Ammonia injection device

Abstract

The utility model relates to a boiler technical field, it is a kind of ammonia injection device, it is applied to boiler, including first spray pipe, first ammonia injection subassembly, second ammonia injection subassembly and first air inlet pipe, and the first spray pipe is spaced apart to be located in the smoke inlet channel of boiler several.Because the utility model is reasonable in structure and compact, by setting connecting plate, so that first spray head is located above first spray pipe, avoid first spray head blockage after blocking the air outlet hole of front air outlet pipe, also like this can avoid the phenomenon that first spray head is difficult to disassemble with front air outlet pipe after blocking, first spray head makes the ammonia gas that flows out from air outlet hole evenly spray into the smoke inlet channel of boiler, make ammonia gas and flue gas fully mix, and evenly mixed ammonia gas and flue gas can effectively reduce the ammonia escape rate of SCR export, by optimization and transformation, can improve the overall performance of SCR, reduce ammonia escape concentration, prevent air preheater blockage, reduce reducing agent consumption, reduce fan power consumption, improve the safe and economic stable operation level of unit.

Description

Technical Field

[0001] This utility model relates to the field of boiler technology and is an ammonia injection device. Background Technology

[0002] Currently, boiler denitrification adopts the high-ash flue gas denitrification (SCR) process. Each boiler is equipped with two SCR reactors. In the SCR reactor, ammonia-containing gas needs to be injected into the flue gas to be treated through an ammonia injection device. The ammonia-containing gas is usually a mixture of ammonia and air. The ammonia injection device is usually an ammonia injection grid, which is mainly composed of several parallel spray pipes. Several nozzles are regularly distributed on the spray pipes. The ammonia supply main pipe for sending ammonia-containing gas is connected to each spray pipe through several inlet pipes. The ammonia-containing gas is sent into the spray pipes, and then the ammonia-containing gas is sprayed out from the nozzles, mixed with the flue gas in the flue, and enters the denitrification reactor together for denitrification reaction.

[0003] The currently used ammonia injection grid requires manual adjustment of each ammonia injection pipe when adjusting the appropriate ammonia injection flow rate. Due to the significant reduction in nitrogen oxide emission control values ​​and the substantial decrease in the allowable range of pollutant fluctuations, especially when boiler operating conditions change, the existing manual control precision is insufficient, resulting in large fluctuations in nitrogen oxides at the desulfurization outlet, which affects the safe and stable operation of the unit.

[0004] Uneven distribution of nitrogen oxide concentration at the inlet, coupled with the continuous length of the spray pipes (i.e., the length of the spray pipes inside the boiler is the same as the width of the flue gas inlet channel) and nozzles positioned along the length of the spray pipes, results in a reduced ammonia injection rate at nozzles located at the far end of the spray pipes. This leads to a lag in ammonia injection rate adjustment, causing ammonia escape. Ammonia then reacts with sulfur trioxide to form ammonium bisulfate and viscous substances. This significant increase in ammonia escape substantially raises the operating costs of the denitrification system. Furthermore, increased ammonia escape leads to higher maintenance and repair costs, increased fan power consumption, and seriously affects the safe and stable operation of the unit.

[0005] Uneven flue gas flow field washes over the catalyst module. Dust and ammonium bisulfate in the flue gas are adsorbed onto the cathode wire and anode plate of the electrostatic precipitator, which reduces the electrostatic removal efficiency. Liquid contact increases the viscosity of the slurry, and the slurry sticks to the surface of the demister blades, which is difficult to wash off, causing demister blockage and seriously affecting the stable operation of the environmental protection equipment. Summary of the Invention

[0006] This utility model provides an ammonia injection device that overcomes the shortcomings of the prior art. It can effectively solve the problems of easy clogging of the nozzles in the existing ammonia injection grid of the boiler, and the impact of clogging on the amount of ammonia injected into the boiler.

