JPH10299508A - Steam cooling type gas turbine combined power generating plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply cooling steam having a rate which is distributed suitably, and moderate a distribution ratio of a cooling steam rate without control by arranging flow rate distributing means which is set beforehand so as to set a distribution ratio of the cooling steam rate on a high temperature part to a suitable value under a specified operating condition. SOLUTION: A tail pipe orifice 31 is arranged on a cooling steam outlet of a tail pipe cooling part 13, a moving blade orifice 33 is arranged on an outlet of a moving blade cooling part 14, and a stationary blade orifice 32 is arranged on an outlet of a stationary blade cooling part 15. A reheater inlet orifice 34 is also arranged on a steam pipe passage (a reheater inlet pipe 42) arranged on an inlet of a reheater 190. In those orifices 31, 32, 33, 34, each of pressure-flow characteristics are suitably set under a gas turbine operating condition on the basis of a trial operation data. A cooling steam rate and a rate of steam which is branched from reheater 10 are suitably distributed by those orifices 31 to 34. It is thus possible to suitably hold a ratio for distributing a cooling steam rate to each cooling part by an elapse without any control on operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust heat boiler in which exhaust heat from a gas turbine is led to a steam turbine, and the steam generated by the exhaust heat boiler drives a steam turbine. The present invention relates to a steam-cooled gas turbine combined cycle power plant configured to cool a high-temperature section.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a conventional steam-cooled gas turbine combined cycle power plant. FIG.
, 100 is a gas turbine power generator, 200 is a steam turbine power generator, and 9 is an exhaust heat recovery boiler.

[0003] Reference numeral 1 denotes a gas turbine of the gas turbine power generator 100, 2 denotes a compressor for compressing air to the gas turbine 1, and 4 denotes combustion for injecting fuel into the compressed air from the compressor 2 to burn it. The unit 3 is a gas turbine generator directly connected to the gas turbine 1. On the other hand, the steam turbine power generation device 200 includes a high-pressure turbine 5, an intermediate-pressure turbine 6, a low-pressure turbine 7, and a steam turbine generator 8 directly connected to the rotors of these turbines. 11 is a superheater provided in the exhaust heat recovery boiler 9, 10 is a reheater, and 12 is a chimney.

A high-pressure steam pipe 49 connects the high-temperature high-pressure steam outlet of the superheater 11 and the steam inlet of the high-pressure turbine 5.
Reference numeral 42 denotes the steam after driving the high-pressure turbine 5,
Is a reheater outlet pipe for guiding the steam heated by the reheater 10 to the steam inlet of the intermediate pressure turbine 6.

[0005] Reference numeral 51 denotes a gas turbine exhaust pipe for guiding the exhaust gas after driving the gas turbine to the exhaust heat recovery boiler 9, and sends the exhaust gas of the gas turbine 1 to the exhaust heat recovery boiler 9 via the exhaust pipe 51. And the superheater 11 and the reheater 10 are heated by the heat of the exhaust gas.

[0006] A gas turbine cooling steam supply pipe 43 branches off from a high pressure turbine outlet pipe 41 connecting the steam outlet of the high pressure turbine 5 and the steam inlet of the reheater 10.
The gas turbine cooling steam supply pipe 43 is connected to the transition piece cooling section 13 via a transition piece steam inlet pipe 44, connected to the moving blade cooling section 14 via a moving blade steam inlet pipe 46, and further connected to the stationary blade steam. It is connected to the stationary blade cooling unit 15 via the inlet pipe 45.

Reference numeral 47 denotes a transition piece steam outlet pipe, which connects the steam outlet of the transition piece cooling section 13 to the reheater exit pipe 50 to the intermediate pressure turbine 6. Reference numeral 48 denotes the bucket cooling unit 1.
4 is a moving blade steam outlet pipe for guiding the steam at the outlet to the reheater 10, and 52 is a stationary blade steam outlet pipe for joining the steam of the outlet of the stationary blade cooling unit 15 to the transition piece steam outlet pipe 47. is there.

Reference numeral 71 denotes a transition piece steam control valve provided on the transition piece steam inlet pipe, 72 denotes a stationary blade steam control valve provided on the stationary blade steam inlet pipe 45, and 73 denotes a moving blade steam inlet pipe. It is a moving blade steam control valve provided. Reference numeral 74 denotes a reheater inlet control valve provided on the reheater inlet pipe 42.

The transition piece steam control valve 71, the stationary blade steam control valve 72, and the moving blade steam control valve 73 control the flow rate of the cooling steam to the transition piece cooling unit 13, the stationary blade cooling unit 15, and the moving blade cooling unit 14, respectively. It is to adjust. The reheater inlet control valve 74 controls the amount of high-pressure exhaust steam to the reheater 10. The opening of each of the control valves 71, 72, 73, 74 is controlled by feedback control via a control device (not shown).

