Low-temperature economizer system

Abstract

The invention belongs to the technical field of waste heat recovery, and particularly discloses a low-temperature economizer system. The low-temperature economizer system comprises a flue, an economizer body and a flow guide assembly, the flue is provided with a vertical section and a horizontal section communicating with the bottom end of the vertical section, and the end, close to the horizontal section, of the vertical section is provided with a variable-diameter section with the circulation section gradually decreased. The economizer body is arranged in the vertical section. The flow guide assembly comprises a first flow guide part, a second flow guide part and a third flow guide part, the first flow guide part is arranged on the reducing section and located on the downstream of the economizer body, the second flow guide part is located at the joint of the vertical section and the horizontal section, and the third flow guide part is located on the horizontal section. According to the low-temperature economizer system, ash blocking of the flue and abrasion of the economizer can be reduced, and the service life is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of waste heat recovery, and in particular relates to a low-temperature economizer system. Background Art

[0002] In the boiler flue of a power plant in the related art, there is less flue gas circulation on both sides of the heat exchange tube of the low-temperature economizer, resulting in dust accumulation and wear, and the elbow in the flue is close to the economizer, the flue gas diffusion distance is insufficient, the flue elbow is seriously dusty, and the flow field in the flue is turbulent. The fly ash particles carried by the flue gas continuously flush the heat exchange tube of the low-temperature economizer at a high flow rate, which will cause the heat exchange tube to leak. The leaked condensed water enters the flue, and the viscosity of the fly ash in the flue gas increases, resulting in sticky ash blockage. At the same time, after the water enters the flue, the acidic substances in the flue gas dissolve to produce acid liquid, causing corrosion of the heat exchange tube and fin, aggravating wear and leakage, and further causing flow field turbulence, forming a vicious circle. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, an embodiment of the present invention provides a low-temperature economizer system, which can reduce ash blockage of the flue and wear of the economizer and increase the service life.

[0004] The low-temperature economizer system of the embodiment of the present invention includes: a flue, the flue having a vertical section and a horizontal section connected to the bottom end of the vertical section, the vertical section having a reducing section at one end adjacent to the horizontal section with a flow cross-section gradually decreasing; an economizer body, the economizer body being arranged in the vertical section; a flow guide assembly, the flow guide assembly including a first flow guide component, a second flow guide component and a third flow guide component, the first flow guide component being arranged in the reducing section and located downstream of the economizer body, the second flow guide component being located at the junction of the vertical section and the horizontal section, and the third flow guide component being located in the horizontal section.

[0005] In this embodiment, a first guide component is provided in the variable diameter section of the flue to guide the flue gas, which can reduce the vortex in the variable diameter section, make the airflow diffuse evenly, and make the airflow streamline distribution more regular. At the same time, a second guide component is provided at the junction of the vertical section and the horizontal section of the flue. By guiding the turning of the flue with the second guide component, the existence of dead zones at the turning of the flue can be reduced, which facilitates the diffusion of flue gas downstream and reduces ash accumulation at the turning of the flue. In addition, a third guide component is provided in the horizontal section to make the airflow distribution in the horizontal section more even, so that the airflow in each section of the flue can be evenly diffused, reducing the low-speed and high-speed areas of the airflow, that is, reducing the maximum flow rate, which is beneficial to improving the heat exchange efficiency, reducing the scouring and wear of the heat exchange tubes of the economizer body by smoke particles, and helping to increase the service life.

[0006] In this embodiment, the first guide component includes a plurality of first guide plates and a plurality of second guide plates, the plurality of first guide plates are spaced apart along the first direction, and the first guide plates extend along the second direction, the first direction and the second direction are arranged orthogonally, the plurality of second guide plates are located downstream of the first guide plates, and the plurality of second guide plates are spaced apart along the second direction, and the second guide plates extend along the first direction.

[0007] In this embodiment, the second guide component includes a plurality of third guide plates, which are spaced apart from each other, and the third guide plates have a first end and a second end, the first end is adjacent to the vertical segment, the second end is adjacent to the horizontal segment, and the third guide plates extend along a first direction.

