JP2690566B2 - Combined power plant - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a combined cycle power plant, and is particularly suitable for generating steam for driving one steam turbine by utilizing a plurality of heat sources having different exhaust heat conditions. Complex power plant.

[Prior Art] FIG. 15 is a configuration diagram of a conventional combined cycle power plant.
This combined cycle power plant does not show two gas turbines 1 and 2 as heat sources, exhaust heat recovery boilers 3 and 4 provided for each gas turbine, and steam from each exhaust heat recovery boiler 3 and 4 It is composed of one steam turbine 5 driven by the steam collected by the steam header and joined. In a conventional combined cycle power plant, multiple gas turbines 1 and 2 of the same type are used, so the exhaust heat conditions such as the gas temperature and the amount of exhaust gas discharged from each gas turbine 1 and 2 are the same. Is. Therefore, the boilers 3 and 4 that recover the exhaust heat from the exhaust gas also use the same configuration.

As long as the same type of gas turbine is used,
As shown in Fig. 15, the steam generated by using the same heat recovery boiler with the same bank structure can be used by combining it with the steam header. However, for example, when one of the gas turbines used in the conventional combined cycle power plant is replaced with the latest one, the latest gas turbine has higher performance than the conventional one, and its exhaust heat Conditions differ from other gas turbines.

Hereinafter, a case where the gas turbine A having an exhaust gas temperature of 600 ° C., the gas turbine B having an exhaust gas temperature of 500 ° C., and the exhaust heat recovery boilers a and b provided for each gas turbine are of a single pressure type will be described.

In the single-pressure type exhaust heat recovery boiler, a superheater, an evaporator, and a economizer are arranged in sequence from the upstream side in the exhaust gas flow direction, and saturated steam generated in the evaporator is heated to a predetermined temperature by the superheater. . The steam temperature at the outlet of the superheater is determined mainly by the exhaust gas temperature of the gas turbine, the temperature difference from the exhaust gas temperature, and the plant thermal efficiency. Generally, the higher the steam temperature, the higher the plant thermal efficiency, but in order to raise the steam temperature, it is necessary to reduce the difference between the gas turbine exhaust gas temperature and the steam temperature at the superheater outlet. That is, it is necessary to increase the heat transfer area of the superheater, which increases the manufacturing cost of the exhaust heat recovery boiler. Therefore, the steam temperature at the outlet of the superheater is selected so that the plant thermal efficiency is high in the economical range.

Assuming that the optimum temperature difference between the gas turbine exhaust gas temperature and the superheater outlet steam temperature is 50 ° C, the exhaust gas temperature of the gas turbine A is 600 ° C, so the superheater outlet steam temperature of the exhaust heat recovery boiler a is 550 ° C. Becomes Further, since the exhaust gas temperature of the gas turbine B is 500 ° C., the superheater outlet steam temperature of the exhaust heat recovery boiler b is 450 ° C. However, when introducing the steam generated in the two exhaust heat recovery boilers a and b into one steam turbine, it is general to make the temperatures of both steams the same. Therefore, the superheater outlet steam temperature must be adjusted to the lower exhaust gas temperature, and in this example, the steam temperature is 450 ° C. That is, although there is a high-temperature heat source with an exhaust gas temperature of 600 ° C., the steam temperature is set to a low temperature of 450 ° C., which causes a problem that the plant thermal efficiency is deteriorated.

Therefore, for example, JP-A-58-82006 and U.S. Pat.
As described in JP-A-88-979, one exhaust heat recovery boiler is used, and heat from a plurality of heat sources is used to generate steam in the exhaust heat recovery boiler. As described above, in addition to the exhaust heat recovery boiler, another heat source for heating steam is provided.

[Problems to be Solved by the Invention] When an exhaust heat recovery boiler is not provided for a heat source and only one unit is provided, the structure of this one exhaust heat recovery boiler is all heat sources used in the combined cycle power plant. It will be designed according to. That is, there is a problem in that it is designed for each individual combined cycle power plant and lacks versatility. Moreover, when using this exhaust heat recovery boiler, there is a problem that the flexibility in operating the plant is sacrificed because the exhaust gas conditions differ from the conditions in the boiler design unless all heat sources are started.

