KR100716889B1 - A fuel nozzle with variable injection location of a dry low nox gas turbine combustor for power generation - Google Patents

Abstract

The present invention relates to a variable position fuel nozzle for a dry type low nitrogen oxide gas turbine combustor for power generation, and more particularly, to a variable low fuel nozzle for a low pressure nitrogen oxide gas turbine combustor for use in a dry low nitrogen oxide gas turbine combustor employing a lean- A fuel nozzle comprising: a pilot fuel injector for injecting fuel injected through a pilot fuel injection port through a hollow internal area and injecting fuel through a fuel injection part located at a front end; And a plurality of vanes annularly disposed around the pilot fuel injector and spaced apart from each other. The combustion air provided through the space between the vanes is discharged through the space between the vanes, causing swirl flow, And a swirler which is mixed with a main fuel injected through a main fuel injection hole formed in the vane, wherein the pilot fuel injector is formed so as to be axially movable with respect to the swirler so that the injection position of the combustion air and the main fuel The injecting position of the pilot fuel can be adjusted so that the pre-mixing distance of the air-fuel can be adjusted.

Injection position, fuel nozzle

Description

Technical Field [0001] The present invention relates to a low-NOx gas turbine combustor,

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cutaway longitudinal sectional view showing the configuration of a variable injection fuel nozzle according to an embodiment of the present invention; FIG.

2 is a sectional view showing another example of a hydraulic mechanism in the injection position variable fuel nozzle shown in Fig.

Fig. 3 is a front view seen from the direction (A) of Fig. 1; Fig.

4 is a perspective view showing a part of a vane installed in the upper and lower swing machines in the embodiment of the present invention.

5 illustrates a multi-cup combustor liner with an injection position variable fuel nozzle according to an embodiment of the present invention.

The present invention relates to a fuel nozzle for variable injection position of a dry type low nitrogen oxide gas turbine combustor for power generation, and more particularly, to a fuel nozzle for variable nozzle of a low-NOx gas turbine combustor for power generation, The present invention relates to a fuel nozzle with variable injection position of a dry low NOx gas turbine combustor capable of controlling the fuel-air premixing distance in a dry low NOx gas turbine combustor of a premixed combustion unit.

In the case of a lean premixed combustion gas turbine, a dry low NOx burner is adopted to suppress the generation of nitrogen oxides (NOx) by lowering the flame temperature. However, in order to suppress the generation of nitrogen oxides, since the flame temperature must be lowered by burning in a fuel-air mixture ratio range where the fuel equivalence ratio is low, combustion is unstable, and combustion vibration and flame backlash occur frequently.

Also, in the lean premixed combustion method, since the mass ratio of the fuel amount is less than 10% as compared with the air amount, the control of the fuel amount is very important and it is very difficult to reach the stable combustion condition. In addition, gas turbine parts are damaged due to unstable combustion, combustion vibration, flame backlash due to unburned combustion and large pressure fluctuations caused by fuel-air mixture and load conditions, and heat loss and shortening of life of parts due to high temperature flow Resulting in an increase in the maintenance cost of the gas turbine.

Conventionally, when a gas turbine is operated at a low load, noxious gases such as yellow plume caused by NO ₂ are discharged according to the combustion state, thereby causing a complaint from the residents near the power plant.

Conventional gas turbine combustors actively control the load by regulating the flow rate of fuel and air in accordance with the combustion mode and promote radial vortex flow through the swirler to promote the mixing of fuel and air, The stability of the product. However, since the position of the fuel injection port is fixed throughout the entire combustion mode, the flash back and the fuel-air mixture (fuel mixture) are increased with the increase of the burning velocity when the fuel amount is increased according to the load. The unstable combustion due to the nonuniform distribution in time and space of the exhaust gas, and the increase of the harmful exhaust gas.

Premixed combustion is characterized in that the generation of combustion vibration and nitrogen oxide is sensitively changed according to the distance from the position of the fuel injection hole injected to the combustion air side to the flame zone, that is, the fuel-air mixing length Has been known from many studies (T. Lieuwen, DA Santavicca, JG Lee et al.). However, current gas turbine power plants only control the fuel and air flow rate according to the operation mode from the start of the power plant to the full load.

In particular, the fuels used in the combined cycle thermal power plant are natural gas (CH ₄ ), which accounts for the majority of the fuels, and the clean new DME (DM Ether, CH ₃ OCH ₃ ) This fuel will be applied after the evaluation of the technology, and it has a high burning velocity and a low ignition temperature combustion characteristic, which may cause burner burnout due to flame backfire. Therefore, further control of the fuel-air mixing distance becomes necessary.

