Ammonia burner with ammonia catalytic decomposition function

Abstract

The utility model discloses an ammonia burner with an ammonia catalytic decomposition function, which comprises a burner shell, an ammonia gas pipeline is arranged in the burner shell, an air outlet of the ammonia gas pipeline is positioned inside the front end of the burner shell, an air inlet of the ammonia gas pipeline is positioned outside the burner shell, and an air inlet for injecting air into the burner shell is arranged on the burner shell. A catalyst for heating and decomposing ammonia gas is arranged in the ammonia gas pipeline; a guide vane used for providing air for gas at the gas outlet of the ammonia gas pipeline and wrapping the gas at the gas outlet of the ammonia gas pipeline to move towards the outer portion of the front end of the combustor shell is arranged in the combustor shell. The ammonia gas is heated and decomposed into hydrogen and nitrogen through a catalyst in the ammonia gas pipeline, efficient combustion of the ammonia is achieved, generation of high nitrogen oxide is avoided, the outlet end of the ammonia gas pipeline is provided with a certain chamfer, and a local high-temperature area in front of the outlet end of the ammonia gas pipeline is avoided in cooperation with guiding of the guide vanes on the wind direction. And damage to the combustor and generation of high nitrogen oxides are caused.

Description

Technical Field

[0001] This utility model relates to the field of burner technology, specifically to an ammonia burner with ammonia catalytic decomposition function. Background Technology

[0002] Carbon-free alternative fuels are an effective way to reduce carbon dioxide emissions. Among them, ammonia fuel has attracted attention from many industries such as power, transportation, and industry due to its advantages such as high hydrogen density, safe and convenient transportation and storage, and a mature production-transportation-distribution system. Compared with traditional fossil fuels, ammonia fuel has a higher minimum ignition energy and a slower flame propagation speed. At the same time, as a "high-nitrogen" fuel, ammonia combustion has a potential tendency to generate high levels of nitrogen oxides. The demand for ammonia burners is urgent, the requirements are high, and the challenges are significant. The structural design of the burner is crucial to achieving efficient and stable combustion of ammonia fuel and low nitrogen oxide emissions. Therefore, it is essential to design a burner adapted to ammonia fuel to achieve better ignition, combustion, and burnout characteristics.

[0003] Chinese patent document (CN112902163A) discloses a hydrogen-doped low-NOx combustion system and method based on ammonia decomposition, which improves the combustion heat release rate and reduces nitrogen oxide emissions. However, this patent document requires the setting of two combustion zones. This results in a complex burner structure, high manufacturing difficulty, difficult maintenance, and large installation and usage space requirements.

[0004] Chinese patent document (CN113864775A) discloses an ammonia-blended multiphase fuel staged swirl burner, which can ensure the stability of ammonia combustion and improve combustion efficiency. However, the burner has many pipes installed inside for transporting fuel and air, and the internal structure of the combustion chamber is complex.

[0005] Chinese patent document (CN114110572A) discloses a preheating ammonia combustion method and system with ultrasonic synergistic control, providing a new solution to the problem of low flammability of ammonia. It achieves stable combustion of ammonia at a preheated temperature of 320℃, reduces nitrogen oxide emissions, and improves flame speed and temperature. However, this combustion system requires combining preheating components and ultrasonic components to preheat the ammonia fuel before ignition, resulting in a complex structure and low operational reliability.

[0006] It can be seen that most existing ammonia burners achieve efficient and stable combustion of ammonia through relatively complex combustion chamber and piping structures. These ammonia combustion systems are all quite complex, difficult to maintain, and have low operational reliability. Utility Model Content

[0007] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide an ammonia burner that achieves efficient and stable combustion through the catalytic decomposition of ammonia.

[0008] To achieve this objective, the ammonia burner with ammonia catalytic decomposition function designed in this utility model includes a burner shell. An ammonia gas pipe with an outlet located inside the front end of the burner shell and an inlet located outside the burner shell is provided inside the burner shell. An air inlet for injecting air into the burner shell is provided on the burner shell. A catalyst for thermally decomposing ammonia gas is provided inside the ammonia gas pipe. Guide vanes are provided inside the burner shell to supply air to the gas at the outlet of the ammonia gas pipe and to guide the gas at the outlet of the ammonia gas pipe towards the front end of the burner shell.

[0009] Furthermore, the ammonia pipeline includes an axial ammonia pipeline coaxially disposed within the burner housing and a radial ammonia pipeline communicating with the front end of the axial ammonia pipeline.

[0010] Furthermore, one end of the axial ammonia pipe is located outside the burner housing, and the other end of the axial ammonia pipe is a closed structure located inside the front end of the burner housing. The end of the axial ammonia pipe located outside the burner housing is the inlet of the ammonia pipe, and the outlet of the ammonia pipe is located on the radial ammonia pipe.