In addition to the exhaust heat recovery boiler, it is disadvantageous in terms of cost to prepare another heat source for making the steam temperature the same.

An object of the present invention is to provide an exhaust heat recovery boiler corresponding to a heat source without sacrificing flexibility in plant operation,
Moreover, it is an object of the present invention to provide a combined power generation plant that generates steam for driving one steam turbine by a heat source such as a gas turbine having different exhaust heat conditions without providing another heat source.

[Means for Solving the Problems] The above object is to configure a cycle with a plurality of exhaust heat recovery boilers and one steam turbine, and to provide the uppermost stream of the exhaust heat recovery boiler into which the hottest exhaust gas flows. This is achieved by the configuration in which the steam heated by the provided superheater is supplied to the steam turbine.

[Operation] In the present invention, before passing through the superheater provided in the most upstream part of the exhaust heat recovery boiler into which the hottest exhaust gas flows, the preheated feed water or the saturated steam generated in the evaporator is joined, Since it is finally heated by the superheater and then supplied to the steam turbine, the superheater outlet steam temperature can be set according to the temperature of the exhaust gas heat source having the highest temperature, and the thermal efficiency of the plant is not lowered.

〔Example〕

Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a configuration diagram of a combined cycle power plant according to a first embodiment of the present invention. In this embodiment, two gas turbines 1 and 2 of different models, two exhaust heat recovery boilers 3 and 4 of different bank configurations provided for each gas turbine, and one steam turbine 5 are used. It is configured. This combined cycle power plant is an example of a non-reheat single pressure type system. The exhaust gas temperature of the gas turbines 1 and 2 is assumed to be higher in the gas turbine 1 than in the gas turbine 2.

The gas turbines 1 and 2 respectively suck air 6 from the atmosphere, compress it with a compressor 7, and send high-pressure air to the combustor 8. On the other hand, the fuel 9 is supplied to the combustor 8 and the compressor 7
Fuel is burned by the high-pressure air supplied from the fuel cell, and becomes high-temperature and high-pressure gas. The high-temperature and high-pressure gas drives the gas turbine 10, and the gas turbine 10 drives the generator 11 to generate an electric output. The high-temperature gas turbine exhaust gas 12 that has worked in the gas turbine 10 is the exhaust heat recovery boiler in the downstream, respectively.
After being sent to 3, 4 and recovering the sensible heat as steam,
It is released to the atmosphere as low temperature exhaust gas 13.

On the other hand, a water supply pump 14 supplies water supply 15 to the exhaust heat recovery boilers 3 and 4. Water supply 15 consists of two waste heat recovery boilers 3,4
It branches at the inlet and is sent to the economizer 16 of each of the exhaust heat recovery boilers 3 and 4, where it heats by exchanging heat with the exhaust gas to become high-temperature water. 2
The high-temperature water discharged from one economizer 16 merges at the outlet of the economizer 16 of the exhaust heat recovery boiler 4, and is sent to the evaporator 17 of the exhaust heat recovery boiler 4. The high-temperature water sent to the evaporator 17 is heated by the exhaust gas, becomes saturated steam, and is sent to the superheater 18 of the exhaust heat recovery boiler 3. The saturated steam is heated by the superheater 18 to become superheated steam and is sent to the steam turbine 5 as main steam 19.

The main steam 19 drives the steam turbine 5 and then is sent to the condenser 20, while the steam turbine 5 drives the generator 21 to generate an electric output. The steam sent to the condenser 20 is cooled by the cooling water and condensed into water, which is supplied again to the exhaust heat recovery boilers 3 and 4 by the water supply pump 14.

