Coursework. Gas supply to the microdistrict of Volgograd

Contents

Modern city gas supply distribution systems are a complex complex of structures, consisting of the following main elements of low, medium and high pressure gas networks, gas distribution stations (GRS), gas control points (GRS) and plants (GRU). To manage the operation of this system, there is a special service with appropriate means to ensure the possibility of uninterrupted gas supply

Gas supply projects of regions, cities and towns are developed on the basis of schemes of promising gas flows, schemes for the development and placement of sectors of the national economy and projects of district plans, master plans of cities taking into account their development for the future. The gas supply system shall ensure uninterrupted gas supply to consumers, be safe in operation, simple and easy to maintain, shall provide for the possibility of disconnecting individual elements or sections of the gas pipeline for repair and emergency works

The main element of urban gas supply systems are gas pipelines, which are classified by gas pressure and purpose. Depending on the maximum gas pressure, city gas pipelines are divided into the following groups:

- low-pressure gas pipelines with gas pressure up to 5 kPa;

- medium pressure gas pipelines with pressure from 5 kPa to 0.3 MPa;

- high-pressure pipelines of category II with pressure from 0.3 to 0.6 MPa;

- high-pressure pipelines of category I with gas pressure from 0.6 to 1.2 MPa

Low-pressure gas pipelines serve to transport gas to residential, public buildings and consumer services

Medium and high (II category) pressure pipelines are used for supply of urban low and medium pressure distribution networks through FRG

High-pressure (I category) city gas pipelines are the main arteries feeding a large city, they are made in the form of a ring, half-ring or in the form of rays

In this course project, it is necessary to select and calculate the city, quarter and house gas supply system, as well as the selection of GRU equipment and the calculation of the burner for the boiler of the quarter boiler room according to the initial data

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Urban Area Plan

The city of Volgograd. Romashikhinskoye field

Location of medium pressure consumers: GRS for 12 hours, Plant 1-for 3 hours, Plant 2-10 hours, Bakery for 12 hours

Coverage of consumers with gas in 1-2 storey buildings 75%

Plant 1 - Chunnolitheic (V-1526 Tj/year P = 230 kPa); Plant 2 - seam factory (V-260 Tj/year P = 185 kPa);

7. Gas pressure at bakery inlet - 160 kPa;

8. Gas pressure at bath and laundry plant inlet - 180 kPa;

9. Pressure at inlet to FRG - 220Kpa

10. Soil corrosive activity - high

11. HSV water heater type

12. We take the building design from the course project "Heating"

We adopt a two-stage scheme for gas supply to the city, since medium and low pressure gas is used. Medium pressure gas distribution networks transport gas from gas distribution station to medium pressure consumers and PRG. In PWG, the gas pressure is reduced to low and through low pressure distribution networks the gas is directed to low pressure consumers. When designing gas distribution networks, it is necessary to take into account the requirements for external gas pipelines

The route of medium-pressure gas distribution networks is selected taking into account the layout and development from GRS to medium (or high) pressure consumers: industrial enterprises, large utilities and PRG

It is recommended that the location of the PRG on the master plan of the city be provided evenly. PRGs are located in the center of the area served by

When selecting the route of the low pressure city distribution gas network, it is recommended to loop the main gas pipelines. The ring scheme is expedient in areas of multi-storey development. The use of a dead end gas distribution scheme is also allowed. In a ring scheme, it is recommended that the ring dimensions be taken depending on the density of the gas load. It is recommended to perform two-way gas extraction from sections of low pressure gas distribution network. It is advisable to lay gas pipelines along streets and driveways that are low and not saturated with underground communications. The laying of gas pipelines parallel to the more elongated sides of the quarters allows to reduce the length of intra-quarter gas pipelines

In the city, it is recommended to lay underground gas pipelines from polyethylene pipes. Depth of laying depends on properties of transported gas, soil properties, ground water level. Parallel laying of gas pipelines of different pressure categories in one trench at one or different levels is possible. It is recommended to provide gas valves in the above-ground design or in the underground design. Since the gas pipeline route should be located at a certain distance from the development lines, it is advisable for other utilities to lay underground gas pipelines under the sidewalks, in technical dividing lanes along the driveways and streets. It is advisable to lay a highway along streets and driveways that are small and unsaturated by underground communications

The risk of soil corrosion of underground metal gas pipelines is determined by the corrosive aggressiveness of soils to the metal of the gas pipeline in accordance with GOST 9.602-

For gas pipelines laid directly in the ground within the territories of cities and industrial enterprises, coatings of a very reinforced type are used. And also for gas pipelines with a pressure of 1.2 MPa laid outside urban areas

When laying the above-ground gas pipeline, the requirements of SP 28.13330 are met with anti-corrosion pipe coating consisting of 2 layers of primer and 2 layers of enamel

The risk of soil corrosion of underground metal gas pipelines is determined by the corrosive aggressiveness of the soil to the metal

Specific electrical resistance of the soil UES = 7 Ohm * m, the degree of corrosion activity of the soil is high. Insulation type - Highly reinforced and cathodic. Anti-corrosion insulation is used in metal areas at the entrance to the building, and in areas where reinforcement is located. Insulation consists of primer, three layers of reinforced bitumen mastic and Kraft paper, total insulation thickness is 9mm

