Low-nitrogen burner

Abstract

The invention discloses a low-nitrogen burner, which belongs to the technical field of kiln burners and is characterized in that turbulent flow is formed in a first vortex mixing area and a second vortex mixing area due to impact of various hot air flows in different directions, and combustible gas and combustion-supporting air are premixed by the turbulent flow; the combustion air and the fuel gas are fully mixed in the third main fire mixing area and enter the third main fire combustion area, so that the combustion reaches a flameless combustion state, the third main fire combustion area is a full combustion area with the highest flame temperature in the three combustion areas, but the combustion air and the fuel gas supplied by the first-stage combustion area and the second-stage combustion area are limited, so that the combustion effect is greatly improved. In an incomplete combustion state, the flame temperature is low, it is guaranteed that the first two stages cannot be fully combusted, the flame temperature is low, and the condition of generating nitric oxide is not met, although the flame temperature of the third stage is high, mixing is sufficient, the air-fuel ratio is accurate, fuel is preferentially fully combusted, all oxygen is consumed, nitrogen still cannot be oxidized under the high-temperature and oxygen-deficient conditions, and the combustion efficiency is improved. And therefore, the low-nitrogen combustion process is realized.

Description

Technical Field

[0001] The 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 the products in the kiln or to ignite the kiln. Existing conventional burners generally have only one-stage mixing. The combustion air is mixed with the gas and then ignited. Due to the uneven mixing, local high temperature will occur after ignition, which will easily cause nitrogen and oxygen to react to form nitrogen oxides, such as air pollutants such as nitric oxide and nitrogen dioxide. Since there is only one-stage mixing, unevenness is likely to occur, which will lead to the formation of thermal nitrogen oxides, or even exceed the standard. This requires strict control of the burner diversion and grading combustion process starting from the burner structure design, so as 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. To this end, the present invention proposes a burner for achieving low nitrogen combustion. The design concept is to change the one-stage mixed combustion of the conventional burner into a 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 levels, each level has a corresponding combustion zone, the first vortex mixing zone and the second vortex mixing zone are both vortex annular mixed combustion zones, the vortex is determined by the physical structure of the burner, and its existence not only ensures the stability of the flame, but also releases heat due to combustion in the first annular combustion zone and the second annular combustion zone. This heat heats the gas inside the annular combustion zone and the combustion-supporting air outside at the same time, so that the third main fire mixing zone is carried out under the premise that the gas and the combustion-supporting air are preheated and premixed at the same time. At the same time, turbulence is formed in the first and second annular combustion zones due to the collision of multiple airflows in different directions. The turbulence makes the mixing more uniform and the combustion more complete, which promotes 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 of the third main fire combustion zone, so the three-stage combustion structure of the burner ensures the low-nitrogen combustion process.

[0004] A low nitrogen burner according to an embodiment of the present invention comprises: The outer shell is 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, the front of the flame outlet is provided with a third main fire mixing zone, the front of the third main fire mixing zone is provided with a third main fire combustion zone, and the rear end of the outer shell 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 which are connected in sequence from back to front, a first vortex mixing zone is provided at the rear side of the first vortex combustion zone chamber, a second vortex mixing zone is provided at the rear side of the second vortex combustion zone chamber, a gas inlet and a plurality of first-stage combustion air guide holes which are connected in a rear end of the first vortex combustion zone chamber, the gas inlet is connected with the total gas inlet, a side wall of the first vortex combustion zone chamber is gradually inclined toward the axis of the first vortex combustion zone chamber from back to front, an opening is provided at the front end of the second vortex combustion zone chamber, a plurality of second-stage combustion air guide holes which are connected in a side wall of the second vortex combustion zone chamber and a third-stage combustion air guide hole 1 which are connected in a rear end of the mixing combustion cup and the burner tube; A gas nozzle, a cover is arranged on the gas inlet, and the gas nozzle is provided with a first gas guide hole, a second gas guide hole and a third gas guide hole. The first gas guide hole penetrates along the radial direction of the gas nozzle, the front end of the second gas guide hole faces the inner front side wall of the first vortex combustion zone chamber, and moves forward into the second vortex mixing zone under the push of the airflow in the first vortex combustion zone. The third gas guide hole penetrates along the front-to-back direction and enters the third main fire mixing zone along the central axis of the combustion cup.

