Primary air steam air preheater

Abstract

The application discloses a primary air steam air preheater and relates to the technical field of steam air preheaters, which comprises a preheater main body installed on a boiler, high-temperature condensate water transmission pipes and low-temperature condensate water transmission pipes connected to the preheater main body, a high-pressure steam section, a low-pressure steam section, a high-pressure supercooling section and a low-pressure supercooling section sequentially arranged in the preheater main body, one end of the high-temperature condensate water transmission pipes being fixedly connected with the high-pressure steam section and the other end being fixedly connected with the high-pressure supercooling section. In the application, high-temperature condensate water is heat-preserved through a heat exchanger, and primary air is preheated with low-temperature air, so that the energy efficiency is improved. The primary air enters the preheater main body through a primary air input pipe, is heated in sequence through the low-pressure supercooling section, the high-pressure supercooling section, the low-pressure steam section and the high-pressure steam section, and the temperature of the primary air is gradually increased, so that the heating process is more reasonable, the heat of each section is fully utilized, the primary air finally reaches the required temperature, and the requirement of the next process is met.

Description

Technical Field

[0001] This invention relates to the field of steam-air preheater technology, specifically a primary air steam-air preheater. Background Technology

[0002] An air preheater is a heat exchange surface device that preheats the air entering the boiler to a certain temperature. It can improve the boiler's heat exchange performance and reduce energy consumption. It uses the waste heat of steam to preheat the primary air, making the fuel burn more completely, thereby improving the boiler's thermal efficiency.

[0003] Before the air preheater heats the primary air with steam, it is common practice to preheat the primary air first in order to improve heat exchange efficiency. Since the steam will produce condensate after the heat exchange with the primary air, and the condensate has residual heat, the residual heat of the condensate is often used directly to preheat the primary air. The air preheater will introduce steam with different temperatures to exchange heat with the primary air in stages. The condensate produced after heat exchange by steam with a lower temperature is at a different temperature than that of high-temperature steam. In particular, the condensate with a lower temperature is already relatively cold. During the process of being transported to the primary air preheating position, the residual heat will gradually dissipate, resulting in poor preheating effect on the primary air. Summary of the Invention

[0004] The purpose of this invention is to provide a primary air steam preheater to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides a primary air steam preheater, including a preheater body installed on a boiler, and a high-temperature condensate transmission pipe and a low-temperature condensate transmission pipe connected to the preheater body. The preheater body is divided into a high-pressure steam section, a low-pressure steam section, a high-pressure subcooling section, and a low-pressure subcooling section in sequence. One end of the high-temperature condensate transmission pipe is fixedly connected to the high-pressure steam section and the other end is fixedly connected to the high-pressure subcooling section. One end of the low-temperature condensate transmission pipe is fixedly connected to the low-pressure steam section and the other end is fixedly connected to the low-pressure subcooling section. A high-pressure steam pipe is connected to one side of the high-pressure steam section, a low-pressure steam pipe is connected to one side of the low-pressure steam section, a gas guide pipe is connected to the top of the high-pressure steam section, and a primary air input pipe is connected to one side of the low-pressure subcooling section. A heat exchanger is installed at the adjacent point of the high-temperature condensate transfer pipe and the low-temperature condensate transfer pipe to transfer a portion of the high temperature of the high-temperature condensate transfer pipe to the low-temperature condensate transfer pipe.

[0006] Furthermore, the end of the high-temperature condensate transmission pipe connected to the high-pressure subcooling section is close to the connection between the low-pressure steam section and the high-pressure subcooling section, the end of the low-temperature condensate transmission pipe connected to the low-pressure subcooling section is close to the connection between the low-pressure subcooling section and the high-pressure subcooling section, and the end of the primary air input pipe connected to the low-pressure subcooling section is located on the side of the low-pressure subcooling section away from the high-pressure subcooling section.

[0007] Furthermore, both the low-pressure subcooling section and the high-pressure subcooling section are equipped with heat exchange tubes for transporting condensate, and the heat exchange tubes are spiraled along the axis of the low-pressure subcooling section.

[0008] Furthermore, the inlet of the heat exchange tube is called the inlet end, the bend of the heat exchange tube corresponding to the inlet end is called the bend end, and a parallel transverse segment is formed between the inlet end and the bend end.

[0009] Furthermore, the horizontal section bends towards the direction of the primary air inlet pipe to form an arc surface, with a height difference between the bend end and the inlet end, and the inlet end being higher than the bend end.

[0010] Furthermore, the transverse section within the low-pressure subcooling section is located near the connection between the low-pressure subcooling section and the high-pressure subcooling section, and the transverse section within the high-pressure subcooling section is located near the connection between the high-pressure subcooling section and the low-pressure steam section.