When starting the combined cycle power plant according to this embodiment, the water supply pump 14 is turned on and both gas turbines 1 and 2 are started. When the pressure of the steam liquefied in the coal economizer 16 by the exhaust gas 12 of the gas turbine and vaporized in the evaporator 17 exceeds a predetermined value, the vapor is transferred from the evaporator 17 to the superheater 18 of the boiler 3 by a valve (not shown). And is heated by the superheater 18 and supplied to the steam turbine 5 as main steam. As a result, the steam turbine 5 starts rotating.

FIG. 2 is a configuration diagram of a combined cycle power plant according to a second embodiment of the present invention. Similar to the first embodiment, this combined cycle power plant has two gas turbines 1 and 2 of different types, and two exhaust heat recovery boilers 3 and 4 of different bank configurations provided for each gas turbine. It is composed of one steam turbine 5 and is an example of a non-reheat single pressure type system. or,
As in the first embodiment, the exhaust gas temperature of the gas turbines 1 and 2 is assumed to be higher in the gas turbine 1 than in the gas turbine 2. In each of the embodiments described below, it is assumed that the gas turbine 1 has a higher exhaust gas temperature than the gas turbine 2.

The difference between the second embodiment and the first embodiment is that an evaporator 17 is also installed in the exhaust heat recovery boiler 3, and the feed water preheated by the economizer 16 of the boiler 3 is sent to the evaporator 17 of the boiler 3. Water supplied from the economizer 16 of the boiler 4 is supplied to the evaporator 17 of the boiler 3.
The steam generated in both evaporators 17 is sent to the superheater 18 of the boiler 3.

In other words, the present embodiment is the same in that a plurality of exhaust heat recovery boilers 3 and 4 having different bank configurations constitute one cycle, and a superheater is installed in the exhaust heat recovery boiler 3 into which higher-temperature exhaust gas flows. However, it differs from the first embodiment in that an evaporator 17 is installed in each of the exhaust heat recovery boilers 3 and 4.
Which of the first embodiment and the second embodiment is adopted is selected according to the difference in the exhaust gas temperature and the exhaust gas amount of the two gas turbines, and the optimum system is used for these conditions.

When activating the combined cycle power plant according to this embodiment, preferably, both gas turbines 1 and 2 are simultaneously activated after activating the water supply pump 14, as in the first embodiment. When the steam pressure of the steam generated in each evaporator 17 in each boiler 3 and 4 becomes equal to or higher than a predetermined pressure, the steam flows into the superheater 18 through a valve (not shown) that is opened by the steam pressure, and the steam heated here is The steam is supplied to the steam turbine 5 as main steam, and the steam turbine 5 starts rotating.

Here, the difference in steam cycle thermal efficiency will be described with reference to the second embodiment and the conventional example shown in FIG. When the steam cycle thermal efficiency is defined as the ratio of the steam turbine output to the heat input to the exhaust heat recovery boiler, the steam cycle thermal efficiency K (%) is shown by the following.

As conditions for the study, the exhaust gas temperature of the gas turbine A is 600 ° C, the exhaust gas temperature of the gas turbine B is 500 ° C, the exhaust gas amount is the same for both gas turbines A and B, and the temperature difference between the exhaust gas and the superheater outlet steam is the same. Is a minimum of 50 ° C, and the main steam pressure is
Assume 50 atg.

In the conventional example shown in FIG. 15, since the superheater outlet steam temperature is restricted by the gas turbine B having a low exhaust gas temperature, the superheater outlet steam temperature is 450 ° C. from the above assumption. or,
In the second embodiment, since the superheater outlet steam temperature is determined only by the exhaust gas temperature of the gas turbine A, the superheater steam temperature is 550 ° C.

When the steam cycle thermal efficiency K is calculated under the above conditions, the steam cycle thermal efficiency of the cycle of the second embodiment is improved by about 2.7% relative to the cycle of the conventional example.

Next, a combined cycle power plant according to a third embodiment of the present invention will be described with reference to FIG.

