Purpose, technological diagrams and main equipment of gas control points (GRP and SHRP). How does grp differ from gru
Gas control point (GRP)
Gas control points serve to additionally purify gas from mechanical impurities, reduce gas pressure after the gas distribution station and maintain it at a given value, followed by uninterrupted and trouble-free supply to consumers.
Depending on overpressure gas inlet gas control points can be medium (up to 0.3 MPa) and high pressure (0.3-1.2 MPa). Gas distribution centers can be central (serve a group of consumers) and facility-based (serve the facilities of one consumer).
hydraulic fracturing are located:
- in separate buildings;
- built into one-story industrial buildings or boiler rooms:
- in cabinets on external walls or free-standing supports;
- on the coatings of industrial buildings of I and II degree of fire resistance with non-combustible insulation;
- in open fenced areas under a canopy
- in gasified buildings, usually close to the entrance;
- directly on the premises boiler rooms or workshops where gas-using units are located, or in adjacent rooms connected to them by open openings and having at least three air exchanges per hour. Innings gas from GRU to consumers in other separate buildings is not allowed.
Schematic diagram GRP (GRU), purpose of equipment.
Operating principle of hydraulic fracturing.
The gas passes through the inlet gas pipeline to the filter, where it is cleaned of mechanical impurities, and through protectively shut-off valve served in pressure regulator, where the gas pressure is reduced and maintained constant, regardless of flow. If the gas pressure after the regulator increases above acceptable values, for example, as a result of a malfunction of the gas pressure regulator - it is triggered protective relief valve- PSK or water seal (GZ), as a result of which excess gas pressure is released into the atmosphere. If the gas pressure continues to increase and the release of gas through the PSK does not give sufficient effect, the safety shut-off valve and gas access to the consumer through this reduction line is terminated. In order to ensure trouble-free gas supply to the consumer, even in the event of a failure of the pressure regulator, the hydraulic fracturing unit is looped along the outlet pressure, or an additional reduction line is installed in the hydraulic fracturing unit (we will return to this issue below).
It is worth noting that the hydraulic fracturing scheme (without a backup reduction line) provides a bypass line, which allows gas to be supplied and manual regulation of the gas outlet pressure during equipment repairs or maintenance hydraulic fracturing. At the entrance and exit from hydraulic fracturing pressure gauges installed. At the entrance to industrial hydraulic fracturing units or at gas metering units, the gas temperature is measured using a thermometer. For centralized measurement of gas consumption, a measuring device is installed - an industrial gas meter.
To reduce gas pressure in hydraulic fracturing pressure regulators are used directly and not direct action. In direct-acting regulators, the final pressure pulse acts on a membrane, which is connected to the throttle body through a lever device. When the output pressure decreases, the degree of opening of the throttle body increases, and when it increases, it decreases. As a result outlet pressure gas is maintained constant.
For actuating pressure regulators indirect action The energy source is compressed air and gas with a pressure of 200-1000 kPa. Indirect-acting pressure regulators are used at an inlet pressure of more than 1.2 MPa and an outlet pressure of more than 0.6 MPa. Also in lately Increasingly, combined pressure regulators are being used, which are a safety shut-off valve and a pressure regulator in one housing.
To monitor inlet and outlet pressure, room temperature, and door openings, modern hydraulic fracturing units can be equipped with a telemetry system.
GRP (GRU) provide installation: filter, safety shut-off valve PZK, gas pressure regulator, safety relief valve PSK, shut-off valves , instrumentation instrumentation, devices gas consumption metering(if necessary), as well as the device bypass gas pipeline (bypass) with the installation of two shut-off devices in series and a purge pipeline between them in case of equipment repair.
The second shut-off device along the gas flow bypass should provide smooth regulation.
For hydraulic fracturing with an inlet pressure of more than 6 kgf/cm 2 and a throughput capacity of more than 5000 m 3 /h, instead of bypass provide an additional reserve control line.
Installation PZK provide before pressure regulator. PZK designed to automatically shut off the gas supply at the hour of increase or decrease in gas pressure after the regulator above the established limits.
According to the requirements of the regulations, the upper limit of operation PZK must not exceed the maximum working pressure gas after the regulator by more than 25%. The lower limit set by the project meets the requirements for ensuring sustainable operation gas burner devices, and is specified during commissioning.
Installation PSK must be provided for pressure regulator, and if available flow meter- after the flow meter.
PSK must ensure the release of gas into the atmosphere, based on the conditions of a short-term increase in pressure that does not affect industrial safety and normal operation gas equipment consumers.
Before PSK provide disconnecting devices that must be sealed in the open position.
Safety relief valves must ensure gas discharge when the rated operating pressure after the regulator is exceeded by no more than 15%.
Rule requirements for setting the response limit PSK-15% and upper response limit PZK- 25% determine the order (sequence) of valve actuation first PSK,then PZK.
The expediency of this order is obvious: PSK, preventing a further increase in pressure by releasing part of the gas into the atmosphere, does not disrupt the operation of boilers; when triggered PZK boilers turn off abnormally.
Fluctuations in gas pressure at the outlet hydraulic fracturing allowed within 10% of operating pressure. Malfunctions of regulators causing an increase or decrease in operating pressure, malfunctions safety valves, as well as gas leaks must be eliminated in an emergency manner.
Getting started pressure regulator in the event of a gas supply interruption, it must be carried out after identifying the reason for the operation of the safety shut-off valve PZK and taking corrective action.
IN hydraulic fracturing purge and discharge pipelines should be provided that lead outside to places that provide safe conditions for gas dispersion, but not less than 1 m above the eaves or parapet of the building.
It is allowed to combine purge pipelines of the same pressure into a common purge pipeline. The same requirements apply when combining waste pipelines.
IN hydraulic fracturing install indicating and recording instrumentation instrumentation(12) to measure inlet and outlet pressure and gas temperature. If gas consumption is not recorded, it is permissible not to provide a recording device for measuring gas temperature.
The accuracy class of pressure gauges must be at least 1.5.
A three-way valve or similar device must be installed in front of each pressure gauge to check and disconnect the pressure gauge.
The main purpose of gas control points (GRP) and installations (GRU) is to reduce the inlet gas pressure (throttling) to a given output and maintain the latter at a controlled point in the gas pipeline constant (within specified limits) regardless of changes in inlet pressure and gas consumption by consumers. In addition, the gas distribution center (GRU) performs: gas purification from mechanical impurities, monitoring inlet and outlet pressure and gas temperature, flow metering (if there is no specially designated flow measurement point), protection against a possible increase or decrease in gas pressure at the controlled point of the gas pipeline beyond permissible limits. The presence of constant pressure in the gas supply system (in a predetermined range of its fluctuation) is one of the most important conditions safe and reliable operation of this system and gas-consuming objects and units connected to it.
GRP and GRU are equipped with almost the same equipment and differ from each other mainly in their location.
The GRU is mounted directly in the premises where the units using gas fuel(workshops, boiler rooms, etc.).
GRPs are placed depending on the purpose and technical feasibility: in separate buildings; in extensions to buildings; on fireproof coating industrial building where gas consumers are located; in cabinets installed on a fireproof wall outside the building being gasified, on a separate fireproof support or (if there are support posts) on a concrete foundation.
Scheme of hydraulic fracturing with regulator RDUK2
Let's consider the hydraulic fracturing circuit with the RDUK2 regulator in Figure 1:
1 - input; 2 - locking device; 3 - tap; 4 - tap; 5 - filter; 6 - shut-off valve; 7 - pressure regulator; 8 - pressure regulator with pilot; 9 - locking device; 10 - rotary elbow; 11 - valve; 12 - impulse pipeline; 13 - output; 14 - locking device; 15 - locking device; 16 - fitting; 17 - dog; 18 - discharge pipeline; 19 - valve; 20 - counter; 21 - valve; 22 - filter revision; 23 - technical thermometer; 24 - recording thermometer; 25 - self-recording pressure gauge; 26 - pressure gauge; 27 - second locking device; 28 - pressure gauge; 29 - tap; 30 - locking device; 31 - discharge pipeline; 32 - fitting; 33 - pressure gauge; 34 - recording pressure gauge; 35 - differential pressure gauge.
