A denitration system and incineration system

Abstract

This invention belongs to the technical field of hazardous waste treatment equipment, and discloses a denitrification system and an incineration system. The denitrification system includes a secondary combustion chamber, a preparation unit, and an injection unit. The secondary combustion chamber is used to combust the flue gas and maintain its temperature within a preset temperature range. The preparation unit is used to prepare a urea solution. The injection unit includes a spray gun located at the top of the secondary combustion chamber, which is connected to the preparation unit via a delivery pipeline to atomize the urea solution output from the preparation unit and spray it into the secondary combustion chamber. In this invention, the atomized urea droplets are sprayed downwards from the top, forming convective or cross-flow contact with the rising or horizontally flowing flue gas, extending the mixing path between the droplets and the flue gas, increasing the contact opportunity, and reducing local reagent loss caused by complex flow fields.

Description

Technical Field

[0001] This utility model relates to the technical field of hazardous waste treatment equipment, and in particular to a denitrification system and an incineration system. Background Technology

[0002] Controlling nitrogen oxides in the exhaust gas of incineration systems is a core aspect of environmental governance. During incineration, fuel-related nitrogen oxides are inevitably generated from the combustion of nitrogen-containing waste. Currently, emissions are mainly achieved through front-end measures such as reasonable blending to reduce the nitrogen content of waste entering the furnace and controlling combustion temperature, combined with back-end non-selective catalytic reduction (SNCR) denitrification systems.

[0003] However, existing SNCR systems are mainly used to atomize urea solution into fine particles to promote mixing with flue gas. However, existing SNCR systems generally suffer from insufficient uniformity in the mixing of the atomized urea solution with the flue gas, resulting in incomplete agent coverage at the top flue gas cross-section of the secondary combustion chamber, especially when the flue gas flow is complex, leading to localized incomplete reactions.

[0004] Therefore, the above problems urgently need to be solved. Utility Model Content

[0005] The purpose of this invention is to provide a denitrification system and an incineration system to reduce local reagent loss caused by complex flow fields.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A denitrification system includes a secondary combustion chamber, a preparation unit, and an injection unit, wherein:

[0008] The secondary combustion chamber is used to burn the flue gas and maintain the temperature of the flue gas within a preset temperature range;

[0009] The preparation unit is used to prepare urea solution;

[0010] The injection unit includes a spray gun disposed at the top of the secondary combustion chamber. The spray gun is connected to the preparation unit through a delivery pipeline to atomize the urea solution output by the preparation unit and spray it into the secondary combustion chamber.

[0011] Preferably, the preparation unit includes:

[0012] Urea preparation tank, used to hold urea granules and water, so that the urea granules dissolve in the water;

[0013] A stirrer is disposed inside the urea preparation tank, and the stirrer is configured to stir urea particles and water to prepare a urea solution;

[0014] A heater is disposed inside the urea preparation tank, and the heater is configured to heat the inner cavity of the urea preparation tank.

[0015] Preferably, the preparation unit further includes:

[0016] A urea storage tank, one end of which is connected to the urea preparation tank and the other end of which is connected to the spray gun, is used to store the urea solution in the urea preparation tank;

[0017] Two urea transfer pumps are connected in parallel between the urea preparation tank and the urea storage tank. The urea transfer pumps are configured to transport the urea solution in the urea preparation tank to the urea storage tank.

[0018] Preferably, the preparation unit further includes:

[0019] A dilution water supply unit is connected to the urea preparation tank, and the dilution water supply unit is used to supply water to the urea preparation tank;

[0020] An adjusting element is used to adjust the amount of water supplied by the dilution water supply element.

[0021] Preferably, the secondary combustion chamber includes a cylinder, a flue gas outlet, a flue gas inlet, and a combustion furnace, wherein:

[0022] The cylinder has a processing chamber inside, and the spray gun is located at the top of the processing chamber;

[0023] The flue gas outlet is located at the upper part of the cylinder, and the flue gas inlet is located at the lower part of the cylinder. The flue gas output from the first combustion chamber is supplied into the treatment chamber through the flue gas inlet, and the flue gas processed by the second combustion chamber is discharged from the treatment chamber through the flue gas outlet.

[0024] The combustion furnace is disposed on the cylinder and is configured to mix and ignite air with the flue gas supplied by the flue gas inlet.

[0025] Preferably, the combustion furnace and the spray gun are connected to the same air supply pipeline, and the spray gun atomizes the urea solution by compressing the air supplied by the air supply pipeline.

