Winding pipe type heat exchanger and air separation device

Abstract

The utility model relates to a winding pipe type heat exchanger and an air separation unit, the winding pipe type heat exchanger comprises: a vertically arranged shell pass cylinder, the side wall of which is provided with an upper lateral pipe plate and a lower lateral pipe plate, the top of which is provided with a shell pass outlet, and the bottom of which is provided with a shell pass inlet; the heat exchange tubes are vertically arranged in the shell pass barrel and spirally wound from inside to outside to form a multi-layer spiral tube, each layer of spiral tube is provided with a spiral section and winding-out sections located on the upper side and the lower side, and the ends of the winding-out sections on the upper side and the lower side are bent and then supported on the corresponding upper lateral tube plate and the corresponding lower lateral tube plate; the distribution plate is transversely arranged in the shell pass barrel and is positioned above the shell pass inlet and below the lower lateral tube plate, so that the internal space of the shell pass barrel is divided into an upper part and a lower part; the distribution plate is provided with a plurality of through holes distributed at intervals to communicate a first part of the upper side space and the lower side space and a second part without a through hole, and the second part is located under the lower side winding-out section of each spiral pipe. The heat exchanger can reduce the risk of flow-induced vibration and improve the heat exchange efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of heat exchanger technology, specifically relating to a wound tube heat exchanger and an air separation unit. Background Technology

[0002] Spiral coil heat exchangers, with their advantages of compact structure, large heat transfer area per unit volume, and self-compensation for thermal expansion of heat exchange tubes, have been widely used in fields such as low-temperature methanol washing, low-temperature air separation, aromatics, and propane dehydrogenation. They also offer advantages such as easy scaling up, reduced equipment quantity, lower energy consumption, and significant energy-saving effects.

[0003] On the shell side of a wound tube heat exchanger, the heat exchange tubes are typically arranged in a multi-layered, staggered winding pattern, with numerous positioning elements distributed between the layers. These positioning elements alter the flow state of the shell-side fluid, leading to a more complex flow field. Under continuous fluid impact, this can easily induce flow-induced vibrations.

[0004] The main factors inducing flow-induced vibrations include:

[0005] Fluid elastic instability: Fluid elastic instability is an important theory in fluid mechanics that describes the vibration phenomenon of tube arrays under crossflow. Its core parameter is the ratio of critical flow velocity to crossflow velocity.

[0006] Karman vortex shedding frequency: the ratio of Karman vortex frequency to the natural frequency of the heat exchange tube;

[0007] Turbulent buffeting: The ratio of the buffeting frequency to the natural frequency of the heat exchange tube; the velocity components in the turbulent fluid in the shell side of the heat exchanger periodically transfer energy to the tube wall. When the frequency of these turbulent components is close to or equal to the natural frequency of the heat exchange tube, the tube wall absorbs energy and resonates, thus causing vibration. This phenomenon is called turbulent buffeting.

[0008] Currently, air separation units have been widely used, but they have many characteristics such as long process flow, multiple pressure levels, many compression and heat exchange equipment, and large cooling capacity required for production. Therefore, air separation units have great potential for energy saving and consumption reduction. Utility Model Content

[0009] The first technical problem to be solved by this utility model is to provide a wound tube heat exchanger in view of the current situation of the prior art, so as to reduce the risk of flow-induced vibration and improve heat exchange efficiency.

[0010] The second technical problem to be solved by this utility model is to provide an air separation device with the above-mentioned wound tube heat exchanger in order to achieve energy saving and consumption reduction.

[0011] The technical solution adopted by this utility model to solve the first technical problem mentioned above is: a wound tube heat exchanger, comprising:

[0012] The shell-side cylinder is arranged vertically, with an upper lateral tube sheet and a lower lateral tube sheet arranged one above the other on its side wall. It has a shell-side outlet at the top and a shell-side inlet at the bottom.

