CN105351911A - Noise control method of built or prebuilt target power plant afterheat boiler - Google Patents

Abstract

The invention discloses a noise control method of a built or prebuilt target power plant afterheat boiler. The noise control method comprises the following steps: actual noise parameters of a built power plant under the condition of not performing the noise treatment are actually measured, a reference radiation sound intensity measurement value of a typical part is obtained, and a reference wall sound reduction index and a reference sound transmission loss are calculated; a model of a target power plant is built, and a target wall sound reduction index and a reference sound transmission loss are calculated; and a radiation sound intensity predicted value of the typical part of the target power plant is obtained according to the numerical values, contributions of sound sources in all selected positions to a whole target radiation sound field are analyzed, positions required to be provided with silencers and needed noise reduction indexes are obtained, and corresponding silencing equipment is designed. The method obtains the setting positions and the noise reduction indexes of the silencing equipment according to the conditions of the built power plant before the afterheat boiler is not built or dose not finish the establishment, and directly installs the silencing equipment in building to reduce the difficulty.

Description

Noise control method for waste heat boiler of built or pre-built target power plant

Technical Field

The invention relates to the technical field of power plants, in particular to a noise control method for a waste heat boiler of a target power plant under construction or pre-construction.

Background

The power plant is provided with factory building, exhaust-heat boiler usually, is equipped with gas turbine unit, generating set etc. in the factory building, and when the noise transmitted exhaust-heat boiler department, because exhaust-heat boiler is in outdoor, the noise can produce very big influence to nearby residential environment, so the law and regulation all has relevant regulation to the control of power plant's noise.

At present, there are two main ways to the noise control of the exhaust-heat boiler of the power plant:

firstly, a silencer is additionally arranged at the main position of a power plant sound source;

secondly, a sound insulation material is additionally arranged on the outer wall of the power plant.

However, the above methods all have corresponding technical problems:

the first scheme is as follows:

the exhaust-heat boiler of power plant and annex (including chimney etc.) belong to non-detachable, when needs carry out the amortization to it, need set up amortization equipment in its inside, however, the inner space is not easily the construction operation, and constructor's safety also is difficult to guarantee.

Based on the above, most of the built power plants do not adopt silencer equipment at present, but adopt a scheme two.

Scheme II:

the sound insulation material is fully arranged, so that higher cost is required; moreover, even if sound insulation materials with good sound insulation effects are arranged on the outer wall, the sound attenuation effect is not ideal based on the multi-directional diffusion of sound. In particular, with the increasingly stringent national regulations for noise control, this solution is not satisfactory.

In view of the above, it is necessary to provide a method that can be easily implemented and reduce the noise of the exhaust-heat boiler of the power plant as much as possible, which is a technical problem to be solved by those skilled in the art.

Disclosure of Invention

In order to solve the technical problems, the invention aims to provide a noise control method for a waste heat boiler of a built or pre-built target power plant, which can reduce the noise of the waste heat boiler of the power plant as much as possible and is easy to implement.

The invention provides a noise control method of a waste heat boiler of a target power plant under construction or pre-construction, which comprises the following steps:

selecting an established power plant as a reference power plant, actually measuring actual noise parameters under the condition that internal noise control is not carried out, and obtaining a reference radiation sound intensity measured value L of a typical part_ref；

Establishing a model of a reference power plant, and calculating a reference wall sound insulation L of a waste heat boiler area of the reference power plant_wal-lrefReference sound transmission loss L_cavity-ref；

Establishing a model of a target power plant, and calculating a target wall sound insulation L of a waste heat boiler area of the target power plant_wal-tlargetTarget sound transmission loss L_{cavity-target}；

Obtaining a predicted value L of radiation sound intensity of a typical part of a target power plant_target：

L_target＝L_ref+(Δ_source-Δ_cavity-Δ_wall)；

Wherein,

Δ_source＝L_{source-target}-L_source-ref；

Δ_cavity＝L_{cavity-target}-L_cavity-ref；

Δ_wall＝L_wall-target-L_wall-ref；

L_{source-target}、L_source-refrespectively representing the furnace noise values of a target power plant and a reference power plant;

according to the predicted value of the radiation sound intensity of the typical part of the target power plant, an integral target radiation sound field of the target power plant is established, a plurality of independent target radiation sound fields corresponding to the selected positions are established, so that the contribution of sound sources at the selected positions to the integral target radiation sound field is analyzed, the positions where the silencers need to be installed and the required silencing amount are obtained according to the contribution, and corresponding silencing equipment is designed.

Alternatively,

calculating to obtain the eddy noise sound power of the rest thermal boilers according to the model of the target power plant, obtaining the noise sound power of the gas exhauster according to the delivery value of the gas exhauster, and obtaining the main noise sound source of the waste heat boiler through comparative analysis;

said L_{sourc-etarget}、L_source-refAnd respectively selecting main noise sources.

Alternatively,

and analyzing the main noise source of the waste heat boiler according to the model of the reference power plant so as to compare the main noise source with the analysis result of the target power plant and verify the analysis result of the main noise source.

Optionally, the position with the largest contribution to the radiated sound field is selected as the position where the muffling apparatus is installed.

