Ammonia-blended swirl burner with multi-channel ammonia fuel pipe

Abstract

The present invention discloses an ammonia-blended swirl burner with a multi-channel ammonia fuel pipe, which belongs to the technical field of burners. By arranging an ammonia fuel pipe assembly composed of an outer ammonia fuel pipe, an inner ammonia fuel pipe and an end ammonia fuel pipe in a primary air duct, the reliable and safe transportation of ammonia fuel in the swirl burner can be realized; and by setting the outlet of the ammonia fuel to a structure extending a certain distance from the outlet of the primary air duct, in combination with the trumpet-shaped outlet section at the end of the primary air duct and the flow-guiding refractory mechanism, the safe low-nitrogen and efficient combustion of ammonia fuel after being transported in the burner can be realized. The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe in the present invention has a compact structure and is easy to use. It can not only ensure the air tightness of the ammonia channel, but also flexibly adjust the incident position and incident speed of ammonia, effectively realize the efficient and low-nitrogen combined combustion of coal powder and ammonia fuel, improve the environmental protection of coal-fired boilers during use, and reduce the operating cost of coal-fired boilers, and has good practical value.

Description

Technical Field

[0001] The invention belongs to the technical field of burners, and in particular relates to an ammonia-blended swirl burner with a multi-channel ammonia fuel pipe. Background Art

[0002] In order to reduce carbon emissions caused by coal burning, a common practice in existing technologies is to use new renewable resources to replace or partially replace traditional fossil energy. For example, new zero-carbon fuels such as ammonia are used to replace coal to achieve coal-ammonia co-combustion.

[0003] Co-combustion of coal and ammonia generally has the following advantages: (1) Environmental protection and emission reduction. The use of mixed ammonia combustion technology can effectively reduce the emissions of pollutants such as sulfur dioxide and nitrogen oxides from coal-fired boilers, thereby achieving the goal of environmental protection and emission reduction; (2) Improving combustion efficiency. The use of mixed ammonia combustion technology can make the combustion process more complete and the combustion temperature higher, thereby improving combustion efficiency and reducing energy consumption; (3) Reducing operating costs. The use of mixed ammonia combustion technology can reduce the emissions of pollutants generated by combustion and reduce environmental protection management costs. At the same time, it can also improve combustion efficiency and reduce energy consumption, thereby reducing operating costs; (4) Wide range of applications. Mixed ammonia combustion technology can be applied to various types of coal-fired boilers, whether small or large coal-fired boilers.

[0004] However, compared with conventional hydrocarbon fuels, ammonia has a lower calorific value, a narrow flammability limit range, and a low flame speed, and there are problems of difficulty in ignition and unstable combustion; especially as a nitrogen-containing fuel, ammonia also has the risk of high NOx emissions. Based on this, in order to use ammonia as a fuel in power plants and obtain better ignition, stable combustion, burnout and NOx emission characteristics, the structural design of the burner is crucial. However, in the prior art, although there are some boilers or burners for ammonia-blended combustion, such as those shown in Chinese patent documents CN107477573B, CN113623653B, etc., the control mode of the above-mentioned burners is often relatively simple, and the related structure is relatively complex, and the regulation mode is cumbersome, and it is difficult to reliably meet the needs of practical applications. Summary of the invention

[0005] In view of one or more of the above defects or improvement needs of the prior art, the present invention provides an ammonia-blended swirl burner with a multi-channel ammonia fuel pipe, which can effectively solve the problems of the existing ammonia-blended burners, such as poor adjustable ammonia combustion position and injection speed, and NO x There are problems such as complex emission control methods and complex burner structure.

[0006] To achieve the above object, the present invention provides an ammonia-blended swirl burner with a multi-channel ammonia fuel pipe, comprising a primary air component with a primary air duct and a secondary air component arranged at the periphery of the end of the primary air component;

[0007] One end of the primary air duct close to the burner outlet is arranged as a trumpet-shaped outlet section whose inner diameter increases successively along the primary air conveying direction, and a flow-guiding refractory mechanism is coaxially arranged in the trumpet-shaped outlet section; the flow-guiding refractory mechanism is a frustum structure, whose outer diameter increases successively along the primary air conveying direction, and an annular cavity for primary air to pass through is formed between the outer periphery of the flow-guiding refractory mechanism and the inner wall surface of the trumpet-shaped outlet section; and

