Low-emission high-speed burner, flameless combustion device and ignition method thereof

Abstract

Low-emission high-speed burner, flameless combustion device and ignition method thereof; by respectively arranging a primary axial air inlet inside the flame stabilizer and a secondary axial air inlet outside the flame stabilizer in the low-emission high-speed burner, the air flow conveyed by the air conveying channel enters the flame stabilizer in multiple paths to perform staged combustion with the air-fuel premixed gas flow discharged from the air-fuel premixer, better inhibiting the generation of NOx; moreover, the premixed flame burns rapidly in the flame tube with a contracted flame nozzle, and the high temperature causes the gas to expand, generating a certain back pressure inside the flame tube. This back pressure drives the flame to be ejected at high speed from the flame nozzle, thereby strengthening the in-furnace flue gas recirculation combustion and inhibiting the generation of NOx and CO, enabling the gas fuel to burn sufficiently and reducing the emissions of nitrogen oxides and combustion particulate matter, with good use effects.

Description

Technical Field

[0001] The present invention belongs to the technical field of burners, and particularly relates to a low-emission high-speed burner, a flameless combustion device and an ignition method thereof. Background Art

[0002] Industrial heating furnaces for high-temperature heating and melting applications, such as melting furnaces, industrial heating or heat treatment kilns, and ceramic kilns, often have corresponding requirements for the flame speed of burners due to process requirements. The traditional high-speed burner has a simple gas-air premixing structure setting method, and there are many deficiencies. For example, the gas fuel burns incompletely, the gas regulation ratio is low, the flame stability performance is poor, and the emissions of nitrogen oxides and combustion particulate matter are relatively high. Summary of the Invention

[0003] An object of the present invention is to overcome the problems of incomplete fuel combustion, high emissions of nitrogen oxides and combustion particulate matter existing in the existing burners, and provide a low-emission high-speed burner that increases the flame speed and realizes low emissions of nitrogen oxides and combustion particles through staged gas combustion.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] The low-emission high-speed burner includes: a burner body, a gas input device, an air-fuel premixer, a flame stabilizer and a flame tube.

[0006] The burner body is provided with a gas conduit located inside, an air delivery channel and an air inlet communicating with the air delivery channel. The air delivery channel is arranged around the outside of the gas conduit along the axial direction.

[0007] The gas input device is connected to the upstream end of the gas conduit and is provided with a gas inlet communicating with the gas conduit.

[0008] The air-fuel premixer is provided with an air-fuel premixing chamber respectively communicating with the gas conduit and the air delivery channel, and a main premixed gas injection port communicating with the air-fuel premixing chamber.

[0009] The flame stabilizer is provided with a flame stabilization chamber communicating with the main premixed gas injection port, a plurality of primary axial air inlets communicating with the flame stabilization chamber, a plurality of secondary axial air inlets located outside the flame stabilizer and communicating with the air delivery channel, and a premixed flame injection port having a plurality of lobe-shaped structures in the circumferential direction at the downstream end of the flame stabilizer. The secondary axial air inlets are located between adjacent lobe-shaped structures.

[0010] The flame tube is located at the downstream end of the burner body and is provided with a flame injection port with a gradually narrowing diameter communicating with the flame stabilization chamber.

[0011] Compared with the prior art, in the low-emission high-speed burner of the present invention, by respectively arranging a primary axial air inlet inside the flame stabilizer and a secondary axial air inlet outside the flame stabilizer, the air flow conveyed by the air delivery channel enters the flame stabilizer in multiple paths to perform staged combustion with the air-fuel premixed gas flow discharged from the air-fuel premixer. Its full combustion reaction better inhibits the generation of NOx; the secondary axial air inlet is arranged between adjacent lobe-shaped structures, strengthening the effective mixing of the air flow generated by it and the premixed flame generated by the premixed flame nozzle. At the same time, multiple relatively complex premixed flame vortex airflows will be formed between the outlet of the lobe structure and the lip of the premixed flame nozzle, becoming a reliable flame stabilizing structure for the secondary combustion of the premixed flame, and the premixed flame vortex airflow forms a conical expanding flame under the action of centrifugal force, better mixing and burning further with the air ejected from the secondary axial air inlet. Moreover, the premixed flame burns rapidly in the flame tube with a constricted flame nozzle. The high temperature causes the gas to expand, generating a certain back pressure inside the flame tube. This back pressure drives the flame to be ejected at high speed from the flame nozzle, thus strengthening the in-furnace flue gas recirculation combustion and inhibiting the generation of NOx and CO, enabling the gas fuel to burn sufficiently and reducing the emissions of nitrogen oxides and combustion particulate matter, with good use effects.

