A coiled-tube heat exchanger for saturated alkane phase change conditions

Abstract

The present invention discloses a coiled tube heat exchanger for saturated alkane phase change working conditions, relates to the technical field of heat exchangers, and solves the problem of poor heat exchange effect of existing heat exchangers. The heat exchanger comprises an outer tube, a core tube and multi-layer heat exchange tubes. The multi-layer heat exchange tubes are interlaced in a spiral shape and arranged in the space between the outer tube and the core tube. The output end of the multi-layer heat exchange tube is connected to an expander tube that can freely expand the internal space. A plurality of movable plates are fixed to the outer array of the expander tube. A support plate is provided on the outer side of the movable plate. One end of the support plate is fixedly connected to the outer wall of the core tube. The present invention utilizes a synchronous expansion mechanism to drive the movable plate to stretch the expander tube, thereby changing the passage space of the fluid medium inside the expander tube, and indirectly changing the inner diameter of the pipe at the outlet end of the heat exchange tube, so that the fluid that reaches heat absorption saturation inside can be quickly discharged at the outlet end of the heat exchange tube.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, in particular to a coiled tube heat exchanger used in saturated alkane phase change working conditions. Background Art

[0002] In the heat exchange process of saturated alkanes such as propane, n-butane, and isobutane in petrochemical companies, the medium is characterized by high temperature and high pressure in production conditions. Furthermore, the heat exchange process requires the reaction products (high-temperature saturated alkanes) to be exchanged with the reaction feed (low-temperature, hydrogen-containing hydrocarbon mixture) with an end-to-end temperature difference of less than 50°C. This heat exchange process has a high heat load, and the hot and cold media undergo a liquid-to-gas phase transition within the heat exchange equipment. This heat exchange process has limited space, making it impossible to use multiple conventional shell-and-tube heat exchangers in series.

[0003] The inventors carefully analyzed the heat exchange process and various heat exchanger types, and combined this with equipment material selection to select a coiled-tube heat exchanger with high heat transfer efficiency, a compact structure, and the ability to allow for phase change within the device. This heat exchanger boasts high heat transfer efficiency, low investment costs, minimal thermal stress, minimal hot-end temperature differences, and high heat recovery. Its unique spirally wound, thin-walled heat exchange tubes balance thermal stresses and save on expansion joint costs.

[0004] However, the existing coiled-tube heat exchanger has a higher heat transfer efficiency during heat exchange due to the unique winding structure of the spirally wound tubes. Even at the beginning of heat exchange, due to the large temperature difference, the fluid medium in the spirally wound tube will absorb too much heat when it has only flowed halfway. That is to say, the heat transfer effect of the fluid medium will be reduced at the rear end of the flow. For this reason, we propose a coiled-tube heat exchanger for saturated alkane phase change working conditions. Summary of the Invention

[0005] The object of the present invention is to provide a coiled-tube heat exchanger for saturated alkane phase change conditions, which prevents the liquid medium in the heat exchange tube from absorbing too much heat and can improve the heat exchange effect of the fluid medium at the rear end of the flow, so as to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a coil-wound heat exchanger for saturated alkane phase change conditions, comprising a heat exchanger outer tube, a core tube and a multi-layer heat exchange tube, wherein the multi-layer heat exchange tube is interlaced and wound in a spiral shape and arranged in the space between the heat exchanger outer tube and the core tube, and the output end of the multi-layer heat exchange tube is connected to an expander tube that can freely expand the internal space, and a plurality of movable plates are fixed to the outer array of the expander tube, and a support plate is provided on the outer side of the movable plate, and one end of the support plate is fixedly connected to the outer wall of the core tube, and a plurality of groups of synchronous expansion mechanisms are provided on the support plate for changing the passage space of the fluid medium inside the expander tube.

