Pure ammonia burner carrying ammonia catalytic combustion and decomposition compounding and control method

Abstract

The invention relates to the technical field of combustion equipment, and discloses a pure ammonia combustor carrying ammonia catalytic combustion and decomposition compositing and a control method.The pure ammonia combustor comprises a combustion sleeve, the combustion sleeve comprises an inner sleeve body and an outer sleeve body, an outer cavity is formed between the inner sleeve body and the outer sleeve body, and the inner sleeve body is provided with an inner cavity; the inner cavity comprises a combustion nozzle, a combustion cavity and a to-be-combusted cavity, a first ignition device is arranged between the combustion cavity and the to-be-combusted cavity, the to-be-combusted cavity communicates with a first air inlet, and the outer cavity comprises a preheating cavity, a combustion catalysis cavity and a catalytic decomposition cavity; the preheating cavity is located on the periphery of the combustion cavity. The combustion catalysis cavity is located on the periphery of the to-be-combusted cavity and provided with an ammonia catalytic combustion catalyst and a second ignition device, and the catalytic decomposition cavity is provided with an ammonia catalytic decomposition catalyst and communicates with the to-be-combusted cavity. The problems that pure ammonia ignition is difficult, the laminar flow combustion speed is low, flames are difficult to stabilize, and NOx emission is high are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of combustion equipment, and particularly relates to a pure ammonia burner equipped with ammonia catalytic combustion decomposition composite and a control method thereof. Background Art

[0002] As a carbon-free clean fuel, ammonia fuel has received extensive attention in recent years. However, there are still some problems in the combustion process of ammonia. Due to the relatively low lower calorific value of ammonia itself, it is prone to insufficient combustion stability and difficult ignition during the combustion process. In addition, since ammonia molecules contain nitrogen, a large amount of fuel-type NOx will be formed during the combustion process. Due to the above disadvantages, it is difficult for ammonia to meet the combustion requirements as a single fuel, thus restricting the development of ammonia energy.

[0003] Hydrogen is complementary to ammonia in terms of ignition and combustion performance, and both are carbon-free fuels without CO2 generation during the combustion process. Therefore, burning the mixture of the two is considered a feasible solution for ammonia energy utilization. Currently, ammonia burners are all mixed with hydrogen for combustion to improve combustion stability. However, the flame temperature of ammonia combustion in current ammonia burners is high, so nozzles made of heat-resistant materials are required, increasing costs. The thermal energy utilization efficiency of ammonia-hydrogen combustion is low, and a large amount of heat is dissipated in the form of radiation through the wall surface, and the sensible heat carried by the flue gas is less, resulting in serious energy waste. In addition, at present, to achieve self-heating hydrogen production and co-combustion with ammonia as a single fuel, a complex process and large-module equipment are required, resulting in additional energy consumption waste and space waste. Summary of the Invention The purpose of the present invention is to provide a pure ammonia burner equipped with ammonia catalytic combustion decomposition composite and a control method thereof, so as to solve one or more technical problems existing in the prior art, and at least provide a beneficial choice or create conditions.

[0004] The technical solutions adopted to solve the above technical problems are as follows: The present invention provides a pure ammonia burner equipped with ammonia catalytic combustion decomposition composite, including: The combustion sleeve includes an inner sleeve and an outer sleeve sleeved on the outer periphery of the inner sleeve. An annular outer chamber is formed between the inner sleeve and the outer sleeve. An inner chamber is provided on the inner periphery of the inner sleeve. The inner chamber includes a combustion nozzle, a combustion chamber, and a chamber to be combusted that are sequentially connected along the axial direction. A first ignition device for igniting the mixed combustion gas is provided between the combustion chamber and the chamber to be combusted. The chamber to be combusted is communicated with a first air inlet for introducing air. The outer chamber includes a preheating chamber, a combustion catalytic chamber, and a catalytic decomposition chamber that are sequentially connected in the direction from the combustion nozzle to the chamber to be combusted. The preheating chamber is located on the outer periphery of the combustion chamber and has a partition heat exchange relationship with the combustion chamber. The combustion catalytic chamber is located on the outer periphery of the chamber to be combusted and has a partition heat exchange relationship with the chamber to be combusted. The combustion catalytic chamber is provided with an ammonia catalytic combustion catalyst for catalytically combusting ammonia and a second ignition device for igniting the mixed gas of ammonia and air. The catalytic decomposition chamber is provided with an ammonia catalytic decomposition catalyst for catalytically decomposing ammonia. The preheating chamber is communicated with a second air inlet for introducing air and an ammonia inlet for introducing ammonia. The catalytic decomposition chamber is communicated with the chamber to be combusted.