[0012] Further, the flame nozzle is a butterfly-shaped nozzle with a flat middle part and the diameters of the adjacent two sides increasing outward; by such an arrangement, by adjusting the gas flow distribution in the length direction of the nozzle, a more uniform flat flame can be obtained, enabling the flame to have better heating performance. At the same time, due to having a larger contact surface area with the furnace gas, the entrainment and suction capacity of the flame can be improved, and the furnace gas can dissipate heat faster, with a stronger ability to inhibit the generation of NOx.

[0013] Further, the flame stabilizer is also provided with a plurality of radial air inlets and a plurality of tangential air inlets communicating with the flame stabilization chamber. A plurality of primary axial air inlets are arranged in the same direction as the main premixed gas nozzle and surround the outside of the central axis of the flame stabilizer. A plurality of radial air inlets are arranged in a circumferential direction along the radial direction outside the flame stabilizer. A plurality of tangential air inlets are arranged around the outside of the flame stabilizer and are arranged obliquely relative to each other in the radial direction; by such an arrangement, a primary axial air inlet, radial air inlets, and tangential air inlets are arranged in the flame stabilization chamber, realizing a three-dimensional and cross-shaped jet structure formed by air flow strands with different angles, directions, and diameters and the air-fuel premixed gas flow in the flame stabilizer, and countless vortices with different scales, momenta, and directions will be formed, thereby generating countless possible flame residence points, greatly improving the flame stability, flame adjustment ratio, and combustion intensity of the burner.

[0014] Furthermore, the air-fuel premixer is also provided with a number of premixed gas radial flame-stabilizing nozzles. The main premixed gas nozzle is arranged axially at the downstream end of the air-fuel premixer. The number of premixed gas radial flame-stabilizing nozzles are arranged circumferentially in the radial direction outside the main premixed gas nozzle and placed in the flame-stabilizing chamber. With this arrangement, the air-fuel premixed auxiliary airflows generated by the premixed gas radial flame-stabilizing nozzles cooperate with the primary air jets generated by the primary air axial inlet at the upstream part of the flame stabilizer to form multiple stable ignition sources, thereby improving the flame stability of the burner.

[0015] Furthermore, a gas nozzle is provided at the downstream end of the gas conduit. An axial premixed gas inlet cooperating with the gas nozzle and a radial premixed air inlet circumferentially arranged outside the axial premixed gas inlet and communicating with the air delivery channel are provided at the upstream end of the air-fuel premixer. With this arrangement, multiple radial premixed air inlets in the air-fuel premixer premix with the gas input from the axial premixed gas inlet from multiple different directions and angles, and the mixing effect of air and gas is good.

[0016] Furthermore, a number of tangential air inlets are arranged at the same inclination angle in the radial direction. With this arrangement, while the airflows input by the tangential air inlets cut and slow down the air-fuel premixed jet input by the main premixed gas nozzle, they also push the air-fuel premixed airflow to rotate. The swirling flame forms a conical expanding flame under the action of centrifugal force at the outlet of the flame stabilizer, creating better conditions for mixing and burning with the airflows input by the secondary axial air inlets.

[0017] Alternatively, furthermore, a number of tangential air inlets are arranged at different inclination angles in the radial direction. With this arrangement, it is convenient for the generated air jets to form multiple flame-stabilizing ignition points at different plane heights with the gas jets generated by the gas nozzles respectively, enabling the flame-stabilizing burner to have a large gas regulation ratio and ensuring full combustion of the gas even when the gas flow rate at the gas nozzle is small, with good usage effects.

