Low-nitrogen burner

Abstract

The present invention discloses a low-nitrogen burner, belonging to the technical field of kiln burners. In the first vortex mixing zone and the second vortex mixing zone, turbulence is formed due to the impact of various hot airflows in different directions. The turbulence enables the pre-mixing of combustible gas and combustion-supporting air, and reaches a fully mixed state in the third main fire mixing zone and enters the third main fire combustion zone, making the combustion reach a flameless combustion state. The third main fire combustion zone is the fully combustion area with the highest flame temperature among the three combustion zones. However, since the combustion-supporting air and gas supplied by the first and second-stage combustion areas are restricted, they are in an incomplete combustion state with a low flame temperature, ensuring that the first two stages cannot burn fully and have a low flame temperature, and do not have the conditions for generating nitrogen oxides. Although the temperature of the third-stage flame is high, the mixing is sufficient and the air-fuel ratio is precise, giving priority to the full combustion of the fuel, consuming all the oxygen, and making it impossible for nitrogen to be oxidized under the conditions of high temperature and lack of oxygen, thereby realizing the process of low-nitrogen combustion.

Description

Technical Field

[0001] The present invention relates to the technical field of kiln burners, and in particular to a low-nitrogen burner. Background Art

[0002] Kiln burners are used to burn gas to heat products in the kiln or to ignite the kiln. Existing conventional burners generally have only one-stage mixing. After the combustion-supporting air and gas are mixed, they are ignited. Due to uneven mixing, local high-temperature phenomena will occur after ignition, which easily causes nitrogen and oxygen to react to generate nitrogen oxides, such as air pollutants such as nitric oxide and nitrogen dioxide. Since there is only one-stage mixing, it is very easy to have uneven situations, which in turn leads to the generation of thermal nitrogen oxides, and even exceeds the standard. This requires strict control of the burner's split-flow and staged combustion process starting from the burner structure design in order to reduce or avoid the generation of thermal nitrogen oxides. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. For this reason, the present invention proposes a burner that realizes low-nitrogen combustion. The design concept is to change the one-stage mixed combustion of the conventional burner to multi-stage mixed combustion, reduce the flame temperature during the combustion process, and avoid or reduce the thermal nitrogen oxides generated by high temperature or local high temperature during the combustion process. The present invention divides the burner combustion process into three stages, and each stage has a corresponding combustion zone. The first vortex mixing zone and the second vortex mixing zone are both vortex-type annular mixing combustion zones. This vortex is determined by the physical structure of the burner. Its existence not only ensures the stability of the flame, but also causes the first annular combustion zone and the second annular combustion zone to release heat due to combustion. This heat simultaneously heats the gas inside the annular combustion zone and the combustion-supporting air outside, so that the third main fire mixing zone is carried out on the premise that the gas and the combustion-supporting air are simultaneously preheated and premixed. At the same time, in the first and second annular combustion zones, turbulence is formed due to the impact of various airflows in different directions. The turbulence makes the mixing more uniform and the combustion more complete, prompting the combustible gas and the combustion-supporting air to reach a fully mixed state in the third main fire mixing zone. That is to say, the burner structure determines the flameless combustion in the third main fire combustion zone. Therefore, the three-stage combustion structure of this burner ensures the low-nitrogen combustion process.

[0004] According to an embodiment of the present invention, the low-nitrogen burner includes:

[0005] An outer housing provided with a combustion-supporting air channel. The combustion-supporting air channel is provided with a combustion-supporting air inlet. The front end of the combustion-supporting air channel is provided with a flame outlet. A third main fire mixing zone is arranged in front of the flame outlet. A third main fire combustion zone is arranged in front of the third main fire mixing zone. The rear end of the outer housing is provided with a total gas inlet;

[0006] A mixing combustion cup is arranged in the combustion-supporting air passage. The mixing combustion cup is provided with a first vortex combustion zone chamber and a second vortex combustion zone chamber that are sequentially communicated from the rear to the front. A first vortex mixing zone is arranged at the rear side of the first vortex combustion zone chamber, and a second vortex mixing zone is arranged at the rear side of the second vortex combustion zone chamber. A gas inlet and a plurality of through first-stage combustion-supporting air diversion holes are arranged at the rear end of the first vortex combustion zone chamber. The gas inlet is communicated with the total gas inlet. The side wall of the first vortex combustion zone chamber gradually inclines towards the axis of the first vortex combustion zone chamber from the rear to the front. An opening is arranged at the front end of the second vortex combustion zone chamber. A plurality of through second-stage combustion-supporting air diversion holes and a first third-stage combustion-supporting air diversion hole are arranged on the side wall of the second vortex combustion zone chamber. A second third-stage combustion-supporting air diversion hole is arranged between the outer side wall of the mixing combustion cup and the burner pipe;

[0007] A gas spray head covers the gas inlet. The gas spray head is provided with a first gas diversion hole, a second gas diversion hole and a third gas diversion hole. The first gas diversion hole penetrates along the radial direction of the gas spray head. The front end of the second gas diversion hole faces the inner front side wall of the first vortex combustion zone chamber and advances into the second vortex mixing zone under the push of the air flow in the first vortex combustion zone. The third gas diversion hole penetrates along the front-rear direction and enters the third main fire mixing zone along the central axis of the combustion cup.