[0026] Preferably, the combustion furnace is located at the lower part of the cylinder.

[0027] Preferably, the injection unit includes a plurality of spray guns distributed at the top of the secondary combustion chamber.

[0028] Preferably, the spray gun is a dual-fluid nozzle.

[0029] An incineration system includes a primary combustion chamber, a delivery pipeline, a secondary combustion chamber, and the aforementioned denitrification system, wherein:

[0030] The first combustion chamber is used to incinerate waste, and the flue gas output from the first combustion chamber is input into the second combustion chamber through the conveying pipeline so that the second combustion chamber can continue to burn unburned combustible gas;

[0031] The denitrification system is used to spray atomized urea solution into the secondary combustion chamber so that the atomized urea solution mixes with the flue gas in the secondary combustion chamber.

[0032] The beneficial effects of this utility model are:

[0033] This invention places the spray gun at the top of the secondary combustion chamber, a critical path for flue gas flow with a relatively uniform temperature field. Atomized urea droplets are sprayed downwards from the top, creating convective or cross-flow contact with the rising or horizontally flowing flue gas, extending the mixing path and increasing contact opportunities. Furthermore, the preset temperature range at the top of the secondary combustion chamber not only provides the optimal reaction temperature but also suitable conditions for droplet evaporation and diffusion. The high-temperature environment accelerates droplet evaporation, allowing urea to be converted into active ingredients (such as amino groups) more quickly. Simultaneously, the turbulent flow of flue gas within the secondary combustion chamber further promotes uniform mixing of the gas and liquid phases, reducing localized agent loss due to complex flow fields.

[0034] In addition, the preparation unit and the spraying unit are directly connected via pipelines to ensure a stable supply of urea solution. The spray gun is located at the top of the secondary combustion chamber, which shortens the distance between the agent spray point and the high-temperature reaction zone, reduces the ineffective loss of droplets in the low-temperature region, and allows the agent to accurately act on the main areas where nitrogen oxides are present. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the denitrification system provided by this utility model;

[0036] Figure 2 This is a schematic diagram of the preparation unit provided by this utility model;

[0037] Figure 3 This is a schematic diagram of the structure of the urea preparation tank provided by this utility model;

[0038] Figure 4 This is a schematic diagram of the structure of the secondary combustion chamber provided by this utility model.

[0039] In the picture:

[0040] 1. Secondary combustion chamber; 11. Shell; 12. Flue gas outlet; 13. Flue gas inlet; 14. Combustion furnace;

[0041] 2. Preparation unit; 21. Urea preparation tank; 22. Stirrer; 23. Heater; 24. Urea storage tank; 25. Urea transfer pump; 26. Dilution water supply unit; 27. Adjustment unit;

[0042] 3. Spraying unit; 31. Spray gun;

[0043] 4. Air supply pipeline. Detailed Implementation

[0044] Before explaining any implementation of this application in detail, it should be understood that this application is not limited to its application to the structural details and component arrangements set forth in the following description or shown in the above drawings.

[0045] In this application, the terms "comprising," "including," "having," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0046] In this application, the term "and / or" describes a relationship between related objects, indicating that three relationships can exist. For example, a centrifugal vortex magnetic pump and / or a centrifugal vortex magnetic pump can represent: the existence of only one centrifugal vortex magnetic pump, the simultaneous existence of one centrifugal vortex magnetic pump and a centrifugal vortex magnetic pump, or the existence of only one centrifugal vortex magnetic pump. Additionally, the character " / " in this application generally indicates that the preceding and following related objects have an "and / or" relationship.

[0047] In this application, the terms "connection," "combination," "coupling," and "installation" can refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, a direct connection refers to two parts or components being connected together without the need for an intermediary, while an indirect connection refers to two parts or components each being connected to at least one intermediary, with the connection achieved through the intermediary. Furthermore, "connection" and "coupling" are not limited to physical or mechanical connections or couplings, but can also include electrical connections or couplings.

[0048] In this application, those skilled in the art will understand that relative terms (e.g., “about,” “approximately,” “basically,” etc.) used in conjunction with quantities or conditions are to include the values ​​and have the meaning indicated by the context. For example, such relative terms include at least the degree of error associated with the measurement of a particular value, tolerances associated with the particular value due to manufacturing, assembly, use, etc. Such terms should also be considered as disclosing a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values ​​not using relative terms should also be disclosed as specific values ​​with tolerances. Furthermore, “basically” when expressing relative angular relationships (e.g., substantially parallel, substantially perpendicular) may refer to a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) added to or subtracted from the indicated angle.

