A surface type desuperheater and method of use thereof

Abstract

The application discloses a surface type desuperheater and a use method thereof, and belongs to the technical field of desuperheaters. The application is characterized in that a flow guide baffle fixed at both ends of a support member is arranged in a heat exchange space, and the flow guide baffle is provided with an opening facing an air inlet and a flow discharge hole away from the air inlet. The flow path of the shell side fluid is changed, the wall attachment flow and the short circuit phenomenon are reduced, the residual fluid which fails to participate in effective heat exchange is discharged through the flow discharge hole, the combination of the two makes the fluid distribution more uniform, the heat exchange area of the heat exchange tube bundle is fully utilized, and thus the heat exchange efficiency of the surface type desuperheater is improved. An axial sliding connection structure is arranged between the support member and the cylinder body, the support member is allowed to slide along the cylinder body in the axial direction, when the heat exchange tube bundle and the cylinder body are inconsistent in axial thermal expansion due to temperature difference, the support member can release displacement through sliding, and thus the great thermal stress caused by forced constraint in the traditional fixed support structure is avoided, and thus the reliability and service life of equipment operation are improved.

Description

Technical Field

[0001] This invention relates to the field of desuperheater technology, specifically to a surface desuperheater and its usage method. Background Technology

[0002] As one of the core components of a supercritical carbon dioxide power generation system, the operational stability and temperature regulation performance of a supercritical carbon dioxide boiler directly determine the safety, reliability, and power generation efficiency of the entire system. During boiler operation, to control the temperature of the superheated working fluid within the design limits and prevent damage to the heating surface metal due to excessive heat, or impact on turbine efficiency and safety due to excessively low temperatures, reliable temperature regulation methods must be employed. The circulating working fluid in a supercritical carbon dioxide boiler is carbon dioxide, whose critical point temperature is only 31.1℃, far below the design temperature of the boiler superheater outlet. Therefore, the latent heat of vaporization cannot be utilized for cooling, making traditional water spray desuperheating methods completely unsuitable for supercritical carbon dioxide boilers.

[0003] To address the temperature control challenges of supercritical carbon dioxide boilers, the industry has attempted to employ jet desuperheating, which involves directly injecting low-temperature carbon dioxide into the high-temperature carbon dioxide main gas stream. However, this method has significant drawbacks: to achieve the desired cooling effect, a large amount of low-temperature carbon dioxide needs to be injected, which significantly reduces the flow rate of the working fluid through the boiler's air-cooled walls, weakening the cooling capacity of the air-cooled walls and easily leading to overheating and tube rupture, seriously threatening the safe operation of the boiler.

[0004] As an indirect heat exchange temperature control device, the surface desuperheater exchanges heat between the temperature-regulating medium and the regulated medium through the heat exchange tube wall, with the media on both sides not in contact. This fundamentally avoids the problem of reduced flow rate on the air-cooled wall caused by jet desuperheating, making it a major research direction and application choice for temperature control technology in supercritical carbon dioxide boilers. However, existing surface desuperheaters have revealed a critical problem of low heat exchange efficiency when practically applied to supercritical carbon dioxide boilers. The main reason for this lies in the obvious defects in the shell-side fluid distribution structure design of existing surface desuperheaters: when the high-temperature, high-pressure carbon dioxide working fluid enters the shell side from the inlet, due to the lack of effective flow guidance and distribution measures, the fluid is prone to severe wall-attached flow or short-circuiting. Most of the working fluid flows rapidly along the inner wall of the shell, failing to uniformly and fully flush the entire surface of the heat exchange tube bundle. This results in the effective heat exchange area of ​​the heat exchange tube bundle not being fully utilized, leading to a low overall heat transfer coefficient. To achieve the same temperature control effect, the heat exchange area needs to be significantly increased, making the desuperheater bulky and costly to manufacture, which is difficult to meet the compact development requirements of supercritical carbon dioxide power generation systems.

[0005] Therefore, how to improve the heat exchange efficiency of surface desuperheaters has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a surface desuperheater and its usage method to overcome the problem of low heat exchange efficiency in existing surface desuperheaters.

