KR101236689B1 - Low nitrogen oxide burner - Google Patents

Abstract

PURPOSE: A low NOx(Nitrogen Oxide) burner is provided to reduce the discharged amount of NOx by maximizing the surface area of flame with multiple flame guide parts. CONSTITUTION: A low NOx burner(1000) comprises a burner body(1100) and multiple flame guide parts(1200). The burner body has an air feeding passage(1110) and is mounted on a burner mounting hole(2100) of a combustion chamber. The flame guide parts are connected to the air feeding passage; guide flame to a combustion chamber; and are adjacently arranged to each other in order to form a circumference. The flame guide part comprises a tube(1210), a fuel supply pipe(1220), a diffuser(1230), and multiple fuel nozzles(1240).

Description

Low Knox Burner {LOW NITROGEN OXIDE BURNER}

The present invention relates to a gas burner, and more particularly to a low-nox burner capable of reducing the production of nitrogen oxides.

In general, nitrogen oxides are produced by fuel NOx produced by the oxidation of chemically bound nitrogen components in the fuel during combustion, and nitrogen in the combustion air is released at high temperature to remove nitrogen molecules in the combustion air. Thermal NOx produced by oxidation, and prompt NOx produced rapidly when hydrocarbon-based fossil fuel is exposed to high temperature in high concentration state.

Among these nitrogen oxides, in particular, the fuel rusty can not be controlled by the combustion technology, and therefore, the low-nox burner has a technical problem in preventing the formation of two nitrogen oxides, thermal and prompt knox.

Conventional low-nox burners have a low-nox burner of the Flue Gas Recirculation that recovers and mixes the exhaust gases into flames. There is a flame burner, a thin film flame burner in which the flame is formed in a film form as a method for increasing the flame surface area, and such a conventional low-nox burner has been attempted to reduce the thermal rust generation by reducing the flame temperature. In order to secure a sufficient combustion space of such a low-nox burner, it is necessary to increase the volume of the combustion chamber by the amount of exhaust gas introduced from the outside, which is inconsistent with recent boiler compaction design trends.

Accordingly, the present applicant implements a high speed flame, a rapid mixing of fuel and air, and a Flue Gas Self Recirculation, and thus, a low knox capable of simultaneously preventing thermal and prompt knox production. A type burner was developed (Registration No. 10-0784881).

However, the low-nox burner has a larger capacity, and thus a larger flame diameter, so that a single large flame is created and the flame temperature increases. In this case, the application of the split supply of combustion air and fuel can further reduce the thermal rust due to the split flame, but additional time and cost will be invested in the design and manufacture, and the emissions of nitrogen oxides will still be improved. It is a reality that much remains. Therefore, it is necessary to develop a low-nox burner that can utilize the existing low-nox burner to the fullest and to reduce the amount of nitrogen oxides even while putting it in a large capacity site.

An object of the present invention is to further reduce the generation of thermal rust during combustion by maximizing the flame surface area to increase radiant heat transfer.

In order to achieve the above object, the low-nox burner according to the embodiment of the present invention is formed with an air supply air supply passage and the burner main body mounted in the burner mounting hole of the combustion chamber, connected to the air supply passage and flame into the combustion chamber And a plurality of flame guide parts arranged to form a circumferential shape adjacent to each other, and the flame guide part includes a tube inserted into a burner mounting hole, a fuel supply pipe disposed at the center of the tube to supply fuel, and a tip of the fuel supply pipe. And a diffuser positioned at the distal end of the fuel supply pipe, and a plurality of fuel nozzles disposed at the tip of the fuel supply pipe to eject fuel into the combustion chamber.

In the low-nox burner according to the embodiment of the present invention, if at least one of the plurality of flame guide parts is located at the circumferential center, at least one of fuel or air is not supplied through the flame guide part located at the center.

In the low-nox burner according to the embodiment of the present invention, fuel is ejected only in the circumferential outer direction in which a plurality of flame guide parts are adjacent to each other.

In the low-nox burner according to the embodiment of the present invention, a plurality of fuel nozzles are disposed radially at the tip of the fuel supply pipe, and at least two or more fuel nozzles are provided among the plurality of fuel nozzles provided in two or more adjacent flame guide parts. The fuel is ejected toward the same point in the empty space formed between two or more adjacent flame guides.

