Protection of residential buildings equipped with a roof boiler room from noise and vibrations. Measures to reduce noise levels Permissible noise level in the boiler room

Ph.D. L.V. Rodionov, head of support department scientific research; Ph.D. S.A. Gafurov, senior researcher; Ph.D. V.S. Melentyev, senior researcher; Ph.D. A.S. Gvozdev, Federal State Autonomous Educational Institution of Higher Education “Samara National research university named after academician S.P. Koroleva", Samara

To ensure hot water and heating modern apartment buildings(MKD) projects sometimes include roof boiler houses. This solution is cost-effective in some cases. At the same time, often when installing boilers on foundations, proper vibration insulation is not provided. As a result, residents of the upper floors are subject to constant noise exposure.

According to the sanitary standards in force in Russia, the sound pressure level in residential premises should not exceed 40 dBA during the day and 30 dBA at night (dBA is an acoustic decibel, a unit of measurement of noise level taking into account human perception of sound. - Ed.).

Specialists from the Institute of Machine Acoustics at Samara State Aerospace University (IAM at SSAU) measured the sound pressure level in the living space of an apartment located under the roof boiler room of a residential building. It turned out that the source of the noise was the roof boiler room equipment. Despite the fact that this apartment is separated from the roof boiler room by a technical floor, according to the measurement results, an excess of daily sanitary standards was recorded, both at the equivalent level and at an octave frequency of 63 Hz (Fig. 1).

The measurements were performed during the daytime. At night, the operating mode of the boiler room remains virtually unchanged, and the background noise level may be lower. Since it turned out that the “problem” was already present during the day, it was decided not to carry out measurements at night.

Figure 1 . Sound pressure level in the apartment in comparison with sanitary standards.

Localizing the source of noise and vibration

For more precise definition At the “problem” frequency, sound pressure levels were measured in the apartment, boiler room and on the technical floor in different operating modes of the equipment.

The most typical mode of equipment operation, in which a tonal frequency appears in the low-frequency region, is the simultaneous operation of three boilers (Fig. 2). It is known that the frequency of boiler operating processes (combustion inside) is quite low and falls in the range of 30-70 Hz.

Figure 2. Sound pressure level in various rooms when three boilers are operating simultaneously

From Fig. 2 shows that the frequency of 50 Hz prevails in all measured spectra. Thus, the main contribution to the spectra of sound pressure levels in the rooms under study is made by boilers.

The level of background noise in the apartment does not change much when the boiler equipment is turned on (except for the frequency of 50 Hz), so we can conclude that the sound insulation of the two floors separating the boiler room from the living rooms is sufficient to reduce the level of airborne noise produced by the boiler equipment to sanitary standards. Therefore, one should look for other (not direct) ways of spreading noise (vibration). Likely, high level sound pressure at 50 Hz is due to structural noise.

To localize the source of structural noise in residential premises, as well as to identify vibration propagation paths, vibration acceleration measurements were additionally carried out in the boiler room, on the technical floor, as well as in the living space of the apartment on the top floor.

The measurements were carried out at various operating modes of boiler equipment. In Fig. Figure 3 shows the vibration acceleration spectra for the mode in which all three boilers operate.

Based on the results of the measurements, the following conclusions were made:

– in the apartment on the top floor under the boiler room, sanitary standards are not met;

– the main source of increased noise in residential premises is the combustion process in boilers. The prevailing harmonic in the noise and vibration spectra is the frequency of 50 Hz.

– lack of proper vibration isolation of the boiler from the foundation leads to the transfer of structural noise to the floor and walls of the boiler room. Vibration spreads both through the boiler supports and through the pipes with transmission from them to the walls, as well as the floor, i.e. in places where they are rigidly connected.

– measures should be developed to combat noise and vibration along the path of their propagation from the boiler.

A) b)
V)

Figure 3 . Vibration acceleration spectra: a – on the support and foundation of the boiler, on the floor of the boiler room; b – on the support of the boiler exhaust pipe and on the floor near the boiler exhaust pipe; c – on the wall of the boiler room, on the wall of the technical floor and in the living area of ​​the apartment.

Development of a vibration protection system

Based on a preliminary analysis of the mass distribution of the gas boiler structure and equipment, cable vibration isolators VMT-120 and VMT-60 with a rated load on one vibration isolator (VI) of 120 and 60 kg, respectively, were selected for the project. The vibration isolator diagram is shown in Fig. 4.

Figure 4. 3D model of cable vibration isolator model range TDC.

Figure 5. Vibration isolator fastening schemes: a) support; b) suspended; c) lateral.

Three variants of the vibration isolator fastening scheme have been developed: support, suspended and lateral (Fig. 5).

Calculations showed that side diagram The installation can be implemented using 33 vibration isolators VMT-120 (for each boiler), which is not economically feasible. In addition, very serious welding work is expected.

When implementing a suspended scheme, the entire structure becomes more complicated, since wide and sufficiently long corners must be welded to the boiler frame, which will also be welded from several profiles (to provide the necessary mounting surface).

In addition, the technology for installing the boiler frame on these skids with VIs is complex (it is inconvenient to attach the VIs, it is inconvenient to position and center the boiler, etc.). Another disadvantage of this scheme is the free movement of the boiler in lateral directions (swinging in the transverse plane on the VI). The number of vibration isolators VMT-120 for this scheme is 14.

The frequency of the vibration protection system (VPS) is about 8.2 Hz.

The third, most promising and technologically simpler option is with a standard support circuit. It will require 18 vibration isolators VMT-120.

The calculated frequency of the VZS is 4.3 Hz. In addition, the design of the VIs themselves (part of the cable rings are located at an angle) and their proper placement around the perimeter (Fig. 6) allows such a design to accommodate a lateral load, the value of which will be about 60 kgf for each VI, while the vertical load on each VI is about 160 kgf.

Figure 6. Placement of vibration isolators on the frame with a support diagram.

Design of a vibration protection system

Based on data from static tests and dynamic calculations of VI parameters, a vibration protection system for a boiler room in a residential building was developed (Fig. 7).

The vibration protection facility includes three boilers of the same design 1 installed on concrete foundations with metal ties; piping system 2 for the supply of cold water and the removal of heated water, as well as the removal of combustion products; pipe system 3 for supplying gas to the boiler burners.

The created vibration protection system includes external vibration protection supports for boilers 4 designed to support pipelines 2 ; internal vibration protection belt of boilers 5 , designed to isolate vibration of boilers from the floor; external vibration mounts 6 For gas pipes 3.

Figure 7. General view boiler room with installed vibration protection system.

Main design parameters of the vibration protection system:

1. The height from the floor to which it is necessary to raise the load-bearing frames of the boilers is 2 cm (installation tolerance minus 5 mm).

2. Number of vibration isolators per boiler: 19 VMT-120 (18 - in the internal belt bearing the weight of the boiler, and 1 - on the external support to dampen vibrations of the water pipeline), as well as 2 vibration isolators VMT-60 on external supports - for vibration protection of the gas pipeline.