[0005] The low nitrogen burner according to the embodiment of the present invention has at least the following beneficial effects: the gas flows from the gas inlet to the first gas guide hole, the second gas guide hole and the third gas guide hole of the gas nozzle, the first part of the gas flows from the first gas guide hole of the gas nozzle to the first vortex mixing zone, the first part of the combustion-supporting air flows from the first-stage combustion-supporting air guide hole to the first vortex mixing zone, then the first part of the 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, and incomplete combustion of the first part of the gas is achieved in the first vortex combustion zone chamber; the second part of the gas flows from the second gas guide hole of the 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 guide hole to the second vortex mixing zone, then the second part of the gas and the second part of the combustion-supporting air are mixed in the first vortex mixing zone and flow to the first vortex combustion zone chamber. After mixing in the vortex mixing zone, it flows to the second vortex combustion zone chamber, and incomplete combustion of the second part of the gas is realized in the second vortex combustion zone chamber. Of course, the incompletely burned mixed gas generated in the first vortex combustion zone will also participate in the mixing and combustion in the second combustion chamber; the third part of the gas flows from the third gas guide hole of the gas nozzle to the third main fire mixing zone, and the third part of the combustion air flows from the third-level combustion air guide hole one and the third-level combustion air guide hole two to the third main fire mixing zone. After the third part of the gas and the third part of the combustion air are mixed in the third main fire mixing zone, they flow to the third main fire combustion zone. The third main fire combustion zone fully burns the third part of the gas and the third part of the combustion air, 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.

[0006] The present invention is structurally divided into three stages of combustion. The first stage vortex combustion zone is a combustion ring surrounding the gas nozzle. Due to the physical structure here, a self-circulating airflow vortex will be generated here, and the combustion will be very stable after ignition. This combustion zone burns a small part of the gas while heating the internal gas and external combustion-supporting air, igniting and stabilizing the second and third stage combustion. The middle channel is the main gas delivery area, and most of the gas is sent to the third main fire mixing area from there. The main gas in the center of the second vortex combustion area chamber is preheated and mixed while moving forward, and enters the third main fire mixing area and the third main fire combustion area in turn. In the third main fire combustion area, the fuel is fully burned, and the furnace temperature will rise, even exceeding 1300 degrees. However, due to the precise proportioning in the early stage and the three-stage proportional combustion, the gas and the combustion-supporting air have been fully mixed and completely burned. Even if the high temperature conditions for nitrogen oxidation are reached, the nitrogen cannot be reoxidized due to lack of oxygen. In short, by improving the burner structure and utilizing the principles of aerodynamics, the combustion process is carried out in stages, avoiding the situation where the local temperature exceeds 1300 degrees due to uneven mixing and local concentrated combustion. Due to the precise proportioning, the presence of a large amount of oxygen in the area where the temperature exceeds 1300 degrees is avoided, thereby preventing the oxidation of nitrogen and greatly reducing or avoiding the formation of thermal nitrogen oxides.

[0007] In the first vortex mixing zone, the second vortex mixing zone and the third main fire mixing zone, turbulence is formed due to the collision of multiple hot air flows in different directions. The turbulence makes the gas and the combustion-supporting air reach 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 the fully burned area with the highest flame temperature among the three combustion zones. However, due to lack of oxygen, nitrogen still cannot be oxidized. The combustion-supporting air and gas supplied by the first vortex combustion zone chamber and the second vortex combustion zone chamber are restricted, which is in an incomplete combustion state and the flame temperature is low. Therefore, the three-stage combustion structure of the burner ensures that the first two stages cannot be fully burned, the flame temperature is low, and there is no condition for nitrogen oxidation. Although the flame temperature of the third stage flameless combustion is high, the mixing is sufficient and the air-fuel ratio is accurate. It gives priority to fully burning the fuel and consumes all the oxygen, so that the nitrogen cannot be oxidized under the condition of high temperature and lack of oxygen, thereby realizing the process of low nitrogen combustion.

