SCR (Selective Catalytic Reduction) denitration ammonia spraying system

Abstract

The invention discloses an SCR denitration ammonia spraying system, and relates to the technical field of SCR denitration, the SCR denitration ammonia spraying system comprises a plurality of ammonia spraying assemblies and a plurality of flow dividing assemblies in one-to-one correspondence with the ammonia spraying assemblies, the ammonia spraying assemblies are installed on a first supporting frame, and the flow dividing assemblies are installed on a second supporting frame. The spraying direction of the ammonia gas is in the same direction as the flowing direction of the flue gas, so that local non-uniformity caused by impact and turbulent flow between two gas flows is avoided, and the mixing effect of the ammonia gas and the flue gas is jointly improved by arranging the plurality of shunting assemblies.

Description

Technical Field

[0001] The invention relates to the technical field of SCR denitration, and in particular to an SCR denitration ammonia injection system. Background Art

[0002] During the SCR denitrification process of boiler flue gas, the uniformity of the mixture of ammonia / air and flue gas is one of the key factors affecting the denitrification efficiency. At present, the mainstream ammonia injection device for boiler flue gas SCR denitrification is the ammonia injection grid. Spray holes are set on the horizontal tubes that make up the grid. Although it can achieve a certain ammonia injection effect, there are also some obvious problems: 1. The pressure and flow rate of each nozzle are not equal, and the mixing uniformity of ammonia / air mixed gas and flue gas is poor; 2. After long-term operation, the nozzle is prone to clogging; 3. Since the NOx emission value is unstable during boiler operation, excessive ammonia escape is prone to occur. Summary of the invention

[0003] The object of the present invention is to provide an SCR denitration ammonia injection system to solve the above-mentioned multiple defects caused by the prior art.

[0004] To achieve the above object, the present invention provides the following technical solution: an SCR denitration ammonia injection system, comprising a plurality of ammonia injection components and a plurality of flow diversion components corresponding to the ammonia injection components one by one, the ammonia injection components are installed on a support frame 1, and the flow diversion components are installed on a support frame 2; The ammonia injection assembly comprises a floating gas collecting pipe and a nozzle, and the ammonia gas sprayed from the nozzle is discharged to the flow dividing assembly via the floating gas collecting pipe and is divided and diffused by the flow dividing assembly; The ammonia spray component can move toward the diversion component, and when the ammonia spray component contacts the diversion component and continues to move, the floating air collecting pipe can compress the air collecting cavity in the ammonia spray component and generate an air flow to be sprayed to the nozzle to clean the dust clogging the nozzle, and the excess ammonia in the ammonia spray component will flow to the recovery component through the diversion component for recycling.

[0005] Furthermore, it also includes an air intake component, which includes an air intake box and a plurality of air intake branch pipes. The air intake box is installed at the air intake end of one of the ammonia injection components. The plurality of air intake branch pipes are respectively connected to the ammonia injection components and can input ammonia into the ammonia injection components.

[0006] Further, the ammonia injection assembly includes an inner pipe, an outer pipe and a floating gas collecting pipe; The outer tube is installed on the outer periphery of the inner tube and one end is closed. The floating gas collecting pipe is slidably connected in the gap between the outer tube and the inner tube to form an air collecting cavity. A return spring is sleeved in the air collecting cavity. The nozzle is installed on one end of the inner tube. A plurality of circumferentially arranged backblowing nozzles are arranged on the side wall of the inner tube near the nozzle.

[0007] Furthermore, the flow splitter assembly comprises a base, a flow splitter sheet and a truncated cone-shaped flow splitter seat, a plurality of the flow splitters are circumferentially welded to one end of the base, and the flow splitter seat is fixed to the other end of the base and faces the ammonia injection assembly; The base and the diversion seat are provided with a through diversion airway and are connected to the recovery component.

[0008] Furthermore, the base is a circular tubular structure and a sealing plug is provided at one end of the base, and the diverter seat is a hollow shell structure and is integrally connected to the base.

[0009] Furthermore, the recovery component includes a recovery box and a return pipe, and the recovery box is connected to a plurality of bases respectively by means of a plurality of return pipes.

[0010] Furthermore, one of the ammonia injection components is located at the geometric center of the remaining ammonia injection components, and the remaining ammonia injection components are circumferentially arranged around the ammonia injection component at the geometric center.

