A dual channel low-nitrogen flameless burner

Abstract

The application discloses a double-channel low-nitrogen flameless combustor and relates to the technical field of combustion devices. The combustor comprises a burner shell, the burner shell comprises a conventional mode gas cavity and a conventional mode air cavity, a conventional mode gas cyclone device is arranged at the outlet of the conventional mode gas cavity, a conventional mode air cyclone device is arranged at the outlet of the conventional mode air cavity, the burner shell further comprises a flameless mode gas cavity and a flameless mode air cavity, a flameless mode gas nozzle is arranged at the outlet of the flameless mode gas cavity, and a flameless mode air cyclone device is arranged at the outlet of the flameless mode air cavity. The combustor can be converted from flame combustion to flameless combustion. Compared with flame combustion, flameless combustion has the advantages of more uniform and stable combustion, high efficiency, low noise, uniform temperature distribution, reduction of high-temperature zones, inhibition of the generation of NOx, reduction of the possibility of damage of a combustion chamber caused by open fire baking, reduction of the maintenance cost of equipment and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of combustion devices, in particular to a double-channel low-nitrogen flameless burner. BACKGROUND

[0002] With the increasingly stringent national environmental protection policy on atmospheric pollutant emissions in recent years, the NOx emission standard is continuously improved. The existing burner usually mixes air and fuel gas through a swirl plate and then ignites directly to produce flame combustion in the furnace. However, the stability of flame combustion is poor, and the flame is easily disturbed by air flow, resulting in uneven temperature distribution, so it is difficult to control the temperature stability, and high-temperature zones are easily produced, resulting in more NOx and environmental pollution.

[0003] The swirl plate is a common swirl device, which is usually composed of a plurality of swirl plates inclined to the axis of the swirl plate.

[0004] The flameless combustion technology is a technology that sprays high-temperature air into the furnace to maintain a high-temperature and low-oxygen state in the furnace, and at the same time, the fuel is delivered to the furnace to produce combustion. Flameless combustion can effectively reduce the emission of nitrogen oxides and reduce combustion noise. SUMMARY

[0005] The purpose of the present application is to provide a double-channel low-nitrogen flameless burner, which can be converted from flame combustion to flameless combustion. Compared with flame combustion, flameless combustion has many advantages such as more uniform and stable combustion, high efficiency, low noise, uniform temperature distribution, reduction of high-temperature zones, inhibition of NOx generation, reduction of the possibility of damage to the combustion chamber by open fire baking, and reduction of equipment maintenance costs.

[0006] To solve the above technical problems, the present application adopts the following scheme:

[0007] A double-channel low-nitrogen flameless burner, comprising a burner shell, the burner shell comprising a conventional mode gas cavity and a conventional mode air cavity, a conventional mode gas swirl device is arranged at the outlet of the conventional mode gas cavity, a conventional mode air swirl device is arranged at the outlet of the conventional mode air cavity, the conventional mode gas swirl device is adjacent to the conventional mode air swirl device,

[0008] The burner shell further comprises a flameless mode gas cavity and a flameless mode air cavity, at least two flameless mode gas nozzles are arranged at the outlet of the flameless mode gas cavity and uniformly distributed around the axis of the flameless mode gas cavity, a flameless mode air swirl device is arranged at the outlet of the flameless mode air cavity, the flameless mode gas nozzle is adjacent to the flameless mode air swirl device,

[0009] An outlet section is arranged on the burner shell, the conventional mode gas swirl device, the conventional mode air swirl device,

[0010] The flameless mode air swirl device and the flameless mode gas nozzle are located on the outlet section, and the conventional mode gas cavity, the conventional mode air cavity, the flameless mode gas cavity and the flameless mode air cavity are isolated from each other. The flameless mode air swirl device and the flameless mode gas nozzle are located on the outlet section, and the conventional mode gas cavity, the conventional mode air cavity, the flameless mode gas cavity and the flameless mode air cavity are isolated from each other. The function is that, by designing the conventional mode gas swirl device, the conventional mode air swirl device, the flameless mode air swirl device and the flameless mode gas nozzle on the outlet section, the gas passing through the conventional mode gas swirl device and the air passing through the conventional mode air swirl device are mixed first to perform conventional flaming combustion, when the combustion temperature is high enough, the conventional mode air cavity and the conventional mode gas cavity are slowly closed, and the flameless mode air cavity and the flameless mode gas cavity are opened. The air-fuel ratio (the ratio of air to gas) of the flameless mode is much larger than the theoretical air-fuel ratio, and the large air excess coefficient is beneficial to realize flameless combustion, and the temperature in the furnace can also be controlled to prevent the furnace from overheating. Since the temperature at the outlet of the burner shell has reached the self-ignition temperature of the gas during flaming combustion, after the air passes through the flameless mode air cavity and the gas passes through the flameless mode gas cavity, and is premixed in the castable channel between the outlet of the burner shell and the furnace, the flameless combustion is formed in the furnace, which can effectively reduce the emission of nitrogen oxides and reduce the combustion noise.