[0008] An ammonia fuel pipe assembly is also provided in the primary air duct, which includes an outer ammonia fuel pipe coaxially arranged with the trumpet-shaped outlet section; one end of the outer ammonia fuel pipe extends out of the primary air duct, and the other end thereof extends to the trumpet-shaped outlet section and is connected to the small-diameter end of the flow-guiding refractory mechanism;

[0009] An inner ammonia fuel pipe is coaxially passed through the outer ammonia fuel pipe; an inner channel for transporting ammonia fuel is formed in the inner ammonia fuel pipe, and both ends of the inner channel pass through the outer ammonia fuel pipe respectively, and the outlet end of the inner ammonia fuel pipe having an inner channel outlet extends a certain distance from the outlet of the primary air duct; and

[0010] An end ammonia fuel pipe is coaxially sleeved on the outer periphery of the outlet end of the inner ammonia fuel pipe, the outlet end of which is fixedly connected to the outlet end of the inner ammonia fuel pipe, and the other end passes through the flow-guiding fire-resistant structure and extends into the outer ammonia fuel pipe, so that an outer channel connected to the outer ammonia fuel pipe is formed between the end ammonia fuel pipe and the inner ammonia fuel pipe, and an outer channel outlet is formed at the outlet end of the end ammonia fuel pipe;

[0011] Correspondingly, an inner ammonia fuel inlet is formed at one end of the inner ammonia fuel pipe away from the primary air outlet, and an outer ammonia fuel inlet is formed at the end of the outer ammonia fuel pipe extending out of the primary air pipe.

[0012] As a further improvement of the present invention, a displacement mechanism is provided corresponding to the end of the inner ammonia fuel pipe away from the primary air outlet, which is used to drive the inner ammonia fuel pipe and the end ammonia fuel pipe to perform synchronous axial displacement to change the positions of the outer channel outlet and the inner channel outlet relative to the primary air outlet.

[0013] As a further improvement of the present invention, the displacement mechanism is an adjusting motor, and the end of the inner ammonia fuel pipe is arranged as a threaded fixing section;

[0014] The threaded fixing section is threadedly connected to the end of the outer ammonia fuel pipe and assembled with the output end of the regulating motor, so that the inner ammonia fuel pipe can be axially displaced under the control of the regulating motor.

[0015] As a further improvement of the present invention, an internal thread section is provided on the inner peripheral wall surface of the outer ammonia fuel pipe, and the outer periphery of the end of the end ammonia fuel pipe extending into the outer ammonia fuel pipe is threadedly connected with the internal thread section.

[0016] As a further improvement of the present invention, the primary air duct includes a primary air conveying section and a trumpet-shaped outlet section, and at least one concentrating section with a diameter that first decreases and then increases is provided therebetween for guiding and concentrating coal powder in the primary air duct.

[0017] As a further improvement of the present invention, the concentration pipe section is provided with two, each of which is formed by a primary air concentration section and a primary air concentration ring being combined and provided;

[0018] The primary air concentration section is arranged at the front end of the primary air concentration ring, one end of which has a gradually decreasing inner diameter is connected to the primary air conveying section, and the other end of which has a gradually increasing inner diameter is connected to the pipe section where the primary air concentration ring is arranged;

[0019] The primary air concentration ring is arranged on the inner periphery of the pipe section and is a suddenly contracting and gradually expanding tubular structure.

[0020] As a further improvement of the present invention, the minimum inner diameter of the primary air concentration ring is smaller than the minimum inner diameter of the primary air concentration section.

[0021] As a further improvement of the present invention, the middle parts of the primary air concentration section and the primary air concentration ring are respectively formed with straight sections of a certain length, and the inner diameters of the straight sections are kept constant.

[0022] As a further improvement of the present invention, the angle between the outer conical surface of the diversion refractory mechanism and its axis is 10° to 30°;

[0023] Correspondingly, the angle between the inner wall surface of the trumpet-shaped outlet section and its axis is 10° to 30°.

[0024] As a further improvement of the present invention, the secondary air component includes an inner swirl channel and an outer swirl channel arranged in sequence from the inside to the outside on the outer periphery of the primary air duct outlet end; secondary air bellows and secondary air swirl blades are respectively arranged corresponding to the two swirl channels.

