Dual-fuel low-nitrogen combustor

Abstract

The invention discloses a dual-fuel low-nitrogen combustor which comprises a biomass gas combustion device and a natural gas combustion device, and the biomass gas combustion device comprises a biomass gas combustion device air channel structure and a biomass gas combustion device gas channel structure. The natural gas combustion device comprises a natural gas combustion device air channel structure and a natural gas combustion device fuel gas channel structure. The biomass gas combustion device air channel structure, the biomass gas combustion device gas channel structure, the natural gas combustion device air channel structure and the natural gas combustion device gas channel structure are sequentially connected in a sleeving mode from outside to inside and are coaxially arranged. According to the energy supply system, flexible switching and independent combustion of the combustor between biomass gas combustion and natural gas combustion can be achieved, meanwhile, co-combustion of biomass gas and natural gas can be achieved, the raw material applicability of the combustor is improved, and the operation stability and safety of the energy supply system are effectively guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of burners, and more particularly to a dual-fuel low-nitrogen burner. Background Art

[0002] The gas produced by biomass gasification is a low-calorific-value gas, and the burner is an important link for energy conversion in the biomass gasification energy supply system. At present, there are still some problems in the stability of system use and non-compliance of emissions in most biomass gasification energy supply projects.

[0003] Specifically, on the one hand, the burners used in biomass gasification energy supply are generally single biomass gas burners. Once the biomass gasification system fails and it is impossible to ensure the stable supply of biomass gas, the single biomass gas burner will not be able to work. Because the calorific value of biomass gas is relatively low, the structural dimensions of the gas and air channels of the biomass gas burner are very different from those of the burner using natural gas, and it is impossible to switch to natural gas as fuel, and a set of standby natural gas energy supply devices are required; on the other hand, conventional biomass gas burners generally adopt a diffusion combustion method, that is, the gas and the combustion-supporting air respectively form a mixed gas flow outside the burner through their respective nozzles and then burn. There is often an uneven distribution of the biomass gas concentration in the mixed gas flow of the biomass gas and the air, resulting in an uneven distribution of the flame temperature during combustion, and the local temperature of the flame is too high, resulting in an increase in the concentration of nitrogen oxides in the flue gas generated after the system combustion.

[0004] Therefore, providing a dual-fuel low-nitrogen burner is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a dual-fuel low-nitrogen burner to at least solve one of the technical problems mentioned in the above background art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A dual-fuel low-nitrogen burner includes a biomass gas combustion device and a natural gas combustion device. The biomass gas combustion device includes a biomass gas combustion device air channel structure and a biomass gas combustion device gas channel structure. The natural gas combustion device includes a natural gas combustion device air channel structure and a natural gas combustion device gas channel structure. The biomass gas combustion device air channel structure, the biomass gas combustion device gas channel structure, the natural gas combustion device air channel structure, and the natural gas combustion device gas channel structure are sleeved and connected in sequence from outside to inside and arranged coaxially.

[0008] By adopting the above technical solutions, the beneficial effects of the present invention are:

[0009] Combining a biomass gas combustion device and a natural gas combustion device in a sleeve form enables the burner to flexibly switch between burning biomass gas and natural gas, burn them separately, and also achieve co-combustion of biomass gas and natural gas, improving the raw material applicability of the burner and effectively ensuring the operation stability and safety of the energy supply system.

[0010] Further, the air passage structure of the biomass gas combustion device includes a first air static pressure chamber, an air duct, an air flow equalizing orifice plate, and a first air intake duct. The end face of the first air static pressure chamber close to the downstream of the air flow is connected and communicated with the inlet end of the air duct, and the first air static pressure chamber and the air duct are coaxially arranged. The air flow equalizing orifice plate has a plurality of evenly distributed rectifying holes, and the air flow equalizing orifice plate is fixed inside the air duct and located on the side close to the outlet of the air duct. One end of the first air intake duct is connected and communicated with the side face of the first air static pressure chamber, and the first air intake duct is radially distributed along the first air static pressure chamber. The extended end of the first air intake duct has a first air inlet.

