A method and system for improving the quality of low-quality sintering flue gas waste heat

Abstract

This invention relates to the field of waste heat recovery technology, and discloses a method and system for recovering waste heat from low-quality sintering flue gas, including a heat exchanger shell. The invention uses a diversion assembly composed of a diversion tube and a temporary storage tube to precisely separate the near-wall low-temperature flue gas from the central high-temperature flue gas within the heat exchange tubes, preventing the low-temperature flue gas from lowering the overall heat exchange temperature. Simultaneously, a sealing plug is used to block and retain the high-temperature flue gas within the temporary storage tube, extending the heat exchange time and achieving deep heat exchange of the central high-temperature flue gas. This overcomes the adverse effects of the near-wall low-temperature boundary layer, fully extracting and utilizing the waste heat from the low-quality sintering flue gas, significantly improving the waste heat quality and recovery rate, and reducing energy waste. Furthermore, a drive assembly drives the sealing plate and sealing plug in a linked action. The fan-shaped sealing plate provides intermittent sealing and conduction to three sets of annularly distributed heat exchange tubes, and the reciprocating motion of the sealing plug within the barrier chamber ensures stable waste heat recovery performance.

Description

Technical Field

[0001] This invention belongs to the field of waste heat upgrading technology, specifically, it relates to a method and system for upgrading the waste heat of low-quality sintering flue gas. Background Technology

[0002] During the steel sintering process, a large amount of low-quality sintering flue gas is generated. This flue gas has a low temperature, large temperature fluctuations, and high dust content. It is a low-grade waste heat resource that is difficult to recover and utilize directly. Currently, most of it is directly emitted, which not only causes serious energy waste but also brings certain environmental thermal pollution, which does not meet the needs of green and low-carbon industrial development.

[0003] In existing low-quality sintering flue gas waste heat upgrading systems, radial temperature stratification is common when flue gas flows in heat exchange pipes. Flue gas near the pipe wall cools down faster and forms a low-temperature boundary layer, while flue gas in the central area of ​​the pipe flows faster and cools down slower, so the heat cannot be fully absorbed. This results in low-temperature flue gas being mixed with high-temperature flue gas and discharged, which significantly reduces the overall heat exchange efficiency and causes waste heat.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows: A waste heat upgrading system for low-quality sintering flue gas includes a heat exchanger shell.

[0006] The heat exchanger shell is equipped with three sets of heat exchange tubes for introducing flue gas, and the three sets of heat exchange tubes are arranged in a ring. The heat exchange tube is also equipped with a flow distribution assembly, which includes a flow distribution tube and a temporary storage tube. The flow distribution tube and the temporary storage tube are respectively installed at the end of the heat exchange tube, and the inner cavities of the flow distribution tube and the temporary storage tube are connected to the inner cavity of the heat exchange tube. The inlet of the flow distribution tube corresponds to the side wall of the inner cavity of the heat exchange tube, which is used to guide the gas that has completed heat exchange to be discharged. The temporary storage tube corresponds to the center of the heat exchange tube, which is used to guide the gas that has not completed heat exchange in the center to flow to the temporary storage tube for heat exchange. The inlet of the temporary storage tube has a barrier chamber, which is conical in shape, and a sealing plug is inserted into the barrier chamber. The sealing plug is used to block the flow of gas and to increase the heat exchange time of the gas inside the temporary storage tube. A sealing plate is rotatably installed at the inlet of each of the three heat exchange tubes. The sealing plate is fan-shaped and has a central angle of 150°. The sealing plate is used to seal the gaps between the corresponding heat exchange tubes. A drive assembly for driving the movement of the sealing plate and the sealing plug is also installed between them.

[0007] In a preferred embodiment of the present invention, a fixing block is installed on the back of the heat exchanger shell, a fixing plate is installed at the end of the fixing block, the fixing block and the fixing plate are T-shaped, four fixing holes are installed at the corner of the fixing plate, and several pairs of reinforcing members are installed at the connection between the fixing plate and the fixing block, and the reinforcing members are triangular.

[0008] In a preferred embodiment of the present invention, end covers are installed at both ends of the heat exchanger shell. One end cover has three through holes, and the corresponding through holes are connected to the side wall of the heat exchange tube. The other end cover is also provided with a drive assembly, and the end cover is also connected to the diversion tube and the temporary storage tube.