[0018] Furthermore, it also includes a flame ionization probe and an igniter arranged in the flame stabilizer. A flame rectifying tube is sleeved outside the downstream end of the flame stabilizer, and the flame tube is sleeved outside the flame rectifying tube and the downstream end of the burner body.

[0019] Another object of the present invention is to provide a flameless combustion device applying the low-emission high-speed burner, including a flameless burner and the low-emission high-speed burner. The flameless burner includes a flameless gas combustion tube, a flameless gas inlet provided at the input end of the flameless gas combustion tube, and a flameless gas combustion nozzle provided at the output end of the flameless gas combustion tube. By such an arrangement, since a certain critical furnace temperature condition (generally 750°C) is required for operating the flameless combustion mode, it cannot work below the critical furnace temperature condition and other combustion methods must be relied on. The low-emission high-speed burner of the present invention has excellent low-nitrogen performance at low temperatures. Therefore, by combining it with the flameless burner, the goal of ultra-low nitrogen throughout the process from low-temperature startup to high-temperature operation can be achieved.

[0020] Furthermore, at least two flameless burners are provided and arranged circumferentially outside the low-emission high-speed burner. One side of the flameless gas combustion tube close to the flameless gas combustion nozzle is arranged obliquely along the side of the flame nozzle of the low-emission high-speed burner. By such an arrangement, when the furnace temperature rises above the critical furnace temperature condition, the gas supply to the low-emission high-speed burner is closed, and at this time, the flame tube is only used for air delivery. When the gas supply to the flameless burner is turned on and the gas injection speed is not less than 80 m / s, the flameless burner and the low-emission high-speed burner are arranged at a relative angle, so that the gas jet and the air jet generated by the two attract and merge at a predetermined position. At the same time, the strong entrainment ability of the high-speed gas jet on the inert flue gas produces the ERG effect, which also further effectively inhibits the generation of NOx.

[0021] Another object of the present invention is to provide a method for igniting a flameless combustion device applying the flameless combustion device, which relates to the flameless combustion device provided in the furnace. The ignition method includes the following steps:

[0022] a. Gas and air are respectively introduced into the low-emission high-speed burner, and gas is introduced into the flameless burner. The igniter of the low-emission high-speed burner ignites the mixed gas composed of gas and air in the flame stabilizer to generate a flame at the flame nozzle.

[0023] b. When the furnace temperature reaches [720, 780]°C, the gas input to the low-emission high-speed burner is closed, thereby starting the flameless combustion mode of the flameless combustion device.

[0024] By such an arrangement, since a certain critical furnace temperature condition (generally 750°C) is required for operating the flameless combustion mode, it cannot work below the critical furnace temperature condition and other combustion methods must be relied on. The low-emission high-speed burner of the present invention has excellent low-nitrogen performance at low temperatures. Therefore, by combining it with the flameless burner, the goal of ultra-low nitrogen throughout the process from low-temperature startup to high-temperature operation can be achieved. Description of the Drawings

[0025] Figure 1Schematic diagram of a low-emission high-speed burner

[0026] Figure 2 Side view of a low-emission high-speed burner

[0027] Figure 3 Cross-sectional view of a low-emission high-speed burner

[0028] Figure 4 Cross-sectional view of a low-emission high-speed burner with the rocket launcher removed

[0029] Figure 5 Cross-sectional view of a low-emission high-speed burner in the working state

[0030] Figure 6 Schematic diagram of a premixed flame being generated at the premixed flame nozzle of a flame stabilizer

[0031] Figure 7 Working state diagram of air flowing into the tangential air inlet and radial air inlet of a flame stabilizer

[0032] Figure 8 Schematic diagram of a circular flame nozzle

[0033] Figure 9 Schematic diagram of a rectangular flame nozzle

[0034] Figure 10 Schematic diagram of a butterfly-shaped flame nozzle

[0035] Figure 11 Schematic diagram of an oval flame nozzle

[0036] Figure 12 Cross-sectional view of a gas conduit and an air-fuel premixer

[0037] Figure 13 Cross-sectional view of the gas conduit and air-fuel premixer of Example 1