[0011] Further, the conventional mode air cavity is sleeved outside the conventional mode gas cavity, the flameless mode gas cavity is sleeved outside the conventional mode air cavity, and the flameless mode air cavity is sleeved outside the flameless mode gas cavity. The function is that, by designing the space relationship between the conventional mode air cavity, the conventional mode gas cavity, the flameless mode air cavity and the flameless mode gas cavity, the outlet of the conventional mode air cavity can be surrounded on the outer contour of the outlet of the conventional mode gas cavity, which is convenient for the air and the gas to be fully mixed in the conventional mode, and the air and the gas can also be fully mixed in the flameless mode.

[0012] Further, the conventional mode air cavity, the conventional mode gas cavity, the flameless mode air cavity and the flameless mode gas cavity are all cylindrical and coaxially arranged. The function is that, by setting the shape of the conventional mode air cavity, the conventional mode gas cavity, the flameless mode air cavity and the flameless mode gas cavity and the further space relationship, and the existing swirl device (i.e. swirl plate) is disc-shaped or hollow disc-shaped, it is convenient to set the swirl device between different cavities.

[0013] Further, the conventional mode air cavity is communicated with a conventional mode air inlet pipe, and the conventional mode air inlet pipe is arranged along the radial direction of the conventional mode air cavity,

[0014] The conventional mode gas cavity is communicated with a conventional mode gas inlet pipe, and the conventional mode gas inlet pipe is arranged along the radial direction of the conventional mode gas cavity,

[0015] The flameless mode air cavity is connected with a flameless mode air inlet pipe, and the flameless mode air inlet pipe is arranged along the radial direction of the flameless mode air cavity,

[0016] The flameless mode gas cavity is connected with a flameless mode gas inlet pipe, and the flameless mode gas inlet pipe is arranged along the tangential direction of the flameless mode gas cavity,

[0017] The conventional mode air inlet pipe, the conventional mode gas inlet pipe, the flameless mode air inlet pipe and the flameless mode gas inlet pipe are arranged separately. Through the design of the spatial relationship between the conventional mode air inlet pipe and the conventional mode air cavity, the air can quickly enter the conventional mode air cavity through the conventional mode air inlet pipe, and the conventional mode gas inlet pipe and the flameless mode air inlet pipe are the same. Through the design of the arrangement of the flameless mode gas inlet pipe along the tangential direction of the flameless mode gas cavity, the gas entering the flameless mode gas cavity rotates along the inner wall of the flameless mode gas cavity, and the resistance is increased to make the air and gas in the flameless mode flow uniformly at each flameless mode gas nozzle, so as to ensure the power of each flameless mode gas nozzle as much as possible, so that the temperature distribution of the burner is uniform when it is in the flameless combustion state, the temperature change is stable, and the high-temperature area is not easy to produce, thereby reducing the production of NOx and avoiding pollution of the environment.

[0018] Further, the burner shell is connected with a refractory layer, the refractory layer is arranged outside the outlet section, the refractory layer is provided with a flame passage corresponding to the conventional mode air cyclone device and the conventional mode gas cyclone device and a plurality of nozzle passages uniformly distributed around the flame passage, the conventional mode air cyclone device, the conventional mode gas cyclone device and the flameless mode air cyclone device are located on the end face of the outlet section, and each nozzle passage is provided with a flameless mode gas nozzle. The refractory layer is made of refractory lightweight castable. Through the arrangement of the flame passage on the refractory layer, the heat and gas generated by the flame in the conventional mode can be transmitted to the furnace through the flame passage, so as to improve the temperature in the furnace and prepare for the flameless combustion; through the arrangement of the nozzle passage on the refractory layer, the gas and air in the flameless mode are mixed in the nozzle passage, and the possibility of backfire is reduced.

[0019] Further, the flameless mode gas nozzle is in the shape of a circular tube, the section of the flameless mode gas nozzle located in the nozzle passage is arranged in parallel with the axis of the flameless mode gas cavity, the outer wall of the section of the flameless mode gas nozzle located in the nozzle passage is uniformly provided with a plurality of gas nozzles in the circumferential direction, and the flameless mode air cyclone device is sleeved on the flameless mode gas nozzle at the junction of the burner shell and the refractory layer. The flameless mode air cyclone device adopts a cyclone plate. Through the spatial relationship between the flameless mode air cyclone device and the flameless mode gas nozzle and the design of the gas nozzles on the flameless mode gas nozzle, the gas and air in the flameless mode can be fully mixed.

[0020] Further, the burner shell is provided with an ignition burner, the ignition burner extends through the burner shell

[0021] to the end surface of the refractory layer facing away from the burner shell, and the ignition burner intersects the extension direction of the flame passage towards the outside of the burner shell in the extension direction of the ignition burner itself.

