Big encyclopedia of oil and gas. Gas distribution network

19.05.2019 Reviews

Gas supply- one of the forms of energy supply, which is an activity to provide consumers with gas, including the activity on the formation of a fund of explored gas fields, production, transportation, storage and supply of gas. one

Legislative and normative legal regulation of gas supply in the Russian Federation is based on:

The Constitution of the Russian Federation;

The Civil Code of the Russian Federation;

Federal Law "On Subsoil";

Federal Law "On Natural Monopolies";

Federal Law "On the Continental Shelf of the Russian Federation"

The Constitution of the Russian Federation is a fundamental document of Russian legislation; any legislative and by-laws are based on it and should not contradict it. According to the Constitution of the Russian Federation, land and other natural resources are used and protected in the Russian Federation as the basis of the life and activities of the peoples living in the corresponding territory. Land and other natural resources can be in private, state, municipal and other forms of ownership. According to the Constitution of the Russian Federation, the joint jurisdiction of the Russian Federation and the constituent entities of the Russian Federation includes, in particular, the issues of ownership, use and disposal of land, subsoil, water and other natural resources. 2

The RF Law "On Subsoil" contains the legal and economic foundations for the integrated rational use and protection of subsoil, protects the interests of the state and citizens of the Russian Federation, as well as the rights of subsoil users. In addition, it regulates relations arising in connection with the geological study, use and protection of the subsoil of the territory of the Russian Federation, its continental shelf, as well as in connection with the use of mining waste and associated processing industries, peat, sapropel and other specific mineral resources, including underground waters, brines and brine of salt lakes and sea bays.

The bowels are part of the earth's crust located below the soil layer, and in its absence - below the earth's surface and the bottom of reservoirs and watercourses, extending to depths available for geological study and development.

The Law of the Russian Federation "On Subsoil" defines that subsoil plots may be provided for the construction and operation of underground structures not related to the extraction of minerals, the construction and operation of underground facilities related to waste disposal, the construction and operation of oil and gas storage facilities, without any time limit. as well as for the formation of specially protected geological objects and other purposes.

The Federal Law "On Natural Monopolies" defines the legal foundations of federal policy in relation to natural monopolies in the Russian Federation and is aimed at achieving a balance of interests of consumers and subjects of natural monopolies, ensuring the availability of the goods they sell for consumers and the effective functioning of subjects of natural monopolies. This Federal Law applies to relations that arise in the commodity markets of the Russian Federation and in which subjects of natural monopolies, consumers, federal executive bodies, executive bodies of the constituent entities of the Russian Federation and local self-government bodies participate. The regulation of the activities of subjects of natural monopolies provided for by the said Federal Law cannot be applied in areas of activity that do not belong to natural monopolies, with the exception of cases established by federal laws.

The Federal Law "On Natural Monopolies" regulates the activities of subjects of natural monopolies, in particular, in the field of gas transportation through pipelines.

The Federal Law "On the Continental Shelf of the Russian Federation" defines the status of the continental shelf of the Russian Federation, the sovereign rights and jurisdiction of the Russian Federation on its continental shelf and their implementation in accordance with the Constitution of the Russian Federation, generally recognized principles and norms of international law and international treaties of the Russian Federation. Issues related to the continental shelf of the Russian Federation and activities on it, not provided for by this Federal Law, are regulated by other federal laws applicable to the continental shelf of the Russian Federation.

In order to ensure a unified approach to solving issues related to gas supply in the Russian Federation, on the part of the state authorities of the Russian Federation, state authorities of the constituent entities of the Russian Federation, local authorities, as well as organizations providing gas supply in the Russian Federation, the following principles of state policy are established in the specified area:

State support for the development of gas supply in order to improve the socio-economic living conditions of the population, ensure technical progress and create conditions for the development of the economy of the Russian Federation, taking into account industrial and environmental safety;

State regulation of the rational use of gas reserves, especially gas reserves of strategic importance;

Increasing the level of gasification of housing and communal services, industrial and other organizations located on the territories of the constituent entities of the Russian Federation, based on the formation and implementation of the corresponding federal, interregional and regional gasification programs;

Determination of the basics of gas pricing policy;

Creation of conditions for widespread use of gas as a motor fuel and raw material for the chemical industry of the Russian Federation;

Providing a reliable resource base for gas production;

Ensuring the energy security of the Russian Federation.

Federal gas supply system- a set of gas supply systems operating on the territory of the Russian Federation: the Unified Gas Supply System, regional gas supply systems, gas distribution systems and independent organizations. The federal gas supply system is one of the federal energy systems of the Russian Federation.

1.2 Security zones of the gas distribution network

Security zone of the gas distribution network- territory with special conditions of use, established along the routes of gas pipelines and around other objects of the gas distribution network in order to ensure normal conditions for its operation and to exclude the possibility of its damage.

Economic activity and the use of land plots, on the territory of which gas pipelines are located or near them, takes place under special conditions. This is due to the fact that, in accordance with the legislation of the Russian Federation, gas distribution networks are classified as hazardous production facilities. This is due to the explosive and fire hazardous properties of the gas transported through them. 3

Gas distribution network- the technological complex of the gas distribution system, consisting of external gas pipelines of settlements (urban, rural and other settlements), including inter-settlement ones, from the outlet disconnecting device of the gas distribution station (GDS), or another gas source, to the inlet gas pipeline to the gas consumption facility. The gas distribution network includes structures on gas pipelines, means of electrochemical protection, gas control points (hydraulic fracturing stations, gas distribution stations), cabinet control points (SHRP), an automated control system for the technological process of gas distribution (ACS TP RG).

Gas control station (GRP), installation (GRU)- technological device designed to reduce gas pressure and maintain it at specified levels in gas distribution networks.

Cabinet Gas Control Station (SHRP) - a cabinet-type technological device designed to reduce gas pressure and maintain it at specified levels in gas distribution networks. 4

The gas distribution networks include:

1) external, underground, aboveground and aboveground gas distribution pipelines, inter-settlement gas pipelines, gas pipelines-inlets with valves installed on them;

2) off-site gas pipelines of industrial enterprises;

3) crossings of gas pipelines through natural and artificial obstacles, including through rivers, railways and highways;

4) stand-alone gas control points located on the territory and outside the territory of settlements, industrial and other enterprises, as well as gas control points located in buildings, cabinets or blocks;

5) devices for electrochemical protection of steel gas pipelines from corrosion and means of telemechanization of gas distribution networks, objects of their electric drive and power supply. 5

The procedure for determining the boundaries of the security zones of gas distribution networks, the conditions for the use of land plots located within them, and restrictions on economic activities, the rights and obligations of operating organizations are set out in the Rules for the protection of gas distribution networks. These rules are valid throughout the territory of the Russian Federation. They are mandatory for legal entities and individuals who own land plots located within the security zones of the GDS, or design housing and civil and industrial facilities, engineering, transport and social infrastructure, or carry out any economic activity within the boundaries of such areas.

Any work in the security zones of gas distribution networks is carried out with strict compliance with the requirements for the safety of the opened networks and other utilities, as well as for the safe passage of special vehicles and pedestrian passage.

