JPH1181919A - White smoke of exhaust gas preventing method in binary cycle gas turbine device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of white smoke without increasing exhaust amount of nitride oxide by bypassing an exhaust heat recovery part on a downstream side by flowing a part of exhaust gas passed through a denitration part to a bypass route, merging exhaust gas with exhaust gas passed through the exhaust heat recovery part on the downstream side, raising an exhaust gas temperature and discharging exhaust gas to the outside air. SOLUTION: In this binary cycle gas turbine device, a steam injection route 14 from an exhaust heat boiler 2 to a gas turbine 1 is constituted and an exhaust gas route 4 where a denitration part 9 is arranged between an exhaust heat recovery part on the upstream side of an exhaust heat boiler and an exhaust heat recovery part on the downstream part is provided, as a first method. In this case, a bypass route 18 bypassing the exhaust heat recovery part on the downstream side is constituted, exhaust gas is made to bypass the exhaust heat recovery part on the downstream side by flowing a part of exhaust gas passed through the denitration part to the bypass route and exhaust gas is discharged to the outside air by raising an exhaust gas temperature by merging exhaust gas with exhaust gas passed through the exhaust heat recovery part on the downstream side and steam amount to be injected to the gas turbine 1 via the steam injection route 14 is reduced, in the white smoke of exhaust gas preventing method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing white smoke in exhaust gas in a two-fluid cycle gas turbine device.

[0002]

2. Description of the Related Art For example, as one of the gas turbine systems used in cogeneration systems and the like, steam is generated by recovering heat from a gas turbine exhaust gas in an exhaust heat recovery boiler installed in an exhaust path leading to a chimney. A so-called two-fluid cycle gas turbine has been conventionally used in which the output of the gas turbine is increased by returning it to the inlet side of the gas turbine and injecting it into two fluids of combustion gas and steam.

[0003] The amount of water in the exhaust gas of such a two-fluid cycle gas turbine is larger than that of other gas turbines which do not perform the steam because the amount of steam is ejected. For this reason, when discharged from the chimney, the exhaust gas becomes white smoke depending on the outside air condition. White smoke is a phenomenon in which flue gas discharged from a chimney diffuses and mixes with the atmosphere, thereby lowering the temperature, lowering the saturated water vapor pressure, and condensing water that cannot be used as a gas to appear white. For example, in FIG. 3 or FIG. 6 showing the mixed state of the exhaust gas and the atmosphere, when the state of the exhaust gas discharged from the chimney is G1, white smoke is generated in the state of being mixed with the atmosphere because the gas enters the supersaturated region. As described above, white smoke is not subject to environmental regulations because it is caused by water vapor, but may be a visual problem.

[0004] In order to suppress the generation of white smoke, it is necessary to lower the moisture content in the exhaust gas, that is, the specific humidity, or to increase the exhaust gas temperature. For example, in FIG. 6 described above, when the temperature of the exhaust gas is raised and the state of G1 is shifted to the state of G2 so that the straight line connecting the states A and G2 of the atmosphere is tangent to the saturation specific humidity line, Even in a mixed state, it does not enter the supersaturation region. That is, when the state of the atmosphere is A, if the temperature of the exhaust gas is equal to or higher than the temperature of G2, no white smoke is generated.

[0005] Conventional methods for suppressing the generation of white smoke based on such a principle include (1) a method of reheating the exhaust gas using fuel, and (2) a method of boiler bypass of a part of the exhaust gas. Are known. For example, see "Cogeneration" Vol.12 No.1 1997 (pp.15-19).

FIG. 5 shows an example of an exhaust system of a gas turbine to which the method (2) is applied. In this system, an exhaust path 4 from a gas turbine 1 to a chimney 3 via a waste heat boiler 2 is provided. A boiler bypass path 5 that bypasses the waste heat boiler 2 is configured, and the boiler bypass path 5
Is provided with a damper 6. The exhaust heat boiler 2 includes an evaporator 7, a boiler drum 8, a catalyst denitration unit 9 (medium-temperature denitration catalyst), an evaporator 10, and an economizer 11 sequentially from the upstream side. Reference numeral 12 denotes a water supply system of the economizer 11. Water supplied from a water supply tank 13 or the like passes through the economizer 11, is exchanged with exhaust gas, is preheated, and is supplied to the boiler drum 8. Boiler drum 8
A steam injection path 14 is configured on the upstream side of the gas turbine 1, and a flow control valve 15 and a flow meter 16 are installed in the steam injection path 14. The controller 17 constitutes the injection steam amount control means.

