Gas supply of the city district - exchange rate

Contents

ASSIGNMENT FOR THE COURSE PROJECT

Introduction

Scope of work

1. Calculation of gaseous fuel characteristics

2. Determination of the population of the projected area of the city

3. Calculation of gas consumption

3.1. Determination of annual gas consumption

3.2. Determination of estimated gas hourly flow rates

3.3. Determination of specific gas hourly flow rates by development zones

4. Gas Network Routing

5. Determination of estimated gas flow rates in sections of ring gas pipelines

5.1. Procedure for calculation of low pressure ring networks

5.2. Determination of concentrated and specific gas travel costs for gas network circuits

5.3. Determination of Gas Travel Costs in Ring Sections

6. Hydraulic calculation of gas pipelines

6.1 Calculation of low pressure street distribution rings

6.2. Calculation of intra-quarter gas pipeline

6.3. Calculation of internal house gas pipeline

6.4. Calculation of medium and high pressure gas pipelines

Conclusion

List of literature

Introduction

The purpose of the course project is to consolidate theoretical material on the main issues of the course "Gas Supply" to acquire skills of independent work in the field of gas supply systems design and experience with reference and special literature.

In the design, it is necessary to develop a two-stage gas distribution system with the implementation of the first stage by medium (high) pressure gas pipelines. and the second - low pressure. From the medium (high) pressure network, consumers should design more concentrated: GRP, boiler room, bakery, bath, laundry. At the same time, the boiler room is located taking into account the "rose of the winds" for the designed area, and the bakery, bath and laundry are arbitrary. From the low pressure network, household and communal consumers are designed, the list of which is accepted according to SNiP 2.04.0887. The low pressure network must be designed as a ring .

Improvement, intensification and automation of technological processes led to the need to improve the quality of consumable heat carriers. Natural gas meets these requirements most than other fuels.

Modern city distribution systems are a complex complex of structures consisting of the following main elements: low, medium and high pressure gas networks, gas distribution stations, gas distribution points and installations. In the above stations and installations, the gas pressure is reduced to the required value and automatically kept constant. They have automatic safety devices that exclude the possibility of increasing gas pressure in networks above normal.

The gas supply system shall ensure uninterrupted gas supply to consumers, be safe in operation, simple and convenient to maintain, shall provide for the possibility of disconnecting its individual elements or sections of gas pipelines for emergency or repair work.

Recently, networks are being designed with structural and transport reserves in connection with the development of the city's gas supply system.

4. Gas Network Routing

Gas pipeline routes are designed according to the minimum length of the network. At the same time, high-pressure gas pipelines are trying to lay along the outskirts of the city, where there is a small population density and a smaller number of underground structures .

Low-pressure networks consist of street distribution gas pipelines, subscriber branches supplying gas to the building and internal gas pipelines that distribute gas between individual devices of the building. The density of distribution gas pipelines is accepted so that the length of subscriber branches before entering the buildings is 50100 m. Residential and public buildings, utility consumers, as well as small enterprises are connected directly to distribution gas pipelines.

To increase reliability of low-pressure networks ring. In low-pressure networks, it is advisable to ring only distribution gas pipelines, and make secondary (subscriber branches) dead end branched.

The number of gas control points (GRP) is determined by technical and economic calculation. EMG is located in the centers of the zones that they feed. The range of one GRP shall not be covered by the range of another GRP. Gas flow meeting points in a system with several GRP are assigned at the boundary of zones of neighboring GRP.

When designing multi-stage gas supply systems, the question arises about the economically optimal range of Ropt GRP. As the number of FRG increases, the cost of the low pressure network decreases, but the total cost of FRG increases, as well as the cost of the medium (high) pressure network that feeds the FRG.

The most economical is considered Ropt = 400800 m.

The amount of GRP is calculated as follows. The value is set and the optimal throughput capacity of one FRG is determined by the formula

m3/h.

Having determined the throughput capacity of one GRP, their number is calculated

piece.

GRP range means the mean straight distance from the GRP to the gas flow meeting point at the interface

l.

where F is the gasified area of ​ ​ the settlement, including the area of ​ ​ driveways, m2;

p - number of FRG, pcs.

After application of the low-pressure gas pipeline route, closed circuits are identified, which should form the main ring part of the network. These circuits direct the main transit flows. No transit flows are directed to areas representing the internal intersections of these circuits.

The supply point (EMG) is located in the center of the main circuits and so that gas flows are directed to consumers in the shortest possible way. Flow meeting points are located diametrically opposite to supply point.

Conclusion

In this course design, a two-stage gas distribution system was designed with the implementation of the first stage by high pressure gas pipelines, and the second - by low pressure. Concentrated consumers were designed from the high-pressure network. From the low-pressure network, household and utility consumers were designed. The low pressure network is designed ring, high - dead end. The number of EMG was determined by techno-economic calculation and is 2.

Hydraulic calculation of low pressure distribution networks, intra-quarter gas pipeline, internal gas pipeline and high pressure was carried out in order to select the diameters of gas pipelines and determine pressure losses in them. Diameters were selected according to (3, Appendix 5) or practical considerations. Gas speeds comply with the regulatory requirement.

I also fixed theoretical material on the main issues of the Gas Supply course, acquired skills in independent work in the field of gas supply systems design and experience in working with reference and special literature.

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