3. The “support” type loading scheme works in compression, providing good vibration isolation. The natural frequency of the system is in the range of 5.1-7.9 Hz, which provides effective vibration protection in the region above 10 Hz.

4. The damping coefficient of the vibration protection system is 0.4-0.5, which provides a gain at resonance of no more than 2.6 (oscillation amplitude no more than 1 mm with an input signal amplitude of 0.4 mm).

5. To adjust the horizontality of boilers, nine seats for vibration isolators of a similar type are provided on the sides of the boiler in the U-shaped profiles. Only five are nominally installed.

During installation, it is possible to place vibration isolators in any order in any of the nine places provided to achieve alignment of the center of mass of the boiler and the center of rigidity of the vibration protection system.

6. Advantages of the developed vibration protection system: simplicity of design and installation, insignificant rise of boilers above the floor, good damping characteristics of the system, possibility of adjustment.

The effect of using the developed vibration protection system

With the introduction of the developed vibration protection system, the sound pressure level in the residential premises of the upper floor apartments decreased to an acceptable level (Fig. 8). The measurements were also carried out at night.

From the graph in Fig. 8 it can be seen that in the standardized frequency range and at the equivalent sound level, sanitary standards in residential premises are met.

The effectiveness of the developed vibration protection system when measured in a residential area at a frequency of 50 Hz is 26.5 dB, and at an equivalent sound level of 15 dBA (Fig. 9).

Figure 8 . Sound pressure level in the apartment in comparison with sanitary standards, taking into account developed vibration protection system.

Figure 9. Sound pressure level in one-third octave frequency bands in a living room when three boilers are operating simultaneously.

Conclusion

The created vibration protection system makes it possible to protect a residential building equipped with a roof boiler room from vibrations created by the operation of gas boilers, as well as to ensure normal vibration operating conditions for the most gas equipment together with the pipeline system, increasing the service life and reducing the likelihood of accidents.

The main advantages of the developed vibration protection system are simplicity of design and installation, low cost in comparison with other types of vibration isolators, resistance to temperatures and pollution, insignificant rise of boilers above the floor, good damping characteristics of the system, and the possibility of adjustment.

The vibration protection system prevents the propagation of structural noise from the roof boiler room equipment throughout the building structure, thereby reducing the sound pressure level in residential premises to an acceptable level.

Literature

1. Igolkin, A.A. Reducing noise in residential premises through the use of vibration isolators [Text] / A.A. Igolkin, L.V. Rodionov, E.V. Shakhmatov // Security in the technosphere. No. 4. 2008. pp. 40-43.

2. SN 2.2.4/2.1.8.562-96 “Noise in workplaces, in residential and public buildings and in residential areas,” 1996, 8 p.

3. GOST 23337-78 “Noise. Methods for measuring noise in residential areas and in residential and public buildings”, 1978, 18 p.

4. Shakhmatov, E.V. A comprehensive solution to the problems of vibroacoustics of mechanical engineering and aerospace engineering products [Text] / E.V. Shakhmatov // LAP LAMBERT Academic Publishing GmbH&CO.KG. 2012. 81 p.

From the editor. On October 27, 2017, Rospotrebnadzor published information on its official website “On the impact of physical factors, including noise, on public health”, which notes that in the structure of citizens’ complaints about various physical factors, the largest specific gravity(over 60%) are complaints about noise. The main ones are complaints from residents, including about acoustic discomfort from ventilation systems and refrigeration equipment, noise and vibration during operation of heating equipment.

Reasons increased level noise created by these sources is due to the insufficiency of noise protection measures at the design stage, installation of equipment with deviations from design solutions without assessing the generated levels of noise and vibration, unsatisfactory implementation of noise protection measures at the commissioning stage, placement of equipment not provided for in the project, as well as unsatisfactory control over the operation of the equipment.

The Federal Service for Supervision of Consumer Rights Protection and Human Welfare draws the attention of citizens that in the event of adverse effects of physical factors, incl. noise, you should contact the territorial Office of Rospotrebnadzor for the constituent entity of the Russian Federation.

The number of requests from citizens received by the Office of Rospotrebnadzor in the Tyumen Region about the deterioration of living conditions due to exposure to excess noise levels increases every year.

In 2013, 362 complaints were received (in total regarding violations of peace and quiet, accommodation and noise), in 2014 - 416 complaints, and in 2015, 80 complaints were already received.

According to established practice, after residents apply, the Department orders measurements of noise and vibration levels in residential premises. If necessary, measurements are carried out in organizations located near apartments, where, for example, “noisy” equipment is operated - a source of noise (restaurant, cafe, store, etc.). If noise and vibration levels exceed permissible values, according to SN 2.2.4/2.1.8.562-96 “Noise in workplaces, in residential and public buildings and in residential areas”, addressed to the owners of noise sources - legal entities, individual entrepreneurs - the Department issues an order to eliminate identified violations of sanitary legislation.

How can you reduce the noise from the equipment listed above so that during its operation there are no complaints from the residents of the house? Certainly, ideal option-provide necessary measures at the design stage of a residential building, then the development of noise-reducing measures is always possible, and their implementation during construction is tens of times cheaper than in those houses that have already been built.

The situation is completely different if the building has already been built and there are noise sources in it that exceed current standards. Then, most often, noisy units are replaced with less noisy ones and measures are taken to vibration insulate the units and the communications leading to them. Next, we will look at specific sources of noise and measures for vibration isolation of equipment.

NOISE FROM THE AIR CONDITIONER

The use of three-link vibration isolation, when the air conditioner is installed on the frame through a vibration isolator, and the frame - on a reinforced concrete slab through rubber gaskets (in this case, the reinforced concrete slab is installed on spring vibration isolators on the roof of the building), leads to a reduction in penetrating structural noise to levels acceptable in residential premises.

To reduce noise, it is necessary, in addition to strengthening the noise and vibration insulation of the air duct walls and installing a muffler on the air duct of the ventilation unit (from the premises), to attach the expansion chamber and air ducts to the ceiling through vibration-isolating hangers or gaskets.

NOISE FROM THE BOILER ROOM ON THE ROOF

To protect against noise from a boiler room located on the roof of a house, foundation slab The roof boiler room is installed on spring vibration isolators or a vibration-isolating mat made of a special material. Pumps and boiler units equipped in the boiler room are installed on vibration isolators and soft inserts are used.

Pumps in the boiler room must not be installed with the engine facing down! They must be installed in such a way that the load from the pipelines is not transferred to the pump housing. In addition, the noise level is higher with a higher power pump or if several pumps are installed. To reduce noise, the boiler room foundation slab can also be placed on spring shock absorbers or high-strength multilayer rubber and rubber-metal vibration isolators.

Current regulations do not allow the placement of a roof boiler room directly on the ceiling of residential premises (the ceiling of a residential premises cannot serve as the basis for the floor of the boiler room), as well as adjacent to residential premises. It is not allowed to design rooftop boiler houses on buildings of preschool and school institutions, medical buildings of clinics and hospitals with 24-hour stay of patients, on dormitory buildings of sanatoriums and recreational facilities. When installing equipment on the roof and ceilings, it is advisable to place it in places farthest from the protected objects.

