JPH01178728A - Steam injection equipment for gas turbine - Google Patents

Abstract

PURPOSE:To prevent a flame of a combustor from blowing out by setting up each heater wire in steam pipelines between a steam flow regulating valve and the combustor. CONSTITUTION:Each steam pipeline 23 is installed in place ranging from a steam turbine or a exhaust heat recovery heat exchanger to a combustor 2. Each heater wire is set up in an interval between a steam flow regulating valve 11 of this steam pipeline 23 and the combustor 2, heating the heater wire 24, and temperature control over the steam pipeline 23 takes place. With this constitution, any liquefaction of injection steam at the time of steam jet starting is checked, so that any possible blowout of a flame inside the combustor 2 is preventable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a steam injection device for a gas turbine that reduces nitrogen oxides in gas turbine exhaust gas.

(Prior Art) The structure of a conventional gas turbine plant is as shown in FIG. A process C in which the resulting high-temperature, high-pressure combustion gas expands, the gas turbine rotor 4 attached to the gas turbine 3 is rotated, and the gas turbine rotor 4 is installed coaxially with the electric power generator. The structure is such that electric energy is obtained by rotating the machine 5.

In recent gas turbine plans 1 to 2, the efficiency of the plant is increased by increasing the combustion temperature of combustion gas in the combustor 2 to 10 R, but increasing the combustion humidity causes nitrogen in the air to oxidize. Nitrogen oxides (F), which are harmful to the human body,
(referred to as NO) occurs. Therefore, in conventional gas turbine plants,
Steam is injected into the combustion flame to lower the combustion temperature and NO
A steam injection device M6 is provided which reduces x.

This steam injection device 6 extracts steam from an exhaust heat recovery heat exchanger 7 or a steam turbine 8 and guides it to a desuperheater 9 where the temperature of the steam is lowered. The structure is such that steam passes through a control valve 11 and is injected from a steam manifold 12 into the combustor 2. A path for guiding steam from the exhaust heat recovery heat exchanger 7 and the steam turbine 8 to the steam manifold 12 through the desuperheater 9 and the like is the steam piping 1.
Consisting of 3. In this way, injecting low-humidity steam into the combustion flame reduces the combustion temperature.
It reduces the generation of Ox.

Additionally, ammonia gas is injected and mixed into the exhaust gas after steam injection and after the turbine is driven, and the exhaust gas is passed through a catalyst on the downstream side to further completely reduce NOx.

Figure 6 shows the change in NOx emissions from gas turbine ignition until the turbine reaches rated operation. First, NOx is emitted at the same time as the gas turbine ignites, and while the gas turbine is warmed up for a certain period of time at a certain rotation speed, the amount of NOx emitted from the gas turbine remains constant. Next, when the turbine rotation speed increases from the gas turbine warm-up end point to the FSNL (rated rotation speed no load) state, the amount of NOx emissions increases almost in proportion to the turbine rotation speed. Eventually, after passing FSNL, the displacement increases according to the load on the engine, and reaches its peak during minimum load operation (Spinning Re5erve).

Therefore, in order to reduce the amount of NOx discharged, steam is injected into the combustion flame within the combustor 2 to obtain the NOx characteristics as shown by the dashed-dotted line A in FIG.

However, this is still not sufficient from the viewpoint of pollution control, so by further injecting ammonia gas into the exhaust gas from the gas turbine 3 and passing it through the sulfur catalyst, NOx as shown by the solid line B in Fig. 6 can be reduced. These characteristics have led to further reductions in NOx.

(Problem to be Solved by the Invention) However, in the conventional gas turbine steam injection device as described above, the atmospheric temperature in the steam pipe 13 between the downstream side of the steam flow rate control valve 11 and the steam manifold 12 is lower than that of the atmosphere. Since the temperature is almost the same as the temperature, the temperature of the steam passing through the steam pipe 13 decreases and liquefies at the start of steam injection, and this liquefied steam is directly blown onto the combustion flame in the combustor 2. There was a risk that the flame would be extinguished and the gas turbine would shut down.

This invention was made in consideration of the above facts,
An object of the present invention is to provide a steam injection device for a gas turbine that can prevent liquefaction of steam at the start of steam injection and prevent combustion flames from blowing out in a combustion chamber.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a steam pipe for guiding steam extracted from a steam turbine or an exhaust heat recovery heat exchanger into a combustor, a steam pipe installed in the steam pipe, and a steam pipe installed in the steam pipe. A steam turbine for reducing nitrogen oxides in turbine exhaust gas by injecting steam led from the steam piping into a combustion flame in the combustor, and reducing nitrogen oxides in the turbine exhaust gas. In the injection device, a heater wire is disposed in the steam piping between the downstream side of the steam flow rate control valve and the combustor, and the heater wire is heated to adjust the temperature of the steam piping. be.

(Function) Therefore, according to the steam injection device for a gas turbine according to the present invention, the steam piping between the downstream side of the steam flow rate control valve and the combustor is heated by applying electric power to the heater wire from the power supply device, The injection steam flowing between the pipes should not be liquefied in the steam piping.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a system diagram showing a part of a gas turbine blanc 1 to which an embodiment of a gas turbine steam injection device according to the present invention is applied, and FIG. 2 is a perspective view showing the configuration of this embodiment. . In this embodiment, parts similar to those in the prior art example are denoted by the same reference numerals, and a description thereof will be omitted.

