydrogen. It was established that the stress-corrosion cracking of welded joint occurs through the base metal in the range of potentials more positive than −0.921 V by the anodic dissolution mechanism, more negative than −1.050 V is consistent with a hydrogen embrittlement mechanism, and in the potentials' range from −0.921 V to −1.050 V – both by the anodic dissolution and hydrogen embrittlement mechanism. The susceptibility to stress-corrosion cracking coefficient KS increases with the polarization potential shift −0.750 V → −0.950 V → −1.050 V as follows: for the welded joint – 1.1 → 1.16 → 1.35, for X70 steel as 1.0 → 1.12 → 1.0.

TO THE ISSUE OF SOIL VARIOUS TYPES INFLUENCE ON PIPELINE LONGITUDINAL MOVEMENT

Achieving and maintaining the required reliability of the linear part of the main gas pipelines is of great importance. Emergency destruction usually leads to large gas leaks into the atmosphere and undersupply to consumers, significant costs for the restoration of main gas pipelines. The rise in cost of repair work on main gas pipelines directly depends on the difficult conditions of the route. Special technical solutions are to be used for achieving the necessary stability and reliability of pipelines on low-bearing soils. Thus, on operating gas pipelines at variable temperatures of the transported product, their longitudinal movements occur, resulting in longitudinal forces appearance and correspondingly in increase of gas pipeline stress state and their possible destruction. The significant period of time of increase in gas pipeline movements indicates that these changes in pipeline position occur due to the rheological properties of soils. An analysis of the stress state of such sections of gas pipelines is necessary to assess their operational reliability and, as a result, the timing and methods of repair. This article discusses the maximum values of longitudinal displacements of a pipeline laid in various soils and the deflection values corresponding to these models for potentially dangerous sections.

INNOVATIVE INSULATING MATERIAL IN THE ASPECT OF ENSURING THE SAFETY OF HYDROCARBON TRANSPORTATION

Ensuring continuous and safe operation of the main oil and gas pipelines is a critical aspect for preserving the environment and efficient use of hydrocarbon resources. More than half of accidents on trunk gas pipelines occur due to corrosion wear of the metal caused by insufficient protection of the insulation coating. The consequences of such incidents have a devastating impact on the environment and human lives: spilled oil and oil products pollute the soil, and leaking gas can lead to explosions and forest fires.Corrosion processes hiding under the coating due to poor adhesion and due to non-fulfillment of their functions by the coating lead to increased peeling of insulation and the formation of new corrosion foci, including stress-corrosion processes. Consequently, imperfect insulation coating and insufficient adhesion to metal are one of the main causes of accidents on main pipelines.The purpose of this work was to study and prove the chemical interaction of the functional groups of asmol insulation compositions with the metal surface. In the course of work, the following tasks were solved:- assessment of the ratio of initial adhesion parameters obtained in laboratory and route conditions and their values after 1.5 and 6 years of operation;- study of the IR spectrum in order to prove the presence of functional groups in the asmol material;- study of the protective capacity of the asmol coating structure in an aggressive corrosive environment at different temperatures.Methods were used to measure the quantitative adhesion of the anti-corrosion coating and the peel area during cathode polarization, in accordance with State Standard R 51164-98. The composition of the asmol material was studied by IR spectroscopy.It has been shown that functional groups, the presence of which has been confirmed by spectral analysis, of asmol material in the insulation coating make it possible to chemically adhere to steel. Indirect proof of this is the stability of the adhesion strength over time, the cohesive separation of the asmol coating in determining adhesion indicators under trace conditions and the relatively small area of coating detachment during cathode polarization.

Russian diplomacy and western gas wars against Russia

The article is devoted to the study the use by Western countries, primarily the United States and the EU, of the gas factor for political and economic pressure on Russia in order to squeeze it out of world gas markets, primarily European, and reduce the fl ow of funds from Russian gas exports to the state budget. The article analyzes how, in order to achieve their goals, the United States and a number of members of the European Union manipulate the actions of Qatar, Turkey and the Balkan countries to disrupt the implementation of large gas projects to deliver gas from Russia to Europe through main gas pipelines along the bottom of the Baltic and Black Seas, bypassing Ukrainian transit. Special attention how the West has used and is using Ukraine to displace Russian pipeline gas from European markets. The article also considers how the West has used and is using Ukraine to displace Russian pipeline gas from European markets. Special attention is paid to the role of liquefi ed natural gas (LNG)to increase the supply of Russian gas to the world market, which makes it possible to reduce Russia's dependence on gas exports through pipelines. The issue of prospects for the reorientation of gas exports from the West to the East, primarily to China, is also being considered.

