JP5939554B2 - Gas turbine exhaust equipment - Google Patents

Description

  The present invention relates to gas turbine exhaust equipment, which is devised to suppress the generation of noise due to low-frequency sound, and is particularly applicable to a simple cycle plant.

As power plants using gas turbines, there are a combined cycle plant and a simple cycle plant.
In the combined cycle plant, a heat recovery steam generator (HRSG) is provided. The exhaust heat recovery boiler generates steam from the high-temperature exhaust gas discharged from the gas turbine.
On the other hand, the simple cycle plant does not have an exhaust heat recovery facility including an exhaust heat recovery boiler, and exhaust gas exhausted from the gas turbine is released from the exhaust gas flue to the atmosphere through a chimney.

Even if a combined cycle plant is ultimately adopted as a form of power plant using a gas turbine, a simple cycle plant is first constructed and started as a simple cycle plant, and then exhaust heat is recovered. Once the equipment is constructed and the exhaust heat recovery equipment is completed, it is operated as a combined cycle plant.
Moreover, a simple cycle plant may be employ | adopted as the last form of the power plant using a gas turbine.

  In a simple cycle plant, exhaust gas discharged from a gas turbine passes through a flue gas flue arranged in a horizontal direction, and then is exhausted to the atmosphere through a chimney arranged in a vertical direction in communication with the flue gas flue. The At this time, the portion where the end portion of the flue gas flue and the base end portion of the chimney communicate and connect to each other is a bent portion bent at a right angle, and in this bent portion, the exhaust gas flowing at high speed Peeling phenomenon occurs.

When the peeling phenomenon occurs at the bend as described above, the sound velocity is increased due to the high temperature of the exhaust gas, and low frequency sound is generated at the bend, and this low frequency sound is emitted from the smoke outlet. .
Furthermore, the generated low-frequency sound was generated by becoming a standing wave in the exhaust passage composed of exhaust flue and chimney, that is, by resonating and resonating at a frequency defined by the acoustic eigenvalue of the exhaust passage. Low frequency sound was amplified.
When the low-frequency sound (10-30 Hz sound) generated and amplified in this way is emitted from the smoke outlet, low-frequency sound pollution will occur.

  Therefore, various devices have been conventionally used to suppress low-frequency sound generated in a simple cycle plant.

  For example, in the technique shown in Patent Document 1 (Japanese Patent Publication No. 4-13524), a large number of exhaust flues and a part of the chimney are each used as a diffuser, or the exhaust gas flowing in the horizontal direction is commutated into a vertical flow The commutation plate was arranged in the bent part.

In the technique shown in Patent Document 2 (Japanese Patent Application Laid-Open No. 2009-287530), an expansion cylinder (expansion silencer) is concentrically arranged on the outer periphery of the chimney, and the chimney has an internal space of the expansion cylinder (expansion silencer). A communicating opening was formed.

Japanese Examined Patent Publication No. 4-13524 JP 2009-287530 A

  The techniques shown in Patent Documents 1 and 2 are for reducing low frequency sound (sound of 10 to 30 Hz) that has been generated, and for preventing “sound source” itself that generates low frequency sound from occurring. This is not a fundamental measure.

Moreover, the size (diameter direction dimension) of the expansion cylinder (expansion type silencer) used in Patent Document 2 is very large. This is because the size of the expansion cylinder (expanded silencer) is determined by the wavelength of the target frequency.
In other words, the sound generated at the bend is low frequency in the first place, and since the exhaust gas discharged from the gas turbine is hot and the speed of sound is high, the wavelength of the noise sound wave becomes long and the size of the expandable silencer becomes very large. It is.
For example, the diameter and length of the expansion cylinder are about twice the diameter of the chimney.

  In view of the above prior art, the present invention provides a gas turbine exhaust facility having a simple configuration that suppresses noise due to low-frequency sound by suppressing generation of a sound source itself that generates low-frequency sound while ensuring exhaust performance. The purpose is to do.

The present invention for solving the above problems
An exhaust gas flue which is disposed in a horizontal direction through the exhaust gas discharged from the gas turbine, the gas turbine exhaust having a said exhaust gas are arranged vertically in communication with a chimney for discharging to the atmosphere the exhaust gas flue In equipment,
It is installed in an exhaust passage composed of the internal space of the exhaust gas flue and the internal space of the chimney in a state facing the distribution direction of the exhaust gas , and among the exhaust passage, the primary acoustic mode, the acoustic 2 It is characterized by comprising at least one perforated plate that rectifies the flow of the flowing exhaust gas, which is installed in a portion where both the low frequency sound of the next mode and the third acoustic mode are low.