NOISE FROM INTERNET EQUIPMENT

According to the recommendations for the design of communication systems, informatization and dispatching of housing construction projects, it is recommended to install cellular antenna amplifiers in a metal cabinet with a locking device on technical floors, attics or stairwells of the upper floors. If it is necessary to install house amplifiers on different floors of multi-story buildings, they should be installed in metal cabinets in close proximity to the riser under the ceiling, usually at a height of at least 2 m from the bottom of the cabinet to the floor.

When installing amplifiers on technical floors and attics, to eliminate the transmission of vibration from a metal cabinet with a locking device, the latter must be installed on vibration isolators.

EXIT - VIBRATION ISOLATORS AND “FLOATING” FLOORS

For ventilation and refrigeration equipment on the upper, lower and intermediate technical floors of residential buildings, hotels, multifunctional complexes or in the vicinity of noise-regulated rooms where people are constantly present, the units can be installed on factory-made vibration isolators on a reinforced concrete slab. This slab is mounted on a vibration-isolating layer or springs on a “floating” floor (an additional reinforced concrete slab on a vibration-isolating layer) in a technical room. It should be noted that fans and external condenser units, which are currently produced, are equipped with vibration isolators only at the request of the customer.

“Floating” floors without special vibration isolators can only be used with equipment having operating frequencies of more than 45-50 Hz. These are, as a rule, small machines, the vibration isolation of which can be ensured in other ways. The effectiveness of floors on an elastic base at such low frequencies is low, so they are used exclusively in combination with other types of vibration isolators, which provides high vibration isolation at low frequencies (due to vibration isolators), as well as at medium and high frequencies (due to vibration isolators and a “floating” floor ).

The floating floor screed must be carefully isolated from the walls and the load-bearing floor slab, since the formation of even small rigid bridges between them can significantly worsen its vibration-isolating properties. Where the “floating” floor adjoins the walls, there must be a seam made of non-hardening materials that does not allow water to pass through.

NOISE FROM THE GARBAGE CHIP

To reduce noise, it is necessary to comply with the requirements of the standards and not design the waste chute adjacent to residential premises. The garbage chute should not be adjacent to or located in walls enclosing residential or office premises with regulated noise levels.

The most common measures to reduce noise from garbage chutes are:

• “floating” floors are provided in waste collection rooms;
• with the consent of the residents of all apartments at the entrance, the garbage chute is sealed (or eliminated) with the placement of a garbage chamber for wheelchairs, a room for the concierge, etc. in the premises. ( positive point in that, in addition to noise, odors disappear, the possibility of rats and insects, the likelihood of fires, dirt, etc. is eliminated);
• the loading valve bucket is mounted framed with rubber or magnetic seals;
• decorative heat and noise insulating lining of the garbage chute trunk made of building materials separated from the building structures by soundproofing gaskets.

Today, many construction companies offer their services, various designs to increase the sound insulation of walls and promise complete silence. It should be noted that in fact, no structures can remove the structural noise transmitted through the floors, ceilings and walls when disposing of solid household waste into a garbage chute.

NOISE FROM ELEVATORS

In SP 51.13330.2011 “Noise protection. The updated version of SNiP 03/23/2003 states that it is advisable to locate elevator shafts in the stairwell between flights of stairs (clause 11.8). When making an architectural and planning decision for a residential building, it should be provided that the built-in elevator shaft is adjacent to rooms that do not require increased protection from noise and vibration (halls, corridors, kitchens, sanitary facilities). All elevator shafts regardless of planning solution must be self-supporting and have an independent foundation.

The shafts must be separated from other building structures with an acoustic seam of 40-50 mm or vibration-isolating pads. Acoustic mineral wool slabs on a basalt or fiberglass base and various foamed polymer roll materials are recommended as the material for the elastic layer.

To protect the elevator installation from structural noise, its drive motor with gearbox and winch, usually installed on one common frame, are vibration-isolated from the supporting surface. Modern elevator drive units are equipped with appropriate vibration isolators installed under metal frames on which motors, gearboxes and winches are rigidly mounted, and therefore additional vibration insulation of the drive unit is usually not required. In this case, it is additionally recommended to make a two-stage (two-link) vibration isolation system by installing a support frame through vibration isolators on a reinforced concrete slab, which is also separated from the floor by vibration isolators.

The operation of elevator winches installed on two-stage vibration isolation systems has shown that noise levels from them do not exceed standard values ​​in the nearest residential premises (through 1-2 walls). For practical purposes, care must be taken to ensure that vibration isolation is not compromised by occasional rigid bridges between the metal frame and the supporting surface. Electrical supply cables must have sufficiently long flexible loops. However, the operation of other elements of elevator installations (control panels, transformers, cabin and counterweight shoes, etc.) may be accompanied by noise above standard values.

It is prohibited to design the elevator engine room floor as a continuation of the ceiling slab of the upper floor living room.

NOISE FROM TRANSFORMERSSUBSTATIONSON THE GROUND FLOORS

To protect residential and other premises with regulated noise levels from noise from transformer substations, the following conditions must be observed:

• premises of built-in transformer substations;
• should not be adjacent to noise-protected premises;
• built-in transformer substations should be
• located in basements or on the first floors of buildings;
• transformers must be installed on vibration isolators designed accordingly;
• electrical panels containing electromagnetic communication devices, and separately installed oil switches With electric drive must be mounted on rubber vibration isolators (air disconnectors do not require vibration insulation);
• ventilation devices in the premises of built-in transformer substations must be equipped with noise suppressors.

To further reduce noise from the built-in transformer substation, it is advisable to treat its ceilings and interior walls sound-absorbing cladding.

Built-in transformer substations must be protected from electromagnetic radiation (a mesh made of a special material with grounding to reduce the level of radiation from the electrical component and a steel sheet for the magnetic component).

NOISE FROM ATTACHED BOILER ROOMS,BASEMENT PUMPS AND PIPES

Boiler room equipment (pumps and pipelines, ventilation units, air ducts, gas boilers, etc.) must be vibration-insulated using vibration foundations and soft inserts. Ventilation units are equipped with silencers.

To vibration-proof pumps located in basements, elevator units in individual heating units (IHP), ventilation units, refrigeration chambers, and the above equipment are installed on vibration foundations. Pipelines and air ducts are vibration-insulated from the house structures, since the predominant noise in apartments located above may not be the basic noise from the equipment in the basement, but that which is transmitted to the enclosing structures through the vibration of pipelines and equipment foundations. It is prohibited to install built-in boiler rooms in residential buildings.

In piping systems connected to the pump, it is necessary to use flexible inserts - rubber-fabric hoses or rubber-fabric hoses reinforced with metal spirals, depending on the hydraulic pressure in a network, 700-900 mm long. If there are pipe sections between the pump and the flexible insert, the sections should be attached to the walls and ceilings of the room on vibration-isolating supports, suspensions or through shock-absorbing pads. Flexible inserts should be located as close as possible to the pumping unit, both on the discharge and suction lines.