[0013] Multiple heat exchange tubes are vertically arranged in the shell-side cylinder and spirally wound from the inside out to form a multi-layer spiral tube. Each layer of spiral tube has a spiral section in the middle and winding sections on the upper and lower sides. The ends of the upper winding section and the lower winding section are bent and supported on their respective upper and lower lateral tube sheets.

[0014] Its characteristic is that it also includes:

[0015] A distribution plate is horizontally placed inside the shell-side cylinder, above the shell-side inlet and below the lower side tube sheet, to divide the internal space of the shell-side cylinder into upper and lower parts, namely an upper space with the aforementioned heat exchange tubes and shell-side outlet, and a lower space with the aforementioned shell-side inlet; and the distribution plate has a first part with a plurality of through holes spaced apart to connect the upper space and the lower space, and a second part without through holes, wherein at least a portion of the second part is located directly below the lower winding section of each helical tube.

[0016] The design of the distribution plate in this utility model has the following technical effects:

[0017] 1. Improve the temperature gradient to prevent the shell-side medium from directly impacting the lower winding section and other key heat exchange elements, effectively reducing thermal stress and avoiding the risk of fatigue damage caused by excessive thermal stress; 2. Change the crossflow velocity to prevent flow-induced vibration caused by aerodynamic instability; 3. Optimize the distribution of the shell-side medium, change the flow pattern of the shell-side medium when entering the shell-side heat exchange, ensure that the shell-side medium can be evenly distributed, effectively avoid the generation of flow deviation and dead zones, and improve the overall heat exchange efficiency.

[0018] Preferably, the first portion occupies a larger proportion of the distribution plate than the second portion, and the vertical projection of the lower winding section of each helical tube falls within the second portion. This ensures the flow rate of the shell-side medium through the distribution plate and further reduces the risk of flow-induced vibration.

[0019] Preferably, it also includes an arc-shaped shell-side nozzle, the upper port of which faces upward and is connected to the shell-side inlet, and the lower port of which is on the same side of the shell-side cylinder as the lower lateral tube sheet.

[0020] The orientation of the lower port of the shell-side nozzle, in conjunction with the position of the openings on the distribution plate, allows the shell-side medium to enter the shell at an optimal angle. This, combined with the flow field created by the openings, further eliminates flow deviation and dead zones. Swirling flow can be formed within the shell-side nozzle, and combined with the guiding effect of the distribution plate, achieves uniform coverage of the shell-side medium within the shell.

[0021] Furthermore, the arrangement of openings on the lower port of the shell-side nozzle and the distribution plate can reduce the flow resistance of the shell-side medium in the shell side, reduce pressure drop loss, achieve smooth flow velocity transition, and reduce energy consumption.

[0022] In the above-mentioned solutions, preferably, the following further includes:

[0023] A crossbeam is placed horizontally within the upper space, above the spiral section;

[0024] The vertically installed boom is connected at its upper end to the crossbeam and at its lower end to the spiral segment, so that the spiral segment is suspended below the crossbeam by the boom.

[0025] This allows the heat exchange tubes to move freely during thermal expansion, further alleviating thermal stress caused by temperature changes and reducing the risk of fatigue damage.

[0026] The natural frequency of heat exchanger tubes is mainly affected by the following factors: diameter, wall thickness, tube arrangement, and unsupported span. Numerous standards and documents have detailed the selection of diameter, wall thickness, and tube arrangement. However, due to their unique structure, wound tube heat exchangers do not employ traditional baffle designs; currently, clamps are often installed at the beginning of the winding section for fixation. However, setting up a fixing structure in the area between the starting point of the winding section and the tube sheet is particularly difficult, making the control of the unsupported span a challenge, especially in lateral tube sheet designs. When the unsupported span of the heat exchanger tubes is large, the natural frequency of the tubes will be low, increasing the risk of flow-induced vibration. Therefore, to solve this technical problem, preferably, a central cylinder is also included, vertically positioned within the upper space, for the heat exchanger tubes to be spirally wound around the outer circumference of the central cylinder.