The configuration of the present invention is as follows.
The perforated plate is installed in the internal space of the flue gas flue and the internal space of the chimney ,
The perforated plate installed in the internal space of the flue gas flue has the reference position when the position of the upper surface of the flue gas flue is a reference position in the connection portion where the flue gas flue and the chimney are connected. When are Installation in a region between the 0.75 times away position of the longitudinal dimension of the exhaust gas flue along from the reference position to the exhaust gas flue,
The perforated plate installed in the internal space of the chimney is the reference position when the position of the upper surface of the exhaust gas flue is the reference position of the connection part where the exhaust gas flue and the chimney are connected, It is installed in the area | region between this reference position along the said chimney, and the position 0.75 times away from the vertical dimension of the said chimney .

The configuration of the present invention is as follows.
The aperture ratio of the porous plate is 20 to 70%.

  According to the present invention, since the porous plate is installed in the exhaust passage composed of the internal space of the exhaust gas flue and the internal space of the chimney, it is possible to effectively suppress the generation and resonance of low frequency sound while having a simple configuration. And low frequency noise can be suppressed.

Schematic which shows the power plant provided with the gas turbine exhaust equipment which concerns on the Example of this invention. The characteristic view which shows the relationship between the arrangement position of a perforated panel, and a low frequency sound level. The characteristic view which shows the relationship between the aperture ratio of a perforated panel, and a perforated panel effect.

  Hereinafter, embodiments of the present invention will be described in detail based on examples.

  FIG. 1 is a schematic diagram of a power plant including a gas turbine exhaust facility according to an embodiment. As shown in FIG. 1, the gas turbine 11 constituting the power plant 10 is provided with a compressor 12 and a combustor 13. Air is supplied to the compressor 12, and the compressed air compressed by the compressor 12 is mixed with fuel by the combustor 13 to become fuel gas. The fuel gas is combusted and expanded by the gas turbine 11, and the gas turbine 11 Rotate. Electric power is generated by rotating a generator (not shown) by this rotational force.

The gas turbine exhaust system 20 includes an exhaust gas flue 21 arranged in the horizontal direction and a chimney 22 communicated with and connected to the exhaust gas flue 21 and arranged in the vertical direction. A portion where the end portion of the flue gas flue 21 and the base end portion of the chimney 22 are connected and connected to each other is a bent portion 23 that is bent at a right angle.
In this example, both the flue gas flue 21 and the chimney 22 are configured by rectangular duct pipes having the same vertical and horizontal dimensions in cross section.

  The high-temperature exhaust gas 14 discharged after finishing work in the gas turbine 11 passes through the exhaust gas flue 21 and then is exhausted to the atmosphere through a chimney 22 communicating with the exhaust gas flue 21.

  A porous plate 31 is installed in the internal space of the exhaust gas flue 21 in a state facing the flow direction of the exhaust gas 14, and the internal space of the chimney 22 is porous in a state of facing the flow direction of the exhaust gas 14. A plate 32 is installed. For this reason, all the exhaust gas 14 flows through the holes formed in the porous plate 31 and the holes formed in the porous plate 32.

Thus, since the perforated plates 31 and 32 were installed in the exhaust passage composed of the internal space of the exhaust gas flue 21 and the internal space of the chimney 22 so as to face the flow direction of the exhaust gas 14, The flow is rectified, and the exfoliation phenomenon of the exhaust gas 14 is suppressed at the bent portion 23. As a result, it is possible to suppress the occurrence of low frequency sound accompanying the peeling phenomenon.
Further, since the perforated plates 31 and 32 are installed in the exhaust passage composed of the internal space of the exhaust gas flue 21 and the internal space of the chimney 22, a damping action is exhibited in the sound field of the exhaust passage, and resonance of low frequency sound is achieved. Occurrence of the phenomenon can be suppressed.

  By arranging the perforated plates 31 and 32 in this way, it is possible to suppress the exfoliation phenomenon of the exhaust gas 14 at the bent portion 23 and to suppress the occurrence of the resonance phenomenon of the low frequency sound. Can be prevented.

  Here, the arrangement position and aperture ratio of the perforated plates 31 and 32 that can effectively suppress the generation and resonance of low frequency sound will be described.

First, the arrangement positions of the perforated plates 31 and 32 that can effectively suppress the generation and resonance of low frequency sound will be described.
As shown in FIG. 1, the position of the upper surface of the flue gas flue 21 is a reference position P in the connection portion where the exhaust gas flue 21 and the chimney 22 which are rectangular duct pipes are connected. In addition, let L be the vertical dimension (or the horizontal dimension) of the exhaust gas flue 21 and the chimney 22 which are rectangular duct pipes having the same vertical and horizontal dimensions in the cross section.