[0007] The technical solution of this utility model is achieved through the following measures: An ammonia injection device, applied to a boiler, includes a first injection pipe, a first ammonia injection assembly, a second ammonia injection assembly, and a first air inlet pipe. Several first injection pipes are spaced apart in the boiler's flue gas inlet channel. The left and right ends of each first injection pipe are fixedly installed to the inner side of the boiler's flue gas inlet channel. Several first ammonia injection assemblies are spaced apart on the outer side of the front part of each first injection pipe. Each first ammonia injection assembly includes a front outlet pipe, a connecting plate, and a first nozzle. Several front-end-closed front outlet pipes are fixedly connected to the outer side of the front part of the first injection pipe at intervals. A first injection assembly is fixedly installed on the outer side of the upper part of the first injection pipe corresponding to the position of each front outlet pipe. There is a connecting plate, the front part of which is located above the front of the front exhaust pipe. A first nozzle is provided on the upper side of the front part of the connecting plate. An exhaust hole with internal and external communication is provided on the upper outer side of the front exhaust pipe corresponding to the position of the first nozzle. A second ammonia injection assembly is provided on the rear outer side of the first nozzle at the left position of each front exhaust pipe. The second ammonia injection assembly has the same structure as the first ammonia injection assembly. A first air inlet pipe with a closed right end is fixedly installed on the inner side of the boiler's flue gas passage at the position above each first nozzle. The left end of each first air inlet pipe is sealed and passes through the left side of the boiler's flue gas passage and is located on the left side of the boiler. A first connecting pipe is fixedly connected between the lower outer side of the first air inlet pipe and the upper outer side of the corresponding front exhaust pipe.

[0008] The following are further optimizations and / or improvements to the above-mentioned utility model technical solution: The aforementioned first nozzle may include a base and a guide plate. The base includes several partition plates evenly distributed along the circumference. The lower side of one partition plate is fixedly installed together with the upper front side of the connecting plate. A guide plate is fixedly installed on the upper side of each partition plate. All the guide plates are distributed in a spiral shape. A front air outlet hole with internal and external communication is provided on the upper front side of the front air outlet pipe corresponding to the position of the front side of the connecting plate.

[0009] Several fixing plates can be fixedly installed on the outside of the aforementioned front exhaust pipe at intervals on the left and right. The upper part of each fixing plate is fixedly installed together with the first intake pipe. The leftmost fixing plate and the rightmost fixing plate are fixedly installed together with the inside of the boiler's flue gas inlet channel.

[0010] A second nozzle can be provided between each pair of adjacent first nozzles. The second nozzle has the same structure as the first nozzle. A first fixing hole that runs through the left side of the rear part of the fixing plate corresponding to the position behind each first nozzle is provided. The outer side of the second nozzle and the inner side of the corresponding first fixing hole are fixedly installed together. A third ammonia injection assembly with the same structure as the first ammonia injection assembly is provided on the outer side of the front part of each second nozzle. A fourth ammonia injection assembly with the same structure as the second ammonia injection assembly is provided on the outer side of the rear part of each second nozzle. A second air inlet pipe is provided on the inner side of the boiler's flue gas passage above each second nozzle. The second air inlet pipe has the same structure as the first air inlet pipe. A second fixing hole that runs through the left side of the upper part of the fixing plate corresponding to the position of each first fixing hole is provided. The outer side of the second air inlet pipe and the inner side of the corresponding second fixing hole are fixedly installed together. A second connecting pipe is fixedly connected between the lower outer side of the second air inlet pipe and the upper outer side of the corresponding second nozzle. A regulating valve is installed on the outer side of both the first nozzle and the second nozzle at the left side of the boiler's flue gas passage.

[0011] The aforementioned first connecting pipe may include a first left vertical pipe, a second left vertical pipe, a third left vertical pipe, and a left horizontal pipe with a tubular structure closed at both ends. A first baffle is sealed and fixedly installed on the inner side of the middle of the first nozzle. A second baffle is sealed and fixedly installed on the inner side of the middle of the second nozzle corresponding to the position of the first baffle. The first left vertical pipe and the second left vertical pipe are respectively fixedly connected to the outer side of the upper part of the first nozzle and the second nozzle, respectively, at the position to the left of the first baffle. The upper end of the first left vertical pipe and the upper end of the second left vertical pipe are both fixedly connected to the outer side of the lower part of the left horizontal pipe. A third left vertical pipe is fixedly connected between the upper part of the left horizontal pipe and the outer side of the lower part of the first air inlet pipe. The second connecting pipe includes a first right vertical pipe, a second right vertical pipe, a third right vertical pipe, and a right horizontal pipe with a tubular structure closed at both ends. The first right vertical pipe and the second right vertical pipe are fixedly connected to the upper outer sides of the first nozzle and the second nozzle, respectively, corresponding to the position to the right of the second partition. The upper ends of the first right vertical pipe and the second right vertical pipe are fixedly connected to the lower outer side of the right horizontal pipe. The third right vertical pipe is fixedly connected between the upper part of the right horizontal pipe and the lower outer side of the second air intake pipe.