Figure 1 - Diagram of hydraulic fracturing (GRU) with RDUK2 regulator and gas flow measurement with rotary meters.
Let's consider the diagram in Figure 1 of a single-stage hydraulic fracturing unit (GRU), which has one production line taking into account gas flow by two rotary meters and is equipped with a pressure regulator RDUK2. General shut-off devices are installed outside the gas distribution unit at input 1 and output 13 (shown by dashes). For purging gas pipelines located up to 240.
In the hydraulic fracturing, there is a discharge pipeline 31, which is connected to the main gas pipeline at point B or A, depending on design features Hydraulic fracturing. In the first option, for purging, the first shut-off device 30 along the gas flow is opened on the bypass and valve 29 at the outlet to the discharge pipeline; in the second option, only valve 29 is opened. Connection 32 is used to take a sample when monitoring the end of the purge. On the bypass there is a second shut-off device 27 and a pressure gauge 28. The pressure gauge 33 is designed to measure the inlet pressure, and a recording pressure gauge 34 is used to record it. To turn on and off the main equipment: filter 5, shut-off valve 6 and pressure regulator 7, shut-off devices 2 and 9 are used The section of the gas pipeline between valve 2 and filter 5 is connected by an outlet to valve 3 with discharge pipeline 31. This allows the gas pressure to be reduced in technological line with shut-off devices 2 and 9 closed to atmospheric pressure, which must be done before cleaning the filter and repairing the slam-shut valve and regulator. With an inlet pressure of up to 3 kgf/cm2 and a process line diameter of Dy^L100 mm, it is permissible not to provide for gas discharge from this section. The pressure drop across the filter mesh or cassette is determined using a differential pressure gauge 35, on the impulse tubes of which there are valves 4. If the inlet pressure does not exceed 2.5 kgf/cm2, then it is possible to use an indicating pressure gauge instead of a differential pressure gauge with a division value of no more than 0.05 kgf /cm2. A recording thermometer 24 and a pressure gauge 25 record the temperature and pressure of the gas before the meters, which makes it possible to introduce appropriate corrections to the readings of the latter. In addition to the recorder, it is usually also necessary to install a technical thermometer 23, the lower part of which is located in a special cavity of the gas pipeline next to the sensor of the recorder thermometer. If the consumer's gas consumption is small and one rotary meter is used to measure it in the GRU, then often only a technical thermometer is used, the lower part of which is inserted into the hole in the upper cover of the inspection filter 22, using an appropriate seal or welding a sleeve to it. The impulse pipeline 12 is connected to the output gas pipeline at point G. From it, branches are provided with taps to the indicating pressure gauge 26, as well as to the shut-off valve and pressure regulator with pilot 8. The supply pipeline to the PSU 17 with a shut-off device 15 can also be connected to it, normally sealed and closed. Fitting 16 is intended for setting up the PSU, and for releasing gas into the atmosphere through the PSU - discharge pipeline 18. Switching off and turning on meters 20 is done with valves 21. If it is necessary to work without meters (inspection, repair), open valve 19, which should normally be sealed in a closed position A revision filter 22 is installed in front of the meter, and a rotary elbow 10 is installed after it.
Elements of hydraulic fracturing and hydraulic control unit
In accordance with their purpose, the GRP and GRU include the following elements:
1) A pressure regulator (PR), which reduces gas pressure and maintains it at a controlled point at a given level, regardless of gas flow and changes in input pressure within certain limits.
2) A safety shut-off valve (SSV), which stops the gas supply when its pressure after the regulator increases or decreases above the specified limits. On industrial enterprises where, due to production conditions, interruptions in the gas supply are not allowed (for example, in power plants), SCPs are not installed, and to prevent accidents, an alarm is provided for an increase or decrease in gas pressure above established limits.
3) A safety relief device (SDU), which discharges excess gas from the gas pipeline after the regulator so that the gas pressure at the controlled point does not exceed the specified one.
4) Filter for purifying gas from mechanical impurities. Installation of a filter is not necessary in a gas distribution unit, to which gas is supplied through a gas distribution unit or a centralized gas purification point of the enterprise and the distance from which to the gas distribution unit or purification point does not exceed 1000 m.
5) Instrumentation (instrumentation) for measuring: gas pressure before and after the regulator, as well as on the bypass gas pipeline - indicating pressure gauges (if necessary, recording); pressure drop across the filter
6) differential pressure gauge; accounting for gas flow in the hydraulic fracturing unit or gas distribution unit (if necessary) - flow meters; gas temperature in front of the flow meter - indicating and recording thermometers.
7) Pulse pipelines for connecting the regulator, shut-off valve, PSU and instrumentation with those points on the gas pipelines at which the gas pressure and temperature are controlled.
8) Discharge pipelines for releasing gas into the atmosphere from the PSU, purge lines, etc.
9) Shut-off devices for turning on and off the regulating and safety equipment, as well as instrumentation. The number and location of shut-off devices must ensure the possibility of shutting off the main equipment and the necessary instrumentation for inspection and repair of the gas distribution unit (GRU) without stopping the gas supply to consumers.
10) Bypass gas pipeline (bypass) with two shut-off devices to supply gas to consumers through it during inspection and repair, as well as emergency condition equipment installed on the main production line. In a cabinet-type gas distribution unit, a bypass device is not necessary.
Depending on the gas pressure at the inlet, hydraulic fracturing and gas distribution units are divided into:
Medium-pressure hydraulic fracturing and gas distribution unit (more than 0.05 to 3 kgf/cm2);
Hydraulic fracturing and high pressure gas distribution unit (more than 3 to 12 kgf/cm2).
70. Gas distribution point (GDP) and installations (GRU).
Gas control points - serve for additional purification of gas from mechanical impurities, reducing gas pressure after the gas distribution station and maintaining it at a given value, followed by uninterrupted and trouble-free supply to consumers. Depending on the excess gas pressure at the inlet gas control points can be medium (up to 0.3 MPa) and high pressure (0.3-1.2 MPa). Gas distribution centers can be central (serve a group of consumers) and facility-based (serve the facilities of one consumer).
Types of hydraulic fracturing.
GRPs are divided among themselves: by outlet pressure : Hydraulic fracturing of low, medium and high output pressure. by the number of gas pressure reduction stages : single-stage and multi-stage hydraulic fracturing. by the number of reduction lines : single-line and multi-line hydraulic fracturing. according to the type of gas supply scheme for the gas consumer : dead-end and looped hydraulic fracturing. by the presence of a reserve reduction thread : hydraulic fracturing with and without backup reduction line.
Gas distribution plant(GRU) is a system of technological equipment that provides pressure reduction, cleaning and accounting of gas flow before supplying it to the gas distribution network.
GRUs ensure the supply of gas from main gas pipelines and branches to populated areas, industrial and agricultural enterprises in a given quantity.
Operating conditions of the gas distribution unit:
outdoor location
areas with seismicity up to 8 points
temperate climate with temperatures from -40 to +50 °C and cold climate with temperatures from -60 to +50 °C
Main functions of the gas distribution plant:
reducing high pressure gas to a specified low pressure and maintaining it with a certain accuracy;
the gas distribution unit ensures gas heating before reduction;
automatic control of operating modes of the station's process equipment, including limitation of gas supplies according to the requirements of the gas distribution organization (GDO);
issuing emergency and warning signals in case of malfunctions to the control panel to the dispatcher or operator;
measurement of gas consumption with multi-day data recording and transfer of information to the level of the gas distribution organization;
In the gas distribution unit, gas is purified from droplets of moisture and mechanical impurities.
