Drawings for automation for gas mains energy 1. Automation of the gas distribution station of the Sterlitamak linear production department of the main gas pipeline. Description of the technological scheme

Federal State Budgetary Educational Institution

higher professional education

"Ufa State Oil Technical University"

Department of Automation of Technological Processes and Production

Thesis project

Gas distribution station automation

Sterlitamak linear production department of the main gas pipeline

Student gr. AG 07-01 A.G. Askarova

Leader

Consultants:

cand. tech. Sciences, Assoc. S.V. Svetlakova

cand. tech. Sciences, Assoc. A.A. Gilyazov

Diploma project 109 p., 26 figures, 26 tables, 19 used sources, 1 annex.

GAS DISTRIBUTION STATION, EXCESS PRESSURE SENSOR, PRESSURE CONVERSION METHODS, "METRAN-100-VN-DI", ANALYSIS OF PRESSURE SENSORS

The object of the research is the automation of the gas distribution station of the Sterlitamak linear production department of the "Energy - 1" main gas pipeline.

In the course of the study, the analysis of the existing level of GDS automation was carried out, and the need to replace the gauge pressure sensors was justified.

The aim of the work is to modernize the automation system of the energy-1 gas distribution station.

As a result of the research, it was recommended to use an overpressure sensor “EJX430A” from “Yokogawa” for regulation and measurement at the gas distribution station. The algorithm of the logic control program for the transition of the gas distribution station to the bypass mode has been compiled.

Technical and economic characteristics confirm the feasibility of introducing a modern pressure sensor.

There is no implementation.

The effectiveness of the project lies in the high efficiency of the proposed replacement, since the devices being introduced are much better in terms of metrological characteristics.

Definitions, notation, abbreviations

Introduction

1.1 Purpose and composition of the GDS

1.4 Switching unit

1.5 Gas cleaning unit

1.6 Gas reduction unit

1.7 Gas heating unit

1.8 Gas odorization unit

1.9 Gas metering unit

2. Patent study

2.2 Search rules

2.3 Search results

2.4 Analysis of search results

3.1 Scope of automation

3.2 Information-measuring complex "Magistral-2

3.3 Pressure conversion methods

4. Modernization of the GDS automation system

4.1 Statement of the problem and analysis of the problem

4.2 Rationale for sensor selection

4.3 Sensor selection

4.4 Algorithm for the transition of the gas distribution station to the bypass mode

5. Occupational health and safety

5.1 Analysis of potential hazards and industrial hazards at GDS

5.2 Measures to ensure safe and harmless working conditions at the gas distribution station

5.3 Calculation of lightning protection of gas distribution stations

6. Assessment of the economic efficiency of modernization of the automation system of the GDS "Energia-1"

6.1 Criteria for assessing economic efficiency

6.2 Justification of the commercial effectiveness of the project

Conclusion

List of sources used

Definitions, symbols and abbreviations

GDS - gas distribution station

LPU - linear production management

MG - main gas pipeline

AWP - automated workstation

ACS - system automated control

РД - pressure regulators

BPG - gas heating unit

APCS - automated process control systems

Instrumentation - instrumentation

TCA - technical means of automation

SCADA - Supervisory Control And Data Acquisition

TR - strain gauge

KNS - "silicon on sapphire" technology

KNK - "silicon on silicon" technology

ADC - analog-to-digital converter

DAC - digital-to-analog converter

PAZ - emergency protection

NPV - net present value

ID - profitability index

IRR - Internal Rate of Return

CO - payback period

Introduction

GDS are designed to supply gas from main and field gas pipelines to settlements, enterprises and other large consumers. It is required to supply gas to the consumer in a given quantity and under a certain pressure, with the required degree of gas purification, heating and odorization (if necessary). The control system must be complex enough to accommodate the variety of static and dynamic characteristics of the plant.

With the help of automatic control of the gas distribution station, the highest productivity is ensured with the least expenditure of energy resources, cost reduction and product quality improvement, the number of maintenance personnel decreases, the reliability and durability of equipment increases, and working conditions and safety measures are improved.

The purpose of this diploma project is technical re-equipment, improvement of the existing automation system of the GDS "Energia-1", the introduction of modern automation equipment.

The objectives of the thesis project are:

Study of the technology of gas preparation for supply to the consumer;

Analysis of the automation system for GDS "Energy-1";

Modernization of the existing GDS automation system;

Drawing up an algorithm for the logic control program for the automatic transfer of the gas distribution station to the bypass mode.

During the work, materials from Sterlitamak LPU of GazpromtransgazUfa LLC were used.

1. Technological scheme of gas distribution station and its characteristics

1.1 Purpose and composition of the GDS

The basic technological process of the Sterlitamak LPU MGP of OOO GazpromtransgazUfa is the transportation of gas in the south of the Republic of Bashkortostan and its supply to the GDS, which supply gas to the consumer.

The station is a complex and responsible technological object of increased danger. Increased requirements are imposed on the technological equipment and means of automation of gas distribution stations for the reliability and safety of energy supply to consumers with gas, as well as for industrial safety, as for explosion and fire hazardous industrial facilities.

GDS are designed to supply gas from main and field gas pipelines to the following consumers:

Objects of gas and oil fields (for own needs);

Gas compressor station facilities;

Objects of small and medium-sized settlements;

Power plants;

Industrial, public utilities and settlements.

GDS provide:

Gas purification from mechanical impurities and condensate;

Gas heating;

Reduction of a given pressure and its constant maintenance with a certain accuracy;

Gas consumption measurement with multi-day registration;

Gas odorization is proportional to its consumption before supply to the consumer.

The GDS includes:

1) station switching;

2) gas cleaning;

3) prevention of hydrate formation;

4) gas reduction;

5) gas heating;

6) commercial measurement of gas consumption;

7) odorization of gas;

8) autonomous power supply;

Systems:

1) control and automation;

2) communications and telemechanics;

3) electric lighting, lightning protection, protection against static electricity;

4) electrochemical protection;

5) heating and ventilation;

6) burglar alarm;

7) control of gas pollution.

1.2 Description of the technological scheme

The technological scheme of the automated GDS "Energy-1" is shown in Figure 1.1.

The high-pressure gas supplied to the GDS inlet passes through the ball valve No. 1 to the PTPG-15M gas heater, where it is heated to prevent the precipitation of crystalline hydrates.

Heating is carried out in the coil by the radiation of the burner and the heat of the exhaust gases.

The heated high-pressure gas through taps No. 6,7 enters further into one of the reduction lines in the reduction block, combined with the purification unit, where the pressure is reduced to a given value and the process gas is purified from mechanical particles and liquid. The reduction unit consists of two reducing threads: working and reserve.

Figure 1.1 - Technological diagram of AGDS "Energia-1"

In the reduction unit, the fuel gas is reduced to power the burners from Pout to 0.1-0.2 Pa.

Low pressure gas flows from the reduction unit to the metering unit.

After the metering unit, the gas enters the odorization unit and then to the switching unit. Gas goes to the switching unit through the inlet valve No. 12 and is thrown out to the candle through the outlet line.

The prepared gas is supplied to the consumer with Pout \u003d 0.6 MPa.

1.3 Operating modes and operating parameters of the automated GDS "Energy-1"

GDS operate both autonomously and in the mode of constant presence of service personnel. In any case, the current state of the station is controlled by the LPU MG, on the territory of which the station is located.

For continuous monitoring and control (including automatic) of the state of all local GDS subsystems, it is necessary to have a local automated GDS control system connected with the dispatch control and management system of the entire GDS network from the MGP LPU.

On an automated gas distribution station, 3 control modes are possible:

Fully automatic;

Remote control of actuators from a remote operator workstation;

Remote manual and remote automatic control of actuators from the panel operator's workstation built into the ACS cabinet.

Automatic block GDS "Energia-1" are designed to supply individual consumers with natural, associated, oil, pre-purified from heavy hydrocarbons, and artificial gas from main gas pipelines with a pressure (1.2-7.5 MPa) by reducing the pressure to a given ( 0.3-1.2 MPa) and maintaining it. The Energia stations are operated in the open air in areas with a temperate climate at an ambient temperature of -40 ° C to +50 ° C with a relative humidity of 80% at 20 ° C.

The nominal throughput of the Energia-1 station is 10,000 m3 / h at an inlet pressure of Pin \u003d 7.5 MPa and Pout \u003d 0.3 MPa.

The maximum throughput of the station is 40,000 m3 / h of gas at an inlet pressure of Pvx \u003d 7.5 MPa and Pout \u003d 1.2 MPa. Table 1.1 shows the operating parameters of the automated gas distribution station "Energy-1".

Table 1.1 - Operating parameters of the automated gas distribution station "Energy-1"

Indicators	The values
Throughput, m3 / h
Working medium pressure, MPa: At the entrance At the exit	0,3; 0,6; 0,9; 1,2
Temperature, ° С: Environment In the premises of the GDS
Number of gas outlets
The minimum size of mechanical particles retained in filters, microns
Thermal power of the heater, kW
Gas consumption, m3 / h: For heater "PG-10" For heater "PTPG-30" For the heater "PGA-200"
Coolant pressure in the heater, MPa	Atmospheric
Heat carrier temperature, ° С
Odorizer type	Automatic with discrete feed
Overall dimensions L / W / H, mm Reduction unit Switch unit Odorization unit Instrumentation and control unit
Weight, kg Reduction unit Switch unit Odorization unit Instrumentation and control unit

1.4 Switching unit

The switching unit is designed to switch the gas flow from one line to another line of the gas pipeline, to ensure trouble-free and smooth operation GDS in cases of repair or carrying out hot and gas hazardous works. The bypass line connecting the gas pipelines of the GDS inlet and outlet is equipped with temperature and pressure measuring devices, as well as a shut-off valve and a regulator valve.

The switching unit is designed to protect the consumer gas pipeline system from possible high gas pressure. Also for supplying gas to the consumer, bypassing the gas distribution station, through the bypass line with the use of manual regulation of the gas pressure during repair and maintenance work of the station.

The GDS switching unit should provide for:

Cranes with pneumatic drive on gas pipelines inlet and outlet;

Safety valves with three-way switching valves on each outlet gas pipeline (it is allowed to replace, in the absence of a three-way valve, two manual valves with interlocking, excluding the simultaneous shutdown of the safety valves) and a gas discharge plug;

Isolating devices on the inlet and outlet gas pipelines to preserve the potential of cathodic protection with separate protection of the on-site communications of the gas distribution station and external gas pipelines;

A plug at the GDS inlet for emergency gas discharge from process pipelines;

A bypass line connecting the gas pipelines of the GDS inlet and outlet, providing a short-term gas supply to the consumer, bypassing the GDS.

GDS bypass line is designed for short-term gas supply for the period of revision, maintenance, replacement and repair of equipment. The bypass line must be equipped with two taps. The first is a shut-off valve, which is located along the gas flow and the second is a throttling valve-regulator. In the absence of a regulator valve, it is allowed to use a valve with a manual drive.

