A hydrogen stable combustion ammonia burner

Abstract

The present invention discloses a hydrogen stable combustion ammonia burner, the structure from the center to the outside includes a coaxially arranged first-stage hydrogen spray gun, a first-stage cyclone, a first-stage ammonia spray gun, a second-stage cyclone, a second-stage hydrogen spray gun, a second-stage ammonia spray gun, a direct current wind interlayer, a third-stage hydrogen spray gun, and a third-stage ammonia spray gun. Ammonia and hydrogen enter the ammonia gas collecting ring and the hydrogen gas collecting ring respectively, and each fuel realizes three-stage fuel classification through spray guns designed at different radial positions; wherein, the second-stage hydrogen spray gun and the second-stage ammonia spray gun are arranged alternately in the second-stage cyclone; the third-stage hydrogen spray gun and the third-stage ammonia spray gun are arranged in a coaxial sleeve type. The combustion-supporting wind enters from the combustion-supporting wind inlet, and is divided into three stages through the first-stage cyclone, the second-stage cyclone, and the direct current wind interlayer, wherein the first-stage cyclone is a strong cyclone, and the second-stage cyclone is a weak cyclone. The present invention uses ammonia as the main fuel and hydrogen as the auxiliary fuel, and performs staged combustion and stage-by-stage stable combustion, thereby improving the stability and burnout of ammonia combustion and reducing nitrogen oxide emissions.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal energy engineering and relates to a burner, in particular to a hydrogen-combustion-stable ammonia burner. Background Art

[0002] The current "carbon peak" goal has made the search for "carbon-free fuel" a focus. Hydrogen is certainly the most ideal ultimate fuel, but its preparation cost is still high, and due to its physical properties, the transportation and storage costs are high and difficult. At this stage, it is uneconomical and unrealistic to carry out large-scale construction of pure hydrogen combustion systems.

[0003] Similar to hydrogen, ammonia is also a carbon-free combustible gas and has the potential to become a "carbon-free fuel". Ammonia can be liquefied at 0.8MPa at room temperature, which greatly reduces the difficulty of transportation. The industry has nearly a hundred years of experience in the use of ammonia. Its preparation, transportation, and storage facilities and experience are very mature, and the cost is relatively low. Therefore, ammonia combustion has the potential for large-scale application.

[0004] However, the chemical properties of pure ammonia as a fuel have the following disadvantages: 1. High ignition point; 2. Low flame propagation speed; 3. Narrow ignition range.

[0005] At present, the design of gas burners focuses less on ammonia fuel, and even less on hydrogen-ammonia coupling utilization. Moreover, most designs focus on the control of nitrogen oxide emissions, and there is still room for further discussion on the consideration of stable combustion and comprehensive fuel utilization. Therefore, it is necessary to develop a new type of hydrogen stable combustion ammonia burner for hydrogen-ammonia combustion system to achieve "carbon-free combustion" while ensuring the safe and stable operation of the system. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a hydrogen stable combustion ammonia burner. The burner of the present invention can use hydrogen as a stable combustion fuel to make ammonia burn stably and achieve the effect of "carbon-free combustion".

[0007] The technical solution adopted by the present invention is as follows:

[0008] A hydrogen stable combustion ammonia burner comprises a burner shell and a DC air cylinder, wherein the DC air cylinder is coaxially arranged in the inner cavity of the burner shell, the DC air cylinder is coaxially provided with a primary hydrogen spray gun, a primary cyclone and a secondary cyclone, the primary cyclone and the secondary cyclone are arranged at the outlet end of the DC air cylinder, the primary hydrogen spray gun is located at the axis of the DC air cylinder, the primary cyclone is sleeved at the outlet end of the primary hydrogen spray gun, and the secondary cyclone is sleeved on the outer ring of the primary cyclone; there is a A DC wind interlayer is formed at a preset distance; a plurality of primary ammonia spray guns are evenly distributed around the primary hydrogen spray gun, and the outlet of the primary ammonia spray gun is located at the outlet of the primary cyclone; a plurality of secondary hydrogen spray guns and secondary ammonia spray guns are evenly arranged around the primary ammonia spray gun, and the secondary hydrogen spray guns and the secondary ammonia spray guns are arranged alternately; a plurality of tertiary ammonia spray guns are evenly distributed in the annular cavity between the DC wind tube and the burner shell, and a tertiary hydrogen spray gun is coaxially arranged in the inner cavity of each tertiary ammonia spray gun. The DC wind tube is a cylindrical body with a bottom at one end, and the bottom side is located inside the burner shell, and the open side faces the outlet of the burner shell.

