Ministry of Education and Science of the Samara Region

State budgetary educational institution

secondary vocational education

"Provincial College of Syzran"

Technical profile

Toolkit

TECHNOLOGICAL PIPELINES

PM 01 Operation of technological

equipment.

PM 05 Performing work in the profession

Process plant operator

Sizran.

2015

Methodological manual on topics PM 01 “Operation of technological equipment,

PM 05 Performing work in the profession of Technological Plant OperatorMDK 05.02. Repair of technological equipment.

(name of methodological development)

Brief description of the Methodological manual

This manual presents types of process pipelines, operating rules, maintenance requirements, preparing them for repair and testing. Intended for students of secondary vocational education "GK Syzran" in the specialty 240134.51 Oil and gas refining when training in the professional module PM 01. Operation of technological equipment and PM 05 performance of work in the profession Process Plant Operator.

The methodological manual will allow students to develop knowledge and practical skills in operating equipment at oil refineries.

Compiled by: Pirogova Galina Nikolaevna- special teacher disciplines.

APPROVED AT THE PCC MEETING

Oil and gas processing. Ecology

(name of commission)

Chairman _____________________ V.V. Mokeeva

FULL NAME

Protocol No. __________ dated “____”__________2015

Technical methodologist _______________ L.N. Barabanova

FULL NAME.

"APPROVED"

Deputy Director for Management and Development

Head of technical profile __________________ V.V. Kolosov

Process pipelines

1. Learning objective

The purpose of studying the topic “Technological pipelines” is to teach students the classification, types of technological pipelines, operating rules, maintenance requirements, preparing them for repair and testing.

1.1. Concept, basic terms

Definition of technological pipelines, their classification. Location of pipelines. Pipeline elements. Division of pipeline fittings into: shut-off, control, safety. Types of connecting fittings to pipelines. Structural elements of reinforcement. Operation and repair of process pipelines.

Pipeline- a structure made of pipes, pipeline parts, fittings, tightly connected to each other, intended for transporting gaseous and liquid products.

Technological are the pipelines of industrial enterprises through which raw materials, semi-finished products, finished products, steam, water, fuel, reagents and other materials are transported that ensure the implementation of the technological process and the operation of equipment, waste reagents, gases, various intermediate products obtained or used in the technological process, waste production.

Flange connection- a fixed detachable connection of a pipeline, the tightness of which is ensured by compressing the sealing surfaces directly against each other or through gaskets of a softer material located between them, compressed by fasteners.

Welded connection- a fixed pipeline connection, the tightness of which is ensured using welding.

Retraction- a shaped part of a pipeline that ensures a change in the direction of flow of the transported substance.

Tee- a shaped part of a pipeline for merging or dividing flows of transported substances at an angle of 90 0 C.

Union- a part intended for connecting fittings, instrumentation, etc. to the pipeline.

Transition- a shaped part of a pipeline designed to expand or narrow the flow of a transported substance.

Pipeline section- part of a process pipeline made of one material through which a substance is transported at constant pressure and temperature.

Pipeline accessories- devices installed on pipelines and providing control of the flow of working media by changing the flow area.

Conditional diameter DN- nominal internal diameter of the pipeline, providing the required throughput.

Conditional pressure Ru- the lowest excess pressure at a substance or environmental temperature of 20 0 C, at which long-term operation of fittings and pipeline parts having specified dimensions, justified by strength calculations, with selected materials and their strength characteristics corresponding to this temperature is permissible.

Working pressure Рр- the highest safe excess pressure at which the specified operating mode of fittings and pipeline parts is ensured.

Test pressure Rpr- excess pressure at which hydraulic testing of fittings and pipeline parts for strength and density must be carried out with water at a temperature of not less than +5 0 C and not more than +40 0 C.

2. Contents of the educational element

To train students in the theory and practical performance of work on the operation, inspection, and repair of process pipelines and pipeline fittings.

2.1. General concepts

Pipeline- a device designed for transporting gaseous, liquid and bulk substances.

Depending on the transported medium, the names used are plumbing, steam pipeline, air pipeline, oil pipeline, gas pipeline, oil pipeline, product pipeline, etc.

The design of the pipeline must be reliable, ensure safety during operation and provide for the possibility of its complete emptying, cleaning, flushing, blowing, external and internal inspection and repair, removal of air from it during hydraulic testing and water after it.

The main characteristic of any pipeline is its diameter, which determines its flow area required to transport a given amount of substance under operating operating parameters (pressure, temperature, speed).

All process pipelines with pressure up to 100 kgf/cm 2 inclusive, depending on the hazard class of the transported substance (explosion, fire hazard and harmfulness) are divided into groups (A, B, C) and, depending on the operating parameters of the medium (pressure and temperature) into five categories (I ,II ,III .IV ,V ).

Process pipelines consist of tightly connected straight sections, pipeline parts (bends, transitions, tees, flanges), gaskets and seals, supports and hangers, fasteners (bolts, studs, nuts, washers), shut-off and control valves, control measuring instruments, automation equipment, as well as thermal and anti-corrosion insulation.

Depending on their location at an industrial facility, technological pipelines are divided into intra-shop pipelines, connecting units, machines and devices of technological installations of a workshop, and inter-shop pipelines, connecting technological installations of different workshops. Intrashop pipelines are called piping if they are installed directly within individual devices, pumps, compressors, tanks, etc. and connect them.

Intrashop pipelines have a complex configuration, a large number of parts, fittings and welded joints. For every 100 m of length of such pipelines there are up to 80-120 welded joints. The mass of parts, including fittings, in such pipelines reaches 37% of the total mass of the pipeline.

Inter-shop pipelines, on the contrary, are characterized by fairly straight sections (up to several hundred meters long), a relatively small number of parts, fittings and welds. The total mass of parts in inter-shop pipelines (including fittings) is 5%, and U-shaped compensators are about 7%

Process pipelines are considered cold if they operate in an environment with an operating temperature t p  50 0 C, and hot if the temperature of the working environment is > 50 0 C.

Depending on the conditional pressure of the medium, pipelines are divided into vacuum, operating at an absolute pressure of the medium below 0.1 MPa (abs) or from 0 to 1.5 MPa (g), medium pressure, operating at a pressure of the medium from 1.5 to 10 MPa ( hut). Gravity pipelines are those that operate without excess pressure (“gravity flow”).

Connections in pipelines for transporting liquefied gases must be made mainly by welding. In places where the fittings are installed, flange connections can be used to connect them to the pipeline. They can also be used in pipelines that require periodic disassembly for cleaning or replacement of individual sections. Welding is the most expedient and reliable method of connecting steel pipelines and fittings to the pipeline. It is widely used in pipeline systems for various purposes, but in many cases flange connections are also used, which have their own advantages and disadvantages, just like detachable connections. In pipelines with small nominal diameters, threaded connections are often used.

The location of the pipelines should ensure:

safety and reliability of operation within the regulatory period;

the ability to directly monitor the technical condition;

the ability to perform all types of work on inspection, heat treatment of welds and testing;

insulation and protection of pipelines from corrosion, secondary manifestations of lightning and static electricity;

preventing the formation of ice and other plugs in the pipeline;

eliminating sagging and the formation of stagnant zones.

According to the method of laying pipes, pipelines or their sections are divided into the following:

underground- pipes are laid in a trench underground;

ground- pipes are laid on the ground;

above ground- pipes are laid above the ground on racks, supports or using the pipe itself as a supporting structure;

underwater- constructed at crossings over waterways

obstacles (rivers, lakes, etc.), as well as during development

ke offshore fields.

Questions to consider:

What is the working pressure?

What requirements must the pipeline design meet?

How are process pipelines divided depending on their location at an industrial facility?

Which process pipelines are considered cold?

Which process pipelines are classified as intra-shop pipelines?

What pipes are used to transport fire and explosive media?

Where is it allowed to use flange connections in pipelines for transporting gases?

2.2. Pipeline accessories

Pipe fittings installed on pipelines or equipment are designed to shut off, distribute, regulate, mix or discharge transported products.

According to the nature of the functions they perform, valves are divided into classes: control, safety, shut-off and miscellaneous.

Shut-off valves are designed to shut off the flow of the transported product (taps, valves, gate valves and butterfly valves).

Regulatory– to regulate product parameters by changing its flow rate (control valves and flaps, direct-acting regulators, mixing valves).

Safety– to protect installations, apparatus, tanks and pipelines from unacceptable pressure increases (safety, bypass and check valves, as well as bursting discs).

According to the operating principle, the valves can be autonomous (or direct-acting) and controlled.

Autonomous valves are those whose operating cycle is carried out by the working medium without any extraneous energy sources (direct-acting pressure regulators, condensate traps, gas vents).

Controlled valves are those whose operating cycle is performed according to appropriate commands at moments determined by operating conditions or devices.

Controlled valves, according to the control method, are divided into valves with a manual drive (on-site control), valves driven by a motor, and valves with a remote control (at a distance).

Manually operated valves are controlled by the rotation of a handwheel or handle mounted on a spindle or spindle nut directly or through a gearbox.

The drive fittings are equipped with a drive installed directly on it. The drive can be electric, electromagnetic, with a membrane or with an electric actuator, pneumatic, bellows pneumatic, hydraulic and pneumohydraulic. The valves for remote control are controlled by a drive.

Depending on the design of the connecting pipes, the fittings are divided into flanged, coupling, pin and welded. Coupling and pin-type cast iron fittings are recommended only for pipelines with a nominal diameter of no more than 50 mm, transporting non-flammable neutral media. Coupling and pin-type steel fittings can be used on pipelines for all media with a nominal diameter of no more than 40 mm.

Flanged and welded fittings are allowed for use in all categories of pipelines.

The pipeline fittings used must comply with the requirements of GOST 12.2.063 “Industrial pipeline fittings. General safety requirements." The main types of connecting pipeline fittings to a pipeline are shown in Figure 1.

Pipeline fittings are supplied from manufacturers complete with mating flanges, gaskets and fasteners.

The choice of the type of sealing surface of the flanges for connecting pipelines depends on the transported medium and pressure.

For pipelines transporting substances of groups A and B of technological objects of explosion hazard category I, the use of flange connections with a smooth sealing surface is not allowed, except in cases of using spiral wound gaskets.

a
- flanged (cast flanges with a connecting projection and a flat gasket);

b - flanged (butt-welded steel flanges with a protrusion-recess type seal with a flat gasket);

c - flanged (cast flanges with a tongue-and-groove seal

with flat gasket);

g - flanged (flat welded steel flanges and flat gasket);

d - flanged (cast flanges with a lens gasket);

e - flanged (cast steel flanges with an oval-section gasket);

g - coupling;

z - pin-type.

According to the method of blocking the flow of the medium, the fittings are divided into the following - a gate valve in the form of a disk, plate or wedge (it moves back and forth in its plane, perpendicular to the axis of the medium flow (Fig. 2).

shut-off or regulating body;

frame;

sealing surfaces of the housing.

Gate valves are divided into wedge and parallel based on the type of gate. A wedge gate valve (Fig. 2) has a wedge gate in which the sealing surfaces are located at an angle to each other. They can be with a solid wedge (hard or elastic) and double-disc. A parallel gate valve can be a gate valve (single-disc or leaf) or a double-disc with a wedge thrust.

