Flue gas internal circulation structure suitable for hydrogen-doped fuel gas burner
By setting baffles to guide the flue gas in the flue gas internal circulation structure of the gas burner, the problem of stratified flow of flue gas and air is solved, achieving better mixing effect and NOx emission control.
Patent Information
- Application Number
- CN202520160229.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-23
- Publication Date
- 2026-01-27
- Estimated Expiration
- 2035-01-23
AI Technical Summary
In existing gas burners, flue gas and air mix in a stratified flow, resulting in poor mixing, excessively high flame temperature, and high levels of thermal NOx emissions.
In the flue gas internal circulation structure of a gas burner, baffles are set on the inner wall to guide the flue gas and make it fully mix with the air. The design of the baffles prevents the flue gas from flowing along the inner wall and dilutes the oxygen concentration before the air and flue gas mix, thereby reducing the flame temperature.
It achieves thorough mixing of flue gas and air, reduces flame temperature, effectively suppresses the formation of thermal NOx, and improves combustion efficiency and mixing effect.
Smart Images
Figure CN223840362U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of gas burner technology, specifically to a flue gas internal circulation structure suitable for a gas burner with hydrogen-blended fuel. Background Technology
[0002] A gas burner is a device that mixes gas and air for combustion to generate heat or provide power. Gas burners are widely used in homes, businesses, and industries, such as household gas stoves, industrial boilers, and gas generator sets. The basic structure of a gas burner includes a gas supply system, an air supply system, a combustion chamber, and a control system. The gas supply system is responsible for delivering gas to the burner and typically includes gas pipes, pressure regulating valves, and gas nozzles. The air supply system is responsible for introducing air into the burner and typically includes a fan, air intake pipes, and air regulating valves. The combustion chamber is the area where gas and air are mixed and burned, and typically includes the combustion chamber walls and gas nozzles inside the combustion chamber. The control system is responsible for monitoring and adjusting the ratio of gas to air, as well as controlling parameters such as temperature and pressure during the combustion process.
[0003] Among the many ways of burning gaseous fuels, flue gas recirculation is recognized as a simple and efficient combustion method. However, its high flame temperature during combustion results in high thermal NOx emissions, which limits its large-scale application.
[0004] In existing technologies, flue gas and air are generally mixed before combustion, which can reduce the combustion temperature and reduce NOx formation. However, the flue gas flows along the inner wall of the channel at a low speed, which can easily lead to the separation of flue gas and air, resulting in poor mixing.
[0005] In summary, existing methods of mixing flue gas and air result in stratified flow of the flue gas and air, leading to poor mixing performance. Utility Model Content
[0006] The purpose of this invention is to solve the problem of poor mixing effect caused by the stratified flow of flue gas and air during the mixing of flue gas and air. Therefore, it provides a flue gas internal circulation structure suitable for gas burners using hydrogen-blended fuels.
[0007] The technical solution of this utility model is: a flue gas internal circulation structure suitable for a gas burner with hydrogen-blended fuel, comprising: a central fuel channel, an air channel and a main fuel channel arranged sequentially from the inside to the outside, a mixing channel arranged downstream of the air channel, the air channel communicating with the mixing channel, and a flue gas channel communicating with the mixing channel between the air channel and the mixing channel.
[0008] The inner wall of the mixing channel is provided with baffles distributed circumferentially to guide the flue gas and ensure that the flue gas and air are fully mixed.
[0009] Furthermore, the cross-section of the block is trapezoidal, and the inclined surface of the trapezoid is located on the side close to the air passage.
[0010] Furthermore, the stop has a plurality of blocks evenly distributed along the circumference.
[0011] Furthermore, the stop block is a continuous structure distributed circumferentially.
[0012] Furthermore, the inlet and outlet of the mixing channel are respectively provided with diffusers extending outward.
[0013] Furthermore, the air passage outlet is provided with a constricted portion extending inward.
[0014] Furthermore, the central fuel passage, the air passage, and the flue gas passage are arranged coaxially.
[0015] Furthermore, the main fuel channel has multiple channels evenly distributed circumferentially around the central fuel channel.
[0016] Furthermore, the main fuel channel and the central fuel channel are coaxially arranged.
[0017] Compared with the prior art, the present invention has the following advantages:
[0018] 1. The flue gas internal circulation structure for a gas burner with hydrogen-blended fuel provided by this utility model has a baffle on the inner wall of the mixing channel. The baffle guides the flue gas, prevents the flue gas from flowing along the inner wall of the mixing channel, and ensures that the flue gas and air are fully mixed, avoiding the situation of flue gas and air flowing in layers.
