Pyrolysis combustor and combustion system

Abstract

The invention discloses a pyrolysis combustor and a combustion system.The pyrolysis combustor comprises a pyrolysis combustion body, the pyrolysis combustion body is provided with a combustion cavity, a first flue gas outlet and a second flue gas outlet, the first flue gas outlet and the second flue gas outlet communicate with the combustion cavity, and the second flue gas outlet is lower than the first flue gas outlet; a first ammonia gas port, a second ammonia gas port and a wind powder gas port which communicate with the combustion cavity are formed in the pyrolysis combustion body, and a pyrolysis gas outlet communicating with the combustion cavity is formed in the top of the pyrolysis combustion body. According to the pyrolysis burner, internal circulation of flue gas is achieved, in-situ premixing of ammonia and coal / biomass pyrolysis products is achieved, the combustion stability and burn-off rate of ammonia are remarkably improved, concentrated heat release is avoided, generation of nitric oxide precursors is reduced, the pyrolysis gas outlet is formed in the top of the pyrolysis combustion main body, and the combustion efficiency is improved. High-activity pyrolysis gas can be effectively guided out and recycled, the fuel utilization rate is increased, and large-proportion ammonia blending combustion is supported.

Description

Technical Field

[0001] This invention relates to the field of coal combustion control technology, and in particular to a pyrolysis burner and combustion system. Background Technology

[0002] Related technologies indicate that, against the backdrop of global efforts to address climate change, the high carbon emissions from the combustion of traditional fossil fuels urgently need to be addressed. Green ammonia, as a zero-carbon fuel that overcomes the bottlenecks in hydrogen energy storage and transportation, provides a new pathway for the large-scale consumption and cross-regional allocation of clean energy sources such as wind and solar power. The carbon released from biomass combustion originates from atmospheric carbon absorbed through photosynthesis, with net emissions approaching zero throughout its entire life cycle, enabling the conversion of waste into energy and achieving both carbon reduction and increased revenue. The co-firing of pulverized coal with multiple zero-carbon fuels, as a key pathway for the low-carbon transformation of coal-fired power, faces core challenges such as combustion stability, thermal efficiency, and synergistic control of pollutants, necessitating the development of efficient, low-emission combustion technologies for multiple fuels suitable for wide-load operation. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a pyrolysis burner that enables in-situ premixing of ammonia with coal / biomass pyrolysis products, significantly improving the combustion stability and burnout rate of ammonia, supporting high-proportion ammonia blending, promoting the application of low-carbon / zero-carbon fuels, and contributing to the decarbonization of energy systems.

[0004] The present invention also proposes a combustion system having the above-mentioned pyrolysis burner.

[0005] According to a first aspect of the present invention, a pyrolysis burner includes: a pyrolysis combustion body, the pyrolysis combustion body having a combustion chamber and a first flue gas outlet and a second flue gas outlet communicating with the combustion chamber, the second flue gas outlet being arranged lower than the first flue gas outlet, the pyrolysis combustion body having a first ammonia inlet, a second ammonia inlet and a pulverized air inlet communicating with the combustion chamber, the first ammonia inlet, the second ammonia inlet and the pulverized air inlet being arranged adjacent to each other in the vertical direction, and a pyrolysis gas outlet communicating with the combustion chamber being formed at the top of the pyrolysis combustion body.

[0006] According to the pyrolysis burner of the present invention, internal flue gas circulation is achieved by arranging a first flue gas outlet and a second flue gas outlet in the vertical direction. In-situ premixing of ammonia with coal / biomass pyrolysis products is achieved by arranging ammonia inlet and primary air / coal pulverized gas inlet adjacent to each other in the vertical direction, which significantly improves the combustion stability and burnout rate of ammonia. Furthermore, the setting of the first and second ammonia inlets enables staged supply and combustion of ammonia, avoiding concentrated heat release and reducing the generation of nitrogen oxide precursors. By setting the pyrolysis gas outlet at the top of the pyrolysis combustion body, highly active pyrolysis gas can be effectively exported and reused, improving fuel utilization rate. At the same time, it avoids coking caused by pyrolysis gas retention, supports high-proportion ammonia blending, promotes the application of low-carbon / zero-carbon fuels, and helps decarbonize the energy system.

[0007] In some embodiments, an ignition port is formed on the pyrolysis combustion body, and an ignition element is provided at the position of the ignition port.