Questions to consider:

What classes are pipeline fittings divided into based on the nature of the functions they perform?

Purpose of safety valves.

How controlled valves are divided according to methods

management?

Name ways to block the flow of the medium.

2.3. Structural elements of reinforcement

Various reinforcement designs contain parts and assemblies that have a general purpose and the same names (Fig. 8). These elements include the following:

To
body- a part that replaces a piece of pipe with a length equal to the distance between the ends of the attached flanges or pipes for welding to the pipeline. The body together with the lid forms a cavity hermetically isolated from the external environment, inside which the shutter moves;

1 - body; 2 - shutter; 3 - spindle; 4 - sealing gasket; 5 - pressure sleeve; 6 - flywheel; 7 - oil seal; 8 - ring gasket; 9 - top cover; 10 - running nut; 11 - saddle.

gate- moving part of the working body - a part or a structurally combined group of parts intended for hermetically sealing two sections of the pipeline by blocking the passage hole in the flow part of the housing;

To seal the flow tightly, the housing is equipped with a seat equipped with an O-ring. It can be formed by the metal of the body, surfacing of corrosion-resistant steel, brass, or installing an O-ring made of corrosion-resistant steel, brass, nickel alloy, plastic by pressing, threading, caulking and other fastening methods. The shutter in valves is a valve plate (for small sizes it is called a spool), in valves it is a wedge or a disk, or two disks at the same time, in taps it is a plug in the form of a cone, cylinder or ball.

lid- a part used to seal the hole in the body through which the valve is installed. In controlled valves, the cover has a hole for the spindle;

spindle- a part that is a rod, usually having a trapezoidal thread, with the help of which the shutter is controlled. A spindle that does not have a thread is called a rod.

The running nut also has a trapezoidal thread and forms a threaded pair with the spindle to move the shutter and install it in the required extreme or intermediate position (self-locking thread).

stuffing box- a device designed to seal the movable interface of the cover with the spindle;

flywheel- a part (usually casting) that looks like a rim with a hub connected to the rim by spokes. Serves for manual control of valves to transmit torque generated by hands to the spindle or running nut of the valve. A small flywheel is manufactured in the form of a solid disk.

2.4. Supervision of pipelines during operation.

2.4.1. Reliable, trouble-free operation of the pipeline and the safety of its operation must be ensured by constant monitoring of the condition of the pipeline and its parts, timely repairs to the extent determined during inspection and audit, and renewal of all pipeline elements as wear and structural changes in the metal occur.

Fig.4.

2.4.2. By order of the enterprise, in each workshop (at each installation) a person responsible for the safe operation of pipelines must be appointed from among the engineering and technical workers servicing these pipelines.

2.4.3.Technological pipelines, depending on the properties of the transported medium, are divided into three main groups A, B, C, and depending on the operating parameters of the medium (pressure and temperature) into five categories. If the required combination of parameters is not in the table, use the parameter according to which the pipeline is assigned to a higher category (Appendix No. 3).

2.4.4. For process pipelines of categories I, II and III, as well as for pipelines of all categories transporting substances with a corrosion rate of more than 0.5 mm/year, the installation manager must draw up a passport of the established form (Appendix No. 2).

List of documents attached to the passport:

pipeline diagram indicating the nominal diameter, initial and rejection thickness of pipeline elements, installation locations of fittings, flanges, plugs and other parts installed on the pipeline, locations of drainage, purge and drainage devices, welded joints (Appendix No. 3);

act of inspection and rejection of pipelines (Appendix No. 4);

certificate of quality of pipeline repairs.

For the remaining pipelines at each installation, it is necessary to keep an operational log, in which the dates of inspections performed and data on repairs of these pipelines should be recorded (Appendix No. 5).

2.4.5. For each installation, the person responsible for the safe operation of pipelines must draw up a list of critical process pipelines, made in two copies: one is kept by the person responsible for the safe operation of pipelines, the other - in the technical supervision department (Appendix No. 6) .

2.4.6. During the operation of pipelines, one of the main responsibilities of the maintenance personnel is constant and careful monitoring of the condition of the outer surface of pipelines and their parts: welds, flange connections, including fasteners, fittings, insulation, drainage devices, compensators, supporting structures, etc. .P. The results of inspections must be recorded in the logbook at least once per shift.

Fig.5.

2.4.7. Supervision over the correct operation of pipelines is carried out daily by the facility’s engineering and technical workers, periodically by the technical supervision service together with the person responsible for the safe operation of pipelines, at least once every 12 months.

Questions to consider:

How are cables/wires classified depending on the operating parameters and properties of the transported medium?

For which technological cables do you need to obtain standard passports?

For which technological wires is it necessary to create an operational log of the established type?

2.5. Control methods

2.5.1. The main method of monitoring the reliable and safe operation of process pipelines is periodic audits, which are carried out by the technical supervision service together with mechanics and plant managers. The results of the audit serve as the basis for assessing the condition of the pipeline and the possibility of its further operation.

The timing of the inspection of process pipelines is indicated in the projects; in case of their absence, they are established by the OTN, depending on the rate of their corrosion-erosive wear, operating experience, and the results of the previous external inspection and audit. The timing should ensure safe, trouble-free operation of the pipeline in the period between inspections and should not be less than those specified in Appendix 7.

When conducting an audit, special attention should be paid to areas operating in particularly difficult conditions, where the maximum wear of the pipeline is most likely due to corrosion, erosion, vibration and other reasons.

These include areas where the direction of flow changes (elbows, tees, tie-ins, drainage devices, as well as sections of pipelines before and after the fittings) and where accumulation of moisture and substances that cause corrosion is possible (dead-end and temporarily inactive areas).

2.5.2. Conduct an external inspection of the pipeline.

External inspection of pipelines laid in an open way can be carried out without removing the insulation. However, if the condition of the walls or welds of the pipelines is in doubt, at the direction of the technical supervision department employee, partial or complete removal of the insulation must be carried out.

If, during an external inspection, leaks in detachable connections are detected, the pressure in the pipeline must be reduced to atmospheric pressure, the temperature of hot pipelines must be reduced to +60 °C, and the defects must be eliminated in compliance with the necessary safety measures.

If defects are detected, the elimination of which is associated with hot work, the pipeline must be stopped, prepared for repair work in accordance with the instructions of the “Standard Instructions for Organizing Hot Work at Explosive and Explosion-Fire Hazardous Facilities” approved by Rostechnadzor of the Russian Federation, and the defects eliminated.

The person responsible for the safe operation of pipelines is responsible for the timely elimination of defects.

2.5.3. Wall thickness is measured in areas operating in the most difficult conditions (elbows, tees, tap-ins, places where the pipeline narrows, before and after fittings, places where moisture and corrosive products that cause corrosion accumulate - stagnant zones, drainages), as well as in straight sections intra-shop and inter-shop pipelines.

The number of measurement points for each section (element) is determined by the technical supervision department, provided that a reliable audit of pipelines is ensured.

On straight sections of pipelines of technological installations with a length of 20 m or less and inter-shop pipelines with a length of 100 m or less, the wall must be measured in at least 3 places. In all cases, measurements should be made at 3-4 points along the perimeter, and on bends at least at 4-6 points along the convex and concave parts.

It is necessary to ensure the correctness and accuracy of measurements, to exclude the influence of foreign bodies (burrs, coke, corrosion products, etc.) on them. The measurement results are recorded in the pipeline passport.

2.5.4. Hammer tapping method.

Pipelines of categories IV and V are mainly subjected to hammering. Pipelines are tapped along the entire perimeter of the pipe with a hammer weighing 1.0-1.5 kg with a handle at least 400 mm long with a spherical head. The condition of the pipe is determined by the sound or dents that form when tapping. The issue of partial or complete removal of insulation during an audit is decided by the technical supervision service in each specific case, provided that a reliable audit is ensured. If the results of tapping cannot accurately judge the safe operation of the pipeline, it is necessary to measure the wall thickness.

An internal inspection of the pipeline section is carried out using an endoscope, magnifying glass or other means if, as a result of measuring the wall thickness and tapping the pipeline, doubts about its condition arise; In this case, the inner surface must be cleaned of dirt and deposits, and, if necessary, etched. In this case, you should choose an area operated in unfavorable conditions (where corrosion and erosion, water hammer, vibration, changes in flow direction, formation of stagnant zones, etc. are possible). Dismantling of a pipeline section in the presence of detachable connections is carried out by disassembling them, and on an all-welded pipeline this section is cut out. During the inspection, they check for corrosion, cracks, and reduction in the thickness of pipe walls and pipeline parts.

Questions to consider:

When conducting an inspection of electrical cables, which areas need to be given special attention?

How many measurements of the wall thickness of the pipeline must be taken when conducting an inspection on straight sections of pipelines of technological installations 20 m or less in length?

How many measurements of the wall thickness of the cable/wire must be taken when conducting an inspection on straight sections of inter-shop pipelines 100 m or less in length?

How many wall thickness measurements should be taken on bends?

What is the frequency of testing wires for strength and density?

The rejection size for a wire with an outer diameter of 57 mm?

The rejection size for a wire with an outer diameter of 108 mm?

What is the rejection size for a wire with an outer diameter of 219 mm?

What is the rejection size for a wire with an outer diameter of 325 mm?

2.5. Testing pipelines for strength and density.

2.5.1. Process pipelines must be tested for strength and density before putting them into operation, after installation, repairs associated with welding, disassembly, after conservation or downtime for more than one year, when operating parameters change, and also periodically within a period equal to double revision.

After disassembling single flange connections, a pipeline associated with the replacement of gaskets, fittings or a separate element of the pipeline (tee, coil, etc.), it is allowed to test only for density. In this case, the newly installed fittings or pipeline element must first be tested for strength by test pressure.

Pipelines of groups A, B(a), B(b) except for tests for strength and density must be tested for tightness (additional pneumatic tightness test with determination of pressure drop during the test).

Ventilators of individual devices and systems operating without excess pressure and sections of flare lines, as well as short discharge pipelines directly into the atmosphere from safety valves are not tested for strength and tightness.

The pipeline is tested for strength and density simultaneously; it can be hydraulic or pneumatic. Hydraulic testing should preferably be used.

The test is usually carried out before covering the pipeline with thermal or anti-corrosion insulation. It is allowed to test a pipeline with applied insulation, but in this case the installation joints are left open.

The type of test and test pressure are indicated in the design for each pipeline. In the absence of design data, the type of test is chosen by the technical management of the enterprise (pipeline owner).

Before testing, an external inspection of the pipelines is carried out. At the same time, they check the correct installation of the fittings, the ease of opening and closing the locking devices, as well as the removal of all temporary devices and the completion of all welding work and heat treatment (if necessary).

The pipeline should be tested only after it has been fully assembled on permanent supports or hangers, with tie-ins, fittings, bosses, fittings, drainage devices, drain lines and vents installed.

Test pressure should be measured using at least two pressure gauges installed at the beginning and at the end of the pipeline being tested.

Pressure gauges used when testing process pipelines must be checked and sealed.