[0009] In a preferred embodiment of the present invention, a water inlet pipe is installed at one end of the heat exchanger shell and a water outlet pipe is installed at the other end of the heat exchanger shell. Both the water inlet pipe and the water outlet pipe are bent. The water inlet pipe and the water outlet pipe are integrally cast with the heat exchanger shell. The height of the water inlet pipe is lower than the height of the water outlet pipe. The water inlet pipe is located on the side where the heat exchange tube is installed, and the water outlet pipe is installed on the other side.

[0010] In a preferred embodiment of the present invention, an air inlet pipe is installed on the end cover connected to one end of the heat exchange tube, and an air outlet pipe is installed on the end cover connected to one end of the split pipe. The air inlet pipe, air outlet pipe, water inlet pipe and water outlet pipe are all integrally cast with connecting flanges, and the connecting flanges are provided with connecting holes for easy connection.

[0011] In a preferred embodiment of the present invention, the diversion tube is located outside the temporary storage tube, the diversion tube has a diversion cavity, and the diversion tube has a notch, the notch being used to allow the inner cavity of the heat exchanger shell to contact the outer wall of the temporary storage tube.

[0012] In a preferred embodiment of the present invention, the driving assembly includes a turntable, a driving motor is mounted on the outer wall of the end cover, the output end of the driving motor is connected to the end cover and the output end of the driving motor is connected to the turntable, and the turntable is placed on a communicating cavity opened inside the end cover.

[0013] In a preferred embodiment of the present invention, a synchronous shaft is installed at the rotation center of the turntable. The synchronous shaft is movably connected to the side walls of the two end covers, and the end of the synchronous shaft is connected to the rotation center of the sealing plate. The sealing plate is made of rubber.

[0014] In a preferred embodiment of the present invention, a protrusion is installed on the turntable, and both ends of the protrusion are chamfered. The central angle of the protrusion corresponds to the central angle of the sealing plate. A synchronizing rod is slidably installed on the protrusion, and the end of the synchronizing rod is connected to the end of the sealing plug. The synchronizing rod moves through the temporary storage tube. A reset seat is slidably installed on the synchronizing rod and is installed on the side wall of the end cover. A baffle is installed on the synchronizing rod. A reset spring is sleeved on the synchronizing rod. One end of the reset spring is engaged with the baffle, and the other end of the reset spring is engaged with the side wall of the reset seat. A ball is installed at the end of the synchronizing rod. The reset spring is used to drive the ball to fit against the side wall of the protrusion. A rib is installed on the reset seat and is installed in the inner cavity of the end cover.

[0015] A method for improving the quality of low-quality sintering flue gas using waste heat includes the following steps: Step 1: Dust-laden, low-quality sintering flue gas enters the end cover through the inlet pipe. Under the guidance of the sealing plate and the flow control of the gap, it enters the heat exchange tubes distributed in a ring inside the heat exchanger shell. The external heat exchange medium, water, enters the heat exchanger shell through the lower water inlet pipe, forming a counter-current flow heat exchange with the flue gas in the heat exchange tube. The heated medium is discharged through the higher water outlet pipe, realizing the initial recovery of low-quality waste heat. Step 2: During the flow of flue gas in the heat exchange tube, the low-temperature flue gas near the tube wall and the high-temperature flue gas in the central area form radial temperature stratification. The low-temperature flue gas near the tube wall that has completed heat exchange enters the diversion tube along the side wall of the heat exchange tube, while the high-temperature flue gas in the central area that has not completed heat exchange enters the temporary storage tube, thus realizing the diversion and guidance of high and low temperature flue gas. Step 3: The drive motor drives the turntable to rotate. The protrusions on the turntable cooperate with the ball drive to move the synchronous rod axially, causing the sealing plug to reciprocate in the conical barrier chamber. When the sealing plug is inserted into the barrier chamber, the high-temperature flue gas in the temporary storage tube is blocked and retained, extending the heat exchange time to achieve deep heat exchange and quality improvement. Step 4: The turntable drives the sealing plate to rotate synchronously through the synchronous shaft. The fan-shaped sealing plate performs intermittent sealing and conduction on the inlet of the three sets of heat exchange tubes. In conjunction with the blocking action of the sealing plug, the flue gas flow rate, velocity and residence time are dynamically adjusted to avoid incomplete heat exchange. Step 5: When the sealing plug exits the barrier chamber, the flue gas that has completed sufficient heat exchange and upgrading in the temporary storage tube flows into the diversion tube. After merging with the low-temperature flue gas in the diversion tube, it is discharged through the outlet pipe, completing the entire process of waste heat upgrading and heat exchange of low-quality sintering flue gas.

