JP6057803B2 - Gas turbine plant and method of operating gas turbine plant - Google Patents

Description

  The present invention relates to a gas turbine plant including a gas turbine and an exhaust heat recovery boiler that generates steam using heat of exhaust gas from the gas turbine, and an operation method of the gas turbine plant.

  A gas turbine combined plant is composed of a gas turbine, an exhaust heat recovery boiler, a steam turbine, a generator, and the like. The generator is rotated by the gas turbine and exhaust heat is recovered using exhaust gas discharged from the gas turbine. It is a plant that generates main steam in a boiler and obtains power for power generation in a steam turbine.

For example, Patent Document 1 describes a configuration in which fuel is supplied not only to the combustor of the gas turbine but also to the exhaust heat recovery boiler by installing an auxiliary burner upstream of the exhaust heat recovery boiler.
In this gas turbine combined plant, the time to reach the full load time of the plant can be shortened by promoting steam generation in the exhaust heat recovery boiler by the auxiliary burner when the gas turbine is started.

  Moreover, the amount of steam generation can be increased by using an auxiliary combustion burner to inject the fuel into the exhaust gas over the entire area of the flow path inlet of the exhaust heat recovery boiler. When the steam turbine is operated with the generated steam, the output can be increased as compared with the case where the reheating is not performed.

Japanese Patent Laid-Open No. 11-22419

  As described above, the auxiliary combustion burner can be used to increase the output to a bottoming cycle such as a steam turbine. However, since there is much room for improvement in the thermal efficiency of the entire gas turbine combined plant, the entire gas turbine combined plant It is required to increase the thermal efficiency of the.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a gas turbine plant capable of suppressing a decrease in thermal efficiency of the entire plant while maintaining energy output to the bottoming cycle. There is.

In order to achieve the above object, the present invention provides the following means.
A gas turbine plant of the present invention generates a steam by using a combustor that burns fuel to generate combustion gas, a gas turbine having a turbine driven by the combustion gas, and heat of exhaust gas from the gas turbine. An exhaust heat recovery boiler, an auxiliary combustion combustor that injects fuel into a part of the exhaust gas and burns it at the most upstream portion viewed from the exhaust gas of the exhaust heat recovery boiler, and an auxiliary combustion installed downstream of the auxiliary combustion combustor A part of the exhaust gas that passes through the auxiliary combustor and the remaining part of the exhaust gas that does not pass through the auxiliary combustor merge in the exhaust heat recovery boiler. The fluid heated by the auxiliary combustor heat exchanger is steam supplied to the steam turbine, a preheater for preheating at least one of air and fuel supplied to the combustor, and the auxiliary heater to the auxiliary heater. A Department heat exchanger preheating the steam supplying superheated steam line, characterized in that it comprises a.

According to the above configuration, when the same amount of fuel is input, the temperature of the small amount of exhaust gas supplied to the auxiliary combustion unit heat exchanger becomes higher than when fuel is input to all of the exhaust gas.
When the medium to be heated is water, and the auxiliary fuel is added to all exhaust gas as a comparative example, in the gas turbine plant of the present invention, the same amount of fuel as in the comparative example is supplied to the exhaust gas for auxiliary combustion. Therefore, the temperature of a part of the exhaust gas becomes higher than the temperature of the exhaust gas of the comparative example, and the temperature of the steam can be increased as compared with the temperature of the comparative example.
In the comparative example, since the heat contained in the exhaust gas after the auxiliary combustion is not used much for the overheating of the steam, the amount of heat used for the evaporation of water is increased as compared with the present embodiment. Therefore, a large amount of low temperature steam is generated in the comparative example, whereas a small amount of high temperature steam is generated in the present embodiment. In the comparative example, since the steam flow rate is large, the amount of energy released by the condenser is large, whereas in this embodiment, the steam flow rate is small, and thus is discharged by the condenser. Energy is reduced. Therefore, this embodiment can improve thermal efficiency.
On the other hand, when the medium to be heated is air or fuel supplied to the combustor of the gas turbine, the energy of the combustion gas of the gas turbine increases, so that the thermal efficiency of the gas turbine can be increased.
Moreover, it can preheat using steam with high heat conductivity, a density, and a specific heat, and can reduce a preheater in size. Further, when fuel is preheated, the fuel is preheated with steam, so there is no risk of ignition even if the heat transfer tube of the heat exchanger is damaged and fluids inside and outside the heat transfer tube are mixed.

  In the gas turbine plant, it is preferable that a part of the exhaust gas and a remaining part of the exhaust gas are merged on an upstream side of an evaporator provided on the most upstream side in the exhaust heat recovery boiler.

  According to the above configuration, it is possible to suppress a reduction in the amount of steam generated in the evaporator.

  In the gas turbine plant, a flow rate adjusting means for adjusting a flow distribution between the part of the exhaust gas that passes through the auxiliary combustion combustor and the remaining part of the exhaust gas that does not pass through the auxiliary combustion combustor is provided. Is preferred.

