Ammonia burner, combustion system and combustion method

Abstract

This application provides an ammonia burner, a combustion system, and a combustion method. The ammonia burner includes: a primary air duct for providing primary air; a primary ammonia distribution device coupled to the primary air duct and introducing primary ammonia gas into the primary air duct, causing the primary ammonia gas and primary air to mix within the primary air duct to form a premixed gas with an excess air coefficient greater than or equal to 1; an ignition source for igniting the premixed gas; a secondary air duct fitted outside the primary air duct and used to inject secondary air into the flame ejected from the primary air duct; and a secondary ammonia distribution device located radially outside the secondary air duct to inject secondary ammonia gas into the radially inward flame. Based on this, efficient and low-NOx combustion of ammonia fuel can be achieved, promoting the widespread application of ammonia fuel.

Description

Technical Field

[0001] This application relates to the field of low-carbon combustion technology, and in particular to an ammonia burner, combustion system and combustion method. Background Technology

[0002] Ammonia (NH3) is a zero-carbon fuel that does not produce CO2 when burned, which helps reduce CO2 emissions and makes it a good alternative to fossil fuels.

[0003] However, when pure ammonia is used as fuel, it presents challenges in ignition and complete combustion, and it readily produces nitrogen oxides (NOx). x However, issues such as environmental pollution pose challenges in practical applications. Therefore, there are few burners using pure ammonia as fuel in related technologies, hindering the widespread adoption of ammonia fuel. Summary of the Invention

[0004] This application aims to provide an ammonia burner, combustion system, and combustion method to promote the widespread application of ammonia fuel.

[0005] To solve the above-mentioned technical problems, the ammonia burner provided in this application includes:

[0006] A primary ventilation duct is used to provide primary airflow.

[0007] The primary ammonia distribution unit is coupled to the primary air duct and introduces primary ammonia gas into the primary air duct, so that the primary ammonia gas and the primary air mix in the primary air duct to form a premixed gas with an excess air coefficient greater than or equal to 1.

[0008] Ignition source, used to ignite the premixed gas;

[0009] A secondary ventilation duct, fitted outside the primary ventilation duct, is used to inject secondary air into the flames emitted from the primary ventilation duct; and

[0010] The secondary ammonia distribution unit is located on the radially outer side of the secondary air duct to inject secondary ammonia gas into the flame on the radially inner side.

[0011] In some embodiments, the primary ventilation duct includes a primary cylinder and a primary flare, the primary flare being connected to the outlet of the primary cylinder, and the flow area increasing along the outflow direction of the primary air; and / or, the secondary ventilation duct includes a secondary cylinder and a secondary flare, the secondary flare being connected to the outlet of the secondary cylinder, and the flow area increasing along the outflow direction of the secondary air.

[0012] In some embodiments, the primary ventilation duct includes a primary cylinder and a primary flare, and the primary ventilation duct includes a transition section connected between the primary cylinder and the primary flare, and the sidewall of the transition section extends radially along the primary ventilation duct.

[0013] In some embodiments, the ammonia burner includes at least one of the following:

[0014] The primary wind cyclone separator is installed in the primary wind duct and causes the primary wind to swirl and flow within the primary wind duct;

[0015] A secondary cyclone separator is installed in the secondary air duct to facilitate the flow of the secondary cyclone.

[0016] The primary air conditioning element is installed in the air inlet path of the primary air duct and regulates the air volume of the primary air entering the primary air duct.

[0017] The secondary air conditioning element is installed in the air inlet path of the secondary air duct and regulates the air volume of the secondary air entering the secondary air duct;

[0018] An ammonia quantity regulating element is installed on the primary ammonia distribution device and / or the secondary ammonia distribution device, and regulates the amount of ammonia flowing into the primary ammonia distribution device and / or the secondary ammonia distribution device.

[0019] In some embodiments, the ammonia burner is configured as at least one of the following:

[0020] The angle between the swirl blades of the primary and / or secondary cyclones and the axis of the primary duct is 0° to 80°.

[0021] The angle between the swirl blades of the primary and / or secondary cyclones and the axis of the primary duct is adjustable.

[0022] In some embodiments, the primary ammonia distribution device includes a fuel nozzle connected to a primary air duct to introduce primary ammonia gas into the primary air duct; and / or, the secondary ammonia distribution device includes a secondary ammonia distribution pipe and a nozzle, the secondary ammonia distribution pipe being located radially outside the secondary air duct, and the nozzle being connected to the outlet of the secondary ammonia distribution pipe and connected to the secondary ammonia distribution pipe.

[0023] In some embodiments, the primary ammonia distribution device includes an ammonia collection box for connection to an ammonia supply source, and a fuel nozzle is connected to the ammonia collection box; and / or, the ammonia burner includes at least two secondary ammonia distribution devices, which are arranged at circumferential intervals along the secondary air duct, and the nozzles of the at least two secondary ammonia distribution devices face the same or different directions.

[0024] In some embodiments, at least two secondary ammonia distribution devices include at least one of a secondary ammonia distribution device with nozzles oriented parallel to the axial direction of the primary air duct and a secondary ammonia distribution device with nozzles oriented at an angle to the axial direction and / or radial direction of the primary air duct; and / or, at least two secondary ammonia distribution devices include at least one of a secondary ammonia distribution device with nozzles oriented radially inward of the primary air duct and a secondary ammonia distribution device with nozzles oriented radially outward of the primary air duct.

[0025] In some embodiments, the angle between the orientation of the nozzle and the axial direction of the primary air duct is 0° to 90°, and / or the angle between the orientation of the nozzle and the radial direction of the primary air duct is 0° to 180°.

[0026] In some embodiments, the fuel nozzle is configured as at least one of the following:

[0027] The fuel nozzle is located on the side wall of the primary air duct;

[0028] The angle between the jet direction of the fuel nozzle and the axis of the first-stage air duct is 10° to 170°.

[0029] The angle between the jet direction of the fuel nozzle and the radial direction of the first-stage air duct is 0° to 85°.

[0030] In some embodiments, a central air duct is provided in the primary air duct, the central air duct provides central air, and the ignition source extends into the central air duct.

[0031] In some embodiments, a central airflow regulator is provided in the air inlet path of the central air duct, which regulates the airflow volume of the central air entering the central air duct.

[0032] In addition, the combustion system provided in this application includes a boiler and an ammonia burner according to the embodiments of this application.

[0033] Furthermore, based on the ammonia burner of this application embodiment, the combustion method provided by this application includes:

[0034] Primary air is introduced into the primary air duct, and primary ammonia is introduced into the primary ammonia distribution device, so that the primary ammonia and primary air are mixed in the primary air duct to form a premixed gas with an excess air coefficient greater than or equal to 1, and the premixed gas is ignited using an ignition source.

[0035] Secondary air is introduced into the secondary air duct to inject the secondary air into the flame ejected from the primary air duct, so that the primary ammonia ejected from the primary air duct can burn in an oxygen-rich atmosphere.

[0036] Secondary ammonia gas is introduced into the secondary ammonia distribution unit to spray the secondary ammonia gas into the radially inner flame, so that the secondary ammonia gas can be combusted in a reducing atmosphere.

