A performance-adaptive low-NOx burner

Abstract

This invention relates to the field of burner technology and discloses a performance-adaptive low-NOx burner. The burner includes an air intake section and an intake annular cavity. A gas intake pipe is connected to the outer wall of the intake annular cavity; a central gas vertical connecting section is connected to the inner wall of the intake annular cavity; a central gas main pipe is connected to the tail end of the central gas vertical connecting section; an air separator is fitted over the central gas main pipe; several radial premixed nozzles are evenly distributed along the central gas main pipe near the inlet of the air separator; several support rods are evenly distributed along the middle of the central gas main pipe; multiple peripheral gas branch pipes are evenly arranged on the side wall of the intake annular cavity; an air pipe, an air pipe contraction cone section, an air ejector contraction section, and an air ejector mixing pipe are sequentially arranged at the tail end of the intake annular cavity; the burner includes an ejector flue gas volume adjustment mechanism. This invention can adjust the ejector flue gas volume in a timely manner according to changes in nitrogen oxides, making the burner operation more stable and producing lower NOx levels.

Description

Technical Field

[0001] This invention belongs to the field of burner technology, specifically relating to a performance-adaptive low-NOx burner. Background Technology

[0002] In low-NOx technologies for gas-fired low-NOx burners, premixed combustion poses risks of backfire and explosion, is difficult to control, and is not energy-efficient enough. External flue gas recirculation also presents challenges such as flame instability and increased costs, hindering the long-term stable operation of the furnace. Therefore, staged combustion and internal flue gas recirculation are more reasonable technical approaches.

[0003] There are many existing methods for achieving flue gas recirculation, such as secondary air accelerated jet, air swirl to entrain flue gas, and the use of ejector principles, where the ejection of both fuel gas and air allows for flue gas recirculation, resulting in lower nitrogen oxide emissions. For example, the low-NOx in-furnace recirculation gas burner with authorization notice number CN 211694876U uses dual ejection of fuel gas and air, which can reduce NOx emissions by recirculating a large amount of flue gas. However, such a structure also has limitations; it cannot autonomously adjust to changes in NOx emissions caused by external environmental factors such as changes in combustion air intake, fuel gas pressure, and fuel type. Therefore, the design of a low-NOx burner structure that can adapt to emissions and automatically adjust the amount of ejected flue gas is crucial for organizing combustion and reducing pollutant emissions. Summary of the Invention

[0004] The purpose of this invention is to provide a performance-adaptive low-NOx burner to solve the problem in the prior art where the internal recirculation structure of the ejector flue gas cannot be adjusted, and the nitrogen oxides cannot be adjusted according to changes in the combustion air intake, gas pressure, type, and other factors caused by changes in the external environment.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0006] A performance-adaptive low-NOx burner, the burner comprising an air intake section and an intake annular cavity:

[0007] The outer wall of the intake annular cavity is connected to a gas intake pipe; the inner wall of the intake annular cavity is connected to a central gas vertical connection section; the tail end of the central gas vertical connection section is connected to a central gas main pipe; an air separator cylinder is fitted over the central gas main pipe; several radial premixed nozzles are evenly distributed on the central gas main pipe near the inlet of the air separator cylinder; several support rods are evenly distributed in the middle of the central gas main pipe, and the other end of each support rod is fixedly connected to the air separator cylinder.

[0008] Multiple peripheral gas branch pipes are evenly arranged on the side wall of the air intake ring cavity; the tail of the air intake ring cavity is provided with an air pipe, an air pipe contraction cone section, an air ejector contraction section and an air ejector mixing pipe in sequence from the air intake section to the air separator cylinder.

[0009] The burner includes an ejector flue gas volume adjustment mechanism; the ejector flue gas volume adjustment mechanism is connected to the air pipe contraction cone section and the air ejector contraction section, and is used to adjust the relative position of the air pipe contraction cone section and the air ejector contraction section.