  According to the said structure, the suitable flow volume distribution of waste gas can be obtained using a flow volume adjustment means.

  In the gas turbine plant, it is preferable that the flow rate adjusting means is a pressure loss body that serves as a flow resistance of the remaining portion of the exhaust gas that does not pass through the auxiliary combustion combustor.

  According to the above configuration, the flow rate of the exhaust gas that does not pass through the auxiliary combustion combustor is reduced by the pressure loss body. Therefore, a preferable flow rate distribution can be obtained with a relatively simple configuration.

  In the gas turbine plant, the flow rate adjusting unit may be a flow rate increasing unit that increases a flow rate of the partial flow of the exhaust gas that passes through the auxiliary combustion combustor.

  According to the said structure, the flow volume of the waste gas which passes an auxiliary combustion combustor can be ensured, and suitable flow volume distribution of waste gas can be obtained.

  The gas turbine plant preferably includes auxiliary combustion fuel adjustment means for adjusting an amount of fuel supplied to the auxiliary combustion combustor.

  According to the said structure, the output according to a demand can be obtained, maintaining the high thermal efficiency of a gas turbine plant.

  In the gas turbine plant, a part of the exhaust gas that passes through the auxiliary combustion combustor and a remaining part of the exhaust gas that does not pass through the auxiliary combustion combustor are separated by a partition wall provided in the exhaust heat recovery boiler. Is preferred.

  According to the said structure, mixing with the waste gas which passes an auxiliary combustion combustor and the waste gas which does not pass an auxiliary combustion combustor can be prevented.

The present invention also provides a combustor that burns fuel to generate combustion gas, a gas turbine having a turbine that is driven by the combustion gas, and exhaust gas that generates steam using heat of exhaust gas from the gas turbine. A method of operating a gas turbine plant having a heat recovery boiler and a steam turbine , wherein the fuel is injected into a part of the exhaust gas for auxiliary combustion at the most upstream portion viewed from the exhaust gas of the exhaust heat recovery boiler. And supplying the heat obtained by the auxiliary combustion to the steam supplied to the steam turbine to superheat, and preheating at least one of air and fuel supplied to the combustor using the superheated steam. And a heat recovery process for recovering heat.

  According to the present invention, the thermal efficiency of a gas turbine plant can be improved.

1 is a system diagram of a gas turbine plant in a first embodiment of the present invention. It is a figure which shows the relationship of each calorie | heat amount and temperature accompanying the flow of waste gas and water. It is a systematic diagram of the gas turbine plant in the modification of 1st embodiment of this invention. It is a systematic diagram of the gas turbine plant in the modification of 1st embodiment of this invention. It is a systematic diagram of the gas turbine plant in 2nd embodiment of this invention. It is a systematic diagram of the gas turbine plant in the modification of 2nd embodiment of this invention. It is a systematic diagram of the gas turbine plant in 3rd embodiment of this invention. It is a systematic diagram of the gas turbine plant in 4th embodiment of this invention. It is a figure which shows an example of a flow volume adjustment means. It is a figure which shows an example of a flow volume adjustment means. It is a figure which shows an example of a flow volume adjustment means. It is a systematic diagram of the gas turbine plant in 5th embodiment of this invention.

  As shown in FIG. 1, the gas turbine plant of the present embodiment generates steam by the heat of the gas turbine 10, the generator 15 that generates power by driving the gas turbine 10, and the exhaust gas EG exhausted from the gas turbine 10. Exhaust heat recovery boiler 110, steam turbines 121a, 121b, 121c driven by steam generated in exhaust heat recovery boiler 110, generator 122 generating electric power by driving of steam turbines 121a, 121b, 121c, and steam turbine 121a are driven. A condenser 123 for returning the steam generated to water, a water supply pump 124 for returning the water in the condenser 123 to the exhaust heat recovery boiler 110, and a chimney 40 for releasing the exhaust gas EG that has passed through the exhaust heat recovery boiler 110 to the atmosphere. And.

The gas turbine 10 includes a compressor 11 that compresses air NA, and a plurality of combustions that generate combustion gas by burning the fuel F supplied via the fuel flow path 29 in the air A compressed by the compressor 11. And a turbine 31 driven by high-temperature and high-pressure combustion gas. The turbine rotor of the turbine 31 and the compressor rotor of the compressor 11 rotate about the same axis, and are connected to each other to form a gas turbine rotor. The rotor of the generator 15 is connected to this gas turbine rotor.
The outlet of the compressor 11 and the combustor 21 are connected by a compressed air flow path 12, and the compressed air A compressed by the compressor 11 is supplied to the combustor 21 through the compressed air flow path 12.

