An ultra-low nitrogen burner for hydrogen / natural gas

Abstract

The invention discloses an ultra-low nitrogen burner for hydrogen / natural gas, comprising a hydrogen gas collecting chamber, a hydrogen outer gas gun, a hydrogen inner gas gun, a natural gas gas collecting chamber, a natural gas central gas gun, a natural gas middle gas gun, a natural gas outer gas gun and a combustion stabilizing cover; the hydrogen gas collecting chamber is provided with a hydrogen outer gas gun and a hydrogen inner gas gun, the hydrogen outer gas gun and the hydrogen inner gas gun are provided with a natural gas collecting chamber, the natural gas collecting chamber is provided with a natural gas outer gas gun, the hydrogen outer gas gun and the hydrogen inner gas gun are provided with a natural gas central gas gun, the natural gas central gas gun is provided with a natural gas middle gas gun, the natural gas middle gas gun is provided with a combustion stabilizing cover, the hydrogen gas collecting chamber and the natural gas gas collecting chamber are respectively fed with air without interfering with each other, the center flame temperature is reduced by two sets of gas pipelines, fuel grading, rich-lean combustion, and a small amount of flue gas external circulation (FGR) measures, thereby ensuring stable combustion of the burner and, under the condition that the two gases operate separately, stable combustion and ultra-low NOx emissions are guaranteed.

Description

Technical Field

[0001] The present invention relates to an ultra-low nitrogen burner, in particular to an ultra-low nitrogen burner suitable for hydrogen / natural gas. Background Art

[0002] With the development of society and the economy, environmental issues are receiving increasing attention. Global warming is the result of human-induced climate change. "Carbon" refers to natural resources such as oil, coal, and wood, which are composed of carbon. Increased carbon consumption leads to increased production of "carbon dioxide," the culprit for global warming. As a result of human activities, global warming is changing (affecting) people's lifestyles and causing increasing problems.

[0003] In accordance with the guiding opinions on accelerating the establishment and improvement of a green, low-carbon, circular development economic system, we will promote green planning, green design, green investment, green construction, green production, green circulation, green life, and green consumption in all aspects and throughout the entire process, so that development is based on efficient resource utilization, strict protection of the ecological environment, and effective control of greenhouse gas emissions. We will coordinate the promotion of high-quality development and high-level protection, establish and improve a green, low-carbon, circular development economic system, ensure the achievement of carbon peak and carbon neutrality goals, and promote my country's green development to a new level.

[0004] In this context, ultra-low nitrogen burners must not only meet the requirements of low nitrogen emissions, but also the requirements of low carbon emissions. This requires ultra-low nitrogen burners to be able to use hydrogen as fuel, but due to the instability of hydrogen supply, the development of an ultra-low nitrogen burner that can meet the conditions of use of natural gas (or other gases) as fuel and hydrogen as fuel has become an urgent requirement. According to the content of GB / T41664-2022 "Evaluation Methods and Test Rules for Low NOx Oil and Gas Burners", burners with NOx≤30mg / Nm3 are Class 1 low NOx burners (the highest level). How to further reduce NOx emissions and achieve low-carbon goals is a major problem that urgently needs to be solved in this field.

[0005] The ultra-low nitrogen burners currently in use are generally only suitable for natural gas (or other fuel gases). When a second fuel is added, they cannot meet the working conditions of multi-fuel switching, or cannot simultaneously meet the low nitrogen emission requirements when using two fuels and different loads. Therefore, continuing to develop a new dual-fuel ultra-low nitrogen burner is the direction of scientific research researchers' efforts. Summary of the Invention

[0006] Technical problem: The purpose of the present invention is to overcome the shortcomings of the existing technology and provide an ultra-low nitrogen burner for hydrogen / natural gas that has a simple structure, is easy to use, and can achieve the dual goals of low carbon and low nitrogen.

[0007] Technical solution: An ultra-low nitrogen burner for hydrogen / natural gas of the present invention comprises a hydrogen gas collecting chamber, a hydrogen outer layer gas gun, a hydrogen inner layer gas gun, a natural gas gas collecting chamber, a natural gas central gas gun, a natural gas middle layer gas gun, a natural gas outer layer gas gun and a combustion stabilizing cover; a plurality of hydrogen outer layer gas guns and a plurality of hydrogen inner layer gas guns connected to the hydrogen gas collecting chamber are alternately and evenly distributed on the outer circumference of the right end portion of the hydrogen gas collecting chamber, a natural gas gas collecting chamber is set on the outer circumference of the plurality of hydrogen outer layer gas guns and the plurality of hydrogen inner layer gas guns, a plurality of natural gas outer layer gas guns uniformly distributed on the periphery of the plurality of hydrogen outer layer gas guns and the plurality of hydrogen inner layer gas guns are provided on the circumference of the right end surface of the natural gas gas collecting chamber, a plurality of hydrogen outer layer gas guns and A natural gas central gas gun connected to a natural gas gas collecting chamber is provided in the middle of the multiple hydrogen inner gas guns. A multiple natural gas middle gas guns connected to the natural gas central gas gun and arranged in a circle are provided in the middle of the natural gas middle gas guns. A combustion stabilizing cover with an arc-shaped front end is provided at the front of the multiple natural gas middle gas guns. The gas nozzle of the hydrogen outer gas gun is a porous structure. The porous structure sprays at a certain angle along the burner nozzle diameter. The gas nozzle of the hydrogen outer gas gun is arranged obliquely and sprays at a certain angle tangential to the circumference along the rotation direction of the combustion stabilizing cover blades. The hydrogen gas collecting chamber and the natural gas gas collecting chamber are respectively fed with air without interfering with each other. When the two gases are operated separately, they burn stably and ensure ultra-low NOx emissions.

