A denitration spraying system for a waste incineration boiler

Abstract

The utility model discloses a kind of garbage incineration boiler denitration spray systems, comprising: first spray gun, second spray gun and K-type thermocouple, first spray gun and second spray gun are connected to urea solution supply system and compressed air supply system by pipeline;Multiple first spray guns are respectively arranged on the upper portion of the two side walls of incineration boiler second passage along horizontal direction, multiple second spray guns extend to the upper portion of second passage after penetrating the ceiling of incineration boiler second passage along vertical direction, and first spray gun and second spray gun are on the same horizontal plane, to form the spray curtain wall that covers the cross section of second passage;Multiple K-type thermocouples are respectively arranged between adjacent two first spray guns and adjacent two second spray guns, to monitor the flue gas temperature near first spray gun and second spray gun in real time.The utility model has the characteristics of compact structure, simple principle and high stability, enhances the mixing degree of urea solution and flue gas, and vertically arranged spray gun does not bend due to self-weight under high temperature.

Description

Technical Field

[0001] This utility model relates to the field of waste incineration treatment, specifically to a denitrification spray system for a waste incineration boiler. Background Technology

[0002] Currently, the denitrification technologies used in waste incineration plants mainly focus on post-incineration flue gas denitrification, such as selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR). Compared with SCR denitrification technology, SNCR injects a denitrifying agent into the appropriate temperature window of the first flue gas duct of the incinerator to reduce NO. x Furthermore, it does not require a catalyst, thus avoiding engineering problems such as catalyst blockage or poisoning. It has lower investment and maintenance costs and is widely used in industries such as power, cement, and waste incineration.

[0003] SNCR (Selective Non-Catalytic Reduction) is a technology that uses ammonia or urea, an amino-based reducing agent, injected into the boiler furnace at temperatures ranging from 850°C to 1000°C without the use of a catalyst to remove nitrogen oxides (NOx) from the flue gas. x SNCR (Non-Standardized Reduction) technology reduces nitrogen (N2) and water (H2O) to nitrogen gas and water, respectively. The denitrification efficiency of SNCR technology is generally between 30% and 60%, with the specific efficiency depending on various factors, including reaction temperature, the amount of NH3 and NO. x The stoichiometry, degree of mixing, and reaction time, etc.

[0004] Existing technologies primarily involve arranging spray guns in the first channel of a waste incineration boiler, using different layers of spray guns to meet the needs of different temperature ranges. For example, Chinese patent CN212974711U discloses a urea layered injection system that can improve SNCR denitrification efficiency. This system mainly improves denitrification efficiency by arranging three layers of spray guns in the first channel. However, since the denitrification reaction cannot proceed effectively when the temperature in the first channel of the furnace exceeds the optimal reaction temperature, simply arranging spray guns in the first channel is insufficient to meet the denitrification requirements.

[0005] Currently, for many large-scale waste incinerators, as the calorific value of waste gradually increases, the temperature of the boiler's first channel also rises, with the temperature at the top of the first channel exceeding 1000℃. At this point, introducing urea into the first channel for denitrification exceeds its optimal reaction temperature range, resulting in low denitrification efficiency and high nitrogen oxide content in the flue gas emissions. Furthermore, due to the improper arrangement of urea spray guns (generally placed around the furnace walls), the urea solution cannot fully mix with the flue gas in the center of the furnace, leading to poor denitrification performance.

[0006] Chinese patent CN207680335U discloses a waste incinerator flue gas denitrification system, including a waste incinerator. The flue gas from the waste incinerator is directed to a waste heat boiler via a flue. The flue is divided into a first flue, a second flue, and a third flue. The first flue is a rectangular flue, and at least three rows of spray guns are respectively arranged on the three side walls of the rectangular flue. Because the urea spray guns are basically fixed to the furnace wall, the urea spray cannot penetrate deep into the center of the furnace, resulting in low SNCR denitrification efficiency.