For GDS, security zones are established:

1) along the routes of external gas pipelines - in the form of an area bounded by conventional lines running at a distance of 2 meters on each side of the gas pipeline;

2) along the routes of underground gas pipelines made of polyethylene pipes when using a copper wire to designate the gas pipeline route - in the form of an area bounded by conventional lines passing at a distance of 3 meters from the gas pipeline from the side of the wire and 2 meters from the opposite side;

3) along the routes of external gas pipelines on permafrost soils, regardless of the pipe material - in the form of an area bounded by conventional lines running at a distance of 10 meters from each side of the gas pipeline;

4) around detached gas control points - in the form of a territory bounded by a closed line drawn at a distance of 10 meters from the boundaries of these objects. For gas control points attached to buildings, the security zone is not regulated;

5) along underwater crossings of gas pipelines through navigable and floating rivers, lakes, reservoirs, canals - in the form of a section of water space from the water surface to the bottom, enclosed between parallel planes spaced 100 m from each side of the gas pipeline;

6) along the routes of inter-settlement gas pipelines passing through forests and trees and shrubs - in the form of openings 6 meters wide, 3 meters on each side of the gas pipeline. For above-ground sections of gas pipelines, the distance from trees to the pipeline must be at least the height of the trees during the entire life of the gas pipeline.

Distances are counted when defining the protection zones of gas pipelines from the axis of the gas pipeline - for single-line gas pipelines and from the axes of the extreme lines of gas pipelines - for multi-line ones.

Standard distances are established both taking into account the importance of objects, the conditions for laying the gas pipeline, gas pressure, etc., and taking into account building codes and regulations approved by the authorized executive body in the field of urban planning and construction.

The establishment of protective zones of the gas pipeline and their application to regional land use maps is carried out in order to ensure the conditions for the safe operation of the gas pipeline by:

Exceptions for unauthorized construction and installation work, earthmoving, blasting and other types of work (with the exception of agricultural), which can in one way or another damage the technological equipment or gas pipeline communications;

Restrictions on other activities that may damage the gas pipeline (lighting an open fire, storing raw materials, products, bulk materials, installing any obstacles that worsen the access of the operating personnel to the gas pipeline facilities, etc.).

Protected zones are established around the gas pipeline facilities at the request of the operating organization by acts of executive authorities or local self-government and are applied to regional land use maps. 6 Compliance with restrictions on activities in protected zones is provided for by the Land Code and Federal Law 7.

The operating organization (the owner of the pipeline) is responsible for maintaining the protective zones of the gas pipeline in the proper fire-fighting condition.

The dimensions of the security zones of gas pipeline facilities are established in accordance with the rules. On the borders of land sections and crossings over navigable rivers, lakes, buffer zones are 100 m wide on each side of the gas pipeline. On the land side, the protection zones of the crossings are extended along the route to a distance of 50 m from the water's edge along the GWV 10% supply.

For multi-line gas pipelines in the sections of several gas pipeline lines in one corridor, it is allowed (in contrast to the existing standards) to establish both a single security zone covering all the corridor lines (25 m wide to the outside from the extreme lines), and a set of separate security zones for each of the corridor threads. The decision on this issue is taken by the operating organization based on the appropriateness in each specific case. This decision must be confirmed by acts of the executive authorities or local self-government.

On navigable rivers, work related to changing the channel within the boundaries of up to 1000 m from underwater crossings should be coordinated with the organization operating the gas pipeline.

The executive survey of gas distribution networks and the boundaries of their security zones is carried out in a single state or local coordinate system and is drawn up in accordance with the established procedure. Organizations - owners of gas distribution networks or operating organizations are obliged to include the materials of the executive survey in the composition of the materials for surveying the boundaries of the protected zones, which are transferred to the bodies that maintain the state land cadastre.

1.3 Protective zones of main pipelines

To exclude the possibility of damage to pipelines (for any type of their laying), security zones are established:

1. along the routes of pipelines transporting oil, natural gas, oil products, oil and artificial hydrocarbon gases - in the form of a plot of land bounded by conventional lines running 25 meters from the axis of the pipeline on each side;

2. along the routes of pipelines transporting liquefied hydrocarbon gases, unstable gasoline and condensate - in the form of a plot of land bounded by conventional lines running 100 meters from the axis of the pipeline on each side;

3. along the routes of multi-line pipelines - in the form of a plot of land bounded by conventional lines passing at the above distances from the axes of the extreme pipelines;

4. along underwater crossings - in the form of a section of water space from the water surface to the bottom, enclosed between parallel planes spaced from the axes of the extreme threads of the crossings by 100 meters on each side;

5. around tanks for storage and degassing of condensate, earthen barns for emergency release of products - in the form of a plot of land bounded by a closed line, 50 meters from the boundaries of the territories of these facilities in all directions;

6. around technological units for preparation of products for transport, head and intermediate pumping and loading pumping stations, tank farms, compressor and gas distribution stations, product measuring units, loading and unloading racks, underground gas storage stations, oil and oil products heating points - in the form of a section land bounded by a closed line spaced from the boundaries of the territories of the indicated objects by 100 meters in all directions.

Land plots included in the protected zones of pipelines are not withdrawn from land users and are used by them for agricultural and other work with mandatory compliance with the requirements.

In the protected zones of pipelines, it is prohibited to perform any kind of action that could disrupt the normal operation of pipelines or lead to damage, in particular:

1) move, fill up and break identification and signal signs, control and measuring points;

2) open hatches, wickets and doors of unattended amplifying points of cable communication, fences of linear fittings, cathodic and drainage protection stations, linear and inspection wells and other linear devices, open and close taps and valves, turn off or turn on communications, power supply and telemechanics pipelines;

3) arrange all kinds of landfills, pour out solutions of acids, salts and alkalis;

4) destroy bank protection structures, culverts, earth and other structures (devices) that protect pipelines from destruction, and the adjacent territory and the surrounding area from an accidental spill of transported products;

5) drop anchors, pass with anchors, chains, lots, drags and trawls released, carry out dredging and dredging operations;

6) light a fire and place any open or closed sources of fire.

In the protected zones of pipelines, without the written permission of pipeline transport enterprises, it is prohibited:

Erect any buildings and structures;

Plant trees and shrubs of all kinds, store feed, fertilizers, materials, hay and straw, arrange tethering posts, keep livestock, allocate fishing grounds, fish, as well as aquatic animals and plants, arrange watering places, cut and harvest ice;

Construct passages and crossings over pipeline routes, arrange parking lots for motor vehicles, tractors and machinery, arrange gardens and vegetable gardens;

To carry out reclamation earthworks, to construct irrigation and drainage systems;

To carry out all kinds of open and underground, mining, construction, assembly and blasting works, and ground leveling. Written permission to carry out blasting operations in the protected zones of pipelines is issued only after the enterprise performing these works submits the relevant materials provided for by the current Uniform Safety Rules for Blasting Operations;

To carry out geological survey, geological exploration, prospecting, geodetic and other prospecting work related to the construction of wells, pits and taking soil samples (except for soil samples).

Enterprises and organizations that have received written permission to carry out work in the protected zones of pipelines are obliged to perform them in compliance with the conditions ensuring the safety of pipelines and identification marks, and are responsible for damage to the latter.

Pipeline transport enterprises are allowed to:

Entrance to the pipeline and its facilities for maintenance and repair work in accordance with the driveway scheme agreed with the land user, road transport and other means.