The steam turbines 121a, 121b, and 121c include a low-pressure steam turbine 121a, an intermediate-pressure steam turbine 121b (second steam turbine), and a high-pressure steam turbine 121c (first steam turbine).
Further, the exhaust heat recovery boiler 110 includes a low-pressure steam generator 111a that generates low-pressure steam LS, an intermediate-pressure steam generator 111b that generates intermediate-pressure steam IS, and a high-pressure steam that generates high-pressure steam HS (first steam). The generating unit 111c, the reheating unit 115 that reheats the steam that has driven the high-pressure steam turbine 121c, the auxiliary combustion combustor 141 that injects the fuel F into a part of the exhaust gas EG, and combusts, and the downstream of the auxiliary combustion combustor 141 And an auxiliary combustion part heat exchanger 142 installed in the. Further, although the exhaust heat recovery boiler 110 is not shown, the amount of fuel supplied to the auxiliary combustion combustor 141 has auxiliary combustion fuel adjusting means.
In addition, although the generator 122 is provided in each steam turbine 121a, 121b, 121c here, it is with respect to a total of three steam turbines, the low pressure steam turbine 121a, the intermediate pressure steam turbine 121b, and the high pressure steam turbine 121c. One generator 122 may be provided.

  The low-pressure steam generator 111a superheats the low-pressure economizer 112a that heats water, the low-pressure evaporator 113a that converts water heated by the low-pressure economizer 112a into steam, and the steam generated by the low-pressure evaporator 113a. And a low-pressure superheater 114a that generates low-pressure steam LS.

  The intermediate pressure steam generator 111b includes an intermediate pressure pump 116b that pressurizes water heated by the low pressure economizer 112a, an intermediate pressure economizer 112b that heats water pressurized by the intermediate pressure pump 116b, An intermediate pressure evaporator 113b that turns water heated by the economizer 112b into steam, and an intermediate pressure superheater 114b that generates the intermediate pressure steam IS (second steam) by superheating the steam generated in the intermediate pressure evaporator 113b. And have.

  The high-pressure steam generator 111c includes a high-pressure pump 116c that pressurizes water heated by the low-pressure economizer 112a, a first high-pressure economizer 112c that heats water pressurized by the high-pressure pump 116c, and a first high-pressure economizer. Generated by the second high-pressure economizer 112d for further heating the water heated by the carbonizer 112c, the high-pressure evaporator 113c for converting the water heated by the second high-pressure economizer 112d into steam, and the high-pressure evaporator 113c The first high-pressure superheater 114c that superheats the steam and the second high-pressure superheater 114d that further superheats the steam superheated by the first high-pressure superheater 114c to generate the high-pressure steam HS.

  The auxiliary combustion combustor 141 is disposed at the most upstream portion viewed from the exhaust gas EG of the exhaust heat recovery boiler 110. The auxiliary combustion part heat exchanger 142 is provided downstream of the auxiliary combustion combustor 141 and further upstream of the second high-pressure superheater 114d and the second reheater 115b. The auxiliary combustion part heat exchanger 142 is connected to the steam outlet of the second high-pressure superheater 114d.

  A partition wall 143 is provided inside the exhaust heat recovery boiler 110. The partition wall 143 has a main surface along the flow direction of the exhaust gas EG (hereinafter simply referred to as the flow direction), and flows so as to divide the cross section perpendicular to the flow direction of the exhaust heat recovery boiler 110 into two sections. Extends in the direction. The range along the flow direction in which the partition wall 143 is installed corresponds to the position where the auxiliary combustion combustor 141 and the auxiliary combustion part heat exchanger 142 are arranged.

The partition wall 143 extends to divide the range in the flow direction in which the auxiliary combustion combustor 141 and the auxiliary combustion part heat exchanger 142 are arranged into two sections, and the auxiliary combustion combustor 141 and the auxiliary combustion part heat exchanger 142. Are arranged in one of these sections.
That is, the partition wall 143 is disposed so that the exhaust gas EG introduced into the exhaust heat recovery boiler 110 flows separately in the exhaust heat recovery boiler 110 on one side and the other side of the partition wall 143.

  The reheat unit 115 generates a reheat steam RHS by further superheating the steam reheated by the first reheater 115a that heats the steam that has driven the high-pressure steam turbine 121c and the first reheater 115a. Two reheaters 115b.

  The elements constituting the exhaust heat recovery boiler 110 are the auxiliary combustion combustor 141, the auxiliary combustion part heat exchanger 142, the second reheater 115b, and the second high-pressure overheat toward the downstream side of the exhaust gas EG from the turbine 31 toward the chimney 40. 114d, first reheater 115a, first high pressure superheater 114c, high pressure evaporator 113c, second high pressure economizer 112d, medium pressure superheater 114b and low pressure superheater 114a, medium pressure evaporator 113b, first high pressure The economizer 112c, the medium-pressure economizer 112b, the low-pressure evaporator 113a, and the low-pressure economizer 112a are arranged in this order.

The condenser 123 and the low pressure economizer 112 a are connected by a water supply line 131. The water supply line 131 is provided with the above-described water supply pump 124.
The low pressure superheater 114a and the steam inlet of the low pressure steam turbine 121a are connected by a low pressure steam line 132 that sends the low pressure steam LS from the low pressure superheater 114a to the low pressure steam turbine 121a.