The switching unit consists of two valves (No. 1 on the inlet and No. 2 downstream gas pipelines), a bypass line and safety valves.

Through the safety valve, the gas (through the high-pressure inlet pipeline with a pressure of 5.4 MPa) enters the switching unit, which includes inlet and outlet pipelines with shut-off valves. Ball valves with a lever or pneumatic hydraulic actuator controlled locally by means of an electro-pneumatic control unit are used as shut-off valves. A spark plug valve is also provided for venting gas into the atmosphere.

Ball valves serve as a shut-off device on main gas pipelines, at gas collection and treatment points, at compressor stations, at gas distribution stations and can be operated in areas with a temperate and cold climate.

The valves are designed to operate at the following ambient temperatures:

In areas with a temperate climate from minus 45 to + 50 ° С;

In areas with a cold climate from minus 60 to + 40 ° С;

the relative humidity of the ambient air can be up to 98% at a temperature of plus 30 ° С.

The medium transported through the crane is natural gas, with a nominal pressure of up to 16.0 MPa and a temperature from minus 45 to + 80 ° C. The content of mechanical impurities in the gas is up to 10 mg / nm3, the particle size is up to 1 mm, moisture and condensate is up to 1200 mg / nm3. The use of valves to regulate the gas flow is prohibited.

In the absence of pressure or in the case when it is not enough to close the valve with a pneumatic hydraulic actuator, the shutdown is carried out by a manual hydraulic pump. The position of the pump handle of the spool switch must correspond to the marking: "O" - opening the valve by the pump, "3" - closing the pump or "D" - remote controlwhich is indicated on the pump cover.

The cranes ensure the passage of cleaning devices through them. The design of the valves provides the possibility of forced supply of sealing grease to the sealing area of \u200b\u200bthe ring seats and the spindle in case of loss of tightness. The system for supplying sealing grease to the ring seats of underground valves has double blocking by non-return valves: one valve in the fitting, and the second on the valve body in the boss. The fittings are of a single design, providing a quick connection for the adapter of the stuffing device.

Ring sealing valve seats ensure tightness at pressures from 0.1 to 1.1 MPa.

Pvx and Pout from the switching unit are monitored using pressure sensors. To protect low consumer networks, two spring-loaded safety valves are installed on the outlet pipeline, one of which is working, the other is backup. Valves of the "PPPK" \u200b\u200btype (spring-loaded full-lift safety valve) are used. During operation, the valves should be tested for operation once a month, and in winter - once every 10 days, with a record in the operating log. Valves of this type are equipped with a lever for forced opening and control purge of the gas pipeline. Depending on the setting pressure, the safety valves are equipped with replaceable springs.

For the possibility of revising and adjusting the spring safety valves without disconnecting consumers, a three-way valve of the KTS type is installed between the pipelines and the valves. Three-way valve type "KTS" is always open to one of the safety valves.

The setting of spring-loaded safety valves depends on the requirements of gas consumers, but generally this value does not exceed 12% of the nominal value of the outlet pressure.

Figure 1.2 shows a gas switching unit.

Figure 1.2 - Photo of the gas switching unit

In the switching unit there is a possibility to blow through the inlet and outlet pipelines through a spark plug valve, the pipeline of which is taken out of the GDS site.

The switching unit must be located at a distance of at least 10 m from buildings, structures or technological equipment installed in an open area.

1.5 Gas cleaning unit

The gas purification unit at the GDS allows to prevent the ingress of mechanical impurities and condensate into equipment, process pipelines, control and automation devices of the station and gas consumers.

For gas purification at the gas distribution station, dust-collecting devices of various designs are used, which provide gas preparation in accordance with the current regulatory documents for operation. The main requirement for the gas treatment unit is the automatic removal of condensate into collecting tanks, from there, as it accumulates, it is removed from the territory of the gas distribution station.

The gas purification unit should provide such a degree of gas purification when the concentration of impurity of solid particles with a size of 10 μm should not exceed 0.3 mg / kg, and the moisture content should not exceed values \u200b\u200bcorresponding to the state of gas saturation.

After the switching unit through the inlet taps, the gas enters the gas purification unit, which is combined with the reduction unit.

In the gas cleaning unit, mainly oil dust collectors, viscous filters and multi-cyclone separators are used. Oil dust collectors are used at stations with high hourly productivity.

An underground tank is installed at the GDS to collect and remove moisture and condensate with automatic control systems for the level and amount of condensate in tanks and dust collectors. The inlet and outlet pressure of each dust collector is monitored using pressure sensors.

For gas purification at the gas distribution station, dust-collecting devices must be used to ensure gas preparation for stable operation of the gas distribution station equipment and the consumer.

Filters 1 and 2, the location of which is presented in section 3, are designed to clean gas from mechanical impurities, as well as to drain condensate. For level signaling, sensors of the lower, upper and emergency level are installed in the filter accumulator. When assemblies with automatic sludge discharge are performed, the structure contains a pneumatically driven valve and a shut-off valve that is triggered at the boundary between liquid and gaseous fractions.

The gas purification unit includes filters-separators or a block of filter-separators designed to clean gas from solid particles and droplet moisture. The purification degree is 10 microns, the efficiency is 99.99%. Cleaning products from the storage tank of the filter-separators are automatically discharged into the condensate collection vessel.

The capacity of the tank should be determined from the condition of the impurities draining within 10 days

The tanks should be rated for the highest possible pressure and equipped with a liquid level switch.

In order to avoid emissions of condensate vapors and odorant into the atmosphere, it is necessary to take measures for their disposal.

The technological process of collecting gas cleaning products from reservoirs should exclude the possibility of spillage and ingress of liquid onto the ground.

Figure 1.3 shows a gas cleaning unit.

Figure 1.3 - Photo of a gas cleaning unit

1.6 Gas reduction unit

The reduction unit is designed to reduce the high inlet gas pressure Pvx \u003d 7.5 MPa to a low outlet pressure Pout \u003d 0.3 MPa and automatically maintain the set pressure at the outlet from the reduction unit, as well as to protect the consumer's gas pipeline from an unacceptable increase in pressure.

Since the reduction unit is combined with the purification unit, gas dehydration, removal of mechanical impurities and condensate drainage take place here.

The gas reduction unit at the gas distribution station performs one of the most important functions. Here, the high pressure gas is reduced to a predetermined value and automatically maintained at a predetermined level. The reduction unit consists of gas control equipment, shut-off valves, reduction lines, a protective automation system and an alarm system. In the schemes of the reduction unit, the following are used:

Steel control valves for a nominal pressure of 6.3 MPa;

Control valves of indirect action;

Direct acting taxiway.

To regulate pressure, direct-acting RD or regulators with analog control are used. Direct-acting regulators are faster and more reliable, since an intermediate link is excluded - communication channels and a control device, moreover, they do not require additional energy, since they work at the expense of the energy of the gas flow. Domestic manufacturers produce regulators that provide pressure regulation with an accuracy of 2.5%.

Control valves are more often used at gas distribution stations of large capacity, since they allow you to quickly change the regulated pressure at the valve outlet and have a large selection of standard sizes.

Proportional controllers of the RD type are used as command devices for indirect valves. There are two types of control valves: normally open (pressure is applied to the top of the diaphragm) and normally closed (below the diaphragm).

All control valves consist of a control element (valve) and a diaphragm actuator connected through a stem to the valve spool. The setting of the outlet gas pressure in all types of control valves is carried out by loading the valve stem with a spring.

The reduction unit is designed to lower the inlet pressure from 5.4 MPa to 0.6 MPa and supply gas through the low pressure pipeline to the linear networks of gas consumers.

In the GDS reduction unit, the number of reducing lines should be at least two (one reserve). It is allowed to use three reduction lines of equal performance (one standby).

In the reduction unit (Figure 1.4), if necessary, it is allowed to provide a line of low flow rates for operation in the initial period of operation of the GDS.

Figure 1.4 - Photo of the reduction unit

Reducing lines within one reduction unit must be equipped with the same type of shut-off and control valves. Gas reduction lines must be equipped with vent plugs.

Reducing lines must have automatic protection against deviations from operating parameters and automatic transfer switching.

1.7 Gas heating unit

A gas heating unit or BPG is designed for indirect heating of gas to a predetermined temperature, is used as part of a gas distribution station to exclude hydrate formation during gas reduction and maintain the gas temperature at the gas distribution station outlet at a given value, as well as to provide a coolant for space heating systems or other possible heat consumers.

BPGs are designed for operation in areas with a temperate and moderately cold climate, as well as in areas with a cold climate.

The standard size of the heating unit as part of the GDS should be determined from the conditions for ensuring the required gas temperature at the outlet of the GDS, the normal operation of the station equipment and the exclusion of its icing. In the case of using BPG in the heating circuit, it is necessary to take into account the additional heat load.

Gas is heated in a shell-and-tube heat exchanger by means of an intermediate heat carrier heated in a hot water boiler. The coolant, depending on the thermal power of the unit, is heated to 95 ° C and fed to the shell-and-tube heat exchanger, where heat is transferred to the heated body (gas), then the cooled coolant from the return heat pipe with a temperature of up to 95 ° C is fed to the inlet of the hot water boiler. In the presence of an additional heating circuit, the coolant is taken from the return heat pipe.

Structurally, the gas heating unit consists of a boiler block and a block of heat exchangers.

The equipment of these blocks is located in a box, hermetically divided into two compartments: a boiler room (category D) and a compartment for heat exchangers (category B-1a). The box is made of panels, has a removable roof, allowing quick installation and repair of heavy and large equipment. The block-box is resistant to seismic loads up to 9 points. The compactness of the unit and full factory readiness make it possible to carry out transportation, installation and commissioning in the shortest possible time.

The required heat output is provided by two hot water boilers in the boiler room compartment to increase the reliability of the unit. In the event of a failure of one boiler, the second can ensure the station's operation in emergency mode.

Circulation pumps are installed at the inlet of hot water boilers and operate under the control of the pump control and protection device in the operating time distribution mode. If one pump fails, a serviceable pump ensures 100% operability. To protect the system from exceeding the internal hydraulic pressure, boilers are equipped with safety relief devices (discharge is carried out into the expansion tank).

Power supply of the BPG is carried out from an industrial network 220 V / 50 Hz, or 380 V / 50 Hz. Power is supplied through an input cabinet equipped with residual current circuit breakers. An introductory cabinet is installed in the boiler room compartment.

1.8 Gas odorization unit

The condition for the safe operation of main gas pipelines, vessels, apparatus, equipment and instruments is the timely detection of gas leaks. The presence of gas in rooms can be detected using automatic instruments and systems. However, the simplest way to detect gas in air is to smell it. For this purpose, in our country and a number of other countries, gas is given a special unpleasant odor (odorized) by introducing ethyl mercaptan in an amount of 16 g per 1000 m3. The gas is odorized at the head facilities or at the field GDS.

