Natural gas hydrogen-doped turbulent burner

Abstract

In order to solve the problems of low combustion efficiency caused by different combustion efficiencies of natural gas and hydrogen and safety accidents caused by hydrogen backdraft of a traditional hydrogen-doped natural gas turbulent burner, the hydrogen-doped natural gas turbulent burner comprises a porous hydrogen inlet, a plurality of natural gas inlets, a cyclone and a plurality of secondary air inlets, the secondary air inlet, the natural gas inlet and the hydrogen inlet are sequentially arranged from outside to inside, and the cyclone is mounted between the natural gas inlet and the hydrogen inlet; a plurality of cylindrical straight holes are formed in the top of the hydrogen inlet and are distributed in a concentric circle array. By means of mixed combustion of natural gas and hydrogen, the combustion efficiency is improved, generation of nitric oxide is reduced, and the efficient and clean combustion effect is achieved; the combustion rate of the natural gas is increased through rapid combustion of hydrogen, flame robustness is good, hydroxyl released in the hydrogen combustion process can effectively reduce combination of nitrogen elements in air and oxygen, and generation of nitric oxide is inhibited. The invention belongs to the technical field of energy and chemical engineering.

Description

Technical Field

[0001] The present invention relates to a burner, in particular to a natural gas hydrogen-blended swirl burner, which belongs to the energy and chemical technology field. Background Art

[0002] As the global energy mix shifts toward a low-carbon future, natural gas hydrogen-blended combustion technology has become a critical bridge between traditional fossil fuels and renewable energy. Natural gas is increasingly prominent as a transitional energy source, and hydrogen blending can significantly reduce its carbon intensity—every 10% natural gas replacement reduces CO2 emissions by approximately 6%-12%. Since the production, storage, transportation, and combustion of pure hydrogen are still in the research phase, the application costs are significant. By leveraging operational experience from coal chemical industry, the storage, transportation, and combustion of low-proportion hydrogen blends can be achieved. The rise of natural gas hydrogen blending technology is closely linked to global climate governance goals and the restructuring of the energy system. Driven by the "dual carbon" strategy, achieving dual carbon goals can only be achieved by improving the efficiency of fossil energy utilization or adopting non-fossil energy alternatives.

[0003] Due to the considerable difference in physical properties between hydrogen and natural gas, my country's current hydrogen production is not enough to completely replace natural gas. At the same time, the cost of hydrogen preparation is extremely high. In terms of combustion stability, the combustion speed of hydrogen is 7-8 times that of methane, which can easily cause flame oscillation and even flashback, resulting in unstable burner operation. It is extremely dangerous to convert existing natural gas burners to hydrogen, but the cost of replacing them all with hydrogen burners is extremely high. Due to the excessive combustion speed of hydrogen, the natural gas and hydrogen in the traditional natural gas hydrogen swirl burner are directly injected into the furnace and mixed with the swirl air for combustion, which is prone to flashback and is accompanied by a large amount of thermal NO x To solve the above problems, a natural gas hydrogen-blended burner was developed by combining the combustion characteristics of natural gas and hydrogen. Summary of the Invention

[0004] The present invention aims at the combustion characteristics of natural gas and hydrogen. In order to solve the problems of low combustion efficiency and safety accidents caused by hydrogen backfire caused by the different combustion efficiencies of natural gas and hydrogen in traditional natural gas hydrogen blended swirl burners, the present invention proposes a natural gas hydrogen blended swirl burner.

[0005] The technical solution adopted by the present invention to solve the above problems is: The present invention provides a natural gas-hydrogen-blended swirl burner, comprising a hydrogen inlet, multiple natural gas inlets, a swirler, and multiple secondary air inlets. The secondary air inlet, natural gas inlet, and hydrogen inlet are arranged sequentially from the outside to the inside, and the swirler is installed between the natural gas inlet and the hydrogen inlet. The top of the hydrogen inlet is provided with multiple cylindrical straight holes, and the multiple cylindrical straight holes are distributed in a concentric circle array.

[0006] Furthermore, the concentric circle array is 3-5 circles, and the radial spacing between adjacent concentric circle arrays is 1.5-2 times the aperture.

[0007] Furthermore, each circle of the concentric circle array is provided with a cylindrical straight hole, and the aperture of each cylindrical straight hole is: The axial spacing between two adjacent cylindrical straight holes is: Furthermore, the hydrogen inlet is made of a hydrogen-resistant alloy such as 316L stainless steel and the outer surface is sprayed with a high-temperature resistant coating containing potassium.

