Novel full-load denitration input flue gas bypass structure
By designing a novel full-load denitrification flue gas bypass structure, and using thermocouple detection and electric damper control to control flue gas mixing, the problems of eddy currents and insufficient flue gas temperature during low-load operation were solved, achieving efficient flue gas denitrification treatment, reducing NOx emissions and ash accumulation, and achieving energy-saving and environmental protection effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- LIAONING DATANG INTERNATIONAL SHENDONG THERMAL POWER CO LTD
- Filing Date
- 2025-05-12
- Publication Date
- 2026-04-17
AI Technical Summary
The existing bypass flue structure causes eddies and "turbulence" when operating at low loads, which affects the flue gas denitrification process, and the flue gas temperature is too low to meet the denitrification operation conditions.
A novel full-load denitrification flue gas bypass structure is designed, including a main pipe, heat exchange components, flue gas intake pipe, bypass pipe and horizontal pipe. The flue gas temperature is detected by thermocouples, and electric dampers are controlled to regulate the inflow of high-temperature flue gas. Combined with guide plates, the flue gas mixing effect is improved to ensure that it is fully mixed and enters the denitrification system.
The increased flue gas denitrification temperature enhanced the denitrification reduction capacity, reduced NOx emissions and ammonia injection volume, decreased ash accumulation, and achieved energy-saving and environmentally friendly flue gas treatment.
Smart Images
Figure CN224126977U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of boiler flue gas treatment, specifically a novel full-load denitrification flue gas bypass structure. Background Technology
[0002] Large power plant boilers often participate in peak shaving, and the inlet flue gas temperature of the SCR denitrification unit will be lower than the full load temperature when operating at low load. When the flue gas temperature is too low to meet the denitrification commissioning conditions, the heat exchange between the heating surface in the boiler tail flue and the flue gas can be reduced by setting up a flue gas bypass duct, thereby increasing the denitrification inlet flue gas temperature and meeting the denitrification commissioning conditions.
[0003] The existing bypass flue structure causes eddies and turbulence when the bypass flue outlet mixes with the economizer outlet flue, affecting the subsequent flue gas denitrification process. Utility Model Content
[0004] The purpose of this invention is to provide a novel full-load denitrification flue gas bypass structure to solve the problems mentioned in the background art.
[0005] To achieve the above objectives, this utility model provides the following technical solution: a novel full-load denitrification flue gas bypass structure, comprising a main pipeline, a heat exchange component fixedly installed inside the main pipeline, and several flue gas extraction pipes connected to one side of the main pipeline, a side branch pipe provided on one side of the main pipeline, and the other end of each flue gas extraction pipe connected to one end of the side branch pipe, a horizontal pipe connected to the bottom of one side of the main pipeline, and the bottom end of the side branch pipe connected to the top end of the horizontal pipe, a mixing component fixedly installed inside the horizontal pipe, and the other end of the horizontal pipe connected to the denitrification system.
[0006] Preferably, each of the smoke extraction pipes is inclined to the side wall of the main pipe, and the bottom of each smoke extraction pipe makes an angle of 10° with the horizontal direction.
[0007] Preferably, each of the smoke extraction pipes is fixedly installed with a non-metallic expansion joint at the end near the side branch pipe and at the end near the horizontal pipe.
[0008] Preferably, each of the smoke extraction pipes and horizontal pipes is fixedly installed with a thermocouple on the side away from the heat exchange component, and the detection end of the thermocouple extends into the inside of the smoke extraction pipe and the horizontal pipe respectively.
[0009] Preferably, the side branch pipe and the horizontal pipe are respectively fixedly installed with a first electric baffle door and a second electric baffle door.
[0010] Preferably, the mixing component includes several first guide plates and second guide plates fixedly connected to the top and bottom of the inner wall of the horizontal tube, and the several first guide plates and second guide plates are arranged in parallel.
[0011] Preferably, a plurality of first guide plates and second guide plates are alternately arranged along the axis of the horizontal pipe, and the bottom end of each first guide plate is fixedly connected to the bottom end of the inner wall of the horizontal pipe, the top end of each second guide plate is fixedly connected to the top end of the inner wall of the horizontal pipe, and the two sides of each first guide plate and second guide plate are respectively attached to the two sides of the inner wall of the horizontal pipe, a gap is left between the top end of each first guide plate and the top end of the inner wall of the horizontal pipe, and a gap is left between the bottom end of each second guide plate and the bottom end of the inner wall of the horizontal pipe.