[0027] The upper winding sections of adjacent spiral tubes and the lower winding sections of adjacent spiral tubes are connected to each other by their respective connectors and then constrained together with the central cylinder.

[0028] By binding the upper and lower outgoing sections together with the central cylinder using connectors, the unsupported span of the heat exchange tubes can be reduced, effectively increasing the natural frequency of the heat exchange tubes and thus fundamentally reducing the risk of flow-induced vibration.

[0029] Preferably, the connector includes a first connector composed of multiple first connecting sleeves, each first connecting sleeve being sleeved on the outer periphery of the corresponding winding section of each layer of spiral tube, and the outer wall surfaces of adjacent inner and outer first connecting sleeves being connected, making the first connector as a whole strip-shaped component. The outer wall surface of the innermost first connecting sleeve is connected to the central cylinder. The design of the first connector composed of multiple first connecting sleeves enables precise control of the unsupported span of the heat exchange tube winding section.

[0030] Furthermore, the connector also includes a second connector composed of multiple second connecting sleeves, each second connecting sleeve being respectively fitted onto the outer periphery of the winding section on the side where the first connecting sleeve of each layer of spiral tube is located, and the outer wall surfaces of adjacent inner and outer second connecting sleeves are connected so that the second connector is strip-shaped as a whole, and the second connector and the first connector are arranged at an angle.

[0031] Furthermore, the included angle is an acute angle.

[0032] The setting of the included angle has the following effects:

[0033] 1) Impact on the stiffness of heat exchanger tube supports:

[0034] The effects of a large included angle:

[0035] If the angle between the first and second connectors is large (close to perpendicular), their support directions are more complementary, forming a more uniform constraint network. This can significantly improve the overall support stiffness of the heat exchange tubes, reduce flexural deformation in unsupported spans, and thus suppress the risk of displacement caused by fluid impact or vibration.

[0036] The effect of a smaller included angle:

[0037] If the included angle is small, it may lead to insufficient local support stiffness, especially in multi-layer wound tube structures, where support blind spots are likely to occur, increasing the possibility of fatigue damage to the heat exchange tubes due to vibration or thermal expansion.

[0038] 2) Compensation capability for thermal expansion displacement:

[0039] Advantages of a large angle:

[0040] The large included-angle design allows the clamps to provide elastic restraint in different dimensions (horizontal and vertical directions). When the heat exchange tubes expand thermally, the elastic deformation of the connecting sleeve can absorb multi-directional displacement, avoiding stress concentration caused by rigid fixing.

[0041] Limitations of small angles:

[0042] If the included angle is too small, the constraint directions of the first and second connecting parts will tend to be the same, which may restrict the free expansion of the heat exchange tube in a specific direction, resulting in the inability to effectively release thermal stress and increasing the risk of damage to the heat exchange tube.

[0043] 3) Suppression effect of flow-induced vibration:

[0044] Relationship between included angle and natural frequency:

[0045] The included angle directly affects the natural frequency of the heat exchange tube. A large included angle design, through multi-point distributed support, shortens the unsupported span, significantly increases the natural frequency of the heat exchange tube, and keeps it away from the main excitation frequency of flow-induced vibration (such as the Karman vortex street frequency or turbulent chattering frequency), thereby avoiding resonance.

[0046] Dispersion of vibrational energy:

[0047] A well-designed angle can guide the fluid impact energy to disperse in the horizontal and vertical directions, reducing the amplitude of local vibrations.

[0048] 4) Structural adaptability and installation / maintenance:

[0049] Matching the included angle with complex structures:

[0050] In wound tube heat exchangers with multiple layers of spiral tubes, the winding directions of different spiral tube layers may differ. By adjusting the included angle, the arrangement characteristics of each spiral tube layer can be adapted to ensure uniform transmission of support force and avoid localized stress concentration caused by structural mismatch.