To reduce noise and vibration levels in residential buildings from the operation of heat and water supply systems, it is necessary to isolate the distribution pipelines of all systems from the building structures at the places where they pass through the load-bearing structures (entering into residential buildings and conclusions from them). The gap between the pipeline and the foundation at the inlet and outlet must be at least 30 mm.

Prepared based on materials from the journal Sanitary and Epidemiological Interlocutor (No. 1(149), 2015

V.B. Tupov
Moscow Energy Institute (Technical University)

ANNOTATION

The original developments of MPEI to reduce noise from power equipment of thermal power plants and boiler houses are considered. Examples are given of noise reduction from the most intense noise sources, namely from steam emissions, combined-cycle plants, draft machines, hot-water boilers, transformers and cooling towers, taking into account the requirements and specifics of their operation at energy facilities. The test results of mufflers are given. The presented data allows us to recommend MPEI silencers for widespread use at energy facilities in the country.

1. INTRODUCTION

Solutions to environmental issues during the operation of power equipment are a priority. Noise is one of the important factors polluting the environment, reducing negative impact which is subject to environmental protection laws atmospheric air" and "On the protection of the natural environment", and sanitary standards SN 2.2.4/2.1.8.562-96 establish permissible noise levels in workplaces and residential areas.

The normal operation of power equipment is associated with noise emissions that exceed sanitary standards not only on the territory of power facilities, but also in the surrounding area. This is especially important for energy facilities located in major cities close to residential areas. The use of combined cycle gas units (CCP) and gas turbine units (GTU), as well as equipment of higher technical parameters associated with increased sound pressure levels in the surrounding area.

Some energy equipment has tonal components in its emission spectrum. The round-the-clock operation cycle of power equipment causes a particular danger of noise exposure for the population at night.

In accordance with sanitary standards, sanitary protection zones (SPZ) of thermal power plants of equivalent electrical power 600 MW and above, using coal and fuel oil as fuel, must have a sanitary protection zone of at least 1000 m, operating on gas and gas-oil fuel - at least 500 m. For thermal power plants and district boiler houses with a thermal capacity of 200 Gcal and above, operating on coal and fuel oil for fuel, the sanitary protection zone is at least 500 m, and for those operating on gas and reserve fuel oil - at least 300 m.

Sanitary norms and rules are established minimum dimensions sanitary zone, and actual dimensions may be larger. Exceeding permissible standards from constantly operating equipment of thermal power plants (TPPs) can reach 25-32 dB for work areas; for residential areas - 20-25 dB at a distance of 500 m from a powerful thermal power plant (TPP) and 15-20 dB at a distance of 100 m from a large district thermal station (RTS) or quarterly thermal station (CTS). Therefore, the problem of reducing noise impact from energy facilities is relevant, and in the near future its importance will increase.

2. EXPERIENCE IN NOISE REDUCTION FROM POWER EQUIPMENT

2.1. Main areas of work

Excess of sanitary standards in the surrounding area is formed, as a rule, by a group of sources, the development of measures to reduce noise, which receive much attention both abroad and in our country. The works on noise suppression of power equipment of such companies as Industrial acoustic company (IAC), BB-Acustic, Gerb and others are known abroad, and in our country - the developments of YuzhVTI, NPO TsKTI, ORGRES, VZPI (Open University), NIISF, VNIAM etc. .

Since 1982, the Moscow Energy Institute (Technical University) has also been carrying out a set of works to solve this problem. Here for recent years New effective silencers for the most intense noise sources from:

steam emissions;

combined cycle gas plants;

draft machines (smoke exhausters and blower fans);

hot water boilers;

transformers;

cooling towers and other sources.

Below are examples of noise reduction from power equipment using MPEI developments. The work on their implementation has a high social significance, which consists in reducing the noise impact to sanitary standards for large number population and personnel of energy facilities.

2.2. Examples of noise reduction from power equipment

Discharges of steam from power boilers into the atmosphere are the most intense, albeit short-term, source of noise both for the territory of the enterprise and for the surrounding area.

Acoustic measurements show that at a distance of 1 - 15 m from the steam exhaust of a power boiler, sound levels exceed not only the permissible, but also the maximum permissible sound level (110 dBA) by 6 - 28 dBA.

Therefore, the development of new effective steam silencers is an urgent task. A noise suppressor for steam emissions (MEI silencer) was developed.

The steam silencer has various modifications depending on the required reduction in exhaust noise level and the characteristics of the steam.

Currently, MPEI steam silencers have been implemented at a number of energy facilities: Saransk Thermal Power Plant No. 2 (CHP-2) of OJSC “Territorial Generating Company-6”, boiler OKG-180 of OJSC “Novolipetsk Iron and Steel Works”, CHPP-9, TPP-11 of OJSC “Novolipetsk Iron and Steel Works” Mosenergo". Steam consumption through the silencers ranged from 154 t/h at Saransk CHPP-2 to 16 t/h at CHPP-7 of Mosenergo OJSC.

MPEI mufflers were installed on the exhaust pipelines after the GPC of boilers st. No. 1, 2 CHPP-7 branch of CHPP-12 of Mosenergo OJSC. The efficiency of this noise suppressor, obtained from the measurement results, was 1.3 - 32.8 dB across the entire spectrum of standardized octave bands with geometric mean frequencies from 31.5 to 8000 Hz.

On boilers st. No. 4, 5 CHPP-9 of Mosenergo OJSC, several MPEI silencers were installed on the steam discharge after the main safety valves(GPC). The tests carried out here showed that the acoustic efficiency was 16.6 - 40.6 dB across the entire spectrum of standardized octave bands with geometric mean frequencies 31.5 - 8000 Hz, and in terms of sound level - 38.3 dBA.

MPEI mufflers, in comparison with foreign and other domestic analogues, have high specific characteristics, allowing to achieve maximum acoustic effect with minimal muffler weight and maximum steam flow through the muffler.

MEI steam silencers can be used to reduce the noise of superheated and wet steam being discharged into the atmosphere, natural gas etc. The design of the muffler can be used in a wide range of discharge steam parameters and can be used both on units with subcritical parameters and on units with supercritical parameters. The experience of using MPEI steam silencers has shown the necessary acoustic efficiency and reliability of the silencers at various facilities.

When developing noise suppression measures for gas turbine plants, the main attention was paid to the development of silencers for gas paths.

Based on the recommendations of the Moscow Power Engineering Institute, the designs of noise suppressors for gas paths of waste heat boilers of the following brands were made: KUV-69.8-150 manufactured by Dorogobuzhkotlomash OJSC for the Severny Settlement gas turbine power plant, P-132 manufactured by Podolsk Machine-Building Plant JSC (PMZ JSC) for Kirishskaya GRES, P-111 produced by PMZ JSC for CHPP-9 of Mosenergo JSC, waste heat boiler under license from Nooter/Eriksen for power unit PGU-220 of Ufimskaya CHPP-5, KGT-45/4.0- 430-13/0.53-240 for the Novy Urengoy Gas Chemical Complex (GCC).

