Low-nitrogen combustion device for flue gas recirculation
By designing the Venturi mixing tube assembly and the secondary mixing mechanism, the problem of uneven mixing of flue gas and air in the flue gas recirculation low-NOx combustion device was solved, achieving a more efficient combustion process and lower NOx emissions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANDONG JUJIA ENVIRONMENTAL PROTECTION TECH CO LTD
- Filing Date
- 2025-04-16
- Publication Date
- 2026-04-28
AI Technical Summary
Existing flue gas recirculation low-NOx combustion devices are inefficient when mixing flue gas with air, resulting in uneven oxygen distribution, the formation of localized high-temperature hotspots, and an increase in the formation of thermal NOx.
The system employs a Venturi mixing tube assembly combined with a gas equalization and delivery mechanism and a secondary mixing mechanism, along with a small cyclone dust collector, flue gas regulating valve, and flow detector. Multiple air delivery pipes and mixing fan blade assemblies are used to uniformly deliver and secondary mix flue gas and air, ensuring uniform gas distribution within the combustion zone.
It improves the mixing efficiency of flue gas and air, reduces local high-temperature hot spots, reduces NOx generation, extends equipment life, improves combustion efficiency and gas purity, and optimizes the combustion process.
Smart Images
Figure CN224175156U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of combustion equipment technology, specifically to a low-NOx combustion device for flue gas recirculation. Background Technology
[0002] A flue gas recirculation (FGR) low-NOx combustion device is a device used to reduce nitrogen oxide (NOx) emissions during combustion. Its main function is to reduce NOx formation by reintroducing some of the combusted flue gas into the combustion zone, thereby lowering the combustion temperature and oxygen concentration.
[0003] Existing low-NOx combustion devices with flue gas recirculation mainly consist of a flue gas extraction device, a mixing chamber, a recirculation fan, and a control system. Although they can achieve certain emission reduction effects in actual use, the mixing chambers in most low-NOx combustion devices are relatively simple, mostly using straight pipes or simple flared structures, allowing flue gas and air to mix naturally through turbulence. The mixing efficiency during actual mixing is poor, which easily leads to uneven oxygen distribution in the combustion zone, forming local high-temperature hot spots, which in turn exacerbates the formation of thermal NOx. Utility Model Content
[0004] This invention proposes a low-NOx combustion device for flue gas recirculation, which solves the problem in the prior art of low-NOx combustion devices for flue gas recirculation that have poor mixing efficiency between flue gas and air during flue gas recirculation.
[0005] The technical solution of this utility model is as follows: A low-NOx combustion device for flue gas recirculation includes a circulation frame, a gas pump, and a secondary mixing mechanism. A Venturi mixing tube assembly is provided on the circulation frame, and a gas equalization conveying mechanism for flue gas conveying is connected to the Venturi mixing tube assembly. The gas pump is installed on the circulation frame, and the outlet end of the gas pump is connected to one end of the Venturi mixing tube assembly through a gas delivery bend. The secondary mixing mechanism is installed on the circulation frame and extends through the Venturi mixing tube assembly to perform secondary acceleration and mixing of the gas in the Venturi mixing tube assembly.
[0006] As a preferred technical solution of this application, the gas equalization conveying mechanism includes a gas equalization ring pipe and a small cyclone dust collector. The gas equalization ring pipe is sleeved on the Venturi mixing pipe assembly. Several gas delivery pipes are connected at equal angles between the gas equalization ring pipe and the Venturi mixing pipe assembly. The small cyclone dust collector is installed on the Venturi mixing pipe assembly and is used to remove impurities from the flue gas entering the small cyclone dust collector. Two flue gas inlet pipe assemblies are symmetrically arranged and connected between the exhaust end of the small cyclone dust collector and the gas equalization ring pipe.
[0007] Furthermore, based on the aforementioned scheme, the flue gas inlet pipe assembly includes a flue gas inlet pipe, a flue gas regulating valve, and a flue gas flow detector. The flue gas inlet pipe is connected between the exhaust end of the small cyclone dust collector and the gas equalization ring pipe. The flue gas regulating valve is installed on the flue gas inlet pipe to regulate the flue gas flow rate through the flue gas inlet pipe. The flue gas flow detector is installed on the flue gas inlet pipe to detect the gas flow rate through the flue gas inlet pipe.
[0008] As a preferred technical solution of this application, the secondary gas mixing mechanism includes a gas mixing rotor, two gas mixing fan blade assemblies, and a gas mixing motor. The gas mixing rotor passes through and is rotatably mounted on the gas delivery bend. One end of the gas mixing rotor extends into the Venturi mixing tube assembly. The gas mixing fan blade assemblies are mounted on the gas mixing rotor and located within the Venturi mixing tube assembly. The gas mixing motor is mounted on one side of the circulation frame, and the output end of the gas mixing motor is connected to one end of the gas mixing rotor.