[0022] The burner shell is provided with a UV flame detection device, the UV flame detection device extends through the burner shell to the inner wall of the flame passage,

[0023] The ignition burner, the UV flame detection device and the thermocouple sensor all adopt existing technologies. Through the arrangement of the ignition burner, the gas mixed through the flame passage in the conventional mode can be ignited; through the arrangement of the UV flame detection device, the flame state in the flame passage in the conventional mode can be detected; and through the arrangement of the thermocouple sensor, the gas supply can be cut off when the temperature of the flameless mode air inlet pipe and / or the flameless mode gas inlet pipe is high, thereby preventing backfire.

[0024] Further, the inclination direction of the cyclone vane on the conventional mode gas cyclone device is opposite to the inclination direction of the cyclone vane on the conventional mode air cyclone device. This can make the gas rotation direction through the conventional mode gas cavity and the air rotation direction through the conventional mode air cavity opposite, thereby facilitating the full mixing of the gas and air in the conventional mode.

[0025] Further, the conventional mode air cyclone device comprises a tapered cylinder with gradually decreasing inner diameter towards the outlet of the conventional mode air cavity, the outer wall of the tapered cylinder is provided with outer ring cyclone vanes uniformly distributed in a ring shape around the axis of the tapered cylinder, the inner wall of the tapered cylinder is provided with inner ring cyclone vanes uniformly distributed in a ring shape around the axis of the tapered cylinder, and the inclination directions of the outer ring cyclone vanes and the inner ring cyclone vanes are the same. The thickness of the tapered cylinder is uniform. The tapered cylinder can increase the flow rate of the gas passing through the tapered cylinder, and the outer ring cyclone vanes and the inner ring cyclone vanes can make the conventional mode air cyclone device perform staged cyclone on the air in the conventional mode, so that the air in the conventional mode is mixed with the fuel gas in stages, the fuel gas is burned in stages at the flame passage, and the lean oxygen combustion state during the burning is beneficial to the suppression of NOx and the preparation for flameless combustion.

[0026] Further, the conventional mode air cavity is provided with a support ring for supporting the conventional mode fuel gas cavity, the support ring is provided with through holes for air to pass through, the flameless mode air cavity is provided with flameless mode air cyclone vanes uniformly surrounding the outer wall of the flameless mode fuel gas cavity, and the sidewall of the flameless mode fuel gas cavity between the flameless mode air cyclone vanes and the outlet is provided with a fuel gas port for communicating with the flameless mode fuel gas nozzle. The support ring can support the conventional mode fuel gas cavity, the flameless mode air cyclone vanes can make the fuel gas enter the flameless mode fuel gas cavity and flow along the inner wall of the flameless mode fuel gas cavity before cyclone, and the resistance can be increased to make the air and the fuel gas in the flameless mode uniformly flow at each flameless mode fuel gas nozzle, so that the power of each flameless mode fuel gas nozzle is consistent, the temperature distribution of the burner is uniform when the burner is in the flameless combustion state, the temperature change is stable, a high-temperature zone is not easy to produce, the production of NOx is reduced, and the environment is protected.

[0027] Further, the conventional mode air cavity is provided with a support ring for supporting the conventional mode fuel gas cavity, the support ring is provided with through holes for air to pass through, the flameless mode air cavity is provided with flameless mode air cyclone vanes uniformly surrounding the outer wall of the flameless mode fuel gas cavity, and the sidewall of the flameless mode fuel gas cavity between the flameless mode air cyclone vanes and the outlet is provided with a fuel gas port for communicating with the flameless mode fuel gas nozzle. The support ring can support the conventional mode fuel gas cavity, the flameless mode air cyclone vanes can make the fuel gas enter the flameless mode fuel gas cavity and flow along the inner wall of the flameless mode fuel gas cavity before cyclone, and the resistance can be increased to make the air and the fuel gas in the flameless mode uniformly flow at each flameless mode fuel gas nozzle, so that the power of each flameless mode fuel gas nozzle is consistent, the temperature distribution of the burner is uniform when the burner is in the flameless combustion state, the temperature change is stable, a high-temperature zone is not easy to produce, the production of NOx is reduced, and the environment is protected.

[0028] The present application has the following beneficial effects:

[0029] 1. The use of double-channel mode realizes flameless low-nitrogen combustion, and the conventional mode is switched to the flameless low-nitrogen mode after the temperature in the furnace is increased to the self-ignition temperature of the combustible gas, which reduces the equipment investment cost compared with the traditional use of high-speed injection of high-temperature preheated air, and the system is more simplified;

[0030] 2. The thermocouple sensor arranged at the air and fuel gas inlets in the flameless mode can detect whether backfire occurs in the burner in the flameless mode, and the system safety of the flameless combustion process is improved;

[0031] 3. This burner uses a staged swirling device consisting of a conical cylinder, an outer ring swirl vane, and an inner ring swirl vane in the conventional mode air chamber. In the conventional mode flame channel, some air is first mixed into the combustion gas and then some air is mixed in at the rear, so that the combustion gas is burned in stages and segments in front of the burner nozzle. When the combustion zone is in the "oxygen-deficient combustion" state, it has a good effect on suppressing NOx production.

