JP2004211654A - Gas turbine plant and combined plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve thermal efficiency by using heat provided by cooling a gas turbine high temperature part for heating introductory air to a burner and fuel. <P>SOLUTION: A gas turbine plant P is provided with a gas turbine 10 and a closed loop circulation system 100 cooling the gas turbine high temperature part (a moving blade 13A, a stationary blade 13B). The closed loop circulation system 100 circulates steam as a medium, and is provided with heat exchangers 42A, 42B arranged in the gas turbine high temperature part, a heat exchanger 102 arranged in an air introductory passage from a compressor 11 to the burner 12, a condenser 104 condensing steam after passing the heat exchanger 102, a pump 106 forcingly circulating water after condensation, and a heater 108 heating water sent out by the pump 106 to generate steam in a circulation route, temperature of fuel and air introduced to the burner 12 is raised by heat provided by cooling the gas turbine high temperature part. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gas turbine plant and a combined plant provided with a cooling mechanism for a gas turbine high-temperature section.
[0002]
[Prior art]
In order to increase the efficiency of gas turbines, the turbine inlet temperature of combustion gas has been increasing year by year, and recently, an H-type gas turbine in which the temperature is set at a level of 1500 ° C. has been developed.
In a conventional gas turbine plant, it is common to cool a high-temperature portion of a gas turbine system, such as a stationary blade, a moving blade, and a combustor, of a gas turbine system by supplying air extracted from a compressor. (See Patent Document 1 below).
[0003]
However, as described above, as the turbine inlet temperature increases, it is required to further improve the cooling performance of the turbine components, and in order to realize this, instead of the conventional air cooling, steam is used. Development of a steam-cooled gas turbine for cooling is underway.
The steam cooling system has been widely studied as an effective cooling system for gas turbines, instead of the air cooling system, as a number of combined plants have been constructed in response to the high temperature and high efficiency of power plants in recent years. ing.
[0004]
In particular, in a combined plant, a part of steam generated in a steam turbine system as a bottoming cycle is extracted and guided to a gas turbine, and the steam whose temperature has increased after cooling the gas turbine is recovered and returned to the steam turbine side again. As a result, steam can be effectively used. Accordingly, steam-cooled gas turbines have recently attracted attention as contributing to the efficiency of power plants (see Patent Documents 2 and 3 below).
[0005]
FIG. 2 is a conceptual diagram showing a general example in which a steam-cooled gas turbine is used in a combined plant. This combined plant includes a gas turbine 10, an exhaust heat recovery boiler 20, and a steam turbine 30.
[0006]
The gas turbine 10 includes a compressor 11 that compresses air, a combustor 12 that burns fuel together with air discharged from the compressor 11, and a turbine that expands high-temperature combustion gas from the combustor 12 to turn a generator 15. The generator 15 generates electric power obtained by subtracting the drive output of the compressor 11. The combustion gas exhausted from the gas turbine 10 is supplied to the exhaust heat recovery boiler 20, where the boiler 20 generates steam with the high-temperature combustion gas from the gas turbine 10, and the exhaust gas is discharged from the chimney 25 to the atmosphere. The generated steam is supplied to the high-pressure steam turbine 30A and the medium- and low-pressure steam turbine 30B according to the temperature and pressure conditions, and turns the generator 100 to generate electric power. The outlet steam of the middle and low pressure steam turbine 30 </ b> B is converted from steam into water by the condenser 32, and the water is pressurized by the feedwater pump 33 and returned to the exhaust heat recovery boiler 20.
[0007]
In this plant, a part of the outlet steam of the high-pressure steam turbine 30A is extracted for cooling the high-temperature portions (turbine rotor blades 13A, turbine stationary blades 13B) of the gas turbine 10 and cooled through a cooling steam supply pipe 41. The steam is supplied to the heat exchangers 42A and 42B for cooling the turbine blades, and the steam whose temperature has been increased by cooling is returned to the boiler 20 from the cooling steam recovery pipe 43.
[0008]
[Patent Document 1]
JP 10-196316 A [Patent Document 2]
JP 2002-54405 A [Patent Document 3]
JP 2001-98902 A
[Problems to be solved by the invention]
By the way, in a plant employing a conventional air-cooled gas turbine, the high temperature portion of the gas turbine is cooled by supplying air extracted from the compressor.However, since cooling is performed by air, combustion air is reduced, and thermal efficiency is reduced. There was a problem that contribution to improvement was low.