This embodiment is an example of a non-reheat double pressure type system, whereas the first and second embodiments are non-reheat single pressure type system examples. The main engine configuration of the combined cycle power plant of this embodiment is the first and second
Although it is the same as the embodiment, it is different from the above embodiment in that the drum pressure levels of the exhaust heat recovery boilers 3 and 4 are different and that the steam turbine 5 is a mixed pressure type.

In this embodiment, the exhaust heat recovery boiler 3 is composed of a superheater 18, an evaporator 17 and a economizer 16, and the exhaust heat recovery boiler 4 is composed of an evaporator 17 and a economizer 16. Recovery boiler 4
The drum pressure level of the evaporator 17 is set higher than the drum pressure level of the evaporator 17 of the exhaust heat recovery boiler 3.

Water supply pump 14 supplies water 15 to exhaust heat recovery boilers 3 and 4.
Is supplied. The feed water 15 is branched at two inlets of the exhaust heat recovery boilers 3 and 4, and is sent to the economizers 16 of the exhaust heat recovery boilers 3 and 4, respectively. The water supplied to the economizer 16 of the exhaust heat recovery boiler 4 is
Evaporator of boiler 4 by being heated by exhaust gas to become high temperature water
It is sent to 17 and further heated in the evaporator 17 to become high-pressure saturated vapor. This high-pressure saturated steam is sent to the superheater 18 of the exhaust heat recovery boiler 3 and heated to become superheated steam, which is the main steam.
19 is supplied to the high pressure part of the steam turbine 5.

On the other hand, the feed water sent to the economizer 16 of the exhaust heat recovery boiler 3 becomes high-temperature water in the economizer 16, and is sent to the evaporator 17 of the boiler 3. In the evaporator 17 of the boiler 3, relatively low-pressure saturated steam is generated and introduced as a low-pressure steam 22 into the middle section of the steam turbine 5.

The main steam 19 and the low-pressure steam 22 drive the steam turbine 5, and then are sent to the condenser 20, while the steam turbine 5 is a generator.
It drives 21 to generate an electrical output. This embodiment also has the same effect as the above-mentioned embodiment. In addition, various examples will be described below.
This is the same as the embodiment.

FIG. 4 is a configuration diagram of a combined cycle power plant according to a fourth embodiment of the present invention.

Similar to the third embodiment, this embodiment is an example of a non-reheat double pressure type system, but the exhaust heat recovery boilers 3, 4 having two superheaters are provided.
It is different in that it is installed in each of. Exhaust heat recovery boiler 3
Is composed of a secondary superheater 23, an evaporator 17 and a economizer 16,
The exhaust heat recovery boiler 4 includes a primary superheater 24, an evaporator 17, and a economizer 16.
The steam generated in the evaporator 17 of the boiler 4 is first heated by the superheater 24 of the boiler 4, and then heated by the superheater 23 of the boiler 3 to become the main steam 19. The drum pressure level of the evaporator 17 of the exhaust heat recovery boiler 4 is set higher than the drum pressure level of the evaporator 17 of the exhaust heat recovery boiler 3.

FIG. 5 is a configuration diagram of a combined cycle power plant according to a fifth embodiment of the present invention.

This embodiment is similar to the third embodiment shown in FIG.
25 is additionally installed in the boiler 3. When the pressure difference between the steam temperature inside the steam turbine and the temperature of the saturated steam mixed in the mixed pressure section of the steam turbine 5 is too large to mix the pressure (when the pressure in the mixed pressure section is high), the mixed pressure steam is mixed. By heating with the low-pressure superheater 25, mixed pressure becomes possible.

FIG. 6 is a configuration diagram of a combined cycle power plant according to a sixth embodiment of the present invention. In this embodiment, a low pressure superheater 25 similar to that of the fifth embodiment is additionally installed in the fourth embodiment shown in FIG.

FIG. 7 is a configuration diagram of a combined cycle power plant according to a seventh embodiment of the present invention.

