Combustion device and combustion system
By installing an ammonia gas vent cap at the ammonia pipeline outlet and coating it with a catalyst layer, the ammonia gas is catalytically cracked into nitrogen and hydrogen, solving the problem of insufficient ammonia combustion characteristics in circulating fluidized bed boilers and achieving more efficient combustion and lower nitrogen oxide emissions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TSINGHUA UNIVERSITY
- Filing Date
- 2025-06-16
- Publication Date
- 2026-06-05
AI Technical Summary
In existing technologies, the way ammonia enters the furnace of a circulating fluidized bed boiler is insufficient to improve combustion characteristics, resulting in the generation of more nitrogen oxides.
An ammonia gas vent cap is installed at the outlet of the ammonia gas pipeline. The surface of the ammonia gas vent cap is coated or plated with an ammonia cracking catalyst layer to catalyze the cracking of ammonia into nitrogen and hydrogen. The mixed gas enters the furnace for combustion, and the low ignition energy and high combustion temperature of hydrogen are used to improve the combustion characteristics.
It improves combustion efficiency in the furnace, reduces ammonia escape and nitrogen oxide generation, enhances ammonia combustion, simplifies the structure of the combustion device, and reduces costs.
Smart Images
Figure CN224327183U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of coal combustion, and in particular to combustion devices and combustion systems. Background Technology
[0002] The co-firing or even pure ammonia combustion in circulating fluidized bed boilers is one of the feasible ways to reduce carbon emissions in the thermal power industry, while also contributing to the absorption of renewable energy.
[0003] However, there is room for improvement in the current method of ammonia feeding into the furnace of circulating fluidized bed boilers to enhance combustion characteristics within the furnace.
[0004] Therefore, how to provide a combustion device to improve the combustion characteristics in the furnace is a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content
[0005] In view of this, the present invention provides a combustion device to improve the combustion characteristics in the furnace.
[0006] This utility model also provides a combustion system having the above-mentioned combustion device.
[0007] To achieve the above objectives, this utility model provides the following technical solution:
[0008] A combustion device includes: a furnace providing space for material combustion; a primary air chamber for generating primary air; an air distribution plate connecting the furnace and the primary air chamber; an ammonia gas pipeline located within the furnace and close to the air distribution plate; and an ammonia gas hood connecting the ammonia gas pipeline to the furnace and guiding gas entering the furnace. The surface of the ammonia gas hood has an ammonia cracking catalyst layer for cracking at least a portion of the ammonia gas passing through the ammonia gas hood into nitrogen and hydrogen.
[0009] Preferably, in the above-mentioned combustion device, the surface of the ammonia gas vent cap is coated with the ammonia cracking catalyst layer; or, the surface of the ammonia gas vent cap is plated with the ammonia cracking catalyst layer.
[0010] Preferably, in the above-mentioned combustion device, the material of the ammonia cracking catalyst layer includes iron-based or manganese-based materials.
[0011] Preferably, in the above-mentioned combustion device, the ammonia gas hood includes: a hood body and a hood cap, the hood body is connected to the ammonia gas pipeline, the hood cap is disposed at the outlet end of the hood body and is used for gas guidance; the surfaces of the hood body and the hood cap that are in contact with ammonia gas both have the ammonia cracking catalyst layer.
[0012] Preferably, in the above-mentioned combustion device, the ammonia gas pipeline is installed on the air distribution plate, and the ammonia gas pipeline is provided with a plurality of ammonia gas caps along its extension direction.
[0013] Preferably, in the above-mentioned combustion device, the ammonia gas vent cap is disposed on the side of the ammonia gas pipeline away from the air distribution plate, and the ammonia gas vent cap extends along the height direction of the furnace.
[0014] Preferably, the combustion device further includes: air nozzles, which are disposed on the side wall of the ammonia pipeline parallel to the air distribution plate. The air nozzles are disposed on both sides of the ammonia pipeline parallel to the air distribution plate, and the air nozzles are symmetrically arranged with respect to the extension direction of the ammonia pipeline.
