scholarly journals Regularities of safe control of piston compressor units of mobile compressor stations

2021 ◽  
pp. 76-81
Author(s):  
Z.N Matsuk ◽  
T.V Bunko ◽  
A.S Belikov ◽  
V.A Shalomov
Keyword(s):  
Natural Gas ◽  
Gas Pressure ◽  
Gas Pipeline ◽  
Relative Mass ◽  
Time Interval ◽  
Relative Pressure ◽  
Gas Pipelines ◽  
Mobile Compressor ◽  
Gas Pumping ◽  
Main Gas Pipeline

Purpose. Ensuring the optimal mode of gas transportation from local sections of the main gas trunkline (GT), subject to repair (maintenance) and/or shutdown, to existing main gas trunkline based on the calculation, determination, and establishment of rational values of the operating modes of mobile compressor stations during the entire time of gas pumping. Methodology. The studies are based on existing physical principles and laws that describe the effect of the properties of natural gas and the geometric parameters of pipelines through which gas is pumped on the dynamics of changes in the mass and pressure of the transported gas. The calculation of the change in the mass and pressure of the gas in the gas pipeline from which the gas is pumped is based on a number of existing theoretical and empirical dependencies included in the generally accepted methods for their calculation. Known physical relationships and mathematical models are used to carry out the calculations. Findings. The mass approach to the issue of calculating the gas transportation time is more mathematically accurate than the volumetric one. The ratio of the relative mass to the relative gas pressure in a localized section of the main gas pipeline, during the entire pumping time, is a constant value. The use of the values of the quantities obtained at the point of intersection of the graphs of changes in the relative mass and relative pressure of the gas, in the preliminary calculation of the time for pumping gas, or pressure, or mass, or the volume of gas in each time interval, makes it possible to select the optimal rate of building up/reducing gas pressure by compressor units and optimal modes of gas transportation by operating gas pipelines during the operation of mobile compressor stations. Originality. The proposed approach to calculating and determining the time of gas pumping by mobile compressor stations from local sections of the main gas pipelines subject to repair (maintenance) and/or shutdown to sections of existing main gas pipelines proves that it is advisable to establish stable patterns in the transportation of natural gas using reciprocating compressor units only after modeling in time the change in the mass and pressure of gas in the local section of the main gas pipeline from which the gas is pumped. Practical value. The proposed approach to optimizing the time of gas pumping by mobile compressor stations makes it possible to increase the level of energy and resource efficiency of gas transmission enterprises, as well as to improve the technical and economic indicators of technologies for repairing the main gas pipelines, compressor stations of main gas pipelines associated with the need to bleed gas from sections of the main (technological) pipelines subject to repair (maintenance) and/or shutdown. Optimization of gas pumping time significantly reduces the time spent by employees of gas transmission enterprises under the influence of hazardous and harmful production factors, thereby reducing the level of relevant risks. Gas emissions and associated risks are reduced by 90%.

scholarly journals REGULATORY PROVISION OF SAFETY OF GAS TRANSPORT. CONSTRUKTIONAL DESIGN OF MOBILE COMPRESSOR STATIONS

2021 ◽  
pp. 13-19
Author(s):  
V. BIELIKOV ◽  
Z. MATSUK
Keyword(s):  
Natural Gas ◽  
Gas Pressure ◽  
Gas Pipeline ◽  
Industrial Safety ◽  
Technical Requirements ◽  
The World ◽  
Transportation Process ◽  
Mobile Compressor ◽  
Main Gas Pipeline ◽  
Gas Supply