Reference numeral 35 denotes a reheater spray for cooling the reheater 10 when the steam temperature after mixing the reheated steam at the outlet of the reheater 10 and the steam after cooling the gas turbine is higher than a predetermined temperature. Add spray water.

During the operation of the conventional steam-cooled gas turbine combined cycle power plant, the steam after driving the high-pressure turbine 5 is sent to the reheater 10 through the high-pressure turbine outlet pipe 41, and the reheater 10 At this time, the gas is heated and heated by the exhaust gas of the gas turbine 1 introduced from the gas turbine exhaust pipe 51, and sent to the medium-pressure turbine 6 through the reheater outlet pipe 50.

The steam in the high-pressure turbine outlet pipe 41 undergoes expansion work in the high-pressure turbine 6 and is cooled, and a part of this steam is introduced into the gas turbine cooling steam supply pipe 43. The steam in the gas turbine cooling steam supply pipe 43, that is, the cooling steam, is branched into three systems. That is, the cooling steam that has entered the transition piece steam inlet pipe 44 is cooled around the combustor transition piece by the transition piece cooling section 13 and is then led out to the transition piece steam outlet pipe 47.
The cooling steam that has entered the moving blade steam inlet pipe 46 is cooled by the moving blade cooling unit 14 and then led out to the moving blade steam outlet pipe 48. After cooling the stationary blade in the stationary blade cooling unit 15, the stationary blade steam outlet pipe 5
2 is derived.

The cooling steam discharged from the moving blade cooler 14 flowing through the moving blade steam outlet pipe 48 is introduced into the reheater 10, merged with the reheat steam, and led to the reheater outlet pipe 50.

The steam in the stationary blade steam outlet pipe 52 is merged with the transition piece steam outlet pipe 47, and the steam flowing through the transition pipe steam outlet pipe 47, that is, the transition piece cooling section 13 and the stationary blade cooling section 15
Is discharged into the reheat steam flowing through the reheater outlet pipe 50, that is, the reheat steam into which the cooling steam from the rotor blade cooling unit 14 is merged, and is sent to the intermediate-pressure turbine 6.

During the operation of the above-mentioned plant, when the operating conditions of the gas turbine power generator 100 change, the heat loads of the transition piece, the stationary blade, the moving blade, etc., which are the high temperature parts of the gas turbine, change. The flow rate of the cooling steam to the transition piece cooling unit 13, the stationary blade cooling unit 15, and the moving blade cooling unit 14 for cooling these high temperature parts is adjusted by adjusting the opening of the control valves 71, 72, 73 and 74. The plant efficiency is kept high by controlling to an appropriate value.

In this flow rate control, a detection signal of each high-temperature section outlet steam temperature is input to a control device (not shown), and the control device sends an opening control signal to each of the control valves 71, 72, 73 and 74 based on the detection signal. The output is controlled by feedback control in which the opening degree of each control valve is changed according to the change in the heat load.

[0017]

In the conventional steam-cooled gas turbine combined cycle power plant, as described above, the transition piece cooling section 13, the stationary blade cooling section 15, and the moving blade cooling section 14 are used.
The distribution of the amount of cooling steam to each cooling unit is controlled by control valves 71, 72, 73 provided at the inlet of the reheater, and the reheater inlet pipe 41
Controls the total amount of cooling steam to the three cooling units, that is, the amount of cooling steam guided to the cooling steam inlet pipe 43, and the flow rate control based on the detection of the outlet steam temperature of each high-temperature section. It depends on feedback control.

However, during the operation of the plant, the high-temperature portion of the gas turbine 1 is exposed to an extremely high heat load, and when the operation state of the gas turbine generator 100 changes, this heat load follows immediately and rapidly. Change. On the other hand, since each of the control valves 71, 72, 73, 74 operates by feedback control based on detection of a change in steam outlet temperature, a certain time delay is inevitably generated, and the change in the heat load cannot be followed. See

When such a time delay occurs, a shortage of the amount of cooling steam to each of the high-temperature portions 13, 14, and 15 of the gas turbine 1 occurs, thereby causing destruction of the high-temperature portions due to a heat load.

If the time delay is anticipated and the load change rate of the gas turbine generator 100 is planned to be low in advance in order to prevent the occurrence of the trouble due to the time delay, the responsiveness of the entire plant is reduced, and the plant efficiency is reduced. This leads to reduced drivability.

Each of the control valves 71, 72, 73, 7
Reference numeral 4 denotes a control valve provided with a drive device, which has a complicated structure and is more likely to cause a failure than an ordinary manual valve or the like.

An object of the present invention is to provide a system which can be realized without controlling the flow rate to each cooling section where there is a possibility that a time delay may occur with respect to the heat load of a gas turbine. It is not to generate.

