Multi-stage air distribution turbulent burner for coal-ammonia co-combustion

Abstract

The invention discloses a multi-stage air distribution turbulent burner for coal and ammonia co-combustion. The multi-stage air distribution turbulent burner comprises an ignition gun, an air pipe and an ammonia gas conveying pipe. An ignition sleeve is sleeved outside the ignition gun; the multiple air pipes are arranged outside the ignition sleeve in a sleeving mode one by one; air conveying channels are respectively formed between the adjacent air pipes and between the ignition sleeve and the adjacent air pipes; the conveying directions of all the air pipes are the same, and the outlet ends of all the air pipes are flush. And the ammonia gas conveying pipes are in multiple stages, and different stages of ammonia gas conveying pipes are communicated with different air pipes. The multi-stage air distribution turbulent burner for coal-ammonia co-combustion is provided with a plurality of air pipes and a plurality of stages of ammonia gas conveying pipes, multi-stage air distribution can be carried out, ammonia gas is mixed into air in a multi-stream air flow mode, staged supply of the ammonia gas and the air is achieved, combustion conditions are optimized, generation of combustion type NOx is reduced, and the combustion efficiency is improved. Therefore, the emission amount of nitrogen oxide in the combustion process of ammonia is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of clean coal combustion, and more specifically to a multi-stage air distribution swirl burner for coal-ammonia mixed combustion. Background Art

[0002] Among existing technologies, using off-peak green electricity to produce hydrogen and ammonia is one of the more mature energy storage measures. Ammonia (NH3) is easier to liquefy and store than hydrogen, and has mature production, storage and transportation infrastructure. In the power industry, using green ammonia to partially replace traditional coal-fired power generation is an effective way to reduce carbon emissions, promote the consumption of renewable energy, drive the growth of the hydrogen energy industry, and achieve carbon neutrality.

[0003] The main obstacle to the direct use of ammonia in the combustion system is that it will cause a large amount of NOx emissions during the combustion process. Therefore, for those skilled in the art, how to effectively reduce the nitrogen oxide emissions during the combustion of ammonia is a problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0004] In view of this, the present invention provides a multi-stage air distribution swirl burner for coal-ammonia mixed combustion, which is provided with multiple air ducts and multi-stage ammonia delivery pipes, capable of multi-stage air distribution, and allowing ammonia to be mixed into the wind in the form of multiple airflows, thereby realizing the staged supply of ammonia and air, optimizing combustion conditions, reducing the generation of combustion-type NOx, and thus effectively reducing the emission of nitrogen oxides from ammonia during the combustion process.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A multi-stage air distribution swirl burner for coal-ammonia mixed combustion, comprising:

[0007] An ignition gun, wherein the ignition gun is provided with an ignition sleeve;

[0008] There are multiple air ducts, and each of the air ducts is sleeved outside the ignition sleeve. Air delivery channels are formed between adjacent air ducts and between the ignition sleeve and adjacent air ducts. The air delivery directions of the air ducts are the same, and the outlet ends of the air ducts are flush.

[0009] The ammonia delivery pipe is multi-level, and ammonia delivery pipes of different levels are connected to different air ducts.

[0010] Optionally, in the above-mentioned multi-stage air distribution swirl burner, the number of stages N of the ammonia gas delivery pipes is less than the number M of the air delivery channels; the ammonia gas delivery pipes at each stage are connected to different air ducts step by step from the center to the periphery, wherein the first-stage ammonia gas delivery pipe is connected to the central air duct located in the central area.

[0011] Optionally, in the above-mentioned multi-stage air distribution swirl burner, in all the air ducts, the outlets of the air ducts connected to the ammonia delivery pipe are provided with swirl blades.

[0012] Optionally, in the above-mentioned multi-stage air distribution swirl burner, among all the air ducts, the outlet of the N+1th air duct from the center to the periphery is also provided with a swirl blade, and the swirl formed by the swirl blade is opposite to the swirl direction formed by the swirl blade at the outlet of the air duct connected to the ammonia delivery pipe.

[0013] Optionally, in the above-mentioned multi-stage air distribution swirl burner, the air duct includes a central air duct, a primary air duct, a secondary air duct, and a tertiary air duct from the center to the periphery; the central air duct is a straight duct; the inlet section of the primary air duct is bent; the secondary air duct and the tertiary air duct are straight ducts, and the ends of the two opposite to the outlet are sealed; the sides of the secondary air duct and the tertiary air duct are respectively connected to the secondary air introduction duct and the tertiary air introduction duct;

[0014] The ammonia gas delivery pipe includes a primary ammonia gas delivery pipe inserted into the inlet of the central air duct, and a secondary ammonia gas delivery pipe connected to the side of the primary air duct.