In emergency situations, it is allowed to approach the pipeline and facilities on it along the route that ensures the delivery of equipment and materials to eliminate accidents with subsequent registration and payment of damages to landowners.

If the pipelines pass through the territory of restricted zones and special objects, then the relevant organizations must issue the workers servicing these pipelines with passes for inspection and repair work at any time of the day;

Arrangement within the security zone of pits for checking the quality of pipeline insulation and the state of their electrochemical protection against corrosion and carrying out other earthworks necessary to ensure the normal operation of pipelines, with a preliminary (at least 5 days before the start of work) notification of this to the land user;

Felling of trees in case of accidents on pipelines passing through forest lands, with the subsequent registration of felling tickets in the prescribed manner and with the cleaning of places from felling residues.

If necessary, pipeline transport enterprises can, in the course of the current maintenance of pipelines, cut wood in their protective zones with the issuance of felling tickets on a general basis. The wood obtained at the same time is used by the specified enterprises. eight

1.4 Restrictions imposed on land plots included in the security zones of the gas distribution network

To prevent damage or violation of the conditions of normal operation of the GDS, restrictions (encumbrances) are imposed on land plots included in the security zones of the networks.

In accordance with these encumbrances on the sites, it is prohibited:

1) build objects for housing and civil and industrial purposes;

2) demolish and reconstruct bridges, collectors, roads and railways with gas distribution networks located on them without preliminary removal of these gas pipelines in agreement with operating organizations;

3) destroy bank protection structures, culverts, earthworks and other structures that protect gas distribution networks from destruction;

4) move, damage, fill up and destroy identification marks, control and measuring points and other devices of gas distribution networks;

5) arrange landfills and warehouses, pour solutions of acids, salts, alkalis and other chemically active substances;

6) fence and partition off security zones, prevent personnel of operating organizations from accessing gas distribution networks, perform maintenance and repair damage to gas distribution networks;

7) light a fire and place sources of fire;

8) dig cellars, dig and cultivate the soil with agricultural and reclamation tools and mechanisms to a depth of more than 0.3 meters;

9) open wickets and doors of gas control points, cathodic and drainage protection stations, hatches of underground wells, turn on or off the power supply of communication facilities, lighting and telemechanics systems;

10) throw, attach and tie to supports and overground gas pipelines, fences and buildings of gas distribution networks, foreign objects, stairs, climb on them;

11) unauthorized connection to gas distribution networks.

Other types of work (forestry., Agricultural) that do not fall under the list of restrictions given above, and are not related to the violation of the land horizon and soil cultivation to a depth of more than 0.3 meters, are carried out by the owners, owners, users of land plots in the GDS protected zone only on condition written notification to the operating organization, the notification is submitted at least 3 working days before the start of work.

The procedure for approving GDS protected zones and imposing restrictions (encumbrances) on land plots within the protected zones.

The boundaries of the security zones of the GDS and the imposition of encumbrances (restrictions) on land plots included in the security zones is carried out on the basis of materials for surveying the boundaries of the security zone by the executive authorities in agreement with the owners, owners or users of land plots only with the designed (new) GDS.

The imposition of encumbrances (restrictions) on land plots included in the security zones is carried out on the basis of materials for surveying the boundaries of the security zone by the executive authorities without coordination with the owners, owners or users of land plots for existing GDSs.

The decision of the executive authority on the approval of the border of the security zone of the GDS and the imposition of encumbrances (restrictions) on the land plots included in it serves as the basis for cadastral work on the formation of parts of land plots included in the security zone, state cadastral registration with the assignment of cadastral numbers in the Unified State land register and state registration of encumbrances in the Unified State Register.

Cadastral works are carried out by the organization-owner of the GDS in accordance with the application and the decision of the executive authority on the establishment of security zones. Based on the results of cadastral work, the owner of the GDS or the operating organization is issued cadastral plans of land plots indicating the boundaries and registration cadastral numbers of parts of land plots included in the protected zone.

Losses caused to owners, owners or users of land plots as a result of the work are reimbursed in accordance with federal law.

The organizations in charge of the objects of the gas supply system located in the forests are obliged to:

Carry out the planned work, cut trees (shrubs) in the security zones of the gas supply system and outside such zones in the manner prescribed by the forest legislation of the Russian Federation.

In the event of an accident or catastrophe at the facility of the gas supply system, the organization - the owner of such a system or the operating organization authorized by it has the right to unimpeded delivery of the necessary forces and means to the place of the accident, catastrophe and is obliged to fully compensate the damage caused by it to the owner of the land plot on the territory of which the delivery was carried out the necessary forces and means.

On land plots classified as transport land, security zones are established with special conditions for the use of such land plots. The boundaries of the protected zones of the gas supply system objects are determined on the basis of building codes and regulations, rules for protecting main pipelines, and other regulatory documents approved in the prescribed manner. The owners of these land plots during their economic use cannot build any buildings, structures, structures within the established minimum distances to the objects of the gas supply system without the consent of the organization - the owner of the gas supply system or an organization authorized by it; such owners do not have the right to interfere with the organization of the owner of the gas supply system or an organization authorized by it in the performance of maintenance and repair of gas supply system facilities, liquidation of the consequences of accidents and disasters that have occurred on them.

The procedure for the use of land plots located in the security zone of the GDS.

Land plots located in the security zones of the GDS are not withdrawn from their owners, owners or users and can be used subject to the imposed restrictions (encumbrances).

The establishment of GDS protected zones does not entail a ban on transactions with land plots located in these protected zones.

The documents certifying the rights of owners, owners or users to land plots (certificates, cadastral passports) indicate the restrictions (encumbrances) of the rights of these owners, owners or users. 9

1.5 General requirements for gas distribution systems

The internal diameters of gas pipelines should be determined by calculation based on the condition of ensuring gas supply to all consumers during the hours of maximum gas consumption.

According to the working pressure of the transported gas, gas pipelines are divided into high pressure gas pipelines of I and II categories, medium pressure and low pressure in accordance with the table.

Table 1 - Classification of gas pipelines by pressure

Classification of gas pipelines by pressure	Type of transported gas	Working pressure in the gas pipeline, MPa
High	Natural	St. 0.6 to 1.2 inclusive
		St. 0.6 to 1.6 inclusive
	Natural and LPG	St. 0.3 to 0.6 inclusive
Middle		St. 0.005 to 0.3 inclusive
		Up to 0.005 inclusive

The gas pressure in internal gas pipelines and in front of gas-using installations must correspond to the pressure required for the stable operation of these installations, indicated in the technical data sheets of manufacturers, but should not exceed the values given in the table.

Table 2 - Gas pressure in internal gas pipelines and in front of gas-using installations.

Gas consumers		Gas pressure, MPa
	Industrial buildings in which the value of gas pressure is due to production requirements
	Other industrial buildings
	Household buildings of industrial enterprises, detached, attached to production buildings and built into these buildings
	Administrative buildings
	Boiler rooms:
	detached on the territory of industrial enterprises
	the same, on the territory of settlements
	attached, built-in and roofed industrial buildings
	attached, built-in and rooftop public, administrative and household buildings
	attached, built-in and roof residential buildings
	Public buildings (except for buildings in which the installation of gas equipment by the requirements of SNiP 2.08.02 is not allowed) and warehouse
	Residential buildings

The placement of external gas pipelines in relation to buildings, structures and parallel neighboring engineering networks should be carried out in accordance with the requirements of SNiP 2.07.01, and on the territory of industrial enterprises - SNiP II-89.