Optionally, from a reference radiated sound intensity measurement L_refAnd establishing an integral reference radiation sound field of the reference power plant and a plurality of independent reference radiation sound fields at selected positions so as to compare the integral reference radiation sound field with the independent target radiation sound field and verify the distribution condition of the radiation sound fields.

Optionally, the selected locations include waste heat boiler walls, waste heat boiler and chimney connection sections, horizontal flue external walls, chimney exhaust ports, units and main buildings.

Optionally, the target sound transmission loss and the reference sound transmission loss both include a cavity sound transmission loss, and the cavity sound transmission loss is calculated as follows:

and establishing a local tube array sound intensity model of a single heat exchange tube layer in the waste heat boiler, acquiring corresponding local sound intensity sound transmission loss, and superposing the sound transmission loss of each tube heat exchange tube layer in the waste heat boiler to acquire the sound transmission loss of the furnace chamber.

Optionally, the superposed value of the sound transmission loss is corrected according to the sectional area changes of the horizontal flue, the furnace chamber of the waste heat boiler, the connecting section of the waste heat boiler and the chimney, and/or the temperature change in the furnace, so as to obtain the sound transmission loss of the furnace chamber.

Optionally, the typical part is selected from a heat exchange tube set, a horizontal flue, a chimney barrel body and a chimney opening in a furnace cavity of the waste heat boiler.

Optionally, the muffling apparatus is a resistive muffler, and includes a plurality of vertically arranged muffling sheets;

the noise reduction sheet is designed as follows: the silencer is distributed at the installation position in a fan shape, and the thickness of the silencing pieces at two sides of the silencer is smaller than that of the rest silencing pieces.

According to the noise control method, the position where the silencing equipment is to be arranged and the corresponding silencing quantity can be obtained according to the condition of the built power plant before the waste heat boiler of the power plant is not built or is not built, so that the silencing equipment is directly arranged and installed when the waste heat boiler is constructed, the situation that the silencing equipment is arranged after the waste heat boiler of the power plant is built can be avoided, the difficulty of arranging the silencing equipment is reduced, silencing measures are easy to implement, and the safety of workers is improved. In addition, the more important significance of the control method is that the power plant under construction or pre-construction which is consistent with the model of the waste heat boiler of the target power plant and is equipped with the waste heat boiler is not required to be analyzed and calculated, the analysis result of the scheme can be directly adopted to configure the silencing equipment, and therefore the design efficiency is greatly improved.

Drawings

FIG. 1 is a flow chart of one embodiment of a method for controlling noise of a waste heat boiler of a target power plant according to the present invention;

FIG. 2 is a schematic sectional view of a preheating boiler according to the present embodiment of the present invention;

FIG. 3-1 is a diagram of a model of a target power plant in an embodiment of the invention;

3-2 is a schematic plan view of a plurality of stations arranged on a target power plant model in an embodiment of the invention;

FIG. 4 is a schematic diagram of a resistive muffler installed at a connecting section of a waste heat boiler and a chimney according to an embodiment of the invention;

FIG. 5 is an enlarged, fragmentary schematic view of the resistive muffler of FIG. 4, particularly illustrating the left-hand portion of FIG. 4;

FIG. 6 is a schematic illustration of the configuration of the resistive muffler facing of FIG. 4;

FIG. 7 is a radiation sound field distribution diagram of the whole model of the target power plant in FIG. 3 after the resistive muffler is installed;

FIG. 8 is a comparison of the acoustic power of the exhaust noise of the target power plant gas turbine and the acoustic power of the eddy current noise in the furnace according to an embodiment of the present invention.

In the figure:

11 chimneys, 12 waste heat boiler and chimney connecting sections, 13 waste heat boiler, 14 horizontal flues, 15 main factory buildings, 100 factory boundaries, 200 resistive mufflers, 201 perforated plates, 202 glass cloth and 203 sound absorbing materials

Detailed Description

In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

Referring to fig. 1, fig. 1 is a flowchart illustrating a method for controlling noise of a waste heat boiler of a power plant according to an embodiment of the present invention.

The target power plant is a power plant which is under construction or pre-constructed, namely the power plant is not constructed or infrastructure is constructed, but a waste heat boiler, a chimney and the like are not constructed or are not constructed and completed, and the setting of a noise elimination device is not hindered; the built power plant is an established entity power plant.

The noise control method comprises the following steps:

s10, selecting the built power plant as a reference power plant, obtaining actual noise parameters of the power plant without internal noise control, and obtaining a reference radiation sound intensity measured value L of a typical part_ref；

Here, the fact that the internal noise control is not performed means that the interior of the exhaust heat boiler is not subjected to the noise reduction treatment. As described in the background art, when the sound insulation material is additionally arranged on the outer wall of the factory floor, the acquisition of the actual noise parameters is not hindered, and the noise control is not performed; for the waste heat boiler provided with the silencing equipment, corresponding noise parameters are inevitably recorded before the setting, and the noise parameters can be obtained as actual noise parameters; and for the condition without any noise treatment measures, the measurement can be directly obtained.