The pipeline is tested under the direction of the person responsible for the operation of the pipeline, in the presence of a representative of the organization that performed the work. The test results are recorded in the “Quality Certificate” or act (if the “Certificate” is not drawn up), followed by a note in the pipeline passport.

2.5.2. Carrying out hydrotesting.

Hydraulic testing of the pipeline for strength and density is carried out simultaneously.

For hydraulic testing, water is used at a temperature from +5 to +40 ° C or other non-corrosive, non-toxic, non-explosive, non-viscous liquids, such as kerosene, diesel fuel, light oil fractions.

At the same time, in order to avoid large losses of liquids and quickly detect leaks in the pipeline, careful supervision of possible leaks must be ensured.

If testing is necessary at subzero ambient temperatures, liquids should be used whose freezing point is lower than the test temperature listed above.

To check the strength, the pipeline is kept under test pressure for 5 minutes, after which, to test for density, the pressure in it is reduced to that specified in Appendix 8.

To check the density at operating pressure, the pipeline is inspected and the welds are tapped with a hammer weighing 1-1.5 kg. The blows are applied to the pipe next to the seam on both sides.

Defects discovered during inspection (cracks, pores, leaks in detachable joints and seals, etc.) are eliminated only after the pressure in the pipeline has been reduced to atmospheric pressure. After eliminating the detected defects, the test should be repeated. Countering weld seams is prohibited.

When simultaneously hydraulic testing several pipelines for strength, the common load-bearing building structures must be checked.

The results of a hydraulic test for strength and density are considered satisfactory if during the test there is no pressure drop on the pressure gauge and no leaks or fogging appear on the pipeline elements.

Questions to consider:

What types of tests are carried out for wires of groups A, B (a), B (b)?

What pressure is required to test the strength of cables/wires operating at a pressure of more than 2 kg/cm 2?

What pressure is required to test the density of wires/wires operating at a pressure of more than 2 kg/cm 2?

What is the duration of the tightness test for wires of groups A, B (a), B (b)?

What is the permissible pressure drop when conducting a leak test for wires of groups B(a), B(b)?

To repair what categories of cables/wires it is possible to use cable elements that do not have certificates or passports?

For which wires is it possible to use fittings that do not have passports and markings?

2.6. Technical documentation for pipelines

The following technical documentation is maintained for process pipelines:

1. List of critical process pipelines for installation;

2. Pipeline passport;

3. Certificate of periodic external inspection of the pipeline;

4. Certificate of testing process pipelines for strength and density;

5. Certificate for repair and testing of fittings;

6. Operational log of pipelines (maintained for pipelines for which a passport is not prepared)

7. Log of installation and removal of plugs;

8. Documentation for safety valves:

operational passport for the control panel;

technical data sheet for PPK, technical data sheet for a cylindrical compression spring;

set pressure sheet

act of audit and adjustment.

The storage location of technical documentation is determined by the factory instructions depending on the structure of the enterprise.

4. Test questions

How are pipelines classified depending on operating parameters and properties of the transported medium?

For which process pipelines is it necessary to obtain passports of the established form?

For which process pipelines is it necessary to keep an operational log of the established type?

How often should maintenance personnel make entries in the logbook about the results of pipeline inspections?

When conducting a pipeline inspection, which areas need to be given special attention?

How many measurements of pipeline wall thickness must be taken when conducting an inspection of straight sections of pipelines of technological installations with a length of 20 m or less?

How many measurements of pipeline wall thickness must be taken when conducting an inspection on straight sections of inter-shop pipelines 100 m or less in length?

How many wall thickness measurements should be taken on bends?

What is the frequency of testing pipelines for strength and density?

What is the rejection size for a pipeline with an outer diameter of 57 mm?

What is the rejection size for a pipeline with an outer diameter of 108 mm?

What is the rejection size for a pipeline with an outer diameter of 219 mm?

What is the rejection size for a pipeline with an outer diameter of 325 mm?

What types of tests are carried out for pipelines of groups A, B(a), B(b)?

What media are used to conduct g/tests?

At what pressure is it necessary to test the strength of pipelines operating with a pressure of more than 2 kg/cm 2?

At what pressure is it necessary to test the density of pipelines operating with a pressure of more than 2 kg/cm 2?

What is the duration of the leak test for pipelines of groups A, B (a), B (b)?

What is the permissible pressure drop when conducting a leak test for pipelines of groups B(a), B(b)?

To repair pipelines, what categories can it be used to use pipeline elements that do not have certificates or passports?

For which pipelines is it possible to use fittings that do not have passports and markings?

Appendix No. 1.

Group

Name

R slave kgf/cm 2

T slave,

0 C

R slave kgf/cm 2

T slave,

0 C

R slave kgf/cm 2

T slave,

0 C

R slave kgf/cm 2

T slave,

0 C

R slave kgf/cm 2

T slave,

0 C

Substances with toxic effects:

a) extremely and highly hazardous substances of classes I and II (GOST 12.1.007-76) - benzene, acids, hydrogen sulfide, tetraethyl lead, phenol, chlorine

b) moderately hazardous substances of class III - ammonia, methyl alcohol, toluene, solutions of caustic alkalis (more than 10%)

c) freon

Regardless

St.16

Vacuum below 0.8

Above 16

Regardless

From +300 to +700 and below –40

Regardless

-«-

Vacuum from 0.8 to 16

Up to 16

–40 to +300

Regardless

Explosive and fire hazardous substances according to GOST 12.1.004-76

a) flammable gases

b) Flammable liquids (flammable liquids) - acetone, gasoline, kerosene, oil, diesel fuel

c) Flammable liquids (FL) – fuel oil, oils, tar, asphalt, bitumen, oil distillates

Above 25

Vacuum 0.8

Above 25

Vacuum below 0.8

Above 63

Vacuum below 0.03

Regardless

-«-

Above +300 and below –40

Above +300 and below -40

Above +350 and below –40

Above +350 and below –40

Vacuum 0.8

Up to 25

Above 16 to 25

Vacuum below 0.95 to 0.8

Above 25 to 63

Vacuum below 0.08

–40 to +300

Up to 16

-40 to +300

Above +250 to +360

Same

–40 to +120

Above 16 to 25

Vacuum below 0.95 to 0.08

Above +120 to +250

–40 to +120

Up to 16

–40 to +120

Low-flammable (TG) and non-flammable substances (NG) according to GOST 12.1.044

Vacuum below 0.03

St.63

Vacuum below 0.8

St.+350 to +450

St.25 to 63

+250 to +350

St.16

up to 25

St.+120 to +250

Up to 16

–40 to +120

Appendix No. 2

Appendix No. 3

Appendix No. 4

Appendix No. 5

Operational log of non-certified pipelines

Table No. 1

No.

Line name

Audit frequency

Table No. 2

No.

Audit date

Information about pipeline replacement and repair

Signature of the responsible person

Appendix No. 6

Appendix No. 7

Transportable

environment

pipeline

Frequency of inspection at corrosion rate, mm/year

more than 0.5

0,1-0,5

up to 0.1

Group A environments

I and II

at least once a year

at least once every 2 years

at least once every 3 years

Environments of groups B(a), B(b)

I and II

at least once a year

at least once a year

at least once every 2 years

at least once every 3 years

at least once every 3 years at least once every 4 years

Group B(c) environments

I and II

III and IV

at least once a year

at least once a year

at least once every 2 years

at least once every 3 years

at least once every 3 years

at least once every 4 years

Group B environments

I and II

III and IV,V

at least once every 2 years

at least once every 3 years

at least once every 4 years

at least once every 6 years

at least once every 6 years

at least once every 6 years

Appendix No. 8.

Purpose of the pipeline

Pressure, kgf/cm 2

For strength

For density

All process pipelines, except those specified in

paragraphs 2,3,4

Rpr=1.12Rrab * 20/  t

Rrab

Pipelines transporting flammable, toxic and liquefied gases at operating pressure:

• below 0.95 kgf/cm 2

  up to 0.05 kgf/cm 2

  from 0.05 to 0.5 kgf/cm 2

  from 0.5(abs) to 2 kgf/cm 2

not produced

not produced

not produced

Rrab+0.3

R slave but not lower than 0.85

Flare lines

Gravity pipelines

Appendix No. 9.

Appendix No. 10

The volume of control of welded joints by ultrasonic or radiographic methods in% of the total number of welded joints by each welder (but not less than one joint)

Manufacturing conditions

When making a new or repairing an old pipeline

When welding dissimilar steels

When welding pipelines included in blocks of explosion hazard category I

Appendix No. 11

Table 1.

Pipeline classification Ru=< 10 Мпа (100 кг/см²)

General

group

Transportable

substances

Rrab., MPa

(kg/cm ² )

t work.,

°C

Rrab., MPa

(kg/cm ² )

t work.,

°C

Rrab., MPa

(kg/cm ² )

t work.,

°C

Rrab., MPa

(kg/cm ² )

t work.,

°C

Rrab., MPa

(kg/cm ² )

t work.,

°C

Substances with toxic effects

a) extremely and highly hazardous substances of classes 1 and 2

(GOST 12.1.007)

b) moderately dangerous

Class 3 substances

(GOST 12.1.007)

Regardless

Over 2.5

(25)

Regardless

Over +300

and below -40

Vacuum

from 0.08

(0,8)

(abs)

up to 2.5(25)

From –40

before

Explosive and fire hazardous substances GOST 12.0.044.

a) flammable gases (GG),

including liquefied (LPG)

Over 2.5

(25)

Vacuum

below 0.08

(0,8)

(abs)

Over +300

and below -40

Regardless

Vacuum

from 0.08

(0,8)

(abs)

up to 2.5(25)

From –40

before

b) flammable liquids (flammable liquids)

c) flammable liquids (FL)

Over 2.5

(25)

Vacuum

below 0.08

(0,8)

(abs)

Over 6.3

Vacuum

below 0.003

(0,03)

(abs)

Over +300

and below -40

Regardless

Over +350

and below -40

Same

Over 1.6(16) to 2.5(25)

Vacuum

above 0.08

(0,8)

(abs)

Over 2.5

(25) to

6,3 (63)

Vacuum

below 0.08

(0,8)

(abs)

+120 to +300

From –40

up to +300

Over +250

up to +350

Same

Up to 1.6(16)

Over 1.6(16)

up to 2.5(25)

Vacuum

up to 0.08

(0,8)

(abs)

-40 to +120

Over +120

up to +250

–40 to +250

Up to 1.6(16)

–40 to +120

Low-flammability (TG)

and non-flammable substances (NG) according to GOST 12.1.044

Vacuum

below 0.003

(0,03)

(abs)

Over 6.3(63) vacuum below 0.08

(0,8)

(abs)

Over +350

up to +450

Over 2.5(25)

up to 6.3 (63)

From +250

before

Over 1.6(16)

up to 2.5 (25)

Over +120

up to +250

Up to 1.6 (16)

–40 to +120

Notes. 1 . The designation of a group of a specific transported medium includes the designation of the general group of the environment (A, B, C) and the designation of a subgroup (a, b, c), reflecting the hazard class of the transported substance.

2. The designation of the pipeline group in general corresponds to the designation of the group of the transported medium. The designation “pipeline of group A(b)” means a pipeline through which a medium of group A(b) is transported.