A set of works to reduce the noise of gas paths was carried out for the Severny Settlement GTU-CHP.

The Severny Settlement GTU-CHP contains a two-case HRSG designed by Dorogobuzhkotlomash OJSC, which is installed after two FT-8.3 gas turbines from Pratt & Whitney Power Systems. Evacuation flue gases from the HRSG is carried out through one chimney.

Conducted acoustic calculations showed that in order to meet sanitary standards in a residential area at a distance of 300 m from the mouth of the chimney, it is necessary to reduce noise in the range from 7.8 dB to 27.3 dB at geometric mean frequencies of 63-8000 Hz.

A dissipative plate noise muffler developed by MPEI to reduce the exhaust noise of a gas turbine unit with a gas turbine unit is located in two metal noise-attenuation boxes of the unit with dimensions of 6000x6054x5638 mm above the convective packages in front of the confusers.

At the Kirishi State District Power Plant, a steam-gas unit PGU-800 with a P-132 horizontal unit and a gas turbine unit SGT5-400F (Siemens) is currently being implemented.

Calculations have shown that the required reduction in noise level from the gas turbine exhaust tract is 12.6 dBA to ensure a sound level of 95 dBA at 1 m from the mouth of the chimney.

To reduce noise in the gas ducts of the KU P-132 at the Kirishi State District Power Plant, a cylindrical muffler has been developed, which is located in the chimney internal diameter 8000 mm.

The noise suppressor consists of four cylindrical elements placed evenly in the chimney, while the relative flow area of ​​the silencer is 60%.

The calculated efficiency of the muffler is 4.0-25.5 dB in the range of octave bands with geometric mean frequencies of 31.5 - 4000 Hz, which corresponds to an acoustic efficiency at a sound level of 20 dBA.

The use of silencers to reduce noise from smoke exhausters using the example of CHPP-26 of Mosenergo OJSC in horizontal sections is given in.

In 2009, to reduce gas path noise, centrifugal smoke exhausters D-21.5x2 boiler TGM-84 st. No. 4 CHPP-9, a plate-type noise suppressor was installed on the straight vertical section of the boiler flue behind the smoke exhausters before entering the chimney at an elevation of 23.63 m.

The plate noise silencer for the flue duct of the TGM TETs-9 boiler is a two-stage design.

Each muffler stage consists of five plates 200 mm thick and 2500 mm long, placed evenly in a gas duct measuring 3750x2150 mm. The distance between the plates is 550 mm, the distance between the outer plates and the wall of the flue is 275 mm. With this placement of the plates, the relative flow area is 73.3%. The length of one stage of the muffler without fairings is 2500 mm, the distance between the stages of the muffler is 2000 mm, inside the plates there is a non-flammable, non-hygroscopic sound-absorbing material, which is protected from blowing by fiberglass and perforated metal sheets. The muffler has aerodynamic drag about 130 Pa. The weight of the muffler structure is about 2.7 tons. The acoustic efficiency of the muffler, according to test results, is 22-24 dB at geometric mean frequencies of 1000-8000 Hz.

An example of a comprehensive development of noise reduction measures is the development of MPEI to reduce noise from smoke exhausters at HPP-1 of Mosenergo OJSC. Here, high demands were placed on the aerodynamic resistance of the silencers, which had to be placed in the station’s existing gas ducts.

To reduce the noise of gas paths of boilers Art. No. 6, 7 GES-1, a branch of Mosenergo OJSC, MPEI has developed an entire noise reduction system. The noise reduction system consists of the following elements: a plate muffler, gas path turns lined with sound-absorbing material, a separating sound-absorbing partition and a ramp. The presence of a dividing sound-absorbing partition, a ramp and sound-absorbing lining of the turns of the boiler flues, in addition to reducing noise levels, helps to reduce the aerodynamic resistance of the gas paths of power boilers st. No. 6, 7 as a result of eliminating the collision of flue gas flows at the point of their connection, organizing smoother turns of flue gases in gas paths. Aerodynamic measurements showed that the total aerodynamic resistance of the gas paths of the boilers behind the smoke exhausters practically did not increase due to the installation of a noise suppression system. The total weight of the noise reduction system was about 2.23 tons.

Experience in reducing noise levels from air intakes of forced-air boiler fans is given in. The article discusses examples of reducing the noise of boiler air intakes using silencers designed by MPEI. Here are the mufflers for the air intake of the VDN-25x2K blower fan of the BKZ-420-140 NGM boiler st. No. 10 CHPP-12 of Mosenergo OJSC and hot water boilers through underground mines (using the example of boilers

PTVM-120 RTS "Yuzhnoye Butovo") and through channels located in the wall of the boiler house building (using the example of boilers PTVM-30 RTS "Solntsevo"). The first two cases of air duct layout are quite typical for energy and hot water boilers, and a feature of the third case is the absence of areas where a muffler can be installed and high air flow rates in the ducts.

Measures to reduce noise were developed and implemented in 2009 using sound-absorbing screens from four communication transformers of the TC TN-63000/110 type at TPP-16 of Mosenergo OJSC. Sound-absorbing screens are installed at a distance of 3 m from transformers. The height of each sound-absorbing screen is 4.5 m, and the length varies from 8 to 11 m. The sound-absorbing screen consists of separate panels installed in special racks. Steel panels with sound-absorbing cladding are used as screen panels. The panel on the front side is covered with a corrugated metal sheet, and on the side of the transformers - with a perforated metal sheet with a perforation coefficient of 25%. Inside the screen panels there is a non-flammable, non-hygroscopic sound-absorbing material.

Test results showed that sound pressure levels after installing the screen decreased at control points to 10-12 dB.

Currently, projects have been developed to reduce noise from cooling towers and transformers at TPP-23 and from cooling towers at TPP-16 of Mosenergo OJSC using screens.

The active introduction of MPEI noise silencers for hot water boilers continued. In the last three years alone, silencers have been installed on boilers PTVM-50, PTVM-60, PTVM-100 and PTVM-120 at RTS Rublevo, Strogino, Kozhukhovo, Volkhonka-ZIL, Biryulyovo, Khimki -Khovrino”, “Red Builder”, “Chertanovo”, “Tushino-1”, “Tushino-2”, “Tushino-5”, “Novomoskovskaya”, “Babushkinskaya-1”, “Babushkinskaya-2”, “Krasnaya Presnya” ", KTS-11, KTS-18, KTS-24, Moscow, etc.

Tests of all installed silencers have shown high acoustic efficiency and reliability, which is confirmed by implementation certificates. Currently, more than 200 silencers are in use.

The introduction of MPEI silencers continues.

