JP3825091B2 - Combined cycle power plant - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combined cycle power plant that combines a gas turbine plant and a steam turbine plant.
[0002]
[Prior art]
A combined cycle power plant is a power generation system that combines a gas turbine plant and a steam turbine plant. The high temperature region of the thermal energy is shared by the gas turbine, and the low temperature region is shared by the steam turbine. It is a power generation system that has been collected and used, and has been particularly in the spotlight in recent years.
[0003]
In this combined cycle power plant, research and development has been advanced with one point for improving the efficiency as to how far the high temperature range of the gas turbine can be increased.
[0004]
On the other hand, in order to form a high temperature region, a cooling system must be provided from the viewpoint of heat resistance of the turbine structure, and air has been conventionally used as a cooling medium in this cooling system.
[0005]
However, as long as air is used as the cooling medium, even if a high temperature range can be achieved, the power loss required for boosting the air required for cooling to the required pressure with its own air compressor, and the high temperature gas Considering both the fact that the average gas temperature is lowered by finally mixing the air used for cooling the parts in the turbine passage through which the gas passes, resulting in lowering the energy of the gas. We can't expect any further improvement.
[0006]
In order to solve this problem and further improve the efficiency, it has been proposed to use steam instead of the air as the cooling medium of the gas turbine.
[0007]
As an example, there is one disclosed in Japanese Patent Application Laid-Open No. 05-163960. However, what is disclosed in Japanese Patent Application Laid-Open No. 05-163960, apart from the disclosure of the concept of using steam as a cooling medium for a gas turbine, there are still many problems that must be devised and solved in detail. ing.
[0008]
For example, steam that has been heated to a high temperature by cooling a high-temperature cooling section of a gas turbine is merged with steam supplied from a reheater and introduced into an intermediate pressure turbine. The current situation is that there is no consideration and examination about the point of how to join, in what kind of position, specifically, it is only shown as a working steam supply system .
[0009]
That is, the attempt to cool the high-temperature cooling part of the gas turbine with steam is still in a trial and error stage, and there are actually many problems that must be solved.
[0010]
[Problems to be solved by the invention]
As described above, as a conventional technique including the one disclosed in Japanese Patent Laid-Open No. 05-163960, there has been no special investigation on mixing of a plurality of steams to be introduced into an intermediate pressure turbine, and there is a problem awareness. I can't find any.
[0011]
However, since the steam heated at the high temperature cooling section of the gas turbine as described above is heated and the steam supplied from the reheater has different conditions such as pressure and temperature, such steam is insufficient. In the case of being introduced into an intermediate pressure turbine with proper mixing, steam at a higher temperature than the set temperature or steam at a lower temperature will be put into the turbine as it is, which may damage the turbine body. There is a risk of inviting.
[0012]
In addition, if a structure in which the plurality of steams to be mixed are brought to the vicinity of the intermediate-pressure turbine while being in the piping is used, the amount of piping is increased, and the cost is immediately increased. Furthermore, there is a concern that a temperature difference occurs in the pipe and the pipe is cracked due to thermal stress.
[0013]
An object of the present invention is to provide an apparatus that prevents the occurrence of such problems when mixing a plurality of steams, ensures the safety of the apparatus, and operates stably over a long period of time.
[0014]
[Means for Solving the Problems]
The present invention, the problems intended to have been resolved all Kunasa, combining a gas turbine plant and a steam turbine plant, comprising a heat recovery steam by utilizing exhaust heat from a gas turbine to generate steam turbine driving steam In addition, in a combined cycle power plant configured to provide a steam cooling system that cools a high-temperature cooled part of the gas turbine with steam, and to collect the superheated steam from the steam cooling system in the steam turbine, the steam cooling system includes: A mixing pipe for mixing the outlet steam and the bypass steam is provided , and the mixing pipe includes a steam inlet from the pipe end and steam inlets from a plurality of pipe sides, and the inlet from the pipe side. combined cycle is that while being spaced tube longitudinal direction and arranged remembering angle inlet adjacent to each other in the circumferential direction An electric plant is provided to control the flow rate and temperature of the outlet steam that is heated by cooling the high-temperature cooled part of the gas turbine and comes out of the steam cooling system, and the introduced steam of the high-temperature cooled part. By introducing the bypass steam that has been bypassed without being introduced into the high-temperature cooled part into the mixing tube and mixing it, a mixed superheated steam with uniform pressure, temperature, etc. is formed, and this mixed superheated steam Is recovered by a downstream steam turbine, for example, an intermediate pressure turbine.
