Boiler combustion system with flexible and accurate air supply structure

Abstract

The application discloses a boiler combustion system with a flexible and accurate air supply structure, and relates to the technical field of thermal power generation. The boiler combustion system comprises a furnace, a SOFA air duct and a main combustion zone secondary air duct fixed on one side of the furnace, and a secondary large air box fixed between the SOFA air duct and the main combustion zone secondary air duct, wherein the SOFA air duct and the main combustion zone secondary air duct are provided with an air supply combustion mechanism at one end close to the furnace. Through the rotation of single SOFA zone guide vanes and single main combustion zone guide vanes, and the guidance of upper and lower arc surfaces in the SOFA zone extension pipe and the main combustion zone extension pipe, air can be accurately and orderly supplied into the furnace through the air door, so that the required air quantity for pulverized coal combustion is met. The boiler combustion system is more flexible to use, the number of guide vanes and actuators is reduced, and the procurement and operation costs of the boiler combustion system are reduced.

Description

Technical Field

[0001] This application relates to the technical field, and in particular to a boiler combustion system with a flexible and precise air delivery structure. Background Technology

[0002] A boiler combustion system refers to the equipment and corresponding flue gas, air, and coal (pulverized coal) pipelines required to ensure complete combustion of fuel within the boiler furnace and to discharge the generated flue gas into the atmosphere. The combustion system should be designed according to the type of fuel used (solid, liquid, or gaseous fuel), the type of power plant boiler, and the combustion method. It should rationally select the process flow, determine the specifications and quantity of equipment and pipelines, and fully consider necessary margins to ensure the boiler and combustion system operate under the safest and most economical conditions. It is commonly used in thermal power generation and other fields.

[0003] Patent CN217031177U discloses "a novel boiler combustion system with a flexible and precise air supply structure. By setting multiple guide vanes in the SOFA air duct and the secondary air duct of the main combustion zone to achieve precise air supply, the flow field in the boiler air supply duct can be flexibly adjusted according to the load change to adapt to the real-time fluctuation of the boiler load. This avoids a large amount of air that is not involved in combustion from leaking into the furnace, and makes the excess air coefficient accurately reflect the amount of air required for pulverized coal combustion. The combustion in the furnace is optimized, and the boiler efficiency is improved under wide load fluctuations. The emission concentration of nitrogen oxides at the furnace outlet is reduced, the boiler is guaranteed to have stable and safe combustion, and the peak and frequency regulation requirements of the power grid are met. This system is adapted to the new low-carbon power system with new energy as the main body and petrochemical energy as the auxiliary."

[0004] Regarding the aforementioned technologies, the inventors believe that precise air delivery relies on multiple guide vanes in the SOFA duct and the secondary air duct of the main combustion zone. These multiple guide vanes require multiple actuators for joint control, but actuators are typically expensive. Therefore, the setup of multiple actuators and multiple guide vanes increases the procurement and operating costs of the boiler combustion system, thus requiring improvement. Utility Model Content

[0005] To address the aforementioned issues, this application provides a boiler combustion system with a flexible and precise air delivery structure.

[0006] The boiler combustion system with a flexible and precise air supply structure provided in this application adopts the following technical solution:

[0007] A boiler combustion system with a flexible and precise air supply structure includes a furnace, a SOFA air duct and a main combustion zone secondary air duct fixedly installed on one side of the furnace, and a secondary large air box fixedly installed between the SOFA air duct and the main combustion zone secondary air duct. The SOFA air duct and the main combustion zone secondary air duct are provided with an air supply combustion mechanism at one end near the furnace. A plurality of SOFA zone extension pipes are provided on one side of the air supply combustion mechanism of the SOFA air duct. An upper arc surface is formed between the ends of the plurality of SOFA zone extension pipes away from the air supply combustion mechanism. SOFA zone guide vanes for precise air supply are rotatably installed in the SOFA air duct. One end of the SOFA zone guide vanes is engaged with the upper arc surface of the plurality of SOFA zone extension pipes.

[0008] The secondary air duct of the main combustion zone has several main combustion zone extension pipes on one side. A lower arc surface is formed between the ends of these extension pipes facing away from the air supply and combustion mechanism. A main combustion zone guide vane for precise air supply is rotatably mounted inside the secondary air duct, with one end of the guide vane engaging with the lower arc surface of the extension pipes.