[0012] This utility model has a reasonable and compact structure. By setting a connecting plate, the first nozzle is positioned above the first spray pipe, which avoids the first nozzle clogging the outlet of the front outlet pipe after it becomes blocked. It also avoids the difficulty of disassembling the first nozzle from the front outlet pipe after it becomes blocked. The first nozzle allows the ammonia gas flowing from the outlet to be evenly injected into the boiler's flue gas inlet channel, so that the ammonia gas and flue gas are fully mixed. The evenly mixed ammonia gas and flue gas can effectively reduce the ammonia slip rate at the SCR outlet. Through optimization and modification, the overall performance of SCR can be improved, the ammonia slip concentration can be reduced, the air preheater can be prevented from clogging, the reducing agent consumption can be reduced, the fan power consumption can be reduced, the service life of the denitrification SCR catalyst can be extended, the efficiency of the air preheater and electrostatic precipitator can be improved, and the safe, economical and stable operation level of the unit can be improved. Attached Figure Description

[0013] Appendix Figure 1 This is a schematic diagram of the front sectional view of the structure of Embodiments 1 to 5 of this utility model when in use.

[0014] Appendix Figure 2 These are schematic diagrams of the main cross-sectional structure of embodiments one to five of this utility model.

[0015] Appendix Figure 3 This is a schematic diagram of the right-side cross-sectional structure of embodiments one to five of this utility model.

[0016] Appendix Figure 4 These are top sectional view structural diagrams of embodiments one to five of this utility model.

[0017] Appendix Figure 5 This is a top view of the front air outlet pipe in embodiments one to five of this utility model.

[0018] Appendix Figure 6 This is a right-side structural schematic diagram of the first nozzle in embodiments two to five of this utility model.

[0019] Appendix Figure 7 This is a top view of the structure of the first nozzle in embodiments two to five of this utility model.

[0020] Appendix Figure 8 This is a three-dimensional structural diagram of the first nozzle in embodiments two to five of this utility model.

[0021] Appendix Figure 9 This is a schematic diagram of the process structure of embodiments one to five of this utility model.

[0022] The codes in the attached diagram are as follows: 1 is the first nozzle, 2 is the front exhaust pipe, 3 is the connecting plate, 4 is the partition plate, 5 is the guide plate, 6 is the exhaust port, 7 is the second ammonia injection assembly, 8 is the first intake pipe, 9 is the fixing plate, 10 is the second nozzle, 11 is the third ammonia injection assembly, 12 is the second intake pipe, 13 is the first left vertical pipe, 14 is the second left vertical pipe, 15 is the third left vertical pipe, 16 is the left horizontal pipe, 17 is the first partition plate, 18 is the second partition plate, 19 is the first right vertical pipe, 20 is the second right vertical pipe, 21 is the third right vertical pipe, 22 is the right horizontal pipe, 23 is the fourth ammonia injection assembly, 24 is the regulating valve, 25 is the boiler, 26 is the flue gas inlet channel, 27 is the ammonia injection branch pipe, and 28 is the ammonia injection main pipe. Detailed Implementation

[0023] This utility model is not limited to the following embodiments, and the specific implementation method can be determined according to the technical solution of this utility model and the actual situation.

[0024] In this utility model, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1 The orientation of the layout is determined by the direction of the map.

