Double-layer full-sealing smoke collecting and heat exchanging device of aluminum alloy centralized melting furnace

Abstract

The application discloses a double-layer full-sealing smoke collecting and heat exchanging device of an aluminum alloy centralized melting furnace, and relates to the technical field of aluminum alloy melting equipment. The device comprises a double-layer sealing structure smoke collecting cover body, a water-cooling heat exchanging assembly arranged in a smoke flow channel, a fixed hot air heat exchanging assembly, a liftable movable hot air heat exchanging assembly, a lifting traction mechanism for driving the lifting of the movable assembly, and a double-path combustion-supporting air mixing system in communication with the hot air heat exchanging assembly. The smoke collecting cover body realizes smoke sealing collection and heat preservation, the water-cooling heat exchanging assembly and the fixed / movable hot air heat exchanging assembly are staggered, forming a double-medium heat exchanging structure, and the movable assembly is adjusted and adapted to different working conditions through lifting. The application solves the problems of poor smoke sealing, low heat exchanging efficiency and large combustion-supporting air temperature fluctuation of the existing device, has the advantages of high heat recycling rate, environmental protection and energy saving, stable operation and strong adaptability, and can significantly reduce the energy consumption and pollutant emission of the aluminum alloy melting furnace and improve the combustion efficiency and melting quality.

Description

Technical Field

[0001] This application relates to the technical field of aluminum alloy melting equipment, and in particular to a double-layer fully sealed smoke collection and heat exchange device for a centralized aluminum alloy melting furnace. Background Technology

[0002] Centralized aluminum alloy melting furnaces are core equipment in the aluminum processing industry. During their operation, they generate a large amount of high-temperature flue gas. If the large amount of sensible heat contained in the flue gas is directly discharged, it will not only cause serious energy waste, but also lead to problems such as increased ambient temperature and thermal pollution. At the same time, if the high-temperature flue gas is not collected completely and leaks occur, it will have an adverse impact on the workshop operating environment and the health of the operators.

[0003] In related technologies, a fume hood is typically installed at the flue gas exhaust port on the top of the aluminum alloy centralized melting furnace as a supporting component for flue gas collection. The basic structure of the fume hood is mostly a welded steel plate shell, with a flue gas inlet at the lower end connecting to the furnace exhaust position, and a flue gas outlet on the side wall or top. A hollow flow channel is formed inside the shell to collect the high-temperature flue gas generated by the melting furnace and guide it out through the exhaust outlet.

[0004] The problem with the relevant technology is that traditional flue gas hoods mostly use water-cooled heat exchange, or although they use a combination of water-cooled and air-cooled heat exchange, the heat exchange tube bundles are fixed and cannot be adjusted. They cannot adjust the heat exchange contact area according to different furnace capacities and different flue gas temperatures. The waste heat recovery and utilization rate of flue gas is generally less than 30%, and a large amount of flue gas is directly discharged into the air.

[0005] In addition, the combustion system of the melting furnace relies on preheating the combustion air to improve combustion efficiency. Traditional heat exchange structures heat the combustion air through a single path. Even small fluctuations in flue gas flow and temperature can cause a large deviation in the temperature of the combustion air, with a temperature difference of more than ±50℃, which cannot reach the actual required temperature of the combustion air in the melting furnace. Summary of the Invention

[0006] In order to fully recover and utilize the heat from the emitted flue gas, this application provides a double-layer fully sealed flue gas heat exchange device for a centralized aluminum alloy melting furnace.

[0007] The double-layer fully sealed flue gas heat exchange device for a centralized aluminum alloy melting furnace provided in this application adopts the following technical solution:

[0008] A double-layer fully sealed flue gas collection and heat exchange device for a centralized aluminum alloy melting furnace includes:

[0009] The fume hood is installed at the flue gas emission position of the aluminum alloy centralized melting furnace. It has a double-layer sealed box structure. The fume hood has a flue gas inlet at the lower end and a flue gas outlet on the upper side. The interior forms a flue gas flow channel for the flue gas to flow from bottom to top.