The steam outlet of the low-pressure steam turbine 121 a and the condenser 123 are connected to each other so that the low-pressure steam LS that drives the low-pressure steam turbine 121 a is supplied to the condenser 123. The auxiliary combustor heat exchanger 142 and the steam inlet of the high-pressure steam turbine 121c are connected by a high-pressure steam line 138 that sends the high-pressure steam HS to the high-pressure steam turbine 121c.
The steam outlet of the high-pressure steam turbine 121c and the steam inlet of the first reheater 115a are connected by a high-pressure steam recovery line 139 that sends the high-pressure steam HS from the high-pressure steam turbine 121c to the first reheater 115a.

  The steam outlet of the second reheater 115b and the steam inlet of the intermediate pressure steam turbine 121b are a reheat steam line 136 that sends the steam superheated by the second reheater 115b to the intermediate pressure steam turbine 121b as reheated steam RHS. Connected with. An intermediate pressure steam recovery line 137 is connected to the steam outlet of the intermediate pressure steam turbine 121b. The intermediate pressure steam recovery line 137 merges with the low pressure steam line 132. An intermediate pressure steam line 133 is connected to the steam outlet of the intermediate pressure superheater 114b. The intermediate pressure steam line 133 joins the high pressure steam recovery line 139.

Next, operation | movement of the combined plant of this embodiment demonstrated above is demonstrated.
The compressor 11 of the gas turbine 10 compresses air NA in the atmosphere and supplies the compressed air A to the combustor 21 via the compressed air flow path 12. Further, the fuel F from the fuel flow path 29 is also supplied to the combustor 21. In the combustor 21, the fuel F is combusted in the compressed air A, and high-temperature and high-pressure combustion gas is generated. The combustion gas is sent to the turbine 31 and rotates the turbine rotor of the turbine 31. The generator 15 connected to the gas turbine 10 generates power by the rotation of the turbine rotor.

  The combustion gas obtained by rotating the turbine rotor of the turbine 31 is exhausted from the gas turbine 10 as exhaust gas EG, and is discharged from the chimney 40 to the atmosphere via the exhaust heat recovery boiler 110. The exhaust heat recovery boiler 110 recovers heat contained in the exhaust gas EG in the process of passing the exhaust gas EG from the gas turbine 10.

The exhaust gas EG flowing into the exhaust heat recovery boiler 110 is separated by the partition wall 143 into the auxiliary combustor 141 side and the gap S side. That is, a part of the exhaust gas EG flows into the auxiliary combustor 141 side, and the remaining part of the exhaust gas EG flows into the gap S.
On the other hand, the fuel F is supplied to the auxiliary combustion combustor 141 through the second fuel flow path 29b. The amount of fuel is adjusted by the auxiliary fuel adjusting means. Thereby, the auxiliary combustion is performed by the auxiliary combustion combustor 141, and the temperature of the exhaust gas EG on the downstream side of the auxiliary combustion combustor 141 is increased.

  The exhaust gas EG separated by the partition wall 143 joins on the downstream side of the partition wall 143. That is, the exhaust gas EG joins on the upstream side of the second reheater 115b and the second high pressure superheater 114d, and further flows downstream. Since the second reheater 115b and the second high pressure superheater 114d are provided on the upstream side of the high pressure evaporator 113c, which is an evaporator provided on the most upstream side, the exhaust gas EG is supplied to the exhaust heat recovery boiler. 110 joins upstream of the evaporator provided on the most upstream side of 110.

The evaporator may be a subcritical pressure boiler, that is, a natural circulation boiler, a forced circulation boiler, a once-through boiler, or the like. Moreover, it includes not only evaporation in a once-through boiler, but also heating up to the saturation temperature of water and the generated steam including overheating.
In addition, it includes a supercritical pressure boiler (a device that heats supercritical water whose temperature is lower than the pseudocritical temperature above the pseudocritical temperature, where the pseudocritical temperature is the temperature at which the constant pressure specific heat is maximized). Shall be.

  In the exhaust heat recovery boiler 110, water from the condenser 123 is supplied to the low-pressure economizer 112a on the most downstream side (chimney 40 side) via the water supply line 131. The low pressure economizer 112a heats this water by exchanging heat with the exhaust gas EG. A part of the water heated by the low pressure economizer 112a is further heated by the low pressure evaporator 113a to become steam. This steam is further heated by the low-pressure superheater 114a and supplied as low-pressure steam LS to the low-pressure steam turbine 121a via the low-pressure steam line 132. The steam that has driven the low-pressure steam turbine 121 a returns to water in the condenser 123. This water is supplied again from the condenser 123 to the low-pressure economizer 112 a through the water supply line 131.

  The other part of the water heated by the low pressure economizer 112a is pressurized by the intermediate pressure pump 116b and sent to the intermediate pressure economizer 112b, and the remaining water heated by the low pressure economizer 112a is high pressure. The pressure is raised by the pump 116c and sent to the first high-pressure economizer 112c.