[0037] The ammonia burner provided in this application, based on a relatively simple structure, organizes a certain proportion of staged ammonia fuel and staged air for pre-mixing and staged combustion, achieving rapid ignition, stable combustion, and complete burnout of pure ammonia, while reducing NO. x The emissions of ammonia fuel can be reduced, thus promoting its widespread use.

[0038] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the ammonia burner in an embodiment of this application.

[0041] Figure 2 This is a schematic diagram showing the arrangement of nozzles in different secondary ammonia distribution devices in the embodiments of this application.

[0042] Figure 3 This is a schematic diagram illustrating the working principle of the ammonia burner in the embodiments of this application.

[0043] Explanation of reference numerals in the attached figures:

[0044] 10. Ammonia burner;

[0045] 1. Air distribution system; 11. Primary air duct; 111. Primary duct body; 112. Primary flare; 113. Transition section; 12. Secondary air duct; 121. Secondary duct body; 122. Secondary flare; 14. Central air duct; 141. Central air duct; 142. Central air conditioning component; 15. Air box; 16. Primary air duct; 171. Primary air conditioning component; 172. Secondary air conditioning component; 181. Primary air cyclone separator; 182. Secondary air cyclone separator; 1b. Duct body; 1c. Flare;

[0046] 2. Ammonia Distribution System; 21. Primary Ammonia Distribution Unit; 211. Primary Ammonia Distribution Pipe; 212. Ammonia Collection Box; 213. Fuel Nozzle; 22. Secondary Ammonia Distribution Unit; 221. Secondary Ammonia Distribution Pipe; 222. Nozzle; 223. Nozzle; 224. First Nozzle; 225. Second Nozzle; 226. Third Nozzle; 24. Ammonia Supply Pipe; 241. Ammonia Supply Main Pipe; 242. Ammonia Supply Pipeline; 25. Ammonia Quantity Regulator; 251. Primary Ammonia Regulator; 252. Secondary Ammonia Regulator; 26. Ammonia Supply Regulator;

[0047] 3. Ignition source;

[0048] 41. Oxygen-enriched premixed zone; 42. Partial recirculation burnout zone; 43. Central oxygen-enriched main combustion zone; 44. Staged combustion and nitrogen reduction zone; 45. Flue gas recirculation burnout zone. Detailed Implementation

[0049] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0050] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0051] In the description of this application, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application.

[0052] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0053] Traditional coal-fired power plants emit large amounts of CO2, impacting the global climate. For example, according to statistics, in China, the CO2 emissions from coal-fired power plants account for about 45% of the country's total CO2 emissions. Therefore, reducing CO2 emissions from coal-fired power plants has become a hot topic.

[0054] One of the keys to achieving CO2 emission reduction targets for thermal power generating units is to change the traditional high-carbon emission power generation method that burns fossil fuels and increase the use of low-carbon or zero-carbon fuels.

[0055] Ammonia (NH3), as a zero-carbon fuel, does not produce CO2 when burned compared to traditional fossil fuels. Burning ammonia in thermal power units can significantly reduce CO2 emissions from these units, making it a potential development direction for large-scale CO2 emission reduction in thermal power units.

[0056] However, the combustion of ammonia as fuel in thermal power generating units presents two main problems. Firstly, NH3 has a high ignition temperature, slow flame propagation speed, and a narrow flammability limit, making ignition and burnout relatively difficult. Therefore, NH3 combustion suffers from difficulties in ignition, poor flame stability, and low burnout rate. Secondly, NH3 molecules contain nitrogen atoms, and improper combustion control can easily generate large amounts of the pollutant NO. x (Nitrogen oxides), therefore NO is present. x Pollution problem.

[0057] Due to the aforementioned difficulties, there is currently relatively little research on the application of ammonia fuel, especially the research and application of pure ammonia in boilers.

[0058] In related technologies, there are two main ways to achieve ammonia fuel combustion: one is to directly mix combustible fuels, such as H2, carbon-containing fuels (such as CH4), or pulverized coal into ammonia fuel; the other is to pre-crack ammonia fuel into H2-containing fuel and then mix it with air for combustion.

[0059] While both of these methods can reduce carbon emissions to some extent, they both have certain problems.

[0060] For example, when using the above-mentioned method of combustion by blending hydrogen into ammonia fuel, the combustion device for blending hydrogen needs to be equipped with hydrogen supply equipment. Moreover, due to the high cost, difficulty in storage and transportation of hydrogen, and the unresolved safety issues, this method also needs to consider the economy and safety of hydrogen, resulting in problems such as complex structure, high cost, and poor safety.

[0061] For example, when the above-mentioned method of combustion is adopted by blending carbon-containing combustible fuels (such as methane, propane, liquefied petroleum gas, etc.) into ammonia fuel, it is impossible to truly achieve zero carbon emissions. New equipment is required to treat the CO2 generated during the combustion process, which significantly increases the cost. Therefore, it has problems such as complex structure and high cost.

[0062] For example, when using the above-mentioned method of burning coal powder mixed with ammonia fuel, it is impossible to truly achieve zero carbon emissions. Moreover, the burners on the original coal-fired boilers can only be replaced with low-NOx burners that are mixed with ammonia and coal according to the blending ratio. The retrofitting cost is high and there are restrictions on the type of boiler that can be retrofitted. It cannot achieve a complete replacement of fossil fuels. Therefore, there are problems such as high cost and poor carbon emission reduction effect.

[0063] For example, when using the above method of cracking ammonia into hydrogen-containing fuel in advance and then burning it, a high-temperature (greater than 1000°C) cracking device or catalyst is required, which increases the cost, requires higher safety, and cannot guarantee the specific content and composition of the products generated during the cracking process. It cannot effectively control the stable combustion and burnout of ammonia, making it difficult to apply and promote in the industrial fields of power generation and petrochemicals.

[0064] It is evident that the two ammonia fuel combustion methods of blending or pre-pyrolysis in related technologies cannot effectively solve the problems of difficult ignition, low burnout rate, and NO2 emissions during the combustion of ammonia, especially pure ammonia. x The high emissions, coupled with the high cost and low safety of these two ammonia fuel combustion methods, all hinder the widespread application of ammonia fuel and restrict the further development of low-carbon combustion technology.

[0065] In view of the above, this application provides an ammonia burner, a combustion system, and a combustion method.

[0066] Figures 1-3 The structure and working principle of the ammonia burner of this application are illustrated by way of example.

[0067] See Figures 1-3 The ammonia burner 10 provided in this application includes a primary air duct 11, a primary ammonia distribution device 21, an ignition source 3, a secondary air duct 12, and a secondary ammonia distribution device 22. The primary air duct 11 provides primary air. The primary ammonia distribution device 21 is coupled to the primary air duct 11 and introduces primary ammonia gas into the primary air duct 11, causing the primary ammonia gas and primary air to mix within the primary air duct 11 to form a premixed gas with an excess air coefficient greater than or equal to 1. The ignition source 3 ignites the premixed gas. The secondary air duct 12 is fitted outside the primary air duct 11 and is used to inject secondary air into the flame ejected from the primary air duct 11. The secondary ammonia distribution device 22 is located radially outside the secondary air duct 12 to inject secondary ammonia gas into the radially inward flame.