[0008] Furthermore, the multiple secondary air inlets are evenly distributed along the circumference, with a number of 6-8, and each secondary air inlet is inclined inwardly toward the burner axis.

[0009] Furthermore, the inward inclination angle (a) of each secondary air inlet is 13-17 degrees, which concentrates the flame and replenishes the oxygen required for combustion.

[0010] Furthermore, the inward inclination angle a of each secondary air inlet is 15°.

[0011] Furthermore, the multiple natural gas inlets are evenly distributed on the outside of the hydrogen inlet along the circumferential direction, and their structure is the same as that of the hydrogen inlet 1.

[0012] Furthermore, the burner also includes a check valve, which is installed on the hydrogen inlet pipe of the hydrogen inlet to prevent hydrogen from backfiring.

[0013] Furthermore, the cyclone includes a plurality of blades, which are evenly distributed along the circumference, and the inclination angle of each blade is 55-65°; the number of blades is 6-12. The beneficial effects of the present invention are: 1. The present invention adopts a porous structure through the hydrogen inlet, and disperses the hydrogen jet through a plurality of cylindrical straight holes distributed in a concentric circle array, thereby reducing the local flame speed and achieving the tempering flame retardant function; 2. The present invention achieves enhanced combustion efficiency, shortened combustion time, concentrated flame, and enhanced flame center temperature by tilting the secondary air inlet inward by 15 degrees; 3. Since hydrogen burns too fast, it is easy to backfire. The present invention prevents the occurrence of hydrogen backfire accidents by providing a check valve on the hydrogen inlet pipe; 4. The mixed combustion of natural gas and hydrogen in the present invention achieves efficient and clean combustion; the hydroxyl groups released by the combustion of hydrogen can effectively inhibit the reaction between nitrogen and oxygen atoms, significantly reducing the generation of nitrogen oxides during the combustion process.

[0014] 5. In the present invention, hydrogen enters the porous hydrogen inlet through a check valve and is dispersed into multiple microjets, and natural gas is ejected from multiple annular natural gas inlets; air is sandwiched between the hydrogen and natural gas inlets through a cyclone, forming a strong vortex and providing part of the oxygen required for combustion of the combustible gas; secondary air is injected at an axial angle of 15° to compress the flame plume, increase combustion power and achieve stable combustion; the hydrogen is injected into the furnace through the porous hydrogen burner nozzle, which increases the instantaneous pressure of the hydrogen when it is injected into the furnace, preventing the flame from flashing back and reducing the flashback risk to more than 80%. The check valve installed on the pipeline can completely prevent the occurrence of hydrogen flashback accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 is a schematic cross-sectional view of the hydrogen inlet of the present invention; Figure 3 Schematic diagram of the inclination angle of the secondary air inlet of the present invention; Figure 4 It is a structural diagram of the cyclone blade angle of the present invention; Figure 5 It is a system diagram of the present invention.

[0016] In the figure: 1, hydrogen inlet; 1-1, cylindrical straight hole; 2. Natural gas inlet; 3. Cyclone; 4. Multiple secondary air inlets; 5. Ignition device; 6. Check valve. DETAILED DESCRIPTION

[0017] Specific implementation: This embodiment of the invention is a natural gas hydrogen-blended swirl burner, such as Figure 1 As shown, it includes a hydrogen inlet 1, multiple natural gas inlets 2, a cyclone 3 and multiple secondary air inlets 4. The secondary air inlet 4, the natural gas inlet 2 and the hydrogen inlet 1 are arranged in sequence from the outside to the inside, and the cyclone 3 is installed between the natural gas inlet 2 and the hydrogen inlet 1.

[0018] like Figure 2 As shown, the top of the hydrogen inlet 1 is provided with multiple cylindrical straight holes 1-1, arranged in a concentric array. The array consists of three to five concentric circles, with the radial spacing between adjacent concentric circles being 1.5 to 3 times the aperture diameter. Each concentric circle has 6 to 16 cylindrical straight holes 1-1, each with a diameter no greater than 10 mm (the specific value is determined based on the burner's power calculations). The axial spacing between two adjacent cylindrical straight holes 1-1 is 1.5 to 3 times the aperture diameter. The porous structure of the hydrogen inlet 1 disperses the hydrogen jet, reducing local flame speed and blocking flashback paths.

[0019] Preferably, the hydrogen inlet 1 is made of a hydrogen-resistant alloy (such as 316L stainless steel) and the outer surface is sprayed with a high-temperature resistant coating layer containing potassium.

[0020] Preferably, the multiple natural gas inlets 2 are evenly distributed on the outside of the hydrogen inlet 1 along the circumferential direction, and their structure is the same as that of the hydrogen inlet 1.