[0010]
In addition, plants that use a conventional steam-cooled gas turbine use steam as a refrigerant, which improves cooling efficiency and improves the efficiency of returning the heated steam after cooling the gas turbine to the bottoming cycle again. Although good results can be achieved in the point of the above, the operating temperature range between the gas turbine cycle (Brayton cycle) having an operating temperature range of 600 to 1500 ° C. and the bottoming cycle (Rankin cycle) having an operating temperature range of 600 ° C. or less is Since heat transfer is performed between two greatly different cycles, heat loss is likely to occur, and there is still room for improvement in terms of improving thermal efficiency.
[0011]
The present invention has been made in view of the above circumstances, and aims to further improve thermal efficiency by utilizing heat obtained in a high-temperature side cycle (Brayton cycle forming a gas turbine) in a high-temperature side cycle. It is an object of the present invention to provide a gas turbine plant and a combined plant that can be operated.
[0012]
[Means for Solving the Problems]
The gas turbine plant according to claim 1, wherein a compressor for compressing air, a combustor for burning fuel together with air discharged from the compressor, and a mechanical output for expanding hot combustion gas from the combustor. And a first heat exchanger disposed in a high temperature part of the gas turbine, and at least one of an air introduction passage from the compressor to the combustor and a fuel introduction passage to the combustor. A closed-loop circulation system that circulates a medium between the second heat exchanger and an air or a fuel introduced into the combustor with heat obtained by cooling a high-temperature portion of the gas turbine. And characterized in that:
[0013]
In the gas turbine plant of the present invention, the cooling system of the gas turbine high-temperature section is configured by a closed-loop circulating system. For example, by employing steam as a medium, the gas turbine is cooled by a steam cooling system. Can be. In addition, since the heat obtained by cooling the high temperature portion of the gas turbine is used for raising the temperature of the introduced air and the introduced fuel to the combustor via the second heat exchanger, the cycle in which the operating temperature range differs significantly. Heat transfer between the two can be eliminated, and heat loss due to heat transfer can be reduced. For example, even when steam is used as a refrigerant, there is no need to bring steam for cooling the high temperature portion of the gas turbine from the bottoming cycle, so that the gas turbine cycle (Brayton cycle) and the bottoming cycle (Rankine cycle) whose operating temperature ranges are significantly different from each other. ) Can be eliminated, and heat loss can be reduced. In addition, the temperature of the air introduced into the combustor and the temperature of the introduced fuel can be increased by using the medium that has become hot due to cooling, so the amount of heat input to the combustor can be reduced and the thermal efficiency of the gas turbine can be improved. It can greatly contribute.
[0014]
The gas turbine plant according to claim 2 is the gas turbine plant according to claim 1, wherein the medium circulated through the closed loop circulation system is steam, and the steam is forced into the closed loop circulation system for forced circulation of the steam. An air supply device is provided.
[0015]
In the gas turbine plant of the present invention, steam as a medium is forcibly circulated in the closed loop circulation system by the air supply device, so that an efficient steam-cooled gas turbine cycle is provided without receiving supply of steam from the bottoming cycle. Can be made.
[0016]
According to a third aspect of the present invention, in the gas turbine plant of the second aspect, an auxiliary boiler for supplying steam into the closed loop circulation system at the time of starting the plant is provided.
[0017]
In the gas turbine plant of the present invention, since steam in the initial stage of operation can be generated by the auxiliary boiler, an efficient steam-cooled gas turbine cycle can be realized from the beginning of operation.
[0018]
According to a fourth aspect of the present invention, in the gas turbine plant according to the first aspect, the medium circulated in the closed loop circulation system is steam, and after passing through the second heat exchanger in the closed loop circulation system. A condenser for condensing steam, a pump for forcibly circulating water after condensation by the condenser, and a pump interposed between the pump and the first heat exchanger for heating water sent out by the pump. A heater for generating steam is provided.
[0019]
In the gas turbine plant of the present invention, since the steam as the medium is converted into water and circulated by the pump, the equipment can be simplified as compared with the case where the steam is circulated by the air supply device.