[0038] Figure 14 Schematic diagram of a flameless combustion device

[0039] Figure 15 Line graph showing the variation of NOx emissions of a low-emission high-speed burner with furnace temperature

[0040] Figure 16 Line graph showing the variation of NOx emissions during combustion in the dual-mode of flameless combustion and with-flame combustion of Example 2 and Example 3 with furnace temperature Detailed implementation method

[0041] The technical solution of the present invention will be described below in conjunction with the accompanying drawings:

[0042] Example 1:

[0043] SeeFigures 1 to 15 , the low-emission high-speed burner 10 of the present invention includes: a burner body 1, a gas input device 2, an air-fuel premixer 3, a flame stabilizer 4, and a flame tube 5. The central axes of the burner body 1, the air-fuel premixer 3, the flame stabilizer 4, and the flame tube 5 are arranged in the same direction.

[0044] The burner body 1 is provided with a gas conduit 11 inside, an air delivery channel 12, and an air inlet 121 communicating with the air delivery channel 12. The gas conduit 11 is arranged inside the air delivery channel 12, and the air delivery channel 12 is arranged around the outside of the gas conduit 11 along the axial direction.

[0045] The gas input device 2 is connected to the upstream end of the gas conduit 11 and is provided with a gas inlet 21 communicating with the gas conduit 11.

[0046] The air-fuel premixer 3 is a hollow cylindrical structure, provided with an air-fuel premixing chamber 31 respectively communicating with the gas conduit 11 and the air delivery channel 12, and a main premixed gas spray port 32 communicating with the air-fuel premixing chamber 31.

[0047] The flame stabilizer 4 is sleeved on the downstream end of the air-fuel premixer 3, and is provided with a flame stabilizing chamber 41 communicating with the main premixed gas spray port 32, a plurality of primary axial air inlets 42 communicating with the flame stabilizing chamber 41, a plurality of secondary axial air inlets 43 located outside the flame stabilizer 4 and communicating with the air delivery channel 12, and a premixed flame spray port 44 formed at the downstream end of the flame stabilizer 4 and having a plurality of lobe-like structures 441 in the circumferential direction. The primary axial air inlets 42 are arranged at the upstream end of the flame stabilizer 4 and are arranged in the same direction as the main premixed gas spray port 32. A plurality of secondary air delivery channels 431 are arranged circumferentially along the length direction outside the flame stabilizer 4. The secondary axial air inlets 43 are arranged at the downstream ports of the secondary air delivery channels 431, and the secondary axial air inlets 43 are located between the adjacent lobe-like structures 441 of the premixed flame spray port 44.

[0048] The flame tube 5 is located at the downstream end of the burner body 1 and communicates with the flame stabilizing chamber 41, and is provided with a flame spray port 51 with a gradually narrowing diameter communicating with the flame stabilizing chamber 41. The premixed flame spray port 44 is located inside the flame tube 5.

[0049] The premixed flame spray port 44 having a plurality of lobe-like structures 441 in the circumferential direction, for example, the premixed flame spray port 44 is a hole-like structure with a plurality of semi-circular or semi-elliptical holes arranged circumferentially.

[0050] Compared with the prior art, in the low-emission high-speed burner 10 of the present invention, by respectively arranging a primary axial air inlet 42 inside the flame stabilizer 4 and a secondary axial air inlet 43 outside the flame stabilizer 4, the air flow conveyed by the air delivery channel 12 enters the flame stabilizer 4 in multiple paths to perform staged combustion with the air-fuel premixed gas flow discharged from the air-fuel premixer 3, and staged combustion is formed to form a primary combustion zone 442 and a secondary combustion zone 443 at the premixed flame nozzle 44 of the flame stabilizer 4. Its full combustion reaction better inhibits the generation of NOx; the secondary axial air inlet 43 is arranged between adjacent lobe-shaped structures 441, strengthening the effective mixing of the air flow generated by it and the premixed flame generated by the premixed flame nozzle 44. At the same time, multiple relatively complex premixed flame vortex airflows will be formed between the lobe structure outlet and the lip of the premixed flame nozzle 44, becoming a reliable flame stabilization structure for the secondary combustion of the premixed flame. And the premixed flame vortex airflow forms a conical expanding flame under the action of centrifugal force during rotation, better mixing and burning further with the air ejected from the secondary axial air inlet 43 when discharging from the premixed flame nozzle 44. Moreover, the premixed flame burns rapidly in the flame tube 5 with a constricted flame nozzle 51. The high temperature causes the gas to expand, generating a certain back pressure inside the flame tube 5. This back pressure drives the flame to be ejected at high speed from the flame nozzle 51, thus strengthening the in-furnace flue gas recirculation combustion, inhibiting the generation of NOx and CO, enabling the gas fuel to burn fully better, and reducing the emissions of nitrogen oxides and combustion particulates, with good use effects.