In 2009, an agreement was concluded in the field of supply of comprehensive solutions to reduce noise impact from power equipment between MPEI and the Central Repair Plant (TsRMZ Moscow). This will make it possible to more widely introduce MPEI developments at the country’s energy facilities. CONCLUSION

The developed complex of MPEI mufflers to reduce noise from various power equipment has shown the necessary acoustic efficiency and takes into account the specifics of work at power facilities. The mufflers have undergone long-term operational testing.

The considered experience of their use allows us to recommend MPEI silencers for widespread use at energy facilities in the country.

REFERENCES

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2. Grigoryan F.E., Pertsovsky E.A. Calculation and design of noise suppressors for power plants. L.: Energy, 1980. - 120 p.

3. Fighting noise in production / ed. E.Ya. Yudina. M.: Mechanical engineering. 1985. - 400 p.

4. Tupov V.B. Reducing noise from power equipment. M.: MPEI Publishing House. 2005. - 232 p.

5. Tupov V.B. Noise impact of energy facilities on the environment and methods for its reduction. In the reference book: “Industrial Thermal Power Engineering and Heat Engineering” / edited by: A.V. Klimenko, V.M. Zorina, MPEI Publishing House, 2004. T. 4. P. 594-598.

6. Tupov V.B. Noise from power equipment and ways to reduce it. In the textbook: “Ecology of Energy”. M.: MPEI Publishing House, 2003. pp. 365-369.

7. Tupov V.B. Reducing noise levels from power equipment. Modern environmental technologies in the electric power industry: Information collection / ed. V.Ya. Putilova. M.: MPEI Publishing House, 2007, pp. 251-265.

8. Marchenko M.E., Permyakov A.B. Modern noise suppression systems for the discharge of large steam flows into the atmosphere // Thermal power engineering. 2007. No. 6. pp. 34-37.

9. Lukashchuk V.N. Noise during blowing of steam superheaters and development of measures to reduce its impact on the environment: diss... cand. those. Sciences: 05.14.14. M., 1988. 145 p.

10. Yablonik L.R. Noise protection structures of turbine and boiler equipment: theory and calculation: diss. ...doc. those. Sci. St. Petersburg, 2004. 398 p.

11. Steam emission noise suppressor (options): Patent

for utility model 51673 RF. Application No. 2005132019. Application 10.18.2005 / V.B. Tupov, D.V. Chugunkov. - 4 s: ill.

12. Tupov V.B., Chugunkov D.V. Steam emission noise suppressor // Electric stations. 2006. No. 8. pp. 41-45.

13. Tupov V.B., Chugunkov D.V. The use of noise suppressors when discharging steam into the atmosphere/Ulovoe in the Russian electric power industry. 2007. No. 12. P.41-49

14. Tupov V.B., Chugunkov D.V. Noise silencers on steam discharges of power boilers // Thermal power engineering. 2009. No. 8. P.34-37.

15. Tupov V.B., Chugunkov D.V., Semin S.A. Reducing noise from exhaust ducts of gas turbine units with waste heat boilers // Thermal power engineering. 2009. No. 1. P. 24-27.

16. Tupov V.B., Krasnov V.I. Experience in reducing the noise level from air intakes of blower fans of boilers // Thermal power engineering. 2005. No. 5. pp. 24-27

17. Tupov V.B. Noise problem from power stations in Moscow // 9th International Congress on Sound and Vibration Orlando, Florida, USA, 8-11, July 2002.P. 488-496.

18. Tupov V.B. Noise reduction from blow fans of hot-water boilers//ll th International Congress on Sound and Vibration, St. Petersburg, 5-8 July 2004. P. 2405-2410.

19. Tupov V.B. Methods for reducing noise from water heating boilers RTS // Thermal power engineering. No. 1. 1993. pp. 45-48.

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21. Lomakin B.V., Tupov V.B. Experience of noise reduction in the area adjacent to CHPP-26 // Electric stations. 2004. No. 3. pp. 30-32.

22. Tupov V.B., Krasnov V.I. Problems of reducing noise from energy facilities during expansion and modernization // I specialized thematic exhibition “Ecology in the Energy Industry-2004”: Sat. report Moscow, All-Russian Exhibition Center, October 26-29, 2004. M., 2004. P. 152-154.

23. Tupov V.B. Experience in reducing noise from power plants/Y1 All-Russian scientific and practical conference with international participation “Protection of the population from increased noise exposure”, March 17-19, 2009 St. Petersburg, pp. 190-199.

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Due to the fact that noise in modern power plants, as a rule, exceeds permissible levels, noise suppression work has been widely deployed in recent years.
There are three main methods for reducing industrial noise: reducing noise at the source; reduction of noise along its propagation paths; architectural, construction and planning solutions.
The method of reducing noise at the source of its occurrence is to improve the design of the source and change the technological process. The most effective use of this method is when developing new power equipment. Recommendations for reducing noise at the source are given in § 2-2.
To soundproof various rooms of a power plant (especially the machine and boiler rooms), as the most noisy ones, construction solutions are used: thickening the external walls of buildings, using double-glazed windows, hollow glass blocks, double doors, multi-layer acoustic panels, sealing windows, doors, openings, making the right choice places of air intake and exhaust of ventilation units. It is also necessary to ensure good sound insulation between the machine room and basements, carefully sealing all holes and openings.
When designing a machine room, avoid Not large premises with smooth, non-sound-absorbing walls, ceiling, and floor. Covering walls with sound-absorbing materials (SAM) can reduce noise levels by approximately 6-7 dB in medium-sized rooms (3000-5000 m3). For large rooms, the cost-effectiveness of this method becomes debatable.
Some authors, such as G. Koch and H. Schmidt (Germany), as well as R. French (USA), believe that acoustic treatment of the walls and ceilings of station premises is not very effective (1-2 dB). Data published by the French Energy Authority (EDF) show the promise of this noise reduction method. Treatment of ceilings and walls in boiler rooms at the Saint-Depis and Chenevier power plants made it possible to achieve a sound reduction of 7-10 dB A.
At stations, separate soundproofed control panels are often built, the sound level in which does not exceed 50-60 dB A, which meets the requirements of GOST 12.1.003-76. Service personnel spend 80-90% of their working time in them.
Sometimes acoustic booths are installed in machine rooms to accommodate service personnel(on-duty electricians, etc.). These soundproofing cabins are an independent frame on supports, to which the floor, ceiling, and walls are attached. Cabin windows and doors must have increased sound insulation(double doors, double glass). For ventilation it is provided ventilation unit with silencers at the air inlet and outlet.
If it is necessary to have a quick exit from the cabin, it is made semi-closed, that is, one of the walls is missing. At the same time, the acoustic efficiency of the cabin is reduced, but there is no need for ventilation. According to the data, the maximum value of average sound insulation for semi-closed cabins is 12-14 dB.
The use of individual closed or semi-closed cabins in station premises can be classified as individual means of protecting operating personnel from noise. Personal protective equipment also includes various types earbuds and headphones. The acoustic efficiency of earbuds and, especially, headphones in the high frequency range is quite high and amounts to at least 20 dB. The disadvantages of these products are that, along with noise, the level of useful signals, commands, etc. decreases, and skin irritation is also possible, mainly at elevated temperatures environment. However, it is recommended to use earbuds and headphones when working in environments with noise levels that exceed acceptable levels, especially in the high frequency range. Of course, it is advisable to use them for short-term exits from soundproof cabins or control panels into high-noise areas.

