JPH09112215A - Gas turbine power plant and method of operating thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently and efficiently cool a gas turbine without use of an auxiliary boiler even though the pressure, temperature and the flow rate of cooling steam from a waste heat recovering boiler are insufficient so that a steam condition required for cooling the gas turbine cannot be satisied. SOLUTION: A combined cycle power plant 10 or a cogeneration plant incorporating at least a gas turbine 16, a generator 17 and a waste heat recovering boiler 13, includes a steam supply system 30 for feeding steam generated from a waste heat recovering boiler 13, as cooling medium for a high temperature member 33 in the gas turbine 13. A cooling air supply system 40 is connected in the steam supply system 30. In a gas turbine plant 11, cooling steam from the waste heat recovering boiler 13 and cooling air from the cooling air supply system 40 are alternatively used in accordance with an operating condition of the gas turbine 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine plant provided in a combined cycle power generation plant or a cogeneration plant and a method of operating the same, and particularly to a gas turbine plant at the time of turbine trip, load shedding, normal startup, normal shutdown, etc. The present invention relates to a gas turbine plant and a method of operating the gas turbine plant, which can stably maintain the cooling of the gas turbine even during unsteady operation as in the rated operation and perform a safe operation of the gas turbine plant.

[0002]

2. Description of the Related Art At present, a power generation plant using a gas turbine is generally a combined cycle power generation plant because of its high efficiency. A combined cycle power plant is a combination of a gas turbine plant and a steam turbine plant. Exhaust heat from the gas turbine plant is recovered by an exhaust heat recovery boiler, and steam for driving a steam turbine is generated by this exhaust recovery boiler. .

It is known that the improvement of the thermal efficiency of the combined cycle power plant is achieved by increasing the temperature of the gas turbine by increasing the turbine inlet temperature of the gas turbine plant. In the latest gas turbine, the turbine inlet temperature has been raised from 1100 ° C to 1300 ° C
A 300 ° C class gas turbine is about to be applied to an actual power plant.

A conventional gas turbine adopts an air cooling structure using, as a cooling medium, the discharge air of the compressor or the bleed air from an intermediate stage of the compressor as a cooling measure accompanying the high temperature of the gas turbine. The air cooling structure cools high temperature members such as moving and stationary blades of the gas turbine, keeps the metal temperature of these high temperature members low, and secures the mechanical and physical strength of the gas turbine in high temperature combustion gas.

When the turbine inlet temperature of the gas turbine is further increased, the gas turbine efficiency and the combined cycle power generation efficiency are further improved. To improve the power generation efficiency, the cooling efficiency of the turbine moving blades of the gas turbine is further improved. Is an essential condition. Even if the turbine inlet temperature of the gas turbine is increased, a large amount of cooling air is required to maintain the mechanical and physical strength of the gas turbine unless the cooling efficiency of the turbine blades is improved. However, after this cooling air is used for cooling the turbine moving vanes, it is released into the mainstream gas (combustion gas), which lowers the temperature of the mainstream gas, which causes a reduction in power plant efficiency.

When the temperature of the gas turbine is increased, the efficiency of the gas turbine plant, the combined cycle power plant and the cogeneration plant is expected to be improved due to the rise of the turbine inlet temperature. On the other hand, in the air-cooled gas turbine, the turbine moving vanes It is necessary to keep the metal temperature low in order to secure strength, and a large amount of cooling air is required. For this reason, the temperature of the mainstream gas drops, which is a factor that reduces the plant efficiency. When the turbine inlet temperature of the gas turbine is gradually increased from around 1300 ° C., in the air-cooled gas turbine, the influence of the drop in the mainstream gas temperature due to the increase in the cooling air amount becomes stronger,
Even if the turbine inlet temperature is increased, the plant thermal efficiency will not be improved, and the plant thermal efficiency will be reduced.

As a method for suppressing a decrease in plant thermal efficiency, there is a method in which the cooling medium is changed from cooling air to steam or water to increase the heat transfer coefficient on the cooling side. As one of the methods, there is a steam cooling gas turbine in which steam is cooled by flowing steam through a cooling portion of a high temperature member such as turbine moving vanes of a gas turbine. As this steam source, an exhaust heat recovery boiler that recovers the exhaust heat of the gas turbine to generate steam is used, and it is most preferable in terms of plant efficiency and system configuration to use the steam generated by this exhaust heat recovery boiler. .

Further, if the steam after cooling the high temperature member of the gas turbine is joined into the mainstream gas of the gas turbine, the temperature of the mainstream gas is lowered, which is not preferable in terms of plant thermal efficiency. On the other hand, since the steam after cooling still has a high enthalpy, it must be recovered from the gas turbine and flowed into the steam turbine of the combined cycle power plant to be recovered as power or reused as factory process steam. Is also preferable from the viewpoint of improving the thermal efficiency of the entire plant.

However, when the steam generated in the exhaust heat recovery boiler is used for cooling the gas turbine, there are the following problems. That is, the amount of steam generated from the exhaust heat recovery boiler is small and the steam pressure is low during normal startup or normal shutdown when the operating state of the gas turbine changes rapidly, or during turbine trip, load shedding, or low load. Since it is low, the steam conditions required for cooling high temperature members such as turbine moving vanes are not satisfied. For this reason, the metal temperature of the high temperature member of the gas turbine cannot be maintained below the allowable value, and as a result, the gas turbine cannot secure the mechanical and physical strength against the generated thermal stress.

Further, when the generated steam pressure is lower than the pressure of the mainstream gas of the gas turbine, even if there is a slight gap in the joint portion of the gas turbine, the combustion gas of the gas turbine is vaporized by the gas leak from the gap. And circulates in the steam system of the exhaust heat recovery boiler, causing internal corrosion. Furthermore, when the cooling steam itself generated in the exhaust heat recovery boiler is no longer superheated steam suitable for cooling and is drained, it also leads to internal corrosion.

As measures for preventing the corrosion of these steam piping,
There is a method of installing an auxiliary boiler in order to secure necessary steam conditions when starting or stopping the gas turbine or when the load is low. However, the installation of the auxiliary boiler increases the system configuration requirements, makes the system complicated, and reduces the reliability of the power plant. In addition, the operation method of the power plant including the case of a turbine trip becomes complicated, and the burden on the operator increases.

