Anti-freezing air cooling island waste heat recovery device

Abstract

This invention relates to the field of waste heat recovery equipment technology, and discloses a freeze-resistant air-cooled island waste heat recovery device, comprising: a heat exchange box, an air inlet pipe connected to the top of the heat exchange box and connected to the exhaust pipe of the steam turbine, and an air outlet pipe connected to one side of the heat exchange box and connected to the steam inlet pipe of the air-cooled island. This invention, by setting up a first heat exchange tube group and a second heat exchange tube group with an asynchronous opening and closing design, uses antifreeze circulating in the first heat exchange tube group to meet winter freeze protection requirements, and softened water circulating in the second heat exchange tube group to meet summer high-efficiency heat exchange requirements. Simultaneously, combined with an electric butterfly valve to differentiate the flow rate of exhaust steam in the air outlet pipe between winter and summer, it solves the problems of a single heat exchange medium being unable to meet both winter and summer operating conditions and the easy freezing of pipelines in winter, while also avoiding the decrease in unit power generation efficiency caused by artificial pressure buildup in summer. This achieves adaptive matching between winter and summer operating conditions, balancing waste heat recovery efficiency and equipment operational safety.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery equipment technology, specifically to a freeze-resistant air-cooled island waste heat recovery device. Background Technology

[0002] Generally speaking, an air-cooled island is a complete set of equipment used in thermal power generating units to cool and condense the exhaust steam after the steam turbine has done its work. Its main function is to condense the low-temperature, low-pressure exhaust steam discharged from the steam turbine into condensate through forced air convection heat exchange, so as to realize the recycling of steam and water. It is especially suitable for power plants in water-scarce areas to save a lot of cooling water. The waste heat recovery device for the air-cooled island is a core auxiliary device used in conjunction with the air-cooled island to recover the low-grade waste heat of the exhaust steam from the steam turbine. Its core function is to extract and utilize the waste heat of the exhaust steam that was originally directly discharged into the atmosphere in the air-cooled island, and convert it into usable heat energy such as heat supply and domestic hot water. At the same time, it helps to regulate the operating pressure and temperature of the air-cooled island, taking into account both energy saving and equipment antifreeze requirements.

[0003] In actual operation, air-cooled tube bundles are prone to freezing and cracking due to excessive cooling in low-temperature winter environments. At the same time, during waste heat recovery, condensate will continuously form on the outer wall of the heat exchange tube bundle, forming a thick water film that increases the heat exchange thermal resistance and reduces the heat recovery efficiency. In winter, ice is also prone to form on the tube wall, further deteriorating the heat exchange effect and damaging the tube bundle. Moreover, existing devices mostly use a single heat exchange pipeline and medium, which cannot meet the requirements of winter antifreeze and high-efficiency heat exchange in summer. Based on this, the present invention aims to provide an antifreeze type air-cooled island waste heat recovery device that can optimize the waste steam heat exchange conditions and remove condensate from the tube wall in a timely manner. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a freeze-proof waste heat recovery device for air-cooled islands, thereby solving the technical problems in the prior art.

[0005] The objective of this invention can be achieved through the following technical solutions: A frost-resistant air-cooled island waste heat recovery device includes: The heat exchange chamber has an air inlet pipe connected to the top, which is connected to the exhaust pipe of the steam turbine. An air outlet pipe is connected to one side of the heat exchange chamber, which is connected to the steam inlet pipe of the air-cooled island. A drain outlet is provided at the bottom of the heat exchange chamber, which is connected to a drain pipe. A solenoid valve is installed on the drain pipe. A first heat exchange tube group and a second heat exchange tube group are arranged through the heat exchange chamber. The first heat exchange tube group and the second heat exchange tube group are arranged side by side and are respectively connected to two external circulation components. Both of them pass through a heat-using unit. The first heat exchange tube group and the second heat exchange tube group are opened and closed asynchronously. Antifreeze flows in the first heat exchange tube group, and softened water flows in the second heat exchange tube group. A scraper blade is slidably installed on the inner wall of the heat exchanger box. The scraper blade has two rows of openings, which are respectively fitted onto the first heat exchanger tube group and the second heat exchanger tube group. The two rows of openings are slidably connected to the outer circular surface of the tube bundles of the first heat exchanger tube group and the second heat exchanger tube group. The first heat exchanger tube group and the second heat exchanger tube group are both located directly above the drain outlet. The scraper blade is driven to move up and down by a drive assembly.

