A pre-combustion stage combustor and ammonia combustor

Abstract

This invention discloses a pre-combustion stage burner and an ammonia burner. The pre-combustion stage burner includes an atomization and pyrolysis section, which comprises a swirling cone, a liquid ammonia nozzle, a first swirler, and a mixing nozzle. The hollow portion of the liquid ammonia nozzle sequentially includes a threaded section, a conical section, a swirling section, a conical surface section, and a nozzle section. The swirling cone is installed in the conical section of the liquid ammonia nozzle and has at least one spiral groove. The first swirler is fitted onto the outside of the nozzle section of the liquid ammonia nozzle. The mixing nozzle is a hollow structure and is located outside the first swirler. The pre-combustion stage burner of this invention enables cold start-up of pure liquid ammonia fuel. In this invention, liquid ammonia is atomized into micron-sized particles by the atomization and pyrolysis section and then fully mixed with the rotating primary air in the mixing nozzle. After high-voltage discharge pyrolysis and ignition, the ignited mixture is ejected through the mixing nozzle and mixed with secondary air in the stabilizing cone. After stabilization by the stabilizing teeth, it is ejected and fully combusted.

Description

Technical Field

[0001] This invention relates to the field of liquid fuel combustion technology, and more particularly to a pre-combustion stage burner and an ammonia burner. Background Technology

[0002] The challenges of hydrogen energy storage and transportation are unlikely to be overcome in the short term. Therefore, ammonia, a hydrogen storage medium that is easy to liquefy, easy to store and transport, and has a higher energy density than hydrogen, has attracted increasing attention from researchers. There is also more and more research on ammonia as a fuel to be co-fired with fossil fuels or even to replace fossil fuel combustion. However, ammonia combustion has the following difficulties: (1) low flame speed and narrow combustible range; (2) high ignition energy and difficulty in cold start; (3) low calorific value and low energy density; (4) high latent heat of vaporization.

[0003] In the research on ammonia blending in coal-fired power plants, replacing coal with ammonia gas of equal calorific value in the boiler requires upgrading the power plant's piping system. Due to ammonia's low calorific value and energy density, the required diameter of the ammonia pipes is relatively large, posing a significant challenge to pipe laying. Furthermore, high-flow-rate ammonia blending necessitates large liquid ammonia evaporators, further complicating and expanding the system. To address these issues, direct liquid ammonia blending was proposed, where liquid ammonia is directly fed into the furnace for combustion. This eliminates the need for a large evaporation system, and laying thinner liquid ammonia pipes is easier. However, due to the high ignition energy and latent heat of vaporization of ammonia, cold start issues arise. To solve these problems, plasma-assisted liquid ammonia combustion was proposed. Liquid ammonia flowing from the ammonia tank bypasses large evaporators for vaporization; instead, it is directly sprayed from the burner, mixed with air, and ignited with plasma assistance.

[0004] CN202510176672.6 discloses a plasma-enhanced direct-fire liquid ammonia atomizing nozzle and a liquid ammonia burner. The plasma enhancement technology used here is to ignite a mixture of liquid ammonia / gaseous ammonia and air using high-voltage discharge. This portion of the liquid ammonia / gaseous ammonia is sprayed out from the swirling hole of the ground electrode. No dedicated liquid ammonia atomizing device is used, resulting in poor liquid ammonia atomization effect, difficulty in ignition, and difficulty in cold start of liquid ammonia.

[0005] Therefore, there is a need to provide a burner with a new liquid ammonia atomization device. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention provides a pre-combustion stage burner, which uses a mechanical atomization device to atomize liquid ammonia into micron-sized particles.

[0007] Accordingly, the present invention also provides an ammonia burner including the above-mentioned pre-combustion stage burner.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A pre-combustion stage burner includes an atomization and pyrolysis section, the atomization and pyrolysis section comprising a swirling cone, a liquid ammonia nozzle, a first swirler, and a mixing nozzle;

[0010] The liquid ammonia nozzle has a hollow structure, and the hollow part of the liquid ammonia nozzle includes, in sequence, a threaded section, a conical section, a swirling section, a conical surface section, and a nozzle section.

[0011] The swirling cone is installed in the conical section of the liquid ammonia nozzle; the swirling cone is provided with at least one spiral groove;

[0012] The first cyclone separator is fitted onto the outside of the nozzle section of the liquid ammonia nozzle;

[0013] The mixing nozzle has a hollow structure and is located on the outside of the first cyclone separator;

[0014] After passing through the swirling cone and the liquid ammonia nozzle, the liquid ammonia forms droplets, which mix with the primary air ejected from the gap between the first swirling cone and the liquid ammonia nozzle in the mixing nozzle.

[0015] The conical section of the liquid ammonia nozzle is cylindrical, the swirling cone is cylindrical in shape, and the spiral groove is disposed on the cylindrical surface of the swirling cone.

[0016] The end of the swirling cone near the threaded section of the liquid ammonia nozzle is a conical surface.

[0017] The swirling cone and the cone section of the liquid ammonia nozzle are in a clearance fit.

[0018] Wherein, the inner diameter of the swirling section of the liquid ammonia nozzle is smaller than the inner diameter of the conical section of the liquid ammonia nozzle, the inner diameter of the nozzle section of the liquid ammonia nozzle is smaller than the inner diameter of the swirling section of the liquid ammonia nozzle, the inner diameter of the bottom surface of the conical section is equal to the inner diameter of the swirling section of the liquid ammonia nozzle, and the inner diameter of the top surface of the conical section is equal to the inner diameter of the nozzle section of the liquid ammonia nozzle.

