A plasma-enhanced direct-injection liquid ammonia atomizing nozzle and a liquid ammonia burner

Abstract

The present invention discloses a plasma-enhanced direct-injection liquid ammonia atomizing nozzle and a liquid ammonia burner, which belong to the field of liquid fuel combustion. The plasma-enhanced direct-injection liquid ammonia atomizing nozzle comprises a liquid ammonia channel, a compressed air channel, an atomizing channel, a secondary air channel and a heating component, wherein the outlet end of the compressed air channel and the outlet end of the liquid ammonia channel are both connected to the atomizing channel; the heating component comprises a high-voltage electrode, a ground electrode and a central air channel, the ground electrode is arranged on the outside of the high-voltage electrode, and the outlet of the central air channel faces the discharge area formed by the high-voltage electrode and the ground electrode; the discharge area formed by the high-voltage electrode and the ground electrode is close to the liquid ammonia channel; a ground electrode hole is arranged on the ground electrode near the liquid ammonia channel. The present invention realizes the self-evaporation of the preheated part of the liquid ammonia through a small plasma flame, realizes the efficient atomization and stable combustion of large-flow liquid ammonia, and reduces the consumption of the atomizing medium.

Description

Technical Field

[0001] The invention belongs to the field of liquid fuel combustion, and in particular relates to a plasma-enhanced direct-injection liquid ammonia atomizing nozzle and a liquid ammonia burner. Background Art

[0002] Using renewable energy to produce green hydrogen and artificially synthesize green ammonia can store unstable energy sources such as wind power and photovoltaics in the form of chemical energy. As a zero-carbon fuel, green ammonia contains a high proportion of hydrogen, has a high calorific value, and is easy to store and transport. It can be used in coal-fired power plant boilers to generate electricity, achieving the goal of carbon reduction and long-term, cross-regional energy storage in the power industry. It is conducive to building a new power system with new energy as the main body, thermal power units for peak regulation, and energy storage facilities as supporting facilities. Ammonia is usually stored and transported in liquid form. When it is burned as a fuel, it is usually first gasified into ammonia gas, and then introduced into the furnace to burn with other fuels. This method has two disadvantages: first, the ammonia supply system needs to be equipped with a large-capacity ammonia evaporator and a large-diameter ammonia delivery pipeline, and the equipment investment is large; second, because the energy density of gas fuel is much smaller than that of liquid fuel, the cross-sectional area of ​​the gas fuel burner is much larger than that of liquid fuel when the thermal power is the same, resulting in tight space for the layout of the boiler burner, which is not conducive to the large-proportion ammonia combustion transformation of the boiler.

[0003] Experiments have shown that direct injection of liquid ammonia into a high-temperature furnace can achieve stable and efficient combustion. Therefore, the direct use of liquid ammonia burners is conducive to saving investment and improving the flexibility of boiler burner layout. As an important component of a liquid fuel burner, the structural design of the atomizing nozzle has a decisive influence on the overall performance of the burner. The addition of a liquid ammonia burner to the boiler needs to be consistent with the type of pulverized coal burner. Pulverized coal burners are divided into direct flow and swirl. The former is used for tangential combustion boilers, and the latter is used for counter-combustion boilers. Liquid atomizing nozzles mainly include pressure atomization and medium atomization. Pressure atomization mostly uses centrifugal nozzles, which are suitable for counter-combustion boilers. Medium atomization is direct injection, but the atomization flow rate is small and the atomization medium consumption is large. Therefore, a direct injection liquid ammonia atomizing nozzle suitable for large flow liquid ammonia is required. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a plasma-enhanced direct-injection liquid ammonia atomizing nozzle, which forms a small plasma flame by designing a heating component to realize the self-evaporation of the preheated part of the liquid ammonia, thereby achieving efficient atomization and stable combustion of large-flow liquid ammonia while reducing the consumption of the atomizing medium.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A plasma-enhanced direct-injection liquid ammonia atomizing nozzle, comprising a liquid ammonia channel, a compressed air channel, an atomizing channel, a secondary air channel and a heating component, wherein the heating component is used to heat the liquid ammonia channel to gasify the liquid ammonia; wherein the outlet end of the compressed air channel and the outlet end of the liquid ammonia channel are both connected to the atomizing channel; the heating component comprises a high-voltage electrode, a ground electrode and a central air channel, wherein the ground electrode is arranged outside the high-voltage electrode, and the outlet of the central air channel faces the discharge area formed by the high-voltage electrode and the ground electrode; the discharge area formed by the high-voltage electrode and the ground electrode is close to the liquid ammonia channel; a ground electrode hole is arranged on the ground electrode at a position close to the liquid ammonia channel;

[0007] The liquid ammonia in the liquid ammonia channel is partially gasified and mixed with the compressed air before being sprayed out from the atomization channel.

