A low-temperature economizer anti-condensation device of waste heat recovery type

Abstract

This invention discloses a waste heat recovery type low-temperature economizer anti-condensation device. The device uses a high-sensitivity water temperature sensor installed at the outlet of the heat exchanger bend and a liquid valve installed at the inlet, electrically connected to form a closed-loop temperature control system. During operation, the water temperature sensor collects the outlet water temperature data in real time; when the detected temperature approaches the critical value of the flue gas acid dew point, the system automatically drives the liquid valve to precisely adjust the cooling medium flow rate. This active adjustment mechanism ensures that the pipe wall temperature is always within a safe range, avoiding both condensation corrosion caused by excessively low temperatures and reduced waste heat recovery efficiency due to excessively high temperatures. Compared with traditional technologies, this solution requires no frequent manual intervention, fundamentally solving the low-temperature corrosion problem by precisely controlling the internal fluid temperature, ensuring stable operation of the equipment under optimal conditions, and significantly improving energy utilization and equipment lifespan.

Description

Technical Field

[0001] This invention belongs to the technical field of boiler economizers and relates to a waste heat recovery type low temperature economizer anti-condensation device. Background Technology

[0002] Against the backdrop of current energy structure optimization and energy conservation and emission reduction, boilers, as core thermal energy equipment in the industrial sector, have received considerable attention for their operational efficiency. Economizers, as important auxiliary devices at the boiler's tail end, play a crucial role in improving the overall thermal efficiency of the boiler by recovering waste heat from flue gas to heat feedwater. However, in actual operation, especially in hot water boiler systems, the return water temperature is often far below the rated design value, causing the economizer tube wall temperature to easily drop below the flue gas dew point temperature, leading to serious engineering challenges.

[0003] To address this challenge, existing technological research has made some progress. For example, patent CN206944489U proposes an external anti-condensation device for boiler economizers. This device attempts to solve the condensation problem by controlling the water flow and regulating the temperature through the installation of economizer pipes on the inner wall of the top of the frame, along with components such as a water inlet header, a water outlet header, and an electric ball valve. Although existing technologies have made breakthroughs in anti-condensation control, their structural defects and functional limitations have gradually become apparent in practical applications, failing to meet the requirements of long-term high-efficiency operation. Specifically, while existing devices can prevent condensation on the inner wall of the economizer pipes, the heat exchange fins on the economizer assembly are located inside the economizer pipes, forming a completely enclosed structure. This design creates a critical maintenance blind spot. Since the heat exchange fins are in the flue gas passage for a long time, a lot of dust and fly ash will inevitably adhere to their surface. The closed structure makes it impossible to effectively clean this dust. The accumulated dust will significantly increase the thermal resistance, reduce the heat exchange efficiency of the heat exchange fins, and thus offset the energy-saving benefits brought by the anti-condensation technology. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a waste heat recovery type low-temperature economizer anti-condensation device, thereby solving the technical problem that although the prior art can achieve anti-condensation by adjusting the water temperature, its integrated closed structure makes it impossible to clean the internal heat exchange fins after ash accumulation, and long-term operation will reduce the heat exchange efficiency due to the increased thermal resistance caused by ash accumulation.

[0005] This invention is achieved through the following technical solution: A waste heat recovery type low-temperature economizer anti-condensation device includes an economizer pipe with a flue gas inlet at one end and a flue gas outlet at the other end, and an internal heat exchange bend. The heat exchange bend includes a water inlet and an outlet, both extending to the outside of the economizer pipe. The heat exchange bend has several heat exchange fins. A liquid valve is installed at the water inlet, and a water temperature sensor is installed at the water outlet. The water temperature sensor is electrically connected to the liquid valve and is used to adjust the water inflow based on the outlet water temperature.

[0006] Optionally, the heat exchange fins are evenly spaced.

[0007] Optionally, the economizer pipeline includes a top plate and a bottom plate; both the top plate and the bottom plate are detachably connected to the economizer pipeline.

[0008] Optionally, the top plate is detachably connected to the economizer pipe by bolts.

[0009] Optionally, the base plate is detachably connected to the economizer pipe by bolts.