[0015] Preferably, in the above-mentioned combustion device, a plurality of ammonia pipes are arranged side by side on the air distribution plate, and the air nozzles of adjacent ammonia pipes are staggered along the arrangement direction of the ammonia pipes.
[0016] Preferably, in the above-mentioned combustion device, the air distribution plate is provided with a primary air cap for primary air circulation between adjacent ammonia pipes; the outlet of the ammonia air cap is staggered from the primary air cap along the arrangement direction of the ammonia pipes.
[0017] A combustion system includes a combustion device, wherein the combustion device is any of the combustion devices described above.
[0018] This invention discloses a combustion device. An ammonia gas vent cap is installed at the outlet of the ammonia gas channel that introduces ammonia into the furnace. The surface of the ammonia gas vent cap has an ammonia cracking catalyst layer. The ammonia cracking catalyst can crack a portion of the passing ammonia gas to obtain nitrogen and hydrogen. During the flow of ammonia through the ammonia gas vent cap, some ammonia is cracked to obtain nitrogen and hydrogen. The cracked nitrogen and hydrogen mix with uncracked ammonia gas to form a mixed gas that enters the furnace. The mixed gas then undergoes primary mixing and combustion within the furnace. Because hydrogen has a lower minimum ignition energy and a higher combustion temperature than ammonia, it is easier to burn. Furthermore, hydrogen has a faster flame propagation speed than ammonia. Therefore, it can improve the combustion characteristics within the furnace, enhance the combustion effect of ammonia, thereby reducing ammonia escape and allowing more ammonia to react with nitrogen oxides, thus inhibiting the formation of nitrogen oxides. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0020] Figure 1 This is a schematic diagram of the combustion device disclosed in an embodiment of the present utility model;
[0021] Figure 2 This is a partial enlarged view of the combustion device disclosed in an embodiment of this utility model;
[0022] Figure 3 This is a front view of the ammonia vent cap disclosed in this embodiment of the utility model;
[0023] Figure 4 This is a top view of the connection relationship of the ammonia gas vent cap of the combustion system disclosed in the embodiment of this utility model in the first position;
[0024] Figure 5 for Figure 4 Sectional view of AA;
[0025] Figure 6 This is a top view of the connection relationship of the ammonia gas vent cap of the combustion system disclosed in the embodiment of this utility model when it is in the second position;
[0026] Figure 7 for Figure 6 A sectional view of CC.
[0027] in:
[0028] 101-Furnace chamber, 102-Primary air chamber, 103-Air distribution plate, 104-Ammonia gas pipeline;
[0029] 1031-Primary air cap, 1041-Ammonia air cap, 10411-Air cap body, 10412-Ammonia cracking catalyst layer, 104111-Cap body, 104112-Cap cover, 1042-Air nozzle;
[0030] 200 - Gas collection pipe, 300 - Hydraulic tank, 400 - Vaporization buffer tank, 500 - Control valve. Detailed Implementation
[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0032] Hereinafter, 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.
[0033] A fluidized bed is a fluid-solid contact state in which a large number of solid particles are suspended in a moving fluid, giving the particles some of the apparent characteristics of the fluid. In this state, the solid particles are carried out of the bed by the airflow, and then separated by a separator and recycled back into the bed, forming a circulating fluidized bed.
[0034] Circulating fluidized bed (CFB) boilers utilize fluidized bed combustion, representing a highly industrialized clean coal combustion technology. CFB boilers offer advantages such as high combustion efficiency, low pollutant emissions, strong variable load capacity, and a wide range of fuel adaptability.
[0035] Circulating fluidized bed (CFB) boilers produce a large amount of nitrogen oxides (NOx) during combustion. To reduce NOx emissions and thus decrease harmful gas emissions, ammonia is typically introduced into the CFB boiler. Specifically, ammonia can use selective non-catalytic reduction (SNCR) technology to reduce NOx into nitrogen and water, thereby reducing harmful gas emissions and protecting the environment. Furthermore, ammonia in CFB boilers can promote denitrification reactions and improve the boiler's energy efficiency.
