Rotating flame multi-layer graded trailing edge double reflow low nitrogen burner
Through the design of a rotating flame multi-layer grading tail edge dual reflux low-nitrogen burner, the multi-stage air grading and central rotating flame are coupled with the tail edge dual reflux, which solves the problem of difficult reduction of NOx and CO emissions in the prior art, and realizes the realization of It improves combustion stability and emission efficiency and is suitable for high-temperature furnace high-load burners.
Patent Information
- Application Number
- CN202210555935.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-05-20
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2042-05-20
AI Technical Summary
Existing low-nitrogen burners are difficult to achieve ultra-low NOx and CO emissions in high-temperature furnace high-load burners, and the investment and operation costs of flue gas denitrogenation methods are high.
A rotating flame multi-layer grading tail edge double reflux low nitrogen burner is designed, adopting three-layer air grading inside and outside, central cyclone flame and tail edge double reflux structure. Through multi-stage combustion-assisted air proportional adjustment and nozzle design, the center is formed. The rotating flame and tail edge reflow obliquely toward the flue gas, ensuring combustion stability and reducing NOx and CO emissions.
It achieves ultra-low emissions of NOx and CO, improves combustion stability, reduces the investment and operating costs of burners, and is suitable for high-load heating applications such as industrial boilers, organic heat carrier furnaces and molten salt furnaces.
Smart Images
Figure CN114941840B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a rotating flame multi-layer graded trailing edge double-reflux low-nitrogen burner, belonging to the technical field of burners. Background Art
[0002] As the requirements for NOx emission indicators become more stringent, conventional low-nitrogen burners are unable to meet the requirements for reducing NOx emissions. In order to achieve ultra-low NOx emissions, flue gas denitrification is used in high-temperature furnace and high-load burners such as industrial boilers, organic heat carrier furnaces, and molten salt furnaces. However, the investment cost and operating cost of flue gas denitrification are very high. Therefore, it is necessary to develop a new generation of low-nitrogen gas burners. Summary of the invention
[0003] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art and provide a rotating flame multi-layer graded trailing edge double reflow low nitrogen burner, which effectively reduces the emission of NOx and CO and improves the combustion stability.
[0004] The technical solution of the present invention is:
[0005] A rotating flame multi-layer graded trailing edge double reflow low nitrogen burner comprises a bellows assembly, a burner air inlet, a central fuel gun, a swirl flame stabilizer, a peripheral gas inlet, a gas collector, a peripheral gas gun, and an ignition gun; the bellows assembly is a coaxial three-layer structure, comprising a bellows inner cylinder, a bellows middle cylinder, and a bellows outer cylinder; the burner air inlet is mounted on the bellows assembly, and the burner air inlet is divided into three parts by two layers of air inlet baffles, wherein the upper air inlet baffle is connected to the bellows middle cylinder, and the lower air inlet baffle is connected to the bellows inner cylinder, and the bellows assembly is divided into a primary air area, a secondary air area, and a tertiary air area from the inside out; the wind One end of the box assembly connected to the furnace is the top, and the other end is the bottom; the central fuel gun penetrates from the bottom of the bellows assembly and is installed in the center of the primary air area; the swirl flame stabilizer is installed on the central fuel gun; the gas collector is located at the bottom of the bellows assembly, and the peripheral gas inlet is connected to the gas collector; a plurality of peripheral gas guns are evenly distributed along the inner wall of the bellows inner tube on a circle with the central fuel gun as the center, and are connected to the gas collector, and peripheral gas nozzles are installed on the peripheral gas guns; the ignition gun penetrates from the bottom of the bellows assembly and is installed between the central fuel gun and the peripheral gas guns.
[0006] Preferably, an inner cylinder diffusion cone is installed at the trailing edge of the inner cylinder of the bellows, and a middle cylinder diffusion cone is installed at the trailing edge of the middle cylinder of the bellows. The inner cylinder diffusion cone and the middle cylinder diffusion cone are used to draw in the furnace flue gas to form flue gas reflux; a secondary wind spoiler is installed at the outlet of the secondary air area, and a tertiary wind spoiler is installed at the outlet of the tertiary air area.
[0007] Preferably, the secondary wind spoiler blades and the tertiary wind spoiler blades are distributed consistently in the circumferential direction.
[0008] Preferably, the secondary wind spoiler and the tertiary wind spoiler are V-shaped or flat structures.
[0009] Preferably, the burner air inlet is equipped with an air inlet regulating valve for regulating primary air, secondary air and tertiary air respectively.