[0025] The present invention will be further described below with reference to the embodiments and accompanying drawings: Example 1: As shown in the attached document Figures 1 to 5 As shown, the ammonia injection device is applied to boiler 25 and includes a first injection pipe 1, a first ammonia injection assembly, a second ammonia injection assembly 7, and a first air inlet pipe 8. Several first injection pipes 1 are spaced apart in the flue gas inlet channel 26 of boiler 25. The left and right ends of each first injection pipe 1 are fixedly installed to the inside of the flue gas inlet channel 26 of boiler 25. Several first ammonia injection assemblies are spaced apart on the outer side of the front part of each first injection pipe 1. The first ammonia injection assembly includes a front outlet pipe 2, a connecting plate 3, and a first nozzle. Several front-end-closed front outlet pipes 2 are fixedly connected to the outer side of the front part of the first injection pipe 1 at intervals. A connecting plate 3 is fixedly installed on the outer side of the upper part of each first injection pipe 1 corresponding to the position of the front outlet pipe 2. The front part of the connecting plate 3... Located above the front of the front exhaust pipe 2, a first nozzle is provided on the upper front side of the connecting plate 3. An exhaust hole 6 with internal and external communication is provided on the upper outer side of the front exhaust pipe 2 corresponding to the position of the first nozzle. A second ammonia injection assembly 7 is provided on the rear outer side of the first spray pipe 1 at the left position of each front exhaust pipe 2. The second ammonia injection assembly 7 has the same structure as the first ammonia injection assembly. A first air inlet pipe 8 with a closed right end is fixedly installed on the inner side of the flue gas inlet channel 26 of the boiler 25 at the position above each first spray pipe 1. The left end of each first air inlet pipe 8 passes through the left side of the flue gas inlet channel 26 of the boiler 25 and is located on the left side of the boiler 25. A first connecting pipe is fixedly connected between the lower outer side of the first air inlet pipe 8 and the upper outer side of the corresponding front exhaust pipe 2.

[0026] Depending on the requirements, the first nozzle can be a known technology, such as the "lower cone" disclosed in the publication number CN213913158U, entitled "A Type of Ammonia Injection Grille for SCR Denitrification System", where the upper front side of the connecting plate 3 is fixedly installed with the lower side of the impeller shaft of the lower cone. Alternatively, it can be the "fan blade and rotating shaft" disclosed in the publication number CN212017401U, entitled "A Novel Anti-clogging Sprayer for Ammonia Injection Grille", where the upper front side of the connecting plate 3 is fixedly installed with the lower end of the rotating shaft. The connecting plate 3 is a plate-shaped structure with the front part inclined upward relative to the rear part. The connecting plate 3 is vertically set, which can reduce the resistance of flue gas and ammonia.

[0027] The flue gas inlet 26 of boiler 25 is vertically arranged. A flue gas inlet is formed on one side of the bottom of boiler 25, and a flue gas outlet is formed on the other side of the top of boiler 25. The flue gas generated by combustion in boiler 25 is discharged through the economizer located at the boiler furnace outlet, and then discharged after passing through the air preheater, absorption tower, and emission device. An SCR reactor is installed in the flue gas duct connecting the economizer and the air preheater. After the air preheater, an electrostatic precipitator (or bag filter), absorption tower, wet electrostatic precipitator, emission device, and related auxiliary equipment are connected in sequence to allow the flue gas to pass through sequentially. These auxiliary equipment include: a denitrification reducing agent storage and metering mixing and conveying system, a denitrification reducing agent injection system, a limestone slurry preparation device, a by-product gypsum dewatering device, a flue gas conveying device, a process water supply device, a sump and emergency slurry treatment device, etc. These auxiliary devices can all adopt the equipment used in existing boiler systems, and will not be described in detail here.

[0028] During use, by setting the connecting plate 3, the first nozzle is positioned above the first spray pipe 1, which avoids the first nozzle clogging the outlet hole 6 of the front outlet pipe 2. Even if the outlet hole 6 is clogged, the blockage can be easily cleared with tools, making cleaning more convenient. This avoids the difficulty of disassembling the first nozzle from the front outlet pipe 2 after clogging. The first nozzle ensures that the ammonia gas flowing from the outlet hole 6 is evenly injected into the flue gas inlet channel 26 of the boiler 25, allowing the ammonia gas to mix fully with the flue gas. The evenly mixed ammonia gas and flue gas can effectively reduce the ammonia slip rate at the SCR outlet. Through optimization and modification, the overall performance of SCR can be improved, the ammonia slip concentration can be reduced, the air preheater can be prevented from clogging, the reducing agent consumption can be reduced, the fan power consumption can be reduced, the service life of the denitrification SCR catalyst can be extended, the efficiency of the air preheater and electrostatic precipitator can be improved, and the safe, economical and stable operation level of the unit can be enhanced.

[0029] The above-mentioned ammonia injection device can be further optimized and / or improved according to actual needs: Example 2: As an optimization of the above examples, as shown in the appendix. Figure 2 , 3 As shown in Figures 6 to 8, the first nozzle includes a base and a guide plate 5. The base includes several partition plates 4 evenly distributed along the circumference. The lower side of one partition plate 4 is fixedly installed together with the upper front side of the connecting plate 3. Each partition plate 4 has a guide plate 5 fixedly installed on its upper side. All the guide plates 5 are spirally distributed. The upper front side of the front air outlet pipe 2, corresponding to the position of the front side of the connecting plate 3, is provided with an air outlet 6 that connects the inside and outside.