[0007] The present invention solves the above-mentioned technical problems through the following technical solution: This invention provides a surface desuperheater, comprising a cylinder, heat exchange tubes, a support member, and a flow guide baffle. The cylinder has an air inlet and an air outlet. The support member is disposed inside the cylinder, forming a heat exchange space, and the heat exchange tubes are arranged within the heat exchange space. The flow guide baffle is disposed within the heat exchange space, with both ends fixed to the support member. The flow guide baffle has an opening facing the air inlet and a vent hole away from the air inlet. An axial sliding connection structure is provided between the support member and the cylinder to allow the support member to slide axially along the cylinder.

[0008] A further improvement of the present invention is that the flow guide baffle is a U-shaped baffle, with both ends of the U-shaped baffle fixed to the support member, and the opening of the U-shaped baffle facing the air inlet.

[0009] A further improvement of the present invention is that the vent hole is located at the bottom of the U-shaped baffle away from the air inlet.

[0010] A further improvement of the present invention is that the axial sliding connection structure includes a slider and a groove that cooperate with each other, the slider is fixed to the support member, and the groove is provided on the inner wall of the cylinder.

[0011] A further improvement of the present invention is that the heat exchange tube is a finned tube.

[0012] A further improvement of the present invention is that the finned tube has a serpentine structure and is arranged with circular fins.

[0013] A further improvement of the present invention is that the cylinder is provided with multiple air inlets and air outlets, and the air inlets and air outlets are distributed along the axial direction of the cylinder.

[0014] A further improvement of the present invention is that the surface desuperheater also includes an inlet pipe and an outlet pipe, with one end of the heat exchange tube connected to the inlet pipe and the other end connected to the outlet pipe.

[0015] A further improvement of the present invention is that the flow area of ​​the drain hole is smaller than the flow area of ​​the opening.

[0016] The present invention also provides a method of using the surface desuperheater as described above, comprising the following steps: introducing the fluid to be desuperheated into the heat exchange space through the air inlet; guiding the fluid to be desuperheated to flush the heat exchange tube through the opening of the guide baffle, and discharging the residual fluid through the drain hole; discharging the fluid to be desuperheated through the air outlet after exchanging heat with the cooling medium in the heat exchange tube; and sliding the support member along the axial direction of the cylinder through the axial sliding connection structure to adapt to the thermal expansion difference.

[0017] Compared with the prior art, the positive and progressive effects of the present invention are as follows: The surface desuperheater provided by this invention alters the flow path of the shell-side fluid by incorporating flow guide baffles fixed at both ends to the support within the heat exchange space. These baffles have openings facing the air inlet and vent holes away from the air inlet. The openings force the incoming fluid to face-brush the heat exchange tube bundle, significantly reducing wall-attached flow and short-circuiting phenomena. The vent holes discharge residual fluid that fails to participate in effective heat exchange, eliminating dead zones. This combination results in more uniform fluid distribution and full utilization of the heat exchange area of ​​the heat exchange tube bundle, thereby improving the heat exchange efficiency of the surface desuperheater and helping to reduce the size of the equipment. An axial sliding connection structure is provided between the support and the shell, allowing the support to slide axially along the shell. When the axial thermal expansion of the heat exchange tube bundle and the shell is inconsistent due to temperature differences, the support can release its displacement through sliding, avoiding the huge thermal stress caused by forced constraints in traditional fixed support structures, thus improving the reliability and service life of the equipment. Attached Figure Description

[0018] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 This is a cross-sectional view of the surface desuperheater of the present invention; Figure 2 This is a side view of the surface desuperheater of the present invention.

[0020] The components are as follows: 1. Front cover; 2. Flange; 3. Flange cover; 4. Sleeve; 5. Water outlet pipe; 6. Water inlet pipe; 7. Cylinder; 8. Sealing baffle; 9. U-shaped baffle; 10. Heat exchange tube; 11. Air outlet; 12. Rear cover; 13. Hand hole device; 14. Air inlet; 15. Sliding block. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This is an explanation of the present invention and not a limitation thereof.

[0027] This invention provides a surface desuperheater, comprising a cylinder 7, a heat exchange tube 10, a support member, and a flow guide baffle. The cylinder 7 is provided with an air inlet 14 and an air outlet 11. The support member is disposed inside the cylinder 7, forming a heat exchange space, and the heat exchange tube 10 is arranged in the heat exchange space. The flow guide baffle is disposed in the heat exchange space, with both ends fixed to the support member. The flow guide baffle has an opening facing the air inlet 14 and a vent hole away from the air inlet 14. An axial sliding connection structure is provided between the support member and the cylinder 7 for allowing the support member to slide axially along the cylinder 7.