[0006] As a further embodiment of the present invention: the drive assembly includes a turbine, a transmission assembly, a fixed block, and a reciprocating screw. The turbine is rotatably installed inside the intake pipe, the fixed block is fixedly installed on the inner wall of the heat exchange box, and the reciprocating screw is rotatably installed on the fixed block. The reciprocating screw is vertically arranged and threadedly connected to the scraper blade. The turbine is connected to the reciprocating screw through the transmission assembly. When exhaust steam enters the heat exchange box from the intake pipe, it drives the turbine to rotate, and the turbine drives the reciprocating screw to rotate through the transmission assembly.

[0007] As a further embodiment of the present invention: the transmission assembly includes a support frame, a transmission wheel, a locking assembly, a first rotating wheel, a second rotating wheel, a first synchronous belt, and a second synchronous belt. The support frame is fixedly installed on the inner wall of the heat exchange box and is located above the fixed block. The transmission wheel is rotatably installed inside the support frame. The transmission wheel is coaxially arranged with the reciprocating screw. The transmission wheel is temporarily rigidly connected to the reciprocating screw through the locking assembly. The first rotating wheel is coaxially fixedly connected to the turbine. The second rotating wheel is rotatably installed on the top plate of the heat exchange box. The first rotating wheel is driven by the second rotating wheel through the first synchronous belt, and the second rotating wheel is driven by the transmission wheel through the second synchronous belt.

[0008] As a further aspect of the present invention: the locking assembly includes a square groove, a square block, a first magnet, a second magnet, and an electric cylinder. The transmission wheel has a square groove, the square block is slidably installed in the square groove, the electric cylinder is fixedly installed on the top of the heat exchange box, and the movable end of the electric cylinder is rotatably connected to the top of the square block. The first magnet is coaxially fixedly installed on the bottom of the square block, and the second magnet is coaxially fixedly installed on the top of the reciprocating screw. When the electric cylinder drives the square block to descend, the first magnet and the second magnet are in contact; when the electric cylinder drives the square block to rise, the first magnet and the second magnet are separated.

[0009] As a further aspect of the present invention: an electric butterfly valve is provided on the exhaust pipe, and the electric butterfly valve adjusts the exhaust steam flow rate in the exhaust pipe. In winter, the electric butterfly valve reduces the exhaust steam flow rate in the exhaust pipe, and in summer, the electric butterfly valve increases the exhaust steam flow rate in the exhaust pipe.

[0010] As a further aspect of the present invention: the tube bundle gap of the first heat exchange tube group is greater than the tube bundle gap of the second heat exchange tube group, and the bending radius of the first heat exchange tube group is greater than the bending radius of the second heat exchange tube group.

[0011] As a further aspect of the present invention: the first heat exchange tube group is located between the air inlet pipe and the second heat exchange tube group, and the tube bundles of the first heat exchange tube group and the tube bundles of the second heat exchange tube group are arranged in a staggered manner.

[0012] As a further aspect of the present invention: the bend of the first heat exchange tube group is provided with a first drainage groove, the bend of the second heat exchange tube group is provided with a second drainage groove, and the surfaces of the first heat exchange tube group and the second heat exchange tube group are both coated with a hydrophobic coating.

