JP2004316439A - Steam injection gas turbine power generating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steam injection gas turbine power generating device suppressing deterioration of exergy efficiency by effectively using latent heat of vaporization of steam generated by waste heat collection to generate low pressure saturated steam equivalent to a case of using a plurality of boilers with a simple structure, supplying steam to a external process, and preventing generation of white smoke when gas is discharged to atmosphere. <P>SOLUTION: The steam injection gas turbine power generating device including a compressor, a burner, a gas turbine comprised of a turbine, an economizer, an evaporator and a superheater is provided with a steam superheater superheating saturated steam generated by the evaporator, a steam expander generating electric power by steam superheated by the steam superheater, an expansion valve generating wet steam by expanding feed water superheated by the economizer, an steam water separator separating rest of wet steam generated by the expansion valve into saturated steam and saturated water, a first flow passage mixing the separated saturated water into feed water of the economizer, and a second flow passage mixing the separated saturated steam and high temperature steam flowing out of the steam expander and injecting the same into the burner. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam injection gas turbine power generator.
[0002]
[Prior art]
[0003] A steam injection type gas turbine is a system in which steam generated by exhaust heat is injected into the turbine to increase the generated power, and a typical example is a chain cycle shown in FIG. In FIG. 5, the feed water heated by the economizer is injected into the exhaust heat recovery boiler, and the saturated steam generated by the exhaust heat recovery boiler is further heated by the steam superheater and injected into the combustor as superheated steam.
In recent years, Patent Documents 1 to 3 have been proposed as related technologies.
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-129984 [Patent Document 2]
JP-A-11-280493 [Patent Document 3]
[0005] Japanese Patent Application No. 2001-320687 discloses a technique for preventing white smoke generated from a chimney in gas turbine equipment shown in FIG. 5 for injecting water or steam into a gas turbine. . For this reason, a part of the high-temperature exhaust gas discharged from the gas turbine is mixed with the low-temperature exhaust gas in the chimney, whereby the temperature of the exhaust gas from the chimney is raised to such an extent that white smoke is not generated.
[0006] Patent Document 2 discloses a gas turbine facility for injecting water or steam shown in FIG. 5 into a gas turbine, in which energy of high-temperature steam heated by high-temperature exhaust gas discharged from the gas turbine is used by another steam turbine. By recovering, the amount of exchange of heat energy per unit steam amount is increased.
[0007] Patent Document 3 discloses a gas turbine facility for injecting water or steam into a gas turbine as shown in FIG. 5, in which a boost compressor rotationally driven by the gas turbine is used to flow into a combustor. It increases the amount of hot steam. As a result, the power generation output and the thermal efficiency are improved by effectively utilizing the surplus steam that has not been used conventionally.
[0008]
In these patent documents, there is a problem that the latent heat of vaporization of the steam provided by the exhaust heat of the gas turbine is not finally recovered as work but exhausted to the atmosphere together with the exhaust gas. is there. Further, in order to reduce the loss of exergy efficiency in exhaust heat recovery, a method of using a plurality of boiler drums is generally employed, but in this case, there is a problem that the system becomes complicated. Further, in the conventional steam injection gas turbine generator, as pointed out in Document 1, the ratio of water vapor in the exhaust gas is high, and there is a problem that water vapor is easily condensed in the atmosphere to generate white smoke.
The present invention has been made to solve the above-mentioned various problems. That is, (1) an object of the present invention is to effectively utilize the latent heat of vaporization of steam generated by exhaust heat recovery and generate low-pressure saturated steam similar to the case of using a plurality of boilers with a simple configuration, thereby achieving exergy efficiency. And (2) a steam injection gas turbine power generator capable of supplying steam to an external process, and (3) preventing generation of white smoke when exhausting gas into the atmosphere. Is to do.
[0010]
[Means for Solving the Problems]
According to the present invention, in a steam injection gas turbine power generator having a compressor, a combustor, a gas turbine including a turbine, an economizer, an evaporator, and a superheater, steam for heating saturated steam generated in the evaporator is provided. A superheater, a steam expander that generates power using the steam superheated by the steam superheater, an expansion valve that expands the feedwater superheated by the economizer to generate wet steam, and a remainder of the wet steam generated by the expansion valve. Separator for separating water into saturated steam and saturated water, a first flow path for mixing the separated saturated water into the feed water of the economizer, and mixing the separated saturated steam with high-temperature steam flowing out of the steam expander for combustion And a second flow path for injecting the gas into the steam generator.