Korean Patent No. 10-0446884-0000 is known as a prior art related to a dry low-NOx gas turbine combustor for power generation. However, it is impossible to adjust the mixture distance of the fuel and the air by adjusting the position of the fuel injection port by changing the swirl intensity by controlling the swirler in the power generation gas turbine.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a fuel low-NOx gas turbine, The injection position of the dry low-NOx gas turbine combustor for power generation is adjusted so that the mixing degree, which is an important parameter for the combustion, can be controlled by adjusting the injecting position of the pilot fuel according to the mode conversion, The present invention has been made to provide a fuel nozzle.

Further, in addition to the position control of the pilot fuel injector, the present invention enables the flow rate control of the pilot fuel injected from the pilot fuel injector and the main fuel injected from the upper and lower revolvers so that the combustion is optimally performed inside the combustor The present invention is directed to a fuel nozzle having a variable injection position of a dry low-NOx gas turbine combustor for power generation.

The present invention also relates to a method and apparatus for controlling the injection position variable fuel nozzle of a dry low-NOx gas turbine combustor for power generation, which can be applied to the combustion of various fuels without replacing the fuel nozzle according to the replacement of the fuel in the dry low- There are other aims to provide.

In order to achieve the above object, the present invention provides a variable-nozzle fuel injection nozzle of a dry low-NOx gas turbine combustor for power generation of a dry low-NOx gas turbine combustor employing a lean-premixed system, Is injected through a fuel injecting portion located at the front end, the pilot fuel injecting body moving through a hollow inner region of the pilot fuel injecting body; And a plurality of vanes annularly disposed around the pilot fuel injector and spaced apart from each other. The combustion air provided through the space between the vanes is discharged through the space between the vanes, causing swirl flow, And a swirler which is mixed with a main fuel injected through a main fuel injection hole formed in the vane, wherein the pilot fuel injector is formed so as to be axially movable with respect to the swirler so that the injection position of the combustion air and the main fuel The injecting position of the pilot fuel can be adjusted so that the pre-mixing distance of the air-fuel can be adjusted.

According to the present invention, there is also provided a hydraulic device for supporting a lower portion of the pilot fuel injector and moving the pilot fuel injector in an axial direction while a supply oil flow rate is determined by a control signal, An annular oil tube body surrounding a lower portion of the pilot fuel injector; A piston head attached to a lower end portion of the pilot fuel injector and moving up and down in a state of supporting the pilot fuel injector by an oil pressure determined according to an amount of oil supplied into the oil valve body; And a restoration spring for supporting the lower portion of the pilot fuel injection body in a direction opposite to the hydraulic force acting direction.

According to the present invention, the swirler includes upper and lower swirlers, and a control valve for controlling the flow rate is provided on the fuel supply path through which the main fuel is supplied to the upper and lower swirlers, respectively. So that the flow rate of the main fuel injected from the fuel pump can be adjusted. This allows the selection of a swirler to which the main fuel is injected or freely adjusts the injection ratio of the main fuel injected through the upper and lower swirlers.

According to the present invention, the plurality of injecting position variable fuel nozzles are provided to constitute a multi-cup combustor liner, wherein the pilot fuel injectors of each fuel nozzle constituting the multi-cup combustor are independent of each other So that the injection position is determined.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in more detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cross-sectional view showing the construction of a variable injection fuel nozzle of a dry low nitrogen oxide gas turbine combustor according to an embodiment of the present invention; FIG.

Referring to the drawings, an embodiment of an injection position variable fuel nozzle 100 of a dry low NOx gas turbine combustor for power generation according to an embodiment of the present invention includes a pilot fuel injector 110.

The pilot fuel injector 110 is formed of a hollow cylindrical body and the inner region is a path through which the pilot fuel injected through the pilot fuel injection port 101 located at the lower end flows toward the fuel injector 112. A control valve 101a is provided on a path for supplying fuel to the fuel injection port 101 so that the flow rate of the pilot fuel is adjustable.

The pilot fuel injector 110 is installed so as to be vertically movable in the axial direction. The fuel injector 112 disposed at the end of the pilot fuel injector 110 is provided with a central fuel injection hole 114 positioned at the center and ten outer fuel injectors 114 formed around the central fuel injection hole 114, 116 are formed. The hole diameter of the central fuel injection hole 114 is formed larger than the diameter of the outer fuel injection hole 116.

The pilot fuel injected through the fuel injecting portion 112 is injected from the downstream side of the main fuel injected through the main fuel injection holes 213 and 223 located in the swivel and the injection position of the pilot fuel with respect to the injection position of the combustion air and the main fuel is Determine the pre-mixing distance of the fuel-air and the length of the diffusion flame.

The pilot fuel injector 110 is configured to be capable of adjusting the injecting position of the fuel while moving up and down in the axial direction by the hydraulic mechanism 120.

