Technical examination of boilers. Guidelines guidelines for testing the hydraulic stability of once-through power and hot water boilers

Hydraulic testing of boilers carried out after completion of all welding work and before installation of insulation and application of protective coatings. When testing for strength and density, taps and valves (spring) are blocked or muffled. The boiler is filled with water at a temperature not lower than plus 70C. And not higher than 40-500 C. The temperature in the boiler room should not be lower than + 50C. The pressure is created by a hand pump with a check on the control pressure gauge. The pressure rise time is 10-15 minutes. Inspection is carried out at working pressure (10 min), at test pressure (5 min) and again at working pressure. If during the inspection no leaks, ruptures of welds, residual deformations and other defects are found, then the boiler is recognized as serviceable. The test results are recorded in the boiler's cord book.
The value of the test pressure Ppr for boilers is set for two cases: - during manufacture or repair; - assembled with fittings. The values ​​of test pressures depend on the type of boilers and their operating conditions. For boilers, superheaters, economizers and their elements operating at temperatures up to 3500C, the test pressure is equal to 1.5 of the working pressure Рр, but not less than (Рр +0.1) MPa. And in assembled form with fittings - 1.25Rp, but not less than (Rp +0.1) MPa.
For superheaters and their elements operating at temperatures above 3500C, the test pressure is calculated by the formula:

where is the yield strength of the material at a temperature of 3500C, MPa.
is the yield strength of the material at operating temperature, MPa.
The fittings of the boilers are tested for double working pressure, when testing for sealing closing - at a pressure of 1.25 Pr. The feed valves of the boilers are tested for a pressure of 2.5 Pp. And gas cavities of utilization boilers - with air under pressure of 0.01 MPa.
After hydraulic tests a steam sample of the boiler is made at operating pressure. Safety valves must be adjusted to the following opening pressures (in MPa):

During steam tests, the pressure is increased in stages and with stops during which intermediate inspections are made. At operating pressure, the boiler is checked for at least 30 minutes.
Mooring tests of the boiler are carried out after the steam test. Their purpose is to adjust and test in operation on a working boiler all systems, devices and automation equipment. During mooring tests, the reliability of the boiler plant is evaluated and the operating parameters are determined, as well as the thermal expansion of the boiler on the supports is controlled.
The final stage is sea trials. At the same time, the reliability and safety of the operation of the entire boiler plant in certain modes are determined and comprehensive thermal engineering tests are carried out.
When repairing boilers full program tests are determined by the Register. The scope of the program depends on the category of the repair being carried out.

How often should hydraulic tests of boilers be carried out? Frequency of hydraulic tests of boilers

Hydraulic testing of boilers and pipelines

In accordance with the rules of the USSR Gospromatomnadzor, boilers, superheaters and water economizers operating under an overpressure of more than 0.07 MPa, as well as hot water boilers with a water heating temperature above 115 ° C, are registered with the USSR Gospromatomnadzor bodies and subjected to technical examination.

The technical examination consists of an internal inspection and a hydraulic test of the units. Superheaters and economizers, constituting one unit with the boiler, will be examined simultaneously with it.

The boiler is inspected inside, checking for cracks, ruptures, metal corrosion, violations of rolling and welded joints, and other possible defects.

A hydraulic test is performed to check the strength of the pressurized elements of the boiler and the tightness of their connections. Drums and chambers of steam boilers, screen and convective pipe systems, superheaters and water economizers are subjected to hydraulic testing. Hydraulic tests of individual elements and blocks, carried out on an enlarged assembly site, do not exempt the installed equipment from hydraulic testing.

Before the start of the hydraulic test, all hatches and manholes of the boiler are closed, on which permanent gaskets are installed, shut-off valves that disconnect the boiler unit from other devices and pipelines, and plugs are installed between the boilers and safety valves. For testing, the boiler is filled with water at a temperature not higher than 60 and not lower than 5 °C at an ambient air temperature not lower than 5 °C. When filling the boiler with water, air is removed through a safety valve or a special air cock.

To fill the boiler with water and create a test pressure, which is increased gradually and smoothly, an electric pump or a manual hydraulic press is used. The test pressure is maintained for 5 minutes, after which it is gradually reduced to the working one. In the event of a pressure drop, find out the place where the water passes. With a slight decrease in pressure due to leaky fittings, the hydraulic test can be continued, while the test pressure is maintained by pumping water, but not more than 5 minutes. The water pressure in the boiler is measured by two tested pressure gauges, one of which must be a control one.

The boiler unit is inspected at operating pressure, tapping the welds with light blows of a hammer weighing no more than 1.5 kg. Special attention pay attention to the density of welds, rolling and flanged joints. If, when testing the boiler, shocks, noise, knocking are heard inside it, or a sharp drop in pressure occurs, the hydraulic test is stopped to detect damage.

The boiler is considered to have passed the hydraulic test if there are no breaks, leaks or deformations in it. If water droplets appear in the welds or pipe walls or they fog up, the boiler is considered to have failed the test. Boilers that have passed the hydraulic test can be bricked up and thermal insulation work can be performed on them.

Permission to operate the boiler, superheater and economizer is issued on the basis of the results of the technical examination.

The technical examination of pipelines consists in checking the installation documentation, external examination and hydraulic testing of the installed pipelines. The technical examination of the installed pipelines is carried out by the controller engineer of the USSR Gospromatomnadzor, pipelines that are not subject to registration with the USSR Gospromatomnadzor bodies - the installation site management with the participation of a representative of the customer's technical supervision.

External inspection and hydraulic testing of pipelines from seamless pipes is allowed if they are already insulated and welded joints and flange connections are available for inspection. Pipelines made of welded pipes are subjected to a hydraulic test before thermal and anticorrosive insulation is applied to them. Welded joints are subjected to heat treatment prior to hydraulic testing.

Hydraulic testing of installed pipelines is carried out to check the strength and tightness of their connection. Before testing large-diameter pipelines, it is checked whether the supports and suspensions can withstand the additional load from the weight of water, which will be significant for large pipe diameters. In addition, attention is paid to the protection against additional bending forces of fragile lens compensators and cast iron fittings.

For supply pipelines, the working pressure is taken as the pressure developed feed pumps with closed valves.

When preparing a pipeline for a hydraulic test, the following is checked: whether welding work and heat treatment of welded joints are completed; whether gaskets are supplied in flange connections and whether they are tightened. Then, a scheme of the tested pipeline is assembled and, after checking the serviceability of the hydraulic press, it is connected to a water supply source, and the pressure pipe is connected to the tested pipeline. At the lowest point of the test section there must be a drain valve to empty the pipeline after the test, and at the highest point - an air cock to remove air during filling with water. A serviceable sealed pressure gauge is installed on the discharge pipeline, the verification period of which has not expired. When testing pipelines and vessels, proven spring pressure gauges with an accuracy class of at least 1.5 and a case diameter of at least 150 mm are used.

The assembly of the circuit for testing consists in the fact that the pipeline under test is disconnected from the existing or unmounted pipelines and equipment and all shut-off devices in the test section are opened, except for the valves on the drainage and drain lines, which must be closed. If there are safety valves on the pipeline, plugs are installed between them and the pipeline.

For hydraulic testing of pipelines, hydraulic pumps with electric drive and manual hydraulic presses are used.

The pipeline is slowly filled with raw water at a temperature not lower than the ambient temperature, as this will prevent it from sweating. At the same time, the air vents open completely. After removing the air, the air vent is closed and the pressure is gradually increased to the test one, keeping it for 5 minutes, then the pressure is reduced to the working one. Further, at operating pressure, welded and flanged joints are examined. During inspection, the welded joints are tapped with a hammer and made sure that there are no leaks, cracks, fistulas and other defects. If defective places are found, they are marked with chalk so that after the pressure is removed, they can be easily detected. Defective places in the welds are removed and re-welded. It is not allowed to correct defects before the pressure is reduced to zero.

Flanged joints and gland seals in which a leak was detected are disassembled, the cause of the leak is identified and eliminated. After elimination of defects, the hydraulic test is repeated.

The results of the hydraulic test are considered satisfactory if no pressure drop has occurred (verified by the pressure gauge) and if no leaks or sweating are found in welds, pipes, fittings and fittings. A hydraulic test cannot be performed at a negative ambient temperature, as this may defrost and break fittings, especially cast iron, and small pipes. For the same reason, from pipelines to winter time in unheated premises at the end of the hydraulic test, immediately and carefully drain the water. Areas that do not have a free drain (coils, concave sections) are blown with compressed air. To drain water, flange connections are dismantled near the cast-iron fittings. When the water is lowered, the air vents open.

The results of the inspection of pipelines and permission to put them into operation are recorded in the passport.

Installation of boilers - Hydraulic testing of boilers and pipelines

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3. Hydraulic testing of boilers.

To check the strength of the structure, the quality of its manufacture, all elements of the boiler, and then the boiler as an assembly, are subjected to hydraulic tests with a test pressure ppr. Hydraulic tests are carried out at the end of all welding work, when insulation and protective coatings are still missing. The strength and density of welded and rolling joints of elements is checked by test pressure pp = 1.5pp, but not less than pp + 0.1 MPa (pp is the working pressure in the boiler).

The dimensions of elements tested with a test pressure of pp + 0.1 MPa, as well as elements tested with a test pressure higher than indicated above, must be subjected to a verification calculation for this pressure. In this case, the stresses should not exceed 0.9 of the yield strength of the material σts, MPa.

After the final assembly and installation of fittings, the boiler is subjected to a final hydraulic pressure test pp = 1.25pp, but not less than pp + 0.1 MPa.

During hydraulic tests, the boiler is filled with water and the working water pressure is brought to the test pressure ppr with a special pump. The test results are determined by visual inspection of the boiler. As well as the rate of pressure drop.

The boiler is recognized as having passed the test if the pressure in it does not drop and no leaks, local bulges, visible changes in shape and residual deformations are detected during inspection. Sweating and the appearance of small water droplets at the rolling joints are not considered leaks. However, the appearance of dew and tears at the welds is not allowed.

steam boilers after installation on the ship, they must be subjected to a steam test at operating pressure, which consists in the fact that the boiler is brought into service and checked in operation at operating pressure.

Gas cavities of utilization boilers are tested with air at a pressure of 10 kPa. Gas ducts of auxiliary and combined PCs are not tested.

4. External inspection of steam boilers.

External inspection of the boilers complete with apparatus, equipment, service mechanisms and heat exchangers, systems and pipelines is carried out under steam at operating pressure and, if possible, combined with a test of the operation of the ship's mechanisms.

During the inspection, it is necessary to make sure that all water-indicating devices (water-gauge glasses, test taps, remote water level indicators, etc.) are in good condition, as well as that the upper and lower blowing of the boiler is working properly.

The condition of the equipment, the serviceability of the drives, the absence of steam, water and fuel leaks in glands, flanges and other connections should be checked.

Safety valves must be tested in operation for operation. The valves must be adjusted to the following pressures:

Rotkr ≤ 1.05 Pwork for Pwork ≤ 10 kgf/cm2;

Rotkr ≤ 1.03 Pwork for Pwork > 10 kgf/cm2;

The maximum allowable pressure during the action of the safety valve Pmax ≤ 1.1 Rrab.

The safety valves of superheaters must be adjusted to operate with some advance of the boiler valves.

The manual actuation of the blasting must be checked in action. safety valves.

With positive results of external examination and verification in operation, one of the boiler safety valves must be sealed by the inspector.

If it is not possible to check the safety valves on the disposal boilers in the parking lot due to the need for a long operation of the main engine or the impossibility of supplying steam from the auxiliary fuel-fired boiler, then the adjustment and sealing of the safety valves can be checked by the shipowner during the voyage with the issuance of the relevant act.

During the survey, the operation of the systems should be checked. automatic regulation boiler plant.

At the same time, you should make sure that the alarm, protection and blocking devices work flawlessly and are triggered in a timely manner, in particular when the water level in the boiler drops below the permissible level, when the air supply to the furnace is interrupted, when the flame in the furnace is extinguished and in other cases provided for by the automation system.

You should also check the operation of the boiler installation when changing from automatic to manual control and vice versa.

If during the external examination defects are found, the cause of which cannot be established by this examination, the inspector may require an internal examination or hydraulic test.

studfiles.net

types, technical examination and diagnostics of equipment

For the normal functioning and efficient use of boilers and units that heat water, it is imperative that the mode and adjustment tests of hot water boilers are carried out. The essence of such tests is to select the most optimal modes of operation of the equipment that is involved in the heating system. Content

Regime and adjustment tests of hot water boilers

Tests should be carried out after the installation of all equipment, completion of installation of commissioning mechanisms, as well as after appropriate training of workers in the correct and safe operation mechanisms and units of this system.