[0009] By adopting the above technical solution, the rotation of a single SOFA zone guide vane and a single main combustion zone guide vane, combined with the guidance of the upper and lower arc surfaces inside the SOFA zone extension pipe and the main combustion zone extension pipe, can accurately and systematically deliver air into the furnace through the damper to meet the air volume required for pulverized coal combustion. This makes it more flexible to use and reduces the number of guide vanes and actuators, thereby reducing the procurement and operating costs of the boiler combustion system.

[0010] Preferably, the air supply and combustion mechanism includes multiple SOFA combustion layers located at one end of the SOFA duct near the furnace, and multiple pulverized coal combustion layers and multiple main combustion zone combustion layers staggered at one end of the secondary air duct in the main combustion zone near the furnace. Each SOFA combustion layer is equipped with a SOFA damper and a SOFA air burner, each pulverized coal combustion layer is equipped with a pulverized coal pipe and a pulverized coal burner, and each main combustion zone combustion layer is equipped with a main combustion zone secondary air damper and a main combustion zone secondary air burner.

[0011] By adopting the above technical solution, in the main combustion zone, pulverized coal enters the pulverized coal burner through the pulverized coal pipeline and is then injected into the furnace. The air required for pulverized coal combustion enters the secondary air burner of the main combustion zone through the secondary large air box, the secondary air duct of the main combustion zone, and the secondary air damper of the main combustion zone and is then injected into the furnace, where the air mixes with the pulverized coal for combustion. In the burnout zone, air enters the SOFA air burner through the secondary large air box, the SOFA air duct, and the SOFA air damper and is then injected into the furnace, where it mixes with the unburned pulverized coal for continued combustion.

[0012] Preferably, the SOFA air duct and the secondary air duct of the main combustion zone are provided with an auxiliary cleaning mechanism. The auxiliary cleaning mechanism includes several scraper rings that are slidably disposed in the SOFA air duct and the secondary air duct of the main combustion zone. The SOFA zone guide vanes and the main combustion zone guide vanes are rotatably provided with two sets of inclined transmission rods between themselves and the scraper rings.

[0013] By adopting the above technical solution, the rotation of the SOFA zone guide vanes and the main combustion zone guide vanes during precise air delivery, in conjunction with the connection of the transmission rod, can drive the scraper rings in the SOFA air duct and the secondary air duct of the main combustion zone to move laterally. After moving, the scraper rings can scrape off the attached materials in the SOFA air duct and the secondary air duct of the main combustion zone.

[0014] Preferably, an annular sponge is fixedly installed in the annular groove on the outer side of the scraper ring, and the inner wall of the SOFA air duct and the secondary air duct of the main combustion zone abuts against the outer wall of the annular sponge. Multiple connecting rods are fixedly installed between the scraper rings.

[0015] By adopting the above technical solution, the scraper ring can move and drive the annular sponge to move as well. The moved annular sponge can wipe and clean the SOFA air duct and the secondary air duct of the main combustion zone, thereby reducing the cleaning intensity of the boiler combustion system for the staff in the later stage.

[0016] In summary, this application includes at least one of the following beneficial technical effects:

[0017] 1. By rotating a single SOFA zone guide vane and a single main combustion zone guide vane, and with the guidance of the upper and lower arc surfaces inside the SOFA zone extension pipe and the main combustion zone extension pipe, air can be precisely and systematically delivered into the furnace through the damper to meet the air volume required for pulverized coal combustion. This makes it more flexible to use and reduces the number of guide vanes and actuators, thereby reducing the procurement and operating costs of the boiler combustion system.

[0018] 2. By rotating the guide vanes in the SOFA zone and the guide vanes in the main combustion zone during precise air delivery, and in conjunction with the transmission rod, the scraper rings in the SOFA duct and the secondary air duct of the main combustion zone can be moved laterally. After moving, the scraper rings can scrape off the attached materials in the SOFA duct and the secondary air duct of the main combustion zone. The movement of the scraper rings can also drive the annular sponge to move. The moved annular sponge can wipe and clean the SOFA duct and the secondary air duct of the main combustion zone, thereby reducing the cleaning intensity of the boiler combustion system for the staff in the later stage, which is convenient and practical. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of a boiler combustion system with a flexible and precise air supply structure according to an embodiment of this application;

[0020] Figure 2This is a front view connection diagram of the internal structure of a boiler combustion system with a flexible and precise air supply structure according to an embodiment of this application;

[0021] Figure 3 The embodiments of this application mainly embody Figure 2 Enlarged view of the structure of A in the middle;

[0022] Figure 4 This is a right-side view of the scraping ring, which is the main embodiment of this application.