[0015]
In the present invention, as described above, the installation position of the steam inlet is divided into the tube end portion and the tube side portion, and those from the tube side portion are spaced apart in the longitudinal direction of the tube and adjacent to each other. Since the matching items have an angle in the circumferential direction, a plurality of vapors with different conditions entering from the respective steam inlets can be mixed well so as to achieve uniform conditions It is.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
[0017]
A gas turbine plant 100 includes a gas turbine 101, an air compressor 102 driven by the gas turbine 101, and a combustor 103 that burns compressed air supplied from the air compressor 102 together with fuel as main components. Yes.
[0018]
An exhaust heat recovery boiler 200 uses the exhaust gas of the gas turbine 101 as a heating source, and includes a high-pressure steam generator 201, an intermediate-pressure steam generator 202, and a low-pressure steam generator 203 as main parts.
[0019]
Reference numeral 300 denotes a steam turbine plant. From the high-pressure turbine 301 to which high-pressure steam is supplied from the exhaust heat recovery boiler 200, the intermediate-pressure turbine 302 to which steam from a steam recovery system 405, which will be described later, and the exhaust heat recovery boiler 200 are supplied. Low-pressure steam is supplied and the low-pressure turbine 303 is configured as a main device.
[0020]
A steam cooling system 400 includes a cooling steam supply system 401 connected to the exhaust 304 of the high-pressure turbine 301, a first steam cooling system 402 that branches from the cooling steam supply system 401 and cools the combustor 103, Similarly to the first steam cooling system 402, the second and third steam cooling systems 403 and 404 that branch from the cooling steam supply system 401 and cool the high-temperature cooled parts of the gas turbine 101 are configured as main devices. Has been.
[0021]
Reference numeral 500 denotes a bypass system, which is arranged in parallel with each cooling system to control the flow rate and temperature of the steam introduced into the first to third steam cooling systems 402, 403, 404. 3 bypass systems 501, 502, and 503.
[0022]
Reference numeral 700 denotes a mixing pipe, which has a steam inlet 701 at the pipe end and a plurality of steam inlets 702, 703, 704, 705 at the pipe side. The second and third steam cooling systems 403 and 404 that cool the high-temperature cooled parts of the pipe are connected to the steam inlet 702 on the side of the pipe of the first steam cooling system 402 that cools the combustor 103. The other steam inlets 703, 704, 705 connected to the system bypass the first to third steam cooling systems 402, 403, 404 and the first to third bypass systems 501, A supply of bypass steam flowing through 502 and 503 is received.
[0023]
A steam outlet 706 is provided at the other end of the pipe and communicates with the intermediate pressure turbine 302 via a steam recovery system 405.
[0024]
The steam inlets 702, 703, 704, and 705 on the side of the tube are spaced apart in the longitudinal direction of the tube and arranged at an angle of 90 degrees in the circumferential direction.
[0025]
A steam outlet 706 is located at the end of the pipe opposite to the steam inlet 701 and communicates with the inlet of the intermediate pressure turbine 302.
[0026]
Here, four steam inlets 702 to 705 are provided on the side of the pipe, separated upstream and downstream, and arranged at an angle of 90 degrees in the circumferential direction. It is needless to say that the direction and the like are not limited to this, and can be appropriately changed to 90 degrees or an intermediate angle depending on the number and properties of the steam sources to be mixed.
[0027]
In addition, the position where the mixing pipe 700 is disposed is merely schematically shown in FIG. 1, but is actually disposed as close as possible to the outlet of the high temperature cooled portion of the gas turbine 101, As a result, the arrangement is preferably such that the distance from the steam outlet 706 to the intermediate pressure turbine 302 is as long as possible.
[0028]
Since the present embodiment is configured as described above, the outlet steam from the second and third steam cooling systems 403 and 404 heated by cooling the high temperature cooled part of the gas turbine 101 is piped. The steam was supplied to the mixing pipe 700 from the steam inlet 701 at the end, and the steam and the combustor 103 were cooled and supplied to the mixing pipe 700 from the first steam cooling system 402 via the steam inlet 702 on the side of the pipe. Each of the outlet steam and the bypass steam supplied from the other steam inlets 703, 704, 705 to the mixing pipe 700 through the first to third bypass systems 501, 502, 503 is supplied to the mixing pipe 700. It is mixed in and becomes mixed superheated steam.