Thus, after the metering unit, the gas enters the switching unit where it is odorized and then through the pipeline it goes to the low consumer networks.

To maintain a given degree of gas odorization, an odorant is introduced at the outlet of the gas distribution station using various devices. At the automated gas distribution station, a universal gas odorizer of the UOG-1 type is most often used. Below is table 1.4 with the technical characteristics of the UOG-1 gas odorizer.

Table 1.4 - Technical indicators of the "UOG-1" odorizer

The following requirements are imposed on odorants:

Odorants at the concentrations used for odorization must be physiologically harmless;

In a mixture with gas, odorants should not decompose, and also react with materials used on the gas pipeline;

The combustion products of odorants must be completely harmless and corrosive;

Odorant vapors should be slightly soluble in water or condensate;

Odorants must be volatile (to allow evaporation in a high pressure, low temperature stream).

Ethyl mercaptan (C2H5SH) satisfies these requirements to a large extent. The amount of odorant required to be introduced into the gas stream is determined by the threshold of its concentration at which a pungent odor is felt in the room. For natural gas, the signal rate is assumed to be 1% by volume. To maintain a given degree of gas odorization, the odorant is introduced into the stream using special devices called odorization units, which are divided according to the method of introducing the odorant into units with direct injection of a liquid odorant into the gas under pressure or by gravity and units for displacing odorant vapors with the gas flow. The first type includes drip odorizers, in which the odorant is introduced into the gas stream in the form of drops or a jet. The amount of injected odorant is manually adjusted with a needle valve. The odorizer operation is monitored through the sight glass.

Gas supplied to industrial enterprises and power plants, in agreement with the consumer, may not be odorized.

If there is a centralized gas odorization unit located on the main gas pipeline, it is allowed not to provide a gas odorization unit at the GDS.

Odorization unit is installed at the station outlet after the bypass line. Odorant delivery is allowed with both automatic and manual adjustment.

At the GDS, it is necessary to provide containers for storing the odorant. The volume of containers should be such that they are refueled no more than once every 2 months. Filling of containers and storage of the odorant, as well as gas odorization should be carried out in a closed way without releasing odorant vapors into the atmosphere or neutralizing them.

1.9 Gas metering unit

Gas metering unit is designed for commercial metering of gas (measuring its flow). The number of measurement lines depends mainly on the number of gas outlet pipelines from the gas distribution station.

After the reduction unit, the gas flows through the pipeline to the gas metering unit. Commercial metering of gas consumption for each consumer and gas metering for own needs is carried out at the gas metering unit. The unit provides gas flow rate measurement, flow rate correction for temperature, pressure and compressibility factor, gas quality analysis, and data logging.

The measurement of gas passing through the gas distribution station is based on the method of measuring the variable pressure drop. This method is characterized by the fact that when a restricting device is installed in a gas stream, the pressure drop across it depends on the amount of passing gas. The restriction device can be installed on the high or low side of the GDS.

The differential pressure is measured by a calculator, the type of which is selected simultaneously with the calculation of the orifice. The orifice device is connected to the calculator sensors by connecting lines.

Currently, the majority of the fleet of flow meters at gas metering units of OAO Gazprom is made up of measuring and computing systems that measure the flow rate by the pressure drop across the diaphragm. Some GDSs still use mechanical recorders. But, even in spite of the high accuracy of computer systems based on microprocessor technology (the error is not more than 0.5%), the total error of the flow meter unit due to the error of the diaphragm is at least 2.5%.

It is possible to reduce the flow measurement error by replacing the diaphragms with other types of flow sensors - turbine, rotary or vortex. Such complexes provide a total gas metering error of no more than 1.5-2.5% and do not require frequent replacement, like diaphragms.

When qualifying gas metering at a gas distribution station as commercial, it is required to determine not only the quantity, but also the quality of the gas being recorded in accordance with the requirements for self-supporting gas metering stations. Streaming analytical instruments allow you to obtain information about the quality of the gas with minimal discreteness.

The moisture and density of the gas are determined, respectively, by in-line moisture meters (dew point temperature meters) and density meters. The calorific value of the gas is measured with an on-line calorimeter. The use of flow chromatographs allows obtaining complete information on gas composition, calculating density and calorific value. Sulfur and hydrogen sulfide contents are determined by laboratory sulfur meters.

If it is necessary to regulate the gas flow rate at the outlet of the gas distribution station, flow controllers with analog control are used. To implement proportionally integral differential gas flow control, instead of correctors, so-called “flow computers” are used, which, in addition to regulating and correcting the gas flow, can receive information from the flow analytical equipment and transmit information in the form of reports to the control room.

2. Patent study

2.1 Selection and justification of the subject of the search

This thesis project examines the methods of converting pressure, the selection and implementation of a gauge pressure sensor.

One of the most important measured parameters at the GDS is pressure. At the moment, overpressure sensors Metran-100-Vn-DI have been installed at GDS "Energia-1"; the possibility of replacing this sensor with a modern overpressure sensor "EJX430A", the principle of which is based on the resonance method, is being considered. Therefore, during the patent search, special attention was paid to the search and analysis of gauge pressure sensors with a resonant pressure conversion method.

2.2 Search rules

The patent search was carried out using the funds of USPTU according to the sources of patent documentation Russian Federation and on foreign funds.

Search depth five years (2007-2011). The search was carried out on the indices of the International Patent Classification (IPC):

G01L 9/16 - Measurement of constant or slowly changing pressure of gaseous and liquid substances or bulk materials using electrical or magnetic elements sensitive to mechanical pressure by determining changes in the magnetic properties of bodies under load;

G01L 13/06 - Devices and instruments for measuring the difference of two or more values \u200b\u200bof fluid pressure using electrical or magnetic elements,

sensitive to mechanical pressure.

The following sources of patent information were used:

Full descriptions to patents of the Russian Federation;

Documents of the reference and retrieval apparatus;

Official Bulletin of the Russian Agency for Patents and Trademarks “Inventions. Utility Models "(2007-2011).

2.3 Search results

The results of the patent search are shown in Table 2.1.

Table 2.1 - Results of patent search

2.4 Analysis of search results

Consider the analogs shown in Table 2.1.

There are no analogues for patents G01L 9/16 and G01L 13/06.

The company "Yokogawa" (Japan) is the developer of DRHarp technology (resonant pressure transducer with a silicon resonator) and therefore there are no analogues in our country today.

3051S sensor patent: United States patent: 6082199. The new DPHarp sensor is based on the well-known "frequency-resonant" principle, which can be clearly demonstrated with the example of a string: the tension of the string is controlled by its own vibration frequency (tone). When the string is pulled, its tone (natural frequency) becomes higher, and when it is weakened, it becomes lower.

A silicon diaphragm is used as an elastic element, on which two sensitive elements are located. Sensitive elements - resonators are located so that their deformations differ in sign when a pressure difference is applied to the sensitive element.

The change in the natural frequency of the resonators is directly proportional to the applied pressure. Excitation of vibrations and transmission of the frequency of mechanical vibrations into an electrical frequency signal occurs by placing double-circuit resonators in a constant magnetic field and passing an alternating electric current through the resonator body in the excitation circuit.

Due to the effect of electromagnetic induction, an alternating EMF occurs in the measuring circuit with a frequency equal to the oscillation frequency of the resonator of the measuring circuit. The feedback of the excitation circuit along the measuring circuit, together with the effect of the shift of the frequency of forced vibrations towards the resonant frequency, ensures a constant correspondence of the frequency of electrical vibrations to the resonant (natural) frequency of mechanical vibrations of the resonator body. The natural frequency of such an unloaded resonator is usually about 90 kHz.

Today DPHarp sensing elements are the only serious alternative to capacitive and piezoresistive measurement methods. A large margin of accuracy and stability of the DPHarp sensing element has confirmed the feasibility of using the EJX430A differential pressure sensors.

3. Automation of GDS "Energy-1"

3.1 Scope of automation

3.1.1 Automation levels

As a rule, control and management systems are two-level systems, since it is at these levels that direct control of technological processes is implemented.

The lower level includes various sensors for collecting information about the course of the technological process, electric drives and actuators for the implementation of regulatory and control actions. Sensors provide information to local PLCs. As a rule, management tasks are solved at this level.

To reduce the human factor associated with the improper operation of complex technological equipment, it is necessary to introduce automation tools based on a human-machine interface, intuitive to humans, which should generalize, structure and systematize information.

The upper level includes, first of all, one or several control stations, which are the workstation of the dispatcher / operator. Basically, as workstations, PCs of various configurations are used.

The workstation of the GDS operator is necessary to improve the efficiency of the operator's (dispatcher's) interaction with the system and to reduce to zero his critical errors during control reducing the time for processing information, for finding the necessary information; improving the quality of control and accounting of analog and discrete parameters; control of technological equipment, i.e. increasing operator efficiency.

All components of the control system are interconnected by communication channels.

The interaction of the AWP with the ACS GDS is carried out via the Ethernet network.

The block diagram is shown in Fig. 3.1.

Figure 3.1 - Block diagram of the GDS control and management system

Functions performed by AWS ACS GRS:

Providing a user registration mechanism to protect against unauthorized control of GDS technological equipment;

Display on the monitor of mnemonic diagrams of the crane piping and technological equipment of the gas distribution station in the form of video frames made according to the principle of multilevel nesting from general to specific;

Visualization on the monitor of information from sensors and alarms about the state of the technological equipment of the gas distribution station, as well as information coming from local ACS in real time (gas heaters, etc.);

Display of analog parameters, including in the form of trends for

a given period of time, and control of their reliability;

Display of analog parameter settings with the possibility of changing them;

Displaying the states of executive mechanisms and monitoring their health;

Remote control of actuators (cranes, fans, discrete choke valve);

Registration and archiving of information with an agreed depth of retrospective about the state of the GDS crane piping, the state of the technological equipment, emergency and pre-emergency situations, the operator's actions (to control the technological equipment, change the settings of technological parameters);

Display and registration of gas consumption accounting for several metering units (instantaneous, daily, monthly consumption), changing configuration parameters, including taking into account the chemical composition of the gas;

Display of current alarm and warning information in the current alarm log;

Sound notification of the operator about an emergency, including emergency and warning sound signaling;

Automatic generation and printing of operator logs;

Maintaining archives of event logs, trends and operator logs.

The introduction of such systems at the GDS is of particular importance, since it allows to ensure the efficient operation of the GDS in the specified modes, improve the quality of work, ensure accident-free operation and environmental safety, and increase labor productivity.

GDS automation tools are designed to improve the reliable and stable operation of GDS and ensure continuous gas supply to consumers.

