Flue gas denitration device

Abstract

The utility model provides a kind of flue gas denitrification device, belong to flue gas denitrification equipment technical field, including the gas inlet pipe of one end with steam main pipe connection in boiler, further include liquid inlet pipe for conveying urea solution, for mixing steam and urea solution mixing mechanism, the other end of liquid inlet pipe and gas inlet pipe is respectively connected with mixing mechanism, mixing mechanism is connected with distribution joint, several distribution pipes are arrayed on distribution joint, several distribution pipes are all connected with injection pipe, the other end of injection pipe is connected with the spray head of injection towards flue interior.The flue gas denitrification device provided by the utility model, steam is transported to mixing mechanism by gas inlet pipe, the urea solution in liquid inlet pipe is mixed atomization and transported to distribution joint by Venturi mixer of mixing mechanism by steam, uniformly mixed under the action of helical blade of distribution joint, finally, spray into different parts in flue by multiple spray heads, urea is more uniform after steam atomization and sprayed into flue, and denitration reaction effect is better.

Description

Technical Field

[0001] This utility model relates to the technical field of flue gas denitrification equipment, specifically to a flue gas denitrification device. Background Technology

[0002] Nitrogen oxides (NOx) in flue gas from coal-fired boilers are one of the main sources of air pollution. Selective non-catalytic reduction (SNCR) denitrification technology is widely used due to its low cost and simple modification. Traditional SNCR systems typically use urea solution as a reducing agent, which is directly injected into the high-temperature zone of the flue gas duct through an injection device. For example, Chinese utility model patent CN214159132U discloses a flue gas denitrification device, including: a denitrification reactor; multiple denitrification agent injectors installed inside the denitrification reactor; each denitrification agent injector includes a support pipe; the support pipe is fixed to the inner wall of the denitrification reactor; a temperature sensor is installed on the support pipe; an electric valve for adjusting the denitrification agent flow rate is installed at the denitrification agent inlet of the support pipe; the electric valve adjusts according to the temperature measured by the temperature sensor to ensure that the amount of denitrification agent matches the temperature. This utility model's flue gas denitrification device has a simple structure, can adjust the denitrification agent flow rate according to temperature, has high denitrification efficiency, and reduces agent waste.

[0003] However, in the aforementioned existing technologies, when urea solution is directly injected into the flue, the mixing effect between the urea solution and the flue gas depends on the flue turbulence. When the flue gas in the flue is unstable, the uneven distribution of urea solution leads to insufficient denitrification reaction and low denitrification efficiency, making it difficult to meet the denitrification requirements of large power generation boilers. This solution addresses this technical problem. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides a flue gas denitrification device. Steam is transported to a mixing mechanism through an inlet pipe. The venturi mixer in the mixing mechanism atomizes and mixes the urea solution in the inlet pipe with steam, then transports it to a distribution connector. Under the action of the spiral blades of the distribution connector, the mixture is homogeneous and discharged through a distribution pipe. Finally, it is sprayed into different parts of the flue through multiple nozzles. Compared with directly spraying the urea solution into the flue, the urea solution is sprayed into the flue more evenly after being atomized by steam, resulting in a better denitrification reaction effect.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a flue gas denitrification device, including a steam inlet pipe connected at one end to a steam header in a boiler, a liquid inlet pipe for conveying urea solution, a mixing mechanism for mixing steam and urea solution, the other ends of the liquid inlet pipe and the steam inlet pipe being respectively connected to the mixing mechanism, the mixing mechanism being connected to a distribution joint, a plurality of distribution pipes being arranged in an array on the distribution joint, each of the plurality of distribution pipes being connected to an injection pipe, and the other end of the injection pipe being connected to a nozzle that sprays toward the inside of the flue.

[0006] The mixing mechanism is provided in several parts. The other end of the steam inlet pipe is connected to a steam distribution cylinder. The steam inlet pipe is connected to the steam inlet of the steam distribution cylinder. The exhaust port of the steam distribution cylinder is connected to several of the mixing mechanisms. The drain port of the steam distribution cylinder is provided with a condensate drain. All of the mixing mechanisms are connected to the liquid inlet pipe.