[0008] Wherein, the distance between the front edge of the head of the high-voltage electrode and the ground electrode is less than 5 mm.

[0009] Wherein, a cyclone ring is arranged at the outlet of the central wind channel.

[0010] Wherein, a swirl ring hole is arranged on the swirl ring.

[0011] Among them, the swirl ring hole has a deflection angle and a swirl number of 0.4~0.45;

[0012] Wherein, the ground electrode hole has a deflection angle and a swirl number of 0.3~0.35.

[0013] Wherein, the deflection directions of the cyclone ring hole and the ground electrode hole are opposite.

[0014] Wherein, the high voltage electrode is a rod-shaped high voltage electrode;

[0015] And / or, the ground electrode is a conical ground electrode.

[0016] Wherein, the half apex angle β of the conical ground electrode is 30 degrees to 45 degrees.

[0017] Wherein, the central wind channel, the liquid ammonia channel and the compressed air channel are coaxially arranged, and the liquid ammonia channel is located between the central wind channel and the compressed air channel.

[0018] The liquid ammonia outer wall of the liquid ammonia channel is composed of a front section of the liquid ammonia outer wall and a rear section of the liquid ammonia outer wall. The front section of the liquid ammonia outer wall is partially sleeved on the outside of the rear section of the liquid ammonia outer wall. The front section of the liquid ammonia outer wall is in an angled form, and a variable cross-section channel is formed between the front section of the liquid ammonia outer wall and the ground electrode.

[0019] And / or, the outer wall of the compressed air channel consists of a front section of the compressed air outer wall and a rear section of the compressed air outer wall, the front section of the compressed air outer wall is partially sleeved inside the rear section of the compressed air outer wall, wherein the front section of the compressed air outer wall is in an angled form, and a variable cross-section channel is formed between the front section of the compressed air outer wall and the front section of the liquid ammonia outer wall.

[0020] Wherein, the tail of the front section of the liquid ammonia outer wall is connected to the first push rod screw, and the tail of the first push rod screw is connected to the first servo motor;

[0021] And / or, the tail of the front section of the compressed air outer wall is connected to the second push rod screw, and the tail of the second push rod screw is connected to the second servo motor.

[0022] Wherein, the atomization expansion angle α of the atomization channel is 0 degrees to 15 degrees.

[0023] Wherein, the secondary air channel and the liquid ammonia channel are coaxially arranged.

[0024] A liquid ammonia burner comprises the above-mentioned plasma-enhanced direct-injection liquid ammonia atomizing nozzle.

[0025] The liquid ammonia pressure in the liquid ammonia burner is 0.8 MPa to 1.0 MPa, and the compressed air pressure is 0.05 to 0.1 MPa higher than the liquid ammonia pressure.

[0026] Among them, the ratio of liquid ammonia flow to compressed air flow is 1:3~1:5;

[0027] Among them, the air volume ratio of central air, compressed air and secondary air is 5~10:60~70:20~30.

[0028] The beneficial effects of the present invention are:

[0029] (1) The present invention designs a heating component to realize the self-evaporation of the preheated part of the liquid ammonia, which can achieve efficient atomization and stable combustion of large-flow liquid ammonia while reducing the consumption of the atomizing medium.

[0030] (2) The present invention uses low-power plasma continuous discharge to ionize the central wind gas, ignite a small amount of liquid ammonia (ammonia gas) to form a stable ammonia gas flame, heat the ground electrode and the metal wall of the atomization channel through which the liquid ammonia flows, and promote the evaporation of part of the liquid ammonia into gas in the atomization channel. The gas and the compressed air serve as the atomization medium for the liquid ammonia, which reduces the amount of liquid ammonia that needs to be atomized and increases the flow rate of the atomization medium through the self-evaporation of the liquid ammonia, thereby reducing the consumption of compressed air.

[0031] (3) The present invention uses liquid ammonia to reflux high-temperature flue gas in an annular spray, and uses the high-temperature flue gas to heat the liquid ammonia, thereby achieving partial self-evaporation of the liquid ammonia. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a cross-sectional view of a plasma-enhanced direct-injection liquid ammonia atomizing nozzle of the present invention;

[0033] Figure 2 It is a front view of a plasma-enhanced direct-injection liquid ammonia atomizing nozzle of the present invention;

[0034] Figure 3 The figure is a rear view of a plasma-enhanced direct-injection liquid ammonia atomizing nozzle according to the present invention.