[0023]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and the first aspect of the present invention is to introduce waste heat from a gas turbine constituting a gas turbine power generator to a waste heat boiler. The steam turbine is driven by the steam generated by the exhaust heat boiler, and a plurality of high-temperature portions of the gas turbine are cooled by cooling steam using all or a part of the steam for driving the steam turbine. In the gas turbine combined cycle power plant, each of the cooling steam pipes to the plurality of high temperature sections of the gas turbine or the steam pipes for recovering steam from the high temperature sections has a distribution ratio of the amount of cooling steam to each of the high temperature sections. A steam-cooled gas turbine combined cycle power plant is provided with flow rate distribution means preset to have an appropriate value under operating conditions.

In the above means, it is preferable that each of the flow rate distribution means is constituted by a fixed throttle type orifice or a manual open / close valve.

According to the above-mentioned means, a flow rate comprising a fixed throttle type orifice and a manual open / close valve provided in a cooling steam line to each of the cooling sections of the transition piece, the stationary blade, and the moving blade of the gas turbine high temperature section. Since the pressure-flow rate characteristics of the distribution means are properly set in advance based on test operation data and the like, during the operation of the plant, the cooling sections are distributed to the cooling sections by the flow distribution means. Thus, during the operation of the plant, the flow rate of the cooling steam to each cooling section is appropriately maintained to some extent without any control.

Therefore, since no control is performed, there is no time delay in response as in the case where the conventional feedback control is performed. Since the control is not performed, the amount of cooling heat of each part also changes in accordance with the change in the heat load of the gas turbine, but this change is allowed by taking a margin in anticipation of this change.

Also, since the flow distribution means is a device whose structure is extremely simple as compared with a conventional control valve with a driving device, such as a fixed throttle orifice and a manual opening / closing valve, a material having a high temperature strength must be used. This makes it easy to install the flow rate distribution means in each cooling section outlet pipe where the steam temperature becomes high. Therefore, the steam pressure for cooling the high-temperature portion can also be kept high, whereby the minimum pressure set value of the minimum pressure control of the reheater outlet steam pressure can be reduced,
Such a reduction reduces the pressure loss of the reheat steam system.

According to a second aspect of the present invention, the above-mentioned cooling steam pipes are connected to a high-pressure steam outlet pipe through which steam after driving the high-pressure turbine constituting the steam turbine flows. A part or all of the latter steam is supplied to the cooling pipe.

In particular, at this time, the cooling steam supplied to the cooling steam line after driving the high-pressure turbine is set to be a certain amount excessive with respect to the cooling steam amount set to the plurality of high-temperature sections, It is configured to supply all or part of the excess steam to the cooling section of the bucket.

According to this means, excess cooling steam can be sent to each cooler in the high-temperature portion of the gas turbine at an initial stage, which is more than the amount of cooling steam properly distributed by the flow rate distribution means. Can be absorbed by this surplus even when the value of the surplus increases.

In particular, since the rotor blades are under the action of high mechanical stress at high temperatures, the cooling steam for cooling them has a sufficient flow rate in consideration of the variation in the operating conditions of the gas turbine. It is required to secure the temperature, and it is possible to supply a sufficient cooling steam by such means.

Further, the third means of the present invention is configured so that the operation state of the gas turbine is adjusted such that the exhaust gas temperature becomes equal to or lower than a predetermined set temperature at a partial load.

According to such a means, the gas turbine is operated so as to lower the maximum exhaust temperature at the time of the partial load of the gas turbine by a certain amount, thereby reducing the heat load of the high-temperature portion and allowing the flow rate distribution means to cool the cooling steam. Even if the distribution control is not performed, the shortage of the cooling steam amount can be avoided, and a sufficient amount of the cooling steam can be sent to the high-temperature portion.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS. FIG. 1 is a system diagram of a steam-cooled gas turbine combined cycle power plant according to a first embodiment of the present invention. In FIG. 2, 100 is a gas turbine power generator, 200 is a steam turbine power generator, and 9 is an exhaust heat recovery boiler.

Reference numeral 1 denotes a gas turbine of the gas turbine generator 100, 2 denotes a compressor for compressing air to the gas turbine 1, and 4 denotes a combustion for injecting fuel into the compressed air from the compressor 2 to burn it. The unit 3 is a gas turbine generator directly connected to the gas turbine 1. On the other hand, the steam turbine generator 200 includes a high-pressure turbine 5, an intermediate-pressure turbine 6, a low-pressure turbine 7, and a steam turbine generator 8 directly connected to the rotors of these turbines. 11 is a superheater provided in the exhaust heat recovery boiler 9, 10 is a reheater, and 12 is a chimney.