[0028] By setting up guide baffles with openings facing the air inlet 14 and vent holes away from the air inlet 14, the fluid entering the heat exchange space is forced to flush the heat exchange tube bundle 10, avoiding short circuits against the wall, and the residual fluid is discharged through the vent holes to eliminate dead zones; at the same time, the axial sliding connection structure allows the support to slide, effectively releasing the axial thermal expansion difference between the tube bundle and the cylinder 7, thereby achieving the purpose of improving heat exchange efficiency and eliminating axial thermal stress.

[0029] Specifically, the baffle is a U-shaped baffle 9, with both ends of the U-shaped baffle 9 fixed to the support, and the opening of the U-shaped baffle 9 facing the air inlet 14.

[0030] The specific shape and orientation of the U-shaped baffle 9 further optimizes the flow guidance effect of the fluid and enhances the uniformity of the shell-side fluid scouring the tube bundle. The two side walls and the bottom wall of the U-shaped baffle 9 together enclose a semi-closed flow-facing chamber. When the fluid to be cooled rushes in from the air inlet 14, this semi-closed U-shaped opening structure is like a funnel that catches the wind, which can more concentratedly capture and gather the high-speed fluid, forcing the fluid to generate a pressurization effect in the chamber. As a result, the fluid sweeps across the surface of the heat exchange tube 10 laterally with a stronger scouring pressure, which greatly enhances the forced convection heat transfer effect between the fluid and the tube bundle.

[0031] Specifically, the vent hole is located at the bottom of the U-shaped baffle 9 away from the air inlet 14.

[0032] The specific shape and orientation of the U-shaped baffle 9 further optimizes the flow guidance effect of the fluid and enhances the uniformity of the shell-side fluid scouring the tube bundle. Placing the drain hole at the bottom of the U-shaped baffle offers dual physical advantages: Firstly, from a flow dynamics perspective, after the fluid enters through the inlet 14, it scours the tube bundle laterally and gradually flows towards the distal end. The residual fluid, with its kinetic energy gradually decreasing, naturally flows along the flow path towards the bottom wall area away from the inlet 14. The drain hole's placement here perfectly aligns with the fluid's natural trajectory, allowing for smooth discharge of residual fluid. Secondly, from a gravity-assisted drainage perspective, the bottom is the lowest point in the entire U-shaped chamber. Any residual fluid deposited below the chamber due to kinetic energy depletion can be naturally discharged through the bottom drain hole with the aid of gravitational potential difference, completely eliminating fluid dead zones and potential liquid accumulation within the heat exchange space. This synergistic design of placing the drain hole at the bottom of the U-shape provides dual protection against natural flow path drainage and gravity-assisted drainage, ensuring the all-around activity of the fluid and the uniformity of heat exchange within the heat exchange space.

[0033] Specifically, the axial sliding connection structure includes a slider 15 and a groove that cooperate with each other. The slider 15 is fixed to the support member, and the groove is located on the inner wall of the cylinder 7.

[0034] The specific fit between the slider 15 and the groove provides a stable and low-friction axial sliding track for the support, ensuring smooth release of thermal expansion displacement. As the load-bearing base of the internal tube bundle, the support will inevitably experience active axial expansion and contraction displacement as the heat exchange tubes 10 heat up or cool down. Therefore, the support and the slider 15 fixed on it constitute the moving part in the sliding fit. The cylinder 7, as the external pressure-bearing shell, has a relatively delayed temperature change and is fixed by external constraints, constituting the stationary part in the sliding fit. The groove is formed on the inner wall of the cylinder 7, which is the stationary part, providing a stable and low-friction axial sliding track for the slider 15, which is the moving part. This allows the support to slide smoothly backward or forward along the groove on the inner wall of the cylinder 7 when heated, transforming the rigid constraints that might otherwise damage the structure into smooth displacement release and completely eliminating axial thermal stress between the inlet / outlet water pipes and the cylinder.