When laying underground gas pipelines with a pressure of up to 0.6 MPa in cramped conditions (when the distances regulated by regulatory documents cannot be fulfilled), in certain sections of the route, between buildings and under the arches of buildings, as well as gas pipelines with a pressure of over 0.6 MPa when approaching them with free-standing ancillary buildings (buildings without the constant presence of people) are allowed to be reduced to 50% of the distance specified in SNiP 2.07.01 and SNiP II-89. At the same time, in the areas of convergence and at a distance of at least 5 m in each direction from these areas, the following should be applied:

Seamless or electrically welded steel pipes, laid in a protective case, under 100% physical control of factory welded joints;

Polyethylene pipes laid in a protective case, without welded joints or connected by parts with embedded heaters (ZN), or butt-welded with 100% control of joints by physical methods.

When laying gas pipelines at distances corresponding to SNiP 2.07.01, but less than 50 m from public railways in the area of approach and 5 m in each direction, the depth of laying should be at least 2.0 m. Butt welded joints must pass 100% - control by physical methods.

In this case, the wall thickness of steel pipes should be 2-3 mm more than the calculated one, and polyethylene pipes should have a safety factor of at least 2.8.

Pipe connections should be made permanent. Connections of steel pipes with polyethylene pipes can be detachable and in places where fittings, equipment and instrumentation are installed. Detachable joints of polyethylene pipes with steel pipes in the ground can only be provided if a case with a control tube is installed.

Gas pipelines at the points of entry and exit from the ground, as well as gas pipelines inlets to buildings, should be enclosed in a case. The space between the wall and the case should be filled up to the full thickness of the structure to be crossed. The ends of the case should be sealed with elastic material.

Gas pipeline entries into buildings should be provided directly to the room where the gas-using equipment is installed, or to an adjacent room connected by an open opening.

Gas pipelines are not allowed to enter the premises of the basement and basement floors of buildings, except for natural gas pipelines in single-family and blocked houses.

Disconnecting devices on gas pipelines should include:

In front of detached or blocked buildings;

To disconnect risers of residential buildings above five floors;

In front of outdoor gas-using equipment;

In front of gas control points, except for hydraulic fracturing of enterprises, on the branch of the gas pipeline to which there is a disconnecting device at a distance of less than 100 m from the hydraulic fracturing;

At the exit from gas control points, looped through gas pipelines;

On branches from gas pipelines to settlements, individual microdistricts, quarters, groups of residential buildings, and with more than 400 apartments to a separate house, as well as on branches to production consumers and boiler houses;

When crossing water barriers with two or more lines, as well as one line with a water barrier width with a low water level of 75 m or more;

At the intersection of railways of the general network and highways of categories I-II, if the disconnecting device that ensures the interruption of the gas supply at the crossing section is located at a distance of more than 1000 m from the roads.

Disconnecting devices on overground gas pipelines laid along the walls of buildings and on supports should be placed at a distance (within a radius) from door and opening window openings at least:

For low pressure gas pipelines - 0.5 m;

For gas pipelines of medium pressure - 1 m;

For high-pressure gas pipelines of the II category - 3 m;

For high-pressure gas pipelines of category I - 5 m.

Underground gas pipelines:

Gas pipelines should be laid at a depth of at least 0.8 m to the top of the gas pipeline or case. In places where the movement of vehicles and agricultural machinery is not foreseen, the depth of laying steel gas pipelines can be at least 0.6 m.

The vertical distance (in the light) between the gas pipeline (case) and underground utilities and structures at their intersections should be taken taking into account the requirements of the relevant regulatory documents, but not less than 0.2 m.

At the intersection of gas pipelines with underground communication collectors and channels for various purposes, as well as in the places where gas pipelines pass through the walls of gas wells, the gas pipeline should be laid in a case.

The ends of the case should be brought out at a distance of at least 2 m in both directions from the outer walls of the structures and communications being crossed, when crossing the walls of gas wells - at a distance of at least 2 cm. The ends of the case should be sealed with waterproofing material.

At one end of the case, at the upper point of the slope (except for the intersection of the walls of the wells), a control tube should be provided that goes under the protective device.

In the annular space of the case and the gas pipeline, it is allowed to lay a service cable (communication, telemechanics and electrical protection) with a voltage of up to 60V, intended for servicing gas distribution systems.

Polyethylene pipes used for the construction of gas pipelines must have a safety factor of at least 2.5 in accordance with GOST R 50838.

Laying of gas pipelines from polyethylene pipes is not allowed:

On the territory of settlements at a pressure of over 0.3 MPa;

Outside the territory of settlements at a pressure of over 0.6 MPa;

For transportation of gases containing aromatic and chlorinated hydrocarbons, as well as the liquid phase of LPG;

At a gas pipeline wall temperature under operating conditions below minus 15 ° C.

When using pipes with a safety factor of at least 2.8, it is allowed to lay polyethylene gas pipelines with a pressure of more than 0.3 to 0.6 MPa in the territories of settlements with mainly one-two-story and cottage residential buildings. On the territory of small rural settlements, it is allowed to lay polyethylene gas pipelines with a pressure of up to 0.6 MPa with a safety factor of at least 2.5. In this case, the laying depth must be at least 0.8 m to the top of the pipe.

Overhead gas pipelines:

Overground gas pipelines, depending on the pressure, should be laid on supports made of non-combustible materials or along the structures of buildings and structures in accordance with the table.

Transit laying of gas pipelines of all pressures along the walls and over the roofs of buildings of children's institutions, hospitals, schools, sanatoriums, public, administrative and residential buildings with a mass presence of people is not allowed.

It is prohibited to lay gas pipelines of all pressures along the walls, above and below rooms of categories A and B, determined by fire safety standards, with the exception of hydraulic fracturing buildings.

In justified cases, transit laying of gas pipelines not higher than average pressure with a diameter of up to 100 mm is allowed along the walls of one residential building not lower than III degree of fire resistance of class C0 and at a distance of at least 0.2 m from the roof.

High-pressure gas pipelines should be laid along blank walls and sections of walls or at least 0.5 m above window and door openings of the upper floors of industrial buildings and administrative and residential buildings interlocked with them. The distance from the gas pipeline to the roof of the building must be at least 0.2 m.

Low and medium pressure gas pipelines can also be laid along the bindings or imposts of non-opening windows and cross the window openings of industrial buildings and boiler rooms filled with glass blocks.

The height of the overhead gas pipelines should be taken in accordance with the requirements of SNiP II-89.

On pedestrian and road bridges built of non-combustible materials, it is allowed to lay gas pipelines with a pressure of up to 0.6 MPa from seamless or electric-welded pipes that have passed 100% inspection of factory welded joints by physical methods. The laying of gas pipelines on pedestrian and road bridges built of combustible materials is not allowed. 10

Chapter 2 Natural and socio-economic conditions of the Zubtsovsky district

2.1 Natural and ecological conditions

Zubtsovsky district was formed in July 1929 on the territory of the former Zubtsovsky district. The city of Zubtsov is one of the oldest cities in the Tver region. Zubtsov was first mentioned in the Novgorod Chronicle as a city in 1216. With the construction of the Vyshnevolotsk water system at the beginning of the 18th century, the Zubtsov became an important staging post on the waterway to St. Petersburg.