[0011] Further, the gas passage structure of the biomass gas combustion device includes a biomass gas static pressure chamber, a plurality of biomass gas branch ducts, a plurality of biomass gas nozzles, and a biomass gas intake duct. The plurality of biomass gas branch ducts are arranged annularly around the axis of the biomass gas static pressure chamber and are connected and communicated with the end face of the biomass gas static pressure chamber close to the downstream of the air flow. The end face of the first air static pressure chamber close to the upstream of the air flow has a first through hole corresponding to the position of the biomass gas branch ducts, and the air flow equalizing orifice plate has a second through hole corresponding to the position of the biomass gas branch ducts. The plurality of biomass gas branch ducts are respectively inserted into the plurality of first through holes and the plurality of second through holes. The plurality of biomass gas nozzles are respectively installed at the outlet ends of the plurality of biomass gas branch ducts. One end of the biomass gas intake duct is connected and communicated with the side face of the biomass gas static pressure chamber, and the biomass gas intake duct is radially distributed along the biomass gas static pressure chamber. The extended end of the biomass gas intake duct has a biomass gas inlet.

[0012] The beneficial effects of adopting the above further technical solution are that by combining a plurality of biomass gas branch ducts, biomass gas nozzles, and an air flow equalizing orifice plate, uniform mixing of biomass gas and combustion-supporting air is achieved, avoiding local overheating of the flame due to uneven gas concentration, and effectively reducing Nox emissions.

[0013] Further, each of the biomass gas nozzles includes a plurality of gas nozzle sleeves and a sealing end plate. The plurality of gas nozzle sleeves are arranged at intervals and coaxially from the inside to the outside in sequence; a plurality of swirl vanes are provided between every two adjacent gas nozzle sleeves to form a swirl channel for the biomass gas; the sealing end plate is fixed to the outlet end of the innermost gas nozzle sleeve.

[0014] Further, the air channel structure of the natural gas combustion device includes a second air static pressure chamber, a premixed gas pipeline, a second air inlet pipeline, a backfire prevention orifice plate, and a premixed gas nozzle. The end face of the second air static pressure chamber close to the downstream of the air flow is connected and communicated with the inlet end of the premixed gas pipeline, and the second air static pressure chamber and the premixed gas pipeline are coaxially arranged; both end faces of the biomass gas static pressure chamber have a third through hole in the center, the end face of the first air static pressure chamber close to the upstream of the air flow has a fourth through hole, the air flow equalizing orifice plate has a fifth through hole in the center, and the premixed gas pipeline is sequentially inserted into the third through hole, the fourth through hole, and the fifth through hole; one end of the second air inlet pipeline is connected and communicated with the side face of the second air static pressure chamber, and the second air inlet pipeline is distributed radially along the second air static pressure chamber; the extended end of the second air inlet pipeline has a second air inlet; the backfire prevention orifice plate and the premixed gas nozzle are sequentially installed at the outlet end of the premixed gas pipeline along the air flow direction.

[0015] Further, the backfire prevention orifice plate has a plurality of uniformly distributed round holes or grid holes with a hole diameter smaller than the flame extinction distance.

[0016] The beneficial effect of adopting the above further technical solution is that the backfired flame cannot spread through the small holes, effectively blocking the occurrence of backfire.

[0017] Further, the premixed gas nozzle includes a plurality of premixed gas nozzle sleeves and a premixed gas central plate. The plurality of premixed gas nozzle sleeves are arranged at intervals and coaxially from the inside to the outside in sequence; a plurality of swirl channel fins are provided between every two adjacent premixed gas nozzle sleeves to form a swirl channel for the premixed gas; the premixed gas central plate has a plurality of premixed gas central holes in the center; the premixed gas central plate is fixed to the outlet end of the innermost premixed gas nozzle sleeve.

[0018] The beneficial effect of adopting the above further technical solution is that by using a spiral swirl channel, the propagation distance of the backfired flame is increased, so that the heat dissipation of the flame in the channel is greater than the heat released by combustion. After the flame temperature decreases, cold wall flameout is achieved, further preventing the occurrence of backfire and ensuring the safe operation of combustion.

