A high-temperature flue gas bypass system

Abstract

This utility model relates to the field of economizer bypass flue technology, and more particularly to a high-temperature flue gas bypass system. A boiler bypass flue is provided between the outlet of the boiler furnace outlet flue and the inlet of the SCR denitrification reactor. The upper end of the boiler bypass flue is connected to the inlet horizontal flue, and the end of the inlet horizontal flue is connected to the outlet flue through a bypass flue ash conveying assembly. The bypass flue ash conveying assembly includes a vertical plate, the lower end of which is fixedly connected to an inclined plate. The included angle between the vertical plate and the inclined plate is α. The sides of the vertical plate and the inclined plate are fixedly connected to a sealing plate. The sealing plate is fixedly connected to the inlet horizontal flue. A bypass flue damper is installed between the two sealing plates. The bypass flue damper includes a rotating shaft, which is fixedly connected to an upper baffle and a lower baffle. The length of the upper baffle is equal to the distance from the rotating shaft to the top plate of the inlet horizontal flue, and the length of the lower baffle is greater than the distance from the rotating shaft to the bottom plate of the inlet horizontal flue.

Description

Technical Field

[0001] This utility model relates to the field of economizer bypass flue technology, and in particular to a high-temperature flue gas bypass system. Background Technology

[0002] Currently, the participation of thermal power plants in flexible peak shaving has become an inevitable trend, with the primary goal of reducing the minimum technical output of the units. Existing widely used flue gas denitrification technology (SCR technology), due to catalyst activity and other factors, typically operates at temperatures between 310℃ and 420℃. However, under low load conditions (generally below 50% of rated load), the flue gas temperature cannot meet this requirement. To increase the inlet flue gas temperature of the SCR system under low load conditions and achieve full-load operation of the SCR system, most coal-fired power plants adopt an economizer bypass modification scheme. This involves installing dampers on the economizer bypass flue to regulate the amount of high-temperature flue gas at the SCR unit inlet. Generally, under high boiler load conditions, the economizer bypass dampers are closed; under low boiler load conditions, when the flue gas temperature is lower than the minimum ammonia injection temperature of the catalyst, the dampers are opened. However, in actual operation, the economizer... When the economizer bypass flue damper is closed, a "dead zone" is formed at the front end of the damper, resulting in severe ash accumulation at the horizontal flue inlet of the bypass flue. If ash accumulates in the horizontal section of the economizer bypass flue for a long time, it can easily cause the damper to become mechanically stuck. This means that when the unit is under high load and the damper needs to be completely closed, the damper may not close tightly, and high-temperature flue gas will enter the SCR denitrification reactor through the economizer bypass flue, causing local overheating of the flue gas and affecting catalyst efficiency. Furthermore, when the unit is under low load and the damper needs to be opened, it may not be able to open completely, or the resistance of the bypass flue may increase due to severe ash accumulation, preventing the formation of an effective pressure differential. This results in less high-temperature flue gas entering the SCR denitrification reactor, and the flue gas temperature may not meet the denitrification operation requirements. Utility Model Content

[0003] This invention proposes a high-temperature flue gas bypass system.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A high-temperature flue gas bypass system includes a boiler furnace. The boiler furnace, after passing through a boiler furnace outlet flue, is sequentially connected to a low-temperature superheater, a boiler economizer, and an SCR denitrification reactor. A boiler bypass flue is provided between the outlet of the boiler furnace outlet flue and the inlet of the SCR denitrification reactor. A main damper is installed on the connecting flue between the boiler economizer and the SCR denitrification reactor. The upper end of the boiler bypass flue is connected to an inlet horizontal flue, and the end of the inlet horizontal flue is connected to the outlet flue via a bypass flue ash conveying assembly. The bypass flue conveys ash... The component includes a vertical plate, the lower end of which is fixedly connected to an inclined plate. The included angle between the vertical plate and the inclined plate is α. The sides of the vertical plate and the inclined plate are fixedly connected to a sealing plate. The sealing plate is fixedly connected to an inlet horizontal flue. A bypass flue damper is installed between the two sealing plates. The bypass flue damper includes a rotating shaft, which is fixedly connected to an upper baffle and a lower baffle. The length of the upper baffle is equal to the distance from the rotating shaft to the top plate of the inlet horizontal flue, and the length of the lower baffle is greater than the distance from the rotating shaft to the bottom plate of the inlet horizontal flue.