[0008] In this three-stage combustion, the first and second stages of combustion are vortex annular mixed combustion. The existence of the vortex not only ensures the stability of the flame, but also uses the heat generated by the first and second annular combustion layers to heat the internal gas and external combustion air at the same time, so that the third stage of combustion is carried out under the premise that the gas and air are preheated and premixed at the same time. At the same time, turbulence is formed in the combustion area due to the collision of multiple hot air flows in different directions. The turbulence makes the mixing more uniform and the combustion more complete. This is also often called flameless combustion. Therefore, the three-stage combustion structure of the burner ensures the low-nitrogen combustion process.

[0009] According to some embodiments of the present invention, the diameter of the second swirl combustion zone chamber is greater than the diameter of the front end of the first swirl combustion zone chamber.

[0010] 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.

[0011] According to some embodiments of the present invention, the axis of the second-stage combustion-supporting air guide hole gradually inclines from back to front toward the axis of the second vortex combustion zone chamber.

[0012] According to some embodiments of the present invention, the combustion air of the third-stage combustion air guide hole two gradually flows from back to front through the combustion air channels outside the first vortex combustion zone chamber, outside the second vortex combustion zone chamber and between the burner tube to reach the third main fire mixing zone, and the airflow directions of the third-stage combustion air guide hole one and the third-stage combustion air guide hole two gradually incline toward the axis of the third mixing combustion chamber.

[0013] According to some embodiments of the present invention, a conduction area of ​​the first gas flow guide hole and a conduction area of ​​the second gas flow guide hole are not greater than a conduction area of ​​the third gas flow guide hole.

[0014] According to some embodiments of the present invention, the low nitrogen burner further comprises: A gas pipe is arranged in the combustion-supporting air channel, the mixing combustion cup is connected to the gas pipe, a gas outlet is arranged at the front end of the gas pipe, and the gas outlet is connected to the main gas inlet. According to some embodiments of the present invention, a cavity is provided on the rear side of the gas nozzle, and the cavity is connected to the gas inlet.

[0015] According to some embodiments of the present invention, the low nitrogen burner further comprises: The flame probe extends from the rear outer side of the first vortex combustion zone chamber into the rear outer side of the second vortex combustion zone chamber.

[0016] According to some embodiments of the present invention, the low nitrogen burner further comprises: An ignition electrode extends into the rear end of the first vortex mixing zone of the first vortex combustion zone chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a cross-sectional schematic diagram of a low nitrogen burner according to an embodiment of the present invention; Figure 2 is a cross-sectional schematic diagram of a mixing combustion cup in one embodiment of the present invention; Figure 3 is a front view schematic diagram of a low nitrogen burner according to an embodiment of the present invention; Figure 4 It is a schematic diagram of the distribution of multiple combustion zones according to an embodiment of the present invention.

[0018] Figure markings: outer shell 100, burner tube 101, combustion air channel 110, combustion air inlet 111, flame outlet 112, total gas air inlet 113, mixed 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 guide hole 222, second vortex combustion zone chamber 230, opening 231, second stage combustion air guide hole 232, third stage combustion air guide hole one 233, third stage combustion air guide hole two 240, chamfer 234, gas nozzle 300, first gas guide hole 310, second gas guide hole 320, third gas guide hole 330, concave cavity 340, gas pipe 400, gas outlet 410, flame probe 500, ignition electrode 600. DETAILED DESCRIPTION

[0019] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0020] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by terms such as front, rear, top, bottom, axial, and circumferential are based on the orientations or positional relationships shown in the accompanying 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 cannot be understood as a limitation on the present invention.

[0021] In the description of the present invention, the meaning of "above", "below", "exceed", etc. is not inclusive of the number itself, and the meaning of "above", "below", "within", etc. is inclusive of the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0022] In the description of the present invention, it should be noted that the terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0023] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described below are only some embodiments of the present invention, not all embodiments.

[0024] Reference Figures 1 to 4 As shown, the low nitrogen burner of the embodiment of the present invention is made into the following embodiment.

[0025] The low nitrogen burner comprises an outer shell 100 , a burner tube 101 , a mixing combustion cup 200 , a gas nozzle 300 , a gas tube 400 , a flame probe 500 and an ignition electrode 600 .