[0010] Furthermore, the ejector gas volume adjustment mechanism includes, from left to right, an adjustment servo, an adjustment servo shaft, a coupling, and a spiral structure. The spiral structure includes a spiral rod sleeve, an adjustment spiral rod, and a spiral rod threaded section. The adjustment spiral rod is partially sleeved within the spiral rod sleeve. The end of the adjustment spiral rod furthest from the adjustment servo is connected to the spiral rod threaded section. A spiral rod nut is coaxially sleeved on the spiral rod threaded section, forming a threaded connection structure. An axial tie rod is provided at the end of the spiral rod nut furthest from the adjustment spiral rod. One end of the axial tie rod is fixedly connected to the spiral rod nut, and the other end passes through the air pipe contraction cone section and is fixedly connected to the air ejector contraction section.

[0011] Furthermore, the air tube contraction cone section is connected to the air tube, and the air tube contraction cone section and the air tube form an interior angle, the interior angle being 90-180°; the air ejector contraction section is connected to the air ejector mixing tube; the air tube contraction cone section and the air ejector contraction section are arranged in parallel and have a certain interval.

[0012] Furthermore, a flame stabilizing plate is installed at the downstream end of the central gas main pipe, and a number of radial nozzles and radial spray pipes of the central gas main pipe are evenly distributed between the flame stabilizing plate and the central gas main pipe; the flame stabilizing plate air holes are evenly arranged between the radial spray pipes of the central gas main pipe.

[0013] Furthermore, the gas ventilation area of ​​the radial nozzle of the central main pipe accounts for 4% to 10% of the total gas outlet area.

[0014] Furthermore, the intake ring cavity is composed of an outer ring plate, an outer tube plate, an inner expansion plate, and an inner tube plate. The inner expansion plate is an expansion ramp, which is used to achieve smooth flow of combustion air when it enters the air pipe from the air intake section, thereby reducing pressure loss.

[0015] Furthermore, the peripheral gas branch pipe and the air ejector retraction section are clearance-fitted, which facilitates the axial movement of the air ejector retraction section and the air ejector mixing pipe along the air ejector mixing pipe.

[0016] Furthermore, the axial tie rod and the air tube contraction cone section are fitted with a clearance, which facilitates the axial movement of the axial tie rod along the axial direction of the air ejector mixing tube.

[0017] Furthermore, several ejector mixing tube support columns are evenly installed in the middle of the air ejector mixing tube; universal wheels are installed at the ends of the ejector mixing tube support columns; the universal wheels form a guiding contact with the outer wall of the air separator cylinder.

[0018] Furthermore, the burner also includes a nitrogen oxide sensor and a burner controller; both the adjustment servo and the nitrogen oxide sensor are connected to the burner controller.

[0019] Compared with existing technologies, the beneficial effects of this invention are:

[0020] (1) Enhance the mixing of air and fuel gas to make the mixing more uniform, improve combustion efficiency, and increase boiler thermal efficiency;

[0021] (2) Forming air and fuel stages to form a multi-stage flame, reducing the flame temperature, thereby greatly reducing nitrogen oxide emissions;

[0022] (3) The emission of nitrogen oxides is further reduced by adopting flue gas internal circulation and partial premixed combustion technology.

[0023] (4) Adjust the flue gas internal circulation in a timely manner according to the changes in nitrogen oxides to make the burner operation more stable and low nitrogen. Attached Figure Description

[0024] The present invention can be further illustrated by the non-limiting embodiments given in the accompanying drawings;

[0025] Figure 1 This is a cross-sectional view of a low-NOx burner with automatic airflow adjustment according to the present invention;

[0026] Figure 2 This is a three-dimensional structural diagram of a low-NOx burner with automatic air volume adjustment according to the present invention;

[0027] Figure 3 This is a side view of a low-NOx burner with automatic airflow adjustment according to the present invention.

[0028] The symbols for the main components are explained below:

[0029] 1. Air intake section; 2. Gas intake pipe; 21. Outer ring plate of intake ring cavity; 22. Outer tube plate of intake ring cavity; 23. Inner expansion plate of intake ring cavity; 24. Inner tube plate of intake ring cavity; 25. Spiral rod sleeve; 3. Air separator cylinder; 31. Support rod;

[0030] Air pipe 4; Air pipe constriction cone section 41; Air ejector mixing pipe 5; Air ejector constriction section 51; Ejector mixing pipe support column 52; Caster wheel 53; Peripheral gas branch pipe 6; Central gas main pipe 7; Central gas vertical connection section 71; Main pipe radial premixed nozzle 72; Central gas main pipe end sealing plate 73; Central main pipe radial nozzle 75; Central main pipe radial nozzle 76.