In the above system, a part of the exhaust gas of the gas turbine 1 flows through the boiler bypass path 5 and is mixed with the exhaust gas having passed through the exhaust heat boiler 2 and then discharged from the chimney 3. The temperature of the exhaust gas is higher than the temperature of the exhaust gas that has passed through the exhaust heat boiler 2, and therefore, the generation of white smoke can be suppressed.

[0008]

However, as shown in FIG. 5, when the denitration unit 9 is provided in the exhaust heat boiler 2 to reduce nitrogen oxides in the exhaust gas, the exhaust gas is bypassed as described above. Then, since the bypassed exhaust gas does not pass through the denitration unit 9, nitrogen oxides exceeding the regulation value may be discharged from the chimney 3. Therefore, an object of the present invention is to solve such a problem.

[0009]

In order to solve the above-mentioned problems, according to the present invention, first, as a first method, a steam injection path from an exhaust heat boiler to a gas turbine is formed and an upstream of the exhaust heat boiler is provided. In a two-fluid cycle gas turbine device having an exhaust path in which a denitration unit is arranged between the exhaust heat recovery unit on the side and the exhaust heat recovery unit on the downstream side, a bypass path is configured to bypass the exhaust heat recovery unit on the downstream side, Part of the exhaust gas that has passed through the denitration unit flows through the bypass path to bypass the exhaust heat recovery unit on the downstream side, and joins with the exhaust gas that has passed through the exhaust heat recovery unit on the downstream side to raise the exhaust gas temperature and discharge it to the outside air. In addition, a white smoke prevention method for exhaust gas in a two-fluid cycle gas turbine device that reduces the amount of steam injected to a gas turbine via a steam injection path is proposed.

According to the present invention, in the first method, a damper is provided in the bypass path so that the amount of the exhaust gas to be bypassed can be adjusted, and the exhaust gas temperature is set in the exhaust path downstream of the junction of the bypass path. A detector is installed, and the opening degree of the damper is controlled by the control device so that the temperature of the exhaust gas discharged to the outside air detected by the exhaust gas temperature detector becomes a set value, and the amount of the exhaust gas to be bypassed is adjusted. suggest.

According to the present invention, as a second method, a two-fluid cycle gas turbine in which exhaust gas of a gas turbine is recovered in a waste heat boiler to generate steam, and this steam is returned to the inlet side of the gas turbine and injected. In the device,
In the water supply system of the economizer provided in the exhaust path of the gas turbine, a water supply bypass path that bypasses the economizer is configured, and a part of the water supply of the economizer flows through the water supply bypass path to raise the exhaust gas temperature and discharge it to the outside air. In addition, the present invention proposes a method for preventing white smoke from exhaust in a two-fluid cycle gas turbine device that reduces the amount of steam injected into a gas turbine via a steam injection path.

According to the second aspect of the present invention, in the second method, a flow rate control valve is provided in the water supply bypass path, and an exhaust gas temperature detector is provided in an exhaust path downstream of the economizer. It is proposed to control the opening of the flow control valve so that the detected temperature of the exhaust gas discharged to the outside air becomes a set value, and adjust the amount of water supplied to bypass the economizer.

According to the present invention, in the first and second methods, it is proposed that the set value of the temperature of the exhaust gas discharged to the outside air is set as a minimum temperature based on the outside air temperature and the outside air relative humidity. .

Further, in the present invention, in the first and second methods, the injected steam amount control means in the steam injection path includes the first injected steam amount for setting the injected steam amount corresponding to a desired gas turbine output. In addition to the amount setting means, a second injection steam amount setting means for deriving and setting the injection steam amount at the white smoke generation limit from the conditions of the outside air and the exhaust gas at the time of exhaust gas discharge is constituted. Of the setting values of
It is proposed to select the lower value to be the target value of the injected steam amount.