[0068] Based on the above configuration, the ammonia burner 10 provided in this application can organize a certain proportion of staged ammonia fuel and staged air for pre-mixing and staged combustion, thereby achieving rapid ignition, stable combustion and burnout of pure ammonia, and effectively controlling NO. x The formation of nitrogen oxides (NOx) is reduced, thus decreasing NO production. x Emissions.

[0069] During operation, a certain proportion of ammonia gas (i.e., primary ammonia gas) is introduced into the primary ventilation duct 11, mixing with the primary air in the duct 11 to form a premixed gas with an excess air coefficient greater than or equal to 1. This creates an oxygen-rich, lean-fuel atmosphere. Under this atmosphere, the premixed gas is ignited using an ignition source 3. During the ignition process, since the gas being ignited is a premixed gas formed by the mixture of primary ammonia gas and primary air, rather than pure ammonia gas, ignition is relatively easy, reducing the difficulty of ignition. Furthermore, due to the oxygen-rich, lean-fuel atmosphere, ignition is rapid, and the reaction rate of ammonia fuel is high. The rapid combustion of the premixed gas facilitates the complete combustion of the primary ammonia. Subsequently, the flame formed by the combustion of the premixed gas is ejected from the primary air duct 11 and merges into the secondary air ejected from the secondary air duct 12. This allows the remaining primary ammonia in the flame to further burn in the oxygen-rich, lean-burn atmosphere created by the secondary air, achieving rapid burnout of the primary ammonia and rapid flame propagation. Simultaneously, secondary ammonia is ejected from the secondary ammonia distribution device 22 and merges into the internal flame. The injected secondary ammonia is heated and ignited by the internal flame, allowing it to burn in a lean-burn environment while simultaneously reducing the NO formed by the internal flame. x Reduce NO x emission.

[0070] As can be seen from the above working process, with the cooperation of the primary air duct 11, the secondary air duct 12, the primary ammonia distribution device 21, the secondary ammonia distribution device 22, and the ignition source 3, the ammonia burner 10 can accelerate ignition and improve the burnout rate by creating an oxygen-rich and lean combustion atmosphere in the early stage of combustion. After the flame stabilizes, secondary air is injected into the flame to create an oxygen-rich combustion atmosphere for the remaining primary ammonia, which further promotes the burnout of the primary ammonia. Furthermore, secondary ammonia is introduced into the mixture of secondary air and the remaining primary ammonia to reduce the NO generated in the early stage of combustion. x It also creates a reducing atmosphere for its own combustion, inhibiting NO during its own combustion process. x The generation of [ammonia] enables the ammonia burner 10 to achieve pre-mixing and staged combustion of staged ammonia fuel and staged air, effectively reducing the ignition difficulty of ammonia, improving the ammonia burnout rate, and reducing NO [flammability / degradation]. x The generation and emission of [something].

[0071] Moreover, the aforementioned ammonia burner 10 is a pure ammonia burner, which does not require the mixing of ammonia gas or the pre-decomposition of ammonia gas. Therefore, it has a simpler structure, lower cost, higher safety, and better carbon reduction effect.

[0072] As can be seen, the ammonia burner 10 provided in this application can achieve rapid ignition and complete combustion of pure ammonia gas, as well as NO, based on a relatively simple structure, low cost, and high safety. x The emission reduction effectively solves the difficulties in ignition and complete combustion of pure ammonia and NO. x The high emissions present a challenge that will promote the widespread use of ammonia fuel and facilitate the further development of low-carbon combustion technologies.

[0073] See Figure 1 Both the primary ventilation duct 11 and the secondary ventilation duct 12 can be constructed to include a cylinder 1b and a flared opening 1c, with the flared opening 1c connected to the outlet of the cylinder 1b and the flow area increasing along the outflow direction of the air.

[0074] The flared opening 1c is designed to further improve combustion performance.

[0075] For example, see Figure 1In some embodiments, the primary ventilation duct 11 includes a cylinder 1b and a flared end 1c, referred to as the primary cylinder 111 and the primary flared end 112, respectively. The primary flared end 112 is connected to the outlet of the primary cylinder 111, and its flow area increases along the outflow direction of the primary air. Based on this, the primary flared end 111 (i.e., the flared end 1c of the primary ventilation duct 11) can extend the outflow path of the ignited premixed gas and guide the ignited premixed gas to flow radially outwards towards the secondary air. This can delay the mixing of primary ammonia with the outer secondary ammonia, expand the range of the oxygen-rich combustion atmosphere, promote the complete combustion of primary ammonia, and guide the ignited premixed gas to vortex flow inside and near the downstream area of ​​the primary flared end 112, forming a negative pressure zone. This allows the high-temperature flue gas generated by the combustion of the premixed gas to flow back, heating the unburned premixed gas and rapidly entraining the subsequently introduced secondary air, thereby enhancing the ignition and burnout of the primary ammonia.

[0076] For example, see Figure 1 In some embodiments, the secondary ventilation duct 12 includes a cylinder 1b and a flared opening 1c, referred to as the secondary cylinder 121 and the secondary flared opening 122, respectively. The secondary flared opening 122 is connected to the outlet of the secondary cylinder 121, and its flow area increases along the outflow direction of the secondary air. Based on this, the secondary flared opening 122 (i.e., the flared opening 1c of the secondary ventilation duct 12) can guide the secondary air to flow radially outward, so that the secondary air can envelop as much primary ammonia fuel as possible, providing space and time conditions for the complete reaction of primary ammonia and promoting the burnout of primary ammonia.

[0077] It is evident that setting at least one of the primary air duct 11 and the secondary air duct 12 to have a flared opening 1c is beneficial to the ignition and burnout of the primary ammonia gas, thus effectively improving the combustion effect of the ammonia burner 10.

[0078] Where the primary ventilation duct 11 has a flared opening 1c, see [reference needed]. Figure 1 In some embodiments, a transition section 113 is provided between the cylinder 1b and the flared end 1c of the primary ventilation duct 11. That is, a transition section 113 is provided between the primary cylinder 111 and the primary flared end 112. In other words, the transition section 113 connects the primary cylinder 111 and the primary flared end 112. The sidewall of the transition section 113 extends radially along the primary ventilation duct 11.

[0079] Since the transition section 113 can further extend the outflow path of the ignited premixed gas and guide the ignited premixed gas to flow radially outward towards the secondary ammonia gas, the transition section 113 can further enhance the reflux effect and, together with the primary flare 112, more effectively enhance the ignition and burnout of the primary ammonia gas.

[0080] Additionally, see Figure 1Both the primary air duct 11 and the secondary air duct 12 can be equipped with cyclone separators to promote the mixing of airflows and improve combustion efficiency by making the air swirl.

[0081] For example, see Figure 1 In some embodiments, a primary air cyclone separator 181 is provided inside the primary air duct 11, which causes the primary air to swirl and flow within the primary air duct 11. This increases the turbulence of the primary air, causing it to diffuse and rotate simultaneously within the primary air duct 11, promoting the mixing between the primary air and the primary ammonia gas. This allows for a faster, more thorough, and uniform mixing of the primary air and the primary ammonia gas, thereby promoting the ignition and complete combustion of the primary ammonia gas.

