JP2001349206A - Denitration control method and device of combined cycle power generation plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a starting schedule of a power generation plant from being influenced by a temperature of an exhaust heat recovering boiler when taking time up to activating a NOx removal catalyst layer in an ordinary starting method when a temperature of the NOx removal catalyst layer lowers as cold start time. SOLUTION: At cold srart time of the power generation plant, high temperature realized compressed air extracted from an air compressor is directly blown upon the NOx removal catalyst layer in the exhaust heat recovering boiler so that this NOx removal catalyst layer is heated, and the NOx removal catalyst layer is quickly activated, and quick-responsiveness is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a denitration control method and apparatus for a combined cycle power plant which suppresses thermal NOx generated in a gas turbine combustor.

[0002]

2. Description of the Related Art A combined cycle power plant is
This is a power generation system that combines a gas turbine plant with a steam turbine plant, sharing the high-temperature area of the thermal energy obtained by fuel combustion with the gas turbine, and sharing the low-temperature area with the exhaust heat recovery boiler and the steam turbine. We are trying to use it effectively.

As shown in FIG. 2, a combined cycle power plant generally includes a gas turbine plant 1, an exhaust heat recovery boiler 2, a steam turbine plant 3, and a generator 4
And the gas turbine plant 1, the steam turbine plant 3, and the generator 4 are directly connected coaxially. The gas turbine plant 1 includes an intake filter chamber 5
The air (atmosphere) sucked from the air is compressed by an air compressor 6 and sent to a combustor 7, where the fuel is burned, and the combustion gas causes the gas turbine body 8 to perform expansion work to obtain a rotational driving force.

[0004] The combustion gas that has finished its work in the gas turbine body 8 becomes exhaust gas EG and is discharged to the atmosphere via an exhaust duct 9, a casing 10 of the heat recovery steam generator 2, a flue 11 and a chimney 12.

Although not shown, a heat exchanger such as a superheater, an evaporator and a economizer is provided in the casing 10 of the exhaust heat recovery boiler (not shown). In addition, an ammonia injection grid 14 and a denitration catalyst layer 15 constituting a denitration control device 13 for removing nitrogen oxides (thermal NOx) in the exhaust gas EG are further installed.

[0006] In addition to the ammonia injection grid 14 and the denitration catalyst layer 15,
An ammonia generator 16 installed outside of 10, an ammonia dilution fan 17 for diluting ammonia with air and supplying it to an ammonia injection grid 14, connecting these ammonia generator 16 and ammonia dilution fan 17 to the ammonia injection grid 14. Pipes 18 and 19, an air shutoff valve 20 provided in the pipe 18, an ammonia gas shutoff valve 21 provided in the pipe 19, an ammonia gas flow control valve 22, and a control device 23 for controlling these valves 20, 21, 22 And so on.

Since the thermal NOx increases as the combustion temperature rises, if the temperature of the gas turbine plant 1 is increased to further increase the efficiency and capacity of the combined cycle power plant, the amount of thermal NOx will further increase. Will be.

[0008] As a technology for suppressing nitrogen oxides currently employed in a combined cycle power plant, NH _{3 is used.}
A denitration catalyst device using (ammonia) is evaluated as the most effective commercial technology. The basic chemical reaction formula for removing nitrogen oxides by this denitration catalyst device is as follows.

4NO + 4NH ₃ + O ₂ → 4N ₂ + 6H ₂ O 6NO + 4NH ₃ → 5N ₂ + 6H ₂ O 6NO ₂ + 8NH ₃ → 7N ₂ + 12H ₂ O

[0010] The efficiency η of the denitration catalyst device is as follows. η = (Nin−Nout) / Nin × 100 (%) (where Nin is the NOx concentration at the catalyst inlet and Nout is the NOx concentration at the catalyst outlet.)

Although the temperature range in which the denitration catalyst can be operated with high efficiency is being developed, a catalyst having high activity at low or high temperature is being developed. However, it is said to be about 200 to 600 ° C. Is determined. At present, the most frequently used catalyst is a medium-temperature catalyst, and the relatively efficient operating temperature range of this catalyst varies depending on the type of active metal.
0-400 ° C.

FIG. 3 is a diagram showing temperature-efficiency characteristics of a general denitration catalyst device. For this reason, the denitration catalyst layer is arranged by selecting an optimal temperature range that satisfies the above temperature conditions.
From ignition of the gas turbine to low load, the nitrogen oxide emission characteristics at the time of unit startup are affected by the temperature characteristics of the exhaust gas at the inlet of the denitration catalyst layer. Startup schedule is affected.