[0010] Preferably, the number of the peripheral gas guns is 4 to 30.
[0011] Preferably, the peripheral gas nozzle has a three-layer hole structure, which includes a first layer of spray holes, a second layer of spray holes, and a third layer of spray holes.
[0012] Preferably, the angle between the injection direction of the first layer of nozzles and the axis of the peripheral gas nozzle is satisfy ; The angle between the injection direction of the second layer of nozzles and the axis of the peripheral gas nozzle satisfy The angle between the injection direction of the third layer of nozzles and the axis of the peripheral gas nozzle satisfy .
[0013] Preferably, the first layer of spray holes comprises a plurality of spray holes uniformly distributed along the circumference of the peripheral gas nozzle; the second layer of spray holes and the third layer of spray holes are both single spray holes.
[0014] Preferably, a single nozzle of the second layer of nozzles and the third layer of nozzles is on the same vertical plane with one of the nozzles of the first layer of nozzles; and the injection directions of the three holes on the same vertical plane are tangent to the outer edge of the flame formed by the swirl flame stabilizer.
[0015] The advantages of the present invention compared with the prior art are:
[0016] (1) The rotating flame multi-layer graded trailing edge double reflow low nitrogen burner of the present invention adopts three-layer air classification of inner, middle and outer layers, and adjusts the proportion of combustion-supporting air in each layer through a regulating valve, accurately organizes low nitrogen combustion, further improves combustion stability and reduces NOx and CO emissions;
[0017] (2) The rotating flame multi-layer graded trailing edge double reflow low nitrogen burner of the present invention forms a central rotating flame through multiple peripheral gas spray guns and a central swirl flame stabilizer, sucking in the surrounding flue gas, ensuring flame stability and achieving ultra-low emissions of NOx and CO;
[0018] (3) The rotating flame multi-layer graded trailing edge double reflow low nitrogen burner of the present invention adopts a three-layer porous structure for the peripheral gas nozzle to improve the uniformity of the combustion area and ensure stable combustion;
[0019] (4) The rotating flame multi-layer graded trailing edge double reflow low nitrogen burner of the present invention forms a trailing edge double reflow of trailing edge oblique flue gas reflow and combustion-supporting air blunt body reflow by installing a diffusion cone and spoiler plates distributed along the circumference at the trailing edge of the burner, thereby improving the stability of low nitrogen combustion, further reducing NOx emissions, and ensuring sufficient combustion organization and ultra-low CO emissions. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a front view of the structure of the rotating flame multi-layer graded trailing edge double reflow low nitrogen burner of the present invention;
[0021] Figure 2 It is a side view of the structure of the rotating flame multi-layer graded trailing edge double reflow low nitrogen burner of the present invention;
[0022] Figure 3 It is a top view of the structure of the rotating flame multi-layer graded trailing edge double reflow low nitrogen burner of the present invention;
[0023] Figure 4 This is a schematic diagram of the structure of the peripheral gas nozzle of the rotating flame multi-layer graded trailing edge double reflow low nitrogen burner of the present invention, wherein Figure 4 (a) is a schematic diagram of nozzle arrangement. Figure 4 (b) is a schematic diagram of the nozzle angle;
[0024] Figure 5 It is a schematic diagram of the arrangement of the secondary wind spoiler and the tertiary wind spoiler of the rotating flame multi-layer graded trailing edge double reflow low nitrogen burner of the present invention;
[0025] Figure 6 This is a schematic diagram of the double-reflow principle of the trailing edge of the rotating flame multi-layer graded double-reflow low-nitrogen burner of the present invention, wherein Figure 6 (a) is a schematic diagram of the oblique flue gas reflow principle. Figure 6 (b) is a schematic diagram of the principle of combustion air blunt body reflux. DETAILED DESCRIPTION
[0026] The present invention provides a rotating flame multi-layer graded trailing edge double reflow low-nitrogen burner, which realizes ultra-low emissions of nitrogen oxides and carbon monoxide from the burner by coupling multi-layer air classification, central swirl flame and trailing edge double reflow.