[0008] In this embodiment, the flue also includes an arc-shaped transition section arranged between the vertical section and the horizontal section, a plurality of the third guide plates are arranged in the arc-shaped transition section and distributed at radial intervals along the arc-shaped transition section, and the third guide plates are arc-shaped plates concentric with the arc-shaped transition section.

[0009] In this embodiment, the third guide component includes a plurality of fourth guide plates, the plurality of fourth guide plates are arranged at intervals along the first direction, and the fourth guide plates extend along a third direction, and the third direction is arranged orthogonally to the first direction.

[0010] In this embodiment, the flue also includes an outlet section, which is connected to one end of the horizontal section away from the vertical section, and the outlet section is arranged at an angle to the horizontal section. The low-temperature economizer system also includes a fourth flow guide component, and the fourth flow guide component is arranged in the outlet section.

[0011] In this embodiment, the plurality of fourth guide components include a plurality of fifth guide plates, and the plurality of fifth guide plates are spaced apart in the outlet section, and the fifth guide plates have a third end and a fourth end, the third end is adjacent to the horizontal section, and the fourth end is away from the horizontal section.

[0012] In this embodiment, the economizer body includes a plurality of heat exchange modules, which are arranged in sequence on the windward surface of the flue and stacked in the direction of flue gas flow in the flue. The heat exchange modules include heat exchange tubes and valves arranged on the heat exchange tubes, and the valves are used to control the flow of the medium in the heat exchange tubes. The circumferential surface of the heat exchange tubes is provided with open-toothed spiral fins.

[0013] In this embodiment, the heat exchange tube has a fixed end and a movable end, the fixed end is sealed and welded to the outer wall of the flue, and the movable end is sealed and connected to the outer wall of the flue via an elastic sealing member.

[0014] In this embodiment, the low-temperature economizer system further includes a temperature monitoring component, and the temperature monitoring component is disposed in the flue at the middle section corresponding to the economizer body and at the downstream end of the economizer body. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a low-temperature economizer system according to an embodiment of the present invention.

[0016] Figure 2 It is a structural schematic diagram of a guide assembly from a first perspective according to an embodiment of the present invention.

[0017] Figure 3 It is a structural schematic diagram of the guide component from a second viewing angle according to an embodiment of the present invention.

[0018] Figure 4 It is a structural schematic diagram of the guide component of an embodiment of the present invention from a third viewing angle.

[0019] Figure 5 It is a schematic diagram of the partial structure of the elastic seal and the heat exchange tube according to an embodiment of the present invention.

[0020] Reference numerals:

[0021] 1. Flue; 11. Vertical section; 111. Inlet pipe section; 12. Horizontal section; 13. Arc-shaped transition section; 14. Outlet section; 2. Economizer body; 21. Heat exchange tube; 22. Elastic seal; 3. Guide assembly; 31. First guide component; 311. First guide plate; 3111. Upper end plate; 3112. Lower end plate; 312. Second guide plate; 32. Second guide component; 33. Third guide component; 34. Fourth guide component. DETAILED DESCRIPTION

[0022] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0023] In this embodiment, if Figure 1 and Figure 2As shown in the figure, the X direction is the first direction, the Y direction is the second direction, and the Z direction is the third direction. The low-temperature economizer system includes a flue 1, an economizer body 2, and a guide assembly 3. The flue 1 has a vertical section 11 and a horizontal section 12 connected to the bottom end of the vertical section 11. The end of the vertical section 11 adjacent to the horizontal section 12 has a reducing section with a gradually decreasing flow cross-section. The economizer body 2 is arranged in the vertical section 11. The guide assembly 3 includes a first guide component 31, a second guide component 32, and a third guide component 33. The first guide component 31 is arranged in the reducing section and is located downstream of the economizer body 2. The second guide component 32 is located at the junction of the vertical section 11 and the horizontal section 12. The third guide component 33 is located in the horizontal section 12.

