Annular stratified gas low NO x burner

Abstract

This invention discloses an annular stratified flow low-NOx burner, comprising an outer cylinder, an ignition gun, a swirl-stabilized combustion plate, an annular primary gas orifice plate, a primary gas jacket, a primary gas connecting pipe, a primary gas header, an annular secondary gas orifice plate, a secondary gas jacket, a secondary gas connecting pipe, a secondary gas header, a primary air regulating sleeve assembly, a tertiary air regulating sleeve assembly, and an insulation and sealing assembly, among other main components. The burner's air inlet channels include a primary air channel, a secondary air channel, and a tertiary air channel, which can be expanded outwards to form N secondary air channels. A concentric annular channel structure and a radially staggered arrangement of the primary, secondary, and (N-1) secondary gas channels enable stratified flow multi-stage air grading and fuel grading combustion. When flue gas recirculation technology is employed, this burner can achieve ultra-low NOx emissions of less than 30 mg / Nm3 at the combustion chamber outlet, while simultaneously solving problems such as unstable combustion, reduced burnout, and burner vibration.

Description

Technical Field

[0001] This invention relates to a gas burner, and more particularly to a low-NOx burner. Background Technology

[0002] Scientific research has found that nitrogen oxides (NOx) pose serious threats to human health and the atmospheric environment. NOx sources are widespread; combustion equipment in industries such as petrochemicals, metallurgy, machinery, and power generates large amounts of NOx emissions. These emissions not only cause environmental problems such as acid rain, plant damage or death, ozone layer depletion, and photochemical smog, but also directly damage the human respiratory system, threatening human health. In response to increasingly serious environmental problems, my country has introduced strict NOx emission standards. Therefore, the development of combustion equipment with low NOx emissions is of great significance.

[0003] Based on the different comprehensive formation mechanisms of NOx, nitrogen oxides can be divided into thermal NOx, fuel NOx, and rapid NOx. Among them, the formation of thermal NOx and rapid NOx is mainly dominated by the premixed combustion, partially premixed combustion, and diffusion combustion of high-calorific-value fuels such as natural gas. From the perspective of formation mechanism, thermal NOx is greatly affected by temperature, but rapid NOx is less affected by temperature. Compared with thermal NOx, rapid NOx has more stringent formation conditions and will only be produced when fuel is sufficient and oxygen is relatively scarce. Once formed, its reaction rate is very fast and it spreads rapidly on the flame.

[0004] Currently, most low-NOx gas burners used in industry are designed and invented based on the NOx formation mechanism. They control NOx generation by reducing the temperature of the combustion zone, reducing the oxygen concentration in the combustion zone, and shortening the combustion time of the gas in the high-temperature zone. However, different low-NOx gas burners have different technical focuses and can be roughly divided into the following categories: (1) flue gas recirculation type low-NOx burner; (2) staged combustion type low-NOx burner; (3) mixing-promoting type low-NOx burner; (4) segmented flame type low-NOx burner, etc.

[0005] Most domestic low-NOx gas burner designs and inventions focus on only one or two of the above technologies, which leads to neglecting one aspect for another. For example, some burners focus on flue gas recirculation technology, which reduces NOx emissions, but is prone to unstable combustion, strong vibration problems, and even flameout of the entire burner. At the same time, reducing the furnace combustion temperature may also lead to a decrease in overall thermal efficiency. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a gas burner with a high regulation ratio suitable for burning high-calorific-value fuel gas. Through staged fuel delivery, annular stratified air distribution, flame segmentation, and rational jet organization, it achieves stable combustion and burnout characteristics at a high regulation ratio, while suppressing NOx formation within the combustion zone. A further optimized scheme can achieve NOx levels of 30 mg / Nm³ at the combustion chamber outlet of large boilers and kilns. 3 While reducing NOx emissions, it also addresses challenging issues such as unstable combustion, reduced burnout, and burner vibration.

[0007] The technical solution adopted by this invention to solve its technical problem is: an annular stratified flow low-NOx burner, the burner including an ignition gas gun sleeve located at its center for installing an ignition device, an outer cylinder coaxially arranged outside the ignition gas gun sleeve, a front insulation and sealing assembly arranged at the front end of the outer cylinder, and a rear insulation and sealing assembly arranged at the rear end of the outer cylinder, the burner's air inlet channel including a primary air channel and secondary air channels and tertiary air channels arranged around it, the ignition gas gun sleeve having a primary gas channel and a secondary gas channel arranged outwards.

[0008] The primary gas passage consists of an annular primary gas orifice plate and a primary gas jacket forming the front end of the gas passage. The primary gas jacket is connected to the primary gas header via a primary gas connecting pipe to form a primary gas assembly. The secondary gas passage consists of an annular secondary gas orifice plate and a secondary gas jacket forming the front end of the gas passage. The secondary gas jacket is connected to the secondary gas header via a secondary gas connecting pipe to form a secondary gas assembly. The annular primary gas orifice plate and the annular secondary gas orifice plate have inwardly inclined inner gas nozzle holes and outwardly inclined outer gas nozzle holes.

[0009] The front end of the primary air channel is a central annular air duct formed by the ignition gas gun sleeve and the inner wall of the primary gas jacket; the front end of the secondary air channel is an inner annular air duct formed by the outer wall of the primary gas jacket and the inner wall of the secondary gas jacket; the front end of the tertiary air channel is an outer annular air duct formed by the outer wall of the secondary gas jacket and the inner wall of the outer cylinder. The ratio of primary, secondary and tertiary air is adjustable.

[0010] The burner adopts an annular gas jacket structure design, forming multiple concentric annular structures in the radial direction of the burner. By matching the size of the gas jacket, gas jet parameters and air supply parameters, annular layered combustion is formed at the front end of the burner, and multi-level lean combustion layers are formed in the radial direction, which reduces the local flame temperature and suppresses the formation of thermal NOx.

[0011] Both the annular primary gas orifice plate and the annular secondary gas orifice plate have an inner inclined surface and an outer inclined surface at the front end of the gas orifice plate, respectively. Inner gas nozzle holes are evenly distributed circumferentially on the inner inclined surface at the front end of the gas orifice plate, and outer gas nozzle holes are evenly distributed circumferentially on the outer inclined surface at the front end of the gas orifice plate. The axis of each gas nozzle hole is perpendicular to its respective inclined surface, and the obtuse angle α between the inclined surface and the plane perpendicular to the burner axis is 110° to 170°. This design facilitates the machining of the gas nozzle holes and the achievement of the gas injection angle relative to the burner axis.

