Low-nitrogen stable combustion ammonia gas burner

Abstract

The application discloses a low-nitrogen stable combustion type ammonia gas burner and belongs to the technical field of combustion equipment. The burner comprises three concentrically sleeved sleeves, namely a center sleeve, a stable combustion fire net sleeve and an air rotation sleeve from inside to outside, a blunt body is arranged at the top center of the center sleeve, the bottom end of the center sleeve is open and is communicated with a center inlet pipeline, fuel rotation vanes are arranged between the blunt body and the inner side wall of the center sleeve, a fire net is arranged at the top of the stable combustion fire net sleeve, the bottom end of the stable combustion fire net sleeve is open and is communicated with a stable combustion fire net inlet pipeline, air rotation vanes are arranged at the top of the air rotation sleeve, the bottom end of the air rotation sleeve is open and is communicated with an air inlet pipeline, and the rotation directions of the fuel rotation vanes and the air rotation vanes are opposite. The application can effectively realize the effects of low-nitrogen combustion and stable combustion, avoids the risk of backfire and is suitable for industrial application.

Description

Technical Field

[0001] The invention belongs to the technical field of combustion equipment, and particularly relates to a low-nitrogen stable combustion ammonia burner. Background Art

[0002] Due to the dwindling availability of non-renewable energy sources, such as minerals, renewable clean energy sources like hydrogen are becoming a key research focus. However, compared to the physical and chemical properties of hydrogen, ammonia, as a hydrogen carrier, is easier to liquefy, store, and transport. It possesses a higher volumetric energy density and produces nitrogen and water upon complete combustion, resulting in no pollution or carbon emissions. Therefore, it holds great promise as an energy carrier.

[0003] Most existing ammonia burners simply use a swirl method to achieve a strong mixing of ammonia and air, thereby enhancing the combustion process, or use preheating to enhance the combustion process. However, since the combustion characteristics of ammonia are significantly different from those of natural gas and hydrogen, the use of swirl alone cannot fully achieve a stable combustion effect. In addition, if ammonia and air are directly mixed and burned in equal proportions, although the combustion is relatively stable, there will be a risk of flashback, which is not conducive to industrial application. Summary of the Invention

[0004] Technical problem to be solved: In response to the above technical problems, the present invention provides a low-nitrogen stable combustion ammonia burner, which can effectively achieve the effects of low-nitrogen combustion and stable combustion while avoiding the risk of flashback, and is suitable for industrial applications.

[0005] Technical solution: A low-nitrogen stable combustion ammonia burner comprises three concentrically sleeves, which are, from the inside to the outside, a center sleeve, a stable combustion fire net sleeve and an air swirl sleeve. A blunt body is provided at the top center of the center sleeve, and the bottom end is open and connected to the center inlet pipe. Fuel swirl blades are provided between the blunt body and the inner side wall of the center sleeve; a fire net is provided at the top of the stable combustion fire net sleeve, and the bottom end is open and connected to the stable combustion fire net inlet pipe; an air swirl blade is provided at the top of the air swirl sleeve, and the bottom end is open and connected to the air inlet pipe; the fuel swirl blades and the air swirl blades have opposite rotation directions.

[0006] Preferably, the bluff body and the fire net are both made of heat-resistant alloy.

[0007] Preferably, the bottoms of the central sleeve, the flame stabilizing net sleeve and the air swirl sleeve are all provided with porous media.

[0008] Preferably, the mesh density of the fire net is 4~9mm 2 / grid.

[0009] Preferably, the rotation angles of the fuel swirl blades and the air swirl blades are adjustable.

[0010] Preferably, the pipe end diameter of the center inlet pipe, the stable combustion fire net inlet pipe and the air inlet pipe are all expanded to equal the sleeve diameter.

[0011] Preferably, the gas input into the center inlet pipe is premixed gas of ammonia and air with an equivalence ratio of 1.7-3.0 (corresponding volume ratio of 1:1.2-1:2.1, ammonia:air).

[0012] Preferably, the gas input into the stable combustion fire net inlet pipe is premixed gas of ammonia and air with a volume ratio of 1:3.2-3.57.

[0013] Preferably, the gas input into the air inlet pipe is air with a temperature of 100-150℃. The gas temperature needs to be adjusted according to the operating load of the burner, and a higher temperature should be used when the load is low, and a lower temperature can be used when the load is high.

[0014] Preferably, the gas supply amount in the stable combustion fire net sleeve is 5-10% of the design load of the burner.