The first high-pressure economizer 112c heats the water sent from the high-pressure pump 116c by exchanging heat with the exhaust gas EG. The water heated by the first high pressure economizer 112c is further heated by the second high pressure economizer 112d. This water is further heated by the high-pressure evaporator 113c to become steam. This steam is further superheated by the first high-pressure superheater 114c and the second high-pressure superheater 114d.
This steam is further superheated by the auxiliary combustor heat exchanger 142 to become high-pressure steam HS. The high-pressure steam HS is supplied to the high-pressure steam turbine 121c via the high-pressure steam line 138.

The intermediate pressure economizer 112b heats the water sent from the intermediate pressure pump 116b by exchanging heat with the exhaust gas EG. The water heated by the medium pressure economizer 112b is further heated by the intermediate pressure evaporator 113b to become steam. This steam is further superheated by the medium pressure superheater 114b to become medium pressure steam IS. This intermediate pressure steam IS joins with the steam flowing through the high pressure steam recovery line 139 via the intermediate pressure steam line 133, is reheated by the first reheater 115a and the second reheater 115b, and reheated steam RHS. It becomes. The reheat steam RHS is supplied to the intermediate pressure steam turbine 121b via the reheat steam line 136.
The reheated steam RHS that has driven the intermediate pressure steam turbine 121b is supplied to the low pressure steam turbine 121a via the intermediate pressure steam recovery line 137 and the low pressure steam line 132.

According to the above embodiment, the thermal efficiency of the gas turbine plant can be improved by supporting only a part of the exhaust gas.
The principle will be described below.
FIGS. 2A and 2B show the relationship between the amount of heat and temperature (TQ diagram) associated with the flow of exhaust gas and water (steam). In FIG. 2, the vertical axis represents temperature, and the horizontal axis represents heat quantity. FIG. 2A is a TQ diagram in the case where auxiliary combustion fuel is introduced into all exhaust gas EG (hereinafter referred to as a comparative example). FIG. 2B is a TQ diagram in the case of the present embodiment in which auxiliary combustion fuel is introduced into a part of the exhaust gas EG. FIG. 2C is a diagram in which the overlapping portions are illustrated in white after overlapping FIG. 2A and FIG.
In the comparative example and the present embodiment, the same amount of fuel is used. The amount of heat contained in the exhaust gas after the auxiliary combustion is also the same.

The exhaust gas flows in the order of superheater, evaporator, and economizer. The amount of heat of the exhaust gas is lowered by applying heat to water (steam) in this process.
On the other hand, the water is preheated in the economizer as it goes from right to left in FIG.

  In the gas turbine plant of the present embodiment, the same amount of fuel as that in the comparative example is supplied to assist combustion in a part of the exhaust gas, so that the temperature of a part of the exhaust gas is the temperature of the exhaust gas in the comparative example (reference numeral in FIG. Compared with F), the temperature becomes higher (reference G in FIG. 2C). Therefore, the temperature of the steam obtained by the superheater can also be made higher than the temperature of the comparative example (symbol D in FIG. 2C) (symbol E in FIG. 2C).

In the comparative example, since the same amount of fuel as in the present embodiment is input to the entire exhaust gas, the temperature of the exhaust gas does not rise more than in the present embodiment. That is, in the comparative example, the heat contained in the exhaust gas after the auxiliary combustion is not often used for steam overheating.
However, the amount of heat contained in the exhaust gas after combustion is the same in this embodiment and the comparative example. For this reason, the amount of heat used for the evaporation of water is larger in the comparative example than in the present embodiment.
As a result, the amount of steam generated in the comparative example is larger than that in the present embodiment. Therefore, a large amount of low temperature steam is generated in the comparative example, whereas a small amount of high temperature steam is generated in the present embodiment.

  In this embodiment and the comparative example, the energy of the steam flowing into the steam turbine is almost the same. By the way, in the condenser which returns the steam from the steam turbine to water, the energy of the steam is released to the outside. In the comparative example, the amount of energy released is large because of a large amount of steam flow. In this embodiment, since the steam flow rate is small, the released energy is small. Therefore, this embodiment can improve thermal efficiency. That is, it is more efficient to supply a small amount of high-temperature steam to the steam turbine than to supply a large amount of low-temperature steam to the steam turbine.

  Here, in order to effectively use the heat contained in the exhaust gas after the auxiliary combustion, it is necessary to reduce the temperature difference between the exhaust gas and water (steam). The smaller the area shown by hatching in FIGS. 2 (a) and 2 (b), the more effective heat utilization is.

In the gas turbine plant of the present embodiment, only a part of the exhaust gas is combusted. Therefore, the heat capacity of the exhaust gas in this part is small, and the temperature drop is large with respect to the equivalent heat exchange amount. Thus, the negative slope becomes large. As a result, the temperature difference of (exhaust gas-steam) in the superheater is reduced, and the area of the hatched portion is reduced.
That is, in FIG. 2C, which compares the comparative example and this embodiment, the area of the B + C portion is smaller than the area of the A portion, and heat can be used effectively.