[0031] Flame stabilizer 8; Flame stabilizer air hole 81; Adjustment servo 9; Adjustment servo shaft 91; Coupling 92; Burner controller 93; Adjustment screw rod 10; Screw rod threaded section 101; Screw rod nut 102; Axial tie rod 103. Detailed Implementation

[0032] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that similar or identical parts are referred to by the same reference numerals in the drawings or description. Implementations not shown or described in the drawings are forms known to those skilled in the art. In addition, directional terms mentioned in the embodiments, such as "up," "down," "top," "bottom," "left," "right," "front," and "back," are only for reference to the directions in the drawings and are not intended to limit the scope of protection of the present invention.

[0033] like Figure 1-3 As shown, a performance-adaptive low-NOx burner includes an air intake section 1 and an intake annular cavity:

[0034] The outer wall of the intake ring cavity is connected to a gas intake pipe 2; in some embodiments, the intake ring cavity is composed of an outer ring plate 21, an outer tube plate 22, an inner expansion plate 23, and an inner tube plate 24; specifically, the gas intake pipe 2 is connected to the outer tube plate 22 of the intake ring cavity, and thus communicates with the intake ring cavity, for inputting gas into the burner.

[0035] The inner wall of the intake annular cavity is connected to a central gas vertical connection section 71. Specifically, the central gas vertical connection section 71 is connected to the inner tube sheet 24 of the intake annular cavity, and thus to the intake annular cavity. The tail end of the central gas vertical connection section 71 is connected to a central gas main pipe 7. The end of the central gas main pipe 7 away from the central gas vertical connection section 71 is closed. In some embodiments, the central gas main pipe 7 is sealed by a central gas main pipe end sealing plate 73. The design of the central gas vertical connection section 71 and the central gas main pipe 7 allows gas to enter the burner from the center. Through this layout, the gas can be evenly distributed, thereby achieving a more uniform combustion process.

[0036] The central gas main pipe 7 is fitted with an air separator 3. Several radial premixed nozzles 72 are evenly distributed around the central gas main pipe 7 near the inlet of the air separator 3. By distributing multiple radial premixed nozzles 72 at the inlet of the central gas main pipe 7, multiple ignition sources can be provided, increasing combustion stability. This is crucial for preventing localized flameout and unstable combustion. It also ensures the uniformity of fuel entry into the combustion zone, helping to avoid the formation of excessive fuel or air in certain areas, thus improving combustion uniformity and stability.

[0037] Several support rods 31 are evenly distributed along the middle of the central gas main pipe 7, with the other end of each support rod 31 fixedly connected to the air separator cylinder 3. The support rods 31 provide structural support and stability. By connecting the central gas main pipe 7 and the air separator cylinder 3, the support rods 31 can withstand the forces and pressures between them, maintaining the stability of the entire burner structure, especially under high temperature and high pressure environments. This arrangement ensures the relative stability of the positions of the gas main pipe 7 and the air separator cylinder 3, which is crucial for maintaining the consistency of the gap, alignment, and relative position between the gas main pipe and the air separator cylinder, ensuring proper fuel-air mixing and combustion efficiency.

[0038] Multiple peripheral gas branch pipes 6 are evenly arranged on the sidewall of the intake annular cavity. At the tail end of the intake annular cavity, from the air intake section 1 to the air separator cylinder 3, an air pipe 4, an air pipe constriction cone section 41, an air ejector constriction section 51, and an air ejector mixing pipe 5 are sequentially arranged. Specifically, several peripheral gas branch pipes 6 are evenly installed on the inner expansion plate 23 of the intake annular cavity. One end of each peripheral gas branch pipe 6 is connected to the inner expansion plate 23 of the intake annular cavity, and the other end passes sequentially through the air pipe constriction cone section 41 and the air ejector constriction section 51, extending beyond the end of the air ejector mixing pipe 5 and located outside the air ejector mixing pipe 5. In some embodiments, the air intake section 1, air pipe 4, air pipe constriction cone section 41, air ejector constriction section 51, air ejector mixing pipe 5, central gas main pipe 7, and air separator cylinder 3 are all coaxially arranged. This coaxial arrangement optimizes the airflow path. Air enters the air pipe 4 from the air intake section 1, and gradually contracts through the air pipe constriction cone section 41 and the air ejector constriction section 51 before finally entering the air ejector mixing pipe 5. This coaxial arrangement helps to smoothly guide the airflow, reduce resistance and turbulence, improve the efficiency of airflow, and help to achieve uniform mixing of fuel gas and air, thereby improving combustion efficiency and combustion stability.