[0051] See Figures 1 to 7 , in an embodiment, the flame nozzle 51 is a butterfly-shaped nozzle with a flat middle part and the diameters of adjacent two sides increasing outward; by setting it like this, by adjusting the gas flow distribution in the length direction of the flame nozzle 51, a more uniform flat flame can be obtained, making the flame have better heating performance. At the same time, due to having a larger contact surface area with the furnace gas, the entrainment and suction ability of the flame can be improved, and the heat dissipation and cooling of the furnace gas can be made faster, with a stronger ability to inhibit the generation of NOx.

[0052] Since the flame stabilizer 4 provides an excellent mixing effect of gas and air, greatly improving the combustion intensity and the combustion chamber back pressure inside the flame tube 5, enabling the flame tube 5 to have the basic conditions for realizing ultra-high-speed flame jet. Due to the excellent flame stabilization performance of the flame stabilizer 4, the combustion boundary conditions of the burner are greatly extended, making the burner have an ultra-wide adjustment range.

[0053] In other embodiments, the flame nozzle 51 can be oval-shaped, round-hole-shaped, rectangular-shaped, strip-shaped or rectangular-shaped, etc.

[0054] See Figures 3 to 7, in one embodiment, the flame stabilizer 4 is further provided with a plurality of radial air inlets 45 and a plurality of tangential air inlets 46 communicating with the flame stabilization chamber 41. A plurality of primary axial air inlets 42 are arranged in the same direction as the premixed gas main nozzle 32 and surround the outer side of the central axis of the flame stabilizer 4. The primary axial air inlets 42 can be arranged in one or more rings. A plurality of radial air inlets 45 are arranged in a circumferential direction along the radial direction on the outer side of the flame stabilizer 4. A plurality of tangential air inlets 46 are arranged around the outer side of the flame stabilizer 4 and are arranged obliquely relative to each other in the radial direction. The plurality of tangential air inlets 46 are arranged at intervals from the plurality of radial air inlets 45. The plurality of tangential air inlets 46 are arranged downstream of the plurality of radial air inlets 45. The circumferentially adjacent tangential air inlets 46 are arranged in a staggered manner, and the circumferentially adjacent radial air inlets 45 are arranged in a staggered manner. By such an arrangement, the primary axial air inlets 42, the radial air inlets 45 and the tangential air inlets 46 are arranged in the flame stabilization chamber 41, so as to form a three-dimensional and cross-shaped jet structure of air flow streams with different angles, directions and diameters and the air-fuel premixed gas flow in the flame stabilizer 4, and countless vortices with different scales, momenta and directions will be formed, thereby generating countless possible flame stagnation points, and greatly improving the flame stability, flame adjustment ratio and combustion intensity of the burner.

[0055] See Figures 3 to 7 , in one embodiment, the air-fuel premixer 3 is further provided with a plurality of premixed gas radial flame stabilizing nozzles 33. The premixed gas main nozzle 32 is arranged along the axial direction at the downstream end of the air-fuel premixer 3. A plurality of premixed gas radial flame stabilizing nozzles 33 are arranged in a circumferential direction along the radial direction on the outer side of the premixed gas main nozzle 32 and are arranged in the flame stabilization chamber 41. By such an arrangement, the air-fuel premixed auxiliary air flow generated by the premixed gas radial flame stabilizing nozzles 33 cooperates with the primary air jet generated by the primary air axial input port at the upstream part of the flame stabilizer 4 to form a plurality of stable ignition sources, thereby improving the flame stability of the burner.