[0009] Based on the aforementioned scheme, the Venturi mixing tube assembly includes a throat and two diffusers. The throat is connected to the air supply pipe. The two diffusers are symmetrically and connected on both sides of the throat. The diffusers are mounted on the circulation frame. The equalization ring pipe and the small cyclone dust collector are both mounted on the diffusers. The diffusers correspond one-to-one with the mixing fan blade assembly, and the mixing fan blade assembly is located inside the diffuser.
[0010] Furthermore, based on the aforementioned scheme, one end of the diffuser tube away from the throat tube is connected to the gas supply bend, and the other end of the diffuser tube away from the throat tube is connected to the exhaust pipe.
[0011] Furthermore, based on the aforementioned scheme, a gas-mixing dispersion frame is provided inside the exhaust pipe, and one end of the gas-mixing rotating rod is rotatably mounted on the gas-mixing dispersion frame.
[0012] The beneficial effects of this utility model are as follows:
[0013] 1. In this utility model, a Venturi mixing tube assembly is combined with a gas equalization conveying mechanism. The gas equalization ring pipe is connected to the Venturi mixing tube assembly at equal angles through multiple gas delivery pipes. This can evenly deliver the flue gas into the Venturi mixing tube assembly, ensuring that the flue gas is evenly distributed in the tube assembly. This creates good conditions for subsequent full mixing with air and greatly improves the mixing efficiency.
[0014] 2. In this utility model, by setting a secondary gas mixing mechanism, the gas mixing fan blade assembly rotates inside the diffuser tube, which can not only stir the gas, but also further promote the secondary acceleration and mixing of the gas, allowing the flue gas and air to mix more fully, but also accelerate the passage of the mixed gas through the exhaust pipe, thereby increasing the reaction rate of the combustibles in the combustion zone.
[0015] 3. In this utility model, by setting a small cyclone dust collector, impurities in the incoming flue gas can be effectively removed. This not only avoids the accumulation of impurities in the combustion device, reduces wear on the internal parts of the equipment, and extends the service life of the equipment, but also ensures the purity of the gas participating in combustion, which helps to improve combustion efficiency and reduce the generation of pollutants.
[0016] 4. In this utility model, by setting up a flue gas inlet pipe group, the flue gas regulating valve can flexibly adjust the flue gas flow rate through the flue gas inlet pipe according to the actual combustion requirements, ensuring that the flue gas flow rate entering the Venturi mixing pipe group is appropriate, and the flue gas flow detector can monitor the gas flow rate in real time, providing accurate data for regulation, so that the entire combustion device can operate under the optimal gas flow rate and velocity conditions, which is conducive to optimizing the combustion process and reducing the emission of pollutants such as nitrogen oxides.
[0017] 5. In this utility model, the gas-mixing dispersion rack installed in the exhaust pipe can disperse the mixed gas, making the exhaust gas diffuse more evenly into the combustion area, reducing the situation of excessively high local gas concentration. Furthermore, the fact that one end of the gas-mixing rod is rotatably mounted on the gas-mixing dispersion rack further ensures the stability of the rotation of the gas-mixing rod, which helps to maintain the normal working state of the secondary gas-mixing mechanism. Attached Figure Description
[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0019] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0020] Figure 2 This utility model Figure 1 A magnified structural diagram of part A in the middle;
[0021] Figure 3 This is a schematic diagram of the structure of the Chinese-language mixing pipe assembly and the gas equalization and conveying mechanism of this utility model.
[0022] Figure 4 This is a partial cross-sectional structural diagram showing the cooperation between the Chinese-language mixing tube assembly and the secondary mixing mechanism of this utility model.
[0023] Figure 5 This is a structural schematic diagram of the entire utility model from another angle.
[0024] In the diagram: 001, Venturi mixing tube assembly; 002, gas equalization and conveying mechanism; 003, secondary gas mixing mechanism; 004, small cyclone dust collector;
[0025] 1. Circulation frame; 2. Gas pump; 3. Gas bend; 4. Gas equalization ring pipe; 5. Gas delivery pipe; 6. Flue gas inlet pipe; 7. Flue gas regulating valve; 8. Flue gas flow detector; 9. Mixing rod; 10. Mixing fan blade assembly; 11. Mixing motor; 12. Throat pipe; 13. Diffuser; 14. Exhaust pipe; 15. Mixed gas dispersion frame. Detailed Implementation
[0026] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this utility model.
[0027] like Figures 1-5 As shown in the figure, this embodiment proposes a low-NOx combustion device for flue gas recirculation, including a circulation frame 1, a gas pump 2, and a secondary mixing mechanism 003.
[0028] As mentioned above, the circulation frame 1 is equipped with a Venturi mixing tube assembly 001, and a gas equalization conveying mechanism 002 for flue gas conveying is connected to the Venturi mixing tube assembly 001.