[0010] The water-cooled heat exchange component is integrally arranged inside the flue gas flow channel of the smoke collection hood, and the liquid inlet of the water-cooled heat exchange component is located on the side close to the flue gas outlet.

[0011] The fixed hot air heat exchanger is arranged in a plane perpendicular to the flue gas flow direction and is located in the area of ​​the water-cooled heat exchanger near the flue gas outlet.

[0012] A mobile hot air heat exchange component is located on the side of the fixed hot air heat exchange component near the flue gas inlet and is parallel to the plane of the fixed hot air heat exchange component. The mobile hot air heat exchange component can move up and down along the vertical flue gas flow direction to get closer to or away from the flue gas inlet.

[0013] A lifting and traction mechanism is installed on the smoke collection hood and is used to drive the mobile hot air heat exchange component to lift and lower.

[0014] A dual-path combustion air mixing system is installed on the outside of the smoke hood. Both the fixed hot air heat exchange component and the mobile hot air heat exchange component are connected to the dual-path combustion air mixing system. The air after heat exchange is mixed in the dual-path combustion air mixing system to form combustion air at the target temperature.

[0015] Optionally, the water-cooled heat exchange assembly includes multiple U-shaped heat exchange tubes arranged in a rectangular array, with the multiple U-shaped heat exchange tubes arranged in a rectangular array along the transverse and longitudinal directions of the smoke collection hood.

[0016] Both the fixed hot air heat exchanger and the mobile hot air heat exchanger are coil structures, with the coils and U-shaped heat exchange tubes interlaced and arranged.

[0017] Optionally, the inlet ends of all the U-shaped tubes are interconnected and connected to a water-cooled manifold inlet pipe, and the outlet ends of all the U-shaped tubes are interconnected and connected to a water-cooled manifold outlet pipe. The water-cooled manifold inlet pipe and the water-cooled manifold outlet pipe extend to the outside through the wall panel of the smoke collection hood.

[0018] The vertical height of the inlet end of each U-shaped tube is higher than that of the outlet end, and the flue gas outlet of the smoke collection hood is located above the outlet end of the U-shaped tube and corresponds to the flue gas outlet in the horizontal direction;

[0019] The fixed hot air heat exchanger is located in the space between the inlet and outlet ends of the U-shaped tube, close to the flue gas outlet.

[0020] Optionally, the lifting and traction mechanism includes a drive motor, a transmission screw, and a screw nut. The drive motor is installed on the top of the outer side of the smoke collection hood. The output shaft of the drive motor is coaxially fixed with the transmission screw. The screw nut is threaded onto the transmission screw. The movable hot air heat exchange component is connected to the screw nut so that it can be lifted and lowered in the vertical direction.

[0021] Optionally, the lifting and traction mechanism further includes a guide and limiting component, which includes multiple hollow guide rails evenly distributed on the inner side wall of the smoke collection hood, and the transmission screw and screw nut are both disposed inside the guide rails.

[0022] Each of the guide rails has a guide groove on the side facing the flue gas passage, and a guide slider is slidably installed in the guide groove. The guide slider is fixedly connected to the movable hot air heat exchange component, and the nut seat is fixedly connected to the guide slider.

[0023] Optionally, the dual-path combustion air mixing system includes a combustion air main pipe, a first heat exchange branch, and a second heat exchange branch. The outlet end of the fixed hot air heat exchange component is connected to the first heat exchange branch, and the outlet end of the mobile hot air heat exchange component is connected to the second heat exchange branch. Both the first heat exchange branch and the second heat exchange branch are connected to the combustion air main pipe.

[0024] Optionally, the double-layer sealed box structure of the smoke collection hood includes an inner smoke flow shell and an outer heat insulation and protection shell, wherein each wall panel of the inner smoke flow shell is sealed and connected to form a sealed cavity;

[0025] The space between the inner flue gas circulation shell and the outer thermal insulation protective shell is filled with thermal insulation material.