[0019] The first hydrocyclone has at least one tangential air inlet on its side wall. The cavity formed by the outer conical surface of the liquid ammonia nozzle and the inner conical surface of the first hydrocyclone is a primary air cyclone cavity. The annular channel formed by the outer cylindrical surface of the liquid ammonia nozzle and the inner cylindrical surface of the first hydrocyclone is a primary air nozzle. The primary air enters the primary air cyclone cavity through the tangential air inlet and is then ejected through the primary air nozzle.

[0020] The liquid ammonia nozzle and the first cyclone separator are both located inside the hollow cavity of the mixing nozzle. One end of the mixing nozzle is a threaded end, and the hollow inner wall of the other end of the mixing nozzle is a conical surface.

[0021] The atomization and pyrolysis section further includes a cathode ball, which is disposed on the hollow inner wall of the conical surface of the mixing nozzle.

[0022] The pre-combustion stage burner also includes a high-voltage electrode section, which includes an anode needle. The tip of the anode needle is coaxially disposed within the hollow conical surface of the mixing nozzle, and the distance between the tip of the anode needle and the cathode ball is 1~5mm.

[0023] The high-voltage electrode section also includes a clamping nut, a three-jaw clamp, and a terminal block;

[0024] The anode needle is a solid rod-shaped column. One end of the anode needle is bent into a barb and tapered to a pointed tip. The other end of the anode needle is coaxially fitted with the clamping nut, the three-jaw clamp and the terminal block.

[0025] The three-jaw clamp is a hollow cylinder with one end located inside the clamping nut, and the other end of the three-jaw clamp extends out of the clamping nut and is located inside the anti-rotation joint. The end of the three-jaw clamp located inside the clamping nut has three small grooves circumferentially and the outer edge is chamfered.

[0026] The clamping nut is a hollow cylinder, and one end of the hollow part of the clamping nut is provided with a tapered surface, which abuts against the chamfer of the three-jaw clamp.

[0027] The terminal block is a column. One end of the terminal block has a hole of a certain depth and is fitted onto the anode needle. The other end of the terminal block has a threaded hole for connecting a high-voltage line.

[0028] The high-voltage electrode section also includes an anti-rotation connector, which is a hollow structure with internal threads at both ends of the hollow portion. The clamping nut is threadedly connected to the end of the anti-rotation connector near the mounting flange. The terminal block is threadedly connected to the end of the anti-rotation connector away from the mounting flange, and the terminal block presses against the three-jaw chuck so that the chamfer of the three-jaw chuck is tightly pressed against the conical surface of the clamping nut, thus tightly gripping the anode needle.

[0029] The pre-combustion stage burner also includes a liquid ammonia and a primary air section, which includes a primary air duct, a primary air inlet, a liquid ammonia inlet pipe, an end face sealing plate, and a first flange.

[0030] The liquid ammonia inlet pipe has a hollow straight pipe structure, with a liquid ammonia inlet at one end and a thread at the other end, wherein the hollow part is the liquid ammonia channel;

[0031] The primary air duct is a hollow straight pipe structure, and the primary air duct is coaxially mounted with the liquid ammonia inlet pipe and located outside the liquid ammonia inlet pipe;

[0032] The end of the primary air duct near the liquid ammonia inlet is welded to the liquid ammonia inlet pipe via an end face sealing plate, and the other end of the primary air duct away from the liquid ammonia inlet is provided with threads;

[0033] The first flange is coaxially arranged with the primary air duct and located on the outside of the primary air duct;

[0034] The primary air inlet is located on the side of the primary air duct and between the end face sealing plate and the first flange.

[0035] The pre-combustion stage burner also includes a secondary air section, which includes a secondary air duct, a secondary air inlet, a combustion stabilizing cone, combustion stabilizing teeth, a second flange, and a mounting flange.

[0036] The secondary air duct is a hollow straight pipe structure. A combustion stabilizing cone is coaxially arranged at one end of the secondary air duct, and a second flange is coaxially arranged on the outside of the other end of the secondary air duct.

[0037] The mounting flange is coaxially arranged with the secondary air duct and located on the outside of the secondary air duct;

[0038] The secondary air inlet is located on the side of the secondary air duct and between the second flange and the mounting flange; the first flange of the liquid ammonia and primary air section is connected to the second flange of the secondary air section;

[0039] The combustion stabilizing cone has a hollow straight tube structure, the hollow part of the combustion stabilizing cone is a conical surface, and the end of the combustion stabilizing cone that is adjacent to the secondary air duct is the large diameter;

[0040] The flame-stabilizing teeth are in the shape of bosses and are evenly distributed circumferentially on the inner surface of one end of the small diameter of the flame-stabilizing cone.

[0041] The atomization and pyrolysis section further includes a second cyclone separator. The side of the second cyclone separator is provided with a spiral groove. The second cyclone separator is coaxially mounted between the mixing nozzle and the secondary air duct near the outlet of the mixing nozzle and is axially fixed by a snap ring.

[0042] The number of swirls in the second hydrocyclone is less than the number of swirls in the first hydrocyclone.