In 1708 - 1727 Zubtsov was part of the Petersburg province, and in 1727 -1775. - to Novgorodskaya. Since 1775 - the county town of the Tver governorate.

In 1780, the coat of arms of the city of Zubtsov was established: a fortress wall is depicted on a red background - a symbol of the border fortress.

The city of Zubtsov was famous for its fairs and bazaars. The main place in the fair trade was occupied by flax, flaxseeds, cattle, unworked sheepskin, leather, and earthenware.

At the end of the 19th century, the town of Zubtsov was a major center for the flax trade. Flax growing was developed throughout the entire area of the county and ranked first among other counties in the province.

At the beginning of the 20th century, the Moscow-Rybinsk railway passed through the Zubtsov. In terms of the convenience of communication lines, the Zubtsovsky district occupied a very advantageous position.

In Soviet times, the city of Zubtsov continued to develop as the center of an agricultural region, adhering to the flax-growing direction. Currently, the city of Zubtsov is a city of regional subordination, a regional center.

Zubtsovsky District is located in the southwestern part of the Tver Region. The length of the region from north to south is 40 km, from west to east about 70 km.

The district borders: in the west with the Rzhevsky district, in the north with Staritsky, in the east with the Shakhovsky district of the Moscow region, in the south with the Gagarinsky district of the Smolensk region (see Fig. 1). The region is located almost in the very center of the Russian plain. The relief of the area is a slightly hilly plain, but the tops of the hills are smoothed out. The Upper Volga Lowland enters the plain along the Volga River. The general slope of the terrain is directed towards the Volga River. The soils are represented by loams and sands.

Figure 1 - Zubtsovsky district.

The soils in the Zubtsovsky region are mainly soddy-medium-podzolic, only south of the town of Zubtsov there is a distribution of soddy-strongly podzolic soils, and small areas of highly podzolic soils are located to the west and north of the city.

The climate of the region is moderately continental. Winters are moderately mild, snowy enough; summers are moderately cool and humid.

Industrial enterprises, cultural institutions, residential areas have grown here. Automobile and pedestrian bridges have been built across the Volga, Vazuzu, Sheshma rivers.

The territory of the district covers an area equal to 2166.5 square meters. km. The municipal formation "Zubtsovsky District of the Tver Region" includes the municipal settlement of the city of Zubtsov and 7 rural settlements (Vazuzskoye, Dorozhaevskoye, Zubtsovskoye, Knyazhiegorskoye, Pogorelskoye, Stolipinskoye and Ulyanovskoye).

The Moscow-Riga railway passes through the territory of the Zubtsovsky district (through the regional center of Zubtsov). Within the boundaries of the district there are highways of international importance: Moscow-Riga, for more than 70 km., Of interregional importance: Zubtsov-Vyazma, Zubtsov-Gagarin. The length of local roads is 222.0 km, of which 218.2 km with hard surface, 3.8 km with unpaved surface.

The distance from the regional center of Zubtsov to the regional center of Tver is: by rail (through the city of Torzhok) 202 km, by road (through the city of Rzhev) 164 km, by water transport 153 km, by air transport 110 km.

An extensive network of social enterprises has been created in the region: there are 21 general education schools with 3 thousand students, 3 hospitals with 150 beds, an orphanage with 140 pupils, and cultural institutions.

The population of the area on September 20, 2011 - 17.7 thousand people, including: Zubtsov - 6.9 thousand people. eleven

Gas distribution networks. Device and equipment

PROSPECTS FOR DEVELOPMENT OF THE GAS INDUSTRY

The oil and gas industry will play a role in providing the industry with high-quality fuel for a long time to come. The delivery of fuel to consumers is accomplished in a variety of ways. The main type of delivery is pipelines. At the same time, trunk and transport pipelines are distinguished. Trunk lines make up almost half of the total length of pipelines and are mounted with pipes with a diameter of 1220 and 1420 mm.

Trunk gas pipelines are a complex of structures: gas pipelines themselves, compressor stations ( KS) for pumping gas and gas distribution stations ( GDS). Compressor stations are located at a distance of 120-150 km from one another, provide gas supply with an excess pressure of up to 5 MPa to GDS, which are the head facilities when gas is injected into the settlement. On the GDS the gas passes through filters, pressure regulators and is odorized (where strong-smelling substances are fed to the gas). More pressure than gas supplied from GDS in gas distribution networks, usually does not exceed 1.2 MPa. Typically, gas trunklines are built in several lines. To increase their throughput capacity, they are designed at 7.5 MPa.

Due to the seasonal irregularity of gas storage, it becomes necessary to store it. For this, various storage facilities are used: depleted gas and oil fields, or accumulating capacities of the last section of the main pipeline.

Physicochemical properties of oil and gases

Natural gases are divided into three groups: gases that are produced from purely gas storage facilities and consist mainly of methane (82-98%), gases that are obtained from condensate storage facilities of broad fractions (gasoline, ligruin, kerosene, and sometimes diesel oil, methane to 80-95%) and gases that are produced together with oil from oil storage tanks (30-70% methane).

The main parameters of gases include: density, specific gravity, mass and volumetric flow rates, linear and mass velocity, pressure, viscosity, humidity. Heat capacity, thermal conductivity and its throttling are distinguished from thermodynamic properties, i.e. a sharp decrease in pressure during expansion and a change in temperature.

For oils the following parameters are distinguished: evaporation, saturated vapor pressure above the surface, density, viscosity, coefficients of thermal conductivity, thermal expansion and heat capacity, flammability, ignition temperature and explosiveness of self-ignition, toxicity.

Gas distribution networks. Device and equipment

Depending on the working pressure (MPa), gas distribution networks (SNIP 2.04.08-87) "Gas Supply" are subdivided into gas pipelines:

Residential and public buildings and small utility companies are connected to low-pressure gas pipelines. Medium and high pressure gas pipelines of category 2 with an overpressure of up to 0.6 MPa are used to supply low pressure gas distribution networks through gas distribution points ( Hydraulic fracturing), as well as large gas consumers (industrial enterprises, bakeries, baths, etc.)

According to the number of pressure levels used in gas networks, gas supply systems are divided into two-stage, three-stage and multi-stage. The applied scheme is determined by the type of consumer. Gas control points ( Hydraulic fracturing- for power supply of separate networks) and gas distribution units ( GRU- for feeding individual consumers) are usually located in separate buildings. Besides Hydraulic fracturing and GDS gas supply systems have gas distribution stations ( GDS), which regulate the supply of gas from the main pipelines to consumers.

External and underground laying of pipelines is carried out taking into account climatic conditions, the depth of soil freezing, the presence of electrical wiring, other pipelines, a slope - for the possibility of draining condensate, lens compensators for temperature stresses.