[0035] The accompanying drawings are marked as follows: 1-high voltage electrode, 1-1-high voltage electrode head, 2-ground electrode, 3-ground electrode hole, 4-central air inlet, 5-liquid ammonia inlet, 6-compressed air inlet, 7-secondary air inlet, 8-central air channel, 9-liquid ammonia channel, 10-compressed air channel, 11-secondary air channel, 12-atomization channel, 13-front section of liquid ammonia outer wall, 14-rear section of liquid ammonia outer wall; 15-front section of compressed air outer wall, 16-rear section of compressed air outer wall, 17-first push rod screw, 18-second push rod screw, 19-first servo motor, 20-second servo motor, 21-swirl ring, 22-inner cylinder support block, 23-outer cylinder support block, α-atomization expansion angle, β-half apex angle of conical ground electrode. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] See also Figure 1 A plasma-enhanced direct-injection liquid ammonia atomizing nozzle comprises a liquid ammonia channel 9, a compressed air channel 10, a secondary air channel 11, an atomizing channel 12 and a heating component, wherein the heating component is used to heat the liquid ammonia channel 9 to vaporize the liquid ammonia; wherein the outlet end of the compressed air channel 10 and the outlet end of the liquid ammonia channel 9 are both connected to the atomizing channel 12; the liquid ammonia in the liquid ammonia channel 9 is vaporized and mixed with compressed air before being ejected from the atomizing channel 12. In this embodiment, a heating component is provided to realize the self-evaporation of the preheated part of the liquid ammonia, thereby realizing high-efficiency atomization of large-flow liquid ammonia, stabilizing combustion while reducing the consumption of the atomizing medium.

[0038] In one embodiment, see Figure 1The heating component includes a high-voltage electrode 1, a ground electrode 2 and a central wind channel 8. The ground electrode 2 is arranged outside the high-voltage electrode 1, and the outlet of the central wind channel 8 faces the discharge area formed by the high-voltage electrode 1 and the ground electrode 2; the discharge area formed by the high-voltage electrode 1 and the ground electrode 2 is close to the liquid ammonia channel, and a ground electrode hole 3 is arranged on the ground electrode 2 near the liquid ammonia channel. The purpose of setting the ground electrode hole 3 is to allow a small flow of liquid ammonia (ammonia gas) to rotate and diffuse into the sliding arc plasma discharge area. A small amount of air is introduced into the central wind channel.

[0039] This embodiment uses a high-voltage electrode and a ground electrode to achieve continuous plasma discharge, ionize the central wind gas, ignite a small amount of liquid ammonia (ammonia gas) to form a stable small ammonia flame, heat the ground electrode and the metal wall of the atomization channel through which the liquid ammonia flows, and promote the evaporation of part of the liquid ammonia into gas in the atomization channel, which together with the compressed air serves as the atomization medium of the liquid ammonia. On the one hand, it reduces the amount of liquid ammonia that needs to be atomized, and on the other hand, the flow rate of the atomization medium is increased by the self-evaporation of the liquid ammonia, which can reduce the consumption of compressed air.

[0040] The specific working process of this embodiment is as follows: a rotating plasma sliding arc is generated between the high-voltage electrode head 1-1 and the ground electrode 2, ionizing the central wind gas, generating a large number of active free radicals such as O, H, OH, etc., while releasing heat to heat the metal wall of the ground electrode 2. Liquid ammonia is preheated and partially vaporized when passing through the metal wall of the ground electrode 2. A small amount of liquid ammonia (ammonia gas) rotates into the plasma discharge area through the ground electrode hole 3, and is fully mixed with active free radicals such as O, H, OH to produce a combustion chemical reaction. The presence of active free radicals reduces the reaction activation energy, improves the stability of ammonia ignition and combustion, forms a stable ammonia flame, enhances the heat release intensity of the discharge area, and the combustion heat release further increases the temperature of the ground electrode 2 and the inner wall of the atomization channel 12; part of the liquid ammonia absorbs heat and evaporates into ammonia gas in the atomization channel 12, and the liquid ammonia is atomized into fine droplets through medium atomization together with compressed air, and sprayed into the high-temperature furnace for combustion. At the same time, liquid ammonia is atomized to form a spray liquid film. Under the action of negative pressure, the spray liquid film drives the high-temperature flue gas (that is, reflux flue gas) in the furnace to flow back to the discharge area formed by the high-voltage electrode and the ground electrode, further heating the liquid ammonia to vaporize it.