[0010] Optionally, a sealing gasket is provided between the top plate and the bottom plate and the economizer pipe.

[0011] Optionally, support legs are symmetrically fixed on both sides of the economizer pipe.

[0012] Optionally, both the flue gas inlet and the flue gas outlet are provided with flange structures for connecting to the flue.

[0013] Optionally, the heat exchange bend can be a serpentine coil structure or a U-shaped bend structure.

[0014] Optionally, the heat exchange fins are any one of spiral fins, H-shaped fins, or longitudinal fins that are sleeved and fixed on the outer wall of the heat exchange bend.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a waste heat recovery type low-temperature economizer anti-condensation device. This device uses a high-sensitivity water temperature sensor installed at the outlet of the heat exchange bend inside the economizer pipes and a liquid valve installed at the inlet, electrically connecting the two. This allows for dynamic monitoring and real-time response to the heat exchange status. During operation, the water temperature sensor collects real-time data on the outlet water temperature of the medium inside the pipes. When the detected temperature fluctuation approaches the acid dew point critical value of the flue gas, the system automatically activates the liquid valve to precisely adjust the flow rate of the cooling medium entering the heat exchange bend. This active adjustment mechanism ensures that the heat exchange tube wall temperature is always maintained within a safe range, preventing corrosion of the equipment due to excessively low tube wall temperature and reducing waste heat recovery efficiency due to excessively high temperature. Compared to traditional technologies, this solution requires no frequent manual intervention. Through precise control of the internal fluid temperature, it fundamentally solves the problem of low-temperature corrosion, while ensuring long-term stable operation of the economizer under optimal conditions, significantly improving energy utilization and equipment lifespan.

[0016] Furthermore, the heat exchange fins are evenly spaced, ensuring the stability of the flue gas flow field and allowing for sufficient and balanced heat exchange between the high-temperature flue gas and the fin surface. This effectively avoids a surge in airflow resistance or the formation of heat exchange dead zones due to excessively dense local fins. Simultaneously, a reasonable and uniform spacing helps reduce the risk of ash accumulation caused by eddies, balancing fluid flowability and anti-clogging performance, thereby improving the overall heat transfer coefficient while extending the maintenance cycle of the device.

[0017] Furthermore, the economizer pipeline includes a top plate and a bottom plate; both the top plate and the bottom plate are detachably installed from the economizer pipeline, adopting a modular design with separate upper and lower sections, breaking the closed limitations of traditional integrated equipment. When the equipment needs maintenance, cleaning of accumulated ash, or replacement of damaged components, there is no need to destructively disassemble the entire pipeline, greatly improving the maintainability and ease of operation of the equipment in the later stages.

[0018] Furthermore, the top plate and the bottom plate are detachably connected to the economizer piping via bolts. Bolting is a mature, reliable, and efficient mechanical fixing method. It not only provides sufficient fastening force to withstand the internal pressure during equipment operation but also makes the disassembly and assembly process extremely simple and quick. Maintenance personnel only need conventional tools to complete the separation and installation of the top and bottom plates, significantly reducing the labor and time costs of on-site maintenance.

[0019] Furthermore, sealing gaskets are provided between the top plate and the bottom plate and the economizer pipe, and the bottom plate is detachably connected to the economizer pipe by bolts. Furthermore, symmetrical support legs are fixedly installed on both sides of the economizer pipeline. These symmetrically installed support legs provide stable physical support for the entire economizer device, capable of bearing the weight of the pipeline itself, the internal medium, and external loads, effectively preventing the equipment from sinking, tilting, or breaking. At the same time, this support structure facilitates the overhead installation of the equipment, which is beneficial for ventilation of the bottom space and the connection and layout of subsequent pipelines.

[0020] Furthermore, both the flue gas inlet and outlet are equipped with flange structures for connecting to the flue. These standardized flange structures significantly improve the compatibility and connection efficiency of the device with existing boiler flue systems. This allows for more precise installation and positioning, a more secure connection, and also facilitates future relocation or overhaul of the device from the flue system.