[0008] In some embodiments, the pyrolysis burner further includes: a first ammonia gas channel, a second ammonia gas channel, and a coal-air gas channel, wherein the first ammonia gas channel is connected to the first ammonia gas port, the second ammonia gas channel is connected to the second ammonia gas port, and the coal-air gas channel is connected to the coal-air gas port.

[0009] In some embodiments, the first ammonia channel, the second ammonia channel, and the air-powder channel all extend along the circumferential direction of the pyrolysis combustion body.

[0010] In some embodiments, the pyrolysis burner further includes: a first flue gas passage and a second flue gas passage, wherein the first flue gas passage is connected to the first flue gas outlet and the second flue gas passage is connected to the second flue gas outlet.

[0011] In some embodiments, both the first flue gas passage and the second flue gas passage extend along the circumferential direction of the pyrolysis combustion body.

[0012] In some embodiments, the combustion chamber has a first part, a second part, and a third part, the cross-sectional area of ​​the first part gradually increases in a downward direction, the second part is formed in a cylindrical shape, and the side of the third part opposite to the second part is formed in an arc shape convex toward the side opposite to the second part.

[0013] The combustion system according to a second aspect of the invention includes a boiler and a pyrolysis burner according to a first aspect of the invention.

[0014] According to the combustion system of the present invention, by setting up the combustion system of the first aspect described above, the same technical effects are achieved. That is, by arranging the first flue gas outlet and the second flue gas outlet in the vertical direction, internal circulation of flue gas is realized. By arranging the ammonia inlet and the air-coal inlet adjacent to each other in the vertical direction, in-situ premixing of ammonia with coal / biomass pyrolysis products is realized, which significantly improves the combustion stability and burnout rate of ammonia. Furthermore, setting up the first ammonia inlet and the second ammonia inlet enables staged supply and combustion of ammonia, avoiding concentrated heat release and reducing the generation of nitrogen oxide precursors. By setting the pyrolysis gas outlet at the top of the pyrolysis combustion body, highly active pyrolysis gas can be effectively exported and reused, improving fuel utilization. At the same time, it avoids the risk of coking or explosion caused by pyrolysis gas retention, supports high-proportion ammonia blending, promotes the application of low-carbon / zero-carbon fuels, and helps decarbonize the energy system.

[0015] In some embodiments, the boiler has a reburning zone and a main combustion zone, and the pyrolysis gas outlet of the pyrolysis burner is connected to both the reburning zone and the main combustion zone.

[0016] In some embodiments, the second ammonia inlet, the first flue gas outlet, and the second flue gas outlet of the pyrolysis burner are all connected to the main combustion zone.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a pyrolysis burner according to a first aspect embodiment of the present invention; Figure 2 yes Figure 1 A schematic diagram of the internal structure of the pyrolysis burner shown in the figure; Figure 3 This is a schematic diagram of a combustion system according to a second aspect embodiment of the present invention.

[0019] Figure label: 100. Pyrolysis burner; 1. Pyrolysis combustion body; 11. Combustion chamber; 111. First part; 112. Second part; 113. Third part; 12. First flue gas outlet; 13. Second flue gas outlet; 14. First ammonia inlet; 15. Second ammonia inlet; 16. Air-coal gas inlet; 17. Pyrolysis gas outlet; 18. Ignition port; 2. Ignition element; 3. First ammonia gas passage; 4. Second ammonia gas passage; 5. Air-coal gas passage; 6. First flue gas passage; 7. Second flue gas passage; 200. Boiler; 201. Reburning zone; 202. Main combustion zone; 1000. Combustion system. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] The following is for reference. Figure 1 and Figure 2 A pyrolysis burner 100 according to an embodiment of the first aspect of the present invention is described.

[0022] like Figure 1 and Figure 2 As shown, the pyrolysis burner 100 according to a first aspect embodiment of the present invention includes: a pyrolysis combustion body 1.

[0023] Specifically, the pyrolysis combustion body 1 has a combustion chamber 11 and a first flue gas outlet 12 and a second flue gas outlet 13 connected to the combustion chamber 11. The second flue gas outlet 13 is arranged lower than the first flue gas outlet 12. The pyrolysis combustion body 1 has a first ammonia gas inlet 14, a second ammonia gas inlet 15 and a pulverized air gas inlet 16 connected to the combustion chamber 11. The first ammonia gas inlet 14, the second ammonia gas inlet 15 and the pulverized air gas inlet 16 are arranged adjacent to each other in the vertical direction. The top of the pyrolysis combustion body 1 has a pyrolysis gas outlet 17 connected to the combustion chamber 11. It is understood that the pyrolysis combustion body 1 has a combustion chamber 11, a first flue gas outlet 12, a second flue gas outlet 13, a first ammonia gas outlet 14, a second ammonia gas outlet 15, a pulverized air gas outlet 16, and a pyrolysis gas outlet. The first flue gas outlet 12, the second flue gas outlet 13, the first ammonia gas outlet 14, the second ammonia gas outlet 15, the pulverized air gas outlet 16, and the pyrolysis gas outlet are all connected to the combustion chamber 11. The first ammonia gas outlet 14, the second ammonia gas outlet 15, and the pulverized air gas outlet 16 are all arranged on one side of the pyrolysis combustion body 1 in the radial direction and are arranged opposite to the second flue gas outlet 13 in the radial direction of the pyrolysis combustion body 1.