[0056] See Figures 3 to 7 , Figure 12 and Figure 13 , in one embodiment, a gas nozzle 13 is provided at the downstream end of the gas conduit 11. The gas nozzle 13 can be a single-hole or multi-hole gas nozzle 13. An axial premixed gas inlet 34 cooperating with the gas nozzle 13 and a radial premixed air inlet 35 arranged circumferentially outside the axial premixed gas inlet 34 and communicating with the air delivery channel 12 are provided at the upstream end of the air-fuel premixer 3. By such an arrangement, the plurality of radial premixed air inlets 35 in the air-fuel premixer 3 premix the gas input from the axial premixed gas inlet 34 from multiple different directions and angles, and the mixing effect of air and gas is good.

[0057] See Figures 3 to 7, in this embodiment, a plurality of tangential air inlets 46 are arranged at the same inclination angle in the radial direction; by setting like this, the air jet input by the radial air inlet 45 "crushes" the air-fuel premixed jet input by the premixed gas main nozzle 32. While promoting mixing, the air flow input by the tangential air inlet 46 cuts and slows down the air-fuel premixed jet input by the premixed gas main nozzle 32 and at the same time pushes the air-fuel premixed gas flow to rotate. The swirling flame forms a conical expanding flame under the action of centrifugal force at the outlet of the flame stabilizer 4, creating better conditions for mixing and burning with the air flow input by the secondary axial air inlet 43.

[0058] In an alternative embodiment (not shown in the figure), a plurality of tangential air inlets 46 are arranged at different inclination angles in the radial direction; by setting like this, it is convenient for the generated air jets to form a plurality of flame stabilization and ignition points at different plane heights with the gas jets generated by the gas nozzles respectively, enabling the flame stabilization burner to have a large gas regulation ratio and ensuring full combustion of the gas even when the gas flow rate of the gas nozzle is small, with good use effects.

[0059] See Figure 1 , in one embodiment, it further includes a flame ionization probe 47 and an igniter 48 disposed in the flame stabilizer 4; a flame rectifying tube 49 is sleeved outside the downstream end of the flame stabilizer 4, and the flame tube 5 is sleeved outside the flame rectifying tube 49 and the downstream end of the burner body 1.

[0060] See Figures 3 to 7, when the low-emission high-speed burner 10 of the present invention is working, air is introduced into the air passage from the air input port 121 respectively, and gas is introduced into the gas input port 21; the gas enters the air-fuel premixing chamber 31 of the air-fuel premixer 3 in the axial direction through the gas conduit 11, the gas nozzle 13 and the axial premixed gas inlet 34, and the air enters the air-fuel premixing chamber 31 of the air-fuel premixer 3 at different radial angles from the radial premixed air inlet 35 respectively, and is fully mixed with the gas to form an air-fuel premixed gas flow; the air-fuel premixed gas flow enters the flame stabilization chamber 41 from the main premixed gas nozzle 32 in the axial direction and the plurality of premixed gas radial flame stabilization nozzles 33 in the radial direction respectively. In addition, part of the air in the air passage enters the flame stabilization chamber 41 from the primary axial air inlet 42, the radial air inlet 45 and the tangential air inlet 46 at multiple different angles to further mix with the air-fuel premixed gas flow, and burns to generate a flame under the action of the igniter 48; the air jet input from the radial air inlet 45 shatters and slows down the air-fuel premixed jet input from the main premixed gas nozzle 32, promotes mixing, and at the same time, cooperates with the air flow input from the tangential air inlet 46 to cut and slow down the air-fuel premixed jet input from the main premixed gas nozzle 32 while pushing the air-fuel premixed gas flow to rotate. The swirling flame forms a conical expanding flame under the action of the centrifugal force at the outlet of the flame stabilizer 4 and the action of the lobe structure outlet. The formed conical expanding flame further mixes and burns with the air ejected from the secondary axial air inlet 43 after being discharged from the premixed flame nozzle 44 in the flame tube 5, and finally is ejected at high speed from the flame nozzle 51 through the back pressure inside the flame tube 5.