[0007] Preferably, the synchronous expansion mechanism includes a movable screw, a fixed screw sleeve, a first limit plate, an active bevel gear, a driven bevel gear and a synchronous transmission assembly, one end of the movable screw is fixedly connected to the end of the movable piece away from the wall expansion tube, the fixed screw sleeve is rotatably connected to the first limit plate, the first limit plate is fixed to the support plate, the movable screw is threadedly connected to the inner side of the fixed screw sleeve, the active bevel gear is transmission-connected to the synchronous transmission assembly, the synchronous transmission assembly is mounted on the support plate, the driven bevel gear is fixed to the outer side of the fixed screw sleeve and meshingly connected with the active bevel gear, and multiple multi-layer heat exchange tubes can be expanded and adjusted at the same time through the synchronous expansion mechanism.

[0008] Preferably, the synchronous transmission assembly includes a transmission ring, a planetary gear, a transmission gear and a combined drive mechanism, the transmission ring is rotatably connected to the support plate through a bearing, a plurality of internal teeth are evenly distributed on the inner side of the transmission ring, and the plurality of planetary gears are meshed with the transmission ring through the internal teeth, a plurality of external teeth are evenly distributed on the outer side of the transmission ring, and the transmission gear is meshed with the transmission ring through the external teeth, one end of the central axis of the planetary gear is fixedly connected to the active bevel gear, the transmission gear is provided with multiple groups, and the central axes of the plurality of groups of transmission gears are rotatably connected to the support plate through bearings, the output end of the combined drive mechanism is transmission-connected to the plurality of transmission gears, and the synchronous transmission assembly can provide power for the movement of the plurality of moving screws.

[0009] Preferably, the combined drive mechanism includes a drive gear ring, a drive gear and a power device. The drive gear ring is rotatably connected to the outside of the core barrel through a bearing. The number of the drive gears is equal to the number of the transmission gears and there are multiple drive gears. The multiple drive gears are all meshed and connected with the outside of the drive gear ring. The power device is installed on the core barrel, and the combined drive mechanism can provide power for the operation of multiple sets of synchronous expansion mechanisms.

[0010] Preferably, the power device includes a dual-axis stepper motor, a connecting mechanism and a clutch mechanism. One of the output ends of the dual-axis stepper motor is connected to one of the driving gears through the connecting mechanism, and the other output end of the dual-axis stepper motor is connected to a cleaning component for cleaning the inner side of the multi-layer heat exchange tube through the connecting mechanism. The clutch mechanism is arranged on the inner side of the core barrel and its output end is fixedly connected to the dual-axis stepper motor, and power can be provided by the power device.

[0011] Preferably, the connecting mechanism includes an internal spline and an external spline, the internal spline is respectively fixed on the two output ends of the dual-axis stepper motor, and the external spline is respectively fixedly connected to the central axis of the driving gear and the input end of the cleaning component, and the power unit and the combined drive mechanism can be connected through the connecting mechanism.

[0012] Preferably, the clutch mechanism includes an electric push rod and a sliding frame, the electric push rod is installed inside the core barrel, a sliding groove is provided on the core barrel, the sliding frame is fixedly connected to the output end of the electric push rod, the sliding frame is slidably connected to the core barrel through the sliding groove, the bottom of the dual-axis stepper motor is fixedly connected to one end of the sliding frame away from the electric push rod, and the clutch mechanism can provide power for the movement of the dual-axis stepper motor.

[0013] Preferably, the cleaning assembly includes a brush wall plate, an L-shaped frame, a rotating gear ring and a power gear. The brush wall plate is fixedly connected to the outer side of the rotating gear ring through the L-shaped frame. The rotating gear ring is rotatably connected to the outer side of the core barrel through a bearing. One side of the brush wall plate is fitted with the inner outer wall of the multi-layer heat exchange tube. The power gear is meshed with the rotating gear ring. The external spline is fixed in the middle hole of the power gear. The outer side of the external spline is rotatably connected with a second limit plate. The second limit plate is fixed on the outer wall of the core barrel. The inner dirt of the multi-layer heat exchange tube can be cleaned through the cleaning assembly.

[0014] Preferably, the brush wall plates and the L-shaped frames are each provided with four groups, and the four groups of the brush wall plates and the L-shaped frames are distributed in a ring array to enhance the cleaning effect.