A plurality of groups of heat exchange pipes are arranged in the waste heat boiler, and each heat exchange pipe group can be called as a module. The typical positions can be selected from a plurality of modules (such as modules 1-6 described below) of the waste heat boiler, a horizontal flue, a chimney barrel body and a chimney opening. As described in the background art, the noise of the plant unit is transmitted to the outside through the exhaust-heat boiler and the chimney, so that the typical part belongs to a position with relatively large noise, is representative, and can reflect the actual noise distribution condition of the power plant as truly as possible. The waste heat boiler module is selected, and considering that turbulent noise can be generated when air flow passes through the waste heat boiler module besides the propagation of noise of a plant unit, the influence of the turbulent noise on the noise of the waste heat boiler can be verified by selecting the module.

The selected position can detect the sound pressure of the detected point, and the sound intensity of each detected point is obtained according to the sound pressure calculation and is defined as a reference radiation sound intensity measured value L_ref. In order to make the measuring result more accurate and reliable, two or more sensors can be arranged at each measuring point to obtain an average value, or the output faults of the sensors are compared and judged so as to mutually correct.

In this embodiment, taking an established horizontal boiler power plant as an example, the following data are obtained by performing actual measurement:

TABLE 1 Sound source information octave A weighting sound intensity level

Frequency (Hz)

In the table, sound source information of components such as a gas turbine and a steam turbine other than the boiler is detected at the same time, and is mainly used for assisting in confirming the source and the size of noise of the waste heat boiler.

S20, establishing a model of the reference power plant, and calculating the reference wall sound insulation L of the waste heat boiler area of the reference power plant_wall-refReference sound transmission loss L_cavity-ref；

The waste heat boiler region comprises a horizontal flue connected with the plant, the horizontal flue is sequentially connected with the waste heat boiler, a connecting section of the waste heat boiler and the chimney, and the wall sound insulation quantity L_wall-refCorrespondingly comprises the wall sound insulation amount of the horizontal flue, the waste heat boiler wall sound insulation amount, the cavity sound insulation amount of the connecting section of the waste heat boiler and the chimney and the sound insulation amount of the chimney barrel.

Regarding the reference furnace wall sound insulation:

referring to fig. 2, fig. 2 is a schematic cross-sectional view of a preheating boiler wall according to an embodiment of the present invention.

The furnace wall of the waste heat boiler generally comprises a lining steel plate (the inner side of the wall body), a heat insulation layer (arranged between the inner side and the outer side of the wall body) and a shell steel plate (the outer side of the wall body), and the materials and the thicknesses at different positions are often different. The parameters of the rest of the thermal boiler furnace wall materials can be obtained from the design side of the reference power plant so as to calculate the furnace wall sound insulation amount. In the specific calculation, a person skilled in the art can adopt VirtualLab software to perform simulation calculation on the sound insulation quantity of the furnace wall, and can adopt a step method, namely, the designed furnace wall is divided into a double wall consisting of an inner layer steel plate, an outer layer steel plate and cavity air and a single wall with an independent heat insulation layer, and the double wall and the single wall are superposed to form the total sound insulation quantity after being separately calculated.

It should be noted that, because the inside and outside of the furnace are high-temperature flue gas and room-temperature air respectively, and the acoustic impedances are not the same, when calculating the sound insulation amount of the heat insulation layer, the calculation formula needs to be performedCorrected furnace wall sound insulation L of waste heat boiler_l-wall-refObtained by the following formula:

$L_{1-wall-ref}=10\×\log (\frac{{(1+\frac{R_1}{R_3})}^2}{4}+{\left(\frac{\mathrm{\ω}M}{2R_3}\right)}^2)$

wherein R is₁Acoustic impedance, R, of furnace fumes₃The acoustic impedance of air outside the furnace is represented, M represents the volume weight (mass per unit area) of the heat insulating material, omega represents 2 pi f, and f is frequency.

The furnace wall sound insulation amount is obtained through calculation, the calculation method of the horizontal flue sound insulation amount is consistent with that of the furnace wall of the body, and the structure of the horizontal flue is also consistent with that of the furnace chamber of the body. The chimney body is regarded as single wall sound insulation, the method is consistent with the calculation method of the heat insulation layer, and the calculated value of the wall sound insulation amount is shown in the following table 2.

TABLE 2-1 reference sound insulation of exhaust-heat boiler body wall of power plant

Center frequency (Hz)	31.5	63	125	250	500	1000
							Module 1 to 3(dB)	32.1	52.1	69.1	89.1	109.1	109.1
Module 4 ~ 6(dB)	34.1	49.1	67.1	85.1	105.1	115.1
							Horizontal flue (dB)	30.3	49.7	67.8	86.9	107.1	107.3
Chimney barrel body (dB)	21	27	33	39	45	51

Regarding the reference sound transmission loss, the sound transmission loss of the horizontal flue, the waste heat boiler, the chimney connecting section and the chimney is small and can be ignored, and the sound transmission loss in the furnace cavity can be mainly calculated.

The furnace chamber of the whole waste heat boiler can be seen as a rectangular sound cavity, and due to the fact that the heat exchanger tube layer is arranged inside the rectangular sound cavity, the transmission of sound waves in the furnace can be influenced to a certain degree.

