A high-temperature ammonia combustor based on ammonia catalytic cracking for hydrogen production and ammonia liquid atomization combustion and a running method thereof

Abstract

The application discloses a high-temperature ammonia combustor based on ammonia catalytic cracking hydrogen production and liquid ammonia atomization combustion and an operation method thereof. High-temperature air generated by a grate cooler is introduced into a catalytic cracking device, the heat of the high-temperature air is utilized to promote liquid ammonia gasification, and the catalyst is activated to promote ammonia catalytic cracking to produce hydrogen, thereby forming ammonia, nitrogen and hydrogen mixed gas and improving the reaction activity of fuel. The medium-temperature air generated by the catalytic cracking device and the mixed gas are respectively supplied to first to fifth gas inlets, and stable service flames are formed under the action of sliding arcs, and then the mixed gas introduced into the fourth gas inlet is ignited to form main combustion flames, and the high temperature and active components generated by the main combustion flames promote liquid ammonia atomization and ignite the liquid ammonia to form an axial staged flame. The application fully utilizes ammonia catalytic cracking hydrogen production and high-temperature air, improves flame stability and temperature, can maintain stable combustion of large-flow liquid ammonia, and effectively solves the problems of low flame temperature, ammonia ignition difficulty and unstable combustion.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cement rotary kiln, in particular to a high-temperature ammonia burner based on ammonia catalytic cracking for hydrogen production and liquid ammonia atomization combustion and an operation method thereof, which is used for developing a new type of zero-carbon burner. BACKGROUND

[0002] In order to reduce carbon emissions of fossil energy, it is necessary to vigorously develop green new energy, including photovoltaic, wind power and the like. Due to the strong random fluctuation of wind energy and solar energy, the utilization rate of new energy is low, which causes resource waste. Therefore, energy storage technology is needed to cut peaks and fill valleys. As a kind of energy storage technology, hydrogen energy has advantages of green, high efficiency, no carbon emission and long storage time, and is an important part of future energy system, which helps to accelerate the green and low-carbon transformation of high-energy-consumption and high-carbon-emission industries. However, for large-scale application of hydrogen energy, it is urgent to break through the low-cost and high-efficiency fuel cell technology and the low-cost and safe hydrogen storage and transportation technology. The poor safety and high cost of hydrogen storage and transportation have become the main difficulties in the development of hydrogen energy.

[0003] Ammonia, as a carrier of hydrogen, has the characteristics of high energy density, low storage and transportation cost, and high safety, and is expected to break through the bottleneck of hydrogen energy development. However, there are problems such as low flame propagation speed, difficult ignition, poor flame stability, high NOx emission and the like in the application process of ammonia fuel, which need to be solved urgently. x

[0004] Scholars in the field have carried out in-depth research on the problems of difficult ignition and poor flame stability of ammonia, including technologies such as mixing fossil fuel into ammonia, mixing hydrogen into ammonia, plasma combustion and staged combustion technology. Mixing fossil fuel into ammonia can effectively improve the flame propagation speed of the fuel, but it cannot completely solve the problem of carbon emission; ammonia-hydrogen combustion can improve the flame propagation speed and has no additional carbon emission; Chinese patents with patent application numbers CN202210916289.6 and CN202310260532.8 use ammonia online cracking hydrogen production technology to greatly stabilize ammonia flame, but it is still difficult to achieve stable ammonia combustion at high flow rate; plasma can strengthen combustion through thermal effect, chemical effect and transport effect, which can effectively reduce the ignition delay time and improve the flame propagation speed; Chinese patents with patent application numbers CN202111216787.1, CN202110298162.8 and CN202310426844.1 successfully apply plasma ignition technology to aviation engine aviation kerosene ignition and flame stabilization under extreme conditions, and have achieved outstanding results, but there are few reports on the application of plasma ignition technology in the cement industry. The cement rotary kiln has a high temperature requirement (1800 degrees) for the outlet of the burner, while the temperature of most ammonia burners is about 1100 degrees, so it is urgent to develop a high-temperature ammonia burner for the cement rotary kiln.