FEATURES OF CALCULATING LONGITUDINAL DISPLACEMENTS OF PIPELINES LAID IN HETEROGENEOUS SOILS

Achieving and maintaining the required reliability of the linear part of the main gas pipelines is of particular importance. Emergency destruction usually leads to large gas leaks into the atmosphere and undersupply to consumers, significant costs for the restoration of main gas pipelines. The difficulty and cost of carrying out repairs of main gas pipelines directly depends on the difficult conditions of the route and special technical solutions are needed to achieve the stability and reliability of pipelines on low-bearing soils. Thus, on existing gas pipelines, their longitudinal movements occur under the action of longitudinal forces, which leads to an increase in the stress state of gas pipelines and even the destruction of pipes. The significant time duration of the increase in gas pipeline movements indicates that these movements occur due to the rheological properties of soils. An analysis of the stress state of such sections of gas pipelines is necessary to assess their reliability, timing and methods of repair.

Experimental Study of Avalanche Damage Protection Methods for Main Steel Gas Pipelines.

This paper conducted an experimental study of reduced models of a main gas pipeline for avalanche damage considering operational conditions. Two options were considered as a method of avalanche damage prevention: single steel rings at the crack edges and steel winding with a winding pitch of 0.25 m. For the tension force, 5% of the steel wire breaking force was taken, which was equal to 1 mm. The ambient environment was simulated by a climatic chamber, where two options of temperature loads were considered: +20 °C and -10 °C. It was found that reinforcement with single rings of pipeline models under conditions of positive (+20 °C) and negative (-10 °C) temperatures showed that the crack opening width in the ring direction decreased 1.63 times and 1.9 times, accordingly. The crack length (longitudinal direction) decreased 2.18 times and 2.45 times, accordingly. The reinforcement of the pipeline models with prestressed wire winding on the crack propagation under conditions of positive (+20 °C) and negative (-10 °C) temperatures showed that the width of the crack opening in the ring direction decreased 1.5 times and 1.46 times, accordingly. The crack length (longitudinal direction) decreased 1.4 times and 1.44 times accordingly, which is a positive moment in addressing the issue of the localisation and stoppage of a crack fracture in main gas pipelines. Simultaneously, the analysis of the prestressed pipelines model test results on crack fracture propagation showed that single rings are more effective, which decreased the crack opening width by 1.1 times and the crack length up to 1.5. Therefore, the experimental results obtained positively complement the available methods of crack localisation in main gas pipelines, which can be used by engineers and research communities when designing or reinforcing existing operating main steel gas pipelines.

THE INFLUENCE OF SURFACE EDDY CURRENT PROBE SIGNAL SMOOTHING ON ASSESSING STRESS-CORROSION CRACKS DEPTH IN MAIN GAS PIPELINE

The paper presents the results on the influence of signals smoothing of absolute and differential surface eddy current probes (ECP) above an individual crack and a group of stress-corrosion cracks on the accuracy of estimating the depths of stress-corrosion cracks during eddy current flaw detection of a main gas pipeline (MGP). Mathematical models demonstrate that the degree of signal smoothing of the surface ECP over an individual crack is higher than the degree of smoothing of the ECP signal over a group of stress-corrosion cracks in the MGP. Smoothing results in a decreased resolution of the surface ECP signal. The differential surface ECP is characterized by a higher resolution than the similar absolute surface ECP. The study demonstrates the reduction in amplitude difference between the actual signals of the absolute surface ECP over an individual crack and a group of stress-corrosion cracks, compared to the smoothed signal of the surface ECP. In the estimates of depths in the group of stress-corrosion cracks in MGP, obtained from the amplitude of the actual signal of the absolute surface ECP, where smoothing of the ECP signal is excluded, a significant reduction in the relative error is observed.