[0032] 4. The flameless mode gas in this burner adopts tangential air intake through the cylinder. Tangential air intake allows the gas to enter the flameless mode air chamber and rotate forward. If the size and resistance of the flameless mode air chamber are appropriate, the uniformity error of the gas volume of each flameless nozzle can be achieved with no more than 1%, which greatly improves the temperature uniformity. Attached Figure Description

[0033] Figure 1 is a schematic diagram of the front view structure of Embodiment 1;

[0034] Figure 2 is a schematic diagram of the right-side structure of Embodiment 1;

[0035] Figure 3 is a schematic diagram of the rear view structure of Embodiment 1;

[0036] Figure 4 is a schematic cross-sectional view of the structure at point AA in Figure 1;

[0037] Figure 5 is a schematic cross-sectional view of the structure at BB in Figure 1;

[0038] Figure 6 is Figure 2 A schematic diagram of the cross-sectional flow channel structure at point CC;

[0039] Figure 7 is a schematic front view of the conventional mode air swirl device in Example 1;

[0040] Figure 8 is a schematic cross-sectional view of the structure at DD in Figure 7;

[0041] Figure 9 is a top view of the combustion chamber in the flameless mode of Example 1;

[0042] Figure 10 shows the experimental data of fluid simulation of the flameless mode gas chamber.

[0043] Reference numerals: 1. Burner shell; 2. Conventional mode gas chamber; 3. Conventional mode air chamber; 4. Conventional mode gas swirl device; 5. Conventional mode air swirl device; 6. Flameless mode gas chamber; 7. Flameless mode air chamber; 8. Flameless mode air swirl device; 9. Flameless mode gas nozzle; 10. Outlet section; 11. Conventional mode air inlet pipe; 12. Conventional mode gas inlet pipe; 13. Flameless mode air inlet pipe; 14. Flameless mode gas inlet pipe; 15. Refractory layer; 16. Flame channel; 17. Nozzle channel; 18. Gas nozzle; 19. Support ring; 20. Ignition burner; 21. UV flame detection device; 22. Thermocouple sensor; 23. Conical cylinder; 24. Outer ring swirl vane; 25. Inner ring swirl vane; 26. Flameless mode air swirl vane; 27. Gas port. Detailed Implementation

[0044] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0045] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "longitudinal," "lateral," "horizontal," "inner," "outer," "front," "rear," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0046] In the description of this invention, it should be noted that the term "multiple" indicates a quantity of at least two, and any number of such quantities can be used to achieve the basic functions of the structure.

[0047] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "have," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0048] Example 1

[0049] A dual-channel low-NOx flameless burner, as shown in Figure 1- Figure 5 As shown, it includes a burner housing 1, the burner

[0050] The shell 1 includes a conventional mode gas cavity 2 and a conventional mode air cavity 3, the outlet of the conventional mode gas cavity 2 is provided with a conventional mode gas cyclone device 4, the outlet of the conventional mode air cavity 3 is provided with a conventional mode air cyclone device 5, the conventional mode gas cyclone device 4 is adjacent to the conventional mode air cyclone device 5,

[0051] The burner shell 1 further includes an flameless mode gas cavity 6 and a flameless mode air cavity 7, the outlet of the flameless mode gas cavity 6 is provided with eight flameless mode gas nozzles 9 which are uniformly distributed around the axis of the flameless mode gas cavity 6, the outlet of the flameless mode air cavity 7 is provided with a flameless mode air cyclone device 8, the flameless mode gas nozzles 9 are adjacent to the flameless mode air cyclone device 8,

[0052] The burner shell 1 is provided with an outlet section 10, the conventional mode gas cyclone device 4, the conventional mode air cyclone device 5, the flameless mode air cyclone device 8 and the flameless mode gas nozzles 9 are all located on the outlet section 10, the conventional mode gas cavity 2, the conventional mode air cavity 3, the flameless mode gas cavity 6 and the flameless mode air cavity 7 are isolated from each other. The conventional mode gas cyclone device 4 adopts the existing disc-shaped cyclone plate, the central end face of the cyclone plate is uniformly distributed with gas holes for the gas to pass through; the conventional mode air cyclone device 5 adopts a circular ring-shaped staged cyclone device, the staged cyclone device is sleeved outside the conventional mode gas cyclone device 4; the flameless mode air cyclone device 8 adopts the existing circular ring-shaped cyclone plate, the cyclone plate is sleeved on the outer wall of the flameless mode gas nozzle 9. The installation mode of each cyclone device can be realized by using the existing technology, so it is not described again. Its function is that, by designing the conventional mode gas cyclone device 4, the conventional mode air cyclone device 5, the flameless mode air cyclone device 8 and the flameless mode gas nozzles 9 to be located on the outlet section 10, the gas passing through the conventional mode gas cyclone device 4 and the air passing through the conventional mode air cyclone device 5 are mixed first to perform the conventional flame combustion, when the combustion temperature is high enough, the conventional mode air cavity 3 and the conventional mode gas cavity 2 are slowly closed, and the flameless mode air cavity 7 and the flameless mode gas cavity 6 are opened, because the temperature at the outlet of the burner shell 1 has reached the self-ignition temperature of the gas during the flame combustion, therefore, under the condition of excessive air, the gas mixed through the flameless mode air cavity 7 and the flameless mode gas cavity 6 enters into the hearth from the outlet of the burner shell 1 to produce the flameless combustion, which can effectively reduce the emission of nitrogen oxides and reduce the combustion noise.