[0007] Chinese patent CN222586108U discloses an SNCR denitrification spray system for a waste incineration boiler. This system primarily uses urea spray guns arranged on the side and rear walls of the second channel. However, the urea spray guns on the side walls cannot penetrate deeply into the center of the furnace. If the urea spray gun extends too far laterally into the furnace, it is prone to bending at high temperatures, making it impossible to retract. Utility Model Content

[0008] The technical problem to be solved by this utility model is to overcome the above-mentioned shortcomings of the prior art and provide a waste incineration boiler denitrification spray system that is simple in principle, convenient to operate, highly stable in operation, and has a long service life.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: A denitrification spray system for a waste incineration boiler includes: a first spray gun, a second spray gun, and K-type thermocouples. Both the first and second spray guns are connected to a urea solution supply system and a compressed air supply system via pipes. Multiple first spray guns are arranged horizontally on the upper part of two side walls of a second channel of the incineration boiler, and multiple second spray guns extend vertically through the ceiling of the second channel to the upper part of the second channel. The nozzles of the multiple first spray guns and the multiple second spray guns are all on the same horizontal plane to form a spray curtain covering the cross-section of the second channel. Multiple K-type thermocouples are arranged between two adjacent first spray guns and two adjacent second spray guns to monitor the flue gas temperature near the first and second spray guns in real time.

[0010] As a further improvement of this utility model, both the first spray gun and the second spray gun are connected to a mixer through a liquid delivery pipe. The mixer is respectively connected to a pipe with a soft water regulating valve and a pipe with a urea solution regulating valve, so as to achieve uniform mixing of soft water and urea solution before delivery to the first spray gun and the second spray gun.

[0011] As a further improvement of this utility model, the first spray gun includes a first fluid delivery pipe, a first nozzle, a first compressed air inlet, and a first urea solution inlet; the rear end of the first fluid delivery pipe is provided with a first compressed air inlet and a first urea solution inlet, and the front end of the first fluid delivery pipe is provided with a conical first nozzle to spray out a conical urea solution spray.

[0012] As a further improvement of this utility model, two first spray guns are arranged on each of the two side walls.

[0013] As a further improvement of this utility model, the distance between the first spray gun and the end of the side wall is d1, and the distance between the two first spray guns is d2, where d1∶d2=1.5~2.0∶1.

[0014] As a further improvement of this utility model, the second spray gun includes a second fluid delivery pipe, a second nozzle, a second compressed air inlet and a second urea solution inlet. The rear end of the second fluid delivery pipe is provided with a second compressed air inlet and a second urea solution inlet, and the front end of the second fluid delivery pipe is evenly distributed with a plurality of conical second nozzles to spray out a circular urea solution spray.

[0015] As a further improvement of this utility model, the ceiling of the second channel is provided with two second spray guns.

[0016] As a further improvement of this utility model, the distance between the second spray gun and the end of the side wall is d3, and the distance between the two second spray guns is d4, where d3∶d4=2.0~2.5∶1.

[0017] As a further improvement of this utility model, the distance between the second spray gun and the rear wall of the second channel is d5, where d5∶d4=0.9~1.1∶1.

[0018] As a further improvement of this utility model, the urea solution supply system, the compressed air supply system and the K-type thermocouple are all electrically connected to an external DCS controller. The K-type thermocouple is used to feed back the temperature information in the second channel to the DCS controller in real time. When the temperature in the second channel is higher than the preset denitrification reaction temperature, the DCS controller controls the urea solution supply system and the compressed air supply system to stop operating, and the first spray gun and the second spray gun exit the second channel.

[0019] Compared with the prior art, the advantages of this utility model are: This utility model discloses a denitrification spray system for a waste incineration boiler. By employing a combination of spray guns arranged on the side wall and ceiling of the second channel, the side wall uses conical spray urea spray guns that spray urea forward from the furnace wall, while the ceiling uses circular spray urea spray guns that extend vertically downward into the furnace for urea denitrification. This allows the flue gas and urea in the center of the furnace to mix thoroughly. Furthermore, the vertical downward arrangement of the spray guns effectively prevents them from bending and deforming under high temperature and gravity, thus extending their service life. Attached Figure Description