[0039] The burner includes an ejector flue gas volume regulating mechanism; this mechanism is connected to the air pipe contraction cone section 41 and the air ejector contraction section 51, and is used to adjust the relative positions of the air pipe contraction cone section 41 and the air ejector contraction section 51. This ejector flue gas volume regulating mechanism can be a burner nozzle design: by adjusting the structure and size of the burner nozzle, the degree of fuel-air mixing can be controlled, thereby affecting the ejector flue gas volume. For example, changing parameters such as nozzle orifice diameter, nozzle geometry, and outlet angle can adjust the fuel and air flow rate and injection velocity, thus affecting the ejector flue gas volume. It can also be an air conditioner: the air conditioner in the burner can be used to control the air supply and flow rate, thereby regulating the ejector flue gas volume. By adjusting the opening or position of the air conditioner, the air flow rate and velocity can be changed, thus affecting the ejector volume. Alternatively, it can be an ejector structure adjustment: the ejector structure in the burner can also be adjusted to control the ejector flue gas volume. By changing parameters such as the geometry and outlet area of ​​the ejector, the injection velocity and angle of the flue gas can be affected, thereby controlling the amount of ejected flue gas.

[0040] In some embodiments, the ejector gas volume adjustment mechanism includes, from left to right, an adjustment servo 9, an adjustment servo shaft 91, a coupling 92, and a spiral structure. The spiral structure includes a spiral rod sleeve 25, an adjustment spiral rod 10, and a spiral rod threaded section 101. The adjustment spiral rod 10 is partially sleeved within the spiral rod sleeve 25. Specifically, the spiral rod sleeve 25 is installed between the outer tube plate 22 and the inner tube plate 24 of the intake ring cavity. One end of the spiral rod sleeve 25 is installed on the outer ring plate 21 of the intake ring cavity, and the other end is installed on the inner expansion plate 23 of the intake ring cavity. The axis of the spiral rod sleeve 25 is parallel to the axis of the outer tube plate 22 of the intake ring cavity. The adjustment spiral rod 10... A spiral rod sleeve 25 extends through and out of both ends of the spiral rod sleeve 25; one end of the spiral rod sleeve 25 is sequentially connected to a coupling 92, an adjusting servo shaft 91, and an adjusting servo 9, and the other end has a spiral rod threaded section 101; the end of the adjusting spiral rod 10 away from the adjusting servo 9 is connected to the spiral rod threaded section 101; a spiral rod nut 102 is coaxially sleeved on the spiral rod threaded section 101, and the two form a threaded sleeve structure; an axial tie rod 103 is provided at the end of the spiral rod nut 102 away from the adjusting spiral rod 10; one end of the axial tie rod 103 is fixedly connected to the spiral rod nut 102, and the other end passes through the air pipe contraction cone section 41 and is fixedly connected to the air ejector contraction section 51.

[0041] The extension / retraction length of the adjusting screw rod 10 can be changed by adjusting the position of the screw rod nut 102. When the adjusting screw rod 10 extends or retracts outward, the screw rod nut 102 pushes the axial tie rod 103 outward, thereby changing the position of the air ejector retraction section 51. In this way, the ejection position and angle of the air ejector retraction section 51 can be adjusted, thereby controlling the amount of ejected flue gas. The extension / retraction length of the screw rod 10 can be quickly changed by rotating the screw rod nut 102, and the design of the axial tie rod 103 makes the adjustment process more convenient and stable.

[0042] In some embodiments, the diameter of the air ejector mixing tube 5 is larger than that of the air separator tube 3, and it is sleeved outside the air separator tube 3; the air tube contraction cone section 41 is connected to the air tube 4, and the air tube contraction cone section 41 and the air tube 4 form an internal angle, the internal angle being 90-180°; the air ejector contraction section 51 is connected to the air ejector mixing tube 5; the air tube contraction cone section 41 and the air ejector contraction section 51 are arranged in parallel and have a certain interval.