[0012] The central annular air duct is connected to the primary air duct to form a primary air channel. The primary air duct is divided into a conical section and a straight section. The large-diameter end of the conical section is connected to the rear end of the primary gas jacket. Primary air openings are evenly arranged circumferentially on the straight section. A primary air regulating sleeve assembly is correspondingly provided on the straight section. The primary air volume can be changed by adjusting the front and rear positions of the primary air regulating sleeve.

[0013] The secondary air duct is composed of an outer cylinder and a rear insulation and sealing assembly forming an air chamber at its rear end. There are multiple air holes along the circumference at the rear end of the outer cylinder. The air supplied by the burner enters the secondary air duct and the primary air duct through the air holes respectively.

[0014] An annular baffle is welded between the rear end of the secondary gas jacket and the outer cylinder to divide the secondary air passage and the tertiary air passage. The outer cylinder at the front end of the annular baffle has tertiary air openings evenly distributed around the circumference, and a tertiary air regulating sleeve assembly is arranged on the outer cylinder. The tertiary air volume can be changed by adjusting the front and rear positions of the tertiary air regulating sleeve.

[0015] The primary gas assembly and the primary air and air conditioning assembly are connected as a single unit and can be extracted entirely from the rear of the burner. The secondary gas assembly and the tertiary air and air conditioning assembly are connected as another single unit and can also be extracted entirely from the rear of the burner.

[0016] For ease of maintenance, the primary gas assembly and the primary air and air regulating assembly are connected as a whole and can be extracted from the rear of the burner as a whole. The secondary gas assembly and the tertiary air and air regulating assembly are connected as another whole and this other whole can be extracted from the rear of the burner as a whole.

[0017] The ignition device is arranged on the central axis of the burner. A swirl stabilizing plate is arranged on the outside of the ignition gas gun sleeve for stabilizing the central flame. The ignition gas gun is fixed inside the ignition gas gun sleeve by the tail flange. The high-energy ignition gun is arranged inside the ignition gas gun sleeve and is fixed by a cylinder actuator.

[0018] The swirl stabilizing flame plate is equipped with an ignition detection sleeve for installing flame detectors. The front end of the outer cylinder is connected to an expansion cone, and two main flame detection sleeves are arranged on the upper part of the expansion cone for installing two main flame detection devices.

[0019] The primary gas connection pipes are evenly arranged circumferentially on the primary gas header, with a number between 5 and 20, and gas is introduced into the primary gas header from the primary gas main pipe; the secondary gas connection pipes are evenly arranged circumferentially on the secondary gas header, with a number between 5 and 20, and gas is introduced into the secondary gas header from the secondary gas main pipe.

[0020] Gas nozzle holes are evenly arranged along the inner and outer circumferential walls at the front end of the primary gas jacket and the secondary gas jacket.

[0021] The concentric annular channel structure of the burner can be expanded to have N secondary air channels, where N is a positive integer greater than 3. The secondary gas channel of the burner is extended outward by N-1 secondary gas channels.

[0022] The beneficial effects of this invention are as follows: In the annular stratified flow low-NOx burner, the gaseous fuel is fed in multiple paths. One path is fed through an ignition gun for ignition, another through a primary gas main, and a third through a secondary gas main. This can be arranged into N gas mains as needed. Both the primary and secondary gas inlet channels are annular headers. The gas enters the multiple gas connection pipes through these annular headers. By rationally designing the cross-sectional dimensions of the gas connection pipes, the back pressure of the gas can be consumed, achieving pressure matching between the primary and secondary gas. Gas nozzles with different angles are provided on both the inner and outer sides of the annular primary and secondary gas orifice plates, avoiding concentrated fuel injection. After entering the burner, the fuel is evenly injected into the furnace, achieving fuel grading. The primary gas is ejected through the primary gas nozzle orifice. A portion of the fuel ejected from the primary gas nozzle orifice forms an airflow inclined towards the axis. This airflow is evenly distributed circumferentially and fully mixes with the primary air for combustion. Part of the gas ejected from the secondary gas nozzle orifice forms an airflow inclined towards the axis, which mixes thoroughly with the high-temperature products generated by the combustion of the fuel ejected from the primary gas nozzle orifice. Combined with air supply matching, this achieves reducing atmosphere control during combustion, which helps reduce NOx. The outermost layer consists of secondary fuel ejected from the secondary fuel nozzle orifice, which mixes thoroughly with tertiary air for combustion. The primary and secondary gas nozzle orifices are radially distributed, achieving staged combustion. This fuel staged technology allows some fuel to burn under oxygen-rich conditions (excess air coefficient greater than 1), avoiding the formation of large amounts of rapid-burning nitrogen oxides caused by combustion under equivalence ratio conditions. Other fuel burns under fuel-rich conditions, generating a large amount of reducing hydrocarbons and producing a reducing atmosphere, which reduces nitrogen oxides generated during combustion in the furnace, thereby reducing nitrogen oxide emissions.

[0023] The excess air coefficient of the gaseous fuel burner does not exceed 1.05, ensuring that the gaseous fuel burns under conditions of low excess oxygen concentration, thus reducing NOx emissions. The air is divided into primary air, secondary air, and tertiary air. The air volume distribution of each type of air is controlled by the coordinated adjustment of the primary air regulating sleeve assembly and the tertiary air regulating sleeve assembly, thereby controlling the combustion to be in the optimal state and keeping the NOx emissions at the furnace outlet at the lowest level.

[0024] Based on the combustion method described above, high-speed primary fuel is ejected from the inner primary fuel nozzle orifice towards the axis, where it mixes intensely with primary air and burns violently under low-oxygen conditions, generating a small amount of NOx. Simultaneously, a gas stream is ejected from the outer primary fuel nozzle orifice, flowing away from the axis, and mixes intensely with secondary air, burning violently under low-oxygen conditions and generating a small amount of NOx. By controlling the ratio of primary and secondary air, the primary fuel separated by the inner and outer primary fuel nozzles can operate at a stoichiometric ratio of 1 or higher. This suppresses NOx formation during combustion in a longer region at the burner outlet center. During this process, some reducing intermediate media are also generated, reducing the already generated NOx. Furthermore, in the middle and later stages of combustion, tertiary air provides oxygen to ensure complete combustion of unburned gas. This combustion mode is a staged air combustion mode with low NOx emissions. By controlling the ratio of primary air to secondary air, the stoichiometric ratio of the primary fuel is made less than 1. Excess oxygen combustion occurs in the outlet area of ​​the burner, and the large amount of NOx produced mixes with some of the secondary fuel injected from the inner nozzle of the secondary fuel. The reducing groups in the fuel reduce the NOx produced by the primary fuel to nitrogen. The tertiary air from the outer side of the secondary fuel is then mixed in to achieve complete combustion of the fuel gas components.