[0005] The beneficial effects of the pure ammonia burner of the present invention are as follows: In the start-up stage of the pure ammonia burner, the mixed gas of ammonia and air in a preset ratio is respectively introduced into the preheating chamber through the ammonia inlet and the second air inlet, enters the combustion catalytic chamber through the preheating chamber, and ammonia is ignited by the second ignition device. Under the catalytic action of the ammonia catalytic combustion catalyst, part of the ammonia undergoes a catalytic combustion reaction on the surface of the ammonia catalytic combustion catalyst and generates the heat of catalytic combustion to form a high-temperature mixed gas. Then the high-temperature mixed gas is introduced into the catalytic decomposition chamber. Under the catalytic action of the ammonia catalytic decomposition catalyst and by absorbing and utilizing part of the heat in the high-temperature mixed gas, part of the ammonia in the high-temperature mixed gas undergoes a catalytic decomposition reaction to generate hydrogen, which is mixed in the high-temperature mixed gas to form a mixed gas to be combusted. The mixing of hydrogen in ammonia can effectively improve the combustion characteristics of ammonia. Then the mixed gas to be combusted and the air added from the first air inlet are introduced into the chamber to be combusted together for mixing to form a mixed combustion gas. At this time, the heat generated by the internal catalytic combustion in the combustion catalytic chamber is used to preheat the mixed combustion gas in the chamber to be combusted to make up for the heat consumed by the catalytic decomposition of ammonia and to heat the newly added air. Then the first ignition device is controlled to ignite the mixed combustion gas, and it burns in the combustion chamber to generate a flame.

[0006] During the stable operation stage of the pure ammonia burner, a stable flame is formed in the combustion chamber. At this time, both the second ignition device and the first ignition device can be turned off. Since the preheating chamber and the combustion chamber have a partition heat exchange relationship, when the mixed gas of ammonia and air is in the preheating chamber, it can effectively absorb the heat from the combustion chamber. This can protect the combustion sleeve from overheating while preheating the mixed gas. The temperature of the preheated mixed gas reaches the start-up requirements of catalytic combustion, preheats the ammonia catalytic combustion catalyst, and provides the initial energy for the catalytic combustion reaction, enabling the catalytic combustion reaction to proceed continuously, efficiently, and stably in the combustion catalytic chamber. The formed high-temperature mixed gas then passes through the catalytic decomposition chamber to further form a combustible mixed gas doped with hydrogen. After mixing with the newly introduced air and entering the combustion chamber, a stable ammonia-hydrogen mixed combustion flame can be formed, realizing ammonia-hydrogen mixed combustion under the condition of ammonia as the single fuel.

[0007] The present invention utilizes the self-heating hydrogen production of ammonia catalytic combustion and ammonia catalytic decomposition, and uses heat recycling to preheat the mixed gas in the preheating chamber and the mixed combustion gas in the combustible chamber, ensuring the activation energy of the catalytic combustion catalyst, avoiding the too low temperature of the low-temperature combustible mixed gas after the ammonia catalytic decomposition reaction, which hinders the local flame propagation of ammonia and the generation of excessive residual ammonia, improving the thermal energy utilization efficiency of ammonia-hydrogen combustion, protecting the wall surface of the combustion chamber, so there is no need for heat-resistant materials, reducing the manufacturing cost. Thus, the present invention solves the problems of difficult pure ammonia ignition, slow laminar burning speed, unstable flame, and high NOx emissions.

[0008] As a further improvement of the above technical solution, a circular first air-distributing partition is provided between the preheating chamber and the combustion catalytic chamber, and a plurality of first ventilation holes are distributed on the first air-distributing partition.

[0009] As a further improvement of the above technical solution, a circular second air-distributing partition is provided between the combustion catalytic chamber and the catalytic decomposition chamber, and a plurality of second ventilation holes are distributed on the second air-distributing partition.

[0010] As a further improvement of the above technical solution, a plurality of third ventilation holes are distributed on the outer periphery of the end of the combustible chamber far from the combustion chamber, and the plurality of third ventilation holes are used to connect the catalytic decomposition chamber and the combustible chamber.

[0011] As a further improvement of the above technical solution, the first air inlet is connected to the inner peripheral wall of the combustible chamber, and the first air inlet is arranged along the tangential direction of the inner periphery of the combustible chamber.

[0012] As a further improvement of the above technical solution, a fluid guide body with a conical outer shape is provided between the combustion chamber and the combustible chamber, and the outer diameter of the fluid guide body gradually decreases from the combustion nozzle to the direction of the combustible chamber.