[0041] Preferably, a plurality of ground electrode holes 3 are evenly arranged in the circumferential direction in the middle of the ground electrode 2, and the number of the ground electrode holes 3 is 6 to 8.

[0042] Preferably, the distance between the front edge of the high-voltage electrode head 1 - 1 and the ground electrode 2 is less than 5 mm, so as to generate plasma discharge; wherein the high-voltage electrode head 1 - 1 is preferably umbrella-shaped.

[0043] Preferably, the tail of the central wind channel 8 is connected to the central wind inlet 4, and a cyclone ring 21 is provided at the outlet of the central wind channel 8. The cyclone ring can deflect the central wind flow to form a rotating sliding arc discharge, while cooling the discharge area of ​​the high voltage electrode 1 and the ground electrode 2.

[0044] Preferably, the swirl ring 21 has a plurality of swirl ring holes evenly arranged in the circumference, and the number of the small holes is 4 to 6.

[0045] Preferably, the swirl ring hole has a deflection angle and a swirl number of 0.4 to 0.45.

[0046] Preferably, the ground electrode hole 3 has a deflection angle and a swirl number of 0.3-0.35.

[0047] Preferably, the deflection directions of the cyclone ring hole and the ground electrode hole 3 are opposite.

[0048] Preferably, the high-voltage electrode is a rod-shaped high-voltage electrode; and the ground electrode is a conical ground electrode.

[0049] Preferably, Figure 1 As shown, the plasma-enhanced direct-injection liquid ammonia atomizing nozzle is a concentric sleeve structure, which includes, from the inside to the outside, a central air channel 8, a liquid ammonia channel 9, a compressed air channel 10, and a secondary air channel 11. When the high-voltage electrode is a rod-shaped high-voltage electrode, the rod-shaped high-voltage electrode is located on the inner side of the central air channel.

[0050] More preferably, the front end of the plasma-enhanced direct-injection liquid ammonia atomizing nozzle of this embodiment is, from the inside to the outside, the high-voltage electrode 1, the cyclone ring 21, the ground electrode 2 and the atomizing channel 12, and the secondary air channel 11, and the rear end is, from the inside to the outside, the high-voltage electrode 1, the central air channel 8, the liquid ammonia channel 9 and the compressed air channel 10, and the secondary air channel 11.

[0051] See also Figures 1 to 3 The tail of the central air channel 8 is connected to the central air inlet 4, and a cyclone ring 21 is arranged at the outlet; the inlet end of the liquid ammonia channel 9 is connected to the liquid ammonia inlet 5, and the outlet end is connected to the inlet of the atomizing channel 12; the inlet end of the compressed air channel 10 is connected to the compressed air inlet 6, and the outlet is connected to the inlet of the atomizing channel 12; the tail of the secondary air channel 11 is connected to the secondary air inlet 7, and the outlet is directly connected to the furnace; the outlet of the atomizing channel 12 is directly connected to the furnace.

[0052] Preferably, the central wind channel 8 , the liquid ammonia channel 9 and the compressed air channel 10 are coaxially arranged, and the liquid ammonia channel 9 is located between the central wind channel 8 and the compressed air channel 10 .

[0053] Preferably, see Figure 1The liquid ammonia outer wall of the liquid ammonia channel is composed of a front section 13 of the liquid ammonia outer wall and a rear section 14 of the liquid ammonia outer wall. The front section 13 of the liquid ammonia outer wall is partially sleeved on the outside of the rear section 14 of the liquid ammonia outer wall. The front section 13 of the liquid ammonia outer wall is designed to be angled, and a variable-section channel is formed between the conical surface of the front section 13 of the liquid ammonia outer wall and the conical surface of the conical ground electrode.

[0054] Preferably, see Figure 1 The outer wall of the compressed air passage is composed of a front section 15 of the compressed air outer wall and a rear section 16 of the compressed air outer wall. The front section 15 of the compressed air outer wall is partially sleeved inside the rear section 16 of the compressed air outer wall. The front section 15 of the compressed air outer wall is designed to be angled, and a variable cross-section passage is formed between the conical surface of the front section 15 of the compressed air outer wall and the conical surface of the front section 13 of the liquid ammonia outer wall. The design of the variable cross-section passage can adjust the flow of liquid ammonia and compressed air.

