JP7270111B2 - Combustion equipment that maximizes combustor operating efficiency and emissions performance - Google Patents

Description

The present invention is a combustion apparatus capable of maximizing the operating efficiency and emissions performance of the combustor, and more particularly, through improvement of the dual channel system, a high temperature inner recirculation zone is provided within the combustion field. turbulence intensity is enhanced, and during combustion, the residence time of hot combustion products in the flame is shortened, such as nitrogen oxides, etc., which are sensitive to the residence time of combustion products. However, even if the load changes, especially the flash-back that can occur at low loads, the turbulence generation part with enhanced turbulence intensity is structurally Combustor turbulence that can increase the operating efficiency of the combustor and maximize the operating efficiency and emissions performance of the combustor by minimizing the total system outage of the combustor due to failure of vulnerable parts of the combustor. It relates to a flow generating grid structure.

Nitrogen oxides (NOx) are compounds of nitrogen and oxygen and refer to NO, NO2, NO3, N20, N2O3, N2O4, and N2O5. Among these, NO and NO2 are classified as the most serious air pollutants because they are emitted in large amounts when combustion air is used to burn fossil fuels. NOx is a generic term for all nitrogen oxides, but in the air pollution field it generally means NO and NO2. Nitrogen oxides are mainly emitted during the combustion process of fossil fuels. During combustion, nitrogen oxides are emitted into the atmosphere in a gaseous state and then condensed by photochemical reactions. It is known to be the main culprit of condensed dust (CPM), which is converted into particulate matter (PM2.5), and has recently been added as a pollutant subject to air emission levies by the government. Microparticulate matter has a diameter of about 2.5 μm, which is 1/30 the diameter of a human hair, unlike general particulate matter (PM10), which has a diameter of about 10 μm. Unfiltered, it penetrates into the lungs and blood vessels, causing angina pectoris, stroke, and cardiovascular disease.

Emissions standards for nitrogen oxides are mostly based on numerical values that assume that NO is oxidized to NO2, but NOx, the nitrogen oxides that are inevitably produced when burning fossil fuels, is a condensable dust. It is known as a precursor of nitrate, which is a kind of nitrate, and after being generated in a gaseous state from a combustion device and released into the atmosphere, it is condensed by a photochemical smog reaction with water vapor, ozone, ammonia, etc., and becomes a solid particulate form. It is a representative atmospheric environmental pollutant that develops into substances. Therefore, it can be said that a method for reducing the amount of harmful substances generated during combustion, such as nitrogen oxides, is extremely important.

By way of example, US Pat. No. 5,900,000 discloses a technique for controlling the reduction of nitrogen oxides in a flue gas stream. Considering the technical characteristics of the control method for the reduction of nitrogen oxides in the flue gas stream, the nitrogen oxides are removed by stepwise nitrogen-containing treatment formulations or selective catalytic reduction (SCR). However, the harmful gas generated after combustion has to be moved to a separate device, and there are disadvantages such as the need for a separate treatment material for nitrogen oxide treatment. It is a device related to post-treatment, and there was a problem that nitrogen oxides could not be fundamentally reduced in the combustion process.

In addition, in Patent Document 2, in addition to swirling the mixed flow of gas fuel and air, by generating turbulence with a turbulent plate arranged downstream of the fuel nozzle, the mixing distance of the mixed flow is reduced, Features are disclosed that prevent backflow, bonfires, and the development of hot zones. However, the prior art has the problem that the structure that generates the turbulent flow is formed of a thin plate, and its strength is extremely weak. As an example, during operation of the combustor, load fluctuations result in significant changes in combustor flow, especially at low loads and low gas-fuel-air mixture velocities, causing the flame to enter the injection nozzle. A flash-back occurs that burns into the nozzle, and the flame adheres to the nozzle, damaging or destroying important parts of the combustor nozzle such as the turbulence plate and swirler, and affecting the entire system of the combustion device. A fatal loss that stops the operation will occur. In such a configuration of the plate-shaped turbulence generator, if a fire occurs, there is a concern that the nozzle may be thermally damaged. Even without a fire, continuous operation for a long period of time causes serious damage due to radiant heat from high-temperature flames, etc. Therefore, continuous replacement is required after a certain period of time. There was a problem.

Korean Patent No. 10-0016168 (1997.02.06.) Japanese Patent Laid-Open No. 09-170716 (1997.06.30.)

The present invention has been made to solve the problems of the prior art described above, and the amount of harmful gas generated during combustion is reduced by complete combustion of the combustion device in the combustion process, not by post-combustion treatment technology. The goal is to reduce and maximize the efficiency of the combustion system.

The present invention also minimizes burn-out of the combustion system due to load changes, especially the bonfire phenomenon that can occur at low loads, to increase operating efficiency and improve durability and reliability of the combustion system. Intended to maximize safety. As an example, in the case of a gas turbine combustor for power generation and aviation, in a turbine, which is a rotating body rotating at a high speed of several hundred thousand RPM (revolution per minute) at the rear end of the combustor, from the combustor nozzle An object of the present invention is to prevent extremely small broken fragments from fatally damaging the entire system of the gas turbine, just like a bird strike on an aircraft engine.

In addition, the present invention increases the strength of turbulence through a fractal turbulence generator in order to maintain a structurally sound fractal turbulence generator, thereby achieving a turbulent flame stabilizing function. (flame stabilizing) is enhanced, the occurrence of inner recirculation zone in the flame field due to low swirling flow is suppressed, the residence time of high temperature combustion products is shortened, and combustion such as nitrogen oxides is reduced. The purpose is to effectively suppress the generation of harmful substances.