[0051] The purpose of choosing an appropriate angle:

[0052] Balancing stiffness and flexibility: While ensuring sufficient support stiffness, a certain elastic deformation capacity is retained through the angle design, achieving dual optimization of thermal expansion displacement and vibration suppression.

[0053] Optimize vibration suppression and heat transfer efficiency:

[0054] To avoid wear or leakage of heat exchange tubes due to vibration, and to maintain uniformity of the flow field through stable support, thereby improving the overall heat transfer efficiency.

[0055] Preferably, each winding segment has a first segment extending radially inward from the lateral tube sheet where it is located along the shell-side cylinder, and a second segment extending backward from the inner end of the first segment toward the helical segment, the end of the second segment being connected to the end of the helical segment;

[0056] The first connector is configured to correspond to the second segment, and the second connector is configured to correspond to the first segment.

[0057] The technical solution adopted by this utility model to solve the second technical problem mentioned above is: an air separation device, comprising:

[0058] A molecular sieve adsorber has an inlet for the air to be purified to enter and an outlet for the purified air to exit.

[0059] The heat exchange device has a first heat exchange channel and a second heat exchange channel inside. The inlet of the first heat exchange channel is connected to the outlet of the molecular sieve adsorber.

[0060] A distillation system for separating air has its inlet connected to the outlet of the first heat exchange channel, and its waste nitrogen outlet connected to the inlet of the second heat exchange channel.

[0061] The feature is that it also has a wound tube heat exchanger as described above, wherein the shell-side inlet is connected to the outlet of the second heat exchange channel, and the shell-side outlet is connected to the outlet of the molecular sieve adsorber.

[0062] In operation, the purified air, after being adsorbed by the molecular sieve, is compressed, expanded, and heat-exchanged before entering the distillation system for separation. The waste nitrogen output from the distillation system is further heated by heat exchanger and waste heat steam, and then used as the gas source for molecular sieve regeneration. This process design not only utilizes the preheating of waste nitrogen but also makes use of low-grade waste heat steam, while reducing the energy consumption for regeneration of the molecular sieve adsorber. The advantages of low-temperature preheating utilization are prominent.

[0063] Compared with the prior art, the advantages of this utility model are:

[0064] 1) Uniform fluid distribution, avoiding flow deviation and dead zones: The through holes on the first part of the distribution plate can guide the shell-side medium into the shell side and then evenly distribute it to each layer of spiral tubes, ensuring that the shell-side medium and the heat exchange tubes are in full contact, reducing the decrease in heat exchange efficiency caused by uneven local flow.

[0065] 2) Suppressing Flow-Induced Vibration and Fluid Elastic Instability: Adjusting the size and density of the openings on the distribution plate according to actual operating conditions can effectively reduce the crossflow velocity of the shell-side fluid, preventing it from approaching the critical velocity, thereby suppressing flow instability caused by excessively high velocity. Furthermore, the positional relationship between the lower outflow section and the distribution plate reduces the impact of the shell-side medium on the heat exchange tubes, especially the direct impact on the lower outflow section. This guides the high-speed shell-side medium to a low-resistance region, reducing turbulent chattering and Karman vortex shedding frequencies, and preventing resonance with the natural frequency of the heat exchange tubes.

[0066] 3) Reduce the risk of thermal stress and fatigue damage: The perforated arrangement of the distribution plate can guide the stratified mixing of hot and cold media in the tube side and shell side, reduce the local temperature gradient, and reduce thermal stress.

[0067] 4) Improved heat exchange efficiency and energy saving effect: The perforated arrangement on the distribution plate can reduce the flow resistance of the shell-side medium in the shell side, reduce pressure drop loss, achieve smooth flow velocity transition, and reduce energy consumption; and the uniformly distributed flow field maximizes the contact area between the shell-side medium and the heat exchange tube, enhancing the overall heat transfer efficiency.