The present embodiment calculates the cavity acoustic loss as follows:

firstly, establishing a local tube array sound intensity model of a single heat exchange tube layer in the waste heat boiler, simulating and calculating sound pressure of an inlet and an outlet in VirtualLab to further obtain corresponding local sound intensity sound transmission loss, and then superposing the sound transmission loss of each tube heat tube layer in the waste heat boiler to obtain reference furnace chamber sound transmission loss L_l-cavity-ref：

$L_{1-cavity-ref}=10\lg \[\frac{(p_{in}+\mathrm{\ρ}c)\stackrel{\‾}{(p_{in}+\mathrm{\ρ}c)}}{4p_{out}\stackrel{\‾}{p_{out}}}\]$

Wherein p is_inSound pressure p at the inlet of the single heat exchange tube layer_outSound pressure at the outlet of the single heat exchange tube layer, rho is air density and c is air speed.

The calculation resources required for establishing the complete in-furnace sound intensity model are overlarge, and the superposition type calculation method can simplify the calculation and ensure the result accessibility.

The calculated sound transmission losses of the tube layers are superposed, so that the sound transmission loss of the whole furnace chamber can be obtained, and the following table is shown:

TABLE 2-2 reference power plant exhaust-heat boiler furnace chamber acoustic transmission loss

Center frequency	31.5	63	125	250	500	1000
							Module 1(dB)	0.3	0.3	0.4	0.6	1.1	1.8
Module 2(dB)	0.7	0.8	0.8	1.1	1.8	3.2
							Module 3(dB)	1.1	1.4	1.9	2.2	2.9	4.4
Module 4(dB)	0.7	0.8	0.8	1.2	1.8	3.2
							Module 5(dB)	0.8	0.8	1.0	1.3	1.9	3.3
Module 6(dB)	0.9	0.9	1.2	1.4	2.2	3.8
							In total (dB)	4.5	5	6.1	7.8	11.7	19.7

It should be noted that the sectional areas of the inlet flue, the furnace chamber, the outlet flue and the chimney of the exhaust-heat boiler may change, which is equivalent to the muffler of the expansion chamber, that is, the sound transmission loss value of the furnace chamber calculated in the above manner is smaller than the actual value, but the error is usually smaller and can be ignored. Of course, according to the specific model of the exhaust-heat boiler, the error may also affect the final calculation result, and in order to more accurately obtain the sound transmission loss data, the value obtained by the calculation may also be corrected. The specific acquisition of the correction value can still calculate the sound transmission loss value caused by the section change according to the sound attenuation amount of the expansion cavity silencer in a simulation mode.

In addition, the temperature gradient change in the furnace also has influence on the sound loss, and the correction value can be obtained by simulation so as to correct.

S30, establishing a model of the target power plant, and calculating the target wall sound insulation L of the waste heat boiler area of the target power plant_wall-targetTarget sound transmission loss L_{cavity-target}；

No matter the target power plant is built or pre-built, the target power plant should be designed with corresponding waste heat boiler types, sizes, materials and the like, common waste heat boilers are divided into horizontal boilers and vertical boilers, and corresponding reference boilers can be selected according to the boiler construction types of the target power plant. In this embodiment, a bedroom boiler is set up as an example, and accordingly, the reference power plant is also a horizontal boiler power plant.

L_wall-target、L_{cavity-target}For the calculation of (2), refer to the above-mentioned L_wall-ref、L_cavity-refAnd (4) calculation and principle consistency. The following table is obtained:

TABLE 3-1 reference sound insulation of exhaust-heat boiler body wall of power plant

Center frequency (Hz)	31.5	63	125	250	500	1000
							Module 1 to 3(dB)	28.2	48.1	64.7	84.6	104.1	104.7
Module 4 ~ 6(dB)	30.1	45.1	63.1	81.1	101.2	111.3
							Horizontal flue (dB)	28.2	48.1	64.7	84.6	104.1	104.7
Chimney barrel body (dB)	21	27	33	39	45	51

TABLE 3-2 target power plant exhaust-heat boiler furnace chamber acoustic transmission loss

Center frequency	31.5	63	125	250	500	1000
							Module 1(dB)	0.4	0.4	0.5	0.8	1.3	2.1
Module 2(dB)	0.8	0.9	0.9	1.3	2.1	3.4
							Module 3(dB)	1.1	1.3	1.6	2.1	2.7	4.1
Module 4(dB)	1.2	1.8	1.8	2.4	2.8	4.4
							Module 5(dB)	1.1	1.2	1.6	1.9	2.9	4.3
Module 6(dB)	1.2	1.2	1.4	2.4	2.7	4.6
							In total (dB)	5.8	6.8	7.8	10.9	14.5	22.9

S40, obtaining a radiation sound intensity predicted value L of the typical part of the target power plant_target：

L_target＝L_ref+(Δ_source-Δ_cavity-Δ_wall)；

Wherein,

Δ_source＝L_{source-target}-L_source-ref；

Δ_cavity＝L_{cavity-target}-L_cavity-ref；

Δ_wall＝L_wall-target-L_wall-ref；

L_{source-target}、L_source-refrespectively representing the furnace noise values of a target power plant and a reference power plant;

in step S10, L has been obtained_ref，Δ_wall、Δ_cavity、Δ_sourceA measure L of radiated sound intensity of a reference power plant for a corrected value relative to the reference power plant_refThe sum of the corrected value and the corrected value can be used as a predicted value L of the radiation sound intensity of the target power plant_target。

The in-furnace noise value can be obtained by calculating according to the following mode:

the noise value in the furnace is the distribution value in the gas engine exhaust noise furnace plus the vortex noise of the heat exchanger.