In the present invention, in the above method,
Derivation of the injected steam amount by the second injected steam amount setting means includes a step of obtaining a white smoke generation limit specific humidity from an outside air temperature, an outside air relative humidity, and an exhaust gas temperature, and a step of obtaining an exhaust gas amount from a fuel consumption amount. And the step of obtaining the amount of injected steam at the limit of white smoke generation from the values obtained in these steps. Further, the exhaust gas amount can be determined from the correspondence relationship with the gas consumption amount or the gas turbine intake air amount or the gas turbine output in addition to the relationship between the exhaust gas amount and the fuel consumption amount.

[0016]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram showing a first embodiment of an exhaust system of a gas turbine apparatus to which the present invention is applied. Components similar to those of the conventional exhaust system shown in FIG. Therefore, duplicate description will be omitted. As shown in FIG. 1, in the exhaust system according to the present invention, the exhaust heat recovery section on the downstream side of the exhaust heat boiler 2, that is, in the configuration shown in the drawing, the evaporator 10 and the economizer 11 are bypassed, Path 18 which joins at the position P
, And a damper 19 is provided in the bypass path 18. The damper 19 is configured to control the opening degree by the control device A via the drive mechanism 20. The control device A adjusts the opening degree of the damper 19 so that the temperature of the exhaust gas discharged to the outside air via the chimney 3 becomes a set value. It is configured to be controlled.
For this purpose, an exhaust gas temperature detector 21 is installed in the exhaust path 4 downstream of the junction P of the bypass path 18, and the control device A performs PID control or the like in accordance with a target value set in the exhaust gas temperature setting means configured therein. The opening degree of the damper 19 is controlled by a feedback control method. In addition, the control method of the opening degree of the damper 19 by the control device A is as follows.
It goes without saying that feed-forward control and other well-known appropriate methods can be applied. The specific configuration of the control device A will be described later.

In the above configuration, the exhaust gas from the gas turbine 1 is radiated through the evaporator 7 of the exhaust heat boiler 2 to recover the exhaust heat. After the steam is generated, the denitration with the intermediate temperature denitration catalyst is performed. It is denitrated through the part 9. Next, the exhaust gas passes through the evaporator 10 and the economizer 11 to further collect exhaust heat, and then is discharged from the chimney 3 to the outside air. When the damper 19 is open, a part of the exhaust gas that has been denitrated through the denitration unit 9 bypasses the evaporator 10 and the economizer 11 and flows through the bypass path 12, and the economizer 1
On the downstream side of 1, the exhaust gas is discharged to the outside air after being combined with other exhaust gas. The temperature of the exhaust gas flowing through the bypass route 18 is high because heat is not dissipated in the evaporator 10 and the economizer 11. Therefore, the temperature of the exhaust gas discharged from the chimney 3 increases as the amount of exhaust gas flowing through the bypass route 18 increases.

At this time, the temperature of the exhaust gas discharged from the chimney 3 depends on the exhaust path 4 from the economizer 11 to the chimney 3.
Is measured by the exhaust gas temperature detector 21 at an appropriate place, and the measured value is compared with the set value by the temperature setting means of the control device A to control the opening degree of the damper 19. At this time, the exhaust gas temperature setting means of the control device A calculates and sets the above-mentioned set temperature at any time, for example, every predetermined time, based on the outside air temperature and the outside air relative humidity measured by a suitable detector (not shown). Is performed. Then, the control device A compares the exhaust gas temperature with the set value, and controls the opening degree of the damper 19 via the drive unit 20 so as to maintain the exhaust gas temperature at the set value.

At the same time as the above control, the control device B of the injection steam amount control means obtains the white smoke generation limit specific humidity from the temperature of the exhaust gas set by the control device A and the temperature and the relative humidity of the outside air. Controlling the injection steam amount control means so as to be less than the white smoke generation limit specific humidity to adjust the injection steam amount,
That is, it is reduced.