[0068] 5) Extended equipment lifespan and reliability: This invention reduces the cumulative effect of flow-induced vibration and thermal stress from the source. The distribution plate design prevents the shell-side medium from directly impacting the heat exchange tube bundle, reducing the risk of material fatigue caused by vibration. At the same time, the distribution plate design also improves the heat exchanger's adaptability to extreme operating conditions (such as sudden flow changes), avoiding local overload through dynamic flow field adjustment, and extending the equipment's service life.

[0069] In summary, the design of the distribution plate in this utility model has the following technical effects:

[0070] 1. Improve the temperature gradient to prevent the shell-side medium from directly impacting the lower winding section and other key heat exchange elements, effectively reducing thermal stress and avoiding the risk of fatigue damage caused by excessive thermal stress; 2. Change the crossflow velocity to prevent flow-induced vibration caused by aerodynamic instability; 3. Optimize the distribution of the shell-side medium, change the flow pattern of the shell-side medium when entering the shell-side heat exchange, ensure that the shell-side medium can be evenly distributed, effectively avoid the generation of flow deviation and dead zones, and improve the overall heat exchange efficiency. Attached Figure Description

[0071] Figure 1 This is a schematic diagram of the structure of the wound tube heat exchanger according to an embodiment of the present utility model;

[0072] Figure 2 for Figure 1 Enlarged view of section A in the middle;

[0073] Figure 3 This is a schematic diagram of the structure of the second connecting sleeve according to an embodiment of the present utility model;

[0074] Figure 4 This is a partial structural cross-sectional view of each of the second connecting sleeves in use according to an embodiment of the present utility model;

[0075] Figure 5 This is a cross-sectional view of the second connecting sleeve according to an embodiment of the present utility model;

[0076] Figure 6 A schematic diagram of the structure of the first connecting sleeve according to an embodiment of this utility model;

[0077] Figure 7 This is a partial structural cross-sectional view of each of the first connecting sleeves in use according to an embodiment of the present utility model;

[0078] Figure 8 This is a cross-sectional view of the first connecting sleeve according to an embodiment of the present utility model;

[0079] Figure 9 This is a partial structural diagram of the central cylinder and support in an embodiment of the present utility model;

[0080] Figure 10 for Figure 9Schematic diagram of the structure in the middle BB direction;

[0081] Figure 11 for Figure 1 Enlarged view of the local structure;

[0082] Figure 12 for Figure 11 Top view;

[0083] Figure 13 for Figure 1 An enlarged view of another local structure;

[0084] Figure 14 This is a schematic diagram of the distribution plate in an embodiment of the present utility model;

[0085] Figure 15 for Figure 1 Another enlarged view of a local structure;

[0086] Figure 16 for Figure 15 Side view;

[0087] Figure 17 for Figure 1 Schematic diagram of the CC-axis structure;

[0088] Figure 18 This is a schematic diagram of the air separation device according to an embodiment of the present invention. Detailed Implementation

[0089] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0090] like Figures 1-18 As shown, this is a preferred embodiment of a wound tube heat exchanger and an air separation unit according to the present invention. The wound tube heat exchanger includes a shell-side cylinder 1, heat exchange tubes 2, a distribution plate 3, a shell-side connecting pipe 4, a crossbeam 5, a hanger 6, a central cylinder 7, and connecting parts.

[0091] The shell-side cylinder 1 is vertically arranged, with an upper lateral tube sheet 11 and a lower lateral tube sheet 12 arranged vertically on its side wall, both located on the left side of the shell-side cylinder 1. The shell-side cylinder 1 has a shell-side outlet 13 at the top and a shell-side inlet 14 at the bottom. The aforementioned shell-side connecting pipe 4 is arc-shaped, with its upper port facing upwards and connecting to the shell-side inlet 14, and its lower port facing left, for the shell-side medium to enter.