[0025] The above-mentioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0026] In general, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:

[0027] (1) The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe in the present invention can realize reliable transportation of ammonia fuel in the swirl burner by arranging an ammonia fuel pipe assembly consisting of an outer ammonia fuel pipe, an inner ammonia fuel pipe and an end ammonia fuel pipe in the primary air duct; and by arranging the outlet of the ammonia fuel to extend a certain distance from the outlet of the primary air duct, and coordinating the trumpet-shaped outlet section at the end of the primary air duct and the guide refractory mechanism, a central recirculation zone is formed in the middle of the burner outlet and an oxygen-rich zone is formed at the periphery of the outlet, which effectively avoids the ammonia fuel from being drawn into the oxygen-rich zone of coal combustion during ammonia-blended combustion, inhibits the oxidation of the ammonia fuel, promotes the thermal decomposition of ammonia, and reduces NO x The generation of ammonia ensures the efficiency of ammonia combustion.

[0028] (2) The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe in the present invention has a displacement mechanism for the inner ammonia fuel pipe in the ammonia fuel pipe assembly, thereby realizing displacement adjustment of the inner ammonia fuel pipe, thereby changing the positions of the outer channel outlet and the inner channel outlet relative to the primary air outlet, thereby meeting the ammonia-blended combustion under different combustion conditions, improving the adaptability and application range of the swirl burner, ensuring the ammonia-blended combustion of the burner under different combustion loads, and improving the reliability and stability of the ammonia-blended combustion of the burner.

[0029] (3) The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe in the present invention is configured such that the fuel pipe connection in the ammonia fuel pipe assembly is a threaded connection, that is, the connection between the inner ammonia fuel pipe and the outer ammonia fuel pipe, and between the end ammonia fuel pipe and the outer ammonia fuel pipe are threaded connections, and the combination of the adjusting motor is configured so that the inner ammonia fuel pipe can realize the axial displacement of itself and the end ammonia fuel pipe at the same time through rotation, thereby changing the distance that the inner and outer ammonia fuel outlets extend out of the primary air outlet. While realizing the ammonia fuel spraying position, it fully guarantees the sealing and reliability of the ammonia fuel transportation process and avoids leakage during the ammonia fuel transportation process.

[0030] (4) The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe in the present invention is configured with at least one concentrating pipe section on the conveying path of the primary air duct, so that the pulverized coal conveyed by the primary air can be concentrated in the concentrating pipe section, thereby increasing the pulverized coal concentration in the central area, thereby improving the combustion stability of the burner under low-load operation, ensuring the full combustion of the pulverized coal, and improving the combustion efficiency.

[0031] (5) The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe in the present invention has a compact structure and is easy to use. It can not only ensure the airtightness of the ammonia channel, but also flexibly adjust the ammonia gas incident position and incident speed, effectively realize the high-efficiency and low-nitrogen combined combustion of coal powder and ammonia fuel, improve the environmental protection of coal-fired boilers during use, and reduce the operating costs of coal-fired boilers. It has good practical value and application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 is a schematic diagram of the structure of an ammonia-doped swirl burner according to an embodiment of the present invention;

[0034] Figure 2 is a schematic diagram of the principle of an ammonia-doped swirl burner in an embodiment of the present invention;

[0035] Figure 3 is a schematic diagram of the simulated velocity of the ammonia-doped swirl burner according to an embodiment of the present invention;

[0036] Figure 4 Schematic diagram of simulated combustion temperature of an ammonia-doped swirl burner according to an embodiment of the present invention;

[0037] Figure 5 is the simulated NO of the ammonia-doped swirl burner in the embodiment of the present invention. x Concentration diagram;

[0038] Figure 6 is a schematic diagram of parameter statistics results of the ammonia fuel pipe assembly under different control states in an embodiment of the present invention;

[0039] In all the drawings, the same reference numerals represent the same technical features, specifically:

[0040] 1. Primary air assembly; 101. Primary air inlet; 102. Primary air conveying section; 103. Primary air concentration section; 104. Primary air concentration ring; 105. Primary air outlet; 106. Guide refractory mechanism;