[0082] For example, see Figure 1 In some embodiments, a secondary air cyclone separator 182 is provided inside the secondary air duct 12, which causes the secondary air to swirl. This increases the turbulence of the secondary air, making the secondary air a rotating jet when it is ejected from the secondary air duct 12, promoting the mixing between the secondary air and the ammonia fuel, and promoting the complete combustion of the ammonia fuel.

[0083] Moreover, see Figure 3 The installation of cyclones at various levels helps to form a large flue gas recirculation and burnout zone 45 in front of the ammonia burner 10. The large amount of high-temperature flue gas recirculated is fully mixed with the combustion flame of the staged ammonia gas. The high-temperature flue gas recirculation in the center of the boiler furnace is used to heat and burn the unburned ammonia fuel, and further supplement the air required for the ammonia fuel, so as to achieve complete combustion of all ammonia fuel.

[0084] In some embodiments, the swirling blades of at least one of the primary cyclone separator 181 and the secondary cyclone separator 182 have an angle of 0° to 80° (i.e., greater than or equal to 0° and less than or equal to 80°) with respect to the axial direction of the primary wind tunnel 11, so as to achieve a better swirling effect.

[0085] Furthermore, in some embodiments, the angle between the swirl blades of at least one of the primary swirl vanes 181 and the secondary swirl vanes 182 and the axial direction of the primary air duct 11 is adjustable. This allows for adjustment of the swirl effect according to actual conditions, achieving better combustion performance.

[0086] As an example of the primary ammonia distribution unit 21 in the foregoing embodiments, see Figure 1 The primary ammonia mixing device 21 includes a fuel nozzle 213, which is connected to the primary air duct 11 to introduce primary ammonia gas into the duct 11. In this way, the fuel nozzle 213 can inject primary ammonia gas into the primary air duct 11, mixing it with the primary air. Furthermore, the injection direction of the primary ammonia gas can be easily adjusted by changing the angle of the fuel nozzle 213, achieving a better mixing effect.

[0087] In some embodiments, the angle between the jet direction of the fuel nozzle 213 and the axial direction of the primary air duct 11 is 10° to 170° (i.e., greater than or equal to 10° and less than or equal to 170°), and / or, the angle between the jet direction of the fuel nozzle 213 and the radial direction of the primary air duct 11 is 0° to 85° (i.e., greater than or equal to 0° and less than or equal to 85°). This configuration of the fuel nozzle 213 enhances the mixing efficiency of the primary ammonia and primary air, improving the mixing effect of the primary ammonia and primary air.

[0088] When the primary ammonia mixing unit 21 includes a fuel nozzle 213, see [reference needed]. Figure 1 In some embodiments, the primary ammonia distribution device 21 further includes an ammonia collection box 212, which is connected to an ammonia supply source (not shown in the figure), and a fuel nozzle 213 is connected to the ammonia collection box 212. Based on this, the ammonia gas supplied by the ammonia supply source can first enter the ammonia collection box 212, and then be sprayed into the primary air duct 11 via the fuel nozzle 213. Since the ammonia collection box 212 can store and buffer the ammonia gas, the pressure of the primary ammonia gas is relatively stable, which is beneficial to improving the pressure stability of the primary ammonia gas, thereby improving the combustion effect of the ammonia burner 10.

[0089] Furthermore, as an example of the secondary ammonia distribution device 22 in the aforementioned embodiments, the secondary ammonia distribution device 22 includes a secondary ammonia distribution pipe 221 and a nozzle 222. The secondary ammonia distribution pipe 221 is located radially outside the secondary air duct 12, and the nozzle 222 is connected to the outlet of the secondary ammonia distribution pipe 221 and communicates with it. This facilitates the secondary ammonia distribution device 22 in injecting secondary ammonia gas into the inner flame, utilizing the characteristic of ammonia to reduce NOx, while simultaneously creating a reducing combustion atmosphere with the secondary air, effectively reducing the NOx generated in the main combustion zone. Moreover, it is convenient to achieve better combustion results by adjusting the orientation of the nozzle 222 (which is also the direction of secondary ammonia gas injection).

[0090] For example, see Figure 1 and Figure 2 In some embodiments, the ammonia burner 10 includes at least two secondary ammonia distribution devices 22, which are arranged circumferentially along the secondary air duct 12, and the nozzles 222 of these at least two secondary ammonia distribution devices 22 may face the same or different directions. Providing at least two secondary ammonia distribution devices 22 allows for two-point or multi-point injection of secondary ammonia gas, resulting in better mixing of the secondary ammonia gas. When the nozzles 222 face the same direction, the structure is simple. When the nozzles 222 face different directions, the secondary ammonia gas can be sprayed out in different directions, which is beneficial for achieving better combustion performance.

[0091] The orientation of the nozzle 222 is related to the angle between the nozzle 222 and the ammonia burner 10 in the axial and radial directions, and also to whether the nozzle 222 is facing radially inward or radially outward.

[0092] In some embodiments, the angle between the orientation of the nozzle 222 and the axial direction of the primary air duct 11 is 0° to 90° (i.e., greater than or equal to 0° and less than or equal to 90°), and / or, the angle between the orientation of the nozzle 222 and the radial direction of the primary air duct 11 is 0° to 180° (i.e., greater than or equal to 0° and less than or equal to 180°).

[0093] When the ammonia burner 10 is equipped with secondary ammonia distribution devices 22 with nozzles facing different directions, the at least two secondary ammonia distribution devices 22 include at least one of the following: a secondary ammonia distribution device 22 with nozzles facing parallel to the axial direction of the primary air duct 11 and a secondary ammonia distribution device 22 with nozzles facing at an angle to the axial direction and / or radial direction of the primary air duct 11; and / or, at least one of the following: a secondary ammonia distribution device 22 with nozzles facing the radially inner side of the primary air duct 11 and a secondary ammonia distribution device 22 with nozzles facing the radially outer side of the primary air duct 11.

[0094] In addition, see Figure 1 In some embodiments, a central air duct 14 is provided within the primary air duct 11. The central air duct 14 provides central air. The ignition source 3 extends into the central air duct 14. The central air within the central air duct 14 can provide the combustion air required for the ignition source 3 and can cool the ignition source 3, preventing it from overheating. Moreover, the central air flowing from the central air duct 14 into the primary air duct 11 can provide combustion-supporting air for the combustion of the premixed gas, thereby promoting the ignition or complete combustion of the primary ammonia.

[0095] In the foregoing embodiments, in order to facilitate the control of the oxidation-reduction atmosphere in each combustion zone, an airflow regulator and / or an ammonia regulator can be provided to meet the requirements of different combustion zones by adjusting the ratio of ammonia and airflow at each level.

[0096] For example, see Figure 1 In some embodiments, the ammonia burner 10 includes a primary air regulating component 171, which is disposed in the air inlet path of the primary air duct 11 and regulates the airflow of the primary air entering the primary air duct 11. This facilitates the control of the formation of an oxygen-rich and lean combustion atmosphere within the primary air duct 11.

[0097] For example, see Figure 1In some embodiments, the ammonia burner 10 includes a secondary air regulating component 172, which is disposed in the air inlet path of the secondary air duct 12 and regulates the airflow of the secondary air entering the secondary air duct 12. This facilitates the provision of an appropriate amount of secondary air for further combustion of the primary ammonia and for combustion of subsequently added secondary ammonia, thereby improving the ammonia burnout rate while controlling the generation of nitrogen oxides.