[0007] One end of the inlet pipe is connected to a delivery pump for pumping urea solution, and the other end of the inlet pipe is provided with a plurality of inlet branch pipes, the number of which is the same as that of the mixing mechanism, and the plurality of inlet branch pipes are respectively connected to the mixing mechanism.

[0008] The mixing mechanism is a Venturi mixer. The steam inlet pipe is connected to the nozzle of the Venturi mixer, the liquid inlet pipe is connected to the suction pipe of the Venturi mixer, and the outlet of the Venturi mixer is connected to the distribution connector. The distribution connector is equipped with spiral blades for mixing steam and urea solution.

[0009] The mixing mechanism is provided with a protective shell on its outer side, and the protective shell is fixedly installed on the side of the boiler.

[0010] The inlet pipe is sequentially equipped with a control valve assembly, a pressure transmitter, and a flow meter. The control valve assembly includes a solenoid valve and a bypass pipe with both ends connected to the solenoid valve. The bypass pipe is equipped with a bypass valve.

[0011] A backwash pipe for flushing the inlet pipe is provided between the control valve assembly and the delivery pump.

[0012] The steam inlet pipe is sequentially equipped with a second control valve assembly, a thermometer, a second pressure transmitter, and a second flow meter. The second control valve assembly includes a second solenoid valve and a second bypass pipe with both ends connected to the second solenoid valve. The second bypass pipe is equipped with a second bypass valve. A check valve is provided at the end of the steam inlet pipe near the steam header.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] (1) Steam is transported to the mixing mechanism through the steam inlet pipe. The Venturi mixer of the mixing mechanism mixes and atomizes the urea solution in the liquid inlet pipe through steam and transports it to the distribution joint. Under the action of the spiral blades of the distribution joint, the mixture is uniform and discharged through the distribution pipe. Finally, it is sprayed into different parts of the flue through multiple nozzles. Compared with directly spraying the urea solution into the flue, the urea solution is sprayed into the flue more uniformly after being atomized by steam, and the denitrification reaction effect is better.

[0015] (2) By setting up the steam distribution cylinder, the steam is distributed to multiple mixing mechanisms. The urea solution is also distributed to multiple mixing mechanisms through multiple inlet branch pipes branched from the inlet pipe. After being atomized by the Chinese Qiuli mixer in each mixing mechanism, it is distributed to the corresponding nozzles through several distribution pipes of the distribution joint and distributed to different positions in the flue, thereby improving the denitrification reaction effect.

[0016] (3) The condensate is discharged through the steam trap at the bottom of the steam separator, making the steam entering the mixing mechanism cleaner. The backwash pipe on the inlet pipe is used to backwash the inlet pipe and the mixing mechanism, resulting in better quality of urea solution delivered by the inlet pipe. This improves the mixing quality of steam and urea solution in the mixing mechanism and further enhances the denitrification reaction effect.

[0017] (4) By using a flow meter and an online monitoring system for nitrogen oxides in flue gas, the control valve group 1 and control valve group 2 are PID regulated, so that the urea solution and steam quantities are more accurately matched with the nitrogen oxides in the flue gas, thereby improving the denitrification reaction effect. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the flue gas denitrification process of this utility model;

[0019] Figure 2 This is a schematic diagram of the structure of the hybrid mechanism of this utility model;

[0020] Figure 3 This is a cross-sectional structural schematic diagram of the hybrid mechanism of this utility model;

[0021] Figure 4 This is a schematic diagram of the distribution connector of this utility model.