[0049] In this application, those skilled in the art will understand that the function performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0050] In this application, the directional terms "upper," "lower," "left," "right," "front," and "rear" are used to describe the orientation and positional relationships shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when an element is mentioned as being connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected through an intermediate element. It should also be understood that directional terms such as upper side, lower side, left side, right side, front side, and rear side not only represent positive orientation but can also be understood as lateral orientation. For example, "below" can include directly below, lower left, lower right, lower front, and lower rear.

[0051] Please see Figures 1 to 4 This embodiment provides a denitrification system, which includes a secondary combustion chamber 1, a preparation unit 2, and an injection unit 3. The secondary combustion chamber 1 is used to combust flue gas and maintain the temperature of the flue gas within a preset temperature range. The preparation unit 2 is used to prepare a urea solution. The injection unit 3 includes a spray gun 31 disposed on the top of the secondary combustion chamber 1. The spray gun 31 is connected to the preparation unit 2 through a delivery pipeline to atomize the urea solution output from the preparation unit 2 and spray it into the secondary combustion chamber 1.

[0052] It should be noted that the secondary combustion chamber 1, as a key unit of the incineration system, maintains the flue gas temperature stably within a preset temperature range through combustion regulation. The preset temperature range is 850-1000℃ (i.e., the optimal temperature window for SNCR reaction). This avoids the large-scale generation of thermal nitrogen oxides (the temperature of the secondary combustion chamber 1 is usually ≤1200℃, and the amount of thermal nitrogen oxides generated is extremely small), and also creates conditions for the back-end treatment of fuel nitrogen oxides. That is, the denitrification reaction of urea solution needs to be carried out efficiently within this preset temperature range.

[0053] With this configuration, the spray gun 31 of the injection unit 3 is located at the top of the secondary combustion chamber 1, directly facing the high-temperature flue gas area of ​​850-1000℃. The spray gun 31 then breaks the urea solution into tiny droplets, allowing them to fully contact the flue gas. This causes the atomized droplets to evaporate rapidly at high temperature and undergo a reduction reaction with nitric oxide, generating nitrogen, carbon dioxide, and water, thereby removing nitrogen oxides from the flue gas.

[0054] Understandably, the spray gun 31 is positioned at the top of the secondary combustion chamber 1, a critical path for flue gas flow with a relatively uniform temperature field. Atomized urea droplets are sprayed downwards from the top, creating convective or cross-flow contact with the rising or horizontally flowing flue gas, extending the mixing path and increasing contact opportunities. Furthermore, the preset temperature range at the top of the secondary combustion chamber 1 not only provides the optimal temperature for the reaction but also suitable conditions for droplet evaporation and diffusion. The high-temperature environment accelerates droplet evaporation, allowing urea to be converted into active ingredients (such as amino groups) more quickly. Simultaneously, the turbulent flow of flue gas within the secondary combustion chamber 1 further promotes uniform mixing of the gas and liquid phases, reducing localized agent loss due to complex flow fields.

[0055] It is also understandable that the preparation unit 2 and the spraying unit 3 are directly connected by pipelines to ensure a stable supply of urea solution. The spray gun 31 is located at the top of the secondary combustion chamber 1, which shortens the distance between the agent spraying point and the high-temperature reaction zone, reduces the ineffective loss of droplets in the low-temperature region, and enables the agent to act precisely on the main areas where nitrogen oxides are present.

[0056] Specifically, preparation unit 2 includes a urea preparation tank 21, a stirrer 22, and a heater 23. The urea preparation tank 21 contains urea granules and water to dissolve the urea granules in the water. The stirrer 22 is disposed within the urea preparation tank 21 and is configured to stir the urea granules and water to prepare a urea solution. The heater 23 is disposed within the urea preparation tank 21 and is configured to heat the interior of the urea preparation tank 21.

[0057] During the preparation process, the urea preparation tank 21 heats the water to a suitable dissolution temperature (60-70℃) under the action of the heater 23, and the stirrer 22 accelerates the dissolution of urea particles through mechanical mixing to form a uniform urea solution. Thus, through the synergy of the heater 23 and the stirrer 22, the temperature of the urea solution is controlled within a range conducive to dissolution and the mixing is enhanced, avoiding local concentration differences, ensuring uniform droplet size distribution after atomization, and increasing the contact area with the flue gas.

