Natural gas boiler low-nitrogen combustion device

Abstract

The natural gas boiler low-nitrogen combustion device comprises a boiler body and a heat exchange box, one end of the boiler body communicates with a smoke pipe, the other end of the smoke pipe penetrates through the heat exchange box and is connected with a treatment box, and a filter plate is arranged on the inner wall of the bottom of the treatment box, so that combustion smoke spirally ascends when entering the treatment box through the smoke pipe; the residence time of smoke in the treatment box is prolonged, the contact time of the smoke and spraying liquid is prolonged, the contact area of the smoke and the spraying liquid is increased, solid particles in the smoke are filtered through a filter plate, then accumulated dust and dirt on the inner wall of the boiler are reduced, a good combustion state is kept, and generation of nitric oxide is reduced. Before entering the burner, air firstly enters the heat exchange box to be preheated, and then flue gas, fuel gas and the air are mixed in the burner, so that the combustion effect of the fuel gas is improved, the required combustion temperature is reduced, and the generation of nitrogen oxides can be effectively reduced.

Description

Technical Field

[0001] This utility model relates to the field of natural gas boiler technology, and in particular to a low-NOx combustion device for natural gas boilers. Background Technology

[0002] Natural gas boilers, as the name suggests, are boilers that use natural gas as fuel. Compared to oil-fired and electric boilers, gas-fired boilers are the most economical, so most people choose them for steam, heating, and bathing. Currently, air pollution is becoming increasingly severe. Air pollution not only harms human health but also affects the harmony and stability of society and the ecological environment. Boiler flue gas contains nitrogen oxides, mainly nitric oxide and nitrogen dioxide, and nitrogen oxides are one of the causes of acid rain.

[0003] Chinese patent CN219453943U discloses an energy-saving, low-NOx natural gas combustion device. It utilizes flue gas recirculation to return a portion of the exhaust gas to the boiler, reducing the oxygen concentration in the mixture and preventing excessively high combustion temperatures, thereby inhibiting the formation of nitrogen oxides. However, the flue gas contains numerous impurities. If not cleaned promptly, the recirculation of the flue gas into the boiler leads to increased ash and scale buildup on the boiler's inner walls, hindering proper combustion and increasing nitrogen oxide emissions. Utility Model Content

[0004] The purpose of this application is to provide a low-NOx combustion device for a natural gas boiler to solve the problem that during the flue gas recirculation process, the flue gas contains a lot of impurities. If these impurities are not cleaned in time, the flue gas will accumulate more ash and dirt on the inner wall of the boiler after recirculation, making it impossible to maintain a good combustion state, resulting in an increase in nitrogen oxides and hindering nitrogen oxide emissions.

[0005] To address the aforementioned technical problems, this application provides a low-NOx combustion device for a natural gas boiler, comprising a boiler body and a heat exchange box. One end of the boiler body is connected to a flue gas pipe, and the other end of the flue gas pipe passes through the heat exchange box and is connected to a treatment box. A heat transfer fluid is disposed inside the heat exchange box. A spray pipe is disposed on one side of the treatment box, and a pump is disposed on the spray pipe. The other end of the spray pipe extends into the treatment box and is connected to a spray head. A filter plate is fixedly disposed on the bottom inner wall of the treatment box, and the filter plate is disposed close to the flue gas pipe. An outlet pipe is disposed on the top of the treatment box, and a circulation pipe is fixedly connected to one side of the outlet pipe. A burner is connected to the other end of the circulation pipe, and a control valve is disposed on the circulation pipe. A gas pipe and an air inlet pipe are connected to the outside of the burner, and the burner is connected to the boiler body through a connecting pipe.

[0006] In a preferred embodiment, the filter plate is provided in two layers along the inner wall of the treatment box.

[0007] In a preferred embodiment, a rotating shaft is also provided on the top of the treatment box, the rotating shaft is rotatably connected to the inner wall of the treatment box, and a plurality of activated carbon meshes are provided on the surface of the rotating shaft.