[0043] The arrangement of the air ejector contraction section 51 helps to create a stable air ejection environment. By paralleling the air pipe contraction cone section 41 and the air ejector contraction section 51, and the spacing between them, the ejection speed and direction of the air can be effectively controlled, resulting in a more uniform and stable mixture with the combustion gas, reducing the possibility of non-uniform combustion and flame instability. Furthermore, by precisely controlling the structure and spacing between the air pipe contraction cone section 41, the air ejector contraction section 51, and the air ejector mixing pipe 5, appropriate airflow dynamics and pressure distribution can be formed within the burner. This contributes to a more uniform combustion process, improves combustion efficiency and stability, and reduces the likelihood of generating harmful substances such as nitrogen oxides.

[0044] In some embodiments, a flame stabilizer 8 is installed at the downstream end of the central gas main pipe 7, and a plurality of central gas main pipe radial nozzles 75 and central gas main pipe radial nozzles 76 are evenly distributed between the flame stabilizer 8 and the central gas main pipe end sealing plate 73; the central gas main pipe radial nozzles 75 and central gas main pipe radial nozzles 76 are staggered; the central gas main pipe radial nozzles 76 are arranged close to the flame stabilizer 8; the flame stabilizer 8 has flame stabilizer 81 air holes 81 evenly arranged between the central gas main pipe radial nozzles 76; and a plurality of main pipe radial premixed nozzles 72 are evenly distributed near the inlet of the air separator cylinder 3 of the central gas main pipe 7.

[0045] The flame stabilizer 8 is located at the downstream end of the central gas main pipe 7, and the radial nozzles 75 of the central gas main pipe are evenly distributed between the flame stabilizer 8 and the end sealing plate 73 of the central gas main pipe. This arrangement can improve the stability of combustion and the controllability of the combustion process. The gas ejected from the radial nozzles 75 of the central gas main pipe interacts with the flame on the flame stabilizer 81 to form a stable flame cone, providing a stable combustion environment.

[0046] The uniformly arranged air holes on the flame stabilizer plate 81 are used to introduce external air. By adjusting the air flow rate and distribution, the mixing ratio of fuel gas and air during combustion can be affected, further regulating combustion stability and the formation of nitrogen oxides (NOx).

[0047] The central gas main pipe 7 has radial premixing nozzles 72 evenly distributed near the inlet of the air separator 3 for mixing gas and air. The premixing nozzles premix the gas and air to form a homogeneous gas / air mixture, thereby improving combustion efficiency and reducing emissions.

[0048] This configuration, together, achieves flame stability, gas injection control, and air regulation, further improving the combustion efficiency and stability of the low-NOx burner.

[0049] In some embodiments, the gas passage area of ​​the central main radial nozzle 75 accounts for 4% to 10% of the total gas outlet area. One of the design goals of low-NOx burners is to control the formation of nitrogen oxides (NOx). By adjusting the passage area of ​​the central main radial nozzle 75, the distribution and mixing of the gas can be optimized, thereby reducing the amount of NOx generated during combustion. Providing an appropriate amount of gas supply in the central region of the burner can improve combustion efficiency. By increasing the gas concentration and velocity, the completeness of the combustion process can be improved, allowing the fuel to burn more completely, thereby increasing combustion efficiency.

[0050] In some embodiments, the intake annular cavity is composed of an outer annular plate 21, an outer tube plate 22, an inner expansion plate 23, and an inner tube plate 24. The inner expansion plate 23 is an expanding ramp, used to achieve smooth flow of combustion air from the air intake section 1 into the air pipe 4, reducing pressure loss. The expanding ramp shape of the inner expansion plate 23 helps to achieve smooth flow of combustion air from the air intake section 1 into the air pipe 4. By providing a gradually widening channel, the expanding ramp reduces the velocity gradient and turbulence of the fluid, contributing to a more uniform and stable airflow. The design of the expanding ramp can reduce the pressure loss of combustion air flowing through the intake annular cavity. As the flow gradually slows down during expansion, the pressure gradient decreases, thereby reducing energy loss and fluid pressure loss. By reducing pressure loss and energy loss, the design of the inner expansion plate 23 of the intake annular cavity can improve the efficiency of the entire system. Lower pressure loss means that more combustion air can be effectively delivered to the burner, thereby promoting the combustion reaction and improving combustion efficiency.