  In addition, since the partition wall 143 is formed so that the exhaust gas EG joins upstream of the high-pressure evaporator 113c, the exhaust gas EG after joining the evaporator flows, so the amount of heat given by the exhaust gas EG The temperature drop of the exhaust gas EG is reduced. Thereby, although this embodiment reduces evaporation amount compared with a comparative example, the fall can be suppressed to the minimum.

  If the exhaust gas merger is further downstream than the evaporator, the flow rate of the exhaust gas passing through the evaporator is small, and the temperature drop is abrupt. In order to perform heat exchange, the temperature of the exhaust gas must always be higher than the temperature of water, so the amount of water must be reduced and the amount of steam generated is reduced.

  Further, by providing the partition wall 143, mixing of the exhaust gas EG passing through the auxiliary combustion combustor 141 and the exhaust gas EG not passing through the auxiliary combustion combustor 141 can be prevented.

  In addition, since the medium heated by the auxiliary combustor heat exchanger 142 is steam, the temperature difference between the exhaust gas EG and the steam in the auxiliary combustor heat exchanger 142 can be reduced and heat can be efficiently recovered.

(Modification 1)
Next, a modification of the gas turbine plant of the first embodiment will be described.
As shown in FIG. 3, in the gas turbine plant of the first modification, the auxiliary combustion part heat exchanger 142 is connected to the steam outlet of the second reheater 115b, and the auxiliary combustion combustor 141 is the steam of the second reheater 115b. It arrange | positions so that the waste gas EG used for heat exchange of the auxiliary combustion part heat exchanger 142 connected to the exit may be heated up.
That is, the auxiliary combustion part heat exchanger 142 of the present embodiment is configured to overheat the intermediate pressure steam IS. In other words, the steam superheated by the auxiliary combustor heat exchanger 142 is not limited to the high-pressure steam HS.

Whether the auxiliary combustor heat exchanger 142 superheats the intermediate-pressure steam IS or the high-pressure steam HS can be selected as appropriate according to the specifications of the plant and the required temperature.
In addition, in the structure which the auxiliary combustion part heat exchanger 142 overheats the intermediate pressure steam IS like this modification, compared with the case where the high pressure steam HS is overheated, the auxiliary temperature heat exchanger has the highest temperature as the steam. The pressure of the steam superheated at 142 is low, the stress of the heat transfer pipe of the auxiliary combustion section heat exchanger 142 and the pipe transporting the superheated steam at the auxiliary combustion section heat exchanger can be reduced, and the condition of the creep strength can be relaxed. it can.

(Modification 2)
Next, another modification of the gas turbine plant of the first embodiment will be described.
As shown in FIG. 4, the auxiliary combustion combustor 141 and the auxiliary combustion part heat exchanger 142 of the gas turbine plant of the present embodiment are housed in a casing 145 that is independent from the casing of the exhaust heat recovery boiler 110. It is said. The casing of the exhaust heat recovery boiler 110 and the casing 145 are connected by an exhaust gas pipe 146 that introduces the exhaust gas EG used by the auxiliary heat exchanger 142 into the casing of the exhaust heat recovery boiler 110.

  According to the modified example, the exhaust gas EG can be separated without providing the partition wall 143 (see FIG. 1). Moreover, the introduction to the existing exhaust heat recovery boiler 110 becomes easy.

(Second embodiment)
As shown in FIG. 5, the gas turbine plant of the present embodiment is characterized in that the compressed air A supplied from the compressor 11 is preheated by using an auxiliary combustor heat exchanger 142. That is, the fluid heated by the auxiliary combustor heat exchanger 142 is not limited to steam.

  Specifically, the compressed air flow path 12 is connected to both ends of the heat transfer tube of the auxiliary combustor heat exchanger 142. In other words, the auxiliary combustion part heat exchanger 142 is disposed on the compressed air flow path 12. Thereby, the compressed air A is preheated by the auxiliary combustion part heat exchanger 142 that recovers the heat obtained by the auxiliary combustion of the auxiliary combustion combustor 141.

According to the said embodiment, the thermal efficiency of the bottoming cycle using the gas turbine 10 or waste heat can be improved by preheating the compressed air A.
Moreover, since the heat obtained by the auxiliary combustor heat exchanger 142 can be more efficiently given to the compressed air A, the thermal efficiency of the bottoming cycle using the gas turbine or exhaust heat can be further increased.

(Modification 3)
Next, a modification of the gas turbine plant of the second embodiment will be described.
As shown in FIG. 6, the gas turbine plant according to the present modification is characterized in that fuel F supplied to the combustor 21 is preheated using an auxiliary combustor heat exchanger 142.