[0098] For example, see Figure 1 In some embodiments, the ammonia burner 10 includes a central airflow regulator 142, which is disposed in the air inlet path of the central air duct 14 and regulates the airflow volume of the central air entering the central air duct 14. This facilitates the provision of an appropriate amount of central airflow to balance ignition, cooling, and the combustion effect of primary ammonia.

[0099] For example, see Figure 1 In some embodiments, the ammonia burner 10 includes an ammonia quantity regulating component 25, which is disposed on the primary ammonia distribution device 21 and / or the secondary ammonia distribution device 22, and regulates the amount of ammonia flowing into the primary and / or secondary ammonia distribution devices 21 and 22. This facilitates control of the ratio of primary and secondary ammonia, meeting the combustion needs of different areas, and achieving both reduced ammonia ignition difficulty and NO reduction. x The goal is to increase the amount of ammonia produced and improve the ammonia burnout rate.

[0100] In addition, an ammonia supply regulator 26 can be installed on the flow path shared by the primary ammonia distribution unit 21 and the secondary ammonia distribution unit 22 and connected to the ammonia supply source to regulate the total amount of ammonia entering the ammonia burner 10.

[0101] The following will provide further details. Figures 1-3 The example shown.

[0102] like Figures 1-3 As shown, in this embodiment, the ammonia burner 10 includes an air distribution system 1, an ammonia distribution system 2, and an ignition source 3.

[0103] Among them, the air distribution system 1 is used to provide primary airflow, secondary airflow, and central airflow. For example... Figure 1As shown, in this embodiment, the air distribution system 1 includes a primary air duct 11, a secondary air duct 12, a wind box 15, a primary air duct 16, a primary air regulating component 171, a secondary air regulating component 172, a central air duct 14, a central air duct 141, and a central air regulating component 142. The primary air duct 11 and the secondary air duct 12 are coaxially fitted from the inside out. The secondary air duct 12 is connected to the wind box 15. The wind box 15 is equipped with a secondary air regulating component 172 to regulate the airflow of the secondary air entering the secondary air duct 12; the primary air duct 11 is connected to the air source (wind box 15 and other air supply devices) through the primary air duct 16, and the primary air regulating component 171 is disposed on the primary air duct 16 to regulate the airflow of the primary air entering the primary air duct 11. Under the action of the primary air regulating component 171 and the secondary air regulating component 172, the ratio of primary air to secondary air and the ratio of two-stage air to two-stage ammonia can be adjusted to meet the requirements of the staged combustion process.

[0104] Specifically, such as Figure 1 As shown, in this embodiment, the primary air duct 11 includes a primary cylinder 111, a transition section 113, and a primary flared end 112 connected sequentially along the axial direction. The secondary air duct 12 includes a secondary cylinder 121 and a secondary flared end 122 connected sequentially along the axial direction. The primary cylinder 111 and the secondary cylinder 121 are coaxially fitted together from the inside to the outside, and their outlets are approximately flush in the axial direction. The primary flared end 112 and the secondary flared end 122 are respectively connected to the outlets of the primary cylinder 111 and the secondary cylinder 121, and both are tapered, gradually widening in the air outlet direction. The angle between the primary flared end 112 and the secondary flared end 122 and the axial direction of the primary air duct 11 is 0° to 90° (i.e., greater than or equal to 0° and less than or equal to 90°). The outlets of the primary flared end 112 and the secondary flared end 122 constitute the outlets of the primary air duct 11 and the secondary air duct 12, respectively. The outlet of the secondary flare 122 is located downstream of the outlet of the primary flare 112, so that the outlets of the primary air duct 11 and the secondary air duct 12 are arranged alternately along the air outlet direction. The transition section 113 connects the primary duct 111 and the primary flare 112 and extends radially along the primary air duct 11.

[0105] The primary flare 112 and the transition section 113 allow the airflow to form a local recirculation burnout zone 42 at the transition section 113. This isolates the central oxygen-rich main combustion zone 43 (the mixed combustion zone of the remaining primary ammonia and secondary air) and the staged combustion denitrification zone 44 (the mixed combustion zone of secondary ammonia and secondary air) within a certain range. On the one hand, this entrains high-temperature flue gas, enhancing the complete combustion and burnout of the primary ammonia. On the other hand, it delays the mixing of the premixed gas with the outer staged ammonia fuel (i.e., secondary ammonia), expanding the range of the oxygen-rich combustion atmosphere and promoting the complete burnout of the primary ammonia.

[0106] The secondary flare 122 causes the secondary air to flow outward, fully mixing with all the ammonia fuel, providing a zone for complete reaction of the ammonia fuel, and promoting complete combustion of the ammonia fuel.

[0107] The primary air cyclone separator 181 and the secondary air cyclone separator 182 are respectively installed inside the primary air duct 111 and the secondary air duct 121 to allow the primary and secondary air to flow in swirling motions. The primary air cyclone separator 181 works in conjunction with the fuel nozzle 213 of the primary ammonia distribution unit 21 to achieve thorough mixing of primary ammonia and primary air, forming a premixed gas. Specifically, the primary air cyclone separator 181 causes the premixed gas formed by the primary air and primary ammonia to form a rotating jet, creating a vortex zone at the outlet of the primary air duct 11, entraining high-temperature flue gas in the furnace, and promoting the ignition and stable combustion of the premixed gas. The secondary air cyclone separator 182 causes the secondary air to rotate, increasing the turbulence of the secondary air and enhancing the mixing of the secondary air with the remaining ammonia in the inner layer and the staged ammonia in the outer layer, promoting complete combustion of all ammonia fuel.

[0108] Both the primary air cyclone separator 181 and the secondary air cyclone separator 182 include multiple swirl blades arranged along the circumference of the ammonia burner 10 (which is also the circumference of the primary air duct 11 and the secondary air duct 12). The angle between these swirl blades and the axial direction of the ammonia burner 10 (which is also the axial direction of the primary air duct 11 and the secondary air duct 12) is 0° to 80° and the angle is adjustable to more flexibly adjust the rotating jet of the primary and secondary air, increase airflow disturbance, and improve combustion effect.

[0109] The system incorporates various secondary air cyclone separators 182 with different blade angles, and coordinates with secondary air regulators 172 on the inlet air path of the secondary air duct 12. This design allows the secondary air to form a rotating jet, increasing airflow turbulence and enhancing the mixing of the secondary air with the primary ammonia combustion flame and secondary ammonia, thus promoting complete combustion of all ammonia fuel. Furthermore, it allows for the formation of different flame patterns, adjusting the optimal oxidation-reduction zone to suit varying ammonia fuel quantities. This achieves complete combustion of ammonia fuel while controlling NO₂ levels. x The generation of .