Operating principle of the gas distribution plant
Moving along a common pipeline, high or medium pressure gas enters the gas distribution unit through the inlet valve. First, the gas is purified in a filtration system and enters a rotary gas meter with an electronic corrector to track the exact amount of substance entering the installation. After this, the gas enters the pressure regulator, in which its pressure is reduced and maintained at the required level. The gas is then directed to the consumer through the outlet valve.
71. Maintenance of gas supply systems. Safety precautions during the construction and operation of gas supply systems.
Combustible gases mixed with air explode at certain concentrations and temperatures. Some flammable gases are toxic, so personnel carrying out repairs must master the techniques and methods of working on gas pipelines and equipment under gas pressure, and when eliminating flammable gas leaks, use personal protective equipment. Gas hazardous work is considered to be work that is carried out in a gas-polluted environment or in which flammable gas may escape from gas pipelines, vessels and units, which may result in poisoning of people, an explosion or ignition of the gas.
Gas hazardous work includes: connection of newly built gas pipelines to existing ones without disconnecting them from the gas network (“gas connection”); commissioning of gas pipelines, hydraulic fracturing (GRU) and gas networks; repair of existing gas pipelines; inspection and repair of existing gas pipelines in wells, tunnels, etc. without disconnecting them from gas; cleaning of gas pipelines; equipment repair; gas control points; dismantling of gas pipelines disconnected from existing gas networks; filling tanks and cylinders with liquefied gas; preventive maintenance of both existing gas appliances and internal gas equipment.
Only persons who have passed the technical minimum exam and have experience working “under gas” are allowed to work, and only after receiving a work order.
The size (composition) of the team for carrying out gas-hazardous work is determined depending on the volume of work, but must be at least 2-3 people. One of them is appointed senior.
When performing work in enclosed spaces (basement, hydraulic fracturing, tunnel, well, etc.), you must first thoroughly ventilate it and take an air sample for analysis. The absence of gas impurities in the air serves as the basis for starting work.
If it is impossible to create conditions that exclude the possibility of gas evolution at the workplace, then work is carried out in hose or insulating gas masks. When working in a well or trench, the worker must be equipped with a safety belt with a rope, one end of which is on the surface of the ground for the person observing the work.
Electric welders of 4-6 categories are allowed to perform gas cutting work when connecting to existing gas pipelines.
During repair work in the GRP premises, the worker must be under continuous supervision from the street. When working on hydraulic fracturing in gas masks, it is necessary to ensure that the hoses do not have fractures, and their open ends are located outside the building on the windward side. When performing repair work, it is necessary to use a tool whose use eliminates the possibility of spark formation.
Preventive examination gas stoves and high-speed water heaters are carried out once every two months. Gas appliances with automation once a month. Preventative maintenance of cylinder and tank liquefied gas installations is also carried out regularly according to schedule.
During construction, all safety requirements must be observed.
Purpose, device, classification
gas control points
GRP, ShRP, GRPSh, GSGO, GRPSHN, PHB, UGRSH, GRPB .
Gas control points (installations) are a complex of technological equipment and devices. The purpose and design of gas control units (GRU, GRP, GRPSh) are provided for pre-cleaning gas, automatic reduction of gas pressure and maintaining it at specified levels regardless of changes in gas flow within the nominal flow characteristics of gas pressure regulators, control of inlet and outlet pressures and gas temperature. And also gas control points can accurately record the gas consumption of smoothly varying flows of non-aggressive gases. Depending on the purpose and technical feasibility, gas control equipment will be placed in separate buildings, in extensions to buildings, and in cabinets. Depending on the placement of equipment, gas control points are divided into several types:
*
gas stations with gas heating (GSGO) - the equipment is placed in a cabinet made of fireproof materials;
* cabinet gas control unit (GRPSH) - the equipment is placed in a cabinet made of fireproof materials;
*
cabinet control point (SRP) - the equipment is placed in a cabinet made of fireproof materials;
* gas control unit (GRU) - the equipment is mounted on a frame and placed in the room in which the gas-using unit is located, or in a room connected to it by an open opening;
* block gas control point (GBP) - equipment is installed in one or more container-type buildings;
* stationary gas control point (GRP) - equipment is located in specially designed buildings, premises or open areas.
The fundamental difference between hydraulic fracturing and GRPS, ShRP , GRU And PHB is that hydraulic fracturing (unlike the latter) is not a standard product of full factory readiness.
Installation of hydraulic fracturing in basements and semi-basements of buildings, in extensions to buildings of schools, hospitals, child care institutions, residential buildings, entertainment and administrative buildings not allowed.
Consider the device hydraulic fracturing with bypass line. The bypass line is used to manually regulate gas pressure during the period of repair (replacement) of equipment on the main line and consists of a pipeline with two shut-off devices (valves) equipped with a pressure gauge for measuring pressure. The main line consists of the following equipment connected in series by pipelines: input disconnect device; gas filter ( FS, FG), which cleans the gas from mechanical impurities and is equipped with pressure gauges for measuring the pressure drop (the readings of the pressure gauges indicate the degree of filter contamination); safety shut-off valve that shuts off the pipeline in case of pressure beyond the specified limits after the regulator (controlled through the impulse tube) (BULLPEN) ; gas pressure regulator, lowering the pressure to the required (RDBK, RDNK) ; output disconnecting device; a safety relief valve that releases gas into the atmosphere in the event of a short-term increase in pressure above the set one. To configure PSK a locking device must be installed in front of it. Detailed description The operation of all described devices can be found in the corresponding sections.
Gas control points and installations can be classified as follows.
By number of outputs:
* gas control points and installations with one outlet;
* gas control points and installations with two outlets.
According to technological schemes:
* gas control points with one reduction line (house);
* gas control points with one reduction line and bypass;
* gas control points with main and backup reduction lines;
* gas control points with two reduction lines;
* gas control points with two reduction lines and a bypass (two bypasses).
In turn, cabinets and installations with two reduction lines according to the regulator installation diagram are divided into:
* gas control points and installations with sequential installation of regulators;
* gas control points and installations with parallel installation of regulators.
Based on the output pressure provided, they are divided into:
* gas control points and installations that maintain the same pressure at the outlets;
* gas control points and installations that maintain different pressures at the outlets.
Cabinets and installations that maintain the same pressure at the outlets can have the same or different capacity of both lines. Cabinets with different capacities are used to control seasonal gas supply modes (winter/summer).
When choosing cabinets and installations, the operating parameters provided by the gas pressure regulator are basic (inlet and outlet pressure, throughput), therefore one should be guided “Basic principles for selecting regulators.” It should not be forgotten that the output parameters of cabinets and installations differ, sometimes significantly, from the output parameters of regulators. Gas control points and installations with gas flow metering units are manufactured to order. Depending on the gas pressure at the inlet of hydraulic fracturing (GRU), there are medium (more than 0.005 to 0.3 MPa) and high (more than 0.3 to 1.2 MPa) pressures.
Gas control units (GRP, ShRP, GRPSh, GSGO, GRPSHN, PGB, UGRSh, GRPB) contain the following equipment:
a pressure regulator that automatically reduces gas pressure and maintains it at a controlled point at a given level;
safety shut-off valve that automatically stops the gas supply when its pressure increases or decreases beyond specified limits ( installed in front of the regulator along the gas flow);
a safety relief device that discharges excess gas from the gas pipeline behind the regulator into the atmosphere so that the gas pressure at the controlled point does not exceed the specified value. It is connected to the outlet gas pipeline, and if there is a flow meter (meter) - behind it (a shut-off device is installed in front of the discharge);
filter for purifying gas from mechanical impurities. Installed in front of the safety shut-off valve
bypass gas pipeline (bypass) with two shut-off devices located in series (gas is supplied through the bypass during inspection and repair of the equipment of the reduction line, its
the diameter is assumed to be no less than the diameter of the regulator valve seats). For hydraulic fracturing with an inlet pressure above 0.6 MPa and a throughput capacity of more than 5000 me/h, an additional reserve control line is installed instead of a bypass.