  Specifically, the fuel flow path 29 is connected to both ends of the heat transfer tube of the auxiliary combustor heat exchanger 142. In other words, the auxiliary combustor heat exchanger 142 is disposed on the fuel flow path 29. As a result, the fuel F is preheated by the auxiliary combustion part heat exchanger 142 that recovers the heat obtained by the auxiliary combustion of the auxiliary combustion combustor 141.

According to the above embodiment, the fuel F is preheated, so that the thermal efficiency of the bottoming cycle using the gas turbine 10 and the exhaust heat can be increased.
For example, if the fuel flow rate is constant before and after preheating, the amount of heat brought into the combustor 21 by preheating increases, the turbine inlet temperature (of the gas turbine 10) rises, and the exhaust gas temperature rises (if the pressure ratio is constant), Since the steam temperature can be increased, the efficiency of the bottoming cycle is also increased.
Further, when the turbine inlet temperature (of the gas turbine 10) is made constant, the amount of heat of the unit mass of fuel increases due to preheating, and the fuel required to obtain an equivalent turbine inlet temperature decreases. The denominator of thermal efficiency becomes smaller, and the efficiency of both gas turbine / bottoming increases.

  Moreover, since the heat obtained by the auxiliary combustor heat exchanger 142 can be more efficiently given to the fuel F, the thermal efficiency of the bottoming cycle using the gas turbine or exhaust heat can be further increased.

(Third embodiment)
As shown in FIG. 7, the gas turbine plant according to the present embodiment is characterized in that the compressed air A and the fuel F are preheated using the steam superheated by the auxiliary combustion part heat exchanger 142.
Specifically, the steam superheated by the auxiliary combustor heat exchanger 142 is installed on the compressed air passage 12 and the fuel passage 29 via the preheating steam line 147 and functions as a preheater. The heat transfer tubes 51 and 52 are introduced. The steam used in the heat exchangers 51 and 52 is reheated by the second reheater 115b via the preheated steam recovery line 148 and then supplied to the intermediate pressure steam turbine 121b.

  According to the said embodiment, it can preheat using steam with high heat conductivity, a density, and a specific heat, and can reduce the heat exchangers 51 and 52 in size. Further, when the fuel F is preheated, the fuel F is preheated with steam, so that there is no risk of ignition even if the heat transfer tubes of the heat exchangers 51 and 52 are damaged and fluids inside and outside the heat transfer tubes are mixed.

  In addition, in the said embodiment, although the structure which preheats both the compressed air A and the fuel F using the two heat exchangers 51 and 52 was shown, it is not necessary to preheat both the compressed air A and the fuel F. Absent.

(Fourth embodiment)
As shown in FIG. 8, in the gas turbine plant of the present embodiment, the gap formed on the other side of the partition wall 143 opposite to the one side where the auxiliary combustion combustor 141 and the auxiliary combustion part heat exchanger 142 are arranged. S is characterized in that a flow rate adjusting means 60 is provided. The flow rate adjusting means 60 is a means for adjusting the flow distribution of the exhaust gas EG that passes through the auxiliary combustion combustor 141 and the exhaust gas EG that does not pass through the auxiliary combustion combustor 141.

  The flow rate adjusting means 60 is a pressure loss body that becomes a resistance of the exhaust gas EG and a pressure loss (pressure loss) of the exhaust gas EG. As shown in FIG. 9, the flow rate adjusting means 60 is configured by a tube group 61 composed of a plurality of circular tubes similar to the heat exchanger. Since the purpose of the tube group 61 is to cause a pressure loss, no fluid is flowed.

The form of the flow rate adjusting means 60 is not limited to the tube group 61, and as shown in FIG. 10 (a) and FIG. 10 (b) which is an A arrow view of FIG. A wire mesh 62 arranged in a grid pattern may be provided.
Alternatively, as shown in FIG. 11, a damper 63 may be provided. The damper 63 has a pair of damper main bodies 64 and a rotating shaft 65 that rotatably holds the damper main body 64, and is configured to be able to adjust the flow rate of the exhaust gas EG.

  According to the above embodiment, the flow rate adjusting means 60 adjusts the flow rate distribution of the exhaust gas EG that passes through the auxiliary combustion combustor 141 and the exhaust gas EG that does not pass through the auxiliary combustion combustor 141, so that a suitable flow rate distribution can be obtained. .

(Fifth embodiment)
As shown in FIG. 12, the flow rate adjusting means of the present embodiment is a pressure increasing means 67 that is provided in the flow path of the exhaust gas EG passing through the auxiliary combustion combustor 141 and functions as a flow rate increasing means. That is, the flow rate adjusting means 60 is a pressure increasing means 67 that recovers the pressure lost by the auxiliary combustion portion heat exchanger 142 of the exhaust gas EG.
Specifically, the pressurizing unit 67 can be configured by a fan, a blower, or the like that increases the flow rate of the circulating fluid.

  According to the above embodiment, the flow rate of the exhaust gas EG passing through the auxiliary combustor 141 can be ensured, and a suitable flow rate distribution of the exhaust gas EG can be obtained.