[0025] The outer layer of the burner outlet features a secondary fuel nozzle. A portion of the secondary fuel is ejected through the inner secondary fuel nozzle, mixing with the secondary air and the combustion products of the primary fuel. The combustion of the secondary fuel creates a partially reducing atmosphere. When mixed with the combustion products of the primary fuel, the reducing groups collide with the NOx generated during the primary combustion process, reducing it to nitrogen. Additionally, a small amount of unburned secondary fuel and some reducing substances are completely burned after mixing with the tertiary air. The secondary fuel's location on the periphery of the secondary air helps prevent escape and achieves combustion with a low excess air coefficient. The portion of secondary fuel ejected through the outer secondary fuel nozzle mixes thoroughly with the tertiary air. By controlling the ratio of secondary to tertiary air, the stoichiometric ratio of the secondary fuel ejected from the inner and outer nozzles can be kept below 1, reducing NOx formation. This burner, employing radial staged combustion, effectively reduces NOx emissions and exhibits excellent denitrification performance. The first and second stage fuel gases are intensely mixed with primary, secondary, and tertiary air respectively, with an excess of air, resulting in complete combustion of the fuel gases and high combustion efficiency of the gaseous fuels.

[0026] In summary, this invention, by applying multiple low-NOx combustion technologies coupled with annular stratified flow technology, achieves ultra-low NOx emissions while ensuring high burnout rates for gaseous fuels. This burner is suitable for heating furnaces, kilns, and boilers in the petrochemical, metallurgical, machinery, and power industries that use high-calorific-value fuel gases. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the burner of the present invention.

[0028] Figure 2 This is a schematic diagram of the burner nozzle end of the present invention.

[0029] Figure 3 This is the front view of the annular primary gas orifice plate.

[0030] Figure 4 yes Figure 3 Top view.

[0031] The markings in the diagram are as follows: 1-Annular primary gas orifice plate, 2-Expanding cone, 3-Front insulation and sealing assembly, 4-Primary gas jacket, 5-Outer cylinder, 6-Primary gas connecting pipe, 7-Primary gas header, 8-Primary gas main pipe, 9-Tertiary air regulating sleeve assembly, 10-Rear insulation and sealing assembly, 11-Main flame detector sleeve, 12-Ignition gas gun sleeve, 13-High-energy ignition gun, 14-Ignition gas gun, 15-Swirl combustion stabilizing disc, 16-Annular secondary gas orifice plate, 17-Secondary gas Jacket, 18-Primary air duct, 19-Primary air regulating sleeve assembly, 20-Secondary gas connection pipe, 21-Secondary gas header, 22-Secondary gas main pipe, 23-Ignition flame detection sleeve, 24-Annular partition, 25-Tail flange, 101-External gas nozzle hole, 102-Internal gas nozzle hole, 103-Outer bevel at the front end of gas orifice plate, 104-Inner bevel at the front end of gas orifice plate, 180-Primary air opening section, 500-Air hole opening section, 510-Tertiary air opening section. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, the annular stratified flow low-NOx burner of the present invention includes an annular primary gas orifice plate 1, an expansion cone 2, a front insulation and sealing assembly 3, a primary gas jacket 4, an outer cylinder 5, a primary gas connecting pipe 6, a primary gas header 7, a primary gas main pipe 8, a tertiary air regulating sleeve assembly 9, a rear insulation and sealing assembly 10, a main flame detection sleeve 11, an ignition gun sleeve 12, a high-energy ignition gun 13, an ignition gun 14, a swirl combustion stabilizing disc 15, an annular secondary gas orifice plate 16, a secondary gas jacket 17, a primary air duct 18, a primary air regulating sleeve assembly 19, a secondary gas connecting pipe 20, a secondary gas header 21, a secondary gas main pipe 22, an ignition flame detection sleeve 23, a sealing steel plate and flanges, and other components.

[0034] The basic structure of the annular stratified flow low-NOx burner includes a primary gas passage and a secondary gas passage arranged coaxially. The primary gas passage consists of an annular primary gas orifice plate 1 and a primary gas jacket 4 forming the front end of the gas passage. The primary gas jacket 4 is connected to a primary gas header 7 by multiple primary gas connecting pipes 6, and gas is finally introduced into the primary gas header 7 through a primary gas main pipe 8. The secondary gas passage consists of an annular secondary gas orifice plate 16 and a secondary gas jacket 17 forming the front end of the gas passage. The secondary gas jacket 17 is connected to a secondary gas header 21 by multiple secondary gas connecting pipes 20, and gas is finally introduced into the secondary gas header 21 through a secondary gas main pipe 22.

[0035] The ignition device of the annular stratified flow low-NOx burner is arranged in the center of the burner. The ignition device consists of an ignition gun sleeve 12, a high-energy ignition gun 13, and an ignition gun 14. A swirl combustion stabilizing plate 15 is arranged outside the ignition gun sleeve 12. During ignition, the gas mixes with the swirling primary air at a certain angle through the nozzle hole of the ignition gun and is then ignited by the high-energy ignition gun 13. The ignition gun 14 is fixedly arranged. After ignition, the high-energy ignition gun 13 retracts to a position of 200-500mm in the inner tube of the ignition gun. An ignition flame detection sleeve 23 is arranged in the swirl combustion stabilizing plate 15 to realize the monitoring of the combustion flame during ignition.

[0036] like Figure 1 and Figure 2As shown, the air intake channel of the annular stratified flow low-NOx burner includes a primary air channel located at the center of the burner and secondary and tertiary air channels surrounding it. The front end of the primary air channel is formed by the ignition gas gun sleeve 12 and the inner wall of the primary gas jacket 4, creating an annular air duct, which then connects to the primary air duct 18. The primary air duct 18 is divided into a conical section and a straight section. The larger diameter end of the conical section connects to the rear end of the primary gas jacket 4, and the smaller diameter end connects to the front end of the straight section. A primary air regulating sleeve assembly 19 is arranged on the straight section. Air enters the primary air duct 18 through multiple openings on the straight section. These openings are evenly distributed around the circumference of the primary air duct 18 to ensure uniform airflow. When the primary air regulating sleeve is closed, it fully covers the primary air openings. The primary air volume can be changed by adjusting the front and rear positions of the primary air regulating sleeve.