According to the configuration of the present invention described above, the high-temperature feedwater heated by the economizer is flushed by the expansion valve and reduced in pressure. After the high-pressure saturated water and the saturated steam are generated by the reduced pressure, the high-pressure saturated water is separated into the saturated water and the saturated steam by the steam separator. Furthermore, the saturated water is mixed with the supply water of the economizer, heated by the in-line mixing heater, mixed with make-up water, and heated and circulated by the economizer, thereby effectively utilizing the latent heat of vaporization to raise the temperature of the circulating supply water. As a result, the temperature of the exhaust gas discharged into the atmosphere can be increased to prevent the generation of white smoke.
Further, the separated saturated steam can be used as steam equivalent to low-pressure steam in a double-pressure boiler having a plurality of drums.
The feedwater heated by the economizer is partially supplied to the evaporator and used to maintain the pressure in the boiler. The steam generated by heating in the evaporator is further heated by the steam superheater, so that the inlet temperature of the steam superheater can be sufficiently increased. Thereby, the temperature difference and the pressure difference between the inlet and the outlet of the steam expander can be increased, and energy can be recovered in the steam expander.
The low-pressure steam after passing through the expansion valve and after passing through the steam expander can be injected into the combustor after being heated by the low-pressure steam superheater. In general, in order to perform combustion in a combustor, considering that there are restrictions on the temperature, pressure, and flow rate of the steam to be injected, this configuration can efficiently utilize these characteristics to efficiently convert energy. .
According to the present invention, there is provided a third flow path for supplying a part of the separated saturated steam to the feed water, and the third flow path has a steam flow regulating valve and an in-line mixing heater. A steam injection gas turbine power generator is provided.
According to the configuration of the present invention described above, it is possible to adjust the opening of the steam flow control valve in accordance with the degree of generation of white smoke and adjust the temperature of the circulating water by the separated steam. In addition, excess steam can be used as process steam or injected into a combustor.
According to the present invention, there is provided a steam-injected gas turbine power generator, wherein a low-pressure steam heater is provided in the second flow passage.
According to the configuration of the present invention described above, even after the calorific value of the steam supplied to the combustor is deprived, it is possible to perform heating by the low-pressure steam superheater and to feed the steam into the combustor. Here, the case where the calorie of the steam is taken away is, for example, a case where a large amount of steam separated from the brackish water separator is mixed with circulating water to prevent white smoke, a case where a large amount of process steam is supplied to the outside, and the like. Is shown.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be described with reference to the drawings. In each of the drawings, common portions are denoted by the same reference numerals, and redundant description is omitted.
FIG. 1 is a conceptual diagram showing a first embodiment of the present invention. In this embodiment, the supplied makeup water is pressurized by a water supply pump and supplied to the economizer. The economizer heats the water supply using exhaust gas. Part of the supply water heated by the economizer is supplied to the evaporator, and the rest is supplied to the expansion valve. The supply water is expanded by the expansion valve, so that saturated water and steam are mixed. By passing the mixture of water and steam through the brackish water separator, saturated water and saturated steam are separated and generated. Thereafter, the separated saturated water is supplied to the makeup water, and the saturated steam is supplied to the combustor.
On the other hand, the water heated by the economizer and supplied to the evaporator is superheated by the superheater, becomes superheated steam, and is supplied to the steam expander. The steam expander generates power using superheated steam. Further, the steam after the power generation is mixed with the steam separated by the steam separator and supplied to the combustor.
Exhaust gas generated by the combustor is recovered by a turbine to drive a compressor and a generator. The compressor compresses oxygen after inhaling oxygen from the outside and supplies it to the combustor to increase combustion. Further, the generator generates electric power by using the recovered power. The exhaust gas whose power has been recovered is heated as a superheater, an evaporator, and an economizer for preventing white smoke, and then discharged into the atmosphere as exhaust gas.
FIG. 2 is a diagram showing a second embodiment of the present invention. In this embodiment, a part of the steam separated by the brackish water separator is mixed into the water supply to the economizer via the saturated steam valve and the in-line mixing superheater, so that the water supply to the economizer is prevented when white smoke is prevented. The temperature can be controlled.
FIG. 3 is a diagram showing a third embodiment of the present invention. In this embodiment, the mixed steam of the saturated steam separated by the steam separator and the steam discharged from the steam expander is superheated by a low-pressure steam superheater and then injected into the combustor. A part of the saturated steam separated from the steam separator is directly injected into the combustor.