[0013] The beneficial effects of this invention are: 1. In this invention, by setting up a first heat exchange tube group and a second heat exchange tube group and adopting an asynchronous opening and closing design, the first heat exchange tube group circulates antifreeze to meet the winter antifreeze requirements, and the second heat exchange tube group circulates softened water to meet the high-efficiency heat exchange requirements in summer. At the same time, combined with the electric butterfly valve to adjust the waste steam flow in the outlet pipe differently in winter and summer, it not only solves the problem that a single heat exchange medium cannot meet both winter and summer operating conditions and that the pipeline is prone to freezing in winter, but also avoids the reduction in unit power generation efficiency caused by artificial pressure buildup in summer, thus achieving adaptive matching of winter and summer operating conditions and taking into account both waste heat recovery efficiency and equipment operation safety. 2. In this invention, the turbine is driven to rotate by the kinetic energy of the exhaust steam. Through the cooperation of the transmission component and the locking component, the scraper blade can be automatically raised and lowered as needed. The openings on the scraper blade fit against the outer wall of the heat exchange tube bundle to scrape off the condensate film. At the same time, combined with the hydrophobic coating on the surface of the heat exchange tube bundle and the design of the condensate groove on the bend head, the condensate discharge is further optimized. This effectively solves the problems of the condensate film increasing the heat exchange thermal resistance and the tube bundle being easily damaged by ice in winter. No additional power source is required, the structure is simplified and the operating cost is reduced. 3. In this invention, the first heat exchange tube group and the second heat exchange tube group adopt a differentiated structural design. The first heat exchange tube group adopts a larger bending radius and tube bundle gap to adapt to the flow characteristics of antifreeze, while the second heat exchange tube group adopts a smaller bending radius and a denser arrangement to increase the heat exchange area. In addition, the two sets of tube bundles are staggered to avoid mutual obstruction. This not only solves the problem of high antifreeze flow resistance and easy freezing in winter, but also improves the waste heat recovery efficiency in summer. At the same time, it facilitates the smooth operation of the wiper blade and extends the service life of the components. Attached Figure Description

[0014] The invention will now be further described with reference to the accompanying drawings.

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the heat exchange box in this invention; Figure 3 This is a cross-sectional structural schematic diagram of the heat exchange box in this invention; Figure 4 This is a schematic diagram of the internal structure of the heat exchange box in this invention; Figure 5 This is a schematic diagram of the structure of the wiper blade in this invention; Figure 6 This is a schematic diagram of the structure of the first heat exchange tube and the second heat exchange tube in this invention; Figure 7 This is a schematic diagram of the transmission wheel in this invention; Figure 8 This is a schematic diagram of the square block structure in this invention; Figure 9 This is a schematic diagram of the structure in which the first magnet and the second magnet are bonded together in this invention; Figure 10 This is a schematic diagram of the side structure of the heat exchange box in this invention.

[0016] In the diagram: 1. Heat exchanger housing; 101. Drain outlet; 102. Fixing block; 103. Support frame; 2. Inlet pipe; 201. Turbine; 3. Outlet pipe; 301. Electric butterfly valve; 4. First heat exchanger tube assembly; 401. First drainage groove; 5. Second heat exchanger tube assembly; 501. Second drainage groove; 6. Drain pipe; 601. Solenoid valve; 7. Scraper; 701. Opening; 8. Reciprocating screw; 9. First impeller; 10. Second impeller; 11. First synchronous belt; 12. Second synchronous belt; 13. Transmission wheel; 1301. Square groove; 14. Square block; 15. First magnet; 16. Second magnet; 17. Electric cylinder. Detailed Implementation

[0017] 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.

[0018] Please see Figures 1-10 As shown, the present invention is a frost-resistant waste heat recovery device for an air-cooled island, comprising: A heat exchange box 1 has an air inlet pipe 2 connected to its top, which is connected to the exhaust pipe of a steam turbine. An air outlet pipe 3 is connected to one side of the heat exchange box 1, which is connected to the steam inlet pipe of an air-cooled island. A drain outlet 101 is provided at the bottom of the heat exchange box 1, which is connected to a drain pipe 6. A solenoid valve 601 is installed on the drain pipe 6. A first heat exchange tube group 4 and a second heat exchange tube group 5 are arranged inside the heat exchange box 1. The first heat exchange tube group 4 and the second heat exchange tube group 5 are arranged side by side and are respectively connected to two external circulation components. Both of them pass through a heat-using unit. The first heat exchange tube group 4 and the second heat exchange tube group 5 are opened and closed asynchronously. Antifreeze flows in the first heat exchange tube group 4, and softened water flows in the second heat exchange tube group 5. The scraper blade 7 is slidably installed on the inner wall of the heat exchange box 1. The scraper blade 7 has two rows of openings 701, which are respectively sleeved on the first heat exchange tube group 4 and the second heat exchange tube group 5, and are slidably connected to the outer circular surface of the tube bundles of the first heat exchange tube group 4 and the second heat exchange tube group 5. The first heat exchange tube group 4 and the second heat exchange tube group 5 are both located directly above the drain outlet 101. The scraper blade 7 is driven to move up and down by a drive assembly.