A gas distribution network is a system of pipelines and equipment used to transport and distribute gas within a city or any other settlement. In addition to gas pipelines, the main equipment of the gas distribution network is gas control points (GSP), which serve to reduce pressure and maintain it at a given level. Gas networks also include gasholders or gasholder stations that serve to receive gas from gas supply sources during the hours of minimum gas consumption and to deliver gas to the distribution network during peak hours, when the capacity of the sources is insufficient to cover the gas consumption. Gas tanks are usually located near gas distribution stations or at factories. Gas tanks have not been built recently. Internal gas equipment includes courtyard and internal gas pipelines of residential buildings, utilities and industrial enterprises, as well as gas installations and appliances for using gas.

The main equipment of the gas distribution network are gas control points (GSP), which serve to reduce the gas pressure and maintain it at a given level.

The connections are made using short connections to the gas distribution network, such as condensate risers. For short-term measurements, reinforced concrete structures, steel piles of fences and pipelines can be used as anode grounding conductors. When using railway structures, a cautious approach is recommended due to the possible connection to signaling systems. Resistance to current spreading from these objects should be as low as possible less than 1 Ohm. The superimposed current should be as high as possible.

In many cases, such as when calculating gas distribution networks and in-house gas pipelines, it is quite possible to use not basic equations in general form, but particular formulas obtained on the basis of these equations. To obtain partial calculation formulas, instead of the resistance coefficient X, substitute the expression of its functional dependence on other parameters that can be easily determined in the basic equations.

Depending on the number of stages of pressure reduction in gas pipelines, gas supply systems of settlements are one-, two- and three-stage:

1) one-stage (Fig. 16.5 a) is a gas supply system in which gas is distributed and supplied to consumers through gas pipelines of only one pressure (usually low); It is used in small settlements;
2) a two-stage system (Fig. 16.5 b) ensures the distribution and supply of gas to consumers through gas pipelines of two categories: medium and low or high and low pressure; it is recommended for settlements with a large number of consumers located on a large territory;
3) three-stage (Fig. 16.5 c) is a gas supply system, where the supply and distribution of gas to consumers is carried out through gas pipelines of both low, medium and high pressure; It is recommended for large cities.

Low pressure gas pipelines are mainly used to supply gas to residential buildings, public buildings and public utilities.

Gas pipelines of medium and high (up to 0.6 MPa) pressure are designed to supply gas to low pressure gas pipelines through urban hydraulic fracturing stations, as well as to supply gas to industrial and large utilities.

Gas pipelines of high (more than 0.6 MPa) pressure supply gas to industrial consumers, for whom this condition is necessary according to technological requirements.

When two- and three-stage gas supply systems are used, additional gas reduction is performed at gas control points (GSP). According to the purpose of the gas supply system, there are distribution gas pipelines, gas pipelines-inputs and internal gas pipelines. Distribution gas pipelines provide gas supply from gas supply sources to gas pipelines-inputs. Gas pipelines inlets connect gas distribution pipelines with internal gas pipelines of buildings. An internal gas pipeline is called a gas pipeline running from a gas pipeline to the point of connection of a gas appliance, a heating unit, etc.

By location in settlements, external (street, intra-quarter, courtyard, inter-workshop, inter-village) and internal (intra-workshop, intra-house) gas pipelines are distinguished.

By location relative to the surface of the earth, underground and aboveground gas pipelines are distinguished. According to the material of the pipes, gas pipelines are distinguished between metal (steel, copper) and non-metal (polyethylene, asbestos-cement, etc.). Connection and disconnection of individual sections of gas pipelines and gas consumers is carried out using stop valves - valves, taps, valves. In addition, gas pipelines are equipped with the following devices: condensate traps, lens or flexible expansion joints, control and measuring points, etc.

Page 1

The gas distribution network should provide minimum material and capital investments, as well as minimum operating costs.

A gas distribution network is a system of pipelines and equipment used for the transport and distribution of gas in settlements.

A gas distribution network is a pipeline system for equipment used for the transport and distribution of gas in settlements.

A gas distribution network (GDS) is a system of pipelines and equipment used for the transport and distribution of gas in settlements. Gas is supplied to the GDS from the main gas pipeline through the gas distribution station.

For gas distribution networks, a sudden failure is most typical, since the loss of tightness by the pipe usually occurs in an abrupt manner.

For gas distribution networks, a loaded or lightweight reserve is characteristic. When the networks operate in a mode other than the calculated one, it can be assumed that almost any section performs the functions of a lightweight reserve. In hydraulic fracturing, boiler houses and other gas-consuming facilities, all types of reserves can take place.

The calculation of the gas distribution network is reduced to the calculation of the diameters of the network sections and the pressure at the nodal points.

Gas distribution pipelines are in difficult operating conditions, are subject to prolonged exposure to constant static load, the danger of corrosion damage, and are subjected to cyclic loading; local stress concentrators can occur, as well as hardened sections of the heat-affected zone of welded seams. The conditions of long-term operation create the preconditions for the processes of delayed destruction of the pipe metal.

The gas distribution network option should provide minimal material and capital investments, as well as minimal operating costs.

A polar organic corrosion inhibitor is used in the gas distribution network transporting acidic gas with an admixture of hydrogen sulfide. For this, a 25% solution of the inhibitor in kerosene is pumped continuously into the compressor discharge line through the nozzle of the diesel injector, ensuring the protection of the distribution network with a gas consumption of 283 liters per day.

Gas distribution networks include gas pipelines intended for the transportation of gas in cities and towns: for supply to residential buildings, public service establishments, enterprises and other consumers. The gas distribution network is a system of pipelines and equipment, which includes both city trunk pipelines designed to transfer gas from one area of the city to another, and distribution gas pipelines for supplying gas directly to consumers. From the GDS it is sent to the gas control points (GRP) installed on the city network. Gas control points are designed to reduce gas pressure; they combine gas pipelines of various pressures. Depending on the pressure of natural gas, city pipelines are divided into low, medium and high pressure gas pipelines.

Gas gathering and gas distribution networks also include gas pipelines of underground gas storage facilities, which provide injection and withdrawal of gas.

Consumers are directly connected to low-pressure gas distribution networks. At the same time, the connection of subscribers through the regulators does not introduce fundamental changes to the schemes of gas networks.

Consumers are connected directly to low-pressure gas distribution networks. The number of hydraulic fracturing units feeding the low pressure network is determined by a technical and economic calculation. Gas control points are located in the centers of the zones that they supply. The coverage area of one hydraulic fracturing unit should not overlap the coverage area of another.

On gas distribution networks receiving gas from one regional gas control station, the need to install such pressure gauges should be determined by the operating company.

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MINISTRYEDUCATIONANDSCIENCESRUSSIANFEDERATIONS

NOVEMBERINSTITUTEOILANDGAS

(BRANCH)FEDERALSTATE BUDGETEDUCATIONALINSTITUTIONSHIGHERPROFESSIONALEDUCATION

"TYUMENSKYSTATEOIL AND GASUNIVERSITY "

(BranchTyumGNGU)

Topic: Gas distribution networks

Introduction

3. Gas pipelines

3.1 Underground gas pipelines

3.2 External gas pipelines

3.3 Aboveground gas pipelines

Conclusion

Introduction

GAS DISTRIBUTION NETWORKS - a system of pipelines for transportation and distribution of gas at facilities.