In addition, the present invention improves the premixing performance of gas fuel through the double swirl structure and the cross flow structure because the harmful gas of nitrogen oxides depends on the mixing performance between air and fuel before combustion. for the purpose.

The problem to be solved by the present invention is not limited to the problems described above, and other problems to be solved by the present invention, which are not mentioned here, can be found in the technical field to which the present invention belongs from the following description. It will be clearly understood by those of ordinary skill.

In a combustion apparatus capable of maximizing the operating efficiency and emission performance of a combustor according to a preferred embodiment of the present invention, a gas nozzle section to which gas fuel is supplied; and a space communicating with the gas nozzle section to form a gas fuel. a first mixing chamber that communicates with the gas fuel distribution portion through a first through hole to form a space in which the gas fuel is premixed with air; and the gas fuel distribution portion and a second through hole. a second mixing chamber communicating through holes to form a space in which gaseous fuel is premixed with air; a turbulent flow generating nozzle section that turbulates the premixture of gas fuel and air; and a swirling nozzle section that communicates with the air nozzle section and supplies combustion air to the first mixing chamber and the second mixing chamber, respectively. , wherein the swirl nozzle part communicates with the first mixing chamber, and the gaseous fuel injected from the first through hole is in vertical contact with and mixed with the swirled air. The second passage communicates with the second mixing chamber so that the gaseous fuel injected from the second through hole is in vertical contact with air having a lower degree of swirl than the first passage and is mixed. 2 flow passages, wherein the turbulent flow generating nozzle section is provided with a plurality of fractal grid holes to generate a turbulent flow of the premixed gas fuel and air premixed in the first mixing chamber. and a cylindrical inner nozzle portion for causing the premixture of gaseous fuel and air that has passed through the turbulence generator to flow into the combustion chamber, the turbulence generator is formed long along the longitudinal direction of the inner nozzle part, and maintains the rigidity of the material structurally even if the flame adheres due to the bonfire phenomenon, so that the grid is not damaged and continuous combustion operation is possible. to increase system safety and combustion efficiency of the combustor.

By means of the solution to the above problems, the combustor according to the present invention is capable of maximizing the operating efficiency and emissions performance of the combustor so that changes in load, especially the bonfire phenomenon that can occur at low loads, will cause the combustor to stop operating. is minimized, the safety of the entire system of the combustion device can be ensured, and the efficiency of the combustion device can be maximized.

In addition, due to the fractal-like turbulence generation part and the structure of the low swirl blade, the formation of the internal recirculation area in the combustion device is suppressed, and the combustion temperature is high like thermal NOx (nitrogen oxide) during combustion. This has the effect of reducing the amount of harmful gas generated, which is closely related to the residence time of the product.

In addition, since nitrogen oxides are closely related to the mixing performance of fuel and combustion air, the mixing structure maintains a double swirl structure, a cross flow structure, and a fractal turbulent flow structure. , which can improve the premixing performance of premixture of gas fuel and air.

1 is a cross-sectional view showing a combustion device capable of maximizing operation efficiency and emission performance of a combustor according to a first embodiment of the present invention; FIG. FIG. 2 illustrates an embodiment of a turbulence generator of a combustion device that can maximize the operating efficiency and emissions performance of a combustor according to the first embodiment of the present invention; FIG. 4 is a diagram illustrating another embodiment of a turbulence generator of a combustion device capable of maximizing the operating efficiency and emission performance of the combustor according to the first embodiment of the present invention; FIG. 5 is a diagram illustrating yet another embodiment of a turbulence generator of a combustion device capable of maximizing the operating efficiency and emissions performance of a combustor according to the first embodiment of the present invention; FIG. 4 is a diagram illustrating the premixing behavior of a combustion device that can maximize the operating efficiency and emissions performance of a combustor according to a first embodiment of the present invention; FIG. 4 is a diagram illustrating the premixing behavior of a combustion device that can maximize the operating efficiency and emissions performance of a combustor according to a first embodiment of the present invention; FIG. 4 is a diagram illustrating the premixing behavior of a combustion device that can maximize the operating efficiency and emissions performance of a combustor according to a first embodiment of the present invention; FIG. 4 is a graph showing operational performance test results of a combustion device capable of maximizing operational efficiency and emission performance of a combustor according to the first embodiment of the present invention; FIG. 4 is a graph showing the measurement results of the amount of pollutants generated by the combustion apparatus that can maximize the operating efficiency and emission performance of the combustor according to the first embodiment of the present invention; FIG. 5 is a diagram illustrating a turbulence generator of a combustion device capable of maximizing the operating efficiency and emission performance of a combustor according to a second embodiment of the present invention; FIG. 7 is a diagram illustrating a turbulence generator of a combustion device that can maximize the operating efficiency and emission performance of a combustor according to a third embodiment of the present invention; FIG. 7 is a diagram illustrating a turbulence generator of a combustion device that can maximize the operating efficiency and emission performance of a combustor according to a fourth embodiment of the present invention;

The terms used in this specification will be briefly explained, and the present invention will be specifically explained.

The terms used in the present invention were selected as general terms that are currently widely used as much as possible in consideration of the function in the present invention. It may change due to the advent of technology. Therefore, the terms used in the present invention should be defined based on the meanings of the terms and the overall content of the present invention rather than simple term names.