[0021] Furthermore, the heat exchange bend is a serpentine coil structure or a U-shaped bend structure. The curved pipe design significantly extends the flow path and residence time of water inside the economizer, greatly improving the heat exchange efficiency between the flue gas and the medium inside the pipe. In addition, this geometric shape can effectively absorb the thermal expansion stress generated by the equipment during long-term alternating hot and cold operation by utilizing its own flexibility, enhancing the stability and safety of the overall structure.

[0022] Furthermore, the heat exchange fins can be any one of spiral fins, H-shaped fins, or longitudinal fins, which are sleeved and fixed to the outer wall of the heat exchange bend. This variety of fin types provides flexible options to adapt to different operating conditions. For example, H-shaped fins can effectively separate flue gas flow channels and reduce dead ash deposition; spiral fins can disrupt the fluid boundary layer to enhance turbulence. By selecting specific types of fins, the wear resistance and self-cleaning capabilities of the equipment can be specifically optimized while ensuring efficient recovery of flue gas waste heat. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a top view schematic diagram of an anti-condensation device for a waste heat recovery type low-temperature economizer according to the present invention; Figure 2 This is a bottom view of the anti-condensation device for a waste heat recovery type low-temperature economizer in this invention. Figure 3 This is a schematic diagram of the internal structure of an anti-condensation device for a waste heat recovery type low-temperature economizer in this invention.

[0025] The components include: 1. Economizer piping; 11. Flue gas inlet; 12. Flue gas outlet; 13. Support leg; 2. Heat exchanger bend; 21. Water inlet; 22. Water outlet; 3. Liquid valve; 4. Water temperature sensor; 5. Top plate; 6. Bottom plate; 7. Bolts; 8. Heat exchanger fins; 9. Sealing gasket. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0028] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0029] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention 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, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0030] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0031] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0032] The present invention will now be described in further detail with reference to the accompanying drawings: like Figures 1-3 As shown, this invention discloses a waste heat recovery type low-temperature economizer anti-condensation device. The device includes an economizer pipe 1, with a flue gas inlet 11 at one end and a flue gas outlet 12 at the other end. The economizer pipe 1 has an internal heat exchange bend 2. The heat exchange bend 2 includes a water inlet 21 and a water outlet 22, both extending to the outside of the economizer pipe 1. The heat exchange bend 2 has several heat exchange fins 8. A liquid valve 3 is installed at the water inlet 21, and a water temperature sensor 4 is installed at the water outlet 22. The water temperature sensor 4 is electrically connected to the liquid valve 3 and is used to adjust the water inflow according to the outlet water temperature.

[0033] This invention discloses a waste heat recovery type low-temperature economizer anti-condensation device, the core of which lies in constructing an active temperature control circulation system based on real-time water temperature feedback. The main body of the device consists of an economizer pipe 1 with a flue gas inlet 11 and an exhaust port 12 at both ends. Several heat exchange bends 2 with heat exchange fins 8 are installed inside the pipe to maximize the gas-liquid heat exchange area. In terms of control logic, the device integrates a water temperature sensor 4 at the outlet 22 of the heat exchange bends and a liquid valve 3 at the inlet 21. The two are electrically connected to form a closed-loop feedback circuit. When the device is running, the water temperature sensor 4 monitors the temperature of the medium flowing through the heat exchange bend in real time and feeds the signal back to the control system, which in turn drives the liquid valve 3 to automatically adjust the water inflow: when the water temperature is detected to be too low and the pipe wall temperature is close to the flue gas dew point, the system controls the liquid valve to reduce the opening and reduce the flow rate to prolong the heat absorption time of the medium, thereby increasing the wall temperature to prevent condensation and corrosion; conversely, it increases the opening to enhance waste heat recovery, thus achieving a dynamic balance between efficient heat exchange and corrosion protection.

