Burner special for ultralow-temperature and micro-pressure-drop LNG

Abstract

The utility model relates to the field of LNG (liquefied natural gas) combustion, in particular to a special ultralow-temperature micro-pressure-drop LNG combustor which comprises a combustor body. An expanding pipe is arranged at the bottom of the burner body, an air inlet pipe is arranged at the bottom of the expanding pipe, a heat insulation layer is movably connected to the outer surface of the air inlet pipe, a spiral piece is arranged in the air inlet pipe, the air injection ring is fixedly connected to the outer surface of the burner body, and a plurality of nozzles are fixedly connected to the inner side of the air injection ring. The rear end of the air injection ring is fixedly connected with a fixing pipe, and two porous ceramic flow equalizing plates are arranged in the combustor body. Pressure reduction is carried out through the stepped expanding pipe, meanwhile, preheated air is sprayed out from the air spraying ring, the preheated air is forcibly mixed with LNG in the combustor body, meanwhile, the double-layer porous ceramic flow equalizing plate ensures that fuel gas is completely gasified and evenly distributed, and the combustion efficiency is improved. The problems that a traditional LNG burner is uneven in mixing, unstable in flame and too large in pressure drop under the ultralow-temperature working condition are solved.

Description

Technical Field

[0001] This utility model relates to the field of LNG combustion, and in particular to a special burner for cryogenic and low-pressure-drop LNG. Background Technology

[0002] LNG-specific burners are high-efficiency and environmentally friendly industrial combustion equipment designed specifically for liquefied natural gas. They employ premixed or diffusion combustion technology to ensure thorough mixing of natural gas and air, achieving stable combustion and efficient energy release. Their core features include low nitrogen oxide emissions, high combustion efficiency, cryogenic materials adapted to the -162℃ characteristics of LNG, and an intelligent control system for precise air-fuel ratio adjustment. They are widely used in power plants, chemical plants, marine propulsion, and urban heating, combining safety, reliability, and clean energy advantages to help achieve carbon reduction goals.

[0003] Because of the extremely low temperature of LNG, the combustion of ultra-low temperature LNG burners is unstable at low temperatures, resulting in flame flickering, partial flameout, or incomplete combustion. This leads to intense heat exchange when the gas mixes with air, causing the temperature of the mixture to drop sharply below the flammability limit. The gas density changes greatly and the flow field distribution is uneven in the low-temperature environment, which further exacerbates the tendency of flame de-ignition. This not only reduces combustion efficiency but also increases unburned methane emissions, and in severe cases, may even lead to the risk of deflagration.

[0004] Therefore, in response to the above-mentioned problems caused by the extremely low temperature of LNG, the unstable combustion of cryogenic LNG burners during low-temperature combustion, resulting in flame flickering, partial flameout, or incomplete combustion, which leads to intense heat exchange when the gas and air are mixed, and the temperature of the mixed gas drops sharply below the combustible limit, not only reducing combustion efficiency but also increasing unburned methane emissions, and in severe cases even causing the risk of deflagration, a dedicated cryogenic, low-pressure-drop LNG burner can be designed. Utility Model Content

[0005] To overcome the problem that due to the extremely low temperature of LNG, the ultra-low temperature LNG burner is unstable during low-temperature combustion, resulting in flame flickering, partial flameout, or incomplete combustion, which leads to intense heat exchange when the gas and air are mixed, causing the temperature of the mixture to drop sharply below the combustible limit.

[0006] The technical solution of this utility model is as follows: a cryogenic, low-pressure-drop LNG-specific burner, including a burner body; and an air injection ring. An expansion pipe is provided at the bottom of the burner body, and an air inlet pipe is provided at the bottom of the expansion pipe. An insulation layer is movably connected to the outer surface of the air inlet pipe, and a spiral blade is provided inside the air inlet pipe. An air injection ring is fixedly connected to the outer surface of the burner body, and multiple nozzles are fixedly connected to the inner side of the air injection ring. A fixed pipe is fixedly connected to the rear end of the air injection ring, and two porous ceramic flow equalization plates are provided inside the burner body.

[0007] Preferably, when LNG enters the burner, it is premixed by swirling through the spiral blades in the intake pipe, and then depressurized by the stepped expansion pipe. At the same time, preheated air enters the air injection ring from the fixed pipe and is then ejected from the nozzle, forcing the preheated air to mix with LNG in the burner body. Meanwhile, the double-layer porous ceramic flow equalization plate ensures complete gasification and uniform distribution of the fuel gas, ultimately achieving stable combustion at low temperatures in the burner body. This prevents uneven mixing, unstable flame, and excessive pressure drop in the LNG burner under ultra-low temperature conditions.

[0008] As a preferred option, the expansion pipe uses a three-stage expansion design, and a flange is fixedly connected to the bottom of the intake pipe.

[0009] Preferably, a sleeve is provided on the outer surface of the burner body, and the burner body is fixedly connected to the top of the sleeve.

[0010] Preferably, the burner body has an inner honeycomb plate inside, and the surface of the inner honeycomb plate has multiple small holes.