Problem statement. The basis for the safety and efficiency of the main gas transportation in the world is the tightness of the gas transportation system. A component of the level of industrial safety and efficiency of gas transmission enterprises is the emissions of natural gas into the working area, the environment and the associated costs. Numerous methods of repairing pipeline gas transportation facilities, such as enhancing the bearing capacity of pipelines, repairing defects under gas pressure without interrupting the transportation process, etc., are either not devoid of risks from the point of view of industrial safety, or are energy and resource inefficient. The main type of repair that restores the operable state of the gas transmission system is the replacement of defective equipment, but it is still associated with the release of large volumes of natural gas into the environment. In the second decade of the 2000s, thanks to the rapid development of compressor technology and the invention of a sufficient number of ways to connect compressor units (stations) to main gas pipelines, without stopping the gas transportation process, gas transmission enterprises of the world had a real opportunity to evacuate gas from pipeline sections subject to repair (maintenance ) or accumulate it (control gas pressure in local areas), but the analysis of world experience in the development of gas pressure control technology in localized sections of gas pipelines allows us to assert that there are certain disparities between them in terms of operational safety and the complete absence of regulatory support for the transportation process in Ukraine gas using mobile compressor stations. With this approach to the production process, it is difficult to improve the safety and efficiency of the gas transportation process. The potential for reducing natural gas emissions from the world's gas industry reaches billions of cubic meters of natural gas per year. Purpose of the article. Development of technical requirements for mobile compressor units (stations), which will make it possible to design domestic gas compressor units (stations) capable of safely performing work on pumping natural gas from a localized section of the main gas pipeline to an existing main gas pipeline, within no more than 96 hours, without restrictions on gas supply to consumers. Conclusion. The technical requirements developed by us for mobile compressor units (stations) allow us to design domestic compressor units (stations) capable of safely performing work on pumping natural gas from a localized section of the main gas pipeline to the existing main gas pipeline, within no more than 96 hours, without restrictions on gas supply to consumers.

scholarly journals JUSTIFICATION OF THE USE OF THE ELECTRIC DRIVE AT THE COMPRESSOR STATIONS OF THE MAIN GAS PIPELINE

2021 ◽  
Vol 1 (1) ◽  
pp. 231-232
Author(s):  
Dmitriy Kononov
Keyword(s):  
Electric Drive ◽  
Gas Pipeline ◽  
Gas Pipelines ◽  
Gas Pumping ◽  
Main Gas Pipeline

The situation with the drive of compressor stations of main gas pipelines is analyzed. Based on the calculations carried out, a conclusion is made about the efficiency of using electricity for gas pumping

scholarly journals Modeling of the modes of natural gas transportation by main gas pipelines in the conditions of underloading

2019 ◽  
pp. 35-42
Author(s):  
О. B. Vasyliv ◽  
О. S. Titlov ◽  
Т. А. Sagala
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
Gas Pipeline ◽  
Total Power ◽  
Load Factor ◽  
Gas Pipelines ◽  
Efficient Operation ◽  
Gas Pumping ◽  
Pumping Units ◽  
Matlab Programming

The current state of transit of natural gas through the Ukrainian gas transmission system (GTS) is estimated in the paper. The prerequisites for further reduction of the GTS load in the coming years are considered, in particular in the direction of Europe through the gas measuring station "Orlivka" (south direction), taking into account the construction of alternative bypass gas pipelines. On the basis of the review of literature sources on the problem of efficient operation of gas pipelines under conditions of underloading, a method for determining the capacity and energy consumption of the gas pipeline for a given combination of working gas pumping units (GPU) was developed. The Ananyev-Tiraspol-Izmail gas pipeline at Tarutino-Orlivka section was selected as the object of research. The methodology includes the calculation of the physical properties of gas by its composition, the calculation of gas compression, the calculation of the linear part, the gas flow to the compressor station's own needs, and the calculation of the total power of the gas-pumping units under the specified technological limitations. With the help of the original software developed in the MATLAB programming language, cyclical multivariate calculations of the capacity and energy consumption of the gas pipeline were carried out and the operating modes of the compressor shop were optimized in the load range from 23 ... 60 million m3/day. Optimization criterion is the minimum total capacity of the GPU. Variable parameters at the same time are the speeds of the superchargers, different combination of working GPU, load factor. According to the results of the optimization graphical dependences were constructed: the optimum frequency of the rotor of the supercharger on the performance of the pipeline; changes in power and pressure depending on the performance of the pipeline when operating a different combination of superchargers. Recommendations have been developed to minimize fuel gas costs at the compressor station.