[0019] The two circulation components are connected to the first heat exchange tube group 4 and the second heat exchange tube group 5 respectively, and are used to circulate antifreeze and softened water. The heated circulating medium is transported to the heat-using unit, such as heating or production heat, for heat utilization. After cooling, it is returned to realize the recovery and utilization of waste heat from exhaust steam, solving the problem of energy waste caused by the direct discharge of waste heat from exhaust steam in the background technology.

[0020] The working principle of this invention is as follows: A heat exchanger box 1 is installed between the steam turbine and the air-cooled island. The first heat exchanger tube group 4 and the second heat exchanger tube group 5 are arranged in parallel within the heat exchanger box 1, employing an asynchronous opening and closing design. In summer, the first heat exchanger tube group 4 is closed and the second heat exchanger tube group 5 is opened, utilizing softened water for heat exchange, adapting to high-temperature summer conditions without requiring additional pressure control. In winter, the second heat exchanger tube group 5 is closed and the first heat exchanger tube group 4 is opened, utilizing antifreeze for heat exchange, solving the problem of pipe freezing in winter. The specific heat exchange process is as follows: The exhaust steam discharged from the turbine enters the heat exchange box 1 through the inlet pipe 2. The exhaust steam diffuses in the heat exchange box 1 and comes into full contact with the outer wall of the tube bundle of the first heat exchange tube group 4 or the second heat exchange tube group 5 to exchange heat. At this time, the exhaust steam has just been discharged from the turbine and carries a large amount of low-grade waste heat, which can be effectively absorbed by the antifreeze or softened water in the tubes to achieve waste heat recovery and avoid the problem of energy waste. During the heat exchange process, since the temperature of the exhaust steam is higher than that of the medium inside the tubes, the exhaust steam will condense on the outer wall of the tube bundle of the first heat exchange tube group 4 or the second heat exchange tube group 5, forming condensate droplets. If not removed in time, a thick water film will form, increasing the heat exchange thermal resistance, reducing the waste heat recovery efficiency, and in winter, it is also easy to freeze and damage the tube bundle. Therefore, the drive assembly drives the scraper 7 to rise and fall along the inner wall of the heat exchange box 1. The opening 701 on the scraper 7 slides along the outer circular surface of the tube bundle of the first heat exchange tube group 4 or the second heat exchange tube group 5 to scrape off the condensate on the outer wall of the tube bundle. The scraped condensate slides down the outer wall of the tube bundle and falls to the drain outlet 101 at the bottom of the heat exchange box 1, where it collects in the drain pipe 6. During the heat exchange process of transporting exhaust steam, the solenoid valve 601 remains closed to prevent exhaust steam from leaking from the drain pipe 6. When too much condensate accumulates in the drain pipe 6, the solenoid valve 601 is opened to drain the condensate, preventing the condensate from accumulating and submerging the tube bundle, and further avoiding the problem of condensate freezing and clogging the flow channel in winter. After heat exchange through the first heat exchange tube group 4 or the second heat exchange tube group 5 in the heat exchange box 1, the temperature of the exhaust steam decreases and the waste heat is recovered. At this time, the exhaust steam is discharged through the exhaust pipe 3 and enters the heat dissipation fins of the air-cooled island for subsequent condensation. Since the exhaust steam has been cooled in advance, the condensation efficiency of the air-cooled island can be improved. Especially in summer, there is no need to increase the speed of the air-cooled fan. The exhaust steam can be quickly condensed by natural wind speed or conventional wind speed, which reduces the energy consumption of the unit and solves the problems of insufficient condensation efficiency and high energy consumption of the air-cooled island.

[0021] like Figures 1-9 As shown in the preferred embodiment of the present invention, the drive assembly includes a turbine 201, a transmission assembly, a fixed block 102, and a reciprocating screw 8. The turbine 201 is rotatably mounted inside the intake pipe 2. The fixed block 102 is fixedly mounted on the inner wall of the heat exchange box 1. The reciprocating screw 8 is rotatably mounted on the fixed block 102. The reciprocating screw 8 is vertically arranged and threadedly connected to the scraper 7. The turbine 201 is connected to the reciprocating screw 8 through the transmission assembly. When exhaust steam enters the heat exchange box 1 from the intake pipe 2, it drives the turbine 201 to rotate. The turbine 201 drives the reciprocating screw 8 to rotate through the transmission assembly.