A group of pipelines transporting media consisting of various components is installed according to the component,

requiring the pipeline to be assigned to a more responsible group. Moreover, if the mixture contains dangerous

substances Hazard classes 1, 2 and 3, the concentration of one of the components is lethal, the group of the mixture is determined by this

substance.

If the most dangerous component in terms of physical and chemical properties is included in the mixture in an insignificant amount

quantity, the issue of assigning a pipeline to a less responsible group or category is decided by the design

The hazard class of harmful substances should be determined according to GOST 12.1.005 and GOST 12.1.007, the values ​​of fire and explosion hazard indicators of substances - according to the relevant normative and technical documentation or the methods set out in GOST 12.1.044.

For vacuum pipelines, it is not the nominal pressure that must be taken into account, but the absolute operating pressure.

Pipelines transporting substances with an operating temperature equal to or exceeding their auto-ignition temperature or an operating temperature below minus 40 ° C, as well as incompatible with water or air oxygen under normal conditions, should be classified in category 1.

A significant amount of construction of main facilities in the oil refining, metallurgical, and food industries is devoted to the arrangement of process pipelines. They play a critical role in the functioning of strategically important systems. Process pipelines are also used in agricultural complexes, heat supply systems and many other industries.

Basic Concepts

A pipeline is a device designed to transport a variety of substances. It consists of sections of pipes, connecting and shut-off valves, automation and fasteners.

What is the meaning of the concept of “process pipelines?” The definition designates them as supply systems for industrial enterprises through which semi-finished and finished products are transported, as well as substances that support the entire process.

Pipeline location

During the installation process, you must follow these recommendations:

• process pipelines must have a minimum length;
• Sagging and stagnation are unacceptable in the system;
• ensuring free access for technological control;
• the possibility of locating the necessary lifting and transport equipment;
• providing insulation to prevent moisture penetration and retain heat;
• protection of pipelines from possible damage;
• unhindered movement of fire extinguishing equipment and lifting mechanisms.

Slope angles

The operation of process pipelines involves forced stops. For this purpose, slopes are included in the project, which will ensure arbitrary emptying of the pipes. The design of process pipelines provides for the following slope angle depending on the medium being moved (values ​​are given in degrees):

• gaseous medium: in the direction of movement - 0.002, against it - 0.003;
• liquid, easily mobile substances - 0.002;
• acidic and alkaline environment - 0.005;
• substances of high viscosity or quick-hardening - up to 0.02.

The design may not provide for a slope, in which case special measures must be taken to empty the pipelines.

Preparatory work

Installation of process pipelines must first be accompanied by the following actions:

Route markings

This operation consists of transferring the mounting axes of fittings and compensators directly to the place where the process pipelines will be laid. Determining the marking location can be done with the following tools:

• roulette;
• plumb lines;
• level;
• hydraulic level;
• templates;
• squares.

If a large number of process pipelines are laid for a construction structure, the time allocated for marking is significantly reduced through the use of special layouts. They provide a visual representation of the location of pipeline lines in relation to the building structure. After marking, all applied elements are checked against the design, after which they begin fixing the supporting structures.

Installation of supports and fastenings

When arranging the foundation of a building, it must have holes for inserting bolts and fastening supports. They can be made using mechanized equipment. When installing supports, the following recommendations should be taken into account:

1. Process pipelines that have fixed supports described above require the installation of fasteners in close proximity to the devices and fittings. on such supports must be tightly fixed, not allowing movement. The same requirements apply to clamps.
2. Movable supports are mounted with the possibility of unhindered movement of the pipeline in order to freely extend it when the need arises. Thermal insulation must also be maintained during potential movement due to expansion.
3. The process pipeline installer must check all installed supports for horizontal and vertical compliance. Possible deviations are provided for, which cannot exceed the following limits:

• intra-shop pipelines - ± 5 mm;
• external systems - ±10 mm;
• slopes - 0.001 mm.

Plugging into existing systems

This requires special permits, and a process piping installer must be present at the work site to service these lines. The insertion is carried out when a new mounted component is connected to the existing system. Usually, for such cases, the installation of shut-off equipment is provided, but if the existing system does not have one, then they resort to tapping. There are several features here:

1. The existing pipeline must be disconnected and emptied.
2. Pipes through which flammable and explosive atmospheres were transported must be rendered harmless and washed.
3. The welded fitting must pass preliminary tests. The steel grade is also determined according to the documentation.
4. Welding work must be carried out by a highly qualified specialist who has special access to critical structures.
5. Before installation of process pipelines begins, the connecting unit must pass all tests.

Blowing and flushing

The assembled pipeline is subjected to cleaning, the method of which depends on the size of the pipe:

• diameter up to 150 mm - washed with water;
• over 150 mm - blown with air;

The area to be cleaned must be isolated from other pipeline lines with plugs. Flushing with water is carried out until water begins to flow out of the pipe without contamination. Purge is carried out for 10 minutes. These methods are used if the technology does not provide for other cleaning standards. After the work has been completed, you can begin testing, which is performed in two ways: hydraulic and pneumatic.

Hydraulic tests

Before checking, process pipelines are divided into separate conditional sections and the following measures are carried out:

• control by external inspection;
• checking technological documentation;
• installation of air valves, temporary plugs (the use of permanent equipment is prohibited);
• turning off the tested segment;
• connecting the test section to a hydraulic pump.

Thus, the strength and tightness of the pipeline is checked simultaneously. To establish the degree of strength, a special test pressure value is taken into account:

• Steel pipelines operated at operating pressures up to 5 kgf/m². The value of the test parameter is 1.5 of the operating pressure, but not less than 2 kgf/m².
• Steel pipes operating at a pressure exceeding 5 kgf/m². The parameter value for testing will be 1.25 working pressure;
• Cast iron, polyethylene and glass - 2 kgf/m².
• Pipelines made of non-ferrous metals - 1 kgf/m².
• For pipes made of other materials - 1.25 working pressure.

The holding time under the set pressure value will be 5 minutes, only for glass pipelines it increases four times.

Pneumatic tests

For testing, either inert gas is used, which is taken from factory networks or from portable compressors. This option is preferred in cases where hydraulic tests are impossible for a number of reasons: lack of water, very low air temperature, and also when dangerous stresses can arise in the pipeline structure from the weight of water. The value of the maximum test pressure depends on the size of the pipeline:

• for pipe diameters up to 200 mm - 20 kgf/m²;
• 200-500 mm - 12 kgf/m²;
• over 500 mm - 6 kgf/m².

If the pressure limit is different, special test instructions must be developed for such conditions.

Pneumatic Test Requirements

Pneumatic testing is prohibited for above-ground cast iron and glass structures. For all other materials from which process pipelines can be made, there are special testing requirements:

• the pressure in the pipeline increases gradually;
• inspection can be carried out when the pressure reaches 0.6 of the operating value (increasing it during work is unacceptable);
• checking for leaks is carried out by coating with a soap solution; tapping with a hammer is prohibited.

The results of hydraulic and pneumatic tests are considered satisfactory if during the test there was no pressure drop on the pressure gauge.

Transfer of pipelines into operation

At all stages of installation, appropriate documents are drawn up that record the types of work, approvals, tests, etc. They are transferred at the stage of pipeline commissioning as accompanying documentation, they include:

• certificates of delivery of supporting structures;
• certificates for welding materials;
• protocol for internal pipeline cleaning;
• certificates for checking the quality of welded joints;
• conclusion on tests of shut-off valves;
• acts and density;
• a list of welders who performed the connections and documents confirming their qualifications;
• pipeline diagrams.

Technological pipelines are put into operation along with industrial installations, buildings and structures. Only inter-shop systems can be rented separately.

Periodic control should include the following operations:

1. Checking technical condition during external inspection and non-destructive methods.
2. Checking areas subject to vibration with special devices that determine its frequency and amplitude.
3. Troubleshooting problems that were identified during previous inspections.

Equally important is the safe operation of process pipelines, which is ensured by compliance with all established rules.

The monthly system health check should cover the following:

• flange connections;
• welds;
• insulation and coating;
• drainage systems,
• support mounts.

If leaks are detected, for safety reasons the operating pressure must be reduced to atmospheric pressure, and the temperature of the heating lines must be lowered to 60ºC to carry out the necessary troubleshooting measures. The results of the inspection must be recorded in special journals.

Audit

This is used to determine the condition and operational capabilities of pipeline lines. It is advisable to carry out the inspection in areas where the operation of process pipelines is carried out in particularly difficult conditions. The latter include vibrations and increased corrosion.

Pipeline inspection includes the following operations:

1. Checking the thickness of the structure using non-destructive methods.
2. Measuring areas subject to creep.
3. Inspection of welded joints that are in doubt.
4. Examination
5. Condition of support fastenings.

The first audit control should be carried out after a quarter of the period specified in the regulatory documents, but no later than 5 years after the launch of the facility. As a result of timely completion of all inspections, safe operation of process pipelines will be ensured.

Surgut

Purpose and arrangement of process pipelines

Process pipelines– these are pipelines intended for transporting initial, intermediate and final products at an absolute pressure from 0.001 MPa (0.01 kgf/cm 2) to 100 MPa incl. (1000 kgf/cm 2), as well as pipelines for supplying coolants, lubricants and other substances necessary for the operation of the equipment.

Process pipelines operate in a variety of conditions, are exposed to significant pressures and high temperatures, are subject to corrosion and undergo periodic cooling and heating. Their design is becoming more and more complex due to an increase in the operating parameters of the transported product and an increase in pipeline diameters and stricter requirements for the reliability of operated systems.

The costs of construction and installation of pipelines can reach 30% of the cost of the entire facility. In connection with this matter, the paramount importance of specialized design, construction and operating organizations is the technical improvement and re-equipment of technological schemes based on the introduction of the latest scientific achievements and the use of advanced technology. Saving material resources and reducing losses of the pumped product depend on the correct choice of structures, high-quality manufacturing of elements and organization of construction.

Pipeline is a structure consisting of hermetically connected pipes, pipeline parts, shut-off and control equipment, instrumentation, automation equipment, supports and hangers, fasteners, gaskets, materials and parts of thermal and anti-corrosion insulation and intended for transportation of raw materials, intermediate and final products.

Technological pipelines include pipelines located within the on-site facility through which various substances are transported, including raw materials, semi-finished products, intermediate and final products, and production waste necessary for conducting the technological process or operating equipment.

The conditions for the manufacture and installation of process pipelines are determined by: a long branched network and differences in the configuration of the process equipment piping; the variety of materials used, types of pipes, their diameters and wall thicknesses; the nature and degree of aggressiveness of the transported substances and the environment; differences in laying methods /in trenches, without trenches, channels, tunnels, on racks, two- and multi-tiered overpasses on technological equipment, as well as at different heights and often in conditions inconvenient for work/; the number of detachable and permanent connections, pipeline parts, fittings, compensators, instrumentation and supporting structures.

In order to install 1 ton of steel process pipelines, in addition to pipes, it is necessary to consume, on average, various parts and fittings in an amount of up to 22% of its mass.