In the low-nox burner according to the present invention, the flame surface area is maximized by the plurality of flame guide parts, thereby extremely reducing nitrogen oxide emissions during the combustion process.

1 is a front view of a low-nox burner according to the present invention.
Figure 2 is a cross-sectional view of the flame guide of the low-nox burner according to the present invention.
3 is a cross-sectional view of a plurality of flame induction portion of the low-nox burner according to the present invention.
4 is a front view of a plurality of flame induction portion of the low-nox burner according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that, in the drawings, the same components are denoted by the same reference symbols as possible. Further, the detailed description of known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, some of the components in the drawings are exaggerated, omitted, or schematically illustrated.

1 is a view showing a state in which a low-nox burner is installed according to the present invention, Figure 2 is a view showing a flame induction portion of the low-nox burner according to the present invention.

As shown in Figure 1 and 2, the low-nox burner 1000 according to the present invention includes a burner body 1100 and a plurality of flame guide portion 1200, the flame guide portion 1200 is a tube 1210 And a fuel supply pipe 1220, a diffuser 1230, and a fuel nozzle 1240. The burner 1000 is mounted by inserting a plurality of flame guide parts 1200 into the burner mounting hole 2100 of the combustion chamber 2000. The burner body 1100 is provided with an air supply passage 1110 through which air is supplied through a blower (not shown), and the flame guide portion 1200 includes a tube 1210 and a tube 1210 connected to the air supply passage 1110. A fuel supply pipe 1220 provided at the center of the fuel cell, a diffuser 1230 having a plurality of air ejection holes 1231, and a spray path 1250 formed between the tip of the tube 1210 and the fuel supply pipe ( A plurality of fuel nozzles 1240 provided at the front end of the 1220 to eject the fuel to the combustion chamber (2000).

A hollow cylindrical tube 1210 is introduced into the burner body 1100, and the tube 1210 is introduced into the combustion chamber 2000. The diffuser 1230 is provided at the tip of the fuel supply pipe 1220, and an injection path for injecting air into the combustion chamber 2000 is formed between the outer circumference of the diffuser 1230 and the tip of the tube 1210. The tip of the tube 1210 is bent in the inner diameter direction to minimize the cross section of the injection path 1250 to maximize the flow rate of air supplied to the combustion chamber (2000). The fuel supply pipe 1220 is disposed at the center of the tube 1210 and the front end of the fuel supply pipe 1220 penetrates into the combustion chamber 2000 through the center of the diffuser 1230, and is connected to the front end of the fuel supply pipe 1220 introduced into the combustion chamber 2000. The plurality of fuel nozzles 1240 are radially formed to spread from the fuel supply pipe 1220. Here, the fuel nozzle 1240 is disposed at different positions along the axial direction of the fuel supply pipe 1220 so that the fuel is ejected uniformly over a wide area, and is provided in two or more adjacent flame guide parts 1200. At least two or more fuel nozzles 1240 among the plurality of fuel nozzles 1240 may be intensively ejected toward the same point in the empty space formed between the adjacent flame guide portion 1200. In addition, each fuel nozzle 1240 is formed to extend to the injection path 1250 of the air formed on the outer peripheral side of the diffuser 1230, the direction orthogonal to the air supplied to the combustion chamber 2000 through the injection path 1250 Ejects fuel. By the injection path 1250 and the fuel nozzle 1240 it is possible to implement a rapid mixing action of air and fuel. The diffuser 1230 is provided with a plurality of air blowing holes 1231 through which air in the air supply passage is blown out to the combustion chamber 2000. The air supplied through the plurality of air blowing holes 1231 forms a plurality of high speed air streams, and vortices are generated around the plurality of high speed air streams, and the vortices uniformly mix fuel and air. Can be. Prompt rust, which is rapidly produced when hydrocarbon-based fossil fuels are exposed to high temperatures in high concentrations, is significantly reduced by this rapid and even mixing of air and fuel.