[0092] The aforementioned distribution plate 3 is circular and horizontally positioned within the lower space of the shell-side cylinder 1, above the shell-side inlet 14 and below the lower side tube sheet 12. This divides the internal space of the shell-side cylinder 1 into upper and lower sections: an upper space 1a with the shell-side outlet 13 and a lower space 1b with the shell-side inlet 14. The distribution plate 3 has a first section 31 with a plurality of evenly distributed through holes 30 connecting the upper space 1a and the lower space 1b, and a second section 32 without through holes 30. The first section 31 is located on the left side of the distribution plate 3, and both sections 31 and 32 are arranged circumferentially along the distribution plate 3. The proportion of the first section 31 on the distribution plate 3 is greater than that of the second section 32. The diameter and number of the through holes 30 are designed according to actual operating conditions to achieve uniform fluid distribution. Please refer to [link to details]. Figure 14 Meanwhile, in order to support distribution plate 3, such as Figure 1 , 11 As shown in Figures 1 and 12, the lower side of the distribution plate 3 is provided with multiple supporting ribs 33. Each supporting rib 33 is arranged at equal intervals along the circumference, and the upper end of each supporting rib 33 supports the distribution plate 3, while the lower end is supported on the bottom of the shell side cylinder 1 and the periphery of the shell side inlet 14.

[0093] The aforementioned central cylinder 7 is vertically arranged in the upper space 1a, and the lower end of the central cylinder 7 is supported in the center of the distribution plate 3. The upper end of the central cylinder 7 is supported on the side wall of the shell-side cylinder 1 by a number of circumferentially spaced and radially extended crossbeams 5. Specifically, the inner end of each crossbeam 5 is connected to the side wall of the central cylinder 7, and the outer end of each crossbeam 5 is supported on the flange of the side wall of the shell-side cylinder 1.

[0094] Multiple heat exchange tubes 2 are vertically arranged in the upper space 1a and spirally wound around the outer periphery of the central cylinder 7 from the inside out to form a multi-layer spiral tube 20. Each layer of spiral tube 20 has a spiral section 21 in the middle and winding sections on the upper and lower sides. The ends of the upper winding section 22 and the lower winding section 23 are bent and supported on their respective upper lateral tube sheet 11 and lower lateral tube sheet 12, respectively. The projection of the lower winding section 23 of each spiral tube 20 in the vertical direction falls within the second part 32 of the distribution plate 3. At the same time, in this embodiment, each winding section has a first section 2a extending radially inward from the lateral tube sheet it is located along the shell side cylinder 1, and a second section 2b extending toward the spiral section 21 from the inner end of the first section 2a. The end of the second section 2b is connected to the end of the spiral section 21.

[0095] like Figure 1As shown, there are two sets of connectors, used to connect the upper winding section 22 to the central cylinder 7 and the lower winding section 23 to the central cylinder 7, respectively. Each set of connectors includes a first connector 81 composed of multiple first connecting sleeves 810. Each first connecting sleeve 810 is sleeved on the outer periphery of the winding section on the corresponding side of each layer of spiral tube 20, and the outer walls of adjacent inner and outer first connecting sleeves 810 are connected by welding, making the first connector 81 as a whole strip. The outer wall of the innermost first connecting sleeve 810 is connected to the central cylinder 7 through a bracket 83. The bracket 83 is located on the outer wall of the central cylinder 7 and is connected to the outer wall of the innermost first connecting sleeve 810 by welding. Each set of connectors also includes a second connector 82 composed of multiple second connecting sleeves 820. Each second connecting sleeve 820 is respectively fitted onto the outer periphery of the winding section on the side where the first connecting sleeve 810 is located in each layer of spiral tube 20. The outer walls of adjacent inner and outer second connecting sleeves 820 are connected by welding, making the second connector 82 as a whole strip. The second connector 82 and the first connector 81 are arranged at an acute angle. In this embodiment, the first connector 81 corresponds to the second segment 2b of the winding section, and the second connector 82 corresponds to the first segment 2a of the winding section. The mating point of the outer walls of adjacent first connecting sleeves 810 is a first flat surface that fits together; the two first flat surfaces are partially fitted together and partially offset along their own axial direction. The mating point of the outer walls of adjacent second connecting sleeves 820 is a second flat surface that fits together; the two second flat surfaces are partially fitted together and partially offset along their own axial direction. Please refer to [link to details] for further information. Figure 4 , 7 .