[0027] Figure 1 FIG. 2 shows a preferred embodiment of a rotating flame multi-layer graded trailing edge double reflow low nitrogen burner provided by the present invention. Figure 1 , Figure 2 , Figure 3As shown, the burner mainly comprises: a bellows assembly 4, a burner air inlet 1, a central fuel gun 13, a swirl flame stabilizer 15, a peripheral gas inlet 12, a gas collector 14, a peripheral gas gun 17, and an ignition gun 16; the bellows assembly 4 is a coaxial three-layer structure, including a bellows inner tube 5, a bellows middle tube 6, and a bellows outer tube 7; the burner air inlet 1 is installed on the bellows assembly 4, and the upper and lower air inlet baffles 2 divide the burner air inlet into three parts, and the combustion air is divided into one from bottom to top. Secondary air, secondary air, and tertiary air; wherein the upper air inlet partition is connected to the bellows middle cylinder 6, and the lower air inlet partition is connected to the bellows inner cylinder 5, and the bellows assembly 4 is divided into primary air area, secondary air area, and tertiary air area from the inside to the outside; specifically, the interior of the bellows inner cylinder 5 and the primary air inlet constitute the primary air area, the area between the bellows inner cylinder 5 and the bellows middle cylinder 6 and the secondary air inlet constitute the secondary air area, and the area between the bellows middle cylinder 6 and the bellows outer cylinder 7 and the tertiary air inlet constitute the tertiary air area.
[0028] The above structure constitutes the combustion organization mode of the multi-stage air grading of the rotating flame multi-layer graded trailing edge double reflow low-nitrogen burner of the present invention. The primary air area carries out a combustion, and the fresh air and fuel gas are directly diffused and burned. It is the high point area of NOx generation. The air volume is adjusted to be close to the rich flame extinction boundary to generate the least NOx. The secondary air area is appropriately supplemented with combustion-supporting air to improve combustion stability and reduce CO emissions, ensuring that the rich flame combustion process can be continuously transmitted to the tertiary air. The tertiary air is sprayed out and mixed with the furnace flue gas before participating in the combustion reaction. It is the key to ensure ultra-low NOx emissions, but if the proportion is too high, it will lead to incomplete combustion and unstable combustion.
[0029] Furthermore, an air inlet regulating valve 3 for regulating primary air, secondary air and tertiary air respectively is installed on the burner air inlet 1, and the air inlet regulating valve 3 is a manual or automatic flap valve; by adjusting the proportion of combustion-supporting air at each level, low-nitrogen combustion is accurately organized, further improving combustion stability and reducing NOx and CO emissions.
[0030] In a specific embodiment, natural gas is used as fuel, the proportion of primary air is 20% to 30%, the proportion of secondary air is 30% to 50%, and the proportion of tertiary air is 20% to 50%.
[0031] The central fuel gun 13 penetrates from the bottom of the bellows assembly 4 and is installed in the center of the primary air area. The central fuel gun 13 provides fuel independently and can be a gas gun or a fuel oil spray gun. When it is a fuel oil spray gun, it can realize combined low-nitrogen combustion of fuel and gas; the gas ratio of the central fuel gun 13 is generally controlled at 10%~20% of the total gas volume; the swirl flame stabilizer 15 is installed on the central fuel gun 13; the gas collector 14 located at the bottom of the bellows assembly 4 is connected to the peripheral gas inlet 12, and preferably, the number of peripheral gas inlets 12 is 2; a plurality of peripheral gas guns 17 are evenly distributed along the circumference of the bellows inner tube 5, connected to the gas collector 14, and installed in the primary air area; the gas enters the gas collector 14 through the peripheral gas inlet 12, so that the gas can enter each peripheral gas gun 17 relatively evenly. The number of the peripheral gas guns 17 is set according to the burner load, preferably, the number is 4-30; the peripheral gas guns 17 are equipped with peripheral gas nozzles 18; the ignition gun 16 penetrates from the bottom of the wind box assembly 4, is installed in the primary air area, and is located between the central fuel gun 13 and the peripheral gas guns 17. The peripheral gas nozzle 18 is a three-layer hole structure, such as Figure 4 As shown in (a), it includes a first layer of holes, a second layer of holes and a third layer of holes. Preferably, as Figure 4 (b) shows the angle between the injection direction of the first layer of nozzles and the axis of the peripheral gas nozzle. satisfy The area of the first layer of nozzles is more than 70% of the total nozzle area of the gas nozzle; the angle between the injection direction of the second layer of nozzles and the axis of the peripheral gas nozzle is satisfy The area of the second layer of nozzles is 15% to 25% of the total nozzle area of the gas nozzle; the angle between the injection direction of the third layer of nozzles and the axis of the peripheral gas nozzle is satisfy The area of the third layer of nozzles is 5% to 15% of the total nozzle area of the gas nozzle; the first layer of nozzles is multiple, and are evenly distributed along the circumference of the peripheral gas nozzle, so that the flame is evenly distributed and the uniformity of the combustion area is improved; the second layer of nozzles and the third layer of nozzles are single holes, and are on a vertical plane with one hole in the first layer of nozzles. The above three nozzles are the main injection areas of the gas, and their injection angles are tangential to the swirl flame stabilizer 15, so that the injection direction of the gas is consistent with the rotation direction of the swirl flame stabilizer 15; the third layer of nozzles has an ignition effect to ensure stable combustion of the peripheral nozzles.