Regime and adjustment work should be carried out after installation or repair of the boiler. In exceptional cases, such work may also be carried out during the operation period.

Regime and adjustment tests of hot water boilers are carried out to select best modes works, to compile a regime map and to draw up recommendations for improving the efficiency of equipment.

In the process of setting up the units, fuel consumption, flow rate, pressure, fuel combustion temperature and some other parameters are checked. physical process fuel combustion.

Hot water boilers are installed for space heating. Their main advantage is that they can be installed where there is no central heating.

Read more about wood-fired boilers here.

After the necessary work calculations are carried out to determine the minimum and maximum indicators of the efficiency of the boiler house.

The main objectives of such events are: familiarization with the data of the registration certificate and the operation of the unit, drawing up a test method, drawing up a consistent program, conducting trial and preparatory work, carrying out the main work, calculating the results and compiling a report and regime maps.

Regime and adjustment measures should be carried out: for boilers on liquid and solid fuels - 1 time in 5 years; for gas boilers - 1 time in 3 years.

Mode tests

Mode tests of water-heating units are carried out to install an energy-saving method that does not require large cash costs.

These activities are also called environmental and thermal engineering. During the adjustment, shortcomings in the operation of the entire water heating system are revealed.

After receiving all the necessary data, it is developed integrated system to improve the efficiency of the devices.

The need for routine adjustment of boilers:

• detection and elimination of defects of all equipment;
• minimizing the release of toxic gases into the atmosphere;
• increase in the efficiency of the heating device;
• increase the service life of the mechanisms and units of the system;
• examination performance characteristics of the entire water heating installation, declared in the documentation of the manufacturer and the technical passport of the equipment.

Mode tests of solid fuel boilers are carried out 1 time in 5 years, and gas - 1 time in 3 years.

The advantages and benefits of a heating water boiler are beyond doubt, but like any technical means, boilers periodically need maintenance.

How to correctly calculate the power of a gas boiler, read here.

Technical certification of water heating devices

Technical examination (TO) of hot water boilers and hot water equipment is carried out in order to check the operability of all mechanisms and to avoid accidents due to technical reasons.

Maintenance can be carried out in two ways - visual and hydraulic. With visual - internal and external inspection is carried out. With hydraulic - the boiler must be under test pressure for several minutes.

A hydraulic test must be carried out only after the internal and external tests have been carried out.

Technical examinations are carried out: primary - the first time before the boiler is put into operation; periodic - once every eight years for control, and extraordinary - at the end of the service life, in case of accidents or explosions, after natural disasters. Such events are carried out only by an organization that has a license from Gostekhnadzor, specialists and special equipment.

The purpose of testing hot water boilers is to determine the actual operational, thermal and environmental performance.

See the diagram of the hot water boiler here.

For a qualitative inspection of water heating installations, work should be carried out in the following sequence:

• verification of technical documentation and preparation of a maintenance action plan;
• conducting an external examination and measuring all the necessary parameters;
• assessment of the technical condition of all equipment.

The technical condition of the boiler is checked once every 5 years, and hydraulic tests and measurement of the geometric dimensions of the unit are carried out once every 10 years.

Technical diagnostics of hot water boilers

Technical diagnostics water-heating devices are carried out for the purpose of safe operation of mechanisms. In the event of a defect, accident or expiration of the service life - to determine the limit service life.

Such a procedure can be carried out only by those public and private organizations that have permission from Gostekhnadzor and with the availability of specialists and equipment for diagnosing.

Procedure for diagnosing heating devices:

• Taking the water heater out of operation, cooling and disconnecting from other units.
• Cleaning of soot inside and outside those surfaces on which diagnostics should be carried out.
• If necessary, the insulation and lining of the walls are removed and internal organization boiler to ensure technical diagnostics.

Heat recovery boilers are designed for the preparation of hot water for industrial and household purposes with a maximum design temperature of up to 115°C.

Read more about electric hot water boilers here.

The diagnostic devices used must be equipped with non-destructive testing elements that can accurately determine the presence of a defect, its location and size.

To measure parameters such as pipe deflection, diameter, deflections and sags of drums, special tools must be used that determine all dimensions to the nearest mm. To measure the wall thickness, it is necessary to use linear instruments that have an error of no more than 0.1 mm.

Technical diagnostics of metal and welds should be carried out with tools that have passed state testing and meet accepted standards.

Diagnosis should be carried out 1 time in 4 years.

Technical examination, diagnostics and operational and adjustment tests of hot water boilers and hot water equipment - a guarantee of the safe operation of the units, extension of the service life, concern for human health and avoidance of environmental pollution toxic gases and dust.

kotlotech.ru

Steam boiler testing. Hydraulic testing of a steam boiler after repair

Hydraulic tests of boilers are carried out after completion of all welding work and before installation of insulation and protective coatings. When testing for strength and density, taps and valves (spring) are blocked or muffled. The boiler is filled with water at a temperature not lower than plus 70C. And not higher than 40-500 C. The temperature in the boiler room should not be lower than + 50C. The pressure is created by a hand pump with a check on the control pressure gauge. The pressure rise time is 10-15 minutes. Inspection is carried out at working pressure (10 min), at test pressure (5 min) and again at working pressure. If during the inspection no leaks, ruptures of welds, residual deformations and other defects are found, then the boiler is recognized as serviceable. The test results are recorded in the boiler's cord book. The value of the test pressure Ppr for boilers is set for two cases: - during manufacture or repair; - assembled with fittings. The values ​​of test pressures depend on the type of boilers and their operating conditions. For boilers, superheaters, economizers and their elements operating at temperatures up to 3500C, the test pressure is equal to 1.5 of the working pressure Рр, but not less than (Рр +0.1) MPa. And when assembled with fittings - 1.25Рр, but not less than (Рр +0.1) MPa. For superheaters and their elements operating at temperatures above 3500С, the test pressure is calculated by the formula:

where is the yield strength of the material at a temperature of 3500C, MPa. is the yield strength of the material at operating temperature, MPa. The feed valves of the boilers are tested for a pressure of 2.5 Pp. And gas cavities of utilization boilers - with air under pressure of 0.01 MPa. After hydraulic tests, a steam sample of the boiler is made at operating pressure. Safety valves must be adjusted to the following opening pressures (in MPa):

During steam tests, the pressure is increased in stages and with stops during which intermediate inspections are made. At operating pressure, the boiler is checked for at least 30 minutes. Mooring tests of the boiler are carried out after a steam test. Their purpose is to adjust and test in operation on a working boiler all systems, devices and automation equipment. During mooring trials, the reliability of the boiler plant is evaluated and the operating parameters are determined, as well as the thermal expansion of the boiler on the supports is controlled. The final stage is sea trials. At the same time, the reliability and safety of the operation of the entire boiler plant in certain modes are determined and comprehensive thermal engineering tests are carried out. When repairing boilers, the full test program is determined by the Register. The scope of the program depends on the category of the repair being carried out.

morez.ru

Hydraulic tests of boilers test their strength

When dealing with any thermal equipment, regardless of the type of fuel and design, I want to have a guarantee of its reliability, durability and quality.

Hydraulic tests of boilers are just carried out to test the entire structure for strength. All elements of the thermal system are tested separately. Then, in assembled form, hydraulic tests of the boilers as a whole are carried out.

The test is carried out upon completion of welding work, when there are still no protective coatings, as well as insulation. The density and strength of rolling and welded joints are tested with a test pressure equal to 1.5 working pressures in the boiler. Stresses should not exceed the yield of the material by 0.9 of the limit.

After complete assembly and installation of all necessary fittings, the boiler is subjected to a final test at a pressure of 1.25 from the working one. The boiler plant is filled with water. The working pressure of the water is adjusted by a special pump to the test pressure. The result of the test is determined by visual inspection of the boiler plant and by the rate of pressure reduction.

The boiler is deemed to have passed the test if there is no pressure drop and if visual inspection no bulges, leaks, changes in shape or permanent deformations are detected. The appearance of small drops of dew in the metas of rolling joints and sweating are not leaks. The appearance of dew at the welds is unacceptable and is considered a leak.

Similar tests are carried out for all types of boilers, regardless of the model or fuel used. The purpose of hydraulic testing is to check the reliability of thermal equipment in an emergency. Boilers that do not pass the hydraulic test must be rejected.

Steam boilers are also tested. The check is carried out at operating pressure when the boiler is put into operation. Air with a pressure of 10 kPa is used to test the gas cavities of the utilization boiler. Gas ducts of combined and auxiliary steam boilers are not subjected to hydraulic tests.

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Boilers hydraulic test - Encyclopedia of Mechanical Engineering XXL

The pressure to which the boiler is subjected during the test should be controlled by two pressure gauges, of which one should be control. Simultaneously with the boiler, all its fittings are subjected to hydraulic testing.

General information about the technical supervision of steam boilers external and internal inspection of the boiler hydraulic test.

The strength and tightness of all elements of the boiler working under pressure are checked after repair of the boiler by a hydraulic test for working pressure.

Hydraulic test of the boiler. A hydraulic test is carried out in order to determine the strength of the pressure elements of the boiler and the density of their joints.

The purpose of the hydraulic (pneumatic) test is to check the strength and tightness of welded joints and all elements of boilers, steam heaters, pressure vessels, as well as steam and hot water product pipelines. Subject to hydraulic test

During hydraulic tests at a permitted working pressure of more than 0.5 MPa, the test pressure should be 1.25 working pressure, with a permitted pressure of more than 0.5 MPa - 1.5 working pressure. Typically, hydraulic tests are carried out at a positive temperature of at least 15 ° C when air is removed from the vessel or boiler. The pressure rise time should be at least 10 minutes and rise smoothly. The exposure time in this case is at least 20 minutes. After that, the pressure is reduced to the working one and the welds are inspected. Sometimes a phosphor is added to the liquid and the surface is examined under ultraviolet light. The surface itself is coated with indicator substances for better detection of leaks (starch, etc.).

Each boiler unit is subject to technical examination by an inspector of Gosgortekhnadzor. External inspection is carried out at least once a year, internal - at least once every three years, hydraulic pressure test (working plus 3 bar) - at least once every six years. An extraordinary survey is carried out after a major repair of the boiler elements operating under pressure.

In gas, gas-oil and dust-gas burners, the welds of gas elements, in addition to technical inspection and measurement, are subjected to a hydraulic strength test with an overpressure of 1 MPa and a density (tightness) test with kerosene according to GOST 3285-77. gas elements burners are also subjected to a leak test when installed together with a gas pipeline within the boiler in accordance with the requirements of the Safety Rules in the gas industry>.

Elements of factory and assembly blocks are exposed to intense oxygen corrosion after their hydraulic testing at boiler plants and assembly sites, as well as in assembly. The water remaining in them after this operation is often the cause of serious ulcerative lesions of the metal of the boilers before they are put into operation. Long-term storage of blocks on the installation site without their conservation also leads to dangerous corrosion before the boiler is installed.

When conducting hydraulic tests of the boiler at the end of the repair, the tract is filled without first draining the preservative solution. Before putting the boiler into operation, the solution is drained from all drained sections, its residues are displaced by condensate through the appropriate drains and the drainage tank, and from there they are sent to the waste water pit for neutralization. Washing the circuit is carried out until the content of hydrazine after the boiler is not more than 3 M g/kg, and the pH of the condensate is not more than 9.5.

It is advisable to perform hydraulic testing of boiler drums with inhibited water of the same composition as is used for pressure testing of pipe

Hydraulic tests of a number of corroded T rub showed their reduced mechanical strength; some pipes showed a leak at a pressure not exceeding the working pressure in the boiler. By etching defective pipes in a 10% hydrochloric acid solution, a weak corrosion resistance of the metal located under the shells was established.

As examples in Fig. Figures 1-6 and 1-7 show the screen block of the rear wall of the B-50-40 boiler furnace and the superheater block. Screen units up to 3 wide are supplied as finished heating surfaces with top and bottom chambers hydraulically tested at the factory.

Each hollow casting must be subjected to a hydraulic test pressure test in accordance with GOST 356-80. Hydraulic testing of castings that have undergone complete control by radiography or ultrasound at the manufacturer of castings can be combined with hydraulic testing of a boiler element or pipeline with a test pressure established by the NTD for the element or object.