3.1.2 Automation functions

The complex of technical means of automation installed on the technological equipment provides:

Switching unit control, including:

1) measurement of gas pressure and temperature at the GDS inlet, comparison of measured values \u200b\u200bwith specified technological and emergency boundaries, generation and issuance of warning and alarm signals;

2) measuring the pressure and temperature of the gas at the outlet of the gas distribution station, comparing the measured values \u200b\u200bwith the specified technological and emergency boundaries, generating and issuing warning and alarm signals;

3) signaling the position of the switching unit valves, the GDS safety valve; remote (from the local control panel of the GDS and from the dispatching point) control of the cranes of the switching unit, the security valve of the GDS and automatic shutdown of the GDS in case of accidents. Gas purification unit control, including: pressure drop measurement in the separator;

4) signaling of the minimum and maximum permissible liquid level in the separator; remote and automatic control of the valve on the liquid discharge line depending on the liquid level in the filter-separator;

5) warning signaling of the maximum liquid level in the collection tanks;

Management of the hydrate prevention unit, including:

1) measurement of gas pressure and temperature at the outlet of the heating unit;

2) signaling the position of valves at the inlet and outlet of the heating unit, valve on the gas supply line bypassing the heater;

3) automatic and remote control of cranes;

4) signaling of heater operation from the heater control system;

5) heater alarm signaling;

Gas reduction unit control, including:

1) control of the position of the valves on the reduction lines;

2) automatic and remote switching on / off of reduction lines, including backup and auxiliary ones;

3) alarm of gas pressure on the reduction lines between sequentially installed regulating devices;

4) automatic regulation of the gas pressure supplied to consumers;

Commercial gas metering for each consumer, including:

1) measurement of parameters common to all consumers and the introduction of the necessary constants; gas pressure measurement; gas temperature measurement;

2) measurement of gas consumption (gas meter with pulse output);

3) calculation of gas consumption;

Gas odorization unit control, including:

1) signaling the minimum level in the odorant storage tank;

2) control of the dosed supply of the odorant to the gas;

3) signaling of the presence of odorant flow;

4) accounting for the amount of the introduced odorant;

Bypass crane control, including:

1) the position of the valve on the bypass line;

2) remote (from the local control panel of the GDS and from the control room) control of the crane on the bypass line;

Signaling the state of the power supply unit, including:

1) signaling of disconnection of the main power supply; signaling the state of the backup power supply;

2) signaling of switching to a backup source;

3) metering of electricity consumption;

Custody transfer gas metering for own needs, including metering:

1) parameters and the introduction of the necessary constants;

2) gas pressure;

3) gas temperature;

4) gas consumption (gas meter with pulse output);

Monitoring the state of the gas distribution station, including:

1) identification of emergency situations according to the appropriate algorithms, activation of emergency protection of the gas distribution station;

2) temperature measurement in the instrumentation unit;

3) signaling the presence of a pre-explosive concentration of natural gas in the premises of the GDS;

4) fire alarm;

5) signaling of penetration into the territory of the GDS and into the premises of the GDS;

6) signaling odorant leaks;

7) control of operation and control of the cathodic protection station (measurement of voltage, current, potential and regulation of the output voltage / current);

Self-diagnostics of the technical condition of ACS GDS, including:

1) troubleshooting of analog sensors with a unified output;

2) monitoring the integrity of the actuator circuits;

3) detection of failure, accurate to a typical input / output module;

4) identification of the lack of communication with the upper management level;

Presentation of information:

1) formation and delivery of information, including warning and emergency signaling, to the local control and management console, turning on the sound detector at the GDS;

2) formation and delivery of warning and alarm signals to the remote control, activation of the sound detector;

3) formation and delivery of information via communication channels to the control center;

4) processing, synchronization and execution of commands coming from the local console and from the control room;

5) remote (from the control room) disconnection of the GDS;

Secondary functions:

1) switching from the main power supply to the backup one without violating the operation algorithm and generating false signals;

2) protection against unauthorized access to information and management;

3) event logging.

3.1.3 PAZ system

The operational reliability of safety systems for hazardous industrial facilities depends entirely on the state of electronic and programmable electronic systemsrelated to security. These systems are called ESD systems. Such systems should be able to maintain their operability even in the event of failure of other functions of the GDS APCS.

Consider the main tasks assigned to such systems:

Prevention of accidents and minimization of the consequences of accidents;

Blocking (prevention) of intentional or unintentional interference with the technology of the object, which can lead to the development of a dangerous situation and initiate the ESD operation.

For some protections, a delay is provided between the detection of an alarm and the safety shutdown.

At the gas distribution station, a number of technological parameters are continuously monitored, the emergency values \u200b\u200bof which require shutdown and blocking of the operation of the gas distribution station facilities. Depending on the parameter or condition by which the protection was triggered, the following can be performed:

Automatic shutdown of the gas distribution station;

Closing the valves of the switching unit, the security valve;

Bypass crane control;

Switching to a backup source.

Test mode is provided for all protection parameters. In the test mode, the protection flag is set, an entry in the protection array and a message is sent to the operator, but control actions on the technological equipment are not generated.

Depending on which monitored parameter triggers the protection, the system must carry out:

Disconnection of GDS facilities;

Closing the valves;

Disconnection of certain auxiliary systems;

Turning on of light and sound alarm devices.

To ensure safe operation, gas pipelines are equipped with shut-off and control valves, safety devices, protection, automation, interlocks and measurements.

In front of the burners of gas-using installations, it is planned to install automatic high-speed shut-off valves with a class A shutter tightness in accordance with the state standard and a closing time of up to 1 s.

Power outage from external source causes the valve to close without additional energy supply from other external sources.

The design of shut-off, control valves, safety devices, electrical circuit protection devices, safety automatics, interlocks and measurements meets the requirements of regulatory and technical documentation agreed with the Gosgortekhnadzor of Russia. The design of shut-off, control valves and safety devices ensures the valve tightness of at least class B, resistance to the transported medium during the service life specified by the manufacturer.

The shut-off valves installed outdoors have an electric actuator in a design that corresponds to the outdoor temperature range specified in the technical data sheets for electric actuators, and must also be protected from atmospheric precipitation.

The design of gas pressure regulators should ensure:

Proportional band not exceeding ± 20% of the upper limit of the outlet pressure setting for regulators;

Deadband, not more than 2.5% of the upper limit of the outlet pressure setting;

A time constant (the time of the transient control process in case of sharp changes in the gas flow rate or inlet pressure), not exceeding 60 s.

Relative unregulated gas leakage through closed valves of double-seat regulators is allowed no more than 0.1% of the nominal flow; for a single-seat valve, the tightness of the closures must comply with class A according to the state standard.

The permissible unregulated gas leakage when used as regulating devices of butterfly valves should not exceed 1% of the capacity.

The accuracy of the operation of the safety shut-off valves should be ± 5% of the set values \u200b\u200bof the controlled pressure for safety valves installed on the GDS.

Safety relief valves shall be capable of opening when the specified maximum working pressure is exceeded by no more than 15%. The pressure at which the valve fully closes is set by the relevant standard or valve specification. Spring-loaded relief valves must be equipped with a device for their forced opening.

The permissible gas pressure drop across the filter is set by the manufacturer. Filters should have connections for connecting differential pressure gauges or other devices to determine the pressure drop across the filter.

The aggregate protection of the GDS must ensure its trouble-free operation and shutdown when the controlled parameters go beyond the established limits.

The algorithmic content of the ESD functions consists in the implementation of the following condition: when the values \u200b\u200bof certain technological parameters characterizing the state of the process or equipment go beyond the established (permissible) limits, the corresponding object or the entire plant must be shut down (stopped).

The input information for the ESD function group contains signals about the current values \u200b\u200bof the monitored technological parameters coming to the logic blocks (programmable controllers) from the corresponding primary measuring transducers, and digital data on the permissible limit values \u200b\u200bof these parameters, which are sent to the controllers from the operator's workstation. The output information of the ESD functions is represented by a set of control signals sent by the controllers to the executive bodies of the protection systems.

INTRODUCTION

In industry, along with the use of artificial gases, natural gas is increasingly being used. In our country, gas is supplied over long distances through large-diameter gas pipelines, which are a complex system of structures.

Gas from main gas pipelines enters city, settlement and industrial gas supply systems through gas distribution stations, which are the end sections of the main gas pipeline and are, as it were, the border between city and main gas pipelines.

Gas distribution station (GDS) is a set of installations and technical equipment, measuring and auxiliary systems for gas distribution and regulation of its pressure. Each GDS has its own purpose and functions. The main purpose of the GDS is to supply gas to consumers from main and field gas pipelines. The main gas consumers are:

Objects of gas and oil fields (own needs);

Compressor station facilities (own needs);

Objects of small, medium and large settlements, cities;

Power plants;

Industrial enterprises.

The gas distribution station performs a number of specific functions. First, it cleans the gas from mechanical impurities and condensate. Secondly, it reduces gas to a given pressure and maintains it with a given accuracy. Thirdly, it measures and registers gas consumption. Also, gas odorization is carried out at the gas distribution station before it is supplied to the consumer and gas is supplied to the consumer, bypassing the main blocks of the gas distribution station, in accordance with the requirement of GOST 5542-2014.

The station is a complex and responsible energy (technological) facility of increased danger. Increased requirements are imposed on the technological equipment of gas distribution stations in terms of reliability and safety of power supply to consumers with gas, industrial safety as an explosion and fire hazardous industrial facility.

1 Classification of gas distribution stations

Depending on the performance, design, number of outlet manifolds, gas distribution stations are conventionally divided into three large groups: small gas distribution station (1.0-50.0 thousand m3 / h), medium (50.0-160.0 thousand m3 / h) and high productivity (160.0-1000.0 thousand m3 / h or more).

Also, GDS are classified according to their structural characteristics (Figure 1). They are divided into the following types: individual design stations, block-complete GDS (BK-GDS) and automatic GDS (AGDS).

GDS

AGRS-1/3, AGRS-1, AGRS-3, AGRS-10

Energy-1M, Energy-2

Tashkent-1, Tashkent-2

Source

With two outputs

BK-GRS- II -70

BK-GRS-II -130

BK-GRS-II-160

With one outlet

BK-GRS- I -30

BK-GRS-I -80

BK-GRS I -150

Automatic

Individual design

Block-complete

Figure 1 - Classification of gas distribution stations

Custom design stations

GDS is designed by specialized design organizations in accordance with applicable rules, regulations technological design and sections of SNiP.

Individual design stations are those that are located near large settlements and in capital buildings. The advantage of these stations is the improvement of the conditions for servicing technological equipment and living conditions for the service personnel.

Block-complete GDS

BK-GRS allows you to greatly reduce costs and construction time. The main structure of the gas distribution station is a block-box made of three-layer prefabricated panels.