[0011] Furthermore, the primary air inlet pipe is inclined away from the inlet of the low-pressure subcooling section, forming a laterally inclined oblique opening. Furthermore, the central axis of the primary air inlet pipe overlaps with the central axis of the low-pressure subcooling section, and the end of the primary air inlet pipe that connects to the low-pressure subcooling section corresponds to the outer wall of the heat exchange tube.

[0012] Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, high-temperature condensate retains heat through a heat exchanger to heat low-temperature condensate, reducing the temperature difference to achieve balanced heat transfer. Primary air enters the preheater body through the primary air input pipe and is heated sequentially through a low-pressure subcooling section, a high-pressure subcooling section, a low-pressure steam section, and a high-pressure steam section, gradually increasing the primary air temperature. This makes the heating process more efficient, fully utilizes the heat from each section, and ensures that the primary air eventually reaches the required temperature to meet the needs of the next process.

[0013] 2. In this invention, the primary air input pipe is connected to the bottom of the low-pressure subcooling section, which sends the primary air into the preheater body. The air is then preheated in the low-pressure subcooling section, heated in the high-pressure subcooling section, heated in the low-pressure steam section and the high-pressure steam section, and finally sent to the next process through the air guide pipe. This allows the primary air to be heated in multiple stages, resulting in a more stable and sufficient temperature rise. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the internal structure of the present invention; Figure 2This is a schematic diagram of the internal structure of the high-temperature condensate transfer pipe and the low-temperature condensate transfer pipe in this invention; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 for Figure 2 Enlarged view of point B in the middle; Figure 5 This is a cross-sectional schematic diagram of the high-temperature condensate transfer pipe and the low-temperature condensate transfer pipe in this invention. Figure 6 for Figure 5 Enlarged view of point C in the middle; Figure 7 This is a schematic diagram of the connection structure between the high-temperature condensate transmission pipe and the connecting pipe in this invention; Figure 8 This is a schematic cross-sectional view of the low-temperature condensate transmission pipe in this invention; Figure 9 This is a schematic diagram of the connection structure between the connecting pipe and the through groove in this invention; Figure 10 This is a schematic diagram of the connection structure between the outer shell and the heat exchanger in this invention; Figure 11 This is a schematic diagram of the connection structure between the outer shell and the extension plate in this invention; Figure 12 This is a schematic diagram of the connection structure between the heat exchanger and the fixing rod in this invention; Figure 13 This is a schematic diagram of the connection structure between the fins and the water passage gap in this invention; Figure 14 This is a schematic diagram of the connection structure between the frame and the fins in this invention; Figure 15 This is a schematic diagram of the connection structure between the low-pressure subcooling section and the heat exchange tube in this invention; Figure 16 This is a schematic diagram of the connection structure between the primary air input pipe and the oblique opening in this invention.

[0015] In the diagram: 1. Preheater body; 101. Heat exchange tube; 102. Inlet end; 103. Bend end; 104. Horizontal section; 2. Low-pressure steam pipe; 3. High-pressure steam pipeline; 4. Primary air inlet pipe; 401. Slanted inlet; 5. Steam guide pipe; 6. High-pressure steam section; 7. Low-pressure steam section; 8. High-pressure subcooling section; 9. Low-pressure subcooling section; 10. High-temperature condensate transfer pipe; 11. Low-temperature condensate transfer pipe; 12. Connecting pipe; 13. Transmission rod; 14. Water impeller; 15. Outer casing; 16. Heat exchanger; 161. Frame; 162. Fins; 163. Water passage gap; 17. Extension plate; 18. Inner cavity; 19. Slot; 20. Opening; 21. Heat exchange plate; 22. Chamber; 23. Through slot; 24. Fixing rod; 25. Slot. Detailed Implementation

[0016] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] This invention provides a technical solution: See Figures 1-15 As shown, it includes a preheater body 1 installed on a boiler, and also includes a high-temperature condensate transmission pipe 10 and a low-temperature condensate transmission pipe 11 connected to the preheater body 1. The preheater body 1 is divided into a high-pressure steam section 6, a low-pressure steam section 7, a high-pressure subcooling section 8, and a low-pressure subcooling section 9 in sequence. One end of the high-temperature condensate transmission pipe 10 is fixedly connected to the high-pressure steam section 6 and the other end is fixedly connected to the high-pressure subcooling section 8. One end of the low-temperature condensate transmission pipe 11 is fixedly connected to the low-pressure steam section 7 and the other end is fixedly connected to the low-pressure subcooling section 9. A high-pressure steam pipe 3 is connected to one side of the high-pressure steam section 6, a low-pressure steam pipe 2 is connected to one side of the low-pressure steam section 7, a gas guide pipe 5 is connected to the top of the high-pressure steam section 6, and a primary air input pipe 4 is connected to one side of the low-pressure subcooling section 9. A heat exchanger 16 is provided at the adjacent position of the high-temperature condensate transfer pipe 10 and the low-temperature condensate transfer pipe 11 to transfer a portion of the high temperature of the high-temperature condensate transfer pipe 10 to the low-temperature condensate transfer pipe 11.

