Ammonia gas preheating type flow-controllable low-nitrogen ammonia-coal co-combustion burner

Abstract

The invention provides an ammonia preheating type flow-controllable low-nitrogen ammonia-coal co-combustion burner. The ammonia preheating type flow-controllable low-nitrogen ammonia-coal co-combustion burner comprises a primary air pipe, an inner secondary air pipe and an outer secondary air pipe which are sequentially arranged from inside to outside. Gas spray guns are arranged in the primary air pipe, the inner secondary air pipe and the outer secondary air pipe correspondingly, the gas spray guns arranged in the primary air pipe are used for evenly mixing gas into primary air pulverized coal flow, and the gas spray guns in the inner secondary air pipe and the gas spray guns in the outer secondary air pipe are arranged in a staggered mode. Nozzles of the gas spray gun in the inner secondary air pipe and the gas spray gun in the outer secondary air pipe are bent towards the circle center of a nozzle of the combustor so as to spray gas into the center of flame. The gas spray guns in different forms are arranged in the primary air pipe, the inner secondary air pipe and the outer secondary air pipe, and the arrangement positions are optimized, so that ammonia gas can be fully diffused and better fused with pulverized coal, the combustion process is more uniform, and the overall combustion efficiency and stability are improved.

Description

Technical Field

[0001] The present application belongs to the technical field of burners, and specifically relates to an ammonia preheating type flow-controllable low-nitrogen ammonia-coal mixed combustion burner. Background Art

[0002] Ammonia-coal co-firing technology involves mixing ammonia and coal in appropriate proportions as boiler fuel, achieving both stable combustion and low carbon emissions. By blending ammonia into coal, CO2 emissions from thermal power plants can be significantly reduced. This technology can promote the transformation and upgrading of coal-fired units while also contributing to the achievement of carbon peak and carbon neutrality goals.

[0003] During use of the relevant burners, the ammonia nozzle form, layout position and ammonia flow rate cannot be adjusted, resulting in uneven mixing of ammonia and coal powder, causing local overheating or incomplete combustion, and increasing the generation of emissions. Summary of the Invention

[0004] Therefore, the present application aims to provide an ammonia preheating flow-controllable low-nitrogen ammonia-coal mixed combustion burner to at least solve one technical problem existing in the prior art.

[0005] In order to solve the above problems, the present application provides an ammonia preheating type flow-controllable low-nitrogen ammonia-coal mixed combustion burner, which is characterized in that it includes a primary air duct, an inner secondary air duct and an outer secondary air duct arranged in sequence from the inside to the outside; gas spray guns are respectively provided in the primary air duct, the inner secondary air duct and the outer secondary air duct, and the gas spray gun arranged in the primary air duct is used to evenly mix the gas into the primary air pulverized coal flow. The gas spray gun in the inner secondary air duct and the gas spray gun in the outer secondary air duct are staggered, and the nozzles of the gas spray gun in the inner secondary air duct and the gas spray gun in the outer secondary air duct are bent toward the center of the burner nozzle to spray the gas into the center of the flame.

[0006] Optionally, the gas spray gun includes a first gas spray gun, which is disposed in the primary air duct, and the first gas spray gun is coaxially arranged with the primary air duct.

[0007] Optionally, the gas spray gun further includes a second gas spray gun and a third gas spray gun, the second gas spray gun is circumferentially arranged in the inner secondary air duct, and the third gas spray gun is circumferentially arranged in the outer secondary air duct.

[0008] Optionally, four second gas spray guns are arranged at equal intervals along the circumferential direction; and four third gas spray guns are arranged at equal intervals along the circumferential direction.

[0009] Optionally, the burner also includes a heat exchange component, which includes a heat exchanger, the inlet end of the heat exchanger is connected to the gas main pipe, and the outlet end of the heat exchanger is respectively connected to multiple gas branch pipes, each of the gas branch pipes is respectively connected to the corresponding gas spray gun, and the heat exchanger is used to heat the gas so as to pass the heated gas into the gas spray gun respectively.