[0008] In a preferred embodiment, the other end of the air inlet pipe passes through the heat exchange box.

[0009] In a preferred embodiment, the flue gas pipe and air inlet pipe inside the heat exchange box are both arranged in a continuous U-shape.

[0010] In a preferred embodiment, the heat exchange box is made of polystyrene board.

[0011] Compared with the prior art, the beneficial effects of this application are:

[0012] 1. A filter plate is installed on the bottom inner wall of the treatment box, so that the combustion smoke spirals upward when it enters the treatment box through the flue gas pipe. This increases the residence time of the smoke in the treatment box, the contact time between the smoke and the spray liquid, and the contact area between the smoke and the spray liquid. The filter plate filters out solid particles in the smoke, that is, it purifies the recirculated flue gas, reduces impurities in the flue gas during recirculation, thereby reducing ash and dirt accumulation on the inner wall of the boiler, maintaining a good combustion state, and helping to reduce the generation of nitrogen oxides.

[0013] 2. Before entering the burner, the air first enters the heat exchange box for preheating. Then, the flue gas, fuel gas, and air are mixed in the burner, which improves the combustion efficiency of the fuel gas, lowers the required combustion temperature, and thus effectively reduces the generation of nitrogen oxides. Attached Figure Description

[0014] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0015] Figure 1 A schematic diagram of a low-NOx combustion device for a natural gas boiler provided by this utility model;

[0016] Figure 2 A schematic diagram of a filter plate and a treatment box structure provided by this utility model;

[0017] In the diagram: 1. Boiler body; 2. Flue gas pipe; 3. Heat exchange box; 4. Treatment box; 5. Spray pipe; 6. Pump; 7. Spray head; 8. Filter plate; 9. Rotating shaft; 10. Activated carbon mesh; 11. Gas outlet pipe; 12. Circulation pipe; 13. Control valve; 14. Air inlet pipe; 15. Gas pipe; 16. Burner; 17. Connecting pipe. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0019] The core of this application is to provide a low-NOx combustion device for a natural gas boiler, which solves the problem that during the flue gas recirculation process, the flue gas contains a lot of impurities. If these impurities are not cleaned in time, the flue gas will accumulate more ash and dirt on the inner wall of the boiler after recirculation, making it impossible to maintain a good combustion state, resulting in an increase in nitrogen oxides and hindering nitrogen oxide emissions.

[0020] Figure 1 This utility model provides an external structural diagram of a low-NOx combustion device for a natural gas boiler. Figure 2 An internal structural diagram of a low-NOx combustion device for a natural gas boiler provided by this utility model is shown below. Figures 1 to 2 As stated above.

[0021] A low-NOx combustion device for a natural gas boiler includes a boiler body 1 and a heat exchange box 3. The structure and working principle of the boiler body 1 can be found in the prior art. One end of the boiler body 1 is connected to a flue gas pipe 2, through which the combustion smoke generated inside the boiler body 1 is discharged. The other end of the flue gas pipe 2 passes through the heat exchange box 3 and is connected to a processing box 4. The heat exchange box 3 is filled with a heat transfer fluid. When the high-temperature combustion flue gas passes through the heat exchange box 3, it heats the heat transfer fluid, thereby making full use of the heat in the flue gas and improving the practicality of the device. A spray pipe 5 is connected to one side of the treatment box 4, and the other end of the spray pipe 5 is connected to a box containing alkaline solution. A pump 50 is installed on the spray pipe 5, which pumps the alkaline solution from the box into the treatment box 4. The other end of the spray pipe 5 extends into the treatment box 4 and is connected to a spray head 6. The spray head 6 is located inside the treatment box 4, with multiple spray heads 6 arranged in a ring above, so that the alkaline solution can cover the entire interior of the spray treatment box 4 when it falls, increasing the contact area between the alkaline solution and the flue gas. The alkaline solution is sprayed downwards through the spray head 6, mixing with the flue gas and removing acidic sulfur-containing substances from the flue gas. A filter plate 7 is fixedly installed on the bottom inner wall of the treatment box 4, and the filter plate 7 is arranged around the inner wall of the treatment box 4. The filter plate 7 is located close to the flue gas pipe 2. The flue gas entering the treatment box 4 from the flue gas pipe 2 is first filtered by the filter plate 7, and the filter plate 7 can reduce the rising speed of the flue gas and increase the spraying time.