[0005] ​In view of the low flame temperature of the ammonia burner, the application provides a high-temperature ammonia burner based on ammonia catalytic cracking hydrogen production and liquid ammonia atomization combustion, which can effectively solve the problems of low ammonia combustion temperature, difficult ammonia ignition under large flow, unstable combustion and the like. SUMMARY

[0006] The application aims to provide a high-temperature ammonia burner based on ammonia catalytic cracking hydrogen production and liquid ammonia atomization combustion, so as to realize reliable ignition and high-temperature combustion of the burner.

[0007] In order to achieve the above-mentioned purpose, the application adopts the technical scheme of:

[0008] A high-temperature ammonia burner based on ammonia catalytic cracking hydrogen production and liquid ammonia atomization combustion, comprising a first gas inlet (1), a second gas inlet (2), a third gas inlet (3), a fourth gas inlet (4), a first cyclone (5), a second cyclone (6), a third cyclone (7), a fourth cyclone (8), a high-voltage electrode (9), a low-voltage electrode (10), a sliding arc (11), a fifth gas inlet (15), a pre-atomization cavity, a sixth gas inlet, a fifth cyclone, a rotary kiln, a first flowmeter, a second flowmeter, a third flowmeter, a fourth flowmeter, a fifth flowmeter, a catalytic cracking device and a grate cooler; the high-voltage electrode is located at the center of the burner and is in air communication with the low-voltage electrode, and the first cyclone is arranged in the air communication channel; the second cyclone, the third cyclone and the fourth cyclone correspond to the air communication channels in which the second gas inlet, the third gas inlet and the fourth gas inlet are located, respectively, and are arranged in the radial direction in sequence; the pre-atomization cavity is located downstream of the burner in the axial direction, the fifth gas inlet and the sixth gas inlet are in communication with the pre-atomization cavity, and the pre-atomization cavity is in communication with the burner cavity through the fifth cyclone; the grate cooler and the catalytic cracking device provide hot air and NH3+N2+H2 mixed gas for the burner.

[0009] Further, the grate cooler heats the normal-temperature air (272 K-350 K) to form high-temperature air (900 K-1300 K), which is then introduced into the catalytic cracking device to heat the liquid ammonia introduced into the catalytic cracking device to form ammonia gas; the catalyst in the catalytic cracking device is activated under the heat of the high-temperature air to promote the cracking of part of the ammonia gas to form NH3+N2+H2 mixed gas; the catalytic cracking device introduces the medium-temperature air (400 K-900 K) into the third flowmeter, the fourth flowmeter and the fifth flowmeter, respectively, and introduces the medium-temperature air into the first gas inlet, the third gas inlet and the fifth gas inlet, respectively; and the NH3+N2+H2 mixed gas produced by the catalytic cracking device is introduced into the first flowmeter and the second flowmeter, respectively, and is introduced into the second gas inlet and the fourth gas inlet, respectively.

[0010] Further, the on-duty flame is formed by the gas burned by the gas from the first air inlet and the second air inlet; the high-voltage electrode and the low-voltage electrode are connected to the high-voltage end and the low-voltage end of the power supply, respectively; the medium-temperature air from the first air inlet forms a rotating flow through the first cyclone, and a sliding arc rotating in the circumferential direction is formed under the action of the airflow; the NH3+N2+H2 mixed gas from the second air inlet forms a rotating flow and a backflow area through the second cyclone; the heat and active components generated by the sliding arc ignite the NH3+N2+H2 mixed gas from the second air inlet, forming the on-duty flame; the on-duty flame is stabilized and the temperature of the on-duty flame is increased through four technical means, i.e., combustion-supporting by the sliding arc, flame stabilization by the rotating backflow area, hydrogen production by ammonia cracking to improve the activity of the fuel, and medium-temperature air to increase the combustion intensity.