[0009] Preferably, the outlet of the first-stage hydrogen spray gun is provided with a bowl-shaped flow-guiding blunt body, the bowl bottom of the bowl-shaped flow-guiding blunt body is a smooth curved surface, the bowl bottom of the bowl-shaped flow-guiding blunt body is located inside the first-stage hydrogen spray gun, the bowl mouth of the bowl-shaped flow-guiding blunt body is located outside the outlet of the first-stage hydrogen spray gun, and there is an annular gap between the bowl mouth of the bowl-shaped flow-guiding blunt body and the outlet of the first-stage hydrogen spray gun.

[0010] Preferably, the outlet end face of the primary ammonia spray gun is flush with the swirl blades of the primary cyclone through which it passes.

[0011] Preferably, the outlet end face of the secondary hydrogen spray gun is flush with the swirl blades of the secondary cyclone through which it passes, and the outlet end face of the secondary ammonia spray gun is flush with the swirl blades of the secondary cyclone through which it passes; more preferably, the secondary hydrogen spray gun and the secondary ammonia spray gun are preferably located on the same circle.

[0012] Preferably, the outlet of the three-stage hydrogen spray gun is located 15-25 cm upwind of the outlet of the three-stage ammonia spray gun, and the outlet of the three-stage hydrogen spray gun is located between the outlets of the three-stage ammonia spray gun to form a fuel gas mixing section.

[0013] Preferably, the outlet of the three-stage ammonia spray gun extends out of the outlet end of the burner housing by a distance of 30-50 cm.

[0014] Preferably, the outlet of the first-stage hydrogen spray gun, the first-stage cyclone and the second-stage cyclone are all located inside the outlet of the DC air cylinder.

[0015] Preferably, the swirl intensity of the primary cyclone is stronger than that of the secondary cyclone.

[0016] Preferably, the blade angle of the first-stage cyclone is 45°-60°, and the number of blades is 8-12; the blade angle of the second-stage cyclone is 30°-45°, and the number of blades is 16-24.

[0017] Preferably, an ammonia fuel inlet, an ammonia fuel gas collecting ring, a hydrogen fuel inlet, a hydrogen fuel gas collecting ring and a combustion-supporting air inlet are provided on the burner shell. The combustion-supporting air inlet is connected to the DC wind tube, and the combustion-supporting air inlet is preferably connected to the side wall of the DC wind tube with a bottom; the ammonia fuel inlet is connected to the fuel gas collecting ring, and the first-stage ammonia spray gun, the second-stage ammonia spray gun and the third-stage ammonia spray gun are all connected to the ammonia fuel gas collecting ring; the hydrogen fuel inlet is connected to the hydrogen fuel gas collecting ring, and the first-stage hydrogen spray gun, the second-stage hydrogen spray gun and the third-stage hydrogen spray gun are all connected to the hydrogen fuel gas collecting ring; the ammonia fuel gas collecting ring and the hydrogen fuel gas collecting ring are preferably arranged at a position between the bottom of the DC wind tube and the bottom of the second-stage ammonia spray gun, so as to facilitate the arrangement of the connecting pipes of each spray gun; the ammonia fuel inlet, the hydrogen fuel inlet and the combustion-supporting air inlet are preferably arranged on the outer wall of the burner shell, so as to facilitate the connection of each gas pipeline; a burner back plate is also provided on one side of the bottom of the burner shell;

[0018] The swirl blades of the first-stage cyclone are reserved with a high-energy ignition rod installation opening; the swirl blades of the second-stage cyclone are reserved with a fire-viewing mirror installation opening and a flame detector installation opening;

[0019] The number of primary ammonia spray guns is 4-6; the number of secondary ammonia spray guns is 8-12; the number of tertiary ammonia spray guns is 8-16; the number of secondary hydrogen spray guns is 8-12; the number of tertiary hydrogen spray guns is 8-16, and nozzles are arranged at their outlets.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] (1) This burner uses ammonia as the main fuel and a small amount of hydrogen as an auxiliary fuel to achieve stable carbon-free combustion.