[0022] The top of the treatment box 4 is connected to an exhaust pipe 10. The flue gas purified by spraying and filtration inside the treatment box 4 is discharged through the exhaust pipe 10. A circulation pipe 11 is fixedly connected to one side of the exhaust pipe 10, and a burner 15 is connected to the other end of the circulation pipe 11. Some of the flue gas flows to the discharge treatment pipe through the exhaust pipe 10, and some returns to the burner 15 through the circulation pipe 11. The specific structure of the burner 15 can be referred to Chinese Patent No. CN219453943U. A control valve 12 is provided on the circulation pipe 11. A gas pipe 14 and an air inlet pipe 13 are connected to the outside of the burner 15. The burner 15 is connected to the boiler body 1 through a connecting pipe 16. By using the burner 15 to fully mix the fuel gas, air, and combustion smoke, the oxygen content in the air added to the boiler body 1 can be reduced, the combustion temperature can be lowered, and the oxygen partial pressure during the reaction of nitrogen and oxygen can be reduced, thereby reducing the nitrogen oxide content in the exhaust gas. The emission ratio of the exhaust gas can be adjusted by changing the flue gas flow rate per unit time inside the circulation pipe 11 through the control valve 12.

[0023] Since the combustion flue gas moves rapidly upward when it enters the treatment box 4 through the flue gas pipe 2, in order to reduce the upward speed of the flue gas and thus increase the residence time of the flue gas in the treatment box 4, as a preferred embodiment, the filter plate 7 is provided with two layers along the inner wall of the treatment box 4. The two layers of filter plate 7 make the flue gas spiral upward, further reducing the upward speed of the flue gas, so that the particulate impurities in the flue gas settle more thoroughly.

[0024] To further reduce impurities and oxides in the recirculated flue gas, preferably, a rotating shaft 8 is also provided on the top of the treatment box 4. The rotating shaft 8 is rotatably connected to the inner wall of the treatment box 4. Multiple activated carbon meshes 9 are provided on the surface of the rotating shaft 8. The rotating shaft 8 is driven by an external driving device (not shown in the figure), which in turn drives the multiple sets of activated carbon meshes 9 on the rotating shaft 8 to rotate, so that the flue gas continuously contacts the activated carbon meshes 9, thereby adsorbing and filtering gaseous impurities and oxides, and purifying the flue gas.

[0025] In this embodiment, preferably, the other end of the air inlet pipe 13 extends through the heat exchange box 3. The high temperature of the flue gas after combustion can heat the heat transfer fluid in the heat exchange box. Before entering the burner 15, the air first enters the heat exchange box 3 for preheating. Then, in the burner 15, the flue gas, fuel gas, and air are mixed, improving the combustion efficiency of the fuel gas and lowering the required combustion temperature. This effectively reduces the generation of nitrogen oxides and improves environmental friendliness. Preferably, both the flue gas pipe 2 and the air inlet pipe 13 in the heat exchange box 3 are arranged in a continuous U-shape. The U-shape increases the contact area between the heat transfer fluid and the flue gas pipe 2 and the air inlet pipe 13, resulting in higher heat transfer efficiency.

[0026] Preferably, the heat exchange box 3 is made of polystyrene board. The polystyrene board material of the heat exchange box 3 further reduces energy loss, allowing for the reuse of the heat transfer fluid within the heat exchange box 3, thereby improving the efficiency of the device and reducing its energy consumption.

