KR101063977B1 - Fuel Injection Apparatus for Reburning and Burning System having the same - Google Patents

Abstract

A reburn fuel injector and a combustion system having the same are provided. The disclosed reburn fuel injector is installed at one side of the hollow combustion furnace to supply the main fuel into the combustion furnace, and at least one or more disposed on the outer peripheral surface of the combustion furnace into the furnace And a reburn fuel injection module for injecting reburn fuel, wherein the reburn fuel injected from the reburn fuel injection module is inclinedly supplied into the combustion furnace to circulate by forming a rotational trajectory in the combustion furnace. do.

Also provided is a combustion system having the reburn fuel injector.

The present invention is characterized in that it is possible to reduce the emission of harmful pollutants by increasing the probability of reaction with nitrogen oxides due to the long-term residence of the reburn fuel in the combustion furnace.

Combustion Furnace, Reburn, Rotation, Tangential, Nozzle, Slewer, Recirculation

Description

Fuel injection apparatus for reburning and burning system having the same

The present invention relates to a reburn fuel injector and a combustion system having the same, and more particularly, to a reburn fuel injected by performing a rotational motion in the furnace based on the axial direction of the furnace. It relates to a reburn fuel injector and a combustion system having the same to increase the residence time to increase the reduction rate of pollutants.

At present, mankind's main energy source is hydrocarbon-based fossil fuels. However, the problem of environmental pollution by the product after combustion of fossil fuels has been seriously raised. The main environmental pollutants include nitrogen oxides (NOx) and carbon dioxide (CO ₂ ), as well as carbon monoxide (CO) and soot caused by incomplete combustion of fuels. Nitrogen oxides are known to cause photochemical smog and acid rain and seriously affect plants and animals. For many years, many researchers have studied various ways to reduce NOx. Because of this, low NOx methods currently being tried include exhaust gas recirculation, water or steam injection, multistage combustion of air and fuel, selective non-catalytic reduction (SNCR), and selective catalytic reduction (SCR). catalytic reduction). Recently, developed countries have tried to re-burn NOx in the post-combustion area, and are known to have high efficiency in terms of NOx reduction rate and economic efficiency.

In general, techniques for reducing NOx include a reburning method or a fuel lean reburning method.

The reburn method consists of three reaction zones: primary combustion, reburn combustion, and burnout zone from the fuel nozzle tip. Here, the primary combustion zone is the main combustion zone of a general excess air state, and the reburn zone is formed by injecting about 10-30% of the reburn fuel of the total fuel to form a rich fuel state. It is an area to reduce NOx generated in a small area. Finally, additional air (Burnout air, Overfire air) is supplied to the burnout zone, and unburned hydrocarbon or carbon monoxide (CO) generated from the upstream fuel rich state is oxidized.

Fuel lean reburn is a method of applying reburn, which seeks a simpler structure and higher economy by injecting as little reburn fuel as possible and omitting the air supply in the fuel completion area. While the general reburn method reduces NOx in the reburn zone, which is a fuel-rich region, the fuel lean reburn method aims to reduce NOx in the local fuel rich region, while maintaining a fuel lean overall. Also, the amount of reburn fuel is set to about 5 to 15% of the total amount of fuel. However, since no definite fuel rich zone is formed and the reduction reaction takes place only in the local fuel rich vortex, it is likely to show a low NOx reduction rate compared to normal reburn. In addition, CO may be generated because the supply of the burned air is omitted downstream.

In the above reburning or fuel lean reburning method, the injected hydrocarbon-based reburning fuel causes a reduction reaction with NOx. Therefore, in order to increase the reduction rate of NOx, first, the time that the reburning fuel can stay in the combustion furnace is required. There is a need to be increased.

In addition, it is necessary to smoothly mix the product gas and additionally supplied reburn fuel after combustion of NO present in the furnace in the state where the reburn fuel is continuously supplied to the combustion furnace.

Therefore, efforts to reduce the NO _x and CO due to the reburn mechanism and obtain the maximum efficiency by applying the reburn method and the fuel lean reburn method are continuously required.

In order to solve the above problems, the present invention provides nitrogen oxides and carbon monoxide by allowing the reburned fuel injected into the furnace to flow to the exhaust port side while performing a rotational movement in the furnace based on the axial direction of the furnace. An object of the present invention is to provide a reburn fuel injector and a combustion system having the same.

