Reconstruction of the gas distribution station - course

Contents

CONTENTS

INTRODUCTION

GENERAL PART

Climatic conditions

Geological conditions

Object characteristic

PROCESS PART

Procedure of works execution

DESIGN PART

Calculation of pressure regulator selection

Calculation of safety valve selection

OCCUPATIONAL SAFETY

ENVIRONMENTAL PROTECTION

CONCLUSION

LIST OF SOURCES USED

INTRODUCTION

Russia's energy strategy defines the following main strategic goals for the development of the gas industry: stable, uninterrupted and cost-effective satisfaction of domestic and external gas demand; the development of the Unified Gas Supply System (ESG) and its expansion to the east of Russia, strengthening the integration of the regions of the country on this basis; improving the organizational structure of the gas industry. Currently, the share of gas in the energy resource of Russia is about 50%. An important element of the current gas transmission system is gas distribution systems. OAO Gazprom operates 3,764 gas distribution stations (GRS). The current state of GDS, as well as other facilities of main gas pipelines, is characterized by a number of negative trends: aging of fixed assets, low efficiency of equipment and gas pipelines, increased risk of failures, etc. In connection with the above, it becomes clear the significance of the reconstruction of the GRS.

In this course project, the object of the study is a gas distribution station in the city of Syktyvkar.

The subject of the study of the course project is the reconstruction of the GRS in the city of Syktyvkar.

The purpose of the project is to study the methods of reconstruction of the GDS.

To achieve the goal, we will set ourselves the following tasks:

1) Study the area and the object itself;

2) Perform calculations;

3) Study what types of work are carried out during the reconstruction of the RRS.

General part

Climatic conditions

The climate is temperate, summers are short and temperate cool, winters are snowy, long and moderately cold. The climate is formed in conditions of small amounts of solar radiation in winter, under the influence of the northern seas and the intense western transfer of air masses. The removal of warm sea air associated with the passage of Atlantic cyclones and the frequent incursions of Arctic air from the Arctic Ocean give the weather great instability throughout the year.

The annual amplitude is 32.3 ° C. The warmest month of the year is July (average monthly temperature + 16.7 ° C), the coldest month is January (15.6 ° C). The average annual air temperature according to the Syktyvkar weather station is 0.4 ° C. The number of days with an average daily air temperature above zero degrees is 187.

The territory belongs to the zone of humid climate with a very developed cyclonic activity. Especially heavy precipitation occurs with cyclones coming from the Black and Mediterranean Seas. Cyclones from the Atlantic bring precipitation less intense, but longer. The average annual rainfall in Syktyvkar is 560 mm.

Snow cover is a factor that has a significant impact on climate formation in winter, mainly due to the high reflectivity of the snow surface. At the same time, snow covers protect the soil from deep freezing. The most intense increase in snow cover height comes from November to January, in the months with the most repetitive cyclonic weather, when the main snow reserves remain. It reaches its greatest value in the second decade of March. The largest average height of snow cover in the winter according to snowmobile survey in the forest is 70 cm.

In general, winds of the south-west, southern direction prevail over the year. The average annual wind speed is 4.0 m/s.

Geological conditions

Relief. The district is located in the orographic region of the Vychegodsko Mezen plain. The relief is flat semi-wavy, dissected by developed river valleys. Watersheds have the form of flat elevations with a flat, gentle, less often hilly row surface.

The soils are typical strongly podzolic, peat podzolic gleate. On coastal terraces pr. Vychegdy and Sysola, mainly on a sandy substrate, glandular podzols are developed. In the valleys pr. Vychegdy and Sysola are common floodplain alluvial turf soils, usually occupied by meadows and shrubs.