[0011] Furthermore, the recovery box is coaxially arranged with the ammonia spraying assembly at the geometric center.

[0012] Furthermore, the support frame 1 and the support frame 2 have the same structural composition, both including a main ring member located in the center, a plurality of secondary ring members located on the periphery of the main ring member, and spokes connecting the main ring member and the secondary ring members.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention is provided with a plurality of independent nozzles, and the ammonia gas spraying direction is in the same direction as the flue gas flow direction, so as to avoid the impact and turbulence between the two airflows causing local unevenness, and the plurality of diversion components are provided to jointly improve the mixing effect of ammonia gas and flue gas.

[0014] 2. The present invention also provides a floating gas collecting pipe, which can compress the gas collecting cavity in the ammonia spraying component and generate air flow to spray to the nozzle to clean the dust attached to the nozzle when blocked by the diversion component, thereby reducing the probability of nozzle blockage.

[0015] 3. The ammonia injection component in the present invention can also cooperate with the diversion component to throttle the excess ammonia and recycle it through the recovery component, thereby reducing the phenomenon of excessive ammonia escape. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the present invention.

[0017] Figure 2 It is the front view of the present invention.

[0018] Figure 3 It is a schematic diagram of the connection between the ammonia spraying assembly and the support frame 1 in the present invention.

[0019] Figure 4 It is a schematic diagram of the relative positions of the ammonia injection component, the diversion component and the recovery component in the present invention.

[0020] Figure 5 It is a schematic diagram of the present invention being assembled into a boiler pipe.

[0021] in: 1 Ammonia spray assembly, 10 Inner pipe, 11 Outer pipe, 12 Floating collecting pipe, 13 Return spring, 14 Limiting ring, 15 Collecting chamber, 16 Backflush nozzle, 2 Diverter assembly, 20 Base, 21 Diverter plate, 22 Diverter seat, 23 Sealing plug, 3 Inlet assembly, 30 Inlet box, 31 Inlet branch pipe, 4 Recovery assembly, 40 Recovery box, 41 Return pipe, 42 Diverter air duct, 5 Support frame 1, 6 Support frame 2, 7 Auxiliary support frame, 8 Nozzle. DETAILED DESCRIPTION

[0022] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0023] See also Figures 1 to 5 , the present invention provides a technical solution: An SCR denitrification ammonia injection system includes a plurality of ammonia injection components 1, a plurality of diverter components 2 corresponding one to the ammonia injection components 1, and an air intake component 3 connected to the ammonia injection components 1. The ammonia injection components 1 are mounted on a support frame 1 5, and the diverter components 2 are mounted on a support frame 2 6. The support frame 1 5 and the support frame 2 6 have the same structural composition, and both include a main ring component located in the center, a plurality of secondary ring components located on the periphery of the main ring component, and a spoke plate connecting the main ring component and the secondary ring component.

[0024] The ammonia injection assembly 1 includes an inner tube 10, an outer tube 11 and a floating gas collecting pipe 12. The ammonia gas sprayed from the nozzle 8 is discharged to the flow dividing assembly 2 via the floating gas collecting pipe 12 and is diverted by the flow dividing assembly 2. The length of the inner tube 10 is greater than that of the outer tube 11, and the inner tube 10 located on one side of the air intake assembly 3 has an installation space for assembly with the support frame 1 5. The outer tube 11 is installed on the outer periphery of the inner tube 10 and one end is closed. The floating gas collecting pipe 12 is slidably connected in the gap between the outer tube 11 and the inner tube 10 to form a gas collecting chamber 15. A return spring 13 is sleeved in the gas collecting chamber 15. A limit ring 14 is also provided on the inner wall of the outer tube 11 for limiting the range of movement of the floating gas collecting pipe 12. The nozzle 8 is installed on one end of the inner tube 10. A plurality of circumferentially arranged backblowing nozzles 16 are provided on the side wall of the inner tube 10 near the nozzle 8. A vent hole connected to the gas collecting chamber 15 is also provided on the outer tube 11. The flow splitter assembly 2 includes a base 20, a flow splitter sheet 21 and a truncated cone-shaped flow splitter seat 22. A plurality of the flow splitters 21 are circumferentially welded to one end of the base 20. The number of the flow splitters 21 is an even number, and 6 are provided in the present invention. The flow splitter seat 22 is fixed to the other end of the base 20 and faces the ammonia injection assembly 1.