Throughout the specification, when a part "includes" a component, it means that it may also include other components, rather than excluding other components, unless otherwise specified. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. This invention may, however, be embodied in many different forms and is not limited to the embodiments set forth herein.

Specific matters including problems to be solved by the present invention, means for solving the problems, and effects of the invention are included in the embodiments and drawings described later. Advantages and features of the present invention, as well as the manner in which they are achieved, will become apparent with reference to the embodiments described in detail below in conjunction with the accompanying drawings.

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

As shown in FIGS. 1 and 2, a combustion apparatus capable of maximizing the operating efficiency and emission performance of a combustor according to a first preferred embodiment of the present invention comprises a gas nozzle section 10 to which gas fuel is supplied, and the gas nozzle section 10 and a first mixing chamber 22 communicating with the gas fuel distribution portion 20 through a first through hole 21 to form a space in which gas fuel is premixed with air. , a second mixing chamber 24 communicating with the gas fuel distributor 20 through a second through hole 23 to form a space in which the gas fuel is premixed with air; the first mixing chamber 22 and the second mixing chamber 24; A turbulent flow generation nozzle portion 30 provided between and communicating with the air nozzle portion 50, which turbulates the gas fuel premixed in the first mixing chamber 22, and the first mixing chamber 22 and the second mixing and swivel nozzle sections 40 for supplying combustion air to the chambers 24, respectively.

In addition, the swirling nozzle part 40 communicates with the first mixing chamber 22 and allows the gaseous fuel injected from the first through hole 21 to vertically contact and mix with the swirling air. The flow path 41 communicates with the second mixing chamber 24, and the gaseous fuel injected from the second through hole 23 is in vertical contact with the air having a lower degree of swirl than the first flow path 41 and is mixed. and a second flow path 42 that allows the flow to flow.

Therefore, the premixture of gaseous fuel and air premixed in the first mixing chamber 22 passes through the turbulent flow generating nozzle portion 30, and the gaseous fuel and air premixed in the second mixing chamber 24 are mixed. The premixed gas that is mixed with the premixed gas and weakly swirled in the second mixing chamber 24 is ignited while maintaining a turbulent flow, thereby suppressing the formation of an internal recirculation area within the flame. reducing the residence time of combustion products at high temperatures and minimizing the generation of hazardous substances.

That is, in the gas fuel distribution section 20 , the gas fuel injected from the first through hole 21 flows through the first flow path 41 provided at the end of the swirl nozzle section 40 communicating with the air inlet section 51 . It collides with the strongly swirled combustion air at right angles and mixes. Further, the gas fuel injected from the second through hole 23 in the gas fuel distribution section 20 passes through the second flow path 42 provided in the central portion of the swirling nozzle section 40 communicating with the air inlet section 51. , is mixed with the combustion air swirled relatively weakly compared to the first passage 41 . This allows the premixed premixed gaseous fuel and air to enter the internal recirculation zone (IRZ , Inner Recirculation Zone) to reduce the residence time of combustion products at high temperatures and minimize the generation of harmful substances such as thermal nitrogen oxides that are generated in proportion to the residence time. That is.

In addition, the turbulent flow generating nozzle part 30 has a circular block shape and is provided with a plurality of fractal-shaped grids over its entirety. and a turbulent flow generating portion 31 that induces a turbulent flow of the premixed gas of air and a cylindrical inner nozzle portion 32 that causes the premixed gas of fuel and air that has passed through the turbulent flow generating portion 31 to flow into the combustion chamber. and including. In addition, the turbulent flow generator 31 is in the form of a cylindrical block and is formed with a predetermined thickness. , To ensure the safety of the system and to increase the combustion efficiency by performing continuous combustion operation without damaging the grid.

First, the gas nozzle part 10 is provided in the combustion apparatus capable of maximizing the operation efficiency and emission performance of the combustor according to the present invention. The gas nozzle part 10 guides external gas fuel to be supplied to the gas fuel distribution part 20 .

The gas fuel distribution part 20 is provided at the end of the gas nozzle part 10 . The gas fuel distributing part 20 has a predetermined space inside and serves to distribute the gas fuel flowing from the gas nozzle part 10 . More specifically, the gas fuel distributor 20 is cylindrical, and a plurality of first through holes 21 are provided at one end of the gas fuel distributor 20 with reference to the cross section. The first through hole 21 communicates the gas fuel distribution part 20 with the first mixing chamber 22 so that the gas fuel supplied from the gas nozzle part 10 is transferred to the first mixing chamber 22 . At this time, the gas fuel injected from the first through-hole 21 in the gas fuel distribution section 20 moves along with the strong swirling motion of the combustion air flowing in from the first flow path 41 to the outlet of the first flow path 41. just before , hits in a jet in cross, mixes with the combustion air, and moves into the first mixing chamber 22 .

Next, a plurality of the first through holes 21 and the second through holes 23 are arranged radially around the central portion of the turbulent flow generating nozzle. In addition, the first through holes 21 are positioned at the same distance from the center of the cross section of the gas fuel distributor 20 as a reference. More specifically, the second through hole 23 is formed so as to communicate with the second flow path 42 provided in the central portion of the swirling nozzle portion 40 without interfering with the first flow path 41 . At this time, the second flow path 42 is formed with a swirling angle at which the swirling motion is weaker than that of the first flow path 41 . Therefore, the second through-hole 23 communicates the gas fuel distribution part 20 and the second mixing chamber 24, and the gas fuel supplied from the gas nozzle part 10 passes through the second flow path 42. are premixed with and moved to the second mixing chamber 24 . In addition, the second through holes 23 are positioned at the same distance from the center of the cross section of the gas/fuel distributor 20 as a reference. That is, the first through-holes 21 and the second through-holes 23 are arranged in a circular shape with a certain interval around the central portion of the turbulent flow generating nozzle portion 30 .