During steady operation or load change operation of the gas turbine, the amount of steam generated can be sufficiently secured in the exhaust heat recovery boiler. Therefore, the amount of cooling steam is adjusted by the cooling steam adjusting valve using the steam from the exhaust heat recovery boiler. Optimal operation is performed by controlling. On the other hand, it is possible to cool the gas turbine even during unsteady operation such as normal start-up where the operating state of the gas turbine changes drastically, normal stop, trip of the gas turbine / steam turbine, load shedding, and turbine equipment. Is required to operate normally and the steam system including the gas turbine / steam turbine and the exhaust heat recovery boiler is safely operated.

In the conventional combined cycle power generation plant 1 shown in FIG. 4, exhaust heat from the gas turbine plant 2 is recovered by an exhaust heat recovery boiler 3 to generate steam for driving a steam turbine 5 of the steam turbine plant 4. .

On the other hand, part of the steam generated in the exhaust heat recovery boiler 3 is supplied as cooling steam to the high temperature member 7a such as turbine moving vanes of the gas turbine 7 through the cooling steam supply system 6, and this cooling steam is supplied. The gas turbine 7 is steam-cooled. The temperature of the steam that has cooled the high temperature member of the gas turbine 7 rises and is recovered by the steam turbine 5 via the steam recovery system 8 to assist the driving of the steam turbine 5.

[0015]

A conventional combined cycle power plant 1 equipped with a steam cooling gas turbine 7 is provided.
At the time of normal start-up in which the operating state changes abruptly, during normal stop, and when the gas turbine 7 or steam turbine 5
During unsteady operation such as when the vehicle trips or when the load is cut off, the steam conditions for the temperature, pressure, and flow rate of the gas turbine cooling steam are insufficient, and the high temperature member 7a of the gas turbine 7 is not sufficiently cooled. There is a problem that excessive thermal stress occurs.

If the temperature, pressure, and flow rate of the gas turbine cooling steam are insufficient, the combustion gas of the gas turbine 7 mixes into the steam system, or the condition of the superheated steam for cooling the gas turbine is insufficient, so that the drainage This causes internal corrosion of the steam supply system 6 and the steam recovery system 8 and the high temperature member 7a and clogging of the drain, and the safety and stability of the gas turbine plant are impaired.

A cogeneration plant also has similar drawbacks or problems.

The present invention has been made in consideration of the above-mentioned circumstances, and when the pressure, temperature and flow rate of the cooling steam from the exhaust heat recovery boiler are insufficient and the steam conditions required for cooling the gas turbine are not satisfied. In addition, a gas turbine plant that is highly reliable and cools the gas turbine sufficiently and efficiently without using an auxiliary boiler and does not generate excessive thermal stress that impairs the safety and stability of turbine equipment. And its driving method.

Another object of the present invention is to minimize mixing of air or steam which may be drained into the steam supply system or the steam recovery system, and to prevent the steam supply system and the steam recovery system from oxidizing or the like. It is an object of the present invention to provide a gas turbine plant and a method for operating the gas turbine plant, which can prevent damage due to internal corrosion in a reliable manner and can operate with high reliability.

Still another object of the present invention is to effectively and effectively prevent supply of steam which may be drained to the hot part cooling part of the gas turbine, and (EN) A gas turbine plant and its operating method capable of reliably and effectively preventing the vapor passage from being blocked due to scale adhesion to deteriorate the cooling efficiency and from causing excessive thermal stress in the gas turbine.

Another object of the present invention is to guide such steam to the turbine outlet side by bypassing the steam turbine when the steam condition for introducing the steam after cooling the high temperature member of the gas turbine into the steam turbine is not satisfied. However, the present invention provides a gas turbine plant and a method of operating the same that prevent damage or breakage of the steam turbine in advance and improve reliability.

[0022]

In order to solve the above-mentioned problems, in a gas turbine plant according to a first aspect of the present invention, there is provided a combined cycle power plant or a co-cycle power plant having at least a gas turbine, a generator and an exhaust heat recovery boiler. In a gas turbine plant that constitutes a generation plant, a steam supply system that can supply the steam generated in the exhaust heat recovery boiler as a cooling medium for a high temperature member of the gas turbine is provided, and a cooling air supply system is provided in the middle of the steam supply system. Are connected, and cooling steam and cooling air as a cooling medium for the high temperature member of the gas turbine can be switched and used according to the operating state of the gas turbine.

In the method for operating a gas turbine plant according to claim 2, in order to solve the above-mentioned problems,
A combined cycle power plant or cogeneration plant includes at least a gas turbine, a generator and an exhaust heat recovery boiler, and steam generated in the exhaust heat recovery boiler and cooling air from a cooling air supply system are cooled by a high temperature member of the gas turbine. In this method, the medium is selectively switched and used, and the cooling medium for the high temperature member of the gas turbine is sequentially switched from cooling air to cooling steam or from cooling steam to cooling air according to the operating state of the gas turbine.

In a gas turbine plant according to a third aspect of the present invention, in order to solve the above-mentioned problems, a gas constituting a combined cycle power plant or a cogeneration plant including at least a gas turbine, a generator and an exhaust heat recovery boiler. In a turbine plant, while providing a steam supply system capable of supplying steam generated in the exhaust heat recovery boiler as a cooling medium for a high temperature member of the gas turbine, a steam recovery system for recovering steam after cooling the high temperature member of the gas turbine And a cooling medium discharge system capable of discharging the collected cooling medium to the atmosphere is provided in the middle of this vapor recovery system.

In the method for operating a gas turbine plant according to claim 4, in order to solve the above-mentioned problems,
The combined cycle power plant or cogeneration plant includes at least a gas turbine, a generator, and an exhaust heat recovery boiler, and enables the steam generated in the exhaust heat recovery boiler to be used as a cooling medium for the high temperature member of the gas turbine, and the high temperature of the gas turbine When the cooling medium of the member is a mixture of cooling air and steam or cooling air, the cooling medium after cooling the high temperature member is released into the atmosphere.