The largest mass of the block box is 12 tons. The degree of fire resistance is Sha. Design ambient temperature - 40 °C , for the northern version - 45 °C ... Delivery of all elements of the modular-complete gas distribution station is carried out by the manufacturer. At the installation site, the blocks are connected by gas pipelines and cables, equipped with auxiliary equipment (lightning rod, purge plug, searchlights, burglar alarms, etc.) and a fence, forming a complete complex.

BK-GRS are intended for gas supply of cities, settlements and industrial enterprises from main gas pipelines with a gas pressure of 12-55 kgf / cm2 and maintaining the outlet pressure of 3, 6, 12 kgf / cm2 .

Block-complete GDS can be with one or two output lines to consumers (Figures 2 and 3). There are known BK-GRS of six standard sizes. With one outlet to the consumer, three standard sizes - BK-GRS-I -30, BK-GRS-I-80, BK-GRS-I -150. And also three standard sizes with two outputs to the consumer - BK-GRS-II -70, BK-GRS-II -130 and BK-GRS-II -160.

Figure 2 - Block diagram of a gas distribution station with one consumer

Figure 3 - Block diagram of a gas distribution station with two consumers

BK-GRS of all standard sizes are used in Russia and the CIS countries, but they are all undergoing reconstruction at the installation site according to individual projects, since they have significant design flaws in the units for purification, heating, reduction and gas metering.

Automatic GDS

Automatic GDS contains basically the same technological units as GDS of individual or block-complete type. At the assembly site, they are also equipped with auxiliary equipment and a fence, like the BK-GRS. AGDS, unlike other types of gas distribution stations, operate using unmanned technology.

These stations are designed to reduce high pressure (55 kgf / cm2 ) natural, associated oil, artificial gases, not containing aggressive impurities, to a predetermined low (3-12 kgf / cm2 ), maintaining it with a given accuracy of ± 10%, as well as for preparing gas before supplying to the consumer in accordance with the requirements of GOST 5542-2014.

All AGDS are designed for outdoor operation in areas with seismicity up to 7 points on the Richter scale, with a temperate climate, at an ambient temperature from minus 40 to 50 °C with relative humidity of 95% at 35 ° C.

During the operation of the AGDS, significant design flaws are revealed, which for the most part boil down to the following:

Failure of gas pressure regulators due to condensate falling out in the process of gas reduction in the form of ice flakes and sticking of the regulator valve;

Failure of instrumentation devices in winter due to low temperatures in instrumentation and alarm units heated by lighting lamps.

Technological schemes and principle of operation of gas distribution stations of different types

2.1 Flow diagram and principle of operation of individual design gas distribution stations

There are various GDS technological schemes. Let's consider the technological scheme using the example of GDS-5 (Figure 4).

Gas from the main gas pipeline GM1 is supplied under pressure through the PI1 insulating flange, the KV inlet valve to the UR1 first stage reduction unit. The reduction unit contains input CL1 and output CL2 collectors. Gas from the outlet manifold enters the working line, which consists of three parallel-connected lines L1-L3 with shut-off valves K1-K3 and valves K4-K6. With the help of K4-K6 valves, manual gas reduction is carried out under a pressure of 3 MPa. There is also a bypass line with a K7 valve. In the reduction unit, a reserve line is provided, which has the same equipment as the working line: lines L4-L6, stopcocks K8-K10, gate valves K11-K13 and bypass valve K14. In the outlet manifold, the main K17 and the reserve K18 three-way cocks with safety valves KP1-KP4 are installed, which protect the manifold from excessive pressure increase.

From the outlet manifold of the first stage of reduction, gas is directed through an odorization unit with a working tank E1, an insulating flange FI2 into the main gas pipeline GM2 and into the second stage reduction unit UR2. Through the main gas pipeline GM2, gas can be supplied to a large consumer, for example, a gas processing plant, or vice versa, gas can be obtained from this plant and supplied to the second stage reduction unit.

The gas enters the second stage reduction unit through the UPR switching unit containing the K61-K65 valves, the K66 three-way valve with the KP5, KP6 safety valves and the UO purification unit, consisting of inlet KL3, outlet KL4 collectors, inlet K19, K21, K23, K25, K27 valves with K29-K33 bypass valves of smaller nominal diameter, outlet valves K20, K22, K24, K26, K28, gas separators GS1-GS5 with mesh nozzles. There is also a K34 bypass valve for the cleaning unit. Inlet KL5 and outlet KL6 collectors of the reduction unit are connected by reduction lines L7-L14, equipped with inlet stopcocks K35-K42, regulators RD1RD8, outlet stopcocks K43-K50. To reduce and maintain a constant gas pressure at the outlet, devices such as RDU and LORD-150 are used as regulators RD1-RD8.

After leaving the reduction unit, the gas enters the input manifold KL7 of the metering unit of the UU, which is connected to the outlet manifold KL8 by gas flow measurement lines L15-L19.

Figure 4 - Technological scheme of the GRS-5. Individual project.

These lines are equipped with measuring diaphragms D1-D5, as well as inlet K51-K55 and outlet K56-K60 shut-off valves. From the outlet manifold KL8, gas, passing through the taps K62, K64 of the switching unit, odorization unit UO2 with working capacity E2 and insulating flange FI3, enters the gas distribution pipeline GR. The working tanks of odorization plants are periodically replenished from the underground storage tank E3 of the odorant.

2.2 Technological scheme and principle of operation of BK_GRS

As an example, let us consider the technological scheme of a block-complete GDS brand BK-GRS-I -30 (Figure 5).

GDS works as follows. High pressure gas enters the BPR switching unit, consisting of taps K1, K2, on the inlet and outlet gas pipelines, bypass line L1 with valves K3, K4, three-way valve K5, safety valves KP1, KP2, and discharge line L2 to the spark plug with valve K6 from the high pressure line. From the BPR block, gas is directed to the BOC cleaning unit, which consists of two multi-cyclone dust collectors МЦП1, МЦП2, shut-off valves К7-К10, bypass line L3 with valve К11. Valves K7-K11 allow shutting off one or two multicyclones for cleaning and repair work, while passing gas through one of the multicyclones or bypass line L3. Multicyclones are designed to clean gas from mechanical impurities and condensate. Drainage of condensate from dust collectors is automated using level regulators and diaphragm-operated valves.

The cleaned gas enters the BPD heating unit. Gas heating is carried out by a fire heater of the PGA-10 type.

From the heating unit, the gas enters the BR reduction unit, which consists of two lines L4, L5: working and reserve. Both lines have the same equipment and their functions change periodically. On the reduction lines, there are K12, K13 valves with a pneumatic drive, gas pressure regulators RD1 and RD2 of the RD-100-64 type and K14, K15 valves with a manual drive at the outlet. In case of failure of the working line, the "Protection-2" system is triggered when the gas pressure rises at the outlet of the reduction unit, with which it is connected with the help of the impulse line L6, which can be shut off by the valve K16.

From the BR reduction unit, gas enters the gas metering unit (flow measurement), consisting of two lines L7, L8: working and reserve. The gas flow rate is measured by chamber diaphragms D1 and D2 of the DK-100 type and recorded by differential pressure gauges-flow meters DR. Cranes K17-K20 allow switching between the working and backup lines L7, L8.

Figure 5 - Technological scheme of GDS brand BK-GRS-I -30

After the metering unit, gas passes through the switching unit and enters the BOD odorization unit, where a universal odorizer of the UOG-1 type is installed. The block contains a consumable РС1, underground РС2 tanks, a U level gauge, a CO viewing window and valves for controlling the block operation.

After exiting the odorization unit, the gas enters the network to consumers.

Insulating flanges FI1, FI2 are installed on the inlet and outlet gas pipelines of all standard sizes BK-GDS, preventing the penetration of stray currents into the station equipment.

The emergency warning system provides an undeciphered signal to the DO and the dispatcher's console in the event of a station malfunction.

2.3 Technological scheme and principle of operation of AGDS

As an example, let us consider the technological scheme of an automatic gas distribution station of the AGRS-10 brand (Figure 6).

AGDS-10 operates according to the following scheme. The high-pressure gas enters the switching unit, which consists of gas lines, a bypass line with two valves, a safety valve assembly with a three-way valve, manually operated plug valves and pressure gauges. When gas is supplied to the consumer through the bypass line, gas reduction is carried out manually using a valve.

From the switching unit, the gas is directed to the PG-10 fired gas heater. The heated gas enters the purification unit, where it is cleaned from mechanical impurities with the help of filters, and then is sent to the reduction unit. All units of the reduction unit, as well as the heating unit, are located in a metal cabinet with three double doors, which provide free access to all units and controls.

The reduction unit contains two reducing lines (working and reserve) with a pressure regulator of the RDU-50 type, cork cranes with both manual and pneumatic drives, a multiplier and control units for them, a relief valve, a board with electrical contact pressure gauges, an automation and protection board , filter driers for command gas. From the reduction unit, gas enters the gas metering unit with chamber diaphragms of the DK-200 type, the gas flow rate is recorded with differential pressure meters. Then the gas enters the odorization unit, where the UOG-1 type odorizer is installed.

AGDS is equipped with a remote alarm system to monitor the operation of the main units of the station. The control over the mode of the units is carried out by sensors connected by cable lines with the transmitting unit of remote alarm signaling installed in the instrumentation unit.

1 - manual input valve; 2 - gas heater; 3 - a crane with a pneumatic drive; 4 - filter; 5 - gas pressure regulator; 6.12 - cranes with manual drive; 7 - metering unit; 8 - gas odorizer; 9 - container for odorant; 10 - safety valve; 11 - three-way valve; 13 - cabinet gas control unit; 14 - insulating flange; 15 - bypass line.

Figure 6 - Technological scheme of the gas distribution station of the AGRS-10 brand

Typical equipment at GDS

The gas distribution station includes:

Nodes:

a) station switching;

b) gas cleaning;

c) prevention of hydrate formation;

d) gas reduction;

e) gas heating;

f) commercial measurement of gas consumption;

g) odorization of gas (if necessary);

h) autonomous power supply;

i) gas selection for own needs;

Systems:

a) control and automation;

b) communications and telemechanics;

c) electric lighting, lightning protection, protection against static electricity;

d) electrochemical protection;

e) heating and ventilation;

f) security alarm;

g) control of gas pollution.

The GDS switching unit is designed to switch the high-pressure gas flow from automatic to manual pressure regulation along the bypass line, as well as to prevent an increase in pressure in the gas supply line using safety valves.

Gas purification unit GDS is designed to prevent the ingress of mechanical (solid and liquid) impurities into technological and gas control equipment and control and automation equipment.

The hydrate prevention unit is designed to prevent the reinforcement from freezing and the formation of crystalline hydrates in gas pipelines and valves.

The gas reduction unit is designed to reduce and automatically maintain the set pressure of the supplied gas.

Gas metering unit is intended for metering the amount of gas consumption using various flow meters and counters.

The gas odorization unit is intended for adding substances with a strong unpleasant odor (odorants) to the gas. This allows early detection of gas leaks by smell without special equipment.