[0030] Depending on the requirements, the base can be formed by fixing (welding) four circumferentially distributed partition plates 4 together, i.e., the base is cross-shaped. The width of the guide plate 5 gradually increases from bottom to top, and then gradually decreases, with the width being the largest in the middle of the height direction. The width of the upper and lower sides of the guide plate 5 is smaller than the width in the middle, which facilitates the welding and fixing of multiple guide plates 5 to the partition plates 4 (the guide plate 5 and the partition plate 4 can also be integrally formed). That is, the distance between the side of the guide plate 5 away from the central axis of the base and the side of the guide plate 5 close to the central axis of the base gradually decreases from bottom to top, and then gradually increases. The air outlet 6 is oblong, which facilitates the cleaning of impurities in the pipe. During use, after passing through the air outlet 6, the ammonia gas is evenly injected into the flue gas inlet channel 26 of the boiler 25 under the action of the upper guide plate 5. The spiral distribution of all the guide plates 5 can fully mix the ammonia gas with the flue gas, which can effectively reduce the flue gas resistance. The evenly mixed ammonia gas and flue gas can effectively reduce the ammonia escape rate at the SCR outlet.

[0031] Example 3: As an optimization of the above examples, as shown in the appendix. Figure 2 , 3 As shown in Figures 4, 6, and 9, several fixing plates 9 are fixedly installed on the outer side of the first nozzle 1 at intervals on the left and right. The upper part of each fixing plate 9 is fixedly installed together with the first air inlet pipe 8. The leftmost fixing plate 9 and the rightmost fixing plate 9 are fixedly installed together with the inner side of the flue gas inlet channel 26 of the boiler 25.

[0032] According to requirements, each fixing plate 9 has two through-holes on the left side of its front part, spaced vertically. The outer sides of the first air inlet pipe 8 and the first nozzle 1 are welded and fixed to the inner sides of the corresponding front fixing holes. The fixing plates 9 can fix the first nozzle 1 and the first air inlet pipe 8 together, improving stability. The leftmost and rightmost fixing plates 9 are welded and fixed to the inner side of the flue gas inlet channel 26 of the boiler 25, which can increase the installation area between the first nozzle 1 and the inner side of the flue gas inlet channel 26 of the boiler 25. This makes it easier to fix the front exhaust pipe 2 and the first air inlet pipe 8 to the inner side of the flue gas inlet channel 26 of the boiler 25.

[0033] Example 4: As an optimization of the above examples, as shown in the appendix. Figure 3 , 4As shown in Figures 6 and 9, a second nozzle 10 is provided between each pair of adjacent first nozzles 1. The second nozzle 10 has the same structure as the first nozzle 1. A first fixing hole is provided on the left side of the rear part of the fixing plate 9 corresponding to the position behind each first nozzle 1. The outer side of the second nozzle 10 and the inner side of the corresponding first fixing hole are fixedly installed together. A third ammonia injection assembly 11 with the same structure as the first ammonia injection assembly is provided on the outer front part of each second nozzle 10. A fourth ammonia injection assembly 23 with the same structure as the second ammonia injection assembly 7 is provided on the outer rear part of each second nozzle 10. A second air inlet pipe 12 is provided inside the flue gas inlet channel 26 of the boiler 25 above the second nozzle 10. The second air inlet pipe 12 has the same structure as the first air inlet pipe 8. A second fixing hole is provided on the upper left side of the fixing plate 9 corresponding to each first fixing hole. The outer side of the second air inlet pipe 12 and the inner side of the corresponding second fixing hole are fixedly installed together. A second connecting pipe is fixedly connected between the lower outer side of the second air inlet pipe 12 and the upper outer side of the corresponding second nozzle 10. A regulating valve 24 is installed on the outer side of the first nozzle 1 and the second nozzle 10 at the left side of the flue gas inlet channel 26 of the boiler 25.

[0034] According to the requirements, the first air inlet pipe 8 and the second air inlet pipe 12 on each fixed plate 9 are fixedly connected to the ammonia injection branch pipe 27 which is closed at one end. The other end of the ammonia injection branch pipe 27 is fixedly connected to the ammonia injection main pipe 28. The inlet of the ammonia injection main pipe 28 is connected to the outlet of the ammonia injection system.