[0008] The number of the multiple hydrogen outer layer gas guns is 4 to 8 and they are evenly distributed around the circumference.

[0009] The number of the multiple hydrogen inner layer gas guns is 4 to 8 and they are evenly distributed around the circumference.

[0010] The jet angle of the porous structure fuel gas nozzle of the hydrogen outer layer gas gun is 15 to 60 degrees.

[0011] The fuel gas nozzle of the hydrogen outer layer gas gun is along the rotation direction of the combustion stabilizing cover blades, and the angle of the circumferential tangential injection is 15 to 45 degrees.

[0012] The number of the plurality of natural gas middle layer gas guns is 4 to 8 and they are evenly distributed around the circumference.

[0013] The number of the multiple natural gas outer layer air guns is 6 to 16 and they are evenly distributed around the circumference.

[0014] Beneficial effects: To achieve the dual goals of low carbon and low nitrogen, further reduce NOx emissions, optimize the burner structure, and achieve the low carbon goal; the present invention uses a hydrogen air gun assembly, a natural gas air gun assembly, and a stable combustion cover assembly. Through two sets of gas pipelines, it ensures the stable combustion of natural gas, while also ensuring the stable combustion of hydrogen or hydrogen + natural gas, and ensuring that each other does not increase NOx emissions; the two components do not interfere with each other, and ensure that any gas can burn stably and achieve ultra-low NOx emissions under the condition of single operation. Fuel grading, rich and thin combustion, a small amount of flue gas recirculation (FGR) and other measures are used to reduce the temperature of the central flame, ensuring stable combustion of the burner, while achieving free switching between the two fuels and reducing the emission value of thermal nitrogen oxides (NOx), making NOx ≤ 30mg / m3 (3% O2@FGR). According to the content of GB / T41664-2022, burners with NOx≤30mg / Nm3 are level 1 low NOx burners (the highest level). The ultra-low nitrogen burner of hydrogen / natural gas of the present invention can reduce NOx emissions to ≤15mg / Nm3, achieving ultra-low NOx emissions, while reducing carbon dioxide emissions and achieving the goal of carbon reduction and low carbon. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the cross-sectional structure of the ultra-low nitrogen burner of the present invention.

[0016] Figure 2 It is a schematic diagram of the three-dimensional structure of the ultra-low nitrogen burner of the present invention.

[0017] Figure 3 It is a schematic diagram of the external circulation of flue gas of the ultra-low nitrogen burner of the present invention.

[0018] In the figure: 1-hydrogen gas collecting chamber, 2-hydrogen outer layer gas gun, 3-hydrogen inner layer gas gun, 4-natural gas gas collecting chamber, 5-natural gas center gas gun, 6-natural gas middle layer gas gun, 7-natural gas outer layer gas gun, 8-stable combustion cover. DETAILED DESCRIPTION

[0019] An embodiment of the present invention will be further described below with reference to the accompanying drawings:

[0020] like Figure 1 Figure 2As shown, the ultra-low nitrogen burner for hydrogen / natural gas of the present invention is mainly composed of a hydrogen gas collecting chamber (1), a hydrogen outer layer gas gun (2), a hydrogen inner layer gas gun (3), a natural gas gas collecting chamber (4), a natural gas center gas gun (5), a natural gas middle layer gas gun (6), a natural gas outer layer gas gun (7) and a combustion stabilizing cover (8); a plurality of hydrogen outer layer gas guns (2) and a plurality of hydrogen inner layer gas guns (3) connected to the hydrogen gas collecting chamber (1) are alternately and evenly distributed on the outer circumference of the right end of the hydrogen gas collecting chamber (1), the plurality of hydrogen outer layer gas guns (2) are 4 to 8 in number and are evenly distributed around the circumference; the plurality of hydrogen inner layer gas guns (3) are 4 to 8 in number and are evenly distributed around the circumference. A natural gas collecting chamber (4) is mounted on the outer circumference of the plurality of hydrogen outer layer gas guns (2) and the plurality of hydrogen inner layer gas guns (3). A plurality of natural gas outer layer gas guns (7) are uniformly distributed around the outer circumference of the plurality of hydrogen outer layer gas guns (2) and the plurality of hydrogen inner layer gas guns (3). A natural gas central gas gun (5) connected to the natural gas collecting chamber (4) is provided in the middle of the plurality of hydrogen outer layer gas guns (2) and the plurality of hydrogen inner layer gas guns (3). The number of the plurality of natural gas outer layer gas guns (7) is 6 to 16 and is uniformly distributed around the circumference. The middle of the natural gas central gas gun (5) is provided with a plurality of natural gas middle layer gas guns (6) connected to the natural gas middle layer gas gun (5) and arranged in a circumference. The front of the plurality of natural gas middle layer gas guns (6) is provided with a combustion stabilizing cover (8) with an arc-shaped front end. The number of the plurality of natural gas middle layer gas guns (6) is 4 to 8 and is uniformly distributed around the circumference. The gas nozzle of the hydrogen outer layer gas gun (2) is a porous structure, and the porous structure sprays at a certain angle along the burner nozzle diameter. The spray angle of the porous structure gas nozzle of the hydrogen outer layer gas gun (2) is 15 to 60 degrees. The gas nozzle of the hydrogen outer layer gas gun (3) is arranged obliquely, and sprays at a certain angle of circumferential tangent along the rotation direction of the blade of the combustion stabilizing cover (8); the gas nozzle of the hydrogen outer layer gas gun (3) sprays at an angle of 15 to 45 degrees along the rotation direction of the blade of the combustion stabilizing cover (8). The above-mentioned hydrogen gas collecting chamber (1), hydrogen outer layer gas gun (2) and hydrogen inner layer gas gun (3) are a component; and the natural gas gas collecting chamber (4), natural gas center gas gun (5), natural gas middle layer gas gun (6), natural gas outer layer gas gun (7) and combustion stabilizing cover (8) are a component. The hydrogen inner layer gas guns (3) and the natural gas middle layer gas guns (6) are arranged in a staggered manner on the circumference; the hydrogen outer layer gas guns (2), the hydrogen inner layer gas guns (3), the natural gas middle layer gas guns (6) and the natural gas outer layer gas guns (7) are all evenly distributed on the circumference, and the number of the natural gas outer layer gas guns (7) is controlled to be 6 to 16; the hydrogen gas collecting chamber (1) and the natural gas gas collecting chamber (4) are respectively fed with air without interfering with each other, and under the condition of the two gases operating separately, stable combustion is achieved and ultra-low NOx emissions are guaranteed.

[0021] Working principle of ultra-low nitrogen burner for hydrogen / natural gas:

[0022] 1) Fuel classification

[0023] According to the low-nitrogen combustion principle, when the NO generated during combustion encounters hydrocarbon radicals CHi, incomplete combustion products CO, H2, C and CnHm, a NO reduction reaction will occur.

[0024] Utilizing this principle, the fuel depth is divided into two or three levels. The first-stage fuel is injected into the primary combustion zone, where α>>1. Excess combustion air is used to control the average temperature of the primary combustion zone below 1500°C, strictly controlling the generation of thermal NOx. The second-stage fuel is injected from the periphery of the primary combustion zone into the middle and rear portion of the zone, forming a secondary combustion zone. In this secondary combustion zone, the secondary fuel is mixed and burned with flue gas with an oxygen concentration below 12%. The relatively high concentrations of CHi and CO reduce the trace NOx generated in the primary combustion zone, further reducing NOx emissions.

[0025] 2) Rich-Lean Combustion

[0026] The principle of rich-lean combustion is as follows: in the flame area, a part of the fuel is used for rich combustion (compared to lean combustion, the fuel is relatively more), and the other part of the fuel is used for lean combustion, which divides a flame into multiple small flames. Since the small flames have a large heat dissipation area and a low flame temperature, they can significantly reduce the thermal NOx generated by combustion. In addition, the small flames shorten the residence time of the gas in the flame, which has a significant inhibitory effect on both thermal NOx and rapid NOx.

[0027] The second principle of rich-lean combustion is that part of the first-stage fuel mixes with the first-stage combustion air in a swirling flow, forming a dense phase zone (central recirculation zone) that enables stable combustion. The other part of the fuel mixes with the second-stage combustion air (the air outside the combustion stabilization hood) in a direct flow, forming a lean phase combustion zone. This lean phase combustion zone has a large amount of excess combustion air, thereby reducing the temperature of the main combustion area.