[0034] Furthermore, such as Figure 3As shown, the heat exchange fins 8 are evenly spaced; that is, to further optimize heat exchange efficiency and ensure the stability of equipment operation, the heat exchange fins 8 are evenly arrayed along the axial direction of the heat exchange bend. This uniform layout not only ensures a consistent heat dissipation area distribution in both the circumferential and axial directions of the heat exchange bend, allowing the high-temperature flue gas to fully and uniformly exchange heat with the fin surface when flowing through the economizer pipe, effectively avoiding the surge in airflow resistance or heat exchange dead zones caused by excessively dense fins in some areas, as well as insufficient heat recovery caused by excessively sparse fins in others; at the same time, the uniform and reasonable fin spacing helps maintain the stability of the flue gas flow field, reduces the risk of ash accumulation caused by eddies or turbulence, and ensures that heat is evenly dissipated on the radiator surface and surrounding space, thereby improving the overall heat transfer coefficient while taking into account fluid flowability and anti-clogging performance, and extending the maintenance cycle of the device.

[0035] Furthermore, such as Figures 1-2 As shown, the economizer pipe 1 includes a top plate 5 and a bottom plate 6, both of which are detachably connected to the economizer pipe 1. In a specific embodiment, both the top plate 5 and the bottom plate 6 are detachably connected to the economizer pipe 1 by bolts 7. A sealing gasket 9 is provided between the top plate 5 and the bottom plate 6 and the economizer pipe 1.

[0036] In order to effectively solve the technical problem of difficult cleaning of ash accumulation on the heat exchange fins inside traditional integrated economizers, which leads to a decrease in heat exchange efficiency over time, this embodiment adopts a modular design for the overall structure of the economizer pipe 1. Specifically, the top and bottom of the economizer pipe 1 are respectively provided with a detachable and fixed top plate 5 and a bottom plate 6. This split structure design breaks the closed limitation of traditional equipment and greatly improves the maintainability of the equipment in the later stage. In actual assembly and sealing, the top plate 5 is firmly fixed to the top of the economizer pipe 1 by several high-strength bolts 7, and the bottom plate 6 is also fixed to the bottom of the pipe by bolts 7. Considering that there is a certain pressure fluctuation in the flue gas flow in the boiler tail flue, in order to prevent high temperature or corrosive flue gas from leaking out from the connection gaps, thereby causing environmental pollution or unnecessary heat loss, special sealing gaskets 9 are precisely embedded between the contact surfaces of the top plate 5 and the economizer pipe 1, and between the contact surfaces of the bottom plate 6 and the economizer pipe 1. These gaskets 9 are typically made of high-temperature resistant, corrosion-resistant composite materials with good resilience. When the bolts 7 are tightened, the gaskets 9 undergo slight elastic deformation under the strong tightening force, thus tightly filling the microscopic gaps in the flange connection surface and ensuring the excellent airtightness of the entire device during long-term operation. In actual inspection and maintenance scenarios, when a large amount of dust or adhesive is found on the surface of the heat exchange fins 8 inside the economizer, leading to increased system thermal resistance and decreased heat exchange performance, maintenance personnel do not need to perform destructive disassembly of the entire equipment. They can easily separate and remove the top plate and bottom plate from the economizer pipe 1 simply by loosening and removing the bolts 7 that fix the top plate 5 and bottom plate 6. This convenient disassembly method directly exposes the internal space of the economizer pipe 1, allowing maintenance personnel to directly and comprehensively access the internal heat exchange fins 8, thus facilitating the thorough cleaning of the accumulated dust on the fin surface using a high-pressure air gun, brush, or other cleaning tools. This convenient maintenance, performed regularly or as needed, effectively restores the cleanliness and thermal conductivity of the heat exchange fins 8, ensuring that the economizer pipeline 1 is always in a state of efficient heat exchange. This not only significantly extends the service life of the equipment but also maximizes the recovery of waste heat from the flue gas, achieving the operational goals of energy conservation and emission reduction.