In the exhaust gas flue 21, when the region A is defined between the reference position P and a position P1 that is 0.75 L away from the reference position P toward the start end side (gas turbine outlet side) of the exhaust gas flue 21, When the perforated plate 31 is disposed in the region A, the generation and resonance of low frequency sound can be effectively suppressed.
Further, in the chimney 22, when a region B is defined between the reference position P and a position P2 that is 0.75 L away from the reference position P toward the exit side of the chimney 22, the porous plate 32 is disposed in the region B. Then, generation | occurrence | production and resonance of a low frequency sound can be suppressed effectively.

As shown in FIG. 2, in regions A and B, low frequency sound is low in all of the primary acoustic mode, secondary acoustic mode, and tertiary acoustic mode, so porous plates 31 and 32 are arranged in regions A and B. By doing so, the generation and resonance of low frequency sound can be effectively suppressed.
In FIG. 2, the horizontal axis represents the exhaust passage from the gas turbine outlet (start end of the exhaust gas flue) to the chimney tip, and the vertical axis represents the sound pressure level (dB). ing.

Next, the aperture ratio of the perforated plates 31 and 32 that can effectively suppress the generation and resonance of low frequency sound will be described.
The aperture ratio of the porous plates 31 and 32 is preferably 20 to 70%, more preferably 25 to 55%, and most preferably 35 to 45%.

FIG. 3 is an evaluation function that combines pressure loss and low frequency sound level with the aperture ratio of the perforated plates 31 and 32 as a variable. The smaller the value, the more effectively the generation and resonance of the low frequency sound are suppressed. it can. Since the pressure loss tends to decrease to the right with respect to the aperture ratio and the low frequency sound level tends to increase to the right with respect to the aperture ratio, the evaluation function of FIG. 3 was obtained.
In FIG. 3, the horizontal axis represents the aperture ratio (%) of the porous plate, and the vertical axis represents the porous plate effect (an evaluation function value combining pressure loss and low frequency sound level).
As can be seen from FIG. 3, the aperture ratio of the porous plates 31 and 32 is preferably 20 to 70%, more preferably 25 to 55%, and most preferably 35 to 45%.

In the example shown in FIG. 1, the two perforated plates 31 and 32 are arranged, but only one of them may be arranged.
After all, if at least one perforated plate is arranged in the exhaust passage composed of the internal space of the exhaust gas flue 21 and the internal space of the chimney 22, the generation and resonance of low frequency sound can be effectively suppressed.
The number of perforated plates can be one, two, or even three or more.

DESCRIPTION OF SYMBOLS 10 Power generation plant 11 Gas turbine 12 Compressor 13 Combustor 14 Exhaust gas 20 Exhaust equipment of gas turbine 21 Exhaust gas flue 22 Chimney 23 Bending part 31, 32 Perforated plate P Reference position P1, P2 position A, B area

Claims (3)

An exhaust gas flue which is disposed in a horizontal direction through the exhaust gas discharged from the gas turbine, the gas turbine exhaust having a said exhaust gas are arranged vertically in communication with a chimney for discharging to the atmosphere the exhaust gas flue In equipment,
It is installed in an exhaust passage composed of the internal space of the exhaust gas flue and the internal space of the chimney in a state facing the distribution direction of the exhaust gas , and among the exhaust passage, the primary acoustic mode, the acoustic 2 A gas turbine exhaust system comprising at least one perforated plate that rectifies the flow of flowing exhaust gas, which is installed in a portion where both low-frequency sound of the next mode and third-order acoustic mode are low. The perforated plate is installed in the internal space of the flue gas flue and the internal space of the chimney ,
The perforated plate installed in the internal space of the flue gas flue has the reference position when the position of the upper surface of the flue gas flue is a reference position in the connection portion where the flue gas flue and the chimney are connected. When are Installation in a region between the 0.75 times away position of the longitudinal dimension of the exhaust gas flue along from the reference position to the exhaust gas flue,
The perforated plate installed in the internal space of the chimney is the reference position when the position of the upper surface of the exhaust gas flue is the reference position of the connection part where the exhaust gas flue and the chimney are connected, gas turbine exhaust equipment according to claim 1, characterized in that installed in the region between 0.75 times away position of the longitudinal dimension of said chimney along said chimney from the reference position. The opening ratio of the perforated plate, gas turbine exhaust equipment according to claim 1 or claim 2, characterized in that 20 to 70%.

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