[0010] Optionally, the heat exchange component includes a main pipe flow regulating component and a branch flow regulating component; the main pipe flow regulating component is arranged on the gas main pipe, and is used to regulate the gas flow in the gas main pipe; the branch flow regulating component is arranged on the gas branch pipe, and is used to regulate the gas flow in the gas branch pipe.

[0011] Optionally, the inner secondary air duct is provided with an inner secondary air swirl blade at one end close to the nozzle; the outer secondary air duct is provided with an outer secondary air swirl blade at one end close to the nozzle.

[0012] Optionally, a primary air expansion cone is provided at the nozzle of the primary air duct.

[0013] Optionally, an inner secondary air expansion cone is provided at the nozzle of the inner secondary air duct.

[0014] Optionally, an external secondary air expansion cone is provided at the nozzle of the external secondary air duct.

[0015] By means of the above technical solution, the present invention has at least the following beneficial effects:

[0016] The present application provides an ammonia preheating type flow controllable low-nitrogen ammonia-coal mixed combustion burner, which is suitable for ammonia preheating type flow controllable low-nitrogen ammonia-coal mixed combustion. By improving the nozzle form, layout position and the adjustability of ammonia flow rate, the denitrification effect of ammonia is utilized to improve the combustion efficiency of coal at the same time. After preheating, ammonia is mixed with coal powder and enters the combustion system. Through precise flow regulation and gas gun position arrangement, the uniform mixing of ammonia and coal powder is ensured, further promoting the complete combustion of coal powder, reducing the generation of unburned materials, improving combustion efficiency and reducing carbon emissions. It can not only maintain the efficiency of coal energy utilization, but also significantly reduce NO x Emissions can be reduced, complying with increasingly stringent environmental protection policy requirements, and can also improve the overall thermal efficiency and stability of the boiler. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of an ammonia preheating flow-controllable low-nitrogen ammonia-coal mixed combustion burner according to an embodiment of the present application;

[0018] Figure 2 This is a cross-sectional view of an ammonia preheating flow-controllable low-nitrogen ammonia-coal mixed combustion burner according to an embodiment of the present application.

[0019] The reference numerals indicate:

[0020] 1. Heat exchanger; 2. Hot secondary air duct; 3. Gas main pipe; 4. Main pipe flow control assembly; 5. Branch flow control assembly; 6. Ceramic sleeve; 7. Third gas spray gun; 8. First gas spray gun; 9. Third nozzle; 10. Inner secondary air swirl blade; 11. Outer secondary air swirl blade; 12. Primary air expansion cone; 13. Inner secondary air expansion cone; 14. Outer secondary air expansion cone. DETAILED DESCRIPTION

[0021] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships 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 device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0023] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0024] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0025] See also Figure 1 and Figure 2As shown, according to an embodiment of the present application, an ammonia preheating type flow-controllable low-nitrogen ammonia-coal mixed combustion burner is provided, comprising a primary air duct, an inner secondary air duct and an outer secondary air duct arranged in sequence from the inside to the outside; gas spray guns are respectively provided in the primary air duct, the inner secondary air duct and the outer secondary air duct, and the gas spray gun arranged in the primary air duct is used to evenly mix the gas into the primary air pulverized coal flow, the gas spray gun in the inner secondary air duct and the gas spray gun in the outer secondary air duct are staggered, and the nozzles of the gas spray gun in the inner secondary air duct and the gas spray gun in the outer secondary air duct are bent toward the center of the burner nozzle to spray the gas into the center of the flame.

[0026] It is suitable for low-nitrogen ammonia-coal mixed combustion with ammonia preheating and controllable flow. By improving the nozzle form, layout position and the adjustability of ammonia flow, the denitrification effect of ammonia is utilized to improve the combustion efficiency of coal. After preheating, ammonia is mixed with coal powder and enters the combustion system. Through precise flow regulation and gas nozzle position arrangement, the uniform mixing of ammonia and coal powder is ensured, which further promotes the complete combustion of coal powder, reduces the generation of unburned materials, improves combustion efficiency and reduces carbon emissions. It can not only maintain the efficiency of coal energy utilization, but also significantly reduce NO x Emissions can be reduced, complying with increasingly stringent environmental protection policy requirements, and can also improve the overall thermal efficiency and stability of the boiler.