That is, since the denitration catalyst device is designed so as to maximize the nitrogen oxide removal capability at the optimum operating temperature, the daily start-stop operation (DSS; Dairy S
tartand Stop), when the plant is started from a state where both the exhaust heat recovery boiler body and the can water are at high temperature,
The denitration catalyst layer is activated by being exposed to high-temperature exhaust gas, so that relatively high denitration performance can be obtained, and start-up congestion does not easily occur until the exhausted NOx falls below the regulation value.

[0014]

However, when the power plant is shut down for a long period of time, such as during a periodic inspection, the exhaust heat recovery boiler body, the can water and the denitration catalyst layer are all cooled down to the same temperature as the surrounding temperature. I have. When the plant is started from such a cold state (this is called cold start), it takes time to reach a temperature at which the denitration catalyst layer is activated, and during that time, sufficient denitration performance cannot be obtained. By the way, as the startup characteristics of a normal combined cycle plant, it takes about 25 minutes from the ignition of the gas turbine to the joint operation, and the operation time when the environmental characteristics are concerned is also about 40 minutes from the ignition to the low load operation. Take it. Thereafter, the exhaust heat recovery boiler body and the can water are heated by the exhaust heat of the gas turbine.

When the gas turbine main body 8 is started at the time of starting the cooler and the combustor is ignited, the high-temperature exhaust gas EG flows through the exhaust duct 9 through the casing 10 of the exhaust heat recovery boiler. Since the exhaust gas EG flows while heating the exhaust heat recovery boiler main body and the can water, a considerable amount of thermal energy is absorbed before reaching the inlet of the denitration catalyst layer 15.

The exhaust gas EG, which has been deprived of heat energy by the exhaust heat recovery boiler body and the can water, has become low temperature,
The denitration catalyst layer 15 can no longer be sufficiently activated, and is discharged to the atmosphere from the chimney 12 without being able to sufficiently remove nitrogen oxides. Therefore, the power as a power plant cannot be fully exhibited until the exhausted nitrogen oxides fall within the regulation value.

In order to prevent the heat energy of the exhaust gas EG from being absorbed in the flow, the exhaust heat recovery boiler main body and the can water installed upstream of the denitration catalyst layer 15 are separated by steam or another heat source. Although a method of warming is also conceivable, this method has no effect of warming the exhaust heat recovery boiler 2.

For this reason, even if this method is adopted, the heating characteristics of the still water are inferior to the starting characteristics of the gas turbine, so that the mobility as a power generation facility is impaired and the effect is small for investment.

The present invention provides a denitrification control method for a combined cycle power generation system that can operate within a regulated value without impairing mobility even when the power plant is started from a cold state. It is an object to provide a method and an apparatus.

[0020]

In order to solve the above problems, a method for controlling denitration of a combined cycle power plant according to the first aspect of the present invention comprises burning gas turbine fuel together with air compressed by an air compressor. The combustion gas is introduced into a gas turbine, and the combustion gas is introduced into a gas turbine body to perform expansion work to obtain a rotational driving force, and the heat energy of the exhaust gas of the gas turbine is recovered by an exhaust heat recovery boiler. In a combined cycle power plant in which a steam turbine is rotationally driven by output steam of an exhaust heat recovery boiler and an ammonia gas injection unit and a denitration catalyst layer are installed in the exhaust heat recovery boiler along a flow direction of exhaust gas, the denitration catalyst A compressor blower nozzle for injecting compressed air extracted from the air compressor is provided in the vicinity of the bed, and During movement, the temperature of the relationship between the temperature and the denitration catalyst layer of the compressed air is measured, is obtained by such warm the denitration catalyst layer with compressed air injected from the compressor blow-off nozzle on the basis of that relationship.

According to a second aspect of the present invention, a denitration control device for a combined cycle power plant introduces gas turbine fuel into a combustor together with air compressed by an air compressor, and burns the combustion gas. It is introduced into the gas turbine body to perform expansion work to obtain a rotational driving force, and the heat energy of the exhaust gas of the gas turbine is collected by an exhaust heat recovery boiler, and the steam turbine is rotated by the output steam of the exhaust heat recovery boiler. In a combined cycle power plant in which an ammonia injection unit and a denitration catalyst layer are installed in the exhaust heat recovery boiler along a flow direction of exhaust gas in the exhaust heat recovery boiler, a compressor blowout injecting compressed air near the denitration catalyst layer A nozzle is disposed, and a space between the bleed portion of the air compressor and the blower nozzle and bleed air of the air compressor are provided. And it is provided with a bleed blow-off pipe connecting between any portions of the exhaust gas flow path of the gas turbine.