[0012] Compared with the prior art, the advantages of this utility model are as follows:
[0013] In this invention, high-temperature flue gas enters the main pipe from one end and undergoes heat exchange through a heat exchange component. The cooled flue gas, after heat exchange, enters a horizontal pipe from the bottom of the main pipe and then enters the denitrification system for denitrification treatment. When a thermocouple on one side of the horizontal pipe detects that the flue gas temperature is lower than a preset value, the operator opens the first electric baffle door, allowing a portion of the high-temperature flue gas above the heat exchange component in the main pipe to enter a side branch pipe through a flue gas extraction pipe. This allows the flue gas to mix with the high-temperature flue gas in the horizontal pipe, increasing the temperature for denitrification treatment. To improve the mixing effect of the high-temperature and low-temperature flue gas, multiple first and second guide plates are installed on the inner wall of the horizontal pipe. The S-shaped channel formed by the obstruction of these guide plates extends the transmission time of the low-temperature and high-temperature flue gas within the horizontal pipe, resulting in more thorough and uniform mixing. This improves subsequent denitrification reduction capacity, reduces boiler NOx emissions, decreases ammonia injection, and promotes energy conservation and environmental protection. Each flue gas extraction pipe is inclined at a certain angle to prevent ash accumulation in the horizontal flue and reduce the ash concentration in the flue gas. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the structure of this utility model;
[0015] Figure 2 This is an enlarged schematic diagram of the structure at point A of this utility model.
[0016] In the diagram: 1. Main pipe; 2. Heat exchange assembly; 3. Smoke intake pipe; 4. Side branch pipe; 5. Horizontal pipe; 6. Mixing assembly; 7. First electric damper; 8. Second electric damper; 9. Denitrification system; 61. First guide plate; 62. Second guide plate. Detailed Implementation
[0017] 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.
[0018] Example
[0019] Please see Figures 1-2 The diagram shows a novel full-load denitrification flue gas bypass structure, including a main pipe 1, a heat exchange component 2 fixedly installed inside the main pipe 1, and several flue gas extraction pipes 3 connected to one side of the main pipe 1. A side branch pipe 4 is provided on one side of the main pipe 1, and the other end of each flue gas extraction pipe 3 is connected to one end of the side branch pipe 4. A horizontal pipe 5 is connected to the bottom of one side of the main pipe 1, and the bottom end of the side branch pipe 4 is connected to the top end of the horizontal pipe 5. A mixing component 6 is fixedly installed inside the horizontal pipe 5, and the other end of the horizontal pipe 5 is connected to the denitrification system 9.
[0020] In this embodiment, each smoke extraction pipe 3 is inclined to the side wall of the main pipe 1, and the bottom of each smoke extraction pipe 3 forms an angle of 10° with the horizontal direction. A non-metallic expansion joint is fixedly installed at the end of each smoke extraction pipe 3 near the side branch pipe 4 and at the end of the side branch pipe 4 near the horizontal pipe 5. A thermocouple is fixedly installed on the side of each smoke extraction pipe 3 and the horizontal pipe 5 away from the heat exchange assembly 2, with the detection end of the thermocouple extending into the interior of the smoke extraction pipe 3 and the horizontal pipe 5, respectively. A first electric baffle 7 and a second electric baffle 8 are fixedly installed on the side branch pipe 4 and the horizontal pipe 5, respectively. The mixing assembly 6 includes several components fixedly connected to the top and bottom ends of the inner wall of the horizontal pipe 5. A first guide plate 61 and a second guide plate 62 are arranged in parallel. The first guide plates 61 and the second guide plates 62 are alternately arranged along the axis of the horizontal pipe 5. The bottom end of each first guide plate 61 is fixedly connected to the bottom end of the inner wall of the horizontal pipe 5, and the top end of each second guide plate 62 is fixedly connected to the top end of the inner wall of the horizontal pipe 5. The two sides of each first guide plate 61 and the second guide plate 62 are respectively attached to the two sides of the inner wall of the horizontal pipe 5. A gap is left between the top end of each first guide plate 61 and the top end of the inner wall of the horizontal pipe 5, and a gap is left between the bottom end of each second guide plate 62 and the bottom end of the inner wall of the horizontal pipe 5.
[0021] Furthermore, the high-temperature flue gas enters the main pipe 1 from one end and undergoes a heat exchange process through the heat exchange assembly 2. The heat exchange assembly 2 includes a low-temperature reheater, a low-temperature superheater, and an economizer, which are conventional technologies in this field and will not be described in detail here. After heat exchange, the low-temperature flue gas enters the horizontal pipe 5 from the bottom of the main pipe 1 and then enters the denitrification system 9 for denitrification treatment. When the thermocouple installed on one side of the horizontal pipe 5 detects that the flue gas temperature is lower than the preset value, the operator opens the baffle of the first electric baffle door 7, allowing part of the high-temperature flue gas above the heat exchange assembly 2 in the main pipe 1 to enter the side branch pipe 4 through the flue gas intake pipe 3, thereby passing through the horizontal pipe 4. The high-temperature flue gas in pipe 5 is mixed to increase the temperature of flue gas denitrification treatment. In order to improve the mixing effect of high-temperature flue gas and low-temperature flue gas, multiple first guide plates 61 and second guide plates 62 are set on the inner wall of horizontal pipe 5. The S-shaped channel formed by the obstruction of multiple first guide plates 61 and second guide plates 62 extends the transmission time of low-temperature flue gas and high-temperature flue gas in horizontal pipe 5, thereby making the flue gas mixing more thorough and uniform, improving the subsequent denitrification reduction capacity, reducing boiler NOx emissions, reducing ammonia injection, and saving energy and protecting the environment. Each smoke intake pipe 3 is set at a certain angle to prevent ash accumulation in the horizontal flue of smoke intake pipe 3 and reduce the ash concentration of flue gas.