[0016] Compared with the prior art, the present invention has the following advantages: This invention uses a diversion assembly consisting of a diversion tube and a temporary storage tube to precisely separate the near-wall low-temperature flue gas from the central high-temperature flue gas within the heat exchange tube. This prevents the low-temperature flue gas from lowering the overall heat exchange temperature. Simultaneously, a sealing plug is used to block and retain the high-temperature flue gas within the temporary storage tube, extending the heat exchange time and achieving deep heat exchange for the central high-temperature flue gas. This overcomes the adverse effects of the near-wall low-temperature boundary layer, fully extracting and utilizing the waste heat from the low-quality sintering flue gas, significantly improving the waste heat quality and recovery rate, and reducing energy waste. Furthermore, a drive assembly drives the sealing plate and sealing plug to move in tandem. The fan-shaped sealing plate provides intermittent sealing and conduction for the three sets of annularly distributed heat exchange tubes. Combined with the reciprocating motion of the sealing plug within the barrier chamber, this ensures a stable waste heat quality improvement effect.

[0017] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0018] In the attached diagram: Figure 1 A three-dimensional diagram of a low-quality sintering flue gas waste heat upgrading system; Figure 2 A bottom view of a low-quality sintering flue gas waste heat upgrading system. Figure 3 A cross-sectional view of the heat exchanger shell of a low-quality sintering flue gas waste heat upgrading system. Figure 4 A schematic diagram of a partial structure of a low-quality sintering flue gas waste heat upgrading system. Figure 1 ; Figure 5 A waste heat upgrading system for low-quality sintering flue gas Figure 4 Enlarged view of point A in the middle; Figure 6 A schematic diagram of a partial structure of a low-quality sintering flue gas waste heat upgrading system. Figure 2 ; Figure 7 A cross-sectional view of the diversion pipe and temporary storage pipe of a low-quality sintering flue gas waste heat upgrading system. Figure 8 A waste heat upgrading system for low-quality sintering flue gas Figure 7 Enlarged view at point B in the middle; Figure 9 This is a structural diagram of the sealing plate of a low-quality sintering flue gas waste heat upgrading system.

[0019] In the diagram: 1. Heat exchanger shell; 2. Fixing block; 3. Fixing plate; 4. Reinforcing member; 5. Fixing hole; 6. Water inlet pipe; 7. Water outlet pipe; 8. Connecting flange; 9. End cover; 10. Air inlet pipe; 11. Air outlet pipe; 12. Heat exchange tube; 13. Diverter pipe; 14. Notch; 15. Diverter chamber; 16. Temporary storage pipe; 17. Barrier chamber; 18. Sealing plug; 19. Synchronizing rod; 20. Turntable; 21. Drive motor; 22. Protrusion; 23. Ball bearing; 24. Baffle; 25. Return spring; 26. Return seat; 27. Rib plate; 28. Connecting cavity; 29. ​​Synchronizing shaft; 30. Sealing plate; 31. Through hole. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention.

[0021] Example 1:

[0022] like Figures 1 to 9 As shown, a low-quality sintering flue gas waste heat upgrading system includes a heat exchanger shell 1. Three sets of heat exchange tubes 12 for introducing flue gas are installed inside the heat exchanger shell 1, and the three sets of heat exchange tubes 12 are arranged in a ring. A flow-dividing assembly is also installed on the heat exchange tube 12. The flow-dividing assembly includes a flow-dividing tube 13 and a temporary storage tube 16. The flow-dividing tube 13 and the temporary storage tube 16 are respectively installed at the ends of the heat exchange tube 12, and the inner cavities of the flow-dividing tube 13 and the temporary storage tube 16 are connected to the inner cavity of the heat exchange tube 12. The inlet of the flow-dividing tube 13 corresponds to the side wall of the inner cavity of the heat exchange tube 12, which is used to guide the gas that has completed heat exchange to be discharged. The temporary storage tube 16 corresponds to the center of the heat exchange tube 12, which is used to guide the gas that has not completed heat exchange in the center to flow to the temporary storage tube 16 for heat exchange. The inlet of the temporary storage tube 16 is provided with a barrier chamber 17, which is conical in shape, and a sealing plug 18 is inserted inside the barrier chamber 17. The sealing plug 18 is used to block the gas flow and to increase the gas heat exchange time inside the temporary storage tube 16. A sealing plate 30 is rotatably installed at the inlet of the three sets of heat exchange tubes 12. The sealing plate 30 is fan-shaped and the central angle of the sealing plate 30 is 150°. The sealing plate 30 is used to gap seal the corresponding heat exchange tube 12. A drive assembly for driving the movement of the sealing plate 30 and the sealing plug 18 is also installed between them.