[0041] 2. Ammonia fuel pipe assembly; 201. Inner ammonia fuel pipe; 2011. Threaded fixed section; 2012. Straight pipe section; 202. Outer ammonia fuel pipe; 2021. Internal threaded section; 203. End ammonia fuel pipe; 204. Inner channel outlet; 205. Outer channel outlet; 206. Inner ammonia fuel inlet; 207. Outer ammonia fuel inlet; 208. Adjusting motor;

[0042] 3. Secondary air assembly; 301. Inner secondary air bellows; 302. Inner secondary air swirl blades; 303. Outer secondary air bellows; 304. Outer secondary air swirl blades. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0044] In the description of the present invention, it should be understood that, unless otherwise expressly specified and limited, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0045] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0046] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0048] Example:

[0049] See also Figure 1 The ammonia-blended swirl burner in the preferred embodiment of the present invention has a multi-channel and position-adjustable ammonia fuel pipe, that is, Figure 1 The ammonia fuel pipe assembly 2 shown in FIG.

[0050] Specifically, the ammonia-blended swirl burner in the preferred embodiment includes a primary air component 1, which has a primary air duct, and the primary air duct includes a primary air delivery section 102 and a trumpet-shaped outlet section arranged at the end; wherein one end of the primary air delivery section 102 is connected to the primary air inlet 101, and the other end thereof extends to the outlet side of the burner and is connected to the trumpet-shaped outlet section. Accordingly, the inner diameter of the trumpet-shaped outlet section increases successively along the primary air delivery direction (transmitted from the primary air inlet 101 to the burner outlet).

[0051] At the same time, a guide refractory structure 106 is coaxially arranged in the trumpet-shaped outlet section of the primary air duct. The guide refractory structure 106 is preferably made of refractory material and has a frustum structure. Its outer diameter increases gradually along the primary air conveying direction, and an annular cavity with gradually increasing inner and outer diameters is formed between the outer periphery of the guide refractory structure 106 and the inner wall surface of the primary air duct (trumpet-shaped outlet section).

[0052] By utilizing the trumpet-shaped structure at the end of the primary air duct and the setting of the conical guide refractory structure 106, the primary air and material (coal powder) at the primary air outlet 105 can be transported to the peripheral area at the outlet, and a high oxygen zone is formed in the peripheral area of ​​the burner outlet, and a central recirculation zone is formed in the central area of ​​the outlet on one side of the guide refractory structure 106.

[0053] Preferably, in actual setting, in order to achieve the diversion and concentration of coal powder in the primary air duct, at least one concentration pipe section with a diameter that is first reduced and then expanded is provided on the transmission path of the primary air duct, which is arranged between the primary air conveying section 102 and the trumpet-shaped opening section.

[0054] For example, in Figure 1 In the preferred embodiment shown, there are two concentrating pipe sections, which are respectively formed by the combination of the primary air concentrating section 103 and the primary air concentrating ring 104. The primary air concentrating section 103 is composed of a gradually contracting part and a gradually expanding part successively arranged along the primary air conveying direction, that is, the primary air concentrating section 103 is a gradually contracting and gradually expanding tubular structure, which can preliminarily concentrate the coal powder in the primary air.

[0055] At the same time, the primary air concentration ring 104 in the preferred embodiment is arranged inside the primary air duct, and is a tubular structure with a variable inner diameter, and has a sudden contraction portion and a gradual expansion portion arranged successively along the primary air conveying direction, that is, the primary air concentration ring 104 is a sudden contraction and gradual expansion tubular structure (the inner diameter reduction value of the sudden contraction portion per unit length is greater than the inner diameter increase value of the gradual expansion portion per unit length). With the above arrangement, the material conveyed in the primary air can be secondary concentrated, and the stability of the conveying of the concentrated material can be fully guaranteed.

[0056] It can be understood that in actual settings, the minimum inner diameter of the primary air concentration ring 104 is smaller than the minimum inner diameter of the primary air concentration section 103. Such a setting can realize the double concentration process of coal powder, increase the coal powder concentration at the burner outlet, and ensure the stability of the primary air transportation process.