[0020] Figure 1 This is a top view schematic diagram of the denitrification spray system for a waste incineration boiler in a specific embodiment of this utility model; Figure 2 This is a side view schematic diagram of the denitrification spray system for a waste incineration boiler in a specific embodiment of this utility model; Figure 3 This is a schematic diagram of the arrangement of the first spray gun on the side wall in a specific embodiment of this utility model; Figure 4 This is a schematic diagram showing the arrangement of the second spray gun in the second channel in a specific embodiment of this utility model; Figure 5 This is a schematic diagram of the structural principle of the first spray gun in a specific embodiment of this utility model; Figure 6 This is a schematic diagram of the structural principle of the second spray gun in a specific embodiment of this utility model; Figure 7 This is a schematic diagram of the structural principle of the front end of the second spray gun in a specific embodiment of this utility model.

[0021] Legend: 1. First spray gun; 11. First fluid delivery pipe; 12. First nozzle; 13. First compressed air inlet; 14. First urea solution inlet; 15. Fixed flange; 2. Second spray gun; 21. Second fluid delivery pipe; 22. Second nozzle; 23. Second compressed air inlet; 24. Second urea solution inlet; 25. Limiting ring; 3. K-type thermocouple; 4. Soft water regulating valve; 5. Urea solution regulating valve; 6. Liquid delivery pipe; 7. Compressed air pipe; 8. Mixer; 100. First channel; 200. Second channel; 201. Side wall; 202. Rear wall; 300. Incinerator; 301. Feed inlet; 302. Slag outlet; 400. Horizontal flue. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0023] In the description of this utility model, it should be understood that the terms "side", "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "multiple" means two or more, unless otherwise explicitly specified.

[0025] Example like Figure 2 As shown, in the waste incineration system, the incinerator 300 has a feed inlet 301 at its input end. Waste enters the incinerator 300 through the feed inlet 301 for incineration. The flue gas generated by waste incineration flows sequentially through the first channel 100, the second channel 200, and the horizontal flue 400, and then is discharged. The ash generated by waste incineration is discharged through the ash outlet 302 at the bottom of the incinerator 300.

[0026] like Figure 1 and Figure 2As shown, the denitrification spray system for a waste incineration boiler of this utility model includes: a first spray gun 1, a second spray gun 2, and a K-type thermocouple 3. Both the first spray gun 1 and the second spray gun 2 are dual-fluid spray guns, and both are connected to a urea solution supply system and a compressed air supply system via pipelines. The urea solution supply system and the compressed air supply system are conventional in the art and will not be described in detail here. Multiple first spray guns 1 are arranged horizontally on the upper part of the two side walls 201 of the second channel 200 of the incineration boiler, and multiple second spray guns 2 extend vertically through the ceiling of the second channel 200 to the upper part of the second channel 200. The two side walls 201 use short-stroke urea spray guns, and the ceiling uses long-stroke urea spray guns. The long-stroke urea spray guns can extend into the furnace and are at the same horizontal level as the short-stroke urea spray guns on the side walls 201, forming a spray curtain covering the cross-section of the second channel 200. During operation, the compressed air for atomization is maintained at approximately 0.7 MPa. To ensure the spraying effect and spraying distance of the urea spray gun, the solution flow rate of a single spray gun is not less than 50 L / h. Multiple K-type thermocouples 3 are respectively arranged between two adjacent first spray guns 1 and two adjacent second spray guns 2 to monitor the flue gas temperature near the first spray guns 1 and second spray guns 2 in real time.

[0027] like Figure 1 As shown, both the first spray gun 1 and the second spray gun 2 are connected to the mixer 8 via liquid delivery pipes 6. The mixer 8 is connected to pipes with soft water regulating valves 4 and urea solution regulating valves 5, respectively, to ensure that soft water and urea solution are mixed evenly before being delivered to the first spray gun 1 and the second spray gun 2. Both the first spray gun 1 and the second spray gun 2 are connected to the compressed air supply system via compressed air pipes 7. In this embodiment, the mixing ratio of urea solution and soft water is adjusted by regulating the opening of the soft water regulating valve 4 and the urea solution regulating valve 5, respectively. After the urea solution and soft water are mixed evenly, they are mixed with compressed air and then introduced into the spray guns, ultimately sprayed into the second channel 200 in the form of a mist. The concentration of urea solution introduced into the furnace can be adjusted in real time through the soft water regulating valve 4 and the urea solution regulating valve 5 to ensure the quality of flue gas denitrification.