[0035] Furthermore, to ensure the sliding connection structure remains effective under extreme conditions, the length of the chute extending axially along the cylinder 7 is sufficient to cover the maximum thermal expansion displacement. Specifically, when designing the axial dimensions of the chute, the maximum theoretical thermal expansion difference between the tube bundle and the cylinder, calculated under the highest operating temperature difference conditions for the surface desuperheater, needs to be determined based on this, with a certain safety margin. For example, when the heat exchange tube bundle elongates by several millimeters due to heat, the length of the chute must be greater than this elongation plus the assembly clearance to ensure that under extreme expansion conditions, the slider 15 will still slide within the chute without slipping off the track, leading to support failure or structural jamming. This redundancy in dimensional design provides a solid structural guarantee for the long-term reliable operation of the equipment in harsh environments with large temperature differences, such as supercritical CO2.

[0036] Specifically, heat exchange tube 10 is a finned tube.

[0037] Using finned tubes increases the heat exchange area per unit space, effectively improving heat exchange capacity and reducing the size of the desuperheater. Finned tubes are heat exchange components with a series of finned structures extended from the outer surface of a basic smooth tube. In the limited heat exchange space of a surface desuperheater, relying solely on the outer surface area of ​​the smooth tube for heat exchange results in a very limited heat exchange area per unit space, often requiring extremely long tube passes or a large equipment volume to meet the heat exchange demand. By setting the heat exchange tube 10 as a finned tube, the fins greatly expand the contact area between the fluid and the tube wall, multiplying the heat exchange area per unit space. This effectively improves the heat exchange capacity of the surface desuperheater without increasing the overall size of the equipment, achieving miniaturization and compactness.

[0038] Specifically, the finned tube has a serpentine structure and is equipped with circular fins.

[0039] By optimizing the serpentine tube layout and the specific morphology of the circular fins, the compactness of the tube bundle layout and the heat exchange expansion efficiency of the fins were further improved. The tube routing of the finned tubes was defined as serpentine, with circular fins arranged on it. A serpentine tube refers to a tube layout in which the heat exchange tubes continuously bend and turn in an S-shape or Z-shape along a specific plane within the heat exchange space. Compared to traditional spiral serpentine tubes (i.e., helical coils), serpentine tubes can accommodate more straight tube sections and bends within the same heat exchange space, resulting in a higher tube bend density. Simultaneously, the alternating layout of straight tube sections and bends in the serpentine tubes can continuously disturb and redistribute the shell-side fluid flowing laterally, preventing the formation of a large wake dead zone behind the tube bundle. Furthermore, the circular fins arranged on the finned tubes have a complete annular cross-sectional profile. Compared to helical or strip fins, the circular fins form a uniform extended surface around the tube wall. This not only simplifies the manufacturing process but, more importantly, allows for more uniform flow guidance when supercritical CO2 and other shell-side fluids pass laterally across the tube bundle. This avoids the fluid deflection and local eddy accumulation that can occur with helical fins, thereby optimizing the flow field distribution between the fins and further improving the heat transfer expansion efficiency of the fin surface. This embodiment, through the combination of serpentine orientation and circular fins, achieves synergistic effects in both space utilization and flow field optimization, realizing the optimal configuration of the heat exchange tube 10.

[0040] Specifically, the cylinder 7 is provided with multiple air inlets 14 and air outlets 11, and the air inlets 14 and air outlets 11 are distributed along the axial direction of the cylinder 7.

[0041] By employing a multi-port axial distribution layout, the fluid entering the desuperheater can be more evenly distributed to each heat exchange tube segment 10, improving the overall flow field uniformity. Traditional surface desuperheaters often have only a single inlet and outlet in the middle of the shell. This single-point inlet and outlet layout has significant flow field defects when handling high-flow-rate or long-tube bundle equipment: after the fluid rushes in from a single point, a local flow overload occurs in the heat exchange tube segment near the inlet, resulting in extremely high flow velocity but short heat exchange residence time; as the fluid diffuses further away, its kinetic energy and flow rate gradually decrease, leading to insufficient flow in the distant heat exchange tube segment, or even the formation of a large flow dead zone, resulting in extremely low heat exchange area utilization of the entire equipment. This invention fundamentally reshapes the macroscopic distribution logic of the shell-side fluid by setting multiple inlets 14 and outlets 11 on the shell 7 and distributing these interfaces at intervals along the axial direction of the shell 7. When the fluid to be cooled is simultaneously introduced into the heat exchange space from multiple axially distributed inlets 14, the fluid is uniformly cut into multiple parallel streams. Each stream only needs to flush the heat exchange tubes 10 in its adjacent area, thus avoiding local overload caused by concentrated single-point intake. Simultaneously, the multiple streams advance in parallel within the heat exchange space, ensuring that the heat exchange tubes 10 in each area from the front to the rear of the cylinder 7 receive sufficient and appropriately velocited fluid flushing, completely eliminating the persistent problem of insufficient flow at the far end. Correspondingly, multiple axially distributed outlets 11 also provide a nearby discharge channel for the fluid that has completed heat exchange, avoiding long-distance convergence and mixing interference of the fluid at the outlet end after heat exchange. This multi-point distribution and nearby discharge axial layout mechanism results in a qualitative leap in the uniformity of the flow field throughout the heat exchange space, thereby significantly improving the overall heat exchange efficiency of the surface desuperheater.