[0008] The low-nitrogen burner according to the embodiments of the present invention has at least the following beneficial effects: The fuel gas flows from the fuel gas inlet to the first fuel gas diversion hole, the second fuel gas diversion hole, and the third fuel gas diversion hole of the fuel gas nozzle. The first part of the fuel gas flows from the first fuel gas diversion hole of the fuel gas nozzle to the first vortex mixing zone, and the first part of the combustion-supporting air flows from the first-stage combustion-supporting air diversion hole to the first vortex mixing zone. Then, the first part of the fuel gas and the first part of the combustion-supporting air are mixed in the first vortex mixing zone and flow to the first vortex combustion zone chamber, where the first part of the fuel gas undergoes incomplete combustion. The second part of the fuel gas flows from the second fuel gas diversion hole of the fuel gas nozzle to the second vortex mixing zone, and the second part of the combustion-supporting air flows from the second-stage combustion-supporting air diversion hole to the second vortex mixing zone. Then, the second part of the fuel gas and the second part of the combustion-supporting air are mixed in the second vortex mixing zone and flow to the second vortex combustion zone chamber, where the second part of the fuel gas undergoes incomplete combustion. Of course, the incomplete combustion mixed gas generated from the first vortex combustion zone also participates in the mixing and combustion in the second-stage combustion chamber. The third part of the fuel gas flows from the third fuel gas diversion hole of the fuel gas nozzle to the third main fire mixing zone, and the third part of the combustion-supporting air flows from the first third-stage combustion-supporting air diversion hole and the second third-stage combustion-supporting air diversion hole to the third main fire mixing zone. The third part of the fuel gas and the third part of the combustion-supporting air are mixed in the third main fire mixing zone and flow to the third main fire combustion zone, where the third part of the fuel gas and the third part of the combustion-supporting air are fully burned, and the combustible gas that is not fully burned in the first vortex combustion zone chamber and the second vortex combustion zone chamber is also fully burned here.

[0009] The present invention is structurally divided into three-stage combustion. The first-stage vortex combustion zone is a combustion ring surrounding the fuel gas nozzle. Due to the physical structure here, a self-circulating air flow vortex will surely be generated here, and the combustion will be very stable after ignition. While burning a small part of the fuel gas, this combustion zone plays the role of heating the internal fuel gas and the external combustion-supporting air, igniting, and stabilizing the second and third-stage combustion. The middle channel is the main fuel gas transmission area, and most of the fuel gas is sent into the third main fire mixing zone from here. The main fuel gas in the central part of the second vortex combustion zone chamber is preheated and mixed while moving forward, and sequentially enters the third main fire mixing zone and the third main fire combustion zone. In the third main fire combustion zone, the fuel is fully burned, and the furnace temperature will also increase, even exceeding 1300 degrees. However, due to the precise ratio in the early stage and the three-stage proportional combustion, the fuel gas and the combustion-supporting air have been fully mixed and completely burned. Even when reaching the high-temperature conditions for nitrogen oxidation, due to the lack of oxygen, it is naturally impossible to re-oxidize nitrogen. In short, by improving the burner structure and using the principle of aerodynamics, the combustion process is carried out in stages, avoiding the situation where the local temperature exceeds 1300 degrees due to uneven mixing resulting in local concentrated combustion. Due to the precise staged ratio, it also avoids the presence of a large amount of oxygen in the area where the temperature exceeds 1300 degrees, thereby preventing the oxidation of nitrogen and greatly reducing or avoiding the generation of thermal-type nitrogen oxides.

[0010] In the first vortex mixing zone, the second vortex mixing zone, and the third main fire mixing zone, turbulence is formed due to the impact of various hot airflows in different directions. The turbulence enables the fuel gas and the combustion-supporting air to achieve a relatively uniform mixture before entering the third main fire mixing zone. After remixing in the third main fire mixing zone, the combustion in the third main fire combustion zone reaches a flameless combustion state. The third main fire mixing zone is a fully combusted area with the highest flame temperature among the three combustion zones. However, due to the lack of oxygen, nitrogen still cannot be oxidized. The combustion-supporting air and the fuel gas supplied to the first vortex combustion zone chamber and the second vortex combustion zone chamber are restricted, and they are in an incomplete combustion state with a low flame temperature. Therefore, the three-stage combustion structure of this burner ensures that the first two stages cannot burn fully, the flame temperature is low, and the conditions for nitrogen oxidation are not met. Although the flameless combustion flame temperature in the third stage is high, the mixing is sufficient and the air-fuel ratio is precise. It preferentially enables the fuel to burn fully, consumes all the oxygen, and makes nitrogen still unable to be oxidized under the conditions of high temperature and lack of oxygen, thereby realizing the process of low-nitrogen combustion.