[0037] The heat exchange bend 2 is a serpentine coil structure or a U-shaped bend structure. The heat exchange fins 8 are any one of spiral fins, H-shaped fins, or longitudinal fins that are sleeved and fixed to the outer wall of the heat exchange bend 2. That is, in order to further optimize the heat exchange performance of the device and adapt to different operating conditions, the heat exchange bend 2 is preferably designed as a serpentine coil structure or a U-shaped bend structure. This curved pipe design can not only significantly extend the flow path and residence time of water inside the economizer pipe 1, thereby greatly improving the heat exchange efficiency between flue gas and the medium inside the pipe, but also effectively absorb the thermal expansion stress generated by the equipment during long-term alternating hot and cold operation by utilizing its own geometric shape, thereby enhancing the stability and safety of the overall structure. On this basis, in order to further expand the heat-receiving area and enhance the heat transfer effect, several heat exchange fins 8 are tightly fixed to the outer wall of the heat exchange bend 2 by processes such as sleeve, welding, or rolling; specifically, these heat exchange fins 8 can be flexibly selected from any one of spiral fins, H-shaped fins, or longitudinal fins according to the actual requirements for preventing ash accumulation and flow resistance. For example, H-shaped fins can divide the flue gas space into multiple small areas, which can play a good role in equalizing the airflow and effectively reduce the deposition of dead ash in the vortex zone. Spiral fins can destroy the fluid boundary layer to enhance the degree of turbulence. By reasonably selecting the fin type, it is possible to ensure efficient recovery of flue gas waste heat while taking into account the wear resistance and self-cleaning ability of the equipment.

[0038] In one specific embodiment, support legs 13 are symmetrically fixed on both sides of the economizer pipe 1. Furthermore, flange structures for connecting the flue gas duct are provided at both the flue gas inlet 11 and the flue gas outlet 12.

[0039] The working principle of the waste heat recovery type low-temperature economizer anti-condensation device of the present invention is as follows: During use, high-temperature flue gas is introduced into the economizer pipe 1 through the flue gas inlet 11, and water is introduced into the heat exchange bend 2 through the water inlet 21. The high-temperature flue gas entering the economizer pipe 1 can undergo heat exchange on the surface of the heat exchange fins 8, and exchange heat with the water through the heat exchange fins 8 and the heat exchange bend 2, thus recovering the waste heat of the flue gas. The heated hot water flows out from the water outlet 22, and the water temperature can be detected by the water temperature sensor 4. Flue gas can be discharged from the flue gas exhaust port 12. When the water temperature sensor 4 detects… When the temperature drops below the set value, the liquid valve 3 can reduce the water flow rate into the heat exchanger bend 2. As the water flow rate inside the heat exchanger bend 2 decreases, the water temperature inside the heat exchanger bend 2 will rise, which will also raise the temperature inside the economizer pipe 1. This will prevent condensation from occurring on the inner wall of the economizer pipe 1 due to low temperature, and prevent dust accumulation and low-temperature corrosion. By unscrewing the bolt 7 and removing the top plate 5 and bottom plate 6 from the top and bottom of the economizer pipe 1 respectively, the dust and other debris adhering to the surface of the heat exchange fins 8 inside the economizer pipe 1 can be cleaned, ensuring efficient heat exchange of the heat exchange fins 8.

[0040] In the actual operation of the waste heat recovery type low-temperature economizer anti-condensation device of this invention, high-temperature flue gas is first smoothly introduced into the internal cavity of the economizer pipe 1 through the flue gas inlet 11. At the same time, boiler feedwater or circulating water is continuously injected into the heat exchange bend 2 through the water inlet 21. When the high-temperature flue gas flows through the economizer pipe 1, it will fully wash and wrap the densely distributed heat exchange fins 8. The heat is quickly transferred to the internally flowing cold water through the highly thermally conductive heat exchange fins 8 and the pipe wall of the heat exchange bend 2, thereby efficiently recovering the sensible heat and latent heat in the flue gas, completing the preheating of the water. The hot water after absorbing heat and heating up finally flows out from the water outlet 22 into the subsequent thermal system, while the low-temperature flue gas after releasing heat is discharged from the flue gas exhaust port 12. In this dynamic heat exchange process, the water temperature sensor 4 installed at the outlet 22 plays a crucial monitoring role. It can accurately collect the temperature data of the outflowing medium in real time and feed it back to the control system. Once the water temperature is detected to be lower than the preset safety threshold, it indicates that the pipe wall temperature is approaching or below the acid dew point temperature of the flue gas, which can easily lead to condensation corrosion. The control system will immediately issue a command to drive the liquid valve 3 to automatically reduce the water flow rate entering the heat exchange bend 2. As the water flow velocity in the pipe decreases, the residence time of the medium in the bend is extended, and the heat absorption is more complete. This causes the overall wall temperature of the heat exchange bend 2 and the heat exchange fins 8 in close contact with it to rise, keeping the metal wall temperature above the acid dew point of the flue gas. This fundamentally eliminates the generation of acidic condensate and effectively prevents fly ash adhesion and accumulation and low-temperature acid corrosion. In addition, when the equipment has been running for a long time and it is necessary to clean the stubborn dust attached to the surface of the heat exchange fins 8 in order to restore the heat exchange efficiency, the maintenance personnel only need to use tools to unscrew the fixing bolts 7, and can easily disassemble and separate the top plate 5 and the bottom plate 6 from the top and bottom of the economizer pipe 1 respectively, directly exposing the internal components. This allows for convenient and thorough physical removal of the accumulated dust on the surface of the heat exchange fins 8, ensuring that the device is always in the best efficient heat exchange state.