Next, the control devices A and B of the above embodiment
A specific configuration example will be described. First, the control device A controls the amount of steam generated in the exhaust heat boiler 2 by the bypass path 1.
8 is an example of a configuration accompanied by an operation of setting the degree of opening of the damper 19. That is, the control device A determines the outside air temperature,
The first exhaust gas temperature setting means 24 sets a limit value of the exhaust gas temperature, that is, a lower limit value, based on the outside air relative humidity, and sets the degree of opening of the damper 19 in accordance with the set value.
A second exhaust gas temperature setting means 25 for setting an opening degree of a damper 19 of a bypass passage 18 for controlling a generated steam amount of the exhaust heat boiler 2; and first and second exhaust gas temperature setting means 24, 25. Select the higher one of the setting values for damper 1
9 constitutes the selection setting means 26 for setting the opening degree of the ninth opening. The first exhaust gas temperature setting means 24 determines the opening degree of the damper 19 from the white smoke generation preventing temperature setter 27, the measured value of the exhaust gas temperature detector 21, and the temperature set value of the white smoke generation preventing temperature setter 27. And a controller 28 for setting.

On the other hand, the control device B includes a first injected steam amount setting means 29 similar to the conventional injected steam amount setting means for setting the injected steam amount corresponding to a desired gas turbine output.
And a second injected steam amount setting means 30 for deriving and setting the injected steam amount at the white smoke generation limit from the conditions of the outside air and the exhaust gas when the exhaust gas is discharged from the chimney 4.

FIG. 4 shows the first exhaust gas temperature setting means 2.
4 shows an example of the operation of the white smoke generation prevention temperature setter 27 and the second injected steam amount setting means 30 constituting the fourth embodiment. First, in FIG. 4, in steps S1 and S2, the outside air temperature (t0 [° C.]), the outside air relative humidity (h0 ゜ [%]), and the fuel consumption Fu [m3 / h] are respectively set at appropriate positions. It is measured by the installed measuring instrument. Next, in step S3, step S
A limit value of exhaust gas temperature (t'min [° C.]), that is, a lower limit value is determined from the outside air temperature and the outside air relative humidity measured in 1. For example, as shown in FIG. The outside air relative humidity is stored as a parameter in the form of a function expression or a data table,
The lower limit value of the exhaust gas temperature is obtained by a known method by inputting the fuel consumption measured in 1. The lower limit value of the exhaust gas temperature can be appropriately set by a measurement in advance. In step S4, step S1
From the outside air temperature and outside air relative humidity measured in the above and the exhaust gas temperature obtained in step S3, the white smoke generation limit specific humidity (q [kg
/ kg… wet gas]). In the means constituting step S4, for example, as shown in the drawing, the correspondence between the white smoke generation limit exhaust gas temperature and the specific humidity is stored in the form of a function expression or a data table using the outside air relative humidity as a parameter, By inputting them, a known smoke exhaust gas temperature can be obtained by a well-known method, or can be obtained by directly inputting a function formula as a variable using the current specific humidity, the outside air temperature, and the outside air relative humidity as variables. In step S5, a dry exhaust gas amount (Gd [m3 / h]) is obtained from the fuel consumption measured in step S2. In the means constituting step S5, for example, as shown in the figure, the correspondence between the fuel consumption and the dry exhaust gas temperature is stored in the form of a function expression or a data table,
By inputting the fuel consumption measured in step S2, the dry exhaust gas amount can be obtained by a known method. Next, in step S6, the white smoke generation limit steam flow rate Smax [kg / h] is calculated by the following equation from the white smoke generation limit specific humidity obtained in step S4 and the dry exhaust gas amount obtained in step S5. Smax = q × Gd / (1-q) Then, in step S7, the white smoke generation limit steam flow rate Smax obtained in step S6 is set as the set value of the steam flow rate in the second injected steam amount setting means 30. This set value may be appropriately set lower than the white smoke generation limit steam flow rate Smax obtained in step S6 in consideration of the control range of the steam flow rate. On the other hand, in step S8, step S3
Is set in the first exhaust gas temperature setting means 24. From the above, steps S1, S
Steps S8 and S8 correspond to the operation of the white smoke generation prevention temperature setting device 27 constituting the first exhaust gas temperature setting means 24.
1, S2, S3, S4, S5, S6 and S7 correspond to the operation of the second injected steam amount setting means 30.