[0011] In this three-stage combustion, the first and second stages of combustion are vortex ring-type mixing combustion. The existence of the vortex not only ensures the stability of the flame but also heats the fuel gas inside and the combustion-supporting air outside simultaneously with the heat generated by the first and second annular combustion layers, enabling the third-stage combustion to be carried out on the premise that the fuel gas and the air are preheated and premixed simultaneously. At the same time, in this combustion area, turbulence is formed due to the impact of various hot airflows in different directions. The turbulence makes the mixing more uniform and the combustion more complete, which is also the so-called flameless combustion. Therefore, the three-stage combustion structure of this burner ensures the process of low-nitrogen combustion.

[0012] According to some embodiments of the present invention, the diameter of the second vortex combustion zone chamber is greater than the diameter of the front end of the first vortex combustion zone chamber.

[0013] According to some embodiments of the present invention, a chamfer is provided between the side wall and the front wall of the second vortex combustion zone chamber.

[0014] According to some embodiments of the present invention, the axis of the second-stage combustion-supporting air diversion hole gradually inclines towards the axis of the second vortex combustion zone chamber from the back to the front.

[0015] According to some embodiments of the present invention, the combustion-supporting air of the third-stage combustion-supporting air diversion hole two gradually flows from the back to the front through the combustion-supporting air passage between the outside of the first vortex combustion zone chamber, the outside of the second vortex combustion zone chamber, and the burner tube to reach the third main fire mixing zone. The airflow directions of the first and second third-stage combustion-supporting air diversion holes gradually incline towards the axis of the third mixing combustion chamber.

[0016] According to some embodiments of the present invention, the opening area of the first gas diversion hole and the opening area of the second gas diversion hole are not greater than the opening area of the third gas diversion hole.

[0017] According to some embodiments of the present invention, the low-nitrogen burner further includes:

[0018] A gas pipe disposed in the combustion-supporting air passage. The mixing combustion cup is connected to the gas pipe. A gas outlet is provided at the front end of the gas pipe, and the gas outlet communicates with the total gas inlet.

[0019] According to some embodiments of the present invention, a concave cavity is provided at the rear side of the gas spray head, and the concave cavity communicates with the gas inlet.

[0020] According to some embodiments of the present invention, the low-nitrogen burner further includes:

[0021] A flame probe extends from the outer rear side of the first swirl combustion zone chamber to the outer rear side of the second swirl combustion zone chamber.

[0022] According to some embodiments of the present invention, the low-nitrogen burner further includes:

[0023] An ignition electrode extends into the rear end of the first swirl mixing zone of the first swirl combustion zone chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a cross-sectional schematic view of a low-nitrogen burner according to an embodiment of the present invention;

[0025] Figure 2 is a cross-sectional schematic view of a mixing combustion cup in an embodiment of the present invention;

[0026] Figure 3 is a front view schematic view of a low-nitrogen burner according to an embodiment of the present invention;

[0027] Figure 4 is a distribution schematic view of multiple combustion zones according to an embodiment of the present invention.

[0028] Reference numerals: outer housing 100, burner tube 101, combustion air passage 110, combustion air inlet 111, flame outlet 112, total gas inlet 113, mixing combustion cup 200, first vortex mixing zone 201, second vortex mixing zone 202, third main fire mixing zone 203, first vortex combustion zone chamber 220, gas inlet 221, first-stage combustion air diversion holes 222, second vortex combustion zone chamber 230, opening 231, second-stage combustion air diversion holes 232, first third-stage combustion air diversion holes 233, second third-stage combustion air diversion holes 240, chamfer 234, gas nozzle 300, first gas diversion holes 310, second gas diversion holes 320, third gas diversion holes 330, concave cavity 340, gas pipe 400, gas outlet 410, flame probe 500, ignition electrode 600. Detailed implementation manners

[0029] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0030] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by terms such as front, rear, upper, lower, axial direction, circumferential direction, etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

[0031] In the description of the present invention, the meaning of "a plurality" is two or more. Understandings such as "greater than", "less than", and "exceeding" do not include the present number, and understandings such as "above", "below", and "within" include the present number. If described as first and second, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0032] In the description of the present invention, it should be noted that terms such as "set", "installed", and "connected" should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0033] The technical solutions of the present invention will be described clearly and completely below with reference to the drawings. Obviously, the following described embodiments are some, but not all, embodiments of the present invention.

[0034] Referring to Figures 1 to 4 As shown, the following embodiments are made for the low-nitrogen burner of the embodiment of the present invention.

[0035] The low-nitrogen burner includes a housing 100, a burner tube 101, a mixing combustion cup 200, a gas nozzle 300, a gas pipe 400, a flame probe 500, and an ignition electrode 600.

[0036] The burner tube 101 is installed at the front end of the housing 100. After the housing 100 and the burner tube 101 are combined, a combustion-supporting air passage 110 is formed and arranged in the front-rear direction. A combustion-supporting air inlet 111 is provided on the side wall of the combustion-supporting air passage 110. The combustion-supporting air inlet 111 conveys combustion-supporting air into the combustion-supporting air passage 110. A flame outlet 112 communicating with the outside is provided at the front end of the combustion-supporting air passage 110.