In a gas turbine plant according to a fifth aspect, in order to solve the above-mentioned problems, a gas constituting a combined cycle power generation plant or a cogeneration plant including at least a gas turbine, a generator and an exhaust heat recovery boiler. In a turbine plant, the steam generated in the exhaust heat recovery boiler is provided with a steam supply system capable of supplying as a high temperature member cooling medium of the gas turbine, while a steam recovery system for recovering the steam after cooling the high temperature member of the gas turbine is provided. Provided, connecting the steam bypass system branched from the middle of the steam supply system to the steam recovery system, the cooling steam to the steam supply system and the steam recovery system even when the steam is not used as the high temperature member cooling medium of the gas turbine. It has been distributed.

In the method for operating a gas turbine plant according to claim 6, in order to solve the above-mentioned problems,
The combined cycle power plant or cogeneration plant includes at least a gas turbine, a generator and an exhaust heat recovery boiler, and steam generated in the exhaust heat recovery boiler is steamed even when steam is not used as a cooling medium for the high temperature member of the gas turbine. In this method, the gas turbine is circulated by bypassing the gas turbine from the supply system to the steam recovery system.

In the gas turbine plant according to claim 7, in order to solve the above-mentioned problems, a gas constituting a combined cycle power plant or a cogeneration plant at least equipped with a gas turbine, a generator and an exhaust heat recovery boiler. In a turbine plant, a steam turbine plant equipped with a steam turbine driven by steam generated in the exhaust heat recovery boiler is provided side by side, and steam generated in the exhaust heat recovery boiler can be supplied as a high temperature member cooling medium of a gas turbine. While providing a steam supply system, a steam recovery system that can recover the steam after cooling the high-temperature members of the gas turbine to the steam turbine is provided. This steam recovery system branches the turbine bypass recovery system from the middle and recovers this turbine bypass recovery system. The system bypasses the steam turbine and Is connected to the down outlet, the recovery destination of the recovered cooling medium is obtained switchably to select a steam turbine and condenser.

In the method of operating a gas turbine plant according to claim 8, in order to solve the above-mentioned problems,
The combined cycle power plant or cogeneration plant comprises at least a gas turbine, an exhaust heat recovery boiler, a steam turbine and a generator, and steam generated in the exhaust heat recovery boiler can be used as a cooling medium for a high temperature member of the gas turbine, and a gas. When the steam after cooling the high temperature member of the turbine is recovered in the steam recovery system, the steam after cooling the gas turbine is recovered to the steam turbine outlet side by bypassing the steam turbine depending on the operating state of the gas turbine.

[0030]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example of a combined cycle power generation plant equipped with a gas turbine plant according to the present invention. The combined cycle power generation plant 10 is a multi-shaft type and is a combination of a gas turbine plant 11 and a steam turbine plant 12. Exhaust heat from the gas turbine plant 11 is recovered by the exhaust heat recovery boiler 13, and the exhaust heat recovery boiler 13 generates drive steam for the steam turbine plant 12. The combined cycle power generation plant 10 may be a single shaft type in which the turbine shafts of the gas turbine plant 11 and the steam turbine plant 12 are made common.

In the gas turbine plant 11, a compressor 14 that compresses air, a gas turbine combustor 15 that combusts the discharge air that is compressed by the compressor 14 and has a pressure increased, and a combustor 15 that combusts the gas are combusted. It has a gas turbine 16 that is operated by high-temperature and high-pressure combustion gas, and a generator 17 that is driven by this gas turbine 16.
The fuel is supplied from the fuel supply system 18 through the fuel regulating valve 19. The generator 17 is connected to the turbine shaft 16a of the gas turbine 16 via a coupling (not shown), and the generator 17 is rotationally driven by driving the gas turbine 16 so that the output is taken out.

On the other hand, the combustion gas expanded by working in the gas turbine 16 is subsequently guided to the exhaust heat recovery boiler 13 as exhaust gas, and the exhaust heat recovery boiler 13 recovers the exhaust heat of the exhaust gas. The steam turbine plant 12 is driven to generate steam. In this sense, the exhaust heat recovery boiler 13 functions as a steam generator. The exhaust gas whose exhaust heat is recovered by the exhaust heat recovery boiler 13 passes through the exhaust line and is discharged from the chimney 20 into the atmosphere.

The steam (superheated steam) generated in the exhaust heat recovery boiler 13 is sent to the steam turbine 23 via the main steam system 22, and drives the steam turbine 23 to perform work. The generator 24 is driven by driving the steam turbine 23.
Are driven to rotate, and the output is taken out from this generator 24.

The steam that has worked in the steam turbine 23 and expanded is then sent to the condenser 25, where it is condensed to be condensed water. The condensate is returned to the exhaust heat recovery boiler 13 by the water supply pump 27 via the condensate water supply system 26 and is used for reheating.

In this way, the steam turbine plant 1
2 comprises an exhaust heat recovery boiler 13, a main steam system 22, a steam turbine 23, a condenser 25, a condensate water supply system 26, and a generator 24.

On the other hand, a part of the superheated steam generated in the exhaust heat recovery boiler 13 is guided to the steam supply system 30 for cooling the high temperature member of the gas turbine 16. The steam supply system 30 is taken out from the overheat side of the exhaust heat recovery boiler 13 and is connected to a high temperature member 33 of the gas turbine 16 via a steam cutoff valve 31 and a steam adjusting valve 32 on the way, and is a high temperature member 33 of a turbine moving vane. For example, the turbine steam cooling blade on the high pressure stage side is steam cooled.

Therefore, this gas turbine 16 functions as a steam cooling gas turbine that is cooled by a part of the steam generated from the exhaust heat recovery boiler 13, and a part of the generated steam is cooled by the high temperature member cooling medium (cooling) of the gas turbine 16. Used as steam). The steam that has cooled the high temperature member 33 of the gas turbine 16 is guided to the steam recovery system 34. This vapor recovery system 34 is provided with upstream and downstream vapor cutoff valves 35, 3 on the way.
6 is connected to the low pressure stage of the steam turbine 23.

Thus, the high temperature member 3 of the gas turbine 16
The steam that has cooled 3 is heated by heat exchange with the combustion gas, and after the temperature has risen, is guided to the low pressure stage of the steam turbine 23 through the steam recovery system 34 and is recovered as power. There is.

On the other hand, a cooling air supply system 40 is connected in the middle of the steam supply system 30. The cooling air supply system 40 is taken out from the discharge side of the compressor 14, and is provided with a high temperature member of the gas turbine 16 downstream of the steam adjusting valve 32 of the steam supplying system 30 via an air cutoff valve 41 and an air adjusting valve 42. Connected near 33.