As described above, the dry exhaust gas amount can be obtained not only from the above-mentioned correspondence with the fuel consumption but also from the correspondence with the gas turbine intake air amount or the gas turbine output. In step S2, the gas turbine intake air amount or the gas turbine output is measured, and in step S5, the dry exhaust gas amount is determined based on the correspondence between the gas turbine intake air amount or the gas turbine output and the dry exhaust gas amount. Is required.

Next, the selection and setting means 26 compares the set values of the exhaust gas temperatures of the first and second exhaust gas temperature setting means 24 and 25, and selects the higher one of the exhaust gas temperatures, and selects the higher one as described above. Set the opening. In this case, if the set value of the first exhaust gas temperature setting means 24 is lower, the desired amount of emission is obtained at an exhaust gas temperature at which the generation of white smoke can be prevented. When the set value of the means 24 is higher, the amount of generation becomes lower than a desired value, but is suppressed to a necessary minimum. On the other hand, the selection setting means 31 includes first and second injection steam amount setting means 29,
The set values of the injection steam amounts of the respective 30 are compared, and the lower one of the injection steam amounts is selected, and the target value of the opening degree of the flow control valve 15 is set in the controller 17 as described above. In this case, when the set value of the first injected steam amount setting means 29 is lower,
A desired output of the gas turbine 1 is obtained in a state where the generation of white smoke is prevented, and conversely, the second injected steam amount setting means 3
Even when the set value of 0 is lower, the output of the gas turbine 1 is lower than the output corresponding to the set value of the first injected steam amount setting means 29, but is suppressed to the minimum necessary.

With the above control, the temperature of the exhaust gas discharged from the chimney 3 to the outside air rises, and the specific humidity decreases, so that the state of the exhaust gas becomes the state of G3 in FIG. Is prevented. Since the exhaust gas flowing through the bypass path 12 passes through the denitration unit 9, there is no disadvantage to the environmental regulation of nitrogen oxides.

Next, FIG. 2 is a system diagram showing a second embodiment of an exhaust system of a gas turbine apparatus to which the present invention is applied. The conventional exhaust system shown in FIG. 5 and the exhaust system of the present invention shown in FIG. The same components as those in the configuration of the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. As shown in FIG. 2, in the second embodiment, a water supply bypass passage 22 that bypasses the economizer 11 is formed in the water supply system 12 of the economizer 11.
Is provided with a flow control valve 23. The flow control valve 23 is the first
Similarly to the embodiment, the opening degree is controlled by the control device A, and the control device A controls the flow rate control valve 23 so that the temperature of the exhaust gas discharged to the outside air via the chimney 3 becomes a set value. The opening is controlled. In particular,
The control device A has a PID as in the first embodiment.
The opening degree of the flow control valve 23 is controlled by a feedback control method such as control. In addition, the control method of the opening degree of the flow control valve 23 by the control device A can be controlled by applying a feedforward control or other known appropriate methods.

In the above configuration, the exhaust gas from the gas turbine 1 radiates heat through the evaporator 7 of the exhaust heat boiler 2, and after the exhaust heat is recovered, a denitration unit 9 provided with a medium-temperature denitration catalyst is provided.
Is denitrated through Next, the exhaust gas passes through the evaporator 10 and the economizer 11 to further collect exhaust heat, and is then discharged from the chimney 3 to the outside air. The water supplied to the economizer 11 from the water supply tank 13 or the like by the water supply system 12 is preheated by exchanging heat with the exhaust gas in the economizer 11, and then supplied to the boiler drum 8. At this time, when the flow control valve 23 is open, a part of the water supply is bypassed to the water supply bypass passage 22, and the economizer 11
Without being supplied to the boiler drum 8.

At this time, the temperature of the exhaust gas discharged from the chimney 3 to the outside air varies depending on the amount of exhaust heat recovered in the economizer 11, and the amount of water supplied through the water supply bypass passage 22 is small. The higher the amount, the lower the temperature. Conversely, when the amount of water supplied through the water supply bypass passage 22 increases and the amount of water supplied to the economizer 11 decreases, the temperature of the exhaust gas increases.