[0051] In some embodiments, the peripheral gas branch pipe 6 and the air ejector retractable section 51 are clearance-fitted to facilitate axial movement of the air ejector retractable section 51 and the air ejector mixing pipe 5 along the axial direction of the air ejector mixing pipe 5. In some embodiments, the axial tie rod 103 and the air pipe retractable cone section 41 are clearance-fitted to facilitate axial movement of the axial tie rod 103 along the axial direction of the air ejector mixing pipe 5.

[0052] The position of the air ejector mixing tube 5 can be adjusted by allowing the air ejector retraction section 51 and the air ejector mixing tube 5 to move axially, and by allowing the axial tie rod 103 to move axially along the air ejector mixing tube 5, thereby changing the mixing ratio of fuel gas and air. Moving the air ejector mixing tube 5 can increase or decrease the degree of fuel gas-air mixing, thus affecting combustion stability, combustion efficiency, and emission generation. This can alter the flow field and turbulence structure during combustion, which is crucial for optimizing combustion characteristics such as combustion stability, heat load distribution, and nitrogen oxide (NOx) generation control.

[0053] In some embodiments, a plurality of ejector mixing tube support columns 52 are evenly installed at the middle position of the air ejector mixing tube 5; universal wheels 53 are installed at the ends of the ejector mixing tube support columns 52; the universal wheels 53 form a guiding contact with the outer wall of the air separator cylinder 3. The universal wheels 53 form a guiding contact with the outer wall of the air separator cylinder 3, which has the function of guiding and centering. It can help the ejector mixing tube 5 maintain the correct position and orientation during installation and adjustment, and ensure correct docking with other components, thereby improving the accuracy and reliability of installation.

[0054] In some embodiments, the burner further includes a nitrogen oxide sensor and a burner controller 93; both the regulating servo 9 and the nitrogen oxide sensor are connected to the burner controller 93. The nitrogen oxide sensor is typically installed at the exhaust port of the furnace to monitor the emission level of nitrogen oxides generated in the combustion gases. It can measure the concentration of nitrogen oxides emitted by the burner to detect and monitor the burner's operating status in a timely manner. The burner controller 93 receives signals from the nitrogen oxide sensor and adjusts the burner's operating parameters based on the monitored nitrogen oxide concentration information to achieve low-NOx combustion. The burner controller primarily controls the regulating servo 9, which in turn controls the ejector flue gas flow regulating mechanism to automatically adjust the ejector flue gas flow, minimizing the generation and emission of nitrogen oxides.

[0055] In operation, combustion air enters the burner head from the air intake section 1, flows through the air pipe 4, air separator 3, and air ejector mixing pipe 5, and then exits the burner head. After entering the burner head from the air intake section 1, the combustion air flows into the air pipe 4 and is divided into two parts by the air separator 3. One part of the air flows along the channel between the air separator 3 and the central gas main pipe 7 and, as it flows through the flame stabilizer 8, is ejected from the air holes 81 of the flame stabilizer 8 and the channel between the edge of the flame stabilizer 8 and the air separator 3, forming the intermediate air. The remaining air continues to flow along the channel between the air separator 3 and the air pipe contraction cone section 41, and, affected by the contraction of the area of ​​the air pipe contraction cone section 41, forms an accelerated airflow. It then continues to flow into the channel between the air ejector mixing pipe 5 and the air separator 3, and after further development, is ejected to form the outermost air. This creates a graded airflow state of intermediate and outermost air.

[0056] The outer ring plate 21 of the intake ring cavity, the outer tube plate 22 of the intake ring cavity, the inner expansion plate 23 of the intake ring cavity, and the inner tube plate 24 of the intake ring cavity form the intake ring cavity; after the gas flows from the gas intake pipe 2 into the intake ring cavity, it is divided into two parts.