[0028] like Figure 5 As shown, the first spray gun 1 is a short-range urea spray gun with a length of 0.1m, including a first fluid delivery pipe 11, a first nozzle 12, a first compressed air inlet 13, and a first urea solution inlet 14. The first compressed air inlet 13 and the first urea solution inlet 14 are located at the rear end of the first fluid delivery pipe 11, and a conical first nozzle 12 is located at the front end of the first fluid delivery pipe 11 to spray a conical spray of urea solution. A fixing flange 15 is provided on the outside of the first spray gun 1 to facilitate the installation and fixing of the first spray gun 1.

[0029] like Figure 1 and Figure 3As shown, two first spray guns 1 are arranged on each of the two side walls 201. The distance between the first spray gun 1 and the end of the side wall 201 is d1, and the distance between the two first spray guns 1 is d2, where d1∶d2=1.5∶1.

[0030] like Figure 6 and Figure 7 As shown, the second spray gun 2 is a 2m long-stroke urea spray gun, including a second fluid delivery pipe 21, a second nozzle 22, a second compressed air inlet 23, and a second urea solution inlet 24. The second fluid delivery pipe 21 has a second compressed air inlet 23 and a second urea solution inlet 24 at its rear end, and four conical second nozzles 22 are evenly distributed at its front end to spray a circular urea solution mist. A limiting ring 25 is provided on the outside of the second spray gun 2 to adjust the depth of the second spray gun 2 extending into the second channel 200. The second spray gun 2 extends vertically into the furnace from the top of the second channel 200, enhancing the mixing degree of urea solution and flue gas. Furthermore, the vertically arranged second spray gun 2 will not bend due to its own weight at high temperatures, improving the safety and reliability of the spray gun operation.

[0031] like Figure 1 and Figure 4 As shown, two second spray guns 2 are arranged side-by-side on the ceiling of the second channel 200. The distance between the second spray gun 2 and the end of the side wall 201 is d3, and the distance between the two second spray guns 2 is d4, where d3:d4 = 2.2:1. The distance between the second spray gun 2 and the rear wall 202 of the second channel 200 is d5, where d5:d4 = 1:1. By determining the interval between the spray guns and the interval between the spray guns and the wall, a spray section covering the cross-section of the second channel 200 can be formed with the fewest spray guns, avoiding spray dead zones.

[0032] In this embodiment, considering that the degree of mixing between flue gas and urea spray is closely related to the denitrification efficiency, spray guns are arranged on both the side walls 201 and the ceiling of the second channel 200. At the same time, based on the spray width and the size of the furnace cavity, the arrangement scheme of two spray guns on each side wall and two spray guns on the ceiling is determined, which improves the denitrification efficiency, reduces the nitrogen oxide content in the flue gas, and is beneficial to environmental protection.

[0033] In this embodiment, the urea solution supply system, compressed air supply system, and K-type thermocouple 3 are all electrically connected to an external DCS controller. The K-type thermocouple 3 is used to feed back the temperature information in the second channel 200 to the DCS controller in real time. When the flue gas temperature in the second channel 200 is in the range of 850℃ to 1000℃, the urea spray gun can be engaged. When the flue gas temperature in the second channel 200 is higher than the preset denitrification reaction temperature, the DCS controller controls the urea solution supply system and compressed air supply system to stop operating, and the first spray gun 1 and the second spray gun 2 are withdrawn from the second channel 200. The spray guns are inserted into the furnace when needed and withdrawn from the furnace when not in use to prevent burnout.

[0034] In this embodiment, urea spray guns are arranged at a suitable temperature window in the furnace. A total of six urea spray guns are arranged in the upper part of the second channel 200 of the incinerator, with four urea spray guns arranged on the side walls and two on the ceiling. Three K-type thermocouples 3 are also arranged to monitor the temperature field in the upper part of the second channel 200. The two urea spray guns on the ceiling extend into the furnace to perform denitrification, ensuring that the flue gas and urea solution are fully mixed in the center of the furnace, thereby improving the denitrification efficiency. By performing denitrification in the suitable temperature field of the second channel 200, the denitrification efficiency will reach more than 60%, controlling the emission of nitrogen oxides in the flue gas to within 100 mg / m³, while ensuring that the ammonia escape is controlled within 4 mg / m³.

