KR20050017291A - An apparatus and method for the reduction of combustion oscillation on low NOx gas turbine combustor with duel combustion chamber - Google Patents

Abstract

PURPOSE: A combustion vibration reducing device of a low NOx gas turbine combustor with double chambers and a reducing method thereof are provided to prevent mechanical damage of the combustor and unstable operation by restricting combustion vibration in converting into the combustion mode or premixing fuel. CONSTITUTION: The total fuel(3) is supplied through a first fuel distribution valve(4) to a first stage combustion chamber(1) of a low NOx gas turbine combustor(100) as first fuel(5), and second fuel(6) is supplied through a second fuel distribution valve(7) to a second stage combustion chamber(2) as second premixing fuel and third fuel. A combustion vibration sensor(11) is installed in the combustor, and connected to an actuator(12). The actuator is connected and installed to the second fuel distribution valve, and a controller is installed between the actuator and the combustion vibration sensor. The actuator is connected to the controller and to the first fuel distribution valve.

Description

An apparatus and method for the reduction of combustion oscillation on low NOx gas turbine combustor with duel combustion chamber}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial gas turbine combustor, and more particularly, to an apparatus and method for reducing combustion vibration generated during switching of a combustion mode and reducing combustion vibration during premixed combustion in a low NOx type gas turbine composed of a dual combustion chamber. It is about.

As is well known, industrial gas turbine combustors generate combustion vibrations when a wave period of combustion heat generated during combustion is combined with an acoustic period when the combustion sound generated at this time is reflected back by the combustor liner. It is known.

In particular, in order to reduce thermal NOx of gas turbines, a low NOx type combustor with lean premixed combustion having a low equivalent ratio is employed to lower the combustion temperature. The combustion vibration is more likely to occur due to the absence or reduction of cooling air holes.

If the combustion vibration generated in the gas turbine combustor exceeds the limit value, the gas turbine hardware may be damaged and the safe operation may be inhibited.

Therefore, it is very important to reduce the combustion vibration generated in the combustor during gas turbine operation.

Meanwhile, in order to reduce NOx generated during combustion of a gas turbine, US Patent No. 4,292,801 has proposed a combustor having a dual combustion chamber and a dual combustion mode, and this US patent discloses a combustor having a single fuel nozzle. In comparison, NOx generation was significantly reduced. The combustor first forms a flame in the primary combustion chamber, and the fuel supplied to the primary combustion chamber is converted into a secondary fuel, which causes the flame in the primary combustion chamber to be turned off and a flame is formed in the secondary combustion chamber. . Subsequently, fuel is supplied to the primary combustion chamber again, premixed with air, and then ignited in the secondary combustion chamber to combust with the secondary fuel.

In addition, U.S. Patent No. 4,982,570 proposes that the secondary fuel nozzle in the secondary combustion chamber can have two types of double flames, a diffusion flame and a premix flame, so that the ratio of the fuel for the diffusion flame in the secondary combustion chamber NOx was further reduced by decreasing

However, the combustor composed of the dual combustion chamber has a high combustion dynamic pressure in the process of switching from the diffuse flame combustion of the primary combustion chamber to the premixed combustion mode of the secondary combustion chamber region. Was developed to supply fuel for diffusion flame to the secondary nozzle during the combustion mode change, and another US Patent No. 5,487,275 proposes a means for placing the diffusion fuel fuel from the nozzle during the combustion mode change. It was.