In the above operation, in the present embodiment,
The temperature of the exhaust gas discharged from the chimney 3 is measured by an exhaust gas temperature detector 21 at an appropriate position on the exhaust path 4 from the economizer 11 to the chimney 3, and the measured value is set to the set value of the exhaust gas temperature setting means of the control device A. The control device A controls the opening degree of the flow control valve 23, and the
The temperature of the exhaust gas discharged to the outside air from the air is maintained at a set temperature according to the outside air condition and the like. The method of setting the exhaust gas temperature at this time is the same as in the first embodiment. Thus, the control device A compares the exhaust gas temperature at that time with the set value, and controls the opening of the flow control valve 23 so as to maintain the exhaust gas temperature at the set value.

At the same time as the above control, the control device B of the injection steam amount control means, based on the temperature of the exhaust gas set by the control device A and the temperature and the relative humidity of the outside air, as in the above-described embodiment. The generation limit specific humidity is determined, and the injection steam amount control means is controlled so that the exhaust gas is equal to or less than the white smoke generation limit specific humidity, thereby adjusting, that is, reducing the injection steam amount.

With the above control, as in the first embodiment, the temperature of the exhaust gas discharged from the chimney 3 to the outside air rises, and the specific humidity decreases.
As a result, the generation of white smoke is prevented.

The specific configuration of the control device A in this embodiment is the same as that of the first embodiment except that the target for setting the opening is different. Further, in the above embodiment, the control device A controls the damper 19 of the bypass path 18 to control the amount of steam generated by the exhaust heat boiler 2.
(Or the flow rate control valve 19 of the water supply bypass passage 18) is configured to have an operation for setting the opening degree. However, when such an operation is not performed, the second exhaust gas temperature setting means 25 and the selection setting are set. The means 26 becomes unnecessary.

[0033]

As described above, the present invention has the following effects. a. The generation of white smoke can be prevented without increasing the emission of nitrogen oxides. b. By using a control method such as feedback,
Thermal efficiency does not decrease to the left.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a first embodiment of an exhaust system of a gas turbine device to which the present invention is applied.

FIG. 2 is a system diagram showing a second embodiment of an exhaust system of a gas turbine device to which the present invention is applied.

FIG. 3 is an explanatory view showing a mechanism of white smoke generation and a mixed state of exhaust gas and the atmosphere showing a white smoke generation preventing action according to the present invention.

FIG. 4 is an explanatory diagram showing an example of a method for obtaining a set value of a white smoke generation prevention temperature.

FIG. 5 is a system diagram showing an exhaust system of a gas turbine using a conventional method for preventing generation of white smoke.

FIG. 6 is an explanatory diagram showing a white smoke generation preventing operation in the exhaust system of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gas turbine 2 Exhaust heat recovery part 3 Chimney 4 Exhaust path 5 Boiler bypass path 6 Damper 7 Evaporator 8 Exhaust heat boiler 9 Denitration part (medium temperature denitration catalyst) 10 Evaporator 11 Economizer 12 Water supply system 13 Water tank 14 Steam injection Path 13 Damper 15 Flow control valve 16 Flow meter 17 Controller 18 Bypass path 19 Damper 20 Drive mechanism 21 Exhaust gas temperature detector 22 Feedwater bypass path 23 Flow control valve 24 First exhaust gas temperature setting means 25 Second exhaust gas temperature setting means 26 selection setting means 27 white smoke generation prevention temperature setter 28 regulator 29 first injected steam amount setting means 30 second injected steam amount setting means

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI F02C 9/16 F02C 9/16 A

Claims (9)