[0015] Preferably, the wall expansion tube is made of a tensile-resistant and high-temperature-resistant elastic rubber material, and welding heads are integrally fixed to both ends of the wall expansion tube through sealing rings. By using a wall expansion tube made of this material, the tube diameter can be easily adjusted.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention cooperates with the designed wall expansion tube, movable plate and synchronous expansion mechanism, and can use the synchronous expansion mechanism to drive the movable plate to stretch the wall expansion tube, thereby changing the passage space of the fluid medium inside the wall expansion tube, and indirectly changing the inner diameter of the pipe at the outlet end of the heat exchange tube, so that the fluid that reaches heat absorption saturation inside can be quickly discharged at the outlet end of the heat exchange tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 It is a structural schematic diagram of the present invention from another perspective;

[0020] Figure 3 is a side view of the present invention;

[0021] Figure 4 This is a structural diagram of the synchronous expansion mechanism of the present invention;

[0022] Figure 5 This is a structural diagram of the synchronous transmission assembly of the present invention;

[0023] Figure 6 This is a structural diagram of the combined drive mechanism of the present invention;

[0024] Figure 7 This is a schematic structural diagram of the power unit of the present invention;

[0025] Figure 8 It is a schematic structural diagram of the clutch mechanism and the connecting mechanism of the present invention;

[0026] Figure 9 This is a schematic structural diagram of the cleaning component of the present invention;

[0027] Figure 10 for Figure 7 Enlarged view of area A in the middle.

[0028] In the figure: 1-heat exchanger outer tube; 2-core tube; 3-multi-layer heat exchange tube; 4-expanding wall tube; 5-movable plate; 6-support plate; 7-synchronous expansion mechanism; 8-moving screw; 9-fixed screw sleeve; 10-first limit plate; 11-driving bevel gear; 12-driven bevel gear; 13-synchronous transmission assembly; 14-transmission ring; 15-planetary gear; 16-transmission gear; 17-joint drive mechanism; 18-driving gear ring; 19-driving gear; 20-power unit; 21-dual-axis stepping motor; 22-connecting mechanism; 23-clutch mechanism; 24-cleaning assembly; 25-internal spline; 26-external spline; 27-electric push rod; 28-sliding frame; 29-sliding groove; 30-brush wall plate; 31-L-shaped frame; 32-rotating gear ring; 33-power gear; 34-second limit plate. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] Example 1

[0031] like Figure 1-Figure 3 As shown in the figure, a coiled heat exchanger for saturated alkane phase change working conditions includes a heat exchanger outer tube 1, a core tube 2 and a multi-layer heat exchange tube 3. The multi-layer heat exchange tube 3 is interlaced in a spiral shape and is arranged in the space between the heat exchanger outer tube 1 and the core tube 2. The output end of the multi-layer heat exchange tube 3 is connected to a wall expansion tube 4 that can freely expand the internal space. A plurality of movable sheets 5 are fixed to the outer array of the wall expansion tube 4. A support plate 6 is provided on the outer side of the movable sheet 5. One end of the support plate 6 is fixedly connected to the outer wall of the core tube 2. The support plate 6 is provided with a plurality of groups for changing the wall expansion tube The synchronous expansion mechanism 7 of the space through which the internal fluid medium passes, through the designed mutual cooperation of the wall expansion tube 4, the movable piece 5 and the synchronous expansion mechanism 7, during normal heat exchange, the inner diameter of the wall expansion tube 4 is kept at a certain value. When the internal fluid medium flows halfway and reaches heat absorption saturation, the synchronous expansion mechanism 7 can be used to drive the movable piece 5 to stretch the wall expansion tube 4, thereby changing the passage space of the internal fluid medium of the wall expansion tube 4 and indirectly changing the inner diameter of the pipe at the outlet end of the heat exchange tube, so that the fluid that has reached heat absorption saturation can be quickly discharged at the outlet end of the heat exchange tube.