[0110] Ammonia distribution system 2 is used to provide primary and secondary ammonia gas. For example... Figure 1As shown, in this embodiment, the ammonia distribution system 2 includes a primary ammonia distribution device 21, a secondary ammonia distribution device 22, an ammonia supply pipe 24, an ammonia quantity regulating component 25, and an ammonia supply regulating component 26. The primary ammonia distribution device 21 includes a primary ammonia distribution pipe 211, an ammonia collection box 212, and a fuel nozzle 213. The secondary ammonia distribution device 22 includes a secondary ammonia distribution pipe 221 and a nozzle 222. The fuel nozzle 213 is disposed on the side wall of the primary air duct 11 and located within the ammonia collection box 212, which is connected to the ammonia supply source via the primary ammonia distribution pipe 211 and the ammonia supply pipe 24. It communicates with the interior of the primary air duct 11 to inject primary ammonia gas into the primary air duct 11. The secondary ammonia distribution pipe 221 is arranged radially outward of the secondary air duct 12. Both the primary and secondary ammonia distribution pipes 211 and 221 are connected to the ammonia supply pipe 24, which is connected to the ammonia supply source, allowing the ammonia gas supplied by the ammonia supply source to be divided into two streams, flowing into the primary ammonia distribution device 21 and the secondary ammonia distribution device 22, respectively. Both the primary ammonia distribution pipe 211 and the secondary ammonia distribution pipe 221 are equipped with ammonia quantity regulating components 25, namely primary ammonia regulating component 251 and secondary ammonia regulating component 252, respectively. The ammonia supply pipe 24 is equipped with an ammonia supply regulating component 26 to control the total amount of ammonia entering the ammonia burner 10 and the ratio of primary to secondary ammonia to meet combustion requirements. Furthermore, the primary ammonia regulating component 251 and the secondary ammonia regulating component 252 can also cooperate with the primary air regulating component 171 and the secondary air regulating component 172 to adjust the mixing ratio of primary ammonia to primary air, and the ratio of secondary air to both primary and secondary ammonia, forming the required oxygen-rich and lean combustion atmosphere, the central oxygen-rich combustion atmosphere, and the outer reducing combustion atmosphere. This facilitates ignition while reducing NO₂ levels. x Increase the amount of ammonia produced, thereby improving the burnout rate of pure ammonia.

[0111] Specifically, such as Figure 1 As shown, in this embodiment, the ammonia supply pipe 24 includes an ammonia supply main pipe 241 and an ammonia supply pipeline 242. The ammonia supply main pipe 241 is connected to the ammonia supply source through the ammonia supply pipeline 242. The ammonia supply regulating component 26 is disposed on the ammonia supply pipeline 242.

[0112] A primary ammonia distribution pipe 211 extends from the ammonia supply header 241 and connects to an ammonia collection box 212. The ammonia collection box 212 is fitted over the exterior of the primary cylinder 111. One or at least two sets of fuel nozzles 213 are disposed within the ammonia collection box 212 and located on the outer wall of the primary cylinder 111, protruding outward relative to the outer wall of the primary cylinder 111 and communicating with the interior of the primary cylinder 111 to inject primary ammonia gas into the primary ventilation duct 11. Different sets of fuel nozzles 213 may be arranged at intervals along the axial direction of the primary ventilation duct 11. The same set of fuel nozzles 213 may include one or at least two fuel nozzles 213 arranged at intervals along the circumference of the primary ventilation duct 11. The fuel nozzles 213 may be in various shapes such as circular, elliptical, square, or polygonal.

[0113] In this embodiment, the axial angle between the fuel nozzle 213 and the primary air duct 11 is 10° to 170° to organize the primary ammonia gas and the primary air in a co-current, counter-current, or perpendicular cross-flow state, thereby enhancing mixing efficiency and improving mixing effect. Furthermore, the radial angle between the fuel nozzle 213 and the primary air duct 11 is 0° to 85° on each side, so that the primary ammonia gas jet, after being ejected, forms a state of rotating and spreading forward, increasing the contact area with the primary air, thereby strengthening turbulence and promoting the mixing of primary ammonia gas and primary air.

[0114] The fuel nozzle 213 can inject primary ammonia gas at high speed into the primary air duct 11, achieving thorough mixing of primary ammonia gas and primary air. Furthermore, the mixing of primary ammonia gas and primary air can be enhanced by adjusting the injection angle of the fuel nozzle 213, eliminating the need for a separate ammonia cyclone separator. Moreover, the combination of the fuel nozzle 213 and the primary air cyclone separator 181 further improves the mixing effect of primary ammonia gas and primary air.

[0115] A central air duct 14 is coaxially arranged inside the primary air duct 11, and the ignition source 3 is located inside the central air duct 14. The ignition source 3 is an ignition device of various forms, such as a high-energy ignition gun, a gas gun, an oil gun, or a plasma ignition gun. Its end extends from the outlet of the central air duct 14 and is located downstream of the primary air cyclone separator 181, so that the ignition source 3 can ignite the premixed gas after the primary ammonia and primary air are mixed to form a premixed gas.

[0116] The central air duct 14 is connected to the air source via the central air channel 141 to introduce central air into the central air duct 14, providing the air required for combustion of the ignition source 3, cooling the ignition source 3, and promoting the ignition or combustion of primary ammonia. The central air channel 141 is equipped with a central air regulating component 142 to control the central air volume.

[0117] Multiple secondary ammonia distribution pipes 221 extend from the ammonia supply pipe 24 and are arranged at intervals along the radial outer side of the secondary air duct 12. Each secondary ammonia distribution pipe 221 has a nozzle 222 at its outlet end, and each nozzle 222 has several nozzles 223 (e.g., spray holes) arranged on its end face to spray secondary ammonia gas, allowing it to enter the radially inner combustion zone. The spray direction of the nozzles 223 is at an angle of 0° to 90° to the end face of the nozzle 222. The sprayed ammonia fuel velocity is higher than the flame propagation velocity, allowing it to mix rapidly with the inner secondary air and the central flame air, resulting in a rapid reaction. The nozzles 223 can be circular, elliptical, square, or polygonal, among other shapes. The number and / or size of the nozzles 223 on different nozzles 222 can be the same or different.

[0118] like Figure 1As shown, in this embodiment, the end of the nozzle 222 is at least partially downstream of the secondary flare 122 in the axial direction. However, it should be understood that the end of the nozzle 222 can also be located upstream of the secondary flare 122 in the axial direction. When the end of the nozzle 222 is at least partially downstream of the secondary flare 122 in the axial direction, it is more convenient to achieve the mixing of secondary ammonia gas and inner secondary air.

[0119] In this embodiment, the axial angle between the nozzle 222 and the ammonia burner 10 is 0° to 90°, and the radial angle between the nozzle 222 and the ammonia burner 10 is 0° to 180°. Specifically, as shown... Figure 2 As shown, in this embodiment, the secondary air duct 12 is equipped with eight secondary ammonia distribution devices 22. The nozzles 222 of these eight devices are oriented differently, including a first nozzle 224 and a second nozzle 225 whose nozzles are oriented along the axial direction of the secondary air duct 12, and a third nozzle 226 whose nozzles are oriented at an angle to both the axial and radial directions of the secondary air duct 12. Although the first nozzle 224 and the second nozzle 225 are both oriented along the axial direction of the secondary air duct 12, one is oriented radially inward and the other radially outward, thus their orientations are still different. Because the nozzles 222 have different orientations, secondary ammonia gas can be sprayed in different directions, which is beneficial for achieving a more thorough mixing of the secondary ammonia gas with the inner secondary air and the inner flame.