[0006] Furthermore, the inlet horizontal flue includes a top plate, with a side plate fixed on each side of the top plate. The lower end of the side plate is fixedly connected to the bottom plate. The length of the side plate is equal to the length of the bottom plate, the length of the top plate is greater than the length of the bottom plate, and the width of the top plate is equal to the width of the bottom plate.

[0007] Furthermore, the width of the upper baffle is equal to the width of the lower baffle, and the width of the upper baffle is not less than the width of the top plate.

[0008] Beneficial effects: By opening the main damper, the flue gas leaves the boiler furnace and passes sequentially through the boiler furnace outlet flue, the low-temperature superheater, the boiler economizer, and then enters the SCR denitrification reactor. Under low-load conditions, the bypass flue damper is opened, and the high-temperature flue gas enters the boiler bypass flue after passing through the bypass flue inlet horizontal flue. After flowing out, it merges with the main flue gas at the economizer outlet in the SCR denitrification reactor. Under high-load conditions, the bypass flue damper is closed, and the boiler furnace outlet flue, the bypass flue inlet horizontal flue, and the bypass flue ash conveying channel form a flow channel, avoiding ash accumulation in the bypass flue inlet horizontal flue. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the structure of this utility model;

[0010] Figure 2 This is a utility model Figure 1 Enlarged view at point A1;

[0011] Figure 3 This is a schematic diagram of the ash conveying components of the inlet horizontal flue and bypass flue in this utility model;

[0012] Figure 4 This utility model Figure 3 The right view;

[0013] Figure 5 This is an enlarged view of point A2 in this utility model;

[0014] Figure 6 This utility model Figure 4 Enlarged image of BB;

[0015] Attached reference numerals: 1 Boiler furnace, 2 Outlet flue, 3 Low-temperature superheater, 4 Boiler economizer, 5 Main damper, 6 SCR denitrification reactor, 7 Boiler bypass flue, 8 Inlet horizontal flue, 9 Bypass flue damper, 10 Bypass flue ash conveying assembly, 11 Connecting flue.

[0016] 801 Top plate, 802 Side plate, 803 Bottom plate;

[0017] 901 Rotating shaft, 902 Upper baffle, 903 Lower baffle;

[0018] 1001 Vertical plate, 1002 Inclined plate, 1003 Closed plate. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0020] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model 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 utility model.

[0021] Reference Figures 1-6A high-temperature flue gas bypass system includes a boiler furnace 1. The boiler furnace 1 is connected in sequence to a low-temperature superheater 3, a boiler economizer 4, and an SCR denitrification reactor 6 via a boiler furnace 1 outlet flue 2. A boiler bypass flue 7 is provided between the outlet of the boiler furnace 1 outlet flue 2 and the inlet of the SCR denitrification reactor 6. A main damper 5 is installed on the connecting flue 11 between the boiler economizer 4 and the SCR denitrification reactor 6. The upper end of the boiler bypass flue 7 is connected to an inlet horizontal flue 8. The end of the inlet horizontal flue 8 is connected to the outlet flue 2 via a bypass flue ash conveying assembly 10. The bypass flue ash conveying assembly 10 includes a vertical plate 1001, the lower end of which is fixedly connected to an inclined plate 1002. The included angle between the vertical plate 1001 and the inclined plate 1002 is α, and the range of α is [120-150]°, preferably 135°. The sides of the vertical plate 1001 and the inclined plate 1002 are fixedly connected to the sealing plate 1003. The sealing plate 1003 is fixedly connected to the inlet horizontal flue 8. A bypass flue damper 9 is installed between the two sealing plates 1003. The bypass flue damper 9 includes a rotating shaft 901. The rotating shaft 901 is fixedly connected to the upper baffle 902 and the lower baffle 903. The length of the upper baffle 902 is equal to the distance from the rotating shaft 901 to the top plate 801 of the inlet horizontal flue 8. The length of the lower baffle 903 is greater than the distance from the rotating shaft 901 to the bottom plate 803 of the inlet horizontal flue 8. The length of the lower baffle 903 is greater than the length of the upper baffle 902. Through the longer lower baffle 903, when the bypass flue damper 9 is closed, the lower baffle 903 contacts the vertical plate 1001. The vertical plate 1001 can limit the movement of the lower baffle 903.