[0043] The liquid ammonia pressure in the pre-combustion stage burner is 0.5~2MPa;

[0044] And / or, the theoretical air-fuel ratio for complete combustion of ammonia in the pre-combustion stage burner is 3.57, and the primary air volume accounts for 15% to 30% of the total air volume.

[0045] An ammonia burner comprising the aforementioned pre-combustion stage burner.

[0046] The beneficial effects of this invention are as follows:

[0047] (1) The pre-combustion stage burner of the present invention can realize cold start of pure liquid ammonia fuel. In the present invention, liquid ammonia is partially atomized into micron-sized particles by atomization and cracking, and then fully mixed with the primary air sprayed by rotation in the mixing nozzle. After being cracked by high-voltage discharge and ignited, the ignited mixture is sprayed out through the mixing nozzle and mixed with the secondary air in the combustion stabilizing cone. After being stabilized by the combustion stabilizing teeth, it is sprayed out and fully combusted.

[0048] (2) In this invention, liquid ammonia is atomized by a mechanical atomizing device. The liquid flow impacts the rotating vortex cone, causing the liquid flow to rotate and then spraying out from the liquid ammonia nozzle into the mixing nozzle, forming a fan-shaped droplet spray surface. The primary air is rotated by the first vortex generator and then sprayed into the mixing nozzle, also forming a fan-shaped air surface. The two fan surfaces intertwine and mix thoroughly in the mixing nozzle. On the one hand, this device has a simple structure, good atomization effect, and thorough mixing; on the other hand, compared with medium atomization, the primary air does not need to consider the air ratio corresponding to the atomization effect, but only the air ratio at ignition, which is beneficial for ignition and easy to control.

[0049] (3) This invention employs plasma-assisted ammonia combustion. After mixing on two sides within the mixing nozzle, a high-voltage discharge assembly is installed. The mixed and rotating gas flow is cracked by high-voltage discharge when passing through the high-voltage discharge channel. On the one hand, the cracking generates a large number of active particles and heat, reducing the energy required for ignition and ensuring the stability of ignition. On the other hand, the rotating gas flow can drive the arc to rotate and lengthen along the outer wall of the anode needle, increasing the unbalanced state of the arc, increasing the number of active particles, and further facilitating the ignition of ammonia.

[0050] (4) The present invention adopts an external high-voltage electrode assembly, with the anode needle extending into the mixing nozzle to form a discharge channel with the cathode ball. The anode needle is clamped and positioned by a three-jaw clamp, and the installation position of the anode needle can be adjusted axially and radially to obtain the optimal discharge position. The structure is simple, easy to disassemble and assemble, and convenient to replace. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the overall structure of the pre-combustion stage burner of the present invention.

[0052] Figure 2 This is a schematic cross-sectional view of the overall structure of the pre-combustion stage burner of the present invention.

[0053] Figure 3 This is a schematic diagram of the swirl cone structure of the pre-combustion stage burner of the present invention.

[0054] Figure 4This is a schematic diagram of the structure of the first cyclone in the pre-combustion stage burner of the present invention.

[0055] Figure 5 This is a schematic diagram of the mixing and combustion process of the pre-combustion stage burner of the present invention.

[0056] Figure 6 This is a schematic diagram of the overall structure of the high-voltage electrode of the pre-combustion stage burner of the present invention.

[0057] Figure 7 This is a schematic diagram of the overall structure of the liquid ammonia nozzle of the pre-combustion stage burner of the present invention.

[0058] Figure 8 This is a partial schematic diagram of the primary air and liquid ammonia flow direction in the pre-combustion stage burner of the present invention.

[0059] The attached diagram is labeled as follows: 101-Liquid ammonia inlet pipe, 101a-Liquid ammonia inlet, 102-Primary air duct, 103-Primary air inlet, 104-End face sealing plate, 105-First flange, 2-High voltage electrode section, 201-Anode needle, 202-Three-jaw clamp, 203-Clamping nut, 204-Terminal post, 205-Anti-rotation joint, 206-Insulating sleeve, 207-First insulating nut, 208-Second insulating nut, 209-Sheath nut, 210-Insulating column, 301-Mixing nozzle, 302- Liquid ammonia nozzle, 302a-threaded section, 302b-conical section, 302c-swirling section, 302d-conical surface section, 302e-nozzle section, 302f-chamfered section, 303-swirling cone, 303a-spiral groove, 304-first swirler, 304a-tangential air inlet, 305-second swirler, 306-circlip, 307-cathode ball, 401-secondary air duct, 402-secondary air inlet, 403-flame stabilizing cone, 404-flame stabilizing teeth, 405-second flange, 406-mounting flange. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0061] See Figure 1 and Figure 2A pre-combustion burner includes an atomization and pyrolysis section, a liquid ammonia and primary air section, a high-pressure electrode section 2, and a secondary air section. The liquid ammonia and primary air section is used for the introduction of liquid ammonia and primary air; the atomization and pyrolysis section is used for atomizing liquid ammonia, rotating primary air, and pyrolyzing and igniting the mixture of liquid ammonia droplets and primary air; the secondary air section is used for the introduction and rotation of secondary air; and the high-pressure electrode section 2 is used for clamping and positioning the high-pressure electrode. The liquid ammonia and primary air section, the atomization and pyrolysis section, and the secondary air section are all coaxially arranged, and the liquid ammonia and primary air section and the atomization and pyrolysis section are both located inside the secondary air section.