[0018] The high-temperature condensate transfer pipe 10 is used to transfer condensate from high-pressure steam, and the low-temperature condensate transfer pipe 11 is used to transfer condensate from low-pressure steam. The temperature of the condensate in the high-temperature condensate transfer pipe 10 is higher than that of the condensate in the low-temperature condensate transfer pipe 11. Therefore, the condensate in the low-temperature condensate transfer pipe 11 is transferred to the place where it first comes into contact with the primary air for initial preheating. The condensate in the high-temperature condensate transfer pipe 10, which has a slightly higher temperature, is used for further heating after the initial preheating of the primary air. Since there is a large temperature difference between the two, when the high-temperature condensate is transferred in the high-temperature condensate transfer pipe 10, it passes through the heat exchanger 16, where the heat is retained. Then, the heat exchanger 16 transfers the heat to the low-temperature condensate in the low-temperature condensate transfer pipe 11 to heat the low-temperature condensate in the low-temperature condensate transfer pipe 11. First, slightly raising the temperature of the low-temperature condensate prevents it from losing heat too quickly during transport. This also reduces the temperature difference between the low-temperature and high-temperature condensates. If the temperature difference is too large, a large amount of heat from the high-temperature condensate will be released rapidly in a short time. Because a greater temperature difference results in a faster heat transfer rate, the following situation may occur: On the one hand, the air temperature after preheating the low-temperature condensate is too low, and the heat of the high-temperature condensate cannot be fully utilized; on the other hand, the high-temperature condensate releases heat rapidly, causing its own temperature to drop sharply, and it cannot fully utilize the waste heat value of secondary heating. After reducing the temperature difference, the heat transfer between the two types of condensate is more balanced. The low-temperature condensate first raises the air temperature to a range close to that of the high-temperature condensate, and then the high-temperature condensate takes over the heating. This allows the waste heat of both to be transferred more fully to the primary air, reducing the waste of excess waste heat from the high-temperature condensate or insufficient preheating of the low-temperature condensate, and reducing the heat replenishment pressure of subsequent steam heating. At the same time, after reducing the temperature difference, when the primary air enters the high-temperature condensate heating stage, its temperature is closer to that of the high-temperature condensate, and the temperature gradient inside the equipment is gentler, which can reduce the damage to the equipment caused by thermal shock. The primary air inlet pipe 4 is fixedly connected to the bottom end of the low-pressure subcooling section 9, and is used to first deliver primary air into the low-pressure subcooling section 9. The low-pressure steam pipe 2 is fixedly connected to the low-pressure steam section 7, and is used to deliver low-pressure steam into the low-pressure steam section 7. The high-pressure steam pipeline 3 is fixedly connected to the high-pressure steam section 6 and is used to transport high-pressure steam to the high-pressure steam section 6. After the primary air enters the preheater body 1, it passes through the low-pressure subcooling section 9 for preheating, and then enters the high-pressure subcooling section 8 for further heating. After that, it enters the low-pressure steam section 7 to be formally heated by low-pressure steam. At this time, the steam temperature will not be too high. Finally, it enters the high-pressure steam section 6 to be heated by high-temperature steam. After the heating is completed, it is transported to the next process through the air guide pipe 5. The preheater body 1 is also equipped with a condensate drainage system. The condensate drainage system consists of a condensate drainage device body, instruments, valves, regulating valves, etc. The condensate drainage device is equipped with a steam balance valve. The condensate from the steam section flows into the condensate drainage device by gravity. During operation, after the high-pressure steam undergoes heat exchange, the condensate enters the high-pressure condensate drainage device. The outlet of the high-pressure condensate drainage device enters the high-pressure subcooling section 8. The outlet of the high-pressure subcooling section 8 is equipped with a high-pressure condensate drainage regulating valve group. The high-pressure side condensate drainage regulating valve is linked with the liquid level on the high-pressure condensate drainage device to control the constant liquid level of the condensate in the high-pressure condensate drainage device. When the liquid level is higher than the set value, the valve will automatically open wider; when the liquid level is lower than the design value, the valve will automatically close narrower. During operation, after the low-pressure steam undergoes heat exchange, the condensate enters the low-pressure condensate drain device. The effluent from the low-pressure condensate drain device enters the low-pressure subcooling section 9. The outlet of the low-pressure subcooling section 9 is equipped with a low-pressure condensate drain regulating valve group. The low-pressure side condensate drain regulating valve is linked to the liquid level on the low-pressure condensate drain device to control the constant liquid level of the condensate in the low-pressure condensate drain device. When the liquid level is higher than the set value, the valve will automatically open wider; when the liquid level is lower than the design value, the valve will automatically close narrower. The high-pressure and low-pressure condensate drain devices are controlled by PID. The device is equipped with a specific water level control device. The liquid level in the condensate drain device must be higher than the outlet height. The pressure and temperature signals on the condensate drain pipe are only used for display on the host computer panel and have no logic control. Alternatively, the temperature signal can be used for high-temperature alarm. An alarm will be triggered when the condensate drain temperature reaches the saturation pressure of the high-pressure condensate drain header.