Like the third to sixth embodiments, the present embodiment is an example of a non-reheat double pressure type system, but is different in that one evaporator and one economizer are additionally installed in the boiler 3. different. That is, the exhaust heat recovery boiler 3 includes the superheater 18 and the first evaporator 17 _-1.
And the first economizer 16 _-1 , the second evaporator 17 _-2 , and the second economizer
16 _-2 consists exhaust heat recovery boiler 4 is comprised of the evaporator 17 and economizer 16.

FIG. 8 is a configuration diagram of a combined cycle power plant according to an eighth embodiment of the present invention.

The first and second embodiments are non-reheat single pressure type system examples,
While the third to seventh embodiments are non-reheat double pressure system examples, this embodiment is a reheat double pressure system example. A major difference from each of the above embodiments is that a reheater is installed in the exhaust heat recovery boiler 3 and the steam turbine 5 is of a reheat type.

In this embodiment, the exhaust heat recovery boiler 3 includes a superheater 18, a reheater 27, an evaporator 17, and a economizer 16. The exhaust heat recovery boiler 4 includes an evaporator 17 and an economizer. It consists of 16.

Water supply 15 is supplied to the exhaust heat recovery boilers 3 and 4 by a water supply pump 14. The feed water 15 branches at the two exhaust heat recovery boilers 3, 4 inlets and is sent to the respective economizers 16 of the respective exhaust heat recovery boilers 3, 4. The water supplied to the economizer 16 of the exhaust heat recovery boiler 4 is
It is heated by the exhaust gas of the gas turbine 2 to become high-temperature water, which is sent to the evaporator 17 of the boiler 4 and heated by the evaporator 17 to become high-pressure saturated steam. This high-pressure saturated steam is sent to the superheater 18 of the exhaust heat recovery boiler 3 and is heated to become superheated steam, and as the main steam 19, the high-pressure turbine of the steam turbine 5.
Supplied to 29. After driving the high-pressure turbine 29, the main steam 19 becomes low-temperature reheat steam at a relatively low temperature and low-pressure, and is sent to the evaporator 17 outlet of the exhaust heat recovery boiler 3. On the other hand, the feed water sent to the economizer 16 of the exhaust heat recovery boiler 3 becomes high-temperature water in the economizer 16 and is sent to the evaporator 17 of the boiler 3. The pressure level of the evaporator 17 is set in cooperation with the pressure level of the low-temperature reheated steam, and the steam generated by the evaporator 17 and the low-temperature reheated steam 26 join and are sent to the reheater 27. The steam superheated by the reheater 27 becomes high-temperature reheated steam 28 and is supplied to the low-pressure turbine 30 of the steam turbine 5.

FIG. 9 is a configuration diagram of a combined cycle power plant according to a ninth embodiment of the present invention. This embodiment, like the eighth embodiment,
Although this is an example of a reheat compound pressure type system, it is different in that the superheater of the exhaust heat recovery boiler 3 is a secondary superheater 23, and a primary superheater 24 is additionally installed in the exhaust heat recovery boiler 4.

FIG. 10 is a configuration diagram of a combined cycle power plant according to a tenth embodiment of the present invention. This embodiment, like the eighth embodiment,
This is an example of a reheat compound pressure type system, but a low-pressure superheater 25 is additionally installed in the exhaust heat recovery boiler 4, and an evaporator of the exhaust heat recovery boiler 3
The difference is that the saturated steam generated in 17 is heated in the low pressure superheater 25 and then merged with the low temperature reheated steam 26.

FIG. 11 is a configuration diagram of a combined cycle power plant according to an eleventh embodiment of the present invention. This embodiment, like the eighth embodiment,
This is an example of a reheat compound pressure type system.
The pressure level of the evaporator 17 is reversed, and a high pressure evaporator is installed in the exhaust heat recovery boiler 3 and a low pressure evaporator is installed in the exhaust heat recovery boiler 4.

FIG. 12 is a configuration diagram of a combined cycle power plant according to a twelfth embodiment of the present invention. In this embodiment, a low pressure evaporator 25 is added to the exhaust heat recovery boiler 4 of the eleventh embodiment.