[0026] Optionally, a smoke exhaust pipe is sealed and installed on the outside of the smoke collection hood at the position corresponding to the smoke outlet, and a smoke exhaust control valve is installed in the middle section of the smoke exhaust pipe.

[0027] The side of the smoke collection hood opposite the smoke inlet is an inclined guide surface, and the side of the inclined guide surface away from the exhaust pipe is inclined towards the smoke inlet.

[0028] Optionally, the mobile hot air heat exchanger includes a coil body, with metal bellows expansion joints connected to both ends of the coil body. The metal bellows expansion joints pass through the wall panel of the smoke hood to form a medium inlet and a medium outlet, and the medium outlet is connected to a dual-path combustion air mixing system.

[0029] In summary, this application includes at least one of the following beneficial technical effects:

[0030] 1. By staggering the water-cooled heat exchange components with fixed and mobile hot air heat exchange components, synchronous heat exchange of dual media is achieved, increasing the heat exchange area by 40%-60% compared to single-media heat exchange devices. At the same time, the mobile hot air heat exchange components can be raised and lowered vertically, dynamically adjusting the distance from the flue gas inlet according to the flue gas temperature and flow rate, adapting to the heat exchange requirements under different operating conditions, increasing the heat recovery utilization rate to over 65%, and significantly reducing the energy consumption of the melting furnace.

[0031] 2. The dual-path combustion air mixing system combines the air heated by the fixed hot air heat exchange components and the mobile hot air heat exchange components, which can precisely control the temperature of the combustion air and avoid temperature fluctuations caused by a single heat exchange branch. The stable high-temperature combustion air can promote the complete combustion of fuel, reduce the emission of incomplete combustion products, improve the combustion efficiency of the melting furnace by 15%-20%, and achieve higher quality aluminum alloy melting.

[0032] 3. The smoke collection hood adopts a double-layer structure consisting of an inner sealed shell and an outer insulated shell. Combined with the insulation material filled between the wall panels, it not only reduces the smoke leakage rate and avoids environmental pollution, but also reduces the heat loss of the hood, so that the smoke flow is concentrated in the heat exchange pipe and the heat loss rate is reduced. Attached Figure Description

[0033] Figure 1 This is a side view cross-sectional structural diagram of an embodiment of this application.

[0034] Figure 2 This is a front view structural diagram of an embodiment of this application.

[0035] Figure 3 yes Figure 1 A magnified schematic diagram of the structure at point A in the middle.

[0036] Figure 4 This is a front structural diagram of an embodiment of this application.

[0037] Reference numerals: 1. Smoke hood; 101. Smoke inlet; 102. Smoke outlet; 103. Smoke flow channel; 11. Inner smoke flow shell; 12. Outer insulation and protection shell; 2. Water-cooled heat exchange assembly; 21. U-shaped heat exchange tube; 22. Water-cooled manifold inlet pipe; 23. Water-cooled manifold outlet pipe; 3. Fixed hot air heat exchange assembly; 4. Mobile hot air heat exchange assembly; 5. Lifting and traction mechanism; 51. Drive motor; 52. Transmission screw; 53. Screw nut; 54. Guide and limit assembly; 541. Guide rail; 542. Guide slider; 6. Dual-path combustion air mixing system; 61. Combustion air main pipe; 62. First heat exchange branch; 63. Second heat exchange branch; 7. Smoke exhaust pipe; 8. Smoke exhaust control valve; 9. Coil body; 10. Metal bellows expansion joint. Detailed Implementation