On the other hand, the fuel is ejected at high speed through the plurality of fuel nozzles 1240, the air is ejected at high speed through the injection path 1250 and mixed while being nearly crossed at right angles, the mixed gas is spark plug (not shown) The combustion gas is generated while the flame is formed in the shape of an janggu which is ignited by and then enlarged in the combustion chamber 2000 and then enlarged. That is, a high speed flame having a very high flame speed is formed by the injection furnace 1250, whereby the flame is formed in a form in which the width is gradually reduced and then gradually enlarged. In addition, since a portion of the tube 1210 is introduced into the combustion chamber 2000 by a predetermined length, the low pressure caused by the high speed flame and the minimum diameter of the flame extends deep into the rear end of the flame. The flame propagation speed is very fast at the minimum diameter of the flame, and the combustion gas at the rear end of the flame is directed to the minimum diameter of the flame, whereby the combustion gas of the combustion chamber 2000 is recycled in the area around the flame. Thermal rust, which is produced by oxidizing nitrogen molecules in the combustion air by releasing nitrogen in the combustion air at a high temperature, is significantly lowered by the recycling of such relatively low temperature combustion gases.

3 is a cross-sectional view showing a plurality of flame induction part of the low-nox burner according to the present invention, Figure 4 is a view showing the front of the plurality of flame induction part of the low-nox burner according to the present invention.

As shown in Figure 3 to 4, the low-nox burner 1000 according to the present invention is connected to a plurality of flame guide portion 1200 to one burner body 1100 to form an air supply passage (1110). The flame induction part 1200 is disposed to form one circumference adjacent to each other. When at least one of the plurality of flame induction parts 1200 is located at the center of the circumference, the flame induction part 1200 is connected to the flame induction part 1200 located at the center. Blocking the air supply passage 1110 or the fuel supply pipe 1220, or by removing the fuel nozzle (1240) or air blowing holes (1231) and injection path (1250) of the flame guide portion 1200 located in the center, Through the flame induction part 1200, at least one of fuel or air may not be ejected. In addition, by reducing the number of fuel nozzles 1240 of the plurality of flame guide portion 1200 arranged on the circumference or by arranging the angle between the fuel nozzles 1240 specifically, the fuel can be ejected only in the outer circumferential direction. The flames induced by the plurality of flame guides 1200 are divided and maintained independently without being merged with each other to maximize the surface area. In particular, the shape of the entire flame does not merge at the center, resulting in sufficient radiant heat transfer of each individual flame. Thermal rust, which is produced by oxidizing nitrogen molecules in combustion air by releasing nitrogen in combustion air at a high temperature, is significantly lowered due to an increase in radiant heat caused by a flame whose surface area is maximized.

Knox emissions measurement results of the low-nox burner according to the embodiment of the present invention are shown in Table 1 below. The measured concentration of nitrogen oxides is the value measured when burning natural gas (city gas), and the standard of low-nox burner within the range of 100 ± 5% of boiler load rate is less than 50 ppm of nitrogen oxides.

division
Burner capacity
[ton / hr]
Flame Guidance Department Measurement result Quantity
[dog] Diameter [mm] Nozzle
[dog] O2
[%] NOx
[ppm] NOx
(O2 4%) [ppm] Comparative example 3.5 One 218 9 3.5 26 25.3 Example 1 3.5 7 121 9 4.37 36 36.8 Example 2 3.5 7 135 6 3.93 29 28.9 Example 3 3.5 7 135 4 3.73 14 13.8

The comparative example is a conventional low-nox burner that the applicant has received an accreditation test from the Environmental Management Corporation on May 4, 2007. Example 1 includes a plurality of flame guide portion 1200 of a smaller diameter than the comparative example. Embodiment 2 includes a plurality of flame guide portion 1200 to eject the fuel intensively toward the same point of the empty space formed between the adjacent flame guide portion 1200 because the number of fuel nozzles 1240 is less than the first embodiment . In the third embodiment, if the plurality of fuel nozzles 1240 provided in the plurality of flame guide parts 1200 are positioned to face the flame guide part 1200 located at the circumferential center formed by the plurality of flame guide parts 1200 adjacent thereto. The number of fuel nozzles 1240 is 6 to 4 per flame induction part 1200 as shown in Table 1 so that fuel is not ejected through the fuel nozzle 1240 toward the flame induction part 1200 located at the center of the circumference. Reduced to the dog, through the flame guide portion 1200 disposed in the center of the columnar to prevent the fuel and air is ejected.