[0057] In the specific setting, the above two concentration pipe sections can be set at the same time, or only one of them can be set. Moreover, in the actual setting, the setting of the primary air concentration ring 104 can also be changed to the modification of the structure of the primary air duct itself, that is, a pipe body with a "sudden contraction and gradual expansion" of the inner diameter of the pipe is formed between the primary air conveying section 102 and the primary air outlet 105, which will not be repeated here.

[0058] In addition, in the actual setting, in order to ensure the reliability of the diversion and transportation during the concentration process, a straight section of a certain length is preferably provided before the gradually expanding part of the two concentration pipe sections. In the straight section, the inner diameter of the pipe section is kept constant, so as to further stabilize the material transmission state after concentration, avoid the formation of turbulence in the primary air duct, and ensure the stability of coal powder material transmission.

[0059] Furthermore, in the specific configuration, the angle between the outer conical surface of the flow-guiding refractory structure 106 and its axis is preferably set to 10° to 30°. Correspondingly, the angle between the inner wall surface of the trumpet-shaped outlet section and the axis of the primary air duct is also preferably 10° to 30°.

[0060] like Figure 1 As shown in the figure, the primary air assembly 1 in the preferred embodiment is also provided with an ammonia fuel pipe assembly 2, which includes an outer ammonia fuel pipe 202 passing through the primary air duct, an inner ammonia fuel pipe 201 coaxially passing through the outer ammonia fuel pipe 202, and an end ammonia fuel pipe 203 coaxially sleeved on the outer periphery of the end of the inner ammonia fuel pipe 201.

[0061] Specifically, one end of the outer ammonia fuel pipe 202 is located outside the primary air duct, and the other end thereof coaxially extends into the primary air conveying section 102, and is connected to the small diameter end of the guide refractory mechanism 106 at its end after extending to the trumpet-shaped outlet section.

[0062] At the same time, the inner ammonia fuel pipe 201 in the preferred embodiment is coaxially arranged in the outer ammonia fuel pipe 202, and its inlet end passes through the end of the outer ammonia fuel pipe 202. The inlet end is a threaded fixing section 2011, and is assembled corresponding to the output end of the adjusting motor 208, so that the adjusting motor 208 can drive the inner ammonia fuel pipe 201 to perform axial reciprocating motion.

[0063] In a preferred embodiment, the inlet end of the inner ammonia fuel pipe 201 is set as a threaded fixed section 2011, which is threadedly connected to the end of the outer ammonia fuel pipe 202 and assembled with the output end of the adjusting motor 208. The rotation of the inner ammonia fuel pipe 201 is achieved by driving the adjusting motor 208, thereby achieving adjustment of the axial position of the inner channel outlet 204, and improving the sealing and reliability of the assembly connection between the inner ammonia fuel pipe 201 and the outer ammonia fuel pipe 202.

[0064] Accordingly, the middle part and the outlet end of the inner ammonia fuel pipe 201 are set as a straight pipe section 2012, and the inner channel mentioned above is formed inside the inner ammonia fuel pipe 201 for conveying a part of the ammonia fuel. At the same time, an inner ammonia fuel inlet 206 is formed at one end of the inner ammonia fuel pipe 201 connected to the regulating motor 208, and the other end thereof extends a certain distance from the air outlet of the primary air duct and forms an inner channel outlet 204.

[0065] In detail, in actual configuration, the inner channel outlet 204 preferably extends to the rear of the central recirculation zone. More specifically, in a preferred embodiment, the inner ammonia fuel pipe 201 extends from the primary air outlet 105 by a distance of preferably 0.4 to 1.2 m, which is the same as the CO, H2, NO x The relationship is as follows Figure 6 as shown in .

[0066] It can be understood that, in actual settings, the axial displacement drive of the inner ammonia fuel pipe 201 is not limited to the above-mentioned method, and it can also be set to other displacement mechanisms as needed; for example, a linear motor is set to be assembled with the end of the inner ammonia fuel pipe 201, and then the displacement drive of the inner ammonia fuel pipe 201 is completed through the telescopic control of the linear motor output shaft.

[0067] Furthermore, the end ammonia fuel pipe 203 in the preferred embodiment is coaxially sleeved on the outer periphery of the outlet end of the inner ammonia fuel pipe 201, and its length is smaller than the length of the inner ammonia fuel pipe 201. One end thereof passes through the flow-guiding refractory structure 106 and extends into the outer ammonia fuel pipe 202, and the other end is fixedly connected to the end of the inner ammonia fuel pipe 201.