Next, the first through holes 21 and the second through holes 23 are provided in a zigzag shape with the center of the gas/fuel distributor 20 as a reference. That is, the gas fuel supplied from the gas nozzle section 10 is uniformly distributed to the first mixing chamber 22 and the second mixing chamber 24 in the gas fuel distributing section 20 . Also, it is preferable that the number of the first through holes 21 and the number of the second through holes 23 are the same. This is also for the purpose of uniformly distributing the gas fuel supplied from the gas nozzle 10 to the first mixing chamber 22 and the second mixing chamber 24 in the gas fuel distributor 20 . In addition, the cross-sectional diameters of the first through hole 21 and the second through hole 23 are adjusted according to the amount of gas fuel and air, and the gas supplied to the first mixing chamber 22 and the second mixing chamber 24 is controlled. Fuel flow rate can be adjusted. In addition, by always supplying a constant amount of gas fuel regardless of pressure fluctuations in the combustion chamber 52 during combustion, combustion stabilization, which is important in lean combustion such as in a gas turbine combustor, is achieved. can be planned.

Specifically, the diameters of the first through-hole 21 and the second through-hole 23 are set to the respective front and rear ends of the first through-hole 21 and the second through-hole 23 as a condition for the gaseous fuel to flow choke. The pressure differential is fabricated to be maintained at or above 1.6 atm for LNG fuel as an example. At this time, if the diameters of the first through-hole 21 and the second through-hole 23 are set so that the pressure difference is 1.6 atm or more, the pressure from the first through-hole 21 and the second through-hole 23 is The injected gas fuel forms a choked flow with a Mach number of 1.0. Therefore, even after the flow of the premixed gas ejected from the swirl nozzle portion 40 is ignited and burned at the outlet of the swirl nozzle portion 40, the state is not affected by the pressure change inside the combustion chamber 52. , it becomes possible to form a stable and uniform air-fuel mixture.

Next, the first mixing chamber 22 and the second mixing chamber 24 are provided. The first mixing chamber 22 has a space inside and communicates with the gas/fuel distribution section 20 through the first through hole 21 . Therefore, the combustion air that has flowed in from the air nozzle portion 50 flows in from the first flow path 41, and at a point adjacent to the outlet of the first flow path 41 inside the first mixing chamber 22, the gas It collides with the fuel at a right angle and swirls strongly to be premixed.

The second mixing chamber 24 has a space inside and communicates with the gas/fuel distribution section 20 through the second through hole 23 . This is also the point where the combustion air flowing from the air nozzle portion 50 flows from the second flow path 42 and is in contact with the outlet of the second flow path 42 inside the second mixing chamber 24. It collides with gas fuel at a right angle and is turned.

Next, the turbulence generating nozzle section 30 is provided between the first mixing chamber 22 and the second mixing chamber 24 . More specifically, as shown in FIG. 2, the turbulent flow generating nozzle part 30 is provided with a plurality of square lattice holes having a fractal shape inside a circular block. a turbulent flow generator 31 for inducing a turbulent flow of the premixed gas fuel and air, and an inner nozzle for causing the premixed gas fuel and air that has passed through the turbulent flow generator 31 to flow into the combustion chamber 52. a portion 32; First, the turbulent flow generator 31 has a cylindrical shape and is elongated along the longitudinal direction of the inner nozzle part 32. Even if flames adhere to the inner nozzle part 32, structural rigidity of the material is maintained. As a result, the combustion efficiency is increased while ensuring the safety of the system by performing continuous combustion operation without damaging the grid. More specifically, the turbulent flow generating nozzle section 30 is in the shape of a pipe nozzle, and includes a circular block-shaped thick turbulent flow generating section 31 therein. The turbulence generator 31 functions to turbulate the premixed gas fuel and air premixed in the first mixing chamber 22 . That is, the premixture of gas fuel and air passes through a plurality of square lattice holes having a fractal shape of the turbulent flow generator 31, thereby greatly increasing the turbulent flow performance (turbulent flow intensity). .

Also, the length of the turbulent flow generating portion 31 is formed to be about 0.3 to 0.6 times the length of the inner nozzle portion 32 . At this time, when the thickness of the turbulent flow generating part 31 in the longitudinal direction is less than 0.3 times the thickness of the inner nozzle part 32 in the longitudinal direction, the change in load, especially the low load, may occur. The turbulent flow generating section 31 is damaged or broken due to the occurrence of a simmering phenomenon and adhesion of the flame to the inside of the combustor nozzle. As a result, there is a problem that the operation of the combustion device is stopped and the thermal efficiency is rapidly reduced. Also, when applied to combustors such as gas turbines for power generation and aviation, small fragments breaking off from the combustor nozzle can be fatal to the entire system of the gas turbine, just like a bird strike on an aircraft engine. However, there is a problem that it causes physical damage. Further, when the thickness of the turbulent flow generator 31 in the longitudinal direction exceeds 0.6 times the thickness of the inner nozzle part 32 in the longitudinal direction, the holes of the turbulent flow generator 31 There is a problem that the turbulence performance of the premixed air-fuel mixture passing through is significantly reduced, the thermal efficiency is reduced, and the amount of harmful substances such as nitrogen oxides (NOx) is increased. . The reduced turbulence performance also increases the overall size of the combustor system, as the flame length increases, requiring a design that further increases the size of the combustion chamber to match. be. Therefore, the thickness of the turbulent flow generator 31 in the longitudinal direction is 0.3 to 0.6 times the thickness of the inner nozzle part 32 in the longitudinal direction.