Non-ferrous metals and alloys in boilers and pipelines are of limited use for the manufacture of small sizes of valves and instrumentation, and therefore the Rules for boilers and pipelines do not contain such detailed requirements for them as for steel and cast iron. The use of bronze and brass for parts of boilers and pipelines is permissible at a metal temperature not exceeding 250 ° C. The test pressure of hydraulic testing of valve bodies must comply with the requirements of GOST 356-80.

Regular processing of daily graphs of steam temperature behind each boiler (at a steam temperature of 450 C and above) allows you to timely take into account the operating time when the steam temperature exceeds the nominal one. During repairs, as well as when stopping the boilers for hydraulic testing, a thorough inspection of the pipes of the heating surfaces and their welded joints is carried out to identify pipes with large residual deformation, corrosion, ash wear, cracks in welded joints, unacceptable ovality and other defects. These data are analyzed by the metal laboratory, which also monitors

The purpose of the hydraulic test is to check the strength and density of welded joints, as well as all elements of boilers, superheaters, economizers, pressure vessels, and steam and hot water pipelines. Subject to hydraulic test

Hydraulic testing of boilers, superheaters, 39-959 609

All pipes for high and supercritical pressure boilers undergo a hydraulic pressure test, determined by the formulas

Control of welded joints of steam boilers and pipelines is carried out by external examination mechanical testing of samples cut from control plates, from control joints of pipes or from the products themselves; X-ray or gamma-ray transmission; ultrasonic flaw detection; macro- and microstructure studies; and hydraulic testing.

The calculation of steam boiler elements for strength should provide such dimensions of the calculated elements at which the stresses arising during operation and during hydraulic tests would not lead to residual shape distortions or to destruction.

Hydraulic testing of steam and hot water boilers

The boilers are subjected to a hydraulic test after their installation on the foundations, when the lining has not yet been made, all parts of the boilers are available for inspection and the boilers are not connected to the systems.

Hydraulic testing of vertical water-tube steam boilers is carried out before they are bricked up.

Based current rules Boiler supervision hydraulic testing of steam boilers with a working pressure above 0.7 atm is carried out according to table. 26.

Hydraulic testing of the boiler must be carried out with fittings installed on it.

Prior to the installation of the superheater in the coils, the absence of visible external defects is checked for the compliance of the outer diameters and wall thicknesses of the steel pipes with the design dimensions, the ovality of the coil pipes, the correctness of the bends and the permeability of the coils, as well as their tightness. The tightness is checked by hydraulic testing of each coil individually for a pressure exceeding the operating pressure of the boiler by 1.25 times.

After installation and alignment of the drums, work is carried out on rolling and assembling the boiler and screen pipes. They install the intra-drum equipment and fittings and test the boiler with hydraulic pressure. After a hydraulic test, the laying of the boiler lining is carried out.

Before assembly, all finned tubes and rolls are subjected to a hydraulic pressure test equal to 1.25 p 4-5 atm (where p is the operating pressure of the boiler in atm).

Hydraulic testing of butt-welded pipes is carried out at a pressure of 2p + 11 atm using devices for individual pressure testing (p is the working steam pressure in the boiler)

The change of rivets is carried out only with the knowledge and permission of the Gosgortekhnadzor inspection. When replacing more than 15 adjacent rivets, an extraordinary hydraulic test of the boiler with the participation of a representative of the Gosgortekhnadzor inspection is mandatory.

An internal inspection is carried out at least once every 4 years. When it is performed, first of all, the boiler drum is inspected from the inside. Hydraulic testing of the boiler for strength and density of its elements is carried out at least every 8 years. Hydraulic and testing is always preceded by an internal inspection. The test is carried out by raising the pressure above the working one in a boiler filled with water in order to check its strength and density. The results of the survey are recorded in the passport of the boiler unit.

At the end repair work the commission checks the acts of operational acceptance, internal inspection of the boiler drums, hydraulic testing, inspection of the boiler safety fittings and devices. Based on the test results of the boiler and the listed documentation, an act of general acceptance of the boiler from the overhaul is drawn up.

When installing the boiler block not on the foundation, but on the laying of the brickwork, an additional lifting of the assembled boiler will be required in this case, the installation sequence will change somewhat and will consist of the following stages of installing the boiler block on the foundation of the installation on temporary extensions of the side walls of the boiler piping frame and side platforms of the ladders for installing fittings installation of a cast-iron partition (if it was not mounted in the block) lifting the boiler block and installing it on temporary support trestles completion of assembly of the framing frame, platforms and ladders laying out the lining to the design mark of the bottom of the boiler support frame installation of the boiler block on the laying of the lining alignment of the installed boiler block pouring cement of the support frame of the steam superheater installation installation of intra-drum devices and a blowing device production of brickwork above the mark of the sole of the support frame of the boiler hydraulic testing of the boiler its pro alkalization and testing for vapor density.

qpeAax used for hydraulic testing must be free of oily and suspended solids. To eliminate corrosion of boiler elements made of pearlite steel, it is advisable to add one of the following mixtures of inhibitors to water [L. 24]

For anti-corrosion protection of internal surfaces of screen coils and steam heaters during their transportation and storage at the boiler plant after a hydraulic test, a volatile inhibitor is introduced into them, and their ends must be sealed with polyethylene caps. External surface these parts of the boiler must be protected

During hydraulic testing of boilers, vessels and pipelines, their strength and density are checked. However, in cases where increased requirements are imposed on the tightness of products, a pneumatic leak test is carried out using one of the following aquarium methods for washing the pressure drop of halogen leak detectors with a mass spectroscopic hot environment of stable traces of pressure increase in the pressure chamber.

For MTO of metal pipes, heating piping and steam boiler piping, it was proposed to use a hydraulic test with increased pressure. However, this raises a number of difficulties. For the implementation of the MTO, the plastic deformation should be 0.5-27o- However, the tolerance for the wall thickness of the pipes reaches 20-25%. The pipes of the heating surfaces have different safety margins at low temperatures, since, for example, the economizer is calculated according to the yield strength at a maximum operating temperature of up to 250-300 ° C, and the superheater is calculated according to the long-term strength limit at operating temperatures. The yield strength of steel of the same grade can vary according to the specifications over a very wide range. If a

It should be noted that only the reduction of the inverse balance of the boiler makes it possible to quantitatively identify heat losses and related shortcomings in its operation and outline ways to eliminate them. Therefore, this method is in many cases preferred, although it gives less accurate results in determining the efficiency of the boiler. Often tests are carried out on a forward and reverse balance. This combination is the most acceptable, as it allows you to get a complete picture, both qualitative and quantitative. Apparently, there is no need to give formulas for determining heat losses with exhaust gases, with chemical underburning, etc. . Currently, there is no approved unified methodology for thermal testing of contact economizers. The scope and nature of the measurements depend on the tasks involved. The most common types of tests are thermotechnical, aerodynamic and thermochemical, carried out when performing commissioning. The purpose of these tests is to determine the possible temperature of heating water and outgoing flue gases, maximum heat output without replacing the smoke exhauster, maximum performance on water while maintaining a normal hydraulic regime and the absence of a noticeable entrainment of water into the gas ducts. At the same time, studies of the quality of heated water are usually carried out simultaneously and changes in its composition, in particular, corrosion activity, are studied. Such tests necessarily accompanied the commissioning of the first industrial contact economizers.

Transportation of the boiler on dirt and paved roads is carried out by tractor traction using special sledges or carts. The montale of the boiler, when it arrives in assembled form, is produced in next order the boiler block delivered from the manufacturer is dragged and installed on the foundation, the correct installation of the boiler block is checked for connection with the foundation, the support frame is poured with cement mortar, the strapping frame, platforms and stairs are installed, the fittings are installed, the boiler is hydraulically tested, the cast-iron baffle is installed, the intra-drum device is installed and blowing device carry out brickwork, alkalize the boiler and test it for steam density.

mash-xxl.info

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mybiblioteka.su - 2015-2018. (0.006 sec)

The hydraulic test of the boiler is carried out in accordance with NP-046-03 after receiving satisfactory results of the internal inspection.

Together with the boiler, its fittings are tested: safety valve, water level indicators, shut-off devices. If it is necessary to install plugs, they are placed behind the locking elements. For hydraulic testing of the boiler, water with a temperature not lower than 5 °C and not higher than 40 °C is used.

When filling the boiler with water to remove air, the safety valve or air valve must be opened until water appears from it. If, as a result of filling the boiler with water, dew appears on its walls, then the test should be carried out only after the walls have dried.

During the test, the pressure in the boiler must be measured with two pressure gauges, one of which must have an accuracy class of at least 1.5.

The value of the test pressure is determined in accordance with paragraph 4.14.2 of NP-046-03. The rise in pressure to the test should be slow and smooth, without shocks. The total pressure build-up time must correspond to that specified in the installation and operating instructions for the boiler. The test pressure shall be controlled by two manometers. Pressure gauges must be of the same type, with the same accuracy class of at least 1.5, measurement limit and division value.

If it is not possible to achieve the required test pressure with a machine-driven pump, the pressure increase must be carried out with a hand pump. Upon reaching the test pressure, the water supply to the boiler is stopped and the supply line is blocked by a shut-off body; after that for 10 min. there should be no pressure drop.

After 10 min. the pressure is reduced to the working one and the boiler is inspected.

If noise, knocks or a sharp drop in pressure appear during the test period, the hydraulic test should be immediately stopped, their cause should be found out and eliminated.

The results of the hydraulic test of the boiler are considered satisfactory if:

• - cracks or signs of rupture (surface cracks, tears, etc.);
• - leaks, cracks, "tears" and "sweating" in the base metal, welded, riveted and rolling joints;
• - residual deformations of the walls;
• - visible pressure drop in the boiler on the pressure gauge.

If, during the inspection of the boiler, leaks are found in the rolling or riveting joints, it is necessary to check the defective joints using non-destructive methods flaw detection for the absence of intergranular cracks. Elimination of leaks is allowed only with satisfactory results of such a check.

In case of detection of defects by the inspecting person, depending on their nature, a decision may be made to suspend the operation of the boiler, put it into temporary operation, reduce the period of the next examination of the boiler, reduce the operating parameters, etc.

If, during the inspection of the boiler, defects are revealed that raise doubts about its strength, or defects, the cause of which is difficult to establish, the operation of such a boiler should be prohibited until the conclusion of a specialized organization on the causes of the appearance of these defects, as well as on the possibility and conditions of its further operation. The possibility of operating the boiler at reduced parameters must be confirmed by a strength calculation, and a verification calculation of the throughput of the safety valves and their outlet pipes must be carried out.

Hydraulic testing of vessels is carried out in accordance with NP-044-03 after obtaining satisfactory results of external and internal examinations.

The vessel and fittings installed on it are subjected to a hydraulic test.

Vessels having a protective coating (enamelling, lining) or insulation are subjected to an initial hydraulic test before coating or insulation is applied.

Vessels with an outer casing are subjected to a hydraulic test before the installation of the casing.

Hydraulic testing of vertically installed vessels may be carried out in a horizontal position, provided that the strength of the vessel body is ensured, for which the strength calculation must be performed by the developer of the vessel design, taking into account the accepted method of supporting the vessel during its hydraulic testing.

In combined vessels with two or more working cavities designed for different pressures, each cavity must be subjected to a hydraulic test with a test pressure determined depending on its design pressure.

The test procedure must be specified in the design of the vessel and specified in the manufacturer's instructions for the installation and operation of the vessel.

When filling the vessel with water, the air must be completely removed.

For hydraulic testing of vessels, water with a temperature not lower than 5 °C and not higher than 40 °C should be used, unless otherwise specified in the project.

By agreement with the developer of the vessel design, another liquid may be used instead of water.

The value of the test pressure is determined in accordance with paragraphs 4.6.3 - 4.6.5 of NP-044-03.

The test pressure shall be controlled by two manometers. Pressure gauges must be of the same type, with the same accuracy class of at least 1.5, measurement limit and division value.

The pressure in the test vessel should be increased gradually. The total pressure rise time and the holding time of the vessel under test pressure should be specified in the manufacturer's instructions for installation and operation of the vessel.

If it is not possible to achieve the required test pressure with a machine-driven pump, the pressure increase must be carried out with a hand pump. Upon reaching the test pressure, the water supply to the vessel is stopped and the supply line is blocked by a shut-off body; after that for 10 min. there should be no pressure drop.

After exposure under test pressure, the pressure is reduced to the design pressure, at which the outer surface of the vessel, all its detachable and welded joints are inspected.

Tapping of the body walls, welded and detachable joints of the vessel during the tests is not allowed.

In the cases provided for in paragraph 4.6.17 of NP-044-03, it is allowed to replace the hydraulic test with a pneumatic one, provided that this test is controlled by the acoustic emission method. When conducting this test, the owner of the vessel, in addition to the measures provided for by NP-044-03, must develop and implement additional measures safety depending on local test conditions.