[0032] The central fuel gun 13 sprays a small amount of gas and the swirl air behind the swirl flame stabilizer 15 forms a stable initial combustion area. The reaction of gas and fresh air in the initial combustion area is the peak point of NOx generation. Under the premise of ensuring the stability of the overall gas, a small amount of gas reacts with air to form a smaller high-temperature area, and the amount of NOx generated is also small. After that, the third layer of the nozzle holes of the peripheral gas nozzle 18 contacts the initial combustion high-temperature area and is ignited. Since a large amount of initial combustion flue gas has participated in the combustion reaction at this time, the amount of NOx generated is significantly reduced. Even if the gas sprayed from the first and second layers of the nozzle holes of the peripheral gas nozzle 18 contacts the high-temperature flue gas of the combustion reaction of the third-stage nozzle, it is difficult to burn directly due to the lack of oxygen, and can only form a high-temperature mixture of gas and flue gas. Through the design of the injection angle and injection area of the first and second layers of the nozzle holes, the uniformity of the spatial distribution of the gas-to-gas mixture is improved as much as possible, so that after mixing with the second and third winds, a high-temperature uniform combustion flame can be formed in the radiation section of the furnace, and the continuity of combustion is guaranteed, secondary combustion is avoided, and the generation of CO is avoided.
[0033] The rotating flame multi-layer graded trailing edge double-reflow low-nitrogen burner of the present invention forms a central rotating flame through the above structure, produces a tornado effect, draws in surrounding smoke, and ensures flame stability and ultra-low emissions of NOx and CO.
[0034] The inner tube diffusion cone 9 is installed at the trailing edge of the inner tube 5 of the wind box, the middle tube diffusion cone 8 is installed at the trailing edge of the middle tube 6 of the wind box, the secondary spoiler 10 is installed at the exit of the secondary air area, and the tertiary spoiler 11 is installed at the exit of the tertiary air area. Figure 5 As shown, the secondary spoiler 10 and the tertiary spoiler 11 are distributed in the same circumferential direction. The spoiler is a blunt body structure, preferably a V-shaped or flat sheet structure. Figure 6 As shown in (a), the secondary and tertiary air flows pass through the middle tube diffusion cone 8 and the inner tube diffusion cone 9 to form a trailing edge oblique smoke return flow. Figure 6 As shown in (b), the secondary and tertiary air flows pass through the secondary wind spoiler 10 and the tertiary wind spoiler 11 to form a combustion-supporting wind blunt body backflow.
[0035] The rotating flame multi-layer graded trailing edge double reflow low nitrogen burner of the present invention forms a plurality of blunt body reflow zones through a plurality of circumferentially distributed spoilers installed at the trailing edge, thereby improving the stability of low nitrogen combustion. At the same time, the diffusion cone installed at the trailing edge realizes the oblique flue gas reflow at the trailing edge, further improving the mixing of the trailing edge combustion-supporting air and the surrounding furnace flue gas. The trailing edge double reflow of the trailing edge oblique flue gas reflow and the combustion-supporting air blunt body reflow strengthens the graded combustion, improves the stability of low nitrogen combustion, further reduces NOx emissions, and at the same time ensures sufficient combustion organization and ultra-low CO emissions.
[0036] The rotating flame multi-layer graded trailing edge double reflow low nitrogen burner provided by the present invention achieves ultra-low emissions of NOx and CO through multi-stage air classification, coupling of central rotating flame and trailing edge double reflow, and is suitable for large-load heating applications such as industrial boilers, organic heat carrier furnaces, and molten salt furnaces under high combustion-supporting air temperatures.
[0037] When the air preheating temperature is between 250℃ and 300℃ and the fuel is natural gas, the emission conversion value of nitrogen oxides (converted to dry flue gas with an oxygen content of 3.5%) on an organic heat carrier boiler using a conventional burner is basically 400mg / Nm 3 The burner of the present invention can reduce the NOx conversion value to 50mg / Nm 3 Below, combined with flue gas external circulation, the NOx emission conversion value can be achieved <30mg / Nm 3 When the fuel is high hydrogen fuel, the NOx emission value of conventional burners under the same conditions can reach 550mg / Nm 3 The above results show that the combination of this burner and flue gas external circulation can achieve a NOx emission conversion value of <50mg / Nm 3 .