[0026] The burner tube 101 is installed at the front end of the outer shell 100. The outer shell 100 and the burner tube 101 are combined to form a combustion air channel 110 arranged along the front-to-back direction. The side wall of the combustion air channel 110 is provided with a combustion air inlet 111. The combustion air inlet 111 transports combustion air into the combustion air channel 110. The front end of the combustion air channel 110 is provided with a flame outlet 112 connected to the outside world.

[0027] The gas pipe 400 is disposed in the combustion-supporting air passage 110 , and a gas outlet 410 is disposed at the front end of the gas pipe 400 .

[0028] A main gas inlet 113 is provided at the rear side of the outer shell 100 , and the main gas inlet 113 is communicated with the gas pipe 400 .

[0029] The mixing combustion cup 200 is installed in the combustion air channel 110 of the burner tube 101, and a space is left between the outer wall of the mixing combustion cup 200 and the inner wall of the combustion air channel 110. A third-level combustion air guide hole 240 is formed between the outer wall of the mixing combustion cup 200 and the inner wall of the combustion air channel 110.

[0030] A first vortex combustion zone chamber 220 and a second vortex combustion zone chamber 230 are provided inside the mixing combustion cup 200. The front side of the first vortex combustion zone chamber 220 is connected to the rear side of the second vortex combustion zone chamber 230. A gas inlet 221 that passes through the front and rear 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 on the rear side of the first vortex combustion zone chamber 220, and a second vortex mixing zone 202 is provided on 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 channel 110, and the gas pipe 400 sprays gas into the gas inlet 221.

[0031] A third main fire mixing zone 203 is arranged in front of the flame outlet 112 of the outer shell 100 , and a third main fire burning zone 250 is arranged in front of the third main fire mixing zone 203 .

[0032] The side wall of the first vortex combustion zone chamber 220 gradually inclines toward the axis of the mixing combustion cup 200 from the back to the front.

[0033] The gas nozzle 300 is arranged at the gas inlet 221, and 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 guide holes 310, a plurality of second gas guide holes 320, and a third gas guide hole 330. The first gas guide hole 310 penetrates along the radial direction of the gas nozzle 300, the second gas guide hole 320 faces the inclined side wall outlet of the first vortex combustion zone chamber 220, and the third gas guide hole 330 is located in the middle of the gas nozzle 300, and the third gas guide hole 330 penetrates along the front-back direction.

[0034] The rear side wall of the first vortex combustion zone chamber 220 is also provided with a plurality of first-stage combustion air guide holes 222 that pass through the first stage, and the plurality of first-stage combustion air guide holes 222 are evenly spaced along the periphery of the gas inlet 221 , and each first-stage combustion air guide hole 222 is connected to the combustion air channel 110 .

[0035] An opening 231 is provided at the front end of the second vortex combustion zone chamber 230, and a plurality of second-stage combustion-supporting air guide holes 232 and a plurality of third-stage combustion-supporting air guide holes 233 are provided on the side walls of the second vortex combustion zone chamber 230. The second-stage combustion-supporting air guide holes 232 are located behind the third-stage combustion-supporting air guide holes 233, and the axis of each second-stage combustion-supporting air guide hole 232 gradually inclines toward the axis of the mixed combustion cup 200 from back to front, and the axis of each third-stage combustion-supporting air guide hole 233 gradually inclines toward the axis of the mixed combustion cup 200 from back to front.