[0022] In practical application, when the exhaust steam enters the heat exchange box 1 from the inlet pipe 2, the kinetic energy of the exhaust steam drives the turbine 201 to rotate around its own axis without the need for an additional motor. After the turbine 201 rotates, the rotational power is transmitted to the reciprocating screw 8 through the transmission assembly, causing the reciprocating screw 8 to rotate around its own axis. Since the reciprocating screw 8 is threadedly connected to the scraper 7 and the scraper 7 is slidably installed on the inner wall of the heat exchange box 1, the rotational motion of the reciprocating screw 8 is precisely converted into the vertical lifting motion of the scraper 7, realizing the automatic lifting and scraping of water by the scraper 7. In this way, the exhaust steam itself is driven by residual pressure, synchronized with the system operation, and can promptly follow the exhaust steam condensation rhythm to scrape off the water film, avoiding the accumulation of water film and increasing thermal resistance. At the same time, no additional power source is required, simplifying the structure, reducing operating costs, and avoiding the problems of difficult removal of condensate film and low heat exchange efficiency.

[0023] like Figures 1-9 As shown, in a preferred embodiment of the present invention, the transmission assembly includes a support frame 103, a transmission wheel 13, a locking assembly, a first rotating wheel 9, a second rotating wheel 10, a first synchronous belt 11, and a second synchronous belt 12. The support frame 103 is fixedly installed on the inner wall of the heat exchange box 1 and is located above the fixing block 102. The transmission wheel 13 is rotatably installed inside the support frame 103. The transmission wheel 13 is coaxially arranged with the reciprocating screw 8. The transmission wheel 13 is temporarily rigidly connected to the reciprocating screw 8 through the locking assembly. The first rotating wheel 9 is coaxially fixedly connected to the turbine 201. The second rotating wheel 10 is rotatably installed on the top plate of the heat exchange box 1. The first rotating wheel 9 is drivenly connected to the second rotating wheel 10 through the first synchronous belt 11, and the second rotating wheel 10 is drivenly connected to the transmission wheel 13 through the second synchronous belt 12.

[0024] Specifically, the locking assembly includes a square groove 1301, a square block 14, a first magnet 15, a second magnet 16, and an electric cylinder 17. The transmission wheel 13 has a square groove 1301, and the square block 14 is slidably installed in the square groove 1301. The electric cylinder 17 is fixedly installed on the top of the heat exchange box 1, and the movable end of the electric cylinder 17 is rotatably connected to the top of the square block 14. The first magnet 15 is coaxially fixedly installed on the bottom of the square block 14, and the second magnet 16 is coaxially fixedly installed on the top of the reciprocating screw 8. When the electric cylinder 17 drives the square block 14 to descend, the first magnet 15 and the second magnet 16 are in contact. When the electric cylinder 17 drives the square block 14 to rise, the first magnet 15 and the second magnet 16 are separated.

[0025] In practical application of this embodiment, during the normal heat exchange phase, condensate droplets gradually accumulate on the tube walls of the first heat exchanger tube group 4 or the second heat exchanger tube group 5. At this time, there is no need for scraping. The electric cylinder 17 is activated, driving the square block 14 to rise vertically along the square groove 1301. The square block 14 drives the first magnet 15 at the bottom to rise synchronously, separating the first magnet 15 from the second magnet 16 at the top of the reciprocating screw 8, cutting off the power transmission between the transmission wheel 13 and the reciprocating screw 8. Meanwhile, the exhaust steam continues to drive the turbine 201 to rotate through the intake pipe 2. The turbine 201 drives... The first rotating wheel 9, which is fixed on the same axis, rotates synchronously. The first rotating wheel 9 drives the second rotating wheel 10 to rotate through the first synchronous belt 11. The second rotating wheel 10 drives the transmission wheel 13 to rotate on the support frame 103 through the second synchronous belt 12. Since the square block 14 is slidably installed in the square groove 1301, the transmission wheel 13 drives the square block 14 to rotate synchronously when it rotates. The square block 14 rotates at the movable end of the electric cylinder 17, so that the transmission wheel 13 can rotate freely and will not drive the reciprocating screw 8 to rotate. The wiper blade 7 remains stationary, avoiding tube bundle wear and energy waste caused by ineffective wiping. When a large amount of condensate accumulates on the tube wall of the first heat exchanger tube group 4 or the second heat exchanger tube group 5, forming a water film that affects heat exchange efficiency, or when there is a risk of freezing in winter, the electric cylinder 17 is activated, driving the square block 14 to descend vertically along the square groove 1301. The square block 14 drives the first magnet 15 to descend synchronously, so that the first magnet 15 and the second magnet 16 are in contact. Through magnetic attraction, a temporary rigid connection is achieved between the square block 14 and the reciprocating screw 8. At this time, when the transmission wheel 13 rotates, it drives the square block 14 to rotate synchronously through the cooperation of the square groove 1301 and the square block 14. The square block 14 drives the reciprocating screw 8 to rotate synchronously through the rigid connection between the first magnet 15 and the second magnet 16. The reciprocating screw 8 drives the scraper 7 to rise and fall vertically, completing the scraping action and scraping off the condensate film on the tube wall, thus solving the problems of increased thermal resistance and easy freezing in winter caused by the condensate film in the background technology. After wiping is completed, the electric cylinder 17 drives the square block 14 to rise again, cutting off the power transmission, and the wiper blade 7 returns to a stationary position, realizing on-demand control of the wiping action, taking into account both heat exchange efficiency and component lifespan.