The lower portion of the pilot fuel injector 110 is located inside the combustor casing 105 and has a flange portion 111 extending in the radial direction. The flange portion 111 under the pilot fuel injector 110 is located inside the annular oil tube body 124 so as to be translationally moved up and down by the hydraulic mechanism 120 and the flange portion 111 is provided with an annular piston head (Not shown). Further, a force pushing the flange portion 111 downward is applied by the amount of oil supplied to the inside of the oil tube member 124 of the piston head 126, that is, the oil pressure. A restoring spring 128 is attached to the oil tube member 124 so that the piston head 126 and the flange portion 111 attached thereto are pulled upward when the oil pressure decreases. Thus, as the pressure in the oil tube member 124 increases, the pilot fuel injector 110 moves down with the piston head 126 and moves in the opposite direction by the restoring spring 128 when the pressure is reduced.

Another example of a hydraulic mechanism for translating the pilot fuel injection body 110 in the axial direction is shown in Fig. The piston head 136 attached to the flange portion 111 of the pilot fuel injector 110 receives the movement of the piston 134 moving upward and downward within the cylinder 132 through the rod 135, So that the pilot fuel injector 110 is vertically translated in the axial direction. At this time, a restoring spring 128 surrounding the piston rod 136 exerts a force to push up the pilot fuel injector 110 when the hydraulic pressure decreases.

A revolving machine 200 constituted by upper and lower revolving machines 210 and 220 is installed to surround the pilot fuel injecting body 110. FIG. 3 is a view showing the upper swinging machine, and FIG. 4 is a perspective view showing two vanes in the upper swinging machine.

Referring to the drawing, the swirler 200 surrounds the pilot fuel injector 110, and two swirlers are installed as the upper swirler 210 and the lower swirler 220. The pilot fuel injecting body 110 is configured to translate the pilot fuel injecting body 110 in the axial direction with respect to the swirler 200.

The upper and lower swivel units 210 and 220 are provided with ten vanes 212 and 222 spaced from each other while both ends are supported by the inner and outer cylindrical structures 211a and 211b. In each of the vanes 212 and 222, five main fuel injection openings 213 and 223 are formed in such a manner that the diameter gradually increases in the radial direction. Fuel inlets 214 and 224 are formed on the sides of the vanes 212 and 222 and connected to the main fuel injection ports 216 and 226 through pipes. Control valves 216a and 226a are provided on the paths through which the main fuel is supplied to the main fuel injection ports 216 and 226, respectively, so that the flow rate of the main fuel is independently controllable.

The combustion air supplied through the combustion air inlet 230 is supplied to the outer periphery of the pilot fuel injector 110 and passes through the vortexes 212 and 222 of the upper and lower swingers 210 and 220 To the outside of the pilot fuel injector 110. [ Since the vanes 212 and 222 are inclined at an angle of 30 ° or 45 ° or 60 ° relative to the horizontal plane, the combustion air supplied through the combustion air inlet 230 flows through the swirler 200, ).

The main fuel which is supplied through the main fuel inlets 214 and 224 and injected through the main fuel injection openings 213 and 223 is supplied to the lower turnaround fuel inlet 226 and the upper turnaround fuel inlet 216 respectively, The control valves 216a and 226a are controlled by the control signals and are independently controlled. The main fuel (natural gas or DME) that is discharged through the main fuel injection ports 213 and 223 of each of the vanes 212 and 222 is injected into the combustion chamber while being mixed with the combustion air in the swirl flow state, (Turbulent Flame Propagation Speed = Convection Velocity of Mixture) corresponding to the combustion conditions by the injection position of the pilot fuel injected through the flame 112.

Meanwhile, the change in the flow rate of the main fuel supplied from the upper and lower swirlers also affects the shape of the flame and the premixed combustion characteristics. When the power plant starts and low loads, the main fuel is supplied through the upper swirler, The mixing distance can be lengthened by controlling the main fuel to be supplied in the lower swivel.

That is, it is possible to control the injection position of the pilot fuel according to the axial movement of the pilot fuel injector, to control the injection flow rate, to control the mixing distance and mixing degree by controlling the flow rate of the main fuel injected from the upper and lower revolvers, By changing the characteristics, it becomes possible to achieve the object of reducing combustion vibration, reducing harmful exhaust gas, increasing combustion stability, and increasing combustor performance and efficiency.

Figure 5 is a view of a multi-cup combustor liner with injection position variable fuel nozzles in accordance with an embodiment of the present invention.

