JPH0668373B2 - Method and apparatus for injecting steam into gas turbine combustor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for injecting steam into a gas turbine combustor, and more particularly to a method and apparatus for injecting steam that prevents combustion instability at the start of steam injection. .

[Conventional technology]

Nitrogen oxides (NO) emitted from gas turbine plants
In order to reduce x), steam is injected into the gas turbine combustor to lower the flame temperature.

Conventionally, as a steam injection to a gas turbine combustor, a method of injecting steam into compressor discharge air (Japanese Patent Laid-Open No. 55-82229)
No.) has been used. In this method, the steam is mixed with the whole air flowing into the combustor, so that the steam effectively acting to lower the flame temperature is only the steam contained in the combustion air flowing from the upstream part of the combustor, The steam contained in the cooling air or the dilution air on the wall surface of the combustor has almost no effect on reducing NOx.

Therefore, the low NOx effect by steam injection is not very high. On the other hand, since the vapor is uniformly mixed in the discharge air of the compressor, the adverse effect of lowering the combustion performance is relatively small.

In recent years, the demand for lowering NOx has increased, and a method of injecting steam into a combustion region has come to be adopted as a steam injection method that can obtain a large low NOx effect with a small amount of steam. This method is, for example,
Es, Ms, E 84-GT-48 (1984)
(Transaction of ASME).

Specifically, the steam is injected into the combustion region by injecting steam into the combustion air flow between the combustor liner cap and the outer cylinder cover, and spraying the flame around the combustion nozzle.

[Problems to be solved by the invention]

In the above-mentioned conventional technology, the bad influence on the combustion by the steam injection,
In particular, no consideration has been given to instability of combustion at the start of steam injection and misfire, and there is a problem that a misfire often occurs at the start of steam injection and the gas turbine plant stops.

This misfire phenomenon frequently occurs at the start of steam injection immediately after the start of the gas turbine when the outside temperature is low, and when the steam injection is stopped for a short time during continuous operation and the injection is restarted, or during the summer, etc. The frequency of occurrence is low when the outside temperature is high.

It is an object of the present invention to provide a steam injection method and apparatus that minimizes adverse effects on combustion at the start of steam injection and does not cause flame misfire.

[Means for solving problems]

The above object is achieved by completely removing the drain in the steam pipe from the boiler to the combustor before starting the steam injection, and preheating the pipe to a temperature at which steam does not condense in the pipe.

In particular, the piping on the downstream side of the steam flow rate adjusting valve provided in the steam line is achieved by backflowing the high temperature compressed air on the combustor side and discharging it from the vicinity of the adjusting valve to the atmosphere through the drain valve. To be done.

[Action]

According to the method, since the drain in the steam pipe is discharged to the outside of the pipe before the start of steam injection, the drain is not injected into the combustion region of the combustor at the start, and combustion instability such as misfire occurs. It can be prevented.