The gas distribution system of the quarter provides gas to low-pressure consumers. The quarter's gas pipelines join the city's low-pressure gas distribution networks and transport gas to residential buildings and other small public utilities

5.1. Selection of gas distribution system of the quarter

When selecting the gas distribution network of the quarter, a dead end network with redundancy of gas pipelines supplied from various sections of the city gas distribution network of low pressure is recommended

Underground laying of gas pipelines is recommended. Gas distribution networks are made of SDR 17.6 polyethylene pipes. On the last sections along the gas flow, it is possible to provide for facade laying of gas pipelines from metal pipes GOST 3262-75. The distance from underground low-pressure gas pipelines to the foundations of buildings must be at least 2 m. It is forbidden to provide laying under buildings and in the basements of buildings. When crossing with utilities, it is necessary to observe standard distances, the gas pipeline is laid in the case

Shut-off devices are installed on the branch at the number of subscribers more than 400, at the gas pipeline inlet to the quarter. It is recommended to provide above ground installation of disconnecting devices. Condensate collectors are installed on gas pipelines of associated and liquefied gas in lower points

5.4. Development of material and equipment specification for the distribution gas network of the quarter

A specification for gas pipelines and gas equipment is being developed for the gas distribution network of the quarter. The specification is given in the explanatory note. Piping and valves are included in the specification

The project provides for the development of internal gas pipelines of a residential building. We choose a typical floor plan for a residential building from the course project "Heating of a residential building"

6.2. Laying of internal gas pipelines

Laying of internal gas pipelines of residential buildings is carried out according to the requirements. Gas pipelines laid inside buildings and structures should be provided from steel pipes. For connection of mobile units, portable gas burners, gas devices, instrumentation and automation devices it is allowed to provide rubber and rubber-fabric hoses. Connection of pipes should be provided, as a rule, on welding. Split (threaded and flanged) connections may be provided only in places of installation of shutoff valves, gas instruments, instrumentation and other equipment

Installation of split connections of gas pipelines shall be provided in places accessible for inspection and repair

The laying of gas pipelines inside the buildings is provided open. In case of hidden gasket access to gas pipeline shall be provided

It is not allowed to provide for laying of gas pipelines in rooms belonging to categories A and B for explosion and explosion-fire hazard; in explosive areas of all premises; in basements; in warehouses of explosive and combustible materials; in substation and switchgear rooms; through ventilation chambers, shafts and channels; elevator shafts; rooms of garbage collectors; chimneys; through premises where the gas pipeline may be subject to corrosion, as well as in places where aggressive substances may be exposed and in places where the gas pipelines may be washed by hot combustion products or come into contact with heated or molten metal

The laying of gas pipelines in residential buildings should be provided for non-residential premises. In existing and reconstructed residential buildings, it is allowed to provide for transit laying of low-pressure gas pipelines through living rooms in the absence of the possibility of another gasket. Transit gas pipelines within residential premises shall not have threaded connections and fittings

It is not allowed to provide for the laying of gas pipeline risers in residential rooms and sanitary units

The installation of disconnecting devices on gas pipelines laid in residential buildings is provided: at the commissioning of the gas pipeline inside the premises; for disconnection of risers serving more than five floors; before counters (if you cannot use the switch-off device at the input to disable the counter); before each gas device

Installation of disconnecting devices on gas pipelines with their hidden and transit laying is not allowed

In a residential building in a room where gas-using equipment is located, it is necessary to provide a heat-intake valve in the upper part of the room on the gas pipeline. As well as a system for monitoring the gas content of rooms with automatic shutdown of gas supply in the following cases:

- at installed equipment power exceeding 60 kW (approximately 6.9 m3/h);

- when placing gas-using equipment in the basement, basement floors, in the annex to the building, regardless of thermal power

Gas pipelines at the intersection of building structures should be laid in cases. The space between the gas line and the case must be sealed with a ground pack, rubber sleeves or other elastic material. The end of the case shall project over the floor by not less than 3 cm, and its diameter shall be taken so that the annular gap between the gas pipeline and the case is not less than 5 mm for gas pipelines of nominal diameter not more than 32 mm and not less than 10 mm for gas pipelines of larger diameter

Internal gas pipelines are protected against corrosion in accordance with the requirements of SP 28.13330 with a coating consisting of 2 layers of primer and 2 layers of enamel

1. Introduction

2. Initial data

3. Determination of design characteristics of gas fuel used

4. Determination of gas consumption in the microdistrict

4.1. Calculation of low pressure gas consumers.

4.2.Annual heat consumption by industrial enterprises

4.3. Calculation of the optimal number of PRGs for the gas distribution system of the city

4.4. Choice of gas distribution system of city microdistricts

4.5. Design of low pressure urban distribution gas networks

4.6. Design of medium pressure urban gas distribution networks

4.7. Selection of PRG equipment

4.8. Selection of the type of anti-corrosion insulation

5. GAS DISTRIBUTION NETWORKS OF THE QUARTER

5.1. Selection of gas distribution system of the quarter

5.2. Design of LP quarterly distribution gas networks

5. 3. To Create a Gas Pipeline Profile

5.4.Development of material and equipment specification for the distribution gas network of the quarter

6. Internal gas pipelines of residential buildings

6.1. Location of gas-using equipment

6.2. Laying of internal gas pipelines

6.3. Calculation of internal gas pipelines

7. List of literature

8. Application.

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