[0037] The gas pipe 400 is arranged in the combustion-supporting air passage 110, and a gas outlet 410 is provided at the front end of the gas pipe 400.

[0038] A gas total inlet 113 is provided at the rear side of the housing 100, and the gas total inlet 113 is communicated with the gas pipe 400.

[0039] The mixing combustion cup 200 is installed in the combustion-supporting air passage 110 of the burner tube 101. A space is left between the outer side wall of the mixing combustion cup 200 and the inner side wall of the combustion-supporting air passage 110. A third-stage combustion-supporting air diversion hole two 240 is formed between the outer side wall of the mixing combustion cup 200 and the inner side wall of the combustion-supporting air passage 110.

[0040] A first vortex combustion zone chamber 220 and a second vortex combustion zone chamber 230 are arranged inside the mixing combustion cup 200. The front side of the first vortex combustion zone chamber 220 is communicated with the rear side of the second vortex combustion zone chamber 230. A gas inlet 221 penetrating through from front to back is provided in the middle of the rear side wall of the first vortex combustion zone chamber 220. A first vortex mixing zone 201 is provided at the rear side of the first vortex combustion zone chamber 220. A second vortex mixing zone 202 is provided at the rear side of the second vortex combustion zone chamber 230. The gas inlet 221 is installed on the gas outlet 410 of the gas pipe 400, so that the mixing combustion cup 200 is fixed inside the combustion-supporting air passage 110, and the gas pipe 400 injects gas into the gas inlet 221.

[0041] A third main fire mixing zone 203 is provided in front of the flame outlet 112 of the housing 100, and a third main fire combustion zone 250 is provided in front of the third main fire mixing zone 203.

[0042] The side wall of the first vortex combustion zone chamber 220 gradually inclines towards the axis of the mixing combustion cup 200 from back to front.

[0043] The gas nozzle 300 is arranged at the gas inlet 221. The gas nozzle 300 extends into the first vortex combustion zone chamber 220. A concave cavity 340 is arranged inside the gas nozzle 300. The gas nozzle 300 is provided with a plurality of first gas diversion holes 310, a plurality of second gas diversion holes 320 and a third gas diversion hole 330. The first gas diversion holes 310 penetrate through the gas nozzle 300 in the radial direction. The outlet of the second gas diversion holes 320 faces the inclined side wall of the first vortex combustion zone chamber 220. The third gas diversion hole 330 is located in the middle of the gas nozzle 300 and penetrates through in the front-back direction.

[0044] A plurality of first-stage combustion-supporting air diversion holes 222 that penetrate through in the front-back direction are further arranged on the rear side wall of the first vortex combustion zone chamber 220. The plurality of first-stage combustion-supporting air diversion holes 222 are evenly spaced along the outer periphery of the gas inlet 221. Each first-stage combustion-supporting air diversion hole 222 communicates with the combustion-supporting air channel 110.

[0045] An opening 231 is provided at the front end of the second vortex combustion zone chamber 230. A plurality of second-stage combustion-supporting air diversion holes 232 and a plurality of first third-stage combustion-supporting air diversion holes 233 are arranged on the side wall of the second vortex combustion zone chamber 230. The second-stage combustion-supporting air diversion holes 232 are located behind the first third-stage combustion-supporting air diversion holes 233. The axis of each second-stage combustion-supporting air diversion hole 232 gradually inclines towards the axis of the mixing combustion cup 200 from the back to the front. The axis of each first third-stage combustion-supporting air diversion hole 233 gradually inclines towards the axis of the mixing combustion cup 200 from the back to the front.

[0046] The fuel gas flows from the fuel gas inlet 221 to the first fuel gas flow guide hole 310, the second fuel gas flow guide hole 320 and the third fuel gas flow guide hole 330 of the fuel gas nozzle 300. A first portion of the fuel gas flows from the first fuel gas flow guide hole 310 of the fuel gas nozzle 300 to the first vortex mixing zone 201, and a first portion of the combustion-supporting air flows from the first-stage combustion-supporting air flow guide hole 222 to the first vortex mixing zone 201. Then, the first portion of the fuel gas and the first portion of the combustion-supporting air are mixed in the first vortex mixing zone 201 and flow to the first vortex combustion zone chamber 220, where the first portion of the fuel gas undergoes oxygen-deficient combustion. A second portion of the fuel gas flows from the second fuel gas flow guide hole 320 of the fuel gas nozzle 300 to the second vortex mixing zone 202, and a second portion of the combustion-supporting air flows from the second-stage combustion-supporting air flow guide hole 232 to the second vortex mixing zone 202. Then, the second portion of the fuel gas, the second portion of the combustion-supporting air, and the mixture gas after oxygen-deficient combustion in the first vortex combustion zone chamber 220 are mixed in the second vortex mixing zone 202 and flow to the second vortex combustion zone chamber 230, where oxygen-deficient combustion is achieved. A third portion of the fuel gas flows from the third fuel gas flow guide hole 330 of the fuel gas nozzle 300 to the third main fire mixing zone 203, and a third portion of the combustion-supporting air flows from the first third-stage combustion-supporting air flow guide hole 233 and the second third-stage combustion-supporting air flow guide hole 240 to the third main fire mixing zone 203. The third portion of the fuel gas, the third portion of the combustion-supporting air, and the remaining combustible components in the mixture gas generated by the first- and second-stage vortex-type oxygen-deficient combustion are fully mixed again in the third main fire mixing zone 203 and then flow to the third main fire combustion zone 250, where the third portion of the fuel gas, the third portion of the combustion-supporting air, and the remaining combustible components from the first- and second-stage vortex-type oxygen-deficient combustion are completely combusted. In the third main fire combustion zone 250, the oxygen in the air and the fuel gas injected at three levels are fully combusted. Theoretically, there is no excess fuel gas or excess oxygen.