[0023] Attached reference numerals: 1. Secondary large air box; 2. SOFA air duct; 3. SOFA damper; 4. SOFA air burner; 5. Pulverized coal burner; 6. Pulverized coal pipeline; 7. Secondary air burner in the main combustion zone; 8. Secondary air damper in the main combustion zone; 9. Secondary air duct in the main combustion zone; 10. Furnace; 11. SOFA zone extension pipe; 12. Main combustion zone extension pipe; 13. SOFA zone guide vane; 14. Main combustion zone guide vane; 15. Scraper ring; 16. Transmission rod; 17. Annular sponge; 18. Connecting rod. Detailed Implementation

[0024] The following is in conjunction with the appendix Figures 1-4 This application will be described in further detail.

[0025] This application discloses a boiler combustion system with a flexible and precise air delivery structure.

[0026] A boiler combustion system with a flexible and precise air supply structure, referring to Figure 1-2 It includes a furnace 10, a SOFA air duct 2, a main combustion zone secondary air duct 9, and a secondary large air box 1. The SOFA air duct 2 and the main combustion zone secondary air duct 9 are fixedly installed on one side of the furnace 10 and are connected. The secondary large air box 1 is fixedly installed between the SOFA air duct 2 and the main combustion zone secondary air duct 9 and are connected. The SOFA air duct 2 and the main combustion zone secondary air duct 9 are provided with an air supply and combustion mechanism at the end near the furnace 10.

[0027] Reference Figure 1-2 The air supply and combustion mechanism includes a multi-layer SOFA combustion layer located at one end of the SOFA air duct 2 near the furnace 10, and a multi-layer pulverized coal combustion layer and a multi-layer main combustion zone combustion layer staggered at one end of the secondary air duct 9 in the main combustion zone near the furnace 10. Each SOFA combustion layer is equipped with a SOFA air damper 3 and a SOFA air burner 4. Each pulverized coal combustion layer is equipped with a pulverized coal pipe 6 and a pulverized coal burner 5. Each main combustion zone combustion layer is equipped with a main combustion zone secondary air damper 8 and a main combustion zone secondary air burner 7.

[0028] In the main combustion zone, pulverized coal enters the pulverized coal burner 5 through the pulverized coal pipeline 6 and is then injected into the furnace 10. The air required for pulverized coal combustion enters the secondary air burner 7 through the secondary large air box 1, the secondary air duct 9 of the main combustion zone, and the secondary air damper 8 of the main combustion zone and is then injected into the furnace 10. The air mixes with the pulverized coal for combustion. In the burnout zone, air enters the SOFA air burner 4 through the secondary large air box 1, the SOFA air duct 2, and the SOFA air damper 3 and is then injected into the furnace 10. It mixes with the unburned pulverized coal and continues to burn. This is a public technology and will not be described in detail here.

[0029] Reference Figure 1-2 The SOFA duct 2 has several SOFA zone extension pipes 11 on one side of the air supply and combustion mechanism. The ends of the SOFA zone extension pipes 11 facing away from the air supply and combustion mechanism are provided with an upper arc surface. SOFA zone guide vanes 13 for precise air supply are rotatably installed inside the SOFA duct 2. One end of the SOFA zone guide vane 13 is engaged with the upper arc surface of the SOFA zone extension pipes 11. The SOFA zone guide vane 13 is driven to rotate by an actuator located outside the SOFA duct 2. By controlling the rotation angle of the SOFA zone guide vane 13, the position of the SOFA zone guide vane 13 engaged with the upper arc surface of the SOFA zone extension pipes 11 can be adjusted, so that the air flow direction changes after passing through the SOFA zone guide vane 13, thereby changing the air flow field inside the SOFA duct 2. This can achieve the actual air volume required by each layer of SOFA damper 3, and achieve the purpose of flexible and precise air supply.