[0036] The gas flows from the gas inlet 221 to the first gas guide hole 310, the second gas guide hole 320 and the third gas guide hole 330 of the gas nozzle 300, the first part of the gas flows from the first gas guide hole 310 of the gas nozzle 300 to the first vortex mixing zone 201, and the first part of the combustion-supporting air flows from the first-stage combustion-supporting air guide hole 222 to the first vortex mixing zone 201, then the first part of the gas and the first part of the combustion-supporting air are mixed in the first vortex mixing zone 201 and flow to the first vortex combustion zone chamber 220, and the first part of the gas is burned in the first vortex combustion zone chamber 220 in the absence of oxygen; the second part of the gas flows from the second gas guide hole 320 of the gas nozzle 300 to the second vortex mixing zone 202, and the second part of the combustion-supporting air flows from the second-stage combustion-supporting air guide hole 232 to the second vortex mixing zone 202, then the second part of the gas, the second part of the combustion-supporting air and the mixed gas after the oxygen-deficient combustion of the first vortex combustion zone chamber 220 are burned in the second vortex combustion zone chamber 220. The third part of the gas flows from the third gas guide hole 330 of the gas nozzle 300 to the third main fire mixing zone 203, and the third part of the combustion-supporting air flows from the third-stage combustion-supporting air guide hole 1 233 and the third-stage combustion-supporting air guide hole 2 240 to the third main fire mixing zone 203. The third part of the gas, the third part of the combustion-supporting air and the remaining combustible components in the mixed gas produced by the first and second stage vortex oxygen-deficient combustion are fully mixed again in the third main fire mixing zone 203 and flow to the third main fire combustion zone 250. The third part of the gas, the third part of the combustion-supporting air and the remaining combustible components in the first and second stage vortex oxygen-deficient combustion are completely burned in the third main fire combustion zone 250. In the third main fire combustion zone 250, the oxygen in the air and the gas injected in the third stage are fully burned. In theory, there is no excess gas and no excess oxygen.

[0037] The first vortex mixing zone 201 is a combustion ring surrounding the gas nozzle 300. Due to the physical structure here, a self-circulating airflow vortex will be generated here, and the combustion will be very stable after ignition. While burning a small part of the gas, this annular combustion zone heats the internal gas and external combustion air, ignites and stabilizes the second and third stage combustion.

[0038] The middle of the first vortex combustion zone chamber 220 is the main gas delivery zone, from which most of the gas is delivered to the interior of the combustion ring of the second vortex combustion zone chamber 230 and the third main fire mixing zone 203. Part of the gas is mixed in the second vortex combustion zone chamber 230 to form an annular second vortex mixing zone 202. The central part of the annular second vortex combustion zone chamber 230 is the main gas delivery preheating zone. The gas in the central part of the annular second vortex combustion zone chamber 230 moves forward while being preheated and mixed, 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 is fully burned, the combustion air is also completely consumed, and the flame temperature will also increase significantly, even exceeding 1300 degrees. However, due to the precise proportioning in the early stage and the three-stage proportional combustion, the gas and the combustion air have been completely burned. Even if the high temperature conditions for nitrogen oxidation are reached, the nitrogen cannot be reoxidized due to the lack of oxygen in the environment. By improving the burner structure and utilizing aerodynamic principles, the combustion process is carried out in stages, avoiding the temperature exceeding 1300 degrees caused by concentrated combustion, preventing the oxidation of nitrogen, and greatly reducing the generation of thermal nitrogen oxides.

[0039] 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 mixed combustion. The existence of the 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, and preheats the internal gas and the external combustion air at the same time, so that the third main fire mixing zone 203 is carried out under the premise that the gas and the combustion air are preheated and premixed at the same time. At the same time, turbulence is formed in the third main fire mixing zone 203 due to the collision of multiple hot air flows in different directions. The turbulence makes the mixing more uniform and the combustion more complete, which is often called flameless combustion. Therefore, the three-stage combustion structure of the burner ensures the low-nitrogen combustion process.

[0040] This embodiment is structurally divided into three stages of combustion. The first vortex mixing zone 201 is a combustion ring surrounding the gas nozzle 300. Due to the physical structure here, a self-circulating airflow vortex will be generated here. After ignition, the combustion will be very stable. This combustion zone burns a small part of the gas and heats the internal gas and external combustion air, ignites and stabilizes the second vortex combustion and the third main fire combustion. The middle of the first vortex combustion zone chamber 220 is the main gas delivery zone, and most of the gas is sent to the interior of the combustion ring of the second vortex combustion zone chamber 230. 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 preheating zone. The gas in the central part of the annular second vortex combustion zone chamber 230 moves forward while being preheated, and enters 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, and the flame temperature will also 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 been completely burned. Even if the high temperature condition for nitrogen oxidation is reached, the nitrogen cannot be reoxidized due to the lack of oxygen. 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 local concentrated combustion, preventing the oxidation of nitrogen, and greatly reducing the generation of thermal nitrogen oxides. 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 mixed combustion. The existence of the vortex not only ensures the stability of the flame, but also enables 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 to generate heat, and at the same time preheats the internal gas and the external combustion air, so that the third main fire mixing zone 203 is carried out under the premise that the gas and the combustion air are preheated and premixed at the same time. Inside the third main fire mixing zone 203, turbulence is formed due to the collision of multiple hot air flows in different directions. The turbulence makes the mixing more uniform and the combustion more complete, which is often called flameless combustion. Therefore, the three-stage combustion structure of the burner ensures the low-nitrogen combustion process.