[0053] Specifically, as shown in FIG. 5, the conventional mode air cavity 3 is sleeved outside the conventional mode gas cavity 2, the flameless mode gas cavity 6 is sleeved outside the conventional mode air cavity 3, and the flameless mode air cavity 7 is sleeved outside the flameless mode gas cavity 6. Through the design of the spatial relationship among the conventional mode air cavity 3, the conventional mode gas cavity 2, the flameless mode air cavity 7, and the flameless mode gas cavity 6, the outlet of the conventional mode air cavity 3 can be wrapped around the outer contour of the outlet of the conventional mode gas cavity 2,

[0054] The air and the gas can be fully mixed in the conventional mode, and the air and the gas can be fully mixed in the flameless mode.

[0055] Specifically, as shown in FIG. 1 and FIG. 5, the conventional mode air cavity 3, the conventional mode gas cavity 2, the flameless mode air cavity 7, and the flameless mode gas cavity 6 are all in a cylindrical shape and are coaxially arranged. That is, the inner diameter of the conventional mode air cavity 3 is greater than the outer diameter of the conventional mode gas cavity 2, the inner diameter of the flameless mode gas cavity 6 is greater than the outer diameter of the conventional mode air cavity 3, and the inner diameter of the flameless mode air cavity 7 is greater than the outer diameter of the flameless mode gas cavity 6. Through the shape and further spatial relationship of the conventional mode air cavity 3, the conventional mode gas cavity 2, the flameless mode air cavity 7, and the flameless mode gas cavity 6, and the existing cyclone device (i.e., the cyclone plate) is in a disc shape or a hollow disc shape, it is convenient to arrange the cyclone device between different cavities.

[0056] Specifically, as shown in FIG. 2 and FIG. 5, the conventional mode air cavity 3 is connected with the conventional mode air inlet pipe 11, and the conventional mode air inlet pipe 11 is arranged along the radial direction of the conventional mode air cavity 3,

[0057] The conventional mode gas cavity 2 is connected with the conventional mode gas inlet pipe 12, and the conventional mode gas inlet pipe 12 is arranged along the radial direction of the conventional mode gas inlet pipe 12,

[0058] The flameless mode air cavity 7 is connected with the flameless mode air inlet pipe 13, and the flameless mode air inlet pipe 13 is arranged along the radial direction of the flameless mode air cavity 7,

[0059] As shown in FIG. 6, the flameless mode gas cavity 6 is connected with the flameless mode gas inlet pipe 14, and the flameless mode gas inlet pipe 14 is arranged along the tangential direction of the flameless mode gas cavity 6,

[0060] The conventional mode air inlet pipe 11, the conventional mode gas inlet pipe 12, the flameless mode air inlet pipe 13 and the flameless mode gas inlet pipe 14 are arranged separately from each other. The outlets of the conventional mode air cavity 3, the conventional mode gas cavity 2, the flameless mode air cavity 7 and the flameless mode gas cavity 6 are located on the same plane, the length of the flameless mode gas cavity 6 is greater than the length of the flameless mode air cavity 7, the length of the conventional mode air cavity 3 is greater than the length of the flameless mode gas cavity 6, the length of the conventional mode gas cavity 2 is opposite to the length of the conventional mode gas cavity 2, the conventional mode air inlet pipe 11 and the conventional mode gas inlet pipe 12 are located on the burner shell 1 away from the outlet section 10, the conventional mode air inlet pipe 11 and the conventional mode gas inlet pipe 12 are arranged in opposite directions and coaxially, the conventional mode air inlet pipe 11 is arranged on the conventional mode air cavity 3 outside the flameless mode gas cavity 6, the conventional mode gas inlet pipe 12 penetrates the conventional mode air cavity 3 and is arranged on the conventional mode gas cavity 2 outside the flameless mode gas cavity 6, and the flameless mode gas inlet pipe 14 is arranged on the flameless mode gas cavity 6 outside the flameless mode air cavity 7. The function is,

[0061] Through the design of the spatial relationship between the conventional mode air inlet pipe 11 and the conventional mode air cavity 3, the air can quickly enter the conventional mode air cavity 3 through the conventional mode air inlet pipe 11, and the conventional mode gas inlet pipe 12 and the flameless mode air inlet pipe 13 are the same; through the design of the tangential arrangement of the flameless mode gas inlet pipe 14 along the flameless mode gas cavity 6, the gas entering the flameless mode gas cavity 6 rotates along the inner wall of the flameless mode gas cavity 6, and at the same time, the resistance can be increased to make the air and gas in the flameless mode evenly distributed at each flameless mode gas nozzle 9, so as to ensure the power of each flameless mode gas nozzle 9 as much as possible, so that the temperature distribution of the burner is uniform when it is in the flameless combustion state, the temperature change is relatively stable, and high temperature area is not easy to produce, thereby reducing the production of NOx and avoiding pollution of the environment.