The high temperature waste gas of gas engine carries out the heat transfer by exhaust-heat boiler, raises the efficiency, and when the high temperature waste gas of gas engine got into exhaust-heat boiler, corresponding high noise also can enter into inside the boiler. The distribution value in the gas engine exhaust noise furnace can be obtained according to the exhaust noise sound power when the gas engine is delivered from a factory, and the eddy current noise of the heat exchanger can be obtained by calculation according to the established model. The furnace noise value of the present embodiment is mainly calculated by the gas engine exhaust noise in-furnace distribution value, and the influence of the vortex noise of the heat exchanger is ignored, as will be described in detail later.

In this embodiment, the exhaust noise acoustic power of the gas engine of the reference power plant and the target power plant is shown in the following table:

TABLE 4-1 reference power plant gas engine exhaust noise sound power level

Frequency (Hz)	31.5	63	125	250	500	1000	2000
								Sound power level (dB)	11	2	-2	0	5	8	20

TABLE 4-2 target Sound Power level of exhaust noise of gas turbine of Power plant

Frequency (Hz)	31.5	63	125	250	500	1000	2000
								Sound power level (dB)	142	144	144	145	146	147	152

From the above data, the corresponding correction values can thus be derived:

TABLE 5-1 correction value for exhaust noise source intensity of gas engine

Frequency (Hz)

31.5

63

125

250

500

1000

2000

Sound power level (dB)

131

142

146

145

141

139

132

TABLE 5-2 corrected value of sound insulation quantity of exhaust-heat boiler body wall

Center frequency (Hz)	31.5	63	125	250	500	1000
							Module 1 to 3(dB)	-3.9	-4	-4.4	-4.5	-5	-4.4
Module 4 ~ 6(dB)	-4	-4	-4	-4	-3.9	-3.8
							Horizontal flue (dB)	-2.1	-1.6	-3.1	-2.3	-3	-2.6
Chimney barrel body (dB)	0	0	0	0	0	0

TABLE 5-3 corrected value of sound transmission loss of furnace chamber of exhaust-heat boiler

Center frequency	31.5	63	125	250	500	1000
							Module 1(dB)	0.1	0.1	0.1	0.2	0.2	0.3
Module 2(dB)	0.1	0.1	0.1	0.2	0.3	0.2
							Module 3(dB)	0	-0.1	-0.3	-0.1	-0.2	-0.3
Module 4(dB)	0.5	1	1	1.2	1	1.2
							Module 5(dB)	0.3	0.4	0.6	0.6	1	1
Module 6(dB)	0.3	0.3	0.2	1	0.5	0.8
							In total (dB)	1.3	1.8	1.7	3.1	2.8	3.2

Obtaining a radiation sound intensity predicted value L of each typical part of the target power plant according to the calculation_targetAs shown in the following table:

TABLE 6 predicted value of radiation sound intensity of typical part of waste heat boiler of target power plant

Center frequency (Hz)	31.5	63	125	250	500	1000	2000
								Module 2(dB (A))	49.9	48.1	43.9	47.0	64.1	64.2	66.8
Module 3(dB (A))	48.7	47.7	42.9	46.4	59.0	60.3	65.6
								Module 4(dB (A))	50.5	46.4	42.0	43.2	55.6	57.5	61.6
Module 5(dB (A))	47.2	43.0	38.1	41.9	53.1	54.9	57.4
								Horizontal flue (dB (A))	48.6	42.5	44.2	45.2	63.9	62.5	73.7
Chimney barrel (dB (A))	53.3	57.9	62.4	64.3	68.1	75.4	79.0
								Chimney port (dB (A))	60.8	66.9	76.6	80.7	80.5	77.3	69.6

S50, establishing an integral target radiation sound field of the target power plant according to the radiation sound intensity predicted value of the typical part of the target power plant, and establishing a plurality of independent target radiation sound fields corresponding to the selected positions so as to analyze the selected position which contributes most to the integral target radiation sound field and obtain the required noise elimination amount;

and after the radiation sound intensity predicted value of each typical part is calculated, a corresponding radiation sound field can be established.

The specific selected positions can comprise a waste heat boiler furnace wall, a waste heat boiler and chimney connecting section, a horizontal flue outer wall, a chimney exhaust port, a unit (comprising a generator set, a gas engine, a steam turbine unit and the like) and a main plant.

A model of a power plant can be established in CadnaA software, and as most of the ground around the waste heat boiler of the power plant is cement ground, the whole calculation area can be set to be total reflection under the condition of error allowance, namely the ground sound absorption coefficient in the model is 0, and corresponding measuring points can be arranged.

3-1, 3-2, FIG. 3-1 is a model diagram of a target power plant; FIG. 3-2 is a schematic plan view of a plurality of stations arranged on a target power plant model in an embodiment of the invention. Wherein, the distances between the measuring points 1 and 2 and the center of the chimney 11 are respectively 50m and 100m, the distances between the measuring points 3 and 5 are both 200m, the distance between every two measuring points 3 and 5 is 30m, and the specific numerical value can be selected according to the scale of the power plant.