Further, the denitration control device for a combined cycle power plant according to the invention according to claim 3 is characterized in that a denitration catalyst layer side is provided in a bleed air discharge pipe between a bleed portion of the air compressor and a compressor discharge nozzle. The exhaust valve is interposed in a bleed air discharge pipe between the bleed portion of the air compressor and an arbitrary portion of the exhaust gas flow path of the gas turbine.

According to a fourth aspect of the present invention, there is provided a denitrification control device for a combined cycle power plant according to the present invention, wherein the bleed air discharge pipe is bifurcated at an intermediate part and a first end is connected to the air compressor. The second end is connected to an arbitrary portion of the gas turbine exhaust gas flow path via a gas turbine side exhaust valve, and the third end is connected via a denitration catalyst layer side exhaust valve. Connected to the compressor blow-off nozzle.

Further, in the denitration control apparatus for a combined cycle power plant according to the present invention, a denitration catalyst layer temperature detector for detecting a temperature of the denitration catalyst layer is provided near the denitration catalyst layer. When the measured value of the denitration catalyst layer temperature detector is lower than a predetermined value, the denitration catalyst layer side blow-off valve is opened and the bleed air of the air compressor is supplied to the compressor discharge nozzle.

According to a sixth aspect of the present invention, in the combined cycle power plant denitration control device, a denitration catalyst layer temperature detector for detecting a temperature of the denitration catalyst layer is provided near the denitration catalyst layer. An extraction temperature detector for detecting the temperature of the compressed air extracted from the exhaust pipe is provided, and the measured value of the denitration catalyst layer temperature detector is compared with the measurement value of the extraction gas temperature detector. When the measured value of the detector has a predetermined relationship with the measured value of the bleed air temperature detector, the bleed air is supplied to the compressor bleed nozzle by opening the denitrification catalyst layer side blow-off valve.

According to a seventh aspect of the present invention, there is provided a denitration control apparatus for a combined cycle power plant, comprising a denitration catalyst layer temperature detector for detecting a temperature of the denitration catalyst layer near the denitration catalyst layer. An extraction temperature detector for detecting the temperature of the compressed air extracted from the exhaust pipe is provided, and the measured value of the denitration catalyst layer temperature detector is compared with the measurement value of the extraction gas temperature detector. If the measured value of the detector does not have a predetermined relationship with the measured value of the bleed air temperature detector, the exhaust gas flow path side air release valve is opened and the bleed air is discharged to an arbitrary portion of the exhaust gas flow path.

The denitration control apparatus for a combined cycle power plant according to the present invention is provided with a tachometer for measuring the number of revolutions of the gas turbine, and the value of the tachometer is set near the rated number of revolutions. Until that time, one of the exhaust gas flow passage-side exhaust valve and the denitration catalyst layer-side exhaust valve is opened to discharge bleed air from the air compressor to prevent surging.

According to a ninth aspect of the present invention, there is provided a denitration control apparatus for a combined cycle power plant, comprising: a compressor bleeding pipe provided between a bleeding section of the air compressor and a compressor blowing nozzle. A heater is provided so that the denitration catalyst layer can be more quickly activated.

According to a tenth aspect of the present invention, there is provided a denitrification control device for a combined cycle power plant, wherein the compressor bleed heater comprises an auxiliary combustion device for burning fuel by bleeding. The apparatus can be operated and ammonia gas can be supplied to the ammonia injection unit.

[0030]

Embodiments of the present invention will be described below with reference to the accompanying drawings. (First Embodiment) FIG. 1 is a view showing a first embodiment according to the present invention, and is a drawing mainly showing a denitration control device in a combined cycle power plant. Parts corresponding to the prior art are denoted by the same reference numerals.

As shown in FIG. 1, the combined cycle power plant according to the present invention combines a gas turbine plant 1, an exhaust heat recovery boiler 2, a steam turbine plant 3 and a generator 4, and combines the gas turbine plant 1 with the steam turbine plant. 3 and the generator 4 are directly connected coaxially.

The air (atmosphere) sucked from the intake filter chamber 5 is adiabatically compressed by an air compressor 6 and is sent to a combustor 7 as high-temperature and high-pressure compressed air, where the fuel is burned. Then, the combustion gas is introduced into the gas turbine main body 8 to perform expansion work to obtain a rotational driving force.