The main characteristic of a pipeline is the internal diameter, which determines its flow area required to pass a given amount of substance under operating operating parameters /pressure, temperature, speed/. When constructing pipelines, to reduce the number of types and standard sizes of connecting parts and fittings included in pipelines, a single unified series of nominal passages is used.

Conditional diameter DN - nominal internal diameter of the connected pipeline /mm/. A pipe with the same outer diameter can have different nominal inner diameters. For fittings and connecting parts of process pipelines, the following series of nominal diameters are most often used /ST SEV 254-76/, mm: 10, 15, 20, 25, 32, 40, 50, 65, 80, 100, 125, 150, 200, 250, 300, 350, 400, 500. Pipe days, this series is recommended, and the DN for them is established in the project, standards or technical documentation.

When choosing a pipe for a pipeline, the nominal bore is understood to mean its calculated rounded internal diameter. For example, for pipes with an outer diameter of 219 mm and a wall thickness of 6 and 16 mm, the inner diameter of which is respectively 207 and 187 mm, in both cases the closest of the unified series of DN is taken, i.e. 200 mm.

The mechanical strength of pipes, connecting parts and fittings decreases at certain temperature ranges of the substance transported through the pipeline or the environment. The concept of “conditional pressure” was introduced to take into account changes in the strength of connecting parts and pipeline fittings under the influence of excess pressure and temperature of the transported substance or the environment.

Conditional pressure Ru is the highest excess pressure at a substance or ambient temperature of 20°C, which ensures long-term operation of fittings and pipeline parts having specified dimensions, justified by strength calculations for the selected materials and their strength characteristics corresponding to a temperature of 20°C. For example, for fittings and pipeline parts made of steel 20, operating at an excess pressure of 4 MPa and transporting a substance at a temperature of 20 ° C, the conditional pressure Ru = 4 MPa, at a temperature of 350 ° C Ru = 6.3 MPa.

State Committee of the Russian Federation
on architecture and construction issues
(Gosstroy of Russia)

COLLECTIONS OF RESOURCE ESTIMATED STANDARDS
FOR EQUIPMENT INSTALLATION

Collection 12

TECHNOLOGICAL PIPELINES

ReleaseI

Put into effect
letter from Gosstroy of Russia
dated May 5, 1994 No. VB-12-69

Moscow 1994

This collection was developed by AOPI Neftespetsstroyproekt, reviewed by the Central Research Institute of Economics and Construction Management (TsNIIEUS) and the Main Directorate of Pricing, Estimate Norms and Consumption of Construction Materials of the State Construction Committee of Russia.

TECHNICAL PART

1. This collection contains resource estimate standards (RSN) for the installation of process pipelines and general-purpose pipeline fittings during the construction of new, expansion, reconstruction and technical re-equipment of existing industrial enterprises.

2. Process pipelines include pipelines intended for transportation within an industrial enterprise or group of these enterprises of raw materials, semi-finished products, finished products, auxiliary materials that ensure the conduct of the technological process and operation of equipment (steam, water, air, gases, refrigerants, fuel oil, lubricants , emulsions, etc.), industrial waste from aggressive wastewater, as well as return water supply pipelines.

3. Process pipelines do not include pipelines for fire and drinking water supply, heating, sewerage of non-aggressive wastewater and storm sewerage.

4. With a combined water supply (fire-fighting, industrial and drinking), as well as with the combined use of pipelines (if they transport gas, water, steam, etc.) intended for technological purposes and domestic needs, only areas for connecting devices and machines to the lines of combined and combined pipelines.

5. When determining the length of pipelines, their length along the entire route is taken into account, including the expanded length of U-shaped expansion joints and pipeline fittings, with the exception of the construction length of fittings, lens and stuffing box expansion joints.

The average weight of 1 m of pipelines, assemblies and sections of pipelines is given in line 5 of the regulatory tables (the average weight of 1 m of pipelines takes into account the weight of brackets, supports and hangers) and provides for the average pipe wall thicknesses adopted during the development of the collection of 12 prices for equipment installation (RMO-91 ), SNiP 4.06-91. The average values ​​of pipe wall thicknesses are given in the table below.

	Wall thickness, mm
Outer diameter,	Carbon steel and high quality		Alloy and high alloy steel
mm	Conditional pressure, no more, MPA
1020
1220
1420

6. The RSN takes into account the costs of performing a full range of installation work, determined on the basis of the relevant technical conditions and instructions for the installation of process pipelines, including the costs of:

horizontal movement of pipes, fittings and other materials from the on-site warehouse to the installation site at a distance of up to 1000 m;

hydraulic testing of pipelines.

7. The standards provide for work from the floor and inventory scaffolds with a height of up to 3 m. When working from cradles and ladders, as well as on inventory scaffolds with a height of over 3 m, a coefficient of up to 1.3 should be applied to the labor costs of workers and operators and the time of use of machines and mechanisms .

8. The standards provide for installation work to be performed using self-propelled cranes. When performing work with the help of overhead cranes, a correction factor of 0.76 should be applied to the labor costs of workers and operators and the time of use of machines and mechanisms, and with the help of electric winches or manually - 1.15.

When performing work using electric winches, it is necessary to add to the standards of this collection the standards for installation and removal of electric winches according to the collection 37 of the RSN "General Purpose Equipment".

9. The consumption of auxiliary materials given in the RSN is determined according to production standards for the consumption of materials for installation and special construction work. The need for basic materials (pipes, assemblies, sections, parts, etc.) during pipeline installation should be determined from the technical documentation. In the absence of technical documentation, it is recommended to determine the consumption of basic materials using the calculation method set out in Appendix 1 to this collection.

10. The following works are not taken into account in the RSN:

for departments 1 and 2 - production of pipeline parts; equipment, installation, removal of rigging necessary for installation work; construction work related to installation (punching and sealing holes, etc., with the exception of the installation and dismantling of scaffolding);

for departments 1, 2 and 5 - priming and painting of pipes, preliminary and concomitant heating of welded joints, heat treatment of welded joints of pipelines, pickling of pipes with chemical reagents and other special treatments;

testing of welds by gamma fluoroscopy and other methods (ultrasound, etc.).

11. Average level of work on installation of process pipelines - 4.

12. In the normative tables of this collection there is no link to the positions of collection 12 RMO-91 (SNiP 4.06-91) due to differences in the construction of these collections.

13. The name “trailer”, presented as part of machines and mechanisms, should be understood as a set consisting of a tractor and a semi-trailer.

14. Water consumption is not shown in the standard tables and is determined according to the data presented in Appendix 2 to this collection.

15. In the RSN, the level of labor costs of workers and drivers, the time of use of machines and mechanisms is determined on the basis of ENiR and VNiR, put into effect on January 1, 1987. To move from the calculated level of costs to a level that takes into account the real production and technological conditions of the work, It is recommended to apply a coefficient of up to 1.6 to labor costs and time of use of machines.

“TECHNOLOGICAL PIPELINES AND PIPELINE FITTINGS Textbook INTRODUCTION When you enter a chemical plant, the first thing that catches your eye is the pipeline network. Let's see..."

-- [ Page 1 ] --

V.V. FILIPOV

PROCESS PIPELINES AND

PIPELINE ACCESSORIES

Tutorial

INTRODUCTION

When you enter a chemical plant, the first thing that catches your eye is the network of pipelines. Let's look at the picture. Is not

amazing? A web of many pipes of different diameters is clearly visible. The plant consists of production facilities, production facilities - of technological installations, installations - of apparatus. And they are all connected to each other in a single chain using pipelines. Pipelines account for up to 25% of the cost of all equipment. And in the total volume of installation work, the cost of installing pipelines reaches 65%.

In the seemingly chaotic interweaving of many pipes of various diameters, in fact, a strict pattern, verified by calculations, reigns. After all, first the specialists calculated the diameter of each pipeline, selected the grade of steel, and found the thickness of the thermal insulation. Then other specialists laid out each pipe first on paper. And only then did the installers connect the devices with pipelines and build a plant.

General view of modern production

For each pipe the following were calculated and selected:

· diameter, which is determined by the flow rate passing through the pipe;

· wall thickness, which depends on the pressure of the transported medium;

· steel grade, which is determined by the corrosive activity of the substance;

· thickness of thermal insulation, which reduces heat loss to the environment.

All industrial facilities, including pipelines, must comply with the requirements of the Federal Service for Environmental, Technological and Nuclear Supervision (FSETAN), formerly Gosgortekhnadzor.

The tasks of the Federal Service for Environmental, Technological and Nuclear Supervision include:

· organization and implementation on the territory of Russia of state regulation of industrial safety and state supervision for the safe conduct of work, design and safe operation of equipment;

· organization and implementation of state supervision over compliance with the legislation of the Russian Federation on the safe conduct of work;

· development and implementation of measures to prevent accidents and industrial injuries;

· work on the design, manufacture and safe operation of equipment, as well as the protection of subsoil and processing of mineral raw materials;

· implementation of licensing of certain types of activities associated with increased danger of industrial production (facilities) and work;

· participation in the development and control over the implementation of scientific and technical programs to ensure the safety of industrial production, personnel and the population;

· generalization of the practice of applying Russian legislation in the field of safe work and development of proposals for its improvement.

1. TECHNOLOGICAL PIPELINES

1.1. GENERAL CONCEPTS AND DEFINITIONS A pipeline is a structure made of pipes, pipeline parts and fittings tightly connected to each other, intended for the transportation of gaseous and liquid products.

The process pipelines include:

· straight sections (lines);

· shaped parts (bends, reducers, tees, plugs);

· supports and suspensions;

· fasteners (bolts, studs, nuts, washers);

· shut-off and control valves;

· instrumentation and automation equipment;

· thermal and anti-corrosion insulation.

Depending on the transported medium, the names used are: water supply, steam pipeline, air pipeline, oil pipeline, gas pipeline, oil pipeline, product pipeline, etc.

For the geometric characteristics of pipes, the following dimensions are used:

· nominal internal diameter (bore) Dу;

· outer diameter Dн;

· wall thickness;

· length l.

The main characteristic of any pipeline is its diameter, which determines its flow area. The size of the flow area determines the flow rate at its operating parameters (pressure, temperature, speed).

Nominal diameter Dу is the nominal internal diameter of the connected pipeline (mm). A pipe with the same outer diameter can have different nominal inner diameters.

In the oil refining and petrochemical industries, pipes with a nominal internal diameter of 251400 mm, a wall thickness of 216 mm and a length of 412 m are usually used.

For each outer diameter of the pipe, depending on the pressure of the pumped medium, several wall thicknesses are provided.

Consequently, a pipe with a specific outer diameter can have different inner diameters. The internal diameter determines the cross-section of the pipeline required to pass a given amount of substance at operating operating parameters (pressure, temperature, speed).

In the Russian Federation there is a State Committee for Standardization and Metrology, which develops state standards (GOSTs) for all products manufactured in the country. The word “standard” comes from the English word “stadart”, which means “norm, sample”.

In addition to the state standard, industry standards (OSTs) are used in industry.

