Winding pipe type heat exchanger

Abstract

A winding pipe type heat exchanger comprises a vertically-arranged shell pass barrel, a shell pass inlet connecting pipe and a winding pipe, the central cylinder is vertically arranged in the shell pass cylinder; a plurality of heat exchange tubes; the annular down-flow plate is transversely arranged in the upper part of the shell pass cylinder and below the shell pass inlet connecting pipe, the outer periphery of the down-flow plate is adjacent to or attached to the inner side surface of the shell pass cylinder, and a through hole is defined in the inner periphery of the down-flow plate, so that the central cylinder can penetrate through the through hole; meanwhile, pipe holes are formed in the positions, corresponding to the heat exchange pipes, of the downcomer disc so that the upper ends of the heat exchange pipes can penetrate through the pipe holes, and a plurality of downcomer holes smaller than the pipe holes in size are distributed in the positions, away from the heat exchange pipes, of the downcomer disc at intervals. The outer cofferdam extends upwards from the outer periphery of the downcomer, and the upper end of the outer cofferdam is located below the shell pass inlet connecting pipe; the inner cofferdam extends upwards from the inner periphery of the downcomer, and the upper end of the inner cofferdam is located above the shell pass inlet connecting pipe. According to the utility model, the shell pass medium can be uniformly distributed to each heat exchange tube.

Description

TECHNICAL FIELD

[0001] The utility model belongs to heat exchange technical field, concretely relates to a kind of wound pipe heat exchanger. BACKGROUND

[0002] Wound pipe heat exchanger is widely used in various heat exchange occasions, among them, it is used as the main low-temperature heat exchanger of liquefied natural gas plant, and it plays a key role in natural gas liquefaction process flow. In the heat exchange process, mixed refrigerant is used as shell side medium and flows downward along shell side to realize heat exchange with tube side medium in each heat exchange tube in the form of falling film evaporation. In this heat exchange process, the flow distribution of shell side medium in the heat exchanger has important influence on liquid film formation and heat transfer coefficient. Therefore, how to make shell side medium flow uniformly in the shell side of heat exchanger to improve the heat exchange efficiency of the wound pipe heat exchanger as much as possible is a problem that the person skilled in the art has been pursuing. SUMMARY

[0003] The utility model solves the technical problem that the prior art is present, provide a kind of wound pipe heat exchanger, to make shell side medium can be evenly distributed to each heat exchange tube.

[0004] The utility model discloses the technical scheme for solving the above technical problem: a kind of wound pipe heat exchanger, including:

[0005] Vertically arranged shell side cylinder, the side wall of its upper part is equipped with shell side inlet connection pipe for shell side medium to enter;

[0006] Center cylinder, vertically arranged in the shell side cylinder;

[0007] Multiple heat exchange tubes, vertically arranged in the shell side cylinder, and spiral wound on the outer periphery of the center cylinder from inside to outside to form multiple layers of spiral tubes;

[0008] It is characterized by further comprising:

[0009] Annular downcomer, transversely arranged in the upper part of the shell side cylinder below the shell side inlet connection pipe, the outer periphery of the downcomer is adjacent to or adheres to the inner side of the shell side cylinder, and the inner periphery of the downcomer defines a through hole for the center cylinder to pass through;At the same time, the downcomer is provided with tube holes corresponding to each heat exchange tube, so that the upper end of the corresponding heat exchange tube passes through, and multiple downcomer holes with a size smaller than the tube hole are distributed at positions avoiding the heat exchange tube on the downcomer;

[0010] Peripheral weir extending upward from the outer periphery of the downcomer, and the upper end of the peripheral weir is located below the shell side inlet connection pipe;

[0011] Inner peripheral weir extending upward from the inner periphery of the downcomer, and the upper end of the inner peripheral weir is located above the shell side inlet connection pipe.

[0012] During heat exchange, the shell side medium input from the shell side inlet pipe can accumulate on the downcomer tray between the inner peripheral weir and the outer peripheral weir to form a liquid layer, and since the upper end of the inner peripheral weir is located above the shell side inlet pipe and the upper end of the outer peripheral weir is located below the shell side inlet pipe, the cooperation of the inner peripheral weir, the outer peripheral weir and the downcomer tray can ensure the height of the liquid layer on the downcomer tray, thereby facilitating the uniform distribution of the shell side medium to each heat exchange tube through each downcomer hole.