[0022] (2) Hydrogen fuel, ammonia fuel and combustion-supporting air are all delivered in three stages. Each stage of ammonia fuel has corresponding hydrogen fuel to support its combustion. Therefore, the stable combustion and burnout of ammonia will be greatly improved, making up for the defect of its own poor combustion characteristics.

[0023] (3) The first-level swirl wind has a strong swirl flow, which increases the combustion intensity of the central flame and lays a foundation for the stable combustion of the burner; the second-level swirl wind has a weak swirl flow, which moderately suppresses the combustion intensity and lengthens the flame, which is beneficial to suppressing the formation of nitrogen oxides; the third-level direct current wind isolates the third-level fuel from the central flame, further lengthens the flame, increases the flame fullness, prevents the flame from concentrating, and suppresses the formation of nitrogen oxides.

[0024] (4) The third-stage hydrogen fuel and ammonia fuel are premixed by injection, combined with a flue gas internal circulation structure design to simultaneously achieve stable combustion and reduce nitrogen oxides. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the throat structure of the hydrogen stable combustion ammonia burner of the present invention.

[0026] Figure 2 It is a three-dimensional schematic diagram of the hydrogen stable combustion ammonia burner of the present invention.

[0027] Figure 3 It is a schematic cross-sectional view of the structure of the hydrogen stable combustion ammonia burner of the present invention.

[0028] Figure 4 It is a partial cross-sectional view of the third-stage fuel gun of the hydrogen stable combustion ammonia burner of the present invention.

[0029] Among them, 1 is the ammonia fuel inlet, 2 is the hydrogen fuel inlet, 3 is the combustion-supporting air inlet, 4 is the first-level hydrogen spray gun, 4-1 is the bowl-shaped stable combustion blunt body, 5 is the second-level hydrogen spray gun, 6 is the third-level hydrogen spray gun, 6-1 is the nozzle, 7 is the first-level ammonia spray gun, 8 is the second-level ammonia spray gun, 9 is the third-level ammonia spray gun, 9-1 is the gas mixing section, 10 is the first-level cyclone, 11 is the second-level cyclone, 12 is the DC air interlayer, 13 is the high-energy ignition rod installation opening, 14 is the fire viewing mirror installation opening, 15 is the flame detector installation opening, 16 is the ammonia fuel gas collecting ring, 17 is the hydrogen fuel gas collecting ring, 18 is the burner shell, 19 is the burner back plate, and 20 is the DC air cylinder. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below with reference to the accompanying drawings.

[0031] Example

[0032] refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 The hydrogen stable combustion ammonia burner of this embodiment includes, from the center to the outside, a coaxially arranged primary hydrogen spray gun 4, a primary cyclone 10, a primary ammonia spray gun 7, a secondary cyclone 11, a secondary hydrogen spray gun 5, a secondary ammonia spray gun 8, a direct current wind interlayer 12, a tertiary hydrogen spray gun 6, and a tertiary ammonia spray gun 9. Ammonia fuel enters the ammonia gas collecting ring 16 from the ammonia fuel inlet 1, and hydrogen fuel enters the hydrogen gas collecting ring 17 from the hydrogen fuel inlet 2, and each realizes three-stage fuel through spray guns designed from different radial positions.

[0033] The first-level ammonia spray gun 7 is located in the first-level cyclone 10, and the end face of the first-level ammonia spray gun 7 is flush with the swirl blades on the first-level cyclone 10 to maintain the swirl effect to the greatest extent. The number of the first-level ammonia spray guns 7 can be set to 4-6 according to actual conditions; the second-level ammonia spray gun 8 is located in the second-level cyclone 11, and the end face of the second-level ammonia spray gun is flush with the swirl blades of the second-level cyclone 11 to maintain the swirl effect to the greatest extent. The number of the second-level ammonia spray guns 8 can be set to 8-12 according to actual conditions; the third-level ammonia spray gun 9 is located between the DC air interlayer 12 and the burner casing 18, and the number of the third-level ammonia spray guns 9 can be set to 8-16 according to actual conditions.