[0011] Further, the third air inlet and the fourth air inlet are connected to the medium-temperature air and the NH3+N2+H2 mixed gas, respectively, and the medium-temperature air and the NH3+N2+H2 mixed gas form a rotating flow through the third cyclone and the fourth cyclone, respectively, and then mix downstream to form NH3+N2+H2+O2 mixed gas, which is ignited by the heat and active components of the on-duty flame to form the main combustion flame; the main combustion flame is stabilized and the temperature of the main combustion flame is increased through three technical means, i.e., flame stabilization by the rotating backflow area, hydrogen production by ammonia cracking to improve the activity of the fuel, and medium-temperature air.

[0012] Further, the fifth air inlet is connected to liquid ammonia, and the sixth air inlet is connected to medium-temperature air; the liquid ammonia and the medium-temperature air are mixed in the pre-atomization chamber, part of the liquid ammonia is atomized to generate ammonia gas, and the mixture of the liquid ammonia, the ammonia gas, and the air in the pre-atomization chamber is introduced into the burner chamber through the fifth cyclone, and an axial staged flame is formed under the action of the heat and active components of the main combustion flame; part of the axial staged flame releases heat in the rotary kiln; the axial staged flame is combusted at a high temperature through the heat released by the main combustion flame and the medium-temperature air.

[0013] Further, the operation method of the burner is as follows:

[0014] 1) Start the grate cooler and introduce normal-temperature air; the normal-temperature air passes through the catalytic cracking device and is introduced into the first air inlet, the third air inlet, and the sixth air inlet through the third flow meter, the fourth flow meter, and the fifth flow meter, respectively, and reaches the set flow rate;

[0015] 2) Start the power supply of the sliding arc and reach the set power;

[0016] 3) Start the liquid ammonia supply of the catalytic cracking device and control the liquid ammonia to be introduced into the second air inlet at a small flow rate through the first flow meter;

[0017] 4) After a stable on-duty flame is formed, start the second flow meter to control the liquid ammonia to be introduced into the fourth air inlet at a small flow rate, and form the main combustion flame;

[0018] 5) After the stable main combustion flame is formed, the fifth air inlet is opened, and liquid ammonia is controlled to flow into the burner chamber at a small flow rate to form an axial staged flame;

[0019] 6) After the temperature in the rotary kiln gradually increases, the grate cooler recovers heat to heat the normal temperature air to high temperature air, the catalytic cracking device produces medium temperature air and NH3+N2+H2 mixed gas, and then the stability and temperature of the standby flame and the main combustion flame are improved;

[0020] 7) The first flowmeter is controlled to make the NH3+N2+H2 mixed gas flow into the second air inlet at a large flow rate, and after the standby flame is stable, the second flowmeter is controlled to make the NH3+N2+H2 mixed gas flow into the fourth air inlet at a large flow rate;

[0021] 8) After the main combustion flame is stable, the liquid ammonia is controlled to flow into the burner chamber from the fifth air inlet at a large flow rate to realize full power operation of the burner.

[0022] The beneficial effects of the present application are:

[0023] The present application uses high temperature air generated by the grate cooler to heat the catalyst to promote the cracking of liquid ammonia to produce NH3+N2+H2 mixed gas, and improves the flame propagation speed of the fuel; the medium temperature air and the sliding arc discharge improve the stability and temperature of the standby flame and the main combustion flame, and the mixing of the medium temperature air and the liquid ammonia in the pre-atomization chamber promotes the atomization of the liquid ammonia; the heat generated by the standby flame and the main combustion flame ensures the stable ignition and high temperature combustion of the liquid ammonia in the axial staged flame, and overcomes the problems of difficult ignition of liquid ammonia at high flow rate, unstable combustion and the like. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a schematic diagram of a high temperature ammonia burner for ammonia catalytic cracking hydrogen production and liquid ammonia atomization combustion.