[0022] In the diagram: 1. Steam inlet pipe; 2. Liquid inlet pipe; 21. Liquid inlet branch pipe; 3. Mixing mechanism; 31. Protective housing; 4. Distribution connector; 41. Distribution pipe; 42. Spiral blade; 5. Injection pipe; 51. Nozzle; 6. Steam cylinder; 7. Drainage device; 8. Transfer pump; 9. Control valve assembly one; 91. Solenoid valve one; 92. Bypass pipe one; 93. Bypass valve one; 10. Pressure transmitter one; 11. Flow meter one; 12. Backwash pipe; 13. Control valve assembly two; 131. Solenoid valve two; 132. Bypass pipe two; 133. Bypass valve two; 14. Thermometer; 15. Pressure transmitter two; 16. Flow meter two; 17. Check valve. Detailed Implementation

[0023] To more clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0024] See Figures 1-4 A flue gas denitrification device includes a steam inlet pipe 1 connected at one end to a steam header in a boiler, a liquid inlet pipe 2 for conveying urea solution, a mixing mechanism 3 for mixing steam and urea solution, and the other ends of the liquid inlet pipe 2 and the steam inlet pipe 1 are respectively connected to the mixing mechanism 3. The mixing mechanism 3 is connected to a distribution connector 4, and a plurality of distribution pipes 41 are arranged in an array on the distribution connector 4. Each of the plurality of distribution pipes 41 is connected to an injection pipe 5, and the other end of the injection pipe 5 is connected to a nozzle 51 that sprays toward the inside of the flue.

[0025] Several mixing mechanisms 3 are provided. The other end of the steam inlet pipe 1 is connected to the steam distribution cylinder 6. The steam inlet pipe 1 is connected to the steam inlet of the steam distribution cylinder 6. The exhaust port of the steam distribution cylinder 6 is connected to several mixing mechanisms 3 respectively. The drain port of the steam distribution cylinder 6 is equipped with a condensate trap 7. Several mixing mechanisms 3 are all connected to the liquid inlet pipe 2.

[0026] One end of the inlet pipe 2 is connected to a delivery pump 8 for pumping urea solution, and the other end of the inlet pipe 2 is provided with several inlet branch pipes 21. The number of inlet branch pipes 21 is the same as that of the mixing mechanism 3, and the several inlet branch pipes 21 are respectively connected to the mixing mechanism 3.

[0027] The mixing mechanism 3 is a Venturi mixer. The steam inlet pipe 1 is connected to the nozzle of the Venturi mixer, the liquid inlet pipe 2 is connected to the suction pipe of the Venturi mixer, and the outlet of the Venturi mixer is connected to the distribution connector 4. The distribution connector 4 is equipped with a spiral blade 42 for mixing steam and urea solution.

[0028] A protective housing 31 is provided on the outside of the mixing mechanism 3. The protective housing 31 is fixedly installed on the side of the boiler. The protective housing 31 protects the Venturi mixer inside the mixing mechanism 3 and fixes the mixing mechanism 3 to the side of the boiler through the bracket on the protective housing 31, ensuring the stable and reliable operation of the mixing mechanism 3. The inlet of the Venturi mixer, the outlet and the nozzle joint are all located on the outside of the protective housing 31, so as to facilitate the connection and maintenance of the mixing mechanism 3 with the external pipeline.

[0029] The inlet pipe 2 is sequentially equipped with a control valve group 9, a pressure transmitter 10 and a flow meter 11. The control valve group 9 includes a solenoid valve 91 and a bypass pipe 92 with both ends connected to the solenoid valve 91. A bypass valve 93 is installed on the bypass pipe 92.

[0030] A backwash pipe 12 for flushing the inlet pipe 2 is provided between the control valve group 9 and the delivery pump 8. A valve is provided on the backwash pipe 12. The backwash pipe 12 can not only flush the inlet pipe 2, but also flush the mixing mechanism 3 and the nozzle 51 to avoid blockage of the pipeline.

[0031] The steam inlet pipe 1 is sequentially equipped with a control valve assembly 2 13, a thermometer 14, a pressure transmitter 2 15, and a flow meter 2 16. The control valve assembly 2 13 includes a solenoid valve 2 131 and a bypass pipe 2 132 connected to the solenoid valve 2 131 at both ends. A bypass valve 2 133 is installed on the bypass pipe 2 132. A check valve 17 is installed at the end of the steam inlet pipe 1 near the steam header.