These units and systems consist of equipment that performs the functions intended for the elements that make up the GDS.

Industrial fittings

Industrial fittings - a device installed on pipelines, units, vessels and designed to control (shutdown, regulation, discharge, distribution, mixing, phase distribution) flows of working media (gaseous, liquid, gas-liquid, powder, suspension, etc.) by changing flow area.

There are a number state standardsregulating the requirements for valves. In particular, the main parameters of the cranes must be observed in accordance with GOST 21345-2005.

Industrial valves are characterized by two main parameters: nominal bore (nominal size) and nominal (nominal) pressure. Under the conditional passageDN or D y understand the parameter used for pipeline systems as a characteristic of the connected parts (GOST 28338-89). Nominal pressurePN or P y - the highest overpressure at a working medium temperature of 20 °C , at which the specified service life of the fittings and pipeline connections, having certain dimensions, justified by strength calculations for the selected materials and characteristics, their strength at a temperature of 20 ° C is provided. Values \u200b\u200band designations of nominal pressures must correspond to those specified in GOST 26349-84.

Industrial fittings can be classified according to several criteria.

Functional purpose (type).

Locking. Designed to completely shut off (or completely open) the flow of the working medium, depending on the requirements of the technological regime.

Regulating (reduction). Designed to regulate the parameters of the working environment by changing its flow rate. It includes: pressure regulators (Figure 7), control valves, liquid level regulators, throttling valves, etc.

Safety. Designed for automatic protection of equipment and pipelines from unacceptable pressure by dumping excess working medium. These include: safety valves, impulse relief devices, diaphragm burst devices, by-pass valves.

Protective. Designed for automatic protection of equipment and pipelines from inadmissible or not provided by the technological process changes in parameters or direction of the flow of the working medium and to shut off the flow without dumping the working medium from the technological system. This includes check valves and shut-off valves.

Phase separation. Designed for automatic separation of working media depending on their phase and state. These include condensate traps, oil separators, gas separators, air separators.

Figure 7 - The device of the pressure regulator

Constructive types.

Gate valves. Their working body moves reciprocally perpendicular to the flow of the working medium. It is mainly used as a shut-off valve.

Valves (valves) (Figure 8). Their shut-off or regulating working body moves reciprocally parallel to the axis of the working medium flow.

Cranes. Their shut-off or regulating working body has the shape of a body of revolution or part of it, rotates around its axis, arbitrarily located in relation to the flow of the working medium.

Closures. Their shut-off or regulating body, as a rule, has the shape of a disk and rotates around an axis that is not its own.

Figure 8 - Three-way valve (valve)

Gas pressure regulators

The hydraulic operating mode of the gas distribution system is controlled using pressure regulators. A gas pressure regulator (RD) (Figure 9) is a device for lowering (reducing) the gas pressure and maintaining the outlet pressure within specified limits regardless of changes in inlet pressure and gas flow rate, which is achieved by automatically changing the degree of opening of the regulator of the regulator, as a result of which also the hydraulic resistance to the passing gas flow changes automatically.

RD is a combination of the following components:

A sensor that continuously monitors the current value of the controlled variable and sends a signal to the control device;

A regulator that generates a signal of the set value of the controlled variable (required output pressure) and also transmits it to the regulating device;

A regulating device that carries out the algebraic summation of the current and set values \u200b\u200bof the controlled variable, and the command signal gets to the executive mechanism;

An actuator that converts the command signal into a control action, and into the corresponding movement of the control body due to the energy of the working environment.

1 - control valve; 2 - direct-acting control regulator; 3.4 - adjustable choke; 5 - throttle.

Figure 9 - Gas pressure regulator RDBK1P

Due to the fact that the gas pressure regulator is designed to maintain constant pressure at a given point of the gas network, it is always necessary to consider the automatic control system as a whole - “the regulator and the object of regulation (gas network)”.

The correct selection of the pressure regulator must ensure the stability of the "regulator - gas network" system, i.e. its ability to return to its original state after the end of the indignation.

Depending on the pressure maintained (the location of the controlled point in the gas pipeline), the taxiway is divided into “upstream” and “downstream” regulators.

Proceeding from the regulation law underlying the operation, pressure regulators are astatic (working out the integral regulation law), static (working out the proportional regulation law) and isodromic (working out the proportional-integral regulation law).

In statistical taxiways, the amount of change in the control orifice is directly proportional to the change in gas flow in the network and is inversely proportional to the change in outlet pressure. An example of a static pressure regulator is a spring-loaded downstream pressure regulator.

RD with an integral regulation law in the event of a change in the gas flow rate creates an oscillatory mode due to the regulation process itself. As the gas flow rate changes, the difference between the original and target outlet pressure values \u200b\u200bincreases until the amount of gas passing through the regulator is less than the new flow rate and reaches its maximum when these values \u200b\u200bare compared. At this moment, the opening speed of the control hole is maximum. But the regulator does not stop there, but continues to open the hole, letting in more gas than is required, and the outlet pressure, accordingly, also increases. The result is a series of fluctuations around a certain average value, at which a constant mode (as in the case of a static controller) will never be reached.

Representatives of astatic regulators are RD with a pneumatic output pressure regulator, and a typical example of such a process can be considered continuous self-oscillations of some types of pilot taxiways in certain transient operating modes.

The isodromic regulator (with elastic feedback), when the controlled pressure deviates, will first move the regulated element by an amount proportional to the deviation, but if the pressure does not come to the set value, the regulator will move until the pressure reaches the set value. Such a regulator combines integral precision and proportional speed. Representatives of isodromic taxiways are "once-through" regulators[ 9 ] .

Gas filters

Gas filters are designed to clean gas from dust, rust, tarry substances and other solid particles. High-quality gas purification increases the tightness of locking devices and increases the time between repairs of these devices by reducing the wear of the sealing surfaces. This reduces wear and increases the accuracy of flow meters (meters and orifice plates), which are especially sensitive to erosion. The correct choice of filters and their qualified operation are one of the most important measures to ensure the reliable and safe functioning of the gas supply system.

In the direction of gas movement through the filter element, all filters can be divided into direct-flow and rotary, according to their design - into linear and angular, according to the material of the body and the method of its manufacture - into cast iron (or aluminum) cast and steel welded.

When designing and choosing filters, the filter material is especially important, which must be chemically insensitive to gas, provide the required degree of purification and not be destroyed under the influence of the working environment and during periodic filter cleaning.

According to the filter material chosen for the filter, they are divided into mesh (Figure 10) and hair (Figure 11). In mesh, a braided metal mesh is used, and in hair, cassettes filled with nylon thread (or pressed horsehair) and impregnated with viscinic oil.

1 - case; 2 - cassette; 3 - mesh; 5 - cover.

Figure 10 - Mesh filter type FS

1 - case; 2 - striker plate; 3 - cassette; 4 - perforated sheet; 5 - filter element; 6 - cover; 7 - fittings; 8 - flange.

Figure 11 - FG hair filter

Mesh filters, especially two-layer filters, are distinguished by their increased fineness and cleaning intensity. During operation, as the mesh becomes clogged, the filtration fineness increases while the filter throughput decreases. In the case of hair filters, on the contrary, during operation, the filtering ability decreases due to the entrainment of particles of the filtering material by the gas flow and with periodic cleaning by shaking.

To ensure a sufficient degree of gas purification without entrainment of solid particles and filtering material, the gas flow rate is limited and characterized by the maximum allowable pressure drop across the mesh or filter cartridge.

For mesh filters, the maximum allowable pressure drop should not exceed 5000 Pa, for hair filters - 10000 Pa. In the filter before the start of operation or after cleaning and rinsing, this difference should be 2000–2500 Pa for mesh filters, and 4000–5000 Pa for hair filters. The design of the filters has fittings for connecting devices, with the help of which the value of the pressure drop across the filter element is determined.

Safety valves

An increase or decrease in gas pressure after the pressure regulator beyond the specified limits can lead to an emergency. With an excessive increase in gas pressure, the flame may burst at 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 fittings, failure of instrumentation, etc. A significant decrease in gas pressure can lead to flame breakthrough into the burner or flame out, which, if the gas supply is not turned off, 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.

A common reason for a sharp drop in pressure for any network can be a leakage of gas pipelines and fittings, and, consequently, a gas leak.

To prevent an unacceptable increase or decrease in pressure, fast-acting safety shut-off valves (SSV) (Figure 12) and safety relief valves (Figure 13) (PSK) are installed.

Shut-off valves are designed to automatically cut off gas supply to consumers in case of pressure increase or decrease in excess of preset limits; they are installed after pressure regulators. The slam-shut valves are triggered in "emergency situations", therefore, their spontaneous activation is unacceptable. Before manually turning on the slam-shut device, it is necessary to detect and eliminate malfunctions, and also make sure that the locking devices are closed in front of all gas-using devices and units. If, according to the production conditions, an interruption in the gas supply is unacceptable, then instead of the shut-off device, a warning signaling for the operating personnel should be provided.

Building - 1; Adapter flange - 2; Cover - 3; Membrane - 4; Large spring - 5; Cork - 6; Small spring - 7; Stem - 8; Valve - 9; Guide post - 10; Plate - 11; Fork - 12; Rotary shaft - 13; Lever - 14; Anchor lever - 15; Rocker - 16; Hammer - 17.

Figure 12 - Safety shut-off valve

PSK are designed to discharge into the atmosphere a certain excess volume of gas from the gas pipeline after the pressure regulator in order to prevent pressure increase above the set value; they are installed after the pressure regulator on the outlet pipeline.

1 - case; 2 - cover; 3 - valve with a guide; 4 - spring; 5 - adjusting screw; 6 - membrane; 7 - plate; 8 - spring plate; 9 - cover.

Figure 13 - Safety relief valve

If there is a flow meter (gas meter), the PSK must be installed after the meter. After the controlled pressure has dropped to the set value, the PSC must close hermetically.

Gas consumption meters

The highest accuracy metering devices should be installed at the GDS.

If the volume of gas transportation exceeds 200 million cubic meters3 per year, in order to increase the reliability and reliability of gas volume measurements, it is recommended to use duplicate measuring instruments (SI). Duplicate SI should not affect the operation of the main SI. It is recommended that the primary and secondary metering systems use different methods for measuring gas flow and quantity.

At measuring nodes with a maximum gas volumetric flow rate of more than 100 m3 / h, at any gauge pressure or volumetric flow range from 16 m3 / h up to 100 m 3 / h, at an excess pressure of more than 0.005 MPa, the gas volume is measured only using calculators or gas volume correctors.

With an overpressure of no more than 0.005 MPa and a volumetric flow of no more than 100 m3 / h it is allowed to use flow converters with automatic correction of the gas volume only by its temperature.