[0062] See Figure 2 The liquid ammonia and primary air section includes a primary air duct 102, a primary air inlet 103, a liquid ammonia inlet pipe 101, an end face sealing plate 104, and a first flange 105.

[0063] The liquid ammonia inlet pipe 101 is a hollow straight pipe structure. One end of the liquid ammonia inlet pipe 101 is provided with a liquid ammonia inlet 101a, and the other end is provided with threads. The hollow part of the liquid ammonia inlet pipe 101 serves as a liquid ammonia channel. The primary air duct 102 is a hollow straight pipe structure. The primary air duct 102 is coaxially fitted with the liquid ammonia inlet pipe 101 and is located outside the liquid ammonia inlet pipe 101.

[0064] The end of the primary air duct 102 near the liquid ammonia inlet 101a is welded to the liquid ammonia inlet pipe 101 via an end face sealing plate 104. The closed annular space formed by the liquid ammonia inlet pipe 101, the primary air duct 102 and the end face sealing plate 104 is the primary air duct channel. The other end of the primary air duct 102 away from the liquid ammonia inlet 101a is provided with threads.

[0065] The first flange 105 is coaxially arranged with the primary air duct 102 and located on the outside of the primary air duct 102;

[0066] The primary air inlet 103 is disposed on the side of the primary air duct 102 and located between the end face sealing plate 104 and the first flange 105, and the primary air inlet 103 is connected to the primary air duct channel.

[0067] See Figure 2 The atomization and pyrolysis section includes a swirl cone 303, a liquid ammonia nozzle 302, a first swirler 304, and a mixing nozzle 301.

[0068] See Figure 7 The liquid ammonia nozzle 302 has a hollow structure, and the hollow part of the liquid ammonia nozzle 302 includes a threaded section 302a, a conical section 302b, a swirl section 302c, a conical surface section 302d, and a nozzle section 302e in sequence.

[0069] Further, see Figure 2 and Figure 7 The threaded section 302a of the liquid ammonia nozzle 302 is provided with threads and is connected to the threaded end of the liquid ammonia inlet pipe. That is, the liquid ammonia nozzle 302 is installed on the threaded end of the liquid ammonia inlet pipe 101 through the threaded section 302a, and liquid ammonia enters the liquid ammonia nozzle 302 from the liquid ammonia inlet pipe 101.

[0070] See Figure 7 The inner walls of the swirl section 302c, the conical section 302b, and the nozzle section 302e are all cylindrical, but their inner diameters are different. The inner wall of the conical section 302d is an overall conical surface that decreases in size from large to small. Specifically, the inner diameter of the swirl section 302c of the liquid ammonia nozzle 302 is smaller than the inner diameter of the conical section 302b, and the inner diameter of the nozzle section 302e is smaller than the inner diameter of the swirl section 302c. The conical section 302d of the liquid ammonia nozzle 302 connects the swirl section 302c and the nozzle section 302e, meaning that the inner diameter of the bottom surface of the conical section 302d is equal to the inner diameter of the swirl section 302c, and the inner diameter of the top surface of the conical section 302d is equal to the inner diameter of the nozzle section 302e. The chamfered portion 302f serves as a transition between the cylindrical surface of the conical section 302b and the cylindrical surface of the swirl section 302c, and is used for axial positioning of the swirl cone.

[0071] See Figure 2 and Figure 3 The swirling cone 303 is installed in the conical section 302b of the liquid ammonia nozzle 302; the swirling cone 303 is provided with at least one spiral groove 303a. The swirling cone 303 and the conical section 302b of the liquid ammonia nozzle 302 are coaxially arranged, and the swirling cone 303 and the conical section 302b are in a clearance fit.

[0072] See Figure 3 The swirling cone 303 is generally cylindrical, and the spiral groove 303a is disposed on the cylindrical surface of the swirling cone 303. Preferably, the spiral groove 303a of the swirling cone 303 can be a plurality of circumferentially evenly distributed.

[0073] More preferably, one end of the swirling cone 303 near the threaded section 302a of the liquid ammonia nozzle 302 is a conical surface for guiding the liquid ammonia flow.

[0074] During operation, liquid ammonia flows through the spiral groove 303a of the swirl cone 303 to form a rotating liquid flow. The rotating liquid flow continues to rotate in the swirl section 302c, and then accelerates in the cone section 302d. Finally, it is ejected from the nozzle section 302e to form a mist fan.

[0075] See Figure 2The first cyclone separator 304 is fitted onto the outside of the nozzle section 302e of the liquid ammonia nozzle 302. The first cyclone separator 304 is used for primary air rotation. See also Figure 4 The first cyclone separator 304 has at least one tangential air inlet 304a on its sidewall. The cavity formed by the outer conical surface of the liquid ammonia nozzle 302 and the inner conical surface of the first cyclone separator 304 is a primary air cyclone cavity. The annular channel formed by the outer cylindrical surface of the liquid ammonia nozzle 302 and the inner cylindrical surface of the first cyclone separator 304 is a primary air nozzle. Primary air enters the primary air cyclone cavity through the tangential air inlet 304a and is then ejected through the primary air nozzle. Preferably, the tangential air inlets 304a of the first cyclone separator 304 can be a plurality of circumferentially distributed inlets.