In addition, when drainage is discharged, high-temperature compressed air that flows backward from the combustor side to the drain valve preheats the piping, so steam can be prevented from condensing in the piping at the start of steam injection. Condensed water is not sprayed together with.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. The gas turbine includes a compressor 1, a combustor 2 and a turbine 3.
And is configured to drive the generator 4 as a load. The combustor 2 is supplied with the high pressure air 100 of the compressor 1 and the fuel 5,
The high temperature combustion gas 101 is supplied to the turbine 3,
Do the expansion work inside. Further, steam is supplied to the combustor 2 from a boiler 6 through a steam pipe 7. A steam flow control valve 8 and a steam flow meter 9 are attached to the steam pipe 7,
Further, an upstream drain extraction pipe 13 and an upstream drain valve 14 are provided in the vicinity of the upstream side of the steam flow rate adjusting piece 8, and a bypass pipe 1 provided with a drain separator 12 further upstream.
1 is attached. A downstream drain extraction pipe 15 and a downstream drain valve 16 are attached near the downstream of the steam flow control valve 8, and a drain separator 18 is provided further downstream thereof.
A bypass pipe 17 and a flow meter 9 are attached.
A steam supply pipe 10 is attached to and supplied to the combustor 2. As shown in FIG. 2, injecting steam into the combustor is provided with an annular steam header 24 inside the combustor outer cylinder cover 23, and a plurality of steam injection nozzles connected to the steam header 24 inside. Is installed and performed. In a gas turbine plant equipped with the steam injection facility having such a configuration, steam injection is performed according to the following procedure. When the steam injection is started in the operating state of the gas turbine, first, the steam flow rate control valve 8 is fully closed, and the upstream and downstream drain valves 14 and 16 of the steam flow rate control valve 8 are opened. As a result, the system from the boiler 6 to the steam flow control valve 8 completely removes the drain in the meantime by the steam from the boiler 6, and after removing the drain, the piping system is preheated to near the steam temperature. On the other hand, the steam flow control valve 8
From the combustor to the high pressure air 10 in the combustor.
Since 0 flows into the steam pipe with pressure through the steam injection nozzle 26, the steam header 24, and the short steam pipe 25, the drain during this time is completely removed by the high pressure air 100. After removing the drain, the high pressure air 100 is drained to the drain valve 1
Adjusting 6 allows high pressure air to flow 1
The pipe is preheated to a temperature close to 00. After such an operation, the drain valves 14 and 16 are closed, and the steam flow control valve 8 is opened at a predetermined valve opening speed to a valve opening degree that provides a predetermined flow rate, thereby completing the steam injection start operation. . The steam flow rate is automatically adjusted by feeding a signal from the steam flow meter 9 to the steam flow rate control valve 8 for feedback control.

In the above-mentioned embodiment, the steam pipes on the upstream side and the downstream side of the regulating valve 8 are purged of the drain by the high-temperature high-pressure fluid separate from the boiler steam and the compressed air in the combustor, and the pipes are preheated. Therefore, when the drain discharge operation is completed, the drain in the pipe 7 is completely discharged and the preheating is also completed, so that the combustion instability due to the mixture of the drain at the start of steam injection can be prevented. In the embodiment of FIG. 1, the regulating valve 8 divides the steam pipe 7 into two parts, which are divided into an upstream side and a downstream side.
Although purging is performed, a stop valve is provided near the boiler 6,
A drain valve is provided on the downstream side near the stop valve to start the steam injection, the stop valve is fully closed, the adjusting valve and the drain valve are fully opened, and most of the drain purge of the steam pipe 7 is performed.
Alternatively, the high pressure air from the combustor may be used.

In this case, a stop valve will be added, but since only one drain valve is required, it is structurally equivalent to the embodiment of FIG. For the above-mentioned opening / closing operation of the drain valve, a temperature detector is attached to each of the drain extraction pipes 13 and 15, and the extraction pipe 13 measures the steam temperature and the extraction pipe 15 measures the temperature of the high-pressure air to obtain an appropriate set temperature. You can also open and close automatically.

FIG. 3 shows a steam piping system in the case of a multi-can type combustor. In this case, steam is supplied to each combustor from a steam supply pipe 10 via a manifold pipe 26.
Since the steam pipe system of the multi-can combustor becomes complicated, all drain extraction pipes 13 and 15 are arranged so as to have a single gradient, and the horizontal level of the mounting position of each drain extraction pipe is set. Is the lowest rank. Also, the attachment of the steam pipe to the manifold pipe 26 is at the lowest level of the manifold pipe 26.

By using such a piping system and performing the purging operation described above, the drains of all the systems can be removed.

〔The invention's effect〕

According to the present invention, the drain in the steam pipe from the boiler to the gas turbine can be completely discharged, and the pipe can be preheated by steam and high-pressure, high-concentration air, so that the drain flows into the combustor at the time of steam injection. In addition, since the dry steam is flown even during the steam injection, the flow rate can be properly controlled, the impact on the flame during the steam injection can be significantly reduced, and a malfunction such as a misfire can be prevented.