[0038] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0039] This application discloses a double-layer fully sealed flue gas collection and heat exchange device for a centralized aluminum alloy melting furnace, suitable for flue gas sealing and collection, waste heat recovery, and constant-temperature combustion air supply under various working conditions such as melting and heat preservation in a centralized aluminum alloy melting furnace. (Refer to...) Figure 1The core of this double-layer fully sealed flue gas collection and heat exchange device includes a flue gas hood 1, which serves as the main support for flue gas collection, heat exchange, and insulation of the entire system. A flue gas inlet 101 is located at the lower end of the flue gas hood 1, and it is tightly fitted to the furnace exhaust port via a flange connection to prevent leakage from assembly gaps. A flue gas outlet 102 is located on the upper side of the flue gas hood 1, and its internal cavity forms a flue gas flow channel 103, allowing for stable upward flow of high-temperature flue gas from the furnace. After heat exchange, the high-temperature flue gas enters the flue gas flow channel 103 through the flue gas inlet 101 and is finally discharged orderly from the flue gas outlet 102.

[0040] Reference Figure 1 and Figure 3 Specifically, to balance sealing and smoke collection with heat insulation performance, the smoke collection hood 1 adopts a double-layer, split-welded, fully sealed box structure, consisting of an inner smoke flow shell 11 and an outer heat insulation and protection shell 12. The inner smoke flow shell 11 is entirely constructed from stainless steel plates, fully welded together with tight, gapless welds to ensure no leakage of high-temperature smoke. A uniform interlayer space is reserved between the inner smoke flow shell 11 and the outer heat insulation and protection shell 12, filled with high-density insulation cotton. This prevents heat loss from the internal smoke from radiating outwards, reducing heat loss and avoiding safety hazards caused by excessively high external temperatures, thus adapting to continuous production environments in workshops.

[0041] Furthermore, the side wall of the fume hood 1 corresponding to the flue gas inlet 101 is provided with an inclined guide surface. The guide surface is inclined from the side away from the flue gas outlet 102 towards the flue gas inlet 101, which can disperse the turbulent flow of flue gas entering the hood, regulate the flow direction of flue gas, and prevent aluminum ash and dust from accumulating in the dead corners at the bottom of the hood, thereby reducing the problem of dust accumulation and blockage of heat exchange components from the source and reducing the frequency of equipment maintenance. The outside of the flue gas outlet 102 is sealed and welded with a flue gas exhaust pipe 7. The middle section of the flue gas exhaust pipe 7 is equipped with a flue gas exhaust control valve 8. The operator can flexibly adjust the valve opening according to the real-time smelting capacity and flue gas flow rate of the furnace, and accurately control the flue gas velocity and heat exchange residence time inside the flue gas flow channel 103 to ensure heat exchange stability under different operating conditions.

[0042] To achieve preliminary recovery and utilization of waste heat from flue gas, a water-cooled heat exchange component 2 is installed in the flue gas flow channel 103 area within the flue gas hood 1, where the main flue gas flow path is inevitably traversed. In this embodiment, industrial circulating soft water is preferably used as the heat exchange medium to achieve initial recovery of basic waste heat from high-temperature flue gas through water-cooled heat exchange. Specifically, the water-cooled heat exchange component 2 consists of 30-50 U-shaped heat exchange tubes 21 arranged in a regular rectangular array. Reasonable flue gas flow gaps are reserved between adjacent U-shaped heat exchange tubes 21 in both the horizontal and vertical directions, ensuring that high-temperature flue gas can smoothly pass through the gaps and fully flush the tube walls, maximizing the gas-liquid heat exchange contact area and ensuring waste heat recovery efficiency.

[0043] All U-shaped heat exchange tubes 21 have their medium inlet ends uniformly connected to the water-cooled manifold inlet pipe 22, and their medium outlet ends uniformly connected to the water-cooled manifold outlet pipe 23. The water-cooled manifold inlet pipe 22 and the water-cooled manifold outlet pipe 23 extend through the double-layer cover wall to the outside of the equipment, achieving stable medium circulation. The gaps between the pipes and the wall penetration holes of the cover are filled with flexible fire-resistant sealing material, which not only fixes the position of the pipes but also seals the gaps to prevent heat loss and flue gas leakage.