[0076] See Figure 2 The mixing nozzle 301 has a hollow structure and is coaxially disposed outside the first cyclone separator 304. The liquid ammonia nozzle 302 and the first cyclone separator 304 are both located inside the hollow interior of the mixing nozzle 301. One end of the mixing nozzle 301 is a threaded end (the threaded end of the mixing nozzle 301 is threaded to the threaded end of the primary air duct 102, simultaneously axially pressing the first cyclone separator 304 and the liquid ammonia nozzle 302). The hollow inner wall of the other end of the mixing nozzle 301 is a conical surface, and the side of the mixing nozzle 301 closest to the primary air nozzle has a smaller diameter. The mixed gas inside the mixing nozzle 301 has an expansion angle when ejected through the inner conical surface, allowing for better mixing with the secondary air after ejection.

[0077] See Figure 8 Liquid ammonia enters the liquid ammonia nozzle 302 after swirling from the swirling cone 303, and then mixes with the primary air ejected from the primary air nozzle (the annular channel formed by the outer cylindrical surface of the liquid ammonia nozzle 302 and the inner cylindrical surface of the first swirler 304).

[0078] See Figure 2 The atomization and pyrolysis section further includes a cathode ball 307, which is disposed on the hollow inner wall of the conical surface of the mixing nozzle 301. The anode needle 201 of the high-voltage electrode section 2 is disposed in the hollow part (hollow conical surface) of the inner wall of the mixing nozzle 301.

[0079] Preferably, the cathode sphere 307 is made of heat-resistant stainless steel.

[0080] See Figure 5In this embodiment, liquid ammonia forms droplets after passing through the swirling cone 303 and the liquid ammonia nozzle 302. These droplets mix with the primary air ejected from the gap between the first swirling device 304 and the liquid ammonia nozzle 302 in the mixing nozzle 301. Specifically, the liquid ammonia flow impacts the swirling cone 303, causing it to rotate and then being ejected from the liquid ammonia nozzle 302 into the mixing nozzle 301, forming a fan-shaped droplet spray surface. The primary air, after being rotated by the first swirling device 304, is also ejected into the mixing nozzle 301, forming a fan-shaped air surface. The two fan-shaped surfaces intertwine and mix thoroughly within the mixing nozzle 301. This device configuration is simple in structure, provides good atomization, and ensures thorough mixing. Furthermore, compared to medium atomization, the primary air does not require consideration of the air ratio corresponding to the atomization effect; only the air ratio during ignition needs to be considered, which is beneficial for ignition and easier to control.

[0081] See Figure 2 The high-pressure electrode section 2 of the pre-combustion stage burner includes an anode needle 201. The tip of the anode needle 201 is coaxially disposed within the hollow conical surface of the mixing nozzle 301. The distance between the tip of the anode needle 201 and the cathode ball 307 is 1-5 mm.

[0082] See Figure 5 The primary air is ejected from the primary air swirl chamber through the primary air nozzle to form a primary fan surface. The primary fan surface and the liquid ammonia atomizing fan surface form a mixing interface, generating a high-voltage discharge between the cathode ball 307 and the anode needle 201. The rotating airflow formed by the mixing interface is broken up by the high-voltage discharge when it passes through the high-voltage discharge channel.

[0083] See Figure 2 and Figure 6 The high-voltage electrode section 2 is connected to the mounting flange 406 via the first insulating nut 207. The high-voltage electrode section 2 includes an anode needle 201, a three-jaw clamp 202, a clamping nut 203, an anti-rotation connector 205, a terminal block 204, an insulating post 210, a first insulating nut 207, and a second insulating nut 208.

[0084] The anode needle 201 is a solid rod-shaped column. One end of the anode needle 201 is bent into a barb and tapered to a pointed tip. The other end of the anode needle 201 is coaxially fitted with the clamping nut 203, the three-jaw clamp 202, and the terminal block 204. The three-jaw clamp 202 is a hollow column with one end located inside the clamping nut 203. The other end of the three-jaw clamp 202 extends out of the clamping nut 203 and is located inside the anti-rotation connector 205. The end of the three-jaw clamp 202 located inside the clamping nut 203 has three small grooves circumferentially and a chamfered outer edge. The clamping nut 203 is a hollow column with a tapered surface at one end of the hollow part. The tapered surface abuts against the chamfer of the three-jaw clamp 202.

[0085] The terminal 204 is a column. One end of the terminal 204 has a hole of a certain depth and is fitted onto the anode needle 201. The other end of the terminal 204 has a threaded hole for connecting a high-voltage line.

[0086] The present invention adopts an external high-voltage electrode assembly. The anode needle 201 extends into the mixing nozzle 301 to form a discharge channel with the cathode ball 307. The anode needle 201 is clamped and positioned by a three-jaw clamp 202. The installation position of the anode needle 201 can be adjusted axially and radially to obtain the optimal discharge position. The structure is simple, easy to disassemble and assemble, and convenient to replace.

[0087] The first insulating nut 207 is hollow, and one end of the first insulating nut 207 is threaded to the outer side of the mounting surface of the mounting flange 406. The hollow part of the first insulating nut 207 is provided with a cut-edge anti-rotation groove. The anti-rotation joint 205 is a hollow structure, and each end of the hollow part (i.e., the anti-rotation joint 205) is provided with an internal thread. The anti-rotation joint 205 is disposed inside the first insulating nut 207 and anti-rotates through the cut edge and the anti-rotation groove of the first insulating nut 207.