The results of a hydraulic test are considered satisfactory if it is not found:

• - leaks, cracks, "tears" and "sweating" in the base metal, welded and riveted joints (during pneumatic testing - gas passes);
• - leaks in detachable connections;
• - residual deformations of vessel walls;
• - apparent pressure drop in the vessel on the manometer.

If defects are detected by the inspecting person, depending on their nature, a decision may be made to prohibit the operation of the vessel, put it into temporary operation, reduce the period of the next survey, reduce operating parameters, etc.

After completion of all repair work (before applying protective coatings and insulation), steam boilers are subjected to a hydraulic test and a steam test in the presence of the Surveyor to the Register.
Hydraulic tests are carried out under the condition that the boiler is completely filled with water and air is removed, with two sealed pressure gauges and at a temperature of water and ambient air of at least + 5 C. At the same time, the temperature difference between water and ambient air should exclude the possibility of sweating.
During the test, the pressure should not increase rapidly, it is forbidden to perform work on the ship that causes noise or knocking.
The hydraulic test is carried out in the following order: raising the pressure to the working pressure, preliminary inspection at the working pressure, raising the pressure to the test pressure with a holding time (with the pump turned off) for 10 minutes, lowering the pressure to the working pressure and inspection.
If during the hydraulic test knocks are heard in the boiler or other abnormal phenomena are noticed, the tests are interrupted and after the release of water, the boiler is carefully inspected to determine the location and nature of the damage. After the defect is eliminated, the test is repeated.
The boiler is recognized as serviceable if during the inspection no leaks, residual deformations, ruptures of seams and other signs of violation of the integrity of any parts and connections are found.
The steam sample of the boiler is carried out in combination with fittings, equipment, service mechanisms and pipelines, at operating pressure. At the same time, it is necessary to make sure that the water-indicating devices (water-gauge glasses, test taps, remote water level indicators, etc.) are in good condition, as well as the upper and lower blowing of the boiler. They check the condition of the fittings, the operation of the drives, the absence of steam, water, fuel leaks in glands, flanges and other connections.
Safety valves are tested in operation for operation. They must be adjusted to the following opening pressures: P open. less than 1.05Рр (at Рр less than 1.0 MPa); R open more than 1.03Рр (when Рр is more than 1.0 MPa), where Рр is the working pressure.
The maximum allowable opening pressure of the valve must not exceed 1.1 Pp. The safety valves of superheaters must be adjusted to operate with some advance of the boiler valves.
Check the operation of manual actuators for undermining safety valves. If the results are positive, they will be sealed by the Register inspector.
The operation of automatic control systems of the military-industrial complex is checked: the reliability and timeliness of the operation of signaling, protective and blocking devices (when the water level in the boiler drops below the permissible level, the air supply to the furnace is interrupted, the torch in the furnace is extinguished and in other cases provided for by the automation system).
Check the operation of the military-industrial complex during the transition from automatic to manual control and vice versa.
After the end of the steam test and the elimination of the identified defects, they begin to insulate the boiler. The surfaces of the boiler to be insulated, as well as the frame and casing, are cleaned and painted with red lead or AL 177 paint.
The insulating material is soaked in hot water and applied to hot insulated surfaces with a layer of 10-30 mm. After the first layer has dried, a second layer is applied, and so on, until insulation is obtained. desired thickness. The thickness of the insulation depends on the temperature of the working medium (for boilers - 60-100 mm).
As an insulating material for ship boilers, asbestos fluff, asbestos cloth, asbestos cardboard, asbestos cord, diatomite (diatomaceous earth), asbozurite (a mixture of asbestos with diatomite), sovelit and newvel - a mixture of magnesia MgO and magnesium oxide hydrate Mg (OH) 2 with asbestos.
To save expensive insulating materials (soverite, newel), insulation is made up of different materials. For example, the first layer - 10 mm - is applied from fluff asbestos, the second - 40-50 mm thick - from sovelite or nuvel, the third - 10 mm thick - from asbozurite.
Insulating materials applied to the surfaces of the boilers are fastened with a metal mesh and covered with a sheathing of galvanized roofing iron. Overlay steel bandages. The boilers are also insulated with mattresses made of asbestos fabric filled with sovelite or nuvel. The mattresses are sewn together with brass wire, laid on the insulated parts of the boiler, fitted with bandages and covered with a metal casing.
The walls of the combustion chamber and gas ducts of water-tube boilers are sheathed with removable shields made of thin steel sheets insulated with asbestos cardboard (or other insulating material) with a thickness of at least 10 mm. Asbestos is attached to the shields with bolts, and the shields are attached to the boiler frame on the battens. All joints of the boiler casing are made on asbestos gaskets, which ensures the gas-tightness of the casing.

MINISTRY OF ENERGY AND ELECTRIFICATION OF THE USSRPRODUCTION ASSOCIATION FOR ADJUSTMENT, IMPROVEMENT OF TECHNOLOGY AND OPERATION OF POWER PLANTS AND NETWORKS "SOYUZTEKHENERGO" GUIDELINES FOR TESTING THE HYDRAULIC STABILITY OF DIRECT-FLOW POWER WATER
SOYUZTEKHENERGO
Moscow 1989 Content DEVELOPED by the Moscow head enterprise of the Production Association for the adjustment, improvement of technology and operation of power plants and networks "Soyuztekhenergo" PERFORMERS V.M. LEVINZON, I.M. GIPSHMAN APPROVED by "Soyuztechenergo" 05.04.88 Chief Engineer K.V. SHAHSUVAROV Expiry date set
from 01.01.89
until 01.01.94. These Guidelines apply to stationary once-through steam power boilers and hot water boilers with absolute pressure from 1.0 to 25.0 MPa (from 10 to 255 kgf / cm 2). Guidelines do not apply to boilers: with natural circulation; steam-heating; locomobile installations; waste heat boilers; energy technology, as well as other special-purpose boilers. Based on the experience gained in Soyuztekhenergo and related organizations, methods for testing boilers in stationary and transient modes are specified and described in detail in order to check the conditions hydraulic stability of steam-generating heating surfaces of once-through steam boilers or screen and convective heating surfaces of hot water boilers. Hydraulic stability tests are carried out both for newly created (head) boilers and for those in operation. The tests allow you to check the compliance of the hydraulic characteristics with the calculated ones, evaluate the influence of operational factors and determine the boundaries of hydraulic stability. technology and operation of power plants and networks", approved by Order of the Minister of Energy and Electrification of the USSR No. 313 dated 03.10.83. Methodological instructions can also be used by other commissioning organizations that perform tests of the hydraulic stability of once-through boilers.

1. MAIN INDICATORS

1.1. Definition of hydraulic stability: 1.1.1. The following indicators of hydraulic stability are subject to determination: thermal-hydraulic sweep; aperiodic stability; pulsation stability; motion stagnation. 1.1.2. The thermal-hydraulic scan is determined by the difference in the flow rates of the medium in individual parallel elements of the circuit and the outlet temperatures in the same elements compared to the average values ​​in the circuit. 1.1.3. Violation of aperiodic stability associated with the ambiguity of hydraulic characteristics is determined: by an abrupt decrease in the flow rate of the medium in individual elements of the circuit (at a rate of 10%/min or more) with a simultaneous increase in the outlet temperature in the same elements compared to the average values ​​in the circuit; or when the movement is reversed by changing the sign of the flow rate of the medium in individual elements to the opposite, with an increase in temperature at the inlet to these elements. On boilers operating with subcritical pressure in the duct, an increase in temperature at the outlet of the elements may not be observed. 1.1.4. Violation of pulsation stability is determined by pulsations of the flow rate of the medium (as well as temperatures) in parallel elements of the circuit with a constant period (10 s or more), regardless of the amplitude of the pulsations. Flow fluctuations are accompanied by fluctuations in the temperature of the pipe metal in the heated zone and the temperature at the outlet of the elements (at subcritical pressure, the latter may not be observed). 1.1.5. The stagnation of movement is determined by the decrease in the flow rate of the medium (or the pressure drop on the flow measuring devices) in individual elements of the circuit to zero or to values ​​close to zero (less than 30% of the average flow rate). 1.1.6. It is allowed in cases provided for by the normative method of hydraulic calculation [1], when violations of the hydraulic stability of one or another type are obviously impossible, not to determine the corresponding indicators. So, for example, it is not required to check the aperiodic stability with a purely lifting movement in the circuit. The pulsation stability test is not required at supercritical pressure, if there is no subcooling to boiling at the inlet, and also for hot water boilers. At supercritical pressure, most circuits do not require a check for stagnation, except in some cases (heavily slagging rising furnace screens, shaded corner pipes, etc.). 1.1.7. The following indicators are also subject to determination, which are required to assess the conditions and boundaries of hydraulic stability: flow rate and average mass velocity of the medium in the circuit, G kg/s and wr kg / (m 2 × s); medium temperature at the inlet and outlet of the circuit, tinx and tyoux °C; Maximum temperature at the exit of the contour elements, °C; subcooling to boiling point, D tunder ° С (for hot water boilers); medium pressure at the outlet of the circuit (or at the inlet to the circuit, or at the end of the evaporation part of the steam boiler), for hot water boilers - at the inlet and outlet of the boiler, R MPa; flow rate and mass velocity of the medium in the contour elements, Gemail kg/s and ( wr)email kg / (m 2 × s); heat absorption (enthalpy increment) in the circuit, D i kDk/kg; metal temperature of individual pipes in the heated area, tvtn ° C. 1.1.8. When determining individual (from among those specified in paragraph 1.1.1) indicators of hydraulic stability or during tests of a research nature, additional indicators can also serve as: pressure drop in the circuit (from inlet to outlet), D R to kPa; temperature at the inlet to the circuit elements, temail° C; thermal sweep coefficients, rq; hydraulic sweep, rq; uneven heat perception, hT. 1.2. In necessary cases (for new or reconstructed circuits, during a preliminary assessment of stability, to clarify the type, nature and causes of violations detected, etc.), the hydraulic characteristics of the corresponding circuits are calculated or the reliability margins are assessed according to factory calculations. The calculation of hydraulic characteristics is carried out on an electronic computer (according to the programs developed at Soyuztechenergo) or manually according to [1]. Based on the calculated data and a preliminary assessment of the hydraulic stability of individual circuits, the least reliable of them are more fully equipped with measuring instruments, the tasks and the test program are specified.

2. INDICATORS OF THE ACCURACY OF DETERMINED PARAMETERS

The indicators of thermal and hydraulic operation of the circuit are determined by measurements of temperature, flow and pressure in the circuit and its elements. The error of these indicators, obtained as a result of processing measurement data, should not exceed the values ​​\u200b\u200bspecified in Table. 1. Table 1

Name

Error

steam boilers

Hot water boilers

Consumption and average mass velocity of the medium in the circuit, %

Temperature at the inlet and outlet of the circuit, °C

Temperature at the inlet and outlet of the circuit elements, °С

Subheating to boiling point, °С

Pressure at the inlet and outlet of the circuit, %

Pressure drop in the circuit (from inlet to outlet), %

Note. The flow rate of the medium in the elements of the contour, the increment of enthalpy, as well as the coefficients of thermal and hydraulic scanning and uneven heat absorption, are determined without accuracy rationing. The temperature of the metal in the heated zone is determined without accuracy standardization according to the guidelines for departmental full-scale tests of the temperature regime of the screen heating surfaces of steam and hot water boilers.

3. TEST METHOD

3.1. The available regulatory materials, first of all [1], make it possible to perform an approximate calculation of the main indicators of the hydraulic stability of the boiler. The calculations include, however, a number of parameters and coefficients that can be established with the required accuracy only empirically, including: actual temperatures environment along the path; enthalpy increment in the loop, pressure, pressure difference (loop resistance); temperature distribution by elements; values ​​of parameter deviations in dynamic modes of real operation; coefficients of thermal, hydraulic sweep and uneven heat absorption, etc. On the other hand, calculation methods cannot cover the whole variety of specific constructive solutions used in boilers, especially in newly created ones. In view of this, full-scale industrial tests are the main method for determining the hydraulic stability of steam and hot water boilers. 3.2. Depending on the purpose of the work and the required scope of measurements, tests according to the Price List for experimental adjustment work and work to improve the technology and operation of power plants and networks are carried out in two categories of complexity: 1 - verification of the existing or newly developed calculation and testing methods; or identifying the operating conditions of new, not yet tested in practice, hydraulic circuits; or checking on the prototype of the heating surfaces of the boiler; 2 - testing of one heating surface of the boiler. 3.3. Tests are carried out in stationary and transient modes; in the operational or extended range of boiler loads; if necessary - also in kindling modes. In addition to planned experiments, observations are carried out in operational modes. 3.4. The definition of hydraulic stability indicators is carried out for the following types of hydraulic circuits of the boiler: tube packages and panels with parallel-connected heated pipes, inlet and outlet manifolds; heating surfaces with parallel-connected tube bundles or panels, inlet and outlet pipelines, inlet and outlet common headers; complex circuits with parallel subflows, which include heating surfaces, connecting pipelines, cross bridges and other elements. 3.5. In two-flow boilers, subject to a symmetrical design, it is allowed to perform tests for only one regulated flow with control of the regime parameters for both flows and for the boiler as a whole.