[0024] like Figure 1 and Figure 2 In the flue 1 shown, the vertical section 11 of the flue 1 has two inlet pipe sections 111, and the two inlet pipe sections 111 intersect at the downstream, and the flue gas enters the flue 1 from the two inlet pipe sections 111 respectively and is discharged through the flue 1 at the same time after merging. In order to allow more flue gas to enter the flue 1 when the flue 1 begins to merge, the flow cross-section of the flue 1 is larger, and the economizer body 2 is arranged at the intersection of the two inlet pipe sections 111 to cool the flue gas. The reducer is located downstream of the economizer body 2. After the economizer body 2 cools the flue gas, the flue gas volume is reduced, and the flow cross-section of the flue 1 is gradually reduced, which can save space while meeting the smoke exhaust requirements.

[0025] In this embodiment, a first guide component 31 is provided in the variable diameter section of the flue 1 to guide the flue gas, so that the vortex in the variable diameter section can be reduced, the airflow can be evenly diffused, and the airflow streamline distribution is more regular. At the same time, a second guide component 32 is provided at the intersection of the vertical section 11 and the horizontal section 12 of the flue 1. The second guide component 32 is used to guide the turning part of the flue 1, which can reduce the existence of dead zones at the turning parts of the flue 1, facilitate the diffusion of flue gas downstream, and reduce dust accumulation at the turning parts of the flue 1. In addition, a third guide component 33 is provided in the horizontal section 12 to make the airflow distribution in the horizontal section 12 more uniform, so that the airflow in each section of the flue 1 can be evenly diffused, reducing the low-speed area and the high-speed area of ​​the airflow, that is, reducing the maximum flow rate, which is beneficial to improving the heat exchange efficiency, reducing the scouring and wear of smoke particles on the heat exchange tubes 21 of the economizer body 2, and helping to increase the service life.

[0026] In this embodiment, if Figures 2 to 4 As shown, the first guide component 31 includes a plurality of first guide plates 311 and a plurality of second guide plates 312, the plurality of first guide plates 311 are spaced apart along the first direction, and the first guide plates 311 extend along the second direction, the first direction and the second direction are arranged orthogonally, the plurality of second guide plates 312 are located downstream of the first guide plates 311, and the plurality of second guide plates 312 are spaced apart along the second direction, and the second guide plates 312 extend along the first direction.

[0027] For example, the first guide plate 311 has an upper end plate 3111 and a lower end plate 3112, and the upper end plate 3111 and the lower end plate 3112 are arranged at an angle, and a guide channel is formed between two adjacent first guide plates 311, and the upper end plate 3111 receives the upstream smoke and guides the smoke, and the airflow is more smoothly transported downstream under the guiding effect of the two adjacent lower end plates 3112. The angle between the upper end plate 3111 and the lower end plate 3112 of each first guide plate 311, the length of the upper end plate 3111 and the lower end plate 3112, and the inclination angle of the upper end plate 3111 and the lower end plate 3112 can be adjusted as needed. In addition, the arrangement direction of the plurality of first guide plates 311 can also be adjusted as needed, which is not limited here.

[0028] Specifically, the first guide plate 311 and the second guide plate 312 can be connected to the inner wall of the flue 1 through an angle steel, one end of the angle steel is connected to the first guide plate 311 or the second guide plate 312, and the other end is connected to the inner wall of the flue 1. The angle steel is provided to facilitate the connection between the first guide plate 311 or the second guide plate 312 and the inner wall of the flue 1. The angle steel and the inner wall of the flue 1 and the first guide plate 311 or the second guide plate 312 can be welded or connected in other ways, which are not limited here.

[0029] It can be understood that by arranging a plurality of first guide plates 311 at intervals along the first direction and arranging a plurality of second guide plates 312 at intervals along the second direction, the airflow is guided through the guide channels formed by the plurality of first guide plates 311 and then guided through the guide channels formed by the plurality of second guide plates 312. The plurality of first guide plates 311 and the plurality of second guide plates 312 form a plurality of grid-like guide channels in the flow direction of the airflow, so that the airflow can be transported more evenly downstream.