A high-pressure steam pipe 49 connects a high-temperature high-pressure steam outlet of the superheater 11 and a steam inlet of the high-pressure turbine 5.
Reference numeral 42 denotes the steam after driving the high-pressure turbine 5,
Is a reheater outlet pipe for guiding the steam heated by the reheater 10 to the steam inlet of the intermediate pressure turbine 6.

Reference numeral 51 denotes a gas turbine exhaust pipe for guiding the exhaust gas after driving the gas turbine to the exhaust heat recovery boiler 9, and supplies the exhaust gas of the gas turbine 1 to the exhaust heat recovery boiler 9 via the exhaust pipe 51. And the superheater 11 and the reheater 10 are heated by the heat of the exhaust gas.

Next, the system for cooling the gas turbine by the steam from the steam turbine includes a transition piece cooling section 13 of the gas turbine, a shaft end entrance / exit 14 of the moving blade cooling section, and a stationary blade cooling section 15.
Etc.

A gas turbine cooling steam supply pipe 43 branches off from a high pressure turbine outlet pipe 41 connecting the steam outlet of the high pressure turbine 5 and the steam inlet of the reheater 10.
The gas turbine cooling steam supply pipe 43 is connected to the transition piece cooler 13 via a transition piece steam inlet pipe 44, and connected to the rotor blade cooling section inlet 14 via a rotor blade steam inlet pipe 46. The vane steam inlet pipe 45 is connected to the vane cooling section 15.

Reference numeral 47 denotes a transition piece steam outlet pipe, which connects the steam outlet of the transition piece cooling section 13 and the reheater outlet pipe 50 to the intermediate pressure turbine 6. Reference numeral 48 denotes the bucket cooling unit 1.
4 is a moving blade steam outlet pipe for guiding the steam at the outlet to the reheater 10, and 52 is a stationary blade steam outlet pipe for joining the steam of the outlet of the stationary blade cooling unit 15 to the transition piece steam outlet pipe 47. is there. The above configuration is the same as that of the conventional steam-cooled gas turbine combined plant shown in FIG.

In the first embodiment according to the present invention,
Tail cooling unit 13, moving blade cooling unit 14, and stationary blade cooling unit 15
A fixed orifice is provided at the steam outlet of the reheater 10 and at the steam inlet of the reheater 10.

That is, in FIG. 1, reference numeral 31 denotes a transition piece steam outlet orifice (hereinafter abbreviated as transition piece orifice) provided near the exit of the transition piece cooling section 13 of the transition piece steam outlet pipe 47, and 33 denotes the above-mentioned moving blade. Blade cooling unit 14 of steam outlet pipe 48
A moving blade steam outlet orifice (hereinafter abbreviated as moving blade orifice) 32 provided near the outlet is a stationary blade steam outlet orifice (hereinafter referred to as static) provided near the outlet of the stationary blade cooling section 15 of the stationary blade steam outlet pipe 52. Wing orifice).

Reference numeral 34 denotes the high-pressure turbine outlet pipe 41.
The reheater inlet orifice (hereinafter abbreviated as reheat orifice) provided near the reheater 10 inlet. The transition piece orifice 31, the moving blade orifice 33, the stationary blade orifice 32, and the reheating orifice 34 are fixed orifices in which the opening ratio, that is, the pressure-flow rate is set to a predetermined value in advance.

Each of the orifices 31, 32, 33, 34
In the above, the opening ratio, that is, the pressure-flow rate characteristic is such that the transition piece cooling unit 13, the moving blade cooling unit 14, and the stationary blade for cooling high-temperature members such as the transition piece, the moving blade, and the stationary blade of the gas turbine 1. Since it depends on the asymmetry in the routing of the steam pipe to the cooling unit 15, the manufacturing error of each of the high-temperature members, and the variation of the pressure-flow characteristics caused by other factors, the test operation of the plant is usually performed. It is decided by line.

Numeral 35 denotes a reheater spray, which cools the reheat steam when the steam temperature after mixing the reheat steam at the outlet of the reheater 10 and the steam after cooling the gas turbine becomes higher than a predetermined temperature. It is.

As described above, during operation of the combined steam-cooled gas turbine combined cycle power plant, the steam after driving the high-pressure turbine 5 is sent to the reheater 10 through the high-pressure steam outlet pipe 41, In the reheater 10, the gas is heated and heated by the exhaust gas of the gas turbine 1 introduced from the gas turbine exhaust pipe 51, and sent to the medium-pressure turbine 6 through the reheater outlet pipe 50.

The steam in the high-pressure turbine outlet pipe 41 performs expansion work in the high-pressure turbine 5 and is cooled, and a part of this steam is introduced into the gas turbine cooling steam supply pipe 43.