4. SCHEME OF MEASUREMENTS

4.1. The experimental control scheme includes special experimental measurements that provide experimental values ​​of temperatures, flow rates, pressures, pressure drops in accordance with the test tasks. Measuring instruments for experimental control are installed on both or on one regulated flow of the boiler (see clause 3.5). Measuring instruments of standard control are also used. 4.2. The scope of the experimental control includes measurements of the following main parameters: - the temperature of the medium along the steam-water path (for both streams), at the inlet and outlet of all successively connected heating surfaces in the economizer-evaporative part of the path (up to the built-in valve, separator, etc.), as well as in the superheating part and in the reheating path (before and after the injections and at the outlet of the boiler). For this purpose, submersible thermoelectric converters (thermocouples) of experimental control are installed, or regular funds measurements. Measuring instruments for experimental control are installed in the test surface. The boiler is equally equipped with measuring instruments along the steam-water path even if the tests cover only one or two heating surfaces. Without this, it is impossible to properly determine the influence of regime factors; - temperatures of the medium at the outlet (and, if necessary, also at the inlet) of subflows and individual panels in the contour (surface) under study. Measuring instruments are installed in the outlet pipes (immersion thermocouples; surface thermocouples are allowed with careful isolation of their installation sites). They cover all parallel elements. With a large number of parallel panels, it is allowed to equip some of them, including medium and most non-identical ones (in design and heating); - temperatures at the outlet of the coils (heated pipes) of the tested surfaces; in necessary cases (in case of danger of overturning, stagnation of traffic) - also at the entrance. This is the most massive type of measurement in terms of quantity. Measuring instruments are installed in the unheated zone of the coils (surface thermocouples); as a rule, in the same panels where outlet temperature measurements are provided. In multi-pipe panels, thermocouples are installed in "medium" pipes evenly in width (with a step of several pipes) and in pipes with thermal and structural non-identity (extreme and adjacent to them; envelope burners; differing in connection to collectors, etc.). in the coils of the tested surface of the unheated zone (as is the case, for example, on hot water boilers, according to their design), immersion thermocouples are installed to directly measure the temperature of the water at the outlet of these coils; - feed water flow rate along the steam-water path streams (one stream is allowed if the experimental control is set on one stream). The measuring device is usually a regular standard diaphragm in the supply line, to which, in parallel to the standard water meter, an experimental control sensor is connected; - the flow rate and mass velocity of the medium at the inlet to the subflows of the circuit (into each) and in the panel (selectively). TsKTI or VTI pressure pipes are installed on the supply pipes in panels, according to a preliminary assessment of the most dangerous in case of violations of hydrodynamics, and in coordination with the installation of thermocouples; - flow rate and mass velocity of the medium at the inlet to the coils. TsKTI or VTI pressure pipes are installed at the inlet sections of pipes in the unheated zone. The number and placement of measuring instruments is determined by specific conditions, including "medium" and the most dangerous coils, in accordance with the installation of thermocouples at the outlet of the coils, as well as temperature inserts (ie, on the same coils). Means for measuring flow rates in the elements of the circuit must be placed in such a way that they together, with the minimum possible number, reflect all the violations of stability expected in the circuit according to a preliminary assessment; - pressure in the steam-water path. Sampling devices for measuring pressure are installed at characteristic points of the path, including at the outlet of the tested surface, at the end of the evaporative part (before the built-in damper); for a hot water boiler - at the boiler outlet (as well as at the inlet); - pressure drop (hydraulic resistance) of a subflow, or a heating surface, or a separate section of the circuit under test. Selective devices for measuring pressure drop are installed in special cases: during tests of a research nature, when checking the compliance of calculated data with actual ones, in case of difficulties in classifying stability violations, etc.; - pipe metal temperature in the heated zone. Temperature or radiometric inserts for measuring metal temperature are installed in the tested surfaces, mostly in the flow, where there is the bulk of the measurements, but also control inserts in other flows. The inserts are placed along the perimeter and along the height of the furnace in the area of ​​maximum heat stresses and the expected maximum metal temperatures. The choice of pipes for installing inserts should be linked to the installation of temperature and flow measurements on the coils. 4.3. Measuring instruments for experimental control according to clause 4.2 refer to purely once-through boiler circuits. In complex branched hydraulic circuits inherent in modern boilers, other necessary measuring instruments are installed in accordance with the specific design features. For example: a circuit with parallel subflows and a transverse hydrodynamic dam - temperature measurement upstream of the dam and behind it on both subflows; measurement of flow through the jumper; measurement of pressure difference at the ends of the bulkhead; boiler with medium recirculation through a screen system (pump or non-pump) - measurement of the medium temperature in the recirculation circuit outlets upstream and downstream of the mixer; measurement of the medium flow rate in the recirculation circuit outlets and through the screen system (behind the mixer); measurement of pressures (pressure drops) at the nodal points of the contour, etc. 4.4. The performance indicators of the boiler as a whole, the indicators of the combustion mode, as well as the general block indicators, are recorded using standard control devices. 4.5. The volume, as well as the features of the measurement scheme, are determined by the goals and objectives of the tests, the category of complexity, the steam output and parameters of the boiler, the design of the boiler and the circuit under test (radiation or convective surfaces, all-welded and smooth-tube screens, type of fuel, etc.). So, for example, when testing the NFC on a gas-oil boiler of a 300 MW monoblock, the measurement scheme can include from 100 to 200 temperature measurements in the unheated zone, 10-20 temperature inserts, about 10 flow and pressure measurements; when testing a hot water boiler - from 50 to 75 temperature measurements, 5-8 temperature inserts, approximately 5 flow and pressure measurements. 4.6. All measurements of experimental control are mandatory submitted for registration by means of self-recording secondary devices. Secondary devices are placed on the experimental control panel. 4.7. The list of measurements, their locations on the boiler and breakdown by instruments are given in the documentation for the measurement scheme. The documentation also includes a circuit for switching devices, a sketch of a shield, a layout for temperature inserts, etc. Exemplary measurement schemes, in relation to testing the NGMP-314 boiler and testing the KVGM-100 hot water boiler, are shown in fig. 12.
Rice. 1. Scheme of experimental control of NGMP boiler TGMP-314:
1-3 - panel numbers; I-IV - numbers of moves; - immersion thermocouple; - surface thermocouple; - temperature insert; - pressure pipe TsKTI; - selection of pressure; - selection of differential pressure.
The number of surface thermocouples: at the inlet of the coils of the front semi-flow A: I stroke - 16; II move - 12; III move - 18; the same rear semi-flow A: I stroke - 12; II move - 8; III - move - 8; IV move - 8 pcs.; on jumper A - 6 pcs.; on jumper B - 4 pcs. . Notes: 1 . The diagram shows measurements along flow A. Immersion thermocouples are installed along flow B similarly to flow A. 2. Measurements along flow B are similar to flow A. 3. The numbering of panels and coils is from the axes of the boiler. 4. Measurements of temperatures and flow rates in the steam-water path are carried out in accordance with the scheme of instrumentation and A of the boiler. Rice. 2. Scheme of experimental control of the hot water boiler KVGM-100:
- upper collector; - lower manifold; - surface thermocouples on pipelines; - the same on pipes and risers; - immersion thermocouples in envelope coils; - temperature inserts at the mark of the upper tier of burners; - selection of differential pressure;
1 - rear screen of the convective part: 2 - side screen of the convective part; 3 - screens of the convective part; 4 - package I; 5 - packages II, III; 6 - intermediate screen of the furnace; 7 - side screen of the firebox; 8 - front screen