[0015] Optionally, in the above-mentioned multi-stage air distribution swirl burner, a central wind swirl blade is provided at the outlet of the central air duct, and the central wind swirl blade is installed on the ignition sleeve; a primary wind swirl blade is provided at the outlet of the primary air duct, and the primary wind swirl blade is installed on the central air duct; a secondary wind swirl blade is provided at the outlet of the secondary air duct, and the secondary wind swirl blade is installed on the primary air duct.

[0016] Optionally, in the above-mentioned multi-stage air distribution swirl burner, the central air swirl blade forms an angle of 30° to 45° with the cross section of the central air duct; the primary air swirl blade forms an angle of 45° to 60° with the cross section of the central air duct;

[0017] The secondary air swirl blades have opposite tangential rotation directions and opposite radial rotation directions to those of the primary air swirl blades.

[0018] Optionally, in the above-mentioned multi-stage air distribution swirl burner, when the ammonia blending ratio of the multi-stage air distribution swirl burner is lower than 15%, the ammonia flow rate in the first-level ammonia delivery pipe accounts for 50% to 60% of the total ammonia flow rate; when the ammonia blending ratio of the multi-stage air distribution swirl burner is greater than 15%, the ammonia flow rate in the first-level ammonia delivery pipe accounts for 20 to 40% of the total ammonia flow rate.

[0019] Optionally, in the above-mentioned multi-stage air distribution swirl burner, in the air delivered by the multi-stage air distribution swirl burner, the central air of the central air duct accounts for 15-17%, the primary air delivered by the primary air duct accounts for 25-30%, the secondary air delivered by the secondary air duct accounts for 30-35%, and the tertiary air delivered by the tertiary air duct accounts for 18-30%.

[0020] Optionally, in the above-mentioned multi-stage air distribution swirl burner, the central air duct, the primary air duct, the secondary air duct and the tertiary air duct are an integrated structure.

[0021] The present invention provides a multi-stage air distribution swirl burner for coal-ammonia mixed combustion, comprising an ignition gun, an air duct and an ammonia delivery pipe; an ignition sleeve is sleeved outside the ignition gun; there are multiple air ducts, which are sleeved outside the ignition sleeve one by one; air delivery channels are formed between adjacent air ducts, and between the ignition sleeve and adjacent air ducts respectively; the delivery directions of the air ducts are the same, and the outlet ends of the air ducts are flush; the ammonia delivery pipe is multi-stage, and ammonia delivery pipes of different stages are connected to different air ducts.

[0022] The above-mentioned multi-stage air distribution swirl burner for coal-ammonia mixed combustion is equipped with multiple air ducts and multi-stage ammonia delivery pipes, which can perform multi-stage air distribution and allow ammonia to be mixed into the wind in the form of multiple airflows, thereby realizing the staged supply of ammonia and air, optimizing combustion conditions, and reducing the generation of combustion-type NOx, thereby effectively reducing the emission of nitrogen oxides from ammonia during the combustion process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic diagram of the main structure of a multi-stage air distribution swirl burner for coal-ammonia co-firing provided in an embodiment of the present invention;

[0025] Figure 2 for Figure 1 The right side view of the multi-stage air distribution swirl burner used for coal-ammonia co-firing is shown;

[0026] in, Figure 1-Figure 2 middle:

[0027] Ignition gun 1; ignition sleeve 2; primary ammonia delivery pipe 3; central air duct 4; primary air duct 5; secondary ammonia delivery pipe 6; secondary air introduction pipe 7; tertiary air introduction pipe 8; central air swirl blade 9; primary air swirl blade 10; secondary air swirl blade 11; secondary air duct 12; tertiary air duct 13. DETAILED DESCRIPTION

[0028] The embodiment of the present invention discloses a multi-stage air distribution swirl burner for coal-ammonia mixed combustion, which is provided with multiple air ducts and multi-stage ammonia delivery pipes, capable of multi-stage air distribution, and allowing ammonia to be mixed into the wind in the form of multiple airflows, thereby realizing the staged supply of ammonia and air, optimizing combustion conditions, reducing the generation of combustion-type NOx, and thus effectively reducing the emission of nitrogen oxides from ammonia during the combustion process.