The steam in the gas turbine cooling steam supply pipe 43, that is, the cooling steam, is branched into three systems. That is, the cooling steam that has entered the transition piece steam inlet pipe 44 is cooled around the transition piece by the transition piece cooling unit 13 and then led out to the transition piece steam outlet pipe 47.
The cooling steam entering the moving blade steam inlet pipe 46 cools the moving blades in the moving blade cooling unit 14, and then is led out to the moving blade steam outlet pipe 48, and further enters the stationary blade steam inlet pipe 45. Is cooled to the stationary blade steam outlet pipe 52 after the stationary blade is cooled by the stationary blade cooling unit 15.

The cooling steam discharged from the moving blade cooler 14 flowing through the moving blade steam outlet pipe 48 is introduced into the reheater 10, merged with the reheat steam, and led to the reheater outlet pipe 50.

The steam in the stationary blade steam outlet pipe 52 is merged with the transition piece steam outlet pipe 47, and the steam flowing through the transition pipe steam outlet pipe 47, that is, the transition piece cooler 13 and the stationary blade cooler 15
Is discharged into the reheat steam flowing through the reheater outlet pipe 50, that is, the reheat steam into which the cooling steam from the moving blade cooler 14 is merged and sent to the intermediate pressure turbine 6.

In the rated operation state, the transition piece cooling section 13,
Adjusting the steam amount of the cooling steam to the moving blade cooling unit 14 and the stationary blade cooling unit 15 can be set by adjusting the inlet of the intermediate pressure turbine 6, that is, the reheat steam temperature after the cooling steam confluence is equal to or higher than a predetermined temperature. To maintain the plant efficiency at a high level.

Further, in this embodiment, the transition piece orifice 31 is provided at the outlet of the cooling steam of the transition piece cooling section 13, the moving blade orifice 33 is provided at the exit of the moving blade cooling section 14, and the stationary blade orifice 32 is provided at the exit of the stationary blade cooling section 15. Are set up respectively,
A reheat orifice 42 is also provided in the steam line at the inlet of the reheater 10 (reheater inlet pipe 42).

The orifices 31, 32,
As described above, the pressure-flow characteristics 33 and 34 are appropriately set under the gas turbine operating conditions based on the test operation data, so that the transition piece cooling unit 13 and the moving blade cooling unit 1
4. The amount of cooling steam sent to the vane cooling section 15 is appropriately distributed by the transition piece orifice 31, the moving blade orifice 33, and the vane orifice 32, respectively.
The amount of steam diverted as cooling steam from the steam to the reheater 10 after driving to the gas turbine cooling steam supply pipe 43 is also appropriately distributed by the reheating orifice 34.

Here, when the operating conditions of the plant change, such as the partial load operation of the gas turbine generator 100 or the steam turbine generator 200, the above-mentioned coolers 13 and
The distribution ratio of the cooling steam to the cooling steam 14 and 15 and the ratio of the cooling steam separated from the reheating steam to the reheater 10 are determined by the process because no control is performed during the operation.
There is no problem because it falls within the allowable range.

Therefore, in this embodiment, since no control is performed, there is no delay in response as in feedback control, and operation control with high responsiveness can be realized.

The orifices 31, 32, 3
Since the orifices 3 and 34 are fixed orifices, the structure is simpler than that of a conventional control valve with a driving device, and it is easy to use a material having high strength at high temperature. Therefore,
The orifices can be installed in the outlet pipes where the cooling steam temperatures of the cooling units 13, 14, and 15 are high, so that the transition piece, the moving blade, the stationary blade, and the like of the gas turbine power generator 100 can be installed. The pressure on the cooling steam side of the high temperature section can be kept high.

However, in order to prevent the working gas from leaking from the gas side of the gas turbine 1 to the cooling steam side, the steam pressure at the inlet of the intermediate pressure turbine 6, ie, the steam at the outlet of the reheater 10 and the cooling steam are mixed. Although the minimum pressure control of the steam pressure is performed, in the embodiment of the present invention, as described above, the pressure on the cooling steam side can be kept higher than that of the conventional one, so that the minimum pressure in the minimum pressure control is controlled. The set value can be lower than the conventional one.

Therefore, the pressure loss of the reheat steam system is reduced by lowering the minimum pressure set value in the minimum pressure control of the intermediate-pressure turbine inlet steam pressure, and the thermal efficiency of the plant at a partial load is improved.

If the steam temperature after mixing the reheated steam at the inlet of the intermediate-pressure turbine 6 and the cooling steam after cooling the high-temperature portion of the gas turbine 1 exceeds a predetermined temperature, the reheater spray 35 Is operated to lower the steam temperature to a predetermined temperature, and keep the steam temperature at the inlet of the intermediate-pressure turbine 6 within a set value.

FIG. 2 is a system diagram of a steam-cooled gas turbine combined cycle power plant according to a second embodiment of the present invention. In this embodiment, a manual opening / closing valve, that is, a manual valve is provided in place of the fixed orifice of the fixed throttle type in the first embodiment.