[0023] like Figures 1 to 9As shown in the specific embodiment, a fixing block 2 is installed on the back of the heat exchanger shell 1, and a fixing plate 3 is installed at the end of the fixing block 2. The fixing block 2 and the fixing plate 3 are T-shaped. Four fixing holes 5 are installed at the corners of the fixing plate 3. Several pairs of reinforcing members 4 are installed at the connection between the fixing plate 3 and the fixing block 2, and the reinforcing members 4 are triangular. The T-shaped fixing block 2 and the fixing plate 3, together with the triangular reinforcing members 4, can enhance the stability of the equipment installation. The four fixing holes 5 facilitate the quick fixing of the equipment, avoid shaking during equipment operation, and extend the service life of the heat exchanger shell 1 and the entire system.

[0024] like Figures 1 to 9 As shown, furthermore, end covers 9 are installed at both ends of the heat exchanger shell 1. One end cover 9 has three through holes 31, and the corresponding through holes 31 are connected to the side wall of the heat exchange tube 12. The other end cover 9 is also equipped with a drive assembly, and the interior of the end cover 9 is also connected to the diversion pipe 13 and the temporary storage pipe 16. The end cover 9 can provide sealing protection for the heat exchange tube 12, the drive assembly, the diversion pipe 13 and the temporary storage pipe 16. The through holes 31 can achieve a stable connection between the heat exchange tube 12 and the end cover 9, and at the same time provide guidance for the flow of flue gas, ensuring that the flue gas smoothly enters the interior of the heat exchange tube 12.

[0025] like Figures 1 to 9 As shown, furthermore, a water inlet pipe 6 is installed at one end of the heat exchanger shell 1, and a water outlet pipe 7 is installed at the other end of the heat exchanger shell 1. Both the water inlet pipe 6 and the water outlet pipe 7 are bent. The water inlet pipe 6 and the water outlet pipe 7 are integrally cast with the heat exchanger shell 1. The height of the water inlet pipe 6 is lower than the height of the water outlet pipe 7. The water inlet pipe 6 is located on the side where the heat exchange tube 12 is installed, and the water outlet pipe 7 is installed on the other side. The integrally cast water inlet pipe 6 and water outlet pipe 7 with the heat exchanger shell 1 can improve the sealing of the pipeline and avoid water and heat leakage. The height difference and position distribution of the water inlet pipe 6 and water outlet pipe 7 can realize the reverse flow of the heat exchange medium, improve the heat exchange efficiency, and the bent structure can adapt to the equipment installation space, enhancing practicality.

[0026] like Figures 1 to 9 As shown, furthermore, an air inlet pipe 10 is installed on the end cover 9 connected to one end of the heat exchange tube 12, and an air outlet pipe 11 is installed on the end cover 9 connected to one end of the branch pipe 13. Connecting flanges 8 are integrally cast at the joints of the air inlet pipe 10, air outlet pipe 11, water inlet pipe 6, and water outlet pipe 7, and the connecting flanges 8 have connection holes for easy connection. The air inlet pipe 10 and air outlet pipe 11 allow for smooth entry and exit of flue gas. The connecting flanges 8 enable quick docking of this system with existing sintering flue gas treatment pipelines and heat exchange pipelines. The connection holes improve the convenience and stability of the connection, ensure the sealing of the pipeline connection, and reduce leakage of flue gas and heat exchange medium.

[0027] Example 2:

[0028] The difference between the above embodiments and this embodiment is that: Figures 1 to 9 As shown, the diversion pipe 13 is located outside the temporary storage pipe 16. A diversion cavity 15 and a notch 14 are provided on the diversion pipe 13, allowing the inner cavity of the heat exchanger shell 1 to contact the outer wall of the temporary storage pipe 16. The diversion pipe 13's location outside the temporary storage pipe 16 enables the orderly diversion of high and low temperature flue gas. The diversion cavity 15 facilitates the rapid collection and discharge of low-temperature flue gas. The notch 14 allows for full contact between the outer wall of the temporary storage pipe 16 and the heat exchange medium within the heat exchanger shell 1, further improving the heat exchange efficiency of the high-temperature flue gas within the temporary storage pipe 16 and enhancing the waste heat treatment effect.