Gas in high-pressure gas distribution networks is supplied from the main gas pipeline through a gas distribution station, and into medium and low pressure gas distribution networks through gas distribution points. According to their purpose, gas pipelines of gas distribution networks are distinguished: main city and inter-settlement ones - run up to the head gas distribution points; distribution (street, intra-quarter, inter-workshop, etc.) - from gas distribution points to inputs; inputs - from the point of connection to the distribution gas pipeline to the disconnecting device at the entrance to the building; input gas pipelines - from the disconnecting device; internal gas pipelines - from the inlet gas pipeline to the point of connection of the gas appliance.

Gas pipelines of gas distribution networks are of low (up to 0.005 MPa), medium (from 0.005 to 0.3 MPa), high (from 0.3 to 0.6 and from 0.6 to 1.2 MPa) pressures. The nature of power supplies and the configuration of gas distribution networks are determined by the volume of gas consumption, structure, building density, etc.

1. Gas distribution network

The main equipment of the gas distribution network are gas control points (GSP), which serve to reduce the gas pressure and maintain it at a given level.

Depending on the number of stages of pressure reduction in gas pipelines, gas supply systems of settlements are one-, two- and three-stage:

1) one-stage (Fig. 16.5 a) is a gas supply system in which gas is distributed and supplied to consumers through gas pipelines of only one pressure (usually low); It is used in small settlements;

2) a two-stage system (Fig. 16.5 b) ensures the distribution and supply of gas to consumers through gas pipelines of two categories: medium and low or high and low pressure; it is recommended for settlements with a large number of consumers located on a large territory;

3) three-stage (Fig. 16.5 c) is a gas supply system, where the supply and distribution of gas to consumers is carried out through gas pipelines of both low, medium and high pressure; It is recommended for large cities.

Low pressure gas pipelines are mainly used to supply gas to residential buildings, public buildings and public utilities.

Gas pipelines of high (more than 0.6 MPa) pressure supply gas to industrial consumers, for whom this condition is necessary according to technological requirements.

By location in settlements, external (street, intra-quarter, courtyard, inter-workshop, inter-village) and internal (intra-workshop, intra-house) gas pipelines are distinguished.

2. Gas distribution stations

Gas distribution station (GDS) - a set of installations and technical equipment, measuring and auxiliary systems for gas distribution and regulation of its pressure. Gas distribution stations are included in gas distribution systems. A distinction is made between: gas distribution stations proper, built at the end points of main gas pipelines or gas pipelines departing from them with a capacity of up to 500 thousand cubic meters per hour; field gas distribution stations; control and distribution points; gas control points; automatic gas distribution stations.

Field gas distribution stations are used to process gas produced in the fields, as well as to supply gas to a settlement nearby to the field, control and distribution points - to industrial or agricultural facilities, as well as to power the ring system of gas pipelines built around the city. Automatic gas distribution stations supply gas to small settlements, state farms and collective farms on branches from main gas pipelines.

The gas distribution stations include the main units: disconnecting devices; gas cleaning; prevention of hydrate formation (if necessary); automatic reduction (pressure regulation, gas flow measurement); automatic odorization of gas. Gas from the inlet gas pipeline enters the block of shut-off devices and is sent for cleaning to oil dust collectors or viscous filters of the cleaning unit, then enters the automatic pressure control unit. Further, the gas is directed to the low pressure outlet gas pipelines, where the flow rate is measured, quantified and odorized. The number of reduction lines at gas distribution stations depends on the gas flow rate; one of the lines is envisaged as a backup. Automated gas distribution stations are supplied with a set of shut-off valves, which, in an emergency, provide automatic commissioning and shutdown of working and reserve reduction lines.

gas distribution network station pipeline

3. Gas pipelines

3.1 Underground gas pipelines

Gas pipelines of this kind are mainly laid along city thoroughfares, as well as in the area of green spaces. Horizontal distances between underground gas pipelines and other structures must be observed in accordance with the requirements.

When a gas pipeline crosses a tramway or when a gas pipeline is forced across a channel, cases made of steel pipes are used, at the ends of which control tubes are installed.

Gas pipelines are made of steel pipes, connecting them with electric welding. In places where gas appliances, fittings and other equipment are installed, flange and threaded connections are used. To protect steel pipes from corrosion, they are insulated before being buried in the ground.

The depth of the gas pipelines depends on the composition of the transported gas. With wet gas, the pipe laying depth is taken below the average depth of soil freezing for a given area. Dried gas pipelines can be laid in the soil freezing zone, but the deepening must be at least 0.8 m from the earth's surface. Gas pipelines are laid with a slope of at least 1.5 mm / linear. m, which ensures the removal of condensate from the gas into the condensate traps and prevents the formation of water plugs.

To turn off individual sections of the gas pipeline or disconnect consumers, shut-off valves are installed, placed in the wells.

When the temperature conditions change, tensile forces appear on the gas pipeline, which can rupture the welded joint or valve. To avoid this, lens compensators are installed on gas networks and, in particular, on valves, which absorb these forces. In addition to the perception of thermal deformations, expansion joints make it easy to dismantle and replace valves and gaskets, since the expansion joint can be compressed or stretched with the help of special devices. Lens expansion joints are installed in the same well with the valves, and they are located after the valves, counting along the gas flow.

Low pressure gas pipelines (up to 5000 Pa) can be laid in underground collectors together with other utilities. They can also be laid in semi-passages between residential and public buildings (in "couplings" for joint laying of engineering networks). Through and semi-through channels must be equipped with permanent natural ventilation. Laying gas pipelines in non-passable channels together with other pipelines and cables is unacceptable.

When laying several gas pipelines in one trench, the distance between them in the light should be at least 0.4 m with a pipe diameter of up to 300 mm and at least 0.5 m with a diameter of more than 300 mm.

On gas pipelines with a diameter of 100 mm or less, flexible expansion joints are installed in the wells. When condensate accumulates in gas pipelines, the normal gas flow is disrupted. Condensate collectors are used to drain condensate from low points of the gas network, which are installed in low, medium and high pressure networks. In the first case, the condensate is pumped out by a pump; in the second case, it is removed under gas pressure.

3.2 External gas pipelines

External gas pipelines are the most important element of any gas supply system, important not so much in their importance as in the consequences that arise when gas pipelines fail. At best, this leads to disruption of gas supply to consumers, at worst - to an emergency situation, destruction and destruction of material assets, accidents and casualties among people.

The laying of external gas pipelines, regardless of the purpose and gas pressure, should be provided, as a rule, underground along the streets and roads of cities and towns. This type of laying is dictated by considerations of the improvement of the city. Above-ground laying of gas pipelines is provided mainly on the territory of industrial and municipal enterprises and inside residential areas and courtyards. Underground laying of gas pipelines along city streets is associated with significant difficulties, especially in those cases when the construction of a gas pipeline must be carried out in the conditions of existing buildings.

For external gas pipelines, pipes made of well-weldable low-carbon and low-alloy steels with a carbon content of not more than 0.27% and a minimum relative elongation of at least 18% for five-fold samples should be used. It is allowed to use imported pipes that do not have certificates, but in terms of chemical composition and mechanical properties meet the above requirements.