The following measuring instruments are used in the hydraulic fracturing unit: gas pressure in front of the regulator and behind it (indicating and recording pressure gauges); pressure drops across the filter (differential pressure gauges or technical pressure gauges); gas temperature (indicating and recording thermometers). In the GRP (GRU). in which gas flow is not taken into account, it is allowed not to provide recording devices for measuring temperature.
Impulse tubes serve for connection to the regulator, shut-off and relief valves and connection of measuring instruments.
Discharge and purge pipelines used for releasing gas into the atmosphere from a discharge device and for purging gas pipelines and equipment. Purge lines
placed on the inlet gas pipeline after the first shut-off device; on the bypass between two shut-off devices; on a section of a gas pipeline with equipment that is switched off for
inspections and repairs. The nominal diameter of the purge and discharge pipelines is taken to be at least 20 mm. Purge and discharge pipelines are led outside to places that ensure safe dispersion of gas, but not less than 1 m above the eaves of the building.
Locking devices must ensure the ability to turn off the gas distribution unit (GRU), as well as equipment and measuring instruments without stopping the gas supply.
Hydraulic fracturing (GRU) can be one-stage or two-stage. In single-stage, the input gas pressure is reduced to the output by one, in a two-stage - by two in series established regulators. In this case, the regulators must have approximately the same performance at the corresponding inlet gas pressures.
Single-stage schemes are usually used when the difference between the inlet and outlet pressure is up to 0.6 MPa.
The pulse sampling locations for the pressure regulator and safety shut-off valve are determined by the equipment manufacturer's data sheet, but may vary.
The layout diagram of hydraulic fracturing equipment (GRU) is shown on rice. 1,
To supply consumers with gas consumption up to 2000 m3/h, a cabinet gas control unit (GRPSh) or gas stations with gas heating (GSGO) are used.
Source: gazapparat.ucoz.ru
Influenza A - what is it? Influenza A and B: symptoms and treatment
Influenza got its name from French word“grasp”, which well characterizes its action.
This disease develops rapidly. Even in the morning, a healthy person begins to complain about his health at noon, and by midnight, in some cases, he may no longer have a chance of recovery.
Historical facts
Flu epidemics periodically cover the entire space globe and become historical fact. For example, more people died from the Spanish flu in 1918 and 1919 than during the entire First World War.
The pathogen believed to cause influenza was discovered in 1933 and subsequently named virus A.
The year 1944 was marked by the discovery of virus B, the next one, virus C, was discovered in 1949. Over time, it was determined that the viruses that cause influenza A and B are heterogeneous, constantly changing, and as a result of these transformations, influenza of a new modification can appear.
What is the flu
I wonder what influenza A or B is. This is an acute infectious disease that begins almost instantly. Viruses immediately attack the mucous membrane of the respiratory tract. Because of this, a runny nose appears, the paranasal sinuses become inflamed, the larynx is affected, breathing is impaired and a cough develops.
The virus travels through the body in the blood and, poisoning it, disrupts vital functions:
- rises high temperature, often accompanied by nausea and vomiting;
- headaches and muscle pain occur;
- and in some cases, hallucinations may begin.
The most severe situations are characterized by intoxication, which leads to damage to small vessels and multiple hemorrhages. The consequences of the flu can include pneumonia and heart muscle disease.
Influenza A and B are types of acute respiratory diseases. When the disease occurs, a person’s defense mechanism is disrupted. Under the influence of microbes that are in the upper respiratory tract, cells in the trachea and bronchi die, opening the way for infection in deeper tissues and making the process of cleansing the bronchi more difficult. This suppresses the function of the immune system. Because of this, a short period of time is enough for the onset of pneumonia or the awakening of other respiratory viruses.
How is it transmitted?
A person is susceptible to diseases such as influenza A and B. This means that there is a high probability of getting sick for the second and third time, especially with a new subtype. The disease is transmitted as follows:
- during communication with a sick person, through drops of saliva, mucus, sputum;
- together with food that has not been thermally processed;
- when directly touching the patient with your hands;
- through the air, through dust.
The patient is enveloped like a ball by a zone consisting of infected particles, its size is from two to three meters. Through any objects that were in his hands (for example, a telephone, the armrest of a chair, door handle) you can catch influenza A.
Everyone should know that this is a contagious disease - a person poses a danger to others even during the incubation period, even before he feels unwell. True, on the sixth day from the onset of the disease, it practically does not pose a threat to the health of others.
Influenza A virus
So, influenza type A - what is it? This is one of the most terrible types of this disease. The immunity acquired by a person who has had influenza type A lasts two years. Then he becomes dangerous again.
Interestingly, an exchange of hereditary materials can occur between human and animal viruses, and viral hybrids can arise upon contact. As a result, the flu can affect not only humans, but also animals.
About once every 35 years significant changes The virus that causes influenza type A is also exposed. It is better not to know what it is. After all, humanity does not have immunity to this serotype, as a result of which the disease affects most of the world's population. It occurs in a very severe form. And in this case they are not talking about an epidemic, but about a pandemic.
Symptoms and features of the course
It should be mentioned when talking about influenza type A that this is a disease that is characterized by rapid spread. The incubation stage lasts from two to five days, and a period begins that is characterized by acute clinical manifestations.
For influenza occurring in mild form, it lasts from three to five days. And after 5-10 days the person recovers. But for another 20 days a person may feel tired, weak, and experience headache, be irritable and suffer from insomnia.
Here is a list of the symptoms influenza A causes in children:
- the temperature rises to 40 °C;
- the child is shivering;
- the baby stops playing, whines, and becomes very weak;
- complains of headache and muscle pain;
- his throat hurts;
- possible abdominal pain and vomiting;
- a dry cough begins.
Treatment
During periods of elevated temperature, a person loses a lot of fluid, which needs to be replenished. The first thing to do during illness is to drink plenty of tea, drinks, and herbal decoctions. Has a good effect on the course of the disease chicken broth. By increasing the rate of mucus secretion, it reduces nasal swelling.
Drinking coffee and alcohol causes dehydration of the body, which has already lost a lot of fluid, so it is better not to drink them during illness.
Why is influenza A dangerous?
Almost everyone knows what the flu is. But the opinion that this is a common disease that everyone has had many times without consequences is wrong. Its main danger lies in the consequences it can cause: pneumonia, rhinitis, sinusitis, bronchitis. It can aggravate chronic diseases, provoke cardiovascular complications, and create problems with the muscular system.
By the way, influenza type A, unlike the disease caused by virus B, is more dangerous. As a result of this disease, intoxication, hemorrhages in important organs, pulmonary complications, heart and cardiopulmonary failure can lead to death.
Prevention
To avoid being among those infected, each of us needs to follow preventive measures that can prevent influenza. What is this? First of all, the basic principles should be observed healthy image lives such as proper nutrition and uniform physical activity. Hardening is also important.
Vaccination helps the body build immunity to the most expected strain of the virus. The drug is administered 1-3 months before the expected start of the epidemic.
A cotton-gauze bandage reduces the likelihood of infection through the respiratory tract. The dressing is changed several times a day to avoid infection from the dressing itself.
Here are some more prevention tips:
- Taking vitamin supplements increases protective functions body.
- Garlic reduces the number of microorganisms in the oral cavity.
- Avoiding visiting crowded places during an epidemic reduces the likelihood of infection.
- During an epidemic, it is advisable to wet clean the premises daily.
- Treatment of the nasal cavity with oxolinic ointment helps protect against microbes.
- The use of antiviral drugs protects against the disease.
If there is a sick person in the house
Despite some differences, doctors still combine influenza A and B (symptoms and treatment). First of all, it is recommended to give the body a chance to rest. Due to this, you will help the immune system. Necessary Requirement- compliance with bed rest. And the most important thing is to call a doctor at home, because it may not be the flu, but what it is is impossible to say without an examination by a specialist.