One of the ways to reduce noise along the paths of its propagation in station premises is acoustic screens. Acoustic screens are made of thin sheet metal or other dense material, which may have sound-absorbing lining on one or both sides. Typically, acoustic screens are small in size and provide local reductions in direct sound from a noise source without significantly affecting the level of reflected sound in the room. In this case, the acoustic efficiency is not very high and depends mainly on the ratio of direct and reflected sound at the design point. Increasing the acoustic efficiency of screens can be achieved by increasing their area, which should be at least 25-30% of the cross-sectional area of ​​the room enclosures in the plane of the screen. In this case, the effectiveness of the screen increases due to a decrease in the energy density of reflected sound in the screened part of the room. Application of screens large sizes It also makes it possible to significantly increase the number of workplaces where noise reduction is ensured.

The most effective use of screens is in conjunction with the installation of sound-absorbing linings on the enclosing surfaces of premises. A detailed description of methods for calculating acoustic efficiency and issues of designing screens is given in and
To reduce noise throughout the machine room, installations emitting intense sound are covered with casings. Soundproofing enclosures are usually made of sheet metal lined with the inside of the PZM. The surfaces of the installations can be completely or partially sheathed with soundproofing material.
According to data presented by American noise reduction experts at the International Energy Conference in 1969, the complete equipment of turbine units high power(500-1000 MW) soundproofing casings can reduce the level of emitted sound by 23-28 dB A. When placing turbine units in special insulated boxes, the efficiency increases to 28-34 dB A.
The range of materials used for sound insulation is very wide and, for example, for the insulation of 143 steam units that were introduced in the USA after 1971, it is distributed as follows: aluminum - 30%, sheet steel - 27%, gelbest - 18%, asbestos cement - 11%, brick - 10%, porcelain with external coating - 9%, concrete - 4%.
The following materials are used in prefabricated acoustic panels: soundproofing - steel, aluminum, lead; sound-absorbing - polystyrene foam, mineral wool, fiberglass; damping - bitumen compounds; sealing materials - rubber, putty, plastics.
Polyurethane foam, fiberglass, sheet lead, and vinyl reinforced with lead powder are widely used.
The Swiss company VVS, in order to reduce the noise of the brush apparatus and exciters of high-power turbo units, covers them with a continuous protective casing with a thick layer of sound-absorbing material, into the walls of which mufflers are built in at the inlet and outlet of the cooling air.

The design of the casing provides easy access to these units for carrying out current repairs. As research by this company has shown, the soundproofing effect of the casing of the front part of the turbine is most pronounced at high frequencies (6-10 kHz), where it is 13-20 dB, at low frequencies (50-100 Hz) it is insignificant - up to 2-3 dB .

Rice. 2-10. Sound pressure levels at a distance of 1 m from the body of a gas turbine unit type GTK-10-Z
1- with decorative casing; 2- with body removed

Particular attention should be paid to sound insulation at power plants with gas turbine drives. Calculations indicate that at gas turbine power plants the placement of gas turbine engines (GTE) and compressors is most economical in individual boxes (if the number of GTEs is less than five). When placed in common building With four gas turbine engines, the construction cost of the building is 5% higher than when using individual boxes, and with two gas turbine engines, the difference in cost is 28%. Therefore, when there are more than five installations, it is more economical to place them in a common building. For example, Westinghouse installs five 501-AA gas turbines in one acoustically isolated building.

Typically, individual boxes use sheet metal panels with sound-absorbing lining on the inside. The sound-absorbing lining can be made of mineral wool or semi-rigid mineral wool slabs in a fiberglass shell and covered on the side of the noise source with a perforated sheet or metal mesh. The panels are connected to each other with bolts, and at the joints there are elastic gaskets.
Multilayer panels made of internal perforated steel and external lead sheets, between which a porous sound-absorbing material is placed, are very effective, used abroad. Panels with a multi-layer internal lining made of a layer of vinyl reinforced with lead powder and located between two layers of fiberglass - an internal one, 50 mm thick, and an external one, 25 mm thick - are also used.
However, even the simplest decorative and soundproofing cladding provides a significant reduction in background noise in machine rooms. In Fig. Figures 2-10 show sound pressure levels in octave frequency bands, measured at a distance of 1 m from the surface of the decorative casing of a GTK-10-3 type gas pumping unit. For comparison, the noise spectrum measured with the casing removed at the same points is also shown. It can be seen that the effect of a casing made of a steel sheet 1 mm thick, lined inside with glass fiber 10 mm thick, is 10-15 dB in the high-frequency region of the spectrum. The measurements were carried out in a workshop built according to standard project, where 6 GTK-10-3 units are installed, covered with decorative cladding.
A common and very important problem for energy enterprises of any type is the sound insulation of pipelines. Pipelines modern installations form a complex extended system with a huge surface of heat and sound radiation.

Rice. 2-11. Sound insulation of a gas pipeline at the Kirchleigeri thermal power plant: a - insulation diagram; b - components of a multilayer panel
1- metal cladding from sheet steel; 2- mats made of stone wool 20 mm thick; 3- aluminum foil; 4- multi-layer panel 20 mm thick (weight I m2 is 10.5 kg); 5-bituminized felt; 6-layers of thermal insulation; 7-layer foam

This is especially true for power plants with a combined cycle, which sometimes have a complex branched network of pipelines and a system of gates.

To reduce the noise of pipelines transporting highly disturbed flows (for example, in areas behind pressure reducing valves), enhanced sound insulation shown in Fig. 2-11.
The sound insulating effect of such a coating is about 30 dB A (reduction in sound level compared to a “bare” pipeline).
For lining pipelines large diameter Multilayer thermal and sound insulation is used, which is strengthened with the help of ribs and hooks welded to the insulated surface.
The insulation consists of a layer of mastic sovelite insulation 40-60 mm thick, on top of which a wire armor mesh 15-25 mm thick is laid. The mesh serves to strengthen the sovelite layer and create air gap. The outer layer is formed by mineral wool mats 40-50 mm thick, on top of which a layer of asbestos-cement plaster 15-20 mm thick is applied (80% grade 6-7 asbestos and 20% grade 300 cement). This layer is covered (pasted) with some technical fabric. If necessary, the surface is painted. This method of sound insulation using previously existing thermal insulation elements can significantly reduce noise. The additional costs associated with the introduction of new sound insulation elements are negligible compared to conventional thermal insulation.
As already noted, the most intense is the aerodynamic noise that occurs during the operation of fans, smoke exhausters, gas turbine and combined cycle units, and discharge devices (purge lines, safety lines, lines of anti-surge valves of gas turbine compressors). This also includes ROU.