[0019] Furthermore, the gas passage structure of the natural gas combustion device includes a natural gas pipeline, a reducing pipe, a natural gas premixing nozzle, a cylinder, and natural gas premixing swirl vanes. The natural gas pipeline has a natural gas inlet; the natural gas pipeline, the reducing pipe, the natural gas premixing nozzle, and the cylinder are connected together in sequence along the gas flow direction and are coaxially arranged; the end face of the second air static pressure chamber close to the upstream of the gas flow has a sixth through hole, and the natural gas pipeline is inserted into the sixth through hole; the natural gas premixing nozzle has a plurality of uniformly distributed natural gas nozzles along its circumference; both ends of the natural gas premixing swirl vanes are fixedly connected to the inner wall of the cylinder and the premixed gas pipeline respectively.

[0020] The beneficial effect of adopting the above further technical solution is that by combining the premixed gas nozzle and the natural gas premixing swirl vanes, natural gas is premixed with air, strengthening the mixing effect of natural gas and air, avoiding excessive local gas concentration and combustion temperature, and reducing Nox emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0022] Figure 1 The drawing is a partially cut-away three-dimensional structural schematic diagram of a dual-fuel low-nitrogen burner provided by the present invention;

[0023] Figure 2 The drawing is a structural schematic diagram of the air passage structure of the biomass gas combustion device provided by the present invention;

[0024] Figure 3 The drawing is a structural schematic diagram of the gas passage structure of the biomass gas combustion device provided by the present invention;

[0025] Figure 4 The drawing is a structural schematic diagram of the air passage structure of the natural gas combustion device provided by the present invention;

[0026] Figure 5 The drawing is a structural schematic diagram of the gas passage structure of the natural gas combustion device provided by the present invention;

[0027] Figure 6 The drawing is a structural schematic diagram of the biomass gas nozzle provided by the present invention;

[0028] Figure 7 The drawing is a structural schematic diagram of the premixed gas nozzle provided by the present invention. Specific Embodiments

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] As Figure 1-7 shown, the embodiment of the present invention discloses a dual-fuel low-nitrogen burner, which includes a biomass gas combustion device and a natural gas combustion device. The biomass gas combustion device includes a biomass gas combustion device air passage structure 1 and a biomass gas combustion device gas passage structure 2. The natural gas combustion device includes a natural gas combustion device air passage structure 3 and a natural gas combustion device gas passage structure 4. The biomass gas combustion device air passage structure 1, the biomass gas combustion device gas passage structure 2, the natural gas combustion device air passage structure 3, and the natural gas combustion device gas passage structure 4 are sleeved and connected in sequence from outside to inside and arranged coaxially, that is, arranged in a coaxial sleeve form. The present invention combines the biomass gas combustion device and the natural gas combustion device in a sleeve form, which can realize the flexible switching between burning biomass gas and natural gas, burning alone, and can also realize the co-combustion of biomass gas and natural gas, improving the raw material applicability of the burner and effectively ensuring the operation stability and safety of the energy supply system.

[0031] Specifically, the biomass gas combustion device air passage structure 1 includes a first air static pressure chamber 11, an air pipe 12, an air flow equalizing orifice plate 13, and a first air intake pipe 14. The end face of the first air static pressure chamber 11 close to the downstream of the air flow is connected and communicated with the inlet end of the air pipe 12, and the first air static pressure chamber 11 and the air pipe 12 are arranged coaxially, that is, the air static pressure chamber 11 is upstream of the air flow and the air passage 12 is downstream of the air flow; the air flow equalizing orifice plate 13 has a plurality of uniformly distributed rectifying holes 131. In this embodiment, the rectifying holes 131 are circular small holes. The air flow equalizing orifice plate 13 is fixed inside the air pipe 12 and is located on the side close to the outlet of the air pipe 12; one end of the first air intake pipe 14 is connected and communicated with the side surface of the first air static pressure chamber 11, and the first air intake pipe 14 is distributed radially along the first air static pressure chamber 11; the extended end of the first air intake pipe 14 has a first air inlet 141.