[0028] 3) Flue gas external circulation

[0029] like Figure 3As shown, the flue gas at the boiler's tail is drawn into the burner bellows by a flue gas recirculation fan or a combustion-supporting fan, where it is thoroughly mixed with the combustion-supporting air, reducing the oxygen concentration of the combustion-supporting air. Furthermore, the externally circulated flue gas entering the combustion zone can significantly reduce the flame temperature, fuel concentration, and oxygen concentration in the combustion zone, thereby significantly reducing the generation of thermal NOx and rapid NOx. By employing combustion staging and rich-lean combustion techniques, the average temperature of the main combustion zone is controlled below 1400 degrees Celsius, and the flame is divided into multiple small flames, making the flame more diffuse. This effectively reduces the flame zone temperature and strictly controls the generation of thermal NOx and rapid NOx. Therefore, when using a small amount of external flue gas recirculation, the flame temperature can be further reduced, and the generation of thermal NOx and rapid NOx will also be further reduced.

[0030] By deeply integrating low-nitrogen technologies such as fuel staging, rich-lean combustion, and flue gas recirculation, the hydrogen / natural gas ultra-low-nitrogen burner can ensure flue gas NOx emissions of less than 30mg / Nm3 (3.0% O2 content). This technology has been verified through trials and projects, achieving the expected results.

Claims

1. An ultra-low nitrogen burner for hydrogen / natural gas, characterized by: The invention comprises a hydrogen gas collecting chamber (1), a hydrogen outer layer gas gun (2), a hydrogen inner layer gas gun (3), a natural gas gas collecting chamber (4), a natural gas central gas gun (5), a natural gas middle layer gas gun (6), a natural gas outer layer gas gun (7) and a combustion stabilizing cover (8); a plurality of hydrogen outer layer gas guns (2) and a plurality of hydrogen inner layer gas guns (3) connected to the hydrogen gas collecting chamber (1) are alternately and evenly distributed on the outer circumference of the right end portion of the hydrogen gas collecting chamber (1); a natural gas gas collecting chamber (4) is mounted on the outer circumference of the plurality of hydrogen outer layer gas guns (2) and the plurality of hydrogen inner layer gas guns (3); a plurality of natural gas outer layer gas guns (7) uniformly distributed on the periphery of the plurality of hydrogen outer layer gas guns (2) and the plurality of hydrogen inner layer gas guns (3) are arranged on the circumference of the right end face of the natural gas collecting chamber (4); a plurality of hydrogen outer layer gas guns (2) and a plurality of hydrogen inner layer gas guns (3) are alternately and evenly distributed on the periphery of the plurality of hydrogen outer layer gas guns (2) and the plurality of hydrogen inner layer gas guns (3); A natural gas central gas gun (5) connected to a natural gas collecting chamber (4) is provided in the middle of the hydrogen inner gas gun (3); a plurality of natural gas middle gas guns (6) connected to the natural gas central gas gun (5) and arranged in a circle are provided in the middle of the natural gas middle gas gun (5); a combustion stabilizing cover (8) with an arc-shaped front end is provided at the front of the plurality of natural gas middle gas guns (6); the gas nozzle of the hydrogen outer gas gun (2) is a porous structure, which sprays at a certain angle along the burner nozzle diameter; the gas nozzle of the hydrogen inner gas gun (3) is arranged obliquely and sprays at a certain angle in the circumferential direction along the rotation direction of the blade of the combustion stabilizing cover (8); the hydrogen collecting chamber (1) and the natural gas collecting chamber (4) are respectively fed with air without interfering with each other, and the two gases can stably burn and ensure ultra-low NOx emissions under separate operating conditions.

2. The ultra-low nitrogen burner for hydrogen / natural gas according to claim 1, characterized in that: The number of the plurality of hydrogen outer layer gas guns (2) is 4 to 8 and they are evenly distributed around the circumference.

3. The ultra-low nitrogen burner for hydrogen / natural gas according to claim 1, characterized in that: The number of the multiple hydrogen inner layer air guns (3) is 4 to 8 and they are evenly distributed around the circumference.

4. The ultra-low nitrogen burner for hydrogen / natural gas according to claim 1, characterized in that: The angle of the porous structure fuel gas nozzle of the hydrogen outer layer gas gun (2) is 15-60 degrees.

5. The ultra-low nitrogen burner for hydrogen / natural gas according to claim 1, characterized in that: The fuel gas nozzle of the hydrogen inner layer gas gun (3) is arranged along the rotation direction of the blades of the combustion stabilizing cover (8) at a circumferential tangential injection angle of 15 to 45 degrees.

6. The ultra-low nitrogen burner for hydrogen / natural gas according to claim 1, characterized in that: The number of the plurality of natural gas middle layer gas guns (6) is 4 to 8 and they are evenly distributed around the circumference.

7. The ultra-low nitrogen burner for hydrogen / natural gas according to claim 1, characterized in that: The number of the plurality of natural gas outer layer air guns (7) is 6 to 16 and they are evenly distributed around the circumference.

Images