[0042] Specifically, the surface desuperheater also includes an inlet pipe 6 and an outlet pipe 5. One end of the heat exchange tube 10 is connected to the inlet pipe 6, and the other end is connected to the outlet pipe 5.

[0043] Clearly defined inlet and outlet pathways for the cooling medium ensure stable circulation within the heat exchange tube 10. The core working principle of the surface-type desuperheater is to allow heat exchange between two fluids at different temperatures without direct contact. The inlet pipe 6 and outlet pipe 5 are the key channels for constructing an independent closed-loop circulation of the cooling medium within the tubes. The cooling medium is introduced into the internal cavity of the heat exchange tube 10 through the inlet pipe 6 and then flows along the direction of the tube. During this flow, the high-temperature fluid to be desuperheated in the shell side is guided by the U-shaped baffle 9 to laterally wash against the outer wall of the heat exchange tube 10. Heat is transferred through the tube wall to the cooling medium inside the tube. After absorbing heat, the cooling medium's temperature rises, and it is finally discharged from the desuperheater through the outlet pipe 5, thus completing a complete heat absorption and discharge cycle. This connection method, with one end inlet and one end outlet, provides a clear flow direction and driving force for the cooling medium, ensuring stable and continuous circulation within the tubes and avoiding the risk of stagnation or localized boiling of the medium within the tubes.

[0044] Specifically, the flow area of ​​the drain hole is smaller than the flow area of ​​the opening.

[0045] By limiting the flow area of ​​the vent hole, the main fluid is ensured to preferentially flush the heat exchange tubes 10 rather than being directly discharged through a short-circuit outlet, thus guaranteeing the sufficiency of the core heat exchange process. In the actual operation of the surface desuperheater, the U-shaped baffle 9 is used to reshape the flow field of the shell-side fluid, forcing the main fluid to flush the heat exchange tube bundle 10 to achieve efficient heat exchange, while the vent hole is used to discharge a small amount of residual fluid to eliminate dead zones. This results in a natural priority difference in flow distribution: flushing the tube bundle must occupy an absolutely dominant flow share, while emptying the residue only requires a very small flow channel. If the flow area of ​​the vent hole is greater than or equal to the flow area of ​​the opening, the fluid to be desuperheated entering from the inlet 14 will preferentially choose the vent hole with the least resistance and shortest path to be discharged directly when it encounters the U-shaped baffle 9, forming a serious fluid short-circuit phenomenon. At this point, most of the fluid escapes without fully flushing the heat exchange tubes 10, and the core heat exchange process is completely suspended, resulting in a sharp drop in heat exchange efficiency. Therefore, this invention establishes a primary-secondary relationship in terms of physical channel size by forcibly limiting the flow area of ​​the vent hole to be smaller than that of the opening. This ensures that the fluid is preferentially guided by the flow direction of the opening to penetrate the heat exchange space and flush the tube bundle. Only a small amount of residual fluid with diminished kinetic energy is discharged through the vent hole, thereby ensuring the sufficiency and effectiveness of the core heat exchange process.

[0046] The present invention also provides a method of using the surface desuperheater as described above, comprising the following steps: introducing the fluid to be desuperheated into the heat exchange space through the air inlet 14; guiding the fluid to be desuperheated to flush the heat exchange tube 10 through the opening of the guide baffle, and discharging the residual fluid through the drain hole; discharging the fluid to be desuperheated through the air outlet 11 after exchanging heat with the cooling medium in the heat exchange tube 10; and sliding the support member along the axial direction of the cylinder 7 through the axial sliding connection structure to adapt to the thermal expansion difference.