[0058] It should be noted that the stirrer 22 can adopt a paddle structure and achieve mixing by rotating the shaft driven by a motor. The heater 23 can adopt a coil-type electric heating structure or an immersion electric heating rod and adjust the power through a temperature control system. The specific models of the stirrer 22 and heater 23 can be selected according to the actual application scenario. This embodiment does not make specific requirements or limitations in this regard.

[0059] To improve the stability of the denitrification system, preparation unit 2 also includes a urea storage tank 24 and two urea transfer pumps 25. One end of the urea storage tank 24 is connected to the urea preparation tank 21, and the other end is connected to the spray gun 31. The urea storage tank 24 is used to store the urea solution in the urea preparation tank 21. The two urea transfer pumps 25 are connected in parallel between the urea preparation tank 21 and the urea storage tank 24. The urea transfer pumps 25 are configured to transport the urea solution from the urea preparation tank 21 to the urea storage tank 24.

[0060] Understandably, storing the prepared urea solution in the urea storage tank 24 can buffer the flow difference between the preparation and use stages, ensuring continuous liquid supply to the system. Even if the urea preparation tank 21 is in a shutdown state of dissolving urea (such as manual feeding or equipment maintenance), the liquid supply can still be maintained through the urea storage tank 24, avoiding interruption of denitrification due to the intermittency of the preparation process.

[0061] It is also understandable that the two transfer pumps connected in parallel form a "one-in-use, one-out-of-service" mode. When the main pump stops working due to failure, blockage, or maintenance, the standby pump can immediately start to take over the transportation task, ensuring uninterrupted solution transfer from the preparation tank to the storage tank. This eliminates the risk of single-point failure in a single-pump system. Even if a single pump experiences mechanical wear or seal leakage, normal material supply can still be maintained by switching pump sets, thereby achieving full-process continuity from solution preparation to storage and subsequent spraying, avoiding fluctuations in denitrification efficiency or the risk of exceeding environmental standards due to interruption of material supply. It should be noted that, in order to more accurately control the spray volume of urea solution, the urea transfer pump 25 preferably uses a pump with variable frequency control function, and stainless steel is the preferred pump body material.

[0062] Preparation unit 2 also includes a dilution water supply component 26 and a regulating component 27. One end of the dilution water supply component 26 is connected to the urea preparation tank 21, and the other end is connected to the spray gun 31. The dilution water supply component 26 is used to supply water to the urea preparation tank 21. The regulating component 27 is used to regulate the amount of water supplied by the dilution water supply component 26. By controlling the amount of dilution water in real time through the regulating component 27, the concentration of the urea solution can be precisely adjusted to the optimal range for SNCR reaction (such as 20% mass concentration), avoiding crystallization in the pipeline due to excessively high concentration or reduced reaction efficiency due to excessively low concentration.

[0063] In this embodiment, the dilution water supply component 26 uses a demineralized water pipeline with a filter. One end is connected to the demineralized water tank (or softened water system), and the other end is connected to the top of the urea preparation tank 21. A one-way valve on the pipeline prevents backflow of the solution, and the filter removes impurities to prevent clogging of the nozzles. The regulating component 27 can be a combination of an electromagnetic flow meter and an electric regulating valve. The electromagnetic flow meter monitors the water flow data in real time and transmits it to the PLC controller. The controller outputs a signal to the electric regulating valve (such as a pneumatic diaphragm valve or an electric ball valve) according to a preset concentration algorithm to dynamically adjust the opening degree to accurately control the dilution water volume; or a variable frequency water pump can be used to directly regulate the water supply flow rate, and the frequency converter receives the concentration sensor signal to achieve closed-loop control.

[0064] To further improve the mixing uniformity of atomized droplets and flue gas, the secondary combustion chamber 1 includes a cylinder 11, a flue gas outlet 12, a flue gas inlet 13, and a combustion furnace 14. A processing chamber is formed inside the cylinder 11, with the spray gun 31 located at the top of the processing chamber. The flue gas outlet 12 is located at the upper part of the cylinder 11, and the flue gas inlet 13 is located at the lower part of the cylinder 11. The flue gas output from the primary combustion chamber is supplied into the processing chamber through the flue gas inlet 13, and the flue gas processed by the secondary combustion chamber 1 is discharged from the processing chamber through the flue gas outlet 12. The combustion furnace 14 is mounted on the cylinder 11 and is configured to mix and ignite the air supplied by the flue gas inlet 13.