[0019] 2. The flue gas internal circulation structure for a gas burner with hydrogen-blended fuel provided by this utility model has a small resistance between the inclined surface of the baffle and the flue gas when the flue gas is guided, which facilitates the flow of flue gas and makes the flue gas flow faster.
[0020] 3. The flue gas internal circulation structure for a gas burner with hydrogen-blended fuel provided by this utility model mixes the air with the flue gas before it comes into contact with the central fuel, diluting the oxygen concentration in the air, slowing down the mixing speed of oxygen and fuel, thereby reducing the flame temperature and effectively suppressing the formation of thermal NOx. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the overall structure of the flue gas internal circulation structure of the gas burner suitable for hydrogen-blended fuel according to this utility model.
[0022] Figure 2 yes Figure 1 Side view of the middle stop block in the first embodiment;
[0023] Figure 3 yes Figure 1 Side view of the middle block in the second embodiment.
[0024] In the diagram: 1. Central fuel passage; 2. Air passage; 3. Flue gas passage; 4. Main fuel passage; 5. Mixing passage; 6. Baffle; 7. Diffusion section; 8. Narrowing section. Detailed Implementation
[0025] Specific implementation method one: Combining Figure 1 This embodiment describes a central fuel channel 1, an air channel 2, and a main fuel channel 4 arranged sequentially from the inside out. A mixing channel 5 is located downstream of the air channel 2, and the air channel 2 is connected to the mixing channel 5. A flue gas channel 3, connected to the mixing channel 5, is located between the air channel 2 and the mixing channel 5. Baffles 6 are arranged circumferentially on the inner wall of the mixing channel 5 to guide the flue gas and ensure thorough mixing of the flue gas and air. The entire burner nozzle must be made of high-temperature resistant materials, such as 316 stainless steel. The height of the baffles 6 should ensure that the flow area of the air mixing channel 5 at that location is greater than the flow area of the straight section of the air channel 2 to ensure smooth flow of the mixed gas.
[0026] The flue gas internal circulation structure of this embodiment, applicable to gas burners with hydrogen-blended fuels, has a baffle 6 installed on the inner wall of the mixing channel 5. The baffle 6 guides the flue gas, preventing it from flowing along the inner wall of the mixing channel 5, thus ensuring that the flue gas and air are fully mixed and avoiding the situation of flue gas and air flowing in layers.
[0027] Specific Implementation Method Two: Combining Figure 1 This embodiment differs from Specific Embodiment 1 in that the cross-section of the baffle 6 is trapezoidal, with the inclined surface of the trapezoid located on the side closest to the air passage 2. Two trapezoids are symmetrically distributed. When the inclined surface of the baffle 6 guides the flue gas, the resistance between them is small, facilitating the flow of the flue gas and increasing its speed. Other components and connections are the same as in Specific Embodiment 1.
[0028] Specific implementation method three: Combining Figure 2 This embodiment differs from specific embodiment one in that the baffles 6 are multiple and evenly distributed circumferentially. These baffles 6 are spaced apart to guide the flue gas, and each baffle 6 is independent, facilitating later maintenance. Other components and connections are the same as in specific embodiment one.
[0029] Specific implementation method four: Combination Figure 3 This embodiment differs from specific embodiment one in that the baffle 6 is a continuous structure distributed circumferentially. The baffle 6 is arranged in a ring on the inner wall of the mixing channel 5, resulting in a wider guiding area and better guiding effect for the flue gas. Other components and connections are the same as in specific embodiment one.
[0030] Specific Implementation Method Five: Combining Figure 1 This embodiment differs from Specific Embodiment 1 in that the mixing channel 5 has outwardly extending diffusers 7 at both its inlet and outlet. These diffusers 7 are annular, providing a larger area for gas collection and emission. When a large amount of flue gas and air enters the mixing channel 5, the flow rate of the mixed gas increases, improving flow efficiency. Other components and connections are the same as in Specific Embodiment 1.
[0031] Specific Implementation Method Six: Combination Figure 1 This embodiment differs from specific embodiment five in that the outlet of air channel 2 has an inwardly extending constriction 8, which is also annular. This constriction 8 allows the air in air channel 2 to flow concentratedly into mixing channel 5. With the combined action of diffuser 7 and constriction 8, the gas flow is improved. The angle between the constriction 8 at the outlet of air channel 2 and the central axis is A, which is not greater than 45°. The angle between the diffuser 7 at the inlet of mixing channel 5 and the central axis is B, which is not less than A. The angle between the diffuser 7 at the outlet of mixing channel 5 and the central axis is C, which should be between 15° and 60°. Other components and connections are the same as in specific embodiment five.