[0019] See Figure 1 As shown, the end of the high-temperature condensate transmission pipe 10 connected to the high-pressure subcooling section 8 is close to the connection between the low-pressure steam section 7 and the high-pressure subcooling section 8. The end of the low-temperature condensate transmission pipe 11 connected to the low-pressure subcooling section 9 is close to the connection between the low-pressure subcooling section 9 and the high-pressure subcooling section 8. The end of the primary air input pipe 4 connected to the low-pressure subcooling section 9 is located on the side of the low-pressure subcooling section 9 away from the high-pressure subcooling section 8.

[0020] The high-temperature condensate transfer pipe 10 transmits high-temperature condensate at one end near the connection between the high-pressure subcooling section 8 and the low-pressure steam section 7, making the temperature here even higher. This further reduces the temperature difference between the high-pressure subcooling section 8 and the low-pressure steam section 7. The high-temperature condensate entering the high-pressure subcooling section 8 through the high-temperature condensate transfer pipe 10 circulates from the top of the high-pressure subcooling section 8 to the bottom of the high-pressure subcooling section 8, making the temperature at the bottom of the high-pressure subcooling section 8 lower than the temperature at the top of the high-pressure subcooling section 8. Similarly, the low-temperature condensate transfer pipe 11 transmits low-temperature condensate at one end near the connection between the low-pressure subcooling section 9 and the high-pressure subcooling section 8, making the low-temperature condensate entering the low-pressure subcooling section 9 through the low-temperature condensate transfer pipe 11 circulate from the top of the low-pressure subcooling section 9 to the bottom of the low-pressure subcooling section 9, making the temperature at the bottom of the low-pressure subcooling section 9 lower than the temperature at the top of the low-pressure subcooling section 9. The primary wind moves from bottom to top, further enhancing the stepped preheating effect of the primary wind and resulting in a more gradual temperature rise.

[0021] See Figure 15 As shown, both the low-pressure subcooling section 9 and the high-pressure subcooling section 8 are equipped with heat exchange tubes 101 for transferring condensate. The heat exchange tubes 101 are spiraled along the axis of the low-pressure subcooling section 9.

[0022] The spiral shape of the heat exchange tube 101 increases the contact area with the primary air, further improving the preheating effect.

[0023] See Figure 15 As shown, the inlet of the heat exchange tube 101 is the inlet end 102, and the bend of the heat exchange tube 101 corresponding to the inlet end 102 is the bend end 103. A parallel transverse segment 104 is formed between the inlet end 102 and the bend end 103.

[0024] Both the low-pressure subcooling section 9 and the high-pressure subcooling section 8 are equipped with heat exchange tubes 101. The inlet of the heat exchange tube 101, that is, the inlet end 102, is close to the top of the high-pressure subcooling section 8 and the low-pressure subcooling section 9, respectively. The inlet end 102 in the high-pressure subcooling section 8 corresponds to the end of the high-temperature condensate transmission pipe 10 connected to the high-pressure subcooling section 8, and then the high-temperature condensate enters the heat exchange tube 101 in the high-pressure subcooling section 8. The inlet end 102 in the low-pressure subcooling section 9 corresponds to the end of the low-temperature condensate transmission pipe 11 connected to the low-pressure subcooling section 9, and is used for the low-temperature condensate to enter the heat exchange tube 101 in the low-pressure subcooling section 9. The lower horizontal section 104 is close to the high-pressure subcooling section 8, so it is set to be parallel, which slows down the flow of condensate and allows the heat to be retained for a longer time, further reducing the temperature difference between the high-pressure subcooling section 8 and the low-pressure subcooling section 9. The horizontal section 104 in the high-pressure subcooling section 8 is also close to the low-pressure subcooling section 9, reducing the temperature difference between the high-pressure subcooling section 8 and the low-pressure steam section 7, and providing a more stable initial air temperature for subsequent heating stages.