[0032] Among them, control valve group 19, pressure transmitter 10, flow meter 11, control valve group 2 13, thermometer 14, pressure transmitter 2 15, and flow meter 2 16 are all electrically connected to the flow meter and flue gas nitrogen oxide online monitoring system in the flue through the controller. The control valve group 19 and control valve group 2 13 are PID regulated by the flow meter and flue gas nitrogen oxide online monitoring system to match the urea solution and steam volume with the flue gas, thereby achieving a better denitrification effect. The controller's PID regulation of solenoid valve 191 and solenoid valve 2 131 is implemented using existing technology and will not be described in detail here.

[0033] The specific working process of this utility model:

[0034] In operation, steam from the main steam pipe enters the steam distribution cylinder 6 through the steam inlet pipe 1. Under the distribution of the steam distribution cylinder 6, steam enters the nozzles of several venturi mixers in the mixing mechanism 3. At the same time, urea solution, pumped by the delivery pump 8, is distributed to several inlet branch pipes 21 through the liquid inlet pipe 2. Then, the liquid inlet branch pipes 21 enter the suction pipes of the venturi mixers. The negative pressure generated when the steam enters the nozzles draws in the urea solution in the suction pipes and mixes and atomizes it in the venturi mixer. After being discharged through the throat of the venturi mixer, it enters the distribution connector 4. Under the further mixing action of the spiral blades 42 in the distribution connector 4, the atomized urea solution is dispersed more evenly. Finally, it is distributed to different distribution pipes 41 and transported to the corresponding nozzles 51 through the hoses connected to the distribution pipes 41. Finally, it is sprayed into different parts of the flue through the nozzles 51. In the flue, the evenly atomized urea solution reacts with nitrogen oxides to achieve the purpose of denitrification.

[0035] Steam is delivered to the mixing mechanism 3 through the steam inlet pipe 1. The venturi mixer of the mixing mechanism 3 mixes and atomizes the urea solution in the liquid inlet pipe 2 with steam and delivers it to the distribution joint 4. Under the action of the spiral blades 42 of the distribution joint 4, the mixture is uniform and discharged through the distribution pipe 41. Finally, it is sprayed into different parts of the flue through multiple nozzles 51. Compared with directly spraying the urea solution into the flue, the urea solution is sprayed into the flue more uniformly after being atomized by steam, and the denitrification reaction effect is better.

[0036] By setting up the steam distribution cylinder 6, the steam is distributed to multiple mixing mechanisms 3. The urea solution is also distributed to multiple mixing mechanisms 3 through multiple inlet branch pipes 21 branched from the liquid inlet pipe 2. After being atomized by the Venturi mixer in each mixing mechanism 3, it is then distributed to the corresponding nozzles 51 through several distribution pipes 41 of the distribution connector 4, and then distributed to different positions in the flue. The number and position of the nozzles 51 in the flue are increased, which improves the number and flexibility of the nozzle arrangement and thus improves the denitrification reaction effect.

[0037] The condensate is discharged through the steam trap 7 at the bottom of the steam separator 6, making the steam entering the mixing mechanism 3 cleaner. The backwash pipe 12 on the inlet pipe 2 backwashes the inlet pipe 2 and the mixing mechanism 3, avoiding pipe blockage. The urea solution delivered by the inlet pipe 2 is of better quality, which improves the mixing quality of steam and urea solution in the mixing mechanism 3 and further improves the denitrification reaction effect.

[0038] By installing a thermometer 14, a pressure transmitter 15, and a flow meter 16 on the steam inlet pipe 1, and a pressure transmitter 10 and a flow meter 11 on the liquid inlet pipe 2, and by installing a control valve group 9, a pressure transmitter 10, a flow meter 11, a control valve group 2 13, a thermometer 14, a pressure transmitter 15, and a flow meter 16, all of which are electrically connected to the flow meter and the flue gas nitrogen oxide online monitoring system in the flue through a controller, the control valve group 9 and the control valve group 2 13 are PID regulated by the flow meter and the flue gas nitrogen oxide online monitoring system, so that the urea solution and steam volume are more accurately matched with the nitrogen oxides in the flue gas, thereby improving the denitrification reaction effect.