[0034] The first-stage hydrogen spray gun 4 is located in the center; the second-stage hydrogen spray gun 5 is located in the second-stage cyclone 11, and the end face of the second-stage hydrogen spray gun 5 is flush with the swirl blade of the second-stage cyclone 11 to maximize the swirl effect. The number of the second-stage hydrogen spray guns 5 can be set to 8-12 according to actual conditions; the third-stage hydrogen spray gun 6 is located between the DC air interlayer 12 and the burner casing 18, and the number of the third-stage hydrogen spray guns 6 can be set to 8-16 according to actual conditions.

[0035] A "bowl-shaped guide blunt body" 4-1 is designed at the outlet of the first-stage hydrogen spray gun 4. Inside the first-stage hydrogen spray gun 4, the curved surface of the "bowl bottom" not only reduces the flow resistance, but also has a guide effect, so that the central hydrogen is evenly sprayed out to the surrounding in a ring shape, thereby mixing more fully with the first-stage swirl wind and the first-stage ammonia fuel, which is conducive to the stable establishment of the central flame; outside the spray gun, the plane of the "bowl mouth" forms a micro negative pressure reflux zone, which draws in part of the flame and high-temperature flue gas to achieve the effect of anchoring the central flame.

[0036] The secondary hydrogen spray gun 5 and the secondary ammonia spray gun 8 are arranged alternately in the secondary cyclone 11; the tertiary hydrogen spray gun 6 and the tertiary ammonia spray gun 9 are arranged in a coaxial sleeve type.

[0037] After the tertiary hydrogen spray gun 6 takes in gas through the hydrogen fuel collecting ring 17, it changes direction to be coaxially arranged with the tertiary ammonia spray gun 9; the outlet of the tertiary hydrogen spray gun 6 is 15-25 cm away from the outlet of the tertiary ammonia spray gun 9, and this length area is used as the gas mixing section 9-1. The nozzle 6-1 is designed at the outlet of the tertiary hydrogen spray gun 6; after the hydrogen is accelerated and ejected from the nozzle 6-1, the surrounding ammonia is sucked in, thereby achieving preliminary mixing of hydrogen-ammonia fuel in the gas mixing section 9-1, which is of great help in improving the combustion characteristics of the third-stage ammonia.

[0038] After the air enters through the combustion-supporting air inlet 3, it is finally divided into three levels to support combustion: the first-level combustion-supporting air is delivered by the first-level cyclone 10, which plays a role in central combustion stabilization. Therefore, the first-level cyclone 10 is designed with strong swirl, the blade angle is 45°-60°, and the number of blades is 8-12; the second-level combustion-supporting air is delivered by the second-level cyclone 11, which ensures the mixing of fuel and air while also ensuring the length of the flame. Therefore, the second-level cyclone 11 is designed with weak swirl, the blade angle is 30°-45°, and the number of blades is 16-24; the third-level combustion-supporting air is delivered by the DC air interlayer 12, which moderately weakens the influence of the swirl on the third-level ammonia spray gun 9, thereby delaying the combustion of part of the fuel, increasing the length and fullness of the flame in the furnace, reducing the combustion intensity, and is beneficial to controlling nitrogen oxide emissions.

[0039] The outlet of the tertiary ammonia spray gun 9 should protrude from the outlet of the burner shell 18 by about 30-50cm. After the ammonia and hydrogen in the gas mixing section 9-1 are mixed, the combustion characteristics of the ammonia have been greatly enhanced. Therefore, exposing this level of nozzle outside the shell not only does not have to face the problem of stable combustion, but the fuel can also be fully mixed with the surrounding flue gas during combustion, forming a local flue gas circulation area, reducing the flame temperature, thereby achieving the effect of reducing nitrogen oxides.