[0015] Beneficial effects: 1. A stable flat flame is formed on the surface of the stable combustion fire net sleeve, which preheats and continuously ignites the center ammonia and a small amount of air mixture and the root of the outer swirling air, ensuring stable and continuous combustion of ammonia;

[0016] 2. The flue gas produced after combustion of the stable combustion fire net sleeve can be mixed with the mixture and air under the action of swirling, reducing the oxygen content at the flame surface and achieving the effect of low-nitrogen combustion;

[0017] 3. The center sleeve is provided with a blunt body, which can suck part of the downstream flue gas, further achieving the effect of stable combustion;

[0018] 4. The fuel swirling vanes in the center sleeve and the air swirling vanes in the air swirling sleeve have opposite rotation directions, which can strengthen the mixing of the mixture and air and enhance the flame stability;

[0019] 5. The mixture in the center sleeve is above the combustion limit and explosion limit of ammonia, and there is no possibility of backfire; the mixed air enhances the combustion performance of ammonia, which can further ensure stable and continuous combustion of ammonia;

[0020] 6. The gas supply amount of the stable combustion fire net sleeve is 5-10% of the design load of the entire burner, and this gas supply amount can remain unchanged; when the load is low (generally about 30% load), the gas supply amount of the stable combustion fire net sleeve does not need to be adjusted, and the stable combustion effect of the fire net can be continuously provided. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a sectional view of the structure of the present application;

[0022] Figure 2 This is a schematic diagram of the dimensions of Example 2;

[0023] The numbers in the figure represent the following: 1. Center sleeve; 2. Flame stabilizing net sleeve; 3. Air swirl sleeve; 4. Blunt body; 5. Center inlet pipe; 6. Dye swirl blade; 7. Flame net; 8. Flame stabilizing net inlet pipe; 9. Air swirl blade; 10. Air inlet pipe; 11. Porous medium. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1

[0026] like Figure 1 As shown, a low-nitrogen stable combustion ammonia burner includes three concentric sleeves, which are, from the inside to the outside, a central sleeve 1, a stable combustion flame net sleeve 2 and an air swirl sleeve 3.

[0027] A bluff body 4 made of a heat-resistant alloy is provided at the top center of the central sleeve 1. The bottom end is open and connected to a central inlet pipe 5. Fuel swirl blades 6 are provided between the bluff body 4 and the inner side wall of the central sleeve 1. The rotation angle of the fuel swirl blades 6 can be adjusted according to the required flame shape. Ammonia is mixed with a small amount of air at an equivalent ratio of 1.7 to 3.0 (corresponding to a volume ratio of 1:1.2 to 1:2.1, ammonia:air) and then enters the central sleeve 1 through the central inlet pipe 5. At this time, the mixed gas is higher than the combustion limit and explosion limit of ammonia, and there is no possibility of backfire; however, the mixed air enhances the combustion performance of ammonia, which can further ensure the stable and continuous combustion of ammonia. To ensure uniform air intake, a layer of porous medium 11 is provided at the bottom of the central sleeve 1, so that the mixed gas can evenly pass through the fuel swirl blades 6 to generate swirl.

[0028] The top of the stable combustion fire net sleeve 2 is provided with a fire net 7 made of heat-resistant alloy wire, and its mesh density is 4~9mm 2 The bottom of the flame stabilizing mesh is open and connected to the flame stabilizing mesh inlet pipe 8. A small amount of ammonia and air is evenly mixed at a volume ratio of 1:3.2-3.57 and then enters the flame stabilizing mesh sleeve 2 through the flame stabilizing mesh inlet pipe 8. Under a certain air intake, a stable flat flame is formed above the flame mesh 7. The relatively dense flame mesh 7 also prevents flame flashback. To ensure uniform air intake, a layer of porous medium 11 is installed at the bottom of the flame stabilizing mesh sleeve 2. The above-mentioned ammonia and air mixture achieves optimal combustion.

[0029] The top of the air swirl sleeve 3 is equipped with air swirl blades 9, whose rotation angle can be adjusted according to the desired flame shape. The bottom end is open and connected to an air inlet pipe 10. Air preheated to 100°C to 150°C enters the air swirl sleeve 3 through the air inlet pipe 10. To ensure uniform air intake, a layer of porous medium 11 is installed at the bottom of the air swirl sleeve 3.

[0030] The fuel swirl blades 6 rotate in opposite directions to the air swirl blades 9. Specifically, the fuel swirl blades 6 can be arranged clockwise, while the air swirl blades 9 can be arranged counterclockwise.

[0031] The diameters of the pipe ends of the central inlet pipe 5, the stable combustion fire network inlet pipe 8 and the air inlet pipe 10 are all expanded to be equal to the diameter of the sleeve in which they are located, so as to leave sufficient mixing space for the gases introduced.