[Brief description of drawings]

FIG. 1 is a steam injection piping system diagram of an embodiment of the present invention, and FIG.
The drawing is a cross-sectional view around the combustor in FIG. 1, and FIG. 3 is a steam injection piping system diagram of one embodiment applied to a multi-can combustor. 1 ... Compressor, 2 ... Combustor, 3 ... Turbine, 6 ...
Boiler, 7 ... Steam piping, 8 ... Flow control valve, 13 ...
Upstream drain extraction pipe, 14 ... Upstream drain valve, 1
5 ... Downstream drain extraction pipe, 16 ... Downstream drain valve, 23 ... Combustor outer cover, 24 ... Steam header, 2
6 ... Steam injection nozzle.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yorihide Segawa 502 Jinritsu-cho, Tsuchiura-shi, Ibaraki Machinery Research Institute, Hiritsu Manufacturing Co., Ltd. Machinery Research Laboratory (72) Inventor Kazuhiko Kumada 3-1-1, Saiwaicho, Hitachi City, Ibaraki Hitachi Ltd., Hitachi Works

Claims (9)

[Claims] 1. A steam turbine for a gas turbine combustor, comprising a steam pipe for injecting steam from a steam source into a combustion region of a gas turbine combustor, and a regulating valve and a drain valve in the pipe. After starting, using the drain valve, the compressed air in the combustor is discharged from the drain valve through the steam pipe, and the drain remaining in the steam pipe is discharged,
And, the compressed air is discharged from the drain valve until the temperature of the steam pipe reaches a predetermined temperature, after which the drain valve is closed and the steam from the steam source is injected into the gas turbine combustor. A method for injecting steam into a gas turbine combustor. 2. A steam pipe for guiding steam from a boiler to a combustion region of a gas turbine combustor, a steam flow rate adjusting valve provided in the pipe, and an upstream side and a downstream side of the adjusting valve near the adjusting valve. In a steam injection device to a gas turbine combustor having a drain valve and a drain valve, after the gas turbine is started, the adjusting valve is closed, the drain valves before and after that are opened, and the steam pipe on the upstream side of the adjusting valve is connected to the boiler The steam causes the piping on the downstream side of the regulating valve to purge the drain remaining in the piping and warm the piping with compressed air from the combustor.After that, both drain valves are closed and the regulating valve is opened to the combustion area. A method for injecting steam into a gas turbine combustor, characterized in that steam is injected. 3. A steam pipe for guiding steam from a steam source to a combustion region of a gas turbine, a stop valve provided in the pipe, and a first drain provided branching from a steam pipe downstream of the stop valve. A steam injection device for a gas turbine combustor, comprising: a valve. 4. The stop valve is a steam flow rate adjusting valve for adjusting the amount of steam flowing through the steam pipe, and is operated so as to be closed when the drain valve is opened. A steam injection device for a gas turbine combustor according to item 3. 5. The steam injection device for a gas turbine combustor according to claim 3, further comprising a second drain valve which is branched to a steam pipe upstream of the stop valve. 6. A steam injection nozzle opened in a gas turbine combustor, a steam pipe for supplying steam from a boiler to the nozzle, a steam flow rate adjusting valve provided in the pipe, and a downstream side of the adjusting valve. A first drain valve provided and a temperature sensor for detecting the temperature of the fluid discharged to the outside via the drain valve when the drain valve is open; Closed, the drain valve is opened and the drain in the steam pipe is purged by the compressed air in the combustor,
When the temperature of the fluid discharged from the drain valve reaches the specified value,
A steam injection device for a gas turbine combustor, characterized in that a drain valve is closed and a steam flow rate adjusting valve is opened. 7. The steam pipe further has a second drain valve branched from the steam pipe on the upstream side of the steam flow regulating valve, and the second drain valve is opened when the regulating valve is closed. 7. The steam injection device for a gas turbine combustor according to claim 6, wherein drainage in the steam pipe is purged. 8. A steam injection device for injecting steam from a boiler to a plurality of annularly arranged combustors through a steam pipe and a manifold pipe, wherein the steam pipe is provided near a lowermost position of the manifold pipe. A steam injection device for a gas turbine combustor, characterized in that the first drain valve is provided so as to communicate with the steam pipe downstream of a stop valve provided in the steam pipe. 9. A steam injection device for a gas turbine combustor according to claim 8, wherein a second drain valve is provided by branching to a steam pipe upstream of the stop valve.