[0029] The gas equalization conveying mechanism 002 includes a gas equalization ring pipe 4 and a small cyclone dust collector 004. The gas equalization ring pipe 4 is sleeved on the Venturi mixing pipe assembly 001. Several air supply pipes 5 are connected at equal angles between the gas equalization ring pipe 4 and the Venturi mixing pipe assembly 001. The small cyclone dust collector 004 is installed on the Venturi mixing pipe assembly 001 and is used to remove impurities from the flue gas entering the small cyclone dust collector 004. Two flue gas inlet pipe assemblies are symmetrically arranged and connected between the exhaust end of the small cyclone dust collector 004 and the gas equalization ring pipe 4.
[0030] Specifically, by setting up a small cyclone dust collector 004, impurities in the incoming flue gas can be effectively removed. This not only prevents impurities from accumulating in the combustion device, reducing wear on internal components and extending the service life of the equipment, but also ensures the purity of the gas participating in combustion, which helps to improve combustion efficiency and reduce the generation of pollutants. After the flue gas is cleaned by the small cyclone dust collector 004, it enters the gas equalization ring pipe 4 through the flue gas inlet pipe group, so that the flue gas enters the Venturi mixing pipe group 001 evenly through the evenly arranged air delivery pipes 5.
[0031] like Figure 4 As shown above, the small cyclone dust collector 004 is a commonly used device for removing impurities from flue gas in the prior art. Its specific structure is not the main innovation of this application, and its specific structure will not be described in detail here. As long as it can remove impurities from the flue gas, it is sufficient.
[0032] The flue gas inlet pipe assembly includes a flue gas inlet pipe 6, a flue gas regulating valve 7, and a flue gas flow detector 8. The flue gas inlet pipe 6 is connected between the exhaust end of the small cyclone dust collector 004 and the gas equalization ring pipe 4. The flue gas regulating valve 7 is installed on the flue gas inlet pipe 6 to regulate the flue gas flow rate through the flue gas inlet pipe 6. The flue gas flow detector 8 is installed on the flue gas inlet pipe 6 to detect the gas flow rate through the flue gas inlet pipe 6.
[0033] Specifically, the flue gas regulating valve 7 can flexibly adjust the flue gas flow rate through the flue gas inlet pipe 6 according to the actual combustion requirements, ensuring that the flue gas flow rate entering the Venturi mixing tube group 001 is appropriate. The flue gas flow detector 8 can monitor the gas flow rate in real time, providing accurate data for regulation, so that the entire combustion device can operate under the optimal gas flow rate and velocity conditions, which is conducive to optimizing the combustion process and reducing the emission of pollutants such as nitrogen oxides.
[0034] As mentioned above, the air pump 2 is installed on the circulation frame 1, and the air outlet of the air pump 2 is connected to one end of the Venturi mixing tube assembly 001 through the air supply bend 3.
[0035] Specifically, by starting the air pump 2, outside air can be pumped into the Venturi mixing pipe through the air bend 3, causing the air to flow inside the Venturi mixing pipe.
[0036] like Figure 5 As shown, the secondary gas mixing mechanism 003 is installed on the circulation frame 1 and is disposed through the Venturi mixing tube assembly 001. It is used to accelerate and mix the gas in the Venturi mixing tube assembly 001 for a second time. The secondary gas mixing mechanism 003 includes a gas mixing rotor 9, two gas mixing fan blade assemblies 10 and a gas mixing motor 11. The gas mixing rotor 9 is disposed through and rotatably mounted on the gas delivery bend 3. One end of the gas mixing rotor 9 extends into the Venturi mixing tube assembly 001. The gas mixing fan blade assembly 10 is disposed on the gas mixing rotor 9 and located in the Venturi mixing tube assembly 001. The gas mixing motor 11 is installed on one side of the circulation frame 1, and the output end of the gas mixing motor 11 is connected to one end of the gas mixing rotor 9.
[0037] Specifically, the mixing motor 11 is started, and the output end of the mixing motor 11 drives the mixing rod 9 to rotate. The rotation of the mixing rod 9 drives the mixing fan blade assembly 10 to rotate, which not only stirs the gas, but also further promotes the secondary acceleration and mixing of the gas, allowing the flue gas and air to blend more fully.
[0038] It should be further explained that the Venturi mixing tube assembly 001 mentioned above includes a throat 12 and two diffuser tubes 13. The throat 12 is connected to the air supply pipe 5. The two diffuser tubes 13 are symmetrically and connected on both sides of the throat 12. The diffuser tubes 13 are set on the circulation frame 1. The equalization ring pipe 4 and the small cyclone dust collector 004 are both set on the diffuser tubes 13. The diffuser tubes 13 correspond one-to-one with the mixing fan blade assembly 10. The mixing fan blade assembly 10 is located inside the diffuser tubes 13.