The combustion gas that has finished its work in the gas turbine body 8 becomes exhaust gas EG, an exhaust duct 9 constituting an exhaust gas flow path, and a casing 1 of the exhaust heat recovery boiler 2.
0, it is discharged to the atmosphere via the chimney 11 and the chimney 12.

In the casing 10 of the exhaust heat recovery boiler, although not shown, a superheater for recovering the heat energy of the exhaust gas along the flow direction of the exhaust gas EG, an evaporator communicating with the drum, and an economizer. A heat exchanger (exhaust heat recovery boiler body) such as a heat exchanger is installed, and further downstream thereof, an ammonia injection grid 14 and a denitration catalyst which are components of a denitration control device 13 for removing nitrogen oxides in the exhaust gas EG. Tier 15
Is installed.

The denitration control device 13 includes the following devices and components in addition to the ammonia injection grid 14 and the denitration catalyst layer 15 described above. That is, an ammonia generator 16 installed outside the casing 10, an ammonia dilution fan 17 for diluting the ammonia sent from the ammonia generator 16 with air and supplying the diluted ammonia to the ammonia injection grid 14, Pipes 18 and 19 for communicating with the injection grid 14, air shutoff valves 20, ammonia gas shutoff valves 21 and ammonia gas flow control valves 22 provided in the middle of the pipes 18 and 19, and these valves 20, 21 And a control device 23 for controlling the control device 22.

The above configuration is the same as that of the prior art shown in FIG. 2, but the present invention has the following components in addition to the above configuration. That is, the air compressor 6 is provided at its middle stage with a bleed portion 6a for bleeding a part of the air which has been adiabatically compressed and has become high temperature, and connects one end 24a of a bleed air discharge pipe 24 to the bleed portion 6a. . This bleed air discharge pipe 24 branches the middle part into two, and one end of one branch pipe (exhaust gas flow path side pipe) 24 b is connected to the exhaust duct 9 via the exhaust gas flow path discharge valve 25. The end of the other branch pipe (pipe on the denitration catalyst layer side) 24c that is open communicates with a compressor discharge nozzle 27 via a denitration catalyst layer side discharge valve 26.

The compressor discharge nozzle 27 is disposed between the ammonia injection grid 14 and the denitration catalyst layer 15,
At the time of starting the cooling of the power plant, the high-temperature and high-pressure compressed air (bleed air) extracted from the air compressor 6 is supplied to the denitration catalyst layer 15.
The denitration catalyst layer 15 functions as a means for accelerating the activation of the denitration catalyst layer 15 by spraying it on the surface.

The bleed air discharge pipe 24 is provided with a bleed air temperature detector 28 for detecting the bleed air temperature, and detects the temperature of the exhaust gas at the inlet of the deNOx catalyst layer near the inlet of the exhaust gas EG of the deNOx catalyst layer 15. A denitration catalyst layer temperature detector 29 is provided. Further, a tachometer 30 for detecting the number of revolutions of the gas turbine is provided.

The control device 23 includes these bleed air temperature detectors 28,
A predetermined calculation is performed by inputting the measurement values from the denitration catalyst layer temperature detector 29 and the rotation speed detector 30.
Control commands to 21, 22, 25, 26, and ammonia generator 16
And a control command to the dilution fan 17 and the like.

When one of the exhaust gas passage-side exhaust valve 25 and the denitration catalyst layer-side exhaust valve 26 provided on the bleed air discharge pipe 24 opens below the rated speed, the gas turbine is started when the gas turbine is started. It also has a function of preventing surging of the air compressor (unstable operation of discharge pressure and flow rate).

Next, the operation of the device of the present invention will be described with reference to FIGS. (1) At the time of starting the cold machine First, the characteristic diagram at the time of starting the cold machine of FIG. 4 will be described. When a start command is issued by a starter (not shown), the gas turbine plant 1 is driven from time t0, and at time t1, the gas turbine plant 1 is rotated up to a purge rotation speed (R2) for purging combustible gas in the gas turbine plant 1 (FIG. 4). T0 to t
1). This purge rotation speed (R2) is held for a certain time (t
1 to t2), and thereafter, the rotational speed is reduced to the ignition speed (R1) (t3).

The air compressor 6 rotates integrally with the gas turbine body 8, adiabatically compresses the air (atmosphere) sucked from the intake filter chamber 5, raises the temperature thereof, and introduces it into the combustor 7. When the combustor 7 is ignited and the combustion gas is supplied to the gas turbine body 8, the gas turbine body 8 is given a driving force by the combustion gas, and drives the air compressor 6, the steam turbine 3, and the generator 4, Rotate up. Here, t4 indicates the time when the exhausted NOx concentration exceeds the regulation value, t5 indicates the time when the gas turbine speed reaches the rated speed (Rs), and t6 indicates the time when the catalyst temperature becomes higher than the extraction temperature.