[Claims] An exhaust path comprising a steam injection path from an exhaust heat boiler to a gas turbine and a denitration section disposed between an exhaust heat recovery section on the upstream side of the exhaust heat boiler and an exhaust heat recovery section on the downstream side. In the two-fluid cycle gas turbine device having the above, a bypass path is formed to bypass the exhaust heat recovery section on the downstream side, and a part of the exhaust gas passing through the denitration section is caused to flow to the bypass path to bypass the exhaust heat recovery section on the downstream side. A two-fluid, characterized by raising the temperature of the exhaust gas by merging it with the exhaust gas that has passed through the exhaust heat recovery section on the downstream side to discharge it to the outside air and reducing the amount of steam injected into the gas turbine through the steam injection path Method for Preventing White Smoke from Exhaust Gas in Cycle Gas Turbine System 2. An exhaust gas temperature detector is provided in an exhaust passage downstream of a junction of the bypass passage, wherein a damper is provided in the bypass passage so that the amount of exhaust gas to be bypassed can be adjusted. 2. The two-fluid fluid according to claim 1, wherein the opening degree of the damper is controlled by a control device so that the temperature of the exhaust gas discharged to the outside air detected by the filter becomes a set value, and the amount of the exhaust gas to be bypassed is adjusted. Method for Preventing White Smoke from Exhaust Gas in Cycle Gas Turbine System 3. A two-fluid cycle gas turbine apparatus for recovering heat from an exhaust gas from a gas turbine in an exhaust heat boiler to generate steam and returning the steam to the inlet side of the gas turbine for injection. In the water supply system of the economizer provided, a water supply bypass path that bypasses the economizer is configured, a part of the water supply of the economizer flows through the water supply bypass path to raise the exhaust gas temperature and discharge it to the outside air, and the steam injection path White smoke prevention method for a two-fluid cycle gas turbine device, characterized in that the amount of steam injected into a gas turbine via a gas turbine is reduced. 4. A flow control valve is provided in a water supply bypass path, and an exhaust gas temperature detector is installed in an exhaust path downstream of the economizer, and the temperature of exhaust gas discharged to the outside air detected by the exhaust gas temperature detector is controlled. 4. The white smoke prevention method for a two-fluid cycle gas turbine device according to claim 3, wherein an amount of water supplied to bypass the economizer is adjusted by controlling an opening degree of the flow control valve to a set value. 5. The method according to claim 1, wherein the set value of the temperature of the exhaust gas discharged to the outside air is set as a minimum temperature based on the outside air temperature and the outside air relative humidity. White smoke prevention method in a two-fluid cycle gas turbine device as described above 6. The injection steam amount control means in the steam injection path includes, in addition to first injection steam amount setting means for setting an injection steam amount corresponding to a desired gas turbine output, external steam during exhaust gas discharge. A second injection steam amount setting means for deriving and setting an injection steam amount at a white smoke generation limit from exhaust gas conditions is configured, and a lower one of the set values of these injection steam amount setting means is selected. 5. The method for preventing white smoke from exhaust gas in a two-fluid cycle gas turbine device according to claim 1, wherein the target value of the injected steam amount is set as a target value. 7. The derivation of the injected steam amount by the second injected steam amount setting means includes a step of obtaining a white smoke generation limit specific humidity from an outside air temperature, an outside air relative humidity, and an exhaust gas temperature, and an exhaust gas amount from a fuel consumption amount. The exhaust gas in the two-fluid cycle gas turbine device according to claim 6, wherein the process is performed from a step of obtaining a gas amount and a step of obtaining an injection vapor amount at a white smoke generation limit from each value obtained in these steps. White smoke prevention method 8. The derivation of the injected steam amount in the second injected steam amount setting means includes a step of obtaining a white smoke generation limit specific humidity from an outside air temperature, an outside air relative humidity, and an exhaust gas temperature; 7. The two-fluid cycle gas turbine device according to claim 6, wherein the steps are performed from a step of obtaining an exhaust gas amount from the first step and a step of obtaining an injection steam amount at a white smoke generation limit from each value obtained in these steps. How to prevent white smoke from exhaust 9. The derivation of the injected steam amount in the second injected steam amount setting means includes a step of obtaining a white smoke generation limit specific humidity from an outside air temperature, an outside air relative humidity, and an exhaust gas temperature; The exhaust gas in the two-fluid cycle gas turbine device according to claim 6, wherein the process is performed from a step of obtaining a gas amount and a step of obtaining an injection vapor amount at a white smoke generation limit from each value obtained in these steps. White smoke prevention method