[0037] like Figure 1 and Figure 2 As shown, the front end of the secondary air duct is formed by the outer wall of the primary gas jacket 4 and the inner wall of the secondary gas jacket 17, creating an annular air duct. The rear end of the secondary air duct is formed by the outer cylinder 5 and the rear insulation and sealing assembly 10, creating an air chamber. Multiple air holes are located circumferentially at the rear end of the outer cylinder 5. Air is supplied through these air holes into the secondary air duct. By controlling the total air supply of a single burner, the secondary air volume can be indirectly adjusted by changing the primary and tertiary air volumes, thereby adjusting the flame shape and controlling the combustion speed.

[0038] like Figure 1 and Figure 2 As shown, the front end of the tertiary air duct is formed by the outer wall of the secondary gas jacket 17 and the inner wall of the outer cylinder 5, creating an annular air duct. An annular partition 24 is welded to the rear end of the outer wall of the secondary gas jacket 17 to separate the secondary air duct and the tertiary air duct. A tertiary air regulating sleeve assembly 9 is arranged on the outer cylinder 5. The supplied air enters the tertiary air duct through multiple tertiary air openings in the middle region of the outer cylinder. The tertiary air openings are evenly arranged around the circumference of the outer cylinder 5 to ensure uniform air supply. When the tertiary air regulating sleeve is closed, it can fully cover the tertiary air openings. The tertiary air volume can be changed by adjusting the front and rear positions of the tertiary air regulating sleeve.

[0039] The outer cylinder 5 is connected to the front end of the expansion cone 2. The expansion cone 2 is used to shape the flame and protect the front end components of the burner. The upper part of the expansion cone 2 is provided with the main flame detection sleeve 11, which is used to install the flame detection device to realize combustion monitoring.

[0040] Preferably, the shape of the main air duct of the present invention can be square or circular. The main air duct is composed of a front insulation and sealing component 3, an outer cylinder 5, a rear insulation and sealing component 10 and a sealing steel plate to form a main air chamber for a single burner. The total air volume is remotely controlled by the main air damper.

[0041] Preferably, the primary air duct, secondary air duct, and tertiary air duct are concentrically arranged with the ignition gas gun sleeve 12. After the gas is diverted, it is divided into primary and secondary fuels, realizing staged combustion of fuel and air, which is beneficial to reducing NOx emissions. This burner has a simple structure and can easily expand outwards. It can be further expanded outwards according to the aforementioned basic arrangement structure into N secondary air ducts and (N-1) secondary gas ducts, where N is a positive integer greater than 3.

[0042] like Figure 3 and Figure 4 As shown, the annular primary gas orifice plate 1 and the annular secondary gas orifice plate 16 have the same structure but different diameters and the number of gas holes. Each gas orifice plate is provided with an inner gas nozzle hole 102 and an outer gas nozzle hole 101. The annular primary gas orifice plate 1 and the annular secondary gas orifice plate 16 are respectively formed with an inner inclined surface 104 and an outer inclined surface 103 at the front end of the gas orifice plate to facilitate the processing of gas nozzle holes. The inner gas nozzle holes 102 are evenly distributed circumferentially on the inner inclined surface 104 at the front end of the gas orifice plate, and the outer gas nozzle holes 101 are evenly distributed circumferentially on the outer inclined surface 103 at the front end of the gas orifice plate. The axis of each gas nozzle hole is perpendicular to the inclined surface on which it is located. The obtuse angle α between the outer inclined surface 103 at the front end of the gas orifice plate and the plane perpendicular to the burner axis is 110° to 170°. The axes of the internal gas nozzle holes 102 and the external gas nozzle holes 101 may have the same or different obtuse angles with the plane perpendicular to the burner axis, preferably between 110° and 170°. The gas nozzle holes are evenly distributed circumferentially on the gas orifice plate, with the number preferably determined by the gas flow rate. The internal gas nozzle holes 102 and the external gas nozzle holes 101 may be arranged either staggered or in a straight line circumferentially.

[0043] The shape of the gas nozzle orifice can be a circular nozzle orifice, an elliptical nozzle orifice, an oval nozzle orifice, or a slit nozzle orifice with an irregular cross-section.

[0044] The primary gas connection pipes 6 are evenly arranged circumferentially on the primary gas header 7, with a preferred number between 5 and 20. In addition to transporting gas, they are also important supporting components of the primary gas assembly.

[0045] The secondary gas connection pipes 20 are evenly arranged circumferentially on the secondary gas header 21, with a preferred number between 5 and 20. In addition to transporting gas, they are also important supporting components of the secondary gas assembly.

[0046] The primary gas header 7 and the secondary gas header 21 can be arranged inside the air duct or outside the air duct, that is, outside the rear panel of the burner. Figure 2 As shown, the primary gas header 7 is arranged inside the air duct, while the secondary gas header 21 is arranged outside the air duct.

[0047] The primary gas header 7 and the secondary gas header 21 can be, structurally speaking, annular headers made of pipes or annular cylindrical headers.

[0048] The primary gas jacket 4 and the secondary gas jacket 17 can also have gas nozzle holes evenly arranged on the inner and outer walls along the circumferential direction at the front end, so as to realize partial premixed combustion of gas and air, which is conducive to complete combustion and reduction of NOx emissions.

[0049] Swirl blades can be arranged at the front end of the secondary air duct and the front end of the tertiary air duct. Figure 1 and Figure 2 The swirl blades are not shown in the figure. The blade installation angle is preferably between 25° and 75° to achieve swirl of secondary or tertiary air, enhance the mixing of gas and air supply, and facilitate complete combustion.

[0050] The ignition device assembly inside the ignition gun sleeve is integrated with the primary gas assembly and the primary air regulating assembly as a whole. It can be pulled out from the rear for easy maintenance. After disconnecting the connection at the tail flange, the ignition device assembly can be pulled out separately from the rear of the whole for easy maintenance after operation. The secondary gas assembly, tertiary air and regulating assembly can be pulled out as a whole from the rear of the burner for easy maintenance after operation.

[0051] Preferably, the air supply of the annular stratified flow low-NOx burner can be air, a mixture of air and flue gas, or a mixture of pure oxygen and air. When it is a mixture of air and flue gas, the oxygen content of the supply air is preferably between 12% and 18%, and NOx emissions are further reduced by utilizing flue gas recirculation technology.