[0025] In the figure: 1-first air inlet; 2-second air inlet; 3-third air inlet; 4-fourth air inlet; 5-first cyclone; 6-second cyclone; 7-third cyclone; 8-fourth cyclone; 9-high voltage electrode; 10-low voltage electrode; 11-sliding arc; 12-standby flame; 13-main combustion flame; 14-axial staged flame; 15-fifth air inlet; 16-pre-atomization chamber; 17-sixth air inlet; 18-fifth cyclone; 19-rotary kiln; 20-first flowmeter; 21-second flowmeter; 22-third flowmeter; 23-fourth flowmeter; 24-fifth flowmeter; 25-catalytic cracking device; 26-grate cooler. DETAILED DESCRIPTION

[0026] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application.

[0027] According to one embodiment of the present application, as shown in Figure 1 Fig. 1, a high-temperature ammonia combustor based on ammonia catalytic cracking for hydrogen production and ammonia mist combustion, comprising a first gas inlet 1, a second gas inlet 2, a third gas inlet 3, a fourth gas inlet 4, a first cyclone 5, a second cyclone 6, a third cyclone 7, a fourth cyclone 8, a high-voltage electrode 9, a low-voltage electrode 10, a sliding arc 11, a fifth gas inlet 15, a pre-mist chamber 16, a sixth gas inlet 17, a fifth cyclone 18, a rotary kiln 19, a first flowmeter 20, a second flowmeter 21, a third flowmeter 22, a fourth flowmeter 23, a fifth flowmeter 24, a catalytic cracking device 25, and a grate cooler 26. The high-voltage electrode 9 is located at the center of the combustor, and maintains an air passage with the low-voltage electrode 10, and the first cyclone 5 is arranged in the air passage. One end of the air passage where the first cyclone 5 is located is provided with the first gas inlet 1. The second cyclone 6 corresponds to the air passage where the second gas inlet 2 is located, the third cyclone 7 corresponds to the air passage where the third gas inlet 3 is located, and the fourth cyclone 8 corresponds to the air passage where the fourth gas inlet 4 is located. The second cyclone 6, the third cyclone 7, and the fourth cyclone 8 are arranged in sequence along the radial direction of the high-temperature ammonia combustor. The pre-mist chamber 16 is located downstream of the combustor along the axial direction. The fifth gas inlet 15 and the sixth gas inlet 17 communicate with the pre-mist chamber 16, and the pre-mist chamber 16 communicates with the combustor chamber through the fifth cyclone 18. The grate cooler 26 and the catalytic cracking device 25 provide hot air and NH3+N2+H2 mixed gas for the combustor. The grate cooler 26 is connected to the catalytic cracking device 25. The air outlet pipeline of the catalytic cracking device 25 is divided into three routes. The first route is sequentially connected to the third flowmeter 22 and the first gas inlet 1. The second route is sequentially connected to the fourth flowmeter 23 and the third gas inlet 3. The third route is sequentially connected to the fifth flowmeter 24 and the sixth gas inlet 17. The hydrogen-containing gas outlet pipeline of the catalytic cracking device 25 is divided into two routes. The first route is sequentially connected to the first flowmeter 20 and the second gas inlet 2. The second route is sequentially connected to the second flowmeter 21 and the fourth gas inlet 4.

[0028] Further, the grate cooler 26 heats the normal temperature air (272 K-350 K) to form high temperature air (greater than 900 K and less than or equal to 1300 K), and then the high temperature air is introduced into the catalytic cracking device 25 to heat the liquid ammonia introduced into the catalytic cracking device 25 to form ammonia gas; the catalytic cracking device 25 is provided with a catalyst, which is activated under the heat of the high temperature air to promote the cracking of part of the ammonia gas to form NH3+N2+H2 mixed gas; the catalytic cracking device 25 introduces the medium temperature air (400 K-900 K) into the third flowmeter 22, the fourth flowmeter 23 and the fifth flowmeter 24 respectively, and then into the first gas inlet 1, the third gas inlet 3 and the sixth gas inlet 17 respectively; the NH3+N2+H2 mixed gas generated by the catalytic cracking device 25 is introduced into the first flowmeter 20 and the second flowmeter 21 respectively, and then into the second gas inlet 2 and the fourth gas inlet 4 respectively.