To reduce the number of types and standard sizes of connecting parts and fittings included in pipelines, a single unified series of nominal diameters Dy is used. For process pipelines, the most commonly used nominal diameters, mm: 10, 15, 20, 25, 32, 40, 50, 65, 80, 100, 125, 150, 200, 250, 300, 350, 400, 500, 600, 800 , 1000, 1200, 1400, 1600. This series of nominal diameters was introduced to limit the number of pipelines used in the design and construction and, as a consequence, reduce the number of standard sizes of connecting parts, fittings, and pipes included in their composition.

When choosing a pipe for a pipeline, the nominal diameter (bore) is understood as its calculated rounded internal diameter. For example, for pipes with an outer diameter of 219 mm and a wall thickness of 6 and 16 mm, the inner diameter of which is respectively 207 and 187 mm, in both cases the nearest nominal pipe diameter is taken, i.e. Dу = 200 mm.

To select the wall thickness (outer diameter of the pipe) and the type of steel that will ensure the mechanical strength of the pipeline at given operating parameters of the environment, the concept of “conditional pressure” is introduced.

Conditional pressure Ru is the highest excess operating pressure (at a medium temperature of 20 °C) at which long-term operation of the pipeline is ensured. To reduce the number of standard sizes of fittings and pipeline parts, GOST established a unified range of conditional pressures (MPa): 0.1; 0.16; 0.25; 0.4; 0.63;

1,0; 1,6; 2,5; 4,0; 6,3; 10; 12,5; 16; 20; 25; 32; 40; 50; 63; 80; 100; 160;

250. For example, if it is intended to transport a flow with a pressure of 2 MPa, then it is necessary to select a pipe designed for a nominal pressure of 2.5 MPa.

Working pressure Pwork is the highest excess pressure at which the specified operating mode of fittings and pipeline parts is ensured.

Test pressure Ppr is the excess pressure at which hydraulic testing of fittings and pipeline parts must be carried out for strength and tightness with water at a temperature of not less than 5 and not more than 70 ° C.

The relationship between conditional, test and working pressures for fittings and connecting parts of pipelines, taking into account the temperature of the working environment, is established by GOST 356-80.

The use of a limited number of pipe sizes simplifies the design of pipelines, ensures a reduction in standard sizes of components (connecting parts, fittings, etc.), facilitates the organization of their mass production, and also simplifies the supply of pipes and products to construction, repair and production organizations.

Pipelines must be reliable in operation, since a malfunction in any part of the pipeline can lead to an accident and a complete shutdown of production or an entire industrial facility, as well as environmental pollution.

Depending on their location at an industrial facility, technological pipelines are divided into intra-shop pipelines, connecting units, machines and devices of technological installations of a workshop, and inter-shop pipelines, connecting technological installations of different workshops.

Intrashop pipelines are called piping if they are installed directly within individual devices, pumps, compressors, tanks, etc. and connect them.

Intrashop pipelines have a complex configuration, a large number of parts, fittings and welded joints. For every 100 m of length of such pipelines there are up to 80,120 welded joints. The mass of parts and fittings in such pipelines reaches 37% of the total mass of the pipeline.

Inter-shop pipelines, on the contrary, are characterized by fairly straight sections (up to several hundred meters long), a relatively small number of parts, fittings and welds.

The total mass of parts and fittings in inter-shop pipelines is 5%. But it is necessary to include U-shaped temperature compensators in the intershop pipelines, which account for about 7% of the mass (U-shaped compensators are described in detail on page 28).

Process pipelines are considered cold if they operate in an environment with a working temperature tp 50 °C, and hot if the temperature of the operating environment is more than 50 °C.

Depending on the conditional pressure of the medium, pipelines are divided into vacuum, operating at an absolute pressure of the medium below 0.1 MPa, medium pressure, operating at an excess pressure of the medium from 1.5 to 10 MPa, and high pressure, when the excess pressure of the working medium is in the range of 10 up to 100 MPa.

In addition, there are also so-called non-pressure pipelines, in which the medium moves by gravity.

All connections used in industry can be divided into permanent and detachable (see section 1.2). In pipelines, as a rule, permanent connections are used - welding. Welding is the most expedient and reliable method of connecting steel pipes. It is widely used in pipeline systems for various purposes. But in many cases it is more advisable to use detachable (flange and threaded) connections, which have their own advantages and disadvantages. Thus, in places where valves are installed, in order to connect them to the pipeline, it is customary to use flange connections. They can also be used in pipelines that require periodic disassembly for cleaning or replacement of individual sections. And in pipelines with small nominal diameters, threaded connections are often used.

According to the method of laying pipes, pipelines or their sections are divided into:

· underground – pipes are laid in a trench underground;

· ground – pipes are laid on the ground;

· above-ground - pipes are laid above the ground on racks, supports, or using the pipe itself as a supporting structure;

· underwater – constructed at crossings through water obstacles (rivers, lakes, etc.), as well as during the development of offshore fields.

A detailed classification of process pipelines is given in the table.

Depending on the hazard class of the transported substance, process pipelines are divided into three groups A, B and C.

Group A includes pipelines for the transport of extremely and highly dangerous substances of hazard classes I and II (benzene, dichloroethane, methyl chloride, etc.).

Group B includes pipelines for the transport of moderately hazardous substances of hazard class III (liquid ammonia, vinyl acetate, xylene, methanol, furfural, etc.). Group B includes pipelines intended for pumping explosive and fire hazardous substances (flammable liquefied gases, flammable liquids, flammable liquids).

In addition to dividing into groups, the division of process pipelines into five categories I, II, III, IV, V is also used, depending on the pressure and temperature of the pumped medium. In order to determine the group and category of the pipeline, it is necessary to use the “Rules for the design and safe operation of process pipelines”.

Classification of process pipelines

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The location of the pipelines must ensure:

· safety and reliability of operation within the regulatory period;

· possibility of direct observation of technical condition;

· the ability to perform all types of work on inspection, heat treatment of welds and testing;

· insulation and protection of pipelines from corrosion, secondary manifestations of lightning and static electricity;

· preventing the formation of ice and other plugs in the pipeline;

· eliminating sagging and the formation of stagnant zones.

1.2. TYPES OF PIPE CONNECTIONS In any industry, including chemical and oil refining, various connections of parts, assemblies, machines, instruments, apparatus and equipment are widely used.

As already noted, connections are detachable and permanent. Permanent connections include those made by welding or soldering, while detachable connections include flanged and threaded ones (fittings, couplings, and some others).

The choice of connection depends on the material of the parts to be connected, pressure, temperature and physical and chemical properties of the transported substance (aggressiveness, toxicity, ability to solidify or form sediment), operating conditions (tightness, the need for frequent disassembly, fire and explosion hazards of production).

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The most widely used method for producing permanent connections of process pipelines is by electric arc welding, which provides high strength, reliability and density of the connections. During the construction and repair of pipelines, various types of permanent welded joints of pipes and pipeline parts are used, some of which are shown in Fig. 1.1.

Among detachable connections, flange connections come first (Fig. 1.2). They consist of flanges 3 and 4, gaskets (obturation) 5, connecting bolts 2 (or studs) with nuts.

The tightness of the connection is achieved due to ring gaskets made of elastic material installed between the end surfaces of the flanges.

Rice. 1.2. Pipeline flange connection:

1.6 – pipeline sections to be connected; 2 – bolt (stud) with nut; 3,4 – flanges; 5 – gasket (obturation) Union connections1 (Fig. 1.3) are used in pipelines intended for the transport of thick and liquid lubricants, high-pressure communications, on water and gas lines, as well as for connecting threaded pipeline fittings and instrumentation and automation . On the thread there is also a fitting (German: Stutzen - short-barreled gun, sawn-off shotgun) - a part intended for connecting fittings or instrumentation to the pipeline.

connect pipelines made of cast iron and steel-lined pipes.

Union connections for flexible pipelines (hoses) are sometimes called durite connections.

The detachable type also includes a coupling connection (Fig. 1.4), which is used for the installation of water and gas pressure pipes. At one end of the pipe, an elongated thread (squeeze) is cut or welded, onto which coupling 2 and locknut 3 can completely fit. At the end of the other pipe, a short thread with a length equal to approximately half the length of the coupling is cut. The pipes are connected by screwing the coupling from the bend onto the short thread until it stops. To ensure the necessary seal in the thread, use a tape made of polymeric materials, tow or flax on lead or white lead, pressing them with a lock nut.

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Gaskets. To seal flange connections of pipelines and fittings, gaskets made of special gasket materials are used. They must have sufficient elasticity and strength to withstand internal pressure and thermal expansion of the pipeline, chemical resistance in aggressive environments, and heat resistance. The choice of type and material of gaskets depends on the specific operating conditions of the pipeline - temperature, pressure and degree of aggressiveness of the environment. The shape and dimensions of the gaskets are determined by the configuration of the sealed joints (Fig. 1.5).

Both non-metallic materials and metals are used for the manufacture of gaskets. Metal gaskets are used for critical objects and severe operating conditions of fittings (high temperature, high pressure, etc.), but they require greater tightening forces than soft gaskets.

Rice. 1.4. Coupling connection:

1-pipe section with long thread; 2-clutch; 3-lock nut; 4-pipe short thread Non-metallic materials. Rubber is the most suitable material for sealing detachable joints. It is elastic, requires little effort to tighten the seals, and is practically impenetrable to liquids and gases. Rubber is used at temperatures up to +50 °C, and heat-resistant rubber – up to +140 °C. Based on hardness, rubber is divided into soft, medium-hard and hard.

There are five types of rubber: oil- and petrol-resistant (grades A, B and C, depending on the degree of resistance), acid-alkali-resistant, heat-resistant and food-grade.

Gaskets made of cellulose spacer board are used in fittings for low pressure steam and water at an operating temperature of less than 120 ° C and a working pressure of up to 0.6 MPa, for oil with a temperature of less than 80 ° C and a working pressure of up to

0.4 MPa, as well as in other cases.

Cellulose cardboard is not suitable for high temperatures as it becomes carbonized.

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Fiber sheet (FLAC) is paper or cellulose that has been treated with zinc and then calendered (pressed). Fiber is used for gaskets in fittings at temperatures up to 100 °C. It is used when working on kerosene, gasoline, lubricating oil, oxygen and carbon dioxide.

Asbestos is used as a cushioning material in fittings at elevated and high temperatures. A material of mineral origin, used in technology after processing in the form of sheet cardboard or cord. At a temperature of 500 °C, the strength of asbestos decreases by 33%, and at 600 °C - by 77%.

Asbestos is quite resistant to alkalis; anthophyllite asbestos is most resistant to acids.

Unimpregnated asbestos cardboard has a loose structure, low strength, but high heat resistance; it is used for fittings operating at temperatures up to 600 ° C, valves for hot blast, generator and flue gases and for other fittings that do not operate on liquid. Asbestos cardboard impregnated with natural drying oil can be used for petroleum products at pressures up to 0.6 MPa and temperatures up to 180 ° C, however, replacing it when changing gaskets or repairing fittings is difficult, since it sticks to metal surfaces. To seal the flanges of gas valves, an asbestos cord is also used, which is laid spirally on the surface of the flange, previously lubricated with technical petroleum jelly.

