W flame furnace exhaust gas adjustable type pulverized coal staged combustion system
By introducing exhaust air at different locations in the W-type flame boiler combustion system, the problems of insufficient flame undershoot depth and unstable combustion when burning different coal types are solved, and more efficient combustion and lower NOx emissions are achieved, and adaptability and combustion stabilization are improved.
Patent Information
- Application Number
- CN202421345841.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-13
- Publication Date
- 2025-05-13
- Estimated Expiration
- 2034-06-13
AI Technical Summary
When burning different coal types, the existing W-type flame boiler combustion system has problems such as insufficient flame undershoot depth, unstable combustion, high NOx emissions and reduced combustion capacity, which is difficult to adapt to changes in the power grid load and changes in coal types.
By introducing exhaust air at different locations, there are arches, furnace arches and under-arch exhaust air outlets, which are mixed combustion at the upper part of the furnace, furnace arches and coal pulverized burners and combustion at the lower part of the furnace, to adjust the flame undershoot depth and combustion stability.
It achieves sufficient flame undershoot depth, stable combustion, and adjustable flame center, which improves combustion efficiency, reduces NOx emissions, improves coal types adaptability, and has a certain low-load and stable combustion capability to meet peak shaving requirements.
Smart Images
Figure CN222864985U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a W-flame furnace pulverized coal graded combustion system, in particular to a W-flame furnace exhaust gas adjustable pulverized coal graded combustion system. Background Art
[0002] The W-type flame boiler is a power station boiler suitable for burning lean coal and anthracite and other difficult-to-burn coals. The coal powder burns in the furnace to form a "W"-shaped flame combustion, which increases the time that the coal powder particles stay in the furnace and helps the coal powder burn out. However, anthracite and lean coal have low volatile matter content, and their ignition and burnout characteristics are poor, and it takes a long time to burn out. The existing combustion device has a wind curtain-type air distribution under the arch, low speed, and direction that cannot be adjusted. The exhaust air is located on the furnace arch. In actual operation, there are problems such as insufficient flame downstroke depth, late ignition of coal powder airflow, unstable combustion, coking in the furnace, and high carbon content of fly ash combustibles. In order to ensure the burnout of coal powder, the main combustion area is usually laid with a guard belt to maintain a high furnace temperature, which in turn leads to high NOx generated by combustion.
[0003] As the demand for grid capacity increases, the difference between peak and valley loads in the grid gradually increases, and the demand for peak-shaving power sources also gradually increases. More and more W-type flame boilers are involved in peak-shaving operation, and the units have to lower the minimum stable combustion load without oil injection, and need to mix a certain amount of high-volatile coal. The traditional W-type flame boiler combustion system is difficult to adapt to new coal types, and the combustion stability becomes worse, and the stable combustion ability is reduced.
[0004] In addition, due to changes in the coal market, in order to improve the economy of the unit, the boiler has to mix or burn high-volatile bituminous coal. When the traditional W-flame boiler combustion system remains unchanged, there are problems such as insufficient flame downstroke depth, premature combustion, unstable flame center, serious furnace coking, high-temperature heating surface overheating, and water-cooled wall cracking, making it difficult for the boiler to adapt. As a result, the unit cannot adapt to the new coal type and the economy is greatly reduced. Although the above problems can be alleviated to a certain extent through combustion adjustment tests, the problem cannot be fundamentally solved because the combustion organization mode has not changed. Summary of the invention
[0005] The purpose of the utility model is to provide a W-flame furnace exhaust gas adjustable pulverized coal graded combustion system in view of the above-mentioned deficiencies in the prior art. It introduces exhaust gas wind at different positions, has the advantages of sufficient flame downstroke depth, stable combustion, and adjustable flame center, can improve combustion efficiency, adjust boiler steam temperature, reduce boiler NOx emissions, and improve coal type adaptability. It has a certain low-load stable combustion capability and can meet peak regulation requirements.
[0006] In order to achieve the above-mentioned purpose, the utility model provides a W-flame furnace exhaust gas adjustable type pulverized coal graded combustion system, comprising a bellows, a furnace, a pulverized coal pipeline, a concentration and separation device, an exhaust gas air pipeline, a concentrated side pulverized coal pipeline, a pulverized coal burner and a burner nozzle arranged in an opening of a water-cooled wall on a furnace arch; the characteristics are: an upper arch exhaust gas air nozzle is arranged in the opening of the water-cooled wall above the furnace arch, a furnace arch exhaust gas air nozzle is arranged in the opening of the water-cooled wall of the furnace arch, and a lower arch exhaust gas air nozzle is arranged in the opening of the water-cooled wall below the furnace arch, and each exhaust gas air nozzle is connected to the exhaust gas air pipeline through its own regulating valve.
[0007] When in use, at different combustion stages of the boiler, while most of the pulverized coal and part of the primary air mixture enters the pulverized coal burner to form the main flame, the exhaust air can be introduced separately through the exhaust air nozzles on the arch, the exhaust air nozzles on the furnace arch and the exhaust air nozzles under the arch, so that it can be burned in the upper part of the furnace, mixed with the pulverized coal burner in the furnace arch and burned in the lower part of the furnace.
[0008] It can realize low-load stable combustion and adjust steam temperature to ensure that steam temperature requirements are met. It has a certain low-load stable combustion capability and can meet peak load requirements. When the boiler changes due to coal type, it has the advantages of sufficient flame downstroke depth, stable combustion, and adjustable flame center, which can improve combustion efficiency and coal type adaptability. According to emission needs, it can reduce furnace temperature, reduce NOx generation, increase exhaust gas combustion stroke, and reduce fly ash combustibles.