[0013] As a further improvement of the above technical solution, a plurality of swirling fins are circumferentially and spacedly distributed along the outer periphery of the fluid guide body, and a conical funnel-shaped flow guiding toroidal surface is provided on the inner periphery of the combustion chamber near the end close to the combustion chamber to be ignited. The flow guiding toroidal surface is located on the outer periphery of the fluid guide body.

[0014] As a further improvement of the above technical solution, the first ignition device includes a plurality of first ignition power generation parts, and the plurality of first ignition power generation parts are radially and annularly spaced, and are located at one end of the plurality of swirling fins close to the combustion chamber to be ignited. The distance between the first ignition power generation part and the inner wall of the inner cavity is 3-5 mm; The second ignition device includes a second ignition power generation part suspended in the combustion catalytic chamber, and the distance between the second ignition power generation part and the inner wall of the combustion catalytic chamber is 3-5 mm.

[0015] As a further improvement of the above technical solution, the preheating chamber is connected to a gas mixing chamber. One end of the gas mixing chamber in the axial direction is communicated with the ammonia inlet, and the other end is communicated with the preheating chamber. The second air inlet is arranged on the peripheral wall of the gas mixing chamber and is arranged along the tangential direction of the inner periphery of the gas mixing chamber.

[0016] In addition, the present invention also proposes a control method applicable to the pure ammonia burner described above. The control method includes: Controlling to introduce a mixed gas of ammonia and air in a preset ratio into the preheating chamber and then into the combustion catalytic chamber; Controlling the second ignition device to ignite ammonia, and part of the ammonia in the mixed gas undergoes a catalytic combustion reaction to generate a high-temperature mixed gas; Controlling the high-temperature mixed gas to be introduced into the catalytic decomposition chamber, and part of the ammonia in the high-temperature mixed gas undergoes a catalytic decomposition reaction to generate hydrogen, which is mixed in the high-temperature mixed gas to form a combustion-ready mixed gas; Controlling the combustion-ready mixed gas and a preset amount of air to be introduced into the combustion chamber to be ignited for mixing to form a mixed combustion gas, and the mixed combustion gas is preheated by the heat of the combustion catalytic chamber; Controlling the first ignition device to ignite the mixed combustion gas and burn in the combustion chamber; After the pure ammonia burner operates stably, controlling the second ignition device and the first ignition device to stop operating, and preheating the mixed gas in the preheating chamber to a preset catalytic combustion temperature by the heat generated by the combustion in the combustion chamber, so that the mixed gas continuously undergoes a catalytic combustion reaction in the combustion catalytic chamber, and controlling the mixed combustion gas to be introduced into the combustion chamber to continuously burn.

[0017] Other features and advantages of the present invention will be set forth in the following description, and in part will be obvious from the description, or may be learned by practice of the present invention. Description of the Drawings

[0018] The present invention will be further described below in conjunction with the drawings and embodiments; Figure 1 is a pure ammonia burner provided by the present invention, and is a schematic structural diagram of an embodiment thereof; Figure 2 is a pure ammonia burner provided by the present invention, and is a schematic gas flow diagram of an embodiment thereof; Figure 3 is a control method provided by the present invention, and is a flowchart of an embodiment thereof; Reference numerals in the drawings: Combustion sleeve 100; inner sleeve 110; outer sleeve 120; Outer chamber 200; preheating chamber 210; combustion catalytic chamber 220; ammonia catalytic combustion catalyst 221; catalytic decomposition chamber 230; ammonia catalytic decomposition catalyst 231; second air inlet 240; ammonia gas inlet 250; second ignition device 260; second ignition power generation unit 261; gas mixing chamber 270; first gas equalizing partition 280; second gas equalizing partition 290; Inner chamber 300; combustion nozzle 310; combustion chamber 320; chamber to be burned 330; first air inlet 331; third ventilation hole 332; First ignition device 400; first ignition power generation unit 410; Flow guide body 500; swirl fins 510; connecting column 520. Detailed Embodiments

[0019] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0020] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as up, down, etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0021] In the description of the present invention, "a plurality of" means more than two. If the first and second are described only for the purpose of distinguishing technical features, they cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence of the indicated technical features.

[0022] In the description of the present invention, unless otherwise clearly defined, terms such as "arrangement", "installation", and "connection" should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0023] Next, the technical solution of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the following described embodiments are part of the embodiments of the present invention, not all embodiments.