  The technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. In other words, the configuration described in the above-described embodiment is an example, and can be appropriately changed.

DESCRIPTION OF SYMBOLS 10 Gas turbine 11 Compressor 12 Compressed air flow path 15 Generator 21 Combustor 29 Fuel flow path 29b Second fuel flow path 31 Turbine 51, 52 Heat exchanger (preheater)
40 Chimney 60 Flow rate adjusting means 67 Pressure increasing means (flow rate increasing means)
DESCRIPTION OF SYMBOLS 100 Waste heat recovery apparatus 111a Low pressure steam generation part 111b Medium pressure steam generation part 111c High pressure steam generation part 112a Low pressure economizer 112b Medium pressure economizer 112c First high pressure economizer 112d Second high pressure economizer 113a Low pressure evaporator 113b Medium pressure evaporator 113c High pressure evaporator 114a Low pressure superheater 114b Medium pressure superheater 114c First high pressure superheater 114d Second high pressure superheater 115 Reheating part 115a First reheater 115b Second reheater 116b Medium pressure pump 116c High-pressure pump 121a Low-pressure steam turbine (steam turbine)
121b Medium-pressure steam turbine (second steam turbine)
121c High-pressure steam turbine (first steam turbine)
122 generator 123 condenser 124 feed water pump 131 feed water line 132 low pressure steam line 133 medium pressure steam line 136 reheat steam line 137 medium pressure steam recovery line 138 high pressure steam line 139 high pressure steam recovery line 141 auxiliary combustion combustor 142 heat of auxiliary combustion section Exchanger 143 Partition wall 145 Casing 146 Exhaust gas pipe 147 Preheating steam line 148 Preheating steam recovery line A Compressed air EG Exhaust gas F Fuel LS Low pressure steam IS Medium pressure steam (second steam)
HS High-pressure steam (first steam)
S gap

Claims (8)

A combustor for combusting fuel to generate combustion gas, and a gas turbine having a turbine driven by the combustion gas;
An exhaust heat recovery boiler that generates steam using the heat of the exhaust gas from the gas turbine;
An auxiliary combustion combustor that injects fuel into a part of the exhaust gas and burns it at the most upstream portion as viewed from the exhaust gas of the exhaust heat recovery boiler;
An auxiliary heat exchanger installed downstream of the auxiliary combustor;
A steam turbine ,
A part of the exhaust gas that passes through the auxiliary combustion combustor and a remaining part of the exhaust gas that does not pass through the auxiliary combustion combustor merge inside the exhaust heat recovery boiler ,
The fluid heated by the auxiliary combustor heat exchanger is steam supplied to the steam turbine,
A preheater for preheating at least one of air and fuel supplied to the combustor;
A gas turbine plant , comprising: a preheating steam line that supplies the preheater with steam superheated by the auxiliary combustion part heat exchanger .   2. The exhaust gas recovery apparatus according to claim 1, wherein a part of the exhaust gas and a remaining part of the exhaust gas merge upstream of an evaporator provided on the most upstream side in the exhaust heat recovery boiler. Gas turbine plant. The flow rate adjusting means for adjusting the flow distribution between the part of the exhaust gas that passes through the auxiliary combustion combustor and the remaining part of the exhaust gas that does not pass through the auxiliary combustion combustor is provided. The gas turbine plant according to claim 1 or 2 . 4. The gas turbine plant according to claim 3 , wherein the flow rate adjusting means is a pressure loss body that becomes a resistance of a flow of the remaining portion of the exhaust gas that does not pass through the auxiliary combustion combustor. 4. The gas turbine plant according to claim 3 , wherein the flow rate adjusting unit is a flow rate increasing unit that increases a flow rate of the partial flow of the exhaust gas that passes through the auxiliary combustion combustor. The gas turbine plant according to any one of claims 1 to 5 , further comprising auxiliary combustion fuel adjustment means for adjusting an input amount of fuel supplied to the auxiliary combustion combustor. The part of the exhaust gas that passes through the auxiliary combustion combustor and the remaining part of the exhaust gas that does not pass through the auxiliary combustion combustor are separated by a partition wall provided in the exhaust heat recovery boiler. The gas turbine plant according to any one of claims 1 to 6 . A combustor for combusting fuel to generate combustion gas; a gas turbine having a turbine driven by the combustion gas; an exhaust heat recovery boiler for generating steam using heat of exhaust gas from the gas turbine; and steam a method of operating a gas turbine plant with a turbine, a,
In the most upstream part as viewed from the exhaust gas of the exhaust heat recovery boiler, a step of adding the fuel to a part of the exhaust gas to assist combustion,
The heat obtained by the auxiliary combustion is supplied to the steam supplied to the steam turbine to superheat, and the superheated steam is used to preheat at least one of air and fuel supplied to the combustor. A heat recovery process to recover;
A method for operating a gas turbine plant, comprising:

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