[0041] 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 emission of pollutants such as nitrogen oxides.

[0042] The third main fire mixing zone 203 can be regarded as flameless combustion. Characteristics of flameless combustion technology: Premixing: The fuel and air have already started to mix before entering the third main fire mixing zone 203 to form a relatively uniform combustible mixture, and then enter the third main fire mixing zone 203 for secondary mixing. After being fully mixed, they enter the third main fire combustion zone 250 to complete full combustion - flameless combustion.

[0043] 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. In the premixing process of the third main fire mixing zone 203, a high turbulence intensity is maintained, which effectively promotes the full mixing of the main fuel gas, the remaining combustible gas and the oxygen in the air, and a full combustion reaction occurs in the third main fire combustion zone 250.

[0044] High temperature: The third main fire combustion zone 250 maintains a relatively high temperature to ensure a rapid combustion reaction.

[0045] No obvious flame front: Due to the uniform mixing, the combustion reaction takes place simultaneously in the entire area of ​​the third main fire combustion zone 250, so there will be no obvious flame front.

[0046] This low-nitrogen burner mainly utilizes the aerodynamic vortex characteristics, turbulence characteristics and a structural design that is conducive to fluid mixing to achieve graded mixing and combustion, control the flame temperature and combustion speed, avoid the generation of thermal nitrogen oxides due to overall or local high temperatures during the combustion process, and achieve low-nitrogen combustion.

[0047] The aerodynamic vortex principle is reflected in three aspects here: Promote mixing: Swirls or eddies can fully mix fuel and air before combustion, avoiding the formation of local high-temperature areas caused by combustion, thereby inhibiting the generation of nitrogen oxides. This embodiment adopts a multi-stage vortex structure design to achieve graded mixed combustion management and avoid overheating of concentrated mixed combustion. In this embodiment, the first and second stages of oxygen-deficient combustion avoid temperatures exceeding 1300 degrees.

[0048] Uniform distribution: The vortex or eddy current is set in stages, and the combustion process in the multi-stage vortex ring area is more uniform, avoiding localized concentrated combustion of fuel and reducing nitrogen oxide emissions.

[0049] Prolong the mixing and combustion residence time of combustion air and gas: A graded vortex structure with appropriate intensity can prolong the circulation residence time of combustion products, promote the reduction reaction of nitrogen oxides, and further reduce the nitrogen oxide content.

[0050] In some embodiments, reference Figure 2 As shown, the diameter of the front end of the first swirl combustion zone chamber 220 is smaller than the diameter of the second swirl combustion zone chamber 230 .

[0051] A step is formed between the front end of the first vortex combustion zone chamber 220 and the rear end of the second vortex combustion zone chamber 230. The unburned combustible gas sprayed from the first vortex combustion zone chamber 220 into the second vortex combustion zone chamber 230 flows toward the side wall of the second vortex combustion zone chamber 230 due to the expansion of the flow area, thereby causing the mixed gas to form a second vortex at the rear end of the second vortex combustion zone chamber 230. The second-stage combustion air guide hole 232 on the side wall of the second vortex combustion zone chamber 230 sprays combustion air to mix with the gas and ignite it, forming a second vortex mixing zone 202 on the rear side of the second vortex combustion zone chamber 230, which helps to form a stable annular incomplete combustion in the second vortex combustion zone chamber 230, and helps to ignite the third-stage main fire combustion in front of the opening 231.

[0052] In some embodiments, reference Figure 2 As shown, a chamfer 234 is provided between the inner wall and the front inner wall of the second swirl combustion zone chamber 230 .