5 is a schematic diagram of a combustor and fuel supply system composed of a dual combustion chamber as described in the prior art US Pat. No. 5,487,275. 5, reference numeral 1 denotes a first stage combustion chamber, 2 a second stage combustion chamber, 3 a total fuel supplied to a gas turbine combustor, and 4 a fuel supplied to the first and second stage combustion chambers as a primary fuel distribution valve. The distribution ratio is adjusted, 5 is the first stage combustion chamber feed fuel, 6 is the secondary fuel supplied to the second stage combustion chamber, and 7 is the secondary fuel distribution valve. A valve for distributing fuel for diffusion flames, 8 is a secondary fuel (premixed fuel), 9 is a tertiary fuel (for diffusion oxide), used only when switching the combustion mode, and the total amount of primary fuel is changed when the combustion mode is switched. Converted to tertiary fuel, reference numeral 10 is a venturi neck that separates the first and second stage combustion chambers and serves to prevent the flames of the second stage combustion chamber from flashing back to the first stage chamber.

In this patent, at low loads, the fuel is combusted by supplying a primary fuel 5 (diffusion flame) and a secondary fuel 8 (for premixing), which are first stage combustion chamber feed fuels. When the output is increased, the combustion mode is changed to operate the premixed combustion in both the first and second stage combustion chambers for low NOx combustion. At this time, the primary fuel distribution valve 4 is operated to shut off the primary fuel 5 At the same time, the secondary fuel distribution valve 7 is operated so that the primary fuel 5 is converted into the tertiary fuel 9 in its entirety.

This turns off the flame of the primary combustion chamber and forms a third diffusion flame in the secondary combustion chamber, after which the primary fuel distribution valve is operated again to supply the primary fuel and then the secondary fuel distribution valve (7). Is activated to shut off the tertiary fuel (9).

The primary fuel is then premixed in the primary combustion zone to premix combustion with the secondary fuel in the secondary combustion chamber.

However, US Patent No. 5,487, 275 described above is difficult to smoothly convert the primary fuel into the tertiary fuel (for the diffusion salt) at once, and thus it is very difficult to effectively reduce the combustion vibration generated during the combustion mode conversion. As a result of analysis using Flowmaster, a flow analysis program for the conversion time, it was found that the reduction of fuel occurs as shown in FIG. 6, and that the combustion vibration in the gas turbine is increased as shown in FIG. 7. Was observed.

In addition, the conventional invention has a problem that there is no means to reduce the combustion when the combustion vibration is high during the pre-mix operation at a high output.

Therefore, the present invention effectively reduces the combustion vibration generated during the switching of the combustion mode in the conventional combustion system composed of the double combustion chamber, and reduces the combustion vibration when the combustion vibration is higher than the limit value while operating the premixed flame at high power. The purpose of the present invention is to provide a combustion vibration reduction device and a method for reducing the combustion of a low NOx gas turbine combustor composed of a dual combustion chamber.

In order to achieve the above object, in the present invention, in order to effectively suppress the rise of the combustion vibration occurring during the combustion mode switching in a combustion system having a combustor composed of a conventional double combustion chamber, the third fuel (diffusion) is immediately before the combustion mode switching. Means for supplying a part of the flame to smoothly convert the primary fuel of the first stage combustion chamber into the tertiary fuel during the combustion mode changeover, and detecting the combustion vibration during the combustion mode changeover to the combustion vibration when the combustion vibration rises. In addition to suppressing combustion vibrations by increasing proportionally stable tertiary fuels (diffusion oxides), combustion vibrations are also detected from combustion vibration sensors to reduce the combustion vibrations generated when the combustion system is premixed at high power. Control the fuel valve to supply stable tertiary fuel (extended salt), or it is equipped with a controller to It is adapted to generate heat.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The same reference numerals are used for the same parts as those of the conventional apparatus for better understanding of the present invention.

1 is a block diagram of a reduction apparatus for reducing combustion vibration in a low NOx combustor composed of a double combustion chamber according to the present invention.

According to the present invention, as shown in the drawing, the primary fuel 5 is supplied to the first stage combustion chamber 1 of the combustor 100 via the primary fuel distribution valve 4. The secondary fuel 6 is supplied to the secondary fuel 8 and the tertiary fuel 9 for premixing through the secondary fuel distribution valve 7 to the second stage combustion chamber 2 of the combustion chamber 100. In the low NOx type gas turbine combustor composed of a double combustion chamber, the secondary fuel distribution valve 7 is provided with an actuator 12 connected to the combustion vibration sensor 11 installed in the combustor 100.