[0011] Furthermore, the radial ammonia pipeline includes an inner radial ammonia pipeline and an outer radial ammonia pipeline coaxially arranged and fixedly connected to the axial ammonia pipeline; the inner radial ammonia pipeline is connected to the axial ammonia pipeline, the top of the outer radial ammonia pipeline is a closed structure, there is a gap between the top surface of the inner radial ammonia pipeline and the inner top surface of the outer radial ammonia pipeline, and the outlet of the ammonia pipeline is opened on the outer radial ammonia pipeline.

[0012] Furthermore, the surface of the outer radial ammonia pipe is provided with a plurality of ammonia pipe outlets spaced apart along its length, and the diameter of the ammonia pipe outlets increases sequentially from the side away from the axial ammonia pipe to the side closer to the axial ammonia pipe.

[0013] Furthermore, the catalyst is disposed on the inner surface of both the inner radial ammonia gas pipe and the inner surface of the outer radial ammonia gas pipe.

[0014] Furthermore, the guide vane has an annular structure, with its central part coaxially fixed to the axial ammonia pipeline, the outer surface of the guide vane fixed to the inner surface of the burner housing, and the guide vane located behind the radial ammonia pipeline.

[0015] Furthermore, the inner side of the guide vane is provided with a plurality of direct-flow air holes spaced apart along its circumferential direction for supplying air to the gas outlet of the ammonia pipeline.

[0016] Furthermore, the outer side of the guide vane is provided with a plurality of swirling air slots that extend from the outer surface of the guide vane toward the inner side of the guide vane and are used to wrap the gas at the outlet of the ammonia pipe and move it toward the outside of the front end of the burner housing.

[0017] Furthermore, the ratio of the ventilation area of ​​the DC air hole to the ventilation area of ​​the swirling air groove is 1:5 to 1:6.

[0018] The beneficial effects of this invention are as follows: The catalyst within the ammonia pipeline decomposes ammonia into hydrogen and nitrogen under heating, achieving efficient combustion of ammonia while preventing the formation of high-NOx oxides. The outlet end of the ammonia pipeline has a chamfer, which, combined with guide vanes, guides the airflow and prevents localized high-temperature zones in front of the ammonia pipeline outlet, thus avoiding burner damage and high-NOx oxide formation. This invention integrates the catalyst within the ammonia pipeline, resulting in a simple and compact structure, convenient maintenance, and avoiding complex internal piping designs in burners, thus ensuring high operational reliability. The ammonia burner designed in this invention can be applied to thermal power plants, achieving rapid and large-scale carbon reduction without requiring extensive structural modifications to existing boilers. It extends the service life of existing generator sets and solves the problem of premature generator set retirement due to carbon dioxide emission restrictions. Attached Figure Description

[0019] Figure 1 This is a perspective view of the ammonia burner with ammonia catalytic decomposition function in this utility model;

[0020] Figure 2 This is a perspective view of the connection structure between the ammonia pipeline and the guide vanes in this utility model;

[0021] Figure 3 This is a three-dimensional structural view of the ammonia pipeline in this utility model;

[0022] Figure 4 This is a three-dimensional view of the guide vane structure in this utility model;

[0023] Figure 5 This is a front view of the structure of the guide vane in this utility model;

[0024] Figure 6 This is a front view of the radial ammonia pipeline in this utility model;

[0025] Figure 7 This is a schematic diagram of the connection between the radial ammonia pipeline and the axial ammonia pipeline in this utility model;

[0026] Figure 8 This is a schematic diagram of gas flow in this utility model.

[0027] Wherein, 1—burner shell, 2—ammonia pipeline, 3—air inlet, 4—axial ammonia pipeline, 5—radial ammonia pipeline (5.1—inner radial ammonia pipeline, 5.2—outer radial ammonia pipeline), 6—guide vane, 7—direct current air hole, 8—swirl air slot. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0029] like Figure 1 —7 shows an ammonia burner with ammonia catalytic decomposition function, including a burner housing 1, an ammonia gas pipe 2 with an outlet located inside the front end of the burner housing 1 and an inlet located outside the burner housing 1, an air inlet 3 for injecting air into the burner housing 1, a catalyst for heating and decomposing ammonia gas inside the ammonia gas pipe 2, and a guide vane 6 inside the burner housing 1 for supplying air to the gas at the outlet of the ammonia gas pipe 2 and enveloping the gas at the outlet of the ammonia gas pipe 2 to move it to the front end of the burner housing 1.