[0024] In the actual production and use of current ammonia burners, the following problems exist: It is difficult to directly burn ammonia as a single fuel. The direct combustion of ammonia will produce a large amount of nitrogen oxides, which need to be solved by adding hydrogen. The flame temperature of ammonia combustion is high, so heat-resistant materials are required, increasing costs. The thermal energy utilization efficiency of ammonia-hydrogen combustion is low. A large amount of heat is dissipated in the form of radiation through the wall surface, and the sensible heat carried by the flue gas is less, resulting in serious energy waste. At present, to achieve self-heating hydrogen production and co-combustion with ammonia as a single fuel, a complex process and large-module equipment are required, resulting in additional energy consumption waste and space waste.

[0025] Therefore, the present invention proposes a pure ammonia burner equipped with ammonia catalytic combustion decomposition composite, which solves the problems of difficult pure ammonia ignition, slow laminar burning speed, unstable flame, and high NOx emissions.

[0026] As Figure 1 shown, the pure ammonia burner of the present invention includes a combustion sleeve 100.

[0027] Among them, the combustion sleeve 100 includes an inner sleeve 110 and an outer sleeve 120 sleeved on the outer periphery of the inner sleeve 110. To improve the smoothness of gas flow and the uniformity of heat reception, both the inner sleeve 110 and the outer sleeve 120 in this embodiment adopt a circular cylinder structure. The two ends of the outer sleeve 120 and the inner sleeve 110 are closed along the axial direction, and an annular outer chamber 200 is formed between the inner sleeve 110 and the outer sleeve 120. The inner periphery of the inner sleeve 110 is provided with an inner chamber 300. The inner chamber 300 includes a combustion nozzle 310, a combustion chamber 320, and a chamber to be burned 330 that are sequentially connected along the axial direction. One end of the inner sleeve 110 in this embodiment is closed, and the combustion nozzle 310 is provided at the other end of the inner sleeve 110, and the waste gas is discharged through the combustion nozzle 310.

[0028] A first ignition device 400 is provided between the combustion chamber 320 and the combustion chamber to be ignited 330. The first ignition device 400 is used to ignite the mixed combustion gas entering the combustion chamber 320 from the combustion chamber to be ignited 330. The combustion chamber to be ignited 330 is communicated with a first air inlet 331 for introducing air. During use, the first air inlet 331 can be connected to an external air supply device.

[0029] The outer chamber 200 of this embodiment includes a preheating chamber 210, a combustion catalytic chamber 220, and a catalytic decomposition chamber 230 that are sequentially communicated in the direction from the combustion nozzle 310 to the combustion chamber to be ignited 330. Among them, the preheating chamber 210 is located on the outer periphery of the combustion chamber 320, and the preheating chamber 210 has a wall heat exchange relationship with the combustion chamber 320. The combustion catalytic chamber 220 is located on the outer periphery of the combustion chamber to be ignited 330, and the combustion catalytic chamber 220 has a wall heat exchange relationship with the combustion chamber to be ignited 330. The preheating chamber 210 is communicated with a second air inlet 240 for introducing air and an ammonia inlet 250 for introducing ammonia. The second air inlet 240 can be connected to an external air supply device, and the ammonia inlet 250 can be connected to an external ammonia supply device. The catalytic decomposition chamber 230 is communicated with the combustion chamber to be ignited 330.

[0030] The combustion catalytic chamber 220 of this embodiment is provided with an ammonia catalytic combustion catalyst 221 and a second ignition device 260. The ammonia catalytic combustion catalyst 221 is used to promote the catalytic combustion of ammonia to generate the heat required for ammonia catalytic decomposition to form a high-temperature mixed gas. The second ignition device 260 is used to ignite the mixed gas of ammonia and air. The second ignition device 260 is started for ignition during the start-up stage or variable operating conditions of the pure ammonia burner. During operation, only a small part of the ammonia in the mixed gas is catalytically burned and ignited in the combustion catalytic chamber 220. Regarding the amount of ammonia catalytic combustion, since ammonia requires air for catalytic combustion, the air volume introduced into the preheating chamber 210 can be controlled.

[0031] The catalytic decomposition chamber 230 of this embodiment is provided with an ammonia catalytic decomposition catalyst 231. The ammonia catalytic decomposition catalyst 231 is used to catalytically decompose ammonia. During operation, only a small part of the ammonia in the high-temperature mixed gas is catalytically decomposed in the catalytic decomposition chamber 230. After the high-temperature mixed gas enters the catalytic decomposition chamber 230 and under the action of the ammonia catalytic decomposition catalyst 231, it absorbs and utilizes the heat of the high-temperature mixed gas to decompose a small part of the ammonia in the high-temperature mixed gas into hydrogen, which is mixed in the high-temperature mixed gas to form a mixed gas to be ignited. The mixing of hydrogen in ammonia can effectively improve the combustion characteristics of ammonia.