[0047] The first vortex mixing zone 201 is a combustion ring surrounding the fuel gas nozzle 300. Due to the physical structure here, a self-circulating air flow vortex will be generated here, and the combustion will be very stable after ignition. While burning a small portion of the fuel gas, this annular combustion zone plays a role in heating the internal fuel gas and the external combustion-supporting air, igniting, and stabilizing the second- and third-stage combustion.

[0048] In the middle of the first swirling combustion zone chamber 220 is the main gas delivery area. Most of the gas is sent from here into the interior of the combustion ring of the second swirling combustion zone chamber 230 and the third main fire mixing zone 203. In the second swirling combustion zone chamber 230, a part of the gas is mixed to form an annular second swirling mixing zone 202. The central part of the annular second swirling combustion zone chamber 230 is the main gas delivery preheating area. The gas in the central part of the annular second swirling combustion zone chamber 230 preheats and mixes while moving forward, enters the third main fire mixing zone 203, and then enters the third main fire combustion zone 250 through the third main fire mixing zone 203. The fuel entering the third main fire combustion zone 250 burns fully, the combustion-supporting air is completely consumed, and the flame temperature will also increase significantly, even exceeding 1300 degrees. However, due to the precise ratio in the early stage and three-stage proportional combustion, the gas and the combustion-supporting air have achieved complete combustion. Even when reaching the high-temperature conditions for nitrogen oxidation, due to the oxygen-deficient environment, nitrogen cannot be re-oxidized naturally. By improving the burner structure and using the principle of aerodynamics, the combustion process is carried out in stages, avoiding the situation where the temperature exceeds 1300 degrees caused by concentrated combustion, preventing the oxidation of nitrogen, and greatly reducing the generation of thermal-type nitrogen oxides.

[0049] For this three-stage combustion, the first swirling mixing zone 201, the first swirling combustion zone chamber 220, the second swirling mixing zone 202, and the second swirling combustion zone chamber 230 are in a swirling mixing combustion mode. The existence of this swirl not only ensures the stability of the flame but also generates heat in the first swirling mixing zone 201, the first swirling combustion zone chamber 220, the second swirling mixing zone 202, and the second swirling combustion zone chamber 230, while preheating the internal gas and the external combustion-supporting air. As a result, the third main fire mixing zone 203 operates under the premise that both the gas and the combustion-supporting air are preheated and premixed. At the same time, in the third main fire mixing zone 203, turbulence is formed due to the impact of various hot airflows in different directions. The turbulence makes the mixing more uniform and the combustion more complete, which is the so-called flameless combustion. Therefore, the three-stage combustion structure of this burner ensures the low-nitrogen combustion process.