[0027] The low-NOx combustion device for a natural gas boiler provided in this application, in actual use, heats the heat transfer fluid as the high-temperature combustion flue gas passes through the heat exchange box 3. The heated flue gas then enters the treatment box 4, where a filter plate 7 is fixedly installed on the inner wall of the bottom. The filter plate 7 filters impurities in the flue gas. At the same time, the pump 50 is activated to pump the alkaline solution in the box into the treatment box 4. The alkaline solution is then atomized and sprayed out through the spray head 6. Multiple spray heads 6 are arranged in a ring above, so that the alkaline solution can cover the entire interior of the spray treatment box 4 when it falls, increasing the contact area between the alkaline solution and the flue gas, removing acidic sulfur-containing substances in the flue gas. The flue gas rises to the activated carbon mesh 9, and the rotating shaft 8 drives the activated carbon mesh 9 to rotate, adsorbing and filtering gaseous impurities and oxides, thus purifying the flue gas. After being sprayed and filtered in the treatment box 4, the flue gas is discharged through the outlet pipe 10. Part of the flue gas flows to the emission treatment pipeline through the outlet pipe 10, and part of it returns to the burner 15 through the circulation pipe 11. The burner 15 fully mixes the fuel gas, air and combustion smoke, which can reduce the oxygen content in the air added to the boiler body 1, reduce the combustion temperature, and reduce the oxygen partial pressure when nitrogen and oxygen react, thereby achieving the purpose of reducing the nitrogen oxide content in the emission flue gas.

[0028] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and incorporate common knowledge or customary techniques in the art disclosed herein. The specification and examples are to be considered exemplary only, and the true scope of this application is indicated by the claims.

[0029] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The embodiments of this application described above do not constitute a limitation on the scope of protection of this application.

Claims

1. A low-NOx combustion device for a natural gas boiler, characterized in that, include: The boiler body (1) and heat exchange box (3) are provided. One end of the boiler body (1) is connected to a flue gas pipe (2), and the other end of the flue gas pipe (2) passes through the heat exchange box (3) and is connected to a treatment box (4). The heat exchange box (3) is filled with heat transfer fluid. A spray pipe (5) is connected to one side of the treatment box (4). A pump (50) is installed on the spray pipe (5). The other end of the spray pipe (5) extends into the treatment box (4) and is connected to a spray head (6). The bottom inner wall of the treatment box (4) is fixedly provided with a... A filter plate (7) is arranged near the flue gas pipe (2). An outlet pipe (10) is connected to the top of the treatment box (4). A circulation pipe (11) is fixedly connected to one side of the outlet pipe (10). A burner (15) is connected to the other end of the circulation pipe (11). A control valve (12) is provided on the circulation pipe (11). A gas pipe (14) and an air inlet pipe (13) are connected to the outside of the burner (15). The burner (15) is connected to the boiler body (1) through a connecting pipe (16).

2. The low-NOx combustion device for a natural gas boiler according to claim 1, characterized in that, The filter plate (7) is provided in two layers along the inner wall of the processing box (4).

3. The low-NOx combustion device for a natural gas boiler according to claim 1, characterized in that, The top of the treatment box (4) is also provided with a rotating shaft (8), which is rotatably connected to the inner wall of the treatment box (4), and a plurality of activated carbon meshes (9) are provided on the surface of the rotating shaft (8).

4. The low-NOx combustion device for a natural gas boiler according to claim 1, characterized in that, The other end of the air inlet pipe (13) is installed through the heat exchange box (3).

5. The low-NOx combustion device for a natural gas boiler according to claim 4, characterized in that, The flue gas pipe (2) and air inlet pipe (13) inside the heat exchange box (3) are both arranged in a continuous U-shape.

6. The low-NOx combustion device for a natural gas boiler according to claim 4, characterized in that, The heat exchange box (3) is made of polystyrene board.

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