[0096] Multiple vertically arranged hangers 6 are provided. The upper end of each hanger 6 is attached to its corresponding crossbeam 5 and can move along the length of the crossbeam 5 under external force. The lower end of each hanger 6 is connected to a spiral segment 21, so that the spiral segment 21 is suspended below the crossbeam 5 by the hanger 6. In this embodiment, similar to the prior art, a spacer strip is provided between the inner and outer spiral segments, and the lower end of the hanger 6 can be connected to the spacer strip. Please refer to [link to details] for further information. Figure 1 , 15 16.

[0097] like Figure 18 As shown, the air separation unit of this embodiment includes a molecular sieve adsorber 91, a heat exchanger 92, a distillation system 93, and the aforementioned heat exchanger.

[0098] The molecular sieve adsorber 91 is prior art, having an inlet for the air to be purified and an outlet for the purified air. The heat exchanger 92 is prior art, internally having a first heat exchange channel and a second heat exchange channel, with the inlet of the first heat exchange channel connected to the outlet of the molecular sieve adsorber 91. The distillation system 93 for separating air includes a conventional distillation column 931 and a argon column 932. The inlet of the distillation system 93 is connected to the outlet of the first heat exchange channel, and the waste nitrogen outlet of the distillation system 93 is connected to the inlet of the second heat exchange channel. The shell-side inlet 14 of the heat exchanger is connected to the outlet of the second heat exchange channel, and the shell-side outlet 13 is connected to the outlet of the molecular sieve adsorber 91.

[0099] After purification and molecular sieve adsorption, the air is compressed, expanded, and heat-exchanged before entering the distillation system 93 for separation. The waste nitrogen output from the distillation system 93 is further heated by waste heat steam through a heat exchanger and used as the gas source for molecular sieve regeneration. This process design not only utilizes the preheating of waste nitrogen but also makes use of low-grade waste heat steam, while reducing the energy consumption for regeneration of the molecular sieve adsorber. The advantages of low-temperature preheating utilization are prominent.

[0100] In the specification and claims of this utility model, terms indicating direction, such as "upper," "lower," "left," "right," "side," "top," and "bottom," are used to describe various exemplary structural parts and elements of this utility model. However, the use of these terms is merely for illustrative purposes and is based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed in this utility model can be arranged in different orientations, these terms indicating direction are for illustrative purposes only and should not be considered as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

[0101] The term "vertical" is also used in the specification and claims of this utility model, meaning basically along the up and down direction, and is not limited to just the vertical direction, but can also be slightly deviated from the vertical direction.

[0102] The term "radial" is also used in the specification and claims of this utility model, meaning basically along the inside and outside direction, and is not limited to the radial direction that passes through the center of the circle, but can also be slightly deviated from the radial direction.

Claims

1. A wound tube heat exchanger, comprising: The shell-side cylinder (1) is arranged vertically, with an upper lateral tube sheet (11) and a lower lateral tube sheet (12) arranged one above the other on its side wall. The shell-side outlet (13) is provided at the top and the shell-side inlet (14) is provided at the bottom. Multiple heat exchange tubes (2) are vertically arranged inside the shell-side cylinder (1) and spirally wound from the inside out to form a multi-layer spiral tube (20). Each layer of spiral tube (20) has a spiral section (21) in the middle and winding sections on the upper and lower sides. The ends of the upper winding section (22) and the lower winding section (23) are bent and supported on their respective upper side tube sheet (11) and lower side tube sheet (12). characterized in that It also includes: The distribution plate (3) is placed horizontally inside the shell-side cylinder (1) and located above the shell-side inlet (14) and below the lower side tube sheet (12) to divide the internal space of the shell-side cylinder (1) into two parts: an upper space (1a) with the heat exchange tube (2) and the shell-side outlet (13) and a lower space (1b) with the shell-side inlet (14); and the distribution plate (3) has a first part (31) with a plurality of through holes (30) spaced apart to connect the upper space (1a) and the lower space (1b) and a second part (32) without through holes (30), at least partially of the second part (32) being located directly below the lower winding section (23) of each spiral tube (20).