[0026] like Figures 1-4 As shown, in a preferred embodiment of the present invention, an electric butterfly valve 301 is provided on the exhaust pipe 3. The electric butterfly valve 301 adjusts the exhaust steam flow rate in the exhaust pipe 3. In winter, the electric butterfly valve 301 reduces the exhaust steam flow rate in the exhaust pipe 3, and in summer, the electric butterfly valve 301 increases the exhaust steam flow rate in the exhaust pipe 3.

[0027] In practical application, under winter conditions, the air-cooled tube bundle is prone to freezing and cracking due to excessive cooling in low-temperature environments. Therefore, it is necessary to increase the condensation temperature of the exhaust steam. Thus, the electric butterfly valve 301 is activated, and its opening is adjusted to reduce the exhaust steam flow rate in the outlet pipe 3. Since the exhaust steam flow rate delivered by the inlet pipe 2 is constant, the reduced exhaust steam discharge from the outlet pipe 3 leads to exhaust steam accumulation in the heat exchange chamber 1, increasing the exhaust steam saturation and consequently raising the saturation temperature of the exhaust steam, resulting in high back pressure. Under high back pressure, when the exhaust steam exchanges heat with the antifreeze flowing in the first heat exchange tube group 4, the antifreeze temperature rises, meeting the high heat demand of the heating unit in winter. Simultaneously, it increases the overall temperature within the heat exchange chamber 1, preventing ice formation on the first heat exchange tube group 4 and the inner wall of the heat exchange chamber 1, thus avoiding the problems of easy freezing of the air-cooled tube bundle and insufficient waste heat recovery temperature in winter. Summer operating conditions: In summer, the ambient temperature is high, the cooling effect of the air-cooled island is weakened, the condensation rate of the turbine exhaust steam decreases, and the exhaust back pressure is naturally maintained at a high level. There is no need to artificially suppress the pressure. Therefore, the electric butterfly valve 301 is activated and its opening is adjusted to the maximum to increase the exhaust steam flow in the outlet pipe 3, ensuring smooth flow of exhaust steam in the heat exchange box 1, avoiding the accumulation of exhaust steam that leads to excessive back pressure, and thus avoiding the problem of increasing the turbine exhaust resistance and reducing the unit's power generation efficiency. At the same time, it adapts to the softened water heat exchange requirements of the second heat exchange tube group 5 in summer, and achieves efficient waste heat recovery.

[0028] like Figures 1-6 As shown, in a preferred embodiment of the present invention, the tube bundle gap of the first heat exchange tube group 4 is greater than the tube bundle gap of the second heat exchange tube group 5, and the bending radius of the first heat exchange tube group 4 is greater than the bending radius of the second heat exchange tube group 5.

[0029] Specifically, the first heat exchange tube group 4 is located between the air inlet pipe 2 and the second heat exchange tube group 5, and the tube bundles of the first heat exchange tube group 4 and the tube bundles of the second heat exchange tube group 5 are arranged in a staggered manner.