As a result of the measurement of the exhaust gas of Example 1, when using the flame induction part 1200 having a smaller diameter than the comparative example, the nitrogen oxide emission was increased to 36.8 ppm at the 4% oxygen concentration, rather than 25.3 ppm of the comparative example. Able to know. This is because the cross-sectional area of the injection path 1250 is increased by using a plurality of flame induction part 1200 is lowered the rate of blowing of air. Due to the lower air blowing rate, the mixing capacity of fuel and air is lowered, and the amount of self-recirculating circulation is reduced, so that the amount of prompt knox and thermal knox of Example 1 is increased than that of the comparative example.

As a result of the measurement of the exhaust gas of Example 2, when using the flame induction part 1200 having a smaller number of fuel nozzles 1240 than in Example 1 and inputting the same capacity, the amount of nitrogen oxides was 28.9 ppm at an oxygen concentration of 4%. It can be seen that although it was reduced from 36.8 ppm of Example 1, it was still higher than 25.3 ppm of Comparative Example. This is because the number of fuel nozzles 1240 is reduced by the number of flames are aggregated together than in Example 1, but it is analyzed that the flame formed at the center is disturbed by radiant heat transfer by the surrounding flame. In addition, although the diameter of the diffuser 1230 was increased to increase the internal gas recycle amount, it is analyzed that there is a limit in achieving the temperature decrease of the central flame.

As a result of the measurement of the exhaust gas of Example 3, it can be seen that the nitrogen oxide emissions at the same capacity were 13.8 ppm at an oxygen concentration of 4%, which was much lower than those of the first and second examples as well as the comparative example. This is because the total flame is prevented from coalescing in the center, and the radiant heat transfer of the individual flames is sufficiently performed.

As a result, Examples 1 to 3 were identified as low-nox burners having a total amount of nitrogen oxides less than 50 ppm. In particular, Example 3 is a so-called ultra-low-nox burner of less than 14 ppm which far exceeds the acceptance criteria of less than 50 ppm. There is no burner that emits nitrogen oxides below 14 ppm without adopting the external FGR method (Flue Gas Recirculation), and if the low-nox burner 1000 is commercialized, It is expected to contribute more.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of the present invention in order to facilitate description of the present invention and to facilitate understanding of the present invention and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

1000: burner 1100: burner body
1110: air supply passage 1200: flame guidance unit
1210: tube 1220: fuel supply tube
1230: diffuser 1231: air blower
1240 fuel nozzle 1250 injection furnace
2000: combustion chamber 2100: burner mounting hole

Claims (4)

An air supply air path for supplying air, and a burner main body mounted in the burner mounting hole of the combustion chamber,
It is connected to the air supply passage, and guides the flame to the combustion chamber, and comprises a plurality of flame guide portion disposed to form a circumferential adjacent to each other,
The flame guide portion is a tube inserted into the burner mounting hole, a fuel supply pipe disposed at the center of the tube to supply fuel, and a diffuser positioned at the tip of the fuel supply pipe to form an injection path between the tube; And a plurality of fuel nozzles positioned at the tip of the fuel supply pipe to eject fuel to the combustion chamber.
The plurality of fuel nozzles are disposed radially at the tip of the fuel supply pipe, and at least two or more fuel nozzles of the plurality of fuel nozzles provided in two or more adjacent flame guide parts are disposed between the two or more adjacent flame guide parts. Low-nox burners arranged to eject fuel towards the same point in the void that is formed. The method of claim 1,
If at least one of the plurality of flame guide portion is located in the center of the circumferential, low-nox burner is not supplied with at least one of the fuel or air through the flame guide portion located in the center. The method according to claim 1 or 2,
If the plurality of fuel nozzles provided in the plurality of flame guide parts are positioned to face the flame guide part located at the center of the circumference, fuel is not ejected through the fuel nozzles facing the flame guide part located at the center of the circumference. Low-nox burner. delete

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