[0030] Reference Figure 1-2 The secondary air duct 9 of the main combustion zone has several main combustion zone extension pipes 12 on one side of the air supply and combustion mechanism. The ends of the extension pipes 12 facing away from the air supply and combustion mechanism have a lower arc surface. The secondary air duct 9 of the main combustion zone has a rotating guide vane 14 for precise air supply. One end of the guide vane 14 is engaged with the lower arc surface of the extension pipes 12. The guide vane 14 is driven to rotate by an actuator located outside the secondary air duct 9 of the main combustion zone. By controlling the rotation angle of the guide vane 14, the position of the guide vane 14 engaged with the lower arc surface of the extension pipes 12 can be adjusted, so that the air flow direction changes after passing through the guide vane 14, thereby changing the air flow field in the secondary air duct 9 of the main combustion zone. This can achieve the actual air volume required by the secondary air dampers 8 of each main combustion zone, and achieve the purpose of flexible and precise air supply.

[0031] Reference Figure 2-4An auxiliary cleaning mechanism is provided in the SOFA air duct 2 and the secondary air duct 9 of the main combustion zone. The auxiliary cleaning mechanism includes several scraper rings 15 that are slidably installed in the SOFA air duct 2 and the secondary air duct 9 of the main combustion zone. The SOFA zone guide vanes 13 and the main combustion zone guide vanes 14 are rotatably connected to the scraper rings 15 with two sets of inclined transmission rods 16. The SOFA zone guide vanes 13 and the main combustion zone guide vanes 14 can limit the slidingly connected scraper rings 15, so that the scraper rings 15 can only move laterally. Through the rotation of the SOFA zone guide vanes 13 and the main combustion zone guide vanes 14 during precise air delivery, in conjunction with the connection of the transmission rods 16, the scraper rings 15 in the SOFA air duct 2 and the secondary air duct 9 of the main combustion zone can be driven to move laterally. After moving, the scraper rings 15 can scrape off the attached objects in the SOFA air duct 2 and the secondary air duct 9 of the main combustion zone.

[0032] Reference Figure 2-3 An annular sponge 17 is fixedly installed in the annular groove on the outer side of the scraper ring 15. The inner wall of the SOFA air duct 2 and the secondary air duct 9 of the main combustion zone abuts against the outer wall of the annular sponge 17. Multiple connecting rods 18 are fixed between several scraper rings 15. The connecting rods 18 can connect several scraper rings 15 so that the scraper rings 15 can move together. After the scraper rings 15 move, they can drive the annular sponge 17 to move with them. After the annular sponge 17 moves, it can wipe and clean the SOFA air duct 2 and the secondary air duct 9 of the main combustion zone, thereby reducing the cleaning intensity of the boiler combustion system by the staff in the later stage.

[0033] The implementation principle of a boiler combustion system with a flexible and precise air supply structure according to an embodiment of this application is as follows:

[0034] In the main combustion zone, pulverized coal enters the pulverized coal burner 5 through the pulverized coal pipeline 6 and is then injected into the furnace 10. The air required for pulverized coal combustion enters the secondary air burner 7 of the main combustion zone through the secondary large air box 1, the secondary air duct of the main combustion zone 9, and the secondary air damper of the main combustion zone 8 and is then injected into the furnace 10. The air and pulverized coal are mixed and burned.

[0035] In the burnout zone, air enters the SOFA air burner 4 through the secondary large air box 1, SOFA air duct 2, and SOFA air damper 3, and is then injected into the furnace 10, where it mixes with the unburned coal powder and continues to burn.

[0036] By controlling the rotation angle of the SOFA zone guide vane 13, the position of the SOFA zone guide vane 13 abutting against the arc surface of several SOFA zone extension pipes 11 can be adjusted, so that the air flow direction changes after passing through the SOFA zone guide vane 13, thereby changing the air flow field in the SOFA duct 2, which can realize the actual air volume required by each layer of SOFA damper 3, and achieve the purpose of flexible and precise air delivery.

[0037] By controlling the rotation angle of the main combustion zone guide vane 14, the position of the main combustion zone guide vane 14 against the lower arc surface of several main combustion zone extension pipes 12 can be adjusted, so that the air flow direction changes after passing through the main combustion zone guide vane 14, thereby changing the air flow field in the secondary air duct 9 of the main combustion zone. This can achieve the actual air volume required by the secondary air damper 8 of each main combustion zone, and achieve the purpose of flexible and precise air delivery. In this way, the air is precisely and systematically delivered into the furnace 10 through the required air damper to meet the air volume required for pulverized coal combustion.