[0062] Specifically, as shown in FIG. 3, FIG. 4, and FIG. 5, the burner shell 1 is connected with a refractory layer 15, the refractory layer 15 is arranged outside the outlet section 10, the refractory layer 15 is provided with flame channels 16 corresponding to the conventional mode air swirl device 5 and the conventional mode gas swirl device 4 and eight jet channel 17 uniformly distributed in a ring around the flame channels 16, the conventional mode air swirl device 5, the conventional mode gas swirl device 4 and the flameless mode air swirl device 8 are located on the end face of the outlet section 10, and each jet channel 17 is provided with a flameless mode gas jet 9. The refractory layer 15 adopts a refractory lightweight castable. The flame channels 16 and the jet channel 17 are both cylindrical, the flameless mode gas jet 9 extends out of the burner shell 1 and is located in the jet channel 17, and the thickness of the refractory layer 15 is greater than the length of the flameless mode gas jet 9 extending out of the burner shell 1. The flame channels 16 on the refractory layer 15 can make the heat and gas generated by the flame burning in the conventional mode transmitted to the furnace through the flame channels 16, thereby improving the temperature in the furnace and preparing for the flameless combustion; the jet channel 17 on the refractory layer 15 can make the gas and air in the flameless mode mixed in the jet channel 17, thereby reducing the possibility of backfire.

[0063] Specifically, as shown in FIG. 4, the flameless mode gas jet 9 is in a circular tube shape, the section of the flameless mode gas jet 9 located in the jet channel 17 is arranged in parallel with the axis of the flameless mode gas cavity 6 and coaxially arranged with the jet channel 17, and a plurality of gas nozzles 18 are uniformly distributed on the outer wall of the section of the flameless mode gas jet 9 located in the jet channel 17 in the circumferential direction, and the flameless mode air swirl device 8 is sleeved on the flameless mode gas jet 9 at the junction of the burner shell 1 and the refractory layer 15. The flameless mode air swirl device 8 adopts a swirl plate. The space relationship between the flameless mode air swirl device 8 and the flameless mode gas jet 9 and the design of the gas nozzles 18 on the flameless mode gas jet 9 can make the gas and air in the flameless mode fully mixed.

[0064] Specifically, as shown in FIG. 3 and FIG. 5, the burner shell 1 is provided with an ignition burner 20, the ignition burner 20 extends to the end face of the refractory layer 15 away from the burner shell 1 through the burner shell 1, and the ignition burner 20 intersects with the extension direction of the flame channels 16 towards the outside of the burner shell 1 in the extension direction of the ignition burner 20.

[0065] The burner shell 1 is provided with a UV flame detection device 21, which extends to the inner wall of the flame passage 16 through the burner shell 1,

[0066] The flameless mode air inlet pipe 13 and the flameless mode gas inlet pipe 14 are each provided with a thermocouple sensor 22. The ignition burner 20, the UV flame detection device 21, and the thermocouple sensor 22 all adopt prior art. Through the setting of the ignition burner 20, the gas mixed in the conventional mode through the flame passage 16 can be ignited; through the setting of the UV flame detection device 21, the flame state in the flame passage 16 in the conventional mode can be detected; through the setting of the thermocouple sensor 22, the gas supply can be cut off when the temperature of the flameless mode air inlet pipe 13 and / or the flameless mode gas inlet pipe 14 is high, preventing backfire.

[0067] Specifically, as shown in FIG. 3, the inclination direction of the swirl vanes on the conventional mode gas swirl device 4 is opposite to the inclination direction of the swirl vanes on the conventional mode air swirl device 5. Its role is to make the gas swirl direction through the conventional mode gas cavity 2 and the air cavity swirl direction through the conventional mode air cavity 3 opposite, facilitating the full mixing of gas and air in the conventional mode.

[0068] Specifically, as shown in FIG. 7 and FIG. 8, the conventional mode air swirl device 5 includes a tapered cylinder 23 with a gradually decreasing inner diameter in the direction towards the outlet of the conventional mode air cavity 3, the outer wall of the tapered cylinder 23 is provided with outer ring swirl vanes 24 uniformly distributed in a ring shape around the axis of the tapered cylinder 23, the inner wall of the tapered cylinder 23 is provided with inner ring swirl vanes 25 uniformly distributed in a ring shape around the axis of the tapered cylinder 23, and the inclination directions of the outer ring swirl vanes 24 and the inner ring swirl vanes 25 are the same. In the front view of the conventional mode air swirl device 5, the inclination angles of the outer ring swirl vanes 24 and the inner ring swirl vanes 25 with the axis of the tapered cylinder 23 are both 45°. The thickness of the tapered cylinder 23 is the same everywhere. Its role is that through the setting of the tapered cylinder 23, the flow rate of the gas passing through the inside of the tapered cylinder 23 can be increased; through the design of the outer ring swirl vanes 24 and the inner ring swirl vanes 25, the conventional mode air swirl device 5 can perform staged swirl on air in the conventional mode, so that air and gas in the conventional mode are mixed in stages, and gas is burned in stages at the flame passage 16, which is beneficial to the preparation of NOx suppression and flameless combustion when burning in a lean oxygen combustion state.