[0055] Preferably, the tail of the front section 13 of the liquid ammonia outer wall is connected to the first push rod screw 17, the tail of the front section 15 of the compressed air outer wall is connected to the second push rod screw 18, the tail of the first push rod screw 17 is connected to the first servo motor 19, and the tail of the second push rod screw 18 is connected to the second servo motor 20. The number of the first push rod screw 17, the second push rod screw 18, the first servo motor 19, and the second servo motor 20 is 2, and they are arranged symmetrically up and down. The first push rod screw 17 is driven by the first servo motor 19 to adjust the position of the front section 13 of the liquid ammonia outer wall and the cross-section of the liquid ammonia channel 9; the second push rod screw 18 is driven by the second servo motor 20 to adjust the position of the front section 15 of the compressed air outer wall and the cross-sectional area of ​​the compressed air channel 10, so as to realize the continuous adjustment of the flow rate of liquid ammonia and compressed air and improve the atomization effect of liquid ammonia; the ratio of the flow rate of compressed air and liquid ammonia can be adjusted to enhance the overall atomization performance of the nozzle and adapt to the internal flow field of the tangential combustion boiler.

[0056] Preferably, the rear section 14 of the liquid ammonia outer wall is supported by the inner cylinder support block 22 on the outer side of the outer wall of the central air channel 8, and the rear section 16 of the compressed air outer wall is supported by the outer cylinder support block 23 on the inner side of the outer wall of the secondary air channel 11. The inner cylinder support block 22 and the cylinder wall, and the outer cylinder support block 23 and the cylinder wall are welded, and the number of the inner cylinder support blocks 22 and the outer cylinder support blocks 23 are both evenly arranged in the circumferential direction.

[0057] Preferably, to ensure the atomization effect, the liquid ammonia pressure is 0.8 MPa ~ 1.0 MPa, and the compressed air pressure is 0.05 ~ 0.1 MPa higher than the liquid ammonia pressure. The ratio of liquid ammonia flow to compressed air flow is between 1:3 ~ 1:5, which is much lower than the conventional medium atomization gas consumption.

[0058] Preferably, in order to ensure the atomization effect and reduce the equipment resistance, the size of the atomization channel 12 is between 3 mm and 5 mm, the atomization expansion angle α is between 0 degrees and 15 degrees, and a direct liquid ammonia film spray jet is formed at the outlet of the atomization channel 12. The hollow film spray structure is conducive to the formation of reflux and entrainment of high-temperature flue gas in the furnace in the central area, thereby enhancing the evaporation intensity of the liquid ammonia on the conical surface of the conical ground electrode 2 and in the atomization channel 12.

[0059] The present invention only needs low-power plasma discharge to maintain a small flame of ammonia gas, the plasma discharge power is 300W-800W, the voltage is 5 kV-10 kV, and a high-frequency DC or AC power supply is used.

[0060] Preferably, according to the plasma discharge power and the size of the rod-shaped high-voltage electrode 1, the half-apex angle β of the conical ground electrode is 30 degrees to 45 degrees, which helps to form a stable sliding arc.

[0061] Correspondingly, the present invention also provides a liquid ammonia burner including the above-mentioned plasma-enhanced direct-injection liquid ammonia atomizing nozzle. Preferably, the central air accounts for 5% to 10% of the total air volume, the compressed air accounts for 60% to 70% of the total air volume, and the secondary air accounts for 20% to 30% of the total air volume; the liquid ammonia combustion NO is controlled by radial air grading. x emission.

[0062] The rod-shaped high-voltage electrode 1 is made of copper material to improve the electrical and thermal conductivity. The rod-shaped high-voltage electrode 1 needs to be insulated in the central wind channel 8. The plasma discharge power used in the present invention is relatively small, which can extend the service life of the electrode. The ground electrode 2, the wall of the liquid ammonia channel 9, and the wall of the atomization channel 12 are made of stainless steel to prevent corrosion caused by ammonia. The walls of the compressed air channel 10 and the secondary air channel 11 are made of ordinary heat-resistant steel.

[0063] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A plasma-enhanced direct-injection liquid ammonia atomizing nozzle, characterized in that: It includes a liquid ammonia channel, a compressed air channel, an atomization channel, a secondary air channel and a heating component; wherein the outlet end of the compressed air channel and the outlet end of the liquid ammonia channel are both connected to the atomization channel; the heating component includes a high-voltage electrode, a ground electrode and a central air channel, the ground electrode is arranged outside the high-voltage electrode, and the outlet of the central air channel faces the discharge area formed by the high-voltage electrode and the ground electrode; the discharge area formed by the high-voltage electrode and the ground electrode is close to the liquid ammonia channel; a ground electrode hole is arranged on the ground electrode near the liquid ammonia channel; The liquid ammonia in the liquid ammonia channel is partially gasified and mixed with the compressed air before being sprayed out from the atomization channel.