5. TESTING TOOLS

5.1. When testing, standardized measuring instruments should be used, metrologically provided in accordance with GOST 8.002-86 and GOST 8.513-84. Types and characteristics of measuring instruments are selected in each specific case depending on the equipment under test, the required accuracy, mounting and installation conditions, ambient temperature and from other external influencing factors. The measuring instruments used in the tests must have valid verification marks and technical documentation, indicating their suitability, and ensure the required accuracy. 5.2. Requirements for measurement accuracy: 5.2.1. The permissible error in measuring the initial values, which ensures the required accuracy of the determined indicators (see section 2), should not exceed for: the temperature of water, steam, metal in the unheated zone: steam boiler - 10 ° C; hot water boiler - 5 ° C; water flow and steam - 5%; pressure of water and steam - 2%. 5.2.2. The requirements specified in this section refer to type tests of boilers. When testing on experimental, or modernized, or fundamentally new equipment, or when checking new test methods, the test program should stipulate Additional requirements to measuring instruments and to accuracy characteristics. 5.3. Indicators can be used to measure parameters that do not require standardization of accuracy during testing (see Section 2). The specific types of indicators used are specified in the test program. 5.4. Temperature measurement: 5.4.1. The temperature is measured using thermoelectric converters (thermocouples). When measuring at a relatively low temperature level requiring high accuracy, thermoelectric thermometers (resistance thermometers) according to GOST 6651-84 can also be used. (400-600°С) wire diameter 1.2 or 0.7 mm. It is recommended to insulate thermionic wires with silica or quartz thread by double winding. Detailed characteristics of thermocouples are contained in special literature [2, etc.]. 5.4.2. For direct measurement of water and steam temperatures, standard TXA type immersion thermocouples are used. Immersion thermocouples are installed on a straight section of the pipeline in a sleeve welded into the pipeline. The length of the element is selected depending on the diameter of the pipeline based on the location of the working end of the thermocouple of the element along the flow axis. The minimum length of a standard element is 120 mm. In pipelines of small diameter, immersion thermocouples of non-standard manufacture can be installed, but in compliance with the installation rules (for example, when testing hot water boilers, see clause 4.2.3). 5.4.3. Surface thermocouples are installed outside the heating zone at the outlet (or inlet) sections of the coils, near the collector, as well as on the outlet (or inlet) pipes of the panels. The connection with the metal of the pipe (the working end of the thermocouple) is recommended to be made by caulking the thermoelectrodes into a metal boss (separately into two holes), which, in turn, is welded to the pipe. The working end of the thermocouple can also be made by caulking the thermocouple into the body of the pipe. The initial section of the insulated surface thermocouple, at least 50-100 mm long from its working end, must be tightly pressed against the pipe. The location of the thermocouple and the pipeline in this area must be carefully covered with thermal insulation. 5.4.4. Temperature measurement of pipe metal in the heated area (by means of Soyuztekhenergo temperature inserts with a KTMS thermocouple cable or XA thermocouples, or TsKTI radiometric inserts with XA thermocouples) should be carried out in accordance with the "Guidelines for departmental full-scale tests of the temperature regime of screen heating surfaces of steam and hot water boilers." Inserts are not standardized measuring instruments and serve as indicators during hydraulic stability tests (see clause 5.3). 5.4.5. Self-recording electronic multipoint potentiometers with an analog, digital or other form of recording (continuous or with a registration frequency of no more than 120 s) are used as secondary devices for measuring temperature by means of thermocouples. In particular, KSP-4 devices with an accuracy class of 0.5 by 12 points (with a cycle of 4 s and a recommended tape speed of 600 mm / h) are commonly used. Multi-channel measuring devices with access to digital printing and punching devices are also used. As secondary devices for temperature measurements with resistance thermometers, DC measuring bridges are used. 5.5. Measurement of water and steam flow: 5.5.1. The flow is measured by means of flowmeters with constriction devices (measuring orifices, nozzles) in accordance with the "Rules for measuring the flow of gases and liquids by standard constriction devices" RD 50-213-80. Flowmeters with orifices are installed on pipelines with a single-phase medium with an internal diameter of at least 50 mm. The flow measuring device, its installation and connecting (impulse) lines must comply with the specified rules. 5.5.2. In cases where additional pressure losses are not allowed, as well as on pipelines with an internal diameter of less than 50 mm, flow meters with pressure tubes (Pitot tubes) designed by TsKTI or VTI are installed as a flow indicator [2]. Rod tubes of TsKTI, as well as round tubes of VTI, have a small non-recoverable pressure loss. Pressure tubes are suitable only for the flow of a single-phase medium. The design of pressure tubes TsKTI and VTI with a description and flow coefficients is given in Appendix 1 and in fig. 3, 4. Rice. 3. Designs of pressure tubes for measuring water circulation rates
Rice. 4. Values ​​of flow coefficients for rod and cylindrical tubes 5.5.3. Differential pressure gauges (GOST 22520-85) are used as primary transducers (sensors) for flow measurement. Connecting lines are laid from the measuring device to the sensor in accordance with the rules of RD 50-213-80. 5.6. Static pressure signals are sampled through openings (fittings) in pipelines or collectors of the heating surface outside the heating zone. Selective devices should be installed in places protected from the dynamic impact of the work flow. Pressure gauges with electric output (GOST 22520-85) are used as sensors. 5.7. Differential pressure measurement is carried out using sampling static pressure at the beginning and at the end of the measured section of the circuit, which are performed according to the type of pressure measurement. Differential pressure gauges are used as sensors. 5.8. The type and accuracy class of sensors and secondary instruments used in measuring flow, pressure drop and pressure are given in Table. 2. Table 2 Note. To measure flow, instead of DME and Sapphire 22-DTS sensors, which give a linear signal of differential pressure, DMER and Sapphire 22-DTS sensors with NIR (with a square root extraction unit and transition to the flow rate scale) can be used. Since the scales during testing are usually non-standard and must be suitable for various conditions, sets with a linear scale of differences (with further recalculation during processing) are often more convenient. 5.9. Choice sensors according to the pressure drop measurement range is made from a range of values ​​according to GOST 22520-85. Approximately used values: consumption feed water- 63; 100; 160 kPa (0.63; 1.0; 1.6 kgf / cm 2); consumption (speed) of water in panels and coils - 1.6; 2.5; 4.0; 6.3 kPa (160; 250; 400; 630 kgf / cm 2); for boilers SKD-40 MPa (400 kgf / cm 2), for boilers VD-16; 25 MPa (160; 250 kgf / cm 2); for hot water boilers - 1.6; 2.5 MPa (16; 25 kgf / cm 2). 5.10. The lower guaranteed measurement limit for flow sensors (LMWR) is 30% of the upper limit. In cases where it is required to cover a large range of flow rates (or pressures) during testing, including small and ignition loads of the boiler, two sensors are connected in parallel to the measuring device for different measurement limits, each with its own secondary instrument. 5.11. To fix the main values ​​of flow and pressure, usually single-point secondary devices with continuous recording (with a recommended tape speed of 600 mm/h) are used. Continuous recording is necessary due to high speed flow of hydrodynamic processes, especially in case of stability violations. If there are a large number of the same type of hydraulic sensors in the circuit (for example, for measuring speeds in panels and coils), some of them can be taken out to multi-point secondary devices indicated in Table. 2 (for 6 or 12 points with a cycle of no more than 4 s). 5.12. The experimental control board is mounted near the control room (preferably), or in the boiler room (at the service mark if there is good communication with the control room). The shield is equipped with electric power, lighting, locks. 5.13. Materials: 5.13.1. The quantity and range of materials required for the installation of connecting electrical and pipe wiring, as well as electrical and thermal insulation materials, is determined in the test program or in the custom specification, depending on the steam or heat output of the boiler, its design and the scope of measurements. 5.13.2. Primary switching of temperature measuring instruments to prefabricated boxes (SC) is carried out: from immersion thermocouples and temperature inserts with a compensating wire (copper-constantan for XA thermocouples, chromel-copel for XK thermocouples); from surface thermocouples with a thermocouple wire. Secondary switching from the SC to the experimental control board is carried out with a multi-core cable (preferably compensating, in the absence of such - copper or aluminum). In the latter case, to compensate for the temperature of the free end of the measuring thermocouples, a so-called compensation thermocouple is thrown from the SC to the device. 5.13.3. The switching of signals for flow and pressure from the sampling point to the sensor is carried out by connecting tubes (made of steel 20 or 12Kh1MF) with shut-off valves d y 10 mm for the corresponding pressure. The electrical connection between the sensor and the switchboard is made with a four-wire cable (screened if there is a risk of interference).

6. TEST CONDITIONS

6.1. Tests are carried out in stationary modes of the boiler, in transient modes (with mode disturbances, lowering and raising the load), and, if necessary, in kindling modes. 6.2. When conducting tests in stationary modes, the ones indicated in Table. 3 limit deviations from the average operational values ​​of the boiler operation parameters, which are controlled by verified standard instruments. Table 3

Name

Limit deviations, %

Steam boilers with steam output, t/h

Hot water boilers

Steam output

Feed water consumption

Pressure

Superheated steam temperature (primary and intermediate)

Water temperature (boiler inlet and outlet)

The boiler load must not exceed the set maximum steam output (or heating output). The final temperature of the superheated steam (or the temperature of the water at the outlet of the boiler) and the pressure of the medium should not be higher than those specified in the manufacturer's instructions. 2 hours. Between experiments should be provided sufficient time for restructuring and stabilization of the regime (on gas and fuel oil - at least 30-40 minutes, on solid fuel - 1 hour). With several types of fuel burned, as well as depending on the external contamination of the heating surfaces of the boiler and other local conditions, the experiments are divided into series conducted at different times.6.3. When testing in transient modes, the effect of organized mode disturbances on the hydraulic stability is checked. The operating parameters of the boiler must be maintained within the limits stipulated by the test program.6.4. During the tests, the fuel must be supplied to the boiler, the quality of which is provided for by the test program.

7. PREPARATION FOR TESTS

7.1. The scope of work in preparation for testing includes: familiarization with the technical documentation for the boiler and the power unit, the condition of the equipment, operating modes; drawing up and agreeing on a test program; development of an experimental control scheme and technical documentation for it; technical supervision of the installation of an experimental control scheme; adjustment of the scheme experimental control and putting it into operation. 7.2. The composition of the technical documentation that requires familiarization includes, first of all: drawings of the boiler and its elements; schemes of steam-water and gas-air paths, instrumentation and automation; boiler calculations: thermal, hydraulic, thermomechanical, wall temperature, hydraulic characteristics (if any); boiler operation manual, regime card; documentation on pipe damage, etc. On-site familiarization with the equipment of the boiler and the dust preparation system, with the power unit as a whole, with standard instrumentation is carried out. The operational features of the equipment to be tested are revealed. 7.3. A test program is drawn up, which should indicate the purpose, conditions and organization of the experiments, the requirements for the state of the boiler, the necessary parameters of the boiler, the number and main characteristics of the experiments, their duration, calendar dates. The used non-standardized measuring instruments are indicated. The program is coordinated with the heads of the relevant departments of the TPP (KGTs, TsNII, TsTAI) and approved by the chief engineer of the TPP or REU. , in power systems, thermal and electric networks", approved by the USSR Ministry of Energy on 14.08.86. 7.4. The content of the experimental control scheme is given in Sec. 4. In a number of cases, with a large amount of testing, a technical assignment is drawn up for a draft experimental control scheme, according to which a specialized organization or subdivision develops a scheme. With a small volume, the scheme is drawn up directly by the team conducting the tests. 7.5. On the basis of the experimental control scheme, documentation on preparatory work for testing is compiled and transferred to the customer: a list of preparatory work (in which it is advisable to indicate the amount of installation work performed directly on the boiler); specification for the necessary instruments and materials supplied by the customer; sketches of fixtures that require manufacturing ( temperature inserts, bosses, shield panels, etc. ).A specification is also being drawn up for devices and materials supplied by Soyuztekhenergo. Appendix 2 provides exemplary examples of this documentation. 7.6. Installation supervision: 7.6.1. Before starting the installation, the marking of the installation sites of the measuring devices is carried out, as well as the choice of places for the SC, shield, sensor stands. The markup must be treated with special attention as an operation that determines the quality of subsequent measurements. When installing test tools, it is necessary to check the correct installation of measuring devices and compliance with the drawings. 7.6.2. Welding of the bosses of surface thermocouples is carried out under the direct supervision of the representatives of the brigade. The main thing in this case is to prevent the wire from burning (welding with electrodes of 2-3 mm, with a minimum current), and in case of a burn, restore it again. It is recommended to check the presence of the chain immediately after welding. 7.6.3. The laying of thermocouple and compensating wires to the SC is carried out in protective pipes. Open laying with a tourniquet is allowed in some cases for a short time, but is not recommended. Laying should be carried out with a solid wire, avoiding intermediate connections. Particular attention should be paid to possible places of damage to the insulation of wires (bends, turns, fasteners, entry into protective pipes, etc.), protecting them with additional reinforced insulation. To exclude possible EMF pickups, compensating wires and cables should not intersect with routes power cables. 7.6.4. Pressure pipes are installed on straight sections of pipes, away from bends and collectors. The straight section of flow stabilization in front of the tube should be (20 ¸ 30) D (D - inner diameter of the pipe), but not less than 5 D. Pressure tube immersion is 1/2 or 1/3 D. The tube must be welded with signal-receiving holes strictly along the center line of the pipe; selective fittings are located horizontally. The main valves must be accessible for service. 7.6.5. The laying of connecting lines for measuring flow and pressure must meet the requirements of RD 50-213-80. When laying connecting pipes, one-sided slope or horizontal lines must be strictly observed; do not allow the passage of connecting pipes in places with high temperature in order to prevent boiling or heating of still water in them. 7.6.6. Sensors for measuring flow and differential pressure are installed below (or at the level of) measuring devices, usually at zero and service marks. Sensors are mounted on group stands. For normal maintenance, devices are provided for purging the sensors (moreover, two shut-off valves are installed on each purge line to avoid leaks). A complete set for one sensor is 9 shut-off valves(radical, in front of the sensor, purge and one equalizing). 7.6.7. Before installing the sensors on the stand, they should be carefully checked in the metrological service of the TPP and calibrated. After installation on the stands, it is necessary to check the position of "zeros" and the maximum values ​​of the drops. For sensors designed to measure water flow in panels and coils, it is advisable to shift the "zero" on the scale of the secondary device by 10-20% to the right (in case of zero or negative values ​​in non-stationary modes). In any special occasions, when it is possible to move the flow in both directions, the "zero" of the device is set to 50%, i.e. to the middle of the scale (for example, flow reversal, strong pulsation, hydrodynamic jumper tests, etc.). When zero is offset, the instrument is used as an indicator. 7.7. Upon completion of the preparatory installation work, the experimental control circuit is adjusted (diagnostic switching, pressure testing and trial switching on of sensors, switching on and debugging of secondary devices, detection and elimination of defects). 7.8. Before testing, the readiness of the boiler and its elements for testing should be checked (gas tightness, internal and external contamination of heating surfaces, density and serviceability of fittings, etc.). Particular attention is paid to regular instrumentation: the serviceability of the measuring instruments necessary for testing, the correctness of their readings, the presence of valid verification marks (for water meters and other instruments), the compliance of experimental and standard instruments. The condition of the boiler must meet the requirements specified in the test program.