[0027] Among them, the primary air duct, inner secondary air duct and outer secondary air duct are arranged in sequence from inside to outside, that is, the primary air duct is arranged in the center position, the inner secondary air duct is coaxially mounted on the outside of the primary air duct, and the outer secondary air duct is coaxially mounted on the outside of the inner secondary air duct.

[0028] Wherein, a gas spray gun is respectively provided in the primary air duct, the inner secondary air duct and the outer secondary air duct. The gas spray gun is used to transport gas, and the gas in this embodiment is ammonia.

[0029] When the boiler is running at low load, the overall furnace temperature is low, while the temperature required for ammonia ignition is high, resulting in poor combustion conditions. To prevent incomplete combustion, only the gas spray gun in the primary air duct is activated at this time. On the contrary, when the boiler load is high, the furnace temperature is high and the combustion conditions are improved. Therefore, the gas spray guns in the inner and outer secondary air ducts can be gradually activated according to the actual load conditions to improve combustion efficiency.

[0030] Among them, the gas spray guns in the inner secondary air duct and the gas spray guns in the outer secondary air duct are staggered, and the nozzles of the gas spray guns in the inner secondary air duct and the gas spray guns in the outer secondary air duct are bent toward the center of the burner nozzle. That is to say, the gas spray guns in the inner secondary air duct and the gas spray guns in the outer secondary air duct are alternately arranged, and at the same time, the nozzles of the gas spray guns are bent toward the center of the nozzle. The purpose of this arrangement is to enable ammonia to be effectively sprayed into the center of the flame, so that the ammonia can be fully mixed with the coal powder, ensuring a more uniform combustion process, promoting the full combustion of the coal powder, reducing the generation of unburned materials, and improving the overall combustion efficiency and stability.

[0031] The gas spray gun includes a first gas spray gun 8 , which is disposed in the primary air duct and is coaxial with the primary air duct.

[0032] The first gas lance 8 includes a first nozzle, which is designed to be a swirl type to ensure that the ammonia gas can be evenly mixed into the primary air and coal powder flow.

[0033] The first gas spray gun 8 further comprises a first gas pipe, and a first nozzle is installed at the gas outlet of the first gas pipe.

[0034] Specifically, the first air pipe is a ceramic sleeve 6 .

[0035] The gas spray gun further includes a second gas spray gun and a third gas spray gun 7 . The second gas spray gun is circumferentially arranged in the inner secondary air duct, and the third gas spray gun 7 is circumferentially arranged in the outer secondary air duct.

[0036] The second gas spray gun includes a second nozzle, which is designed to be linear and bends toward the center of the nozzle to spray ammonia directly into the center of the flame.

[0037] Specifically, the second gas spray gun further includes a second gas pipe, and a second nozzle is installed at the gas outlet of the second gas pipe.

[0038] The third gas spray gun includes a third nozzle 9 , which is designed to be linear and bends toward the center of the nozzle to spray ammonia directly into the center of the flame.

[0039] Specifically, the third gas spray gun further includes a third gas pipe, and a third nozzle 9 is installed at the gas outlet of the third gas pipe.

[0040] Four second gas spray guns are arranged at equal intervals along the circumferential direction; four third gas spray guns 7 are arranged at equal intervals along the circumferential direction.

[0041] Four second gas spray guns are arranged at equal intervals, and four third gas spray guns 7 are arranged at equal intervals. That is, the included angle between the axes of the second and third gas spray guns is 45°. This equal spacing ensures uniformity within the ammonia spray coverage area, resulting in a more balanced gas distribution across the entire area. It also effectively reduces blind spots and overlapping areas of gas spray, thereby improving overall spray efficiency and gas utilization. Furthermore, since each gas spray gun bears an equal load, it effectively improves system reliability and reduces the risk of damage to a single gas spray gun due to overload.