[0032] Specifically, the gas channel structure 2 of the biomass gas combustion device includes a biomass gas plenum 21, a plurality of biomass gas branch pipes 22, a plurality of biomass gas nozzles 23 and a biomass gas inlet pipe 24. The plurality of biomass gas branch pipes 22 are arranged in a ring around the axis of the biomass gas plenum 21 and are connected to the end face of the biomass gas plenum 21 close to the downstream of the air flow, effectively ensuring that the biomass gas and the combustion-supporting air are fully and evenly mixed, avoiding the uneven flame temperature caused by the uneven local gas concentration, thereby achieving the purpose of reducing the nitrogen oxide content in the flue gas; the end face of the first air plenum 11 close to the upstream of the air flow The air flow balancing orifice plate 13 has a first through hole corresponding to the position of the biomass gas branch pipe 22, and the air flow balancing orifice plate 13 has a second through hole 132 corresponding to the position of the biomass gas branch pipe 22. Multiple biomass gas branch pipes 22 are respectively inserted into the multiple first through holes and the multiple second through holes 132. Multiple biomass gas nozzles 23 are respectively installed at the outlet ends of the multiple biomass gas branch pipes 22. One end of the biomass gas inlet pipe 24 is connected to and communicates with the side of the biomass gas plenum 21, and the biomass gas inlet pipes 24 are radially distributed along the biomass gas plenum 21. The extended end of the biomass gas inlet pipe 24 has a biomass gas inlet 241. The present invention combines multiple biomass gas branch pipes 22, biomass gas nozzles 23, and air flow balancing orifice plate 13 to achieve uniform mixing of biomass gas and combustion-supporting air, avoid excessively high local flame temperatures due to uneven gas concentration, and effectively reduce NOx emissions.

[0033] Specifically, each biomass gas nozzle 23 includes a plurality of gas nozzle sleeves 231 and a sealing end plate 232. The plurality of gas nozzle sleeves 231 are arranged in sequence from the inside to the outside and are coaxially arranged. A plurality of swirl blades 233 are provided between each two adjacent gas nozzle sleeves 231 to form a swirl channel for the biomass gas. The sealing end plate 232 is fixed to the outlet end of the innermost gas nozzle sleeve 231.

[0034] Specifically, the air passage structure 3 of the natural gas combustion device includes a second air static pressure chamber 31, a premixed gas pipeline 32, a second air inlet pipeline 33, an anti-backfire orifice plate 34, and a premixed gas nozzle 35. The end face of the second air static pressure chamber 31 close to the downstream of the air flow is connected and communicated with the inlet end of the premixed gas pipeline 32, and the second air static pressure chamber 31 and the premixed gas pipeline 32 are coaxially arranged, that is, the second air static pressure chamber 31 is upstream of the air flow and the premixed gas pipeline 32 is downstream of the air flow; there is a third through hole in the center of both end faces of the biomass gas static pressure chamber 21, there is a fourth through hole in the end face of the first air static pressure chamber 11 close to the upstream of the air flow, and there is a fifth through hole 133 in the center of the air flow equalizing orifice plate 13; the premixed gas pipeline 32 is sequentially inserted into the third through hole, the fourth through hole, and the fifth through hole 133; one end of the second air inlet pipeline 33 is connected and communicated with the side surface of the second air static pressure chamber 31, and the second air inlet pipeline 33 is radially distributed along the second air static pressure chamber 31; the extended end of the second air inlet pipeline 33 has a second air inlet 331; the anti-backfire orifice plate 34 and the premixed gas nozzle 35 are sequentially installed at the outlet end of the premixed gas pipeline 32 along the air flow direction.

[0035] To further optimize the technical solution of the present invention, the anti-backfire orifice plate 34 has a plurality of uniformly distributed round holes or grid holes with apertures smaller than the flame extinction distance, so that the backfired flame cannot propagate through the small holes, effectively blocking the occurrence of backfire.