In addition, it is preferable that a guide portion 60 is provided to guide the premixed gas fuel and air premixed in the first mixing chamber 22 to flow to the turbulence generating portion 31 .

Also, the turbulent flow generator 31 may be formed with a fractal structure. A fractal structure is a structure that effectively increases the intensity of turbulence, and is a structure in which small shapes are infinitely repeated in a form resembling the overall shape to form the overall shape. Due to certain rules, fractal structures are geometrically the same shape, but are arranged in different sizes and arrangements, so that fluids passing through such fractal structures experience various turbulent lengths. It is a structure that can effectively increase turbulence intensity by generating turbulence length and energy. Such a fractal structure causes the thickness of the fractal grid to decrease according to a constant rate rule. When the turbulent flow generating portion 31 is formed with a fractal structure and the ratio of reduction in the thickness of the fractal lattice is 0.6 or less, the turbulent flow is less than that of the turbulent flow generating portion 31 having radial holes. The intensity will increase by 2-3 times. Therefore, when the turbulent flow generator 31 is configured with such a fractal structure, the turbulent intensity can be effectively increased.

2 to 4, the turbulent flow generator 31 includes a main body 31a supporting the turbulent flow generator 31 and a premixed gas passing therethrough to increase the turbulence intensity of the premixed gas. and a fractal hole 31b. At this time, the main body portion 31a and the fractal hole 31b may have different lengths with respect to the longitudinal direction of the turbulent flow generating portion 31 .

More specifically, referring to FIG. 3, the length of the fractal hole 31b is gradually shortened from the center of the turbulent flow generator 31 toward the outer peripheral surface. Therefore, even if the end of the body portion 31a is damaged by causing the flame to adhere to the end of the body portion 31a when the fire phenomenon occurs at a change in load, especially at a low load, the fractal The turbulence of the premixed gas can be continuously performed without affecting the holes 31b. In other words, by preventing the flame from damaging the fractal holes 31b, the rate of increase in the turbulence intensity of the premixed gas that has passed through the turbulence generator 31 can be maintained continuously. As a result, there is an advantage that the rigidity of the turbulence generator 31 can be increased while maintaining the thermal efficiency of the combustion device.

Also, referring to FIG. 4, the length of the fractal hole 31b is formed longer than the length of the body portion 31a. Therefore, there is an advantage that the turbulence intensity of the premixed gas can be further increased by increasing the time for the premixed gas to pass through the fractal holes 31b.

Next, the ignition device may be provided at the outlet of the swirling nozzle part 40 communicating with the combustion chamber 52 and may be driven by a separate power source. That is, the ignition device ignites a premixture of unburned gas fuel and air injected from the outlet of the swirl nozzle portion 40, and produces a flame field without an internal recirculation zone (IRZ) inside the combustion chamber 52. to form

Next, the air nozzle portion 50 and the swirling nozzle portion 40 communicating with the air inlet portion 51 are provided so that combustion air is supplied to the first mixing chamber 22 and the second mixing chamber 24 . More specifically, the air nozzle part 50 is provided to surround the outer circumferences of the first mixing chamber 22 and the second mixing chamber 24 . Between the air nozzle portion 50 and the swirling nozzle portion 40, a space is provided that communicates with the first mixing chamber 22 and the second mixing chamber 24 and allows air to flow. Therefore, in the first mixing chamber 22 and the second mixing chamber 24, the air inlet portion 51 is the premixture of gaseous fuel and air, and the first flow provided on one side of the swirling nozzle portion 40, respectively. It serves to supply air so that the combustion air introduced from the passage 41 and the second passage 42 are mixed.

That is, the swirling nozzle portion 40 communicates with the first mixing chamber 22 to supply a strong swirling flow of air to the first mixing chamber 22 and the second mixing chamber 24 . and a second flow path 42 for supplying air to the second mixing chamber 24 with a weak swirl flow having a swirl strength of 0.4 to 0.55.

In addition, the first through hole 21 is positioned immediately before the outlet of the first flow path 41 , and the second through hole 23 is positioned on one side of the inner wall of the second flow path 42 . Therefore, the gas fuel supplied from the first through hole 21 collides with the combustion air supplied from the first passage 41 with a strong swirling flow in a jet in cross flow, which is easy to mix, and the efficiency is increased. effectively premixed. Similarly, the gaseous fuel supplied from the second through hole 23 is efficiently premixed with the combustion air having a weak swirling strength supplied from the second flow path 42 .

Hereinafter, the operation of the combustion apparatus capable of maximizing the operating efficiency and emission performance of the combustor according to the present invention will be described in detail with reference to FIGS. 1 to 5. FIG.

First, when the combustion device is operated, the gas fuel flows into the gas fuel distribution section 20 from the gas nozzle section 10, and the supplied gas fuel flows through the first through hole 21 and the second through hole 21 in the gas fuel distribution section 20. The first mixing chamber 22 and the second mixing chamber 24 are divided by two through-holes 23 to move. At this time, in the first mixing chamber 22 and the second mixing chamber 24, the combustion air supplied from the air nozzle portion 50 and the swirl nozzle portion 40 and the air from the first through hole 21 and the second through hole 23 It is premixed with the supplied gas fuel. Thereafter, in the second mixing chamber 24, the air-fuel mixture in the state of weak swirling strength maintains a weak swirling motion around the air-fuel mixture premixed in the first mixing chamber 22 with high swirling strength, Move to the combustion chamber 52 . In this state, the flame is ignited by the ignition device, and a high temperature turbulent premixed flame is formed in the combustion chamber 52 .