[0068] It can be understood that, through the above arrangement, the distance that the end ammonia fuel pipe 203 extends out of the primary air outlet 105 is equal to the distance that the inner ammonia fuel pipe 201 extends out of the primary air outlet 105 .

[0069] After the above arrangement is completed, a tubular structure in an annular shape connected to the outer ammonia fuel pipe 202 is formed between the end ammonia fuel pipe 203 and the inner ammonia fuel pipe 201, that is, an outer channel is formed for conveying another part of the ammonia fuel. Accordingly, an outer channel outlet 205 is formed at the end of the end ammonia fuel pipe 203 fixedly connected to the inner ammonia fuel pipe 201 to realize the output of the outer ammonia fuel.

[0070] More specifically, in actual arrangement, the end ammonia fuel pipe 203 is thread-matched with the internal thread section 2021 arranged on the inner peripheral wall surface of the middle part of the outer ammonia fuel pipe 202. Accordingly, the pitch of the internal thread section 2021 is the same as the pitch of the thread fixing section 2011, and the other end of the end ammonia fuel pipe 203 is fixedly connected to the outlet end of the inner ammonia fuel pipe 201, so that the end ammonia fuel pipe 203 can rotate synchronously with the inner ammonia fuel pipe 201, and the axial relative position adjustment of the outer channel outlet 205 and the outer ammonia fuel pipe 202 is achieved.

[0071] By using the threaded connection between one end of the end ammonia fuel pipe 203 and the outer ammonia fuel pipe 202, the sealing of the connection between the two fuel pipes can be effectively guaranteed, preventing the outer ammonia fuel from entering between the end ammonia fuel pipe 203 and the outer ammonia fuel pipe 202, thereby ensuring that the ammonia fuel is only output from the inner channel outlet 204 and the outer channel outlet 205.

[0072] It can be understood that in order to realize the input of external ammonia fuel, an external ammonia fuel inlet 207 is provided at the end of the external ammonia fuel pipe 202 extending out of the primary air duct to introduce the ammonia fuel into the annular cavity between the internal ammonia fuel pipe 201 and the external ammonia fuel pipe 202 .

[0073] Further preferably, in order to ensure sufficient combustion of the pulverized coal in the peripheral area of ​​the burner outlet, a secondary air component 3 is also provided at the periphery of the outlet section of the primary air duct, such as Figure 1 As shown in the figure, it includes an inner swirl channel and an outer swirl channel arranged in sequence from the inside to the outside at the outer periphery of the primary air duct outlet end. The inner swirl channel is arranged at the outer periphery of the primary air duct outlet end in an annular structure; correspondingly, the outer swirl channel is arranged at the outer periphery of the inner swirl channel in a corresponding annular structure.

[0074] Specifically, an inner secondary air box 301 and an inner secondary air swirl blade 302 are provided corresponding to the inner swirl channel. By providing the inner secondary air swirl blade 302, the inner swirl secondary air can be continuously transported to the outer periphery of the opening side of the primary air duct through the inner swirl channel.

[0075] In more detail, an outer secondary air box 303 and an outer secondary air swirl blade 304 are provided corresponding to the outer swirl channel. By providing the outer secondary air swirl blade 304, the outer swirl secondary air can be continuously transported to the outer periphery of the opening side of the primary air duct through the outer swirl channel.

[0076] By using the above arrangement, an oxygen-rich zone of a certain length can be formed in the peripheral area of ​​the outlet of the primary air duct, so that the pulverized coal concentrated in the primary air duct can achieve oxygen-rich combustion in the peripheral area of ​​the outlet, fully ensuring the stability of the root of the pulverized coal flame.

[0077] By utilizing the above-mentioned combination arrangement of the primary air component 1 and the secondary air component 3, a central recirculation zone can be formed in the central area of ​​the burner outlet, and the high oxygen zone (oxygen-rich zone) can be "isolated" at the periphery of the outlet area.

