Multi-axial coal dust combustion device

Abstract

The present application relates to the technical field of coal powder burner, in particular to a multi-shaft coal powder combustion device, which comprises a main structure cylinder, coal powder inlets and combustion ports are respectively arranged at both ends of the main structure cylinder; first air ducts and second air ducts are respectively arranged in the main structure cylinder, and the end nozzles of the first air ducts and the second air ducts are located at the combustion ports; cyclones are arranged at the end nozzles of the first air ducts. Compared with the prior art, the present application supplies oxygen for coal powder combustion through the first air ducts and the second air ducts, the end nozzles of the first air ducts are provided with cyclones, which are responsible for supplying oxygen for the flame near the combustion port, and the end nozzles of the second air ducts are high-speed jetted to a far place, which is responsible for supplying oxygen for the flame far away, so that the scale of the torch is effectively reduced, the large high-temperature area of the single torch is largely eliminated, and the generation of nitrogen oxide pollution is reduced.

Description

Technical Field

[0001] This invention relates to the field of pulverized coal burner technology, specifically a multi-shaft pulverized coal combustion device. Background Technology

[0002] Existing rotary kilns are used in cement or lime kilns, utilizing the heat from fuel combustion to heat the material. The rotation of the kiln causes the granular material to tumble and circulate, exposing it to flame radiation. Due to the rotation, burners (or simply burners) can only be installed at the high-temperature end of the rotary kiln. For example, Chinese invention patent CN105021028A discloses "a rotary kiln" that heats granular materials using burners installed at the discharge end. The discharge end is also the outlet for hot materials and the inlet for residual heat heating gas after discharge, so space is limited, and generally only one burner can be installed. Many rotary kilns use pulverized coal as fuel, and their burners are generally designed with an ignition channel at the center, followed by concentric pipe layers for pulverized coal channels, and then combustion air channels outwards. This type of burner has drawbacks. Because lime and cement kilns require high temperatures, the combustion flame is highly concentrated, producing a large amount of NOx pollutants. The larger the burner, the larger the high-temperature area of ​​the flame. Furthermore, if the burner is too large, beyond a certain point, it becomes difficult to mix pulverized coal and air, resulting in incomplete combustion. Therefore, using this burner method for heating results in high NOx emissions and limited production capacity.

[0003] Furthermore, NOx generation has an exponential relationship with the temperature and range of the flare's ultra-high temperature zone. Microscopically, coal particles can only burn through the penetration of oxygen molecules, requiring extremely high temperatures to ensure complete combustion. Most NOx reduction technologies aim to decrease the ultra-high temperature zone, which can lead to incomplete coal combustion and increased fuel consumption per unit output.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-axis pulverized coal combustion device, which solves the contradiction between the flame temperature and NOx emission of the concentric channel burner by distributing air into several streams and injecting it into the pulverized coal channel, thereby improving the mixing path of air and pulverized coal and overcoming the defects of the prior art such as large NOx emissions and limited heating capacity.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A multi-shaft pulverized coal combustion device includes a main structural cylinder, with a pulverized coal inlet and a combustion port at opposite ends of the main structural cylinder.

[0008] A first air pipe and a second air pipe are respectively introduced into the main structure cylinder, and the end nozzles of the first air pipe and the second air pipe are both located at the combustion port; a swirler is provided at the end of the first air pipe.

[0009] Preferably, the nozzle at the end of the second air duct has a constricted structure.

[0010] Preferably, the second air duct inside the main structure cylinder is located inside the first air duct.

[0011] Preferably, the second air duct inside the main structural cylinder is arranged concentrically with the first air duct.

[0012] Preferably, the first air ducts are all connected to the first air inlet through the first air collection box;

[0013] The second air duct is connected to the second air inlet through the second air collection box.

[0014] Preferably, an anti-wear layer is provided on the outer wall of the first air duct inside the main structure cylinder.

[0015] Preferably, a compressed air pipe is also introduced into the main structural cylinder, and the end of the compressed air pipe is closed and located inside the main structural cylinder;

[0016] Several compressed air nozzles are provided on the pipe body of the compressed air pipeline.