The multi-cup combustor liner 10 of the dry low-NOx gas turbine combustor has one central injection-position variable fuel nozzle 100-1 and five outer-injection-position variable fuel nozzles 100-2 surrounding the variable fuel nozzle 100-1. Each pilot fuel injector 110 of each of the fuel nozzles 100-1 and 100-2 constituting the multi-cup combustor liner is configured to be able to independently translate upward and downward in the axial direction by a control signal with respect to the swirler 200 have. That is, the mixing distances in the respective nozzles are individually controlled. The fuel flow rate in the multi-cup combustor liner 10 is controlled separately for each nozzle for stable combustion and uniform thermal distribution within the entire combustor. This can be largely used to improve the combustion stability, reduce the combustion vibration and reduce the emission concentration of the harmful exhaust gas.

According to the present invention, it is possible to control an appropriate fuel injection quantity and injection position required for each combustion mode and load in a gas turbine for power generation using natural gas or DME as fuel, thereby improving the combustion efficiency, It is possible not only to reduce combustion instability while reducing gas, but also to prevent flame backlash and to prevent heat burnout of high-temperature flow path components in the gas turbine.

Further, according to the present invention, in a low-NOx gas turbine combustor for power generation using a lean premix combustion system by setting an appropriate fuel injection timing, injection position and flow rate for each fuel nozzle in a plurality of multi-cup combustor liners, It is possible to stabilize the entire internal flame, prevent backfire and reduce combustion vibration, thereby preventing damage to parts of the gas turbine and prolonging its service life.

In particular, DME (DiMethyl Ether, CH ₃ OCH ₃ ), which is being actively studied at home and abroad, is used for the natural gas used in power generation gas turbines and the basic physical properties such as molecular weight, diffusion coefficient and calorific value, ) And self ignition temperature (combustion temperature). Therefore, it can not be applied to existing gas turbine combustors. According to the present invention, however, it is possible to adjust the injecting position of the pilot fuel through the fuel injector while the pilot fuel injector moves up and down in the axial direction, so that the flow rate of the main fuel injected from the upper and lower revolvers is controlled through the control valve, All of the branch fuel can be stably burned.

Claims (5)

An injection position variable fuel nozzle (100) for a dry low NOx gas turbine combustor for power generation of a dry low NOx gas turbine combustor employing a lean premixing method, A pilot fuel injecting body 110 through which the fuel supplied through the pilot fuel injecting port 101 moves through the hollow inner region and is injected through the fuel injecting portion 112 located at the front end; And And a plurality of vanes 212 and 222 arranged around the pilot fuel injector 110 and annularly spaced from each other so as to be provided through the space between the vanes 212 and 222, The swirling flow 107 is generated while the combustion air is discharged and the swirler 200 is mixed with the main fuel injected through the main fuel injection holes 213 and 223 formed in the vanes 212 and 222, The pilot fuel injector 110 is formed so as to be axially movable with respect to the swirler 200 so that the injection position of the pilot fuel can be adjusted with respect to the injection position of the combustion air and the main fuel. Variable fuel nozzle for the injection position of a dry low nitrogen oxide gas turbine combustor. The method according to claim 1, And a hydraulic mechanism (120) for supporting the lower portion of the pilot fuel injector (110) and moving the pilot fuel injector (110) up and down in the axial direction while a supply oil flow rate is determined by a control signal Variable fuel nozzle for injection position of dry low NOx gas turbine combustor for power generation. 3. The hydraulic system according to claim 2, wherein the hydraulic mechanism (120) An annular oil tube body 124 surrounding the lower portion of the pilot fuel injector 110; A piston head 126 attached to a lower end portion of the pilot fuel injecting body 110 and moving up and down in a state of supporting the pilot fuel injecting body by hydraulic pressure determined according to the amount of oil supplied into the oil tub body; And And a restoring spring (128) for supporting the lower portion of the pilot fuel injecting body (110) in a direction opposite to a hydraulic force acting direction of the pilot fuel injecting body (110). The method according to claim 1, The pivoting device 200 includes upper and lower pivoting devices 210 and 220, Control valves 216a and 226a for controlling the flow rate are provided on the fuel supply path through which the main fuel is supplied to each of the upper and lower revolvers 210 and 220 so that the main fuel injected from each of the upper and lower revolvers 210 and 220 Wherein the flow rate of the fuel is adjustable. 5. The method according to any one of claims 1 to 4, A plurality of injection position variable fuel nozzles 100-1 and 100-2 are installed to constitute a multi-cup combustor liner 10, The pilot fuel injectors 100 of the fuel nozzles 100-1 and 100-2 constituting the multi-cup combustor 10 independently move up and down relative to the revolvers 200 of the respective fuel nozzles, Wherein the gas turbine combustor is configured such that the gas turbine combustor is configured such that the gas turbine combustor is disposed in the combustion chamber.

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