[0053] It helps the gas and combustion-supporting air in the second vortex combustion zone chamber 230 to blow toward the opening 231 along the chamfer 234, and helps to form a stable and continuous gas mixture of gas and combustion-supporting air in front of the opening 231, so that the gas and combustion-supporting air can burn stably and fully.

[0054] In some embodiments, the second-stage combustion-supporting air guide hole 232 gradually inclines toward the central axis of the mixing combustion cup 200 from back to front, the third-stage combustion-supporting air guide hole 1 233 gradually inclines toward the central axis of the mixing combustion cup 200 from back to front, and the third-stage combustion-supporting air guide hole 240 gradually inclines toward the central axis of the mixing combustion cup 200 from back to front.

[0055] Combustion-supporting air is blown from the back to the front between the outer wall of the mixing combustion cup 200 and the inner wall of the burner tube 101. When the combustion-supporting air flows through the second-stage combustion-supporting air guide hole 232, the third-stage combustion-supporting air guide hole 1 233, and the third-stage combustion-supporting air guide hole 2 240 on the side wall of the second vortex combustion zone chamber 230, the combustion-supporting air can be sprayed into the second vortex mixing zone 202 along the axial direction of the second-stage combustion-supporting air guide hole 232 so as to mix with the corresponding gas and realize annular combustion in the second vortex combustion zone chamber 230, while pushing the mixed gas flow to continue to flow to the third main fire mixing zone 203. The combustion-supporting air can be sprayed into the third main fire mixing zone 203 along the axial direction of the third-stage combustion-supporting air guide hole 1 233, where it encounters the preheated gas sent from the third gas guide hole 330 and the combustible gas that is not fully burned in the first and second vortex combustion zones, and is fully mixed, and then moves forward into the third main fire combustion zone 250 to realize full combustion.

[0056] In some embodiments, reference Figures 2 to 4As shown, a plurality of third-stage combustion-supporting air guide holes 240 are arranged on the outer wall of the mixing combustion cup 200. Each third-stage combustion-supporting air guide hole 240 is gradually inclined from back to front toward the axis of the third main fire mixing zone 203, and is sprayed into the third main fire mixing zone 203, and is fully mixed with the combustion air sprayed into the third-stage combustion-supporting air guide hole 1 233 in the third main fire mixing zone 203 and is fully burned in the third main fire combustion zone 250.

[0057] In some embodiments, reference Figure 2 As shown, the diameter of the second gas flow guiding hole 320 is smaller than the diameter of the third gas flow guiding hole 330 , and the diameter of the first gas flow guiding hole 310 is smaller than the diameter of the third gas flow guiding hole 330 .

[0058] Ensure that the amount of gas flowing out of the third gas guide hole 330 is greater than the amount of gas flowing out of the second gas guide hole 320 and the amount of gas flowing out of the first gas guide hole 310, so that a small amount of gas forms a first vortex on the rear side of the first vortex combustion zone chamber 220, that is, forms a first vortex mixing zone 201; 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 together with the gas injected into the second gas guide hole 320 to form a second vortex, that is, forms a second vortex mixing zone 202, and most of the gas flows along the interior of the first vortex combustion zone chamber 220, the interior of the second vortex combustion zone chamber 230, and the middle position of the opening 231 to the third main fire mixing zone 203, that is, meets and mixes with the combustion air injected through the third-stage combustion air guide holes one and two in front of the flame outlet 112 to form the third main fire mixing zone 203.

[0059] In some embodiments, reference Figure 1 and Figure 2 As shown, the low nitrogen burner is also provided with a gas pipe 400, which is arranged in the combustion-supporting air channel 110, and the front end of the gas pipe 400 is connected to the mixing combustion cup 200. A through gas outlet 410 is arranged at the front end of the gas pipe 400, and the gas inlet 221 is connected to the gas outlet 410.

[0060] The gas pipe 400 is used to fix the mixing combustion cup 200, so that the gas pipe 400 and the mixing combustion cup 200 can be easily assembled.

[0061] In some embodiments, reference Figure 2 As shown, a concave cavity 340 is disposed on the rear inner side of the gas nozzle 300 , and the concave cavity 340 covers the gas inlet 221 .