Comparison of PIR to PIPESAFE-Based 1% Lethality Zones for Natural Gas Pipelines

2014 ◽  
Author(s):  
Aleksandar Tomic ◽  
Shahani Kariyawasam
Keyword(s):  
Natural Gas ◽  
Small Diameter ◽  
Gas Pipeline ◽  
Accurate Estimation ◽  
Simple Relationship ◽  
Gas Pipelines ◽  
Friction Forces ◽  
Natural Gas Pipelines ◽  
Decay Factor ◽  
Outflow Rate

A lethality zone due to an ignited natural gas release is often used to characterize the consequences of a pipeline rupture. A 1% lethality zone defines a zone where the lethality to a human is greater than or equal to 1%. The boundary of the zone is defined by the distance (from the point of rupture) at which the probability of lethality is 1%. Currently in the gas pipeline industry, the most detailed and validated method for calculating this zone is embodied in the PIPESAFE software. PIPESAFE is a software tool developed by a joint industry group for undertaking quantitative risk assessments of natural gas pipelines. PIPESAFE consequence models have been verified in laboratory experiments, full scale tests, and actual failures, and have been extensively used over the past 10–15 years for quantitative risk calculations. The primary advantage of using PIPESAFE is it allows for accurate estimation of the likelihood of lethality inside the impacted zone (i.e. receptors such as structures closer to the failure are subject to appropriately higher lethality percentages). Potential Impact Radius (PIR) is defined as the zone in which the extent of property damage and serious or fatal injury would be expected to be significant. It corresponds to the 1% lethality zone for a natural gas pipeline of a certain diameter and pressure when thermal radiation and exposure are taken into account. PIR is one of the two methods used to identify HCAs in US (49 CFR 192.903). Since PIR is a widely used parameter and given that it can be interpreted to delineate a 1% lethality zone, it is important to understand how PIR compares to the more accurate estimation of the lethality zones for different diameters and operating pressures. In previous internal studies, it was found that PIR, when compared to the more detailed measures of the 1% lethality zone, could be highly conservative. This conservatism could be beneficial from a safety perspective, however it is adding additional costs and reducing the efficiency of the integrity management process. Therefore, the goal of this study is to determine when PIR is overly conservative and to determine a way to address this conservatism. In order to assess its accuracy, PIR was compared to a more accurate measure of the 1% lethality zone, calculated by PIPESAFE, for a range of different operating pressures and line diameters. Upon comparison of the distances calculated through the application of PIR and PIPESAFE, it was observed that for large diameters pipelines the distances calculated by PIR are slightly conservative, and that this conservativeness increases exponentially for smaller diameter lines. The explanation for the conservatism of the PIR for small diameter pipelines is the higher wall friction forces per volume transported in smaller diameter lines. When these higher friction forces are not accounted for it leads to overestimation of the effective outflow rate (a product of the initial flow rate and the decay factor) which subsequently leads to the overestimation of the impact radius. Since the effective outflow rate is a function of both line pressure and diameter, a simple relationship is proposed to make the decay factor a function of these two variables to correct the excess conservatism for small diameter pipelines.

scholarly journals MODELING COMPUTATIONAL FLUID DYNAMICS OF MULTIPHASE FLOWS IN ELBOW AND T-JUNCTION OF THE MAIN GAS PIPELINE

Transport ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Yaroslav Doroshenko ◽  
Julia Doroshenko ◽  
Vasyl Zapukhliak ◽  
Lyubomyr Poberezhny ◽  
Pavlo Maruschak
Keyword(s):  
Natural Gas ◽  
Multiphase Flows ◽  
Linear Part ◽  
Erosive Wear ◽  
Gas Pipeline ◽  
Solid Particles ◽  
Ansys Fluent ◽  
Gas Main ◽  
Discrete Phase ◽  
Main Gas Pipeline