[0047] The combination of the opening and drain hole of the guide baffle guides the fluid to flush the tube bundle and discharge residual fluid. Simultaneously, the sliding structure adapts to thermal expansion, achieving the goal of improving heat exchange efficiency and eliminating axial thermal stress at the methodological level. Driven by an external power system, the high-temperature fluid to be desuperheated, such as supercritical carbon dioxide gas, is pressurized along the pipeline to the air inlet 14 on the side wall of the cylinder 7. The fluid rushes at high speed from the air inlet 14 into the heat exchange space enclosed by the support, providing sufficient fluid source and initial kinetic energy for the subsequent flow guidance and heat exchange process. When the fluid to be desuperheated enters the heat exchange space, it does not diffuse randomly or short-circuit against the wall as in traditional desuperheaters, but immediately encounters the interception and guidance of the U-shaped baffle 9. Since the opening of the U-shaped baffle 9 faces the air inlet 14, the fluid is captured by the opening and forced to change its flow direction, laterally flushing the heat exchange tube bundle 10 arranged in the heat exchange space. This flow-guided flushing method greatly increases the contact area and heat exchange time between the fluid and the heat exchange tubes 10, preventing fluid from escaping against the wall. Meanwhile, residual fluid that has lost kinetic energy or fallen into a corner during the flushing process flows naturally along the flow path to an area far from the air inlet 14 and is smoothly discharged through the drain hole on the U-shaped baffle 9. The fluid to be cooled undergoes strong convective heat transfer with the outer wall of the heat exchange tube 10, and the heat is transferred to the cooling medium flowing inside the tube through the tube wall. After the temperature of the cooling fluid drops to the cooling target, it converges to the air outlet 11 of the cylinder 7 and is discharged from the desuperheater to enter the subsequent process cycle. During operation, the cylinder 7 and the internal heat exchange tube 10 are in different temperature fields, which will inevitably produce different degrees of axial thermal expansion. The support (and the entire internal tube bundle it supports) is a moving part that actively generates thermal expansion displacement. Through the slider 15 and other structures set on it, it slides axially with low friction along the groove on the inner wall of the cylinder 7, which is a stationary part. This sliding action transforms the rigid constraint caused by the temperature difference into free displacement release, completely eliminating the axial thermal stress inside the equipment and avoiding structural deformation or damage. The method provided by this invention not only reshapes the flushing and venting path of the fluid in time by combining the opening of the guide baffle with the drain hole, but also provides a continuous thermal stress release mechanism in the operation cycle through the sliding connection structure, thereby fully realizing the invention's purpose of improving heat exchange efficiency and eliminating axial thermal stress at the method level.

[0048] join Figure 1 and Figure 2A surface-type desuperheater includes a cylinder 7, a front cover 1, a rear cover 12, sealing baffles 8, an inlet pipe 6, an outlet pipe 5, and serpentine finned tubes. The front cover 1 and rear cover 12 are fixed to both ends of the cylinder 7. Two sealing baffles 8 are provided, one near the front cover 1 and the other near the rear cover 12 inside the cylinder 7, forming a heat exchange space. The serpentine finned tubes are arranged within the heat exchange space, with one end connected to the inlet pipe 6 and the other end connected to the outlet pipe 5. The cylinder 7 has multiple air inlets 14 and air outlets 11. The front cover 1 includes a flange 2, a flange cover 3, and a sleeve 4. The flange 2 is fixed to the cylinder 7 by double-ended bolts and nuts. The flange 2 and the cylinder 7 are connected... A gasket is provided. The flange cover 3 is welded and fixed to the flange 2. The sleeve 4 is fixed to the flange cover 3. The water inlet pipe 6 and the water outlet pipe 5 pass through a sleeve 4 respectively. The rear end cover 12 is welded and fixed to the cylinder 7. The rear end cover 12 is provided with a hand hole device 13 for the desuperheater maintenance. A U-shaped baffle 9 is provided between the two sealing baffles 8. The two ends of the U-shaped baffle 9 are fixed to the sealing baffles 8. The opening direction corresponds to the air inlet 14 of the cylinder 7. The bottom of the U-shaped baffle 9 has a small hole for exhaust. Two sliders 15 are provided between the sealing baffles 8 and the cylinder 7. The sliders 15 can slide axially in the cylinder 7 to eliminate the axial thermal stress of the water inlet pipe 6 and the water outlet pipe 5. Circular fins are arranged on the serpentine finned tube.