[0062] The concave cavity 340 is used to block the gas injected into the gas inlet 221, ensuring that the gas can be injected into the first gas guide hole 310, the third gas guide hole 330 and the second gas guide hole 320 according to the design requirements. The area of ​​the gas guide hole is strictly calculated and accurately processed so that the amount of gas injected from each guide hole meets the needs of the corresponding combustion area, thereby avoiding all the gas from being concentratedly injected into one or two gas guide holes.

[0063] In some embodiments, reference Figure 2 As shown, the low nitrogen burner is also provided with a flame probe 500, which 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 first gas guide hole and the third gas guide hole 330.

[0064] The flame probe 500 is used to monitor the combustion conditions in the first vortex combustion zone chamber 220 . In this embodiment, the flame probe 500 is used to monitor the combustion conditions in the first vortex combustion zone so as to accurately obtain the ignition conditions inside the mixed combustion cup 200 .

[0065] In some embodiments, reference Figure 2 As shown, the low nitrogen burner is also provided with an ignition electrode 600 , and the ignition electrode 600 extends into the rear side of the first vortex combustion zone chamber 220 .

[0066] The ignition electrode 600 discharges and ignites from the rear side of the first vortex mixing zone 201 , which helps to ignite the mixed gas in the first vortex mixing zone 201 at the first time, ensuring stable combustion of the first vortex combustion zone chamber 220 .

[0067] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention, and these changes belong to the scope of technical protection.

Claims

1. A low nitrogen burner, characterized in that: include: The outer shell is 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, the front of the flame outlet is provided with a third main fire mixing zone, the front of the third main fire mixing zone is provided with a third main fire combustion zone, and the rear end of the outer shell 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 which are connected in sequence from back to front, a first vortex mixing zone is provided at the rear side of the first vortex combustion zone chamber, a second vortex mixing zone is provided at the rear side of the second vortex combustion zone chamber, a gas inlet and a plurality of first-stage combustion air guide holes which are connected in a rear end of the first vortex combustion zone chamber, the gas inlet is connected with the total gas air inlet, a side wall of the first vortex combustion zone chamber is gradually inclined toward the axis of the first vortex combustion zone chamber from back to front, an opening is provided at the front end of the second vortex combustion zone chamber, a plurality of second-stage combustion air guide holes which are connected in a side wall of the second vortex combustion zone chamber and a third-stage combustion air guide hole 1 which are connected in a rear end of the mixing combustion cup and the combustion-supporting air passage; A gas nozzle cover is arranged on the gas inlet, and the gas nozzle is provided with a first gas guide hole, a second gas guide hole and a third gas guide hole. The first gas guide hole penetrates along the radial direction of the gas nozzle, the front end of the second gas guide hole faces the inner wall of the first vortex combustion zone chamber, and the third gas guide hole penetrates along the front-to-back direction.

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

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

5. The low nitrogen burner according to claim 1, characterized in that: The third-stage combustion-supporting air guide hole 2 is gradually inclined from the back to the front toward the axis of the mixed combustion cup.

6. The low nitrogen burner according to claim 1, characterized in that: The conduction area of ​​the first gas guide hole and the conduction area of ​​the second gas guide hole are not greater than the conduction area of ​​the third gas guide hole.

7. The low nitrogen burner according to claim 1, characterized in that: The low nitrogen burner also includes: A gas pipe is arranged in the combustion-supporting air channel, the mixing combustion cup is connected to the gas pipe, a gas outlet is arranged at the front end of the gas pipe, and the gas outlet is connected to the main gas inlet.

8. The low nitrogen burner according to claim 1, characterized in that: A concave cavity is provided on the rear side of the gas nozzle, and the concave cavity is connected to the gas inlet.

9. The low nitrogen burner according to claim 1, characterized in that: The low nitrogen burner also includes: The flame probe extends from the rear outer side of the first vortex combustion zone chamber into the rear outer side of the second vortex combustion zone chamber.

10. The low nitrogen burner according to claim 1, characterized in that: The low nitrogen burner also includes: An ignition electrode extends into the rear side of the first vortex combustion zone chamber.

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