Reburn fuel injector according to an aspect of the present invention provided to achieve the above object is installed in one side of the combustion furnace of the hollow shape main fuel injection module for supplying the main fuel into the combustion furnace, and the A reburn fuel injection module disposed on at least one outer circumferential surface of a combustion furnace and injecting reburn fuel into the combustion furnace, wherein the reburn fuel injected from the reburn fuel injection module is inclinedly supplied into the combustion furnace As a result, a rotational trajectory is formed and circulated in the combustion furnace.

The combustion furnace is made of a cylindrical shape, the reburn fuel injection module may be configured to maintain a constant acute angle with the tangential direction of the outer peripheral surface of the combustion furnace.

The cross section of the furnace is made of a rectangular shape, the reburn fuel injection module may maintain a constant acute angle with the wall surface of the furnace.

The reburn fuel injection module is composed of a body and a nozzle connected to the body, the fuel discharged from the flow path inside the nozzle may be injected to maintain a constant acute angle with the tangential direction of the outer peripheral surface of the combustion furnace.

The reburn fuel injection module may be formed symmetrically by maintaining a predetermined interval on the outer peripheral surface of the combustion furnace.

Combustion system according to another aspect of the present invention provided to achieve the above object is a hollow combustion furnace, the main fuel injection module for supplying the main fuel into the combustion furnace, at least one or more on the outer peripheral surface of the combustion furnace A reburn fuel injection module disposed to inject reburn fuel into the combustion furnace, and a fuel distribution device for distributing fuel from a fuel tank to the main fuel injection module and the reburn fuel injection module; The reburn fuel injected from the fuel injection module is inclinedly supplied into the combustion furnace so that the reburn fuel forms a rotational trajectory in the combustion furnace.

The fuel distribution device may distribute fuel supplied by a PID (Proportional Integral Derivative) control method.

The combustion furnace is made of a cylindrical shape, the reburn fuel injection module may be configured to maintain a constant acute angle with the tangential direction of the outer peripheral surface of the combustion furnace.

The injection speed V1 of the fuel discharged from the reburn fuel injection module may be set larger than the average speed V2 of the combustion fuel moving in the axial direction of the combustion furnace.

The reburn fuel discharged from the reburn fuel injection module may continuously circulate around the main flame space formed at the front end of the combustion furnace and form a recirculation space.

The amount of reburn fuel discharged from the reburn fuel injection module corresponds to a range of 10% to 20% of the total fuel supplied to the combustion furnace.

The reburn fuel discharged from the reburn fuel injection module may be disposed inside a central portion of the combustion furnace based on the axial direction of the combustion furnace.

In the reburn fuel injector according to the present invention described above, the reburn fuel injected into the combustion furnace forms a fuel lean region around the main flame space of the internal shear of the combustion furnace through a recirculation movement, and at the same time, the center of the combustion reactor is centered. By forming a flow that rotates as a whole, it takes the form of a spring and may slowly flow in the direction of the exhaust port, so that the time for the reburn fuel to stay in the combustion furnace can be significantly increased as compared to the prior art.

In addition, the long-term residence of the reburn fuel in the combustion furnace increases the probability of reaction with nitrogen oxides, thereby reducing the emission of harmful pollutants.

The above objects, features and other advantages of the present invention will become more apparent by describing the preferred embodiments of the present invention in detail with reference to the accompanying drawings. Hereinafter, a reburn fuel injector and a combustion system including the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

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

1 is a block diagram showing an overall system of a combustion furnace to which a reburn fuel injector according to the present invention is applied. Hereinafter, with reference to FIG. 1, the overall structure of the combustion furnace system 100 is equipped with a reburn fuel injector 130 according to the present invention.

Combustion furnace system 100 is a hollow combustion furnace 110, the main fuel injector 120 provided on one side of the combustion furnace 110, the reburn fuel injector disposed in the outer periphery of the combustion furnace 110 ( 130, an exhaust unit 102 provided on the other side of the combustion furnace 110, and a mount unit 112 provided to cover the main fuel injection device 120.

Mount portion 112 is provided with an air supply port 114, the air supply port 114 receives an oxidant such as air from the air blower 105 through the air supply pipe 106.

The combustion furnace 110 may be formed in a cylindrical shape, but is not necessarily limited to a cylinder, but may also be implemented in a rectangular or ellipse shape.