[0052] Example 1:

[0053] refer to Figure 2 ,like Figure 1 , Figure 3 and Figure 4 As shown, the basic structure of the annular stratified flow low-NOx burner in this embodiment includes a primary gas channel and a secondary gas channel, which can be expanded outward to N-1 secondary gas channels, where N is a positive integer greater than 3. The primary gas channel consists of an annular primary gas orifice plate 1 and a primary gas jacket 4 forming the inner and outer annular surfaces for gas injection. The primary gas jacket 4 is connected to a primary gas header 7 by multiple primary gas connecting pipes 6, and gas is ultimately introduced into the primary gas header 7 through a primary gas main pipe 8. The secondary gas channel consists of an annular secondary gas orifice plate 16 and a secondary gas jacket 17 forming the inner and outer annular surfaces for gas injection. The secondary gas jacket 17 is connected to a secondary gas header 21 by multiple secondary gas connecting pipes 20, and gas is ultimately introduced into the secondary gas header 21 through a secondary gas main pipe 22. This structure achieves staged combustion of fuel.

[0054] The ignition device of the burner described in this invention is arranged on the central axis of the burner. A swirl stabilizing flame plate 15 is arranged on the outside of the ignition gas gun sleeve 12 for stabilizing the central flame. The ignition gas gun 14 is fixed inside the ignition gas gun sleeve 12 by the tail flange 25 and can be disassembled for maintenance. The high-energy ignition gun 13 is arranged inside the sleeve of the ignition gas gun 14. The high-energy ignition gun 13 is fixed by a cylinder actuator. After ignition for 10 to 15 seconds, it retracts to a position 200 to 500 mm inside the inner tube 12 of the ignition gas gun. An ignition flame detection sleeve 23 is arranged in the swirl stabilizing flame plate 15 to realize the monitoring of the combustion flame during ignition.

[0055] The air intake passage of the burner includes a primary air passage, a secondary air passage, and a tertiary air passage, and can be expanded outward to N secondary air passages. It adopts a concentric circle channel structure and the primary gas passage, secondary gas passage, and N-1 secondary gas passage are arranged radially in a staggered manner to achieve stratified flow and multi-stage air classification, so as to reduce NOx emissions.

[0056] The primary air duct is formed by an annular air duct at the front end by the ignition gas gun sleeve 12 and the inner wall of the primary gas jacket 4, and then connected to the primary air duct 18. The primary air duct 18 is divided into a conical section and a straight section. The large-diameter end of the conical section is connected to the rear end of the primary gas jacket, and the small-diameter end of the conical section is connected to the straight section. A primary air regulating sleeve assembly 19 is arranged on the straight section. Air is supplied through multiple openings on the straight section of the primary air duct into the primary air duct. The primary air openings are evenly arranged along the circumference of the primary air duct to ensure uniform air supply. The primary air volume can be changed by adjusting the front and rear positions of the primary air regulating sleeve.

[0057] The front end of the secondary air duct is formed by the outer wall of the primary gas jacket 4 and the inner wall of the secondary gas jacket 17, creating an annular air duct. The rear end of the secondary air duct is formed by the outer cylinder 5 and the rear insulation and sealing assembly 10, creating an air chamber. Multiple air holes are located circumferentially at the rear end of the outer cylinder 5. Air is supplied through these air holes and enters the secondary air duct and the primary air duct respectively. By controlling the total air supply of a single burner, the secondary air volume can be indirectly adjusted by changing the primary and tertiary air volumes, thereby adjusting the shape of the combustion flame and controlling the combustion speed.

[0058] The front end of the tertiary air duct is formed by the outer wall of the secondary gas jacket 17 and the inner wall of the outer cylinder 5, creating an annular air duct. An annular partition 24 is welded to the rear end of the outer wall of the secondary gas jacket 17 to separate the secondary air duct and the tertiary air duct. A tertiary air regulating sleeve assembly 9 is arranged on the outer cylinder 5. The supplied air enters the tertiary air duct through multiple tertiary air openings in the middle region of the outer cylinder 5. The tertiary air openings are evenly arranged along the circumference of the outer cylinder to ensure uniform air supply. When the tertiary air regulating sleeve assembly 9 is closed, it can fully cover the tertiary air openings. The tertiary air volume can be changed by adjusting the front and rear positions of the tertiary air regulating sleeve.

[0059] The outer cylinder 5 is connected to the front end of the expansion cone 2. Two main flame detection sleeves 11 are arranged on the upper part of the expansion cone 2 for installing two main flame detection devices. The two-to-one control method is adopted to realize combustion monitoring.

[0060] The main air duct is square in shape. The main air duct consists of a front insulation and sealing component 3, an outer cylinder 5, a rear insulation and sealing component 10, and a sealing steel plate, forming a single burner main air chamber. The total air volume is remotely controlled by the main air damper.

[0061] The annular primary gas orifice plate 1 and the annular secondary gas orifice plate 16 of the present invention have the same structure, but different diameters and the number of gas holes. Both the annular primary gas orifice plate 1 and the annular secondary gas orifice plate 16 have an inner inclined surface 104 and an outer inclined surface 103 at the front end of the gas orifice plate, respectively. Inner gas nozzle holes 102 are evenly distributed circumferentially on the inner inclined surface 104 at the front end of the gas orifice plate, and outer gas nozzle holes 101 are evenly distributed circumferentially on the outer inclined surface 103 at the front end of the gas orifice plate. The axis of each gas nozzle hole is perpendicular to the inclined surface on which it is located, and each gas nozzle hole is a small circular hole. The obtuse angle between the inner and outer inclined surfaces and the plane perpendicular to the burner axis is 140°. The gas nozzle holes are evenly distributed circumferentially on the gas orifice plate, and the inner gas nozzle holes 102 and the outer gas nozzle holes 101 are staggered circumferentially.

[0062] The primary gas connection pipes 6 are evenly arranged circumferentially on the primary gas header 7, and there are 6 of them. The secondary gas connection pipes 20 are evenly arranged circumferentially on the secondary gas header 21, and there are 6 of them. They are welded to the steel plate at the position of the rear insulation and sealing assembly 10 to provide support.

[0063] The primary gas header 7 is arranged inside the air duct and is a circular pipe annular header. The secondary gas header 21 is arranged outside the air duct and is a circular pipe annular header.

[0064] The ignition device assembly, primary gas assembly, and primary air and air regulating assembly can be extracted as a whole from the rear of the burner, facilitating shutdown maintenance after operation; the secondary gas assembly and tertiary air and air regulating assembly can also be extracted as a whole from the rear of the burner, facilitating shutdown maintenance after operation.