[0039] Specifically, when air enters the throat 12 through the diffuser 13, the gas velocity increases and the air pressure inside the throat 12 decreases. The flue gas then enters the throat 12 through the small cyclone dust collector 004, the flue gas inlet pipe 6, the equalization ring pipe 4, and the air supply pipe 5, causing the flue gas to mix with the air.
[0040] As described above, one end of one diffuser 13 away from the throat 12 is connected to the gas supply bend 3, and the other end of the diffuser 13 away from the throat 12 is connected to the exhaust pipe 14. A gas mixture dispersion rack 15 is provided inside the exhaust pipe 14, and one end of the gas mixture rotating rod 9 is rotatably mounted on the gas mixture dispersion rack 15.
[0041] Specifically, the air pumped in by the gas pump 2 enters the diffuser 13 through the gas bend 3, causing the flue gas and air to mix in the throat 12. When the mixed gas passes through the gas dispersion rack 15, it can also be dispersed, so that the discharged gas is more evenly diffused into the combustion area, reducing the situation of excessively high local gas concentration. Furthermore, one end of the gas mixing rod 9 is rotatably mounted on the gas dispersion rack 15, which further ensures the stability of the rotation of the gas mixing rod 9 and helps to maintain the normal working state of the secondary gas mixing mechanism 003.
[0042] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.
Claims
1. A low-NOx combustion device for flue gas recirculation, characterized in that, include: A circulation frame (1) is provided with a Venturi mixing tube assembly (001), and a gas equalization conveying mechanism (002) for flue gas conveying is connected to the Venturi mixing tube assembly (001). An air pump (2) is installed on the circulation frame (1), and the outlet end of the air pump (2) is connected to one end of the Venturi mixing tube assembly (001) through an air delivery bend (3). A secondary gas mixing mechanism (003) is installed on the circulation frame (1) and extends through the Venturi mixing tube assembly (001) to perform secondary acceleration and mixing of the gas in the Venturi mixing tube assembly (001).
2. The low-NOx combustion device for flue gas recirculation according to claim 1, characterized in that, The gas equalization conveying mechanism (002) includes: A gas equalization ring pipe (4) is sleeved on the Venturi mixing pipe assembly (001), and a number of gas delivery pipes (5) are connected at equal angles between the gas equalization ring pipe (4) and the Venturi mixing pipe assembly (001). A small cyclone dust collector (004) is installed on the Venturi mixing tube assembly (001). The exhaust end of the small cyclone dust collector (004) and the gas equalization ring tube (4) are symmetrically and connected to each other, and two flue gas inlet tube assemblies are provided.
3. The low-NOx combustion device for flue gas recirculation according to claim 2, characterized in that, The flue gas inlet pipe assembly includes: The flue gas inlet pipe (6) is connected between the exhaust end of the small cyclone dust collector (004) and the gas equalization ring pipe (4); A flue gas regulating valve (7) is installed on the flue gas inlet pipe (6); A flue gas flow detector (8) is installed on the flue gas inlet pipe (6).
4. The low-NOx combustion device for flue gas recirculation according to claim 3, characterized in that, The secondary mixing mechanism (003) includes: A mixing rod (9) is installed through and rotatably on the gas delivery bend (3), with one end of the mixing rod (9) extending into the Venturi mixing tube assembly (001); Two mixing fan blade assemblies (10) are mounted on the mixing rotor (9) and located within the Venturi mixing tube assembly (001); A gas mixing motor (11) is installed on one side of the circulation frame (1), and the output end of the gas mixing motor (11) is connected to one end of the gas mixing rotor (9).
5. The low-NOx combustion device for flue gas recirculation according to claim 4, characterized in that, The Venturi mixing tube assembly (001) includes: The throat tube (12) is connected to the air supply tube (5); Two diffuser tubes (13) are symmetrically and connected on both sides of the throat tube (12). The diffuser tubes (13) are set on the circulation frame (1). The gas equalization ring tube (4) and the small cyclone dust collector (004) are both set on the diffuser tubes (13). The diffuser tubes (13) correspond one-to-one with the gas mixing fan blade group (10). The gas mixing fan blade group (10) is located inside the diffuser tubes (13).
6. The low-NOx combustion device for flue gas recirculation according to claim 5, characterized in that, One of the diffuser tubes (13) is connected to the gas supply bend (3) at one end away from the throat tube (12), and the other diffuser tube (13) is connected to the exhaust tube (14) at one end away from the throat tube (12).
7. The low-NOx combustion device for flue gas recirculation according to claim 6, characterized in that, A gas-mixing diffuser (15) is provided inside the exhaust pipe (14), and one end of the gas-mixing rotating rod (9) is rotatably mounted on the gas-mixing diffuser (15).