[0040] The first-stage cyclone 10 and the burner back plate 19 reserve a high-energy ignition rod installation opening 13, and the diameter of the high-energy ignition rod installation opening 13 is 25 mm; the second-stage cyclone 11 and the burner back plate 19 reserve a fire-viewing mirror installation opening 14 and a flame detector installation opening 15, and the diameter of the reserved fire-viewing mirror installation opening 14 and the flame detector installation opening 15 is 40 mm.

[0041] It can be seen from the above scheme that the present invention has the following characteristics: (1) This burner uses ammonia as the main fuel, and is assisted by a small amount of hydrogen, which can achieve stable carbon-free combustion. (2) Hydrogen fuel, ammonia fuel, and combustion-supporting air are all introduced in three stages. Each stage of ammonia fuel has a corresponding hydrogen fuel to support its combustion, so the stable combustion and burnout of ammonia will be greatly improved, making up for the defect of its own poor combustion characteristics. (3) The first-level swirl wind has a strong swirl, which improves the combustion intensity of the central flame and lays the foundation for the stable combustion of the burner; the second-level swirl wind has a weak swirl, which moderately suppresses the combustion intensity and lengthens the flame, which is conducive to suppressing the generation of nitrogen oxides; the third-level direct current wind isolates the third-level fuel from the central flame, further lengthens the flame, improves the flame fullness, prevents flame concentration, and suppresses the generation of nitrogen oxides. (4) The third-level hydrogen fuel and ammonia fuel adopt the induced premixing to improve the combustion characteristics, and cooperate with the flue gas internal circulation structure design to achieve stable combustion and reduce nitrogen oxides simultaneously.

[0042] In summary, the present invention realizes the efficient coupling utilization of hydrogen-ammonia fuel through the three-stage design of ammonia fuel, hydrogen fuel, and combustion-supporting air, combined with strong and weak swirl combustion, blunt body stable combustion, fuel injection premixing and flue gas internal circulation technology. In specific implementation, the present invention provides a safe, environmentally friendly and efficient way for a carbon-free combustion system with ammonia as the main gas and hydrogen as the auxiliary gas, which can create significant social benefits. The burner has the characteristics of high stable combustion, high burnout, low emissions, and wide fuel adaptability. The burner of the present invention can use ammonia as the main fuel, and at the same time use a small amount of hydrogen as a stable combustion fuel as an auxiliary, which can greatly improve the combustion characteristics of ammonia while saving precious hydrogen resources.

Claims

1. A hydrogen stable combustion ammonia burner, characterized in that: The invention comprises a burner housing (18) and a DC air cylinder (20), wherein the DC air cylinder (20) is coaxially arranged in the inner cavity of the burner housing (18), and the DC air cylinder (20) is coaxially provided with a first-level hydrogen spray gun (4), a first-level cyclone (10) and a second-level cyclone (11), wherein the first-level cyclone (10) and the second-level cyclone (11) are arranged at the outlet end of the DC air cylinder (20), the first-level hydrogen spray gun (4) is located at the axis of the DC air cylinder (20), the first-level cyclone (10) is sleeved on the outlet end of the first-level hydrogen spray gun (4), and the second-level cyclone (11) is sleeved on the outer ring of the first-level cyclone (10); the outer edge of the second-level cyclone (11) is aligned with the inner wall of the DC air cylinder (20). A preset distance is provided between the first-stage hydrogen spray gun (4) and a DC air layer (12) is formed therebetween; a plurality of first-stage ammonia spray guns (7) are evenly distributed around the first-stage hydrogen spray gun (4), and the outlet of the first-stage ammonia spray gun (7) is located at the outlet of the first-stage cyclone (10); a plurality of second-stage hydrogen spray guns (5) and second-stage ammonia spray guns (8) are evenly arranged around the first-stage ammonia spray gun (7) around the first-stage hydrogen spray gun (4), and the second-stage hydrogen spray guns (5) and the second-stage ammonia spray guns (8) are arranged alternately; a plurality of third-stage ammonia spray guns (9) are evenly distributed in the annular cavity between the DC air cylinder (20) and the burner housing (18), and a third-stage hydrogen spray gun (6) is coaxially arranged in the inner cavity of each third-stage ammonia spray gun (9); The outlet end surface of the first-stage ammonia spray gun (7) is flush with the swirl blades of the first-stage cyclone (10) through which it passes; The outlet end face of the secondary hydrogen spray gun (5) is flush with the swirl blades of the secondary cyclone (11) through which it passes, and the outlet end face of the secondary ammonia spray gun (8) is flush with the swirl blades of the secondary cyclone (11) through which it passes.