[0042] The burner also includes a heat exchange component, which includes a heat exchanger 1. The inlet end of the heat exchanger 1 is connected to the gas main pipe 3, and the outlet end of the heat exchanger 1 is connected to multiple gas branches respectively. Each gas branch is connected to a corresponding gas spray gun. The heat exchanger 1 is used to heat the gas so that the heated gas is passed into the gas spray gun respectively.

[0043] Among them, the heat exchanger 1 is arranged in the hot secondary air duct 2, and the ammonia is connected to the heat exchanger 1 through the gas main pipe 3. The heat of the secondary air is used to heat the ammonia from room temperature to 150°C-200°C, preheating the ammonia and increasing the temperature of the ammonia when it enters the furnace, thereby avoiding the problem of incomplete combustion or difficulty in ignition of ammonia under low temperature conditions, ensuring the full combustion of ammonia, and further ensuring the stability and efficiency of the combustion process.

[0044] Specifically, the heat exchanger 1 uses a fin-tube heat exchanger with an acoustic soot blower. In other embodiments, different types of heat exchangers 1 can be selected according to specific usage conditions.

[0045] Among them, each gas branch pipe is connected to the corresponding gas spray gun, which realizes the individual control of the gas spray gun. By switching the gas spray gun, it is convenient to control the gas spray guns at different positions.

[0046] The heat exchange assembly includes a main flow control assembly 4 and a branch flow control assembly 5. The main flow control assembly 4 is mounted on the gas main 3 and regulates the gas flow within the main gas 3. The branch flow control assembly 5 is mounted on the gas branch pipes and regulates the gas flow within the gas branch pipes. Each gas spray gun is equipped with an independent branch flow control assembly 5, which can precisely adjust the ammonia distribution amount according to changes in boiler load, achieving precise control of ammonia flow. Under different load conditions, the ammonia supply can be optimized according to actual needs, effectively controlling combustion quality and improving thermal efficiency.

[0047] Among them, the main pipe flow regulating component 4 and the branch flow regulating component 5 are both flow regulating valves.

[0048] The arrangement of nine gas lances, combined with the main pipe flow control assembly 4 and branch flow control assembly 5, addresses the problem of inflexible and imprecise ammonia flow control methods, often based on a single nozzle, which cannot precisely adjust ammonia flow distribution according to the actual boiler load. This arrangement allows precise adjustment of the ammonia flow rate based on the actual boiler load, ensuring uniform mixing of ammonia and pulverized coal, improving combustion efficiency while reducing emissions.

[0049] The inner secondary air duct is equipped with inner secondary air swirl blades 10 at one end near the nozzle, and outer secondary air swirl blades 11 at the other end near the nozzle. The rotating jets generated by inner and outer secondary air swirl blades 10, 11 help form a stable recirculation zone. This internal and external recirculation zone promotes mixing of fuel and air, enhancing combustion stability.

[0050] The nozzle of the primary air duct is provided with a primary air expansion cone 12. The nozzle of the inner secondary air duct is provided with an inner secondary air expansion cone 13. The nozzle of the outer secondary air duct is provided with an outer secondary air expansion cone 14.

[0051] Among them, the primary air expansion cone 12 is a variable diameter structure, including a first end and a second end. The diameter of the primary air expansion cone 12 gradually increases from the first end to the second end, and the primary air duct is connected to the primary air expansion cone 12 through the first end.

[0052] Among them, the inner secondary air expansion cone 13 is a variable diameter structure, including a first end and a second end. The diameter of the inner secondary air expansion cone 13 gradually increases from the first end to the second end, and the inner secondary air duct is connected to the inner secondary air expansion cone 13 through the first end.

[0053] Among them, the outer secondary air expansion cone 14 is a variable diameter structure, including a first end and a second end. The diameter of the outer secondary air expansion cone 14 gradually increases from the first end to the second end, and the outer secondary air duct is connected to the outer secondary air expansion cone 14 through the first end.

[0054] The arrangement of the primary air expansion cone 12, the inner secondary air expansion cone 13 and the outer secondary air expansion cone 14 effectively reduces eddy currents and turbulences generated by the fluid, allowing the fluid to enter the furnace more smoothly and reducing energy loss.