In FIG. 1, reference numeral 1 denotes a first stage combustion chamber of the combustor 100, 2 a second stage combustion chamber, 3 a total fuel supplied to a gas turbine combustor, and 4 a first stage fuel distribution valve. It is a valve that controls the fuel distribution ratio supplied to the combustion chamber, 5 is the primary fuel supplied to the first stage combustion chamber, 6 is the secondary fuel supplied to the second stage combustion chamber, and 7 is the secondary fuel distribution valve. However, the valve controls the distribution ratio of the pre-mixed secondary fuel and the tertiary fuel (for the diffusion salt), 8 is the secondary fuel for the pre-mix, 9 is the tertiary fuel (for the diffusion salt), and 10 is the venturi neck. It separates the first stage and second stage combustion chambers and prevents the flame of the second stage combustion chamber from being backfired into the first stage chamber. Reference numeral 11 is a dynamic pressure sensor for measuring the combustion vibration instantaneously, the actuator 12 amplifies the signal received from the sensor to operate the fuel valve.

In addition, the present invention provides a first stage combustion chamber (1) and a second stage combustion chamber (2) based on the venturi neck (10) in order to reduce the combustion vibration occurring during the combustion mode conversion in the low NOx type gas turbine combustor composed of a dual combustion chamber. In the combustor 100 having a total fuel (3) through the primary combustion distribution valve (4), primary and secondary fuels (5, 6) and primary fuel (6) for supplying the primary combustion chamber. The actuator 12 drives the secondary fuel distribution valve 7 by being supplied to the secondary fuel 8 for mixing and the tertiary fuel 9 for diffusion flames and receiving a signal from the combustion vibration sensor 11. When switching the combustion mode by supplying 2% of the tertiary fuel 9 of the fuel supplied to the secondary combustion chamber 2 just before the mode change, and converting the primary fuel 5 into the stable tertiary fuel 9 smoothly. This is to reduce combustion vibration generated.

On the other hand, at low load, the fuel is combusted by supplying the primary fuel 5 (diffusion flame), which is the first stage combustion chamber supply fuel, and the secondary fuel 8 for mixing. When the power is increased, the combustion mode is changed to operate both the first and second stage combustion chambers 1 and 2 for premixed combustion for low NOx combustion. At this time, the primary fuel 5 supplied to the first stage combustion chamber is converted into the tertiary fuel 9 for the diffusion flame of the second stage combustion chamber 2, and the flame is turned off in the first stage combustion chamber 1. Afterwards, the tertiary fuel 9 is supplied to the primary fuel 5 and premixed in the first stage combustion chamber 1 to be combusted in the second stage combustion chamber 2.

That is, the method of the present invention is the same as the conventional invention, but in the present invention, the secondary fuel distribution valve 7 is operated immediately before the combustion mode is changed when the combustion system is switched to the combustion fuel. By opening in advance and pushing the air filled in this tertiary fuel supply pipe and prefilling it with fuel, the primary fuel smoothly switches to the tertiary fuel 9 when the combustion mode is switched to reduce the combustion vibration.

As another means for reducing combustion vibration during combustion mode switching, when the combustion vibration is increased during the combustion mode switching in FIG. 1, the combustion vibration sensor 11 detects the combustion vibration and sends the signal to the actuator 12. The actuator amplifies the combustion vibration signal to drive the secondary fuel distribution valve 7 to increase the stable third fuel 9 in proportion to the combustion vibration magnitude to reduce the combustion vibration.

On the other hand, when the combustion system composed of the dual combustion chambers performs premixed combustion operation at high power, combustion vibrations due to combustion instability are likely to occur due to changes in fuel or air and other combustion conditions.