[0035] During use, by setting the regulating valve 24, the difference in ammonia volume between the first air inlet pipe 8 and the second air inlet pipe 12 can be reduced, thereby improving the full-load adaptability of the ammonia injection system, effectively reducing excessive ammonia injection, lowering the ammonia escape rate, and achieving precise ammonia injection control for SCR denitrification.

[0036] Example 5: As an optimization of the above examples, as shown in the appendix. Figure 2 , 3 As shown in Figures 4, 6, and 9, the first connecting pipe includes a first left vertical pipe 13, a second left vertical pipe 14, a third left vertical pipe 15, and a left horizontal pipe 16 with a tubular structure closed at both ends. A first partition 17 is sealed and fixedly installed on the inner side of the middle of the first nozzle 1. A second partition 18 is sealed and fixedly installed on the inner side of the middle of the second nozzle 10 corresponding to the position of the first partition 17. The first left vertical pipe 13 and the second left vertical pipe 14 are respectively fixedly connected to the outer side of the upper part of the first nozzle 1 and the second nozzle 10, respectively, corresponding to the position to the left of the first partition 17. The upper end of the first left vertical pipe 13 and the upper end of the second left vertical pipe 14 are both fixedly connected to the outer side of the lower part of the left horizontal pipe 16. The third left vertical pipe 15 is fixedly connected between the upper part of the left horizontal pipe 16 and the outer side of the lower part of the first air intake pipe 8.

[0037] The second connecting pipe includes a first right vertical pipe 19, a second right vertical pipe 20, a third right vertical pipe 21, and a right horizontal pipe 22 with tubular structure closed at both ends. The first right vertical pipe 1 and the second right vertical pipe 10, which are located to the right of the second partition 18, are respectively fixedly connected to the outer upper part of the first right vertical pipe 19 and the second right vertical pipe 20. The upper ends of the first right vertical pipe 19 and the second right vertical pipe 20 are both fixedly connected to the outer lower part of the right horizontal pipe 22. The third right vertical pipe 21 is fixedly connected between the upper part of the right horizontal pipe 22 and the outer lower part of the second air intake pipe 12.

[0038] A first baffle 17 is sealed and fixedly installed on the inner side of the middle of the first nozzle 1, that is, the length of the first nozzle 1 on both the left and right sides of the first baffle 17 is the same, and the first baffle 17 is located at half the length of the first nozzle 1. A second baffle 18 is sealed and fixedly installed on the inner side of the middle of the second nozzle 10 corresponding to the position of the first baffle 17, that is, the length of the second nozzle 10 on both the left and right sides of the second baffle 18 is the same, and the second baffle 18 is located at half the length of the second nozzle 10. During use, this configuration allows ammonia gas to be introduced into the left side of the first nozzle 1 and the left side of the second nozzle 10 on the inner left side of the flue gas inlet channel 26 of the boiler 25 via the first air inlet pipe 8. Similarly, the second air inlet pipe 12 allows ammonia gas to be introduced into the right side of the first nozzle 1 and the right side of the second nozzle 10 on the inner right side of the flue gas inlet channel 26 of the boiler 25. This results in a more balanced ammonia gas flow rate between the left and right sides of the first nozzle 1 and the second nozzle 10. The opening of the first air inlet pipe 8 and the second air inlet pipe 12 can be adjusted via the regulating valve 24, thereby further balancing the ammonia gas flow rate between the left and right sides of the first nozzle 1 and the second nozzle 10. This enables precise and appropriate ammonia injection in multiple zones, improving the full-load adaptability of the ammonia injection system. This avoids excessive or insufficient ammonia injection in certain areas, reduces ammonia escape rate, and achieves precise ammonia injection control for SCR denitrification.