The cooling air supply system 40 uses a compressor when the steam generated from the exhaust heat recovery boiler 13 is not sufficient and the temperature of the combustion gas from the gas turbine combustor 15 is relatively low as compared with the rated operation. The discharge air of 14 is used as a cooling medium (cooling air) of the high temperature member 33 of the gas turbine 16. In order to switch and use the cooling medium of the high temperature member 33 of the gas turbine 16 from air to steam or from steam to air, the cooling air supply system 40 is provided with the air shutoff valve 4
1 and an air regulating valve 42 are provided.

For the same purpose, the steam supply system 30 is also provided with a steam shutoff valve 31 and a steam regulating valve 32. In the steam supply system 30, a temperature detector 43 for detecting whether or not the steam generated in the exhaust heat recovery boiler 13 satisfies the steam condition necessary for cooling the high temperature member 33 such as the steam cooling blades of the gas turbine 16. And a pressure detector 44 is provided. The detection signals from the temperature detector 43 and the pressure detector 44 are discriminated by a discriminator such as a CPU (not shown), and the vapor shutoff valve 31 and the vapor regulating valve 3 are discriminated by an operation controller (not shown) or the like.
2 and the air cutoff valve 41 and the air control valve 42 are switched.

When cooling the high temperature member 33 of the gas turbine 16 with cooling air, or when switching the cooling medium from cooling air to steam or from steam to cooling air, the steam supply / recovery systems 30 and 34 are protected. Therefore, the cooling medium discharge system 45 is provided. The cooling medium discharge system 45 is branched from the middle of the steam recovery system 34, for example, from a portion as close to the cooling unit of the high temperature member 33 of the gas turbine 16 as possible, and is connected to the exhaust side of the exhaust heat recovery boiler 13. The cooling medium discharge system 45 may be opened directly to the atmosphere. A steam blow valve 46 is provided in the middle of the cooling medium discharge system 45.

Thus, the high temperature member 3 of the gas turbine 16
3 is cooled by cooling air, or when the cooling medium is switched from cooling air to steam or steam to cooling air, the high temperature member 33 of the gas turbine 16 is used.
The cooled cooling air or a mixture of cooling air and steam is guided to the cooling medium discharge system 45 and discharged from the chimney 20 into the atmosphere. In this case, the cooling air is the steam recovery system 3
Upstream steam shutoff valve 3
5 is installed in the steam recovery system.

While the high temperature member 33 of the gas turbine 17 is being cooled by the air discharged from the compressor 14, the steam supply system 30 and the steam recovery system 34 from the exhaust heat recovery boiler 13 are preheated (warming up). Therefore, a steam bypass system 48 is provided. The bypass system 48 connects the steam supply system 30 and the steam recovery system 34 and bypasses the gas turbine 17.

The steam bypass system 48 connects the steam supply system 30 and the steam recovery system 34 on the side of the gas turbine 16 as much as possible, and a steam bypass valve 49 is provided on the way. The steam bypass system 48 is branched and taken out from the upstream side of the steam shutoff valve 31 of the steam supply system 30, and is connected between the upstream and downstream steam shutoff valves 35 and 36 of the steam recovery system 34.

The steam bypass system 48 is the steam supply system 3
0 and the steam recovery system 34 are preheated, and at the time of turbine trip or load shedding of the gas turbine 16 or the steam turbine 23, the steam is recovered without guiding the cooling steam to the high temperature member 33 of the gas turbine 16. Therefore, the cooling steam from the exhaust heat recovery boiler 13 is recovered by bypassing the gas turbine 16.

Further, in the steam supply system 30, drain pipes 50 and 51 are branched from the upstream side of the steam shutoff valve 31 and the downstream side of the steam regulating valve 32, respectively. The drain pipes 50 and 51 are provided with drain valves 52 and 53, respectively, and collect the drain of the steam generated in the steam supply system 30 and discharge it to the outside. This is to prevent drain from flowing into the high temperature member 33 of the gas turbine 16 and causing internal corrosion.

Further, a turbine bypass recovery system 55 for bypassing the steam turbine 23 is branched from the middle of the steam recovery system 34. This turbine bypass recovery system 55 is branched from between both steam cutoff valves 35 and 36 of the steam recovery system 34, and is provided with a steam turbine bypass valve 56 as a steam cutoff valve on the way and is connected to the outlet side of the steam turbine 23. . The turbine bypass recovery system 55 may be connected to the condenser 25.

When the steam turbine 23 trips, the turbine bypass recovery system 55 bypasses the steam turbine 23 and recovers the cooling steam recovered by the steam recovery system 34 into the condenser 25.

Next, the operation of the combined cycle power plant 10 will be described.

[Normal Startup] When the combined cycle power plant 10 is started, the gas turbine plant 11 is started according to the following procedure.

(1) During normal drive operation, as shown in FIG. 2, the gas turbine 16 of the gas turbine plant 11 is
Before starting, the steam shutoff valve 31, the steam regulating valve 32 of the steam supply system 30, and the upstream steam shutoff valve 3 of the steam recovery system 34.
5, the air shutoff valve 4 of the cooling air supply system 40
1. Fully open the steam blow valve 46 of the air regulating valve 42 and the cooling medium discharge system 45. In addition, the steam bypass system 48
Steam bypass valve 49 and turbine bypass recovery system 55
The steam shutoff valve 56 is opened and the downstream steam shutoff valve 36 of the steam recovery system 34 is closed.

(2) After setting the open / closed state of each valve as shown in FIG. 2, the gas turbine 16 of the gas turbine plant 11 is started. At the time of starting the gas turbine 16, the high temperature member 33 of the gas turbine 16 is maintained in a turbine inlet temperature range where air cooling is possible, and in this state, it is sufficient to cool the high temperature member 33 of the gas turbine 16 from the exhaust heat recovery boiler 13. Raise it to a state where superheated steam under steam conditions can be obtained. The state of cooling steam from the exhaust heat recovery boiler 13 is constantly detected by the temperature detector 43 and the pressure detector 44.