The radiation sound field distribution diagram of the whole model of the single waste heat boiler can be obtained through grid calculation. When a plurality of waste heat boilers are provided, corresponding models can be established to obtain corresponding distribution maps.

The predicted sound pressure values at different distances from the center of the waste heat boiler chimney 11 can be obtained through the radiation sound field obtained through simulation analysis, and the table is as follows:

TABLE 7-1 predicted sound pressure values of the measuring points under the action of different sound sources

As can be seen from table 7, for the noise at the measuring point of the chimney 11 plant 100 north to 200m (north is upward direction in fig. 3-2), the sound radiation contribution of the chimney 11 barrel is the largest, and then the influence of the exhaust-heat boiler and chimney connection section 12 and the unit and main plant 15 is not very different among the exhaust-heat boiler 13, the chimney 11 outlet and the horizontal flue 14. Taking the measuring point 3 as an example, the noise contribution of the radiation sound source at each part of the exhaust-heat boiler 13 to the sensitive point (the measuring point) can be seen in the following table:

TABLE 7-2 Acoustic radiation contribution of Sound Source to survey Point 3 at each selected location

Sorting	Selected position (radiation sound source)	Contribution amount (%)
			1	Chimney barrel body	89.88
2	Waste heat boiler	3.92
			3	Chimney exhaust port	2.36
4	Horizontal flue	2.26
			5	Unit and main plant	1.27
6	Connecting section of exhaust-heat boiler and chimney	0.31

According to the above calculation results, a muffler may be provided at the position of the exhaust-heat boiler and stack connection section 12, and the required amount of noise reduction is already obtained by the above model analysis, as shown in the following table:

TABLE 7-3 octave sound pressure level and required amount of sound deadening at the measurement points

And S60, obtaining the parameters of the corresponding silencing equipment installed at the selected position.

After the silencing amount is obtained, parameters such as materials, sizes and the like of silencing equipment needing to be installed can be designed. The silencing equipment in the embodiment adopts the resistive silencer 200, and is particularly arranged in a flue gas channel of the connecting section 12 of the waste heat boiler and the chimney, because of the gravity relationship, the resistive silencer 200 is preferably vertically arranged, and the resistive silencer can effectively eliminate medium-high frequency noise. As described above, the chimney 11 has a large noise, and the resistive muffler 200 is disposed in the flue gas passage to eliminate the noise as much as possible before the noise is transmitted to the chimney 11, so that the noise is greatly reduced.

The resistive muffler 200 may specifically include a plurality of vertically arranged muffling sheets, which can be described with reference to fig. 4, where fig. 4 is a schematic diagram illustrating that the resistive muffler is installed at a connecting section of a waste heat boiler and a chimney in an embodiment of the present invention; FIG. 5 is an enlarged, fragmentary schematic view of the resistive muffler of FIG. 4, particularly illustrating the left-hand portion of FIG. 4; FIG. 6 is a schematic illustration of the resistive muffler facing of FIG. 4.

In this embodiment, the plurality of muffling sheets of the resistive muffler are arranged in a fan shape at the position of the chimney connecting section 12 to adapt to the normal throat setting at the position, and as shown in fig. 4, the muffling sheets on both sides of the resistive muffler 200 are sequentially close to the middle. In addition, for convenience of installation and fixation, the thicknesses of the silencing sheets on two sides can be designed to be smaller than those of the rest silencing sheets.

Can be based on the high frequency failure frequency f_cThe length of the resistive muffler 200 is calculated according to the formula and the formula of the muffling amount, and the number of muffling pieces is designed according to the length.

$f_c=1.85\frac{C}{D}=1.85\frac{331.6+0.6t}{D}\left(Hz\right)$

Wherein C is sound velocity, the flue gas can be treated according to air, the temperature t is 90 ℃, D is the diameter of the cross section of the channel, when the channel is rectangular,(a, h are the side lengths of the rectangular channel, respectively);

${\mathrm{\ΔL}}^{\′}=\frac{3-L}{3}\mathrm{\Δ}L$

wherein, DeltaL is the silencing quantity of a single silencing sheet, and n is the number of octave bands higher than the failure frequency.

In order to increase the life of the resistive muffler 200, the muffling sheet used in this embodiment is provided with a facing, which corresponds to the housing of the resistive muffler 200, the facing includes a layer of glass cloth 202 and a layer of perforated plate 202, and the inside of the facing is a sound absorbing material 203, as shown in fig. 6.

When the mounting structure is designed, in order to facilitate the internal overhaul in the resistive muffler 200 and the flue of the chimney 11 at the later stage, the support steel frame structure of part of the muffling sheets is designed to be movable or detachable so that workers or equipment can pass through the support steel frame structure.

Through calculation and analysis, after the resistive muffler 200 is added in the power plant model, when the simulation is performed again, the noise contribution of each radiation sound source to the measuring points can be obtained, the measuring points are still arranged according to the condition that the resistive muffler 200 is not added, and the measuring points are still exemplified and explained at the moment, as shown in the following table.