At this time, the high-temperature flame generates a large amount of harmful substances such as thermal NOx. As a method of reducing the generation of harmful substances such as thermal NOx, the temperature of the flame is lowered, or the residence time of the high-temperature combustion products in the flame is reduced in the flame field, which is the reaction field. be. By the way, in the case of a gas turbine, it is most effective to raise the temperature at the turbine inlet (TIT, Turbine Inlet Temperature) in order to improve the thermal efficiency of the system. Recently, since it is an essential requirement for all gas turbine combustors, in the case of the method of lowering the flame temperature among the above methods, the thermal efficiency of the entire system of the gas turbine is lowered, so the flame temperature is not lowered. Also, reducing the residence time of the hot combustion products within the flame is the most preferred method.

Therefore, in the first mixing chamber 22, the strong swirling flow of the first passage 41 meets the gas fuel injected from the first through hole 21 in a vertical jet form (Jet in cross). mixed. Thereafter, the turbulent flow is turbulent through the turbulent flow generator 31 mounted inside the turbulent flow generating nozzle section 30 communicating with the first mixing chamber 22 . Thereafter, at the end of the turbulent flow generating nozzle section 30, the premixed air-fuel mixture passes through the second mixing chamber 24 with a weak swirling flow. Thereafter, a premixed flame is formed at the exit of the swirl nozzle portion 40 communicating with the combustion chamber 52 . That is, there is no recirculation zone in the center of the flame and the flame is close to complete combustion. The premixture of gaseous fuel and air premixed in the first mixing chamber 22 passes through the turbulent flow generator 31 and is strongly turbulent. At this time, the premixture of the gaseous fuel and air premixed in the first mixing chamber 22 is prevented from expanding rapidly in the combustion chamber 52 . That is, the premixture of gaseous fuel and air premixed in the second mixing chamber 24 is prevented from spreading outwardly. It is to be. That is, the premixture of gaseous fuel and air premixed in the first mixing chamber 22 injected into the combustion chamber 52 is protected by a weak swirling motion from the second flow path 42 and is strongly turbulent. It is moved to the combustion chamber 52 while maintaining the flow. This minimizes the formation of internal recirculation zones in the flame field generated in the combustion chamber 52, reduces the residence time of the hot combustion products within the flame field, and is closely related to residence time. The generation of harmful substances such as thermal nitrogen oxides can be minimized.

In the following, in the combustion apparatus capable of maximizing the operating efficiency and emission performance of the combustor according to the present invention, an experiment will be conducted to compare the combustion performance according to the thickness of the turbulence generating part and the amount of nitrogen oxides, which is a typical combustion pollutant. will be explained.

As the experimental method, first, considering that the main component of LNG gas fuel is methane (CH ₄ ), high-purity methane gas with a purity of 99.95% was used as fuel in order to improve the accuracy of the experimental results. rice field. Also, depending on the thermal power of the lab-scale combustor in view of the lab-scale flow rate, even in a lean state where the oxidant (air) is relatively high, the oxidant (air) excess state The lean flammability limit performance, which determines whether the combustor can operate normally, is measured by the equivalence ratio, which is the mixture ratio of fuel and oxidizer (air), and the condition of the mixture (temperature , pressure), the numerical value expressed in terms of the adiabatic flame temperature of the equivalence ratio is shown in FIG. In addition, in order to suppress the generation of nitrogen oxides (NOx), recently, most of the low-pollution combustors have a fuel-oxidant mixture ratio of lean burn, like lean burn engines of automobiles. Since it is operated in a (lean combustion) state, the equivalence ratio, which is the mixing ratio, is lowered to 1.0 or less, which is the stoichiometric ratio, while measuring the emission concentration of NOx, which is a nitrogen oxide, FIG. 9 shows the concentration values converted by the concentration of 15% oxygen (O ₂ ), which is the standard for exhaust gas emissions from gas turbine combustors.