[0038] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.
Claims
1. Rotating flame multi-layer graded trailing edge double reflow low nitrogen burner, characterized in that: The invention comprises a bellows assembly (4), a burner air inlet (1), a central fuel gun (13), a swirl flame stabilizer (15), a peripheral gas inlet (12), a gas collector (14), a peripheral gas gun (17), and an ignition gun (16); the bellows assembly (4) is a coaxial three-layer structure, comprising a bellows inner tube (5), a bellows middle tube (6), and a bellows outer tube (7); the burner air inlet (1) is mounted on the bellows assembly (4), and the burner air inlet (1) is divided into three parts by two layers of air inlet baffles (2), wherein the upper air inlet baffle (2) is connected to the bellows middle tube (6), and the lower air inlet baffle (2) is connected to the bellows inner tube (5), so as to divide the bellows assembly (4) into a primary air area, a secondary air area, and a tertiary air area from the inside to the outside; the bellows assembly (4) is connected to the furnace One end of the connection is the top, and the other end is the bottom; the central fuel gun (13) penetrates from the bottom of the wind box assembly (4) and is installed at the center of the primary air area; the swirl flame stabilizer (15) is installed on the central fuel gun (13); the gas collector (14) is located at the bottom of the wind box assembly (4), and the peripheral gas inlet (12) is connected to the gas collector (14); a plurality of peripheral gas guns (17) are evenly distributed along the inner wall of the wind box inner tube (5) on a circle with the central fuel gun (13) as the center, and are connected to the gas collector (14), and peripheral gas nozzles (18) are installed on the peripheral gas guns (17); the ignition gun (16) penetrates from the bottom of the wind box assembly (4) and is installed between the central fuel gun (13) and the peripheral gas guns (17); An inner cylinder diffusion cone (9) is installed at the trailing edge of the wind box inner cylinder (5), and a middle cylinder diffusion cone (8) is installed at the trailing edge of the wind box middle cylinder (6), and the inner cylinder diffusion cone (9) and the middle cylinder diffusion cone (8) are used to entrain the furnace flue gas to form flue gas reflux; a secondary wind spoiler (10) is installed at the outlet of the secondary wind area, and a tertiary wind spoiler (11) is installed at the outlet of the tertiary wind area; the secondary wind spoiler (10) is distributed circumferentially at the outlet of the secondary wind area, and the tertiary wind spoiler (11) is distributed circumferentially at the outlet of the tertiary wind area; The peripheral gas nozzle (18) has a three-layer hole structure, which comprises a first layer of nozzle holes, a second layer of nozzle holes, and a third layer of nozzle holes; the first layer of nozzle holes comprises a plurality of nozzle holes, which are evenly distributed along the circumference of the peripheral gas nozzle (18); the second layer of nozzle holes and the third layer of nozzle holes are both single nozzle holes; the single nozzle holes of the second layer of nozzle holes and the third layer of nozzle holes are on the same vertical plane as one of the nozzle holes in the first layer; the injection directions of the three holes on the same vertical plane are all tangent to the outer edge of the flame formed by the swirl flame stabilizer (15); The secondary wind spoiler (10) and the tertiary wind spoiler (11) are V-shaped or flat structures.
2. The rotating flame multi-layer graded trailing edge double reflow low nitrogen burner according to claim 1 is characterized in that: The secondary wind spoiler (10) and the tertiary wind spoiler (11) are uniformly distributed in the circumferential direction.
3. The rotating flame multi-layer graded trailing edge double reflow low nitrogen burner according to claim 1 is characterized in that: The burner air inlet (1) is provided with an air inlet regulating valve (3) for regulating primary air, secondary air and tertiary air respectively.
4. The rotating flame multi-layer graded trailing edge double reflow low nitrogen burner according to claim 1 is characterized in that: The number of the peripheral gas guns (17) is 4 to 30.
5. The rotating flame multi-layer graded trailing edge double reflow low nitrogen burner according to claim 1 is characterized in that: The angle between the spray direction of the first layer of spray holes and the axis of the peripheral gas spray head (18) satisfy ; Angle between the injection direction of the second layer of nozzles and the axis of the peripheral gas nozzle (18) satisfy The angle between the injection direction of the third layer of nozzles and the axis of the peripheral gas nozzle (18) satisfy .