[0041] This invention discloses a waste heat recovery type low-temperature economizer anti-condensation structure. A water temperature sensor monitors the temperature of the water flowing out of the outlet, and a liquid valve regulates the amount of water entering the heat exchanger bend. This regulates the temperature of the inner wall of the economizer pipe, preventing condensation due to low inner wall temperature, thus preventing ash accumulation and low-temperature corrosion. Removable top and bottom plates are installed at the top and bottom of the economizer pipe, respectively, allowing for easy cleaning of dust from the heat exchange fins and ensuring efficient heat exchange inside the economizer pipe.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A waste heat recovery type low-temperature economizer anti-condensation device, characterized in that, The system includes an economizer pipe (1), one end of which is provided with a flue gas inlet (11) and the other end with a flue gas outlet (12). The economizer pipe (1) has an internal heat exchange bend (2). The heat exchange bend (2) includes a water inlet (21) and a water outlet (22), both of which extend to the outside of the economizer pipe 1. The heat exchange bend (2) is provided with several heat exchange fins (8). The water inlet (21) is provided with a liquid valve (3), and the water outlet (22) is provided with a water temperature sensor (4). The water temperature sensor (4) is electrically connected to the liquid valve (3) and is used to adjust the water inlet flow according to the water outlet temperature.

2. The anti-condensation device for a waste heat recovery type low-temperature economizer according to claim 1, characterized in that, Several heat exchange fins (8) are evenly spaced.

3. The anti-condensation device for a waste heat recovery type low-temperature economizer according to claim 1, characterized in that, The economizer pipe 1 includes a top plate (5) and a bottom plate (6); both the top plate (5) and the bottom plate (6) are detachably connected to the economizer pipe (1).

4. The anti-condensation device for a waste heat recovery type low-temperature economizer according to claim 3, characterized in that, The top plate (5) is detachably connected to the economizer pipe (1) by bolts (7).

5. The anti-condensation device for a waste heat recovery type low-temperature economizer according to claim 3, characterized in that, The base plate (6) is detachably connected to the economizer pipe (1) by bolts (7).

6. The anti-condensation device for a waste heat recovery type low-temperature economizer according to claim 3, characterized in that, Sealing gaskets (9) are provided between the top plate (5) and the bottom plate (6) and the economizer pipe (1).

7. The anti-condensation device for a waste heat recovery type low-temperature economizer according to claim 1, characterized in that, The economizer pipe (1) is symmetrically fixed with support legs (13) on both sides.

8. The anti-condensation device for a waste heat recovery type low-temperature economizer according to claim 1, characterized in that, Both the flue gas inlet (11) and the flue gas outlet (12) are provided with flange structures for connecting the flue.

9. The anti-condensation device for a waste heat recovery type low-temperature economizer according to claim 1, characterized in that, The heat exchange bend (2) is a serpentine coil structure or a U-shaped bend structure.

10. The anti-condensation device for a waste heat recovery type low-temperature economizer according to claim 1, characterized in that, The heat exchange fins (8) are any one of spiral fins, H-shaped fins or longitudinal fins that are sleeved and fixed on the outer wall of the heat exchange bend (2).

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