[0030] In this embodiment, if Figures 2 to 4 As shown, the second guide component 32 includes a plurality of third guide plates, which are distributed at intervals, and each third guide plate has a first end and a second end, wherein the first end is adjacent to the vertical section 11 and the second end is adjacent to the horizontal section 12, and the third guide plates extend along the first direction.

[0031] Specifically, the third guide plate is connected to the flue 1 through an angle steel, which is the same as the connection method between the first guide plate 311 and the second guide plate 312. One end of the angle steel is connected to the third guide plate, and the other end is connected to the inner wall of the flue 1. The angle steel is provided to facilitate the connection between the third guide plate and the inner wall of the flue 1.

[0032] It is understandable that the airflow is prone to form a dead zone at the bend of the flue 1, that is, an area where only a small amount of airflow passes. The dead zone is prone to dust accumulation, which causes airflow turbulence, is not conducive to the diffusion of airflow, and the flue gas flow velocity deviation is large. The dust particles in the flue gas will wash the heat exchange tubes 21 of the economizer body 2, aggravating the wear of the heat exchange tubes 21. By arranging a third guide plate at the bend of the flue 1 for diversion, the airflow in the vertical section 11 can pass through the bend of the flue 1 evenly and enter the horizontal section 12, thereby improving the overall safety and economy.

[0033] In this embodiment, if Figures 2 to 4 As shown, the flue 1 also includes an arc-shaped transition section 13 arranged between the vertical section 11 and the horizontal section 12, and a plurality of third guide plates are arranged in the arc-shaped transition section 13 and distributed at radial intervals along the arc-shaped transition section 13. The third guide plates are arc-shaped plates concentric with the arc-shaped transition section 13.

[0034] It can be understood that by providing an arc-shaped turning section between the vertical section 11 and the horizontal section 12, the resistance of the inner wall of the flue 1 to the airflow can be reduced, thereby allowing the airflow to be more smoothly transported downstream. By providing the third guide plate as an arc-shaped plate concentric with the arc-shaped transition section 13, a plurality of arc-shaped guide channels can be formed in the arc-shaped turning section, which can make the airflow more evenly dispersed and reduce the airflow resistance.

[0035] In this embodiment, if Figures 2 to 4 As shown, the third guide component 33 includes a plurality of fourth guide plates, which are arranged at intervals along the first direction, and the fourth guide plates extend along a third direction, which is arranged orthogonal to the first direction.

[0036] It can be understood that by providing a plurality of fourth guide plates in the horizontal section 12, the airflow in the horizontal section 12 is guided, which is beneficial for the airflow in the horizontal section 12 to fill the flue 1 and further make the airflow distribution more regular.

[0037] In this embodiment, if Figures 2 to 4 As shown, the flue 1 also includes an outlet section 14, which is connected to one end of the horizontal section 12 away from the vertical section 11, and the outlet section 14 is arranged at an angle with the horizontal section 12. The low-temperature economizer system also includes a fourth flow guide component 34, which is arranged in the outlet section 14.

[0038] It should be noted that when the horizontal section 12 of the flue 1 needs to be connected to other pipes that are at an angle to the horizontal section 12, the flue 1 is connected to the other pipes through the outlet section 14, and a fourth guide component 34 is provided in the outlet section 14 to guide the flue gas, which is conducive to making the airflow distribution more uniform.

[0039] In this embodiment, if Figures 2 to 4As shown, the plurality of fourth guide components 34 include a plurality of fifth guide plates, which are spaced apart at the outlet section 14 , and each of the fifth guide plates has a third end and a fourth end, wherein the third end is adjacent to the horizontal section 12 , and the fourth end is away from the horizontal section 12 .