8. TESTING

8.1. Working program of experiments: 8.1.1. Before the start of the tests, on the basis of the approved test program, working programs of experiments are drawn up and agreed with the management of the TPP. The work program is drawn up for a separate experiment or for a series of experiments. It contains instructions on the organization of the experiment, on the state of the equipment participating in the experiment, the values ​​of the main parameters and the permissible limits of their deviations, and a description of the sequence of operations performed. 8.1.2. The work program is approved by the chief engineer of the TPP and is mandatory for the personnel. 8.1.3. For the duration of the experiment, a responsible representative from the TPP should be allocated, who provides operational management of the experiment. The test manager from Soyuztechenergo provides technical guidance. The shift personnel perform all their actions during the experiment on the instructions (or with the knowledge) of the test manager, transmitted through the responsible representative of the TPP. Appendix 3 provides an approximate working program of the experiments. 8.2. During the entire time of the experiment, compliance with the work program of the following values ​​must be ensured: excess air; shares of flue gas recirculation; fuel consumption; flow rate and temperature of feed water; medium pressure behind the boiler; steam consumption (only for a steam boiler); temperature of fresh steam (or water) behind the boiler; furnace mode; mode of operation of the dust preparation system. 8.3. In case of non-compliance of the boiler operation parameters with the requirements established in sec. 6 and in the working program, the experience stops. The experiment is also terminated in the event of an emergency at the power unit (or at the power plant). In the event that the temperature limits of the medium and metal specified in the program are reached, or the flow of the medium in individual elements of the boiler ceases (or sharply decreases), or other violations of hydrodynamics appear according to the experimental control devices, the boiler is switched to a mode easier for the equipment (previously introduced indignation or necessary decisions are made). If violations do not pose an immediate danger, the test may continue without further tightening of the regime being tested. 8.4. Tests begin with preliminary experiments. In the course of preliminary experiments, familiarization with the operation of the equipment and features operating conditions, final debugging of the measurement scheme, working out the organizational routine in the brigade and relationships with the shift personnel. 8.5. Stationary modes: 8.5.1. Tests in stationary modes include experiments: at the rated load of the boiler; two or three intermediate loads (usually at 70% and 50% loads as per factory calculations, as well as at the load prevailing in the operating conditions); minimum load (established in operation or agreed for testing). For steam boilers, experiments are also carried out with a reduced feed water temperature (with the HPH turned off). For hot water boilers, experiments are also carried out: different temperature inlet water; with minimum outlet pressure; with the minimum allowable water flow. Static characteristics (depending on the boiler load) of temperatures and pressures along the path are determined; indicators of hydraulic stability of the tested circuits in stationary modes; allowable load range of the boiler according to these indicators. 8.5.2. In stationary experiments, the regime according to the operational regime map is taken as the basis. The influence of the main regime factors (excess air, DRG loading, various combinations of operating burners or mills, fuel oil illumination, feed water temperature, boiler slagging, etc.) is also checked. 8.5.3. On boilers operating on two types of fuel, experiments are carried out on both types (on reserve fuel and on a mixture of fuels is allowed in a reduced volume). On dust-gas boilers, experiments on natural gas should be carried out after a sufficiently long continuous campaign on gas according to the condition of contamination of the screens. On slagging fuels, if necessary, experiments are carried out at the beginning and at the end of campaigns, on a "clean" and on a slagged boiler. 8.5.4. For SKD boilers operating on sliding pressure, hydraulic stability tests should be carried out taking into account the guidelines for testing once-through boilers in unloading modes at the sliding pressure of the medium. 8.5.5. At a given load of the boiler, in order to obtain more reliable experimental data, two duplicate experiments should be carried out, and not on the same day (preferably with a break in time). If necessary, additional control experiments are carried out. 8.5.6. Tests in stationary modes should precede experiments with disturbances. 8.6. Transitional modes: 8.6.1. The most unfavorable in terms of hydraulic stability of boiler circuits are, as a rule, non-stationary conditions associated with mode disturbances and certain deviations of parameters from normal (average) conditions. In experiments in transient conditions, the hydraulic stability of the tested circuits is determined in experimental conditions close to emergency, with an imbalance in the ratio of "water-fuel" and with thermal distortions. The maximum reduction in flow rates and temperature increase in the elements of the contour, the discrepancy between individual elements, as well as the nature of the restoration of the initial values ​​after the removal of the disturbance are controlled. 8.6.2. For steam boilers, the following mode disturbances are checked: a sharp increase in fuel consumption; a sharp decrease in feed water consumption; shutdown of individual burners while maintaining the total fuel consumption (the effect of thermal skew across the width and depth of the furnace); as well as other actions due to local circumstances (turning on blowers, switching to another fuel, etc.). Depending on the circuit layout, sometimes it may also be necessary to check the combination of unbalance with skew (for example, water discharge when the burners are turned off). For hot water boilers, mode disturbances are checked a sharp decrease in feed water consumption and a decrease in medium pressure, etc. 8.6.3. The value and duration of disturbances are not standardized and are established on the basis of existing experience and real operating conditions depending on the design of the boiler, its dynamic characteristics, type of fuel, etc. % and a duration of 10 minutes (i.e., according to existing experience, almost until the parameters along the path are stabilized). With large disturbances (20-30%), according to the condition of maintaining the overheating temperature, the duration is usually less than 3-5 min without stabilization of the parameters, which does not give confidence in identifying all the features of the hydrodynamics of the circuit. Disturbances less than 15% have a relatively weak effect on the steam-water path. 8.6.4. Disturbances can be made on both or only on one regulated flow of the steam-water path (or one side of the boiler) for which the test is being performed. 8.6.5. Before applying disturbances, the boiler must operate in a stationary mode for at least 0.5-1.0 hours until the parameters stabilize. 8.6.6. Experiments with mode disturbances are carried out at two or three boiler loads (including the minimum one). Usually they are combined with experiments at the required load in a stationary mode and are carried out at the end of such. 8.7. If necessary (for example new technology kindling, damage in start-up modes, fearful results of preliminary calculations, etc.), the hydraulic stability indicators of the tested circuit are checked in the modes of boiler kindling. Kindling is carried out in accordance with the operating instructions and the work program. 8.8. During the experiment, continuous monitoring of the operation of the boiler and its elements is carried out using standard and experimental control devices. It is necessary to constantly monitor the measurements of experimental control and timely detect certain violations of hydrodynamics. Identification of violations of hydrodynamics is the main task of testing. 8.9. An operational log is maintained with a fixation of the progress of experience, operations performed by watch personnel, the main indicators of the regime and disturbances. Regular entries are made in the observation logs of the boiler parameters using standard instruments. The frequency of recording is 10-15 minutes in stationary modes, 2 minutes with disturbances. Excess air is controlled (according to oxygen meters or Orsa devices). It is necessary to monitor the combustion mode by inspecting the furnace. 8.10. Careful supervision is carried out over the serviceability of the experimental control instruments, including: the "zero" position, the position and pull of the tape, the clarity of the end of the readings on the tape, the correctness of the readings of the instruments and individual points. Faults must be repaired immediately. The conformity of the readings of the experimental and standard instruments according to similar parameters* is checked. Before each experiment, the registration and setting of the "zeros" of the flow and pressure sensors is carried out. At the end of the experiment, the registration of "zeros" is repeated. * The difference in readings should not exceed , where and 1 and and 2 - instrument accuracy classes. 8.11. Regularly at the beginning, end and throughout the experiment, simultaneous time marks are made on all tapes to synchronize the readings of the instruments. The mark is made manually or with a large number of devices using a special electrical circuit for marking the time (simultaneous shorting of the circuits of the devices). 8.12. The obtained experimental material is recommended, if possible, to be subjected to express processing immediately after the experiments. Preliminary analysis of the results of previous experiments makes it possible to more purposefully conduct subsequent experiments with timely adjustment of the test program, if necessary. 8.13. During the testing period, in addition to planned experiments, observations are made of the operating modes of the boiler using standard and experimental control devices. The purpose of the observations is to obtain confirmation of the representativeness and completeness of the experimental modes, data on the stability or instability of the boiler parameters over time (which is especially important for pulverized coal boilers), as well as to obtain current information on the state of regular control measurements in order to prepare for the next experiments. The results of observations are used as auxiliary material.

9. PROCESSING OF TEST RESULTS

9.1. Processing of test results is carried out according to the following formulas G email = (wr)email × F email; D i = iexit - iin ; h T = rq × rr × hk,where F- internal transverse section pipeline, m 2; t us - saturation temperature according to the pressure of the medium at the outlet of the circuit, °С; a- measuring tube flow rate; D R meas - differential pressure on the measuring tube, kgf/m 2 ; v- specific volume of the medium, m 3 /kg; F email- internal cross section of the element, m 2; i in,i out- medium enthalpy at the inlet and outlet of the circuit, kJ/kg (kcal/kg), taken from thermodynamic tables, i = f(t,P), pressure is taken at the inlet and outlet of the circuit; hk- the coefficient of constructive non-identity of the element (individual pipe), is taken according to the design data according to [1]. For explanations of the remaining letter designations, see paragraphs. 1.1.7 and 1.1.8.9.2. Errors in determining indicators based on measurement results are determined in the following way:d (wr) = d (G); D( tin) = D ( t); D( texit) = D ( t); D( temail) = D ( t); d(D R to) = d(D R).Absolute error D( t us) is found according to thermodynamic tables and is equal to half the unit of the last significant digit. The permissible absolute error in temperature measurement is determined by the formula where D TP- permissible error of thermocouples; D hp - communication line error caused by deviation of thermo-emf of extension wires; D etc- basic error of the device; D¶ i- additional error of the device from i-th influencing environmental factor; n pr- the number of factors affecting the device. The permissible relative error in measuring the flow rate, pressure drop and pressure is determined by the formulas: where dsu - permissible relative error of the narrowing device; d ¶ - allowable relative error of the sensor; detc - basic relative error of the device; d ¶ i , detci - additional relative errors of the sensor and the device from i-th external influencing factor; P ¶ - number of influencing factors on the sensor. 9.3. Before the start of processing, the time intervals of the experiments are specified and time marking is made on the chart tapes of the recorders (for stationary modes - with an interval of 5-10 minutes, for modes with disturbances - after 1 minute or after each clear). The timing of the tapes of all devices is checked. Readings are taken from the tapes using special scales, which are calibrated according to standard scales or according to individual calibrations of instruments and sensors. Unrepresentative measurement results are excluded from processing. 9.4. The results of measurements in stationary modes are averaged over time for the experiment: the parameters of the boiler according to the records in the observation logs, the rest of the indicators according to the tape recorders according to the markup. The processing of the results of measurements of temperatures and pressures of the medium along the steam-water path requires special attention, since the enthalpy is determined from them and the enthalpy increments in the heating surfaces are calculated, which is the basis of a large part of the processing. Consideration should be given to the possibility of significant errors in the determination of enthalpy during SKD in the zone of high heat capacities (at subcritical pressure - in the evaporative part). The pressure at the intermediate points of the path is determined by interpolation, taking into account direct measurements and the hydraulic calculation of the boiler. The average processing results are entered into tables and presented in the form of graphs (distribution of temperatures and enthalpies of the medium along the path, temperature and hydraulic calibrations, dependence of the indicators of thermal and hydraulic operation of the circuit on the load of the boiler and on regime factors, etc.). 9.5. The task of testing in transient conditions is to determine the deviations of flow rates and temperatures in the circuit elements from the initial stationary values ​​(in magnitude and rate of change). In view of this, the processing results are not averaged and are presented in the form of graphs depending on time. It is expedient to plot areas with stability violations on separate graphs with an enlarged time scale or to give photocopies of tapes. Kindling modes are also processed in the form of time graphs. 9.6. When processing hydraulic measurements, individual scales are used that correspond to the calibration of the sensor. The reading is made from the "zeros" marked on the tape during the experiments. For stationary modes, when measuring the flow rate, the readings of the pressure drop on the measuring device taken from the tape are recalculated into the values ​​of the flow rate or mass velocity. Recalculation is carried out according to the formulas given in clause 9.1, or according to auxiliary dependencies ( wr), G from D R meas, built on the basis of the specified formulas (for the operating range of temperatures and pressures of the medium). For transient modes, when plotting a time graph, it is allowed not to recalculate the flow measurement in the circuit elements and build the resulting graph in the values ​​of D R meas(showing approximate flow rates using the second scale on the graph). 9.7. The measured pressure values ​​are corrected for the height of the water column in the connecting line (from the sampling point to the sensor); on the measured pressure difference - correction for the difference in the height of the water column between the sampling points. 9.8. The most important part of the processing of test results is the comparison, analysis and interpretation of the obtained materials, assessment of their reliability and sufficiency. Preliminary analysis is carried out at intermediate stages of processing, which allows you to make the necessary adjustments in the course of work. In some more complex cases (for example, when results that differ from those expected are obtained, in order to assess the stability limits beyond the experimental data, etc.), it is advisable to perform additional calculations of hydraulic stability taking into account the experimental material.