[0039] PID (Proportional-Integral-Derivative) control is a widely used engineering control technique that adjusts system errors through proportional, integral, and derivative control methods to achieve precise control. Its controller parameters can be determined through theoretical calculations or engineering experience. It features simple structure, good stability, and convenient adjustment, and is widely used in industrial automation. The PID adjustment in this solution utilizes existing technology and will not be detailed further.

[0040] The technical features of this utility model not described can be implemented by or by using existing technology, and will not be repeated here. Of course, the above description is not a limitation of this utility model, and this utility model is not limited to the examples above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this utility model should also be within the protection scope of this utility model.

Claims

1. A flue gas denitration device comprising a steam inlet pipe (1) connected to a steam main pipe in a boiler at one end, characterized in that, It also includes an inlet pipe (2) for conveying urea solution, a mixing mechanism (3) for mixing steam and urea solution, the other ends of the inlet pipe (2) and the steam inlet pipe (1) are respectively connected to the mixing mechanism (3), the mixing mechanism (3) is connected to a distribution connector (4), a plurality of distribution pipes (41) are arranged in an array on the distribution connector (4), and a plurality of the distribution pipes (41) are connected to an injection pipe (5), the other end of the injection pipe (5) is connected to a nozzle (51) that sprays toward the inside of the flue.

2. The flue gas denitrification device according to claim 1, characterized in that, The mixing mechanism (3) is provided in several ways. The other end of the steam inlet pipe (1) is connected to the steam distribution cylinder (6). The steam inlet pipe (1) is connected to the steam inlet of the steam distribution cylinder (6). The steam outlet of the steam distribution cylinder (6) is connected to several of the mixing mechanisms (3). The drain outlet of the steam distribution cylinder (6) is provided with a drain condensate (7). Several of the mixing mechanisms (3) are connected to the liquid inlet pipe (2).

3. The flue gas denitrification device according to claim 2, characterized in that, One end of the inlet pipe (2) is connected to a delivery pump (8) for pumping urea solution, and the other end of the inlet pipe (2) is provided with a plurality of inlet branch pipes (21). The number of inlet branch pipes (21) is the same as that of the mixing mechanism (3), and the plurality of inlet branch pipes (21) are respectively connected to the mixing mechanism (3).

4. The flue gas denitrification device according to claim 3, characterized in that, The mixing mechanism (3) is a Venturi mixer. The steam inlet pipe (1) is connected to the nozzle of the Venturi mixer. The liquid inlet pipe (2) is connected to the suction pipe of the Venturi mixer. The outlet of the Venturi mixer is connected to the distribution connector (4). The distribution connector (4) is provided with a spiral blade (42) for mixing steam and urea solution.

5. The flue gas denitrification device according to claim 4, characterized in that, The mixing mechanism (3) is provided with a protective shell (31) on its outer side, and the protective shell (31) is fixedly installed on the side of the boiler.

6. The flue gas denitrification device according to claim 3, characterized in that, The inlet pipe (2) is sequentially provided with a control valve group (9), a pressure transmitter (10) and a flow meter (11). The control valve group (9) includes a solenoid valve (91) and a bypass pipe (92) with both ends connected to the solenoid valve (91). A bypass valve (93) is provided on the bypass pipe (92).

7. The flue gas denitrification device according to claim 6, characterized in that, A backwash pipe (12) for flushing the inlet pipe (2) is provided between the control valve group (9) and the delivery pump (8).

8. The flue gas denitrification device according to claim 3, characterized in that, The steam inlet pipe (1) is sequentially provided with a control valve group two (13), a thermometer (14), a pressure transmitter two (15) and a flow meter two (16). The control valve group two (13) includes a solenoid valve two (131) and a bypass pipe two (132) with both ends connected to the solenoid valve two (131). A bypass valve two (133) is provided on the bypass pipe two (132). A check valve (17) is provided at one end of the steam inlet pipe (1) near the steam header.

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