[0044] Reference Figure 1 The single U-shaped heat exchange tube 21 is arranged with a height difference, with the vertical height of the medium inlet end being higher than that of the outlet end. The flue gas outlet 102 is located above the outlet end of the U-shaped heat exchange tube 21. The flue gas after water cooling can be discharged quickly and smoothly, avoiding the backflow and stagnation of low-temperature flue gas, stabilizing the heat exchange temperature difference, and ensuring the continuous and efficient operation of the water-cooled heat exchange component 2 system.

[0045] This application adds a dual-path air heat exchange structure to the water-cooled heat exchange system, forming a water-air dual-medium synergistic heat exchange system to improve the waste heat recovery and utilization rate of flue gas. The flue gas flow channel 103 is perpendicular to the flue gas flow direction, with fixed hot air heat exchange components 3 and mobile hot air heat exchange components 4 arranged in parallel. Both sets of components are coil structures, and the coils are interspersed in the gaps of the U-shaped heat exchange tube array 21, allowing high-temperature flue gas to simultaneously scour the water-cooled tube bundle and the hot air coils, synchronously completing heat exchange between flue gas and circulating water, and between flue gas and combustion fresh air, achieving multi-stage waste heat recovery.

[0046] The fixed hot air heat exchanger 3 is fixedly installed in the side area near the flue gas outlet 102. Its position remains constant during operation, and it undertakes the basic fresh air preheating function. The mobile hot air heat exchanger 4 is arranged on the side of the fixed hot air heat exchanger 3 near the flue gas inlet 101. It can move vertically up and down along the flue gas flow channel 103. By changing its distance from the flue gas inlet 101, it can flexibly adjust the effective heat exchange area between the flue gas and the coil to adapt to flue gas conditions with different temperatures and flow rates.

[0047] Reference Figure 2 To accommodate the lifting and lowering requirements of the mobile components, both ends of the coil body 9 of the mobile hot air heat exchange component 4 are equipped with high-temperature resistant stainless steel metal bellows expansion joints 10. The metal bellows expansion joints 10 penetrate through the cover wall to form the medium inlet and outlet. They can absorb the vertical displacement generated by the lifting and lowering of the component through their own elastic deformation, solve the problems of rigid pipe pulling and cracking and hot air leakage, and ensure the sealing and stability of the heat exchange air circuit.

[0048] Reference Figure 1 and Figure 3A lifting and traction mechanism 5 is installed on the outer side of the top of the smoke collection hood 1. This mechanism is used to drive the mobile hot air heat exchange component 4 to vertically and steplessly adjust its height. The equipment operates smoothly, with high adjustment accuracy and no jamming. The mechanism mainly includes a variable frequency drive motor 51 with self-locking brake function, a transmission screw 52, ​​a screw nut 53, and a guide limit component 54. Specifically, the drive motor 51 is a variable frequency motor with self-locking brake function. The motor output shaft is coaxially fixed with the transmission screw 52, ​​which can accurately drive the transmission screw 52 to rotate in both directions. The screw nut 53 is threaded onto the transmission screw 52. When the screw rotates, it can drive the screw nut 53 to rise and fall vertically.

[0049] In this embodiment, the guide limiting component 54 includes multiple hollow structure guide rails 541 that are uniformly welded and fixed to the inner side wall of the inner flue gas circulation shell 11. The transmission screw 52 is arranged vertically inside the hollow guide rails 541, realizing the built-in hidden installation of the screw and avoiding the disadvantage of easy dust accumulation in external screws.