[0025] See Figure 15 As shown, the horizontal section 104 bends in the direction of the primary air input pipe 4 to form an arc surface. There is a height difference between the bending end 103 and the inlet end 102, with the inlet end 102 being higher than the bending end 103.

[0026] The horizontal section 104 bends slightly downwards, creating a low-lying area where the water flows, further reducing the downward flow speed of the condensate and allowing the condensate to remain at the junction for a longer period. At the same time, the bend end 103 is lower than the inlet end 102, so the left end of the horizontal section 104 still has a slight downward tilt angle, preventing the water from flowing back. Instead, the water will flow along the horizontal section 104 to the bend end 103 and then across the bend end 103 to the lower end of the heat exchange tube 101.

[0027] See Figures 15-16 As shown, the transverse section 104 in the low-pressure subcooling section 9 is close to the connection between the low-pressure subcooling section 9 and the high-pressure subcooling section 8, and the transverse section 104 in the high-pressure subcooling section 8 is close to the connection between the high-pressure subcooling section 8 and the low-pressure steam section 7.

[0028] The two horizontal segments 104 are respectively close to the low-pressure subcooling section 9 and the high-pressure subcooling section 8, and the high-pressure subcooling section 8 and the low-pressure steam section 7, so that the temperature between the low-pressure subcooling section 9 and the high-pressure subcooling section 8, and the high-pressure subcooling section 8 and the low-pressure steam section 7 is higher, thus reducing the temperature difference.

[0029] See Figures 15-16 As shown, the primary air inlet pipe 4 is inclined away from the inlet of the low-pressure subcooling section 9, forming a laterally inclined slanted opening 401.

[0030] The primary air inlet pipe 4 is used for the entry of primary air. The oblique opening 401 can change the flow direction of the primary air entering the heating area, avoid the air blowing directly onto the inner wall of the equipment, and allow the air to diffuse more evenly into the heating space, thereby improving the heat exchange efficiency.

[0031] See Figure 15 As shown, the central axis of the primary air inlet pipe 4 overlaps with the central axis of the low-pressure subcooling section 9, and the end of the primary air inlet pipe 4 that connects to the low-pressure subcooling section 9 corresponds to the outer wall of the heat exchange tube 101.

[0032] The primary air inlet pipe 4 corresponds to the central area of ​​the low-pressure subcooling section 9. After the primary air enters, it can be evenly distributed in the low-pressure subcooling section 9. After the primary air enters the low-pressure subcooling section 9, it will directly contact the heat exchange tube 101 and be heated.

[0033] To improve the heat exchange effect of heat exchanger 16: a transmission rod 13 is provided at the intersection of high-temperature condensate transmission pipe 10 and low-temperature condensate transmission pipe 11. A water wheel 14 is fixedly installed at the top of the transmission rod 13. The heat exchanger 16 is located at the intersection of high-temperature condensate transmission pipe 10 and low-temperature condensate transmission pipe 11. The transmission rod 13 is rotatably connected to the high-temperature condensate transmission pipe 10. The heat exchanger 16 includes a frame 161. The frame 161 is connected to the fixed transmission rod 13. The frame 161 is divided into multiple cavities by partitions. Multiple fins 162 are fixedly installed on the inner wall of the cavity. The multiple fins 162 are spaced apart, with water passage gaps 163 between them for water supply.

[0034] Please read first. Figure 2 The high-temperature condensate transfer pipe 10 is used to transfer the condensate of high-pressure steam, and the low-temperature condensate transfer pipe 11 is used to transfer the condensate of low-pressure steam. The temperature of the condensate in the high-temperature condensate transfer pipe 10 is higher than that of the condensate in the low-temperature condensate transfer pipe 11. First, the vertical section of the high-temperature condensate transfer pipe 10 passes through the low-temperature condensate transfer pipe 11, and the high-temperature condensate transfer pipe 10 and the low-temperature condensate transfer pipe 11 are fixed together. When high-temperature condensate is transferred within the high-temperature condensate transfer pipe 10, the water passes through the area within the low-temperature condensate transfer pipe 11 after passing through the high-temperature condensate transfer pipe 10. Then please see... Figure 3 The heat exchanger 16 is positioned horizontally between the high-temperature condensate transfer pipe 10 and the low-temperature condensate transfer pipe 11. The center of the heat exchanger 16 is enclosed by the body of the high-temperature condensate transfer pipe 10. The transmission rod 13 is connected to the heat exchanger 16, and the top of the transmission rod 13 is connected to the water wheel 14. The water wheel 14 is located in the channel area inside the high-temperature condensate transfer pipe 10. After the condensate impacts the water wheel 14 from top to bottom, the water wheel 14 rotates. The rotation of the water wheel 14 will drive the transmission rod 13 to rotate together, and then drive the heat exchanger 16 to rotate through the transmission rod 13, so that multiple fins 162 inside the heat exchanger 16 alternately enter the low-temperature condensate transfer pipe 11 and the high-temperature condensate transfer pipe 10. When the condensate in the high-temperature condensate transfer pipe 10 flows, it comes into contact with the fins 162, and the heat remains on the fins 162. Then the water falls through the water passage gap 163 and continues to complete the transfer. The continuously rotating heat exchanger 16 rotates the fins 162 that are in contact with the high-temperature condensate into the low-temperature condensate transfer pipe 11. The low-temperature condensate in the low-temperature condensate transfer pipe 11 comes into contact with the fins 162 that still have heat. Then some of the low-temperature condensate also passes through the water passage gap 163, carrying away the heat on the fins 162, thus achieving heat transfer to the low-temperature condensate.