[0032] Among them, such as Figure 2 and Figure 4 As shown, in order to be able to simultaneously expand and adjust multiple multi-layer heat exchange tubes 3, the synchronous expansion mechanism 7 includes a movable screw 8, a fixed screw sleeve 9, a first limiting plate 10, an active bevel gear 11, a driven bevel gear 12 and a synchronous transmission assembly 13. One end of the movable screw 8 is fixedly connected to the end of the movable piece 5 away from the wall expansion tube 4, the fixed screw sleeve 9 is rotatably connected to the first limiting plate 10, the first limiting plate 10 is fixed to the support plate 6, the movable screw 8 is threadedly connected to the inner side of the fixed screw sleeve 9, the active bevel gear 11 is transmission-connected to the synchronous transmission assembly 13, the synchronous transmission assembly 13 is installed on the support plate 6, and the driven bevel gear 12 is fixed to the outer side of the fixed screw sleeve 9 and is meshed with the active bevel gear 11.

[0033] At the same time, if Figure 5As shown, in order to provide power for the movement of multiple moving screws 8, the synchronous transmission assembly 13 includes a transmission ring 14, a planetary gear 15, a transmission gear 16 and a joint drive mechanism 17. The transmission ring 14 is rotatably connected to the support plate 6 through a bearing. A plurality of internal teeth are evenly distributed on the inner side of the transmission ring 14. The plurality of planetary gears 15 are meshed with the transmission ring 14 through the internal teeth. A plurality of external teeth are evenly distributed on the outer side of the transmission ring 14. The transmission gear 16 is meshed with the transmission ring 14 through the external teeth. One end of the central axis of the planetary gear 15 is fixedly connected to the active bevel gear 11. There are multiple groups of transmission gears 16, and the central axes of the multiple groups of transmission gears 16 are rotatably connected to the support plate 6 through bearings. The output end of the joint drive mechanism 17 is transmission-connected to the multiple transmission gears 16.

[0034] In addition, if Figure 1 and Figure 6 As shown, in order to provide power for the operation of multiple sets of synchronous expansion mechanisms 7, the combined drive mechanism 17 includes a drive gear ring 18, a drive gear 19 and a power device 20. The drive gear ring 18 is rotatably connected to the outer side of the core barrel 2 through a bearing. The number of drive gears 19 is equal to that of the transmission gears 16 and there are multiple drive gears 19. The multiple drive gears 19 are all engaged with the outer side of the drive gear ring 18, and the power device 20 is installed on the core barrel 2.

[0035] At the same time, if Figure 7 As shown, in order to provide power, the power device 20 includes a dual-axis stepper motor 21, a connecting mechanism 22 and a clutch mechanism 23. One of the output ends of the dual-axis stepper motor 21 is connected to one of the driving gears 19 through the connecting mechanism 22, and the other output end of the dual-axis stepper motor 21 is connected to a cleaning component 24 for cleaning the inner dirt of the multi-layer heat exchange tube 3 through the connecting mechanism 22. The clutch mechanism 23 is arranged on the inner side of the core tube 2 and its output end is fixedly connected to the dual-axis stepper motor 21.

[0036] In addition, the wall expansion tube 4 is made of tensile-resistant and high-temperature-resistant elastic rubber material, and welding heads are integrally fixed to both ends of the wall expansion tube 4 through sealing rings. The wall expansion tube 4 made of this material can be easily adjusted for diameter.

[0037] When the wall expansion tube 4 is adjusted: in actual use, the input and output ends of the multi-layer heat exchange tube 3 are connected to the two ends of the heat exchanger. During normal heat exchange, the internal fluid medium of the multi-layer heat exchange tube 3 is circulated and discharged through an external drainage device. In the specific heat exchange process, the inner diameter of the wall expansion tube 4 is a fixed value. When the internal fluid medium flows halfway and reaches heat absorption saturation, the power device 20 can provide power to drive one of the drive gears 19 to rotate. The drive gear 19 then drives the drive gear ring 18 to rotate to drive the remaining drive gears 19 to rotate together. When multiple drive gears 19 rotate together, they will simultaneously drive multiple transmission gears 16 to rotate together. The multiple transmission gears 16 are driven by the external toothed belt of the transmission ring 14. The dynamic transmission ring 14 rotates, and the transmission ring 14 drives multiple planetary gears 15 to rotate through the internal teeth. The planetary gears 15 drive the active bevel gear 11 to rotate, and the active bevel gear 11 drives the driven bevel gear 12 to rotate. The driven bevel gear 12 drives the fixed screw sleeve 9 to rotate, and the fixed screw sleeve 9 drives the movable screw 8 to move outward, so that the movable screw 8 drives the movable piece 5 to pull the wall expansion tube 4. At the same time, under the simultaneous action of multiple movable pieces 5, the wall expansion tube 4 is evenly pulled, thereby changing the passage space of the fluid medium inside the wall expansion tube 4, indirectly changing the inner diameter of the pipe at the outlet end of the heat exchange tube, so that the fluid that reaches heat absorption saturation inside can be quickly discharged at the outlet end of the heat exchange tube through the external drainage device.