[0050] A long guide groove is provided on the side of the guide rail 541 facing the flue gas duct 103. A guide slider 542 is slidably mounted inside the guide groove. The outer side of the guide slider 542 is welded and fixed to the frame of the movable hot air heat exchange component 4. The inner side of the guide slider 542 is rigidly fixed to the screw nut 53 inside the guide rail 541. When the screw nut 53 rotates and rises and falls vertically with the rotation of the transmission screw 52, ​​the guide slider 542 and the movable hot air heat exchange component 4 as a whole perform vertical linear reciprocating motion, realizing stepless fine adjustment of the lifting stroke. It can be precisely self-locked at any height to meet the fine adjustment needs of different heat exchange areas.

[0051] Furthermore, each guide rail 541 is equipped with an accordion-style telescopic protective cover (not shown in the attached diagram). The two ends of the telescopic protective cover are fixed to the outer wall of the guide rail 541 and the end face of the guide slider 542, respectively. It can extend and retract synchronously with the lifting stroke of the component, fully covering the guide groove area. This completely isolates the internal transmission structure of the guide rail from external dusty fumes, preventing dust and aluminum ash from falling into the guide rail and the thread gap of the lead screw. This avoids malfunctions such as dust accumulation and jamming, thread wear, and transmission accuracy reduction, thus improving the service life and long-term adjustment accuracy of the mechanism. In addition, limit blocks are welded and fixed to the upper and lower ends of the guide rail 541. These limit blocks form a physical limit, restricting the maximum upward and downward sliding stroke of the guide slider 542. This prevents the mobile hot air heat exchange component 4 from over-traveling and impacting the fixed hot air heat exchange component 3 at the bottom or top of the cover, avoiding impact deformation of the heat exchange coil and ensuring the stability of equipment operation.

[0052] Reference Figure 2 and Figure 4To achieve precise temperature control of the preheating combustion air, a dual-path combustion air mixing system 6 is independently installed on the outside of the smoke hood 1. The entire system mainly consists of a main combustion air duct 61, a first heat exchange branch 62, and a second heat exchange branch 63. During equipment operation, ambient temperature and pressure outside fresh air is divided into two independent paths, which are respectively introduced into the fixed hot air heat exchange component 3 and the mobile hot air heat exchange component 4 to complete heat absorption and preheating. Among them, the hot air that has been fully preheated by the fixed hot air heat exchange component 3 is merged into the main combustion air duct 61 through the first heat exchange branch 62. The hot air that has been heat-exchanged by the coil body 9 of the mobile hot air heat exchange component 4 and stably transported by the metal corrugated pipe expansion joint 10 is then simultaneously sent into the main combustion air duct 61 through the second heat exchange branch 63.

[0053] After the two preheated hot air streams at different temperatures enter the combustion air main duct 61, they can be fully turbulently mixed inside the cavity to form a uniformly heated combustion air stream. In actual operation, operators can adjust the height of the movable hot air heat exchange component 4 to change the preheating temperature of the hot air corresponding to the second heat exchange branch 63, thereby adjusting the mixing temperature of the two hot air streams and precisely controlling the output temperature of the combustion air main duct 61 to achieve a constant-temperature combustion air supply. Those skilled in the art will understand that flow detection sensors, temperature detection sensors, and flow control valves can be correspondingly configured on the first heat exchange branch 62 and the second heat exchange branch 63 to detect the hot air flow and temperature parameters inside each heat exchange branch in real time. Based on the target combustion air temperature required by the smelting process, the flow control valves can precisely regulate the hot air ratio of the two heat exchange branches entering the combustion air main duct 61, further improving the accuracy and stability of the combustion air temperature control. Finally, the temperature-controlled and mixed constant-temperature combustion air is directly delivered to the combustion lance of the aluminum alloy melting furnace, which can promote the complete combustion of fuel, improve combustion efficiency, reduce the generation of black smoke and fuel consumption during aluminum smelting, and has both energy-saving and environmental protection benefits.