[0029] like Figures 1 to 9 As shown, in a specific embodiment, the drive assembly includes a turntable 20. A drive motor 21 is mounted on the outer wall of the end cover 9. The output end of the drive motor 21 is connected to the end cover 9 and the turntable 20. The turntable 20 is placed on a communicating cavity 28 opened inside the end cover 9. The drive motor 21 provides stable power to the entire drive assembly. The turntable 20 can transmit the rotational power of the drive motor 21 to subsequent components. The communicating cavity 28 provides a stable rotational space for the turntable 20, avoiding interference between the turntable 20 and the end cover 9 during rotation, and ensuring the stability of the drive assembly operation.

[0030] like Figures 1 to 9 As shown, a synchronous shaft 29 is further installed at the rotation center of the turntable 20. The synchronous shaft 29 is movably connected to the side walls of the two end covers 9, and the end of the synchronous shaft 29 is connected to the rotation center of the sealing plate 30. The sealing plate 30 is made of rubber. The synchronous shaft 29 enables the synchronous movement of the turntable 20 and the sealing plate 30, ensuring the coordination of the drive components. The rubber sealing plate 30 improves the sealing effect, reduces wear between the sealing plate 30 and the inlet of the heat exchange tube 12, extends the service life of the sealing plate 30, and provides a better gap sealing effect.

[0031] like Figures 1 to 9As shown, further, a protrusion 22 is installed on the turntable 20, and both ends of the protrusion 22 are chamfered. The central angle of the protrusion 22 corresponds to the central angle of the sealing plate 30. A synchronizing rod 19 is slidably installed on the protrusion 22, and the end of the synchronizing rod 19 is connected to the end of the sealing plug 18. The synchronizing rod 19 moves through the temporary storage tube 16. A reset seat 26 is slidably installed on the synchronizing rod 19, and the reset seat 26 is installed on the side wall of the end cover 9. A baffle 24 is installed on the synchronizing rod 19. A reset spring 25 is sleeved on the synchronizing rod 19. One end of the reset spring 25 is engaged with the baffle 24, and the other end of the reset spring 25 is engaged with the side wall of the reset seat 26. A ball bearing 23 is installed at the end of the synchronizing rod 19. The reset spring 25 is used to drive the ball bearing 23 to fit against the side wall of the protrusion 22. A rib 27 is installed on the reset seat 26, and the rib 27 is installed in the inner cavity of the end cover 9. The cooperation between the protrusion 22 and the ball 23 enables the smooth axial movement of the synchronizing rod 19. The chamfering reduces wear. The return spring 25 enables the synchronizing rod 19 and the sealing plug 18 to automatically reset. The reset seat 26 provides a guide for the synchronizing rod 19. The baffle 24 ensures the installation stability of the return spring 25. The rib 27 enhances the structural strength of the reset seat 26, ensuring that the drive assembly operates accurately, stably and reliably.

[0032] This invention also discloses a method for improving the quality of low-quality sintering flue gas using waste heat, the steps of which are as follows: Step 1: Dust-laden, low-quality sintering flue gas enters the end cover 9 through the inlet pipe 10. Under the guidance and gap control of the sealing plate 30, it enters the heat exchange tubes 12 arranged in a ring inside the heat exchanger shell 1. The external heat exchange medium, water, enters the heat exchanger shell 1 through the lower water inlet pipe 6, forming a counter-current flow heat exchange with the flue gas in the heat exchange tubes 12. The heated medium is discharged through the higher water outlet pipe 7, realizing the initial recovery of low-quality waste heat. Step 2: During the flow of flue gas in the heat exchange tube 12, the low-temperature flue gas near the tube wall and the high-temperature flue gas in the central area form a radial temperature stratification. The low-temperature flue gas near the tube wall that has completed heat exchange enters the diversion tube 13 along the side wall of the heat exchange tube 12, while the high-temperature flue gas in the central area that has not completed heat exchange enters the temporary storage tube 16, thereby achieving the diversion and guidance of high and low temperature flue gas. Step 3: Drive motor 21 drives turntable 20 to rotate. The protrusion 22 on turntable 20 cooperates with ball bearing 23 to drive synchronous rod 19 to move axially, so that sealing plug 18 reciprocates in conical barrier chamber 17. When sealing plug 18 is inserted into barrier chamber 17, high-temperature flue gas in temporary storage tube 16 is blocked and retained, extending heat exchange time to achieve deep heat exchange and quality improvement. Step 4: The turntable 20 drives the sealing plate 30 to rotate synchronously through the synchronous shaft 29. The fan-shaped sealing plate 30 performs intermittent sealing and conduction on the inlet of the three sets of heat exchange tubes 12. In conjunction with the blocking action of the sealing plug 18, the flue gas flow rate, velocity and residence time are dynamically adjusted to avoid incomplete heat exchange. Step 5: When the sealing plug 18 exits the barrier chamber 17, the flue gas that has completed sufficient heat exchange and upgrading in the temporary storage tube 16 flows into the diversion tube 13 and merges with the low-temperature flue gas in the diversion tube 13 before being discharged through the outlet tube 11, thus completing the entire process of waste heat upgrading and heat exchange of the low-quality sintering flue gas.