[0013] In the utility model, the size of the tube hole on the downcomer tray can be adapted to the outer diameter size of the heat exchange tube, so that the edge of the tube hole is adjacent to or adheres to the outer side surface of the heat exchange tube. When the hole diameter of the tube hole on the downcomer tray is slightly larger than the outer diameter of the heat exchange tube, part of the shell side medium on the downcomer tray can flow down through the gap between the edge of the tube hole and the outer side surface of the heat exchange tube.

[0014] The size of the tube hole can also be designed to be larger than the outer diameter size of the heat exchange tube, and the shape of the tube hole can be circular, rectangular, etc., so that the gap between the edge of the tube hole and the outer side surface of the heat exchange tube is larger, thereby facilitating the heat exchange tube to be arranged in the downcomer tray.

[0015] Preferably, the upper end portion of the plurality of heat exchange tubes is at least two groups of tube bundles, and each group of tube bundles is arranged on the downcomer tray in a circumferential direction.

[0016] When the gap between the edge of the tube hole and the outer side surface of the heat exchange tube is large, most of the shell side medium will flow down through the gap between the edge of the tube hole and the outer side surface of the heat exchange tube, resulting in poor fluid distribution effect of the downcomer hole. At this time, in order to improve the uniform distribution effect of the shell side medium, preferably, the outer periphery of each group of tube bundles is surrounded by a shaft, and the shaft has a vertically extending side wall, the lower edge of the side wall is connected to the upper surface of the downcomer tray, and the upper edge of the side wall is located above the shell side inlet pipe. The arrangement of the shaft can avoid the shell side medium flowing down through the tube hole, so that the liquid layer can flow down through the downcomer hole with smaller size and be uniformly distributed to each heat exchange tube.

[0017] Preferably, the side where the shell side inlet pipe is connected to the shell side cylinder is the left side of the shell side cylinder; the tube bundles are arranged on both sides of the central cylinder in front and back; and the downcomer holes are distributed in the left and right side areas of the downcomer tray.

[0018] In order to further improve the uniform distribution effect of the shell side medium, preferably, a plurality of downcomer holes arranged concentrically and in a circumferential direction form a hole group, the number of hole groups is consistent with the number of layers of the spiral tube, each hole group is arranged in a radial direction, and the downcomer holes in each hole group correspond to the spiral tubes in each layer. Thus, the shell side medium can be uniformly distributed to the heat exchange tubes on each layer of spiral tubes.

[0019] Preferably, the number of downcomers in the inner hole group is less than the number of downcomers in the outer hole group in the radial direction. The tube diameter of the outer spiral tube is greater than the tube diameter of the inner spiral tube in the radial direction. The number of downcomers in the inner and outer hole groups in the present application is designed to match the tube diameter of the inner and outer spiral tubes, so that the shell side medium can be more evenly distributed to the heat exchange tubes on each layer of spiral tube.

[0020] In the above scheme, preferably, the outer side surface of the peripheral weir is spaced from the inner side surface of the shell side cylinder to form a first annular gap passing through up and down;

[0021] The inner side surface of the shell side cylinder is provided with a liquid blocking ring which blocks the first annular gap. The liquid blocking ring is located below the shell side inlet connector. The design of the liquid blocking ring can prevent the liquid layer from flowing down through the first annular gap.

[0022] Further, the liquid blocking ring has an upper ring wall extending inwardly from the inner side surface of the shell side cylinder, and a side ring wall extending downwardly from the inner side of the upper ring wall. The upper ring wall is located above the peripheral weir, and the side ring wall is located on the inner side of the peripheral weir and adjacent to or abutting the peripheral weir.

[0023] Preferably, the hole diameter of the through hole on the downcomer tray is greater than the outer diameter of the central cylinder, and the inner side surface of the inner weir is spaced from the side surface of the central cylinder to form a second annular gap passing through up and down. The upper end of the inner weir is constrained with the central cylinder by at least two upper support members arranged circumferentially and spaced. The lower end of the inner weir is constrained with the central cylinder by at least two lower support members arranged circumferentially and spaced. When the shell side medium has a gas phase medium, the gas phase medium can flow downward through the second annular gap to participate in heat exchange.