FIG. 4 shows an exhaust heat recovery diagram in the embodiment of FIG. In this figure, the pressure of the exhaust heat recovery boiler is set to 40 ata. The temperature of the gas turbine exhaust gas is 87 degrees. Further, in this example, the power generation output is about 6400 Kw, and the power generation efficiency is about 40.85%. In this embodiment, make-up water is supplied at about 60 degrees and 13.1 ata, and is pressurized to about 40 ata by a water supply pump and an expansion valve. Further, it is superheated to about 250 degrees by an evaporator and a superheater, and is sent to a steam expander as superheated steam. In the exhaust heat recovery diagram, the amount of heat exchanged by steam falls from about 450 degrees to about 350 degrees near 2500 Kcal / s, which indicates the conversion of energy into power by the steam expander. The steam is thereafter heated by a low-pressure steam superheater and supplied to the combustor. By superheating the steam injected into the combustor by the low-pressure steam superheater, not only can the output / efficiency be improved as in the conventional example, but also the steam supply to the water supply to prevent white smoke and the steam Exergy loss can be reduced even when the temperature of the steam introduced into the combustor decreases due to power generation by the expander and steam supply to the process.
In the steam injection gas turbine power generator of the invention described above, a part of the saturated water generated by the feed water pump, the expansion valve, and the steam separator is used for white smoke prevention, and the steam generated by the evaporator is used. By mixing with the steam generated by the above-mentioned steam separator, the steam can be supplied to the process.
Note that the present invention is not limited to the above-described embodiment, and it is a matter of course that various changes can be made without departing from the gist of the present invention.
[0021]
According to the present invention described above, the following effects can be obtained.
1. The condensed water contained in the outlet of the steam expander is obtained by converting a part of the latent heat of the steam by the exhaust heat recovery boiler into the shaft power of the expander and the sensible heat of the steam. Part of the water supplied to the steam expander is separated into saturated water and saturated steam by an expansion valve and a steam separator, and the saturated water can be removed from the system without re-evaporating. Therefore, the latent heat of vaporization contained in the exhaust gas is effectively recovered, and the cycle efficiency is improved.
In addition, the operation of circulating water from the economizer through the expansion valve and the brackish water separator to the economizer again to obtain low-pressure steam as flash steam in the process can generate low-pressure steam without a boiler drum, At the outlet, it also plays a role in creating a gas-liquid mixed phase state with a predominantly liquid phase. This condition makes it possible to efficiently separate the condensate mist slightly contained in the steam exiting the steam expander. That is, the same effect as the exhaust heat recovery by the double-pressure steam for improving the cycle rate can be realized by one drum.
2. With the structure in which the steam output from the steam expander is introduced into the combustion chamber without passing through the steam separator, the steam used for other processes can be taken out and used during the process. Therefore, it is possible to use the process steam in accordance with the needs of the user.
3. Even if the temperature of the steam supplied to the combustor decreases due to the steam expander, prevention of white smoke, and supply to the process, exergy loss can be reduced by being superheated by the low-pressure steam superheater. .
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a first embodiment of a steam injection gas turbine power generator of the present invention.
FIG. 2 is a configuration diagram of a second embodiment of the steam injection gas turbine power generator of the present invention.
FIG. 3 is a configuration diagram of a third embodiment of the steam injection gas turbine power generator of the present invention.
FIG. 4 is an exhaust heat recovery diagram of FIG. 3;
FIG. 5 is a configuration diagram of a conventional steam injection gas turbine power generator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Gas turbine 1a Compressor 1b Combustor 1c Turbine 2 Generator 2a Reduction gear 3a Economizer 3b Evaporator 3c Superheater 3d Low-pressure steam superheater 3f Water feed pump 10 Steam injection gas turbine generator 12 Steam expander 14 Steam separator 16 Expansion Valve 18 In-line mixing superheater 18a Steam flow control valve 21 First flow path 22 Second flow path 23 Third flow path

Claims (3)

A compressor, a combustor, a gas turbine including a turbine, an economizer, and an evaporator and a superheater.
A steam superheater for heating the saturated steam generated in the evaporator,
A steam expander that performs power generation with the steam superheated by the steam superheater,
An expansion valve that expands the supply water heated by the economizer to generate wet steam,
A brackish water separator that separates the remainder of the wet steam generated by the expansion valve into saturated steam and saturated water,
A first flow path for mixing the separated saturated water into the water supply to the economizer,
A steam injection gas turbine power generator, comprising: a second flow path that mixes the separated saturated steam with high-temperature steam flowing out of a steam expander and injects the mixed steam into a combustor. 2. The apparatus according to claim 1, further comprising: a third flow path configured to supply a part of the separated saturated steam to feed water, wherein the third flow path includes a steam flow control valve and an in-line mixing heater. 3. Steam injection gas turbine power generator. The steam injection gas turbine power generator according to claim 1, wherein a low-pressure steam heater is provided in the second flow path.

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