Sheet paronite is made from a mixture of asbestos fibers (60-70%), rubber (12-15%), mineral fillers (15-18%) and sulfur (1.5-2.0%) by vulcanization and rolling under high pressure. The heat resistance of paronite depends on the amount of rubber in it. Paronite is a universal gasket material and is used in fittings for saturated and superheated steam, hot gases and air, alkali solutions and weak acid solutions, ammonia, oils and petroleum products at temperatures up to 450 °C. To improve the density and increase the resistance to expansion of the gasket by the medium, two or three narrow grooves of a triangular cross-section are usually created on the sealing surfaces of the connection, in which the paronite is pressed under the action of the tightening force. Such grooves are also made when using other non-metallic gaskets. Paronite sheets are manufactured up to 7.5 mm thick. It is advisable to use a gasket that is as thin as possible, but its thickness should be sufficient for compaction for a given roughness of the treated surfaces and compaction area.

Sheet paronite is produced in four grades: PON (general purpose paronite), PMB (oil and petrol resistant paronite), PA (mesh reinforced paronite), PE (electrolysis paronite). The first three brands are used for sealing joints of the following types: “smooth” with a working fluid pressure of no more than 40 kgf/cm2; "tenon and groove"; "protrusion into depression".

Paronite sheets have dimensions from 0.30.4 to 1.53.0 m, sheet thickness from 0.4 to 7.5 mm. The conditions for using paronite for various environments and the maximum operating parameters of the environment are given in GOST.

Plastics for gaskets are used in fittings operating at low temperatures. Polyvinyl chloride plastic compound is most similar in elasticity to rubber; it is used for fittings in chemical production at a relatively low temperature range (from -15 to + 40 ° C). Polyethylene can be used as gaskets at ambient temperatures from – 60 to + °C. Fluoroplastic-4 and fluoroplastic sealing material (FUM), produced in the form of cords of various profiles and sections, are used for temperatures from –195 to +200 °C. Vinyl plastic is used to a limited extent as a cushioning material.

Metal materials. Metal gaskets are made in the form of flat rings of rectangular cross-section from sheet material or in the form of shaped rings from pipes or forgings. In addition, combined gaskets are produced, consisting of a soft core (asbestos or paronite), lined with sheet material made of aluminum, low-carbon steel or corrosion-resistant steel X18N9 or X18N10T.

Advantages of metal gaskets: sufficient density at high pressures and ambient temperatures, the coefficient of linear expansion is close to the coefficient of linear expansion of the material of the flange and studs or bolts, they can be used several times after repair. The disadvantages include: the need to create large forces to ensure the tightness of the connection, relatively low elastic properties.

2. PIPING DETAILS

In the manufacture and installation of steel process pipelines, welded connecting parts are used for the following purposes:

· bends to change the direction of flow of the transported product;

· transitions for changing the diameter of the pipeline;

· tees, tee connections, crosses and saddles for arranging branches;

· plugs for closing the free ends of pipelines.

2.1. BRANCHES ON PIPELINES A bend is a shaped part of a pipeline designed to change the direction of flow.

The main geometric characteristics of bends are:

· the angle at which the flow turns; this angle can take values ​​20, 30, 45, 60, 90, 110, 130, 150, 180 °;

· the ratio of the turning radius R to the internal diameter of the pipeline Dy, which is also normalized and can take values ​​1, 1.5, 4, 6, 15, 30.

Bends (Fig. 2.1) according to their design and manufacturing method are divided into:

· seamless steeply curved or bent;

· Steeply curved stamp-welded;

· welded (sectional).

Seamless steeply curved bends (see Fig. 2.1, a) have a small bending radius R=(1.01.5) Dy, the same wall thickness on the convex and concave generatrices and small dimensions. Their use ensures a compact arrangement of pipelines and equipment and, as a result, saving production space.

Such bends are made from seamless pipes without straight sections at the ends by hot drawing along a horn-shaped core on specialized hydraulic presses or by stamping.

Steeply curved bends can be installed on process pipelines of all categories.

Bent bends (see Fig. 2.1, b) are made from seamless and welded flexible pipes on pipe bending machines in a cold and hot state. Since the inevitable thinning of the wall occurs during the manufacture of such bends, the bending radius has to be made at least 2Dy. Bent elbows have straight sections at the ends, which is caused by bending technology.

Bent seamless bends can be installed on process pipelines of all categories. However, the production of bent bends is more labor-intensive than steeply curved ones, so they are recommended for use on pipelines for which steeply curved bends are not available (for pipelines made of alloy steels, pipelines for special purposes), and also when the project requires a large bending radius.

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2.2. BRANCHES (TEES) ON PIPELINES A branch (tee) is a shaped part of a pipeline designed to merge or divide the flow of a substance at an angle of 90 °.

Branches (tees) according to their design are divided into equal bore - without reducing the diameter of the branch and transitional - with a decrease in the diameter of the branch. The variety of tee designs is due to the fact that the strength of the pipeline section in the places where the hole occurs is sharply reduced.

Depending on the safety margin of the pipeline and the ratio of the diameter of the branch to the diameter of the main line, local reinforcement may be required. For this purpose, special reinforcing elements are used.

The greatest reduction in the strength of pipelines occurs in equal welded branches obtained by insertion without reinforcing elements (Fig. 2.2).

Such connections are usually used for nominal pressure Py up to 2 MPa. For higher pressures, either a reinforced body is used, which is made in the form of separate welded tees (Fig. 2.3), or the insert is strengthened with an overhead collar (Fig. 2.4).

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If higher strength and reliability of the tee is required, then you will have to abandon the weld altogether and switch to seamless mating of the branch neck. This is achieved, for example, by stamping (Fig. 2.5).

2.3. TRANSITIONS IN PIPELINES A transition is a shaped part of a pipeline designed to expand or narrow the flow.

Transitions by design are divided into concentric and eccentric.

Concentric transitions (Fig. 2.6, a) are used for vertical pipelines, and eccentric (Fig. 2.6, b) for horizontal ones.

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The use of eccentric transitions avoids the formation of so-called “bags” in a horizontal pipeline and facilitates product removal when it is turned off.

2.4. PLUGS Sooner or later, any production stops for planned repairs. At this time, equipment is replaced or repaired. If the device is cut off from the network, the resulting hole in the pipeline must be welded to prevent the pumped substance from entering the environment. To do this, plugs are used (the pipeline is plugged). You can also insert a plug between the flanges.

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The plug is designed to shut off the flow for a long period of time. In Fig. 2.7 shows elliptical and flat plugs.

2.5. FLANGES During the operation of pipelines, maintenance and repair, there is often a need to connect (disconnect) individual parts of pipelines, remove fittings and instrumentation for replacement or repair. For these purposes, detachable connections are used - flanged, threaded, etc.

Flanges are the most common type of detachable pipeline connection. They have a simple design and are easy to assemble and disassemble.

The disadvantage of flanged connections compared to welded ones is:

· higher labor intensity and cost of production;

· less reliability in operation, since fluctuations in the temperature or pressure of the transported product may cause depressurization and, as a consequence, a leak.

In this regard, the use of flange connections in pipelines is limited. They are used:

· for connection to flanged fittings;

· to equipment fittings;

· in pipelines that require periodic disassembly to clean the internal cavity or replace areas of increased aggressiveness;

· for temporary or periodically dismantled pipelines.

The type of flanges and design of sealing surfaces are chosen depending on the operating parameters and physical and chemical properties of the transported product.

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In order to ensure the interchangeability of flanges of all types, their connecting dimensions (outer diameter, bolt circle diameter, number and diameters of bolt holes) are standardized and set the same for the same nominal pressures and passages, regardless of the design and material of the flange.

To create the necessary tightness of the pipeline flange connection, a gasket is installed between the flanges, and the contacting sealing surfaces are given a special shape. Depending on the pressure and properties of the transported product, six types of sealing surfaces are provided (Fig. 2.8).

There are several ways to connect the pipe and the flange sealing surface. The most commonly used are flat welded flanges (Fig. 2.9, a).

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Butt-welded flanges (Fig. 2.9, b) are widely used in process pipelines made of carbon or alloy steel, especially for pipelines with a nominal pressure of up to 20 MPa.

The use of butt-welded flanges allows you to reduce the labor intensity of welding by 2 times, since they are connected to the pipes with one weld, and flat welded ones with two.

One of the problems with flange connections is ensuring alignment (coincidence) of the bolt holes during installation. To simplify the installation of a flange connection, loose flanges are used (Fig. 2.9, c, d). They are performed either on a welded ring (see.

rice. 2.9, c) or on a flanged pipe (see Fig. 2.9, d). But the production of loose flanges is more labor-intensive than butt-weld flanges, and requires more metal consumption. The only advantage of this connection is easier alignment of the bolt holes by rotating the flange around its axis.

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To assemble flange connections, fasteners are used - bolts, studs, nuts and washers. Studs have advantages over bolts, since with studs, when they are tightened, the stresses are distributed more evenly, and with bolts, stress concentration occurs in the places where the rod passes into the head. In addition, studs can be installed in hard-to-reach places. In Fig. Figure 2.10 shows the main types of pipeline flange connections.

2.6. COMPENSATORS It is well known that when temperature changes, objects change their linear dimensions. The magnitude of this change depends on the length of the product l, the temperature difference Dt and the coefficient of linear expansion of the metal. The calculation formula for determining the change in the length of the pipeline section is Dl = alDt. (2.1) To reduce stress in the pipeline during thermal changes in its length, the self-compensation method is used. In this case, the pipeline is designed in such a way as to ensure the free movement of its elements due to bends and turns of the route. However, self-compensation often does not provide the necessary reduction in loads in the pipeline. Then U-shaped compensators are used (Fig.

2.11). They are made by bending or welding of steel pipes.

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The main geometric dimensions of the compensator are the reach H, the length of the backrest K and the radius of curvature of the knees R, which should be equal to R=4Dн.

3. PIPELINE FITTINGS

3.1. CLASSIFICATION OF PIPELINE FITTINGS

Pipeline fittings are devices mounted on pipelines, tanks, boilers, units and other installations designed to shut off, distribute, regulate, mix or discharge media flows.

Designers have created a huge number of different types of pipeline fittings. This number is so large that it is difficult to carry out even its usual classification. This classification can be based on various characteristics: scope of application, principle of operation, nature of the functions performed, method of connection to the pipe, and others.

Here we will not consider all these signs - they are described in detail in. The most important thing, in our opinion, is to know what this or that fitting should do, so we will only consider the classification of fittings according to their functionality and the method of blocking the flow.

So, according to the nature of the functions they perform, fittings are divided into the following main classes.

1. Shut-off valves designed to completely shut off the flow of medium in the pipeline. In terms of the number of units used, it accounts for about 80% of all fittings. Shut-off valves also include test and drain valves, or control and drain valves, designed to check the level of the liquid medium in containers, take samples, release air from devices, and drainage. Characteristic of this fittings is the small value of the nominal passage diameter (Dу). Test fittings are produced in large quantities.

2. Control valves designed to regulate the flow of the working medium in order to maintain process parameters (temperature, pressure, composition of materials involved in the process) within a given range. Control valves include control valves and valves, pressure regulators, and level regulators. Regulating valves also include throttling valves, designed to operate at large pressure drops.