[0036] Specifically, the premixed gas nozzle 35 includes a plurality of premixed gas nozzle sleeves 351 and a premixed gas central plate 352. The plurality of premixed gas nozzle sleeves 351 are sequentially arranged at intervals from the inside to the outside and are coaxially arranged; a plurality of swirl channel fins 353 are provided between every two adjacent premixed gas nozzle sleeves 351 to form a swirl channel for the premixed gas; the premixed gas central plate 352 has a plurality of premixed gas central holes 3521 in the center, and a small amount of premixed gas is ejected from the premixed gas central holes 3521 for generating a central flame; the premixed gas central plate 352 is fixed at the outlet end of the innermost premixed gas nozzle sleeve 351. The present invention adopts a spiral swirl channel to increase the propagation distance of the backfired flame, so that the heat dissipation of the flame in the channel is greater than the heat released by combustion, and the flame is extinguished by the cold wall after the flame temperature decreases, further preventing the occurrence of backfire and ensuring the safe operation of combustion.

[0037] Specifically, the gas passage structure 4 of the natural gas combustion device includes a natural gas pipeline 41, a reducing pipe 42, a natural gas premixing nozzle 43, a cylinder 44, and natural gas premixing swirl vanes 45. The natural gas pipeline 41 has a natural gas inlet 411. The natural gas pipeline 41, the reducing pipe 42, the natural gas premixing nozzle 43, and the cylinder 44 are connected together in sequence along the gas flow direction and are coaxially arranged. The end face of the second air static pressure chamber 31 close to the upstream of the gas flow has a sixth through hole, and the natural gas pipeline 41 is inserted into the sixth through hole. The natural gas premixing nozzle 43 has a plurality of uniformly distributed natural gas nozzles 431 along its circumferential direction. In this embodiment, they are circular. The two ends of the natural gas premixing swirl vanes 45 are respectively fixedly connected to the inner wall of the cylinder 44 and the premixed gas pipeline 32. Here, the cylinder 44 is used to seal the pipeline of the natural gas premixing nozzle, so that natural gas is ejected from the natural gas nozzle 431, and on the other hand, it is used to support the natural gas premixing swirl vanes 45. The present invention combines the premixed gas nozzle 35 and the natural gas premixing swirl vanes 45 to premix natural gas and air, strengthens the mixing effect of natural gas and air, avoids too high local gas concentration and combustion temperature, and reduces NOx emissions.

[0038] The working principle of the present invention:

[0039] When the biomass gas combustion device operates, air enters the first air static pressure chamber 14 from the first air inlet 141. The diameter of the first air static pressure chamber 11 is larger than that of the first air intake pipeline 14, so that the air velocity of the air entering the first air static pressure chamber 11 is reduced and the pressure is increased, so that the air can enter the air pipeline 12 more evenly (the air flow channel of the biomass gas combustion device is formed between the inner wall of the air pipeline 12, the outer wall of the biomass gas branch pipeline 22, and the outer wall of the premixed gas pipeline 32). The air further evenly distributes the air flow and pressure through the rectifying holes 131 of the air flow equalizing orifice plate 13 to form a stable combustion-supporting air flow.

[0040] Biomass gas enters the biomass gas static pressure chamber 21 from the biomass gas inlet 241. The diameter of the biomass gas static pressure chamber 21 is larger than that of the biomass gas intake pipeline 24, so that the flow velocity of the biomass gas entering the biomass gas static pressure chamber 21 is reduced and the pressure is increased, so that the biomass gas can enter each biomass gas branch pipeline 22 evenly. Then, after passing through the biomass gas nozzle 23, the biomass gas generates swirl and is ejected from the biomass gas branch pipeline 22 in the form of a diffusion jet. The diffusion jet of the biomass gas can entrain the combustion-supporting air passing through the air flow equalizing orifice plate 13 and mix with it to achieve the purpose of efficient and full combustion. At the same time, after the diffusion jet combustion of the biomass gas, a high-temperature flue gas recirculation zone will be formed near the axial center position of the biomass gas nozzle 23 as a stable ignition source to ensure the stable combustion of the biomass gas flame.

[0041] When the natural gas combustion device is in operation, air enters the second air static pressure chamber 31 through the second air inlet 331. The diameter of the second air static pressure chamber 31 is larger than the pipe diameter of the second air inlet pipe 33, so that the air flow rate entering the second air static pressure chamber 31 is reduced and the pressure is increased, so that the air can enter the premixed gas pipe 32 evenly (the upstream section of the premixed gas pipe 32 is an air passage, the middle section of the premixed gas pipe 32 is a preliminary mixing passage of natural gas and air, and the downstream section of the premixed gas pipe 32 is a full mixing passage of air and natural gas). The air mixes with natural gas in the middle section of the premixed gas pipe 32.