[0050] This embodiment is divided into three - stage combustion structurally. The first vortex mixing zone 201 is a combustion ring surrounding the gas nozzle 300. Due to the physical structure here, a self - circulating air flow vortex will be generated here. After ignition, the combustion will be very stable. While burning a small part of the gas in this combustion zone, it plays the role of heating the internal gas and external combustion - supporting air, igniting and stabilizing the second - vortex combustion and the third - main - fire combustion. In the middle of the first - vortex combustion zone chamber 220 is the main gas delivery area. Most of the gas is sent into the interior of the combustion ring of the second - vortex combustion zone chamber 230 from here. At the rear end of the second - vortex combustion zone chamber 230 is the second - vortex mixing zone 202. The central part of the annular second - vortex combustion zone chamber 230 is the main gas delivery pre - heating area. The gas in the central part of the annular second - vortex combustion zone chamber 230 is pre - heated and moves forward, entering the third - main - fire mixing zone 203. In the third - main - fire mixing zone 203, the fuel is fully mixed. In the third - main - fire combustion zone 250, all combustible gases and combustion - supporting air are fully burned, the flame temperature will increase significantly, and the furnace temperature will also increase, even exceeding 1300 degrees. However, due to the precise proportioning in the early stage and the three - stage proportional combustion, the gas and combustion - supporting air have achieved complete combustion. Even when reaching the high - temperature conditions for nitrogen oxidation, due to the oxygen - deficient environment, it is naturally impossible to re - oxidize nitrogen. By improving the burner structure and using the principle of aerodynamics, the combustion process is carried out in stages, avoiding the situation where the local temperature exceeds 1300 degrees caused by local concentrated combustion, preventing the oxidation of nitrogen, and greatly reducing the generation of thermal - type nitrogen oxides. In this three - stage combustion, the first - vortex mixing zone 201, the first - vortex combustion zone chamber 220, the second - vortex mixing zone 202, and the second - vortex combustion zone chamber 230 are vortex - type mixing combustion. The existence of this vortex not only ensures the stability of the flame but also generates heat in the first - vortex mixing zone 201, the first - vortex combustion zone chamber 220, the second - vortex mixing zone 202, and the second - vortex combustion zone chamber 230, while pre - heating the internal gas and external combustion - supporting air, so that the third - main - fire mixing zone 203 is carried out on the premise that the gas and combustion - supporting air are pre - heated and pre - mixed at the same time. Inside the third - main - fire mixing zone 203, turbulence is formed due to the impact of various hot air flows in different directions. The turbulence makes the mixing more uniform and the combustion more complete, that is, the so - called flameless combustion. Therefore, the three - stage combustion structure of this burner ensures the process of low - nitrogen combustion.

[0051] Flameless combustion is a special combustion method. In this combustion, the fuel and air are pre - mixed evenly, the combustion speed is fast, the temperature distribution in the reaction area is relatively uniform, the flame surface is not obvious, and even the flame cannot be seen. Compared with traditional flame combustion, flameless combustion has the advantages of high combustion efficiency and low pollutant nitrogen oxide emissions.

[0052] The third - main - fire mixing zone 203 can be regarded as flameless combustion. Characteristics of flameless combustion technology:

[0053] Premixing: The fuel and air start to mix before entering the third main combustion mixing zone 203, forming a relatively uniform combustible mixture, then entering the third main combustion mixing zone 203 for secondary mixing. After sufficient mixing, it enters the third main combustion zone 250 to complete sufficient combustion - flameless combustion.

[0054] High turbulence: Due to the impact of airflows in different directions in the first vortex mixing zone 201, the first vortex combustion zone chamber 220, the second vortex mixing zone 202, and the second vortex combustion zone chamber 230, turbulence is formed. During the premixing process in the third main combustion mixing zone 203, a relatively high turbulence intensity is maintained, which efficiently promotes the full mixing of the main gas, the remaining combustible gas, and the oxygen in the air, and a full combustion reaction occurs at the third main combustion zone 250.

[0055] High temperature: The third main combustion zone 250 maintains a relatively high temperature to ensure a rapid combustion reaction.

[0056] No obvious flame front: Due to the uniform mixing, the combustion reaction occurs simultaneously throughout the entire area of the third main combustion zone 250, so there will be no obvious flame front.

[0057] This low-nitrogen burner mainly utilizes the vortex characteristics, turbulence characteristics of aerodynamics, and a structural design conducive to fluid mixing to achieve staged mixing and combustion, control the flame temperature and combustion speed, avoid the generation of thermal-type nitrogen oxides due to overall or local high temperatures during the combustion process, and achieve low-nitrogen combustion.

[0058] The principle of aerodynamic vortex is embodied in three aspects here:

[0059] Promote mixing: Vortices or eddies can fully mix the fuel and air before combustion, avoid the formation of local high-temperature regions caused by combustion, and thus inhibit the generation of nitrogen oxides. In this embodiment, a multi-stage vortex structure design is adopted to achieve staged mixing combustion management and avoid overheating in centralized mixing combustion. In this embodiment, the first and second stages of oxygen-deficient combustion avoid the temperature exceeding 1300 degrees.

[0060] Uniform distribution: The vortices or eddies are set in stages, and the combustion process in the multi-stage eddy ring region is more uniform, avoiding local concentrated combustion of the fuel and reducing nitrogen oxide emissions.

[0061] Prolong the mixing and combustion residence time of the combustion-supporting air and gas: The appropriately-intensified staged vortex structure set can prolong the circulation residence time of the combustion products, promote the reduction reaction of nitrogen oxides, and further reduce the nitrogen oxide content.

[0062] In some embodiments, as shown in reference to Figure 2 the diameter of the front end of the first vortex combustion zone chamber 220 is smaller than the diameter of the second vortex combustion zone chamber 230.

[0063] A step is formed between the front end of the first swirling combustion zone chamber 220 and the rear end of the second swirling combustion zone chamber 230. The unburned combustible gas injected from the first swirling combustion zone chamber 220 into the second swirling combustion zone chamber 230 flows towards the side wall of the second swirling combustion zone chamber 230 due to the enlarged flow area, thereby causing the mixed gas to form a second eddy current at the rear end of the second swirling combustion zone chamber 230. The secondary combustion-supporting air guiding holes 232 on the side wall of the second swirling combustion zone chamber 230 inject combustion-supporting air, which is mixed with the gas and ignited, forming a second swirling mixing zone 202 at the rear side of the second swirling combustion zone chamber 230, contributing to the formation of a stable annular incomplete combustion in the second swirling combustion zone chamber 230 and facilitating the ignition of the tertiary main fire combustion in front of the ignition opening 231.