[0011] Preferably, the upper end of the burner body is provided with an outer honeycomb plate, and the surface of the outer honeycomb plate is provided with multiple large holes.

[0012] Preferably, the outer surface of the burner body is provided with five petal-shaped plates, and the surface of the petal-shaped plates is provided with multiple large holes.

[0013] Preferably, four support rods are fixedly connected to the top of the outer honeycomb panel, and flame stabilizing plates are fixedly connected to the top of the support rods.

[0014] The beneficial effects of this utility model are:

[0015] When LNG enters the burner, it is premixed by swirling through the spiral blades in the intake pipe. Then, it is depressurized by passing through a stepped expansion pipe. At the same time, preheated air enters the air injection ring from the fixed pipe and is then ejected from the nozzle, forcing the preheated air to mix with the LNG in the burner body. Meanwhile, the double-layer porous ceramic flow equalization plate ensures complete gasification and uniform distribution of the fuel gas. Finally, stable combustion at low temperature is achieved in the burner body, preventing uneven mixing, unstable flame, and excessive pressure drop in ultra-low temperature conditions. Attached Figure Description

[0016] Figure 1 The diagram shown is a three-dimensional structural schematic of this utility model;

[0017] Figure 2 The diagram shown is a three-dimensional side sectional view of the present invention.

[0018] Figure 3 The diagram shown is a three-dimensional rear cross-sectional view of the outer honeycomb panel of this utility model.

[0019] Figure 4 The diagram shown is a three-dimensional lower cross-sectional view of the present invention.

[0020] Figure 5 The diagram shown is a three-dimensional top cross-sectional view of the present invention.

[0021] Explanation of reference numerals in the attached drawings: 1. Burner body; 2. Inlet pipe; 3. Spiral blade; 4. Insulation layer; 5. Expander pipe; 6. Air injection ring; 7. Fixed pipe; 8. Nozzle; 9. Porous ceramic flow equalization plate; 10. Flange; 11. Burner body; 12. Sleeve; 13. Inner honeycomb plate; 14. Outer honeycomb plate; 15. Petal-shaped plate; 16. Support rod; 17. Flame stabilizing plate. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Please see Figures 2-5 This utility model provides an embodiment: an ultra-low temperature, low-pressure-drop LNG-specific burner includes a burner body 1; it also includes an air injection ring 6. An expansion pipe 5 is provided at the bottom of the burner body 1, and an air inlet pipe 2 is provided at the bottom of the expansion pipe 5. An insulation layer 4 is movably connected to the outer surface of the air inlet pipe 2, and a spiral blade 3 is provided inside the air inlet pipe 2. An air injection ring 6 is fixedly connected to the outer surface of the burner body 1, and multiple nozzles 8 are fixedly connected to the inner side of the air injection ring 6. A fixing pipe 7 is fixedly connected to the rear end of the air injection ring 6. Two multi-nozzle nozzles 8 are provided inside the burner body 1. The porous ceramic flow equalization plate 9 allows LNG to enter the burner. When LNG enters the burner, it is premixed by the spiral blades 3 in the air inlet pipe 2. Then, the LNG is depressurized by the stepped expansion pipe 5. At the same time, preheated air enters the air injection ring 6 from the fixed pipe 7 and is then sprayed out from the nozzle 8. This forces the preheated air to mix with LNG in the burner body 1. Meanwhile, the double-layer porous ceramic flow equalization plate 9 ensures complete gasification and uniform distribution of the fuel gas. Finally, stable combustion at low temperature is achieved in the burner body 1, so that the LNG burner will not experience uneven mixing, unstable flame, or excessive pressure drop under ultra-low temperature conditions.

[0024] Please see Figures 1-3In this embodiment, the expansion pipe 5 uses a three-stage expansion design. The bottom of the inlet pipe 2 is fixedly connected to a flange 10. The inlet pipe 2 is fixed to the flare system pipeline through the flange 10 and external bolts. The expansion angle of each stage of the expansion pipe 5 is 12°, and the length of the transition section between stages is 1.5 times the pipe diameter, gradually reducing the flow velocity. At the same time, the inner surface is polished to reduce flow resistance. The outer surface of the burner body 1 is provided with a sleeve 12. The top of the sleeve 12 is fixedly connected to the burner body 11. The burner body 11 is fixed to the burner body 1 through the sleeve 12. After the LNG is fully mixed with the preheated air, it enters the burner body 11. The inside of the burner body 11 is provided with an inner honeycomb plate 13. The surface of the inner honeycomb plate 13 is provided with multiple small holes. The hole diameter of the inner honeycomb plate 13 is 0.1 mm, the hole spacing is 1 mm, and it is inclined at 60°. The LNG is premixed in the inner layer to reduce NOx.