[0024] In the above schemes, preferably, a baffle is further provided vertically in the shell side cylinder. The baffle plate is spaced from the shell side inlet connector, and the upper edge of the baffle is connected to the side wall above the shell side inlet connector of the shell side cylinder by an upper baffle wall, and the lower edge of the baffle is connected to the side wall below the shell side inlet connector of the shell side cylinder by a lower baffle wall. The design of the baffle can play a role in pre-distribution of the shell side medium, so that the shell side medium input from the shell side inlet connector can flow along the circumference of the shell side cylinder under the blocking action of the baffle to enter the shell side cylinder above the downcomer tray.

[0025] Compared with the prior art, the winding pipe type heat exchanger has the advantages that: the shell side medium input from the shell side inlet pipe can be accumulated on the downcomer tray and between the inner peripheral weir and the outer peripheral weir to form a liquid layer, the height of the liquid layer on the downcomer tray is ensured by cooperation of the inner peripheral weir, the outer peripheral weir and the downcomer tray, and thus the shell side medium is evenly distributed to each heat exchange pipe through each downcomer hole.

[0026] The winding pipe type heat exchanger can realize uniform distribution of the shell side medium and is suitable for being applied to the preparation process of natural liquefied gas as a main low-temperature heat exchanger. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a partial structure sectional view of the winding pipe type heat exchanger of the utility model embodiment one;

[0028] Figure 2 is Figure 1 a sectional view in the direction of A-A;

[0029] Figure 3 is a sectional view of the winding pipe type heat exchanger of the utility model embodiment two. DETAILED DESCRIPTION

[0030] The utility model will be further described in detail in combination with the drawings. Embodiment one:

[0031] As Figure 1 , 2 shown, it is the preferred embodiment one of a winding pipe type heat exchanger of the utility model, and the winding pipe type heat exchanger includes shell side cylinder 1, center cylinder 2, multiple heat exchange pipes 3, fluid distribution member and baffle 8.

[0032] Wherein shell side cylinder 1 is vertically arranged, and the upper end thereof is provided with tube sheet 13 (the lower end thereof is provided with lower tube sheet, and only the structure of the upper part of the heat exchanger is shown in the embodiment, and the lower part of the heat exchanger is of conventional design, so the lower part is not shown in the drawing), and two tube boxes 14 are arranged side by side on the tube sheet 13. At the same time, the side wall of the upper part of the shell side cylinder 1 is provided with shell side inlet pipe 11 for the shell side medium to enter. In the drawing, the shell side inlet pipe 11 is located at the left side of the shell side cylinder 1. It can be understood by those skilled in the art that the shell side outlet pipe is located on the side wall of the lower part of the shell side cylinder 1 and is of conventional design.

[0033] The center cylinder 2 is vertically arranged in the shell side cylinder 1, and the upper end of the center cylinder 2 is supported on the central part of the lower plate surface of the tube sheet 13. It can be imagined that the lower end of the center cylinder 2 is supported on the central part of the upper plate surface of the lower tube sheet (as the conventional design, the lower part is not shown in the drawing).

[0034] A plurality of heat exchange tubes 3 are vertically arranged in the shell side cylinder 1 and are spirally wound on the outer periphery of the central cylinder 2 to form a plurality of layers of spiral tubes 30. In the present embodiment, the upper end portions of the plurality of heat exchange tubes 3 extend vertically upward and are divided into two groups of tube bundles which are distributed on the left and right sides of the central cylinder 2, and the upper end portions of the two groups of tube bundles are supported on the tube plate 13 and are respectively connected to the respective corresponding tube boxes 14.

[0035] The above fluid distribution member comprises a liquid downcomer 4, an inner peripheral weir 6 and an outer peripheral weir 5 which are connected integrally.