[0064] In some embodiments, referring to Figure 2 As shown, a chamfer 234 is provided between the inner side wall and the front side inner wall of the second swirling combustion zone chamber 230.

[0065] This helps the gas and combustion-supporting air in the second swirling combustion zone chamber 230 to blow towards the ignition opening 231 along the chamfer 234, contributing to the formation of a stable and continuous mixed gas of gas and combustion-supporting air in front of the ignition opening 231, enabling the stable and complete combustion of the gas and combustion-supporting air.

[0066] In some embodiments, the secondary combustion-supporting air guiding holes 232 gradually incline towards the central axis of the mixing combustion cup 200 from the rear to the front, the tertiary combustion-supporting air guiding holes one 233 gradually incline towards the central axis of the mixing combustion cup 200 from the rear to the front, and the tertiary combustion-supporting air guiding holes two 240 gradually incline towards the central axis of the mixing combustion cup 200 from the rear to the front.

[0067] Combustion-supporting air is blown from the rear to the front between the outer side wall of the mixing combustion cup 200 and the inner side wall of the burner tube 101. When the combustion-supporting air flows through the secondary combustion-supporting air guiding holes 232, the tertiary combustion-supporting air guiding holes one 233, and the tertiary combustion-supporting air guiding holes two 240 on the side wall of the second swirling combustion zone chamber 230, the combustion-supporting air can be sprayed into the second swirling mixing zone 202 along the axial direction of the secondary combustion-supporting air guiding holes 232 to mix with the corresponding gas, and achieve annular combustion in the second swirling combustion zone chamber 230, while pushing the mixed gas flow to continue flowing towards the tertiary main fire mixing zone 203. The combustion-supporting air can be sprayed into the tertiary main fire mixing zone 203 along the axial direction of the tertiary combustion-supporting air guiding holes one 233, where it meets the preheated gas sent by the tertiary gas guiding holes 330 and the unburned combustible gas that has not been fully burned in the first and second swirling combustion zones, undergoes full mixing, and then proceeds into the tertiary main fire combustion zone 250 to achieve full combustion.

[0068] In some embodiments, referring to Figures 2 to 4As shown, a plurality of second-stage combustion air guide holes two 240 are provided on the outer side wall of the hybrid combustion cup 200. Each second-stage combustion air guide hole two 240 gradually inclines towards the axis of the third main fire mixing zone 203 from the rear to the front, and is sprayed into the third main fire mixing zone 203. The combustion air sprayed through the first-stage combustion air guide holes one 233 is mixed with the combustion air in the third main fire mixing zone 203 and burns sufficiently in the third main fire combustion zone 250.

[0069] In some embodiments, referring to Figure 2 As shown, the diameter of the second gas guide hole 320 is smaller than that of the third gas guide hole 330, and the diameter of the first gas guide hole 310 is smaller than that of the third gas guide hole 330.

[0070] It is ensured that the amount of gas flowing out of the third gas guide hole 330 is more than that flowing out of the second gas guide hole 320 and the first gas guide hole 310, so that a small amount of gas forms a first eddy current at the rear side of the first vortex combustion zone chamber 220, that is, a first vortex mixing zone 201 is formed; a small amount of unburned gas enters the rear side of the second vortex combustion zone chamber 230 along the inclined side wall of the first vortex combustion zone chamber 220 and forms a second eddy current with the gas sprayed through the second gas guide hole 320, that is, a second vortex mixing zone 202 is formed. Most of the gas flows towards the third main fire mixing zone 203 along the inside of the first vortex combustion zone chamber 220, the inside of the second vortex combustion zone chamber 230, and the middle position of the opening 231, that is, meets and mixes with the combustion air sprayed through the first-stage and second-stage combustion air guide holes in front of the flame outlet 112, forming the third main fire mixing zone 203.

[0071] In some embodiments, referring to Figure 1 With Figure 2 As shown, the low-nitrogen burner further includes a gas pipe 400. The gas pipe 400 is arranged in the combustion air passage 110, and the front end of the gas pipe 400 is connected to the hybrid combustion cup 200. A through gas outlet 410 is provided at the front end of the gas pipe 400, and the gas inlet 221 is communicated with the gas outlet 410.

[0072] The hybrid combustion cup 200 is fixed by using the gas pipe 400, which facilitates the assembly of the gas pipe 400 and the hybrid combustion cup 200.

[0073] In some embodiments, referring to Figure 2 As shown, a concave cavity 340 is provided on the rear inner side of the gas spray head 300, and the concave cavity 340 covers the gas inlet 221.