[0029] Further, the standby flame 12 is formed by the combustion of the gas introduced into the first gas inlet 1 and the second gas inlet 2; the high voltage electrode 9 and the low voltage electrode 10 are connected to the high voltage end and the low voltage end of the power supply respectively, the medium temperature air introduced into the first gas inlet 1 forms a rotational flow through the first cyclone 5, and under the action of the airflow, a sliding arc 11 rotating in the circumferential direction is formed, the NH3+N2+H2 mixed gas introduced into the second gas inlet 2 forms a rotational flow and a backflow area through the second cyclone 6, the heat and active components generated by the sliding arc 11 ignite the NH3+N2+H2 mixed gas introduced into the second gas inlet 2 to form the standby flame 12; the standby flame 12 is stabilized and the temperature of the standby flame 12 is increased by four technical means, i.e., combustion support by the sliding arc, flame stabilization by the rotational flow backflow area, hydrogen production by ammonia cracking to improve fuel activity, and combustion intensity increase by medium temperature air.

[0030] Further, the third gas inlet 3 and the fourth gas inlet 4 introduce medium temperature air and NH3+N2+H2 mixed gas respectively, and the medium temperature air and the NH3+N2+H2 mixed gas form rotational flows through the third cyclone 7 and the fourth cyclone 8 respectively, and then mix downstream to form NH3+N2+H2+O2 mixed gas, which is ignited under the heat and active components of the standby flame 12 to form the main combustion flame 13; the main combustion flame 13 is stabilized and the temperature of the main combustion flame 13 is increased by three technical means, i.e., flame stabilization by the rotational flow backflow area, hydrogen production by ammonia cracking to improve fuel activity, and medium temperature air.

[0031] Further, the fifth gas inlet 15 introduces liquid ammonia, and the sixth gas inlet 17 introduces medium temperature air, the liquid ammonia and the medium temperature air are mixed in the pre-atomization cavity 16, part of the liquid ammonia is atomized to generate ammonia gas, and the mixture of the liquid ammonia, the ammonia gas and the air in the pre-atomization cavity 16 is introduced into the burner chamber through the fifth cyclone 18 to form the axial staged flame 14 under the heat and active components of the main combustion flame; the axial staged flame 14 releases part of the heat in the rotary kiln 19; the axial staged flame 14 realizes high temperature combustion by the heat released by the main combustion flame 13 and the medium temperature air.

[0032] Further, the operation method of the burner is:

[0033] 1) Turn on the grate cooler 26 and input normal temperature air, the normal temperature air passes through the catalytic cracking device 25, and is input into the first air inlet 1, the third air inlet 3 and the sixth air inlet 17 through the third flow meter 22, the fourth flow meter 23 and the fifth flow meter 24 respectively, and reaches the set flow respectively;

[0034] 2) Turn on the power supply of the sliding arc 11 to reach the set power;

[0035] 3) Turn on the liquid ammonia supply of the catalytic cracking device 25, and control the input of the second air inlet 2 through the first flow meter 20 at the maximum flow of 10%;

[0036] 4) After the stable duty flame 12 is formed, turn on the second flow meter 21 to control the input of the ammonia hydrogen nitrogen mixed gas into the fourth air inlet 4 at the maximum flow of 10%, and form the main combustion flame 13;

[0037] 5) After the stable main combustion flame 13 is formed, turn on the fifth air inlet 15 to control the input of the liquid ammonia into the burner chamber at the maximum flow of 10%, and form the axial staged flame 14;

[0038] 6) After the temperature in the rotary kiln gradually increases, the grate cooler 26 recovers the heat to heat the normal temperature air into high temperature air, the catalytic cracking device 25 produces medium temperature air and NH3+N2+H2 mixed gas, and then the stability and temperature of the duty flame 12 and the main combustion flame 13 are improved;

[0039] 7) Control the first flow meter 20 to make the NH3+N2+H2 mixed gas input into the second air inlet 2 at the maximum flow of 100%, and after the duty flame 12 is stable, control the second flow meter 21 to make the NH3+N2+H2 mixed gas input into the fourth air inlet 4 at a large flow;

[0040] 8) After the main combustion flame 13 is stable, control the liquid ammonia to input into the burner chamber from the fifth air inlet 15 at the maximum flow of 100%, and realize the full power operation of the burner.