Maintenance of external gas pipelines consists in monitoring their condition, as well as the state of the environment surrounding the gas pipeline by bypassing the routes. The detour is performed by a team of two linemen, one of whom is the senior. All work on the maintenance of underground and aboveground gas pipelines must be carried out in accordance with the approved instructions within the time frames provided for by the gas service of the enterprise (responsible for the gas economy) and approved by the management of the enterprise. The timing of bypassing gas pipelines should be reviewed annually, taking into account changes in operating conditions and accumulated experience.

External gas pipelines include city trunk pipelines, distribution pipelines, which can be underground (underwater) or aboveground (surface), and inputs.

On external gas pipelines, flange connections are used only for installing valves, taps and other fittings. Threaded connections are used in places where taps, plugs, couplings on condensate traps and hydraulic locks are installed, valves on overhead inlets of low-pressure gas pipelines and instrumentation connections. On internal gas pipelines, flange and threaded connections are allowed only for connecting shut-off valves, instrumentation and equipment. Detachable connections must be accessible for inspection and repair.

When installing external gas pipelines, pipes with an inner diameter1 of 100 to 400 mm are most often used, but large diameter pipes are used to build the main gas pipelines. Gas pipelines in buildings are laid from pipes with a diameter of at least 13 mm, and underground gas pipelines - at least 38 mm.

3.3 Aboveground gas pipelines

Aboveground gas pipelines laid in places where air contaminated with corrosive gases or vapors of corrosive liquids is emitted from workshops must have a protective coating against corrosion, which can be caused by these substances.

Aboveground gas pipelines should be designed taking into account the compensation of longitudinal deformations according to the actually possible temperature conditions of operation and, if necessary (when self-compensation is not provided), provide for the installation of expansion joints. The use of stuffing box expansion joints is not allowed. The height of the gas pipeline should be assigned subject to the provision of inspection and repair. It is not allowed to provide flange or threaded connections on gas pipelines under window openings and balconies of buildings. Gas pipelines laid along the outer walls of buildings, overpasses, supports, as well as risers at the exit from the ground, if necessary, must be protected from mechanical damage.

Overhead gas pipelines transporting wet gases must be laid with a slope of at least 3 mm per 1 linear meter. Periodic and continuous water traps are installed on artificial gas pipelines. From the first, the accumulated moisture is removed during purging, from the second it is discharged automatically as it is filled through the siphon tube. To prevent cooling, causing the release of moisture and its subsequent freezing, gas pipelines and their fittings are covered with thermal insulation. In areas with stable low temperatures, the gas pipeline is insulated together with the steam pipeline.

Aboveground gas pipelines are tested for tightness after elimination of all defects found during the strength test. A test pressure is set in the gas pipeline and held for less than 30 minutes, after which, under the same pressure, all welded, flanged, threaded and gland joints are inspected with a soap emulsion. In the absence of a visible pressure drop on the pressure gauge and air leaks, the gas pipeline is considered to have passed the test.

Aboveground gas pipelines are laid on reinforced concrete and metal columns, and underground ones are laid in trenches dug into the ground. An underground gas pipeline is usually less expensive to build than an aboveground one, but aboveground gas pipelines are much easier to repair.

Aboveground gas pipelines are accessible for inspection and repair and are safer and therefore preferred. Shop pipelines are carried out only above ground, which ensures their good inspection and the necessary safety of personnel. Gas pipelines are constructed, tested and operated in strict compliance with the technical rules developed by Gosgortekhnadzor.

Aboveground gas pipelines of all pressures are considered to have passed the density test if there is no visible pressure drop on the pressure gauge and no air leaks when checking the connections by soaping after 30 minutes of keeping the gas pipeline under pressure. This must be verified by external inspection of the gas pipeline and checking with soapy water all welded, flanged and threaded connections.

Aboveground gas pipelines should be protected from atmospheric corrosion by a coating consisting of two layers of primer and two layers of paint, varnish or enamel, intended for outdoor use at the design temperature of the outside air in the construction area.

Aboveground gas pipelines after cleaning must be primed and painted with oil paint: oxygen pipelines - blue, acetylene pipelines - white, pipelines of other combustible gases - red; underground ones should be covered with anti-corrosion insulation.

Aboveground gas pipelines are allowed to be laid along the same route with other pipelines with a clear distance to the nearest pipeline of at least 250 mm.

After cleaning, aboveground gas pipelines should be primed and painted with oil paint: oxygen pipelines - blue, acetylene pipelines - white, hydrogen pipelines - green, and pipelines of other combustible gases - red. In case of thermal insulation, the gas pipeline is painted on the outer fabric pasting of the insulation. Thermal insulation must be made of non-combustible materials. Aboveground gas pipelines laid in places where air contaminated with corrosive gases or vapors of corrosive liquids is emitted from workshops must have a protective coating against corrosion, which can be caused by these substances. Aboveground gas pipelines transporting wet gas are laid with a slope of 0 003 with the installation of condensate removal devices at the lowest points. After the test, an external examination and a soapy solution of all welded, flanged and threaded connections are carried out. The gas pipeline is considered to have passed the test in the absence of a fall on the pressure gauge and air leaks during soaping. The rise and fall of pressure during the test should be done smoothly. It is prohibited to eliminate defects until the pressure in the gas pipeline is reduced.

Aboveground gas pipelines transporting wet gas are laid with a slope of 0 003 with the installation of condensate removal devices at the lowest points. After the test, all welded, flanged and threaded joints are visually inspected and with a cleaning solution. The gas pipeline is considered to have passed the test when there is a drop on the pressure gauge and air leaks during soaping: The rise and fall of pressure during the test should be carried out smoothly. It is prohibited to eliminate defects until the pressure in the gas pipeline is reduced. Aboveground gas pipelines transporting wet gas are laid with a slope of 0 003 with the installation of condensate removal devices at the lowest points. Aboveground gas pipelines must be painted or have an anti-corrosive coating. Aboveground gas pipelines are tested for tightness for 30 minutes. After the test, an external examination and a soapy solution of all welded, flanged and threaded connections are carried out. The gas pipeline is considered to have passed the test in the absence of a pressure drop on the pressure gauge and air leaks during soaping. The rise and fall of pressure during the test should be done smoothly. It is prohibited to eliminate defects until the pressure in the gas pipeline is reduced. Above-ground gas pipelines in places where air contaminated with corrosive gases or vapors of liquids is emitted from workshops must have a protective coating against corrosion. Aboveground gas pipelines must be protected against corrosion by oil paint, varnish or other coatings that can withstand temperature changes and the effects of atmospheric precipitation.

Conclusion

The routes of gas distribution networks are designed taking into account the provision of a minimum length of pipelines. Gas distribution networks are made dead-end and circular with duplication of individual elements (to increase the reliability of gas supply). Annular gas pipelines are given an elongated shape, elongated in the direction of the main flow of the supplied gas. Hydraulic operating modes of gas distribution networks are taken from the conditions for ensuring the stable operation of gas control points and installations, as well as burners of municipal and industrial consumers at the maximum permissible gas pressure drops.

List of used literature

1. Lutoshkin G. C. Pipeline transport of oil and gas, 1978.

2. Bunchuk B. A. Transport and storage of oil products and gas, 1977.

3. Korshak A.A. A.M. Nechval Design and operation of gas and oil pipelines, 2008.

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Gas distribution networks. Device and equipment

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