[0040] Specifically, the fifth guide plate is an arc-shaped plate, and the curvature of the fifth guide plate matches the angle between the horizontal section 12 and the outlet section 14, which is conducive to making the airflow flow more smoothly and evenly through the outlet section 14, thereby making the airflow field more uniform. The number of the fifth guide plates can be adjusted according to actual needs and is not limited here.

[0041] In this embodiment, the economizer body 2 includes a plurality of heat exchange modules, which are arranged in sequence on the windward side of the flue 1 and stacked in the flue 1 in the direction of flue gas flow. The heat exchange modules include a heat exchange tube 21 and a valve arranged on the heat exchange tube 21. The valve is used to control the flow of the medium in the heat exchange tube 21. The circumferential surface of the heat exchange tube 21 is provided with open-toothed spiral fins (not shown in the figure).

[0042] Specifically, the number of heat exchange modules arranged on the windward side of the flue 1 can be adaptively arranged according to the flow cross-sectional area of ​​the flue 1, and therefore, the specific number of heat exchange modules is not limited here. In addition, the installation method of the heat exchange module is a conventional prior art and is not described in detail here. The specific arrangement method of the open-tooth spiral fin is a conventional prior art and is not limited here.

[0043] In this embodiment, toothed spiral fins are provided on the circumferential surface of the heat exchange tube 21. Due to the toothed structure of the toothed spiral fins, dust is not easily deposited on the fin surface at a certain air flow velocity, thereby ensuring the heat exchange efficiency of the heat exchange tube 21. The toothed spiral fins destroy the boundary layer of the flue gas fluid on the tube wall, increase the turbulence near the tube wall, and strengthen the heat exchange between the flue gas and the tube wall.

[0044] In this embodiment, the heat exchange tube 21 has a fixed end and a movable end, and the fixed end is sealed and welded to the outer wall of the flue 1. Figure 5 As shown, the movable end is sealed and connected to the outer wall of the flue 1 via an elastic sealing member 22 .

[0045] Specifically, the fixed end of the heat exchange tube 21 is the end adjacent to the header, and the movable end is the end away from the header. The elastic seal 22 includes a first sealing section, a second sealing section and a third sealing section, which are sequentially arranged. The inner diameters of the first sealing section, the second sealing section and the third sealing section are the same, so that the elastic seal 22 can be sleeved on the outer circumference of the heat exchange tube 21. The outer diameter of the second sealing section is smaller than the outer diameter of the first sealing section, and the outer circumference of the second sealing section is conical. The outer circumference of the third sealing section is conical, and the outer diameter of the third sealing section is larger than the maximum outer diameter of the second sealing section. The maximum outer diameter end of the third sealing section is adjacent to the minimum outer diameter end of the second sealing section. The elastic seal 22 is elastic. By setting a conical outer circumference on the outer circumference of the elastic seal 22, it is convenient to insert the elastic seal 22 into the installation hole of the heat exchange tube 21 on the outer wall of the flue 1. After the elastic seal 22 is installed, the first sealing section and the third sealing section are respectively abutted against the outer wall and the inner wall of the flue 1. In order to achieve a better sealing effect, a high temperature resistant sealant is filled between the elastic sealing member 22 and the outer wall of the flue 1 and the heat exchange tube 21 to improve the sealing effect.

[0046] It can be understood that the fixed end of the heat exchange tube 21 is sealed and welded to the outer wall of the flue 1 to ensure the sealing effect of the fixed end, and the movable end of the heat exchange tube 21 is sealed and connected to the flue 1 by an elastic seal 22. While achieving sealing, the heat exchange tube 21 can also have a certain amount of moving space to withstand the stress during thermal expansion and contraction.

[0047] In this embodiment, the low-temperature economizer system further includes a temperature monitoring component (not shown in the figure), and temperature monitoring components are provided in the middle of the economizer body 2 and the downstream end of the economizer body 2 in the flue 1.

[0048] For example, the temperature monitoring element includes a thermal resistor, through which the temperature is measured, and the sensitivity can be continuously measured, so as to monitor the temperature in the flue 1 in real time. The working principle and connection method of the thermal resistor are conventional prior art and are not limited here.