[0036] Specifically, the liquid downcomer 4 is annular and is horizontally arranged in the upper portion of the shell side cylinder 1 below the shell side inlet connecting pipe 11. The outer periphery of the liquid downcomer 4 is adjacent to and opposite to the inner side surface of the shell side cylinder 1. The inner periphery of the liquid downcomer 4 defines a circular through hole 40 which has a hole diameter larger than the outer diameter of the central cylinder 2 so as to allow the central cylinder 2 to pass through. Meanwhile, the liquid downcomer 4 is provided with tube holes 41 (the shape of the tube holes 41 is preferably rectangular, and can also be circular) at positions corresponding to the heat exchange tubes 3 so as to allow the upper end portions of the heat exchange tubes 3 to pass through. The liquid downcomer 4 is also provided with a plurality of liquid downcomer holes 42 which are distributed at positions avoiding the heat exchange tubes 3 and have a size smaller than the tube holes 41. In the present embodiment, the liquid downcomer holes 42 are distributed at the front and rear side regions of the liquid downcomer 4. A plurality of liquid downcomer holes 42 which are concentrically and circumferentially distributed form a group of holes, the number of the groups of holes is consistent with the number of layers of the spiral tubes 30, each group of holes is radially distributed, and the liquid downcomer holes 42 in each group of holes are respectively arranged corresponding to the spiral tubes 30 of each layer. Meanwhile, in the radial direction, the number of the liquid downcomer holes 42 in the inner side group of holes is smaller than the number of the liquid downcomer holes 42 in the outer side group of holes. In this way, the number of the liquid downcomer holes in each group of holes can be matched with the tube diameter of the corresponding layer of spiral tubes, that is, the larger the tube diameter of the spiral tube, the more the number of the liquid downcomer holes in the corresponding group of holes.

[0037] The outer peripheral weir 5 extends upward from the outer periphery of the liquid downcomer 4, and the upper end of the outer peripheral weir 5 is located below the shell side inlet connecting pipe 11. The outer side surface of the outer peripheral weir 5 is spaced apart from and opposite to the inner side surface of the shell side cylinder 1 to form a first annular gap 50 which penetrates upward and downward. In order to avoid the shell side medium directly flowing down through the first annular gap, the inner side surface of the shell side cylinder 1 is provided with a liquid blocking ring 12 which blocks the first annular gap 50 from above, and the liquid blocking ring 12 is located below the shell side inlet connecting pipe 11. The liquid blocking ring 12 has an upper ring wall 121 which extends inward from the inner side surface of the shell side cylinder 1, and a side ring wall 122 which extends downward from the inner side edge of the upper ring wall 121. The upper ring wall 121 is located above the outer peripheral weir 5, and the side ring wall 122 is located inside the outer peripheral weir 5 and is adjacent to or abuts against the outer peripheral weir 5.

[0038] The inner weir 6 extends upward from the inner periphery of the downcomer 4, and the upper end of the inner weir 6 is located above the shell-side inlet pipe 11. The inner side of the inner weir 6 is spaced apart from the outer side of the central cylinder 2 to form a second annular gap 60 extending upward and downward; and the upper end of the inner weir 6 is constrained to the central cylinder 2 by at least two upper support members 61 arranged circumferentially and spaced apart (the constraint mode can be fixed by welding), and the lower end of the inner weir 6 is constrained to the central cylinder 2 by at least two lower support members 62 arranged circumferentially and spaced apart (the constraint mode can be fixed by welding), so that the entire fluid distribution member is connected to the central cylinder.

[0039] During heat exchange, the shell-side medium input from the shell-side inlet pipe 11 can accumulate between the inner weir 6 and the outer weir 5 on the downcomer 4 to form a liquid layer. Since the upper end of the inner weir 6 is located above the shell-side inlet pipe 11 and the upper end of the outer weir 5 is located below the shell-side inlet pipe 11 (that is, the inner weir 6 is higher than the outer weir 5), the cooperation of the inner weir 6, the outer weir 5, and the downcomer 4 can ensure the height of the liquid layer on the downcomer 4, thereby facilitating the uniform distribution of the shell-side medium to each heat exchange tube through each downcomer hole.

[0040] To improve the uniform distribution effect of the shell-side medium, the fluid distribution member of the embodiment further includes two vertical shafts 7, each vertical shaft 7 having a vertically extending side peripheral wall 70 surrounding the outer periphery of the corresponding group of tube bundles, and the lower edge of the side peripheral wall 70 being connected to the upper surface of the downcomer 4 and the upper edge of the side peripheral wall 70 being located above the shell-side inlet pipe 11. The design of the vertical shaft 7 can prevent the liquid layer on the downcomer 4 from flowing down through the tube holes 41 on the downcomer 4, so that the liquid layer only flows down through each downcomer hole 42.