[0036] However, there is room for improvement in the current method of ammonia feeding into the furnace of circulating fluidized bed boilers to enhance combustion characteristics within the furnace.
[0037] Based on the above objectives, this application discloses a combustion device, including but not limited to a circulating fluidized bed. The combustion device has a wind cap for guiding the flow of ammonia gas, wherein the surface of the wind cap has an ammonia cracking catalyst, which can catalytically crack at least a portion of the ammonia, thereby enabling the ammonia to have a longer residence time, resulting in better mixing of ammonia and air, and thus improving the ammonia combustion rate.
[0038] The following combination Figures 1 to 3 The combustion apparatus disclosed in the embodiments of this application will be described.
[0039] like Figure 1 and Figure 2 As shown, the combustion device disclosed in this application embodiment includes: a furnace 101, a primary air chamber 102, an air distribution plate 103, and an ammonia gas pipeline 104.
[0040] The furnace 101 is divided into a dense phase zone and a dilute phase zone according to the concentration of the material. The dense phase zone is lower than the dilute phase zone along the height direction of the combustion device.
[0041] The furnace 101 is higher than the primary air chamber 102 along the height direction of the combustion device, which can be understood as: the primary air chamber 102 is located below the furnace 101.
[0042] The primary air chamber 102 is connected to the furnace 101 via an air distribution plate 103. Optionally, a primary air cap 1031 is provided on the air distribution plate 103, allowing the primary air in the primary air chamber 102 to enter the furnace 101 through the primary air cap 1031. By providing the primary air cap 1031, the flow direction of the primary air passing through the air distribution plate 103 can be guided, allowing the primary air to enter the furnace 101 from the side of the primary air cap 1031, preventing the primary air from blowing directly into the furnace 101, and ensuring the uniformity of the primary air distribution entering the furnace 101.
[0043] The shape, size and structure of the primary air cap 1031 can be set according to different needs. As long as the structure of the primary air cap 1031 can guide the flow direction of the primary air entering the furnace 101, it is within the protection range.
[0044] An ammonia gas pipe 104 is provided on the side of the air distribution plate 103 near the furnace 101, through which ammonia gas can be supplied into the furnace 101. In other optional embodiments, the ammonia gas pipe 104 may also be located in the dense phase zone of the furnace 101, in the middle of the furnace 101 along the height direction, or in the upper part of the furnace 101 along the height direction.
[0045] It should be noted that the ammonia pipeline 104 is located on the side of the air distribution plate 103 near the furnace 101, which can supply ammonia to the furnace 101 from the bottom, thereby enhancing the mixing of ammonia and primary air, accelerating the combustion of ammonia, and thus making the bottom temperature of the furnace 101 higher, and enabling the synergistic removal of CO and NO.
[0046] In an optional embodiment, the ammonia gas pipe 104 is fixed to the upper surface of the air distribution plate 103 along the height direction of the furnace 101. The extension direction of the ammonia gas pipe 104 is parallel to the air distribution plate 103. The shape and size of the ammonia gas pipe 104 can be set according to different needs, and the extension directions of adjacent ammonia gas pipes 104 include, but are not limited to, parallel.
[0047] Multiple primary air caps 1031 are arranged on the air distribution plate 103 along the extension direction of the ammonia pipeline 104. The primary air caps 1031 are not limited to those that are evenly distributed. The air distribution plate 103 includes, but is not limited to, multiple ammonia pipelines 104, and primary air caps 1031 are arranged between adjacent ammonia pipelines 104.
[0048] In this embodiment of the application, the ammonia pipeline 104 has an ammonia vent cap 1041 that communicates with the furnace 101. The ammonia pipeline 104 is connected to the furnace 101 through the ammonia vent cap 1041, so that the ammonia in the ammonia pipeline 104 enters the furnace 101 through the ammonia vent cap 1041.