[0020]
A combined plant according to a fifth aspect of the present invention provides the gas turbine plant according to any one of the first to fourth aspects, wherein an exhaust heat recovery boiler that generates steam from exhaust gas from the gas turbine and a waste heat recovery boiler It is characterized by combining with a steam turbine rotated by steam.
[0021]
In the combined plant of the present invention, the heat obtained by cooling the high-temperature portion of the gas turbine on the gas turbine plant side is consumed, so that heat transfer between cycles having greatly different operating temperature ranges is eliminated, and the heat loss associated therewith is reduced. Can be.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The components already described are given the same reference numerals or corresponding reference numerals in the drawings to simplify or omit the description.
[0023]
FIG. 1 is a schematic system diagram showing a configuration of a combined plant including a gas turbine plant P of the present invention. The combined plant includes a gas turbine 10, an exhaust heat recovery boiler 20, a steam turbine 30, and a closed loop refrigerant circulation system 100 for cooling a high-temperature portion of the gas turbine 10.
[0024]
The gas turbine 10 includes a compressor 11 that compresses air, a combustor 12 that burns fuel together with air discharged from the compressor 11, and a turbine that expands high-temperature combustion gas from the combustor 12 to turn a generator 15. 13 The combustion gas exhausted from the gas turbine 10 is supplied to an exhaust heat recovery boiler 20, where the main heat and the high-temperature combustion gas from the gas turbine 10 generate steam. Released to The generated steam is supplied to the high-pressure steam turbine 30A and the medium- and low-pressure steam turbine 30B according to the temperature and pressure conditions, and turns the generator 101 to generate electric power. The outlet steam of the middle and low pressure steam turbine 30 </ b> B is converted from steam into water by the condenser 32, and the subsequent water is pressurized by the feedwater pump 33 and returned to the boiler 20.
[0025]
In this plant, a closed loop circulation system 100 for cooling a high-temperature portion (turbine rotor blade 13A, turbine stationary blade 13B) of the gas turbine 10 is provided. The closed loop circulation system 100 circulates steam as a refrigerant, and includes heat exchangers 42A and 42B (first heat exchangers) arranged in a high temperature portion of a gas turbine on a circulation path, and a compressor 11 to a combustor 12 Heat exchanger 102 (second heat exchanger) disposed in the air introduction passage to the air, a condenser 104 for condensing steam after passing through the heat exchanger 102, a pump 106 for forcibly circulating water after condensation, and a pump 106 And a heater 108 for heating the water sent out at 106 to generate steam.
[0026]
In the gas turbine plant P, the high temperature portions of the gas turbine are cooled by the heat exchangers 42A and 42B by the steam circulating in the closed loop circulation system 100, and the air introduced into the combustor 12 is heated by the heat exchanger 102. Can be. Therefore, although a steam-cooled gas turbine is adopted, heat is exchanged within the same gas turbine cycle, so there is no heat transfer between cycles with greatly different operating temperature ranges, and heat loss due to heat transfer is reduced. Can be. Further, since the temperature of the air introduced into the combustor 12 can be increased by utilizing the steam that has been heated to a high temperature, the amount of heat input to the combustor 12 can be reduced, and the thermal efficiency of the gas turbine 10 can be improved. It can greatly contribute. In this case, the temperature of the air introduced from the compressor 11 to the combustor 12 can be raised by about 20 to 30 ° C.
[0027]
In actual operation, the condenser 104 is replenished with water in an amount corresponding to the amount of leaked steam in consideration of leakage of circulating steam. Further, in consideration of the warm-up at the beginning of operation, it is preferable to provide the auxiliary boiler 110 and supply the initial steam into the circulation path.
[0028]
Further, in the above-described embodiment, the steam after passing through the heat exchanger 102 is returned to water once by the condenser 104, sent out by the pump 104, heated by the heater 108 and converted into steam again, and the heat exchange of the gas turbine high-temperature portion is performed. Although they are directed to the vessels 42A and 42B, the entire path may be circulated as they are in the form of steam. In that case, an air supply device may be provided instead of the condenser 104, the pump 106, and the heater 108. However, when an air supply device is provided, the size of the device may be increased. Therefore, the configuration according to the present embodiment is preferable when the size of the device is reduced.