The research was performed in order to obtain the physical picture of the movement of condensed droplets and solid particles in the flow of natural gas in elbows and T-junctions of the linear part of the main gas pipeline. 3D modeling of the elbow and T-junction was performed in the linear part of the gas main, in particular, in places where a complex movement of multiphase flows occurs and changes its direction. In these places also occur swirls, collisions of discrete phases in the pipeline wall, and erosive wear of the pipe wall. Based on Lagrangian approach (Discrete Phase Model – DPM), methods of computer modeling were developed to simulate multiphase flow movement in the elbow and T-junction of the linear part of the gas main using software package ANSYS Fluent R17.0 Academic. The mathematical model is based on solving the Navier–Stokes equations, and the equations of continuity and discrete phase movement closed with Launder–Sharma (k–e) two-parameter turbulence model with appropriate initial and boundary conditions. In T-junction, we simulated gas movement in the run-pipe, and the passage of the part of flow into the branch. The simulation results were visualized in postprocessor ANSYS Fluent R17.0 Academic and ANSYS CFD-Post R17.0 Academic by building trajectories of the motion of condensed droplets and solid particles in the elbow and T-junction of the linear part of the gas main in the flow of natural gas. The trajectories were painted in colors that match the velocity and diameter of droplets and particles according to the scale of values. After studying the trajectories of discrete phases, the locations of their heavy collision with the pipeline walls were found, as well as the places of turbulence of condensed droplets and solid particles. The velocity of liquid and solid particles was determined, and the impact angles, diameters of condensed droplets and solid particles in the place of collision were found. Such results provide possibilities for a full and comprehensive investigation of erosive wear of the elbow and T-junction of the linear part of the gas main and adjacent sections of the pipeline, and for the assessment of their strength and residual life.

scholarly journals Improving the efficiency of gas pipeline cleaning by controlling the speed of the gas cleaning

2020 ◽  
pp. 29-35
Author(s):  
V. Ya Grudz ◽  
N. B. Slobodian
Keyword(s):  
High Speed ◽  
Moving Boundary ◽  
Linear Part ◽  
Initial Pressure ◽  
Gas Pipeline ◽  
Technological Scheme ◽  
Gas Pipelines ◽  
Technological Parameters ◽  
Degree Of Reduction ◽  
Main Gas Pipeline

An important aspect of improving the hydraulic efficiency of pipeline transport is its periodic cleaning with mechanical cleaning devices. Cleaning gas pipelines with cleaning pistons is a technologically complex process. It is advisable to adjust the speed of the piston to increase the efficiency of cleaning the pipeline with the crossed track profile. On the ascending and plain sections of the route, maintain a high speed of movement of the device, and on the descending it to reduce. To slow down the movement of the piston in the downstream sections of the main gas pipelines, it is proposed to change the technological scheme of the linear part. It is suggested to use a looping connection to change the flow chart. The change of the speed of movement of the treatment device when changing the technological scheme of the main gas pipeline was evaluated. The influence on the dynamics of the movement of the cleaning piston of the main parameters of the pipeline and looping, as well as the parameters of the movement of the piston itself, are investigated. A mathematical model of the process is built, on the basis of the implementation of which the regularities of the treatment device movement when changing the technological scheme of the gas pipeline are established. An equation was obtained to find the ratio of the mass flow rates of gas in the main gas pipeline before and after connecting the loop, which can be solved by the iteration method. The algorithm is developed and the program of calculation of the degree of reduction of the speed of movement of the piston is developed, depending on the kind of technological parameters and technical characteristics of the treatment device and the pipeline. Based on the calculations, the graphical dependences of the relative speed of the piston on the technological parameters and technical characteristics of the main pipeline were constructed. The authors found that the greatest effect on the degree of reduction of the speed of the piston has the length of the loop. It has been investigated that a decrease in the initial pressure and an increase in the final pressure, as well as an increase in the pressure drop at the moving boundary, lead to an improvement in the braking conditions