2. The plasma-enhanced direct-injection liquid ammonia atomizing nozzle according to claim 1, characterized in that: The distance between the front edge of the head of the high-voltage electrode and the ground electrode is less than 5 mm.

3. The plasma-enhanced direct-injection liquid ammonia atomizing nozzle according to claim 1, characterized in that: A cyclone ring is arranged at the outlet of the central wind channel.

4. The plasma-enhanced direct-injection liquid ammonia atomizing nozzle according to claim 3, characterized in that: The swirl ring is provided with a swirl ring hole.

5. The plasma-enhanced direct-injection liquid ammonia atomizing nozzle according to claim 4, characterized in that: The swirl ring hole has a deflection angle and a swirl number of 0.4 to 0.45; And / or, the ground electrode hole has a deflection angle and a swirl number of 0.3~0.

35.

6. The plasma-enhanced direct-injection liquid ammonia atomizing nozzle according to claim 4, characterized in that: The deflection directions of the cyclone ring hole and the ground electrode hole are opposite.

7. The plasma enhanced direct-injection liquid ammonia atomizing nozzle according to claim 1, characterized in that: The high-voltage electrode is a rod-shaped high-voltage electrode; And / or, the ground electrode is a conical ground electrode.

8. The plasma-enhanced direct-injection liquid ammonia atomizing nozzle according to claim 7, characterized in that: The half apex angle β of the conical ground electrode is 30 degrees to 45 degrees.

9. The plasma-enhanced direct-injection liquid ammonia atomizing nozzle according to claim 1, characterized in that: The central wind channel, the liquid ammonia channel and the compressed air channel are coaxially arranged, and the liquid ammonia channel is located between the central wind channel and the compressed air channel.

10. The plasma-enhanced direct-injection liquid ammonia atomizing nozzle according to claim 1, characterized in that: The liquid ammonia outer wall of the liquid ammonia channel is composed of a front section of the liquid ammonia outer wall and a rear section of the liquid ammonia outer wall. The front section of the liquid ammonia outer wall is partially sleeved on the outside of the rear section of the liquid ammonia outer wall, wherein the front section of the liquid ammonia outer wall is in an angled form, and a variable cross-section channel is formed between the front section of the liquid ammonia outer wall and the ground electrode; And / or, the outer wall of the compressed air channel consists of a front section of the compressed air outer wall and a rear section of the compressed air outer wall, the front section of the compressed air outer wall is partially sleeved inside the rear section of the compressed air outer wall, wherein the front section of the compressed air outer wall is in an angled form, and a variable cross-section channel is formed between the front section of the compressed air outer wall and the front section of the liquid ammonia outer wall.

11. The plasma-enhanced direct-injection liquid ammonia atomizing nozzle according to claim 10, characterized in that: The tail of the front section of the liquid ammonia outer wall is connected to the first push rod screw, and the tail of the first push rod screw is connected to the first servo motor; And / or, the tail of the front section of the compressed air outer wall is connected to the second push rod screw, and the tail of the second push rod screw is connected to the second servo motor.

12. The plasma-enhanced direct-injection liquid ammonia atomizing nozzle according to claim 1, characterized in that: The atomization expansion angle α of the atomization channel is 0 degrees to 15 degrees.

13. The plasma-enhanced direct-injection liquid ammonia atomizing nozzle according to any one of claims 1 to 12, characterized in that: The secondary air channel is coaxially arranged with the liquid ammonia channel.

14. A liquid ammonia burner, characterized in that: A plasma-enhanced direct-injection liquid ammonia atomizing nozzle comprising any one of claims 1 to 13.

15. The liquid ammonia burner according to claim 14, characterized in that: The liquid ammonia pressure in the liquid ammonia burner is 0.8 MPa ~ 1.0 MPa, and the compressed air pressure is 0.05 ~ 0.1 MPa higher than the liquid ammonia pressure.

16. The liquid ammonia burner according to claim 14, characterized in that: The ratio of liquid ammonia flow to compressed air flow is 1:3~1:

5.

17. The liquid ammonia burner according to claim 14, characterized in that: The air volume ratio of central air, compressed air and secondary air is 5~10:60~70:20~30.

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