Next, with reference to the sequence circuit shown in FIG. 5, the exhaust gas passage-side exhaust valve 25 and the denitration catalyst layer-side exhaust valve
Before describing the 26 opening / closing control, three input conditions (A, B, C) will be described.

The input condition A (GT start completion) is satisfied (the logical value becomes "1") when the rotation speed of the gas turbine in FIG. 4 has almost reached the rated rotation speed. B (below the NOx prescribed value) is satisfied (becomes the logical value "1") when it is below the regulated value in FIG.

The input condition C is satisfied (the logical value is "1") when the measured value of the bleed air temperature detector 28 is equal to or greater than the measured value of the denitration catalyst layer temperature detector 29 (this is a predetermined value). When they are in a relationship). In FIG. 5,
NOT1 to NOT8 are NOT circuits, AND1 to AND4
Indicates an AND circuit, and OR1 to OR4 indicate OR circuits.

Hereinafter, the response of FIG. 5 will be described along the time axis of the starting characteristic of FIG. (I) Between time t0 and time t4 (t0 ≦ t <t4) This period is a period of starting the gas turbine, performing a purge operation, igniting the combustor, and increasing the number of revolutions. The input conditions are as follows. is there.

A; "0", B; "1", C; "1". Therefore, the outputs of NOT1 to NOT4 are “1”, and NOT1
5, the output of NOT6 is "0", and the outputs of NOT7, NOT
The output of 8 is "0". As a result, AND1;
"1", AND2 to AND4; "0", so OR
1 and OR4; "1", OR2 and OR3; "0"
Thus, the denitration catalyst layer-side exhaust valve 26 is fully opened, and the exhaust gas passage-side exhaust valve 25 is fully closed. As a result, all the bleed air from the air compressor 6 passes through the denitration catalyst layer side discharge valve 26 and the compressor discharge nozzle
Injected from 27, the denitration catalyst layer 15 is heated.

(Ii) Between time t4 and time t5 (t4 ≦
t <t5) In this period, the NOx concentration exceeds the regulation value, but the rotation speed of the gas turbine has not yet reached the rated rotation speed.

The input condition A remains "0", and NOT
The outputs of 1 to NOT4 remain "1". But N
Since Ox exceeds the regulation value, the input condition B is inverted from "1" to "0", and the outputs of NOT5 and NOT6 are inverted from "0" to "1". Further, since the input condition C remains "1", the outputs of NOT7 and NOT8 remain "0".

As a result, AND1; "0", AND2;
"0", AND3; "1", AND4; "0", and O
R1; “1”, OR4; “1”, OR2; “0”, OR
3: "0", same as the previous period, denitrification catalyst layer side blow-off valve
26 is fully open, and the exhaust gas passage side air release valve 25 continues to be fully closed. Therefore, all bleed air from the air compressor 6 is used for the denitration catalyst layer.
The denitration catalyst layer 15 is further sprayed to further heat the denitration catalyst layer 15.

(Iii) From time t5 to time t6 (t5
≤ t <t6) This period is a period after the rotation speed of the gas turbine reaches the rated rotation speed. During this period, the input condition A; "1", the output of NOT1 to NOT4 is inverted to "0", and the input condition B; "0" remains, the output of NOT5, NOT6 is "1". To continue. Further, since the input condition C remains "1", NOT7,
The output of NOT8 remains "0".

As a result, AND1; "0", AND2;
"0", AND3; "0", AND4; "0",
OR1; “0”, OR2; “0”, OR3; “1”, O
R4; "1", and the denitration catalyst layer-side exhaust valve 26 and the exhaust gas passage-side exhaust valve 25 are fully closed. Accordingly, during this period, no air is extracted from the air compressor 6, and all the compressed air of the air compressor 6 is introduced into the combustor 7.

(Iv) After time t6 (t6 ≦ t) As described above, since the input condition A; “1” has already been established, OR3; “1”, OR4; “1”, and the denitration catalyst layer side Both the blow-off valve 26 and the exhaust gas passage-side blow-off valve 25 maintain the fully closed state. Therefore, no air is extracted from the air compressor 6 even during this period, and all the compressed air from the air compressor 6 is introduced into the combustor 7.