[0057] The first part of the gas flows along the central gas vertical connecting section 71 into the central gas main pipe 7 and is then ejected from the central main pipe radial nozzle 75, the central main pipe radial nozzle 76, and the main pipe radial premixing nozzle 72. The gas ejected radially from the central main pipe radial nozzle 75 mixes with the intermediate air and is ejected to form a central flame region downstream. This region has a low air volume, resulting in oxygen-deficient combustion, a low combustion temperature, and a chemically reducing atmosphere, reducing NOx formation. Because the air impacts the flame stabilizer 8 and forms a bluff body recirculation region downstream, the central flame region has the function of entraining the downstream high-temperature flue gas into the bluff body recirculation region to re-ignite the unburned mixture, thus forming a stable flame region. The combustion gas ejected from the main radial nozzle 76 mixes with the axially flowing intermediate air. This vertical mutual impact mixing method makes the mixing very uniform. This part of the mixture forms an intermediate flame region downstream. This part of the mixer has excess air, forming lean fuel combustion, with a low combustion temperature and reduced NOx generation. After the combustion gas ejected from the main radial premixed nozzle 72 mixes with the peripheral air, the mixture is further mixed under the action of the air pipe contraction cone section 41. After being fully mixed and developed in the channel between the air ejector mixing pipe 5 and the air separator cylinder 3, it is ejected to form an intermediate premixed flame region. This region is a lean fuel premixed combustion region with a low combustion temperature and reduced NOx generation.

[0058] The remaining gas flows downstream after being ejected from the nozzle of the outer gas branch pipe 6. It entrains the remaining air in the lean fuel premixed combustion zone and mixes it for combustion, forming the outer flame zone. This part of the flame is rich fuel combustion, with a low combustion temperature, which reduces the formation of NOx. It also forms a reburning flame reduction atmosphere downstream, avoiding the formation of high-temperature NOx.

[0059] As the premixed gas contracts within the constriction cone section 41 of the air pipe, its velocity continuously increases. This increased velocity creates a negative pressure ejection effect, causing downstream flue gas to continuously flow back through the channel formed by the constriction cone section 41 and the air ejector constriction section 51, where it mixes with the premixed gas. The cooling and suppression effect of the flue gas lowers the combustion flame temperature, reducing the formation of nitrogen oxides. The swirling flow in each combustion zone generates mixing and shearing effects, resulting in intense material and heat transfer, collectively forming a stable and efficient combustion zone.

[0060] During combustion, the burner controller 93 receives the nitrogen oxide emission values ​​of the combustion products in real time and sets the maximum fluctuation threshold and maximum duration of the nitrogen oxide emission value. When the nitrogen oxide emission value fluctuates and the change value exceeds the maximum fluctuation threshold for an extended period beyond the maximum duration, the burner controller 93 controls the regulating servo 9 to rotate the regulating servo shaft 91. Through the linkage of the coupling 92, the regulating screw 10 also rotates simultaneously. Since the screw thread section 101 at the end of the screw 10 and the screw nut 102 form a threaded connection, the screw nut 102 and the axial tie rod 103 can move along the axis of the air pipe 4. Simultaneously, the movement of the axial tie rod 103 pulls the air ejector retraction section 51 to move. The flue gas ejection channel formed between the air ejector constriction section 41 and the air ejector mixing tube 51 has changed. Since the air ejector constriction section 51 and the air ejector mixing tube 5 are fixedly connected, the air ejector mixing tube 5 will also move with the air ejector constriction section 51. Several ejector mixing tube support columns 52 are evenly installed in the middle of the air ejector mixing tube 5. Universal wheels 53 are installed at the ends of the ejector mixing tube support columns 52. The universal wheels 53 form a guiding contact with the outer wall of the air separator cylinder 3. The universal wheels 53 can change the surface contact between the ejector mixing tube support column 52 and the outer wall of the air separator cylinder 3 to a point contact between the universal wheels 53 and the outer wall of the air separator cylinder 3. This can reduce the resistance during the movement of the air ejector mixing tube 5, and finally realize the control of the ejected flue gas flow rate, thereby regulating the concentration of nitrogen oxides.