[0088] The clamping nut 203 is threadedly connected to the end of the anti-rotation joint 205 near the mounting surface of the mounting flange 406; the terminal 204 is threadedly connected to the end of the anti-rotation joint 205 away from the mounting surface of the mounting flange 406, and the terminal 204 presses the three-jaw clamp 202 so that the chamfer of the three-jaw clamp 202 is pressed tightly against the conical surface of the clamping nut 203, so that the three-jaw clamp 202 tightly holds the anode needle 201.

[0089] The second insulating nut 208 is fitted onto the terminal block 204, and the second insulating nut 208 is connected to the first insulating nut 207 by threads (cylindrical threads). The clamping terminal block 204 also tightly presses the anti-rotation joint 205 and the first insulating nut 207 together. A sheath nut 209 is also connected to the second insulating nut 208 by threads.

[0090] The insulating post 210 is threaded to the outside of the clamping nut 203; an insulating sleeve 206 is also provided between the insulating post 210 and the first insulating nut 207, and the insulating sleeve 206 and the first insulating nut 207 are tightly pressed together by the insulating post 210.

[0091] Preferably, the anode needle 201 is made of tungsten, and the end cone angle is preferably 10-20°.

[0092] Preferably, the first insulating nut 207, the second insulating nut 208, and the insulating sleeve 206 are made of polytetrafluoroethylene or other materials that are resistant to ammonia corrosion and have a sealing effect.

[0093] Preferably, the insulating post 210 is made of ceramic.

[0094] See Figure 2 The pre-combustion stage burner also includes a secondary air section, which includes a secondary air duct 401, a secondary air inlet 402, a combustion stabilizing cone 403, combustion stabilizing teeth 404, a second flange 405, and a mounting flange 406.

[0095] The secondary air duct 401 is a hollow straight pipe structure. A combustion stabilizing cone 403 is coaxially arranged at one end of the secondary air duct 401, and a second flange 405 is coaxially arranged on the outside of the other end of the secondary air duct 401. The first flange 105 and the second flange 405 are connected.

[0096] The mounting flange 406 is coaxially arranged with the secondary air duct 401 and located on the outside of the secondary air duct 401. The high-voltage electrode part 2 is mounted on the mounting flange 406.

[0097] The secondary air inlet 402 is located on the side of the secondary air duct 401 and between the second flange 405 and the mounting flange 406; the first flange 105 of the liquid ammonia and primary air section is connected to the second flange 405 of the secondary air section by bolts.

[0098] The combustion stabilizing cone 403 is a hollow straight pipe structure. The hollow part of the combustion stabilizing cone 403 is a conical surface. One end of the combustion stabilizing cone 403 that is close to the secondary air duct 401 has a large diameter, and the other end has a small diameter.

[0099] The flame-stabilizing teeth 404 are in the shape of bosses and are evenly distributed in a circle on the inner surface of the small-diameter end of the flame-stabilizing cone 403.

[0100] For an even better option, see [link to previous section]. Figure 2 The atomization and pyrolysis section also includes a second cyclone 305 for secondary air rotation. The side of the second cyclone 305 is provided with a spiral groove (not shown in the figure). The second cyclone 305 is coaxially mounted between the mixing nozzle 301 and the secondary air duct 401 near the outlet of the mixing nozzle 301, and is axially fixed by a retaining spring 306.

[0101] More preferably, the swirling cone 303, the first swirler 304 and the second swirler 305 have the same swirling direction, and the second swirler 305 has a smaller number of swirling currents than the first swirler 304.

[0102] More preferably, the expansion angle of the primary air jet cone should not be too large, and should be slightly smaller than the expansion angle of the liquid ammonia atomizing cone.

[0103] More preferably, the liquid ammonia pressure and gas pressure in the pre-combustion stage burner are close, and the liquid ammonia pressure in the pre-combustion stage burner is between 0.5 and 2 MPa;

[0104] Even better, the theoretical air-fuel ratio for complete combustion of ammonia is 3.57, and the primary air volume accounts for 15% to 30% of the total air volume;

[0105] Preferably, gaskets are provided between the first flange 105 and the second flange 405, between the primary air duct 102 and the mixing nozzle 301, and between the liquid ammonia inlet pipe 101 and the liquid ammonia nozzle 302, and the gaskets are made of graphite.

[0106] The pre-combustion stage burner of the present invention can achieve cold start of pure liquid ammonia fuel. In the present invention, liquid ammonia is atomized into micron-sized particles by a mechanical atomizing device and then fully mixed with the rotating primary air in the mixing nozzle 301. After that, it is cracked by high-voltage discharge and ignited. The ignited mixture is sprayed out through the mixing nozzle 301 and mixed with secondary air in the combustion stabilizing cone 403. After being stabilized by the combustion stabilizing teeth 404, it is sprayed out and fully combusted.

[0107] The specific usage process of the pre-combustion stage burner of the present invention is as follows:

[0108] (1) Connect the plasma power supply to the terminal 204 of the high-voltage electrode section 2 via a high-voltage wire;

[0109] (2) The pre-combustion stage burner of the present invention is installed on a large liquid ammonia burner that requires ignition by means of the mounting flange 406;

[0110] (3) Primary air is introduced from the primary air inlet 103. After the primary air is rotated by the first cyclone separator 304, it is sprayed out into the mixing nozzle 301 to form a fan-shaped air surface.

