Concept of gas supply to the microdistrict

Contents

Contents

Introduction

Main part

Gas supply conditions

Gas characteristics

Determination of the number of inhabitants in the microdistrict

Determination of the capacity of public utilities

Determination of annual gas expenditures for household and communal needs

Determination of estimated gas hourly flow rates

Selection and justification of gas supply system

Selection of gas control points

Routing Procedure for Low Pressure Distribution Gas Lines

Determination of Low Pressure Gas Design Flow Rates

Hydraulic calculation of low pressure distribution gas pipelines

Hydraulic calculation of medium pressure annular gas pipeline

Hydraulic calculation of yard gas pipeline

Conclusion

List of used literature

Introduction

Gas supply systems are a complex complex of structures. The choice of the gas supply system of the city is influenced by a number of factors. This, first of all: the size of the gasified territory, the features of its layout, population density, the number and nature of gas consumers. Availability of natural and artificial enterprises for laying gas pipelines (rivers, dams, ravines, railway tracks, underground structures, etc.).

When designing a gas supply system, a number of options are developed and their technical and economic comparison is made. As a final option, the most economical is taken, compared to others.

Gas supply systems of the district of the city or a small settlement, it is recommended to adopt a single-stage ring gas supply system.

All gas pipelines included in the gas distribution network are conditionally distributed to transit and distribution pipelines. Transit gas pipelines are designed to transfer gas from one area of ​ ​ a settlement to another. Distribution gas pipelines serve to supply gas directly to consumers.

On the basis of the master plan, the gas pipelines are laid out, the diagram indicates the design gas pipelines, their diameter, as well as the installed disconnecting devices.

This project is based on:

- tasks with initial data;

- scheme of Kamyshin microdistrict;

- General Plan of the Quarter

Main part

1.1 Gas supply conditions

Gas supply district - Kamyshin Volgograd region.

Gas Supply Source - Main Gas Pipeline

Gas pressure at tie-in point - 0.3 MPa

The gas supply system is two stages with gas supply to consumers through gas pipelines of two pressures - high and low. Gas pressure drops from high to low at gas control station. GRP is designed in the center of gas consumption load. High-pressure gas pipeline P = 0.6 MPa enters the FRG, and exits the low-pressure gas pipeline with P = 3000 Pa.

Consumers of residential buildings, health facilities, catering, trade and public services are fed from the low-pressure network.

Concentrated consumers are fed from the high-pressure network - boiler houses, a bath and laundry plant, a bakery and GRP.

1.7 Selection and justification of gas supply system

Gas supply systems are a complex complex of structures. The choice of the gas supply system of the city is influenced by a number of factors. This is primarily: the size of the gasified territory, the features of its layout, population density, the number and nature of gas consumers, the presence of natural and artificial obstacles to the laying of gas pipelines. When designing a gas supply system, a number of options are developed and their technical and economic comparison is made. For construction, the best option is used.

Depending on maximum gas pressure city gas pipelines

are divided into the following groups:

high pressure category 1 with pressure from 0.6 to 1.2 MPa;

medium pressure from 5 to 0.3 MPa;

low pressure up to 5 kPa;

High- and medium-sized gas pipelines serve to supply medium and low-pressure urban distribution networks. They are the bulk of the gas to all consumers of the city. They are made in the form of rings, semi-rings or rays. Gas is supplied to high-medium pressure gas pipelines from gas distribution stations.

Modern systems of urban gas networks have a hierarchical construction system, which is linked to the above classification

gas pipelines by pressure. The upper level consists of high-pressure gas pipelines of the first and second categories, and lower low-pressure gas pipelines. The gas pressure during the transition from a high level to a lower level gradually decreases. This is done using pressure regulators installed on the FRG.

According to the number of pressure stages used in urban networks, they are divided into:

single-stage gas supply of any one of the pressures;

two-stage, consisting of high or medium pressure and low pressure networks;

three-stage, including high, medium and low pressure gas pipelines;

multistage, in which gas is supplied through gas pipelines of high (1 and 2 categories) pressure, medium and low pressure.

The choice of the gas supply system in the city depends on the nature of gas consumers who need gas of the appropriate pressure, as well as on the length and load of gas pipelines. The more diverse gas consumers and the greater the length and load of gas pipelines, the more difficult the gas supply system will be.

In most cases, for cities with a population of 500 thousand people, the two-stage system is the most economically feasible. For large cities with a population of more than 1,000,000 people and the presence of large industrial enterprises, a three-stage or multi-stage system is preferable.

Considering all these factors for this scheme of the microdistrict, we adopt a two-stage system:

ring circuit for low pressure networks;

ring circuit for high-pressure networks.

1.8 Selection of gas control points

Gas fuel must be supplied to consumers at a certain pressure, depending on the conditions of its use, through this gas is supplied, through automatic control devices, which are called gas control points.

Of the total length of urban gas pipelines, usually 70 - 80% make up low-pressure gas pipelines and only 20 - 30% medium and high-pressure.

As a rule, the most profitable solution is the use of cabinet and block gas control points, which reduces the costs of construction, installation.

For the low pressure mains feed EMG, the optimum capacity is assumed to be between 1500 - 2000 m3/h, with an optimum range of 0.5 - 1 km.

For educational purposes, one GRP is accepted for installation, which we place in the load center of the gas supplied territory. GRP is selected according to the table of technical characteristics of GRP based on throughput capacity of 3508.67 m3/h of gas inlet pressure, 0.6 Pa. According to the given initial data, ITGASMBN/652 is accepted for installation.

Technical characteristics of ITGAZ-MBN/65-2 GRP:

Technical characteristics of ITGAZ-MBN GRP/65-1-B:

Controlled medium

Natural gas as per GOST 5542-87

Ambient temperature

-40 ° С + 80 ° С

Gas pressure regulator - manufacturer

MBN/65** Tartarini

Input pressure range, MPa

0,010,6****

Output pressure, kPa *

1,5-50***

Uneven regulation,%

±5

Connection dimensions, mm

inlet nozzle

outlet nozzle

100

150

Connection:

inlet/outlet

Welded/Welded

Overall dimensions, mm:

And

N

L

Weight, kg

800

1850

1400

450

1.9 Routing Procedure for Switchgears

low pressure gas pipelines

The low pressure gas pipeline shall be routed in accordance with the following conditions:

The distance from the GRP to the most remote points of the network should be approximately the same;

All quarters shall be supplied with gas on at least two sides;

It is necessary to determine the direction of gas flow from the FRG to the most remote points. The condition of the meeting point of gas flows, after which the gas does not go through the distribution gas pipeline, is called zero points;

It is necessary to take into account the issues of reducing metal consumption (that is, there should be no unnecessary areas).

Conclusion

As a result of the course project, the number of residents in the microdistrict was determined, the capacity of utility consumers, annual gas costs for household and communal needs were determined. The estimated gas hourly flow rates were also determined and the load on GRP 3508.67 m3/year was determined.

During the work on the course project, the scheme of gas supply to the microdistrict was selected and justified and the gas control point ITGAZMBN/652 was selected. Hydraulic calculation of low and medium pressure distribution gas pipelines and calculation of the yard gas pipeline was also carried out, which made it possible to select the diameters of gas pipelines.

As a result of the course project, I have mastered the relevant professional competencies:

PC 1.1. Design elements of gas distribution and gas consumption systems;

PC 1.2. Perform basics of calculation of gas distribution and gas consumption systems;

PC 1.3. Prepare material and equipment specification for gas distribution and gas consumption systems.

Batareev1.dwg