[0038] Example 2

[0039] As shown Figure 2 and 7 As shown, this embodiment further illustrates Example 1. The power device 20 shown in the figure includes a dual-axis stepper motor 21, a connecting mechanism 22 and a clutch mechanism 23. One of the output ends of the dual-axis stepper motor 21 is connected to one of the driving gears 19 through the connecting mechanism 22, and the other output end of the dual-axis stepper motor 21 is connected to a cleaning component 24 for cleaning the inner dirt of the multi-layer heat exchange tube 3 through the connecting mechanism 22. The clutch mechanism 23 is arranged on the inner side of the core tube 2 and its output end is fixedly connected to the dual-axis stepper motor 21. Power can be provided by the power device 20.

[0040] Among them, Figure 10 As shown, in order to facilitate the connection between the power unit 20 and the combined drive mechanism 17, the connecting mechanism 22 includes an internal spline 25 and an external spline 26. The internal spline 25 is respectively fixed on the two output ends of the dual-axis stepper motor 21, and the external spline 26 is respectively fixedly connected to the central axis of the drive gear 19 and the input end of the cleaning component 24.

[0041] In addition, if Figure 8As shown, in order to provide power for the movement of the dual-axis stepper motor 21, the clutch mechanism 23 includes an electric push rod 27 and a sliding frame 28. The electric push rod 27 is installed inside the core barrel 2. A sliding groove 29 is provided on the core barrel 2. The sliding frame 28 is fixedly connected to the output end of the electric push rod 27. The sliding frame 28 is slidably connected to the core barrel 2 through the sliding groove 29. The bottom of the dual-axis stepper motor 21 is fixedly connected to the end of the sliding frame 28 away from the electric push rod 27.

[0042] When power is distributed to the synchronous expansion mechanism 7: by starting the electric push rod 27, the electric push rod 27 drives the sliding frame 28 to slide in the sliding groove 29, and the sliding frame 28 drives the dual-axis stepping motor 21 to move, so that the internal spline 25 on one output end of the dual-axis stepping motor 21 slides into the external spline 26 on one of the drive gears 19, thereby connecting one output end of the dual-axis stepping motor 21 to the joint drive mechanism 17, and then starting the dual-axis stepping motor 21, its output shaft will transmit power to the drive gear 19, and the drive gear 19 will further transmit the power through the joint drive mechanism 17 and the synchronous transmission assembly 13.

[0043] Example 3

[0044] like Figure 7 and Figure 9 As shown, this embodiment further illustrates Example 2. The power device 20 shown in the figure includes a dual-axis stepper motor 21, a connecting mechanism 22 and a clutch mechanism 23. One of the output ends of the dual-axis stepper motor 21 is connected to one of the driving gears 19 through the connecting mechanism 22. The other output end of the dual-axis stepper motor 21 is connected to a cleaning component 24 for cleaning the dirt inside the multi-layer heat exchange tube 3 through the connecting mechanism 22. The clutch mechanism 23 is provided on the inner side of the core barrel 2 and its output end is fixedly connected to the dual-axis stepper motor 21. The cleaning component 24 includes a brush wall plate 30, L-shaped frame 31, rotating gear ring 32 and power gear 33, the brush wall plate 30 is fixedly connected to the outer side of the rotating gear ring 32 through the L-shaped frame 31, the rotating gear ring 32 is rotatably connected to the outer side of the core barrel 2 through the bearing, one side of the brush wall plate 30 is in contact with the inner and outer walls of the multi-layer heat exchange tube 3, the power gear 33 is meshed with the rotating gear ring 32, the external spline 26 is fixed in the middle hole of the power gear 33, the outer side of the external spline 26 is rotatably connected with the second limit plate 34, the second limit plate 34 is fixed on the outer wall of the core barrel 2, and the dirt on the inner side of the multi-layer heat exchange tube 3 can be cleaned through the cleaning component 24.