In order to reduce the possibility of infecting family members, the patient is placed in a separate room or fenced off from the main room. The patient is provided with separate dishes and hygiene items.
Necessary and wet cleaning with disinfectants, since thanks to it the concentration of viruses drops by more than half. Good healing effect provides ventilation at least 3 times a day.
Source: fb.ru
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Gas control points
Gas control points
Gas control points (GRP) or installations (GRU) are designed to: reduce gas pressure to a given value; maintaining a given pressure regardless of changes in gas flow and pressure at the inlet to gas control points or gas control units; stopping the gas supply when its pressure increases or decreases after hydraulic fracturing or gas distribution in excess of established standards.
The difference between GRU and GRU is that the former are built directly at consumers and are intended to supply gas to boilers and other units located in only one room, while gas control points are equipped at city gas distribution networks or municipal facilities. Schematic diagrams GRP and GRU are similar.
Gas control equipment can be located in a separate building, in a room built into the boiler room, or in metal cabinets outside the building. In the latter case, the installation is called “cabinet gas control points” (GRP). Lightning protection of the gas distribution facility is necessary in cases where the gas distribution building does not fall within the lightning protection zone of neighboring facilities. In this case, a lightning rod is installed. If the GRP building is located in the lightning protection zone of other facilities, then only a grounding loop will be installed in it. The fracking room is equipped with firefighting equipment and devices (a box of sand, fire extinguishers, fire felt, etc.).
Gas hydraulic fracturing equipment. The hydraulic fracturing equipment set includes: a filter for purifying gas from mechanical impurities; a safety shut-off valve that automatically turns off the gas supply to consumers in the event of a failure of the gas pressure regulator; gas pressure regulator, which reduces gas pressure and automatically maintains it at a given level; safety-relief valve (hydraulic or spring) at the gas outlet, which ensures the release of excess gas in the event of an increase in gas pressure above the permissible f- (working) at the outlet of the GRN. and pressure gauges for measuring gas pressure at the inlet and outlet of the hydraulic fracturing system.
The main line on which the gas equipment is located is equipped with a bypass gas pipeline (bypass) with two valves, with the help of which, in the event of a malfunction in the main line, the gas pressure is manually regulated. Rotary meters are installed at the outlet gas control points of small capacity to measure the amount of gas consumed. To vent gas, purge gas pipelines (candles) are installed. The placement of hydraulic fracturing equipment is shown in Fig. 79.
Types of pressure regulators, pressure regulators are the main devices of hydraulic fracturing. They differ in size, design, range of input and output pressures, methods of setting, adjustment, etc. Gas pressure regulators are divided into regulators: direct action, using gas energy in the gas pipeline; indirect action, operating on energy from external sources (pneumatic, hydraulic and electrical); intermediate type, using gas energy in gas pipelines equipped with amplifiers, like indirect-acting regulators.
Direct-acting regulators are most widely used in gas supply systems for heating boiler houses, as they are the simplest and most reliable in operation. In turn, these regulators are divided into pilot and unmanned. Pilot regulators have a control device (pilot) and are different from unmanned ones large sizes and throughput.
The main structural unit of all direct-acting regulators is the valve. Regulator valves can have a hard seal (metal to metal) or a soft seal (rubber and leather); valves with a soft seal will more accurately withstand the set pressure behind the regulator. The flow capacity of the regulator depends on the size of the valve and the size of its stroke, therefore one or another design of the regulator is selected according to the maximum possible gas consumption, as well as the size of the valve and the size of its stroke. The cross-sectional area of the seat is 16-20% of the cross-sectional area of the inlet fitting. The maximum distance that the valve can extend from the seat is 25-30% of the diameter of its seat. The throughput of the regulator also depends on the pressure drop, i.e., on the pressure difference before and after the regulator, gas density and final pressure. In the instructions and reference books there are tables of the capacity of the regulators with a difference of 1000 mm of water. Art. To determine the capacity of the regulators, it is necessary to do a recalculation. Some of the most common types of RD and RDUK regulators are discussed below.
RD regulators. They are used for low-capacity hydraulic fracturing and are unmanned. They are marked by nominal diameter: RD-20, RD-25. RD-32 and RD-50.
the maximum throughput of gas of the first three types is 50 m 3 / h and the last one is 150 m 3 / h.
The first three types have the same overall dimensions and differ only in the connecting dimensions of the inlet and outlet pipes. RD-20 regulators are not manufactured.
Recently, modernized regulators RD-32M and RD-50M have been released, each having two inlet fittings. The design and principle of operation of these regulators are the same. In Fig. 80 shows the device of the RD-32M regulator.
The principle of its operation is as follows: as gas consumption decreases, the pressure after the regulator begins to increase. This is transmitted by impulse tube under the membrane. The membrane, under gas pressure, goes up, compressing the spring until the forces of gas pressure and the spring are balanced. The upward movement of the membrane is transmitted by a system of levers to the valve, which covers the hole for the passage of gas. As a result, the gas pressure decreases to a predetermined value.
As gas consumption increases, the pressure after the regulator begins to drop. This is transmitted through an impulse tube under the membrane, which, under the action of a spring, goes down, and through a system of levers the valve opens. The passage for gas increases, and the gas pressure after the regulator is restored to the set value. The capacity of the RD-32M and RD-50M regulators is 190 and 780 m/h. RDUK regulators. In operation, regulators RDUK-2-50, RDUK-2-100 and RDUK-2-200 are used, which differ from one another in the nominal diameter of 50, 100 and 200 mm, respectively. The maximum flow rates of these regulators are 6600, 17850 and 44800 m/h.
RDUK regulators (Fig. 81) are installed complete with regulators (pilots) KN-2 ( low pressure) and KV-2 (high pressure). To obtain a gas outlet pressure in the range of 0.5-60 kPa (50-6000 mm water column), a KN-2 pilot is used, and in the range of 0.06-0.6 MPa (0.6-6 kgf/cm) - KV-2 pilot.
The operation of the RDUK regulator is carried out as follows: as gas consumption decreases, the pressure after the regulator begins to increase. This is transmitted through impulse tube 1 to the pilot membrane, which, moving down, closes the pilot valve. The passage of gas through the pilot through impulse tube 2 stops, so the gas pressure under the regulator membrane also drops. When the pressure under the RDUK membrane becomes less than the mass of the plate and the pressure exerted by the regulator valve, the membrane will go down, displacing gas from under the cavity membrane through impulse tube 3 to the discharge. The valve begins to close, reducing the opening for gas passage. The pressure after the regulator will decrease to the set value.
As gas consumption increases, the pressure after the regulator begins to fall. This is transmitted through the impulse tube to the membrane to the pilot. The pilot membrane goes up under the action of the spring; open the pilot valve; gas from the high side flows through impulse tube 2 to the pilot valve and then through impulse tube 3 goes under the regulator membrane. Part of the gas is discharged through impulse tube 4, and part under the membrane.
The gas pressure under the regulator membrane increases and, overpowering the mass of the load plate and the force of the valve, forces it to move upward. The regulator valve opens, increasing the opening for gas passage. The pressure after the regulator increases to the specified value.
When the gas pressure in front of the regulator increases above the established norm, the latter operates similarly to the operation of this device when gas consumption decreases. Regulator safety devices. These devices are installed in front of the gas pressure regulator. Their membrane head is connected to a final pressure gas pipeline through an impulse tube. When the operating gas pressure increases or decreases above or below the established standards, safety shut-off valves automatically cut off the gas supply to the regulator.
Safety-relief devices used in gas control points ensure the release of excess gas in the event of loose closing of the safety-shut-off valve or regulator. Safety-relief devices are installed on the outlet pipe of the gas pipeline (after the regulator) and connected to a separate spark plug using the inlet fitting. When the gas pressure increases above the established norm, its excess is discharged into the spark plug.