Accordingly, the present invention provides a means for suppressing the combustion vibration generated during the premixed combustion at high output of the combustion system as described above. For example, in the combustion system as shown in FIG. If the combustion vibration is increased during the combustion vibration, combustion vibration generated from the combustor is sensed by the combustion vibration sensor 11 and the signal is sent to the actuator 12. The actuator amplifies the combustion vibration signal to drive the secondary fuel distribution valve 7. Thus, the stable third fuel 9 is increased in proportion to the size of the combustion vibration, thereby reducing the combustion vibration.

On the other hand, as another embodiment for suppressing the combustion vibration generated during the premixed combustion operation at high power in the combustion system, the apparatus as shown in FIG. 2 has been proposed, which measures the combustion vibration in real time during the premixed combustion. The combustion vibration sensor 11, the controller 13 which produces | generates the signal which is reverse phase with a combustion vibration signal, and the actuator 12 which drives a secondary fuel distribution valve are provided. In this embodiment, when the combustion vibration sensor 11 detects an increase in the combustion vibration, this signal is transmitted to the controller 13, and the controller 13 generates a signal that is reversed in this combustion vibration. To the actuator 12. The actuator 12 then receives this signal to operate the valve of the tertiary fuel 9 to generate combustion heat that is reversed to the combustion vibration in the combustor.

The concept of suppressing combustion vibration by generating reverse heat of combustion in combustion vibration is based on the well-known Rayleigh standard. In other words, Equation (1) to be described later represents the Rayleigh criterion, and when the left side composed of the pressure on the left side and the heat release term is greater than the acoustic losses on the right side, the energy generating combustion vibration is amplified, and the heat emission variation on the left side. ( ) Is in phase with the acoustic pressure fluctuation (P '), the combustion vibration tends to be amplified; on the contrary, if the heat emission fluctuations are in phase with the pressure fluctuation, the combustion vibration tends to be attenuated.

4 is a graphical representation of this.

3, which is another embodiment of suppressing combustion vibration during premixed combustion, when the combustion vibration is increased from the combustion vibration sensor 11 in the embodiment of FIG. 2, the signal is transmitted to the controller 13. The controller 13 changes the phase of this combustion vibration and applies a signal to the actuator 12. Then, the actuator 12 receives this signal and drives the primary fuel distribution valve 4 to drive the primary and secondary valves. By adjusting the fuel distribution ratio, the primary and secondary heat generation amounts are adjusted, and the combustion vibration generation is reduced by preventing the combustion heat generation amount from becoming in phase with the combustion vibration.

The present invention has the effect of suppressing the combustion vibration generated during the combustion mode conversion compared to the conventional low NOx type combustor composed of a double combustion chamber.

In addition, by suppressing the rapid rise of combustion vibration during premixed combustion at high power, the combustion system can obtain the effect of eliminating unstable operation due to mechanical damage or fluctuation of output of the combustor.

1 is a block diagram of an apparatus for reducing combustion vibration in a low NOx combustor composed of a double combustion chamber according to the present invention;

2 is a block diagram showing another embodiment of the present invention,

3 is a block diagram showing another embodiment of the present invention,

4 is a combustion vibration change graph according to the phase of pressure and heat release amount;

5 is a block diagram of an apparatus for reducing combustion vibration in a low NOx combustor composed of a conventional double combustion chamber,

6 is a fuel flow rate analysis graph during combustion mode conversion in FIG.

7 is a graph showing a combustion distribution valve opening and combustion vibration change in FIG.

-Explanation of symbols for the main parts of the drawings-

1: 1 stage combustion chamber, 2: 2 stage combustion chamber,

3: total fuel, 4: primary fuel distribution valve,

5: primary fuel, 6: secondary fuel,

7: secondary fuel distribution valve, 8: secondary fuel for premixing,

9: tertiary fuel, 10: venturi neck,

11: combustion vibration sensor, 12: actuator,

13: controller.