[0061] Embodiment 2:

[0062] See Figures 1 to 16 , the main purpose of this embodiment is to provide a flameless combustion device applying the low-emission high-speed burner 10 of Embodiment 1, which includes a flameless burner 6 and the low-emission high-speed burner 10. The flameless burner 6 includes a flameless gas combustion tube 61, a flameless gas inlet (not shown in the figure) provided at the input end of the flameless gas combustion tube 61, and a flameless gas combustion nozzle 63 provided at the output end of the flameless gas combustion tube 61. By setting like this, since a certain critical furnace temperature condition (generally 750 °C) is required to operate the flameless combustion mode, it cannot work below the critical furnace temperature condition and must rely on other combustion methods. The low-emission high-speed burner 10 of the present invention has excellent low-nitrogen performance at low temperatures. Therefore, combining it with the flameless burner 6 can achieve the goal of ultra-low nitrogen throughout the process from low-temperature start-up to high-temperature operation.

[0063] See Figures 1 to 16, in a further embodiment, it further includes a burner block 7, the flameless burner 6 and the low-emission high-speed burner 10 are installed and fixed on the burner block 7. There are at least two flameless burners 6, and they are circumferentially arranged outside the low-emission high-speed burner 10. One side of the flameless gas combustion tube 61 close to the flameless gas combustion nozzle 63 is inclined along one side of the flame nozzle 51 of the low-emission high-speed burner 10. By such an arrangement, when the furnace temperature rises above the critical furnace temperature condition, the gas supply to the low-emission high-speed burner 10 is closed, and at this time the flame tube 5 is only used for air delivery. When the gas supply to the flameless burner 6 is turned on, the gas injection speed is not lower than 80 m / s. The flameless burner 6 and the low-emission high-speed burner 10 are arranged at a relative angle, so that the gas jet and the air jet generated by the two attract and merge at a predetermined position. At the same time, the strong entrainment ability of the high-speed gas jet to the inert flue gas produces the ERG effect, which promotes the recirculation of the high-temperature flue gas inside or outside, and also effectively suppresses the generation of NOx.

[0064] Embodiment Three:

[0065] See Figures 1 to 16 , the main purpose of this embodiment is to provide a method for igniting a flameless combustion device applying the flameless combustion device in Embodiment Two, which relates to the flameless combustion device provided in the furnace. The ignition method includes the following steps:

[0066] a. Gas and air are respectively introduced into the low-emission high-speed burner 10, and gas is introduced into the flameless burner 6. The igniter 48 of the low-emission high-speed burner 10 ignites the mixed gas composed of gas and air in the flame stabilizer 4, so that a flame is generated at the flame nozzle 51.

[0067] b. When the furnace temperature reaches [720, 780] °C, the gas input to the low-emission high-speed burner 10 is closed, thereby starting the flameless combustion mode of the flameless combustion device.

[0068] By such an arrangement, since operating the flameless combustion mode requires a certain critical furnace temperature condition (generally 750 °C), it cannot work below the critical furnace temperature condition and must rely on other combustion methods. The low-emission high-speed burner 10 of the present invention has excellent low-nitrogen performance at low temperatures. Therefore, combining it with the flameless burner 6 can achieve the goal of ultra-low nitrogen throughout the process from low-temperature startup to high-temperature operation.

[0069] Based on the disclosure and teachings of the above specification, those skilled in the art to which the present invention pertains can also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.