That is, in FIG. 2, reference numeral 61 denotes a transition pipe steam outlet manual valve (hereinafter abbreviated as transition pipe manual valve) provided at the exit of the transition pipe cooling section 13 of the transition pipe steam outlet pipe 47, and 62 denotes stationary vane steam. A stationary blade steam outlet manual valve (hereinafter abbreviated as a stationary blade manual valve) provided at the outlet of the stationary blade cooling unit 15 of the outlet pipe 52, and a stationary blade steam outlet valve 63 provided at the exit of the bucket cooling unit 14 of the rotor blade steam outlet pipe 48. It is a moving blade steam outlet manual valve (hereinafter abbreviated as a moving blade manual valve).
Reference numeral 64 denotes a reheater inlet manual valve provided in the reheater inlet pipe 42.

The manual valves 61, 62, 63, 64 are
As in the case of the orifice in the first embodiment, the pressure-flow characteristics are properly set at the beginning of the operation based on the test operation data of the plant. Other configurations are the same as those of the first embodiment, and the same members are denoted by the same reference numerals.

In this embodiment, a manual valve 6 whose opening can be freely adjusted is provided in the cooling steam line and the reheating steam line.
Since 1, 62, 63, and 64 are provided, the initial opening degree of these manual valves, that is, the flow rate distribution of steam passing through each manual valve can be easily made based on the test operation data of the plant. Further, even when the flow rate distribution does not reach the predetermined distribution during operation, the respective manual valves 61, 62, 63, 64 are also used.
Can be easily adjusted to an appropriate distribution.

Further, the transition piece manual valve 61, the stationary blade manual valve 62, the moving blade manual valve 63, and the reheater inlet valve 64 have a simple structure in which the fixed orifice is a variable throttle orifice and have a simple structure such as a poppet valve. As described above, a strict shut-off property (complete closing of the seat surface) is not required, so that a low-cost manual valve having a simple structure can be used, and the product cost is greatly reduced as compared with a conventional control valve.

The manual valves 61, 62, 63, 64
Since the structure is simple as described above, similarly to the fixed orifice, it can be easily configured with a member having a high strength at high temperature, and can be installed in the outlet steam line, similar to the first embodiment. In addition, an improvement in plant thermal efficiency due to a decrease in the minimum pressure set value at the inlet of the intermediate pressure turbine 6 can be realized.

FIG. 3 is a system diagram of a steam-cooled gas turbine combined cycle power plant according to a third embodiment of the present invention. In the present embodiment, the entire amount of steam at the outlet of the high-pressure turbine 5 is supplied as cooling steam for the high-temperature portion of the gas turbine 1.

That is, in FIG. 3, the high pressure turbine outlet pipe 41 from the outlet of the high pressure turbine 5 is connected to the reheater 10 as in the first embodiment (FIG. 1) and the second embodiment (FIG. 2). Without being connected to the transition piece steam inlet pipe 44, the stationary blade steam inlet pipe 45, and the moving blade steam inlet pipe 46, they are branched.

Accordingly, the reheater inlet pipe 42 and the reheater inlet orifice 34 or the reheater inlet manual valve 64 installed in the reheater inlet pipe 42 in the first and second embodiments are eliminated, while the first embodiment is replaced with the first embodiment. Similarly to the above, the transition piece orifice 31 is provided at the exit of the transition piece cooling section 13, the stationary blade orifice 32 is provided at the exit of the stationary blade cooling section 15, and the moving blade orifice 3 is provided at the exit of the bucket cooling section 14.
3 are provided respectively.

Instead of the transition piece orifice 31, the stationary blade orifice 32, and the moving blade orifice 33, similarly to the second embodiment, a transition piece manual valve 61, a stationary blade manual valve 62, and a moving blade manual valve 63 are respectively provided. It may be provided.

The initial adjustment procedure of each of the orifices 31, 32, 33 or the manual valves 61, 62, 63 (see FIG. 2) is the same as in the first or second embodiment.

In this embodiment, the transition piece cooling section 13
The relatively high-temperature steam that has passed through the stationary blade cooling unit 15 is directly introduced into the intermediate-pressure turbine 6 through the transition piece steam outlet pipe 47. The relatively low-temperature steam that has passed through the bucket cooling unit 14 is returned to the reheater 10 through the bucket steam outlet pipe 48 and is heated by the reheater 10. Blade cooling unit 15
And is introduced into the intermediate-pressure turbine 6 to perform expansion work. Structures other than the above are the same as those of the first embodiment shown in FIG. 1 or the second embodiment shown in FIG. 2, and the same members are denoted by the same reference numerals.

Here, as in the first to third embodiments of the present invention, the flow rate of the cooling steam for cooling the high-temperature portion of the gas turbine 1 is not controlled by feedback control or the like, but is set at an initial stage. In the control system, an excessive amount of the cooling steam is supplied in advance to the high-temperature portion of the gas turbine 1, and the surplus steam is provided as a replenishment, that is, a buffer when the heat load of the gas turbine increases unexpectedly. Is preferred.