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] See also Figure 1-Figure 2 The embodiment of the present invention provides a multi-stage air distribution swirl burner for coal-ammonia mixed combustion, comprising an ignition gun 1, an air duct and an ammonia delivery pipe; an ignition sleeve 2 is sleeved on the outside of the ignition gun 1; there are multiple air ducts, which are sleeved on the outside of the ignition sleeve 2 one by one; air delivery channels are formed between adjacent air ducts, and between the ignition sleeve 2 and adjacent air ducts respectively; the delivery directions of the air ducts are the same, and the outlet ends of the air ducts are flush; the ammonia delivery pipe is multi-stage, and ammonia delivery pipes of different stages are connected to different air ducts.

[0031] The above-mentioned multi-stage air distribution swirl burner for coal-ammonia co-firing is equipped with multiple air ducts and multi-stage ammonia delivery pipes, which can perform multi-stage air distribution and allow ammonia to be mixed into the wind in the form of multiple airflows, thereby realizing the staged supply of ammonia and air, facilitating the full mixing of ammonia and airflow to optimize combustion conditions, reduce the generation of combustion-type NOx, and thus effectively reduce the emission of nitrogen oxides from ammonia during the combustion process.

[0032] In one embodiment, the number of stages N of ammonia gas delivery pipes is less than the number M of air delivery channels; each stage of ammonia gas delivery pipes is connected to different air ducts step by step from the center to the periphery, wherein the first stage ammonia gas delivery pipe 3 is connected to the central air duct 4 located in the central area. In a specific embodiment, N is set to be 1 less than M.

[0033] In this embodiment, ammonia is transported by multiple air ducts located in the center, so that ammonia is prevented from being too close to the inner wall of the combustion chamber after being sprayed into the combustion chamber by the burner, and ammonia is prevented from being directly discharged from the combustion chamber with the flue gas without being burned, thereby improving the utilization rate of ammonia. At the same time, ammonia is transported by multiple air ducts located in the center, ensuring that ammonia is in an area with greater air flow disturbance, which is conducive to improving the mixing uniformity of ammonia and air flow.

[0034] In a further trial scheme, among all the air ducts, the outlet of the air duct connected to the ammonia delivery pipe is provided with a swirl blade. Among all the air ducts, the outlet of the N+1th air duct from the center to the periphery is also provided with a swirl blade, and the swirl formed by the swirl blade is opposite to the swirl direction formed by the swirl blade at the outlet of the air duct connected to the ammonia delivery pipe.

[0035] Specifically, the air ducts from the center to the periphery include a central air duct 4, a primary air duct 5, a secondary air duct 12, and a tertiary air duct 13; the central air duct 4 is a straight pipe; the inlet section of the primary air duct 5 is bent; the secondary air duct 12 and the tertiary air duct are respectively straight pipes, and the ends of both opposite to the outlets are sealed; the sides of the secondary air duct 12 and the tertiary air duct 13 are respectively connected to the secondary air introduction pipe 7 and the tertiary air introduction pipe 8; the ammonia delivery pipe includes a primary ammonia delivery pipe 3 inserted at the inlet of the central air duct 4, and a secondary ammonia delivery pipe 6 connected to the side of the primary air duct 5.

[0036] The central air duct 4 is used to transport air and ammonia; the primary air duct 5 is used to transport air, pulverized coal, and ammonia; the secondary air duct 12 and the tertiary air duct 13 are used to transport air respectively. The primary ammonia delivery pipe 3 can be set as a nozzle for spraying ammonia into the central air duct 4, and the number of the primary ammonia delivery pipes 3 can be set to multiple and evenly distributed in the central air duct 4 along the circumferential direction, so as to facilitate the sprayed ammonia and the air in the central air duct 4 to be evenly mixed.

[0037] The primary air duct 5 includes the bent inlet section and a main body section connected to the inlet section, the main body section is sleeved outside the central air duct 4, and the secondary air duct 12 is sleeved outside the main body section of the primary air duct 5. The ignition sleeve 2, the central air duct 4, the main body section of the primary air duct 5, the secondary air duct 12 and the tertiary air duct 13 are coaxially arranged.

[0038] A central wind swirl blade 9 is provided at the outlet of the central air duct 4, and the central wind swirl blade 9 is installed on the ignition sleeve 2; a primary wind swirl blade 10 is provided at the outlet of the primary air duct 5, and the primary wind swirl blade 10 is installed on the central air duct 4; a secondary air swirl blade 11 is provided at the outlet of the secondary air duct 12, and the secondary air swirl blade 11 is installed on the primary air duct 5.