[0078] Accordingly, by utilizing the above-mentioned setting of the ammonia fuel pipe assembly 2, the ammonia fuel can be accurately delivered to the burner, and in combination with the inner ammonia fuel pipe 201 and the end ammonia fuel pipe 203 extending at the end of the primary air duct, and the guide refractory mechanism 106 at the outlet of the primary air duct and the trumpet-shaped outlet section, the output position of the ammonia fuel can be located after the central reflux zone, away from the oxygen-rich zone at the periphery of the burner outlet, thereby preventing the ammonia fuel from being sucked into the primary air outlet 105 of the burner, thereby effectively inhibiting the oxidation reaction of ammonia, promoting the thermal decomposition of ammonia, ensuring the combustion efficiency of ammonia and controlling NO x Generation of.

[0079] In actual use, by adjusting the ammonia fuel flow in the inner and outer ammonia fuel pipes, the ammonia fuel injection speed at the outer channel outlet 205 and the inner channel outlet 204 of the ammonia fuel pipe assembly 2 can be adjusted. The specific adjustment process is as follows:

[0080] When the amount of ammonia blended is relatively small, the flow rate of the inner ammonia fuel inlet 206 is increased as much as possible, and the flow rate of the outer ammonia fuel inlet 207 is reduced, so as to increase the injection speed and injection momentum of the inner channel outlet 204 of the ammonia fuel pipe assembly 2;

[0081] When the amount of ammonia blended is relatively large, while ensuring the flow rate of the inner ammonia fuel inlet 206, the flow rate of the outer ammonia fuel inlet 207 can be appropriately increased to avoid the outlet area of ​​the ammonia fuel pipe assembly 2 being too far due to the overall ammonia flow rate being too large, thereby reducing the combustion efficiency of ammonia.

[0082] For the ammonia-doped swirl burner in the preferred embodiment, its actual use state is as follows: Figure 3~Figure 5 As shown in , a solid fuel ignition and combustion zone (peripheral area of ​​the burner outlet), an ammonia pyrolysis zone (behind the central recirculation zone), an ammonia / solid fuel mixed combustion zone, and an ammonia / solid fuel burnout zone can be formed at the burner outlet.

[0083] Among them, in the solid fuel ignition and combustion zone, the primary air fuel airflow is quickly preheated, volatiles are released, ignited, and coke is burned under the action of the recirculating flue gas, which preferentially consumes a large amount of oxygen and also provides heat for the thermal decomposition of the ammonia fuel; after the ammonia fuel is sent to the tail / rear area of ​​the central recirculation zone, it is directly sprayed into the low-oxygen and high-temperature area downstream of the recirculation zone, avoiding the ammonia fuel from flowing back to the primary air outlet area under the action of flue gas entrainment, thereby achieving the purpose of inhibiting the ammonia fuel from directly contacting with oxygen to produce an oxidation reaction and thus controlling the formation of nitrogen oxides; the ammonia fuel is fully thermally decomposed into hydrogen in the high-temperature and low-oxygen reducing atmosphere after the recirculation zone, and is fully mixed with the solid fuel volatiles / coke and oxygen to burn and burn out, thereby effectively realizing the ammonia-blended combustion of coal powder.

[0084] The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe in the present invention has a compact structure and is easy to use. It can effectively realize the combined combustion of coal powder and ammonia fuel, reduce the use of coal powder, effectively reduce carbon emissions and emissions of pollutants such as sulfur dioxide and nitrogen oxides, improve the environmental protection of coal-fired boilers during use, and reduce the operating costs of coal-fired boilers. It has good practical value and application prospects.