[0030] In practical applications, because the viscosity of antifreeze is greater than that of softened water, its flow resistance is higher. If the bending radius is too small, it can easily lead to poor antifreeze flow and pipe blockage. Uneven flow velocity can also cause local low temperatures, which can lead to pipe freezing. Therefore, the bending radius of the first heat exchange tube group 4 is designed to be larger and gentler to reduce the flow resistance of the antifreeze, ensure smooth flow of the antifreeze in the tubes, and avoid local low temperature freezing. At the same time, the tube bundle gap of the first heat exchange tube group 4 is designed to be larger, which can reduce the accumulation of condensate in the tube bundle gap in winter and further reduce the risk of freezing. Softened water has good fluidity and low flow resistance. Therefore, the bending radius of the second heat exchange tube group 5 is designed to be smaller and denser, which allows more tube bundles to be laid in the limited space of the heat exchange box 1, increasing the heat exchange area and improving the efficiency of waste heat recovery in summer. At the same time, the tube bundle gap of the second heat exchange tube group 5 is designed to be smaller, eliminating the need to consider the freezing problem, focusing on increasing the heat exchange area and maximizing the recovery of waste heat from exhaust steam. Furthermore, the first heat exchange tube group 4 is located between the inlet pipe 2 and the second heat exchange tube group 5, which allows the exhaust steam to come into contact with the first heat exchange tube group 4 first after entering the heat exchange box 1, achieving more sufficient heat exchange in winter conditions, improving the heating efficiency of the antifreeze, and meeting the heating demand in winter. The staggered arrangement of the first heat exchange tube group 4 and the second heat exchange tube group 5 can minimize the obstruction of the second heat exchange tube group 5 by the first heat exchange tube group 4, ensuring that the exhaust steam can smoothly contact the second heat exchange tube group 5 in summer conditions, ensuring the heat exchange efficiency in summer, while avoiding mutual interference between the two tube bundles, ensuring stability when switching between winter and summer conditions.

[0031] like Figures 1-6 As shown, in a preferred embodiment of the present invention, the bend of the first heat exchange tube group 4 is provided with a first drainage groove 401, the bend of the second heat exchange tube group 5 is provided with a second drainage groove 501, and the surfaces of the first heat exchange tube group 4 and the second heat exchange tube group 5 are both coated with a hydrophobic coating.

[0032] In practical applications, the hydrophobic coating sprayed on the surfaces of the first heat exchange tube group 4 and the second heat exchange tube group 5 can reduce the adhesion between condensate droplets and the outer wall of the tube bundle, prevent condensate droplets from staying and accumulating on the outer wall of the tube bundle, and allow condensate droplets to slide off quickly, reducing the formation of water film. The bends of the first heat exchanger tube group 4 and the second heat exchanger tube group 5 are where condensate droplets are most likely to accumulate. The first drain groove 401 and the second drain groove 501 are provided to guide the condensate droplets at the bends to slide down along the drain grooves, preventing the droplets from accumulating at the bends to form a water film or ice, further optimizing the scraping effect, and ensuring that the condensate can be smoothly collected at the drain outlet 101 and discharged through the drain pipe 6.

[0033] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A freeze-resistant waste heat recovery device for an air-cooled island, characterized in that, include: A heat exchange box (1) is connected to an air inlet pipe (2) at the top of the heat exchange box (1), which is connected to the exhaust pipe of the steam turbine. An air outlet pipe (3) is connected to one side of the heat exchange box (1), which is connected to the steam inlet pipe of the air-cooled island. A drain outlet (101) is provided at the bottom of the heat exchange box (1), which is connected to a drain pipe (6). A solenoid valve (601) is provided on the drain pipe (6). A first heat exchange tube group (4) and a second heat exchange tube group (5) are arranged inside the heat exchange box (1). The first heat exchange tube group (4) and the second heat exchange tube group (5) are arranged side by side and are connected to two external circulation components respectively. Both of them pass through a heat-using unit. The first heat exchange tube group (4) and the second heat exchange tube group (5) are opened and closed asynchronously. Antifreeze flows in the first heat exchange tube group (4), and softened water flows in the second heat exchange tube group (5). The scraper (7) is slidably installed on the inner wall of the heat exchange box (1). The scraper (7) has two rows of openings (701). The two rows of openings (701) are respectively sleeved on the first heat exchange tube group (4) and the second heat exchange tube group (5). The two rows of openings (701) are slidably connected to the outer circular surface of the tube bundle of the first heat exchange tube group (4) and the second heat exchange tube group (5). The first heat exchange tube group (4) and the second heat exchange tube group (5) are both located directly above the drain outlet (101). The scraper (7) is driven to rise and fall by the drive assembly.