Claims

1. A high-temperature ammonia burner based on ammonia catalytic cracking for hydrogen production and liquid ammonia atomization combustion, characterized in that: It includes a first air inlet (1), a second air inlet (2), a third air inlet (3), a fourth air inlet (4), a first cyclone separator (5), a second cyclone separator (6), a third cyclone separator (7), a fourth cyclone separator (8), a high-pressure electrode (9), a low-pressure electrode (10), a fifth air inlet (15), a pre-atomization chamber (16), a sixth air inlet (17), a fifth cyclone separator (18), a catalytic cracking device (25), and a grate cooler (26); the high-pressure electrode (9) is located at the center of the burner and maintains an air passage with the low-pressure electrode (10), and the first cyclone separator (5) is installed in the air passage. The first cyclone separator (5) is located at one end of the ventilation channel and is provided with a first air inlet (1); the second cyclone separator (6), the third cyclone separator (7), and the fourth cyclone separator (8) correspond to the ventilation channels where the second air inlet (2), the third air inlet (3), and the fourth air inlet (4) are located, respectively. The second cyclone separator (6), the third cyclone separator (7), and the fourth cyclone separator (8) are arranged in sequence along the radial direction of the high-temperature ammonia burner; the pre-atomization chamber (16) is located downstream of the burner along the axial direction, and the fifth air inlet (15) and the sixth air inlet (17) are connected to the pre-atomization chamber (16). The pre-atomization chamber (16) is connected to the burner chamber through the fifth cyclone separator (18); the grate cooler (26) and the catalytic cracking device (25) provide hot air and NH3+N2+H2 mixture to the burner; The burner also includes a first flow meter (20), a second flow meter (21), a third flow meter (22), a fourth flow meter (23), and a fifth flow meter (24); the grate cooler (26) heats ambient air at 272 K-350 K to form high-temperature air at 900 K-1300 K, and then passes it into the catalytic cracking device (25) to heat the liquid ammonia passing into the catalytic cracking device (25) to form ammonia gas; the catalytic cracking device (25) is equipped with a catalyst, which is activated under the heat of the high-temperature air to promote the cracking of some ammonia gas to form a mixture of NH3+N2+H2 gas; the catalytic cracking device (25) heats the ambient air at 400 K-900 K to form a high-temperature air at 900 K-1300 K, and then passes it into the catalytic cracking device (25) to form a mixture of NH3+N2+H2 gas; the catalytic cracking device (25) heats the ambient air at 400 K-900 K to form a high-temperature air at 900 K-1300 K. The medium-temperature air of K is introduced into the third flow meter (22), the fourth flow meter (23), and the fifth flow meter (24), and into the first air inlet (1), the third air inlet (3), and the sixth air inlet (17), respectively; the NH3+N2+H2 mixed gas generated by the catalytic cracking device (25) is introduced into the first flow meter (20) and the second flow meter (21), and into the second air inlet (2) and the fourth air inlet (4), respectively.

2. The high-temperature ammonia burner based on ammonia catalytic cracking for hydrogen production and liquid ammonia atomization combustion according to claim 1, characterized in that: The burner also includes a sliding arc (11); the standby flame (12) is formed by the combustion of gas introduced through the first air inlet (1) and the second air inlet (2); the high-voltage electrode (9) and the low-voltage electrode (10) are respectively connected to the high-voltage end and the low-voltage end of the power supply. The medium-temperature air introduced through the first air inlet (1) forms a swirling flow through the first swirler (5), and forms a sliding arc (11) rotating in the circumferential direction under the action of the airflow. The NH3+N2+H2 mixture introduced through the second air inlet (2) forms a swirling flow and a recirculation zone through the second swirler (6). The heat and active components generated by the sliding arc (11) ignite the NH3+N2+H2 mixture introduced through the second air inlet (2) to form the standby flame (12); the standby flame (12) stabilizes the flame and increases the flame temperature through four technical means: sliding arc combustion assistance, swirling recirculation zone flame stabilization, ammonia cracking to produce hydrogen to improve fuel activity, and medium-temperature air to improve combustion intensity.