[0069] Specifically, as shown in FIG. 5, the conventional mode air cavity 3 is provided with a support ring 19 for supporting the conventional mode gas cavity 2, and the support ring 19 is provided with through holes for air to pass through, as shown in Figure 9 FIG. 6, the flameless mode air cavity 7 is provided with a flameless mode air cyclone vane 26 uniformly surrounding the outer wall of the flameless mode gas cavity 6.

[0070] The flameless mode gas cavity 6 is provided with a gas port 27 on the side wall between the flameless mode air cyclone vane 26 and the outlet for communicating with the flameless mode gas nozzle 9. In the top view of the flameless mode gas cavity 6, the angle between the flameless mode air cyclone vane 26 and the axis of the flameless mode gas cavity 6 is 60°. The support ring 19 can support the conventional mode gas cavity 2, and the flameless mode air cyclone vane 26 can make the gas rotate along the inner wall of the flameless mode gas cavity 6 after entering the flameless mode gas cavity 6, and can also increase the resistance to make the air and gas in the flameless mode uniformly distributed at each flameless mode gas nozzle 9, so as to ensure the power of each flameless mode gas nozzle 9 as uniform as possible, so that the temperature distribution of the burner is uniform when it is in the flameless combustion state, the temperature change is stable, and high temperature area is not easy to produce, thereby reducing the production of NOx and avoiding environmental pollution.

[0071] The working principle of the embodiment is as follows: the double-channel low-nitrogen flameless burner is installed on an industrial furnace. When in use, the ignition burner 20 (the ignition burner 20 is installed on the side of the main burner, and the ignition burner 20 forms a flame in the inner chamber of the castable to provide a fire source for the burner shell 1) is first ignited. After the ignition burner 20 is stably combusted, the automatic control system (the automatic control system can be realized by using the existing technology) is switched to the conventional mode, the conventional mode gas channel is opened, the fuel gas enters the conventional mode gas cavity 2 through the conventional mode gas inlet pipe 12, the air enters the conventional mode air cavity 3 through the conventional mode air inlet pipe 11, the fuel gas and the air are mixed according to the air-fuel ratio, and the mixture is ignited under the fire source of the ignition burner 20 after being strongly and reversely rotated and fully mixed by the conventional mode air cyclone device 5 and the conventional mode fuel gas cyclone device 4. The flame state is detected by the UV flame detection device 21 on the burner shell 1, the valve opening of the gas inlet is gradually increased, the power of the conventional mode is increased to the maximum power, and the temperature in the furnace is rapidly increased after the conventional mode is opened. When the average temperature of the temperature sensors reaches 800 DEG C, the conventional mode gas channel is slowly closed (at this temperature, the commonly used combustible gas has reached the self-ignition temperature), the automatic control system is slowly switched to the flameless mode, the flameless mode gas channel is opened, and the air and the fuel gas can be uniformly sprayed from the eight jet channels 17 through the set cyclone device (as shown in FIG. 10, the flameless mode air cyclone piece 26 and the tangential type flameless mode air inlet pipe 13). If the size and resistance of the flameless mode air cavity 7 are appropriate, the fuel gas amount of each flameless jet can be uniformly distributed with an error of not more than 1%, and the temperature uniformity is greatly improved.

[0072] The air and the fuel gas are fully premixed in the eight jet channels 17 (outside the burner shell 1, the refractory layer 15, and the mixing in this place can reduce the possibility of backfire) and then enter the furnace. The premixed air and fuel gas can improve the reaction speed and reduce the residence time of excess oxygen in the air in the high-temperature zone, thereby reducing the generation of thermal NOx. Since the temperature in the furnace has reached the self-ignition temperature of the fuel gas, the premixed air and fuel gas can be fully reacted in the furnace under the condition of a large excess air ratio, thereby realizing flameless combustion. The air amount in the flameless mode is much larger than the theoretical air amount, and a part of the air is used for controlling the temperature in the furnace. The thermocouple sensor 22 is arranged at the air and fuel gas inlet in the flameless mode, and the burner can be cut off when the detected temperature is high to prevent backfire.

[0073] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. According to the technical essence of the present application, any simple modification, equivalent replacement and improvement of the above embodiment within the spirit and principle of the present application are still within the protection scope of the technical solution of the present application.