Object characteristic

GRS is a complete prefabricated unit, tested and tuned for operating parameters. The overall dimensions of the GRS and the number of transport units depend on the operating parameters. The GRS can consist of several units that fit into the transport dimensions and are mounted at the place of operation in a single building or in a complex of structures. The GPC with a capacity of up to 30,000 nm3/h consists of one monoblock, which includes a technological room, a room of an autonomous boiler room combined with an electric panel, and an odorisation compartment, which are separated from each other by sealed partitions. Each room has a separate external entrance. The equipment of the process room provides gas preparation according to the required parameters. Boiler room equipment provides heating of rooms and gas heating. The electrical equipment provides uninterrupted power supply and automatic control of all RMS systems. Odorization equipment provides automatic odorization of gas with manual dubbing. The boiler house operates on gas, boilers for the commissioning period and in abnormal situations in winter can also work on solid fuel. The GRS is equipped with all necessary engineering systems (lighting, heating, ventilation, alarm) and emergency protection in accordance with the current design and operation codes and regulations. It also has 100% reserve of main process equipment. GCF can be supplied in any climatic design. The station operates in automatic mode without constant presence of maintenance personnel.

Process Part

The gas distribution station is designed to reduce the gas pressure level to the specified value, which is necessary in accordance with safe consumption standards. Its functions also include cleaning the medium from mechanical impurities and condensate, measuring and recording fuel consumption. The station is an important component in the modern gas transportation system and is a whole range of equipment, measuring and auxiliary devices.

The main consumers of the gas distribution station are:

- facilities of gas and oil fields;

- compressor stations;

- Small, medium and large settlements;

- power plants;

- industrial enterprises.

There are several GRS classifications. Consider the main ones:

Performance. Depending on this indicator, stations are small, medium and large. Their productivity is 1-50 thousand m3/h, respectively, 50-160 thousand m3/h. and over 160 thousand m3/h.

By appointment. GRS can be designed to be installed on a branch of the main gas pipeline, to prepare gas produced at the field, etc. There are also control and distribution points that are necessary for the supply of industrial and agricultural facilities, gas control points and gas control units. GRS on main gas pipelines can reduce pressure in a one-, two- or three-stage scheme.

By design. On this basis, stations are divided into three types: individual design, block-complete and automatic.

Let us dwell in more detail on the peculiarities of various GDS structures:

- individual design stations.

They are developed by specialized project organizations. Such stations are located near large settlements. They are characterized by improved equipment maintenance and management conditions.

- block-and-package RRS.

The use of stations of this design makes it possible to significantly reduce the time and cost of construction. The base of the GPC in this case is a block box, which is made of three-layer panels. It has high fire resistance and comparative lightness of construction. In addition, the box panels protect the equipment well from low temperatures (up to -45 ° C). The GPRS may have one or two output lines to consumers.

- automatic gas distribution stations (AGRS).

They consist of almost the same process units as the GRS of the previous two types. On the installation site, they are equipped with additional equipment and a fence. The main feature of these stations is automatic operation without the presence of people. These GRS reduce the pressure of natural, artificial or associated petroleum gas from high values (55 kgf/cm2) to low values (3-12 kgf/cm2).

Pressure regulators are divided according to the design of the throttling unit into one- and two-seat ones; according to the controlled output pressure - for regulating the conversion from high pressure (0.6 MPa and above) to high pressure (0.3-0.6 MPa), from high to medium (over 0.005 MPa), from high to low (up to 0.005 MPa), from medium (up to 0.3 MPa) to medium (over 0.005 MPa), from medium to low (up to 0.005 MPa); by the principle of action - on regulators of direct and indirect action. Direct action regulators use the energy of the working medium to move the plunger, i.e., the energy of the throttled gas flow. These regulators, in turn, are divided into two groups: 1) without a command node and 2) with a command node (pilot ).

In the regulators of the first group, the change in output pressure is perceived directly by the membrane drive of the regulator. The relatively simple design and high reliability of these regulators have led to their widespread use (regulators RD32M, RD50M, RD50/80/100 ).

Regulators of the second group are structurally more complex, since they have an additional control controller (pilot), which uses the energy of the working medium - the throttled gas flow. Input pressure gas is supplied to the pilot, which decreases in it and enters the membrane drive of the actuating unit, giving a signal for opening the throttling unit (RDC2).