[0030] like Figure 2 —3 and Figure 6As shown in Figure 7, the ammonia pipeline 2 includes an axial ammonia pipeline 4 coaxially disposed within the burner housing 1 and multiple radial ammonia pipelines 5 communicating with the front end of the axial ammonia pipeline 4. The multiple radial ammonia pipelines 5 are evenly distributed circumferentially along the front end of the axial ammonia pipeline 4. One end of the axial ammonia pipeline 4 is located outside the burner housing 1, and the other end of the axial ammonia pipeline 4 is a closed structure located inside the front end of the burner housing 1. The end of the axial ammonia pipeline 4 located outside the burner housing 1 is the inlet of the ammonia pipeline 2, and the outlet of the ammonia pipeline 2 is located on the radial ammonia pipelines 5. The radial ammonia pipeline 5 includes an inner radial ammonia pipeline 5.1 and an outer radial ammonia pipeline 5.2, coaxially arranged and fixedly connected to the axial ammonia pipeline 4. The inner radial ammonia pipeline 5.1 is connected to the axial ammonia pipeline 4, and the top of the outer radial ammonia pipeline 5.2 is a closed structure. There is a gap between the top surface of the inner radial ammonia pipeline 5.1 and the inner top surface of the outer radial ammonia pipeline 5.2. The outlet of the ammonia pipeline 2 is located on the outer radial ammonia pipeline 5.2. Multiple outlets of the ammonia pipeline 2 are spaced apart along the length of the surface of the outer radial ammonia pipeline 5.2. The diameter of the outlets of the ammonia pipeline 2 increases sequentially from the side furthest from the axial ammonia pipeline 4 to the side closer to the axial ammonia pipeline 4. This arrangement aims to increase the residence time of ammonia in the radial ammonia pipeline 5, thereby increasing the thermal catalytic decomposition effect of ammonia. The number of outlets of the ammonia pipeline 2 can be set to 4-10 as needed. Catalysts are provided on the inner surface of both the inner radial ammonia gas pipe 5.1 and the inner surface of the outer radial ammonia gas pipe 5.2. In this invention, the inner radial ammonia gas pipe 5.1 can be a multi-layer structure, and catalysts can be provided on each inner radial ammonia gas pipe 5.1 to increase the residence time of ammonia gas in the radial ammonia gas pipe 5, thereby further increasing the catalytic thermal decomposition effect of ammonia gas.

[0031] like Figure 4 As shown in Figure 5, the guide vane 6 has an annular structure, with its central part coaxially fixed to the axial ammonia pipe 4. The outer surface of the guide vane 6 is fixed to the inner surface of the burner housing 1, and the guide vane 6 is located behind the radial ammonia pipe 5. Multiple direct-flow air holes 7 are spaced apart along the circumferential direction on the inner side of the guide vane 6 to supply air to the gas outlet of the ammonia pipe 2. The direct-flow air holes 7 can be multi-layered annular direct-flow air hole groups spaced apart along the radial direction of the guide vane 6, with each group including multiple direct-flow air holes 7 spaced apart along the circumferential direction of the guide vane 6. Multiple swirling air grooves 8 are spaced apart along the circumferential direction on the outer side of the guide vane 6, extending from the outer surface of the guide vane 6 to the inner side of the guide vane 6, used to enclose the gas at the outlet of the ammonia pipe 2 and move it towards the front end of the burner housing 1. The number of swirling air grooves 8 is 8 to 20. Figure 5As shown, the swirling air groove 8 has an inclined surface tilted to one side, forming a swirling angle of 15° to 30°, causing the air passing through the swirling air groove 8 to form a swirling flow. The ratio of the ventilation area of ​​the direct-flow air hole 7 to the ventilation area of ​​the swirling air groove 8 is 1:6.

[0032] In this invention, ammonia gas enters through the inlet of the axial ammonia gas pipe 4, passes through the inner radial ammonia gas pipe 5.1 and the outer radial ammonia gas pipe 5.2, and then exits through the outlet of the ammonia gas pipe 2. As the ammonia gas passes through the ammonia gas pipe 2, the catalyst within the pipe decomposes it into hydrogen and nitrogen under heating, achieving both efficient combustion of ammonia and preventing the formation of high-nitrogen oxides. Figure 8 As shown, the outlet end of the ammonia pipeline 2 has a chamfer, which, together with the guide vanes 6, guides the airflow and prevents localized high-temperature zones in front of the outlet end of the ammonia pipeline 2, thus avoiding burner damage and the generation of high nitrogen oxides. This invention integrates the catalyst within the ammonia pipeline, resulting in a simple and compact structure, convenient maintenance, and avoiding complex internal piping designs for the burner, thus ensuring high operational reliability. The ammonia burner designed in this invention can be applied to thermal power plants to achieve rapid and large-scale carbon reduction without requiring extensive structural modifications to existing boilers. It extends the service life of existing generator sets and solves the problem of premature generator set retirement due to carbon dioxide emission restrictions.