The composition of measuring instruments and auxiliary devices on the basis of which the gas metering unit is made is determined:

The applied measurement method and the requirements of the measurement procedure governing the measurement;

Purpose of metering unit;

The given gas flow rate and the range of its change;

Gas pressure and quality indicators, taking into account gas sampling modes;

The need to include metering stations in automated gas commercial metering systems.

In general, gas metering includes:

Flow transducer for measuring gas volume and flow;

Measuring pipelines;

Gas quality treatment facilities;

Gas quality analyzers;

A set of technical means of automation, including processing, storage and transmission of information.

3.6 Gas odorizers

The gas odorizer is designed for dosed supply of an odorant (a mixture of natural mercaptans) into the gas flow at the outlet line of a gas distribution station with a working pressure of up to 1.2 MPa (12 kgf / cm2), in order to impart a characteristic odor to the gas.

The gas odorizer is used as part of the gas distribution station and provides:

Dosed supply of the odorant into the pipeline;

Control of the injected dose of the odorant and automatic correction of the odorant flow rate depending on the current gas flow rate;

Automatic accounting of the total consumption of the odorant;

Display of the following information on the display screen of the odorizer control unit (CUO):

a) odorant level in the working container;

b) the current value of the hourly gas consumption received from the flow meter;

c) odorizer operating time;

d) the accumulated total value of the odorant consumption since the start of the ODDK;

e) emergency and warning signals.

Communication with various upper-level systems using an agreed protocol.

Odorizers are designed for outdoor operation in areas with seismicity up to 9 points with moderate and cold climates in conditions standardized for UHL performance, location category 1 in accordance with GOST 15150-69. The location of the odorizer control unit is determined by the project for linking the ODDK or GDS in the explosion-proof zone, in a heated room.

3.7 Gas heaters

Gas heaters are designed to heat up and automatically maintain the set gas temperature before throttling it at gas distribution stations. Gas is heated to ensure the reliability of the process equipment. Working medium: gaseous media that do not contain aggressive impurities.

Thermal power produced Russian enterprises heaters exceeds the actual needs of the gas distribution station. As a result, 75% of heaters operate at less than 50% load, 51% with less than 30% load, 15% with less than 10% load. Of more than 150 modifications of direct heating gas heaters and with an intermediate coolant produced by the domestic industry, the direct heating gas heaters PGA-5, PGA-10, PGA-100 satisfy in terms of thermal power.

PGA heaters with an intermediate coolant are designed to heat natural, associated and oil gas to a predetermined temperature and can be operated both as part of gas distribution stations and independently. As a rule, PHA heaters are equipped with a modern automation system designed for autonomous and remote control.

The main advantage of PHA heaters is that the gas is heated through an intermediate heat carrier, which can be used as diethylene glycol or a cooling liquid. Due to this, PHA heaters have a higher reliability and operational safety compared to heaters that heat fuel gas directly with gas.

The main advantages of PHA heaters are their high reliability and safety.

CONCLUSION

The gas distribution station (GDS) is the main object in the system of main gas pipelines, the function of which is to reduce the gas pressure in the pipeline and prepare it for the consumer. Modern gas distribution stations are complex, highly automated and energy-intensive facilities. The operation of gas pipelines can take place in various modes, the change of which occurs when the options for switching on the units are changed. This raises the problem of choosing the most appropriate modes corresponding to the optimal loading of the gas pipeline.

With the development of electronic computing technology the automated control of GDS became possible. At present, both domestic automation systems and foreign control and measuring devices, automation and telemechanics systems are widely used at GDS facilities.

The territory of the gas distribution station must be fenced and equipped burglar alarm... The gas distribution station should be located outside the prospective development of the settlement in accordance with building codes.

Maintenance of the gas distribution station should be carried out on the basis of the "Rules for the technical operation of gas distribution stations of main gas pipelines".

In most cases, gas distribution stations were built in the middle1970s years. In general, the life of the Russian gas transmission system is approaching half a century: 14% of gas pipelines have operated for more than 33 years and require immediate replacement, another 20% are approaching this age, 37% were built 10-20 years ago and another 29% are younger than 10 years.

LIST OF USED SOURCES

1.GOST 5542-2014. Combustible natural gases for industrial and municipal purposes. - M .: 2015 .-- 12p.

2. Kantyukov R.A. Compressor and gas distribution stations. /R.A. Kantyukov, V.A. Maximov, M.B. Khadiev - Kazan: KSU im. IN AND. Ulyanov-Lenin, 2005 .-- 204s.

3. Danilov A.A. Gas distribution stations. / Danilov A.A., Petrov A.I. - SPb .: Nedra, 1997 .-- 240p.

4. Golyanov A.I. Gas networks and gas storage facilities: Textbook for universities. / A.I. Golyanov - Ufa: LLC "Publishing house of scientific and technical literature" Monograph ", 2004. - 303p.

5.GOST 21345-2005. Ball, conical and cylindrical valves for nominal pressure no more than PN 250. General technical conditions... - M .: 2008 .-- 16.

6.GOST 28338-89. Pipeline connections and fittings. Conditional passages (nominal sizes). Rows. - M .: 2005 .-- 4p.

7.GOST 26349-84. Pipeline connections and fittings. Nominal (conditional) pressures. Rows. - M .: 1996 .-- 5p.

8. Directory. Industrial gas equipment. Edition 6, revised and expanded. / Ed. E.A. Karjakina - Saratov: Scientific research center of industrial gas equipment "Gazovik", 2013. - 1280s.

9. Website. Industrial gas equipment. Gazovik company [Electronic resource] - Access mode:http: // gazovik - gaz. ru

10. Website. Purpose, scope and operating conditions of the odorizer [Electronic resource] - Access mode:http://odorizator.ru

11. GOST 15151-69. Machines, devices and other technical products. Versions for different climatic regions. Categories, operating conditions, storage and transportation in terms of the impact of climatic factors of the external environment. - M .: 2008 .-- 72s.

12. LLC Firm "SGPA". Modern equipment for gas distribution stations. Gas heater with intermediate heat carrier PGPT-3. // Oil and gas sphere. - 2010. - No. 3. - p. 48-49.

13. Rules for the technical operation of gas distribution stations of main gas pipelines. M .: - Nedra, 1982.

14. Website. Expertise of industrial safety and technical diagnostics gas distribution stations [Electronic resource] - Access mode:http://www.strategnk.ru/section/130

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1.3 Operating modes and operating parameters of the automated GDS "Energy-1"

On an automated gas distribution station, 3 control modes are possible:

Fully automatic;

Remote control of actuators from a remote operator workstation;

Remote manual and remote automatic control of actuators from the panel operator's workstation built into the ACS cabinet.

The nominal throughput of the Energia-1 station is 10,000 m3 / h at an inlet pressure of Pin \u003d 7.5 MPa and Pout \u003d 0.3 MPa.

Table 1.1 - Operating parameters of the automated gas distribution station "Energy-1"

Indicators	The values
Throughput, m3 / h
Working medium pressure, MPa: At the entrance At the exit	0,3; 0,6; 0,9; 1,2
Temperature, ° С: Environment In the premises of the GDS
Number of gas outlets
The minimum size of mechanical particles retained in filters, microns
Thermal power of the heater, kW
Gas consumption, m3 / h: For heater "PG-10" For heater "PTPG-30" For the heater "PGA-200"
Coolant pressure in the heater, MPa	Atmospheric
Heat carrier temperature, ° С
Odorizer type	Automatic with discrete feed
Overall dimensions L / W / H, mm Reduction unit Switch unit Odorization unit Instrumentation and control unit
Weight, kg Reduction unit Switch unit Odorization unit Instrumentation and control unit

1.4 Switching unit

The switching unit is designed to switch the gas flow from one line to another line of the gas pipeline, to ensure trouble-free and uninterrupted operation of the gas distribution station in cases of repair or carrying out hot and gas hazardous works. The bypass line connecting the gas pipelines of the GDS inlet and outlet is equipped with temperature and pressure measuring devices, as well as a shut-off valve and a regulator valve.

The GDS switching unit should provide for:

Cranes with pneumatic drive on gas pipelines inlet and outlet;

A plug at the GDS inlet for emergency gas discharge from process pipelines;

A bypass line connecting the gas pipelines of the GDS inlet and outlet, providing a short-term gas supply to the consumer, bypassing the GDS.

The switching unit consists of two valves (No. 1 on the inlet and No. 2 downstream gas pipelines), a bypass line and safety valves.

The valves are designed to operate at the following ambient temperatures:

In areas with a temperate climate from minus 45 to + 50 ° С;

In areas with a cold climate from minus 60 to + 40 ° С;

the relative humidity of the ambient air can be up to 98% at a temperature of plus 30 ° С.

In the absence of pressure or in the case when it is not enough to close the valve with a pneumatic hydraulic drive, the shutdown is carried out by a manual hydraulic pump. The position of the pump handle of the spool switch must correspond to the marking: "O" - opening the valve by the pump, "3" - closing by the pump, or "D" - remote control, which is indicated on the pump cover.

Ring sealing valve seats ensure tightness at pressures from 0.1 to 1.1 MPa.

The setting of spring-loaded safety valves depends on the requirements of gas consumers, but generally this value does not exceed 12% of the nominal value of the outlet pressure.

Figure 1.2 shows a gas switching unit.

Figure 1.2 - Photo of the gas switching unit

In the switching unit there is a possibility to blow through the inlet and outlet pipelines through a spark plug valve, the pipeline of which is taken out of the GDS site.

The switching unit must be located at a distance of at least 10 m from buildings, structures or technological equipment installed in an open area.

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1. Purpose and device of the gas distribution station

Gas distribution stations (GDS) are designed to reduce the high inlet pressure of natural gas, which does not contain aggressive impurities, to a given outlet pressure and maintain it with a certain accuracy. Through gas distribution stations, natural gas from main gas pipelines is supplied to settlements, industrial enterprises and other objects in a given quantity, with a certain pressure, the required degree of purification, taking into account gas consumption and odorization.

Block gas distribution station "Energy-1" provides:

Gas heating before reduction;

Gas purification before reduction;

Reducing high pressure to working pressure and maintaining it with a certain accuracy;

Gas flow measurement with registration;

Odorization of gas before delivery to the consumer.

Table 1 shows the main technical characteristics of AGDS Energia-1.

Table 1 - Technical characteristics of AGDS "Energia-1"

Characteristic	Value
Conditional inlet pressure, MPa, not more
Working pressure, MPa	from 1.2 to 5.5
Inlet gas temperature, ° C	from -10 to +20
Working gas pressure at the outlet, MPa
Accuracy of maintaining gas pressure at the outlet,%
Nominal throughput, m 3 / hour
Maximum throughput, m 3 / hour
Temperature difference at the inlet and outlet at a gas flow rate of 10,000 m 3 / hour, ° C, not less
Number of reducing threads
Odorization type	Drip

Gas distribution station AGDS "Energia-1" consists of separate functionally completed blocks. At the GDS there are units for gas heating, reduction, gas flow measurement with recording in the device memory and indication, gas odorization, heating of the control room building. The technological scheme of AGDS "Energia-1" is shown in Figure 1.