[0065] This configuration, achieved by igniting the air-flue gas mixture in the combustion furnace 14, continuously replenishes heat to the treatment chamber, ensuring the flue gas temperature remains stable within the 850-1000℃ range required for the SNCR reaction. Furthermore, the combustion process simultaneously enhances flue gas turbulence, resulting in a more uniform temperature distribution and preventing a decrease in reaction efficiency caused by localized low-temperature areas. More importantly, the flue gas enters from the flue gas inlet 13 at the bottom of the cylinder 11 and exits from the flue gas outlet 12 at the top, creating a counter-current or cross-flow contact with the spray direction of the top spray gun 31, extending the mixing path and residence time of the urea droplets with the flue gas. The vertical space design of the treatment chamber in the cylinder 11 provides ample mixing distance, allowing the atomized droplets to fully diffuse with the flue gas flow, covering the entire cross-section and reducing blind spots in reagent coverage caused by complex flow fields. In addition, the combustion process in the combustion furnace 14 not only maintains the temperature but also ensures the required oxygen content for the denitrification reaction by supplementing oxygen.

[0066] Specifically, the combustion furnace 14 and the spray gun 31 are connected to the same air supply line 4. The spray gun 31 atomizes the urea solution with air supplied by the compressed air supply line 4. Sharing the same air supply line 4 reduces the configuration of independent air source equipment (such as air compressors), reduces the complexity of pipeline layout and installation costs, and simplifies the control system architecture, facilitating centralized monitoring and maintenance. In addition, the combustion air of the combustion furnace 14 and the atomizing compressed air of the spray gun 31 share a stable air source, avoiding pressure fluctuation problems that may exist in multi-air source systems. For example, when the combustion load changes, the air supply system can adjust the air volume synchronously through frequency conversion regulation to ensure stable combustion in the combustion furnace 14 while maintaining a constant atomizing air pressure in the spray gun 31, avoiding uneven atomization particle size caused by air pressure fluctuations, thereby improving the mixing efficiency of urea droplets and flue gas.

[0067] Preferably, the combustion furnace 14 is located at the lower part of the cylinder 11. Located at the lower part of the cylinder 11, adjacent to the flue gas inlet 13, the combustion furnace 14 can preheat the low-temperature flue gas just entering the processing chamber, allowing the flue gas to quickly reach the 850-1000℃ temperature range required for the SNCR reaction during its ascent, avoiding the problem of delayed reaction in the initial low-temperature zone caused by heating in the middle of the cylinder 11. Simultaneously, the high-temperature gas flow generated by combustion mixes counter-currently with the flue gas, forming a gradient temperature field, extending the coverage length of the high-temperature zone, and ensuring the residence time of urea droplets within the effective temperature range.

[0068] In addition, the combustion flame of the lower combustion furnace 14 creates a strong bottom swirling effect, which collides with the upward flue gas flow to generate high-intensity turbulence, so that the urea droplets sprayed by the top spray gun 31 are fully mixed with the flue gas during the downward movement.

[0069] To extend the average residence time of urea droplets in the high-temperature zone, the injection unit 3 includes multiple spray guns 31 distributed at the top of the secondary combustion chamber 1. These multiple spray guns 31 form a comprehensive spray layout at the top of the secondary combustion chamber 1, achieving complete coverage of the treatment chamber's cross-section without dead angles and avoiding the problem of insufficient reagent in the sidewall areas caused by a single spray gun 31 spraying from the center. Furthermore, the simultaneous spraying of multiple spray guns 31 creates a composite atomization field, and the interaction of droplet groups from adjacent spray guns 31 generates micro-turbulence, creating a counter-impact with the upward-flowing flue gas, thus extending the average residence time of urea droplets in the high-temperature zone.

[0070] In this embodiment, the spray gun 31 is a dual-fluid nozzle, which can solve the technical bottleneck of single-fluid nozzles under high dust, strong corrosion and variable load conditions of waste incineration, so that the SNCR system can achieve the optimal balance between efficiency, reliability and economy, and meet the current environmental protection standards for emissions.