[0042] Natural gas enters the natural gas pipe 41 through the natural gas inlet 411, flows out at the natural gas premixing nozzle 43 after passing through the tapered pipe 42, and is preliminarily mixed with the combustion-supporting air coming from the upstream of the premixed gas pipe 32. The natural gas nozzles 431 arranged in the circumferential direction of the natural gas premixing nozzle 43 can make the natural gas and air be preliminarily and evenly mixed. The mixed gas swirls at the natural gas premixing swirl vane 45 and is fully mixed during the downstream flow in the premixed gas pipe 32. The mixed gas passes through the anti-backfire orifice plate 34 (circular small holes are evenly arranged on the anti-backfire orifice plate 34, and the diameter of the small holes is smaller than the quenching distance of the corresponding flame of the premixed gas. That is, when the load is adjusted or the burner is shut down, when the flow rate of the mixed gas decreases and backfire occurs, the flame cannot continue to propagate through the circular small holes, effectively preventing the occurrence of backfire of the burner), and then enters the premixed gas nozzle 35. Most of the mixed gas swirls after passing through the premixed gas nozzle 35 and is ejected in the form of a diffused jet. The swirling mixed gas forms a high-temperature recirculation zone after combustion, which serves as a stable ignition source and can ensure the stability of the flame. At the same time, a small amount of mixed gas is ejected from the central hole 3521 of the premixed gas to form a central flame near the axis of the premixed gas nozzle 35 to further stabilize the combustion flame (the swirl channel of the premixed gas nozzle 35 is a spiral structure. When the flow rate of the mixed gas decreases and backfire occurs, the flame propagates upstream along the swirl channel to the premixed gas. During the process, heat is continuously dissipated through the premixed gas nozzle sleeve 351 and the swirl channel fins 353, so that the temperature of the backfired flame gradually decreases and finally is lower than the temperature for maintaining stable combustion, causing the flame to go out, which can effectively prevent the occurrence of backfire).

[0043] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple. For the relevant parts, reference can be made to the description in the method part.

[0044] The foregoing description of the disclosed embodiments enables those skilled in the art to practice or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dual-fuel low-nitrogen burner, characterized in that, It includes a biomass gas combustion device and a natural gas combustion device. The biomass gas combustion device includes a biomass gas combustion device air passage structure and a biomass gas combustion device gas passage structure. The natural gas combustion device includes a natural gas combustion device air passage structure and a natural gas combustion device gas passage structure. The biomass gas combustion device air passage structure, the biomass gas combustion device gas passage structure, the natural gas combustion device air passage structure, and the natural gas combustion device gas passage structure are sleeved and connected in sequence from outside to inside and arranged coaxially.

2. The dual-fuel low-nitrogen burner according to claim 1, wherein The biomass gas combustion device air passage structure includes a first air static pressure chamber, an air pipeline, an air flow equalizing orifice plate, and a first air intake pipeline. The end face of the first air static pressure chamber close to the downstream of the air flow is connected and communicated with the inlet end of the air pipeline, and the first air static pressure chamber and the air pipeline are arranged coaxially; the air flow equalizing orifice plate has a plurality of uniformly distributed rectifying holes, and the air flow equalizing orifice plate is fixed inside the air pipeline and is located on the side close to the outlet of the air pipeline; one end of the first air intake pipeline is connected and communicated with the side face of the first air static pressure chamber, and the first air intake pipeline is distributed radially along the first air static pressure chamber; the extended end of the first air intake pipeline has a first air inlet.