[0061] The above provides a detailed description of a performance-adaptive low-NOx burner provided by the present invention. The specific embodiments described are merely for the purpose of aiding understanding the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A performance-adaptive low-NOx burner, the burner comprising an air intake section (1) and an intake annular cavity, characterized in that: The outer wall of the intake ring cavity is connected to a gas intake pipe (2); the inner wall of the intake ring cavity is connected to a central gas vertical connecting section (71); the tail end of the central gas vertical connecting section (71) is connected to a central gas main pipe (7); the central gas main pipe (7) is covered with an air separator cylinder (3); several radial premixed nozzles (72) are evenly distributed on the central gas main pipe (7) near the inlet of the air separator cylinder (3); several support rods (31) are evenly distributed in the middle of the central gas main pipe (7), and the other end of the support rods (31) is fixedly connected to the air separator cylinder (3); Multiple peripheral gas branch pipes (6) are evenly arranged on the side wall of the air intake ring cavity; the tail of the air intake ring cavity is provided with an air pipe (4), an air pipe contraction cone section (41), an air ejector contraction section (51) and an air ejector mixing pipe (5) in sequence from the air intake section (1) to the air separator cylinder (3). The burner includes an ejector flue gas volume adjustment mechanism; the ejector flue gas volume adjustment mechanism is connected to the air pipe contraction cone section (41) and the air ejector contraction section (51) and is used to adjust the relative position of the air pipe contraction cone section (41) and the air ejector contraction section (51); The burner also includes a nitrogen oxide sensor and a burner controller (93); the regulating servo (9) and the nitrogen oxide sensor are both connected to the burner controller (93).

2. The performance-adaptive low-NOx burner according to claim 1, characterized in that: The ejector flue gas volume adjustment mechanism includes, from left to right, an adjustment servo (9), an adjustment servo shaft (91), a coupling (92), and a spiral structure. The spiral structure includes a spiral rod sleeve (25), an adjustment spiral rod (10), and a spiral rod threaded section (101). The adjustment spiral rod (10) is partially sleeved inside the spiral rod sleeve (25). The end of the adjustment spiral rod (10) away from the adjustment servo (9) is connected to the spiral rod threaded section (101). The spiral rod threaded section (101) is coaxially sleeved with a spiral rod nut (102), and the two form a threaded connection structure. An axial tie rod (103) is provided at the end of the spiral rod nut (102) away from the adjustment spiral rod (10). One end of the axial tie rod (103) is fixedly connected to the spiral rod nut (102), and the other end passes through the air pipe contraction cone section (41) and is fixedly connected to the air ejector contraction section (51).

3. The performance-adaptive low-NOx burner according to claim 2, characterized in that: The air pipe contraction cone section (41) is connected to the air pipe (4), and the air pipe contraction cone section (41) and the air pipe (4) form an interior angle of 90-180°; the air ejector contraction section (51) is connected to the air ejector mixing pipe (5); the air pipe contraction cone section (41) and the air ejector contraction section (51) are arranged in parallel and have a certain interval.

4. The performance-adaptive low-NOx burner according to claim 3, characterized in that: A flame stabilizer plate (8) is installed at the downstream end of the central gas main pipe (7). A number of central gas main pipe radial nozzles (75) and central gas main pipe radial nozzles (76) are evenly distributed between the flame stabilizer plate (8) and the central gas main pipe (7). Flame stabilizer plate air holes (81) are evenly arranged between the central gas main pipe radial nozzles (76).

5. A performance-adaptive low-NOx burner according to claim 4, characterized in that: The gas passage area of ​​the central main radial nozzle (75) accounts for 4% to 10% of the total gas outlet area.

6. A performance-adaptive low-NOx burner according to claim 5, characterized in that: The intake ring cavity is composed of an outer ring plate (21), an outer tube plate (22), an inner expansion plate (23), and an inner tube plate (24). The inner expansion plate (23) is an expansion slope, which is used to achieve smooth flow of combustion air from the air intake section (1) into the air pipe (4) and reduce pressure loss.

7. A performance-adaptive low-NOx burner according to claim 6, characterized in that: The peripheral gas branch pipe (6) and the air ejector retraction section (51) are clearance-fitted, which facilitates the movement of the air ejector retraction section (51) and the air ejector mixing pipe (5) along the axial direction of the air ejector mixing pipe (5).

8. A performance-adaptive low-NOx burner according to claim 7, characterized in that: The axial tie rod (103) and the air tube contraction cone section (41) are fitted with a clearance, which facilitates the axial movement of the axial tie rod (103) along the axial direction of the air ejector mixing tube (5).

9. A performance-adaptive low-NOx burner according to claim 5, characterized in that: Several ejector mixing tube support columns (52) are evenly installed in the middle of the air ejector mixing tube (5); universal wheels (53) are installed at the ends of the ejector mixing tube support columns (52); the universal wheels (53) form a guiding contact with the outer wall of the air separator cylinder (3).

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