[0033] The above description is merely a preferred embodiment of the present utility model and does not constitute any limitation on the structure of the present utility model. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1. An ammonia combustor having an ammonia catalytic decomposition function, comprising a combustor housing (1), characterized by: The burner shell (1) is provided with an ammonia gas pipeline (2) with an air outlet inside the front end of the burner shell (1) and an air inlet outside the burner shell (1), and the burner shell (1) is provided with an air inlet (3) for injecting air into the inside of the burner shell (1); the ammonia gas pipeline (2) is provided with a catalyst for heating and decomposing ammonia gas; the burner shell (1) is provided with a guide vane (6) for providing air to the gas at the air outlet of the ammonia gas pipeline (2) and wrapping the gas at the air outlet of the ammonia gas pipeline (2) to move to the outside of the front end of the burner shell (1).

2. The ammonia combustor having an ammonia catalytic decomposition function according to claim 1, characterized by: The ammonia gas pipeline (2) comprises an axial ammonia gas pipeline (4) coaxially arranged in the burner shell (1) and a radial ammonia gas pipeline (5) in communication with the front end of the axial ammonia gas pipeline (4).

3. The ammonia combustor having an ammonia catalytic decomposition function according to claim 2, characterized by: One end of the axial ammonia gas pipeline (4) is located outside the burner shell (1), and the other end of the axial ammonia gas pipeline (4) is a closed structure arranged inside the front end of the burner shell (1); the end of the axial ammonia gas pipeline (4) located outside the burner shell (1) is the air inlet of the ammonia gas pipeline (2), and the air outlet of the ammonia gas pipeline (2) is formed on the radial ammonia gas pipeline (5).

4. The ammonia combustor having an ammonia catalytic decomposition function according to claim 3, characterized by: The radial ammonia gas pipeline (5) comprises an inner radial ammonia gas pipeline (5.1) and an outer radial ammonia gas pipeline (5.2) coaxially arranged and fixedly connected to the axial ammonia gas pipeline (4); the inner radial ammonia gas pipeline (5.1) is in communication with the axial ammonia gas pipeline (4), the top of the outer radial ammonia gas pipeline (5.2) is a closed structure, and there is a gap between the top surface of the inner radial ammonia gas pipeline (5.1) and the inner top surface of the outer radial ammonia gas pipeline (5.2); the air outlet of the ammonia gas pipeline (2) is formed on the outer radial ammonia gas pipeline (5.2).

5. The ammonia combustor having an ammonia catalytic decomposition function according to claim 4, characterized by: A plurality of air outlets of the ammonia gas pipeline (2) are formed on the surface of the outer radial ammonia gas pipeline (5.2) at intervals along the length direction of the outer radial ammonia gas pipeline (5.2); the hole diameters of the air outlets of the ammonia gas pipeline (2) gradually increase from the side away from the axial ammonia gas pipeline (4) to the side close to the axial ammonia gas pipeline (4).

6. The ammonia combustor having an ammonia catalytic decomposition function according to claim 4 or 5, characterized by: The catalyst is arranged on the inner surface of the inner radial ammonia gas pipeline (5.1) and the inner surface of the outer radial ammonia gas pipeline (5.2).

7. The ammonia combustor having an ammonia catalytic decomposition function according to claim 3, characterized by: The guide vane (6) is in a ring structure, the middle part of the guide vane (6) is coaxially fixed to the axial ammonia gas pipeline (4), the outer surface of the guide vane (6) is fixed to the inner surface of the burner shell (1), and the guide vane (6) is located behind the radial ammonia gas pipeline (5).

8. The ammonia combustor having an ammonia catalytic decomposition function according to claim 7, characterized by: A plurality of straight air holes (7) for providing air to the gas at the air outlet of the ammonia gas pipeline (2) are formed on the inner side of the guide vane (6) at intervals along the circumferential direction of the guide vane (6).

9. The ammonia combustor having an ammonia catalytic decomposition function according to claim 8, characterized by: The outer side of the guide vane (6) is provided with a plurality of swirl air grooves (8) spaced apart along the circumferential direction thereof, which extend from the outer side surface of the guide vane (6) to the inner side of the guide vane (6) and are used for wrapping the gas outlet of the ammonia gas pipeline (2) to move the gas to the outside of the front end of the combustor shell (1).

10. The ammonia combustor having an ammonia catalytic decomposition function according to claim 9, characterized by: The ratio of the air passage area of the straight-through air hole (7) to the air passage area of the swirl air groove (8) is 1:5-1:6.

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