As described above, at the time of cold start, the controller 23 opens the exhaust heat recovery side blow-off valve 26 to release the high-temperature bleed air from when the start command is issued to the gas turbine plant 1 until the start is completed. Is sprayed on the denitration catalyst layer 15, so that the activation of the denitration catalyst layer 15 can be promoted.

The control device 23 starts the operation of the ammonia dilution fan 17 when the gas turbine plant 1 is started.
When the ammonia gas cutoff valve 20 is fully opened and the bleed temperature of the air compressor 6 reaches a predetermined temperature (for example, the temperature at which the denitration catalyst is activated), the ammonia gas flow control valve 22 is brought into a controllable state. Further, when the gas turbine plant 1 stops, the ammonia gas shutoff valve 21 is fully closed, and the ammonia gas flow control valve 22 is brought into a control stop state.

In the start-up process ((i) and (ii)) from the start-up of the gas turbine plant 1 to the rated speed, the bleed air of the air compressor 6 must be exhausted to the exhaust gas flow passage side or the exhaust heat recovery boiler. Is controlled so that
Surging of the air compressor 6 can be prevented.

(2) At the time of warm-up start At the time of warm-up start, description will be made without using a start-up characteristic diagram. (I) The period of less than the rated number of revolutions from the start of startup The warm-up start of the unit means that the temperature of both the exhaust heat recovery boiler body and the can water is high due to residual heat by hot banking and the temperature of the denitration catalyst layer is sufficient for activation Start-up when the temperature is too high. In this case, the nitrogen oxide does not exceed the regulation value. At the time of warming-up, the input condition C is “0” because the temperature of the denitration catalyst layer is generally higher than the extraction temperature.

The response of the blow-off valves 25 and 26 during this period will be briefly described. The input conditions are A; "0", B; "1",
C; "0", the outputs of NOT1 to NOT4 are "1", the outputs of NOT5 and NOT6 are "0", and N
The outputs of OT7 and NOT8 are "1".

Therefore, AND1; "0", AND2;
"1", AND3; "0", AND4; "0", OR2; "1", OR3; "1", OR1;
"0", OR4; becomes "0", and the exhaust gas side exhaust valve
25 is fully open, and the denitration catalyst layer side air release valve 26 is fully closed. Thereby, all the bleed air from the air compressor 6 is exhausted into the exhaust duct 9. Also, all the compressed air that has been bled out in the exhaust duct 9
, The surging of the air compressor 6 can be prevented.

At the start of warm-up, it is conceivable that the bleed air temperature is higher than the temperature of the catalyst layer. Therefore, the response in this case will be described. In this case, the input condition is A;
"0", B; "1", C; "1", AND1
Only "1", so OR1; "0", OR4;
"1" The catalyst device-side exhaust valve 26 is fully opened, and the exhaust gas passage-side exhaust valve 25 is fully closed, and the exhaust gas heats the denitration catalyst layer 15.

When the exhaust gas EG from the gas turbine 8 raises the temperature of the exhaust heat recovery boiler and the can water, that is, when the temperature of the catalyst layer exceeds the bleeding temperature (C; "0"), the exhaust gas The road side exhaust valve 25 is fully opened, and the catalyst side exhaust valve 26 is fully closed.

As described above, when the bleed gas temperature is higher than the temperature of the denitration catalyst layer, the denitration catalyst layer 15 is reliably heated by the exhaust gas. In addition, even when the bleed air temperature is higher or lower than the temperature of the denitration catalyst layer, if the rotation speed of the gas turbine 8 does not reach the vicinity of the rated rotation speed, the air compressor 6
All the bleed air is exhausted to the exhaust gas passage, so that surging of the air compressor 6 can be prevented.

(Ii) Period above the rated speed Since the turbine speed is above the rated speed during this period, the input condition A is inverted from “0” to “1” and NO
The outputs of T1 to NOT4 are inverted from “0” to “1”.
Since the input condition B is not changed by “1”, NOT5, NO
The output of T6 continues to be "0". Since the input condition C remains "0", the outputs of NOT7 and NOT8 remain "1".

As a result, AND1 and AND4; "0", OR1; "0", OR2; "0", OR3;
"1", OR4; "1", the denitration catalyst layer side air release valve 26
In addition, the exhaust gas flow passage-side exhaust valve 25 is fully closed. During this period, since the exhaust heat recovery boiler main body and the can water are considerably warmed by the exhaust gas, the heating by the bleeding is not necessary, so the bleeding from the air compressor 6 is stopped, and the compressed air of the air compressor 6 is stopped. Are all introduced into the combustor 7. Further, when the speed of the air compressor 6 increases to near the rated rotation speed, there is no possibility of surging, so that there is no problem even if the two blow-off valves are closed.