[0033] The implementation principle of the low-quality sintering flue gas waste heat upgrading system of the present invention is as follows: Dust-laden, low-quality sintering flue gas enters the end cover 9 through the inlet pipe 10. Under the guidance and flow control of the sealing plate 30, it enters the three sets of heat exchange tubes 12 arranged in a ring inside the heat exchanger shell 1. The external heat exchange medium, water, enters the heat exchanger shell 1 through the lower inlet pipe 6, forming a counter-current flow heat exchange with the flue gas in the heat exchange tubes 12. The heated heat exchange medium is discharged through the higher outlet pipe 7, thus initially recovering and utilizing the low-quality waste heat in the flue gas.

[0034] Because the flue gas exhibits uneven radial temperature distribution during its axial flow within the heat exchange tube 12, the flue gas near the tube wall cools down rapidly and experiences a significant temperature drop, resulting in a more thorough heat exchange. However, the flue gas in the central region of the heat exchange tube 12 flows faster and cools down more slowly, failing to absorb sufficient heat. Direct discharge of this flue gas would lead to a significant waste of heat. Therefore, a diversion assembly consisting of a diversion pipe 13 and a temporary storage pipe 16 is installed at the end of the heat exchange tube 12. The diversion pipe 13 corresponds to the side wall region of the heat exchange tube 12, while the temporary storage pipe 16 corresponds to the central region of the heat exchange tube 12. When the flue gas flows to the end of the heat exchange tube 12, the low-temperature flue gas that is close to the tube wall and has completed sufficient heat exchange enters the diversion tube 13 and flows directly into the outlet tube 11 through the diversion cavity 15 and the notch 14 for discharge. Meanwhile, the flue gas with a higher temperature in the central area and incomplete heat exchange enters the temporary storage tube 16. This achieves the diversion of low-temperature flue gas and high-temperature flue gas, avoids the low-temperature flue gas from lowering the overall heat exchange temperature, and improves the effective grade of waste heat recovery.

[0035] During system operation, the drive motor 21 provides power, causing the turntable 20 to rotate within the communicating cavity 28 inside the end cover 9. The protrusion 22 on the turntable 20 rotates accordingly. The protrusion 22, through its cooperation with the ball bearing 23, drives the synchronizing rod 19 to move axially. Guided by the reset seat 26, the synchronizing rod 19 drives the sealing plug 18 to reciprocate within the conical barrier chamber 17. When the sealing plug 18 is inserted into the end of the barrier chamber 17, the airflow channel inside the temporary storage tube 16 is blocked. The central high-temperature flue gas entering the temporary storage tube 16 cannot flow out quickly, forming a temporary stagnation inside the temporary storage tube 16. This prolongs the contact heat exchange time between the high-temperature flue gas and the heat exchange medium inside the heat exchanger shell 1, allowing the waste heat carried by the central flue gas to be further fully absorbed, achieving deep quality improvement of waste heat. When the sealing plug 18 exits the barrier chamber 17 under the action of the return spring 25, the flue gas that has completed sufficient heat exchange is released from the barrier, flows into the diversion pipe 13 and merges with the low-temperature flue gas near the wall, and is finally discharged through the outlet pipe 11.

[0036] Meanwhile, the turntable 20 transmits power to the sealing plate 30 at the other end via the synchronous shaft 29, causing the fan-shaped sealing plate 30 to rotate synchronously. The sealing plate 30 provides intermittent sealing and conduction to the inlets of the three sets of heat exchange tubes 12. Combined with the reciprocating blocking action of the sealing plug 18, it achieves dynamic adjustment of the flue gas flow rate, velocity, and residence time within the heat exchange tubes 12, preventing incomplete heat exchange due to excessively high flue gas velocity. The linkage between the sealing plate 30 and the sealing plug 18, combined with the diversion structure of the diversion pipe 13 and the temporary storage pipe 16, effectively breaks the low-temperature boundary layer formed by radial temperature stratification inside the heat exchange tubes 12, weakens the adverse effects of near-wall low-temperature flue gas on the heat exchange process, maximizes the extraction and utilization of heat from the central high-temperature flue gas, and significantly improves the waste heat grade and overall recovery efficiency of low-quality sintering flue gas.