[0035] The above description is merely a preferred embodiment of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are protected. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within the protection scope of this utility model.

Claims

1. A denitrification spray system for a waste incineration boiler, characterized in that, include: The first spray gun (1), the second spray gun (2), and the K-type thermocouple (3) are connected to the urea solution supply system and the compressed air supply system through pipes. Multiple first spray guns (1) are arranged horizontally on the upper part of the two side walls (201) of the second channel (200) of the incinerator. Multiple second spray guns (2) extend vertically through the roof of the second channel (200) of the incinerator and to the upper part of the second channel (200). The nozzles of multiple first spray guns (1) and multiple second spray guns (2) are all on the same horizontal plane to form a spray curtain covering the cross section of the second channel (200). Multiple K-type thermocouples (3) are arranged between two adjacent first spray guns (1) and two adjacent second spray guns (2) to monitor the flue gas temperature near the first spray guns (1) and the second spray guns (2) in real time.

2. The denitrification spray system for a waste incineration boiler according to claim 1, characterized in that, The first spray gun (1) and the second spray gun (2) are both connected to the mixer (8) through the liquid delivery pipe (6). The mixer (8) is connected to the pipe with the soft water regulating valve (4) and the pipe with the urea solution regulating valve (5) respectively, so as to achieve the uniform mixing of soft water and urea solution before delivery to the first spray gun (1) and the second spray gun (2).

3. The denitrification spray system for a waste incineration boiler according to claim 2, characterized in that, The first spray gun (1) includes a first fluid delivery pipe (11), a first nozzle (12), a first compressed air inlet (13) and a first urea solution inlet (14); the first fluid delivery pipe (11) is provided with a first compressed air inlet (13) and a first urea solution inlet (14) at its rear end, and a conical first nozzle (12) is provided at its front end to spray out a conical urea solution spray.

4. The denitrification spray system for a waste incineration boiler according to claim 3, characterized in that, Two first spray guns (1) are arranged on each of the two side walls (201).

5. The denitrification spray system for a waste incineration boiler according to claim 4, characterized in that, The distance between the first spray gun (1) and the end of the side wall (201) is d1, and the distance between the two first spray guns (1) is d2, where d1:d2 = 1.5 to 2.0:

1.

6. The denitrification spray system for a waste incineration boiler according to claim 2, characterized in that, The second spray gun (2) includes a second fluid delivery pipe (21), a second nozzle (22), a second compressed air inlet (23), and a second urea solution inlet (24). The second fluid delivery pipe (21) has a second compressed air inlet (23) and a second urea solution inlet (24) at its rear end. The second fluid delivery pipe (21) has multiple conical second nozzles (22) evenly distributed at its front end to spray out a circular urea solution spray.

7. The denitrification spray system for a waste incineration boiler according to claim 6, characterized in that, The ceiling of the second channel (200) is equipped with two second spray guns (2).

8. The denitrification spray system for a waste incineration boiler according to claim 7, characterized in that, The distance between the second spray gun (2) and the end of the side wall (201) is d3, and the distance between the two second spray guns (2) is d4, where d3:d4 = 2.0 to 2.5:

1.

9. The denitrification spray system for a waste incineration boiler according to claim 8, characterized in that, The distance between the second spray gun (2) and the rear wall (202) of the second channel (200) is d5, d5∶d4=0.9~1.1∶1.

10. The denitrification spray system for a waste incineration boiler according to any one of claims 1 to 9, characterized in that, The urea solution supply system, compressed air supply system and K-type thermocouple (3) are all electrically connected to an external DCS controller. The K-type thermocouple (3) is used to feed back the temperature information in the second channel (200) to the DCS controller in real time. When the temperature in the second channel (200) is higher than the preset denitrification reaction temperature, the DCS controller controls the urea solution supply system and compressed air supply system to stop operating, and the first spray gun (1) and the second spray gun (2) exit the second channel (200).

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