[0065] Example 2:

[0066] like Figures 1 to 4As shown, the basic structure of the burner in this embodiment includes a primary gas passage and a secondary gas passage. The primary gas passage consists of an annular primary gas orifice plate 1 and a primary gas jacket 4 forming the inner and outer annular surfaces for gas injection. The primary gas jacket 4 is connected to a primary gas header 7 by multiple primary gas connecting pipes 6, and gas is ultimately introduced into the primary gas header 7 through a primary gas main pipe 8. The secondary gas passage consists of an annular secondary gas orifice plate 16 and a secondary gas jacket 17 forming the inner and outer annular surfaces for gas injection. The secondary gas jacket 17 is connected to a secondary gas header 21 by multiple secondary gas connecting pipes 20, and gas is ultimately introduced into the secondary gas header 21 through a secondary gas main pipe 22. This structure achieves staged combustion of fuel.

[0067] The ignition device of the burner is arranged on the central axis of the burner. A swirl stabilizing plate 15 is arranged on the outside of the ignition gas gun sleeve 12 for stabilizing the central flame. The ignition gas gun 14 is fixed inside the ignition gas gun sleeve 12 by the tail flange 25 and can be disassembled for maintenance. The high-energy ignition gun 13 is arranged inside the sleeve of the ignition gas gun 14. The high-energy ignition gun 13 is fixed by a cylinder actuator. After ignition for 10 to 15 seconds, it retracts to a position 200 to 500 mm inside the inner tube 12 of the ignition gas gun. An ignition flame detection sleeve 23 is arranged in the swirl stabilizing plate 15 to realize the monitoring of the combustion flame during ignition.

[0068] The burner's air intake channels include a primary air channel, a secondary air channel, and a tertiary air channel. They adopt a concentric circular channel structure and the primary and secondary gas channels are arranged radially in a staggered manner to achieve multi-stage air stratification and reduce NOx emissions.

[0069] The primary air duct is formed by an annular air duct at the front end by the ignition gas gun sleeve 12 and the inner wall of the primary gas jacket 4, and then connected to the primary air duct 18. The primary air duct 18 is divided into a conical section and a straight section. A primary air regulating sleeve assembly 19 is arranged on the straight section. The air is supplied through multiple openings on the straight section of the primary air duct and enters the primary air duct. The primary air volume is changed by adjusting the front and rear positions of the primary air regulating sleeve.

[0070] The front end of the secondary air duct is formed by the outer wall of the primary gas jacket 4 and the inner wall of the secondary gas jacket 17 to form an annular air duct. The rear end of the secondary air duct is formed by the outer cylinder 5 and the rear insulation and sealing assembly 10 to form an air chamber. There are multiple air holes along the circumference at the rear end of the outer cylinder 5. The supplied air enters the secondary air duct and the primary air duct through the air holes respectively.

[0071] The front end of the tertiary air duct is formed by the outer wall of the secondary gas jacket 17 and the inner wall of the outer cylinder 5, creating an annular air duct. An annular partition 24 is welded to the rear end of the outer wall of the secondary gas jacket 17 to separate the secondary air duct and the tertiary air duct. A tertiary air regulating sleeve assembly 9 is arranged on the outer cylinder 5. Air is supplied through multiple tertiary air openings in the middle region of the outer cylinder 5 and enters the tertiary air duct. The tertiary air volume is changed by adjusting the front and rear positions of the tertiary air regulating sleeve.

[0072] The outer cylinder 5 is connected to the front end of the expansion cone 2. Two main flame detection sleeves 11 are arranged on the upper part of the expansion cone 2 for installing two main flame detection devices. The two-to-one control method is adopted to realize combustion monitoring.

[0073] The main air duct is circular in shape. It consists of a front insulation and sealing component 3, an outer cylinder 5, a rear insulation and sealing component 10, and a cylindrical sealing steel plate, forming a single burner main air chamber. An air inlet is designed on the cylindrical sealing steel plate, and the total air volume is remotely controlled by the main air damper.

[0074] The annular primary gas orifice plate 1 and the annular secondary gas orifice plate 16 have the same structure but different diameters and the number of gas holes. Both the annular primary gas orifice plate 1 and the annular secondary gas orifice plate 16 have an inner inclined surface 104 and an outer inclined surface 103 at the front end of the gas orifice plate, respectively. Inner gas nozzle holes 102 are evenly distributed circumferentially on the inner inclined surface 104 at the front end of the gas orifice plate, and outer gas nozzle holes 101 are evenly distributed circumferentially on the outer inclined surface 103 at the front end of the gas orifice plate. The axis of each gas nozzle hole is perpendicular to the inclined surface on which it is located, and each gas nozzle hole is an elliptical hole. The obtuse angle between the inner and outer inclined surfaces and the plane perpendicular to the burner axis is 150°. The gas nozzle holes are evenly distributed circumferentially on the gas orifice plate, and the inner gas nozzle holes 102 and the outer gas nozzle holes 101 are staggered circumferentially.

[0075] The primary gas connection pipes 6 are evenly arranged circumferentially on the primary gas header 7, and there are 6 of them. The secondary gas connection pipes 20 are evenly arranged circumferentially on the secondary gas header 21, and there are 6 of them. They are welded to the steel plate at the position of the rear insulation and sealing assembly 10 to provide support.

[0076] The primary gas header 7 is arranged inside the air duct and is an annular cylindrical header. The secondary gas header 21 is also arranged inside the air duct and is an annular cylindrical header.

[0077] The primary gas jacket 4 and the secondary gas jacket 17 are provided with gas nozzle holes evenly arranged on the inner and outer walls along the circumferential direction at their front ends, so as to realize partial premixed combustion of gas and air, which is conducive to complete combustion and reduction of NOx emissions.

[0078] Swirl blades are arranged at the front end of the secondary air duct and the front end of the tertiary air duct. The blades are installed at an angle of 50° to achieve swirling of the secondary and tertiary air, enhance the mixing of gas and air supply, and facilitate complete combustion.

[0079] Under oxygen-enriched conditions, the burner supplies a mixture of air and pure oxygen.

[0080] For other structures not specifically mentioned in this embodiment, please refer to Embodiment 1.