The main fuel injector 120 and the reburn fuel injector 130 are respectively provided so that the injection nozzles 122 and 132 can be located inside the combustion furnace 110. Fine injection holes (not shown) are formed in the injection nozzles 122 and 132 to smoothly spray the supplied fuel into the fine particles. The fuel supplied into the combustion furnace 110 in the present invention can be applied regardless of any kind, such as gas, liquid, or solid fuel.

The fuel tank 103 is located outside the combustion furnace 110, and the fuel tank 103 is connected to the fuel distribution device 104 through the fuel supply pipe 103a. In the fuel distribution device 104, the main fuel supply pipe 124 is connected to the main fuel injection device 120, and the reburn fuel supply pipes 134 and 135 are connected to the reburn fuel injection device 130. The fuel distribution device 104 may be appropriately to distribute the fuel flowing to each injector (120, 130) through the PID control. In the present invention, it may be preferable to be injected and operated by the reburn fuel injector 130 within the range of 10% to 20% of the total amount of fuel injected into the combustion furnace 110.

PID (Proportional Integral Derivative) control is a kind of feedback that allows the output of the system to maintain the reference voltage based on the error between the control variable and the reference input. Proportional Derivative and Proportional Integral control. This is a control method of the combination state. The PID control can be used to control the temperature, pressure, flow rate, and rotation speed in a method that can be used not only to measure the reaction of the automation system but also to control the reaction.

2 is a view showing a reburn fuel injector mounted on a combustion furnace according to an embodiment of the present invention. Hereinafter, a reburn fuel injector 130 according to an embodiment of the present invention will be described with reference to FIG. 2.

When the reburn fuel injector 130 is mounted, the reburn fuel injector 130 is mounted in a state where the tangential line 116 of the circular combustion furnace 110 on which the reburn fuel injector 130 is mounted is set. 130 may be disposed at an angle between the tangent 116 and the first inclination angle θ ₁ . Here, the first inclination angle θ ₁ may be specified in a range of 0 degrees to 90 degrees. Preferably, the first inclination angle θ ₁ may be determined in a range of more than 0 degrees and less than 90 degrees.

The movement path of the reburn fuel injected from the reburn fuel injector 130 by the first inclination angle θ ₁ forms a circular rotation trajectory 136 in the internal space of the combustion furnace 110. In other words, the reburn fuel is inclinedly supplied into the combustion furnace 110 so that the reburning fuel can form a condition capable of staying for a long time along the space inside the combustion furnace 110. When the reburn fuel in the present invention is described in detail to be "sloped", the line connecting the axis of the combustion furnace 110 and the point where the reburn fuel injector 130 is installed on the combustion furnace 110. As a reference, the reburn fuel is injected to deviate from the axial center of the combustion furnace 110. In other words, the reburn fuel is injected to enable the flow on the inner wall of the combustion furnace 110.

Injecting the reburn fuel through the nozzle tip 132 after entering the discharge hole 131 of the reburn fuel injector 130 in a state inclined at a predetermined angle relative to the radial direction of the combustion furnace 110 As a result, the reburn fuel flows through the inner circumferential surface of the combustion furnace 110, thereby creating an environment in which fuel can be easily atomized into fine fuel molecules in the combustion space.

At least one reburn fuel injector 130 may be mounted on the outer circumferential surface of the combustion furnace 110. Preferably, the reburn fuel injector 130 is symmetrically disposed by maintaining a predetermined interval on the outer circumferential surface. As an example, as shown in FIG. 2, the reburn fuel injector 130 may be arranged at four equal intervals and connected to the reburn fuel supply pipes 134 and 135, respectively. On the other hand, each reburn fuel injector 130 may be attached to a separate flow control device (not shown) so that the amount of the reburn fuel is injected.

3 is a view showing a state in which the reburn fuel injector of FIG. 2 is mounted in another embodiment 110 ′ of the combustion furnace. Hereinafter, referring to FIG. 3, the reburn fuel injector 130 is disposed to face the combustion furnace 110 ′ having a polygonal cross section. In the present invention, for the purpose of illustration, the cross section is shown as an example, but is not limited thereto. The reburn fuel injector 130 may be designated in the range of the second inclination angle θ ₂ formed on the wall surface of 0 degrees or more and 90 degrees or less. Similarly to the first inclination angle θ ₁ , the second inclination angle θ ₂ is preferably determined in a range of more than 0 degrees and less than 90 degrees.

Also in the above embodiment, the injection of the reburn fuel is inclined at a predetermined angle in a state perpendicular to the wall surface of the combustion furnace 110 'so that a rotational trajectory is formed in the combustion furnace 110' as shown by reference numeral 137. Can be.