The permissible increase in inlet pressure to which the relief device is set must be less than for the safety shut-off valve.
Safety shut-off valve. The most common of them are low-pressure (PKN) and high-pressure (PKV) safety valves. The PKV safety shut-off valve (Fig. 82) has inlet and outlet flanges on the body. Inside the body there is a seat on which a valve with a soft seal sits on top.
The equalizing valve of the PKV is built into the body of the main valve, which is why it differs from the old PKV design. To raise the main valve, I first open the equalizing valve. Gas, entering under the main valve through the equalizing valve, equalizes the pressure before and after the main valve, which then easily rises.
A system of levers connects the main valve to a sensing head located on top of the PCV, which operates these levers to close the valve. As a result, the valve is additionally pressed against the seat by gas pressure. The sensitive part of the head is a membrane, on which a load presses from above, and from below gas, flowing through the impulse tube from the low pressure side. There is a spring located above the membrane, which does not act on the membrane, which is in its normal middle position.
When lifted up, the membrane rests against the spring. As it rises further, the spring begins to compress, counteracting the movement of the membrane. The compression of the spring can be adjusted by a glass located in the upper part of the head. The membrane rod is connected by a horizontal lever to a hammer. The safety shut-off valve operates as follows: an increase in pressure above the permissible value in the gas pipeline (after the regulator) is transmitted through an impulse tube under the PCV membrane, which rises upward, overcoming the weight of the load and the resistance of the spring. The horizontal lever connected to the diaphragm rod comes into motion and disengages from the hammer. The hammer falls and hits the lever connected to the main valve rod, which closes, blocking the gas passage.
A decrease in pressure above the permissible value in the gas pipeline (after the regulator) is transmitted through the impulse tube under the membrane, which begins to fall under the influence of the load. In this case, the adhesion of the horizontal lever to the hammer is again broken. The hammer falls and the main PCV valve closes. Low pressure safety valve PKN differs from safety valve high pressure PKV in that it does not have a support ring limiting the working surface of the membrane. In addition, the plate on the membrane of the PKN has a larger diameter.
Discharge safety devices. An increase in gas pressure after the regulator is dangerous for the gas pipeline and devices installed on it. It may decrease somewhat when the relief safety devices operate. Discharge safety devices, unlike safety shut-off devices, do not shut off the gas supply, but only discharge part of it into the atmosphere, reducing the gas pressure in the gas pipeline by increasing its flow rate.
There are hydraulic, lever-load, spring and membrane-spring safety relief devices. Hydraulic relief fuse (hydraulic seal) (Fig. 83). Most common when using low pressure gas. It is simple and reliable in operation.
Membrane-spring relief valve PSK (Fig. 84) Unlike a hydraulic seal, it is smaller in size and can operate at low and medium pressure. Two types of drain valves are produced: PSK-25 and PSK-50, differing from each other only in dimensions and throughput. Gas from the gas pipeline after the regulator enters the PSK membrane. IF the gas pressure from above is greater than the spring pressure from below, then the membrane moves down, the valve opens and the gas is released into the atmosphere. As soon as the gas pressure becomes less than the spring force, the valve closes. The degree of compression of the spring is adjusted with a screw.
Filters (Fig. 85). There are various types filters (mesh type FG, hair, viscine with Raschig rings) which are installed depending on the type of regulator, gas pipeline diameter and gas pressure. Near the RD regulator, a mesh filter of the FG, okaya RDS and RDUK-hair types is installed. At large hydraulic fracturing stations, as well as on high-pressure gas pipelines, viscine filters with Raschig rings are installed.
The most widely used in urban gas supply is the hair filter (see Fig. 85, a). The cassette holder is covered on both sides metal mesh, which traps large particles of mechanical impurities. Finer dust settles inside the cassette on compressed horsehair moistened with viscine oil. The cassette filter resists the gas flow, so a certain pressure difference occurs before and after the filter. To measure it, pressure gauges are installed, according to the readings of which the degree of contamination is judged. An increase in the gas pressure drop in the filter to more than 10 kPa (1000 mm water column) is not allowed, as this may cause hair to be carried away from the cassette. To reduce pressure drops, it is recommended to periodically clean the filter cassettes. The internal cavity of the filter should be wiped with a rag soaked in kerosene. The cassettes are cleaned outside the hydraulic fracturing building.
In Fig. 85, b shows the device of a filter intended for hydraulic fracturing. equipped with RDUK regulator. The filter consists of a welded body with connecting pipes for gas inlet and outlet, a cover and a plug. Inside the case there is a mesh cassette filled with horsehair or nylon thread. A metal sheet is welded inside the housing on the gas inlet side, protecting the mesh from direct ingress of solid particles. Solid particles coming with the gas, hitting the metal sheet, are collected in the lower part of the filter, from where they are periodically removed through the hatch. The remaining solid particles in the gas stream are filtered in a cassette, which can also be read as needed. To clean and rinse the cassette, the top filter cover is removable. To measure the pressure drop that occurs when gas passes through the filter, U-shaped differential pressure gauges are used, connected to special fittings before and after the filter, regardless of the presence of a filter in the hydraulic fracturing equipment set; an additional filter device is installed in front of the rotary meters (see Fig. 85, V).
Control and measuring instruments (instruments). The following instrumentation is installed at gas control points to monitor the operation of equipment and measure gas flow: thermometers for measuring gas temperature, indicating and recording (self-recording) pressure gauges for measuring gas, devices for recording pressure drops on high-speed flow meters (if necessary), consumption metering devices ( consumption) of gas ( gas meters or flow meters).
The gas temperature is measured to introduce corrections when calculating its consumption. If the flow meter is located after the gas pressure regulator, then the thermometer is installed on the section of the gas pipeline between the regulator and gas flow metering devices. Instrumentation should be located directly at the measuring point or on a special instrument panel. If the instrumentation is mounted on the instrument panel, then for measurement they use one device with switches for measuring readings at several points. To measure gas flow rates up to 2000 m3/h at pressures up to 0.1 MPa (I kgf/cmg), rotary meters are used, and for high flow rates and pressures, measuring diaphragms are used. Pulse tubes from the diaphragms are connected to secondary instruments (ring or float differential pressure gauges).
The installation location of meters and flow meters is chosen taking into account the possibility of conveniently taking their readings and carrying out maintenance and repair work without interrupting the gas supply. Instrumentation is connected to gas pipelines steel pipes. To assemble instrument panels, you can use tubes made of non-ferrous metal. At gas pressure up to 0.1 MPa (1 kgf/cm2), rubber tubes up to 1 m long and 8-20 mm in diameter are used. Impulse tubes are connected by welding or threaded couplings. Instrumentation with electric drive, as well as telephone sets must be explosion-proof. otherwise, they are placed in a room isolated from the GRV or outside in a locked box.
Instruments for measuring gas consumption (flow). These devices are installed in accordance with the “Rules for measuring gas and liquid flow rates with standard devices” RD50-213-80. To account for gas consumption, gas meters and flow meters are installed in the GRG, which keep track of gas in cubic meters under operating conditions (pressure and temperature), and payments to consumers are made under standard conditions (pressure 0.102 MPa; 760 mm Hg and temperature 20 ° C). Therefore, the amount of gas indicated by the instruments is reduced to standard conditions. In small, medium-sized hydraulic fracturing facilities, they found wide application volumetric rotary counters type PC. The currently specified counter counts. The meter consists of a housing, two profiled rotors, a box with gears, a gearbox, a counting mechanism and a differential pressure gauge. The gas enters the working chamber through the inlet pipe, where the rotors are located. Under the influence of the pressure of the flowing gas, the rotors begin to rotate. In this case, a closed space filled with gas is formed between one of them and the chamber wall. Rotating, the rotor pushes gas into the gas pipeline going to the consumer. Each rotation of the rotor is transmitted through gearboxes and a gearbox to the counting mechanism. The meters are installed on vertical sections of gas pipelines so that the gas flow is directed through the meter from top to bottom. If necessary, measurements large quantities parallel installation of gas meters is allowed. The PC meter accounting error does not exceed 23%.