[0041] Furthermore, if the shell-side medium has a gas-phase medium, the gas-phase medium can flow upward, a part of the gas-phase medium enters the vertical shaft 7 and flows down through the tube holes 41 on the downcomer 4, and a part of the gas-phase medium enters the second annular gap 60 between the inner weir and the central cylinder and flows downward along the second annular gap 60.

[0042] In the embodiment, to achieve pre-distribution of the shell-side medium, the baffle 8 is vertically arranged in the shell-side cylinder 1 adjacent to the shell-side inlet pipe 11. The baffle 8 is spaced apart from the shell-side inlet pipe 11 to allow the shell-side medium to pass through. The upper edge of the baffle 8 is connected to the side wall above the shell-side inlet pipe 11 of the shell-side cylinder 1 by an upper baffle wall 81, and the lower edge of the baffle 8 is connected to the side wall below the shell-side inlet pipe 11 of the shell-side cylinder 1 by a lower baffle wall 82. The shell-side medium input from the shell-side inlet pipe 11 can enter the shell-side cylinder along the front and rear sides of the baffle 8 under the blocking action of the baffle 8. In the embodiment, the baffle 8 is arranged to be spaced apart from the shell-side inlet pipe 11 to allow the shell-side medium to pass through. Figure 2As shown, the baffle 8 is an arc-shaped plate which is arched from the front and back sides to the center towards the shell side inlet pipe 11, the arc-shaped plate is designed to facilitate the shell side medium to enter the shell side cylinder along the circumferential direction of the arc-shaped plate, and to realize the pre-distribution of the shell side medium to the upper side of the downcomer.

[0043] The winding pipe heat exchanger of the embodiment can be applied to an LNG device for liquefied natural gas production as a main low-temperature heat exchanger. In the heat exchanger, the mixed refrigerant enters the shell side cylinder as the shell side medium from the shell side inlet pipe, the cold energy of the shell side medium is mainly concentrated in the liquid phase medium of the mixed refrigerant, and the cold energy of the gas phase medium is less, and when the liquid layer is formed on the downcomer, the gas-liquid separation is realized, the liquid phase medium flows downward through the downcomer hole, and the gas phase medium flows downward through the pipe hole and the second gap. Embodiment two

[0044] As Figure 3 shown, it is a preferred embodiment two of the winding pipe heat exchanger of the utility model, the embodiment is basically same with the embodiment one, the difference lies in that in the embodiment, two groups of tube bundles are arranged on the two sides of the center cylinder 2 in front and back. Each downcomer hole 42 is distributed in the left and right side areas of the downcomer 4.

[0045] In the specification and claims of the utility model, terms expressing directions, such as "front", "back", "up", "down", "left", "right", "side", "top", "bottom" and the like, are used to describe various example structural parts and elements of the utility model, but these terms are only used for the convenience of description and are determined based on the example orientation shown in the drawings. Since the disclosed embodiments of the utility model can be arranged in different directions, these terms expressing directions should only be used as description and should not be considered as limitation, for example, "up" and "down" are not necessarily limited to the direction opposite or consistent with the direction of gravity.

[0046] In the specification and claims of the utility model, the term "vertical" is also used, which means basically along the up-down direction, and is not limited to only the vertical direction, but can also be slightly inclined relative to the vertical direction.

[0047] In the specification and claims of the utility model, the term "radial" is also used, which means basically along the inside-outside direction, and is not limited to only the radial direction passing through the center of the circle, but can also be slightly inclined relative to the radial direction.