Diagnostyka stanu technologicznego gazociągów na podstawie składu transportowanych mieszanin gazowych

The efficiency of natural gas transportation hinges largely on the quality of technological processes involved. Imperfect separation process can lead to the liquid particles remaining in the gas and entering the transport systems, causing various technological issues with gas pipelines (clogging, hydrate formation, corrosion wear, etc.). The presence of mechanical particles in gas mixtures accelerates the degradation of metallic components of the transport system due to erosion. Additionally, the multiphase nature of gases contributes to complications during transportation, altering the quality indicators when different gas qualities are mixed. Consequently, the composition of gas mixtures, their mechanical particles, moisture, and other indicators, deviate non-linearly from their initial values. The technological condition of the main gas pipelines significantly impacts their discharge capacity and hydraulic characteristics. Failure to clean natural gas to current standards and requirements at production stations can result in condensation of water and hydrocarbon vapours in pipelines, leading to the accumulation of the liquid phase in the cavities of the pipeline and the formation of blockages due to hydrate compounds formation, the reduction of the cross-section of the gas pipeline or its complete blockage. Sediment accumulation on the inner surfaces of gas pipelines installed in complex geographical conditions adversely affects transportation system, increasing maintenance, energy, and transportation costs. Utilizing gas composition as an auxiliary tool (indicator) for diagnosing various technological processes and predicting transport parameters has been investigated in numerous research works in the oil and gas production industry.

FORMALIZATION OF THE PRINCIPLE, METHOD AND METHOD OF DEVELOPING A DIGITAL IMAGE OF THE LINEAR PART OF THE MAIN GAS PIPELINE

Uninterrupted gas supply to consumers and ensuring the design volume of pumping provides for the absence of accidents and incidents. Accidents during the operation of main gas pipelines lead to significant social, environmental and material losses. Due to the long-term operation and expiration of the resource of sections of gas pipelines operated on the territory of the Russian Federation, an urgent task is to increase their reliability and reduce accidents. At the same time, one of the prevailing conditions is the reliability of the linear part, which is formed at the design stage, provided and maintained during operation. To ensure reliable and trouble-free operation of the main gas pipeline, many different measures are carried out, as well as the systems necessary to assess and maintain the specified technical condition parameters are used. In order to reduce the industrial operation of main gas pipelines by reliably assessing the technical condition of the linear part and identifying potentially dangerous sections, a digital model is being developed that allows to accurately assess the technical condition of the pipeline section under examination.

Numerical analysis of the regularities of the infuence of pipe steel degradation on the reliability of corroded main gas pipelines used for transportation of gas-hydrogen mixtures

Numerical analysis of the regularities of the infuence of pipe steel degradation on the reliability of corroded main gas pipelines used for transportation of gas-hydrogen mixtures

ШВИДКІСТЬ КОРОЗІЇ НИЗЬКОВУГЛЕЦЕВИХ ТРУБНИХСТАЛЕЙ У РІЗНИХ АГРЕСИВНИХ СЕРЕДОВИЩАХ

Low-carbon steels are the main material for the production of main oil and gas pipelines. Currently, new generation steels of the X70, X80 type are used in global practice, however long-term pipelines are made of 17Г1C steels (X50, X52). Corrosion of the inner and outer parts of pipes is the main factor in the failure of pipelines. The study examines the influence of aggressive environments on the corrosion rate of low-carbon steels of different generations. It was found that for a more aggressive environment the difference in corrosion rate for different steels becomes more significant, and X80 steel showed the best indicators of corrosion resistance in various aggressive environments.

Finite-Element Modeling of the Temperature Effect on Extended Avalanche Damage of Gas Main Pipelines.

The dynamic stress-strain state and fracture of a steel main gas pipe section between supports with a straight-through crack was analyzed with consideration of the temperature effect on changes in the mechanical properties of the pipe material. The numerical solution of the problem was implemented in the ANSYS-19.2/Explicit Dynamics software package. The process of fracture in a section of the gas pipeline "Beineu-Bozoy-Shymkent" with a linear crack in the temperature range of -40 °C to +50 °C at the operating pressure of 7.5 MPa and critical pressure equal to 9.8 MPa was considered. As a result, it was found that at the initial growth of the internal pressure from working pressure to critical pressure, the length of the crack doubled. At the same time, the process had a local characteristic. Further development of the crack had the nature of avalanche fracture and depended on the temperature of the steel pipeline. With increasing temperature, there was also an increase in the length of the crack at the avalanche fracture. Thus, at a temperature of 40 °C, the crack lengthened 67.75-fold; at a temperature of -10 °C, the crack lengthened 68-fold; at a temperature of +20 °C, the crack lengthened 68.25-fold; and at a temperature of +50 °C, the crack lengthened 68.5-fold. In this work, this difference was 75% of the initial crack length. This fact will be used for further development of the technique of strengthening damaged pipe sections using bandages.