Indirect regulators are those in which the plunger moves due to energy supplied from the outside (compressed air, water under pressure, electricity).

The GRS shall be equipped with a filter, safety shut-off valve (PSV), gas pressure regulator, safety discharge valve (PSV), shut-off valves, control measuring devices (instrumentation) and gas flow metering unit, if necessary, as well as a bypass gas pipeline (bypass) with two sequentially located disconnecting devices on it.

Filters shall have devices for determining the pressure drop in it, which characterizes the degree of clogging of the filter cartridge at the maximum gas flow rate. SZK and UCS shall ensure automatic cessation of gas supply or discharge to the atmosphere, respectively, when the pressure in the gas pipeline changes, which is unacceptable for safe and normal operation of gas-using and gas equipment. A purge and discharge piping system shall be provided to purge the gas lines and discharge the gas from the UCS, which shall be routed to the outside where safe conditions for gas dispersal are provided. GPU shall be equipped with or included in WG APCS showing and recording instruments for measuring gas inlet and outlet pressure, as well as gas temperature. Instrumentation with electrical output signal and electrical equipment with explosive zones shall be provided in explosion-proof design. The introduction of impulse gas lines into this room for the transmission of gas pressure pulses to the instruments should be carried out in such a way as to exclude the possibility of gas ingress into the instrument room. Electrical equipment and lighting shall comply with the requirements of electrical installation regulations.

Increasing or decreasing the gas pressure after the pressure regulator above the specified limits may lead to an emergency. With an excessive increase in gas pressure, flame may break off from the burners and the appearance of an explosive mixture in the working volume of gas-using equipment, leakage, gas leakage in the connections of gas pipelines and valves, failure of instrumentation, etc. A significant decrease in gas pressure can cause a flame to slip into the burner or a flame to go out, which, if the gas supply is not switched on, will cause the formation of an explosive gas-air mixture in the furnaces and gas ducts of the units and in the rooms of gasified buildings.

The reasons for the unacceptable increase or decrease in gas pressure after the pressure regulator for dead end networks are: - malfunction of the pressure regulator (jamming of the plunger, formation of hydrate plugs in the seat and body, leakage of the gate, etc.); - incorrect selection of the pressure regulator by its throughput, leading to two-position mode of its operation at low gas flow rates and causing surges in output pressure and self-oscillation. For ring and branched networks, the reasons for the unacceptable pressure change after the pressure regulator may be: - malfunction of one or more pressure regulators supplying these networks; - incorrect hydraulic calculation of the network, due to which jumping changes in gas consumption by large consumers lead to surges in output pressure. A common reason for a sharp pressure decrease for any networks may be a violation of the tightness of gas pipelines and valves, and therefore a gas leak. To prevent unacceptable pressure increase or decrease, high-speed safety shut-off valves (PSVs) and safety relief valves (PSVs) are installed.

BSVs are designed to automatically stop gas supply to consumers in case of pressure increase or decrease above the specified limits; they are installed after pressure regulators. BSVs are triggered in "emergency situations," therefore, their spontaneous activation is unacceptable. Before manual actuation of BSVK, it is necessary to detect and eliminate faults, as well as make sure that the shut-off devices are closed before all gas-using devices and units. If a break in gas supply is not allowed under the production conditions, then instead of BSVK there should be an alarm of maintenance personnel.

UCS are designed to release a certain excess volume of gas from the gas pipeline after the pressure regulator to the atmosphere in order to prevent pressure increase above the specified value; they are installed after pressure regulator on discharge pipeline. If there is a flow meter (gas counter), the UCS shall be installed after the meter. After the controlled pressure is reduced to the specified value, the UCS must close hermetically.

BSV is a valve open in operational condition. Gas flow through it is stopped as soon as at the controlled point of the gas pipeline the pressure reaches the lower or upper limit of the BSV setting.