Claims

1. A low-emission high-speed burner, characterized in that, Comprising: A burner body, provided with a gas conduit located inside, an air delivery channel, and an air inlet communicating with the air delivery channel. The air delivery channel is arranged in a surrounding manner outside the gas conduit along the axial direction; A gas inlet device, connected to the upstream end of the gas conduit, and provided with a gas inlet communicating with the gas conduit; An air-fuel premixer, provided with an air-fuel premixing chamber respectively communicating with the gas conduit and the air delivery channel, and a main premixed gas injection port communicating with the air-fuel premixing chamber; A flame stabilizer, provided with a flame stabilization chamber communicating with the main premixed gas injection port, a plurality of primary axial air inlet ports communicating with the flame stabilization chamber, a plurality of secondary axial air inlet ports located outside the flame stabilizer and communicating with the air delivery channel, and a premixed flame injection port having a plurality of lobe-shaped structures circumferentially at the downstream end of the flame stabilizer. The secondary axial air inlet ports are located between adjacent lobe-shaped structures; A flame tube, located at the downstream end of the burner body, and provided with a flame injection port with a gradually narrowing diameter communicating with the flame stabilization chamber; The burner body, the air-fuel premixer, the flame stabilizer, and the flame tube have the same central axis direction; 2. The low-emission high-speed burner according to claim 1, characterized in that, The flame injection port is a butterfly-shaped injection port with a flat middle part and the diameters of adjacent two sides increasing outward; 3. The low-emission high-speed burner according to claim 1, characterized in that, The flame stabilizer is further provided with a plurality of radial air inlet ports and a plurality of tangential air inlet ports communicating with the flame stabilization chamber. The plurality of primary axial air inlet ports are arranged in the same direction as the main premixed gas injection port and surround the outside of the central axis of the flame stabilizer. The plurality of radial air inlet ports are arranged in a surrounding manner along the radial direction outside the flame stabilizer. The plurality of tangential air inlet ports are arranged in a surrounding manner outside the flame stabilizer and are arranged obliquely relative to each other along the radial direction; 4. The low-emission high-speed burner according to claim 1, characterized in that, The air-fuel premixer is further provided with a plurality of premixed gas radial flame stabilization injection ports. The main premixed gas injection port is arranged along the axial direction at the downstream end of the air-fuel premixer. The plurality of premixed gas radial flame stabilization injection ports are arranged in a circumferential manner along the radial direction outside the main premixed gas injection port and are placed in the flame stabilization chamber; 5. The low-emission high-speed burner according to claim 1, characterized in that, A gas nozzle is provided at the downstream end of the gas conduit. An axial premixed gas inlet cooperating with the gas nozzle and a radial premixed air inlet communicating with the air delivery channel are provided circumferentially outside the axial premixed gas inlet at the upstream end of the air-fuel premixer; 6. The low-emission high-speed burner according to claim 3, characterized in that, The plurality of tangential air inlet ports are arranged at the same inclination angle along the radial direction; Or, the plurality of tangential air inlet ports are arranged at different inclination angles along the radial direction; 7. The low-emission high-speed burner according to any one of claims 1 to 6, characterized in that, It further includes a flame ionization probe and an igniter arranged in the flame stabilizer; A flame rectifying tube is sleeved outside the downstream end of the flame stabilizer, and the flame tube is sleeved outside the flame rectifying tube and the downstream end of the burner body; 8. Flameless combustion device, characterized in that, Comprising a flameless burner and the low-emission high-speed burner according to any one of claims 1 to 7. The flameless burner includes a flameless gas combustion tube, a flameless gas inlet provided at the input end of the flameless gas combustion tube, and a flameless gas combustion nozzle provided at the output end of the flameless gas combustion tube; 9. The flameless combustion device according to claim 8, wherein At least two flameless burners are provided and are arranged circumferentially outside the low-emission high-speed burner. One side of the flameless gas combustion tube close to the flameless gas combustion nozzle is arranged obliquely along the side of the flame injection port of the low-emission high-speed burner; 10. Method for igniting flameless combustion device, relating to the flameless combustion device described in claim 8 or 9 provided in a furnace, characterized in that, The ignition method includes the following steps: a. Feed gas and air into the low-emission high-speed burner respectively, and feed gas into the flameless burner. The igniter of the low-emission high-speed burner ignites the gas-air mixture in the flame stabilizer to produce a flame at the flame nozzle. b. When the furnace temperature reaches [720,780] °C, shut off the gas input to the low-emission high-speed burner to start the flameless combustion mode of the flameless combustion device.

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