[0017] Preferably, a compressed air guide is also provided at the lower part of the main structure cylinder.

[0018] Compared with existing technologies, the multi-shaft pulverized coal combustion device proposed in this invention has the following advantages:

[0019] 1. The present invention proposes a multi-axis pulverized coal combustion device, which supplies oxygen for pulverized coal combustion through a first air pipe and a second air pipe. The end nozzle of the first air pipe is equipped with a cyclone separator, which is responsible for supplying oxygen to the flame near the combustion port. At the same time, the end nozzle of the second air pipe sprays oxygen at high speed to a distant location, which is responsible for supplying oxygen to the flame at a distant location. This effectively reduces the size of the flare and largely eliminates the large extremely high temperature zone of a single flare.

[0020] 2. The multi-shaft pulverized coal combustion device proposed in this invention has a compressed air pipeline installed in the main structure cylinder. The compressed air pipeline has a series of small holes on its body. The compressed air nozzle sprays compressed gas horizontally to both sides, blowing the pulverized coal deposited at the bottom of the pulverized coal channel into the air, thus preventing the pulverized coal from accumulating and blocking the pulverized coal channel.

[0021] 3. The multi-axis pulverized coal combustion device proposed in this invention has an anti-wear layer on the outer wall of the first air duct, which reduces the impact force of pulverized coal air hitting the first air duct and improves the service life of the first air duct.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of a multi-shaft pulverized coal combustion device provided in an embodiment of the present invention.

[0025] Figure 2 For along Figure 1 A schematic diagram of line AA in the middle.

[0026] Figure 3 For along Figure 1 A schematic diagram of the BB line.

[0027] The diagram is shown below:

[0028] 1. Pulverized coal inlet; 2. First air inlet; 3. Second air inlet; 4. Compressed air inlet; 5. Main structural cylinder; 6. Wear-resistant layer; 7. Cyclone separator; 8. Axial air nozzle; 9. Compressed air pipeline; 10. Compressed air nozzle; 11. Compressed air guide; 12. First air pipeline; 13. Second air pipeline; 14. First air collection box; 15. Second air collection box. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0030] like Figure 1-3 As shown, an embodiment of the present invention provides a multi-axis pulverized coal combustion device, including a main structural cylinder 5, with a pulverized coal inlet 1 and a combustion port at opposite ends of the main structural cylinder 5; a first air duct 12 and a second air duct 13 are respectively introduced into the main structural cylinder 5, with the end nozzles of the first air duct 12 and the second air duct 13 located at the combustion port; a cyclone separator 7 is provided at the end of the first air duct 12. An axial flow air nozzle 8 is provided at the end nozzle of the second air duct 13, specifically, the axial flow air nozzle 8 has a constricted design, that is, the diameter of the second air duct 131 decreases at the end nozzle to obtain a higher airflow injection velocity.

[0031] Through the above embodiments, the present invention proposes a multi-axis pulverized coal combustion device that supplies oxygen for pulverized coal combustion through a first air pipe 12 and a second air pipe 13. The end nozzle of the first air pipe 12 is equipped with a cyclone separator to supply oxygen to the flame near the combustion port, while the end nozzle of the second air pipe 13 sprays oxygen at high speed to the distant flame. This effectively reduces the size of the flare and largely eliminates the large extremely high temperature zone of a single flare, thereby reducing the generation of nitrogen oxides.

[0032] In a preferred embodiment of the above-described embodiments of the present invention, the second air duct 13 and the first air duct 12 are concentrically arranged within the main structural cylinder 5.

[0033] In the above preferred embodiment, multiple sets of air ducts are used to achieve the supply of multiple streams of air, which effectively reduces the size of the flare, further eliminates the large extremely high temperature zone of a single flare, and reduces the generation of nitrogen oxides.