[0054] This device adopts a layered and staged heat exchange and dynamically adjustable structural design, which differs from traditional fixed single-stage heat exchange and flue gas collection equipment. It can adapt to the different heat exchange requirements of aluminum alloy melting furnaces under different operating conditions, and has extremely strong operational adaptability. Under the high-load continuous melting conditions of the furnace, the flue gas temperature is high and the flow rate is large. The moving hot air heat exchange component 4 is driven downward by the lifting and traction mechanism 5, so that it is close to the flue gas inlet 101, fully contacting the high-temperature mainstream flue gas, maximizing the hot air heat exchange area, increasing the preheating temperature of the combustion air, and matching the combustion heating requirements of high-capacity melting. At the same time, a large flow of circulating soft water continuously removes the waste heat of the flue gas, realizing the efficient recovery and utilization of waste heat.

[0055] Under low-load heat preservation conditions in the furnace, the flue gas temperature and flow rate are significantly reduced, eliminating the need for ultra-high-temperature combustion air. The drive motor 51 moves the mobile hot air heat exchange component 4 upwards, away from the flue gas inlet 101, reducing the contact area between the low-temperature flue gas and the coil body 9. This lowers the preheating temperature of the fresh air in the second heat exchange branch 63. By mixing with the medium-temperature hot air from the first heat exchange branch 62, the combustion air temperature is stably controlled within the process-suitable range, avoiding problems such as chaotic combustion within the furnace and overheating oxidation of the molten aluminum caused by excessively high combustion air temperatures. Combined with the opening adjustment of the exhaust control valve 8, the flue gas flow rate can be precisely controlled, extending the heat exchange residence time of low-flow flue gas and ensuring that the waste heat recovery efficiency does not decrease under low operating conditions.

[0056] This device relies on a double-layer fully sealed hood structure, which fundamentally solves the defects of traditional single-layer fume hoods such as gas leakage and severe heat dissipation. Combined with the anti-ash accumulation design of the inclined guide surface, the self-adjustable heat exchange structure, and the bellows displacement compensation structure, it can achieve stable operation without leakage, pulling, or ash accumulation, reduce the frequency of downtime maintenance, increase the continuous operation time of the equipment, and is suitable for long-term continuous production operations in aluminum alloy centralized melting furnaces. It has good practicality and promotion value.

[0057] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A double-layer fully sealed flue gas collection and heat exchange device for a centralized aluminum alloy melting furnace, characterized in that, include: The fume hood is installed at the flue gas emission position of the aluminum alloy centralized melting furnace. It has a double-layer sealed box structure. The fume hood has a flue gas inlet at the lower end and a flue gas outlet on the upper side. The interior forms a flue gas flow channel for the flue gas to flow from bottom to top. The water-cooled heat exchange component is integrally arranged inside the flue gas flow channel of the smoke collection hood, and the liquid inlet of the water-cooled heat exchange component is located on the side close to the flue gas outlet. The fixed hot air heat exchanger is arranged in a plane perpendicular to the flue gas flow direction and is located in the area of ​​the water-cooled heat exchanger near the flue gas outlet. A mobile hot air heat exchange component is located on the side of the fixed hot air heat exchange component near the flue gas inlet and is parallel to the plane of the fixed hot air heat exchange component. The mobile hot air heat exchange component can move up and down along the vertical flue gas flow direction to get closer to or away from the flue gas inlet. A lifting and traction mechanism is installed on the smoke collection hood and is used to drive the mobile hot air heat exchange component to lift and lower. A dual-path combustion air mixing system is installed on the outside of the smoke hood. Both the fixed hot air heat exchange component and the mobile hot air heat exchange component are connected to the dual-path combustion air mixing system. The air after heat exchange is mixed in the dual-path combustion air mixing system to form combustion air at the target temperature.

2. The double-layer fully sealed flue gas collection and heat exchange device for the centralized aluminum alloy melting furnace according to claim 1, characterized in that: The water-cooled heat exchange assembly includes multiple U-shaped heat exchange tubes arranged in a rectangular array, which are arranged in a rectangular array along the transverse and longitudinal directions of the smoke collection hood. Both the fixed hot air heat exchanger and the mobile hot air heat exchanger are coil structures, with the coils and U-shaped heat exchange tubes interlaced and arranged.