[0049] A plurality of temperature monitoring components can be arranged at intervals in the middle of the economizer body 2 and downstream of the economizer body 2 to detect the temperature at different positions and improve the detection range. The specific number of temperature monitoring components can be set according to actual needs and is not limited here.

[0050] It is understandable that by providing a corresponding temperature detection component in the flue 1, it is convenient to monitor the temperature around the economizer body 2, so as to promptly remind the staff to make adjustments when the temperature is abnormal.

[0051] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0052] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0053] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0054] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0055] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0056] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A low temperature economizer system, characterized in that: include: A flue, the flue comprising a vertical section and a horizontal section connected to the bottom end of the vertical section, and one end of the vertical section adjacent to the horizontal section comprises a diameter-reducing section with a gradually decreasing flow cross section; an economizer body, the economizer body being arranged in the vertical section; The flow guide assembly includes a first flow guide component, a second flow guide component and a third flow guide component, the first flow guide component is arranged in the variable diameter section and is located downstream of the economizer body, the second flow guide component is located at the intersection of the vertical section and the horizontal section, and the third flow guide component is located in the horizontal section.

2. The low temperature economizer system according to claim 1, characterized in that: The first guide component includes a plurality of first guide plates and a plurality of second guide plates, the plurality of first guide plates are spaced apart along a first direction, and the first guide plates extend along a second direction, the first direction and the second direction are arranged orthogonally, the plurality of second guide plates are located downstream of the first guide plates, and the plurality of second guide plates are spaced apart along the second direction, and the second guide plates extend along the first direction.

3. The low temperature economizer system according to claim 1, characterized in that: The second guide component includes a plurality of third guide plates, which are spaced apart and have a first end and a second end. The first end is adjacent to the vertical section, the second end is adjacent to the horizontal section, and the third guide plates extend along a first direction.

4. The low temperature economizer system according to claim 3, characterized in that: The flue also includes an arc-shaped transition section arranged between the vertical section and the horizontal section. A plurality of third guide plates are arranged in the arc-shaped transition section and distributed at radial intervals along the arc-shaped transition section. The third guide plates are arc-shaped plates concentric with the arc-shaped transition section.

5. The low temperature economizer system according to claim 1, characterized in that: The third guide component includes a plurality of fourth guide plates, the plurality of fourth guide plates are arranged at intervals along the first direction, and the fourth guide plates extend along a third direction, and the third direction is arranged orthogonally to the first direction.

6. The low temperature economizer system according to claim 1, characterized in that: The flue further includes an outlet section, which is connected to one end of the horizontal section away from the vertical section, and the outlet section is arranged at an angle with the horizontal section. The low-temperature economizer system further includes a fourth flow guide component, and the fourth flow guide component is arranged in the outlet section.

7. The low temperature economizer system according to claim 6, characterized in that: The plurality of fourth guide components include a plurality of fifth guide plates, which are spaced apart at the outlet section, and the fifth guide plates have a third end and a fourth end, wherein the third end is adjacent to the horizontal section, and the fourth end is away from the horizontal section.

8. The low temperature economizer system according to claim 7, characterized in that: The economizer body includes a plurality of heat exchange modules, which are arranged in sequence on the windward surface of the flue and stacked in the direction of flue gas flow in the flue. The heat exchange modules include heat exchange tubes and valves arranged on the heat exchange tubes, and the valves are used to control the flow of the medium in the heat exchange tubes. The circumferential surface of the heat exchange tubes is provided with open-toothed spiral fins.

9. The low temperature economizer system according to claim 8, characterized in that: The heat exchange tube has a fixed end and a movable end. The fixed end is sealed and welded to the outer wall of the flue, and the movable end is sealed and connected to the outer wall of the flue via an elastic sealing member.

10. The low temperature economizer system according to any one of claims 1 to 9, characterized in that: It also includes a temperature monitoring component, which is arranged in the flue at the middle section corresponding to the economizer body and the downstream end of the economizer body.

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