[0037] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A waste heat upgrading system for low-quality sintering flue gas, comprising a heat exchanger shell (1), characterized in that: The heat exchanger shell (1) is equipped with three sets of heat exchange tubes (12) for introducing flue gas, and the three sets of heat exchange tubes (12) are arranged in a ring. A flow-dividing assembly is also installed on the heat exchange tube (12). The flow-dividing assembly includes a flow-dividing tube (13) and a temporary storage tube (16). The flow-dividing tube (13) and the temporary storage tube (16) are respectively installed at the end of the heat exchange tube (12). The inner cavities of the flow-dividing tube (13) and the temporary storage tube (16) are connected to the inner cavity of the heat exchange tube (12). The inlet of the flow-dividing tube (13) corresponds to the side wall of the inner cavity of the heat exchange tube (12) and is used to guide the gas that has completed heat exchange to be discharged. The temporary storage tube (16) corresponds to the center of the heat exchange tube (12) and is used to guide the gas that has not completed heat exchange in the center to flow to the temporary storage tube (16) for heat exchange. The inlet of the temporary storage tube (16) is provided with a barrier chamber (17), and the barrier chamber (17) is conical. A sealing plug (18) is inserted into the barrier chamber (17). The sealing plug (18) is used to block the flow of gas and to improve the heat exchange time of the gas inside the temporary storage tube (16). A sealing plate (30) is rotatably installed at the inlet of the three sets of heat exchange tubes (12). The sealing plate (30) is fan-shaped and the central angle of the sealing plate (30) is 150°. The sealing plate (30) is used to gap seal the corresponding heat exchange tube (12). A drive assembly for driving the movement of the sealing plate (30) and the sealing plug (18) is also installed between them.

2. The low-quality sintering flue gas waste heat upgrading system according to claim 1, characterized in that, A fixing block (2) is installed on the back of the heat exchanger shell (1). A fixing plate (3) is installed at the end of the fixing block (2). The fixing block (2) and the fixing plate (3) are T-shaped. Four fixing holes (5) are installed at the corner of the fixing plate (3). Several pairs of reinforcing members (4) are installed at the connection between the fixing plate (3) and the fixing block (2). The reinforcing members (4) are triangular.

3. The low-quality sintering flue gas waste heat upgrading system according to claim 1, characterized in that, The heat exchanger housing (1) is equipped with end covers (9) at both ends. One end cover (9) has three through holes (31) and the corresponding through holes (31) are connected to the side wall of the heat exchange tube (12). The other end cover (9) is also equipped with a drive assembly and is also connected to the diversion tube (13) and the temporary storage tube (16).

4. A low-quality sintering flue gas waste heat upgrading system according to claim 3, characterized in that, The heat exchanger shell (1) is equipped with an inlet pipe (6) at one end and an outlet pipe (7) at the other end. Both the inlet pipe (6) and the outlet pipe (7) are bent. The inlet pipe (6) and the outlet pipe (7) are integrally cast with the heat exchanger shell (1). The height of the inlet pipe (6) is lower than the height of the outlet pipe (7). The inlet pipe (6) is located on the side where the heat exchange tube (12) is installed, and the outlet pipe (7) is installed on the other side.

5. A low-quality sintering flue gas waste heat upgrading system according to claim 4, characterized in that, An air inlet pipe (10) is installed on the end cover (9) which is connected to one end of the heat exchange pipe (12), and an air outlet pipe (11) is installed on the end cover (9) which is connected to one end of the diversion pipe (13). The air inlet pipe (10), the air outlet pipe (11), the water inlet pipe (6) and the water outlet pipe (7) are all integrally cast with a connecting flange (8), and the connecting flange (8) is provided with a connecting hole for easy connection.

6. A low-quality sintering flue gas waste heat upgrading system according to claim 1, characterized in that, The diversion pipe (13) is located outside the temporary storage pipe (16). A diversion cavity (15) is provided on the diversion pipe (13). A notch (14) is provided on the diversion pipe (13). The notch (14) is used to make the inner cavity of the heat exchanger shell (1) contact the outer wall of the temporary storage pipe (16).