[0071] This embodiment also provides an incineration system, which includes a primary combustion chamber, a conveying pipeline, a secondary combustion chamber 1, and the aforementioned denitrification system. The primary combustion chamber is used to incinerate waste. The flue gas output from the primary combustion chamber is fed into the secondary combustion chamber 1 via the conveying pipeline, allowing the secondary combustion chamber 1 to continue burning unburned combustible gases. The denitrification system is used to inject atomized urea solution into the secondary combustion chamber 1, so that the atomized urea solution mixes with the flue gas in the secondary combustion chamber 1. With this configuration, the primary and secondary combustion chambers 1 undergo staged combustion. The primary combustion chamber suppresses the initial formation of nitrogen oxides, while the secondary combustion chamber 1 uses high-temperature turbulent flow to treat unburned gases and decompose dioxins, creating optimal conditions for denitrification. Furthermore, the aforementioned denitrification system can improve atomization and mixing efficiency, thereby enhancing pollutant control effectiveness and operational reliability.

[0072] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A denitrification system, characterized in that, It includes a secondary combustion chamber (1), a preparation unit (2), and an injection unit (3), wherein: The secondary combustion chamber (1) is used to burn the flue gas and maintain the temperature of the flue gas within a preset temperature range; The preparation unit (2) is used to prepare urea solution; The spraying unit (3) includes a spray gun (31) disposed on the top of the secondary combustion chamber (1). The spray gun (31) is connected to the preparation unit (2) through a delivery pipeline to atomize the urea solution output by the preparation unit (2) and spray it into the secondary combustion chamber (1).

2. The denitration system according to claim 1, wherein The preparation unit (2) includes: Urea preparation tank (21) is used to contain urea particles and water so that the urea particles dissolve in the water; A stirrer (22) is disposed inside the urea preparation tank (21), the stirrer (22) being configured to stir urea particles and water to prepare a urea solution; A heater (23) is disposed inside the urea preparation tank (21) and the heater (23) is configured to heat the inner cavity of the urea preparation tank (21).

3. The denitration system according to claim 2, wherein The preparation unit (2) further includes: A urea storage tank (24) is connected at one end to the urea preparation tank (21) and at the other end to the spray gun (31). The urea storage tank (24) is used to store the urea solution in the urea preparation tank (21). Two urea transfer pumps (25) are connected in parallel between the urea preparation tank (21) and the urea storage tank (24). The urea transfer pumps (25) are configured to transport the urea solution in the urea preparation tank (21) to the urea storage tank (24).

4. The denitration system according to claim 3, wherein The preparation unit (2) further includes: A dilution water supply unit (26) is connected to the urea preparation tank (21) and is used to supply water to the urea preparation tank (21); Adjustment component (27) is used to adjust the amount of water supplied by the dilution water supply component (26).

5. The system of claim 1, wherein, The secondary combustion chamber (1) includes a cylinder (11), a flue gas outlet (12), a flue gas inlet (13), and a combustion furnace (14), wherein: The cylinder (11) has a processing chamber inside, and the spray gun (31) is located at the top of the processing chamber; The flue gas outlet (12) is located at the upper part of the cylinder (11), and the flue gas inlet (13) is located at the lower part of the cylinder (11). The flue gas output from the first combustion chamber is supplied into the processing chamber through the flue gas inlet (13), and the flue gas processed by the second combustion chamber (1) is discharged from the processing chamber through the flue gas outlet (12). The combustion furnace (14) is disposed on the cylinder (11) and is configured to mix and ignite air with the flue gas supplied by the flue gas inlet (13).

6. The system of claim 5, wherein the system further comprises a catalyst bed disposed in the exhaust gas flow path downstream of the injector. The combustion furnace (14) and the spray gun (31) are connected to the same air supply pipeline (4), and the spray gun (31) atomizes the urea solution by compressing the air supplied by the air supply pipeline (4).

7. The system of claim 6, wherein the system further comprises a catalyst bed disposed in the exhaust gas flow path downstream of the injector. The combustion furnace (14) is located at the lower part of the cylinder (11).

8. The system of claim 1, wherein, The injection unit (3) includes a plurality of spray guns (31) distributed on the top of the secondary combustion chamber (1).

9. A denitrification system according to claim 1, characterized in that, The spray gun (31) is a dual-fluid nozzle.

10. An incineration system, characterized in that, It includes a primary combustion chamber, a delivery pipeline, a secondary combustion chamber (1), and the denitrification system according to any one of claims 1-9, wherein: The first combustion chamber is used to incinerate waste. The flue gas output from the first combustion chamber is fed into the second combustion chamber (1) through the conveying pipeline so that the second combustion chamber (1) can continue to burn unburned combustible gas. The denitrification system is used to spray atomized urea solution into the secondary combustion chamber (1) so that the atomized urea solution mixes with the flue gas in the secondary combustion chamber (1).

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