[0049] By arranging U-shaped baffles 9, the supercritical CO2 flow rate through the serpentine finned tubes is increased, and the flow rate adhering to the wall is reduced; multiple air inlets 14 and outlets 11 are set up to make the supercritical CO2 entering the desuperheater flow more evenly through each serpentine finned tube; using serpentine finned tubes as heat exchange tubes results in a larger heat exchange area per unit space, which is significantly increased compared to coiled serpentine tubes, effectively improving heat exchange capacity and reducing the size of the desuperheater.

[0050] Specifically, the cylinder 7 serves as the external pressure-bearing shell of the surface desuperheater. A front cover 1 and a rear cover 12 are fixed to its two ends to form a closed chamber. An air inlet 14 and an air outlet 11 are located on the side wall of the cylinder 7 for the introduction and discharge of the fluid to be desuperheated. In this embodiment, the support is specifically embodied as a sealing baffle 8. The sealing baffle 8 is located inside the cylinder 7 near the front cover 1 and the rear cover 12. The two sealing baffles 8 together enclose a relatively independent heat exchange space, confining the heat exchange tube 10 within this space and preventing the fluid from flowing out directly without heat exchange. It should be understood that the specific form of the support is not limited to a sealing baffle. In other embodiments, it can also be an annular partition or a porous support plate, as long as it can function to enclose the heat exchange space and support the internal components.

[0051] The U-shaped baffle 9 has an opening facing the air inlet 14 and a vent hole away from the air inlet 14. Specifically, the U-shaped baffle 9 is a barrier spanning the heat exchange space, with its two ends fixed to the sealing baffles 8 on both sides, thereby further dividing the heat exchange space into a flow-facing chamber and a core heat exchange zone. The U-shaped baffle 9 is not a completely closed plate, but has a specific layout of openings and vent holes. The opening is positioned facing the air inlet 14, which means that when the fluid to be cooled rushes into the heat exchange space at high speed from the air inlet 14, it will directly collide with the U-shaped baffle 9 and be captured by the opening. This opening layout facing the air inlet 14 forces the fluid, which might otherwise flow along the inner wall of the cylinder 7 or directly seek the shortest path for short-circuiting, to change its flow direction and laterally flush the heat exchange tubes 10 bundle arranged in the heat exchange space, greatly increasing the contact area and heat exchange time between the fluid and the heat exchange tubes 10, thereby effectively avoiding flow along the wall and short-circuiting phenomena, and significantly improving heat exchange efficiency. Meanwhile, the U-shaped baffle 9 also has a vent hole located away from the air inlet 14. During the transverse flow of the fluid through the tube bundle, some fluid kinetic energy will inevitably decrease or it will become trapped in dead zones such as corners of the heat exchange space. The vent hole located away from the air inlet 14 provides a channel for these residual fluids to be discharged. The residual fluid flows naturally along the flow path to the area away from the air inlet 14 and is discharged through the vent hole, thereby completely eliminating dead zones in the heat exchange space and ensuring the fluid activity and heat exchange uniformity of the entire heat exchange space.

[0052] In actual operation of surface desuperheaters, the shell 7 and the internal heat exchange tubes 10 are often in different temperature environments. For example, there is a significant difference between the shell-side fluid temperature and the tube-side cooling medium temperature, resulting in different degrees of axial thermal expansion between the shell 7 and the heat exchange tubes 10. If the support and the shell 7 are connected by a traditional rigid fixed connection, this difference in thermal expansion will be converted into huge axial thermal stress inside the equipment, which can easily lead to structural deformation or even damage under long-term action. This embodiment introduces an axial sliding connection structure between the support and the shell 7, transforming the original rigid constraint into a sliding flexible constraint. When the difference in thermal expansion occurs, the support can slide freely along the axial direction of the shell 7 with the entire internal tube bundle, thereby releasing the displacement and completely eliminating the axial thermal stress generated by the forced constraint. This significantly improves the reliability and service life of the equipment under high temperature difference conditions.

[0053] The surface desuperheater of this invention, through the combination of the opening of the U-shaped baffle 9 and the vent hole, structurally reshapes the flow field distribution of the shell-side fluid, establishing a fluid dynamic mechanism that forces lateral scouring and eliminates dead zones through upstream guidance and far-end venting, thereby achieving a significant improvement in heat exchange efficiency. At the same time, through the axial sliding connection structure, the axial rigid binding between the support and the cylinder 7 is physically released, establishing a stress release mechanism that converts temperature difference displacement into sliding displacement, thereby achieving the complete elimination of axial thermal stress. These two mechanisms are independent yet synergistic, jointly solving the core pain points of low heat exchange efficiency and high thermal stress in existing surface desuperheaters.