[0029]
At this time, the exit steam entering from the steam inlet 701 at the end of the pipe advances in the axial direction of the mixing pipe 700, and from the steam inlet 702 and other steam inlets 703 to 705 on the side of the pipe with respect to this steam flow. The supplied steam has the same steam inlets 702, 703, 704, and 705 spaced apart in the longitudinal direction of the mixing tube 700 and at an angle of 90 degrees in the circumferential direction (or in the middle). Since they are arranged, mixing is performed sequentially at different positions along the flow direction, and the steams having different conditions entering from the respective steam inlets 701, 702, 703, 704, and 705 are well mixed. Thus, mixed superheated steam having uniform pressure, temperature, etc. can be formed.
[0030]
This mixing is performed by placing the mixing pipe 700 as close as possible to the outlet of the gas turbine high temperature cooled section, and concentrating each steam immediately after the gas turbine high temperature cooled section, thereby leaving the mixing pipe 700. In addition, since the distance of the path to the intermediate pressure turbine 302 can be formed with a margin, uniformizing the conditions of the mixed superheated steam is further promoted, and the amount of pipes is reduced and the cost is greatly reduced.
[0031]
In this way, according to the present embodiment, the condition of the mixed superheated steam recovered by the intermediate pressure turbine is made uniform to prevent damage to the intermediate pressure turbine, and further, the amount of piping is reduced and the cost is greatly reduced. To do.
[0032]
Although the present invention has been described with reference to the illustrated embodiment, the present invention is not limited to this embodiment, and it goes without saying that various modifications may be made to the specific structure within the scope of the present invention. Absent.
[0033]
【The invention's effect】
As described above, according to the present invention, a plurality of steams having different conditions such as pressure and temperature are collected from the inlets provided at the pipe end and the pipe side part, and these conditions form a uniform superheated steam. Since it is collected by a downstream steam turbine, for example, an intermediate pressure turbine, unnecessary troubles such as damage to the steam turbine due to unstable steam conditions and cracks in the piping can be avoided. .
[0034]
In addition , according to the present invention, when the mixed superheated steam is formed, the plurality of steams having different conditions are formed by forming the positional relationship of the plurality of steams entering the mixing pipe from the side of the pipe at an angle in the circumferential direction. Thus, the uniform mixing of the steam turbine is surely promoted, the stabilization of the steam turbine described above is ensured, and the stability and reliability of the system can be obtained.
[Brief description of the drawings]
FIG. 1 is a system diagram of a combined cycle power plant according to an embodiment of the present invention.
FIG. 2 is an explanatory view of a mixing tube extracted from the mixing tube shown in FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 Gas turbine plant 101 Gas turbine 102 Air compressor 103 Combustor 200 Waste heat recovery boiler 201 High pressure steam generation part 202 Medium pressure steam generation part 203 Low pressure steam generation part 300 Steam turbine plant 301 High pressure turbine 302 Medium pressure turbine 303 Low pressure turbine 304 Exhaust unit 400 Steam cooling system 401 Cooling steam supply system 402 First steam cooling system 403 Second steam cooling system 404 Third steam cooling system 405 Steam recovery system 500 Bypass system 501 First bypass system 502 Second bypass System 503 Third bypass system 700 Mixing pipe 701 Steam inlet 702 Steam inlet 703 Steam inlet 704 Steam inlet 705 Steam inlet 706 Steam outlet

Claims (1)

A gas turbine plant and a steam turbine plant are combined, and an exhaust heat recovery boiler that generates steam for driving a steam turbine using exhaust heat from the gas turbine is provided, and a high-temperature cooled part of the gas turbine is cooled with steam. In a combined cycle power plant configured to provide a steam cooling system and to collect the superheated steam from the steam cooling system in a steam turbine, a mixing pipe for mixing the outlet steam and bypass steam of the steam cooling system is provided , and The mixing pipe includes a steam inlet from the pipe end and steam inlets from a plurality of pipe sides, and the inlets from the pipe side are arranged at intervals in the longitudinal direction of the pipe and adjacent to each other. A combined cycle power plant characterized in that matching inlets are arranged at an angle in the circumferential direction .

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