[0024] The second flue gas outlet 13 is arranged lower than the first flue gas outlet 12, which is located at a higher position. That is, the first flue gas outlet 12 and the second flue gas outlet 13 are arranged vertically. The first flue gas outlet 12 is mainly used to discharge into the main combustion zone 202 and / or the recombustion zone 201 for combustion. The second flue gas outlet 13 is located at a lower position, which can lead out medium and low temperature flue gas. In this way, it flows back to the combustion system 1000 as a heat carrier to increase the furnace temperature, or it can be used to preheat fuel and air, improve the system thermal efficiency, realize the staged discharge of flue gas, optimize the temperature field and flow distribution in the furnace, and the high and low dual outlet design helps to form flue gas recirculation and temperature gradient control, suppress local high temperature, and reduce the generation of nitrogen oxides.

[0025] The first ammonia inlet 14, the second ammonia inlet 15, and the air-powder inlet 16 are arranged adjacent to each other in the vertical direction. This allows solid fuel to enter and be heated to start pyrolysis, generating pyrolysis gas (hydrogen, carbon monoxide, methane, etc.). Ammonia is introduced in two stages and premixed with the pyrolysis gas and volatiles for co-combustion. The high activity of the pyrolysis gas promotes the ignition and combustion of ammonia. In this way, the staged supply of ammonia avoids the surge of nitrogen oxides in the high-temperature zone caused by concentrated combustion, and realizes the staged combustion of ammonia.

[0026] According to the pyrolysis burner 100 of the present invention, the internal circulation of flue gas is achieved by arranging the first flue gas outlet 12 and the second flue gas outlet 13 in the vertical direction. The in-situ premixing of ammonia with coal / biomass pyrolysis products is achieved by arranging the ammonia inlet and the air-coal inlet 16 adjacent to each other in the vertical direction, which significantly improves the combustion stability and burnout rate of ammonia. Furthermore, the setting of the first ammonia inlet 14 and the second ammonia inlet 15 realizes the staged supply and combustion of ammonia, avoids concentrated heat release, and reduces the generation of nitrogen oxide precursors. By setting the pyrolysis gas outlet 17 at the top of the pyrolysis combustion body 1, the highly active pyrolysis gas can be effectively exported and reused, improving fuel utilization rate. At the same time, it avoids coking caused by pyrolysis gas retention, supports high-proportion ammonia blending, promotes the application of low-carbon / zero-carbon fuels, and helps decarbonize the energy system.

[0027] In some embodiments of the present invention, such as Figure 1 and Figure 2 As shown, an ignition port 18 is formed on the pyrolysis combustion body 1, and an ignition element 2 is installed at the position of the ignition port 18. It can be understood that when the ignition element 2 is activated, it generates a spark or a high-temperature flame. Simultaneously, the pulverized coal gas and ammonia gas begin to enter the combustion chamber 11. The ignition element 2 first ignites the flammable substances to form a stable flame, which gradually ignites the subsequent pulverized coal, biomass coke, and pyrolysis gas, achieving full fuel combustion. Therefore, under low load or fuel fluctuations, the ignition element 2 can maintain a "perpetual flame" or operate intermittently as a stable combustion source, preventing the flame from extinguishing. For situations with a high ammonia proportion (where ammonia combustion stability is poor), the ignition element 2 continuously provides a heat source, significantly improving combustion stability.

[0028] In some embodiments of the present invention, such as Figure 1 and Figure 2 As shown, the pyrolysis burner 100 further includes: a first ammonia gas channel 3, a second ammonia gas channel 4, and a coal-air gas channel 5. The first ammonia gas channel 3 is connected to the first ammonia gas port 14, the second ammonia gas channel 4 is connected to the second ammonia gas port 15, and the coal-air gas channel 5 is connected to the coal-air gas port 16. Thus, by setting the first ammonia gas channel 3 to deliver ammonia gas into the combustion chamber 11, and by setting the second ammonia gas channel 4, a graded supply of ammonia gas is achieved. This allows for adjustment of the combustion temperature distribution, reduces the generation of nitrogen oxides caused by concentrated combustion in the high-temperature zone, improves the ammonia burnout rate, and reduces the escape of unburned ammonia.