The following modifications are available: PC-25; PC-40; RS-100; PC-250; PC-400; RS-600M and RS-1000. The numbers respectively indicate the nominal throughput of the meter in m 3 / h. High-speed flow meters are used to measure the consumption of large quantities of gas. They are installed at large hydraulic fracturing sites and facilities. Flow meters, depending on the adopted measurement method, are divided into those whose operation is based on throttling the gas flow through restricting devices installed on gas pipelines, and flow meters whose operation is based on determining consumption (flow) by the velocity pressure of the gas flow. Flow meters with restriction devices in the form of metal diaphragms (washers) are widely used in the gas industry.
^Gas control point (GRP and GRU).
This is a building on a gas pipeline.
Consumers located in various buildings and premises can be supplied with gas from the gas distribution system.
^ From the GRU, gas can only be supplied to a gas-using unit. Located in the same premises as the GRU.
Hydraulic fracturing and gas distribution units come in medium, low and high pressure, which is determined by the outlet pressure from the hydraulic fracturing and gas distribution unit.
^
Requirements for the GRP premises
The GRP building must comply with the 2nd degree of fire resistance (brick, concrete) with an easily removable roof, weighing no more than 120 kg/sq. m. (so that in the event of an explosion the main structure is preserved).
^ The roof can also be made to be heavily removable, but in this case the area window openings must be at least 0.05 sq. m per 1 cubic meter. volume of hydraulic fracturing room.
The lighting of the GRP building is explosion-proof. If the switches are of a standard design, then it should be outside and no closer than 0.5 m from the doorway.
Ventilation in the room must be at least 3 times greater. The temperature in the room must be determined by the design (clause 3.4.8. PB in GC) depending on the design of the equipment used and instrumentation in accordance with the equipment manufacturer’s passports.
Floors must be of non-sparking material.
The air supply should be carried out through the louvered grilles, and the removal through a deflector installed in the roof. The ends of the mounted deflector should not protrude inside the gas distribution unit, only flush with the ceiling, because the gas is lighter than air and will accumulate at the top.
^ Window openings must be glazed from a single sheet, and on the outside - protected with a fine-mesh mesh (to prevent fragments from flying in the event of an explosion).
Distance from GRP buildings to boiler houses according to SNIP^II-89-80* (clause 3.22) there must be at least 9 m to gas consuming structures. In terms of explosion and fire hazard, the premises of the gas distribution center correspond to category A.
The gas inlet pressure into the boiler room should not exceed 6 kgf/cm 2 .
Gas pressure of 12 kgf/cm is allowed to be supplied to the hydraulic fracturing room 2 .
The GRP building must have the inscription “FLAMMABLE”. The hydraulic fracturing works in automatic mode, therefore front door must be locked.
^
Technological chain of hydraulic fracturing.
The hydraulic fracturing technological chain consists of the main line and the bypass (bypass) line. The bypass is embedded before the high-pressure operating valve (1) and after the low-pressure operating valve (5) on the main line. The bypass is equipped with two valves, between which there is a purge plug and a pressure gauge.
^ On the main hydraulic fracturing production line there is a working valve (1) of high pressure and a working valve (5) on the reduced pressure side.
After the valve (1), a filter (2) is installed, designed to purify the gas from mechanical impurities. It is allowed to take the filter outside the GRP premises to the street from the side of the gas inlet to the GRP.
Pressure gauges (9) and (10) are installed before and after the filter, the difference in readings of which determines the degree of cleanliness of the filter. The gas pressure drop across the filter should not exceed the value set by the manufacturer (clause 3.4.12. Safety precautions in the GC). The pressure gauges on the filter must have the same accuracy class and the same scale, otherwise the difference in readings cannot be determined. The filter must be cleaned once a year.
After the filter, a safety shut-off valve (SSV) is installed along the gas flow. The slam-shut valve is installed in front of the regulator along the gas flow on a high-pressure gas pipeline, and controls the pressure after the regulator (i.e. low).
The SCP is connected to the reduced pressure through the impulse tube.
The SCP cuts off the gas supply to the regulator if the gas pressure behind it increases by no more than 25% (clause 3.4.3. PB in the GC), and if the gas pressure behind the regulator decreases to the value established by the boiler burner passport (minimum value pressure according to the burner data sheet). The SCP is triggered automatically.
After the shut-off valve, a pressure regulator is installed along the gas flow, which is designed to reduce the gas pressure and maintain it at a given level, regardless of gas flow.
After the regulator, a purge plug (15) and a pulse sampling line are mounted. This line is designed to supply a quiet gas pulse (in laminar mode) to the SCP and RDUK to control the gas pressure after the regulator in quiet mode, i.e. without water hammer.
After the regulator, on the side of reduced gas pressure, a safety relief valve (PSV) is installed, which is designed to release gas into the atmosphere if its pressure behind the regulator increases by no more than 15% of the working one.
A low pressure gauge is installed after the regulator.
^
Purge discharge pipelines of hydraulic fracturing.
GRP purge discharge pipelines are designed to release gas into the atmosphere to free the GRP from gas before repair work for relieving excess gas pressure from the PSK, for purging the gas station with gas when displacing air during the initial start-up of the hydraulic fracturing unit and the gas station into operation.
The diameter of the purge pipelines must be at least 20 mm, and equipped only with taps (but not valves) for rapid gas release. Purge pipelines should have a minimum number of turns and bends, and there should be no narrowed sections or dents.
The purge pipeline is installed above the roof of the building by at least 1 meter and its end must be protected from precipitation.
^
Gas filters.
Filters are made of cast iron with a diameter of 50 to 200 mm, steel, welded and mesh.
Cast iron filter . It has a cast iron body, inside of which there is a filter cassette (5). On top of the housing there is a cover (2) with bolts. Flange filter. The flanges of the cast iron filter have threaded holes for connecting pressure gauges.
^ There is an arrow on the filter housing indicating the direction of medium flow, Ru and Du.
Welded steel filter . It is a structure welded from an upper and lower bottom. Upper part It is attached to the body with bolts and acts as a cover. At the bottom of the filter there is a hatch for removing large mechanical impurities; There is a filter cassette inside the housing and a metal sheet plate is installed along the gas flow at the inlet of the housing, designed to protect the filter cassette from destruction when large mechanical objects enter it.
^ The filter has two pipes: inlet and outlet, on the body Ru and Du.
Strainer . It is used in cabinet gas control units or points. It is manufactured in small diameters from 25 to 40mm.
Filter cassettes
All filters are filled with horsehair or other synthetic material, equivalent to horsehair.
Welded steel filter
Strainer
Cleaning the filter.
This work is gas hazardous and is carried out according to work permit by a team of at least 3 workers under the supervision of engineers. Belongs to the first group of gas hazardous work. The filter is cleaned according to a schedule approved by the chief engineer of the enterprise, as necessary, but at least once a year.
^ The pressure drop across the filter is set by the manufacturer.
Before cleaning the filter, the following preparatory work is carried out:
The hydraulic fracturing operation is carried out via a bypass bypass line.
The valves (1) and (5) on the main hydraulic fracturing line are closed.
The valves of the purge pipelines (14) and (15) are opened to discharge gas into the atmosphere. Using the pressure gauges (9) and (10) on the filter, we are convinced that there is no pressure.
After the working valve (1), a plug is installed along the gas flow, and a plug is also installed in front of the working valve (5) (on the side where there is no gas pressure).
The doors of the gas distribution center must be open throughout the entire work, and a mechanic must stand outside, whose duties include monitoring the condition of workers, preventing unauthorized persons and fire. If you work in gas masks, then the mechanic monitors the position of the gas mask hoses.