(Second Embodiment) FIG. 6 is a diagram showing a second embodiment according to the present invention. This embodiment is different from the first embodiment in that a heating device 28 is provided on the side of the compressor discharge nozzle 27 of the discharge air discharge pipe 24 to heat the discharge air. The heating device 28 according to the present embodiment is of an auxiliary combustion type in which fuel is added to bleed air and burned. In this case, since nitrogen oxides are generated from the heating device 28, the ammonia generation device 16 and the dilution fan 17 are kept on standby so that the denitration control device 13 is activated as soon as the fuel starts burning.

According to the present embodiment, since the temperature of the bleed air can be further increased, the activation of the denitration catalyst layer 15 can be accelerated. The bleed air discharge pipe 24 is made to branch off from the intermediate part in both FIG. 1 and FIG. 2, but instead of this, the exhaust gas flow path side pipe 24b and the compressor discharge nozzle side pipe 24c may be directly connected to the bleed portion 6a of the air compressor 6, respectively.

Further, the temperature detector is provided only with the denitration catalyst temperature detector 29, and the measured value of this temperature detector is compared with a predetermined value (a temperature sufficient for activating the catalyst). Good.

Further, the exhaust gas passage side pipe 24b may be connected to an appropriate exhaust gas passage connected to the chimney 12 without being connected to the exhaust duct 9. Further, the heating device 28 may be replaced with an electric heater type instead of the auxiliary combustion type. Further, the heating may be performed using steam from another combined power generation plant that is being started.

[0069]

As described above, according to the present invention, when the temperature near the inlet of the denitration catalyst layer is lower than the bleeding temperature of the air compressor, such as at the time of starting a cooler, the bleed air is blown to the denitration catalyst layer to remove denitration. Since the catalyst layer is warmed and the denitration catalyst layer is activated early, a combined cycle power plant that is responsive to a start command can be provided without providing a large-scale facility.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment according to the present invention.

FIG. 2 is a diagram showing a conventional technique.

FIG. 3 is a temperature-efficiency characteristic diagram of a general denitration catalyst device.

FIG. 4 is a diagram showing a unit starting characteristic.

FIG. 5 is a sequence circuit diagram for explaining the operation of the blow-off valve.

FIG. 6 is a diagram showing a second embodiment according to the present invention.

[Description of Signs] 1 ... Gas turbine plant, 2 ... Exhaust heat recovery boiler, 3 ...
Steam turbine plant, 4 ... Generator, 5 ... Intake filter chamber, 6 ... Air compressor, 7 ... Combustor, 8 ... Gas turbine body, 9 ... Exhaust duct, 10 ... Casing, 11 ... Flue, 12 ...
Chimney, 13: denitration control device, 14: ammonia injection grid, 15: denitration catalyst layer, 16: ammonia generation device, 17 ... ammonia dilution fan, 23 ... control device, 24 ... bleed air discharge pipe, 24b ... exhaust gas flow path side Pipe line, 24c: denitration catalyst layer side pipe line, 25: exhaust gas flow path side discharge valve, 26: denitration catalyst layer side discharge valve, 27 ... compressor discharge nozzle, 28 ... bleed temperature detector, 29
... Denitration catalyst layer temperature detector, 30 ... Tachometer.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F01N 3/20 B01D 53/36 101A 3/24 F23J 15/00 A F term (reference) 3G081 BA02 BA11 BB00 BC07 BD00 DA21 3G091 AA06 AB05 BA03 BA04 BA14 CA01 CA02 CA13 CA17 CA21 CB08 DA01 DA02 DB10 EA01 EA15 EA17 EA18 EA26 FA02 FB02 FC07 HA36 HB07 3K070 DA02 DA22 4D048 AA06 AB02 AB03 AC04 CA03 CC39 CC53 DA01 DA02 DA11

Claims (10)