[0032] In order to achieve the rapid mixing of ammonia and air, a gas mixing chamber 270 is connected to the preheating chamber 210. One end of the gas mixing chamber 270 in the axial direction communicates with the ammonia inlet 250, and the other end communicates with the preheating chamber 210. The second air inlet 240 is provided on the peripheral wall of the gas mixing chamber 270 and is arranged along the tangential direction of the inner circumference of the gas mixing chamber 270. Air is introduced into the gas mixing chamber 270 tangentially through the second air inlet 240 to generate a swirl, and then mixes with ammonia in the gas mixing chamber 270. The well-mixed gas mixture is then introduced into the preheating chamber 210.

[0033] In the present invention, ammonia is used as the sole fuel source. Ammonia is introduced into the ammonia inlet 250, and air is introduced into the first air inlet 331 and the second air inlet 240 respectively in a certain way. First, a small amount of air is introduced into the second air inlet 240. After mixing with ammonia in the gas mixing chamber 270, it successively enters the preheating chamber 210, the combustion catalytic chamber 220, the catalytic decomposition chamber 230, and the combustion waiting chamber 330. Second, most of the air is introduced into the first air inlet 331, mixes with the combustion waiting mixture in the combustion waiting chamber 330, and then enters the combustion chamber 320 for combustion.

[0034] Among them, an annular first gas equalizing partition 280 is provided between the preheating chamber 210 and the combustion catalytic chamber 220 of this embodiment. The first gas equalizing partition 280 is provided with a plurality of first ventilation holes. The mixed gas introduced from the preheating chamber 210 into the combustion catalytic chamber 220 is shunted through the first gas equalizing partition 280 so that the mixed gas can be evenly introduced into the combustion catalytic chamber 220.

[0035] In addition, an annular second gas equalizing partition 290 is provided between the combustion catalytic chamber 220 and the catalytic decomposition chamber 230. The second gas equalizing partition 290 is provided with a plurality of second ventilation holes. The high-temperature mixed gas introduced from the combustion catalytic chamber 220 into the catalytic decomposition chamber 230 is shunted through the second gas equalizing partition 290 so that the high-temperature mixed gas can be evenly introduced into the catalytic decomposition chamber 230.

[0036] At the same time, the first gas equalizing partition 280 and the second gas equalizing partition 290 can block the ammonia catalytic combustion catalyst 221, and the ammonia catalytic combustion catalyst 221 cannot pass through the above-mentioned second ventilation holes and first ventilation holes.

[0037] A plurality of third ventilation holes 332 are distributed on the outer periphery of the end of the combustion waiting chamber 330 far from the combustion chamber 320. The plurality of third ventilation holes 332 are used to connect the catalytic decomposition chamber 230 and the combustion waiting chamber 330, so that the ammonia catalytic decomposition catalyst 231 cannot pass through the second ventilation holes and the third ventilation holes 332 on the second gas equalizing partition 290, thereby blocking the ammonia catalytic decomposition catalyst 231.

[0038] Further, a deflector 500 with a conical outer shape is provided between the combustion chamber 320 and the combustion chamber to be ignited 330. The outer diameter of the deflector 500 gradually decreases in the direction from the combustion nozzle 310 to the combustion chamber to be ignited 330. The airflow can be diffused and ejected around the outer peripheral wall of the deflector 500 to improve the combustion efficiency.

[0039] To further improve the combustion effect, a plurality of swirl fins 510 are circumferentially and spacedly distributed along the outer periphery of the deflector 500. A conical funnel-shaped flow guiding ring surface is provided on the inner periphery of the end of the combustion chamber 320 close to the combustion chamber to be ignited 330. The flow guiding ring surface is located on the outer periphery of the deflector 500. The combustion airflow can flow along the plurality of swirl fins 510 to form a stable swirl flow field flame. The swirl flow field can form a recirculation zone to form local super-enthalpy combustion, which helps to stabilize the combustion flame.

[0040] One end of the deflector 500 of this embodiment close to the combustion chamber to be ignited 330 is connected with a connecting column 520, and the connecting column 520 is fixedly connected with the closed end of the combustion chamber to be ignited 330, so that the deflector 500 is erected between the combustion chamber 320 and the combustion chamber to be ignited 330.