The filter cover is removed, the filter cassette is removed, placed in a metal bucket and quickly taken outside to avoid ignition of pyrophoric compounds in the hydraulic fracturing room contained in the filter cassette. Pyrophoric compounds in the filter cassette are formed due to the odorant supplied to the gas (C 2 N 5 SN). Pyrophoric compounds are capable of self-ignition upon contact with atmospheric oxygen.
The filter cassette is cleaned outdoors no closer than 5m from the gas fracturing building in places away from flammable substances and materials (clause 3.4.12. Safety precautions in gas storage).
The filter cassette is shaken out, washed with kerosene, then moistened with machine oil, allowed to drain, then inserted into a previously cleaned filter housing.
If necessary, filter material can also be added to the filter cassette. Place a new paronite gasket and put on the lid. Then remove the plugs and make the transition from the bypass to the main line according to the instructions.
^ After starting the gas, wash the connections of the filter housing with the cover to check for gas leakage into the hydraulic fracturing unit.
Safety shut-off valve.
A safety shut-off valve (SSV) is a device that ensures that the gas supply is stopped, in which the speed of bringing the working element to the closed position is no more than 1 second (Appendix 1 PB in the GC).
^ There are two types of PZK:
PKN - low pressure safety shut-off valves;
PKV - high pressure safety shut-off valves;
PKN or PKV - this is determined by the outlet pressure from the hydraulic fracture. These valves differ from each other in the following ways:
The PCV has more powerful springs to configure it to work according to the specified parameters.
PCV has a disk on the top of the membrane, i.e. they also differ in the active area of the membrane.
There is an arrow on the PZV body indicating the direction of gas, Ru, Du. Attached to the top of the lid is a plate with the name PKN or PKV, serial number, and date of manufacture.
Setting the slam-shut valve.
The slam-shut valve consists of the following main components:
Frame.
The head is an intermediate insert.
Lid.
Leverage. The lever system includes a hammer and a crank lever. a lever with a weight and a rocker-lever fixed at one end to the diaphragm rod.
Valve type housing, cast iron. Inside the body there is a seat, the main valve, in which the bypass valve is mounted. The valves are connected to the axle through the fork. A lever with a load is attached to the end of the axle emerging from the housing. At the exit of the axle from the housing there is an oil seal with a grand axle box. The valve has a guide column and a guide rod at the bottom for correct landing valve onto the seat when activated.
An intermediate head is attached to the upper part of the housing, an insert in which there is a blank partition that separates two different pressures in the shut-off valve: at the bottom under the partition - high blood pressure, equal to the inlet pressure in the hydraulic fracturing; and above the partition - low pressure, equal to the pressure after the regulator.
A cover is attached to the head, in which there are two springs: large and small, for adjusting to the specified pressures. The cover contains a rocker arm, an adjusting screw and an adjusting nut.
A membrane is sandwiched between the cover and the head - intermediate insert. Between the membrane and the blind partition of the head, a membrane chamber is formed, which communicates through a fitting and an impulse tube with the outlet gas pressure after the regulator, i.e. the pressure in the membrane chamber is equal to the pressure on the pressure gauge after the regulator and equal to the pressure in front of the gas-using unit (boiler burner). Communication occurs on the principle of communicating vessels. The membrane is connected to the rod at the top. There are two springs on the rod: large and small, designed to adjust the shut-off valve to the specified pressures. In the membrane rod, one end of the rocker arm is rigidly fixed to the axis. The second end of the rocker arm, in normal operating condition, is engaged with the protrusion on the hammer and holds the hammer in vertical position.
The membrane chamber has a threaded hole, closed with a plug, which is intended for the convenience of connecting an impulse tube or checking the shut-off valve for operation according to the specified parameters according to the schedule without increasing the gas pressure to the consumer.
Normal operation of the slam-shut valve and its activation.
In the working position (during normal operation), the hammer is in a vertical position, the engagement of the rocker arm with the protrusion on the hammer is good, the lever with the load is raised and is held in this position by the cranked lever. The slam-shut valve is open and gas flows through it to the regulator.
^ The safety valve does not reduce gas pressure: before and after it the pressure is the same 6 or 12 kgf/cm 2 , i.e. equal to input.
The operation of the shut-off valve when the gas pressure behind the regulator increases to the value at which the shut-off valve should operate, i.e. turn off the gas. This increased pressure flows through the impulse tube into the membrane chamber of the PZK (according to the principle of communicating vessels). At the same time, the membrane bends upward. The diaphragm rod will also move up along with the end of the rocker arm fixed in it.
The second end of the rocker will go down and disengage with the protrusion on the hammer. The hammer will fall on the bell crank, knocking it out of engagement with the lever with the load.
^ The lever, under the action of the load, will go down, rotate the axis on which it is attached and place the valve on the seat, cutting off the gas supply.
When the gas pressure behind the regulator decreases, the reduced pressure will enter the membrane chamber of the shut-off valve, and the membrane will bend down under the force of a small spring. In this case, the large spring sits on a support plate fixed to the protrusions of the cover and does not participate in the work. The membrane will bend down, the rod connected to the membrane and the end of the rocker arm attached to it will go down. In this case, the second end of the rocker will rise up and disengage with the protrusion on the hammer. The hammer will fall on the crank arm and dislodge it from its engagement with the weighted arm. The lever with the weight will move down, turning the axis, and seat the valve on the seat, blocking the gas passage.
Setting the shut-off valve to a given mode.
The settings for the SLC are determined by the project and are specified during commissioning (clause 3.4.4. PB in the GC).
At the beginning, the slam-shut valve is configured to be triggered by reduced gas pressure (but not vice versa), otherwise it cannot be configured.
We turn on the hydraulic fracturing operation, to do this we open the valves, the shut-off valve (raise the lever with the load, secure it in a raised form with a crank lever, and tie the hammer with wire or simply hold it by a mechanic, after all, a team of 3 people!).
Using the regulator at the outlet pressure gauge, we set the low gas pressure at which the shut-off valve should operate, i.e. shut off the gas in the event of an emergency decrease in gas pressure.
Using a screwdriver, turn the adjusting screw for adjusting the small spring to the right or left so that the rocker engages with the protrusion on the hammer just barely (the main thing is that it engages). That's it, it is believed that after this the slam-shut valve is set to the lower limit for operation.
Setting the slam-shut valve to operate at the upper limit.
We hold the hammer in a vertical position or tie it to the lid. Using the regulator at the outlet pressure gauge, we set the pressure at which the shut-off valve should stop the gas supply if it rises to an emergency value.
^ For example: Work = 0.4 kgf/cm 2 to the burner, then we must set the SPV at the upper limit in the range from 15% to 25% of Rrab.;
Then: Rup.=0.4 1,25…0,4 1.15=0.5…0.56 kgf/cm 2 .
Holding the adjusting screw for setting the slam-shut valve to low pressure with a screwdriver, use a wrench to turn the nut, compress or loosen the large spring until the rocker engages with the protrusion on the hammer (barely). That's it, it is believed that after this the slam-shut valve is set to trigger when there is increased pressure. After this adjustment, tighten the fixing screws in the top cover so that vibration does not interfere with the slam-shut adjustment. The setting of the slam-shut valve is duplicated several times (i.e., it is tested for operation).
Malfunctions:
The valve does not fit tightly to the seat. The valve seal may become leaky due to cracks in the rubber, scratches, or a hole in the body seat (then it needs to be ground in).
Gas leaks through the stuffing box at the axle exit from the housing. Relieve the pressure, refill the oil seal (work according to the permit).
The oil seal is tightly clamped. The lever with the load goes down slowly or does not go down at all.
Rupture of the shut-off valve membrane (there will be a leak into the hydraulic fracturing room, since the cover is not airtight).
The springs have lost their elastic properties over time.
Bent levers and rocker arms. The hammer, crank, etc. were also bent during transportation.
Poor rotation of the hammer and crank arm. It is necessary to lubricate the axles with grease.
Gas leaks through micropores in the slam-shut valve housing. Wash with soapy water.