[0034] In a preferred embodiment of the above-described embodiments of the present invention, the first air duct 12 is connected to the first air inlet 2 via a first gas collecting box 14; the second air duct 13 is connected to the second air inlet 3 via a second gas collecting box 15. Thus, the flow rate of gas in the first air inlet 2 and the second air inlet 3 can be simultaneously controlled by a single valve. This allows for convenient adjustment of the burner power according to the required furnace temperature and heat supply, ensuring thorough mixing of air and pulverized coal regardless of power level, and reducing excess air coefficient. In particular, it enables the direct delivery of air from distant combustion locations via a high-speed jet, resulting in higher oxygen content at the far end of the flare compared to a single-flare method with entrainment cooling, leading to more complete combustion of pulverized coal particles and effectively reducing fuel consumption.

[0035] In a preferred embodiment of the present invention, an anti-wear layer 6 is provided on the outer wall of the first air duct 12 inside the main structure cylinder 5. In the present invention, the pulverized coal inlet is located at the rear center, and a small portion of the pulverized coal air will impact the first air duct 12. The outer wall of the first air duct 12 has an anti-wear reinforcement design, which reduces the impact force of the pulverized coal air impacting the first air duct 12 and improves the service life of the first air duct 12.

[0036] In a preferred embodiment of the above-described embodiments of the present invention, a compressed air pipe 9 is further introduced into the main structural cylinder 5. The end of the compressed air pipe 9 is closed and located inside the main structural cylinder 5. Simultaneously, a plurality of compressed air nozzles 10 are provided on the pipe body of the compressed air pipe 9, and a compressed air guide 11 is also provided at the lower part of the interior of the main structural cylinder 5. The present invention provides a compressed air pipe 9 inside the main structural cylinder 5, and the compressed air pipe 9 is provided with a plurality of compressed air nozzles 10, i.e., a small hole structure. Compressed air is introduced into the compressed air pipe 9 from the compressed air inlet 4, and compressed gas with the small holes facing horizontally is sprayed into the main structural cylinder 5 through the small hole structure. This blows up the coal dust that has collided and slowed down with the first air pipe 12 or the second air pipe 13 and settled at the bottom of the main structural cylinder 5, preventing coal dust from accumulating and clogging the main structural cylinder 5.

[0037] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0038] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0039] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

Claims

1. A multi-shaft pulverized coal combustion device, characterized in that, It includes a main structural cylinder, with a pulverized coal inlet and a combustion port at each end of the main structural cylinder; Multiple sets of first air pipes and second air pipes are respectively introduced into the main structure cylinder. Each set of second air pipes is located inside the first air pipe, and the second air pipes are concentrically arranged with the first air pipes. The end nozzles of the first air pipes and the second air pipes are both located at the combustion port, and oxygen is supplied for pulverized coal combustion through the first air pipes and the second air pipes. A vortex generator is installed at the end nozzle of the first air duct to supply oxygen to the flame near the combustion port; an axial air nozzle with a constricted structure is installed at the end nozzle of the second air duct to obtain a higher airflow injection velocity to supply oxygen to the flame at a distance. A compressed air pipe is also introduced into the main structural cylinder, and the end of the compressed air pipe is closed and located inside the main structural cylinder; Several compressed air nozzles are provided on the pipe body of the compressed air pipeline; compressed air is introduced into the compressed air pipeline from the compressed air inlet and sprayed into the main structure cylinder through the compressed air nozzles. The compressed gas blows the coal dust that has been decelerated by colliding with the first air pipeline or the second air pipeline and settled at the bottom of the main structure cylinder into the air, so as to prevent the coal dust from accumulating and clogging the main structure cylinder. A compressed air guide is also provided at the bottom of the main structure cylinder.

2. The multi-shaft pulverized coal combustion device according to claim 1, characterized in that, The first air ducts are all connected to the first air inlet through the first air collection box; The second air duct is connected to the second air inlet through the second air collection box.

3. The multi-shaft pulverized coal combustion device according to claim 2, characterized in that, An anti-wear layer is provided on the outer wall of the first air duct inside the main structure cylinder.

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