[0041] The first ignition device 400 of this embodiment includes a plurality of first ignition power generation parts 410. The plurality of first ignition power generation parts 410 are radially and annularly spaced. Each of the plurality of first ignition power generation parts 410 is located at one end of a plurality of swirl fins 510 close to the combustion chamber to be ignited 330. In this embodiment, ignition is carried out through the plurality of first ignition power generation parts 410 to improve the ignition efficiency and make the flame spray more evenly.

[0042] The distance between the first ignition power generation part 410 and the inner wall of the inner cavity 300 is 3-5 mm.

[0043] The second ignition device 260 of this embodiment includes a second ignition power generation part 261 suspended in the combustion catalytic chamber 220. The distance between the second ignition power generation part 261 and the inner wall of the combustion catalytic chamber 220 is 3-5 mm.

[0044] The control methods of the pure ammonia burner of the present invention are different in the start-up stage and the stable operation stage. The start-up speed can be increased in the start-up stage, while the flame stability can be maintained and the energy consumption can be reduced in the stable operation stage.

[0045] In the start-up stage of the pure ammonia burner: Such as Figure 2As shown, ammonia gas and a small amount of air are respectively introduced into the gas mixing chamber 270 through the ammonia inlet 250 and the second air inlet 240 for mixing to obtain a mixed gas. Then the mixed gas is introduced into the preheating chamber 210, enters the combustion catalytic chamber 220 through the preheating chamber 210, and ammonia gas is ignited by the second ignition power generation unit 261. Under the catalytic action of the ammonia catalytic combustion catalyst 221, part of the ammonia gas and air undergo a catalytic combustion reaction on the surface of the ammonia catalytic combustion catalyst 221 to generate the heat of catalytic combustion, so as to form a high-temperature mixed gas. Catalytic combustion has the advantages of reducing the reaction activation energy, low-temperature and high-efficiency combustion, and adapting to complex flow fields and low-concentration reactions; The high-temperature mixed gas is introduced into the catalytic decomposition chamber 230. Under the catalytic action of the ammonia catalytic decomposition catalyst 231 and by absorbing and utilizing the heat in the high-temperature mixed gas, part of the ammonia gas in the high-temperature mixed gas undergoes a catalytic decomposition reaction to generate hydrogen gas, which is mixed in the high-temperature mixed gas to form a mixed gas to be burned. Mixing hydrogen gas in ammonia gas can effectively improve the combustion characteristics of ammonia gas. Specifically, the reaction rate of the active free radical chain reaction is effectively increased, the laminar burning speed increases, the generation of nitrogen oxides is inhibited, and a double breakthrough in combustion rate and environmental protection is achieved; The mixed gas to be burned and the air added from the first air inlet 331 are introduced into the combustion chamber 330 together for mixing to form a mixed combustion gas. At this time, the heat generated by the internal catalytic combustion in the combustion catalytic chamber 220 is used to preheat the mixed combustion gas in the combustion chamber 330 to make up for the heat consumed by the catalytic decomposition of ammonia gas and to heat the newly added air. Then, multiple first ignition power generation units 410 are controlled to ignite the mixed combustion gas to form a stable swirling flow field flame. The swirling flow field can form a recirculation zone and form local super-enthalpy combustion, which helps to stabilize the combustion flame.

[0046] During the stable operation stage of the pure ammonia burner: As Figure 2 shown, the supply of ammonia gas and air is maintained and introduced to form a stable flame in the combustion chamber 320. At this time, both the second ignition device 260 and the first ignition device 400 can be turned off. Since the preheating chamber 210 and the combustion chamber 320 have a relationship of heat exchange through a partition wall, when the mixed gas of ammonia gas and air flows through the preheating chamber 210, it can effectively absorb the heat from the combustion chamber 320. In this way, while protecting the combustion sleeve 100 from overheating, it preheats the mixed gas. The temperature of the preheated mixed gas reaches the start-up requirement of catalytic combustion, preheats the ammonia catalytic combustion catalyst 221, and provides the initial energy for the catalytic combustion reaction, enabling the catalytic combustion reaction to proceed continuously, efficiently and stably in the combustion catalytic chamber 220. The formed high-temperature mixed gas then passes through the catalytic decomposition chamber 230 to further form a mixed gas to be burned doped with hydrogen gas. After mixing with the newly introduced air and being introduced into the combustion chamber 320, a stable ammonia-hydrogen mixed combustion flame can be formed, realizing ammonia-hydrogen mixed combustion under the condition of ammonia gas as the single fuel.