To limit the spread of such noise along the flow of the transported medium and its release into the surrounding atmosphere, noise suppressors are used. Silencers occupy important place in the general system of measures to reduce noise at energy enterprises, because through intake or discharge devices, sound from working cavities can be directly transmitted to the surrounding atmosphere, creating the highest sound pressure levels (compared to other sources of sound emission). It is also useful to limit the spread of noise throughout the transported medium in order to prevent excessive penetration through the walls of the pipeline to the outside by installing noise mufflers (for example, the section of the pipeline behind the pressure reducing valve).
On modern powerful steam turbine units, noise suppressors are installed at the suction of blower fans. In this case, the pressure drop is strictly limited by an upper limit of the order of 50-f-100 Pa. The required efficiency of these mufflers is usually from 15 to 25 dB in terms of installation effect in the spectrum region of 200-1000 Hz.
Thus, at the Robinson TPP (USA) with a capacity of 900 MW (two blocks of 450 MW each), to reduce the noise of blower fans with a capacity of 832,000 m3/h, suction silencers were installed. The muffler consists of a housing (steel sheets 4.76 mm thick), in which a grid of sound-absorbing plates is located. The body of each plate is made of perforated galvanized steel sheets. Sound-absorbing material is mineral wool protected by fiberglass.
The Coppers company produces standard sound-attenuating blocks used in fan silencers used for drying pulverized coal, supplying air to boiler burners, and ventilating rooms.
The noise of smoke exhausters often poses a significant danger, since it can escape through the chimney into the atmosphere and spread over considerable distances.
For example, at the Kirchlengern thermal power plant (Germany), the sound level near the chimney was 107 dB at a frequency of 500-1000 Hz. In this regard, it was decided to install an active silencer in the chimney of the boiler building (Fig. 2-12). The muffler consists of twenty scenes 1 with a diameter of 0.32 m and a length of 7.5 m. Taking into account the complexity of transportation and installation, the scenes along the length are divided into parts that are connected to each other and secured with bolts to the supporting structure. The slide consists of a body made of sheet steel and an absorber (mineral wool) protected by fiberglass. After installing the muffler, the sound level at the chimney was 89 dB A.
The complex task of reducing gas turbine noise requires an integrated approach. Below is an example of a set of measures to combat gas turbine noise, an essential part of which are noise suppressors in gas-air ducts.
To reduce the noise level of a gas turbine unit with a 17.5 MW Olympus 201 turbojet engine, an analysis of the required degree of noise attenuation of the installation was carried out. It was required that the octave noise spectrum measured at a distance of 90 m from the base of the steel chimney should not exceed PS-50. The layout shown in Fig. 2-13, provides attenuation of gas turbine suction noise by various elements (dB):

A two-stage muffler is installed at the air inlet to the gas turbine unit. plate type with high and low frequency steps. The muffler stages are installed after the cycle air filter.
An annular low-frequency muffler is installed on the gas turbine exhaust. Results of the analysis of the noise field of a gas turbine engine with a turbojet engine at the exhaust before and after installing a muffler (dB):

To reduce noise and vibration, the gas turbine generator was enclosed in a casing, and silencers were installed at the air inlet of the ventilation system. As a result, the noise measured at a distance of 90 m was:

American companies Solar, General Electric, and the Japanese company Hitachi use similar noise suppression systems for their gas turbine units.
For high-power gas turbines, mufflers at the air intake are often very bulky and complex engineering structures. An example is the noise suppression system at the Vahr gas turbine power plant (Germany), on which two gas turbines from the Brown-Boveri company with a capacity of 25 MW each are installed.

Rice. 2-12. Installation of a silencer in the chimney of the Kirchlängerä thermal power plant

Rice. 2-13. Noise suppression system for an industrial gas turbine unit with an aviation gas turbine engine as a gas generator
1- outer sound-absorbing ring; 2- internal sound-absorbing ring; 3- bypass cover; 4 - air filter; 5- turbine exhaust; 6- plates of high-frequency suction muffler; 7-plates of low-frequency intake muffler

The station is located in the central part of the populated area. A muffler consisting of three sequential stages is installed at the gas turbine suction. The first-stage sound-absorbing material, designed to dampen low-frequency noise, is mineral wool covered with synthetic fabric and protected by perforated metal sheets. The second stage is similar to the first, but differs in smaller gaps between the plates. Third stage
consists of metal sheets coated with sound-absorbing material and serves to absorb high-frequency noise. After installing a muffler, the noise of the power plant, even at night, did not exceed the norm accepted for this area (45 dB L).
Similar complex two-stage mufflers are installed at a number of powerful domestic installations, for example, at the Krasnodar Thermal Power Plant (GT-100-750), Nevinnomysskaya State District Power Plant (PGU-200). A description of their design is given in § 6-2.
The cost of noise suppression measures at these stations amounted to 1.0-2.0% of the total cost of the station or about 6% of the cost of the gas turbine plant itself. In addition, the use of silencers is associated with a certain loss of power and efficiency. The construction of silencers requires the use of large quantities of expensive materials and is quite labor-intensive. Therefore, issues of optimization of noise suppressor designs become especially important, which is impossible without knowledge of the most advanced calculation methods and the theoretical basis of these methods.

Date: 12/12/2015

Boiler rooms make a lot of noise. They have many elements that make sounds: pumps, fans, pumps and other mechanisms. In principle, working in industry, with industrial equipment, one way or another forces a specialist to deal with noise, and it is not yet possible to make the units completely silent. But you can make them much less loud.

How to reduce the noise of a boiler room when designing

Very strict requirements are imposed on the noise level of electrical and thermal power facilities, especially if the designated facilities are located within the city. A boiler room is just a heat power facility, and even being compact, it can cause significant discomfort to others.

It is impossible to remove boiler installations from the urban environment. All that remains is to work out the project in such a way that the noise level in the finished boiler room is reduced, and also to use all kinds of auxiliary means.

So, there are two types of noise in a boiler room: airborne and structure-borne. Hull noise is the mechanical vibrations that occur during equipment operation, and airborne noise is the sounds that invariably occur when gas is burned. Fan burners, which are equipped with gas exhaust systems, also make noise.

To prevent the boiler room from vibrating during operation, vibration compensators are installed in it.

When designing, it is necessary to take into account the noise level of the block boiler house and reduce it, first of all, by design means. If this is not possible, the boiler room is equipped with specialized mechanisms for noise suppression.

Means for reducing noise in the boiler room

The three main means of reducing noise are:

• sound-absorbing stands;
• flue gas noise suppressors;
• burner casings.

The stand helps reduce mechanical noise from the boiler during operation. It is done completely individually, according to the specific parameters of the boiler - its weight and dimensions. The stands do not come with the boiler; they must be purchased separately.

Silencers reduce the level of vibration in chimneys and the acoustic load, which harms both people and equipment. Silencers are divided into several types: firstly, passive or adsorption models, which not only “muffle” noise, but also convert vibration energy into heat; secondly, these are active silencers - they “catch” noise and send a counter signal opposite in phase.