[0022] The inlet horizontal flue 8 includes a top plate 801, and a side plate 802 is fixed on each side of the top plate 801. The lower end of the side plate 802 is fixedly connected to the bottom plate 803. The length of the side plate 802 is equal to the length of the bottom plate 803. The length of the top plate 801 is greater than the length of the bottom plate 803. The width of the top plate 801 is equal to the width of the bottom plate 803.

[0023] The width of the upper baffle 902 is equal to the width of the lower baffle 903, and the width of the upper baffle 902 is not less than the width of the top plate 801.

[0024] When the bypass flue inlet horizontal flue 8 is not equipped with a bypass flue ash conveying channel, under high load conditions, the bypass flue damper 9 will be closed, creating a "dead zone" in the bypass flue inlet horizontal flue 8, causing severe ash accumulation in this area. In this invention, the ash-containing flue gas will flow back into the boiler furnace 1 outlet flue 2 through the bypass flue ash conveying channel, avoiding the problems of ash accumulation in the bypass flue inlet horizontal flue 8 and mechanical jamming of the damper. It can also avoid the problems of local overheating of flue gas under high load and failure of flue gas temperature to meet the denitrification operation requirements under low load.

[0025] In this invention, when the main damper 5 is opened, the flue gas leaves the boiler furnace 1 and passes sequentially through the boiler furnace 1 outlet flue 2, the low-temperature superheater 3, the boiler economizer 4, and then enters the SCR denitrification reactor 6. When the unit is under low load, the bypass flue damper 9 is opened, and the high-temperature flue gas from the boiler enters the boiler bypass flue 7 after passing through the bypass flue inlet horizontal flue 8. After flowing out, it merges with the main flue gas from the economizer outlet in the SCR denitrification reactor 6. When the unit is under high load, the bypass flue damper 9 is closed, and the boiler furnace 1 outlet flue 2, the bypass flue inlet horizontal flue 8, and the bypass flue ash conveying channel form a flow channel, which avoids ash accumulation in the bypass flue inlet horizontal flue 8.

[0026] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A high temperature flue gas bypass system characterized by: The boiler includes a boiler furnace, which, after passing through the boiler furnace outlet flue, is sequentially connected to a low-temperature superheater, a boiler economizer, and an SCR denitrification reactor. A boiler bypass flue is installed between the outlet of the boiler furnace outlet flue and the inlet of the SCR denitrification reactor. A main damper is installed on the connecting flue between the boiler economizer and the SCR denitrification reactor. The upper end of the boiler bypass flue is connected to the inlet horizontal flue, and the end of the inlet horizontal flue is connected to the outlet flue through a bypass flue ash conveying assembly. The bypass flue ash conveying assembly includes a vertical... A straight plate is formed, with its lower end fixedly connected to an inclined plate. The included angle between the vertical plate and the inclined plate is α. The sides of the vertical plate and the inclined plate are fixedly connected to a sealing plate. The sealing plate is fixedly connected to the inlet horizontal flue. A bypass flue damper is installed between the two sealing plates. The bypass flue damper includes a rotating shaft, which is fixedly connected to an upper baffle and a lower baffle. The length of the upper baffle is equal to the distance from the rotating shaft to the top plate of the inlet horizontal flue, and the length of the lower baffle is greater than the distance from the rotating shaft to the bottom plate of the inlet horizontal flue.

2. A high temperature flue gas bypass system according to claim 1, characterised in that: The inlet horizontal flue includes a top plate, with a side plate fixed on each side of the top plate. The lower end of the side plate is fixedly connected to the bottom plate. The length of the side plate is equal to the length of the bottom plate, the length of the top plate is greater than the length of the bottom plate, and the width of the top plate is equal to the width of the bottom plate.

3. A high temperature flue gas bypass system according to claim 1, characterized in that: The width of the upper baffle is equal to the width of the lower baffle, and the width of the upper baffle is not less than the width of the top plate.

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