(3) The drain valve 52 of the drain pipe 50 is opened and closed until the cooling steam of sufficient steam condition is obtained from the exhaust heat recovery boiler 13 to discharge the drain in the steam supply system 30 to the outside. . In addition, the steam turbine bypass valve (steam cutoff valve) 5 of the turbine bypass recovery system 55
6 is closed, the downstream steam shutoff valve 36 of the steam recovery system 34 is opened, and the steam supply system 30 and the steam recovery system 34, which are cooling steam systems, are warmed up.

(4) High temperature member 33 of the gas turbine 16
Exhaust heat recovery boiler 1
At the stage obtained from step 3, the steam shutoff valve 31 of the steam supply system 30 is opened, and the valve opening of the steam adjusting valve 32 is controlled. At the same time, the air regulating valve 4 of the cooling air supply system 40
The valve opening of 2 is also controlled.

At this time, the valve openings of the air adjusting valve 42 of the cooling air supply system 40 and the steam adjusting valve 32 of the steam supply system 30 change from 100% cooling air to a cooling air / steam mixed state and then to the cooling steam 100. The air control valve 42 is controlled to close and the steam control valve 32 is controlled to open.

(5) High temperature member 33 of the gas turbine 16
After confirming that the cooling medium supplied to the system is 100% cooling steam, the upstream side steam shutoff valve 35 of the steam recovery system 34 is fully opened, and the air shutoff valve 41 of the cooling air supply system 40 is opened.
And the steam blow valve 46 of the cooling medium discharge system 45 is fully closed. At this time, the steam bypass valve 49 of the steam bypass system 48 is also closed, and the high temperature member 33 of the gas turbine 16 is cooled by the steam cooling system.

(6) With the gas turbine 16 being cooled by steam cooling, the gas turbine 16 enters the normal operating state from the starting operating state, and enters the rated operation by increasing the load.

[Rated Operation] During the rated operation of the combined cycle power plant 10, the air compressed by the compressor 14 is mixed with fuel in the gas turbine combustor 15 and burned, and the combustion gas is guided to the gas turbine 16. Then, the gas turbine 16 is driven. This gas turbine 1
The drive of 6 drives the generator 17 to rotate, generating electric power.

The combustion gas that drives the gas turbine 16 of the gas turbine plant 12 expands and the heat recovery steam generator 13 expands.
Will be guided to.

Exhaust heat of the combustion gas is recovered by the exhaust heat recovery boiler 13, and heats the feed water supplied from the condensate water supply system 26 of the steam turbine plant 12. The exhaust gas whose temperature has dropped due to the heating of the feed water is guided from the exhaust side of the exhaust heat recovery boiler 13 to the chimney 20, and is discharged from the chimney 20 into the atmosphere.

On the other hand, the steam (superheated steam) generated in the exhaust heat recovery boiler 13 passes through the main steam system 22 and the steam turbine 2
3 to drive the steam turbine 23,
Power is generated at 4.

The steam expanded by working in the steam turbine 23 is subsequently guided to the condenser 25 where it is cooled,
It will be condensed. This condensate is returned to the exhaust heat recovery boiler 13 via the condensate water supply system 26 and is used for reheating.

Further, a part of the superheated steam generated in the exhaust heat recovery boiler 13 is supplied to the high temperature member 33 of the gas turbine 16 through the steam supply system 30 and used for steam cooling.
The steam that has cooled the high temperature member 33 of the gas turbine 16 is guided to the low pressure stage side of the steam turbine 23 via the steam recovery system 34 and is recovered as power.

[Normal Stop] When the combined cycle power plant 10 is normally stopped, the operation of the gas turbine plant 11 is stopped according to the following procedure.

(1) The load of the gas turbine 16 of the gas turbine plant 11 is set to the high temperature member 3 of the gas turbine 16.
3 is reduced to a turbine inlet temperature range where air cooling is possible, and the superheated steam of a steam condition sufficient for cooling the high temperature member 33 of the gas turbine 16 is maintained from the exhaust heat recovery boiler 13 while maintaining this turbine inlet temperature range. Lower and maintain until you obtain it. At this time, the state of the cooling steam from the exhaust heat recovery boiler 13 is detected and monitored by the temperature detector 43 and the pressure detector 44.

(2) Subsequently, the steam blow valve 46 of the cooling medium discharge system 45 is opened, the upstream side steam shutoff valve 35 of the steam recovery system 34 is closed, and the air shutoff valve 41 of the cooling air supply system 40 is turned on. open.

After that, the steam regulating valve 3 of the steam supply system 30
2 and the valve opening degree of the air adjusting valve 42 of the cooling air supply system 40 are adjusted. The valve openings of the steam adjusting valve 32 and the air adjusting valve 42 are changed from 100% of cooling steam to 100% of cooling air through a mixed state of cooling air / steam in order and switched. Adjustment is performed in the direction in which 32 is closed and the direction in which the air control valve 42 is opened. When adjusting the steam adjusting valve 32 in the closing direction, the steam bypass valve 49 of the steam bypass system 48 is opened to allow the surplus steam to flow to the steam recovery system 34 side.

(3) High temperature member 33 of the gas turbine 16
After confirming that the cooling medium is 100% cooled air, the steam shutoff valve 31 of the steam supply system 30 is fully closed.

On the other hand, the drain valve 5 of the drain piping 50, 51
2, 53 are opened and closed to discharge the drain generated in the steam supply system 30 to the outside.

(4) In this state, the gas turbine 16 of the gas turbine plant 11 is stopped.

(5) After the gas turbine 16 is stopped, the steam cutoff valve (steam turbine bypass valve) 56 of the turbine bypass recovery system 55 is opened, and the steam cutoff valve 36 of the steam recovery system 34 is closed, whereby the gas turbine plant 1
The normal stop operation No. 1 ends.

[At the time of trip of gas turbine] When the gas turbine 16 of the gas turbine plant 11 trips, the cooling steam for cooling the high temperature member 33 of the gas turbine 16 from the exhaust heat recovery boiler 13 is processed as follows. To be done.

(1) The fuel control valve 19 supplied to the gas turbine combustor 15 is closed by the trip signal of the gas turbine 16 of the gas turbine plant 11, and the supply of fuel is stopped.

(2) Steam shutoff valve 3 of steam supply system 30
1 is fully closed, and the steam blow valve 46 of the cooling medium discharge system 45
And the air shutoff valve 41 of the cooling air supply system 40 is fully opened.