[0039] The above technical features constitute various embodiments of this utility model, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. An ammonia injection device, applied to a boiler, characterized in that... The system includes a first nozzle, a first ammonia injection assembly, a second ammonia injection assembly, and a first air inlet pipe. Several first nozzles are spaced apart in the boiler's flue gas inlet passage. The left and right ends of each first nozzle are fixedly installed to the inner side of the boiler's flue gas inlet passage. Several first ammonia injection assemblies are spaced apart on the outer front part of each first nozzle. Each first ammonia injection assembly includes a front outlet pipe, a connecting plate, and a first nozzle head. Several front-end-closed front outlet pipes are fixedly connected to the outer front part of the first nozzle at intervals. A connecting plate is fixedly installed on the outer upper part of each first nozzle corresponding to a front outlet pipe, with the front of the connecting plate located in front of the front outlet pipe. Above, a first nozzle is provided on the upper front side of the connecting plate. An air outlet hole with internal and external communication is provided on the upper outer side of the front air outlet pipe corresponding to the position of the first nozzle. A second ammonia injection assembly is provided on the rear outer side of the first nozzle on the left side of each front air outlet pipe. The second ammonia injection assembly has the same structure as the first ammonia injection assembly. A first air inlet pipe with a closed right end is fixedly installed on the inner side of the boiler's flue gas passage above each first nozzle. The left end of each first air inlet pipe is sealed and passes through the left side of the boiler's flue gas passage and is located on the left side of the boiler. A first connecting pipe is fixedly connected between the lower outer side of the first air inlet pipe and the upper outer side of the corresponding front air outlet pipe.

2. The ammonia injection device according to claim 1, characterized in that... The first nozzle includes a base and a guide plate. The base includes several partition plates evenly distributed around the circumference. The lower side of one partition plate is fixedly installed together with the upper front side of the connecting plate. A guide plate is fixedly installed on the upper side of each partition plate. All the guide plates are spirally distributed. A front air outlet hole with internal and external communication is provided on the upper front side of the front air outlet pipe corresponding to the position of the front side of the connecting plate.

3. The ammonia injection device according to claim 1 or 2, characterized in that... Several fixing plates are fixedly installed at intervals on the outer side of the first nozzle. The upper part of each fixing plate is fixedly installed together with the first air inlet pipe. The leftmost fixing plate and the rightmost fixing plate are fixedly installed together with the inner side of the boiler's flue gas inlet channel.

4. The ammonia injection device according to claim 3, characterized in that... A second nozzle is provided between each pair of adjacent first nozzles. The second nozzle has the same structure as the first nozzle. A first fixing hole that runs through the left side of the rear part of the fixing plate corresponding to the position behind each first nozzle is provided. The outer side of the second nozzle and the inner side of the corresponding first fixing hole are fixedly installed together. A third ammonia injection assembly with the same structure as the first ammonia injection assembly is provided on the outer front part of each second nozzle. A fourth ammonia injection assembly with the same structure as the second ammonia injection assembly is provided on the outer rear part of each second nozzle. A second air inlet pipe is provided on the inner side of the boiler's flue gas passage above each second nozzle. The second air inlet pipe has the same structure as the first air inlet pipe. A second fixing hole that runs through the left side of the upper part of the fixing plate corresponding to the position of each first fixing hole is provided. The outer side of the second air inlet pipe and the inner side of the corresponding second fixing hole are fixedly installed together. A second connecting pipe is fixedly connected between the outer lower part of the second air inlet pipe and the outer upper part of the corresponding second nozzle. A regulating valve is installed on the outer side of both the first nozzle and the second nozzle at the position to the left of the boiler's flue gas passage.

5. The ammonia injection device according to claim 4, characterized in that... The first connecting pipe includes a first left vertical pipe, a second left vertical pipe, a third left vertical pipe, and a left horizontal pipe with a tubular structure closed at both ends. A first baffle is sealed and fixedly installed on the inner side of the middle of the first nozzle. A second baffle is sealed and fixedly installed on the inner side of the middle of the second nozzle corresponding to the position of the first baffle. The first left vertical pipe and the second left vertical pipe are respectively fixedly connected to the outer side of the upper part of the first nozzle and the second nozzle, respectively, at the position to the left of the first baffle. The upper end of the first left vertical pipe and the upper end of the second left vertical pipe are both fixedly connected to the outer side of the lower part of the left horizontal pipe. The third left vertical pipe is fixedly connected between the upper part of the left horizontal pipe and the outer side of the lower part of the first air intake pipe. The second connecting pipe includes a first right vertical pipe, a second right vertical pipe, a third right vertical pipe, and a right horizontal pipe with a tubular structure closed at both ends. The first right vertical pipe and the second right vertical pipe are fixedly connected to the upper outer sides of the first nozzle and the second nozzle, respectively, corresponding to the position to the right of the second partition. The upper ends of the first right vertical pipe and the second right vertical pipe are fixedly connected to the lower outer side of the right horizontal pipe. The third right vertical pipe is fixedly connected between the upper part of the right horizontal pipe and the lower outer side of the second air intake pipe.

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