[0035] See Figures 2-10 As shown, a narrowed connecting pipe 12 is formed at the intersection of the high-temperature condensate transfer pipe 10 and the low-temperature condensate transfer pipe 11. The diameter of the connecting pipe 12 is smaller than that of the high-temperature condensate transfer pipe 10. The connecting pipe 12 is located inside the low-temperature condensate transfer pipe 11. The heat exchanger 16 is rotatably connected to the edge of the connecting pipe 12. Part of the heat exchanger 16 is located inside the connecting pipe 12, and another part is located inside the low-temperature condensate transfer pipe 11.

[0036] exist Figure 8 As can be clearly seen, the diameter of the connecting pipe 12 is smaller than that of the high-temperature condensate transmission pipe 10. The connecting pipe 12 is located inside the low-temperature condensate transmission pipe 11. After the water passes through the connecting pipe 12, due to the narrowing of the channel, the water at the top of the connecting pipe 12 will concentrate and accelerate, which is conducive to the water impacting the water wheel 14 to make it rotate. At the same time, the acceleration of the water can also pass through the water passage gap 163 more quickly. This allows the heat of the subsequent water to be quickly retained on the fins 162, avoiding the water in the same area from staying in the water passage gap 163 for too long and causing excessive heat loss. Meanwhile, the fins 162 inside the heat exchanger 16 are arranged densely and form lateral shielding between each other. This prevents the water in the high-temperature condensate transfer pipe 10 and the low-temperature condensate transfer pipe 11 from being connected in series too much. There is no situation where the water in the high-temperature condensate transfer pipe 10 flows directly into the low-temperature condensate transfer pipe 11 through the heat exchanger 16. The dense arrangement of the fins 162 can also retain more heat to be transferred to the low-temperature condensate.

[0037] See Figures 3-10 As shown, the connecting pipe 12 has a through groove 23, and the inner wall of the through groove 23 is fixedly installed with the outer shell 15. The heat exchanger 16 is rotatably connected to the outer shell 15. The inner top wall of the through groove 23 is in close contact with the top of the outer shell 15 and the heat exchanger 16, and the inner bottom wall of the through groove 23 is in close contact with the bottom of the outer shell 15 and the heat exchanger 16. The heat exchanger 16 is located at the corner of the low temperature condensate transmission pipe 11.

[0038] Please see Figure 6The connecting pipe 12 passes through the through groove 23 and communicates with the low-temperature condensate transmission pipe 11 and the connecting pipe 12. The heat exchanger 16 is located inside the through groove 23, and the center of the heat exchanger 16 and the transmission rod 13 are also located inside the through groove 23. In this way, the heat exchanger 16 can rotate between the low-temperature condensate transmission pipe 11 and the connecting pipe 12 with the through groove 23 as the rotation point. Figure 10 The outer casing 15 is fixedly installed in the through groove 23, and the outer casing 15 encloses the heat exchanger 16 therein, and the heat exchanger 16 rotates inside the outer casing 15; The inner wall of the outer casing 15 is elastic, adapting to the friction caused by the rotation of the heat exchanger 16, and can continuously fit in contact with the heat exchanger 16.

[0039] See Figure 6 As shown, the connecting pipe 12 has a slot 19, and the transmission rod 13 is rotatably connected in the slot 19. The top end of the transmission rod 13 extends vertically into the high-temperature condensate transmission pipe 10 and is fixedly connected to the water wheel 14. A fixing rod 24 is fixedly installed on the outer wall of the transmission rod 13 in the through groove 23. The fixing rod 24 is located in the middle of the through groove 23. The inner wall of the frame 161 is fixedly connected to the outer wall of the transmission rod 13. The top and bottom of the frame 161 are flush with the top and bottom of the heat exchanger 16.