[0039] The secondary air swirl blades 11 have opposite tangential and radial rotation directions to the primary air swirl blades 10. The tangential rotation direction refers to the direction of movement of the fluid along the circumferential direction under the action of the swirl blades in a plane perpendicular to the axis of rotation; the radial rotation direction refers to the direction of movement of the fluid along the radius of the center of rotation (i.e., from the center of the circle outward) under the action of the swirl blades. This embodiment does not limit the inclination of the primary air swirl blades 11 and the secondary air swirl blades 10. It is only necessary to ensure that the swirl formed at the secondary air swirl blades 11 and the swirl formed at the primary air swirl blades 10 are in opposite directions. The swirl formed by the primary air swirl blades 10 has the same direction as the swirl formed by the central air swirl blades 9.

[0040] In the solution provided in this embodiment, ammonia is mixed in two streams, one part of ammonia is fed in through the primary ammonia delivery pipe 3, mixed with the central air, and then enters the furnace after passing through the central air axial swirl blades, and the other part of ammonia is fed in through the secondary ammonia delivery pipe 6, mixed with the primary air, and then enters the furnace after passing through the primary air swirl blades 10. Ammonia is mixed in two streams to ensure the optimal mixing ratio under different mixing and combustion conditions.

[0041] The wind delivered by the central air duct 4, the primary air duct 5 and the secondary air duct 12, under the action of the swirl blades, causes the air, ammonia and coal powder to mix rapidly and rotate at high speed, forming a low-pressure area in the center area of ​​the furnace, and then forming an axisymmetric high-temperature low-oxygen double-annular recirculation area at the burner outlet, sucking and igniting the ammonia introduced from the central air duct 4, strengthening the mixing of ammonia with the primary air and coal powder, strengthening the reducing atmosphere in the rich combustion area, and inhibiting the generation of NOx. In addition, the air, ammonia and coal powder rotate at high speed under the action of the swirl blades and form a good mixing effect in the furnace, promoting the full combustion of coal and ammonia, and reducing the generation of pollutants and harmful gases.

[0042] The secondary air rotates after passing through the secondary air swirl blades 11, and the negative pressure area formed by the expansion of the secondary air pipe 12 can also make the high-temperature flue gas in the furnace reflux. The refluxed high-temperature flue gas can provide enough heat to stably ignite the fuel. In specific applications, the swirl intensity can be adjusted by adjusting the angle of the secondary air swirl blades 11, and the ratio of the secondary air to the tertiary air can be adjusted according to the blending ratio to achieve burner air grading, thereby obtaining the best combustion, which can prevent the overall combustion process from being carried out under the equivalent ratio condition, and suppress the generation of NOx during the combustion process, so as to achieve the purpose of reducing NOx emissions.

[0043] The central air swirl blade 9 forms an angle of 30° to 45° with the cross section of the central air duct 4; the primary air swirl blade 10 forms an angle of 45° to 60° with the cross section of the central air duct 4. By changing the blade inclination angle of the swirl blade, the swirl intensity of the airflow can be adjusted to meet the requirements of different loads and ammonia blending ratios.

[0044] When the ammonia blending ratio of the multi-stage air distribution swirl burner is lower than 15%, the ammonia flow rate in the first-level ammonia delivery pipe 3 accounts for 50% to 60% of the total ammonia flow rate; when the ammonia blending ratio of the multi-stage air distribution swirl burner is greater than 15%, the ammonia flow rate in the first-level ammonia delivery pipe 3 accounts for 20% to 40% of the total ammonia flow rate.

[0045] In the air delivered by the multi-stage air distribution swirl burner, the central air delivered by the central air duct 4 accounts for 15-17%, the primary air delivered by the primary air duct 5 accounts for 25-30%, the secondary air delivered by the secondary air duct 12 accounts for 30-35%, and the tertiary air delivered by the tertiary air duct 13 accounts for 18-30%.

[0046] When used, the flow rates of ammonia and air in the central air and primary air can be manually adjusted according to the changes in the ammonia blending ratio, thereby achieving a dynamically optimized combustion state.

[0047] In the above-mentioned multi-stage air distribution swirl burner, the central air duct 4, the primary air duct 5, the secondary air duct 12, the tertiary air duct 13, the secondary air introduction pipe 7 and the tertiary air introduction pipe 8 are an integrated structure.