The following requirements are made to the PZK:

- shall ensure tight closing of gas supply to the regulator in case of pressure increase or decrease beyond the specified limits. The upper limit of BSV actuation shall not exceed the maximum operating pressure after the regulator by more than 25%;

- calculated for the inlet operating pressure in a row: 0.05; 0,3; 0,6; 1,2; 1.6 MPa with the range of actuation at pressure increase from 0.002 to 0.75 MPa, as well as with the range of actuation at pressure decrease from 0.0003 to 0.03 MPa;

- the design shall exclude spontaneous opening of the shutoff element without intervention of maintenance personnel;

- tightness of the shutoff element must correspond to class "A" as per GOST 954493;

- accuracy of actuation shall be ± 5% of the specified values of controlled pressure for MPC installed on GPC and combined regulators;

- actuation inertia shall not exceed 4060 s;

- the free passage of the shutoff element shall be at least 80% of the conditional passage of the MPC branch pipes;

- the shut-off member must not be both an actuator of the gas pressure regulator.

PPV controlled pressure pulse shall be selected near the point of pressure regulator pulse extraction, i.e. at a distance from pressure regulator of at least five diameters of the outlet gas pipeline. At the same time, PZK is usually equipped with an electromagnetic device. The BSVs also include heat-intake valves that close the pipelines in case of temperature increase up to 8090 ° C.

2.1 Procedure of works execution

2.1.1 Replacement of gas equipment with new one is performed in the following order:

- cleaning of approaches to GRP from snow, ice, debris and foreign objects;

- external inspection checks the state of the territory around the GRP (BGRP, HRGP);

- through the hole in the door, the FRG room is checked for gas contamination by the instrument method;

- the door opens and the FRG room is ventilated;

- if necessary, transfer to bypass (standby reduction line);

- temporary supports are installed in the area of the disconnected gas pipeline (if necessary);

- removal of bolts on flange connections;

- threaded connections of pulse tubes are unscrewed and equipment to be replaced is removed;

- gaskets between flanges are removed;

- new equipment and new gaskets between flanges are installed, during installation of the gas pressure regulator it is necessary to ensure that both membrane chambers (regulator and pilot) are in horizontal position. Before installing the regulator on the reduction line, it is necessary to check its operability (in accordance with the current instruction of the gas equipment for a new one, it must be carried out according to the schedule approved by the technical head of the RRW, or according to the results of maintenance. Gas equipment to be installed shall be of the same type as replaceable in diameter and pressure;

- connect pulse tubes by tightening of threaded connections;

- bolts of flange connections are installed, tightened in staggered order and tightened if necessary;

- upon completion of gas equipment replacement, transfer from bypass (to working reduction line) is performed.

2.1.2 Instrument and UCS replacement shall be performed in the following order:

- if necessary, transfer to bypass (standby reduction line);

- threaded connection is twisted and control - measuring instrument or UCS to be replaced is removed;

- threaded connection is cleaned from old sealing material and lubricant;

- new sealing material and lubricant is applied to the threaded joint;

- clutches are twisted on the threads;

- if necessary, upon completion of gas equipment repair, transfer from bypass (to working reduction line);

- tightness of threaded joints with foaming solution or soap emulsion is checked;

- if necessary, threaded connections are tightened;

- upon completion of works the door is closed and the FRG room is checked for gas content.

Conclusion

In this course project, the gas distribution station was reconstructed with a complete replacement of equipment.

The purpose of the design is to increase the reliability of gas supply to consumers. In this regard, there is a complete replacement of obsolete and physically worn out AGRS equipment, which has been in operation since 1982. As well as an increase in the productivity of the GRS due to the increased need for gas and the installation of instruments for measuring the physicochemical characteristics of gas.

This GRS is designed in block-modular design. This arrangement allows solving the problems of reconstruction and overhaul of obsolete GRS with the placement of AGRS technological equipment both in blockboxes and in capital buildings.

The main GDS equipment is selected in accordance with the requirements of SNiP, GOST and the design assignment. According to the results of calculations, equipment was installed on the GRS.

RDU8001 regulators are installed as pressure regulators. AGDC allows automatic maintenance of the gas output pressure at a given level with an error of not more than 5%.

Газораспраспределительная станция _ 21.02.03.777.cdw