As a result of the experiment, referring to FIGS. 8 and 9, as the thickness of the turbulence generator 31 increases, the lean flammability limit increases as well as the TDR (Turn down ratio) performance, which is the range of operable heat capacity of the combustion apparatus. It can be seen that the equivalent equivalence ratio values are relatively increased and the stable flame region in which the combustor can burn fuel even at low equivalence ratios is reduced. Particularly in the case of combustors in gas turbine systems, such a reduction in combustor operating range results in slightly lower lean blow-off (LBO) performance, which is a performance factor for gas turbine combustors, and nitrogen It is confirmed that the amount of pollutants such as oxides (NOx) generated is slightly increased. However, in the case of the plate-shaped turbulent flow generating part 31 having a thickness of 1 mm, when the load changes, especially when the load (heat capacity) is low, a bonfire phenomenon occurs in which the flame burns into the nozzle, and the turbulent flow generation When the flame adheres to the nozzle part 30, it deteriorates due to the adhering flame, and the connecting bars of the thin grid or grid breaks are damaged, resulting in a poor turbulent flow generation function, which significantly reduces the combustion performance. Therefore, a situation arises in which the operation of the combustion device must be interrupted. Moreover, in the case of the combustor of a gas turbine system, a broken (grid) cut from the nozzle of the combustor collides with the rotating blade at the rear end of the combustor rotating at high speed, just like a bird strike in an aircraft engine. catastrophically damage the gas turbine system or gas turbine engine. That is, the combustion device that utilizes the turbulent flow generation part 31 having a thin plate shape with a thickness of about 1 mm experiences a sudden loss of energy as well as the operational performance and reliability of the combustor as a result of repeated continuous suspension of operation. to On the other hand, in the case of the turbulent flow generating section 31 formed with a thickness of 12.5 mm and 25 mm, it has a strength that enables continuous operation regardless of the adhesion of flames due to the bonfire phenomenon. Driving can be carried out continuously. As a result, as the thickness of the turbulent flow generator 31 increases, the operation range of the lean flammable limit, which is the downward combustion stabilization region of the combustion apparatus, and the emission performance of the combustion exhaust gas decrease a little, but for a long period of time, always Due to the characteristics of the combustion apparatus exposed to high-temperature flames, the turbulent flow generator 31 is advantageous in terms of thermal durability, which is directly linked to the product life, and can be operated continuously. It can be seen that being designed with a constant ratio thickness increases efficiency and product reliability due to the most important maintenance issues in combustors.

Hereinafter, a combustion apparatus capable of maximizing the operating efficiency and emission performance of a combustor according to a second embodiment of the present invention will be described in detail with reference to the accompanying drawings. The present embodiment differs from the first embodiment in that the central portion of the turbulent flow generator 231 is formed to swell. In this embodiment, the description of the first embodiment is used for the configuration that overlaps with the first embodiment.

Referring to FIG. 10, the turbulent flow generator 231 may be formed to swell with respect to the direction toward the combustion chamber. That is, when the central portion of the turbulent flow generating portion 231 expands with respect to the direction toward the combustion chamber, the premixture spreads in the circumferential direction of the turbulent flow generating portion 231 and is injected, resulting in a flame. is formed more widely. Therefore, the width of the generated flame is wide and the flat flame is formed with a thin thickness, which is advantageous in that the generation of pollutants such as carbon monoxide and nitrogen oxides (NOx) can be further minimized. There is In addition, even if a bonfire occurs under a low load, the central portion of the flame is extincted and formed in a doughnut-like shape in the case of the flaming structure in which the central portion bulges. This results in a smaller flame size and a quenching effect in which the flames dispersed between small grids and embers weaken the intensity of the flame due to the increased heat loss received from each grid wall. There is an advantage that the thermal damage to the turbulent flow generating section 231 can be reduced by the effect).

Hereinafter, a combustion apparatus capable of maximizing the operating efficiency and emission performance of a combustor according to a third embodiment of the present invention will be described in detail with reference to the accompanying drawings. The present embodiment differs from the first embodiment in that the central portion of the turbulent flow generator 331 is recessed. In this embodiment, the description of the first embodiment is used for the configuration that overlaps with the first embodiment.

Referring to FIG. 11, the turbulence generator 331 may be recessed with respect to the direction toward the combustion chamber. That is, when the central portion of the turbulent flow generating portion 231 is recessed with respect to the direction toward the combustion chamber, the premixture is concentrated in the central portion of the turbulent flow generating portion 231 and injected, thereby generating a flame. formed even narrower. Therefore, the temperature of the generated flame is formed higher, which is advantageous in that the thermal efficiency of the combustion device is increased. In addition, as shown in FIG. 11, when the central portion of the turbulent flow generating portion 331 is a concave shape in which the length of the duct-shaped lattice passage is short at the central portion, the pressure loss of the flow flowing in the central portion is When a fire is generated, the flame is pushed outward, i.e., toward the wall of the nozzle. There is an advantage that the thermal damage to the turbulent flow generating section 331 is reduced by the cooling effect of the heat loss chamber received from the wall of the flame, which spreads and ignites.

Hereinafter, a combustion apparatus capable of maximizing the operating efficiency and emission performance of a combustor according to a fourth embodiment of the present invention will be described in detail with reference to the accompanying drawings. The present embodiment differs from the first embodiment in that the center of the turbulent flow generator 431 is provided at the central portion of the inner nozzle portion 32 with respect to the length direction of the inner nozzle portion 32 . In this embodiment, the description of the first embodiment is used for the configuration that overlaps with the first embodiment.

Referring to FIG. 12 , the center of the turbulence generator 431 is provided at the center of the inner nozzle part 32 with respect to the length direction of the inner nozzle part 32 . At this time, when the center of the turbulence generating part 431 is positioned above the inner nozzle part 32 with respect to the length direction of the inner nozzle part 32, the flow of the premixed gas flows through the lattice holes 31b of the fractal. Although the turbulence is maximized by passing through, the flow swirled through the outer nozzle portion 43 and directly through the second flow path 42 of the swirling nozzle portion 40 on the outer side of the turbulent flow generating nozzle portion 30 . There is a problem that the turbulence intensity weakens before the strong turbulence generated by hitting the target is preserved. However, there is a problem that the thermal efficiency is reduced due to breakage or damage. Therefore, the center of the turbulent flow generator 431 is provided at the center of the inner nozzle part 32 with respect to the length direction of the inner nozzle part 32 . Further, when the center of the turbulent flow generating portion 431 is located at the central portion of the inner nozzle portion 32 with respect to the length direction of the inner nozzle portion 32 , the first flow path 41 to the first mixing chamber 22 The fuel gas and air that flowed into the first mixing chamber 22 flow into the inner nozzle portion 32 along the tapered guide portion 60 whose exit area is narrowed in the longitudinal direction. There is an effect that the fuel gas and the air are uniformly premixed and flowed into the central portion where the center of the turbulence generating portion 431 is located.