2. The antifreeze type air-cooled island waste heat recovery device according to claim 1, characterized in that, The drive assembly includes a turbine (201), a transmission assembly, a fixed block (102), and a reciprocating screw (8). The turbine (201) is rotatably installed inside the air inlet pipe (2). The fixed block (102) is fixedly installed on the inner wall of the heat exchange box (1). The reciprocating screw (8) is rotatably installed on the fixed block (102). The reciprocating screw (8) is vertically arranged. The reciprocating screw (8) is threadedly connected to the scraper (7). The turbine (201) is connected to the reciprocating screw (8) through the transmission assembly. When exhaust steam enters the heat exchange box (1) from the air inlet pipe (2), it drives the turbine (201) to rotate. The turbine (201) drives the reciprocating screw (8) to rotate through the transmission assembly.

3. The antifreeze type air-cooled island waste heat recovery device according to claim 2, characterized in that, The transmission assembly includes a support frame (103), a transmission wheel (13), a locking assembly, a first rotating wheel (9), a second rotating wheel (10), a first synchronous belt (11), and a second synchronous belt (12). The support frame (103) is fixedly installed on the inner wall of the heat exchange box (1) and is located above the fixed block (102). The transmission wheel (13) is rotatably installed inside the support frame (103). The transmission wheel (13) is coaxially arranged with the reciprocating screw (8). The transmission wheel (13) is temporarily rigidly connected to the reciprocating screw (8) through the locking assembly. The first rotating wheel (9) is coaxially fixedly connected to the turbine (201). The second rotating wheel (10) is rotatably installed on the top plate of the heat exchange box (1). The first rotating wheel (9) is connected to the second rotating wheel (10) through the first synchronous belt (11). The second rotating wheel (10) is connected to the transmission wheel (13) through the second synchronous belt (12).

4. The antifreeze type air-cooled island waste heat recovery device according to claim 3, characterized in that, The locking assembly includes a square groove (1301), a square block (14), a first magnet (15), a second magnet (16), and an electric cylinder (17). The transmission wheel (13) has a square groove (1301) inside. The square block (14) is slidably installed in the square groove (1301). The electric cylinder (17) is fixedly installed on the top of the heat exchange box (1). The movable end of the electric cylinder (17) is rotatably connected to the top of the square block (14). The first magnet (15) is coaxially fixedly installed on the bottom of the square block (14). The second magnet (16) is coaxially fixedly installed on the top of the reciprocating screw (8). When the electric cylinder (17) drives the square block (14) to descend, the first magnet (15) and the second magnet (16) are in contact. When the electric cylinder (17) drives the square block (14) to rise, the first magnet (15) and the second magnet (16) are separated.

5. The antifreeze type air-cooled island waste heat recovery device according to claim 1, characterized in that, An electric butterfly valve (301) is provided on the exhaust pipe (3). The electric butterfly valve (301) adjusts the exhaust steam flow rate in the exhaust pipe (3). In winter, the electric butterfly valve (301) reduces the exhaust steam flow rate in the exhaust pipe (3). In summer, the electric butterfly valve (301) increases the exhaust steam flow rate in the exhaust pipe (3).

6. The antifreeze type air-cooled island waste heat recovery device according to claim 1, characterized in that, The tube bundle gap of the first heat exchange tube group (4) is greater than the tube bundle gap of the second heat exchange tube group (5), and the bending radius of the first heat exchange tube group (4) is greater than the bending radius of the second heat exchange tube group (5).

7. A frost-resistant air-cooled island waste heat recovery device according to claim 6, characterized in that, The first heat exchange tube group (4) is located between the air inlet pipe (2) and the second heat exchange tube group (5), and the tube bundles of the first heat exchange tube group (4) and the tube bundles of the second heat exchange tube group (5) are arranged in a staggered manner.

8. The antifreeze type air-cooled island waste heat recovery device according to claim 1, characterized in that, The first heat exchange tube group (4) has a first drainage groove (401) at the bend head, and the second heat exchange tube group (5) has a second drainage groove (501) at the bend head. The surfaces of the first heat exchange tube group (4) and the second heat exchange tube group (5) are both coated with a hydrophobic coating.

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