In particular, the rotor blades of the gas turbine 1, which rotates at high speed in a high-temperature gas, need to sufficiently suppress the increase in the heat load due to the strength limitation, so that the instantaneous shortage of the cooling steam is not allowed. I'm left. Therefore, it is desired that the surplus of the cooling steam to the gas turbine 1 be supplied to the moving blade cooling unit 14 that cools the moving blade. Therefore, the steam temperature at the exit of the moving blade cooling unit 14 becomes lower than the allowable temperature limited by the strength of the moving blade material by the increased amount of the cooling steam. The amount corresponding to the reduced temperature is a margin for the time when the cooling steam amount is reduced.

The cooling steam to the transition piece cooling unit 13 and the stationary blade cooling unit 15 is supplied to each of the fixed orifices 31 and 31 so that an appropriate amount of cooling steam is supplied at the rated load of the plant.
32 or the flow rate is adjusted by the manual valves 61 and 62, the temperature of the cooling steam outlet from each of the cooling units 13 and 15 (the temperature of the cooling steam flowing through the transition piece steam outlet pipe 47) is controlled by the medium-pressure turbine 6. At the inlet, the temperature can be raised to a predetermined set temperature.

The cooling steam outlet temperature of the moving blade cooling unit 14 is lower than the outlet temperature of the transition piece and the stationary blade coolers 13 and 15. By guiding to the reheater 10 through the outlet pipe 48 and heating it together with the reheated steam, the temperature can be raised to a predetermined set temperature at the inlet of the intermediate pressure turbine 6.

Further, for some reason, the blade cooling unit 1
When the amount of cooling steam to the cooling blade 4 decreases, the temperature of the cooling steam at the outlet of the blade cooling unit 14 increases, thereby increasing the inlet temperature and the outlet temperature of the reheater 10.
Is operated to lower the temperature, and the steam temperature at the outlet of the reheater 10, that is, at the inlet of the intermediate-pressure turbine 6, is maintained at the set temperature.

FIG. 4 shows an operation diagram of the plant according to the present invention. In this embodiment, the gas turbine 1
The distribution of the flow rate of the cooling steam to each cooling section that cools the high-temperature section of the gas turbine is determined by the fixed orifice or the manual valve, and when the control accompanying the change of the operating state is not performed, the heat of the gas turbine 1 under all the operating conditions The gas turbine is operated so as to lower the gas turbine exhaust temperature in advance in order to secure a sufficient amount of cooling steam with respect to the load.

That is, in the gas turbine load / exhaust temperature diagram shown in FIG. 4, in the prior art, the operation of the gas turbine 1 is performed on the ABCDEF line, temperatures T ₁ was about 630 ° C.. In such a conventional operation mode, the gas turbine exhaust temperature rises between C and D and the like, and the heat load of the high-temperature portion such as the transition piece, the stationary blade, and the moving blade also increases, as in the first to third embodiments. If the distribution control of the cooling steam is not performed, there is a possibility that the amount of the cooling steam may not be sufficient when the operation state suddenly changes.

In order to avoid the occurrence of such a state, in this embodiment, the maximum exhaust gas temperature at the time of partial load is lowered to a constant temperature T ₂ (for example, 600 ° C.), and ABZE is shown in FIG. Operate the gas turbine in the line -F.

By performing the exhaust gas temperature lowering operation, the shortage of the cooling steam amount as described above is avoided. In this way, a sufficient amount of cooling steam can be supplied to each cooling unit without installing a fixed throttle orifice or a manual valve in the cooling steam line and without any particular control.

[0081]

The present invention is configured as described above.
According to the first to third aspects of the present invention, a fixed throttle type orifice, a manual valve, and the like are provided in a cooling steam line to each of the cooling sections of the transition piece, the stationary blade, and the moving blade of the gas turbine high temperature section. Since the pressure-flow characteristics of the flow distribution means are properly set in advance based on the test operation data and the like, during the operation of the plant, the cooling steam of the amount appropriately distributed by the flow distribution means is sent to each cooling unit. In other words, during the operation of the plant, the distribution ratio of the amount of cooling steam to each cooling section can be appropriately maintained without any control.

Therefore, since the control is not performed, there is no time delay in response as in the conventional feedback control. Instead, the temperature of the steam at the outlet and the amount of cooling heat in each high-temperature portion are determined. However, this point can be absorbed by flowing an excessive amount of steam in advance or operating the gas turbine with a reduced heat load.