[0081] Example 3:

[0082] like Figures 1 to 4 As shown, the basic structure of the burner in this embodiment includes a primary gas passage and a secondary gas passage. The primary gas passage consists of an annular primary gas orifice plate 1 and a primary gas jacket 4 forming the inner and outer annular surfaces for gas injection. The primary gas jacket 4 is connected to a primary gas header 7 by multiple primary gas connecting pipes 6, and gas is ultimately introduced into the primary gas header 7 through a primary gas main pipe 8. The secondary gas passage consists of an annular secondary gas orifice plate 16 and a secondary gas jacket 17 forming the inner and outer annular surfaces for gas injection. The secondary gas jacket 17 is connected to a secondary gas header 21 by multiple secondary gas connecting pipes 20, and gas is ultimately introduced into the secondary gas header 21 through a secondary gas main pipe 22. This structure achieves staged combustion of fuel.

[0083] The ignition device of the burner is arranged on the central axis of the burner. A swirl stabilizing plate 15 is arranged on the outside of the ignition gas gun sleeve 12 for stabilizing the central flame. The ignition gas gun 14 is fixed inside the ignition gas gun sleeve 12 by the tail flange 25 and can be disassembled for maintenance. The high-energy ignition gun 13 is arranged inside the sleeve of the ignition gas gun 14. The high-energy ignition gun 13 is fixed by a cylinder actuator. After ignition for 10 to 15 seconds, it retracts to a position 200 to 500 mm inside the inner tube 12 of the ignition gas gun. An ignition flame detection sleeve 23 is arranged in the swirl stabilizing plate 15 to realize the monitoring of the combustion flame during ignition.

[0084] The burner's air intake channels include a primary air channel, a secondary air channel, and a tertiary air channel. They adopt a concentric circular channel structure and the primary and secondary gas channels are arranged radially in a staggered manner to achieve multi-stage air stratification and reduce NOx emissions.

[0085] The primary air duct is formed by an annular air duct at the front end by the ignition gas gun sleeve 12 and the inner wall of the primary gas jacket 4, and then connected to the primary air duct 18. The primary air duct 18 is divided into a conical section and a straight section. A primary air regulating sleeve assembly 19 is arranged on the straight section. The air is supplied through multiple openings on the straight section of the primary air duct and enters the primary air duct. The primary air volume is changed by adjusting the front and rear positions of the primary air regulating sleeve.

[0086] The front end of the secondary air duct is formed by the outer wall of the primary gas jacket 4 and the inner wall of the secondary gas jacket 17 to form an annular air duct. The rear end of the secondary air duct is formed by the outer cylinder 5 and the rear insulation and sealing assembly 10 to form an air chamber. There are multiple air holes along the circumference at the rear end of the outer cylinder 5. The supplied air enters the secondary air duct and the primary air duct through the air holes respectively.

[0087] The front end of the tertiary air duct is formed by the outer wall of the secondary gas jacket 17 and the inner wall of the outer cylinder 5, creating an annular air duct. An annular partition 24 is welded to the rear end of the outer wall of the secondary gas jacket 17 to separate the secondary air duct and the tertiary air duct. A tertiary air regulating sleeve assembly 9 is arranged on the outer cylinder 5. Air is supplied through multiple tertiary air openings in the middle region of the outer cylinder 5 and enters the tertiary air duct. The tertiary air volume is changed by adjusting the front and rear positions of the tertiary air regulating sleeve.

[0088] The outer cylinder 5 of the present invention is connected to the front end of the expansion cone 2. Two main flame detection sleeves 11 are arranged on the upper part of the expansion cone 2 for installing two main flame detection devices. The two-to-one control method is adopted to realize combustion monitoring.

[0089] The main air duct of the present invention has a square shape. The main air duct is composed of a front insulation and sealing component 3, an outer cylinder 5, a rear insulation and sealing component 10 and a sealing steel plate to form a single burner main air chamber. The total air volume is remotely controlled by the main air damper.

[0090] The annular primary gas orifice plate 1 of this invention is provided with internal gas nozzle holes 102 and external gas nozzle holes 101, both of which are small circular holes. The obtuse angle α between the outer inclined surface 103 at the front end of the gas orifice plate where the external gas nozzle hole 101 is located and the plane perpendicular to the burner axis is 140°. The obtuse angle α between the inner inclined surface 104 at the front end of the gas orifice plate where the internal gas nozzle hole 102 is located and the plane perpendicular to the burner axis is also 140°. The gas nozzle holes are evenly distributed circumferentially on the gas orifice plate, while the internal gas nozzle holes 102 and external gas nozzle holes 101 are staggered circumferentially. The axes of the gas nozzle holes are all perpendicular to the inclined surfaces.

[0091] The annular secondary gas orifice plate 16 is provided with slit-shaped nozzle holes. The gas nozzle holes are evenly distributed circumferentially on the gas orifice plate. The inner slit nozzle holes and the outer slit nozzle holes are arranged in a row. The angle between the length direction of the slit nozzle holes and the center line of the gas orifice plate is 60°.

[0092] The primary gas connection pipes 6 are evenly arranged circumferentially on the primary gas header 7, and there are 6 of them. The secondary gas connection pipes 20 are evenly arranged circumferentially on the secondary gas header 21, and there are 6 of them. They are welded to the steel plate at the position of the insulation component to provide support.

[0093] The primary gas header 7 is arranged inside the air duct and is a circular pipe annular header. The secondary gas header 21 is arranged outside the air duct and is a circular pipe annular header.

[0094] Swirl blades are arranged at the front end of the secondary air duct and the front end of the tertiary air duct. The blades are installed at an angle of 50° to achieve swirling of the secondary and tertiary air, enhance the mixing of gas and air supply, and facilitate complete combustion.

[0095] For other structures not specifically mentioned in this embodiment, please refer to Embodiment 1.

[0096] The burner supplies a mixture of air and flue gas, with the oxygen content preferably between 12% and 18%, thereby achieving flue gas recirculation technology to reduce NOx emissions.