[Claims] 1. A gas turbine fuel is introduced into a combustor together with air compressed by an air compressor and burned, and the combustion gas is introduced into a gas turbine main body to perform expansion work to obtain a rotational driving force. The exhaust gas of the gas turbine is introduced into an exhaust heat recovery boiler, the heat energy of the exhaust gas is recovered by the exhaust heat recovery boiler, and the steam turbine is rotationally driven by the output steam of the exhaust heat recovery boiler. In a combined cycle power plant in which an ammonia gas injection unit and a denitration catalyst layer are installed along a flow direction of exhaust gas, a compressor discharge for injecting compressed air extracted from the air compressor is provided near the denitration catalyst layer. A wind nozzle is provided to measure the relationship between the temperature of the compressed air and the temperature of the denitration catalyst layer when the cold start of the power plant is started, and the pressure is determined based on the relationship. Denitration control method of combine cycle power plant, characterized in that machine blow-off by I噴 compressed air from a nozzle warming the denitration catalyst layer. 2. A gas turbine fuel is introduced into a combustor together with air compressed by an air compressor and burned, and the combustion gas is introduced into a gas turbine main body to perform expansion work to obtain a rotational driving force. The exhaust gas of the gas turbine is introduced into an exhaust heat recovery boiler, the heat energy of the exhaust gas is recovered by the exhaust heat recovery boiler, and the steam turbine is rotationally driven by the output steam of the exhaust heat recovery boiler. In a combined cycle power plant in which an ammonia gas injection unit and a denitration catalyst layer are installed along a flow direction of exhaust gas, a compressor discharge nozzle that injects compressed air near the denitration catalyst layer is arranged, and the air A connection is made between the bleed portion of the compressor and the compressor discharge nozzle, and between the bleed portion of the air compressor and any part of the gas turbine exhaust gas flow path. Denitration control apparatus of the combined cycle power generation plant, characterized in that a bleed blow-off pipe that. 3. The air extraction pipe according to claim 1, further comprising a denitration catalyst layer-side air release valve inserted into a line between the air extraction part of the air compressor and a compressor air discharge nozzle. 3. An exhaust gas flow passage-side exhaust valve is interposed in a conduit between the extraction section and an arbitrary part of a gas turbine exhaust gas flow passage.
3. The denitration control device for a combined cycle power plant according to <1>. 4. The bleed air discharge pipe branches off an intermediate part and connects a first end to a bleed part of the air compressor.
Is connected to an arbitrary portion of a gas turbine exhaust gas flow path via a gas turbine side exhaust valve, and a third end is connected to the compressor exhaust nozzle via a denitration catalyst layer side exhaust valve. The denitration control device for a combined cycle power plant according to claim 2, wherein the denitration control device is connected. 5. A denitration catalyst layer temperature detector for detecting a temperature of the denitration catalyst layer is provided in the vicinity of the denitration catalyst layer, and when a measured value of the denitration catalyst layer temperature detector is lower than a predetermined value, the denitration catalyst is removed. The bleed air of the air compressor is supplied to the compressor discharge nozzle by opening a catalyst layer side discharge valve.
A denitration control apparatus for a combined cycle power plant according to claim 4. 6. A denitration catalyst layer temperature detector for detecting the temperature of the denitration catalyst layer near the denitration catalyst layer, and an extraction temperature detector for detecting the temperature of the compressed air extracted from the air compressor. The measured values of both of these temperature detectors are input, and when the measured value of the bleeding temperature detector is in a predetermined relationship with the measured value of the denitration catalyst layer temperature detector, the denitration catalyst layer side blow-off valve 5. A control device for selecting a control signal and providing an open command thereto.
A denitration control device for a combined cycle power plant according to any one of the above. 7. A denitration catalyst layer temperature detector for detecting a temperature of the denitration catalyst layer near the denitration catalyst layer, and an extraction temperature detector for detecting the temperature of compressed air extracted from the air compressor. If the measured value of the degassing temperature detector is not in a predetermined relationship with the measured value of the glass catalyst layer temperature detector, the exhaust gas flow 5. The denitration control device for a combined cycle power plant according to claim 3, further comprising a control device for selecting a valve and giving an opening command to the valve. 8. A tachometer for measuring the number of revolutions of the gas turbine is provided, and until the measured value of the tachometer becomes close to the rated number of revolutions, the exhaust gas passage side exhaust valve or the denitration catalyst layer side 5. The denitration of a combined cycle power plant according to claim 3, further comprising a control device for selecting one of the blow-off valves and giving an opening command thereto. Control device. 9. A compressor bleed heater is provided in a bleed air discharge pipe between the bleed portion of the air compressor and the compressor blow nozzle. A denitration control device for a combined cycle power plant according to any one of the above. 10. The compressor bleed heater comprises a combustion assist device that burns fuel by bleeding, enables the combustion assist device to operate from the start of the gas turbine, and supplies ammonia gas to the ammonia injection unit. The denitration control device for a combined cycle power plant according to claim 9, wherein: