KR101697123B1 - Burner for reducing NOx - Google Patents

Abstract

The present invention relates to a low NO_X burner installed in a burner installation hole of a combustion chamber. The present invention includes: a tube inserted into a burner installation hole to have a front end exposed to a combustion chamber, and guiding the air to the combustion chamber; a side part having a diameter smaller than the diameter of the tube, and formed at the front end of the tube; a fuel supply pipe placed inside the tube to supply fuel; a diffuser combined with a front end of the fuel supply pipe to be placed at a distance from the inner wall of the tube, and diffusing the air guided by the tube; an air supply passage forming a predetermined gap between the outer surface of the diffuser and the inner wall of the tube, and discharging the air from the tube to the combustion chamber; a plurality of fuel spray pipes combined with the front end of the fuel supply pipe in a radial shape, and spraying the fuel, supplied through the fuel supply pipe, towards the air going through the air supply passage; and a side groove formed in an outer area of the diffuser in which a fuel orifice of the front end of each of the fuel spray pipes is located. The present invention is capable of effectively reducing the generation of prompt NO_X by increasing the quality of the air, supplied to the fuel spray pipes, as well as effectively reducing the generation of thermal NO_X by effectively making the self-recirculation of combustion gas.

Description

Burner for reducing NOx < RTI ID = 0.0 >

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for removing nitrogen oxides (NOx) (hereinafter referred to as " nox "), and more particularly to an apparatus and a method for reducing the generation of thermal NOx by effectively recirculating combustion gases. The present invention relates to a low-knock burner that can be used.

Rust is a compound of nitrogen and oxygen, such as nitrogen monoxide and nitrogen dioxide, which are produced when fossil fuels burn.

Rust is classified into fuel NOx, thermal knock and prompt NOx depending on the generation mechanism. Fuel rust is produced by the oxidation of the nitrogen contained in the fuel during the combustion process. The thermal knots are produced by oxidizing the nitrogen contained in the combustion air in the combustion process after being released at a high temperature of 1300 ° C or higher. Prompt rust is created by exposure to high temperatures above 1000 캜 before the fuel in the high concentration state is mixed with the combustion air.

This rust, together with hydrocarbons, causes photochemical smog caused by sunlight. And the rust can be odorous even if only 1 to 3 ppm exists, it reduces the immunity to respiratory diseases, and reacts with hemoglobin in the blood to form methemoglobin, which interferes with oxygen delivery. And nitrogen dioxide is a reddish brown, irritant gas that is more toxic than nitrogen monoxide, causing acute lung adenoma, obstructive bronchitis, pneumonia. Accordingly, knock reduction techniques for reducing the knox have been researched and developed.

Knox reduction technologies are technologies that reduce the generation of knocks before combustion of fuel according to the mechanism of generation of knox, post combustion techniques to remove the knox after combustion, Which is a reduction in combustion.

The pre-combustion abatement technology has a fuel denitrification technique that removes the nitrogen contained in the fuel. For example, in order to suppress the generation of the fuel knock, the nitrogen component in the fuel is lowered or the oxygen concentration in the combustion region is controlled. However, since the reduction technology before burning requires the removal of nitrogen in the fuel, it takes a lot of facility investment cost, but it is rarely used since it has less knox reduction effect than the facility investment cost.

The post combustion reduction techniques include selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR). In recent years, there has been a great deal of effort to develop exhaust gas denitrification technology because of the tendency that the emission allowance standards of Knox are strengthened all over the world. Among them, the selective catalytic reduction method is widely used because the denitration efficiency is as high as 70 to 90%.

The combustion abatement technologies include low excess air firing technology, burners out of service (BOOS) technology, Over Fire Air (OFA) technology, and the like, as combustion condition modification techniques that change combustion conditions such as combustion temperature and oxygen concentration during combustion. ) Combustion technology, flue gas recirculation (FGR) technology, gas reburn technology, and low knock burners.

The low knox burner is an improvement to suppress the formation of the knox, which is a type of combustor in which fuel and oxygen are combined, and has been studied and developed in such a manner as to reduce the emission concentration of the knox by decreasing the occurrence of the knox (see Non-Patent Document 2 Reference).

The research and development of the low-knock burner reduces the amount of the knock generated by about 40% of the knock generated by the conventional burner in the 1970's, and the air staging of the air staging burner with the knock exhaust concentration of about 60 to 80 ppm ) (The so-called first-generation low-nox burner). Since then, as the regulations on the emission concentration of the Knox have been strengthened, it is possible to reduce about 60% of the generated amount of the knox compared to the general burner and to reduce the combustion concentration of the burned fuel multi-stage burner (so-called second-generation low-nox burner) was developed. In the late 1980s, ultra low knock burners (ULNB) (so-called third generation low knock burners) with a discharge concentration of about 10 to 20 ppm were developed using the principle of fuel gas recirculation.

On the other hand, the above-mentioned low-knot burner poses a problem that the effect of reducing the overall knock is low, considering only the countermeasures for preventing generation of the thermal knots, without taking measures for preventing the generation of the prompt knock actively.

In order to solve the above problems, Korean Patent Registration No. 10-0784881 discloses a method of producing high-temperature flames, rapid mixing of fuel and air, self-recirculation of combustion gases, A low-knock burner capable of simultaneously preventing the generation of the burn-in gas has been proposed.

However, the low knock burner proposed in Korean Patent Registration No. 10-0784881 is generated by the fact that air and fuel are not sufficiently mixed, or an area where sufficient air is not supplied to the fuel occurs. Accordingly, in order to prevent the emission of carbon monoxide, which is the product of incomplete combustion, a large amount of excess air of 1.2 to 1.3 times the amount of fuel is required, which requires a structure improvement for environmentally friendly high-efficiency combustion.

In order to solve the problem of the low-knock burner proposed in Korean Patent Publication No. 10-0784881, Korean Patent Registration No. 10-1466809 discloses a fuel injection system in which air supplied through a space between a fuel injection tube and a side- There has been proposed an low knock burner that allows the fuel injected from the fuel injecting nozzle to be rapidly mixed to reduce the generation of prompt knocks, thereby achieving eco-friendly high-efficiency combustion.

However, not only the low knock burner proposed in Korean Patent Registration No. 10-1466809 but also the low knock burner proposed in Korean Patent Registration No. 10-0784881 has a large distance between the side portion of the tube and the diffuser, There is a problem that the pressure of the air injected through the space between the diffusers is low and the magnetic recirculation of the combustion gas is not effectively performed. Further, there is a problem in that the amount of air supplied to the fuel injection port of the fuel injection pipe through which the fuel is injected is small, so that the generation of the prompt knock can not be effectively reduced.

Korean Registered Patent No. 10-0784881 (Date of Publication: December 14, 2007) Korean Registered Patent No. 10-1466809 (Published Nov. 28, 2014)

 A Study on the Evaluation and Cost Analysis of the Knox Reduction Technology at the Sung-Yong Lee / Kang, Jeong, Korea Environmental Policy Research Institute, December 2002 Research Report,  Kim Jong-ho / Kim Tae-oh / Moon Dong-ho, etc., improvement of the system of spreading the knox burner,

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide an low knock burner that effectively reduces the generation of thermal knots by effectively causing magnetic recirculation of combustion gas.

Furthermore, it is an object of the present invention to provide an low knock burner which can effectively reduce the production of prompt knocks by increasing the amount of air supplied to the fuel injection tube portion where fuel is injected.

The low knock burner according to the present invention is an low knock burner installed in a burner mounting hole of a combustion chamber. The low knock burner is inserted into a burner mounting hole and its tip is exposed to the combustion chamber, Tubes; A sidewall having a diameter smaller than the diameter of the tube and formed at the tip of the tube; A fuel supply pipe disposed inside the tube to supply fuel; A diffuser coupled to a leading end of the fuel supply pipe such that an outer periphery thereof is disposed away from an inner wall of the tube, the diffuser diffusing the air guided by the tube; An air supply passage which forms a gap between the outer periphery of the diffuser and the inner wall of the tube and through which air is discharged from the tube into the combustion chamber; A plurality of fuel injection pipes radially coupled to the front end of the fuel supply pipe for injecting the fuel supplied by the fuel supply pipe toward the air passing through the air supply passage; And respective side grooves are formed in the outer circumferential region of the diffuser where the fuel injection hole at the front end of the fuel injection tube is located.

It is preferable that the distance between the outer periphery of the diffuser and the inner wall of the side wall, that is, the distance d1 between the air supply passages is 3% to 10% of the radius of the diffuser.

At this time, it is preferable that the distance d2 between the bottom surface of the side groove and the fuel injection port is in the range of 0.1% to 75% of the diameter of the fuel injection hole.

The diameter d3 of the side groove is preferably 5% to 15% of the diameter of the diffuser.

On the other hand, a central air injection pipe for injecting outside air in the axial direction of the fuel supply pipe at the tip of the fuel supply pipe may be disposed inside the fuel supply pipe.

According to the low knock burner of the present invention as described above, the magnetic recirculation of the combustion gas is effectively performed, and the generation of the thermal knock is effectively reduced.

Further, the amount of air supplied to the fuel injecting tube portion where the fuel is injected is increased, so that the generation of the prompt knock is effectively reduced.

1 is a side cross-sectional view schematically showing a state in which a low-knock burner according to an embodiment of the present invention is installed in a combustion chamber.
2 is a perspective view schematically showing an under-knox burner according to an embodiment of the present invention.
3 is a view seen in the direction of V in Fig.
Fig. 4 is an enlarged view of Fig. 1B. Fig.
5 is a view for explaining the operation and effect of the low-knock burner according to the embodiment of the present invention.
FIG. 6 is a graph showing the concentration of ox and the concentration of the nox according to the amount of heat input of the low-knock burner according to an embodiment of the present invention.
7 is a table showing the results of testing the low knock burner of the present invention.
8 is a table showing results of testing conventional low-knock burners.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which are intended to illustrate the present invention in a manner that will be readily apparent to those skilled in the art, And this does not mean that the technical idea and scope of the present invention are limited.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an low knock burner according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a side cross-sectional view schematically showing a state in which an low-knead burner according to an embodiment of the present invention is installed in a combustion chamber, and FIG. 2 is a perspective view schematically showing an low-knead burner according to an embodiment of the present invention. Fig. 3 is a view seen in the direction of V in Fig. 1, and Fig. 4 is an enlarged view of Fig.

1 to 4, an low knock burner 100 according to an embodiment of the present invention includes a tube 110 for guiding air to a combustion chamber surrounded by a wall 200, A fuel supply pipe 120 disposed inside the tube 110 for supplying fuel and an outer periphery formed on the inner wall of the tube 110. The fuel supply pipe 120 is provided inside the tube 110, A diffuser 130 which is coupled to the front end of the fuel supply pipe 120 so as to be disposed away from the fuel supply pipe 120 and diffuses the air guided by the tube 110 and a radially- And a plurality of fuel injection pipes 140 for injecting the fuel supplied by the fuel supply pipe 120 toward the air passing between the inner wall of the tube 110 and the outer periphery of the diffuser 130. And a blower 112 coupled to the tube 110 for forcibly supplying outside air to the inside of the tube 110.

When the distance d1 between the outer periphery of the diffuser 130 and the inner wall of the side wall portion 111 or the air supply passage is less than 3% of the radius of the diffuser 130, the diffuser 130 is positioned at the tip of the fuel supply pipe 120 The outer periphery of the diffuser 130 may be caught in the inner wall of the side wall portion 111. [ When the distance d1 between the outer periphery of the diffuser 130 and the inner wall of the side wall portion 111, that is, the distance between the air supply passages exceeds 10% of the radius of the diffuser 130, the outer periphery of the diffuser 130, So that the magnetic recirculation of the combustion gas can not be effectively performed. Therefore, it is preferable that the distance between the outer circumference of the diffuser 130 and the inner wall of the side wall portion 111, that is, the distance d1 between the air supply passages is 3% to 10% of the radius of the diffuser.

A central air injection pipe 121 for injecting outside air from the front end of the fuel supply pipe 120 to the axial direction S of the fuel supply pipe 120 may be disposed inside the fuel supply pipe 120. The diameter of the flame is increased by the air injected by the central air injection tube (121) to prevent the flame from concentrating on the center of the flame. As a result, the temperature of the flame center is prevented from rising excessively, and the amount of generated thermal knock is reduced. The air through the central air injection tube 121 is injected into the combustion chamber FR through the air injection hole formed at the center of the diffuser 130. The air injection hole is formed to be smaller than the inner diameter of the central air injection tube 121 desirable.

Each of the plurality of fuel injection pipes (140) includes a fuel injection hole (141) through which fuel is injected. A plurality of side grooves 131 are formed on the outer circumference of the diffuser 130 to concentrate the air supplied through the tubes 110 to the fuel injection holes 141. 2 and 3, a semicircular lateral groove 131 is formed in the outer peripheral region of the diffuser 130 where the fuel injection openings 141 at the respective ends of the plurality of fuel injection pipes 140 are located, And is formed at the fuel injection pipe 140 position. With this configuration, air supplied through the tube 110 can be concentrated in each of the fuel injection openings 141. [ Thereby, the air is concentrated in each of the fuel injection openings 141 rapidly by the air concentrated by each of the plurality of side grooves 131, thereby reducing the production amount of the prompt knock. Since the distance between the sidewall portion of the tube and the diffuser (the distance between the air supply passages) can be reduced by the space of the side groove 131, the air introduced through the gap between the sidewall portion 111 of the tube and the diffuser 130 The pressure is high, and the magnetic recirculation of the combustion gas is effectively performed.

The bottom surface of the side groove 131 and the fuel injection opening 141 are spaced apart from each other. The vortex EC is formed between the bottom surface of the side groove 131 and the fuel injection opening 141 so that the fuel injected from the fuel injection opening 141 is accelerated by the air supplied through the tube 110 So that the production amount of the prompt knock is further reduced.

The distance d2 between the bottom surface of the side groove 131 and the fuel injection opening 141 preferably ranges from 0.1% to 75% of the diameter of the fuel injection opening 141.

When the air flowing from the side groove 131 to the combustion chamber FR forms the vortex EC by the distance d2 between the bottom surface of the side groove and the fuel injection port, Speed air can be rapidly mixed with the fuel injected from the fuel injection opening 141. [ This rapid mixing ensures that fuel and air are evenly mixed so that the fuel burned in the combustion chamber (FR) does not cause a partial air shortage. The conditions of complete combustion are that the fuel is supplied with the air necessary for combustion around the time of combustion, and rapid mixing satisfies the conditions necessary for complete combustion by appropriately mixing air and fuel. Here, when the air and the fuel are appropriately mixed through the rapid mixing, when the fuel is burned, the incidence of incomplete combustion is minimized, and at the same time, the occurrence of the premix Nox is minimized. This means that the fuel is burned close to complete burning, and in addition, the generation of carbon monoxide (CO) is minimized as the fuel shows combustion characteristics close to complete burning.

The vortex (EC) is not merely a matter of supplying air to the fuel, but it allows the fuel and air to mix uniformly by mixing the air with the fuel to form a vortex. When the fuel particles and the air particles are uniformly mixed, incomplete combustion is minimized because the air particles contribute to the combustion of the fuel particles when the respective fuel particles are burned, and the incomplete combustion is minimized. For example carbon monoxide) is reduced.

The distance d2 between the generation of the vortex region EC and the reduction of the combustion of the fuel and the prevention of the by-products is likely to be small if the distance is too small. If the distance d2 is too long, There is a possibility that some of the fuel is not mixed by the vortex.

If the injection pressure of the fuel injected from the fuel nozzle 4a of the fuel is strong, it is necessary to increase the distance of the distance d2 to some extent because the fuel injected from the fuel injection opening 141 due to the strong injection pressure May not properly mix with the air entering through the tube 110. For example, when the inner diameter of the fuel injection opening 141 is a reference, and the inner diameter of the fuel injection opening 141 is 10 mm, the distance d2 may be 0.01 mm to 5 mm.

If the diameter d3 of the side groove 131 is less than 5% of the diameter of the diffuser 130, the amount of air supplied through the side groove 131 is not sufficient and the fuel injected from the fuel injection opening 141 is quickly It is not diluted and the prompt knock may not be reduced. When the diameter d3 of the side groove 131 exceeds 15% of the diameter of the diffuser 130, the amount of air injected between the outer periphery of the diffuser 130 and the inner wall of the side wall portion 111 is excessively reduced , The magnetic recirculation of the combustion gas is not effectively performed, and the amount of generated thermal knock can not be reduced. Therefore, it is preferable that the diameter d3 of the side groove 131 is 5% to 15% of the diameter of the diffuser 130.

The diffuser 130 has a first air hole 133 having a first diameter d4 and spaced apart from the center of the diffuser 130 by a first distance SD1 and a first diameter d4 And a second air hole 134 having a second diameter d6 that is greater than the second distance SD2 from the center of the diffuser 130 by a second distance SD2.

The first air hole 133 and the second air hole 134 are arranged between the adjacent fuel injection tubes 140 to supply sufficient air to the central portion of the flame to improve the flammability of the flame, To increase the diameter of the diffuser 130 in accordance with the diameter of the diffuser 130, to form the auxiliary flame for enhancing the resistivity of the flame formed in the diffuser 130.

Hereinafter, the operation and effect of the low-knock burner according to one embodiment of the present invention will be described with reference to the drawings.

FIG. 5 is a view for explaining the action and effect of the low-knock burner according to the embodiment of the present invention. FIG. 6 is a graph showing the relationship between the concentration of the knock and the oxygen concentration FIG.

Referring to FIG. 5 together with FIGS. 1 to 4, fuel is supplied through the fuel supply pipe 120 to inject fuel at the fuel injection port 141 of the fuel injection pipe 140, and the tube blower 112 is operated When the air passes through the tube 110 and the central air injection tube 121, fuel and air are mixed. When the mixed fuel and air are ignited by an ignition device (not shown), a flame F is generated.

The distance d1 between the outer periphery of the optimized diffuser 130 and the inner wall of the side wall portion 111 allows the air passing between the outer periphery of the diffuser 130 and the inner wall of the side wall portion 111 to pass through, The flame F is rapidly moved into the combustion chamber FR. The flame F rapidly moves to the inside of the combustion chamber FR and the combustion gas R quickly moves to the outside of the side portion 111 and is mixed with the flame F. [ As a result, the temperature of the flame F is lowered, and the amount of thermal knock generated is effectively reduced. The air passing through the tube 120 is concentrated in each of the plurality of side grooves 131 to rapidly dilute the fuel injected from each of the fuel injection openings 141, thereby effectively reducing the amount of prompt knocks. The bottom surface of the side groove 131 and the fuel injection opening 141 are spaced apart from each other by a distance d2 so that the vortex EC flows between the bottom surface of the side groove 131 and the fuel injection opening 141, So that the fuel injected from the fuel injection opening 141 is more rapidly diluted, and the production amount of the prompt knock is more effectively reduced.

The low knock burner according to an embodiment of the present invention has a combustion chamber size of Φ615 × 1,420 mm, a combustion chamber volume of 0.422 m3, an inlet heat capacity of 944,320 kcal / h (LNG, 10400 kcal / Nm3, As shown in FIG. 6, it was confirmed that the concentration of NOx in the exhaust gas was 15 ppm or less and that the oxygen (O 2) was 3% or more in the exhaust gas of 2,237,725 kcal / m 3 h.

FIG. 7 is a table showing the results of testing the low-knock burner of the present invention under the test conditions of FIG. 6, and FIG. 8 is a table showing the results of the test of the low-knock burner according to the Korean Registered Patent No. 10-0784881 This is a table showing a result. As shown in the table, it can be seen that the low knock burner of the present invention has a remarkably reduced NOx concentration compared to the conventional low knock burner.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined by the appended claims. will be. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

100: Low Knox Burner 110: Tubes
120: fuel supply pipe 121: central air injection pipe
130: diffuser 131: side groove
133: first air hole 134: second air hole

Claims (5)

An under-knot burner installed in a burner mounting hole of a combustion chamber,
A tube 110 inserted into the burner mounting hole and having a tip exposed to the combustion chamber and guiding air to the combustion chamber;
A side portion (111) having a diameter smaller than the diameter of the tube and formed at the tip of the tube;
A fuel supply pipe (120) disposed inside the tube to supply fuel;
A diffuser (130) coupled to a leading end of the fuel supply pipe such that an outer periphery thereof is disposed away from an inner wall of the tube, and diffusing air guided by the tube;
An air supply passage formed at an interval between the outer periphery of the diffuser and the inner wall of the tube and through which air is discharged from the tube into the combustion chamber;
And a plurality of fuel injection pipes (140) radially coupled to the front end of the fuel supply pipe for injecting fuel supplied by the fuel supply pipe toward air passing through the air supply passage,
Semicircular side grooves 131 are formed at the positions of all the fuel injection pipes 140 in the outer circumferential region of the diffuser 130 where the fuel injection holes 141 at the respective ends of the plurality of fuel injection pipes 140 are located,
The distance d2 between the bottom surface of the side groove 131 and the fuel injection opening 141 ranges from 0.1% to 75% of the diameter of the fuel injection opening 141,
Wherein a diameter (d3) of the side groove (131) is 5% to 15% of a diameter of the diffuser (130). The method according to claim 1,
Wherein the distance d1 between the outer periphery of the diffuser and the inner wall of the side wall is 3% to 10% of the radius of the diffuser. delete delete The method according to claim 1,
And a central air injection pipe for injecting outside air in the axial direction of the fuel supply pipe at a front end of the fuel supply pipe is disposed inside the fuel supply pipe.

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