At this time, the valve openings of the steam adjusting valve 32 and the air adjusting valve 42 of the cooling air supplying system 40 are adjusted so that the reverse flow of the cooling air does not occur in the steam supplying system 30.

(3) Subsequently, the steam bypass valve 49 of the steam bypass system 48 is opened, and after opening this steam bypass valve 49, the steam cutoff valve 36 of the downstream side of the steam recovery system 34 is opened.
Is fully closed and the steam cutoff valve 56 of the turbine bypass recovery system 55 is fully opened. As a result, the superheated steam from the exhaust heat recovery boiler 13 guided through the steam supply system 30 can be guided from the steam bypass system 48 through the turbine bypass recovery system 55 to the condenser 25 and recovered.

Further, in this case, the steam supply system 30
The steam adjusting valve 32 of No. 2 is throttled and the air adjusting valve 42 of the cooling air supply system 40 is gradually opened to make the cooling medium of the high temperature member 33 of the gas turbine 16 100% cooling air. At this time, the mixture of cooling air and steam that has cooled the high temperature member 33 of the gas turbine 16 or cooling air is discharged into the atmosphere via the cooling medium discharge system 45.

[At the time of trip of steam turbine] When the steam turbine 23 of the steam turbine plant 12 trips during the rated operation of the combined cycle power plant 10, the high temperature member 33 of the gas turbine 16 is cooled from the exhaust heat recovery boiler 13. The cooling steam is processed as follows.

(1) In response to the trip signal from the steam turbine 23, the steam cooling gas turbine 16 becomes
Reduce the turbine load so that 6 air cooling is possible,
The turbine inlet temperature of the combustion gas of the gas turbine 16 is lowered.

(2) Subsequently, the upstream steam cutoff valve 35 of the steam recovery system 34 is fully closed, and the steam blowoff valve 46 of the cooling medium discharge system 45 and the air cutoff valve 41 of the cooling air supply system 40.
Fully open. At this time, the valve openings of the steam adjusting valve 32 and the air adjusting valve 42 of the cooling air supplying system 40 are adjusted so that the cooling air does not flow backward in the steam supplying system 30.

(3) Next, the steam bypass valve 49 of the steam bypass system 48 is opened, and after opening this bypass valve 49, the downstream side steam shutoff valve 36 of the steam recovery system 34 is fully closed, and the turbine bypass recovery system is closed. The steam shutoff valve 56 of 55 is fully opened, and a part or all of the surplus cooling steam is guided from the steam bypass system 48 to the turbine bypass recovery system 55 and is recovered in the condenser 25.

Subsequently, the steam regulating valve 3 of the steam supply system 30
2 is narrowed down, the air adjusting valve 42 of the cooling air supply system 40 is gradually opened to gradually change the cooling medium of the high temperature member 33 of the gas turbine 16 to 100% cooling air. At that time, the mixture of steam and cooling air after cooling the gas turbine or the cooling air is discharged from the steam blow valve 46 into the atmosphere through the cooling medium discharge system 45, and the processing at the time of trip of the steam turbine is completed.

[When the load is cut off] In the operation of the combined cycle power generation plant 10, for example, when the load is cut off in the gas turbine plant 11, the steam cooling gas turbine 16 is cooled in the following manner.

(1) When the load of the gas turbine plant 11 is cut off, the valve opening of the fuel adjusting valve 19 is narrowed and the fuel supplied to the gas turbine combustor 15 is reduced. The combustion gas temperature decreases as the fuel decreases.

When the combustion gas temperature falls to a turbine inlet temperature range in which the high temperature member 33 of the gas turbine 16 can be air-cooled, while maintaining the turbine inlet temperature range,
The superheated steam from the exhaust heat recovery boiler 13 is transferred to the gas turbine 16
It is confirmed by detecting with the temperature detector 43 and the pressure detector 44 that the steam condition sufficient for the cooling of No. 2 is provided.

(2) Next, the steam blow valve 46 of the cooling medium discharge system 45 is opened, the upstream steam cutoff valve 35 of the steam recovery system 34 is closed, and the air cutoff valve 41 of the cooling air supply system 40 is opened. .

Next, the steam regulating valve 3 of the steam supply system 30.
2 and the valve opening of the air adjustment valve 42 of the cooling air supply system 40 are adjusted so that the cooling air
The direction in which the air adjusting valve 42 is opened so that the state of 100% cooling air is passed through the steam mixing state, the steam adjusting valve 32
Adjust to close. At the same time, steam bypass system 4
8 steam bypass valve 49 is opened.

(3) High temperature member 33 of the gas turbine 16
After confirming that the cooling medium is 100% cooled air, the steam shutoff valve 31 of the steam supply system 30 is fully closed to perform the operation at the time of load shedding.

In the combined cycle power generation plant 10 shown in FIG. 1, during normal start-up when the operating state of the steam cooling gas turbine 16 changes rapidly, during normal shutdown, when the gas turbine 16 trips the steam turbine 23, and when the load is cut off. In the above, even if the pressure, temperature, and flow rate of the cooling steam from the exhaust heat recovery boiler 13 are insufficient and the steam conditions necessary for cooling the high temperature member 33 of the gas turbine 16 are not satisfied, the auxiliary boiler is not used. In addition, the high temperature member 33 can be sufficiently cooled, and it is possible to prevent the occurrence of excessive thermal stress that impairs the safety of turbine equipment.

Further, in the gas turbine plant 11 provided in the combined cycle power generation plant 10, the cooling air or the drain of the high temperature member 33 of the gas turbine 16 can be converted into the steam supply system 30 and the steam recovery system 34 which are steam systems. It is possible to minimize the mixture of volatile steam, and prevent damage to the steam supply / recovery systems 30 and 34 due to internal corrosion such as oxidation.

Further, the drain generated in the steam supply system 30 and the steam which may generate the drain are drain pipe 5
Since it is discharged to the outside from 0, 51, or is guided from the steam bypass system 48 to the condenser 25 side, it is possible to prevent the drain from being guided to the high temperature member 33 of the gas turbine 16 in advance. Drain, which may be generated in the steam supply system 30, can be reliably prevented from mixing into the high temperature member 33 of 16. Therefore, the high temperature member 33
Drain is not mixed in the cooling part of the above, and the cooling steam path is blocked by the scale adhesion to deteriorate the cooling efficiency, and excessive thermal stress does not occur. If the steam conditions for introducing the steam recovered in the steam recovery system into the steam turbine 23 are not satisfied by the gas turbine plant 11 and the operating method thereof, the steam may be supplied to the steam turbine 23. Moreover, the turbine equipment of the steam turbine 23 is not damaged.