[0085] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An ammonia-blended swirl burner with a multi-channel ammonia fuel pipe, comprising a primary air component with a primary air duct and a secondary air component arranged at the periphery of the end of the primary air component; characterized in that: One end of the primary air duct close to the burner outlet is arranged as a trumpet-shaped outlet section whose inner diameter increases successively along the primary air conveying direction, and a flow-guiding refractory mechanism is coaxially arranged in the trumpet-shaped outlet section; the flow-guiding refractory mechanism is a frustum structure, whose outer diameter increases successively along the primary air conveying direction, and an annular cavity for primary air to pass through is formed between the outer periphery of the flow-guiding refractory mechanism and the inner wall surface of the trumpet-shaped outlet section; and An ammonia fuel pipe assembly is also provided in the primary air duct, which includes an outer ammonia fuel pipe coaxially arranged with the trumpet-shaped outlet section; one end of the outer ammonia fuel pipe extends out of the primary air duct, and the other end thereof extends to the trumpet-shaped outlet section and is connected to the small-diameter end of the flow-guiding refractory mechanism; An inner ammonia fuel pipe is coaxially passed through the outer ammonia fuel pipe; an inner channel for transporting ammonia fuel is formed in the inner ammonia fuel pipe, and both ends of the inner channel pass through the outer ammonia fuel pipe respectively, and the outlet end of the inner ammonia fuel pipe having an inner channel outlet extends a certain distance from the outlet of the primary air duct; and An end ammonia fuel pipe is coaxially sleeved on the outer periphery of the outlet end of the inner ammonia fuel pipe, the outlet end of which is fixedly connected to the outlet end of the inner ammonia fuel pipe, and the other end passes through the flow-guiding fire-resistant structure and extends into the outer ammonia fuel pipe, so that an outer channel connected to the outer ammonia fuel pipe is formed between the end ammonia fuel pipe and the inner ammonia fuel pipe, and an outer channel outlet is formed at the outlet end of the end ammonia fuel pipe; Correspondingly, an inner ammonia fuel inlet is formed at one end of the inner ammonia fuel pipe away from the primary air outlet, and an outer ammonia fuel inlet is formed at the end of the outer ammonia fuel pipe extending out of the primary air pipe.

2. The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe according to claim 1, characterized in that: A displacement mechanism is provided corresponding to the end of the inner ammonia fuel pipe away from the primary air outlet, which is used to drive the inner ammonia fuel pipe and the end ammonia fuel pipe to perform synchronous axial displacement to change the positions of the outer channel outlet and the inner channel outlet relative to the primary air outlet.

3. The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe according to claim 2, characterized in that: The displacement mechanism is an adjusting motor, and the end of the inner ammonia fuel pipe is arranged as a threaded fixing section; The threaded fixing section is threadedly connected to the end of the outer ammonia fuel pipe and assembled with the output end of the regulating motor, so that the inner ammonia fuel pipe can be axially displaced under the control of the regulating motor.

4. The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe according to claim 3, characterized in that: An internal thread section is arranged on the inner peripheral wall surface of the outer ammonia fuel pipe, and the outer periphery of the end portion of the end ammonia fuel pipe extending into the outer ammonia fuel pipe is threadedly connected with the internal thread section.

5. The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe according to any one of claims 1 to 4, characterized in that: The primary air duct comprises a primary air conveying section and a trumpet-shaped outlet section, and at least one concentrating section whose diameter is first reduced and then expanded is arranged between the primary air duct and is used for guiding and concentrating coal powder in the primary air duct.

6. The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe according to claim 5, characterized in that: The concentration pipe sections are provided in two, each of which is formed by a primary air concentration section and a primary air concentration ring being combined and arranged; The primary air concentration section is arranged at the front end of the primary air concentration ring, one end of which has a gradually decreasing inner diameter is connected to the primary air conveying section, and the other end of which has a gradually increasing inner diameter is connected to the pipe section where the primary air concentration ring is arranged; The primary air concentration ring is arranged on the inner periphery of the pipe section and is a suddenly contracting and gradually expanding tubular structure.

7. The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe according to claim 6, characterized in that: The minimum inner diameter of the primary air concentration ring is smaller than the minimum inner diameter of the primary air concentration section.

8. The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe according to claim 6 or 7, characterized in that: A straight section of a certain length is formed in the middle of the primary air concentration section and the primary air concentration ring, respectively, and the inner diameter of the straight section remains constant.

9. The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe according to any one of claims 1 to 4, 6 and 7, characterized in that: The angle between the outer conical surface of the diversion refractory structure and its axis is 10° to 30°; Correspondingly, the angle between the inner wall surface of the trumpet-shaped outlet section and its axis is 10° to 30°.

10. The ammonia-blended swirl burner with a multi-channel ammonia fuel pipe according to any one of claims 1 to 4, 6 and 7, characterized in that: The secondary air component comprises an inner swirl channel and an outer swirl channel which are arranged in sequence from the inside to the outside on the outer periphery of the primary air duct outlet end; a secondary air bellows and a secondary air swirl blade are respectively arranged corresponding to the two swirl channels.

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