Claims

1. A wound tube heat exchanger, comprising: The shell-side cylinder (1) is arranged vertically, and its upper side wall is provided with a shell-side inlet pipe (11) for the shell-side medium to enter; The central cylinder (2) is vertically arranged inside the shell-side cylinder (1); Multiple heat exchange tubes (3) are vertically arranged inside the shell-side cylinder (1) and spirally wound from the inside to the outside of the central cylinder (2) to form a multi-layer spiral tube (30); Its features It also includes: An annular downcomer plate (4) is horizontally placed inside the upper part of the shell-side cylinder (1) and below the shell-side inlet pipe (11). The outer periphery of the downcomer plate (4) is adjacent to or attached to the inner side of the shell-side cylinder (1). The inner periphery of the downcomer plate (4) defines a through hole (40) for the central cylinder (2) to pass through. At the same time, the downcomer plate (4) is provided with pipe holes (41) corresponding to the positions of each heat exchange tube (3) for the upper end of the corresponding heat exchange tube (3) to pass through. The downcomer plate (4) is provided with a plurality of downcomer holes (42) with a size smaller than the pipe holes (41) at intervals, avoiding the positions of the heat exchange tubes (3). An outer perimeter weir (5) extends upward from the outer perimeter of the descending plate (4), with the upper end of the outer perimeter weir (5) located below the shell-side inlet nozzle (11); An inner weir (6) extends upward from the inner periphery of the descending pan (4), with the upper end of the inner weir (6) located above the shell-side inlet nozzle (11).

2. The wound tube heat exchanger according to claim 1, characterized in that: The upper ends of the multiple heat exchange tubes (3) are divided into at least two groups of tube bundles, and each group of tube bundles is arranged circumferentially on the downcomer plate (4).

3. The wound tube heat exchanger according to claim 2, characterized in that: Each tube bundle is surrounded by a vertical shaft (7), which has a vertically extending side wall (70). The lower edge of the side wall (70) is connected to the upper surface of the downcomer (4), and the upper edge of the side wall (70) is located above the shell-side inlet pipe (11).

4. The wound tube heat exchanger according to claim 2, characterized in that: The side where the shell-side inlet pipe (11) is connected to the shell-side cylinder (1) is the left side of the shell-side cylinder (1); there are two sets of tube bundles, arranged one in front of the other on both sides of the central cylinder (2); the downcomer holes (42) are distributed at intervals on the left and right sides of the downcomer plate (4).

5. The wound tube heat exchanger according to claim 4, characterized in that: A group of holes is formed by multiple descending holes (42) arranged concentrically and circumferentially. The number of holes is the same as the number of layers of the spiral tube (30). Each group of holes is arranged radially and the descending holes (42) in each group are respectively set to correspond to the spiral tube (30) of each layer.

6. The wound tube heat exchanger according to claim 5, characterized in that: In the radial direction, the number of downcomers (42) in the inner hole group is less than the number of downcomers (42) in the outer hole group.

7. The wound tube heat exchanger according to claim 1, characterized in that: The outer side of the outer perimeter weir (5) and the inner side of the shell-side cylinder (1) are spaced apart and form a first annular gap (50) that runs vertically through each other. The inner side of the shell-side cylinder (1) is provided with a liquid-blocking ring (12) that blocks the first annular gap (50), and the liquid-blocking ring (12) is located below the shell-side inlet pipe (11).

8. The wound tube heat exchanger according to claim 7, characterized in that: The liquid-retaining ring (12) has an upper ring wall (121) extending inward from the inner side of the shell-side cylinder (1) and a side ring wall (122) extending downward from the inner side of the upper ring wall (121). The upper ring wall (121) is located above the outer perimeter weir (5), and the side ring wall (122) is located inside the outer perimeter weir (5) and adjacent to or attached to the outer perimeter weir (5).

9. The wound tube heat exchanger according to claim 1, characterized in that: The diameter of the through hole (40) on the liquid dropper (4) is larger than the outer diameter of the central cylinder (2). The inner side of the inner cofferdam (6) and the outer side of the central cylinder (2) are spaced apart to form a second annular gap (60) that runs vertically through each other. The upper end of the inner cofferdam (6) is constrained to the central cylinder (2) by at least two upper support members (61) arranged circumferentially at intervals. The lower end of the inner cofferdam (6) is constrained to the central cylinder (2) by at least two lower support members (62) arranged circumferentially at intervals.

10. The wound tube heat exchanger according to any one of claims 1 to 9, characterized in that: It also includes a baffle (8) vertically disposed inside the shell-side cylinder (1), the surface of the baffle (8) being spaced apart from the shell-side inlet pipe (11), and the upper edge of the baffle (8) being connected to the side wall above the shell-side inlet pipe (11) of the shell-side cylinder (1) through an upper baffle wall (81), and the lower edge of the baffle (8) being connected to the side wall below the shell-side inlet pipe (11) of the shell-side cylinder (1) through a lower baffle wall (82).

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