[0029] In some embodiments of the present invention, the first ammonia channel 3, the second ammonia channel 4, and the air-powder channel 5 all extend along the circumferential direction of the pyrolysis combustion body 1. Thus, arranged along the circumferential tangential direction of the inner wall or internal structure of the pyrolysis combustion body 1, an annular or spiral air intake path is formed, thereby creating a stable swirling reflux zone, preventing flameout or flameout, and improving combustion stability. The circumferentially introduced ammonia and air-powder pyrolysis gas are fully stirred in the rotating flow field, prolonging the residence time in the combustion chamber 11, achieving rapid premixing of ammonia with active components such as hydrogen, carbon monoxide, and methane, promoting co-combustion reaction, and improving the burnout rate of pulverized coal, biomass, and ammonia.

[0030] In some embodiments of the present invention, the pyrolysis burner 100 further includes a first flue gas passage 6 and a second flue gas passage 7, wherein the first flue gas passage 6 is connected to the first flue gas outlet 12, and the second flue gas passage 7 is connected to the second flue gas outlet 13. Thus, the first flue gas passage 6 and the second flue gas passage 7 are provided to distinguish the flue gas from the high-temperature main combustion zone 202 and the medium- and low-temperature reaction zone, achieving staged flue gas extraction and improving system thermal efficiency. The hot flue gas extracted from the second flue gas passage 7 can be used to preheat pulverized coal or ammonia, increasing the fuel temperature entering the furnace and improving ignition performance and combustion efficiency.

[0031] In some embodiments of the present invention, such as Figure 1 and Figure 2 As shown, both the first flue gas passage 6 and the second flue gas passage 7 extend along the circumferential direction of the pyrolysis combustion body 1. Thus, the circumferentially extending first flue gas passage 6 and second flue gas passage 7 form an annular gas collection structure in the circumferential direction, which can uniformly collect flue gas from all sides of the combustion chamber 11, avoiding flow field deflection or vortex instability caused by uneven local exhaust. In addition, it works in conjunction with the circumferentially fed fuel passage (such as air-coal or ammonia passage) to form a matched flow field of "intake swirl - exhaust circulation", maintaining a stable rotating flame structure in the combustion chamber 11 and preventing flameout.

[0032] In some embodiments of the present invention, such as Figure 1 and Figure 2 As shown, the combustion chamber 11 has a first part 111, a second part 112, and a third part 113. The cross-sectional area of ​​the first part 111 gradually increases from top to bottom. The second part 112 is cylindrical. The side of the third part 113 facing away from the second part 112 is formed as an arc protruding away from the second part 112. It can be understood that the first part 111 is used to guide the high-temperature flue gas to rise and diffuse smoothly, reducing flow resistance, which is conducive to uniform gas collection and avoids local high-speed scouring. The second part 112 is the core combustion zone, which can ensure that the combustion process is controllable and efficient, and avoid local high temperature leading to slagging or a surge in nitrogen oxides.

[0033] A combustion system 1000 according to a second aspect embodiment of the present invention includes a boiler 200 and a pyrolysis burner 100 according to the first aspect embodiment of the present invention described above.

[0034] The combustion system 1000 according to an embodiment of the present invention, by setting up the combustion system 1000 of the first aspect embodiment described above, has the same technical effect. That is, by arranging the first flue gas outlet 12 and the second flue gas outlet 13 in the vertical direction, internal circulation of flue gas is realized. By arranging the ammonia gas inlet and the air-coal gas inlet 16 adjacent to each other in the vertical direction, in-situ premixing of ammonia with coal / biomass pyrolysis products is realized, which significantly improves the combustion stability and burnout rate of ammonia. Furthermore, setting up the first ammonia gas inlet 14 and the second ammonia gas inlet 15 realizes the staged supply and combustion of ammonia, avoids concentrated heat release, and reduces the generation of nitrogen oxide precursors. By setting the pyrolysis gas outlet 17 at the top of the pyrolysis combustion body 1, the highly active pyrolysis gas can be effectively exported and reused, improving fuel utilization rate. At the same time, it avoids pyrolysis gas retention leading to coking, supports high-proportion ammonia blending, promotes the application of low-carbon / zero-carbon fuels, and helps decarbonize the energy system.