The high-pressure gas supplied to the GDS inlet passes through ball valves 2.1 and 3.1 to the PTPG-10M gas heater, where it is heated in order to prevent the precipitation of crystalline hydrates during reduction. Heating is carried out by radiation from the burner and heat from the exhaust gases. The heater has its own reduction unit, in which the fuel gas is reduced to power the burners up to 0.01 - 0.02 kgf / cm 2.

The heated high-pressure gas through the ball valves 4.1 and 4.2 enters the reduction unit, where it is preliminarily cleaned of mechanical impurities and condensate, after which it is reduced to low pressure.

From the reduction unit, low pressure gas passes to the flow line with a diaphragm installed on it. The flow measurement is carried out corrected for pressure and temperature using the Superflow IIE calculator.

After the metering unit, the gas enters the switching unit, which consists of inlet and outlet lines (ball valves 2.1 and 2.2), safety valves and a bypass line (ball valve 2.3, KMRO 2.4 regulator valve). Safety valves protect the consumer system from overpressure.

Figure 1 - Technological diagram of the gas distribution station AGDS "Energia-1"

After the switching unit, the gas enters the automatic gas odorization complex "Floutek-TM-D". Gas odorization is performed automatically according to the gas consumption. When switching the gas distribution station to bypass operation, the gas odorizer is switched to semi-automatic mode. It is also possible to odorize gas in manual mode, while control measurements of the odorant consumption are carried out using a measuring ruler according to the calibration table of the odorizer working capacity.

2 . Gas heating unit

Heating of the gas before reduction is necessary to prevent the precipitation of crystalline hydrates on the working elements of the pressure regulator.

The gas is heated in the PTPG-10M preheater, which structurally is a housing with a built-in tube bundle, a heat generator and a separation chamber. The technological scheme of the PTPG-10M gas heater is shown in Figure 1.2.

The heater body is filled with an intermediate heat carrier - a mixture of fresh water and diethylene glycol in a ratio of 2/3, respectively. The heat generator and the tube bundle are immersed in an intermediate heat carrier, the level of which is controlled by the glass of the level indicator frame.

The heater is equipped with an injection burner. A damper is installed at the air inlet to the burner, which allows to regulate the completeness of gas combustion. A flame sensor and a gas ignition burner are mounted on the shell. For manual ignition of the burner, there is a peephole into which a manual ignition burner is inserted. The gas supplied to the burner enters the nozzle holes, at the exit from which it injects the air necessary for combustion, mixes with it, forming a combustible mixture, and then burns out.

The operating principle of the heater is as follows. Fuel gas enters the heater from the low pressure gas pipeline through the gas control point and is fed to the burner where it is burned.

Figure 2 - Technological diagram of the gas heater PTPG-10M

The products of gas combustion through the heat generator enter the chimney, from where they are removed to the atmosphere. The height of the chimney ensures the dispersion of combustion products to the maximum permissible concentration. The heat of the combustion products is transferred through the walls of the heat generator to the intermediate heat carrier.

Gas from the high-pressure gas pipeline enters the first section of the separation chamber, and then into the two-pass tube bundle, where it is heated by an intermediate coolant. The heated gas returns to the second compartment of the separation chamber and enters the GDS technological scheme. Table 2 shows the main technical characteristics of the PTPG-10M gas heater.

Table 2 - Technical characteristics of the gas heater PTPG-10M

Characteristic	Value
Nominal heating capacity, Gcal / h
Nominal heated gas capacity, nm 3 / h
Working pressure in the tube bundle, MPa, not more
Pressure loss of the heated gas in the tube bundle, MPa, not more
Gas temperature, ° C: At the entrance to the heater, not less At the heater outlet, no more
Nominal gas pressure in front of the burner, MPa
Medium to be heated	Natural gas GOST 5542-87
	Natural gas GOST 5542-87
Nominal gas consumption per burner, m 3 / h
Power supply of control, alarm and protection system devices with voltage, V: AC mains From DC mains
Time of operation of protective devices for cutting off gas supply, s, no more With the simultaneous extinguishing of the flame of the main and pilot burners When there is a power outage

3 . Gas reduction unit

The gas reduction unit is an important component of the AGDS and performs its main function - the reduction of the high inlet pressure of natural gas to a given outlet pressure.

The heated high-pressure gas through taps 4.1 and 4.3 (Figure 1.3) enters the reduction unit, where it is preliminarily cleaned of mechanical impurities, after which it is reduced. The reduction block consists of two reducing threads: working and reserve. The reducing lines are equal both in terms of their equipment and throughput, which for one reducing line is 100% of the station's capacity.

4.1, 4.3 - ball valves with electro-pneumatic drive; 4.2, 4.4 - manually operated ball valves

Figure 3 - Technological diagram of the gas reduction unit

Ball valves 4.1, 4.3, located at the inlet of the reducing threads, have an electro-pneumatic drive; ball valves 4.2, 4.4, located at the outlet of the reducing threads, have a manual drive. They are designed to turn off the reducing threads if necessary.

The reduction system on each thread has two sequentially located regulators. The reduction is carried out in one stage. The protective regulator RD1, located in series with the working regulator RD2 in the working line, protects against excess of the regulated pressure during emergency opening of the working regulator. Redundant regulators, located in the reserve line, are used to prevent a drop in outlet pressure in the event of emergency closing of one of the working line regulators. The system works according to the light reserve method.

The working regulator RD2 has a setting for the station outlet pressure. The protective regulator RD1 and regulator RD3 of the reserve line located in series with it are adjusted to a pressure of 1.05 · P out and therefore, during the normal operation of the station, their control valves are in a fully open state. The RD4 regulator located in the reserve line is adjusted to a pressure of 0.95 · P out and therefore during the normal operation of the station it is in a closed state.

In the event of an emergency opening of the working regulator RD2, the outlet pressure is maintained by slightly more high level a series-located protective regulator RD1, and in the event of an emergency shutdown of one of the regulators of the working line, the outlet pressure is maintained at a slightly lower level by the reserve line.

At the energy-1 gas distribution station, pressure regulators of the RDU type are installed in the reduction unit. The technical characteristics of the regulators are shown in table 3.

Table 3 - Technical characteristics of RDU regulators

Characteristic	Value
Nominal bore, mm
Conventional pressure, kgf / cm 2
Inlet pressure, kgf / cm 2
Outlet pressure, kgf / cm 2
Coefficient of conditional throughput Ku, m 3 / h
Output pressure automatic maintenance error,%
Gas temperature, ° C	from -40 to +70
Ambient temperature, ° C	from -40 to +50
Type of connection to pipelines	Flanged
Overall dimensions, mm
Weight, kg

Pressure regulators RDU are regulators of direct action "after themselves" and are intended for automatic regulation of gas pressure at the objects of gas pipelines. In regulators of this type, a proportional-integral regulation law is implemented.

4 Gas odorization unit

The gas odorization unit is an automatic complex "Floutek-TM-D". The complex is designed to supply microdoses of odorant to the gas stream, which is supplied to the consumer, in order to impart a smell to natural gas for timely detection of leaks. Regulation of the degree of gas odorization is carried out by changing the time interval between dispensing doses of the odorant, depending on the volume of gas passing through the pipeline. The technical characteristics of the complex are shown in Table 4.

Table 4 - Technical characteristics of the "Floutek-TM-D" complex

The odorization complex functionally consists of blocks and devices.

The technological scheme of the complex is shown in Figure 1.4. Designations for the technological scheme are given in table 1.5

The odorant filling unit serves for automatic filling of the odorant working container. The gas pressure regulator and the safety valve are used to create an excess pressure (0.2-0.7 kgf / cm 2) in the odorant storage tank, sufficient to supply the odorant to the odorant filling unit.

The filling pump is designed to automatically supply the odorant to the measuring tube of the odorant flow meter. The dosing pump automatically dispenses the odorant into the gas pipeline. The odorant flow meter measures the amount of odorant discharged into the gas pipeline. Odorant intake into the gas pipeline is controlled through the sight glass of the dropper. The pumps are controlled by a controller installed in the odorization control panel.

From the control panel, you can issue a command to open or close the filling pump or to issue a series of doses with a dosing pump, a filling pump or a pump down pump.

А - odorant supply in the setting mode; B - supply of the odorant to the working container; To the pointer level; G - supply of the odorant to the dosing system of the odorization unit; D - gas for balancing

Figure 4 - Technological diagram of the FLOUTEK-TM-D complex

odorization gas reduction

The choice of the operating mode of the complex is carried out using the buttons located on the control panel of the odorization control board. When you press the "A" or "P / A" buttons on the control panel, the complex starts working in "Automatic" or "Semi-automatic" mode, respectively. The operation of the complex in both modes is similar, except for the input into the complex of the natural gas consumption value. In "Automatic" mode, the complex receives gas consumption from the gas metering system at the GDS, and in the "Semi-automatic" mode, the GDS operator enters a fixed value of the gas consumption.

The operation of the complex begins with checking the tightness of the odorant supply unit and checking the odorant leakage through the filling pump and metering pump. The filling pump H3 then pumps the odorant from the working vessel into the metering tube (IT). The IT fill time is set long enough for the IT to fill to a level equal to the setting. If the filling pump H3 fills the IT above the level of the given setting parameter, this will not affect the operation of the installation, since the calculation of the delivery of odorant doses is made according to the actual level in the IT. If the filling pump H3 does not fill the IT up to the level set by the settings, the odorization unit stops working and an error message is issued.

The PD-1 sensor of the odorant flow meter measures the odorant level in the IT. Thus, after the end of filling with IT, the complex fixes the upper level of the odorant in IT. The metering pump H1 then starts to feed the odorant from the IT into the gas pipeline. The dosage frequency of the metering pump and, therefore, the amount of odorant dispensed into the gas pipeline is proportional to the natural gas consumption. The odorant level in the IT decreases, and when the difference between the upper actual and current levels of the odorant in the IT reaches the preset value, the dosing is stopped and the odorant flow meter measures the mass of the odorant discharged into the pipeline and the subsequent period for dispensing odorant doses is adjusted. The filling pump H3 is then refilled with IT odorant to the level set in the settings.

After each filling of the IT, the level of odorant in the working tank will decrease, and when the value of this level becomes less than the set parameters (according to the LE level sensor readings), the H2 injection pump will turn on, which will pump the odorant from the odorant storage tank to the working tank. Natural gas odorization will continue. After increasing the level of odorant in the working tank above the value set by the settings, the H2 injection pump will be stopped.

There is also a manual dropper mode, in which the complex is transferred to fully manual control.

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Drawings for automation for gas mains energy 1. Automation of the gas distribution station of the Sterlitamak linear production department of the main gas pipeline. Description of the technological scheme

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