[0025] Please see Figures 1-2 In this embodiment, an outer honeycomb plate 14 is provided at the upper end of the burner body 11. The surface of the outer honeycomb plate 14 is provided with multiple large holes with a diameter of 0.5 mm and a spacing of 2 mm. LNG is vertically injected to enrich the outer layer and improve the burnout rate. Five petal-shaped plates 15 are provided on the outer surface of the burner body 11. The surface of the petal-shaped plates 15 is provided with multiple large holes. The petal-shaped plates 15 increase the combustion area. Four support rods 16 are fixedly connected to the top of the outer honeycomb plate 14. A flame stabilizing plate 17 is fixedly connected to the top of the support rods 16. The flame stabilizing plate 17 is made of low-temperature resistant materials such as SiC ceramic, which absorbs the heat of high-temperature flue gas and conducts it in the reverse direction to the root of the flame to maintain the temperature of the low-temperature gas ignition zone.

[0026] During operation, this cryogenic, low-pressure-drop LNG burner allows LNG to enter the burner. The LNG is premixed by swirling flow generated by the spiral vanes 3 within the inlet pipe 2, and then depressurized through the stepped expansion pipe 5. Simultaneously, preheated air enters the air injection ring 6 from the fixed pipe 7 and is ejected from the nozzle 8, forcibly mixing the preheated air with the LNG within the burner body 1. A double-layer porous ceramic flow equalization plate 9 ensures complete vaporization and uniform distribution of the fuel gas, ultimately achieving stable combustion at low temperatures within the burner body 1. This solves the problems of uneven mixing, unstable flame, and excessive pressure drop in traditional LNG burners under cryogenic conditions. The inlet pipe 2 is fixed to the flare system piping via flange 10 and external bolts. Each stage of the expansion pipe 5 has an expansion angle of 12°. The length of the interstage transition section is 1.5 times the pipe diameter, gradually reducing the flow velocity. At the same time, the inner surface is polished to reduce flow resistance. The burner body 11 is fixed to the burner body 1 through the sleeve 12. LNG is fully mixed with preheated air and then enters the burner body 11. The pores on the inner honeycomb plate 13 have a diameter of 0.1 mm and a spacing of 1 mm, and are inclined at 60°. LNG is premixed in the inner layer to reduce NOx. The pores on the outer honeycomb plate 14 have a diameter of 0.5 mm and a spacing of 2 mm. LNG is injected vertically and enriched in the outer layer to improve the burnout rate. The petal-shaped plate 15 increases the combustion area. The flame stabilizing plate 17 uses low-temperature resistant materials such as SiC ceramic to absorb the heat of high-temperature flue gas and conduct it in the reverse direction to the flame root, maintaining the temperature of the low-temperature gas ignition zone.

[0027] Through the above steps, this cryogenic, low-pressure-drop LNG burner, when LNG enters the burner, generates swirling premixed LNG through the spiral blades 3 in the air inlet pipe 2, and then reduces the pressure through the stepped expansion pipe 5. At the same time, preheated air enters the air injection ring 6 from the fixed pipe 7 and is then sprayed out from the nozzle 8, so that the preheated air is forcibly mixed with LNG in the burner body 1. Meanwhile, the double-layer porous ceramic flow equalization plate 9 ensures complete gasification and uniform distribution of the gas, and finally achieves stable combustion at low temperature in the burner body 1, solving the problems of uneven mixing, unstable flame and excessive pressure drop of traditional LNG burners under cryogenic conditions.

Claims

1. A cryogenic, low-pressure-drop LNG burner, comprising a burner body (1); characterized in that: It also includes an air injection ring (6), an expansion pipe (5) at the bottom of the burner body (1), an air inlet pipe (2) at the bottom of the expansion pipe (5), an insulation layer (4) movably connected to the outer surface of the air inlet pipe (2), a spiral blade (3) inside the air inlet pipe (2), an air injection ring (6) fixedly connected to the outer surface of the burner body (1), multiple nozzles (8) fixedly connected to the inner side of the air injection ring (6), a fixed pipe (7) fixedly connected to the rear end of the air injection ring (6), and two porous ceramic flow equalization plates (9) inside the burner body (1).

2. The cryogenic, low-pressure-drop LNG burner according to claim 1, characterized in that: The expansion pipe (5) uses a three-stage expansion design, and the bottom of the air inlet pipe (2) is fixedly connected to a flange (10).

3. The cryogenic, low-pressure-drop LNG burner according to claim 1, characterized in that: A sleeve (12) is provided on the outer surface of the burner body (1), and a burner body (11) is fixedly connected to the top of the sleeve (12).

4. The cryogenic, low-pressure-drop LNG burner according to claim 1, characterized in that: The burner body (11) has an inner honeycomb plate (13) inside, and the surface of the inner honeycomb plate (13) has multiple small holes.

5. The cryogenic, low-pressure-drop LNG burner according to claim 1, characterized in that: The upper end of the burner body (11) is provided with an outer honeycomb plate (14), and the surface of the outer honeycomb plate (14) is provided with multiple large holes.

6. The cryogenic, low-pressure-drop LNG burner according to claim 1, characterized in that: The outer surface of the burner body (11) is provided with five petal-shaped plates (15), and the surface of the petal-shaped plates (15) is provided with multiple large holes.

7. The cryogenic, low-pressure-drop LNG burner according to claim 5, characterized in that: Four support rods (16) are fixedly connected to the top of the outer honeycomb panel (14), and flame stabilizing plate (17) is fixedly connected to the top of the support rods (16).

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