3. The dual-fuel low-nitrogen burner according to claim 2, characterized in that, The biomass gas combustion device gas passage structure includes a biomass gas static pressure chamber, a plurality of biomass gas branch pipelines, a plurality of biomass gas nozzles, and a biomass gas intake pipeline. The plurality of biomass gas branch pipelines are arranged annularly around the axis of the biomass gas static pressure chamber and are connected and communicated with the end face of the biomass gas static pressure chamber close to the downstream of the air flow; the end face of the first air static pressure chamber close to the upstream of the air flow has a first through hole corresponding to the position of the biomass gas branch pipeline, the air flow equalizing orifice plate has a second through hole corresponding to the position of the biomass gas branch pipeline, and the plurality of biomass gas branch pipelines are respectively inserted into the plurality of first through holes and the plurality of second through holes; the plurality of biomass gas nozzles are respectively installed at the outlet ends of the plurality of biomass gas branch pipelines; one end of the biomass gas intake pipeline is connected and communicated with the side face of the biomass gas static pressure chamber, and the biomass gas intake pipeline is distributed radially along the biomass gas static pressure chamber; the extended end of the biomass gas intake pipeline has a biomass gas inlet.

4. A dual-fuel low-nitrogen burner according to claim 3, characterized in that, Each of the biomass gas nozzles includes a plurality of gas nozzle sleeves and a sealing end plate. The plurality of gas nozzle sleeves are arranged at intervals in sequence from inside to outside and are arranged coaxially; a plurality of swirl vanes are provided between every two adjacent gas nozzle sleeves to form a swirl passage for the biomass gas; the sealing end plate is fixed at the outlet end of the innermost gas nozzle sleeve.

5. The dual-fuel low-nitrogen burner according to claim 3, characterized in that, The air passage structure of the natural gas combustion device includes a second air static pressure chamber, a premixed gas pipeline, a second air inlet pipeline, a backfire prevention orifice plate, and a premixed gas nozzle. The end face of the second air static pressure chamber close to the downstream of the air flow is connected and communicated with the inlet end of the premixed gas pipeline, and the second air static pressure chamber and the premixed gas pipeline are coaxially arranged. There is a third through hole in the center of both end faces of the biomass gas static pressure chamber, a fourth through hole in the end face of the first air static pressure chamber close to the upstream of the air flow, and a fifth through hole in the center of the air flow equalizing orifice plate. The premixed gas pipeline is sequentially inserted into the third through hole, the fourth through hole, and the fifth through hole. One end of the second air inlet pipeline is connected and communicated with the side surface of the second air static pressure chamber, and the second air inlet pipeline is radially distributed along the second air static pressure chamber. The extended end of the second air inlet pipeline has a second air inlet. The backfire prevention orifice plate and the premixed gas nozzle are sequentially installed at the outlet end of the premixed gas pipeline along the air flow direction.

6. The dual-fuel low-nitrogen burner according to claim 5, characterized in that, The backfire prevention orifice plate has a plurality of uniformly distributed round holes or grid holes with a hole diameter smaller than the flame extinction distance.

7. A dual-fuel low-nitrogen burner according to claim 5, characterized in that, The premixed gas nozzle includes a plurality of premixed gas nozzle sleeves and a premixed gas central plate. The plurality of premixed gas nozzle sleeves are sequentially arranged at intervals from the inside to the outside and are coaxially arranged. A plurality of swirl channel fins are provided between every two adjacent premixed gas nozzle sleeves to form a swirl channel for the premixed gas. The premixed gas central plate has a plurality of premixed gas central holes in the center. The premixed gas central plate is fixed at the outlet end of the innermost premixed gas nozzle sleeve.

8. The dual-fuel low-nitrogen burner according to claim 5, characterized in that, The gas passage structure of the natural gas combustion device includes a natural gas pipeline, a reducing pipe, a natural gas premixed nozzle, a cylinder, and natural gas premixed swirl vanes. The natural gas pipeline has a natural gas inlet. The natural gas pipeline, the reducing pipe, the natural gas premixed nozzle, and the cylinder are sequentially connected together and coaxially arranged along the air flow direction. The end face of the second air static pressure chamber close to the upstream of the air flow has a sixth through hole, and the natural gas pipeline is inserted into the sixth through hole. The natural gas premixed nozzle has a plurality of uniformly distributed natural gas nozzles along its circumferential direction. The two ends of the natural gas premixed swirl vanes are respectively fixedly connected to the cylinder and the inner wall of the premixed gas pipeline.

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