2. The spiral wound heat exchanger of claim 1, wherein: The proportion of the first part (31) on the distribution plate (3) is greater than that of the second part (32) on the distribution plate (3), and the projection of the lower winding section (23) of each spiral tube (20) in the vertical direction falls within the second part (32).

3. The spiral wound heat exchanger of claim 1, wherein: It also includes an arc-shaped shell-side connector (4), the upper port of which faces upward and is connected to the shell-side inlet (14), and the lower port of which is on the same side of the shell-side tube sheet (12) as the lower side tube sheet (12).

4. The spiral wound heat exchanger according to any one of claims 1 to 3, characterized in that: It also includes: A crossbeam (5) is placed horizontally within the upper space (1a) above the spiral segment (21); A vertically arranged boom (6) is connected at its upper end to the crossbeam (5) and at its lower end to the spiral section (21), so that the spiral section (21) is suspended below the crossbeam (5) by the boom (6).

5. The spiral wound heat exchanger according to any one of claims 1 to 3, characterized in that: It also includes a central cylinder (7), which is vertically arranged in the upper space (1a) so that the heat exchange tube (2) can be spirally wound around the outer periphery of the central cylinder (7); The upper winding sections (22) of adjacent spiral tubes (20) and the lower winding sections (23) of adjacent spiral tubes (20) are connected by their respective connectors and then constrained together with the central cylinder (7).

6. The spiral wound heat exchanger of claim 5, wherein: The connector includes a first connector (81) composed of multiple first connecting sleeves (810). Each first connecting sleeve (810) is respectively sleeved on the outer periphery of the winding section on the corresponding side of each layer of spiral tube (20), and the outer wall surfaces of adjacent first connecting sleeves (810) are connected so that the first connector (81) is strip-shaped as a whole. The outer wall surface of the innermost first connecting sleeve (810) is connected to the central cylinder (7).

7. The spiral wound heat exchanger of claim 6, wherein: The connector further includes a second connector (82) composed of multiple second connecting sleeves (820). Each second connecting sleeve (820) is respectively sleeved on the outer periphery of the winding section on the side where the first connecting sleeve (810) of each layer of spiral tube (20) is located. The outer wall surfaces of adjacent inner and outer second connecting sleeves (820) are connected so that the second connector (82) is strip-shaped as a whole. The second connector (82) and the first connector (81) are arranged at an angle.

8. The spiral wound heat exchanger of claim 7, wherein: The included angle is an acute angle.

9. The spiral wound heat exchanger of claim 7, wherein: Each outgoing segment has a first segment (2a) extending radially inward from its lateral tube sheet along the shell-side cylinder (1), and a second segment (2b) extending backward from the inner end of the first segment (2a) toward the helical segment (21), the end of the second segment (2b) being connected to the end of the helical segment (21). The first connector (81) is configured to correspond to the second segment (2b), and the second connector (82) is configured to correspond to the first segment (2a).

10. An air separation unit, comprising: Molecular sieve adsorber (91) has an inlet for the air to be purified to enter and an outlet for the purified air to exit. The heat exchange device (92) has a first heat exchange channel and a second heat exchange channel inside, and the inlet of the first heat exchange channel is connected to the outlet of the molecular sieve adsorber (91). A distillation system (93) for separating air has its inlet connected to the outlet of the first heat exchange channel and its waste nitrogen outlet connected to the inlet of the second heat exchange channel. characterized in that It also has a wound tube heat exchanger as described in any one of claims 1 to 9, wherein the shell-side inlet (14) is connected to the outlet of the second heat exchange channel, and the shell-side outlet (13) is connected to the outlet of the molecular sieve adsorber (91).

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