[0032] When the burner is running, a layer of stable flat flame will form on the surface of the stable combustion fire net sleeve 2, which will preheat and continuously ignite the mixture of ammonia and a small amount of air in the center and the root of the swirling air on the outside, ensuring the continuous and stable combustion of ammonia; at the same time, the flue gas generated after the combustion of the gas in the stable combustion fire net sleeve 2 can be mixed with the above-mentioned mixture and air for a second time under the action of the swirl, reducing the oxygen content at the flame surface and achieving the effect of low nitrogen combustion; the central sleeve 1 is provided with a blunt body 4, which can suck in part of the flue gas generated downstream, further achieving the stable combustion effect; the fuel swirl blades 6 and the air swirl blades 9 rotate in opposite directions, which can strengthen the mixing of the mixture and air and enhance the flame stability.

[0033] Example 2

[0034] like Figure 2 As shown, R1 is the radius of the bluff body 4, R2 is the radius of the center sleeve 1; R3 is the radius of the stable flame net sleeve 2; R4 is the radius of the air swirl sleeve 3. Based on Example 1, the burner power is limited to 3MW, and the total ammonia flow rate of the burner is 765 Nm 3 / h, R1 size is 0.22m, R2 size is 0.66m, R3 size is 0.76m, R4 size is 1.14m; the center inlet pipe 5 will be 727 Nm 3 / h ammonia and 1037 Nm 3 / h air is mixed and then enters; the inlet pipe 8 of the stable combustion network will be 38Nm 3 / h ammonia and 121 Nm 3 / h air is mixed and then enters; the air flow rate of the outer air inlet pipe 10 is 2390Nm 3 / h.

[0035] The gas supply amount in the stable combustion fire net sleeve 2 is 5% to 10% of the designed load of the burner, and the gas supply amount can be kept unchanged; when the low load (generally about 30% load) is operated, the gas supply amount of the stable combustion fire net sleeve 2 does not need to be adjusted, and the stable combustion effect of the fire net 7 can be continuously provided.

Claims

1. A low-nitrogen stable combustion ammonia burner, characterized in that: The invention comprises three concentric sleeves, which are, from the inside to the outside, a central sleeve (1), a flame stabilizing fire net sleeve (2) and an air swirl sleeve (3). The top center of the central sleeve (1) is provided with a blunt body (4), the bottom end is open and connected to a central inlet pipe (5), and a fuel swirl blade (6) is provided between the blunt body (4) and the inner side wall of the central sleeve (1); the top of the flame stabilizing fire net sleeve (2) is provided with a fire net (7), the bottom end is open and connected to a flame stabilizing fire net inlet pipe (8); the top of the air swirl sleeve (3) is provided with an air swirl blade (9), the bottom end is open and connected to an air inlet pipe (10); the fuel swirl blade (6) and the air swirl blade (9) rotate in opposite directions.

2. A low-nitrogen stable combustion ammonia burner according to claim 1, characterized in that: The material of the bluff body (4) and the fire net (7) are both heat-resistant alloy.

3. A low-nitrogen stable combustion ammonia burner according to claim 1, characterized in that: The bottoms of the central sleeve (1), the flame stabilizing net sleeve (2), and the air swirl sleeve (3) are all provided with porous media (11).

4. A low-nitrogen stable combustion ammonia burner according to claim 1, characterized in that: The grid density of the fire net (7) is 4~9mm 2 / grid.

5. The low-nitrogen stable combustion ammonia burner according to claim 1, characterized in that: The rotation angles of the fuel swirl blades (6) and the air swirl blades (9) are both adjustable.

6. The low-nitrogen stable combustion ammonia burner according to claim 1, characterized in that: The diameters of the pipe ends of the central inlet pipe (5), the stable combustion fire network inlet pipe (8), and the air inlet pipe (10) are all expanded to be equal to the diameter of the sleeve in which they are located.

7. A method for using the low-nitrogen stable combustion ammonia burner according to claim 1, characterized in that: The gas introduced into the central inlet pipeline (5) is a premixed gas of ammonia and air with an equivalent ratio of 1.7 to 3.

0.

8. The method for using the low-nitrogen stable combustion ammonia burner according to claim 7, characterized in that: The gas introduced into the stable combustion fire network inlet pipeline (8) is a premixed gas of ammonia and air with a volume ratio of 1:3.2-3.

57.

9. The method for using the low-nitrogen stable combustion ammonia burner according to claim 7, characterized in that: The gas introduced into the air inlet pipe (10) is air with a temperature of 100°C to 150°C.

10. The method for using the low-nitrogen stable combustion ammonia burner according to claim 7, characterized in that: The air supply volume in the stable combustion fire net sleeve (2) is 5% to 10% of the burner design load.

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