FIG. 3 shows an embodiment of a cogeneration plant equipped with a gas turbine plant according to the present invention.

The cogeneration plant 60 is a plant adapted to generate electricity and supply heat at the same time.
The cogeneration plant 60 shown in FIG. 3 includes a gas turbine plant 11 for generating power, an exhaust heat recovery boiler 13 for recovering exhaust heat from the gas turbine plant 11,
The exhaust heat recovery boiler 13 is provided with an exhaust heat utilization facility 63 for utilizing steam (or hot water supply) for air conditioning and hot water supply in a building 62 or a specific area through a pipeline 61.

The cogeneration plant 60 has a characteristic that, in addition to the effective use of exhaust heat at the time of power generation, the power transmission cost is lower and the energy saving effect is large as compared with the conventional electric power supply system that builds and transmits a huge power plant in a remote place. . The energy efficiency of the cogeneration plant 60 is in the range of 40% even in the combined cycle power generation plant 10, while it reaches 70 to 80%, which is excellent.

Since the gas turbine plant 11 provided in the cogeneration plant 60 shown in FIG. 3 is not different from the gas turbine plant shown in FIG. 1, the same reference numerals are given and description thereof will be omitted.

The gas turbine 16 of the gas turbine plant 11 is a steam cooling gas turbine that uses a part of the superheated steam generated in the exhaust heat recovery boiler 13 as cooling steam. Since the cooling equipment of this gas turbine 16 is substantially the same as the gas turbine plant shown in FIG. 1,
The same reference numerals are given and the description is omitted.

However, the steam system for cooling the high temperature member 33 of the gas turbine 16 is the steam supply system 30 and the steam recovery system 3
4 is common, but since the cogeneration plant 60 is not equipped with a steam turbine plant, the cooling steam recovery destination of the steam recovery system 34 is different from that shown in FIG. The equipment 63. Although FIG. 3 shows an example in which the bypass recovery system 65 branched from the steam recovery system 34 is provided, the bypass recovery system 65 is not always necessary.

Also in this cogeneration plant 60, when the gas turbine plant 11 is normally started or stopped, or when the gas turbine 16 is tripped or unsteady operation is performed when the load is cut off, the combined cycle power plant shown in FIG. Operation control similar to that of the 10 gas turbine plant is performed.

In the embodiment of the present invention, the gas turbine plant is combined cycle power plant 10.
Although the example applied to the or cogeneration plant 60 is shown, the exhaust heat utilization equipment shown in FIG. 3 is applied to the combined cycle power generation plant 10 shown in FIG. 1, and the steam turbine plant 12 and the exhaust heat utilization equipment 63 are used together. Good.
When the steam turbine plant 12 and the exhaust heat utilization equipment 63 are used together, the exhaust heat recovery boiler 13 may be connected to the exhaust heat utilization equipment 63 such as the building 62 via the pipe circulation line and the return line 61. . The steam recovery system 34 and the turbine bypass recovery system 55 (65) of the steam systems 30 and 34 are both connected to the steam turbine plant 12 side.

In the embodiment of the present invention, the cooling air supply system uses the discharge air of the compressor as the cooling medium of the gas turbine, but this is not limited to the discharge air of the compressor. It may be bleed air from an intermediate stage of the compressor, or may be compressed air pumped up from an air pump.

[0103]

In the gas turbine plant and the operating method thereof according to the first and second aspects, the steam generated in the exhaust heat recovery boiler and the cooling air from the cooling air supply system are used as the cooling medium for the high temperature member of the gas turbine. It is possible to switch and use it, and it is possible to select cooling steam and cooling air according to the operating state of the gas turbine, so when the gas turbine plant is normally started, normally shut down, when the gas turbine is tripped or when the load is cut off. Even when the steam pressure, temperature, and flow rate from the exhaust heat recovery boiler are insufficient and the steam conditions required for cooling the high-temperature members of the gas turbine are not satisfied during a sudden change in operating conditions, the auxiliary boiler is unnecessary, The high temperature member of the gas turbine can be sufficiently cooled without using the auxiliary boiler. Since the gas turbine can be cooled sufficiently and efficiently, it does not generate excessive thermal stress that impairs the safety and stability of the turbine equipment, resulting in high reliability.

In the gas turbine plant and the operating method thereof according to claims 3 and 4, the steam generated in the exhaust heat recovery boiler can be used as the cooling medium of the high temperature member of the gas turbine, and the high temperature member of the gas turbine is cooled. When the medium is cooling air or a mixture of cooling air and steam,
Since the cooling medium after cooling the high temperature member was released into the atmosphere,
When a gas turbine plant undergoes a sudden change in operating conditions, it is possible to minimize the mixture of cooling air and steam that may be drained into the steam supply / recovery system, and the steam supply / recovery system is susceptible to internal corrosion such as oxidation. Damage can be effectively prevented, and reliable operation can be performed.

Further, in the gas turbine plant and the operating method thereof according to claims 5 and 6, even when steam is not used as a cooling medium for the high temperature member of the gas turbine,
The steam generated in the exhaust heat recovery boiler can be circulated to the steam recovery system by bypassing the gas turbine from the steam supply system. Is insufficient or unnecessary for cooling the high-temperature parts of the gas turbine, the gas turbine can be bypassed to allow the steam supply / recovery system to flow, and the steam supply / recovery system can be warmed up while draining. It effectively prevents the potentially dangerous steam from being guided to the high temperature member cooling part of the gas turbine, and causes the scale to adhere due to the mixing of drain into the high temperature member cooling part.The scale adheres to block the cooling steam path. Reliable without lowering cooling efficiency or causing excessive thermal stress on the high temperature parts of the gas turbine It becomes as.