In this way, the technical configuration of the present invention described above may be implemented in other specific forms by those skilled in the art to which the present invention belongs without changing the technical idea or essential features of the present invention. It will be understood that

For this reason, the above-described embodiments are to be considered in all respects as illustrative and not restrictive, and the scope of the invention is defined in the following patents rather than in the foregoing detailed description. All modifications or variations as defined by and deriving from the meaning and scope of the claims and their equivalents should be interpreted as falling within the scope of the invention.

The invention of the present application is based on research conducted with the financial resources of the government (Ministry of Trade, Industry and Energy) and with the support of the Korea Institute of Energy Technology Evaluation (Problem No. 2020671010060, Hydrogen Battery Low Energy for Distributed Power Generation Gas Turbines). NOx combustor development.Project number 20181110100290, H-class gas turbine can-type low swirl burner source technology development for power generation).

1 combustion device 10 gas nozzle section 20 gas fuel distribution section 21 first through hole 22 first mixing chamber 23 second through hole 24 second mixing chamber 30 turbulent flow generating nozzle section 31 turbulent flow generating section 32 inner nozzle section 40 swirling nozzle section 41 first flow path 42 second flow path 43 outer nozzle section 50 air nozzle section 51 air inflow section 52 combustion chamber 60 guide section

Claims (3)

a gas nozzle section to which gas fuel is supplied;
a gas fuel distribution unit communicating with the gas nozzle unit to form a space and distributing the gas fuel;
a first mixing chamber that communicates with the gas fuel distribution part through a first through hole and forms a space in which gas fuel is premixed with air;
a second mixing chamber that communicates with the gas-fuel distribution portion through a second through hole and forms a space in which the gas-fuel is premixed with air;
a turbulent flow generating nozzle section provided between the first mixing chamber and the second mixing chamber for turbulent premixture of gaseous fuel and air premixed in the first mixing chamber;
a swirl nozzle portion communicating with the air nozzle portion and supplying combustion air to the first mixing chamber and the second mixing chamber, respectively;
The swivel nozzle part is
a first flow path that communicates with the first mixing chamber and allows the gaseous fuel injected from the first through hole to vertically contact and be mixed with the swirled air;
A second flow path communicates with the second mixing chamber and allows the gaseous fuel injected from the second through hole to vertically contact and mix with air having a lower degree of swirl than the first flow path. and including
The turbulent flow generating nozzle section
a block-shaped turbulent flow generator having a plurality of fractal-shaped lattice holes for inducing a turbulent flow of the premixture of gas fuel and air premixed in the first mixing chamber;
a cylindrical inner nozzle section for flowing the premixture of gaseous fuel and air that has passed through the turbulence generator into the combustion chamber;
The turbulence generation unit
The inner nozzle part is formed long along the longitudinal direction, and maintains rigidity even when flames are attached due to a bonfire phenomenon, and by performing continuous combustion, combustion efficiency is increased,
The length of the turbulent flow generating section is 0.3 to 0.6 times the length of the inner nozzle section ,
The turbulence generation unit
swelled with respect to the direction toward the combustion chamber
A combustion device capable of maximizing the operating efficiency and emission performance of a combustor characterized by: a gas nozzle section to which gas fuel is supplied;
a gas fuel distribution unit communicating with the gas nozzle unit to form a space and distributing the gas fuel;
a first mixing chamber that communicates with the gas fuel distribution part through a first through hole and forms a space in which gas fuel is premixed with air;
a second mixing chamber that communicates with the gas-fuel distribution portion through a second through hole and forms a space in which the gas-fuel is premixed with air;
a turbulent flow generating nozzle section provided between the first mixing chamber and the second mixing chamber for turbulent premixture of gaseous fuel and air premixed in the first mixing chamber;
a swirl nozzle portion communicating with the air nozzle portion and supplying combustion air to the first mixing chamber and the second mixing chamber, respectively;
The swivel nozzle part is
a first flow path that communicates with the first mixing chamber and allows the gaseous fuel injected from the first through hole to vertically contact and be mixed with the swirled air;
A second flow path communicates with the second mixing chamber and allows the gaseous fuel injected from the second through hole to vertically contact and mix with air having a lower degree of swirl than the first flow path. and including
The turbulent flow generating nozzle section
a block-shaped turbulent flow generator having a plurality of fractal-shaped lattice holes for inducing a turbulent flow of the premixture of gas fuel and air premixed in the first mixing chamber;
a cylindrical inner nozzle section for flowing the premixture of gaseous fuel and air that has passed through the turbulence generator into the combustion chamber;
The turbulence generation unit
The inner nozzle part is formed long along the longitudinal direction, and maintains rigidity even when flames are attached due to a bonfire phenomenon, and by performing continuous combustion, combustion efficiency is increased,
The length of the turbulent flow generating section is 0.3 to 0.6 times the length of the inner nozzle section ,
The turbulence generation unit
It is recessed with respect to the direction toward the combustion chamber The center of the turbulent flow generator is
provided at the center of the inner nozzle part with respect to the length direction of the inner nozzle part
Combustion device capable of maximizing the operating efficiency and emissions performance of the combustor of claim 1 or 2 .

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