10. PREPARATION OF THE TECHNICAL REPORT

10.1. Based on the test results, a technical report is drawn up, which is approved by the chief engineer of the enterprise or his deputy. The report should contain test materials, analysis of materials and conclusions on work with an assessment of the hydraulic stability of the boiler, conditions and limits of stability, as well as, if necessary, with recommendations for improving stability. The report must be drawn up in accordance with STP 7010000302-82 (or with GOST 7.32-81). 10.2. The report consists of the following sections: "Abstract", "Introduction", "Brief description of the boiler and the circuit under test", "Test methodology", "Test results and their analysis", "Conclusions and recommendations". The introduction formulates the goals and objectives of the tests, the fundamental approach to their implementation and the scope of work are determined. The description of the boiler should include design characteristics, equipment, necessary data from factory calculations. The section "Test Method" provides information on the experimental control scheme, measurement procedure and test procedure. In the section "Test results and their analysis" highlights the operating conditions of the boiler during the test period, provides detailed measurement results and their processing, as well as an assessment of the measurement error; the analysis of the results is given, the obtained indicators of hydraulic stability are considered, compared with the available calculations, the results are compared with the known results from other tests of similar equipment, the assessments of stability and the proposed recommendations are justified. The conclusions should contain an assessment of the hydraulic stability (for individual indicators and in general) depending on boiler load, other regime factors and from the influence of non-stationary processes. In case of detection of insufficient stability, recommendations are given to improve the reliability of operation (regime and reconstructive). 10.3. Graphic material includes: drawings (or sketches) of the boiler and its units, hydraulic diagram of the circuit under test, measurement scheme (with the necessary units), drawings of non-standard measuring devices, graphs of the results of the calculations, graphs of the measurement results (primary material and generalizing dependencies), sketches of proposals on reconstruction (if any). The graphic material should be sufficiently complete and convincing so that the reader (customer) can get a clear idea of ​​all the existing aspects of the tests carried out and the validity of the conclusions and recommendations made. 10.4. The report also includes a list of references and a list of illustrations. The appendix to the report includes summary tables of test data and calculations and copies of the necessary documents (acts, protocols).

11. SAFETY REQUIREMENTS

Persons participating in the testing must know and comply with the requirements set forth in [3], and have an entry in the knowledge test certificate.

Appendix 1

PRESSURE PIPE DESIGN

When choosing one or another design of measuring pressure tubes (Pitot tubes), one should be guided by the required pressure drop, the flow area of ​​the pipes, take into account the complexity of manufacturing one or another tube design, as well as the convenience of their installation. The designs of pressure tubes for measuring circulation and water rates are shown in Fig. . 3. The CKTI rod tube (see Fig. 3a) is usually installed at a depth of 1/3 D, which is essential for pipes of small diameter. In fig. 3b shows the design of the VTI cylindrical tube. For screen pipes with an inner diameter of 50-70 mm, the diameter of the measuring tube is assumed to be 8-10 mm, they are installed at a depth of 1/2 of the inner diameter of the pipe. The disadvantages of cylindrical tubes compared to rod tubes include their greater clutter of the internal section, and the advantages are their simpler manufacture and lower flow coefficient, which leads to an increase in the pressure drop of the sensor at the same water flow rate. Along with the above designs of pressure tubes for measuring velocities of water in the circuits, cylindrical through tubes are also used (see Fig. 3, c), which are distinguished by ease of manufacture - only turning and drilling of channels. The flow coefficient for these tubes is the same as for the cylindrical tubes of VTI. The specified measuring tube can be made of a simplified design - from two pieces of pipes of small diameter (see Fig. 3d). Parts of the tubes are welded in the middle with a partition between them, so that there is no communication between the left and right cavities of the tube. The pressure sampling holes are drilled near the baffle as close to each other as possible. After welding the tubes, the weld area must be thoroughly cleaned. To weld the tube into the screen or bypass pipe, it is welded to the fittings. For correct installation measuring tubes of any design along the water flow on the outer part of the end face of the cylinder or fittings, risks should be made. In fig. 4a shows the results of the calibration of rod tubes with the length of the measuring part equal to 1/2, 1/3, 1/6 D(D- pipe inner diameter). With a decrease in the length of the measuring part, the value of the tube flow coefficient increases. For pipe with h = 1/6D the flow coefficient approaches unity. With an increase in the inner diameter of the pipe, the flow coefficient decreases for all lengths of the active part of the meter. From fig. 4,a it can be seen that the smallest flow coefficient, and hence the largest pressure drop, have tubes with a length of the measuring part equal to 1/2 D. When using them, the influence of the inner diameter of the pipeline is significantly reduced. 4b the results of calibration of VTI tubes with a diameter of 10 mm are given with the installation of the measuring part at 1/2 D. Flow rate dependence a from the ratio of the diameter of the measuring tube to the inner diameter of the pipe in which it is installed, is given in fig. 4,c. The given flow coefficients are valid when measuring tubes are installed in screen tubes, for numbers Re, which are at the level of 10 3 , and acquire constant values for CKTI tubes at numbers Re³ (35 ¸40) ×10 3, and for VTI tubes at Re³ 20 × 10 3. In fig. 4, d shows the flow coefficient for a through cylindrical tube with a diameter of 20 mm, depending on the length of the stabilizing section L pipes with an inner diameter of 145 mm. In Fig. 4, e the dependence of the flow coefficient and the correction factor on the ratio of the diameters of the measuring tube and the pipe in which it is installed is shown. The actual flow coefficient in this case will be: a f= a × To where TO - factor that takes into account other factors. Correct installation of pressure tubes increases the accuracy of determining velocities. The holes in the tube that receive the pressure signal must be located strictly along the axis of the pipe in which it is installed. 4f. Comparison of pressure tubes designed by TsKTI and VTI with the active length of the measuring part equal to 1/2 D shows that the pressure drop created at the same flow rate for VTI tubes for screen tubes with an inner diameter of 50 and 76 mm, respectively, is 1.3 and 1.2 times greater than for TsNTI tubes. This ensures greater measurement accuracy, especially at low water velocities. Therefore, when the clutter of the inner section of the pipe with a measuring tube is not of decisive importance (for pipelines of relatively large diameter), then VTI tubes should be used to measure water velocities. CKTI tubes are more often used on coils of small internal diameter (up to 20 mm). Measurement of water velocities less than 0.3 m/s, even with VTI tubes, is not recommended, since in this case the pressure drop is less than 70-90 Pa (7 -9 kgf/m 2), which is less than the lower guaranteed measurement limit for sensors used in flow measurement.

Annex 2

PREPARATORY WORKS FOR TESTING THE SCREENS OF THE TGMP-314 BOILER OF THE KOSTROMSKAYA GRES

Name

Quantity, pcs.

Production of temperature inserts

Insertion of temperature inserts in LF and MF

Opening insulation on collectors and pipelines (NRCH, SRCH, VRC)

25 plots

Installation and welding of surface thermocouples

Switching of thermocouples and inserts to junction boxes (SK)

Installation SK-24

Laying compensation cable KMTB -14

Installation of pressure pipes (with drilling in supply pipes and LFC coils)

Pressure sampling unit

Installation for selection of signals on the kindling flow of feed water (from the standard diaphragm)

Laying of connecting (impulse) pipes

Installation of flow sensors

Manufacturing and installation of a shield for 20 devices

Installation of secondary devices (KSP, KSU, KSD)

Work space preparation

Technical inspection(revision) of standard measurement systems for the steam-water path

Shield lighting installation.

Signature: _________________________________________________ (test leader from Soyuztechenergo) DEVICES AND MATERIALS SUPPLIED BY THE CUSTOMER FOR TESTING BOILER SCREENS Signature: _________________________________________________ (test leader from Soyuztekhenergo)

Name

Quantity, pcs.

Differential pressure sensor DM, 0.4 kgf/cm2 (for 400 kg/cm2)

Pressure sensor MED 0-400 kgf/cm 2

Differential pressure sensor DME, 0-250 kgf/cm2 (at 400 kgf/cm2)

Single-point KSD device

KSU single-point device

Device KSP-4, 0-600°, XA, 12-point

Compensation wire MK

Thermoelectrode wire XA

Glassstocking

Silica tape (glass)

Insulating tape

Charting strip for KSP, 0-600°, XA

Chart tape for KSU (KSD), 0-100%,

Batteries are flat

Batteries are round

Signature: _________________________________________________ (test manager from Soyuztechenergo)

Annex 3

I approve:
Chief Engineer of GRES

WORKING PROGRAM FOR CARRYING OUT EXPERIMENTS OF TESTING THE HYDRAULIC STABILITY OF NRCH AND SRCH-1 OF BOILER No. 1 (WITH LDPE)

1. Experience 1. Set the following mode: power unit load - 290-300 MW, fuel - dust (without fuel oil illumination), excess air - 1.2 (3-3.5% oxygen), feed water temperature - 260 ° C , the 2nd and 3rd injections are in operation (30-40 t/h per flow). The rest of the parameters are maintained in accordance with the regime map and the current instructions. During the experiment, if possible, do not make any changes in the mode. All operating automation is in operation. The duration of the experiment is 2 hours. Experiment 1 a. The effect of the "Water-fuel" imbalance on the stability of the hydrodynamics is checked. Set the same mode as in experiment 1. Turn off the fuel regulator. Sharply reduce the feed water flow rate along the "A" stream by 80 t/h without changing the fuel consumption. After 10 minutes, in agreement with the Soyuztekhenergo representative, restore the initial water flow. During the experiment, temperature control along the boiler path should be carried out by injections. Permissible limits of short-term deviation of the temperature of live steam - 525-560 ° C (no more than 3 minutes), temperatures of the medium along the boiler path ± 50 ° C from the calculated ones (no more than 5 minutes, see clause 4 of this appendix). Duration of the experiment - 1 Part 2. Experience 2. Set the following mode: power unit load - 250-260 MW, fuel - dust (without fuel oil illumination), excess air - 1.2-1.25 (3.5-4% oxygen), temperature feed water - 240-245°C, the 2nd and 3rd injections are in operation (25-30 t/h per flow). The rest of the parameters are maintained in accordance with the regime map and the current instructions. During the experiment, if possible, do not make any changes in the mode. All operating automation is in operation. The duration of the experiment is 2 hours. Experiment 2a. The effect of skew on the burners is checked. Set the same mode as in experiment 2, but on 13 dust feeders (dust feeders No. 9,10,11 are turned off). The duration of the experiment is 1.5 hours. Experiment 2b. The effect of the imbalance "Water-fuel" is checked. Set the same mode as in experiment 2a. Turn off the fuel regulator. Dramatically reduce the feed water flow rate on stream "A" by 70 t/h without changing the fuel flow rate. After 10 minutes, in agreement with the Soyuztechenergo representative, restore the initial water flow. During the experiment, temperature control along the boiler path should be carried out by injection. Permissible limits of short-term deviation of the temperature of fresh steam 525-560°C (no more than 3 min), ambient temperatures along the boiler path ± 50°C from the calculated one (no more than 5 min, see clause 4 of this appendix). The duration of the experiment is 1 hour .3. Experiment 3. Set the following mode: power unit load 225-230 MW, fuel - dust (at least 13 dust feeders are in operation, without fuel oil illumination), excess air - 1.25 (4-4.5% oxygen), feed water temperature - 235-240°С, 2nd and 3rd injections are in operation (20-25 t/h per stream). The remaining parameters are maintained in accordance with the regime map and the current instructions. During the experiment, if possible, do not make any changes in the mode. All operating automation is in operation. The duration of the experiment is 2 hours. Experiment 3a. The influence of the imbalance "Water-fuel" and the inclusion of burners is checked. Set the same mode as in experiment 3. Increase the excess air to 1.4 (6-6.5% oxygen). Turn off the fuel regulator. Dramatically increase fuel consumption by increasing the speed of the dust feeders by 200-250 rpm without changing the water flow rate. After 10 minutes, in agreement with the representative of Soyuztechenergo, restore the original speed. Stabilize the regime. Dramatically increase fuel consumption by simultaneously turning on two dust feeders in the left semi-furnace without changing the water flow rate by flow. After 10 minutes, in agreement with the representative of Soyuztekhenergo, restore the initial fuel consumption. During the experiment, temperature control along the boiler path is carried out by injections. Permissible limits of short-term deviation of the overheating temperature - 525-560°C (no more than 3 minutes), ambient temperatures along the boiler path ± 50°C from the calculated ones (no more than 5 minutes, see clause 4 of this appendix). Duration of the experiment - 2 hours Notes: 1. The CTC assigns a responsible representative for each experience. 2. All operational actions during the experiment are carried out by the shift personnel at the direction (or with the knowledge and agreement) of the responsible representative of Soyuztechenergo. 3. In case of occurrence emergencies the experiment is terminated, and the watch personnel act in accordance with the relevant instructions. 4. Limiting short-term temperatures of the medium along the boiler path, ° С: behind SRF-P 470 to VZ 500 behind screens - I 530 behind screens - II 570. Signature: _________________________________________________ (test manager from Soyuztekhenergo) Agreed: _____________________________________________ (heads of GRES workshops)

List of used literature

1. Hydraulic calculation of boiler units (normative method). M.: "Energy", 1978, - 255 p. 2. Kemelman D.N., Eskin N.B., Davidov A.A. Adjustment of boiler units (reference book). M.: "Energy", 1976. 342 p. 3. Safety regulations for the operation of thermal mechanical equipment of power plants and heating networks. Moscow: Energoatomizdat, 1985, 232 p.