[0025] The ammonia spray component 1 can move toward the diversion component 2, and when the ammonia spray component 1 contacts the diversion component 2 and continues to move, the floating air collecting pipe 12 can compress the air collecting chamber 15 in the ammonia spray component 1 and generate an airflow to be sprayed to the nozzle 8 to clean the dust blocking the nozzle 8, and the excess ammonia in the ammonia spray component 1 will flow through the diversion component 2 to the recovery component 4 for recycling. The recovery component 4 includes a recovery box 40 and a reflux pipe 41, and the recovery box 40 is connected to multiple bases 20 respectively by means of multiple reflux pipes 41.

[0026] The air intake assembly 3 includes an air intake box 30 and a plurality of air intake branch pipes 31. The air intake box 30 is installed at the air intake end of one of the ammonia injection assemblies 1. Specifically, the air intake box 30 is installed at the air intake end of the ammonia injection assembly 1 located at the center. The plurality of air intake branch pipes 31 are respectively connected to the ammonia injection assemblies 1 and can input ammonia into the ammonia injection assembly 1.

[0027] In this embodiment, the base 20 and the diverter seat 22 are provided with a through diverter airway 42 and connected to the recovery component 4. Specifically, the base 20 is a circular tubular structure and a sealing plug 23 is provided at one end of the base 20. The diverter seat 22 is a hollow shell structure and is integrally connected to the base 20.

[0028] In this embodiment, one of the ammonia injection components 1 is located at the geometric center of the remaining ammonia injection components 1, and the remaining ammonia injection components 1 are circumferentially arranged around the ammonia injection component 1 at the geometric center. Specifically, the recovery box 40 is coaxially arranged with the ammonia injection component 1 at the geometric center.

[0029] In the present invention, an auxiliary support frame 7 is also installed on one side of the support frame 1 5 and the support frame 2 6, so that the ammonia spray assembly 1 and the diversion assembly 2 can be installed in the boiler pipeline, and the auxiliary support frame 7 connected to the support frame 1 5 can move along the boiler pipeline under the action of the corresponding driving device.

[0030] The working process and principle of the present invention are as follows: Under normal conditions, the floating gas header 12 in the ammonia injection assembly 1 is at a distance from the flow diversion seat 22 in the flow diversion assembly 2. The ammonia gas sprayed from the nozzle 8 passes through the inner tube 10 and the floating gas header 12 and is sprayed to the flow diversion seat 22 and is diverted by the flow diversion assembly 2 to the entire boiler pipeline and is fully mixed with the gas in the pipeline. When the sensor at the front end of the SCR denitration system detects that the NOx emission value in the pipeline has significantly decreased, due to the hysteresis of the throttling adjustment of the nozzle 8, the excess ammonia will be released and temporarily gathered in the space formed by the inner tube 10 and the floating gas collecting pipe 12. When the throttling adjustment of the nozzle 8 is in place, the driving device is started and the ammonia injection component 1 moves toward the diverter component 2 until the floating gas collecting pipe 12 contacts the diverter seat 22. The excess ammonia gathered in the inner tube 10 and the floating gas collecting pipe 12 will flow to the recovery component 4 through the diverter component 2 for recycling; The ammonia spray assembly 1 continues to move, and the floating air collecting pipe 12 compresses the air collecting chamber 15 in the ammonia spray assembly 1 and generates an air flow to be sprayed to the nozzle 8 to clean the dust attached to the nozzle 8.

[0031] Based on the above, the present invention is provided with a plurality of independent nozzles 8, and the ammonia spraying direction is in the same direction as the flue gas flow direction, so as to avoid the impact and turbulence between the two airflows causing local unevenness, and the plurality of diversion components 2 are provided to jointly improve the mixing effect of ammonia and flue gas; the present invention is also provided with a floating gas collecting pipe 12, which can compress the gas collecting cavity 15 in the ammonia spraying component 1 when blocked by the diversion component 2 and generate an airflow to be sprayed to the nozzle 8 to clean the dust blocked at the nozzle 8, thereby reducing the probability of nozzle 8 being blocked; the ammonia spraying component 1 in the present invention can also cooperate with the diversion component 2 to throttle the excess ammonia and recycle it through the recovery component 4, thereby reducing the phenomenon of excessive ammonia escape.