[0009] As a further improvement of the utility model, furnace arch exhaust air nozzles are provided in front of and behind the burner nozzles, and each furnace arch exhaust air nozzle is provided in its own water-cooled wall opening; the position of the flame center can be further adjusted, and the flame downstroke depth and combustion stability can be ensured when the coal type changes;
[0010] As a further improvement of the utility model, the burner nozzle is tilted downward or arranged vertically downward; the furnace flame fullness and the flame center can be adjusted to meet the needs of burning different types of coal;
[0011] To sum up, the utility model introduces exhaust air at different positions, which has the advantages of sufficient flame downstroke depth, stable combustion, and adjustable flame center. It can improve combustion efficiency, adjust boiler steam temperature, reduce boiler NOx emissions, and improve coal type adaptability. It has a certain low-load stable combustion capability and can meet peak regulation requirements. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 It is a structural schematic diagram of an embodiment of the utility model. DETAILED DESCRIPTION
[0013] The utility model is further described below in conjunction with the accompanying drawings.
[0014] like Figure 1As shown, a W-flame furnace exhaust gas adjustable pulverized coal graded combustion system of this embodiment comprises a wind box 1, a furnace 2, a pulverized coal pipeline 3, a concentration and separation device 4, an exhaust gas air pipeline 5, a concentrated side pulverized coal pipeline 6, a pulverized coal burner 7 and a burner nozzle 8 arranged in a water-cooled wall opening 10 on a furnace arch 9, and the burner nozzle 8 is arranged vertically downward; an arch exhaust gas air nozzle 11 is arranged in the water-cooled wall opening above the furnace arch 9, and furnace arch exhaust gas air nozzles 12 and 13 are arranged in the furnace arch water-cooled wall openings in front of and behind the burner nozzle 8, and an arch lower exhaust gas air nozzle 14 is arranged in the water-cooled wall opening below the furnace arch, and each exhaust gas air nozzle 11-14 is connected to the exhaust gas air pipeline 5 through a respective regulating valve 15 or 16 or 17 or 18.
[0015] When in use, the mixture of most of the pulverized coal and part of the primary air separated by the concentration and separation device 4 enters the pulverized coal burner 7 through the concentrated side pulverized coal pipeline 6, and is sent into the furnace 2 through the burner nozzle 8 to burn and form the main flame;
[0016] When the W-flame boiler is in the low-load stage: close the regulating valves 16-18 to allow a small amount of exhaust air to enter the exhaust air nozzle 11. On the one hand, the exhaust air that is not conducive to stable combustion is kept away from the main combustion zone, and the stable combustion ability of the pulverized coal burner 7 is improved, thereby achieving low-load stable combustion and meeting the peak load requirements. On the other hand, the exhaust gas contains part of the pulverized coal, which is burned in the upper part of the furnace, and the steam temperature can be adjusted to ensure that the steam temperature requirements are met at different boiler load stages.
[0017] When the W-flame boiler is in the stage of controlling NOx emission and fly ash combustible emission: close the regulating valves 15-17, allow a small amount of exhaust air to enter the exhaust air nozzle 14, guide the exhaust gas downward and make it burn in the lower part of the furnace, which can reduce the furnace temperature, reduce NOx generation, increase the exhaust gas combustion stroke, and reduce fly ash combustibles;
[0018] When the W-flame boiler is in the stage of burning different types of coal: by flexibly adjusting the regulating valves 15-18, a small amount of pulverized coal can be flexibly entered into the exhaust air nozzles 11-14, giving full play to the adjustability of the burner, the pulverized coal concentration can be adjusted, and the exhaust air has a guiding effect on the main flame, which has the advantages of sufficient flame downstroke depth and stable combustion, and can improve the combustion efficiency. In addition, the position of the flame center can be further adjusted by flexibly using the exhaust air nozzles 12 and 13. When the coal type changes, the flame downstroke depth and combustion stability can also be guaranteed, thereby improving the adaptability of the coal type;
[0019] The utility model can also arrange the burner nozzle 8 to be tilted downward, which can further adjust the furnace flame fullness and flame center to meet the needs of burning different types of coal; the number of pulverized coal burners and nozzles, and the number of exhaust gas nozzles are set according to needs; it is explained through the above embodiments, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the utility model to the scope of the described embodiments.
Claims
1. A W-flame furnace exhaust gas adjustable type pulverized coal graded combustion system, comprising a wind box, a furnace, a pulverized coal pipeline, a concentration and separation device, an exhaust gas air pipeline, a concentrated side pulverized coal pipeline, a pulverized coal burner and a burner nozzle arranged in an opening of a water-cooled wall on a furnace arch; characterized in that: An upper arch exhaust air nozzle is arranged in the water-cooled wall opening above the furnace arch, an arch exhaust air nozzle is arranged in the water-cooled wall opening of the furnace arch, and a lower arch exhaust air nozzle is arranged in the water-cooled wall opening below the furnace arch. Each exhaust air nozzle is connected to the exhaust air duct through its own regulating valve.
2. A W-flame furnace exhaust gas adjustable pulverized coal graded combustion system as claimed in claim 1, characterized in that: Arch exhaust air nozzles are provided in front of and behind the burner nozzles, and each arch exhaust air nozzle is provided in a respective water-cooled wall opening.
3. A W-flame furnace exhaust gas adjustable pulverized coal graded combustion system as claimed in claim 1 or 2, characterized in that: The burner nozzle is inclined downward or arranged vertically downward.