[0045] Among them, Figure 9 As shown, in order to enhance the cleaning effect, four groups of brush wall plates 30 and L-shaped frames 31 are provided, and the four groups of brush wall plates 30 and L-shaped frames 31 are distributed in a ring array.

[0046] When cleaning the multi-layer heat exchange tube 3: by starting the electric push rod 27, the electric push rod 27 drives the sliding frame 28 to slide in the sliding groove 29, and the sliding frame 28 drives the dual-axis stepper motor 21 to move, so that the internal spline 25 on the other output end of the dual-axis stepper motor 21 slides into the external spline 26 on the power gear 33, so that the other output end of the dual-axis stepper motor 21 is connected to the power gear 33, and then the dual-axis stepper motor 21 is started, and its output shaft will transmit power to the power gear 33, and the power gear 33 will further drive the rotating gear ring 32 to rotate, and the rotating gear ring 32 drives the brush wall plate 30 fixed thereon to rotate, and the brush wall plate 30 cleans the dirt on the inner and outer walls of the multi-layer heat exchange tube 3, so that the brush wall plate 30 brushes off the dirt on the inner and outer walls of the multi-layer heat exchange tube 3, completing the automatic cleaning work.

[0047] In this solution, the dual-axis stepper motor 21 is preferably of the TK-RC395SH model, which has an IP68 protection rating and is suitable for use in underwater locations. The power supply interface of the motor is connected to the power supply system of the heat exchanger through a switch, and the operating circuit is a conventional motor forward and reverse control program. The electric push rod 27 is preferably of the ANT-26 model, and the circuit operation is an existing conventional circuit. The circuits and controls involved in this solution are all existing technologies and will not be elaborated on here.

[0048] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0049] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A coiled heat exchanger for saturated alkane phase change operation, comprising a heat exchanger outer tube (1), a core tube (2) and multi-layer heat exchange tubes (3), wherein the multi-layer heat exchange tubes (3) are interlaced and wound in a spiral shape and arranged in the space between the heat exchanger outer tube (1) and the core tube (2), and characterized in that: The output end of the multi-layer heat exchange tube (3) is connected to a wall expansion tube (4) capable of freely expanding the internal space, a plurality of movable plates (5) are fixed in an array on the outside of the wall expansion tube (4), a support plate (6) is provided on the outside of the movable plate (5), one end of the support plate (6) is fixedly connected to the outer wall of the core tube (2), and a plurality of groups of synchronous expansion mechanisms (7) for changing the passage space of the fluid medium inside the wall expansion tube (4); The synchronous expansion mechanism (7) comprises a movable screw (8), a fixed screw sleeve (9), a first limiting plate (10), a driving bevel gear (11), a driven bevel gear (12) and a synchronous transmission assembly (13), one end of the movable screw (8) is fixedly connected to the end of the movable piece (5) away from the wall expansion tube (4), the fixed screw sleeve (9) is rotatably connected to the first limiting plate (10), the first limiting plate (10) is fixed to the support plate (6), the movable screw (8) is threadedly connected to the inner side of the fixed screw sleeve (9), the driving bevel gear (11) is transmission-connected to the synchronous transmission assembly (13), the synchronous transmission assembly (13) is mounted on the support plate (6), and the driven bevel gear (12) is fixed to the outer side of the fixed screw sleeve (9) and meshed with the driving bevel gear (11).