[0054] Finally, it should be noted that the embodiments listed above are merely one or more specific manifestations of the technical solution of this invention. Their purpose is to clearly illustrate the concept, principle, and application of this invention through specific examples, and is by no means intended to limit the scope of protection of this invention to these specific embodiments. In fact, the true value of this invention lies in its proposed technical ideas and innovations, rather than its manifestations or implementation methods.

[0055] For those skilled in the art, after thoroughly reading and understanding the technical solution of this invention, they are fully capable of making various changes, modifications, or equivalent substitutions to the specific implementation of the invention based on their own professional knowledge and skills. These changes may include, but are not limited to: adjusting the range of technical parameters, optimizing the algorithm flow to improve efficiency, and replacing some technical components to achieve better compatibility or reduce costs. As long as these modified technical solutions substantially retain the technical features claimed by the original invention, that is, they can still achieve the core functions and effects of this invention, then these changes should be considered to fall within the scope of protection of the pending claims of this invention.

[0056] Furthermore, with the continuous progress and development of technology, new technical means and methods are constantly emerging, which provides ample space for further improvement and perfection of this invention. Therefore, the scope of protection of this invention should also include reasonable and foresightful improvements and extensions based on existing technology. As long as these improvements and extensions do not depart from the basic principles and core concepts of this invention, they should be considered equivalents of this invention and are equally protected by patent rights.

Claims

1. A surface-type desuperheater, characterized in that, It includes a cylinder (7), heat exchange tubes (10), support components and flow guide baffles. The cylinder (7) is provided with an air inlet (14) and an air outlet (11). The support is set inside the cylinder (7) to form a heat exchange space, and the heat exchange tube (10) is arranged in the heat exchange space; The flow guide baffle is set in the heat exchange space and fixed to the support at both ends. The flow guide baffle has an opening facing the air inlet (14) and a drain hole away from the air inlet (14). An axial sliding connection structure is provided between the support member and the cylinder (7) to allow the support member to slide along the cylinder (7) axially.

2. The surface-type desuperheater according to claim 1, characterized in that, The flow guide baffle is a U-shaped baffle (9), with both ends of the U-shaped baffle (9) fixed to the support member, and the opening of the U-shaped baffle (9) facing the air inlet (14).

3. A surface-type desuperheater according to claim 2, characterized in that, The drain hole is located at the bottom of the U-shaped baffle (9) away from the air inlet (14).

4. A surface-type desuperheater according to claim 1, characterized in that, The axial sliding connection structure includes a slider (15) and a groove that cooperate with each other. The slider (15) is fixed to the support and the groove is located on the inner wall of the cylinder (7).

5. A surface-type desuperheater according to claim 1, characterized in that, The heat exchange tube (10) is a finned tube.

6. A surface-type desuperheater according to claim 5, characterized in that, The finned tube has a serpentine structure and is equipped with circular fins.

7. A surface-type desuperheater according to claim 1, characterized in that, The cylinder (7) is provided with multiple air inlets (14) and air outlets (11), and the air inlets (14) and air outlets (11) are distributed along the axial direction of the cylinder (7).

8. A surface-type desuperheater according to claim 1, characterized in that, The surface desuperheater also includes an inlet pipe (6) and an outlet pipe (5). One end of the heat exchange tube (10) is connected to the inlet pipe (6), and the other end is connected to the outlet pipe (5).

9. A surface-type desuperheater according to claim 1, characterized in that, The flow area of ​​the drain hole is smaller than the flow area of ​​the opening.

10. The method of using the surface desuperheater as described in any one of claims 1 to 9, characterized in that, Includes the following steps: The fluid to be cooled is introduced into the heat exchange space through the air inlet (14); The fluid to be cooled is guided through the opening of the baffle to flush the heat exchange tube (10), and the residual fluid is discharged through the drain hole. After the cooling fluid exchanges heat with the cooling medium in the heat exchange tube (10), it is discharged through the air outlet (11); The support member slides along the axial direction of the cylinder (7) through an axial sliding connection structure to accommodate the difference in thermal expansion.

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