[0048] The multi-stage air distribution swirl burner provided in this embodiment has a compact structure, is easy to maintain, occupies a small space, and is convenient for installation and daily inspection. In addition, the multi-stage air distribution swirl burner for coal-ammonia mixed combustion provided in this embodiment can be applied to industries such as electricity and metallurgy, especially in situations where it is necessary to reduce emissions and improve energy utilization, and has a good market prospect.

[0049] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0050] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-stage air distribution swirl burner for coal-ammonia mixed combustion, characterized in that: include: An ignition gun, wherein the ignition gun is provided with an ignition sleeve; There are multiple air ducts, and each of the air ducts is sleeved outside the ignition sleeve. Air delivery channels are formed between adjacent air ducts and between the ignition sleeve and adjacent air ducts. The air delivery directions of the air ducts are the same, and the outlet ends of the air ducts are flush. The ammonia delivery pipe is multi-level, and ammonia delivery pipes of different levels are connected to different air ducts.

2. The multi-stage air distribution swirl burner according to claim 1, characterized in that: The number N of stages of the ammonia gas delivery pipes is less than the number M of the air delivery channels; the ammonia gas delivery pipes of each stage are connected to different air ducts step by step from the center to the periphery, wherein the first-stage ammonia gas delivery pipe is connected to the central air duct located in the central area.

3. The multi-stage air distribution swirl burner according to claim 2, characterized in that: In all the air ducts, the outlets of the air ducts connected to the ammonia delivery pipes are provided with swirl blades.

4. The multi-stage air distribution swirl burner according to claim 3, characterized in that: Among all the air ducts, the outlet of the N+1th air duct from the center to the periphery is also provided with a swirl blade, and the swirl formed by the swirl blade is opposite to the swirl direction formed by the swirl blade at the outlet of the air duct connected to the ammonia delivery pipe.

5. The multi-stage air distribution swirl burner according to claim 4, characterized in that: The air duct includes a central air duct, a primary air duct, a secondary air duct, and a tertiary air duct from the center to the periphery; the central air duct is a straight duct; the inlet section of the primary air duct is bent; the secondary air duct and the tertiary air duct are straight ducts, and the ends of the two opposite to the outlet are sealed; the sides of the secondary air duct and the tertiary air duct are connected to the secondary air introduction duct and the tertiary air introduction duct respectively; The ammonia gas delivery pipe includes a primary ammonia gas delivery pipe inserted into the inlet of the central air duct, and a secondary ammonia gas delivery pipe connected to the side of the primary air duct.

6. The multi-stage air distribution swirl burner according to claim 5, characterized in that: A central wind swirl blade is provided at the outlet of the central air duct, and the central wind swirl blade is installed on the ignition sleeve; a primary wind swirl blade is provided at the outlet of the primary air duct, and the primary wind swirl blade is installed on the central air duct; a secondary wind swirl blade is provided at the outlet of the secondary air duct, and the secondary wind swirl blade is installed on the primary air duct.

7. The multi-stage air distribution swirl burner according to claim 6, characterized in that: The central wind swirl blade forms an angle of 30° to 45° with the cross section of the central air duct; the primary wind swirl blade forms an angle of 45° to 60° with the cross section of the central air duct; The secondary air swirl blades have opposite tangential rotation directions and opposite radial rotation directions to those of the primary air swirl blades.

8. The multi-stage air distribution swirl burner according to claim 5, characterized in that: When the ammonia blending ratio of the multi-stage air distribution swirl burner is lower than 15%, the ammonia flow rate in the first-level ammonia delivery pipe accounts for 50% to 60% of the total ammonia flow rate; when the ammonia blending ratio of the multi-stage air distribution swirl burner is greater than 15%, the ammonia flow rate in the first-level ammonia delivery pipe accounts for 20% to 40% of the total ammonia flow rate.

9. The multi-stage air distribution swirl burner according to claim 5, characterized in that: In the air delivered by the multi-stage air distribution swirl burner, the central air of the central air duct accounts for 15-17%, the primary air delivered by the primary air duct accounts for 25-30%, the secondary air delivered by the secondary air duct accounts for 30-35%, and the tertiary air delivered by the tertiary air duct accounts for 18-30%.

10. The multi-stage air distribution swirl burner according to claim 5, characterized in that: The central air duct, the primary air duct, the secondary air duct and the tertiary air duct are an integrated structure.

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