[0035] In some embodiments of the present invention, such as Figure 3 As shown, the boiler 200 has a reburning zone 201 and a main combustion zone 202. The pyrolysis gas outlet 17 of the pyrolysis burner 100 is connected to both the reburning zone 201 and the main combustion zone 202. It can be understood that the main combustion zone 202 is the area where the main fuel (such as pulverized coal or biomass) is burned, releasing most of the heat. The reburning zone 201 is located in a specific area upstream or downstream of the main combustion zone 202. By introducing reducing gas or secondary fuel, under a locally oxygen-deficient or reducing atmosphere, the nitric oxide generated in the main combustion zone 202 is reduced to nitrogen. This achieves multi-functional utilization of the pyrolysis gas, improves resource utilization efficiency, and reduces operating costs.

[0036] In some embodiments of the present invention, the second ammonia port 15, the first flue gas outlet 12, and the second flue gas outlet 13 of the pyrolysis burner 100 are all connected to the main combustion zone 202. Thus, the connection between the second ammonia port 15 and the main combustion zone 202 enables staged ammonia supply, avoiding the localized high temperature and nitrogen oxide surge caused by a single concentrated ammonia supply, improving the ammonia burnout rate, and reducing unburned ammonia escape. The connection between the first flue gas outlet 12 and the second flue gas outlet 13 and the main combustion zone 202 effectively improves combustion efficiency.

[0037] Furthermore, a non-premixed ammonia gas flow is introduced into the main combustion zone 202.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used 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. Therefore, they should not be construed as limitations on this invention.

[0039] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0042] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A pyrolysis burner, characterized in that, include: A pyrolysis combustion body (1) is formed with a combustion chamber (11) and a first flue gas outlet (12) and a second flue gas outlet (13) communicating with the combustion chamber (11). The second flue gas outlet (13) is arranged lower than the first flue gas outlet (12). The pyrolysis combustion body (1) is formed with a first ammonia gas inlet (14), a second ammonia gas inlet (15) and a pulverized air gas inlet (16) communicating with the combustion chamber (11). The first ammonia gas inlet (14), the second ammonia gas inlet (15) and the pulverized air gas inlet (16) are arranged adjacent to each other in the vertical direction. A pyrolysis gas outlet (17) communicating with the combustion chamber (11) is formed at the top of the pyrolysis combustion body (1).

2. The pyrolysis burner according to claim 1, characterized in that, An ignition port (18) is formed on the pyrolysis combustion body (1), and an ignition element (2) is provided at the position of the ignition port (18).

3. The pyrolysis burner according to claim 2, characterized in that, Also includes: The system comprises a first ammonia channel (3), a second ammonia channel (4), and a powder-air channel (5). The first ammonia channel (3) is connected to the first ammonia port (14), the second ammonia channel (4) is connected to the second ammonia port (15), and the powder-air channel (5) is connected to the powder-air port (16).

4. The pyrolysis burner according to claim 3, characterized in that, The first ammonia channel (3), the second ammonia channel (4) and the air-powder channel (5) all extend along the circumferential direction of the pyrolysis combustion body (1).

5. The pyrolysis burner according to claim 4, characterized in that, Also includes: The first flue gas passage (6) and the second flue gas passage (7) are connected to the first flue gas outlet (12) and the second flue gas passage (7) is connected to the second flue gas outlet (13).

6. The pyrolysis burner according to claim 5, characterized in that, Both the first flue gas passage (6) and the second flue gas passage (7) extend along the circumferential direction of the pyrolysis combustion body (1).

7. The pyrolysis burner according to claim 5, characterized in that, The combustion chamber (11) has a first part (111), a second part (112) and a third part (113). The cross-sectional area of ​​the first part (111) gradually increases from top to bottom. The second part (112) is cylindrical. The side of the third part (113) away from the second part (112) is formed as an arc protruding away from the second part (112).

8. A combustion system, characterized in that, include: Boiler (200) and pyrolysis burner according to any one of claims 1-7.

9. The combustion system according to claim 8, characterized in that, The boiler (200) has a reburning zone (201) and a main combustion zone (202), and the pyrolysis gas outlet (17) of the pyrolysis burner is connected to both the reburning zone (201) and the main combustion zone (202).

10. The combustion system according to claim 9, characterized in that, The second ammonia port (15), the first flue gas outlet (12), and the second flue gas outlet (13) of the pyrolysis burner are all connected to the main combustion zone (202).

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