2. A coil-wound heat exchanger for saturated alkane phase change operation according to claim 1, characterized in that: The synchronous transmission assembly (13) comprises a transmission ring (14), a planetary gear (15), a transmission gear (16) and a combined drive mechanism (17), wherein the transmission ring (14) is rotatably connected to the support plate (6) via a bearing, a plurality of internal teeth are evenly distributed on the inner side of the transmission ring (14), and the plurality of planetary gears (15) are meshed and connected to the transmission ring (14) via the internal teeth, a plurality of external teeth are evenly distributed on the outer side of the transmission ring (14), and the transmission gear (16) is meshed and connected to the transmission ring (14) via the external teeth, one end of the central axis of the planetary gear (15) is fixedly connected to the active bevel gear (11), a plurality of transmission gears (16) are provided, and the central axes of the plurality of transmission gears (16) are rotatably connected to the support plate (6) via bearings, and the output end of the combined drive mechanism (17) is transmission-connected to the plurality of transmission gears (16).

3. The coil-wound heat exchanger for saturated alkane phase change operation according to claim 2, characterized in that: The combined drive mechanism (17) includes a drive gear ring (18), a drive gear (19) and a power device (20), wherein the drive gear ring (18) is rotatably connected to the outer side of the core barrel (2) via a bearing, the number of the drive gears (19) is equal to the number of the transmission gears (16) and a plurality of the drive gears (19) are provided, and the plurality of drive gears (19) are all meshed and connected with the outer side of the drive gear ring (18), and the power device (20) is mounted on the core barrel (2).

4. A coiled-tube heat exchanger for saturated alkane phase change operation according to claim 3, characterized in that: The power device (20) includes a dual-axis stepper motor (21), a connecting mechanism (22) and a clutch mechanism (23). One of the output ends of the dual-axis stepper motor (21) is connected to one of the driving gears (19) through the connecting mechanism (22). The other output end of the dual-axis stepper motor (21) is connected to a cleaning component (24) for cleaning dirt on the inner side of the multi-layer heat exchange tube (3) through the connecting mechanism (22). The clutch mechanism (23) is arranged on the inner side of the core barrel (2) and its output end is fixedly connected to the dual-axis stepper motor (21).

5. The coil-wound heat exchanger for saturated alkane phase change operation according to claim 4, characterized in that: The connecting mechanism (22) comprises an inner spline (25) and an outer spline (26), wherein the inner spline (25) is respectively fixed to the two output ends of the dual-axis stepper motor (21), and the outer spline (26) is respectively fixedly connected to the central axis of the driving gear (19) and the input end of the cleaning component (24).

6. The coiled tube heat exchanger for saturated alkane phase change operation according to claim 4, characterized in that: The clutch mechanism (23) includes an electric push rod (27) and a sliding frame (28), wherein the electric push rod (27) is installed inside the core barrel (2), a sliding groove (29) is provided on the core barrel (2), and the sliding frame (28) is fixedly connected to the output end of the electric push rod (27). The sliding frame (28) is slidably connected to the core barrel (2) through the sliding groove (29), and the bottom of the dual-axis stepping motor (21) is fixedly connected to one end of the sliding frame (28) away from the electric push rod (27).

7. The coil-wound heat exchanger for saturated alkane phase change operation according to claim 5, characterized in that: The cleaning assembly (24) includes a brush wall plate (30), an L-shaped frame (31), a rotating gear ring (32) and a power gear (33). The brush wall plate (30) is fixedly connected to the outer side of the rotating gear ring (32) through the L-shaped frame (31). The rotating gear ring (32) is rotatably connected to the outer side of the core barrel (2) through a bearing. One side of the brush wall plate (30) is in contact with the inner and outer walls of the multi-layer heat exchange tube (3). The power gear (33) is meshed with the rotating gear ring (32). The external spline (26) is fixed in the middle hole of the power gear (33). The outer side of the external spline (26) is rotatably connected to a second limit plate (34). The second limit plate (34) is fixed on the outer side wall of the core barrel (2).

8. The coil-wound heat exchanger for saturated alkane phase change operation according to claim 7, characterized in that: The wall brush plates (30) and the L-shaped frames (31) are each provided with four groups, and the four groups of wall brush plates (30) and the L-shaped frames (31) are distributed in a ring array.

9. The coil-wound heat exchanger for saturated alkane phase change operation according to claim 1, characterized in that: The wall expansion tube (4) is made of a tensile-resistant and high-temperature-resistant elastic rubber material, and welding heads are integrally fixed to both ends of the wall expansion tube (4) via sealing rings.

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