[0097] Finally, it should be noted that the above is only used to illustrate the technical solution of the present invention and not to limit it. Although the present invention has been described in detail with reference to the preferred arrangement, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of the present invention, such as the number, shape, distribution mode of the nozzles, and the order of steps, without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A ring-shaped stratified flow gas low-NOx combustor, the combustor comprising a central ignition lance sleeve (12) for mounting an ignition device at the center thereof, an outer cylinder (5) arranged coaxially outside the ignition lance sleeve (12), a front heat preservation sealing assembly (3) arranged at the front end of the outer cylinder (5), and a rear heat preservation sealing assembly (10) arranged at the rear end of the outer cylinder (5), the air inlet channel of the combustor comprising a primary air channel and a secondary air channel and a tertiary air channel arranged at the periphery thereof, characterized in that: the ignition lance sleeve (12) is arranged outwardly with a primary gas channel and a secondary gas channel, the primary gas channel is composed of a ring-shaped primary gas orifice plate (1) and a primary gas jacket (4) at the front end of the gas channel, the primary gas jacket (4) is connected to a primary gas header (7) via a primary gas connecting pipe (6) to form a primary gas assembly; the secondary gas channel is composed of a ring-shaped secondary gas orifice plate (16) and a secondary gas jacket (17) at the front end of the gas channel, the secondary gas jacket (17) is connected to a secondary gas header (21) via a secondary gas connecting pipe (20) to form a secondary gas assembly; the ring-shaped primary gas orifice plate (1) and the ring-shaped secondary gas orifice plate (16) are formed with inwardly inclined inner gas nozzle holes (102) and outwardly inclined outer gas nozzle holes (101). the front end of the primary air channel is a ring-shaped air duct composed of the inner wall of the ignition lance sleeve (12) and the primary gas jacket (4); the front end of the secondary air channel is a ring-shaped air duct composed of the outer wall of the primary gas jacket (4) and the inner wall of the secondary gas jacket (17), and the front end of the tertiary air channel is a ring-shaped air duct composed of the outer wall of the secondary gas jacket (17) and the inner wall of the outer cylinder (5), and the ratio of the primary air, the secondary air and the tertiary air can be adjusted. the ring-shaped primary gas orifice plate (1) and the ring-shaped secondary gas orifice plate (16) are respectively formed with an inner inclined surface (104) at the front end of the gas orifice plate and an outer inclined surface (103) at the front end of the gas orifice plate, the inner gas nozzle holes (102) are uniformly distributed along the circumference on the inner inclined surface (104) at the front end of the gas orifice plate, and the outer gas nozzle holes (101) are uniformly distributed along the circumference on the outer inclined surface (103) at the front end of the gas orifice plate, the axis of each gas nozzle hole is perpendicular to the inclined surface, and the obtuse angle a between the inclined surface and the plane perpendicular to the axis of the combustor is 110°-170°.

2. The annularly-staged, premix gas low NOx combustor of claim 1 wherein: a central ring-shaped air duct is connected to a primary air pipe (18) to form a primary air channel, the primary air pipe (18) is divided into a tapered section and a straight section, the large-diameter end of the tapered section is connected to the rear end of the primary gas jacket (4), a plurality of primary air openings are uniformly arranged along the circumference on the straight section, a primary air adjusting sleeve assembly (19) is correspondingly arranged on the straight section, and the primary air volume can be changed by adjusting the front and rear positions of the primary air adjusting sleeve.

3. The annularly-staged, premix gas low NOx combustor according to claim 1 wherein: the rear end of the secondary air channel is composed of the outer cylinder (5) and the rear heat preservation sealing assembly (10) to form an air chamber, a plurality of air holes are arranged along the circumference at the rear end of the outer cylinder (5), and the air supplied by the combustor enters the secondary air channel and the primary air channel through the air holes, respectively.

4. The annularly-staged, premix gas low NOx combustor according to claim 3 wherein: ​ 5. The annularly-staged, premix gas low NOx combustor according to claim 4 wherein the An annular partition (24) is welded between the rear end of the outer wall of the secondary gas jacket (17) and the outer cylinder (5) to divide the secondary air passage and the tertiary air passage. The outer cylinder is provided with tertiary air holes in the middle part of the outer cylinder in the front end of the annular partition (24) and the tertiary air adjusting sleeve assembly (9) is arranged on the outer cylinder (5). The tertiary air amount is changed by adjusting the front and rear positions of the tertiary air adjusting sleeve.

6. The annularly-staged, premix gas low NOx combustor of claim 3, 4 or 5 wherein: The primary gas assembly, the primary air and the air adjusting assembly are connected as a whole and can be extracted as a whole from the rear of the burner. The secondary gas assembly, the tertiary air and the air adjusting assembly are connected as another whole and can be extracted as a whole from the rear of the burner.

7. The annularly-staged, premix gas low NOx combustor according to claim 1 wherein: The ignition device is arranged on the central axis of the burner. The ignition gas gun sleeve (12) is provided with a rotational flow stable combustion disc (15) outside for stable combustion of the central flame. The ignition gas gun (14) is fixedly arranged in the ignition gas gun sleeve (12) through the tail flange (25). The high-energy ignition gun (13) is arranged in the sleeve of the ignition gas gun (14). The high-energy ignition gun (13) is fixed by a gas cylinder actuator.

8. The annularly-staged, premix gas low NOx combustor according to claim 7 wherein: The rotational flow stable combustion disc (15) is provided with an ignition flame detection sleeve (23) for installing a flame detector. The outer cylinder (5) is connected with an expansion cone (2) at the front end. Two main flame detection sleeves (11) are arranged on the upper part of the expansion cone (2) for installing two main flame detection devices.

9. The annularly-shaped, stratified-flow gas low-NOx burner according to claim 1, characterized in that: The primary gas connecting pipes are uniformly arranged on the primary gas header along the circumference, and the number is between 5 and 20. The primary gas is introduced into the primary gas header by the primary gas main pipe. The secondary gas connecting pipes are uniformly arranged on the secondary gas header along the circumference, and the number is between 5 and 20. The secondary gas is introduced into the secondary gas header by the secondary gas main pipe.

10. The annularly-shaped, stratified-flow gas low-NOx burner according to claim 1, characterized in that: Gas nozzle holes are uniformly arranged on the inner and outer wall surfaces of the front end of the primary gas jacket and the secondary gas jacket.

11. The annularly-shaped, stratified-flow gas, low-NOx combustor according to claim 1, characterized by: The concentric annular passage structure of the burner is provided with N air passages, and N is a positive integer greater than 3. The secondary gas passage of the burner is correspondingly expanded outward by N-1 gas passages.

12. The annularly-shaped, stratified-flow gas, low-NOx combustor according to claim 1, characterized by: Rotational flow vanes are arranged at the front end of the secondary air passage and the front end of the tertiary air passage. The installation angle of the vanes is between 25° and 75°.

13. The annularly-shaped, stratified-flow gas, low-NOx combustor according to claim 1, characterized by: The air supply of the burner can be selected from air, mixed gas of air and flue gas, and mixed gas of pure oxygen and air. When the air and flue gas mixture is selected, the oxygen content of the air supply is between 12% and 18%.

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