Furthermore, in the gas turbine plant and the operating method thereof according to claims 7 and 8, the steam generated in the exhaust heat recovery boiler can be used as a cooling medium for the high temperature member of the gas turbine, and the high temperature of the gas turbine can be used. When recovering the cooling medium after cooling the members to the steam recovery system, the cooling medium is recovered on the steam turbine outlet side by bypassing the steam turbine according to the operating state of the gas turbine.
Even if the steam guided to the cooling steam recovery system does not have the steam condition to be introduced into the steam turbine, the steam turbine can be bypassed, so that damage to turbine equipment can be prevented and reliable and stable operation can be achieved. It will be possible.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a combined cycle power plant including a gas turbine plant according to the present invention.

FIG. 2 is a diagram showing an operation of a main valve at the time of startup provided in the combined cycle power plant.

FIG. 3 is a system diagram showing a cogeneration system including a gas turbine plant according to the present invention.

FIG. 4 is a system diagram showing a typical example of a conventional multi-axis combined cycle power plant.

[Explanation of symbols]

 10 Combined Cycle Power Plant 11 Gas Turbine Plant 12 Steam Turbine Plant 13 Exhaust Heat Recovery Boiler 14 Compressor 15 Gas Turbine Combustor 16 Gas Turbine 17 Generator 18 Fuel Supply System 20 Chimney 22 Main Steam System 23 Steam Turbine 24 Generator 25 Recovery Water tank 26 Condensate water supply system 30 Steam supply system 31 Steam cutoff valve 32 Steam adjustment valve 33 High temperature member 34 Steam recovery system 35 Upstream steam cutoff valve 36 Downstream steam cutoff valve 40 Cooling air supply system 41 Air cutoff valve 42 Air adjustment Valve 45 Cooling medium discharge system 46 Steam blow valve 48 Steam bypass system 49 Steam bypass valve 50,51 Drain piping 52,53 Drain valve 55 Turbine bypass recovery system 56 Steam cutoff valve (steam turbine bypass valve) 60 Cogeneration plant 61 Pipeline 62 building 63 waste heat utilization equipment

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location F02C 7/18 F02C 7/18 E

Claims (8)

[Claims] 1. In a gas turbine plant constituting a combined cycle power generation plant or a cogeneration plant comprising at least a gas turbine, a generator and an exhaust heat recovery boiler, steam generated in the exhaust heat recovery boiler is supplied to a high temperature of the gas turbine. A steam supply system that can be supplied as a cooling medium for a member is provided, and a cooling air supply system is connected in the middle of this steam supply system to bring cooling steam and cooling air as a cooling medium for the gas turbine high-temperature member into the operating state of the gas turbine. A gas turbine plant characterized in that it can be switched and used in accordance with the requirements. 2. A combined cycle power plant or a cogeneration plant comprises at least a gas turbine, a generator and an exhaust heat recovery boiler, and steam generated in the exhaust heat recovery boiler and cooling air from a cooling air supply system are supplied to the gas. It is characterized in that it is selectively used as a cooling medium for the high temperature member of the turbine, and the cooling medium for the high temperature member of the gas turbine is sequentially switched from cooling air to cooling steam or from cooling steam to cooling air according to the operating state of the gas turbine. Operating method of a gas turbine plant. 3. In a gas turbine plant constituting a combined cycle power generation plant or a cogeneration plant, which comprises at least a gas turbine, a generator and an exhaust heat recovery boiler, steam generated in the exhaust heat recovery boiler is heated to a high temperature of the gas turbine. While providing a steam supply system that can be supplied as a cooling medium for the members, a steam recovery system that recovers the steam after cooling the high temperature member of the gas turbine is provided, and the recovery cooling medium can be released to the atmosphere in the middle of this steam recovery system. A gas turbine plant comprising a cooling medium discharge system. 4. A combined cycle power plant or a cogeneration plant is provided with at least a gas turbine, a generator and an exhaust heat recovery boiler, and steam generated in the exhaust heat recovery boiler can be used as a cooling medium for a high temperature member of the gas turbine. A method for operating a gas turbine plant, wherein when the cooling medium for the high temperature member of the gas turbine is a mixture of cooling air and steam or cooling air, the cooling medium after cooling the high temperature member is released into the atmosphere. 5. In a gas turbine plant constituting a combined cycle power generation plant or a cogeneration plant comprising at least a gas turbine, a generator and an exhaust heat recovery boiler, steam generated in the exhaust heat recovery boiler is supplied to a high temperature of the gas turbine. While providing a steam supply system capable of supplying as a member cooling medium, a steam recovery system for recovering steam after cooling the high temperature member of the gas turbine is provided, and a steam bypass system branched from the middle of the steam supply system is used for steam recovery. A gas turbine plant, which is connected to a system and allows cooling steam to flow through a steam supply system and a steam recovery system even when steam is not used as a cooling medium for a high-temperature member of the gas turbine. 6. The combined cycle power plant or cogeneration plant comprises at least a gas turbine, a generator and an exhaust heat recovery boiler, and when steam is not used as a cooling medium for a high temperature member of the gas turbine,
A method of operating a gas turbine plant, characterized in that steam generated in the exhaust heat recovery boiler is passed from a steam supply system to a steam recovery system by bypassing the gas turbine. 7. A gas turbine plant constituting a combined cycle power generation plant or a cogeneration plant comprising at least a gas turbine, a generator and an exhaust heat recovery boiler, and a steam turbine driven by steam generated in the exhaust heat recovery boiler. A steam turbine plant equipped with a steam supply system capable of supplying the steam generated in the exhaust heat recovery boiler as a cooling medium for a high-temperature member of a gas turbine, while the steam after cooling the high-temperature member of the gas turbine is steamed A recoverable steam recovery system is installed in the turbine.This steam recovery system branches the turbine bypass recovery system from the middle, and this turbine bypass recovery system bypasses the steam turbine and is connected to the steam turbine outlet to collect the recovery cooling medium. The recovery destination can be switched between a steam turbine and a condenser. Gas turbine plant characterized by being selected. 8. A combined cycle power plant or cogeneration plant comprises at least a gas turbine, an exhaust heat recovery boiler, a steam turbine and a generator, and steam generated in the exhaust heat recovery boiler is used as a cooling medium for a high temperature member of the gas turbine. When the steam can be used and the steam after cooling the high temperature members of the gas turbine is to be recovered by the steam recovery system, the steam after cooling the gas turbine can be recovered to the steam turbine outlet side by bypassing the steam turbine depending on the operating condition of the gas turbine. A characteristic method of operating a gas turbine plant.