[0120] The ammonia burner 10 in this embodiment can organize a certain proportion of staged ammonia fuel and staged air for pre-mixing and staged combustion, so that the entire ammonia combustion zone forms a... Figure 3 The diagram shows the oxygen-enriched premixing zone 41, the partial recirculation burnout zone 42, the central oxygen-enriched main combustion zone 43, the staged combustion and nitrogen reduction zone 44, and the flue gas recirculation burnout zone 45.

[0121] During operation, pure ammonia fuel is fed into the ammonia burner 10 in two stages, and air is fed into the ammonia burner 10 in three stages. The two stages of ammonia fuel are primary ammonia and secondary ammonia, both originating from the ammonia supply header 241. The three stages of combustion air are central air, primary air, and secondary air. The secondary air comes from the bellows 15. The primary air and central air come from the bellows 15, or from other air sources.

[0122] Specifically, the ammonia in the ammonia supply main pipe 241 is divided into two parts. One part accounts for a larger proportion (e.g., 60% to 70%) and flows to the primary ammonia distribution pipe 211 as primary ammonia. The other part accounts for a smaller proportion and flows to each secondary ammonia distribution pipe 221 as secondary ammonia.

[0123] Among them, combined Figure 1 and Figure 3As can be seen, the primary ammonia gas entering the primary ammonia distribution pipe 211 flows into the ammonia collection box 212 and is sprayed into the primary air duct 11 through the fuel nozzle 213. It mixes with the primary air in the primary air duct 11 to form a premixed gas and creates an oxygen-rich and lean combustion atmosphere with an excess air coefficient greater than or equal to 1, making the primary air duct 11 an oxygen-rich premixed zone 41. The two gases swirl in opposite directions, mixing rapidly and thoroughly to form a premixed gas.

[0124] The premixed gas continues to flow axially downstream, passing through the primary cyclone separator 181, where it undergoes a rotating jet. Ignition source 3 ignites the rotating jet of premixed gas in the oxygen-enriched premixing zone 41, causing combustion. The resulting flame flows sequentially through the transition section 113 and the primary flare 112 before being ejected from the primary air duct 11. During the ignition process, due to the oxygen-enriched combustion atmosphere, ignition is rapid, and the primary ammonia gas is fully combusted.

[0125] The ejected airflow is recirculated under the action of the transition section 113 and the first-stage flare 112, forming a local recirculation burnout zone 42 near the outlet of the first-stage air duct 11. This can isolate the central oxygen-rich main combustion zone 43 and the staged combustion and nitrogen reduction zone 44 within a certain range. While achieving complete combustion and burnout of the first-stage ammonia, it also promotes the full cross-mixing of the outer staged airflow with the subsequently injected staged ammonia fuel, laying the foundation for the full reaction of the staged combustion and nitrogen reduction zone 44.

[0126] Furthermore, the ejected airflow continues forward, encountering the secondary air jetted from the secondary air duct 12, causing the primary ammonia flowing from the primary air duct 11 to continue burning. The added secondary air creates an oxygen-rich, lean-burn combustion atmosphere, forming a central oxygen-rich main combustion zone 43 downstream and inside the localized backflow burnout zone 42. The central oxygen-rich main combustion zone 43 is the main combustion area for the primary ammonia, and its interior has an oxygen-rich, lean-burn atmosphere, which is conducive to the rapid burnout of the primary ammonia and the rapid propagation of the combustion flame. At the same time, the NO content in the central oxygen-rich main combustion zone 43 can be adjusted by regulating the proportion of the staged air (i.e., secondary air). x Effective control of the amount generated.

[0127] Simultaneously, multiple secondary ammonia distribution units 22 supplement secondary ammonia gas, forming a large staged combustion and nitrogen reduction zone 44 radially outside and downstream of the central oxygen-enriched main combustion zone 43. The stable flame of the central oxygen-enriched main combustion zone 43 heats and ignites the injected staged ammonia fuel (i.e., secondary ammonia gas), reducing NO generated in the central oxygen-enriched zone while the staged ammonia fuel itself undergoes oxygen-deficient combustion. x This reduces NOx emissions from the ammonia burner 10.

[0128] In addition, under the action of primary wind, staged wind and staged ammonia fuel rotating jet, a flue gas recirculation burnout zone 45 is formed downstream of the central oxygen-enriched main combustion zone 43 and the staged combustion denitrification zone 44. A large amount of high-temperature flue gas is entrained and recirculated, and it is fully mixed with the combustion flame of the staged combustion denitrification zone 44. The high-temperature flue gas recirculation in the center of the boiler furnace is used to heat and burn the unburned ammonia fuel, and further supplement the air required for ammonia combustion, so as to achieve complete combustion of ammonia.

[0129] As can be seen, the ammonia burner 10 in this embodiment can premix a certain proportion of ammonia with a portion of air before ignition, and supplement the outer layer with secondary air to ensure stable ignition and complete combustion of the primary ammonia under oxygen-rich conditions. Then, by adjusting the specific ratio of secondary ammonia to staged air, a reducing combustion atmosphere is created in the outer layer, effectively suppressing NO during the combustion process. x The amount generated is reduced, and the pure ammonia is fully burned in the air.

[0130] Therefore, the ammonia burner 10 of this embodiment can control NO while achieving stable ignition, combustion, and complete burnout of ammonia. x This method effectively addresses two major technical issues associated with the combustion of pure ammonia as fuel. Specifically, the use of an oxygen-enriched combustion method during ignition facilitates the ignition and stable combustion of ammonia, accelerating the reaction rate of primary ammonia combustion, increasing the flame propagation speed, and thus promoting stable combustion of primary ammonia. Once the flame stabilizes, secondary air is introduced for mixing and combustion, creating an oxidizing combustion atmosphere that ensures complete combustion of primary ammonia. The subsequently injected secondary ammonia rapidly mixes and reacts with the staged air and the primary ammonia combustion flame, reducing NO₂ levels. x The amount of ammonia produced is increased, and the ammonia fuel is burned completely.

[0131] Moreover, the ammonia burner 10 in this embodiment is a pure ammonia burner, which does not require mixing of ammonia gas or pre-cracking of ammonia gas. Therefore, it has a simpler structure, lower cost, higher safety, and better carbon reduction effect.

[0132] As can be seen, the ammonia burner 10 of this embodiment can achieve rapid ignition and complete combustion of pure ammonia gas, as well as NO, based on a relatively simple structure, low cost, and high safety. x The emission reduction will facilitate the promotion and application of ammonia fuel and promote the further development of low-carbon combustion technology.

[0133] Because the ammonia burner 10 in this embodiment has a simple structure, complete functions, and good combustion effect, it can be widely used in different types of boilers in the power generation and petrochemical fields. With only low-cost combustion modifications to existing boilers, ammonia, a zero-carbon fuel, can partially or completely replace fossil fuels, achieving a significant reduction in CO2 emissions from thermal power generating units.

[0134] Accordingly, this application also provides a combustion system, which includes a boiler and an ammonia burner 10 according to an embodiment of this application.

[0135] In addition, based on the ammonia burner 10 of this application embodiment, this application also provides a combustion method, which includes:

[0136] Primary air is introduced into the primary air duct 11, and primary ammonia is introduced into the primary ammonia distribution device 21, so that the primary ammonia and primary air are mixed in the primary air duct 11 to form a premixed gas with an excess air coefficient greater than or equal to 1, and the premixed gas is ignited by the ignition source 3.