[0074] The concave cavity 340 is used to obstruct the gas injected into the gas inlet 221, ensuring that the gas can be injected into the first gas diversion hole 310, the third gas diversion hole 330, and the second gas diversion hole 320 for flow according to the design requirements. The areas of the gas diversion holes are strictly calculated and precisely processed, so that the gas volume ejected from each diversion hole meets the requirements of the corresponding combustion area, thereby avoiding all the gas being concentrated and injected into one or two gas diversion holes.

[0075] In some embodiments, referring to Figure 2 as shown, the low-nitrogen burner further includes a flame probe 500. The flame probe 500 extends forward from the rear outer side of the first vortex combustion zone chamber 220 to the rear outer side of the second vortex combustion zone chamber 230, and the end of the flame probe 500 is located directly in front of the third gas diversion hole 330 of the first gas diversion hole.

[0076] The flame probe 500 is used to monitor the combustion condition in the first vortex combustion zone chamber 220. In this embodiment, the flame probe 500 is used to monitor the combustion condition in the first vortex combustion zone, so as to accurately obtain the ignition situation inside the mixing combustion cup 200.

[0077] In some embodiments, referring to Figure 2 as shown, the low-nitrogen burner further includes an ignition electrode 600. The ignition electrode 600 extends into the rear side of the first vortex combustion zone chamber 220.

[0078] The ignition electrode 600 discharges and ignites from the rear side of the first vortex mixing zone 201, which helps to ignite the mixture in the first vortex mixing zone 201 in the first time and ensure the stable combustion of the first vortex combustion zone chamber 220.

[0079] The embodiments of the present invention have been described in detail above with reference to the drawings. However, the present invention is not limited to the above embodiments. Within the knowledge of those of ordinary skill in the art to which the present invention pertains, various changes can be made without departing from the gist of the present invention, and these changes also fall within the scope of technical protection.

Claims

1. A low-nitrogen burner, characterized in that, Comprising: An outer housing provided with a combustion-supporting air passage. The combustion-supporting air passage is provided with a combustion-supporting air inlet. The front end of the combustion-supporting air passage is provided with a flame outlet. A third main fire mixing zone is arranged in front of the flame outlet. A third main fire combustion zone is arranged in front of the third main fire mixing zone. The rear end of the outer housing is provided with a total gas inlet. A mixing combustion cup is arranged in the combustion-supporting air passage. The mixing combustion cup is provided with a first vortex combustion zone chamber and a second vortex combustion zone chamber that are connected in sequence from back to front. A first vortex mixing zone is arranged at the rear side of the first vortex combustion zone chamber. A second vortex mixing zone is arranged at the rear side of the second vortex combustion zone chamber. The rear end of the first vortex combustion zone chamber is provided with a gas inlet and a plurality of through first-stage combustion-supporting air guiding holes. The gas inlet is communicated with the total gas inlet. The side wall of the first vortex combustion zone chamber gradually inclines towards the axis of the first vortex combustion zone chamber from back to front. The front end of the second vortex combustion zone chamber is provided with an opening. The side wall of the second vortex combustion zone chamber is provided with a plurality of through second-stage combustion-supporting air guiding holes and a first third-stage combustion-supporting air guiding hole. A second third-stage combustion-supporting air guiding hole is arranged between the outer side wall of the mixing combustion cup and the combustion-supporting air passage. A gas spray head covers the gas inlet. The gas spray head is provided with a first gas guiding hole, a second gas guiding hole and a third gas guiding hole. The first gas guiding hole penetrates along the radial direction of the gas spray head. The front end of the second gas guiding hole faces the inner side wall of the first vortex combustion zone chamber. The third gas guiding hole penetrates along the front-back direction. A concave cavity is arranged at the rear side of the gas spray head. The concave cavity is communicated with the gas inlet. A gas pipe is arranged in the combustion-supporting air passage. The mixing combustion cup is connected to the gas pipe. The front end of the gas pipe is provided with a gas outlet. The gas outlet is communicated with the total gas inlet. A flame probe extends from the outer rear side of the first vortex combustion zone chamber into the outer rear side of the second vortex combustion zone chamber. An ignition electrode extends into the rear side of the first vortex combustion zone chamber.

2. The low-nitrogen burner according to claim 1, characterized in that, The diameter of the second vortex combustion zone chamber is larger than the diameter of the front end of the first vortex combustion zone chamber.

3. The low-nitrogen burner according to claim 1, characterized in that, A chamfer is arranged between the side wall and the front wall of the second vortex combustion zone chamber.

4. The low-nitrogen burner according to claim 1, characterized in that, The axis of the second-stage combustion-supporting air guiding hole gradually inclines towards the axis of the second vortex combustion zone chamber from back to front.

5. The low-nitrogen burner according to claim 1, characterized in that, The second third-stage combustion-supporting air guiding hole gradually inclines towards the axis of the mixing combustion cup from back to front.

6. The low-nitrogen burner according to claim 1, wherein The conduction area of the first gas guiding hole and the conduction area of the second gas guiding hole are not larger than the conduction area of the third gas guiding hole.

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