[0021] like Figure 3 As shown, the multiple secondary air inlets 4 are evenly distributed along the circumference, numbering 6-8. Each secondary air inlet 4 is tilted inwardly toward the burner axis. The inward tilt angle a of each secondary air inlet 4 is 13-17°, preferably 15°. The tilted secondary air inlets 4 compress the plume, focus the flame, enhance premixing of hydrogen, natural gas, and air, strengthen combustion, improve combustion efficiency, and reduce nitrogen oxide generation.

[0022] like Figure 4 As shown, the cyclone 3 includes multiple blades evenly distributed around the circumference. Each blade has an inclination angle of 55-65°, preferably 60°, and the number of blades is 6-12. Increasing the inclination angle of the cyclone blades increases the swirl intensity, promotes uniform mixing of natural gas, hydrogen, and air, and suppresses localized high-temperature zones.

[0023] like Figure 5 As shown, the burner further includes a check valve 5 , which is installed on the hydrogen inlet pipe of the hydrogen inlet 1 to prevent hydrogen backfire.

[0024] The burner ignition process is as follows: Since hydrogen burns with a colorless flame, sodium salt is applied to the hydrogen inlet 1, and the flame appears yellow under the flame color reaction. Hydrogen burns quickly and has a high calorific value. To this end, the hydrogen and swirl air in the center are first turned on, and the hydrogen is ignited by the igniter 5 to increase the furnace temperature. When the furnace temperature reaches the natural gas combustion temperature, the natural gas and secondary air are turned on. When shutting down, the hydrogen is turned off first, then the natural gas, and finally the air. The present invention can achieve flexible peak regulation of the burner. When the burner load requirement is low, the hydrogen burner can be turned on alone. When the burner load increases, the natural gas and secondary air volume can be appropriately increased to achieve stable combustion.

[0025] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement of the above embodiments made according to the technical essence of the present invention, within the spirit and principles of the present invention, without departing from the content of the technical solution of the present invention, shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A natural gas hydrogen-blended swirl burner, characterized in that: include: A hydrogen inlet (1), a plurality of natural gas inlets (2), a cyclone (3) and a plurality of secondary air inlets (4), wherein the secondary air inlet (4), the natural gas inlet (2) and the hydrogen inlet (1) are arranged in sequence from the outside to the inside, and the cyclone (3) is installed between the natural gas inlet (2) and the hydrogen inlet (1); a plurality of cylindrical straight holes (1-1) are provided on the top of the hydrogen inlet (1), and the plurality of cylindrical straight holes (1-1) are distributed in a concentric circle array.

2. The natural gas hydrogen-blended swirl burner according to claim 1, characterized in that: The concentric circle arrays are 3-5 circles, and the radial spacing between adjacent concentric circle arrays is 1.5-2 times the hole diameter.

3. The natural gas hydrogen-blended swirl burner according to claim 2, characterized in that: Each circle of the concentric circle array is provided with 6-16 cylindrical straight holes (1-1), the diameter of each cylindrical straight hole (1-1) is not greater than 10 mm, and the axial spacing between two adjacent cylindrical straight holes (1-1) is 1.5-2 times the hole diameter.

4. The natural gas hydrogen-blended swirl burner according to claim 1, characterized in that: The hydrogen inlet (1) is made of hydrogen-resistant alloy.

5. The natural gas hydrogen-blended swirl burner according to claim 1, characterized in that: The multiple secondary air inlets (4) are evenly distributed along the circumference, with a number of 6-8, and each secondary air inlet (4) is inclined inwardly toward the burner axis.

6. The natural gas hydrogen-blended swirl burner according to claim 1, characterized in that: The inward inclination angle (a) of each secondary air inlet (4) is 13-17°.

7. The natural gas hydrogen-blended swirl burner according to claim 1, characterized in that: The inward inclination angle (a) of each secondary air inlet (4) is 15°.

8. The natural gas hydrogen-blended swirl burner according to claim 1, characterized in that: The multiple natural gas inlets (2) are evenly distributed on the outside of the hydrogen inlet (1) along the circumferential direction, and their structure is the same as that of the hydrogen inlet (1).

9. The natural gas hydrogen-blended swirl burner according to claim 1, characterized in that: The burner further comprises a stop valve (5), which is mounted on the hydrogen inlet pipe of the hydrogen inlet (1).

10. The natural gas hydrogen-blended swirl burner according to claim 1, characterized in that: The cyclone (3) comprises a plurality of blades, which are evenly distributed along the circumference, and the inclination angle of each blade is 55-65°; the number of blades is 6-12.

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