TABLE 8 Acoustic radiation contribution of radiated sound source to test point 3 at each selected location after adding resistive muffler

Sorting	Selected position (radiation sound source)	Contribution amount (%)
			1	Chimney barrel body	39.08
2	Waste heat boiler	22.49
			3	Chimney exhaust port	20.51
4	Horizontal flue	12.64
			5	Unit and main plant	3.03
6	Chimney connection section	2.25

Comparing table 7-2, it can be seen that, after the resistive muffler 200 is added, the contribution amounts of the chimney 11 and the exhaust port of the chimney 11 are significantly reduced, and the contribution ratios of other sound sources to the overall sound radiation noise level are correspondingly increased, thus the noise is reduced.

Referring also to fig. 7, fig. 7 is a distribution diagram of a radiation sound field of the whole model of the target power plant of fig. 3 after the resistive muffler is installed.

It can be seen from the figure that the sound pressure value of the sensitive point at 200m of the plant boundary is lower than the class 2 standard in the environmental noise emission standard of the plant boundary of industrial enterprises (GB12348-2008), and the noise at the sensitive point basically meets the standard requirement, thereby achieving a certain noise treatment effect.

In the embodiment, the resistive muffler 200 is arranged at the position which contributes most to the radiation sound field, and it can be known that in order to improve the muffling effect, muffling equipment with corresponding muffling amount can be arranged at other positions, or various comprehensive noise treatment measures such as sound insulation measures, muffling measures, sound absorption measures, damping measures, vibration reduction and the like are adopted.

It is to be noted that, when the furnace noise value is calculated, only the exhaust noise power is used for calculation, and the eddy noise of the heat exchanger is ignored, because the eddy noise has little influence on the furnace noise value through simulation calculation.

The eddy noise of the waste heat boiler is mainly generated by the heat exchange tube inside the waste heat boiler, and the waste heat boiler comprises a high-pressure superheater, a reheater, a high-pressure evaporator, a medium-pressure superheater, a medium-pressure evaporator, a low-pressure superheater and the like. The eddy noise of a single heat exchange tube can be calculated firstly, then the eddy noise of the evaporator, the superheater and the like can be calculated according to the arrangement mode, the number and the like of each heat exchange tube array, and finally the eddy noise of the whole waste heat boiler is obtained through superposition. In this embodiment, according to the parameters of the waste heat boiler of the target power plant, the acoustic power of the eddy current noise in the furnace can be obtained, and then compared with the acoustic power of the exhaust noise of the gas engine, as shown in fig. 8, fig. 8 is a schematic diagram illustrating the comparison between the acoustic power of the exhaust noise of the gas engine of the target power plant and the acoustic power of the eddy current noise in the furnace in the embodiment of the present invention.

Comparative analysis shows that although the eddy current noise has a low-frequency narrow-band characteristic, the eddy current noise is 10dB lower than the exhaust noise of the gas engine, and cannot be a main sound source of the noise in the boiler, so that the radiation sound of the waste heat boiler is mainly determined to be contributed by the exhaust noise of the gas engine.

The significance of this analysis is that on the one hand the calculation of step S40 can be simplified and on the other hand also directions are provided for further noise reduction.

At this time, the main noise source of the exhaust-heat boiler can be analyzed according to the model of the reference power plant, the eddy current noise is calculated by modeling and then compared with the exhaust noise of the gas engine according to the analysis of the target power plant, similarly, the main noise source of the exhaust noise of the gas engine is obtained according to the relevant parameters of the exhaust-heat boiler of the reference power plant in the embodiment, and the analysis result of the main noise source is verified.

Of course, the primary noise source may be verified in other ways than by calculating the eddy current noise as compared to the gas engine exhaust noise. Aiming at a reference power plant, after the sound insulation amount of the furnace wall is calculated, the sound intensity of each typical position (the sound intensity measured at the typical position plus the sound insulation amount of the furnace wall) can be obtained, then the sound intensity of the gas engine exhaust noise at the corresponding typical position is obtained through simulation, and when the distribution trends of the sound intensity are basically consistent, the gas engine exhaust noise can be determined to belong to a main noise sound source.

The reference power plant and the target power plant are used for analyzing main noise sources, the main noise sources and the target power plant can be verified mutually, when the verification result is inconsistent, the fact that deviation possibly occurs in the introduction of parameters, the simulation process and the like is shown, and technical personnel can be guided to correct the deviation so as to avoid the fact that the deviation causes calculation errors of other steps. In addition, the mutual verification result also plays a good example role in the construction of similar waste heat boilers in the future.

In addition, when designing the silencer, the predicted value L according to the radiation sound intensity is required_targetA radiated sound field is established and the position contributing the most to the radiated sound field is analyzed accordingly, so that a muffler is installed therein. Similarly, to avoid the occurrence of a deviation, the measured value L of the radiated sound intensity of the reference power plant may be used_refAnd establishing a reference radiation sound field of a reference power plant, including the radiation sound field of the whole target power plant and the radiation sound fields of a plurality of selected positions, wherein the specific simulation process is basically consistent with the target power plant, and when the specific simulation process is compared with the target radiation sound field, the distribution condition of the radiation sound field is basically consistent.