FIG. 13 is a configuration diagram of a combined cycle power plant according to a thirteenth embodiment of the present invention. This embodiment is different from the first to twelfth embodiments in that it is a system example of reheat triple pressure. A major difference from each of the above-mentioned embodiments is that it has an evaporator with three different pressure levels.

FIG. 14 is a configuration diagram of a combined cycle power plant according to a fourteenth embodiment of the present invention. This embodiment, like the thirteenth embodiment,
This is an example of a reheat triple pressure system, and the bank configuration in each exhaust heat recovery boiler is different from that of the thirteenth embodiment.

According to each of the above-described embodiments, it is possible to construct a system that can efficiently recover heat even if gas turbines having different exhaust gas conditions coexist, at low cost.

Although the embodiment in which two gas turbines of different types are used as heat sources has been described, the present invention is not limited to two, and can be applied to any plurality of gas turbines. It goes without saying that the heat source is not limited to the gas turbine but may be a heat engine such as a diesel engine.

〔The invention's effect〕

According to the present invention, the temperature of the steam to be supplied to the steam turbine is not limited to the low-temperature exhaust gas and can be selected according to the high-temperature exhaust gas, and the steam temperature can be increased, so that the plant thermal efficiency can be improved.

Further, according to the present invention, even in a combined cycle power plant that uses different types of gas turbines, the thermal efficiency of the steam cycle does not decrease due to the gas turbine with a low exhaust gas temperature. The range of selection can be expanded.

[Brief description of the drawings]

Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, Figure 6, Figure 7, Figure 8, Figure 9, Figure 10, Figure 11, Figure 12, and Figure 13.
Figures 14 and 15 respectively show the first, second, third, fourth, fifth, sixth and sixth aspects of the present invention.
7, 8th, 9th, 10th, 11th, 12th, 13th, 14th Embodiment is a block diagram of a combined cycle power plant, and FIG. 15 is a block diagram of a conventional combined cycle power plant. 1, 2 ... Gas turbine, 3, 4 ... Exhaust heat recovery boiler, 5 ... Steam turbine, 6 ... Air, 7 ... Compressor, 8 ... Combustor, 9 ... Fuel, 10 ... Gas turbine section, 11, 21 ... Power generation Machine, 12, 13 ... Exhaust gas, 14 ... Water pump, 15 ... Water supply, 16 ... Economizer, 17 ... Evaporator, 18, 23, 24, 25 ... Superheater, 19 ... Main steam, 20 ... Condenser, 2
7 ... Reheater, 29 ... High pressure turbine.

Front Page Continuation (72) Inventor Eiji Yauchi 3-2-1, Saiwaicho, Hitachi, Ibaraki Hitachi Engineering Co., Ltd. (72) Inventor Yoshiki Noguchi 3-1-1, Saiwaicho, Hitachi, Ibaraki Hitachi, Ltd. Factory Hitachi Factory

Claims (11)