7. A low-quality sintering flue gas waste heat upgrading system according to claim 3, characterized in that, The drive assembly includes a turntable (20), and a drive motor (21) is installed on the outer wall of the end cover (9). The output end of the drive motor (21) is connected to the end cover (9), and the output end of the drive motor (21) is connected to the turntable (20). The turntable (20) is placed on the communicating cavity (28) opened inside the end cover (9).

8. A low-quality sintering flue gas waste heat upgrading system according to claim 7, characterized in that, The turntable (20) is equipped with a synchronous shaft (29) at its rotation center. The synchronous shaft (29) is movably connected to the side walls of the two end covers (9). The end of the synchronous shaft (29) is connected to the rotation center of the sealing plate (30), and the sealing plate (30) is made of rubber.

9. A low-quality sintering flue gas waste heat upgrading system according to claim 7, characterized in that, A protrusion (22) is installed on the turntable (20), and both ends of the protrusion (22) are chamfered. The central angle of the protrusion (22) corresponds to the central angle of the sealing plate (30). A synchronizing rod (19) is slidably installed on the protrusion (22), and the end of the synchronizing rod (19) is connected to the end of the sealing plug (18). The synchronizing rod (19) moves through the temporary storage tube (16). A reset seat (26) is slidably installed on the synchronizing rod (19), and the reset seat (26) is installed on the side wall of the end cover (9). The synchronizing rod (19) A baffle (24) is installed on the synchronous rod (19), and a reset spring (25) is sleeved on the synchronous rod (19). One end of the reset spring (25) is clamped on the baffle (24), and the other end of the reset spring (25) is clamped on the side wall of the reset seat (26). A ball (23) is installed at the end of the synchronous rod (19), and the reset spring (25) is used to drive the ball (23) to fit against the side wall of the protrusion (22). A rib (27) is installed on the reset seat (26), and the rib (27) is installed in the inner cavity of the end cover (9).

10. A method for improving the quality of low-quality sintering flue gas using waste heat, characterized in that, The low-quality sintering flue gas waste heat upgrading system according to any one of claims 1 to 9, and the method for upgrading low-quality sintering flue gas waste heat, comprises the following steps: Step 1: Dust-laden low-quality sintering flue gas enters the end cover (9) through the inlet pipe (10). Under the guidance and gap control of the sealing plate (30), it enters the heat exchange tubes (12) arranged in a ring inside the heat exchanger shell (1). The external heat exchange medium water enters the heat exchanger shell (1) through the lower water inlet pipe (6) and forms a counter-current flow heat exchange with the flue gas in the heat exchange tubes (12). The medium heated by heat exchange is discharged through the higher water outlet pipe (7), realizing the initial recovery of low-quality waste heat. Step 2: During the flow of flue gas in the heat exchange tube (12), the low-temperature flue gas near the tube wall and the high-temperature flue gas in the central area form a radial temperature stratification. The low-temperature flue gas near the tube wall and which has completed heat exchange enters the diversion tube (13) along the side wall of the heat exchange tube (12), while the high-temperature flue gas in the central area, which has not been sufficiently heat-exchanged, enters the temporary storage tube (16), thus realizing the diversion and guidance of high and low temperature flue gas. Step 3: The drive motor (21) drives the turntable (20) to rotate. The protrusion (22) on the turntable (20) cooperates with the ball (23) to drive the synchronous rod (19) to move axially, so that the sealing plug (18) reciprocates in the conical barrier chamber (17). When the sealing plug (18) is inserted into the barrier chamber (17), the high-temperature flue gas in the temporary storage tube (16) is blocked and retained, extending the heat exchange time to achieve deep heat exchange and quality improvement. Step 4: The turntable (20) drives the sealing plate (30) to rotate synchronously through the synchronous shaft (29). The fan-shaped sealing plate (30) performs intermittent sealing and conduction on the inlet of the three sets of heat exchange tubes (12). With the blocking action of the sealing plug (18), the flue gas flow rate, velocity and residence time are dynamically adjusted to avoid incomplete heat exchange. Step 5: When the sealing plug (18) exits the barrier chamber (17), the flue gas that has completed sufficient heat exchange and upgrading in the temporary storage tube (16) merges into the diversion tube (13), and after merging with the low-temperature flue gas in the diversion tube (13), it is discharged through the outlet tube (11) to complete the entire process of heat upgrading and upgrading of low-quality sintering flue gas.

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