[0049] like Figure 3 As shown, the ammonia vent cap 1041 in this embodiment of the application includes a vent cap body 10411 and an ammonia cracking catalyst layer 10412.
[0050] The ammonia gas pipeline 104 is connected to the vent cap body 10411, and the ammonia gas pipeline 104 is connected to the furnace 101 through the vent cap body 10411, so that the ammonia gas in the ammonia gas pipeline 104 enters the furnace 101 through the vent cap body 10411. Optionally, the vent cap body 104111 includes a cap body 104111 and a cap cover 104112, wherein the cap body 104111 is a pipeline structure, and the cap cover 104112 is disposed at the outlet end of the cap body 104111 and is used to guide the gas.
[0051] The surface of the wind cap body 10411 has an ammonia cracking catalyst layer 10412. During the process of ammonia gas passing through the wind cap body 10411 in the ammonia gas pipeline 104, some of the ammonia gas can react with the ammonia cracking catalyst layer 10412 and be cracked into nitrogen and hydrogen.
[0052] Optionally, both the surface of the cap 104111 and the surface of the cap 104112 that come into contact with ammonia gas have an ammonia cracking catalyst layer 10412. In some embodiments, the inner wall of the cap 104111 for ammonia gas flow has an ammonia cracking catalyst layer 10412, and the surface of the cap 104112 opposite to the outlet of the cap 104111 and for guiding the ammonia gas also have an ammonia cracking catalyst layer 10412.
[0053] The ammonia gas vent 1041 disclosed in this application has an ammonia cracking catalyst layer 10412. The ammonia cracking catalyst layer 10412 can crack a portion of the passing ammonia gas to obtain nitrogen and hydrogen. The cracked nitrogen and hydrogen are mixed with uncracked ammonia gas to form a mixed gas that enters the furnace 101. The mixed gas is then mixed and burned in the furnace 101. Because hydrogen has a lower minimum ignition energy and a higher combustion temperature than ammonia, it is easier to burn than ammonia. In addition, hydrogen has a faster flame propagation speed than ammonia. Therefore, it can improve the combustion characteristics in the furnace 101, enhance the combustion effect of ammonia, thereby reducing ammonia escape and allowing more ammonia to react with nitrogen oxides, thus achieving the purpose of suppressing the formation of nitrogen oxides.
[0054] In some embodiments, an ammonia cracking catalyst layer 10412 may be coated onto the surface of the wind cap body 10411, or the surface of the wind cap body 10411 may be plated with an ammonia cracking catalyst layer 10412. The methods for forming the ammonia cracking catalyst layer 10412 on the wind cap body 10411 include, but are not limited to, the methods described above. By using coating or plating, it is not necessary to install an additional catalytic device inside the furnace 101, which simplifies the structure of the combustion device and reduces its cost.
[0055] Optionally, the material of the ammonia cracking catalyst layer 10412 includes, but is not limited to, iron-based or manganese-based doped materials. In some embodiments, the thickness of the ammonia cracking catalyst layer 10412 on the surface of the air cap body 10411 includes, but is not limited to, 10 μm. In the catalytic reaction of ammonia, the ammonia cracking catalyst layer 10412 of this application embodiment achieves efficient ammonia cracking under the heat of the air distribution plate 103, reducing the need for additional energy supply to the combustion device and further reducing the cost of the combustion device.