3. Distribution and mixing fittings used to distribute the flow of media in certain directions. This includes distribution valves (distributors) and distribution taps. Distribution and mixing fittings are also used for mixing various media, such as cold and hot water.

4. Safety valves used to protect the serviced object from excessive pressure increases by releasing an excess amount of the working medium. Safety valves include safety valves, impulse safety devices, diaphragm burst devices, and bypass valves.

5. Protective fittings designed to protect equipment from emergency changes in working environment parameters. Unlike safety valves, when emergency conditions occur, they close and turn off the serviced area, thereby protecting it from unacceptable influences. Safety valves include safety (shut-off) valves, check valves, shut-off valves. Various fast-acting types of shut-off valves (valves, gate valves, dampers, taps) are often used as protective fittings.

6. Phase separating and mass separating fittings, designed for automatic separation of working media depending on their phase and condition. This includes condensate drains, air vents and oil separators.

According to the method of blocking the flow of the medium, the fittings are divided into the following main types.

1. A gate valve is a shut-off valve in which the valve has the shape of a disk, plate or wedge, and moves reciprocatingly along its plane, perpendicular to the axis of the medium flow. Gate valves are designed to completely shut off the flow of the working medium and are one of the most common types of shut-off pipeline valves installed on process and main pipelines. The locking element in valves moves back and forth, perpendicular to the direction of flow of the working medium and has two extreme operating positions - “open” and “closed”. The operating principle of the valve is shown in Fig. 3.1, a.

2. Valve2 - a valve in which the valve has the shape of a plate or cone and moves back and forth parallel to the axis of the medium flow in the seat of the valve body. A valve in which the valve is moved manually using a screw pair (spindle and fixed running nut) is called a valve. The operating principle of the valve is shown in Fig. 3.1, b, and the valve device is illustrated in Fig. 3.2.

Depending on their purpose, valves are divided into:

· shut-off valves – designed to completely block the flow;

· control valves – designed for proportional (analog) flow control;

· safety – designed for automatic release of the medium when the pressure rises above the set one;

· bypass – designed to maintain the pressure of the medium at the required level by bypassing it through pipeline branches;

· shut-off valves – designed to quickly shut off the flow;

· breathing – designed both to release the vapors accumulated in the tanks and to let air into them during “large” and “small” breathing3.

· reverse – designed to prevent the reverse flow of the medium.

Among all this variety, we are primarily interested in valves, since, along with gate valves, they are widely used in oil refining and petrochemical enterprises to control flow rates.

3. Valve - a valve in the shape of a body of rotation (or part of it), rotates around its axis, located perpendicular. In internal combustion engines, pumps, compressors, a valve is usually called a part in the form of a disk with a rod sliding in a guide hole.

This valve is designed to block the flow of the medium by moving along the axis and landing in the seat. “Big breathing” in tanks is associated with a rise or fall in the liquid level, and “small breathing” is caused by changes in ambient temperature (day and night).

polar to the axis of the medium flow. The operating principle of the crane is shown in Fig. 3.1, c.

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4. Valve (rotary disc valve)4 - a disc-shaped valve that rotates around an axis located in the plane of the valve or parallel to it. The operating principle of the damper is shown in Fig. 3.1, g.

The old name for this type of valve is a damper; now the term “disk valve” or “rotary disk valve” is more often used.

3.2. MAIN ELEMENTS OF PIPELINE FITTINGS

Various reinforcement designs include parts and assemblies that have a general purpose and the same name. Let's consider them using the example of a normal valve (see Fig. 3.2).

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The body is a part that replaces a piece of pipe with a length equal to the distance between the ends of the connecting flanges or pipes for welding to the pipeline. The body together with the lid forms a cavity hermetically isolated from the external environment, inside which the shutter moves.

A valve is a moving part of a working body - a part or a structurally combined group of parts designed for hermetically sealing two sections of a pipeline by closing the passage hole in the flow part of the housing. For this purpose, the body is provided with a seat equipped with an O-ring.

The shutter in valves is a valve plate (for small sizes it is called a spool), in valves it is a wedge or a disk, or two disks at the same time, in taps it is a plug in the form of a cone, cylinder or ball.

The cover is a part used to seal the hole in the body through which the shutter is installed. In controlled valves, the cover has a hole for the spindle.

The spindle is a part that is a rod equipped with a thread, with the help of which the shutter is controlled. A spindle that does not have a thread is called a rod.

The running nut also has a thread and forms a threaded pair with the spindle to move the shutter and install it in the required extreme or intermediate position (the thread is self-locking).

Oil seal is a device designed to seal the movable interface of the cover with the spindle. The stuffing box got its name due to the fact that the packing of the stuffing box for water and steam is usually impregnated with fatty compounds. The stuffing box cover is a part designed to compress the packing; it can be whole and composite. In the latter case, the oil seal cover consists of a pressure sleeve and an oil seal flange. The packing sleeve is the support for the packing. Pressure studs, anchor or hinged gland bolts with nuts are used to tighten the gland packing. In valves and valves intended for hazardous or harmful environments, instead of a gland, a bellows5 assembly is used, which ensures absolute tightness of the movable connection of the spindle with the cover.

A flywheel is a part (usually cast) that looks like a rim with a hub, which is connected to the rim by spokes. Serves for manual control of valves. Small flywheels are manufactured in the form of a solid disk.

Bellows is a thin-walled metal corrugated shell (“accordion”);

expands or contracts under the influence of the pressure difference between inside and outside.

3.3. COMPARATIVE CHARACTERISTICS OF SHUT-OFF VALVES

When the magnitude or direction of the flow velocity vector changes, its energy is lost. Network elements in which such loss occurs are called local resistances6. So, any fittings have hydraulic resistance, i.e.

causes loss of flow energy. There are two extreme cases here.

1. The fittings are installed on a pipeline with a high flow rate. In this case, it is necessary that the hydraulic resistance of the reinforcement be minimal in order to avoid high energy costs for transport.

2. The fittings are installed in dead-end sections of the pipeline, designed for sampling, discharging or draining the transported medium and are used periodically. In such cases, the loss of energy is not of fundamental importance.

To characterize the amount of energy loss in the reinforcement, the coefficient of hydraulic resistance is introduced. The greater its value, the greater, other things being equal, the loss of pressure (pressure). Approximate values ​​of the coefficient for various types of shut-off valves are given in table. 3.1.

From those given in table. 3.1 of the values ​​of the hydraulic resistance coefficients it follows that in pipelines through which the flow moves constantly and at high speed, it is advisable to install gate valves, taps or dampers as shut-off valves. On dead-end pipelines, in which the flow rarely moves and its speed is not of fundamental importance, it is better to install valves.

In table 3.2 provides a comparative description of various types of locking devices.

For details, see the hydraulics section in the course “Processes and apparatus of chemical production”

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3.4. TYPICAL DESIGNS OF SHUT-OFF VALVES

Valves. Let us recall that a valve is a type of valve designed to manually control the flow rate. The valves use a “disc-seat” pair as a shutter. The disk is mounted on a spindle, which moves back and forth along the running thread perpendicular to the plane of the seat (see Fig. 3.1, b, 3.2).

The use of running threads, which have the property of self-braking, allows you to leave the valve in any position with confidence that this position will be maintained and will not spontaneously change under the influence of environmental pressure.

The valve has a simple design and provides high density in the closed position. The industry produces valves with dimensions up to Dy=200 mm. But it is most advisable to install valves on small diameter pipelines. As the nominal diameter of the pipeline increases, starting from Dу=50 mm, valves give way to gate valves.

This is explained by the fact that at large nominal passage diameters and high pressures, the force on the spindle increases so much that the valve becomes difficult to control.

A positive quality of the valve is the relatively small shutter stroke required to fully open the valve.

For this purpose, it is enough to raise the valve plate by the diameter of the hole in the seat, while to open the valve it is necessary to move the wedge or disk by an amount equal to the diameter of the hole, i.e. four times larger, so the valve has a significantly smaller overall height than a valve of the same diameter, but its length (the distance between the outer ends of the valve passage flanges) is greater than in a valve, and this difference increases with increasing passage diameter.

Valve designers have created a large number of types of valves designed to work in specific conditions. In Fig. 3.3 an attempt is made to show the classification of valves used in industry.

Based on their location on the pipeline, there are straight-through valves (Fig. 3.4, a) and angle valves (Fig. 3.4, b).

Continuous valves are installed on a horizontal or vertical section of the pipeline, corner valves are installed at the point where the pipeline turns. Angle valves have lower hydraulic resistance, but their scope of application is limited to rotary sections of the pipeline.

Both straight and angle valves cause a sharp change in flow path, which leads to significant pressure losses in them. In order to reduce hydraulic resistance, direct-flow valves were designed (Fig. 3.5). Their spindle is located at an angle to the axis of the flow passage. But for reducing resistance you have to pay by increasing the spindle stroke: to fully open the valve, this stroke for a direct-flow valve is significantly greater than for a normal valve.

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As a rule, valves are designed and installed so that the movement of the medium occurs “under the valve”, i.e. towards the movement of the valve disc when closing (see Fig. 3.1, a and 3.2). Reverse movement of the medium, i.e. “on the valve” (see Fig. 3.1 b), is rarely carried out and is used mainly in large-diameter valves, for non-critical installations, in order to relieve the spindle from large longitudinal compression forces.

For connection to pipelines, valves are equipped with either a flange or couplings with internal threads. For power plants, valves are welded into the pipeline, for which they are equipped with appropriate pipes.

Valves are most often operated manually using a handwheel. Recently, valves with electric, electromagnetic, pneumatic and hydraulic drives have become increasingly used. In Fig. Figure 3.6 shows the design of a valve with an electric drive.

Rice. 3.6. Motorized valve

Valves. Let us recall that a valve is a fitting with a shutter in the form of a sheet, disk or wedge, which moves along the sealing surfaces of the body perpendicular to the flow axis.

Valves are more common and are usually used for pipelines from Dу=50 mm to Dу=2000 mm. The positive qualities of a valve are its comparative simplicity of design and low hydraulic resistance compared to valves, therefore, in the petrochemical and oil refining industries, valves are usually used as a shut-off and control device. The disadvantage of valves is their relatively large height, therefore, in cases where the valve must, as a rule, be closed and opening is rare, in order to save space, valves are used with a diameter of 200 mm. The operating principle of the valve is shown in Fig. 3.7, and its structure is shown in Fig. 3.8.

–  –  –

Externally, it is quite simple to distinguish a valve from a valve: the valve’s flywheel rotates and extends along with the spindle, and when the valve’s flywheel rotates, the spindle does not rotate, but only moves out of the body (when opening) or enters it (when closing).

Designers have created a wide variety of valves.

–  –  –

They can be classified according to various criteria (Fig.

3.9). Typically, the classification is based on the following characteristics:

· design of the locking element (shutter);

· location of the chassis;

· type of drive;

· method of connection to the pipeline.

–  –  –

According to the shape of the shut-off body, valves are divided into wedge and parallel.

A wedge gate valve has a valve in which the sealing surfaces are located at a slight angle to each other, forming a wedge. In a parallel valve, the sealing surfaces are parallel to each other.

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