Further, since the structure of the flow distribution means is simpler than that of a conventional electromagnetic control valve such as a fixed throttle type orifice and a manual on-off valve, it is possible to use a material having high strength at high temperature, It becomes possible to install the above-mentioned flow distribution means in each cooling part outlet pipe where the temperature becomes high. Accordingly, the steam pressure for cooling the high-temperature portion can be kept high, whereby the minimum pressure set value of the minimum pressure control of the reheater outlet steam pressure can be reduced, and the pressure loss of the reheat steam system is reduced by such reduction. And the plant efficiency is improved.

According to the fourth and fifth aspects of the present invention, a sufficient margin can be secured instead of not performing the control.

In particular, since strong stress such as centrifugal force caused by high-speed rotation while being exposed to a high heat load is applied to the rotor blade, the structure as in claim 5 is sufficient to cope with the high stress. Can supply a sufficient amount of cooling steam.

Further, according to the present invention, by operating the gas turbine so as to lower the maximum exhaust gas temperature at the time of partial load of the gas turbine, the heat load of the high temperature portion is reduced, and the flow rate distribution means is used. Shortage of the amount of the cooling steam can be avoided even without performing the distribution control of the cooling steam, and the cooling steam can be sent to the cooler in the high-temperature portion with a margin.

[Brief description of the drawings]

FIG. 1 is a system diagram of a steam-cooled gas turbine combined cycle power plant according to a first embodiment of the present invention.

FIG. 2 is an equivalent view of FIG. 1 showing a second embodiment of the present invention.

FIG. 3 is an equivalent view of FIG. 1 showing a third embodiment of the present invention.

FIG. 4 is a gas turbine operation diagram showing a fourth embodiment of the present invention.

FIG. 5 is a system diagram of a conventional steam-cooled gas turbine combined plant.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Gas turbine generator 200 Steam turbine generator 1 Gas turbine 2 Compressor 3 Gas turbine generator 4 Combustor 5 High-pressure turbine 6 Medium-pressure turbine 7 Low-pressure turbine 8 Steam turbine generator 9 Waste heat recovery boiler 10 Reheater 11 Superheater 13 Tail Tube Cooling Unit 14 Rotor Blade Cooling Unit 15 Stator Blade Cooling Unit 31 Tail Tube Steam Outlet Orifice 32 Stator Blade Steam Outlet Orifice 33 Moving Blade Steam Outlet Orifice 34 Reheater Inlet Orifice 35 Reheater Spray 41 High Pressure Turbine Outlet Pipe 42 Reheater inlet pipe 43 Gas turbine cooling steam supply pipe 44 Tail steam inlet pipe 45 Stator blade steam inlet pipe 46 Moving blade steam inlet pipe 47 Tail pipe steam outlet pipe 48 Moving blade steam outlet pipe 49 High pressure steam pipe 50 Reheater Outlet pipe 51 Gas turbine exhaust pipe 52 Stator vane steam outlet pipe 61 Tailpiece steam outlet manual valve 6 Stationary blade steam outlet manual valve 63 moving blade steam outlet manual valve 64 reheater inlet manual valve

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI F22B 1/18 F22B 1/18 CE

Claims (6)

[Claims] An exhaust heat from a gas turbine constituting a gas turbine power generation device is guided to an exhaust heat boiler, and a steam turbine is driven by steam generated by the exhaust heat boiler, and branched from an appropriate position of the boiler and the turbine. In a gas turbine combined cycle power plant that supplies cooled steam to a plurality of high-temperature sections of the gas turbine, the steam is recovered from a cooling steam line to the plurality of high-temperature sections of the gas turbine or from the high-temperature section. Each of the steam pipes to be provided is provided with flow rate distribution means set in advance so that the distribution ratio of the cooling steam amount to each of the high-temperature portions has an appropriate value under a certain operating condition. Cooled gas turbine combined cycle power plant. 2. The combined steam-cooled gas turbine power plant according to claim 1, wherein said flow rate adjusting means is a fixed throttle type orifice. 3. The combined steam-cooled gas turbine power plant according to claim 1, wherein each of the flow distribution means is a manual on-off valve. 4. Each of the cooling steam pipes is connected to a high pressure turbine outlet pipe through which the steam after driving the high pressure turbine constituting the steam turbine flows, and part or all of the steam after driving the high pressure turbine is discharged. The combined steam-cooled gas turbine power plant according to any one of claims 1 to 3, configured to be supplied to the cooling pipeline. 5. The cooling steam after driving the high-pressure turbine, which is supplied to the cooling steam pipe, is set to a certain amount excess with respect to the cooling steam amount set to the plurality of high-temperature sections, The combined steam-cooled gas turbine power plant according to claim 4, wherein all or a part of the steam turbine is supplied to a cooling unit of the rotor blade. 6. The steam-cooled gas according to claim 1, wherein an operation state of the gas turbine is adjusted such that an exhaust gas temperature is equal to or lower than a predetermined set temperature at a partial load. Turbine combined cycle power plant.