[0040] The slot 19 is opened on the connecting pipe 12 to provide a space for the transmission rod 13. After the water wheel 14 drives the transmission rod 13 to rotate, the transmission rod 13 rotates in the slot 19. The fixing rod 24 is fixedly installed on the outer wall of the transmission rod 13. The top end of the fixing rod 24 abuts against the inner top wall of the through groove 23, and the bottom end of the fixing rod 24 abuts against the inner bottom wall of the through groove 23. The frame 161 is fixedly connected to the outer wall of the fixing rod 24. After the transmission rod 13 rotates, it first drives the fixing rod 24 to rotate, and then drives the entire heat exchanger 16 to rotate through the fixing rod 24.

[0041] See Figure 14 As shown, the fins 162 are inclined to form water passage gaps 163 with the same inclination angle. The fins 162 are integrally formed into a curved shape. The cavity of the frame 161 is open from top to bottom. The water passage gaps 163 extend from the top to the bottom of the heat exchanger 16.

[0042] The corrugated fins 162 have a larger unfolded area than the flat ones within the same volume or installation space, thereby increasing the contact opportunity with condensate and improving heat exchange efficiency. At the same time, the inclined fins 162 have the agitation effect of the impeller rotation, which accelerates heat exchange.

[0043] See Figures 3-11As shown, an extension plate 17 is fixedly installed at the bottom of the outer shell 15. The extension plate 17 extends toward the inner bottom wall of the low-temperature condensate transfer pipe 11. The two side walls of the extension plate 17 are fixedly connected to the inner wall of the low-temperature condensate transfer pipe 11 to form an inner cavity 18. The top of the inner cavity 18 corresponds to a part of the bottom area of ​​the heat exchanger 16.

[0044] The extension plate 17 extends downward toward the heat exchanger 16, please see... Figure 11 and Figure 12 When the heat exchanger 16 transfers heat from the left side to the low-temperature condensate transfer pipe 11 on the right, some of the water in the low-temperature condensate transfer pipe 11 passes through the water gap 163 and enters the inner cavity 18. When the inner cavity 18 is filled with heated water, the continuously rotating heat exchanger 16 agitates the water flow, causing the water at the junction of the inner cavity 18 and the low-temperature condensate transfer pipe 11 to be agitated. In addition, the inclined fins 162 drive the hot water in the inner cavity 18 to surge into the low-temperature condensate transfer pipe 11, that is, the top of the inner cavity 18. This mixes the heated water in the inner cavity 18 with the water in the low-temperature condensate transfer pipe 11, improving the heat exchange effect. Meanwhile, since the water in the inner cavity 18 is directly heated by the fins 162, its temperature is higher. The heat in the inner cavity 18 is transferred to the extension plate 17, causing the extension plate 17 to heat up. During the water transport process in the low-temperature condensate transfer pipe 11, the heated extension plate 17 can continuously transfer heat to it. Even if the heat is similar, it can prevent the temperature of the low-pressure steam condensate in the low-temperature condensate transfer pipe 11 from dropping rapidly.

[0045] See Figures 4-11 As shown, multiple heat exchange plates 21 are fixedly installed on the outer wall of the extension plate 17. A chamber 22 is opened inside the heat exchange plate 21. The extension plate 17 has an opening 20 that communicates with the chamber 22. The opening 20 communicates with the inner cavity 18.

[0046] Water in the inner cavity 18 enters the chamber 22 through the opening 20, and then the heat is transferred to the heat exchange plate 21. Multiple heat exchange plates 21 increase the contact area with the low-temperature steam condensate in the low-temperature condensate transfer pipe 11, further transferring heat to the low-temperature steam condensate in the low-temperature condensate transfer pipe 11, while preventing the temperature of the low-temperature steam condensate in the low-temperature condensate transfer pipe 11 from dropping too quickly. Please see Figure 4 In the middle, the end of the heat exchange plate 21 away from the extension plate 17 is inclined downward, which reduces the downward pressure of the water, while the water quickly slides over the surface of the heat exchange plate 21 and flows down.

[0047] See Figure 9 As shown, the horizontal section of the low-temperature condensate transmission pipe 11 has two vertically corresponding slots 25. The connecting pipe 12 is inserted between the two slots 25, and the inner wall of the slot 25 is fixedly connected to the outer wall of the connecting pipe 12.

[0048] The slot 25 provides space for the installation of the connecting pipe 12. The connecting pipe 12 is fixed in the slot 25 and fixedly connected to it. The size of the slot 25 fits the connecting pipe 12. After the connecting pipe 12 is installed in the slot 25, the high-temperature condensate transmission pipe 10 will hold the slot 25 against the wide diameter parts at the top and bottom of the connecting pipe 12.