[0038] The rotation of the SOFA zone guide vanes 13 and the main combustion zone guide vanes 14 during precise air delivery, in conjunction with the connection of the transmission rod 16, can drive the scraper rings 15 in the SOFA air duct 2 and the secondary air duct 9 of the main combustion zone to move laterally. After moving, the scraper rings 15 can scrape off the attached materials in the SOFA air duct 2 and the secondary air duct 9 of the main combustion zone. After the scraper rings 15 move, they can drive the annular sponge 17 to move as well. After moving, the annular sponge 17 can wipe and clean the SOFA air duct 2 and the secondary air duct 9 of the main combustion zone, thereby reducing the cleaning intensity of the boiler combustion system for the staff in the later stage.

[0039] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A boiler combustion system with a flexible and precise air supply structure, comprising a furnace (10), a SOFA air duct (2) and a secondary air duct (9) fixedly disposed on one side of the furnace (10), and a secondary large air box (1) fixedly disposed between the SOFA air duct (2) and the secondary air duct (9), wherein the SOFA air duct (2) and the secondary air duct (9) are provided with an air supply combustion mechanism at the end near the furnace (10), characterized in that: The SOFA duct (2) has several SOFA zone extension pipes (11) on one side of the air supply and combustion mechanism. An upper arc surface is opened between the ends of the several SOFA zone extension pipes (11) that are away from the air supply and combustion mechanism. SOFA zone guide vanes (13) for precise air supply are rotatably provided in the SOFA duct (2). One end of the SOFA zone guide vane (13) is engaged with the upper arc surface of the several SOFA zone extension pipes (11). The secondary air duct (9) of the main combustion zone is provided with a plurality of main combustion zone extension pipes (12) on one side of the air supply combustion mechanism. The ends of the plurality of main combustion zone extension pipes (12) away from the air supply combustion mechanism are provided with a lower arc surface. The secondary air duct (9) of the main combustion zone is provided with a main combustion zone guide vane (14) for precise air supply. One end of the main combustion zone guide vane (14) is engaged with the lower arc surface of the plurality of main combustion zone extension pipes (12).

2. The boiler combustion system with a flexible and precise air supply structure according to claim 1, characterized in that: The air supply and combustion mechanism includes a multi-layer SOFA combustion layer located at one end of the SOFA duct (2) near the furnace (10), and a multi-layer pulverized coal combustion layer and a multi-layer main combustion zone combustion layer staggered at one end of the secondary air duct (9) in the main combustion zone near the furnace (10).

3. A boiler combustion system with a flexible and precise air supply structure according to claim 2, characterized in that: Each SOFA combustion layer is equipped with a SOFA damper (3) and a SOFA air burner (4).

4. A boiler combustion system with a flexible and precise air supply structure according to claim 2, characterized in that: Each of the pulverized coal combustion layers is equipped with pulverized coal pipes (6) and pulverized coal burners (5).

5. A boiler combustion system with a flexible and precise air supply structure according to claim 2, characterized in that: Each of the main combustion zones is equipped with a main combustion zone secondary air damper (8) and a main combustion zone secondary air burner (7).

6. A boiler combustion system with a flexible and precise air supply structure according to claim 1, characterized in that: An auxiliary cleaning mechanism is provided in the SOFA air duct (2) and the secondary air duct (9) of the main combustion zone. The auxiliary cleaning mechanism includes several scraper rings (15) that are slidably disposed in the SOFA air duct (2) and the secondary air duct (9) of the main combustion zone. The SOFA zone guide vane (13) and the main combustion zone guide vane (14) are rotatably provided with two sets of inclined transmission rods (16) between themselves and the scraper rings (15).

7. A boiler combustion system with a flexible and precise air supply structure according to claim 6, characterized in that: An annular sponge (17) is fixedly installed in the annular groove on the outer side of the scraper ring (15), and the inner wall of the SOFA air duct (2) and the secondary air duct (9) of the main combustion zone abuts against the outer wall of the annular sponge (17).

8. A boiler combustion system with a flexible and precise air supply structure according to claim 7, characterized in that: Multiple connecting rods (18) are fixedly provided between several of the scraper rings (15).

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