Claims (8)

The total fuel 3 is supplied to the first stage combustion chamber 1 of the combustor 100 via the primary fuel distribution valve 4 and the primary fuel 5 is supplied to the second stage combustion chamber 2 of the combustor 100. Low NOx gas consisting of a dual combustion chamber in which the secondary fuel (6) is supplied to the premixed secondary fuel (8) and the tertiary fuel (9) via the secondary fuel distribution valve (7) and combusted. In a turbine combustor, Combustion of a low NOx gas turbine combustor composed of a double combustion chamber, characterized in that the secondary fuel distribution valve 7 is connected to the actuator 12 connected to the combustion vibration sensor 11 installed in the combustor 100. Vibration reduction device. 2. The apparatus for reducing combustion vibration of a low NOx gas turbine combustor as claimed in claim 1, wherein a controller (13) is provided between the actuator (12) and the combustion vibration sensor (11). 3. Apparatus according to claim 2, characterized in that the actuator (12) connected to the controller (13) is connected to the primary fuel distribution valve (4). Combustor equipped with a first stage combustion chamber (1) and a second stage combustion chamber (2) based on the venturi neck (10) to reduce the combustion vibration occurring during the combustion mode change in the low NOx type gas turbine combustor composed of a dual combustion chamber. The secondary fuel (5) and the secondary fuel (6) for premixing the secondary fuel (6) and the secondary fuel (6) for supplying the primary combustion chamber through the primary combustion distribution valve (4). Supplied to the fuel 8 and the tertiary fuel 9 for diffusion flames and receives a signal from the combustion vibration sensor 11, the actuator 12 drives the secondary fuel distribution valve 7, immediately before switching to the combustion mode. Combustion vibration generated when the combustion mode is switched by supplying 2% of the tertiary fuel 9 of the fuel supplied to the secondary combustion chamber 2 in advance and converting the primary fuel 5 into the stable tertiary fuel 9 smoothly. Combustion vibration reduction method of a low NOx gas turbine combustor composed of a combustion chamber configured to reduce the. The combustion vibration sensor 11 detects combustion vibration from the combustion vibration sensor 11, amplifies the combustion vibration signal in the actuator 12, and drives the secondary fuel distribution valve 7. A method for reducing combustion vibration of a low NOx gas turbine combustor, characterized in that it is provided to supply a stable tertiary fuel (9) in proportion to the combustion vibration. According to claim 4, If the combustion vibration of the combustor during the high power premixed combustion in the combustor 100, the combustion vibration is detected by the combustion vibration sensor 11, the actuator 12 is a combustion vibration sensor ( 11) amplification of the signal received from the secondary fuel distribution valve (7) to increase the stable third fuel (9) in proportion to the size of the combustion vibration reduced combustion vibration of the low NOx gas turbine combustor, characterized in that Way. 5. The signal according to claim 4, wherein if the combustion vibration is increased from the combustion vibration sensor (11) during the premixed combustion operation of the combustor (100), this signal is transmitted to the controller (13) and the combustion vibration is generated in the controller (13). The fuel for diffusion flames is generated so as to generate a signal in reverse phase to the actuator 12 and transmit the signal to the actuator 12 in order to generate the heat of combustion reverse to the combustion vibration in response to the signal. Combustion vibration reduction method of a low NOx gas turbine combustor, characterized in that configured to supply periodically. 5. The method according to claim 4, wherein if the combustion vibration is increased from the combustion vibration sensor (11), this signal is transmitted to the controller (13) and the controller generates a signal that is different from the phase of the combustion vibration signal to generate an actuator (12). The actuator 12 drives the primary fuel distribution valve 4 to adjust the primary and secondary fuel distribution ratios so as to change the amount of primary and secondary combustion heat generated so that the combustion heat is in phase with the combustion vibration generated in the combustor. A method of reducing combustion vibration of a low NOx gas turbine combustor, characterized in that it is controlled so as not to be in phase.