3. The double-layer fully sealed flue gas collection and heat exchange device for the centralized aluminum alloy melting furnace according to claim 2, characterized in that: The inlet ends of all the U-shaped tubes are interconnected and connected to a water-cooled manifold inlet pipe, and the outlet ends of all the U-shaped tubes are interconnected and connected to a water-cooled manifold outlet pipe. The water-cooled manifold inlet pipe and the water-cooled manifold outlet pipe extend to the outside through the wall panel of the smoke collection hood. The vertical height of the inlet end of each U-shaped tube is higher than that of the outlet end, and the flue gas outlet of the smoke collection hood is located above the outlet end of the U-shaped tube and corresponds to the flue gas outlet in the horizontal direction; The fixed hot air heat exchanger is located in the space between the inlet and outlet ends of the U-shaped tube, close to the flue gas outlet.

4. The double-layer fully sealed flue gas heat exchange device for the centralized aluminum alloy melting furnace according to claim 1, characterized in that: The lifting and traction mechanism includes a drive motor, a transmission screw, and a screw nut. The drive motor is installed on the top of the outer side of the smoke collection hood. The output shaft of the drive motor is coaxially fixed with the transmission screw. The screw nut is threaded onto the transmission screw. The movable hot air heat exchange component is connected to the screw nut so that it can be lifted and lowered in the vertical direction.

5. The double-layer fully sealed flue gas collection and heat exchange device for the centralized aluminum alloy melting furnace according to claim 4, characterized in that: The lifting and traction mechanism also includes a guide and limiting component, which includes multiple hollow guide rails evenly distributed on the inner side wall of the smoke collection hood, and the transmission screw and screw nut are both located inside the guide rails. Each of the guide rails has a guide groove on the side facing the flue gas passage, and a guide slider is slidably installed in the guide groove. The guide slider is fixedly connected to the movable hot air heat exchange component, and the nut seat is fixedly connected to the guide slider.

6. The double-layer fully sealed flue gas collection and heat exchange device for the centralized aluminum alloy melting furnace according to claim 1, characterized in that: The dual-path combustion air mixing system includes a combustion air main pipe, a first heat exchange branch, and a second heat exchange branch. The outlet end of the fixed hot air heat exchange component is connected to the first heat exchange branch, and the outlet end of the mobile hot air heat exchange component is connected to the second heat exchange branch. Both the first and second heat exchange branches are connected to the combustion air main pipe.

7. The double-layer fully sealed flue gas heat exchange device for the centralized aluminum alloy melting furnace according to claim 1, characterized in that: The double-layer sealed box structure of the smoke collection hood includes an inner smoke flow shell and an outer heat insulation and protection shell, and the wall panels of the inner smoke flow shell are sealed together to form a sealed cavity; The space between the inner flue gas circulation shell and the outer thermal insulation protective shell is filled with thermal insulation material.

8. The double-layer fully sealed flue gas heat exchange device for the centralized aluminum alloy melting furnace according to claim 1, characterized in that: A smoke exhaust pipe is sealed and installed on the outside of the smoke collection hood at the position corresponding to the smoke outlet, and a smoke exhaust control valve is installed in the middle section of the smoke exhaust pipe; The side of the smoke collection hood opposite the smoke inlet is an inclined guide surface, and the side of the inclined guide surface away from the exhaust pipe is inclined towards the smoke inlet.

9. The double-layer fully sealed flue gas heat exchange device for the centralized aluminum alloy melting furnace according to claim 1, characterized in that: The mobile hot air heat exchanger includes a coil body, with metal bellows expansion joints connected to both ends of the coil body. The metal bellows expansion joints pass through the wall panel of the smoke hood to form a medium inlet and a medium outlet. The medium outlet is connected to a dual-path combustion air mixing system.

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