High Energy Natural Gas Internal Corrosion Susceptibility Analysis

2014 ◽  
Author(s):  
David Owen ◽  
Simon Schapira
Keyword(s):  
Carbon Dioxide ◽  
Natural Gas ◽  
Hydrogen Sulphide ◽  
Free Water ◽  
High Energy ◽  
Gas Pipeline ◽  
Gas Pipelines ◽  
Internal Corrosion ◽  
Natural Gas Pipelines ◽  
Corrosion Susceptibility

Alliance Pipeline operates an integrated Canadian and U.S. high-pressure, rich natural gas transmission pipeline system. Rich natural gas pipelines are unique in that the product transported in these pipelines contains greater amounts of higher molecular weight hydrocarbons than would be transported in a dry natural gas pipeline. The specifications for gas quality however are very similar and require the product to contain less than sixty five mg/m3 water, no free liquids and/or objectionable materials such as bacteria, ashphaltene, gum, etc. The acid gases, carbon dioxide and hydrogen sulphide, are also required to be below certain values (see Table 1). Corrosion is not expected to occur under these conditions due to the lack of free water available for the development of an electrochemical corrosion cell. However, there are instances where the gas quality may vary and this gas enters facility piping for short periods of time. A method has been developed by Pipeline Research Council International (PRCI) to determine the internal corrosion susceptibility for dry gas natural gas pipelines but there are currently no industry accepted models which determine the internal corrosion susceptibility for high energy natural gas (HENG) pipeline systems. Accordingly, it is important for operators of pipelines with high energy natural gas (HENG) to collect and analyze these off specification events and develop a method to determine the relative impact on internal corrosion susceptibility. It is perhaps more important for operators to use this method to develop a strategy to prioritize facility piping for inspection and confirm the absence of internal corrosion. An Internal Corrosion Susceptibility Assessment (ICSA) method has been developed for HENG which considers off specification water, carbon dioxide, and hydrogen sulphide contents in the HENG. The analysis has been enhanced to also consider low temperature operation and hydrocarbon dew-point variations. The model has been effectively trialed over the last number of years to prioritize inspections and has been further tested against PRCI research and models developed for dry gas internal corrosion susceptibility. All internal corrosion models need to identify free water as prime contributor to susceptibility, thus the subject model is considered adaptable to other gas pipeline systems. This paper discusses the methods used to develop the model, the challenges encountered and results of the field inspections conducted.

scholarly journals An Investigation into the Volumetric Flow Rate Requirement of Hydrogen Transportation in Existing Natural Gas Pipelines and Its Safety Implications

Gases ◽  
2021 ◽  
Vol 1 (4) ◽  
pp. 156-179
Author(s):  
Abubakar Jibrin Abbas ◽  
Hossein Hassani ◽  
Martin Burby ◽  
Idoko Job John
Keyword(s):  
Natural Gas ◽  
Flow Rate ◽  
Compressibility Factor ◽  
Volumetric Flow Rate ◽  
Gas Pipeline ◽  
Internal Erosion ◽  
Gas Pipelines ◽  
Natural Gas Pipelines ◽  
Natural Gas Pipeline ◽  
Wide Range

As an alternative to the construction of new infrastructure, repurposing existing natural gas pipelines for hydrogen transportation has been identified as a low-cost strategy for substituting natural gas with hydrogen in the wake of the energy transition. In line with that, a 342 km, 36″ natural gas pipeline was used in this study to simulate some technical implications of delivering the same amount of energy with different blends of natural gas and hydrogen, and with 100% hydrogen. Preliminary findings from the study confirmed that a three-fold increase in volumetric flow rate would be required of hydrogen to deliver an equivalent amount of energy as natural gas. The effects of flowing hydrogen at this rate in an existing natural gas pipeline on two flow parameters (the compressibility factor and the velocity gradient) which are crucial to the safety of the pipeline were investigated. The compressibility factor behaviour revealed the presence of a wide range of values as the proportions of hydrogen and natural gas in the blends changed, signifying disparate flow behaviours and consequent varying flow challenges. The velocity profiles showed that hydrogen can be transported in natural gas pipelines via blending with natural gas by up to 40% of hydrogen in the blend without exceeding the erosional velocity limits of the pipeline. However, when the proportion of hydrogen reached 60%, the erosional velocity limit was reached at 290 km, so that beyond this distance, the pipeline would be subject to internal erosion. The use of compressor stations was shown to be effective in remedying this challenge. This study provides more insights into the volumetric and safety considerations of adopting existing natural gas pipelines for the transportation of hydrogen and blends of hydrogen and natural gas.