[0137] Secondary air is introduced into the secondary air duct 12 to spray the secondary air into the flame ejected from the primary air duct 11, so that the primary ammonia ejected from the primary air duct 11 can burn in an oxygen-rich atmosphere.

[0138] Secondary ammonia gas is introduced into the secondary ammonia distribution device 22 to spray the secondary ammonia gas into the radially inner flame, so that the secondary ammonia gas is burned in a reducing atmosphere.

[0139] It is understandable that the above three steps do not need to be performed in a strict order. For example, the introduction of primary air, primary ammonia, secondary air, and secondary ammonia can be performed simultaneously.

[0140] The above description is merely an exemplary embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An ammonia burner (10), characterized in that, include: A primary ventilation duct (11) is used to provide primary airflow; A primary ammonia distribution device (21) is coupled to the primary air duct (11) and primary ammonia gas is introduced into the primary air duct (11) so that the primary ammonia gas and the primary air are mixed in the primary air duct (11) to form a premixed gas with an excess air coefficient greater than or equal to 1. Ignition source (3) is used to ignite the premixed gas; A secondary air duct (12) is fitted outside the primary air duct (11) and is used to inject secondary air into the flames ejected from the primary air duct (11); and The secondary ammonia distribution device (22) is located on the radially outer side of the secondary air duct (12) to inject secondary ammonia gas into the flame on the radially inner side.

2. The ammonia burner (10) according to claim 1, characterized in that, The primary ventilation duct (11) includes a primary cylinder (111) and a primary flare (112), the primary flare (112) being connected to the outlet of the primary cylinder (111), and the flow area increasing along the outflow direction of the primary air; and / or, the secondary ventilation duct (12) includes a secondary cylinder (121) and a secondary flare (122), the secondary flare (122) being connected to the outlet of the secondary cylinder (121), and the flow area increasing along the outflow direction of the secondary air.

3. The ammonia burner (10) according to claim 2, characterized in that, The primary air duct (11) includes the primary cylinder (111) and the primary flare (112), and the primary air duct (11) includes a transition section (113), which connects the primary cylinder (111) and the primary flare (112), and the sidewall of the transition section (113) extends radially along the primary air duct (11).

4. The ammonia burner (10) according to claim 1, characterized in that, The ammonia burner (10) includes at least one of the following: A primary wind cyclone separator (181) is installed in the primary wind duct (11) and causes the primary wind to swirl and flow in the primary wind duct (11); A secondary cyclone separator (182) is installed in the secondary air duct (12) and causes the secondary cyclone to flow; A primary air regulating component (171) is provided on the air inlet path of the primary air duct (11) and regulates the air volume of the primary air entering the primary air duct (11); A secondary air conditioning component (172) is installed on the air inlet path of the secondary air duct (12) and adjusts the air volume of the secondary air entering the secondary air duct (12); An ammonia quantity regulating component (25) is installed on the primary ammonia distribution device (21) and / or the secondary ammonia distribution device (22) to regulate the amount of ammonia flowing into the primary ammonia distribution device (21) and / or the secondary ammonia distribution device (22).

5. The ammonia burner (10) according to claim 4, characterized in that, The ammonia burner (10) is configured to be at least one of the following: The angle between the swirl blades of the primary cyclone separator (181) and / or the secondary cyclone separator (182) and the axial direction of the primary wind tunnel (11) is 0° to 80°. The angle between the swirl blades of the primary cyclone separator (181) and / or the secondary cyclone separator (182) and the axial direction of the primary wind tunnel (11) is adjustable.

6. The ammonia burner (10) according to any one of claims 1-5, characterized in that, The primary ammonia distribution device (21) includes a fuel nozzle (213) connected to the primary air duct (11) to introduce primary ammonia gas into the primary air duct (11); and / or, the secondary ammonia distribution device (22) includes a secondary ammonia distribution pipe (221) and a nozzle (222), the secondary ammonia distribution pipe (221) being located radially outside the secondary air duct (12), and the nozzle (222) being connected to the outlet of the secondary ammonia distribution pipe (221) and connected to the secondary ammonia distribution pipe (221).

7. The ammonia burner (10) according to claim 6, characterized in that, The primary ammonia distribution device (21) includes an ammonia collection box (212) for connection to an ammonia supply source, and the fuel nozzle (213) is connected to the ammonia collection box (212); and / or, the ammonia burner (10) includes at least two secondary ammonia distribution devices (22), which are arranged circumferentially along the secondary air duct (12), and the nozzles (222) of the at least two secondary ammonia distribution devices (22) face the same or different directions.

8. The ammonia burner (10) according to claim 7, characterized in that, The at least two secondary ammonia distribution devices (22) include at least one of a secondary ammonia distribution device (22) with its nozzles oriented parallel to the axial direction of the primary air duct (11) and a secondary ammonia distribution device (22) with its nozzles oriented at an angle to the axial direction and / or radial direction of the primary air duct (11); and / or, the at least two secondary ammonia distribution devices (22) include at least one of a secondary ammonia distribution device (22) with its nozzles oriented radially inward of the primary air duct (11) and a secondary ammonia distribution device (22) with its nozzles oriented radially outward of the primary air duct (11).

9. The ammonia burner (10) according to claim 7, characterized in that, The angle between the orientation of the nozzle (222) and the axial direction of the primary air duct (11) is 0° to 90°, and / or the angle between the orientation of the nozzle (222) and the radial direction of the primary air duct (11) is 0° to 180°.

10. The ammonia burner (10) according to claim 6, characterized in that, The fuel nozzle (213) is configured as at least one of the following: The fuel nozzle (213) is disposed on the side wall of the primary air duct (11); The angle between the jet direction of the fuel nozzle (213) and the axis of the first-stage air duct (11) is 10° to 170°. The angle between the jet direction of the fuel nozzle (213) and the radial direction of the primary air duct (11) is 0° to 85°.

11. The ammonia burner (10) according to any one of claims 1-5, characterized in that, The primary ventilation duct (11) is provided with a central ventilation duct (14), which provides central airflow, and the ignition source (3) extends into the central ventilation duct (14).

12. The ammonia burner (10) according to claim 11, characterized in that, The central air duct (14) is provided with a central air regulating component (142) in the air inlet flow path, and the central air regulating component (142) regulates the air volume of the central air entering the central air duct (14).

13. A combustion system, comprising a boiler, characterized in that, Includes the ammonia burner (10) as described in any one of claims 1-12.

14. A combustion method based on an ammonia burner (10) as described in any one of claims 1-13, characterized in that, include: Primary air is introduced into the primary air duct (11), and primary ammonia is introduced into the primary ammonia distribution device (21) so that the primary ammonia and the primary air are mixed in the primary air duct (11) to form a premixed gas with an excess air coefficient greater than or equal to 1, and the premixed gas is ignited using the ignition source (3). Secondary air is introduced into the secondary air duct (12) to spray the secondary air into the flame ejected from the primary air duct (11), so that the primary ammonia ejected from the primary air duct (11) is burned in an oxygen-rich atmosphere; Secondary ammonia gas is introduced into the secondary ammonia distribution device (22) to spray the secondary ammonia gas into the flame on the radially inner side, so that the secondary ammonia gas is burned in a reducing atmosphere.

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