4 is a view showing a reburn fuel injector mounted on a combustion furnace according to another embodiment of the present invention. The reburn fuel injector 140 according to another embodiment includes a body 143 and a nozzle 144, and the fuel supplied from the reburn fuel supply pipes 134 and 135 is a first flow path inside the body 143. Via 141, it is supplied into the combustion furnace 110 through the second passage 142 of the nozzle 144.

The second flow passage 142 of the reburn fuel injector 140 may be disposed at an angle between the tangent 118 and the third inclination angle θ ₃ . Therefore, since the reburn fuel passing through the first flow passage 141 passes through the second flow passage 142, the reburn fuel can be supplied in a state inclined at a predetermined angle with respect to the radial direction of the combustion furnace 110.

Here, the nozzle 144 and the body 143 may be configured as a detachable unit, by configuring the range of the third inclination angle (θ ₃ ) of the nozzle 144 in various ways, the user replaces only the nozzle 144 This makes it easy to change the injection direction of the reburn fuel. In addition, there is an advantage that it is possible to increase the economic efficiency by allowing only the nozzle 144 to be replaced.

The following chemical formula shows the decomposition of NO in the process of combustion of the reburn fuel in the present invention.

C, CH, CH2 + NO-> HCN + ... (1) HCN + O-> NCO + H (2)

NCO + H-> NH + CO (3) NH + H-> N + H2 (4)

N + NO-> N2 + O (5)

In Formula (1), CHi-based radicals generated in the process of partial oxidation and pyrolysis of hydrocarbon fuel injected into the reburn fuel react with NO to form HCN, and Equations (2) to (5) are HCN It shows a series of processes to be reduced to N2.

5 is a schematic diagram showing a state in which reburn fuel flows in a combustion furnace according to the present invention, and FIG. 6 is a correlation between an injection speed of reburn fuel in a combustion furnace and a flow rate in a combustion furnace axially moving in the combustion furnace. 7 is a schematic diagram illustrating a combustion flow state centering on a recirculation flow of reburn fuel injected into a combustion furnace, and FIG. 8 is a diagram illustrating a combustion furnace axial distance according to injection of reburn fuel. It is a graph showing the NOx reduction rate.

1, 5 and 6, the fuel 110 through the fuel tank 103 and the fuel distribution device 104, the combustion furnace 110 by the main fuel injector 120 embedded on the mount 112 The main flame space 162 is formed at the inlet side. The hydrocarbon-based fuels burned in the main flame space 162 react with the oxidant and move toward the exhaust portion 102 along the axial direction of the combustion furnace 110 as shown by reference numeral 166.

In the above process, the fuel injected from the reburn fuel injector 130 moves in a circular motion as shown by reference numeral 164 on the inner circumferential surface of the combustion furnace 110. Combining the flows of the reference numerals 164 and 166 eventually causes combustion. Proceeding while maintaining the coil shaped flow form 168 in the furnace (110).

As shown in FIG. 5, in order to implement a flow in a rotational direction in the combustion furnace 110 of the burned fuel, the injection speed value V1 of the reburned fuel moves in the axial direction of the combustion furnace 110. It is preferable that it is larger than (V2). When V2 is larger than V1, the property of moving in the axial direction of the combustion furnace 110 is relatively greater, which may adversely affect the rotational motion of the reburned fuel, so that the injection speed of the reburned fuel V1 is faster than V2. Required. Reference numeral 118 of FIG. 6 represents an arbitrary cross section perpendicular to the axis of the combustion furnace 110 at the point where the reburn fuel is injected, so that the flow 165 of the fuel burned in the main flame space 162 becomes 118) is shown entering in a direction perpendicular to. Here, V1 and V2 of FIG. 5 may be described based on the cross section 118 described above.

As described above, the reburn fuel injectors 130 and 140 may be used alone or mixed with each other, so that the reburn fuel and the main fuel may be more efficiently mixed in the combustion furnace 110 and 110 ', thereby maximizing NOx reduction efficiency. do.

Meanwhile, the reburn fuel introduced into the combustion furnace 110 performs a specific behavior in the combustion furnace 110 by performing a recirculation flow around the main flame space 162. Hereinafter, FIGS. 7 and 8 will be described. This section describes the recirculation flow process of reburn fuel.

First, a specific experiment of the present invention is designed for the reburn experiment through a unit combustor (2,000,000 kcal / hr) of a multiburner system applied to a 6t / h class combustion furnace. The inner wall of the furnace is surrounded by a water pipe, which is connected to an external drum to supply water to the furnace wall at a constant temperature and flow rate. In the case of operating with the maximum load condition of 100% inside the furnace, NOx decreases gradually as the reburn fuel ratio increases. As a result of the experiment, the amount of reburned fuel discharged from the reburned fuel injector 130 is maintained in the range of 10% to 20% of the total fuel supplied to the combustion furnace 110. It may be desirable for efficient reduction.

7, a substantial portion of the fuel injected from the reburn fuel injector 130 undergoes a recirculation motion on the region between the inner wall of the combustion furnace 110 and the main flame space 162 (see 163). . The injected reburn fuel starts moving along the inner wall of the combustion furnace 110 toward the upper direction of the combustion furnace 110 in which the main fuel injection device 120 is located. Subsequently, the recombustion fuel whose movement direction is changed at the upper end of the combustion furnace 110 has a flow form away from the main fuel injection device 120 under the influence of the flow flow of the main flame space 162.

As described above, the reburn fuel forms a continuous recirculation motion space 163 near the main flame space 162, and consequently, forms an overall fuel lean area. The reburn fuel affected by the temperature of the main flame space 162 undergoes a reburn process in a natural high temperature atmosphere to reduce the nitrogen oxides. The reburn fuel leaving the recirculation space 163 is mixed with the gas burned in the main flame space 162 and flows to the rear end side of the combustion furnace 110 (see reference numeral 167).

Referring to the graph of FIG. 8, the horizontal axis represents the axial distance from the main fuel injection device 120 in the combustion furnace 110, and the vertical axis represents the NOx reduction rate according to the injection at the axial distance. NOx reduction rate,%). In this case, the ratio of the total supply fuel of the reburned fuel (rff, reburn fuel fraction) is varied by dividing it into four separate lines at 3% intervals within the range of 4% to 13%. A linear graph is shown.

The characteristics of the present invention based on FIG. 8 are as follows.

When the total axial length of the combustion furnace is 1.2 m, the point where the reburn fuel is injected may be set to the point where the reburn fuel is injected as the intermediate point 0.6 m. Referring to the graph, it can be seen that the NOx reduction rate increases with a steep slope in the course of progressing the axial distance of 0.1 m to 0.4 m on the horizontal axis (see reference numeral 171). As an example, referring to the diagram with a rff (reburn fuel fraction) ratio of 13%, the NOx reduction rate is located in the vicinity of 10% at an axial distance of 0.1m and the NOx reduction rate is about 40% at an axial distance of 0.4m. You can see the skyrocketing.

Looking at the graph as a whole, it can be seen that the NOx reduction rate is rapidly increased in the space between the front end of the combustion furnace 110 and the injection point of the reburn fuel, and there is no increase trend since the injection point of the reburn fuel. have. As can be seen in Figure 7, it can be determined that the NOx is significantly reduced during the combustion of the reburned fuel is introduced into the front end of the combustion furnace 110 by the recirculation flow.

As described above, in the present invention, a substantial portion of the reburn fuel supplied to the combustion furnace 110 continuously forms a fuel lean space by the recirculation flow 163 based on the main flame space 162, and the nitrogen oxides. And the other part is mixed with the combustion gas moving from the main flame space 162 to form a vortex, and forms a fuel lean region at the rear end of the main flame space 162 to further add NOx and CO. Support mitigation. In particular, in the present invention, to properly select the reburn fuel injection position to facilitate the recirculation flow is an essential part for effective reduction of NOx, and the reburn fuel injector based on the axial direction of the combustion furnace 110. 130 may be disposed in the central portion of the furnace 110. In addition, since the recirculation motion occurs at the leading end region of the combustion furnace 110, the reburn fuel injector 130 is an area between the center of the combustion furnace 110 and the main fuel injection device 120, that is, the combustion furnace 110. It is preferable to arrange | position inside the center part of ().

As a result of the experiment according to the reburn fuel injection method according to the present invention it can be seen that the reduction efficiency of the nitrogen oxide is increased by about 16 to 20% compared to the existing reburn method. It may be desirable to maintain the furnace temperature at 900 degrees or higher in order to induce smooth NOx reduction and to suppress CO production during reburn fuel injection. In addition, the present invention can be applied to both the reburn method and the fuel-lean reburn method.

While preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described specific embodiments. That is, those skilled in the art to which the present invention pertains can make many changes and modifications to the present invention without departing from the spirit and scope of the appended claims, and all such appropriate changes and modifications are possible. Equivalents should be considered to be within the scope of the present invention.

1 is a configuration diagram showing an overall system of a combustion furnace to which a reburn fuel injector according to the present invention is applied;

2 is a view showing a reburn fuel injector mounted on a combustion furnace according to an embodiment of the present invention;

3 is a view showing a state in which the reburn fuel injector of FIG. 2 is mounted in another embodiment of a combustion furnace;

4 is a view showing a reburn fuel injector mounted on a combustion furnace according to another embodiment of the present invention;

5 is a schematic diagram showing a state in which reburn fuel flows in a combustion furnace according to the present invention;

6 is a conceptual view for explaining a correlation between the injection speed of the reburn fuel in the combustion furnace and the flow rate in the combustion furnace axially moving in the combustion furnace;

7 is a schematic view showing a combustion flow centered on the recycle flow of the reburn fuel injected into the combustion furnace, and

8 is a graph for explaining a reduction rate of NOx in a combustion furnace according to the present invention.

<Description of the symbols for the main parts of the drawings>

100 combustion system 102 exhaust

103: fuel tank 104: fuel distribution device

105: air tank 106: air supply pipe

110,110 ': Combustion furnace 112: Mount

114: air supply port 116: tangential

120: main fuel injection device 122,132: injection nozzle

124: main fuel supply pipe 130: reburn fuel injection device

131: discharge hole 132: nozzle tip

134,135: auxiliary fuel supply pipe 136,137: reburn fuel rotation

141: first euro 142: second euro

143: body 144: nozzle 162: main flame space 163: recirculation space

Claims (12)

A main fuel injection module installed at one side of the combustion furnace having a hollow shape and supplying main fuel into the combustion furnace; And And a reburn fuel injection module disposed on at least one outer circumferential surface of the furnace to inject a reburn fuel into the furnace. The reburn fuel injected from the reburn fuel injection module is inclined into the combustion furnace to form a rotational trajectory in the combustion furnace to circulate. The method of claim 1, The combustion furnace is made of a cylindrical, the fuel injection device characterized in that the reburn fuel injection module is configured to maintain a constant acute angle with the tangential direction of the outer peripheral surface of the combustion furnace. The method of claim 1, The cross section of the combustion furnace is made of a polygonal shape, wherein the reburn fuel injection module is configured to maintain a constant acute angle with the wall surface of the furnace. 3. The method of claim 2, The reburn fuel injection module is composed of a body and a nozzle connected to the body, wherein the fuel discharged from the flow path inside the nozzle is injected to maintain a constant acute angle with the tangential direction of the outer peripheral surface of the combustion furnace Fuel injector made. The method of claim 4, wherein The reburn fuel injection module is characterized in that the fuel injection device is formed symmetrically by maintaining a predetermined interval on the outer peripheral surface of the combustion furnace. Hollow furnace; A main fuel injection module for supplying main fuel into the combustion furnace; A reburn fuel injection module disposed on at least one outer circumferential surface of the furnace to inject reburn fuel into the furnace; And A fuel distribution device for distributing fuel from a fuel tank to the main fuel injection module and the reburn fuel injection module, The reburn fuel injected from the reburn fuel injection module is inclinedly supplied into the combustion furnace so that the reburn fuel forms a rotational trajectory within the combustion furnace. The method of claim 6, The fuel distribution device is a combustion system, characterized in that for distributing the fuel supplied by the PID (Proportional Integral Derivative) control system. The method of claim 6, The combustion furnace is made of a cylindrical shape, the recombustion fuel injection module is a combustion system, characterized in that to maintain a constant acute angle with the tangential direction of the outer peripheral surface of the combustion furnace. The method of claim 8, The injection speed (V1) of the fuel discharged from the reburn fuel injection module is set to be larger than the average speed (V2) of the combustion fuel moving in the axial direction of the combustion furnace. The method of claim 6, The reburn fuel discharged from the reburn fuel injection module continuously circulates around the main flame space formed at the front end of the combustion furnace and forms a recirculation space. The method of claim 10, The amount of reburn fuel discharged from the reburn fuel injection module is in the range of 10% to 20% of the total fuel supplied to the furnace. The method of claim 10, And the reburn fuel discharged from the reburn fuel injection module is disposed inside a central portion of the furnace based on the axial direction of the furnace.

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