3. A high-temperature ammonia burner based on ammonia catalytic cracking for hydrogen production and liquid ammonia atomization combustion according to claim 2, characterized in that: The third air inlet (3) and the fourth air inlet (4) respectively introduce medium-temperature air and NH3+N2+H2 mixture, which are swirled by the third cyclone separator (7) and the fourth cyclone separator (8) respectively, and mixed downstream to form NH3+N2+H2+O2 mixture. Under the heat and active components of the duty flame (12), it is ignited to form the main combustion flame (13). The main combustion flame (13) stabilizes the flame and increases the flame temperature through three technical means: flame stabilization in the swirling recirculation zone, ammonia cracking to produce hydrogen to improve fuel activity, and medium-temperature air.

4. The high-temperature ammonia burner based on ammonia catalytic cracking for hydrogen production and liquid ammonia atomization combustion according to claim 1, characterized in that: The burner also includes a rotary kiln (19); liquid ammonia is introduced through the fifth air inlet (15), and medium-temperature air is introduced through the sixth air inlet. The liquid ammonia and medium-temperature air are mixed in the pre-atomization chamber (16), and part of the liquid ammonia is atomized to generate ammonia gas. The mixture of liquid ammonia, ammonia gas and air in the pre-atomization chamber (16) is introduced into the burner chamber through the fifth cyclone separator (18), and an axially graded flame (14) is formed under the action of the heat and active components of the main combustion flame. Part of the axially graded flame (14) releases heat in the rotary kiln. The axially graded flame (14) achieves high-temperature combustion through the heat released by the main combustion flame (13) and the medium-temperature air.

5. A high-temperature ammonia burner based on ammonia catalytic cracking for hydrogen production and liquid ammonia atomization combustion according to claim 2, characterized in that: The operation method is as follows: 1) Turn on the grate cooler (26) and introduce ambient air. The ambient air passes through the catalytic cracking device (25) and is introduced into the first air inlet (1), the third air inlet (3), and the sixth air inlet (17) through the third flow meter (22), the fourth flow meter (23), and the fifth flow meter (24), respectively, and reaches the set flow rate. 2) Turn on the power supply of the sliding arc (11) to reach the set power; 3) Start the liquid ammonia supply to the catalytic cracking unit (25) and control it to be introduced into the second air inlet (2) at 5-40% of the maximum design flow rate through the first flow meter (20); 4) After a stable standby flame (12) is formed, turn on the second flow meter (21) and control the ammonia-hydrogen-nitrogen mixture to be introduced into the fourth air inlet (4) at 5-40% of the maximum design flow rate to form the main combustion flame (13); 5) After a stable main combustion flame (13) is formed, the fifth air inlet (15) is opened and liquid ammonia is controlled to be introduced into the burner chamber at a maximum design flow rate of 5-40% to form an axial staged flame (14). 6) After the temperature inside the rotary kiln gradually increases, the grate cooler (26) recovers its heat to heat the ambient air to high temperature air. The catalytic cracking unit (25) produces medium temperature air and NH3+N2+H2 mixture, which in turn improves the stability and temperature of the duty flame (12) and the main combustion flame (13). 7) Control the first flow meter (20) to allow the NH3+N2+H2 mixture to be introduced into the second air inlet (2) at a maximum design flow rate of 40-100%. After the duty flame (12) stabilizes, control the second flow meter (21) to allow the NH3+N2+H2 mixture to be introduced into the fourth air inlet (4) at a maximum design flow rate of 40-100%. 8) After the main combustion flame (13) stabilizes, control the liquid ammonia to be introduced into the burner chamber from the fifth air inlet (15) at a maximum design flow rate of 40-100% to achieve full power operation of the burner.

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