[0032] It is known from common technical knowledge that the present invention can be implemented by other embodiments that do not deviate from its spirit or essential features. Therefore, the above disclosed embodiments are only illustrative in all respects and are not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are included in the present invention.

Claims

1. An SCR denitration ammonia injection system, characterized in that: It comprises a plurality of ammonia spraying components (1) and a plurality of flow diversion components (2) corresponding one to the ammonia spraying components (1), wherein the ammonia spraying components (1) are mounted on a first support frame (5), and the flow diversion components (2) are mounted on a second support frame (6); The ammonia injection assembly (1) comprises a floating gas collecting pipe (12) and a nozzle (8); the ammonia gas sprayed from the nozzle (8) is discharged to the flow dividing assembly (2) via the floating gas collecting pipe (12) and is diverted and diffused by the flow dividing assembly (2); The ammonia spray component (1) is capable of moving toward the diverter component (2), and when the ammonia spray component (1) contacts the diverter component (2) and continues to move, the floating air collecting pipe (12) is capable of compressing the air collecting chamber (15) in the ammonia spray component (1) and generating an air flow to be sprayed to the nozzle (8) to clean the dust blocking the nozzle (8), and the excess ammonia in the ammonia spray component (1) will flow through the diverter component (2) to the recovery component (4) for recycling.

2. The SCR denitration ammonia injection system according to claim 1, characterized in that: The invention also comprises an air intake component (3), wherein the air intake component (3) comprises an air intake box (30) and a plurality of air intake branch pipes (31), wherein the air intake box (30) is installed at the air intake end of one of the ammonia injection components (1), and the plurality of air intake branch pipes (31) are respectively connected to the ammonia injection components (1) and are capable of inputting ammonia into the ammonia injection component (1).

3. The SCR denitration ammonia injection system according to claim 1, characterized in that: The ammonia injection assembly (1) comprises an inner pipe (10), an outer pipe (11) and a floating gas collecting pipe (12); The outer tube (11) is mounted on the outer periphery of the inner tube (10) and one end is closed; the floating gas collecting pipe (12) is slidably connected in the gap between the outer tube (11) and the inner tube (10) to form a gas collecting cavity (15); a return spring (13) is sleeved in the gas collecting cavity (15); the nozzle (8) is mounted on one end of the inner tube (10); and a plurality of circumferentially arranged back-blowing nozzles (16) are provided on the side wall of the inner tube (10) near the nozzle (8).

4. The SCR denitration ammonia injection system according to claim 1, characterized in that: The flow splitter assembly (2) comprises a base (20), a flow splitter sheet (21) and a truncated cone-shaped flow splitter seat (22); a plurality of the flow splitters (21) are circumferentially welded to one end of the base (20); and the flow splitter seat (22) is fixed to the other end of the base (20) and faces the ammonia injection assembly (1); The base (20) and the diverter seat (22) are provided with a through diverter air passage (42) and are connected to the recovery component (4).

5. The SCR denitration ammonia injection system according to claim 4, characterized in that: The base (20) is a circular tubular structure and a sealing plug (23) is provided at one end of the base (20); the flow divider (22) is a hollow shell structure and is integrally connected to the base (20).

6. The SCR denitration ammonia injection system according to claim 4, characterized in that: The recovery component (4) comprises a recovery box (40) and a return pipe (41); the recovery box (40) is connected to a plurality of bases (20) respectively by means of a plurality of return pipes (41).

7. The SCR denitration ammonia injection system according to claim 6, characterized in that: One of the ammonia injection components (1) is located at the geometric center of the remaining ammonia injection components (1), and the remaining ammonia injection components (1) are arranged circumferentially around the ammonia injection component (1) at the geometric center.

8. The SCR denitration ammonia injection system according to claim 7, characterized in that: The recovery box (40) is coaxially arranged with the ammonia spraying assembly (1) at the geometric center.

9. The SCR denitration ammonia injection system according to claim 7, characterized in that: The support frame 1 (5) and the support frame 2 (6) have the same structural composition, both comprising a main ring member located in the center, a plurality of secondary ring members located on the periphery of the main ring member, and a spoke plate connecting the main ring member and the secondary ring members.

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