[0111] (4) The plasma power supply is turned on, and the air between the anode needle 201 and the cathode ball 307 in the mixing nozzle 301 is broken down, generating a high-voltage discharge channel;

[0112] (5) Liquid ammonia is introduced from the liquid ammonia inlet 101a. The liquid flow impacts the rotation of the swirling cone 303, causing the liquid flow to rotate. After that, it is sprayed out from the liquid ammonia nozzle 302 into the mixing nozzle 301 and forms a micron-sized fan-shaped liquid droplet spray surface. The liquid ammonia droplet fan surface and the primary air fan surface intertwine in the mixing nozzle 301 and are fully mixed.

[0113] (6) When the mixed and rotating gas flow passes through the high-voltage discharge channel, it is broken down by the high-voltage discharge, generating a large number of active particles and heat. The rotating gas flow drives the electric arc to rotate and elongate along the outer wall of the anode needle, eventually igniting the mixed gas.

[0114] (7) The ignited mixture is sprayed out through the mixing nozzle 301 and mixed with the secondary air in the combustion stabilizing cone 403. After being stabilized by the combustion stabilizing tooth 404, it is sprayed out and fully combusted.

[0115] (8) The fully combusted flame ejected from the pre-combustion stage burner ignites the mixture of liquid ammonia droplets and air ejected from the atomized liquid ammonia burner.

[0116] In this invention, the atomizing mixing and cracking section mechanically atomizes liquid ammonia with a rotating cone and then mixes it uniformly with rotating primary air. The mixture is cracked and ignited in the high-voltage discharge channel formed by the anode needle and cathode ball 307 in the mixing nozzle 301 and then sprayed out. The ignited mixture is mixed with rotating secondary air in the stabilizing cone 403 and then stabilized by the stabilizing teeth 404 before being sprayed out and fully combusted.

[0117] This invention combines mechanical atomization of liquid ammonia with plasma-assisted ammonia combustion, and is supplemented by multi-stage air distribution and a stable combustion structure, enabling cold start-up of pure liquid ammonia fuel. The pre-combustion stage burner of this invention has a simple structure, good atomization effect, and thorough mixing. The high-voltage electrode is external, making it easy to disassemble, install, maintain, and replace, and it has strong engineering practicality.

[0118] Those skilled in the art will readily understand that the above description is merely 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 within the scope of protection of the present invention.

[0119] The parts of this invention not described in detail are well-known in the art. The above embodiments are provided merely for the purpose of describing the invention and are not intended to limit the scope of the invention. The scope of the invention is defined by the appended claims. Various equivalent substitutions and modifications made without departing from the spirit and principles of the invention should be covered within the scope of the invention.

Claims

1. A pre-combustion stage burner, characterized in that, It includes an atomization and pyrolysis section and a high-voltage electrode section. The atomization and pyrolysis section includes a swirling cone, a liquid ammonia nozzle, a first swirler, a mixing nozzle, and a cathode ball. The liquid ammonia nozzle has a hollow structure, and the hollow part of the liquid ammonia nozzle includes, in sequence, a threaded section, a conical section, a swirling section, a conical surface section, and a nozzle section. The swirling cone is installed in the conical section of the liquid ammonia nozzle; the swirling cone is provided with at least one spiral groove; The first cyclone separator is fitted on the outside of the nozzle section of the liquid ammonia nozzle; the annular channel formed by the outer cylindrical surface of the liquid ammonia nozzle and the inner cylindrical surface of the first cyclone separator is a primary air nozzle. The mixing nozzle has a hollow structure and is located on the outside of the first cyclone separator. One end of the mixing nozzle is a threaded end, and the hollow inner wall of the other end of the mixing nozzle is a conical surface. The side of the mixing nozzle closest to the primary air nozzle has a small diameter, and the mixed gas inside the mixing nozzle has an expansion angle when it is ejected through the inner conical surface. The cathode sphere is disposed on the hollow inner wall of the conical surface of the mixing nozzle; The high-voltage electrode section includes an anode needle, the tip of which is coaxially disposed within the hollow conical surface of the mixing nozzle; After passing through the swirling cone and the liquid ammonia nozzle, the liquid ammonia forms droplets, which mix with the primary air ejected from the gap between the first swirling cone and the liquid ammonia nozzle in the mixing nozzle.

2. The pre-combustion stage burner according to claim 1, characterized in that, The conical section of the liquid ammonia nozzle is cylindrical, the swirling cone is cylindrical in shape, and the spiral groove is disposed on the cylindrical surface of the swirling cone.

3. The pre-combustion stage burner according to claim 2, characterized in that, The end of the swirling cone near the threaded section of the liquid ammonia nozzle is a conical surface.

4. The pre-combustion stage burner according to claim 1, characterized in that, The swirling cone and the cone section of the liquid ammonia nozzle are fitted with a clearance.

5. The pre-combustion stage burner according to claim 1, characterized in that, The inner diameter of the swirling section of the liquid ammonia nozzle is smaller than the inner diameter of the conical section of the liquid ammonia nozzle, the inner diameter of the nozzle section of the liquid ammonia nozzle is smaller than the inner diameter of the swirling section of the liquid ammonia nozzle, the inner diameter of the bottom surface of the conical section is equal to the inner diameter of the swirling section of the liquid ammonia nozzle, and the inner diameter of the top surface of the conical section is equal to the inner diameter of the nozzle section of the liquid ammonia nozzle.