2. A hydrogen combustion-stable ammonia burner according to claim 1, characterized in that: A bowl-shaped flow-guiding bluff body (4-1) is provided at the outlet of the first-stage hydrogen spray gun (4); the bowl bottom of the bowl-shaped flow-guiding bluff body (4-1) is a smooth curved surface; the bowl bottom of the bowl-shaped flow-guiding bluff body (4-1) is located inside the first-stage hydrogen spray gun (4); and the bowl mouth of the bowl-shaped flow-guiding bluff body (4-1) is located outside the outlet of the first-stage hydrogen spray gun (4).

3. A hydrogen combustion-stable ammonia burner according to claim 1, characterized in that: The outlet of the three-stage hydrogen spray gun (6) is located 15-25 cm upwind of the outlet of the three-stage ammonia spray gun (9), and the outlet of the three-stage hydrogen spray gun (6) is located between the outlets of the three-stage ammonia spray gun (9) to form a fuel gas mixing section (9-1).

4. A hydrogen stable combustion ammonia burner according to claim 1, characterized in that: The outlet of the three-stage ammonia spray gun (9) extends out from the outlet end of the burner housing (18) by a distance of 30-50 cm.

5. A hydrogen combustion stable ammonia burner according to claim 1, characterized in that: The outlet of the first-stage hydrogen spray gun (4), the first-stage cyclone (10) and the second-stage cyclone (11) are all located inside the outlet of the DC air cylinder (20).

6. A hydrogen combustion-stable ammonia burner according to claim 1, characterized in that: The swirl intensity of the first-stage cyclone (10) is stronger than the swirl intensity of the second-stage cyclone (11).

7. A hydrogen combustion-stable ammonia burner according to claim 6, characterized in that: The blade angle of the first-stage cyclone (10) is 45°-60°, and the number of blades is 8-12; the blade angle of the second-stage cyclone (11) is 30°-45°, and the number of blades is 16-24.

8. A hydrogen combustion-stable ammonia burner according to claim 6, characterized in that: An ammonia fuel inlet (1), an ammonia fuel gas collecting ring (16), a hydrogen fuel inlet (2), a hydrogen fuel gas collecting ring (17) and a combustion-supporting air inlet (3) are provided on the burner casing (18); the combustion-supporting air inlet (3) is connected to the DC air cylinder (20); the ammonia fuel inlet (1) is connected to the fuel gas collecting ring (16); the first-stage ammonia spray gun (7), the second-stage ammonia spray gun (8) and the third-stage ammonia spray gun (9) are all connected to the ammonia fuel gas collecting ring (16); the hydrogen fuel inlet (2) is connected to the hydrogen fuel gas collecting ring (17); the first-stage hydrogen spray gun (4), the second-stage hydrogen spray gun (5) and the third-stage hydrogen spray gun (6) are all connected to the hydrogen fuel gas collecting ring (17); The swirl blades of the first-stage swirler (10) are provided with a high-energy ignition rod mounting opening (13); the swirl blades of the second-stage swirler (11) are provided with a fire-viewing mirror mounting opening (14) and a flame detector mounting opening (15); The number of the first-stage ammonia spray guns (7) is 4-6; the number of the second-stage ammonia spray guns (8) is 8-12; the number of the third-stage ammonia spray guns (9) is 8-16; the number of the second-stage hydrogen spray guns (5) is 8-12; the number of the third-stage hydrogen spray guns (6) is 8-16, and the nozzles (6-1) are arranged at the outlets of the third-stage hydrogen spray guns (6).

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