Gas supply of the city - high and low pressure networks

Contents

1. DETERMINATION OF LOWER COMBUSTION HEAT OF GASEOUS FUEL

2. DETERMINATION OF GAS CONSUMPTION BY THE AREA OF THE CITY

2.1 Determination of the number of inhabitants

2.2 Determination of estimated gas flow rates

2.3 Gas consumption for public utilities

2.4 Heat consumption for heating, ventilation and centralized hot water supply of residential and public buildings

2.5 Determination of estimated gas consumption by the city

3. HYDRAULIC CALCULATION OF LOW PRESSURE ANNULAR DISTRIBUTION GAS PIPELINES

3.1 Determination of the number of gas control stations (GRP)

3.2 Determination of gas travel expenses

3.3 LPC hydraulic calculation

3.4 Hydraulic linkage of LPC gas pipelines

4. HYDRAULIC CALCULATION OF HIGH OR MEDIUM PRESSURE MAIN GAS PIPELINES (HPG AND GSD)

4.1 Calculation of flow distribution at emergency operation mode of high or medium pressure network

5. SELECTION OF EQUIPMENT FOR GRP

5.1 Selection of pressure regulator

BIBLIOGRAPHIC LIST

Introduction

The purpose of the course design is to deepen and consolidate the knowledge gained during the study of the theoretical course "Gas Supply," mastering the design methodology, familiarization with the joint venture, SNiPamy and GOST. Get skills in routing and designing high (medium) pressure gas pipelines (HPG, GSD), low pressure distribution gas pipelines (LPG).

The project is carried out on a promising development plan for the city.

The general plan of the city indicates three residential areas:

No. 1 - promising multi-storey buildings (10 floors);

No. 2 - existing low-rise buildings (4 floors);

No. 3 - the existing area of ​ ​ a one-story manor building.

District No. 1.

Heating and hot water supply 100% of residential and public buildings are centralized from - from the CHP.

District No. 2.

Heating of all buildings, centralized from the CHP. Part of the residential buildings has decentralized hot water supply (HW) from flowing gas water heaters, part of the district buildings has centralized hot water supply from CHP and RTS.

District No. 3.

Decentralized heating from gas heating units or batch furnaces operating on gas. There is no hot water supply.

CHP burns gas for generation: 1) Electricity, 2) heat for needs:

• Heating and ventilation of residential and public buildings of districts No. 1 and No. 2;

• Hot water supply of districts No. 1 and No. 2;

• Heating and ventilation of industrial enterprises (PP) connected to the water heating network; PP heating and ventilation load within the specified process load is not more than 30%;

• Fabrikiprachnaya, which has a separate steam drive from the CHP;

• Baths located in residential areas and connected to the water heating network from the CHP.

Concentrated gas consumers having a high (medium) gas pressure at the inlet include:

• Bakeries;

• LPG of low pressure networks;

• PP (gas is used only for technological needs);

• District thermal stations (RTS);

• CHP (connected to the GRS by a separate gas pipeline, independent of the city gas network).

Hydraulic Calculation of Low Pressure Ring Gas Distribution Lines

The low-pressure network is designed to be cost-effective and to meet reliability requirements. It is implemented with condition of ring-shaped main gas pipelines, including those connecting power supply sources by low pressure.

The degree of ring and the principles of network design mainly depend on the type of planning and development of residential areas. The following conditions shall be observed:

- Ring;

- Two-way meals;

- Length of branches or dead ends from distribution network to consumers shall not exceed 300 m.

On the calculation scheme, gas flow distribution from the FRG to the confluence points is applied, section numbers are determined and the actual lengths of the gas pipeline sections are found according to the general plan. Design length of sections is determined taking into account gas pressure losses in local resistances (10% of linear losses).

3.1 Determination of the number of gas control stations (GRP)

Gas control stations are designed to reduce gas pressure and maintain it at a given level regardless of flow rate. For cities with a population of 50 to 250 thousand people, a two-stage gas supply system is recommended.

We accept 4 GRP.

After determining the number of GRP, we plan their location on the general plan of the city, installing them in the center of the gasified area, at the intersection of gas pipelines and in staggered order.,

Hydraulic Calculation of High or Medium Pressure Main Gas Lines (HP&G)

On the general plan of the district of the city, the laying of high or medium pressure gas pipelines is planned. 3looping of gas pipelines is most expedient in areas with multi-storey buildings of blocks. Gas pipelines are routed in such a way that the length of branches from the ring gas pipeline is minimal (not more than 200 m to increase the reliability of gas networks).

The high or medium pressure gas pipeline is joined by all industrial enterprises, baths, laundry, bakeries, district or quarterly boiler houses, CHP and gas regulatory centers (GRP).

Hydraulic calculation of main gas pipelines is carried out for two emergency and normal gas consumption modes.

The initial gas pressure is accepted according to the assignment (gas pressure at the outlet of the gas distribution station - GRS). The final gas pressure at the maximum load of the gas network shall ensure normal operation of the gas pressure regulator. In most cases, it is sufficient to have an excess gas pressure of about 150 kPa abs before the FRG.

ГАЗ.dwg