[0056] Combination Figure 4 and Figure 5As shown, the ammonia gas vent 1041 is located at the end of the ammonia gas pipeline 104 away from the air distribution plate 103, which can be understood as the ammonia gas vent 1041 extending along the height direction. Specifically, the vent body 104111 extends along the height direction, and the cap 104112 is arranged along the height direction with the vent body 104111. The ammonia gas vent 1041 can guide the flow direction of the gas entering the furnace 101 (including nitrogen and hydrogen obtained from cracking and uncracked ammonia), so that the gas is blown out from the circumference of the cap 104112 of the vent body 10411 towards the air distribution plate 103, and under the obstruction of the outer wall of the ammonia gas pipeline 104, the gas flows away from the air distribution plate 103, thus completing the uniform diffusion of the gas entering the furnace 101 and preventing direct blowing of the gas into the material inside the furnace 101. In addition, the ammonia gas hood 1041 can slow down the flow rate of the gas and prolong the time the gas spends at the air distribution plate 103 in the furnace 101, which can ensure that the gas is fully mixed with the primary air, thereby enhancing ammonia combustion.
[0057] In some embodiments, a plurality of ammonia gas vent caps 1041 are provided along the extending direction of the ammonia gas pipeline 104, and the ammonia gas vent caps 1041 are, but not limited to, evenly distributed along the extending direction. In the embodiments of this application, the ammonia gas vent caps 1041 extend along the height direction, and the cap 104112 is located at the end of the cap body 104111 away from the air distribution plate 103, which can prevent the outlets of adjacent ammonia gas vent caps 1041 of the ammonia gas pipeline 104 from being opposite each other and affecting the entry of ammonia gas into the furnace 101.
[0058] Combination Figure 6 and Figure 7 As shown, an ammonia vent cap 1041 is provided at the end of the ammonia pipeline 104 away from the air distribution plate 103, and an air nozzle 1042 is provided along the side wall of the ammonia pipeline 104 parallel to the air distribution plate 103.
[0059] Among them, the ammonia gas vent cap 1041 at the end of the ammonia gas pipeline 104 away from the air distribution plate 103 is as follows: Figure 3 and Figure 4 The ammonia vent cap 1041 shown is shown.
[0060] Air nozzles 1042 are disposed on the side wall of the ammonia duct 104 parallel to the air distribution plate 103, and the air nozzles 1042 are arranged symmetrically with respect to the extension direction of the ammonia duct 104. Optionally, the air nozzles 1042 extend parallel to the air distribution plate 103 or are arranged inclined to the air distribution plate 103.
[0061] By setting the air nozzle 1042, the air intake efficiency of the furnace 101 can be increased.
[0062] In some embodiments, the air distribution plate 103 has multiple ammonia pipes 104 arranged side by side. Optionally, the ammonia pipes 104 are radially distributed parallel to the air distribution plate 103. The extension direction of the nozzles 1042 is parallel to or relatively inclined to the surface of the air distribution plate 103. Optionally, the nozzles 1042 of adjacent ammonia pipes 104 are staggered along the arrangement direction of the ammonia pipes 104, which can be understood as the outlets of the nozzles 1042 of adjacent ammonia pipes 104 not facing each other.
[0063] The above arrangement can avoid mutual interference between the nozzles 1042 of adjacent ammonia gas pipelines 104, further improve the uniformity of the gas entering the furnace 101, and facilitate the mixing of gas with primary air.
[0064] In some embodiments, the nozzle 1042 and the primary air cap 1031 on the air distribution plate 103 are arranged opposite or not opposite each other along the arrangement direction of the ammonia pipeline 104. Optionally, the nozzle 1042 and the primary air cap 1031 of the ammonia pipeline 104 are arranged opposite each other, which can improve the mixing of gas and primary air; alternatively, the nozzle 1042 and the primary air cap 1031 of the ammonia pipeline 104 are arranged in a staggered manner, which can avoid the gas and primary air from affecting each other and causing the primary air and gas to be unable to be discharged smoothly.
[0065] In addition, this application also discloses a combustion system, including a combustion device, a gas collection pipe 200, a hydraulic tank 300, a vaporization buffer tank 400, and a control valve 500. The combustion device is the same as disclosed in the above embodiments. Therefore, the combustion system with this combustion device also has all the above-mentioned technical effects, which will not be described in detail here.
[0066] The output end of the hydraulic tank 300 is connected to the input end of the vaporization buffer tank 400. The output end of the vaporization buffer tank 400 is connected to the input end of the gas collecting pipe 200 through the control valve 500. The output port of the gas collecting pipe 200 is connected to the ammonia pipeline 104.