Claims

1. A primary air steam preheater, comprising a preheater body (1) mounted on a boiler, characterized in that, It also includes a high-temperature condensate transfer pipe (10) and a low-temperature condensate transfer pipe (11) connected to the preheater body (1). The preheater body (1) is divided into a high-pressure steam section (6), a low-pressure steam section (7), a high-pressure subcooling section (8), and a low-pressure subcooling section (9) in sequence. One end of the high-temperature condensate transmission pipe (10) is fixedly connected to the high-pressure steam section (6) and the other end is fixedly connected to the high-pressure subcooling section (8). One end of the low-temperature condensate transmission pipe (11) is fixedly connected to the low-pressure steam section (7) and the other end is fixedly connected to the low-pressure subcooling section (9). One side of the high-pressure steam section (6) is connected to a high-pressure steam pipe (3), one side of the low-pressure steam section (7) is connected to a low-pressure steam pipe (2), the top of the high-pressure steam section (6) is connected to a gas guide pipe (5), and one side of the low-pressure subcooling section (9) is connected to a primary air input pipe (4). A heat exchanger (16) is provided at the intersection of the high temperature condensate transfer pipe (10) and the low temperature condensate transfer pipe (11) to transfer a portion of the high temperature of the high temperature condensate transfer pipe (10) to the low temperature condensate transfer pipe (11). A transmission rod (13) is provided at the intersection of the high-temperature condensate transmission pipe (10) and the low-temperature condensate transmission pipe (11). A water wheel (14) is fixedly installed at the top of the transmission rod (13). The transmission rod (13) is rotatably connected to the high-temperature condensate transmission pipe (10). The heat exchanger (16) includes a frame (161). The frame (161) is connected to the transmission rod (13). The frame (161) is divided into multiple cavities by a partition. Multiple fins (162) are fixedly installed on the inner wall of the cavity. The multiple fins (162) are spaced apart, with a water passage gap (163) between them for water supply. At the intersection of the high-temperature condensate transfer pipe (10) and the low-temperature condensate transfer pipe (11), a narrow connecting pipe (12) is formed. The diameter of the connecting pipe (12) is smaller than that of the high-temperature condensate transfer pipe (10). The connecting pipe (12) is located inside the low-temperature condensate transfer pipe (11). The heat exchanger (16) is rotatably connected to the edge of the connecting pipe (12). Part of the heat exchanger (16) is located inside the connecting pipe (12), and another part is located inside the low-temperature condensate transfer pipe (11).

2. The primary air steam preheater as described in claim 1, characterized in that: The end of the high-temperature condensate transmission pipe (10) connected to the high-pressure subcooling section (8) is close to the connection between the low-pressure steam section (7) and the high-pressure subcooling section (8). The end of the low-temperature condensate transmission pipe (11) connected to the low-pressure subcooling section (9) is close to the connection between the low-pressure subcooling section (9) and the high-pressure subcooling section (8). The end of the primary air input pipe (4) connected to the low-pressure subcooling section (9) is located on the side of the low-pressure subcooling section (9) away from the high-pressure subcooling section (8).

3. A primary air steam preheater as described in claim 2, characterized in that: Both the low-pressure subcooling section (9) and the high-pressure subcooling section (8) are equipped with heat exchange tubes (101) for transmitting condensate. The heat exchange tubes (101) are spiraled along the axis of the low-pressure subcooling section (9).

4. A primary air steam preheater as described in claim 3, characterized in that: The inlet of the heat exchange tube (101) is the inlet end (102), and the bend of the heat exchange tube (101) corresponding to the inlet end (102) is the bend end (103). A parallel transverse segment (104) is formed between the inlet end (102) and the bend end (103).

5. A primary air steam preheater as described in claim 4, characterized in that: The horizontal section (104) bends in the direction of the primary air inlet pipe (4) to form an arc surface. There is a height difference between the bent end (103) and the inlet end (102), with the inlet end (102) being higher than the bent end (103).

6. A primary air steam preheater as described in claim 5, characterized in that: The transverse section (104) in the low-pressure subcooling section (9) is close to the connection between the low-pressure subcooling section (9) and the high-pressure subcooling section (8), and the transverse section (104) in the high-pressure subcooling section (8) is close to the connection between the high-pressure subcooling section (8) and the low-pressure steam section (7).

7. A primary air steam preheater as described in claim 6, characterized in that: The primary air inlet pipe (4) is inclined away from the inlet of the low-pressure subcooling section (9) to form a laterally inclined opening (401).

8. A primary air steam preheater as described in claim 7, characterized in that: The central axis of the primary air inlet pipe (4) overlaps with the central axis of the low-pressure subcooling section (9), and the end of the primary air inlet pipe (4) connected to the low-pressure subcooling section (9) corresponds to the outer wall of the heat exchange tube (101).

Images