[0032] Specific implementation method seven: Combination Figure 1 This embodiment differs from specific embodiment one in that the central fuel channel 1, air channel 2, and flue gas channel 3 are coaxially arranged. This arrangement ensures uniform gaps between the channels, even gas flow, and facilitates channel positioning and assembly. Other components and connections are the same as in any of specific embodiments one through six.
[0033] Specific implementation method eight: Combination Figure 2 , Figure 3 This embodiment differs from specific embodiment seven in that the main fuel channel 4 has multiple channels evenly distributed circumferentially around the central fuel channel 1. The main fuel channel 4 is multi-channel, evenly distributed around the air channel 2. This dispersed arrangement of the main flame ensures uniform flame distribution, avoids concentrated flames and localized high temperatures, and thus reduces the formation of thermal NOx. The number of central fuel channels 1 can be 3-16. Other components and connections are the same as in specific embodiment seven.
[0034] Specific Implementation Method Nine: Combining Figure 2 , Figure 3 This embodiment differs from specific embodiment seven in that the main fuel channel 4 and the central fuel channel 1 are coaxially arranged. This arrangement facilitates the positioning of the main fuel channel 4 and the central fuel channel 1. Other components and connections are the same as in specific embodiment seven.
[0035] The working principle of this implementation method is as follows:
[0036] The air in the air passage 2 flows to the central fuel passage 1 and the main fuel passage 4 respectively. Some of the air flows through the constriction section 8 and the diffuser section 7 and then enters the mixing passage 5. The flue gas flows through the diffuser section 7 and then enters the mixing passage 5. The baffle 6 on the inner wall of the mixing passage 5 guides the flue gas and prevents it from flowing along the inner wall of the mixing passage 5, so that the flue gas and air in the mixing passage 5 are fully mixed, the combustion temperature is lower, and thus the NOx emission level is reduced.
[0037] The content of this utility model is not limited to the above-described embodiments; a combination of one or more specific embodiments can also achieve the purpose of the utility model.
Claims
1. A flue gas internal recirculation structure suitable for a gas burner using hydrogen-blended fuel, comprising: A central fuel passage (1), an air passage (2), and a main fuel passage (4) are arranged sequentially from the inside out. A mixing passage (5) is arranged downstream of the air passage (2). The air passage (2) is connected to the mixing passage (5). A flue gas passage (3) connected to the mixing passage (5) is arranged between the air passage (2) and the mixing passage (5). The characteristic feature is that the inner wall of the mixing channel (5) is provided with baffles (6) distributed in the circumferential direction, and the baffles (6) guide the flue gas to make the flue gas and air fully mixed.
2. The flue gas internal recirculation structure for a gas burner suitable for hydrogen-blended fuels according to claim 1, characterized in that, The cross-section of the block (6) is trapezoidal, and the inclined surface of the trapezoid is located on the side close to the air passage (2).
3. The flue gas internal recirculation structure for a gas burner suitable for hydrogen-blended fuels according to claim 1, characterized in that, The stop (6) has a plurality of blocks evenly distributed along the circumference.
4. The flue gas internal recirculation structure for a gas burner suitable for hydrogen-blended fuels according to claim 1, characterized in that, The stop block (6) is a continuous structure distributed along the circumference.
5. The flue gas internal recirculation structure for a gas burner suitable for hydrogen-blended fuels according to claim 1, characterized in that, The mixing channel (5) is provided with a diffuser (7) extending outward at its inlet and outlet.
6. The flue gas internal recirculation structure for a gas burner suitable for hydrogen-blended fuels according to claim 5, characterized in that, The air passage (2) has a constricted section (8) extending inward at its outlet.
7. A flue gas internal recirculation structure suitable for a gas burner using hydrogen-blended fuel according to any one of claims 1-6, characterized in that, The central fuel passage (1), the air passage (2), and the flue gas passage (3) are arranged coaxially.
8. The flue gas internal recirculation structure for a gas burner suitable for hydrogen-blended fuels according to claim 7, characterized in that, The main fuel channel (4) has a plurality of channels evenly distributed circumferentially around the central fuel channel (1).
9. The flue gas internal recirculation structure for a gas burner suitable for hydrogen-blended fuels according to claim 7, characterized in that, The main fuel channel (4) is coaxially arranged with the central fuel channel (1).