Numerical model of interaction of a mobile lift chain with a main gas pipeline pipe in the process of repair work

The paper proposes an original design of a mobile lifting device for diagnosing and repairing support nodes of above-ground segments of gas pipelines without stopping gas transportation. When using such a device, the rollers of the lifting chain interact with the surface of the pipe, which can possibly cause additional stresses in the gas pipeline. At the first stage of studying this problem, a model of a typical gas pipeline overhead crossing for the Carpathian region was built and the maximum operating force that should be developed by the mobile lift during repair operations was determined. At the second stage, a finite-element model of the interaction of the mobile lift chain with the main gas pipeline pipe was built. The additional equivalent stresses arising from the contact of the rollers of the lifting chain with the pipe surface were estimated. Recommendations are given to ensure the safe operation of the gas pipeline when using a mobile lift for local lifting of the pipe above the support of above-ground segments of gas pipelines.

The throughput capacity of the main gas pipeline when transporting gas-hydrogen mixtures

To determine the effect of hydrogen concentration in the gas-hydrogen mixture on the throughput capacity of the main gas pipeline and the volume of energy transported by it. The range of molar concentrations of hydrogen in the gas-hydrogen mixture up to and including 20%, which does not require significant technical modernisation of the system, was investigated.Performing theoretical studies and applying mathematical modelling methods to establish the regularities of thermo hydrodynamic processes in a gas pipeline, gas turbine and centrifugal blowers while transporting gas-hydrogen mixtures.In the example of a gas turbine unit widely used in the gas transmission system of Ukraine, it was found out that the molar content of hydrogen, if it does not exceed 20%, has a negligible effect on its rated power and other energy parameters. Adding hydrogen to natural gas with the above molar content will lead to a slight decrease in the pipeline system's capacity (up to 5%) and a significant reduction in the volume of energy transportation (up to 18%).The next stage of the study is to determine the impact of gas-hydrogen mixture properties on the pipeline capacity, taking into account changes in seasonal factors and the degree of system load.A method and software have been developed to predict the pipeline capacity and energy transfer volume for the transportation of gas-hydrogen mixtures, taking into account the influence of seasonal factors, gas-dynamic characteristics of blowers, and combinations of gas-pumping units at compressor stations.Modern international standards are used to calculate gas-hydrogen mixtures' physicochemical and thermodynamic properties under standard and operating conditions. The originality of the approach lies in the fact that the compressor station and the linear section of the gas pipeline are considered as a SLE gas-dynamic system.

PROSPECTS FOR THE DEVELOPMENT OF PIPELINE GAS TRANSPORT

In connection with the global trends in the development of green energy, as well as with the development of gas production in the territory of the Republic of Kazakhstan, the issues of gasification of the country, gas transportation to the consumer are becoming particularly relevant. The article provides a historical overview of gas transport, a comparative analysis of various types of gas transport, the advantages of pipeline gas transport, as well as an overview of the development of the gas industry in general and in particular, issues of gasification, gas transport on the example of the National operator of main gas pipelines JSC “Intergas Central Asia”. The issues of gasification of the country, in particular, the northern regions and Astana, were considered. The analysis and prospects for the development of the gas industry and gas companies in Kazakhstan were also carried out. According to the Roadmap for the country’s gasification, special attention is paid to the gasification of the northern and central regions of the country, where the provision of gas to settlements along the Saryarka gas pipeline route is being considered in stages. The statistics of the branches of JSC “Intergas Central Asia”, the sites that each branch serves, are given. In conclusion, recommendations are given on the effective use of the country’s gas resources and a gradual transition to “clean” energy.

Patterns of magnetic stray field distribution along the surface of an underground main gas pipeline and an elastically bent pipe

Patterns of magnetic stray field distribution along the surface of an underground main gas pipeline and an elastically bent pipe