[0047] The present invention utilizes the self-heating hydrogen production from ammonia catalytic combustion and ammonia catalytic decomposition, and uses heat recycling to preheat the mixed gas in the preheating chamber 210 and the mixed combustion gas in the combustion chamber to be burned 330, ensuring the activation performance of the catalytic combustion catalyst, avoiding the excessively low temperature of the low-temperature mixed gas to be burned after the ammonia catalytic decomposition reaction, which hinders the local flame propagation of ammonia and the generation of excessive residual ammonia, improving the thermal energy utilization efficiency of ammonia-hydrogen combustion, protecting the wall surface of the combustion chamber 320, thus eliminating the need for high-temperature-resistant materials, reducing the manufacturing cost, and having a compact structure.

[0048] The pure ammonia burner of the present invention can be used in reforming hydrogen production equipment, on-line ammonia combustion equipment, and industrial furnace equipment. Among them, for reforming hydrogen production equipment: under the condition of zero-carbon industrial hydrogen production, ammonia is used as the sole fuel, and stable combustion and heat source supply of ammonia can be achieved through this pure ammonia burner; for on-line ammonia combustion equipment: under the condition of zero-carbon industry, this pure ammonia burner can overcome the direct combustion of pure ammonia under various conditions, such as on-line hydrogen production equipment, on-line power generation equipment, on-line steam engines, etc.; for industrial furnace equipment: under the condition of zero-carbon industry, this pure ammonia burner can replace the traditional nozzle of the furnace to achieve zero-carbon furnace operation and industrial production.

[0049] As Figure 3 shown, the present invention also proposes a control method applicable to the above-mentioned pure ammonia burner. The control method includes: Step S100: Control the introduction of a mixed gas of ammonia and air in a preset ratio into the preheating chamber 210, and then enter the combustion catalytic chamber 220; Step S200: Control the second ignition device 260 to ignite ammonia, and a part of the ammonia in the mixed gas undergoes a catalytic combustion reaction to generate a high-temperature mixed gas; Step S300: Control the high-temperature mixed gas to enter the catalytic decomposition chamber 230, and a part of the ammonia in the high-temperature mixed gas undergoes a catalytic decomposition reaction to produce hydrogen, which is mixed in the high-temperature mixed gas to form a mixed gas to be burned; Step S400: Control the mixed gas to be burned and a preset amount of air to enter the combustion chamber to be burned 330 for mixing to form a mixed combustion gas, and the mixed combustion gas is preheated by the heat of the combustion catalytic chamber 220; Step S500: Control the first ignition device 400 to ignite the mixed combustion gas and burn it in the combustion chamber 320; Step S600: After the pure ammonia burner operates stably, control the second ignition device 260 and the first ignition device 400 to stop operating, preheat the mixed gas in the preheating chamber 210 to the preset catalytic combustion temperature by the heat generated by the combustion in the combustion chamber 320, so that the mixed gas continuously undergoes a catalytic combustion reaction in the combustion catalytic chamber 220, and control the mixed combustion gas to continuously enter the combustion chamber 320 for combustion.

[0050] During the start-up phase of the pure ammonia burner, the above steps S100 to S500 are executed. During the stable operation phase of the pure ammonia burner, when executing steps S200 and S500, there is no need to start the second ignition device 260 and the first ignition device 400.

[0051] In step S100, ammonia gas is introduced into the ammonia inlet 250, and a small amount of air is introduced into the second air inlet 240 and mixed with the ammonia gas in the gas mixing chamber 270.

[0052] In step S400, most of the air is introduced into the combustion chamber 330 to be burned through the first air inlet 331, and is mixed with the combustion mixture to be burned in the combustion chamber 330 to be burned. The heat inside the combustion catalytic chamber 220 preheats the mixed combustion gas.

[0053] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0054] The embodiments of the present invention have been described in detail above with reference to the drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge scope of those of ordinary skill in the art.

Claims

1. A pure ammonia burner equipped with ammonia catalytic combustion decomposition composite, characterized in that, Comprising: A combustion sleeve, including an inner sleeve and an outer sleeve sleeved on the outer periphery of the inner sleeve. An annular outer chamber is formed between the inner sleeve and the outer sleeve. An inner chamber is provided on the inner periphery of the inner sleeve. The inner chamber includes a combustion nozzle, a combustion chamber, and a chamber to be burned that are sequentially connected along the axial direction. A first ignition device for igniting the mixed combustion gas is provided between the combustion chamber and the chamber to be burned. The chamber to be burned is communicated with a first air inlet for introducing air. The outer chamber includes a preheating chamber, a combustion catalytic chamber, and a catalytic decomposition chamber that are sequentially connected in the direction from the combustion nozzle to the chamber to be burned. The preheating chamber is located on the outer periphery of the combustion chamber and has a partition heat exchange relationship with the combustion chamber. The combustion catalytic chamber is located on the outer periphery of the chamber to be burned and has a partition heat exchange relationship with the chamber to be burned. The combustion catalytic chamber is provided with an ammonia catalytic combustion catalyst for catalytically burning ammonia and a second ignition device for igniting the mixed gas of ammonia and air. The catalytic decomposition chamber is provided with an ammonia catalytic decomposition catalyst for catalytically decomposing ammonia. The preheating chamber is communicated with a second air inlet for introducing air and an ammonia inlet for introducing ammonia. The catalytic decomposition chamber is communicated with the chamber to be burned.