[0022] The working principle of this utility model is as follows: High-temperature flue gas enters the main pipe 1 from one end and undergoes heat exchange through the heat exchange component 2. The low-temperature flue gas after heat exchange enters the horizontal pipe 5 from the bottom of the main pipe 1 and then enters the denitrification system 9 for denitrification treatment. When the thermocouple installed on one side of the horizontal pipe 5 detects that the flue gas temperature is lower than the preset value, the operator opens the baffle of the first electric baffle door 7, allowing part of the high-temperature flue gas above the heat exchange component 2 in the main pipe 1 to enter the side branch pipe 4 through the smoke intake pipe 3. This allows the flue gas to mix with the high-temperature flue gas in the horizontal pipe 5, thereby increasing the temperature of the flue gas denitrification treatment. This process is designed to increase the temperature of the high-temperature and low-temperature flue gas. To improve the gas mixing effect, multiple first guide plates 61 and second guide plates 62 are installed on the inner wall of the horizontal pipe 5. The S-shaped channel formed by the obstruction of multiple first guide plates 61 and second guide plates 62 extends the transmission time of low-temperature flue gas and high-temperature flue gas in the horizontal pipe 5, thereby making the flue gas mixing more thorough and uniform, improving the subsequent denitrification and reduction capacity, reducing boiler NOx emissions, reducing ammonia injection, and saving energy and protecting the environment. Each smoke intake pipe 3 is set at a certain angle to prevent ash accumulation in the horizontal flue of the smoke intake pipe 3 and reduce the ash concentration of the flue gas. The flow rate of high-temperature flue gas in the side branch pipe 4 can be adjusted by adjusting the angle of the baffle in the first electric baffle door 7.
[0023] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0024] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A novel full-load denitrification flue gas bypass structure, comprising a main pipeline (1), characterized in that: A heat exchange component (2) is fixedly installed inside the main pipe (1), and several smoke extraction pipes (3) are connected to one side of the main pipe (1). A side branch pipe (4) is provided on one side of the main pipe (1), and the other end of each smoke extraction pipe (3) is connected to one end of the side branch pipe (4). A horizontal pipe (5) is connected to the bottom of one side of the main pipe (1), and the bottom end of the side branch pipe (4) is connected to the top end of the horizontal pipe (5). A mixing component (6) is fixedly installed inside the horizontal pipe (5), and the other end of the horizontal pipe (5) is connected to the denitrification system (9).
2. A novel full-load denitration input flue gas bypass structure according to claim 1, characterized in that: Each of the smoke extraction pipes (3) is inclined to the side wall of the main pipe (1), and the bottom of each smoke extraction pipe (3) has an angle of 10° with the horizontal direction.
3. The novel full-load denitration flue gas bypass structure according to claim 2, characterized in that: Each of the smoke extraction pipes (3) is fixedly installed with a non-metallic expansion joint at one end near the side branch pipe (4) and at the other end near the horizontal pipe (5).
4. The novel full-load denitration input flue gas bypass structure according to claim 3, characterized in that: Each of the smoke extraction pipes (3) and the horizontal pipes (5) is fixedly equipped with a thermocouple on the side away from the heat exchange assembly (2), and the detection end of the thermocouple extends into the inside of the smoke extraction pipes (3) and the horizontal pipes (5).
5. The novel full-load denitration input flue gas bypass structure according to claim 4, characterized in that: The side branch pipe (4) and the horizontal pipe (5) are respectively fixedly installed with the first electric baffle door (7) and the second electric baffle door (8).
6. The novel full-load denitration input flue gas bypass structure according to claim 5, characterized in that: The mixing component (6) includes several first guide plates (61) and second guide plates (62) fixedly connected to the top and bottom of the inner wall of the horizontal tube (5), and the several first guide plates (61) and second guide plates (62) are arranged in parallel.
7. The novel full-load denitration input flue gas bypass structure according to claim 6, characterized in that: Several first guide plates (61) and second guide plates (62) are alternately arranged along the axis of the horizontal pipe (5), and the bottom end of each first guide plate (61) is fixedly connected to the bottom end of the inner wall of the horizontal pipe (5), the top end of each second guide plate (62) is fixedly connected to the top end of the inner wall of the horizontal pipe (5), and the two sides of each first guide plate (61) and second guide plate (62) are respectively attached to the two sides of the inner wall of the horizontal pipe (5). A gap is left between the top end of each first guide plate (61) and the top end of the inner wall of the horizontal pipe (5), and a gap is left between the bottom end of each second guide plate (62) and the bottom end of the inner wall of the horizontal pipe (5).