[0055] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0056] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application. The above are merely preferred embodiments of the present application. It should be noted that those skilled in the art may make various improvements and variations without departing from the technical principles of the present application, and such improvements and variations shall also be considered within the scope of protection of the present application.

Claims

1. An ammonia preheating type flow controllable low-nitrogen ammonia-coal mixed combustion burner, characterized in that: It comprises a primary air duct, an inner secondary air duct and an outer secondary air duct which are arranged in sequence from the inside to the outside; gas spray guns are respectively arranged in the primary air duct, the inner secondary air duct and the outer secondary air duct, the gas spray gun arranged in the primary air duct is used to evenly mix the gas into the primary air pulverized coal flow, the gas spray gun in the inner secondary air duct and the gas spray gun in the outer secondary air duct are staggered, and the nozzles of the gas spray gun in the inner secondary air duct and the gas spray gun in the outer secondary air duct are bent toward the center of the burner nozzle to spray the gas into the center of the flame.

2. The ammonia preheating flow controllable low-nitrogen ammonia-coal mixed combustion burner according to claim 1, characterized in that: The gas spray gun comprises a first gas spray gun (8), the first gas spray gun (8) is arranged in the primary air duct, and the first gas spray gun (8) is coaxially arranged with the primary air duct.

3. The ammonia preheating flow controllable low-nitrogen ammonia-coal mixed combustion burner according to claim 2 is characterized in that: The gas spray gun further comprises a second gas spray gun and a third gas spray gun (7), the second gas spray gun being arranged circumferentially in the inner secondary air duct, and the third gas spray gun (7) being arranged circumferentially in the outer secondary air duct.

4. The ammonia preheating flow controllable low-nitrogen ammonia-coal mixed combustion burner according to claim 3 is characterized in that: Four of the second gas spray guns are arranged at equal intervals along the circumferential direction; and four of the third gas spray guns (7) are arranged at equal intervals along the circumferential direction.

5. The ammonia preheating flow controllable low-nitrogen ammonia-coal mixed combustion burner according to claim 1, characterized in that: The burner further comprises a heat exchange component, the heat exchange component comprising a heat exchanger (1), the inlet end of the heat exchanger (1) being connected to a gas main pipe (3), the outlet end of the heat exchanger (1) being respectively connected to a plurality of gas branch pipes, each of the gas branch pipes being respectively connected to a corresponding gas spray gun, the heat exchanger (1) being used to heat the gas so as to pass the heated gas into the gas spray guns.

6. The ammonia preheating flow controllable low-nitrogen ammonia-coal mixed combustion burner according to claim 5, characterized in that: The heat exchange component comprises a main pipe flow regulating component (4) and a branch flow regulating component (5); the main pipe flow regulating component (4) is arranged on the gas main pipe (3) and is used to regulate the gas flow in the gas main pipe (3); the branch flow regulating component (5) is arranged on the gas branch pipe and is used to regulate the gas flow in the gas branch pipe.

7. The ammonia preheating flow controllable low-nitrogen ammonia-coal mixed combustion burner according to claim 1, characterized in that: An inner secondary air swirl blade (10) is arranged at one end of the inner secondary air duct close to the nozzle; an outer secondary air swirl blade (11) is arranged at one end of the outer secondary air duct close to the nozzle.

8. The ammonia preheating flow controllable low-nitrogen ammonia-coal mixed combustion burner according to claim 1, characterized in that: A primary air expansion cone (12) is provided at the nozzle of the primary air duct.

9. The ammonia preheating flow controllable low-nitrogen ammonia-coal mixed combustion burner according to claim 1, characterized in that: An inner secondary air expansion cone (13) is arranged at the nozzle of the inner secondary air duct.

10. The ammonia preheating flow controllable low-nitrogen ammonia-coal mixed combustion burner according to claim 1, characterized in that: An outer secondary air expansion cone (14) is arranged at the nozzle of the outer secondary air duct.

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