Claims

1. A dual pass low-nitrogen non-flaming burner characterized by: The device includes a burner housing (1), which includes a conventional mode gas chamber (2) and a conventional mode air chamber (3). A conventional mode gas swirling device (4) is provided at the outlet of the conventional mode gas chamber (2), and a conventional mode air swirling device (5) is provided at the outlet of the conventional mode air chamber (3). The conventional mode gas swirling device (4) is adjacent to the conventional mode air swirling device (5). The burner housing (1) also includes a flameless mode gas chamber (6) and a flameless mode air chamber (7). A flameless mode gas nozzle (9) is provided at the outlet of the flameless mode gas chamber (6), and a flameless mode air swirl device (8) is provided at the outlet of the flameless mode air chamber (7). The flameless mode gas nozzle (9) is adjacent to the flameless mode air swirl device (8). An outlet section (10) is provided on the burner housing (1). The conventional mode gas swirl device (4), the conventional mode air swirl device (5), the flameless mode air swirl device (8), and the flameless mode gas nozzle (9) are all located on the outlet section (10). The conventional mode gas chamber (2), the conventional mode air chamber (3), the flameless mode gas chamber (6), and the flameless mode air chamber (7) are isolated from each other. The conventional mode air cavity (3) is fitted outside the conventional mode gas cavity (2), the flameless mode gas cavity (6) is fitted outside the conventional mode air cavity (3), and the flameless mode air cavity (7) is fitted outside the flameless mode gas cavity (6). The conventional mode air chamber (3), the conventional mode gas chamber (2), the flameless mode air chamber (7), and the flameless mode gas chamber (6) are all cylindrical and coaxially arranged. The conventional mode air cavity (3) is connected to a conventional mode air inlet pipe (11), which is arranged radially along the conventional mode air cavity (3). The conventional mode gas chamber (2) is connected to a conventional mode gas inlet pipe (12), which is arranged radially along the conventional mode gas chamber (2). The flameless mode air cavity (7) is connected to a flameless mode air inlet pipe (13), which is arranged radially along the flameless mode air cavity (7). A flameless mode gas inlet pipe (14) is connected to the flameless mode gas chamber (6), and the flameless mode gas inlet pipe (14) is arranged tangentially to the flameless mode gas chamber (6). The air inlet pipe (11) in normal mode, the gas inlet pipe (12) in normal mode, and the air inlet pipe (13) in flameless mode and the gas inlet pipe (14) in flameless mode are set separately from each other; The burner shell (1) is connected with a refractory layer (15), the refractory layer (15) is arranged outside the outlet section (10), the refractory layer (15) is provided with flame channels (16) corresponding to the conventional mode air swirl device (5) and the conventional mode gas swirl device (4) and a plurality of nozzle channels (17) uniformly distributed in a ring around the flame channels (16), the conventional mode air swirl device (5), the conventional mode gas swirl device (4) and the flameless mode air swirl device (8) are located on the end face of the outlet section (10), and each nozzle channel (17) is provided with a flameless mode gas nozzle (9).

2. The dual pass low NO flameless combustor of claim 1, wherein: The flameless mode gas nozzle (9) is in the shape of a circular tube, the section of the flameless mode gas nozzle (9) in the nozzle channel (17) is arranged in parallel with the axis of the flameless mode gas cavity (6), and a plurality of gas nozzles (18) are uniformly distributed in the circumferential direction on the outer wall of the section of the flameless mode gas nozzle (9) in the nozzle channel (17).

3. The dual pass low NO flameless combustor of claim 1, wherein: The burner shell (1) is provided with an ignition burner (20), the ignition burner (20) extends through the burner shell (1) to the end face of the refractory layer (15) away from the burner shell (1), The burner shell (1) is provided with a UV flame detection device (21), the UV flame detection device (21) extends through the burner shell (1) to the inner wall of the flame channel (16), The flameless mode air inlet pipe (13) and the flameless mode gas inlet pipe (14) are each provided with a thermocouple sensor (22).

4. The dual pass low NO flameless combustor of claim 1, wherein: The inclination direction of the swirl vanes on the conventional mode gas swirl device (4) is opposite to the inclination direction of the swirl vanes on the conventional mode air swirl device (5).

5. The dual pass low NO flameless combustor of claim 4, wherein: The conventional mode air swirl device (5) comprises a conical cylinder (23) with a gradually decreasing inner diameter in the direction towards the outlet of the conventional mode air cavity (3), the outer wall of the conical cylinder (23) is provided with outer ring swirl vanes (24) uniformly distributed in a ring around the axis of the conical cylinder (23), the inner wall of the conical cylinder (23) is provided with inner ring swirl vanes (25) uniformly distributed in a ring around the axis of the conical cylinder (23), and the inclination directions of the outer ring swirl vanes (24) and the inner ring swirl vanes (25) are the same. The conventional mode air cavity (3) is provided with a support ring (19) for supporting the conventional mode gas cavity (2), the support ring (19) is provided with through holes for air to pass through, the flameless mode air cavity (7) is provided with flameless mode air swirl vanes (26) uniformly arranged on the outer wall of the flameless mode gas cavity (6), and the sidewall of the flameless mode gas cavity (6) between the flameless mode air swirl vanes (26) and the outlet is provided with a gas port (27) for communicating with the flameless mode gas nozzle (9).

6. The dual pass low NO flameless combustor of claim 1, wherein: ​

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