scholarly journals Diagnosing of the presence of liquid inclusions in the gas pipelines

2021 ◽  
pp. 156-161
Author(s):  
G. G. Ismayilov ◽  
◽  
R. A. Ismailov ◽  
F. N. Аhmadzada ◽  
◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Flow ◽  
Relaxation Times ◽  
Gas Pipeline ◽  
Calculation Error ◽  
Main Task ◽  
Gas Pipelines ◽  
Transport Stream ◽  
Transfer Mode ◽  
Use Of Services

Due to the insufficiently effective gas drying in preparing it for further transport on the main pipeline in the composition of the gas remains a sufficient amount of fluid. The presence of liquid inclusions in the transported streams causes a nonequilibrium behavior of such systems, which is not taken into account in traditional calculation methods and increases the calculation error. Therefore, to select an adequate transfer mode, it is necessary to diagnose the internal structure of natural gas systems, which is the main task of studying this article. In working on the basis of a generalized model of motion of the relaxation medium in the pipeline by the introduction of the equation of the state for nonequilibrium gases, the calculated ratios are obtained to estimate the hydraulic and nonequilibrium parameters of the gas flow. In order to numerically implement these relations, a computational algorithm was drawn up and on the basis of the operational data of the actual gas pipeline obtained appropriate estimates. The results of the calculations were shown that both the density and the pressure relaxation times are rather significant. This indicates the presence of liquid inclusions in the transport stream. Thus, the authors proposed a numerically implemented procedure for diagnosing the presence of liquid inclusions in natural gases, which can be recommended for the use of services engaged in the operation of main gas pipelines. Keywords: natural gas; gas pipeline; liquid inclusions; model; diagnostics.

scholarly journals IMPROVING THE EFFICIENCY OF FUNCTIONING OF REPAIR-OPERATING UNITS IN THE SYSTEM OF MAINTENANCE AND REPAIR OF MAGISTRALS

2019 ◽  
pp. 104-115
Author(s):  
V. Y. Grudz ◽  
V. V. Grudz ◽  
V. M. Bodnar ◽  
M. S. Chernetsky
Keyword(s):  
Linear Part ◽  
Gas Pipeline ◽  
Operating Conditions ◽  
Gas Pipelines ◽  
Maintenance And Repair ◽  
Technological Structure ◽  
Optimal Technology ◽  
Main Gas Pipeline ◽  
Operating Units

The classification of failures and damages of the linear part and its separate elements is carried out, variants of technology of carrying out of preventive and repair-restoration works and modular-technological structure of repair and maintenance units are formulated. Particular attention is paid to improving the efficiency of the operation of a separate repair and maintenance unit during maintenance and repair with a known layout scheme and a certain mode of control and restoration works by choosing the optimal technology of work and rational equipment of units and crews leaving for the route. On the basis of the analysis of the technology of work execution it is shown that only a small part of the repair and maintenance measures requires the use of powerful machinery and equipment, which include the first level of priority work on the replacement of gas pipeline sections, work, damage elimination, work on elimination of significant pipeline displacements, work for restoration of soil collapse of the main gas pipeline. In addition, each type of work on the objects of the linear part requires the use of the same vehicles. The type and number of vehicles depend on the particular operating conditions, as well as on the possibility and feasibility of purchasing and operating a particular type of equipment. The method of estimation of indexes of maintenance of linear part of main gas pipelines and efficiency of functioning of repair and maintenance units during maintenance and repair is developed.

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