(57) [Claims] 1. A plurality of heat sources having different exhaust heat conditions, a plurality of exhaust heat recovery boilers provided for the respective heat sources and having different bank configurations, and one unit driven by steam generated in each exhaust heat recovery boiler. In the combined power generation plant including the steam turbine, the plurality of exhaust heat recovery boilers constitute one cycle, and the steam turbine is provided at the most upstream part of the exhaust heat recovery boiler into which the hottest exhaust heat flows. A combined cycle power plant comprising a superheater for heating steam to be supplied to. 2. A gas turbine having a plurality of different exhaust heat conditions,
A combined power generation plant including an exhaust heat recovery boiler having a different bank configuration provided for each gas turbine and one steam turbine driven by steam generated in each exhaust heat recovery boiler. The steam generated in the exhaust heat recovery boiler that recovers the exhaust heat of the gas turbine is heated by the superheater installed in the most upstream part of the exhaust heat recovery boiler that recovers the exhaust heat of the hottest gas turbine. A combined cycle power plant characterized in that it is configured to use driving steam. 3. A gas turbine having a plurality of exhaust heat conditions different from each other,
Multiple exhaust heat recovery boilers provided for each gas turbine,
A combined cycle power plant comprising one steam turbine driven by steam generated in each exhaust heat recovery boiler,
It is characterized in that the steam generated in each exhaust heat recovery boiler is combined and heated by the superheater provided at the most upstream part of the exhaust heat recovery boiler into which the hottest exhaust heat flows, and then supplied to the steam turbine. Combined power plant. 4. A gas turbine having a plurality of exhaust heat conditions different from each other,
Multiple exhaust heat recovery boilers provided for each gas turbine,
A combined cycle power plant comprising one steam turbine driven by steam generated in each exhaust heat recovery boiler,
The feedwater that has been preheated in each exhaust heat recovery boiler is combined and turned into steam in the exhaust heat recovery boiler on the low temperature side, and this steam is heated by the superheater installed in the exhaust heat recovery boiler on the highest temperature side and used as steam for driving the steam turbine. The combined power generation plant is characterized in that 5. A gas turbine having a plurality of exhaust heat conditions different from each other,
A combined power generation plant comprising a plurality of exhaust heat recovery boilers provided for respective gas turbines and having different bank configurations, and one steam turbine driven by steam generated in each exhaust heat recovery boiler. A combined power generation plant, wherein a steam generator and a superheater are respectively provided in separate exhaust heat recovery boilers, and steam generated in the evaporator is superheated in the superheater to be steam for driving a steam turbine. 6. A gas turbine having a plurality of exhaust heat conditions different from each other,
A combined cycle power plant comprising an exhaust heat recovery boiler provided for each gas turbine and one double pressure steam turbine driven by steam generated in each exhaust heat recovery boiler,
A combined cycle power plant characterized in that steam superheated by a superheater provided at the most upstream part of the hottest exhaust heat recovery boiler is made to flow into the high-pressure part of the steam turbine as main steam. 7. A gas turbine having a plurality of exhaust heat conditions different from each other,
A combined cycle power plant comprising an exhaust heat recovery boiler provided for each gas turbine and one double pressure steam turbine driven by steam generated in each exhaust heat recovery boiler,
A combined cycle power plant comprising a plurality of exhaust heat recovery boilers constituting one cycle, and an evaporator having a different pressure level being provided in the cycle. 8. A gas turbine having a plurality of exhaust heat conditions different from each other,
A combined cycle power plant comprising an exhaust heat recovery boiler provided for each gas turbine and one reheat steam turbine driven by steam generated in each exhaust heat recovery boiler,
A configuration in which one cycle is composed of the plurality of exhaust heat recovery boilers, and steam heated by a superheater provided at the most upstream part of the hottest exhaust heat recovery boiler is supplied as main steam to a high-pressure turbine of a reheat steam turbine. And a reheater that reheats the steam discharged from the high-pressure turbine is provided in any of the exhaust heat recovery boilers. 9. A gas turbine having a plurality of exhaust heat conditions different from each other,
A combined power generation plant comprising: an exhaust heat recovery boiler provided for each gas turbine; and a single reheat compound pressure steam turbine driven by steam generated in each exhaust heat recovery boiler. The exhaust heat recovery boiler constitutes one cycle, and the steam heated by the superheater provided in the most upstream part of the hottest exhaust heat recovery boiler is supplied as the main steam to the high pressure turbine of the reheat compound pressure steam turbine. At the same time, a reheater that reheats the steam discharged from the high-pressure turbine is provided in any of the exhaust heat recovery boilers, and an evaporator having a different pressure level is provided during the cycle. 10. A plurality of gas turbines having different exhaust heat conditions, an exhaust heat recovery boiler having a bank configuration different for each gas turbine, and one unit driven by steam generated in each exhaust heat recovery boiler. A combined cycle power plant including the steam turbine according to claim 1, wherein one cycle is configured with the plurality of exhaust heat recovery boilers. 11. The combined power generation plant according to claim 2, wherein a diesel engine is used instead of any gas turbine.