In fact, the establishment of the main noise source, the determination of the position to be silenced and the silencing amount according to the radiation sound field can be performed by using a reference power plant, because the data of the reference power plant can be actually measured, the obtained result has more guiding significance, and then the corresponding simulation calculation is performed on the target power plant.

The noise control method can obtain the position where the silencing equipment is to be arranged and the corresponding silencing quantity according to the condition of the built power plant before the waste heat boiler of the power plant is not built or is not built, so that the silencing equipment is directly assembled and installed when the waste heat boiler is constructed, the problem that the silencing equipment is arranged after the waste heat boiler of the power plant is built can be avoided, the difficulty of assembling the silencing equipment is reduced, the silencing measures are easy to implement, and the safety of workers is improved. In addition, the more important significance of the control method is that the power plant under construction or pre-construction which is consistent with the model of the waste heat boiler of the target power plant and is equipped with the waste heat boiler is not required to be analyzed and calculated, the analysis result of the scheme can be directly adopted to configure the silencing equipment, and therefore the design efficiency is greatly improved.

The noise control method of the waste heat boiler of the target power plant under construction or pre-construction provided by the invention is described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims (10)

1. A noise control method for a waste heat boiler of a target power plant under construction or pre-construction is characterized by comprising the following steps:

selecting an established power plant as a reference power plant, actually measuring actual noise parameters under the condition that internal noise control is not carried out, and obtaining a reference radiation sound intensity measured value L of a typical part_ref；

Establishing a model of a reference power plant, and calculating a reference wall sound insulation L of a waste heat boiler area of the reference power plant_wal-lrefReference sound transmission loss L_cavity-ref；

Establishing a model of a target power plant, and calculating the target wall sound insulation L of the waste heat boiler area of the power plant_wal-ltargetTarget sound transmission loss L_{cavity-target}；

Obtaining a predicted value L of radiation sound intensity of a typical part of a target power plant_target：

L_target＝L_ref+(Δ_source-Δ_cavity-Δ_wall)；

Wherein,

Δ_source＝L_{source-target}-L_source-ref；

Δ_cavity＝L_{cavity-target}-L_cavity-ref；

Δ_wall＝L_wall-target-L_wall-ref；

L_{source-target}、L_source-refrespectively representing the furnace noise values of a target power plant and a reference power plant;

according to the predicted value of the radiation sound intensity of the typical part of the target power plant, an integral target radiation sound field of the target power plant is established, a plurality of independent target radiation sound fields corresponding to the selected positions are established, so that the contribution of sound sources at the selected positions to the integral target radiation sound field is analyzed, the positions where the silencers need to be installed and the required silencing amount are obtained according to the contribution, and corresponding silencing equipment is designed.

2. The noise control method according to claim 1,

calculating to obtain the eddy noise sound power of the rest thermal boilers according to the model of the target power plant, obtaining the noise sound power of the gas exhauster according to the delivery value of the gas exhauster, and obtaining the main noise sound source of the waste heat boiler through comparative analysis;

said L_{sourc-etarget}、L_source-refAnd respectively selecting main noise sources.

3. The noise control method according to claim 2,

and analyzing the main noise source of the waste heat boiler according to the model of the reference power plant so as to compare the main noise source with the analysis result of the target power plant and verify the analysis result of the main noise source.

4. The noise control method according to claim 1, wherein a position having a largest contribution amount to the radiated sound field is selected as a position where the muffling apparatus is installed.

5. The noise control method of claim 4, wherein the noise control is performed based on a reference radiated sound intensity measurement value L_refAnd establishing an integral reference radiation sound field of the reference power plant and a plurality of independent reference radiation sound fields at selected positions so as to compare the integral reference radiation sound field with the independent target radiation sound field and verify the distribution condition of the radiation sound fields.

6. The noise control method of claim 5, wherein the selected locations include a waste heat boiler furnace wall, a waste heat boiler and chimney junction, a horizontal flue outer wall, a chimney exhaust, a unit, and a main building.

7. The noise control method of any one of claims 1-5, wherein the target acoustic transmission loss and the reference acoustic transmission loss each comprise an oven cavity acoustic transmission loss, the oven cavity acoustic transmission loss being calculated as follows:

and establishing a local tube array sound intensity model of a single heat exchange tube layer in the waste heat boiler, acquiring corresponding local sound intensity sound transmission loss, and superposing the sound transmission loss of each tube heat exchange tube layer in the waste heat boiler to acquire the sound transmission loss of the furnace chamber.

8. The noise control method according to claim 7, wherein the sound transmission loss superimposed value is corrected in accordance with a change in sectional area of the horizontal flue, the cavity of the exhaust-heat boiler, a section of the exhaust-heat boiler connected to the chimney, and/or a change in temperature in the furnace, to obtain a sound transmission loss in the cavity.

9. The noise control method of any one of claims 1-5, wherein the representative locations are selected from a group of heat exchange tubes, a horizontal flue, a chimney barrel, and a chimney opening in a cavity of the waste heat boiler.

10. The noise control method of any one of claims 1-5, wherein the muffling apparatus is a resistive muffler comprising a plurality of vertically arranged muffling sheets;

the noise reduction sheet is designed as follows: the silencer is distributed at the installation position in a fan shape, and the thickness of the silencing pieces at two sides of the silencer is smaller than that of the rest silencing pieces.