As shown in FIG. 1, two steam pipes 23 are provided to connect the downstream side of the steam flow rate control valve 11 and the steam manifold 12, and the heater wires 24 are tightly attached to the outer peripheries of these steam pipes 23. Installed (installed).

As shown in FIG. 2, this heater wire 24 is formed into two steam pipes and is raced from the steam flow rate control valve 11 to the steam manifold 12 with one heater wire. This heater wire 2/I exits from the steam pipe 23 at a position immediately after the steam flow rate control valve 11, and is connected to the power supply device 25 to be supplied with electric power.

The power supply device 25 is provided with a switch (not shown), and the ON/OFF operation of this switch determines whether power is supplied to the heater wire 24 or not, in other words, whether or not the steam pipe 23 is heated. In other words, before the start of steam injection, turn on the switch to energize the heater wire 24 and warm the steam pipe 23.After the start of steam injection, there is no need to warm up the steam pipe 23, so the power supply Turn off the switch 25
shall be.

Next, an example of a structure for closely fixing the steam sparrow 23 and the heater wire 24 will be described with reference to FIG. 3.

A heater wire 24 is disposed in close contact with the outer periphery of the steam pipe 23 along the axial direction of the steam pipe 23 . In order to tightly fix the heater wire 24 to the steam pipe 23, the heater wire 24 and the steam pipe 23 are simultaneously wound around the reinforcing wire 26 at a suitable number of locations in the axial direction of the steam pipe 23. Then, a heat insulating material 27 is provided around the outer periphery of the steam pipe 23 and the heater wire 24 for insulation from the outside, and a hard cover 28 for protecting the steam pipe is further provided to cover the outer periphery of the heat insulating material 27. A reinforcing wire 29 for fixing the hard cover 28 is wound around the hard cover 28 in various places in the axial direction and overlapped several times on the outer periphery of the hard cover 28.
is covered to form one line.

In this gas turbine steam injection system having this configuration, before starting steam injection into the combustion flame in the combustor of the gas turbine, the switch of the power supply device 25 is turned on to supply power to the heater wire 24. The heater wire 24 is connected to the steam pipe 23 between the steam flow rate control valve 11 and the steam manifold 12.
Since the heat of J: can be prewarmed, even if the steam pipe 23 is in a low-temperature environment, the injected steam in the steam pipe 23 can be prevented from liquefying. As a result of (a), even if the injection steam is injected into the combustion chamber, the combustion flame will not blow out and the gas turbine will not stop.

In addition, as another effect, it is possible to prevent the injected steam from liquefying even if the steam pipe 23 is in a low-temperature environment, so even if the injected steam is at a lower temperature than conventional methods, the injected steam can be heated and injected. . In other words, as shown at time C in FIG. 4, steam injection can be started earlier than in the past. As a result, the peak N0xl during gas turbine startup
Jl output can be significantly reduced, and operation is possible even under conditions with strict NO8υ1 output regulations. The broken line in Figure 4 indicates the amount of NO8 emitted after the start of steam injection.
The solid line [indicates the NO8 emission amount when ammonia is injected into the exhaust gas after the start of steam injection.

[Effects of the Invention] As described above, according to the steam injection device for a gas turbine according to the present invention, the steam piping to the gas turbine can be warmed before the start of steam injection, so that the injected steam flowing at the start of steam injection can be heated. It is possible to prevent the combustion flame from blowing out in the combustor, which is caused by the liquefaction of the injected steam.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing a part of gas turbine plan 1 to which an embodiment of the gas turbine steam injection device according to the present invention is applied, and FIG. 2 shows the configuration of the embodiment of FIG. 1. FIG. 3 is a perspective view showing the tight fixation structure of the steam piping and heater wire in this embodiment, and FIG. NO
Fig. 5 is a system diagram showing a gas turbine plant to which a conventional gas turbine steam injection device is applied, and Fig. 6 is a diagram showing the gas turbine plant shown in Fig. 5).
) is a diagram that does not show the amount of NO emissions from gas turbine ignition to rated operation. 2... Combustor, 3... Gas turbine, 7... Exhaust heat recovery heat exchanger, 8... Steam turbine, 11... Steam flow rate control valve, 12... Steam manifold, 23...・・・
Steam piping, 24... Heater wire, 25... Power supply device.

Claims (1)

[Claims] A steam pipe for guiding steam extracted from a steam turbine or an exhaust heat recovery heat exchanger into a combustor, and a steam flow rate control valve installed in the steam pipe to adjust the flow rate of steam flowing in the steam pipe. A steam injection device for a gas turbine, which injects steam guided from the steam piping into a combustion flame in the combustor to reduce nitrogen oxides in turbine exhaust gas, wherein the downstream side of the steam flow rate control valve and the combustion 1. A steam injection device for a gas turbine, characterized in that a heater wire is disposed in a steam pipe between the steam pipe and the steam pipe, and the temperature of the steam pipe is adjusted by heating the heater wire.