[0029]
Further, in the above-described embodiment, the case has been described where the temperature of the air introduced from the compressor 11 to the combustor 12 is increased by the heat obtained by cooling the high temperature portion of the gas turbine. By arranging the heat exchanger in the passage, the temperature of the fuel introduced into the combustor 12 can be increased.
[0030]
Further, in the above embodiment, the case of the moving blades and the stationary blades is described as an example of the gas turbine high temperature section, but the present invention may be applied to cooling of the high temperature section of the combustor 12.
[0031]
【The invention's effect】
As described above, according to the first aspect of the present invention, the heat obtained by cooling the high temperature portion of the gas turbine is used for raising the temperature of the air and fuel introduced into the combustor via the second heat exchanger. Therefore, heat transfer between cycles having greatly different operating temperature ranges can be eliminated, and heat loss due to heat transfer can be reduced. Further, the amount of heat input can be reduced by the amount of temperature rise of the introduced air and the introduced fuel, which can greatly contribute to the improvement of the thermal efficiency of the gas turbine. In addition, since the cooling system of the gas turbine high-temperature section is composed of a closed-loop circulation system, any medium can be used as a medium. A cooling system can be used.
[0032]
According to the second aspect of the present invention, since the steam as the medium is forcibly circulated by the air supply device, it is possible to produce a steam cooling gas turbine cycle having high thermal efficiency without receiving the supply of steam from the bottoming cycle. it can.
[0033]
According to the third aspect of the present invention, an efficient steam-cooled gas turbine cycle can be realized from the beginning of operation by adding the auxiliary boiler.
[0034]
According to the invention of claim 4, since the steam as the refrigerant is converted into water and circulated by the pump, the equipment can be simplified.
[0035]
According to the invention of claim 5, since the heat obtained by cooling the gas turbine high-temperature section on the gas turbine plant side is consumed, heat transfer between cycles having greatly different operating temperature ranges can be eliminated, and the heat loss associated therewith can be reduced. Can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic system diagram of a combine implant including a gas turbine plant according to an embodiment of the present invention.
FIG. 2 is a schematic system diagram of a comba implant including a conventional steam-cooled gas turbine.
[Explanation of symbols]
P Gas turbine plant 10 Gas turbine 11 Compressor 12 Combustor 13 Turbine 13A Moving blade (gas turbine high temperature section)
13B Stator vane (high temperature part of gas turbine)
42A, 42B heat exchanger (first heat exchanger)
100 closed loop circulation system 102 heat exchanger (second heat exchanger)
104 Condenser 106 Pump 108 Heater 110 Auxiliary boiler

Claims (5)

A gas turbine comprising a compressor that compresses air, a combustor that burns fuel together with air discharged from the compressor, and a turbine that expands high-temperature combustion gas from the combustor to obtain a mechanical output,
A first heat exchanger disposed in a high-temperature portion of the gas turbine, and a second heat exchanger disposed in at least one of an air introduction passage from the compressor to the combustor and a fuel introduction passage to the combustor. A closed-loop circulation system that circulates the medium between the heat sources and heats at least one of the air and the fuel introduced into the combustor with heat obtained by cooling a high-temperature portion of the gas turbine;
A gas turbine plant comprising: The gas turbine plant according to claim 1,
A gas turbine plant, wherein a medium circulated in the closed loop circulation system is steam, and an air supply device for forcibly circulating the steam is provided in the closed loop circulation system. The gas turbine plant according to claim 2,
A gas turbine plant comprising an auxiliary boiler for supplying steam into the closed loop circulation system at the time of starting the plant. The gas turbine plant according to claim 1,
The medium circulated through the closed loop circulation system is steam, and a condenser for condensing the steam after passing through the second heat exchanger and water condensed by the condenser are forced into the closed loop circulation system. A gas turbine plant comprising: a pump for circulating; and a heater interposed between the pump and the first heat exchanger, the heater for heating water sent by the pump to generate steam. . The gas turbine plant according to any one of claims 1 to 4, wherein an exhaust heat recovery boiler that generates steam by exhaust gas from the gas turbine and a steam turbine that is rotated by steam from the exhaust heat recovery boiler are combined. Combined plant characterized by that.

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