[0067] The flow rate of ammonia gas from the vaporization buffer tank 400 to the gas collection pipe 200 can be controlled by the control valve 500.
[0068] The gas collecting pipe 200 includes, but is not limited to, two, and the output end of the gasification buffer tank 400 is simultaneously connected to multiple gas collecting pipes 200. In some embodiments, the gas collecting pipe 200 is disposed on the outer wall of the combustion device and communicates with the ammonia pipeline 104 inside the combustion device. Optionally, one gas collecting pipe 200 is connected to each end of the ammonia pipeline 104 along its extension direction.
[0069] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0070] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A combustion device, characterized in that, include: A furnace (101) provides space for the combustion of materials; A primary air chamber (102) is used to generate primary air; Air distribution plate (103), the furnace (101) and the primary air chamber (102) are connected through the air distribution plate (103); Ammonia gas pipeline (104), the ammonia gas pipeline (104) is located inside the furnace (101) and close to the air distribution plate (103); An ammonia gas vent cap (1041) is provided to connect the ammonia gas pipeline (104) to the furnace (101) and to guide the gas entering the furnace (101). The surface of the ammonia gas vent cap (1041) has an ammonia cracking catalyst layer (10412) for cracking at least a portion of the ammonia gas passing through the ammonia gas vent cap (1041) into nitrogen and hydrogen.
2. The combustion device according to claim 1, characterized in that, The surface of the ammonia gas vent (1041) is coated with the ammonia cracking catalyst layer (10412); Alternatively, the surface of the ammonia gas vent cap (1041) may be coated with the ammonia cracking catalyst layer (10412).
3. The combustion device according to claim 1, characterized in that, The materials of the ammonia cracking catalyst layer (10412) include iron-based or manganese-based materials.
4. The combustion device according to claim 1, characterized in that, The ammonia gas vent cap (1041) includes: The cap body (104111) and the cap cover (104112) are provided. The cap body (104111) is connected to the ammonia pipeline (104). The cap cover (104112) is provided at the outlet end of the cap body (104111) and is used for gas guidance. The surface of the cap (104111) that comes into contact with ammonia and the surface of the cap (104112) that comes into contact with ammonia both have the ammonia cracking catalyst layer (10412).
5. The combustion device according to any one of claims 1 to 4, characterized in that, The ammonia pipe (104) is installed on the air distribution plate (103), and the ammonia pipe (104) is provided with a plurality of ammonia air caps (1041) along the extension direction.
6. The combustion device according to claim 5, characterized in that, The ammonia gas vent cap (1041) is located on the side of the ammonia gas pipeline (104) away from the air distribution plate (103), and the ammonia gas vent cap (1041) extends along the height direction of the furnace (101).
7. The combustion device according to claim 6, characterized in that, Also includes: Air nozzle (1042) is provided on the side wall of the ammonia pipeline (104) parallel to the air distribution plate (103). Air nozzles (1042) are provided on both sides of the ammonia pipeline (104) parallel to the air distribution plate (103). The air nozzles (1042) are symmetrically arranged with respect to the extension direction of the ammonia pipeline (104).
8. The combustion device according to claim 7, characterized in that, Multiple ammonia pipes (104) are arranged side by side on the air distribution plate (103), and the air nozzles (1042) of adjacent ammonia pipes (104) are staggered along the arrangement direction of the ammonia pipes (104).
9. The combustion device according to claim 8, characterized in that, The air distribution plate (103) is provided with a primary air cap (1031) for the flow of primary air between adjacent ammonia gas pipes (104); The outlet of the ammonia gas vent cap (1041) is staggered from the primary vent cap (1031) along the arrangement direction of the ammonia gas pipeline (104).
10. A combustion system, comprising a combustion device, characterized in that, The combustion device is the combustion device as described in any one of claims 1 to 9.