2. The pure ammonia burner according to claim 1, wherein: A circular first air distribution partition is provided between the preheating chamber and the combustion catalytic chamber, and the first air distribution partition is distributed with a plurality of first ventilation holes.

3. The pure ammonia burner according to claim 2, wherein: A circular second air distribution partition is provided between the combustion catalytic chamber and the catalytic decomposition chamber, and the second air distribution partition is distributed with a plurality of second ventilation holes.

4. The pure ammonia burner according to claim 3, wherein: A plurality of third ventilation holes are distributed on the outer periphery of the end of the chamber to be burned far from the combustion chamber, and the plurality of third ventilation holes are used to communicate the catalytic decomposition chamber with the chamber to be burned.

5. The pure ammonia burner according to claim 1, wherein: The first air inlet is connected to the inner peripheral wall of the chamber to be burned, and the first air inlet is arranged along the tangential direction of the inner periphery of the chamber to be burned.

6. The pure ammonia burner according to claim 1, wherein: A deflector with a conical outer shape is provided between the combustion chamber and the chamber to be burned, and the outer diameter of the deflector gradually decreases in the direction from the combustion nozzle to the chamber to be burned.

7. The pure ammonia burner according to claim 6, wherein: A plurality of swirl fins are circumferentially and spacedly distributed on the outer periphery of the deflector. A conical funnel-shaped flow guiding ring surface is provided on the inner periphery of the end of the combustion chamber close to the chamber to be burned, and the flow guiding ring surface is located on the outer periphery of the deflector.

8. The pure ammonia burner according to claim 7, wherein: The first ignition device includes a plurality of first ignition power generation parts, and the plurality of first ignition power generation parts are radially and annularly spaced and are located at one end of the plurality of swirl fins close to the chamber to be burned. The distance between the first ignition power generation part and the inner wall of the inner chamber is 3 - 5 mm; The second ignition device includes a second ignition power generation part suspended in the combustion catalytic chamber, and the distance between the second ignition power generation part and the inner wall of the combustion catalytic chamber is 3-5 mm.

9. The pure ammonia burner according to claim 1, characterized in that: The preheating chamber is connected to a gas mixing chamber. One end of the gas mixing chamber in the axial direction is communicated with the ammonia inlet, and the other end is communicated with the preheating chamber. The second air inlet is arranged on the peripheral wall of the gas mixing chamber and is arranged along the tangential direction of the inner circumference of the gas mixing chamber.

10. A control method, characterized in that, Applicable to the pure ammonia burner according to any one of claims 1 to 9, the control method includes: Controlling to introduce a mixed gas of ammonia and air in a preset ratio into the preheating chamber and then into the combustion catalytic chamber; Controlling the second ignition device to ignite ammonia, and part of the ammonia in the mixed gas undergoes a catalytic combustion reaction to generate a high-temperature mixed gas; Controlling the high-temperature mixed gas to be introduced into the catalytic decomposition chamber, and part of the ammonia in the high-temperature mixed gas undergoes a catalytic decomposition reaction to generate hydrogen, which is mixed in the high-temperature mixed gas to form a mixed gas to be burned; Controlling the mixed gas to be burned and a preset amount of air to be introduced into the combustion chamber to be mixed to form a mixed combustion gas, and the mixed combustion gas is preheated by the heat of the combustion catalytic chamber; Controlling the first ignition device to ignite the mixed combustion gas and burn in the combustion chamber; After the pure ammonia burner operates stably, controlling the second ignition device and the first ignition device to stop operating, preheating the mixed gas in the preheating chamber to a preset catalytic combustion temperature by the heat generated by combustion in the combustion chamber, so that the mixed gas continuously undergoes a catalytic combustion reaction in the combustion catalytic chamber, and controlling the mixed combustion gas to be introduced into the combustion chamber to continuously burn.

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