6. The pre-combustion stage burner according to claim 1, characterized in that, The first hydrocyclone has at least one tangential air inlet on its side wall. The cavity formed by the outer conical surface of the liquid ammonia nozzle and the inner conical surface of the first hydrocyclone is a primary air cyclone cavity. The primary air enters the primary air cyclone cavity through the tangential air inlet and is then ejected through the primary air nozzle.

7. The pre-combustion stage burner according to claim 1, characterized in that, Both the liquid ammonia nozzle and the first cyclone separator are located inside the hollow interior of the mixing nozzle.

8. The pre-combustion stage burner according to claim 1, characterized in that, The distance between the tip of the anode needle and the cathode ball is 1~5mm.

9. The pre-combustion stage burner according to claim 8, characterized in that, The high-voltage electrode section also includes a clamping nut, a three-jaw clamp, and a terminal block; The anode needle is a solid rod-shaped column. One end of the anode needle is bent into a barb and tapered to a pointed tip. The other end of the anode needle is coaxially fitted with the clamping nut, the three-jaw clamp and the terminal block in sequence. The three-jaw clamp is a hollow cylinder with one end located inside the clamping nut, and the other end of the three-jaw clamp extends out of the clamping nut and is located inside the anti-rotation joint. The end of the three-jaw clamp located inside the clamping nut has three small grooves circumferentially and the outer edge is chamfered. The clamping nut is a hollow cylinder, and one end of the hollow part of the clamping nut is provided with a tapered surface, which abuts against the chamfer of the three-jaw clamp. The terminal block is a column. One end of the terminal block has a hole of a certain depth and is fitted onto the anode needle. The other end of the terminal block has a threaded hole for connecting a high-voltage line.

10. The pre-combustion stage burner according to claim 9, characterized in that, The high-voltage electrode section also includes an anti-rotation connector, which is a hollow structure with internal threads at both ends of the hollow portion. The clamping nut is threadedly connected to the end of the anti-rotation connector near the mounting surface of the mounting flange. The terminal is threadedly connected to the end of the anti-rotation connector away from the mounting surface of the mounting flange, and the terminal presses against the three-jaw chuck so that the chamfer of the three-jaw chuck is tightly pressed against the conical surface of the clamping nut, so that the three-jaw chuck tightly holds the anode needle.

11. The pre-combustion stage burner according to any one of claims 1 to 10, characterized in that, The pre-combustion stage burner also includes a liquid ammonia and a primary air section, which includes a primary air duct, a primary air inlet, a liquid ammonia inlet pipe, an end face sealing plate, and a first flange. The liquid ammonia inlet pipe has a hollow straight pipe structure, with a liquid ammonia inlet at one end and a thread at the other end, wherein the hollow part is the liquid ammonia channel; The primary air duct is a hollow straight pipe structure, and the primary air duct is coaxially mounted with the liquid ammonia inlet pipe and located outside the liquid ammonia inlet pipe; The end of the primary air duct near the liquid ammonia inlet is welded to the liquid ammonia inlet pipe via an end face sealing plate, and the other end of the primary air duct away from the liquid ammonia inlet is provided with threads; The first flange is coaxially arranged with the primary air duct and located on the outside of the primary air duct; The primary air inlet is located on the side of the primary air duct and between the end face sealing plate and the first flange.

12. The pre-combustion stage burner according to claim 11, characterized in that, The pre-combustion stage burner also includes a secondary air section, which includes a secondary air duct, a secondary air inlet, a combustion stabilizing cone, combustion stabilizing teeth, a second flange, and a mounting flange. The secondary air duct is a hollow straight pipe structure. A combustion stabilizing cone is coaxially arranged at one end of the secondary air duct, and a second flange is coaxially arranged on the outside of the other end of the secondary air duct. The mounting flange is coaxially arranged with the secondary air duct and located on the outside of the secondary air duct; The secondary air inlet is located on the side of the secondary air duct and between the second flange and the mounting flange; the first flange of the liquid ammonia and primary air section is connected to the second flange of the secondary air section; The combustion stabilizing cone has a hollow straight tube structure, the hollow part of the combustion stabilizing cone is a conical surface, and the end of the combustion stabilizing cone that is adjacent to the secondary air duct is the large diameter; The flame-stabilizing teeth are in the shape of bosses and are evenly distributed circumferentially on the inner surface of one end of the small diameter of the flame-stabilizing cone.

13. The pre-combustion stage burner according to claim 12, characterized in that, The atomization and pyrolysis section also includes a second cyclone separator. The side of the second cyclone separator is provided with a spiral groove. The second cyclone separator is coaxially mounted between the mixing nozzle and the secondary air duct near the outlet of the mixing nozzle and is axially fixed by a snap ring.

14. The pre-combustion stage burner according to claim 13, characterized in that, The number of swirls in the second hydrocyclone is less than the number of swirls in the first hydrocyclone.

15. The pre-combustion stage burner according to claim 1, characterized in that, The liquid ammonia pressure in the pre-combustion stage burner is 0.5~2MPa; And / or, the theoretical air-fuel ratio for complete combustion of ammonia in the pre-combustion stage burner is 3.57, and the primary air volume accounts for 15% to 30% of the total air volume.

16. An ammonia burner, characterized in that, Includes the pre-combustion stage burner as described in any one of claims 1 to 15.

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