Heat pipe evaporation section, gravity heat pipe for exploiting hot dry rock geothermal and construction method

Abstract

The application discloses a heat pipe evaporation section, a gravity heat pipe for exploiting dry hot rock geothermal energy and a construction method. The heat pipe evaporation section comprises a heat conduction blind pipe, a plurality of end extension heat conduction rings are connected to the outer circumferential surface of the blind pipe body of the heat conduction blind pipe, the end extension heat conduction ring comprises a heat conduction ring body, one end of the heat conduction ring body is divided into a plurality of extension pieces by a cutting seam, the end of the extension piece is connected with a binding piece, after the binding piece is removed, the end of the extension piece can be radially unfolded, the lower surface of the binding piece is provided with a breaking pull rope, the breaking pull rope passes through the end extension heat conduction ring and the upper surface of the blind pipe body and extends to the open end of the blind pipe body, the closed end of the blind pipe body is sleeved with an end cap, and one end of the end cap is clamped with the extension piece of the end extension heat conduction ring close to the closed end of the heat conduction blind pipe. The application has the advantages of simple structure and higher efficiency for exploiting dry hot rock geothermal energy.

Description

Technical Field

[0001] This invention relates to the field of geothermal energy development and utilization technology, specifically to a heat pipe evaporation section, a gravity heat pipe for extracting dry hot rock geothermal energy, and a construction method thereof. Background Technology

[0002] Currently, most geothermal energy harvesting systems employ gravity heat pipes, which are heat exchange elements that achieve efficient heat transfer through the cyclic flow of a working fluid undergoing phase change. The liquid working fluid absorbs geothermal energy from the underground in the evaporation section of the gravity heat pipe, then evaporates, carrying away heat. The vaporized working fluid then flows from the pipe to the condensation section, where it condenses into a liquid, releasing latent heat. Under gravity, the liquid working fluid flows back to the evaporation section (the liquid working fluid adheres to the pipe as a condensate film), forming a closed loop. This process transfers a large amount of heat (geothermal energy) from the heating section to the condensation section of the gravity heat pipe.

[0003] To avoid the boiling limit problem in the evaporation section of a heat pipe, prevent the accumulation and thickening of the temperature boundary layer in the artificial heat storage, and improve the temperature uniformity of the evaporation section of the heat pipe to achieve a higher heat recovery rate, invention patent application number CN202011517061.7 discloses an underground heat exchange system and construction method for exploiting geothermal energy from dry hot rock using a gravity heat pipe. The heat exchange system includes an artificial heat storage, a gravity heat harvesting device, and a heat exchange device. The artificial heat storage is placed underground to absorb and store heat from the underground rock. The gravity heat harvesting device includes a gravity heat pipe extending from the underground artificial heat storage to the surface. A heat exchange fluid medium flows within the gravity heat pipe. The heat exchange device is used to transfer heat from the gravity heat harvesting device. The heat exchange device includes a hot water pipe wound around the outside of the condensation section. Water in the hot water pipe absorbs heat from the heat exchange fluid medium in the condensation section. This heat exchange system uses the gravity of the fluid itself to achieve circulating heat absorption and release, and then transmits the heat upwards, allowing heat from thousands of meters underground to be utilized on the surface.

[0004] While existing technologies using heat pipes with large-arc horizontal evaporation sections avoid the boiling limit problem of heat pipe evaporation sections and reduce the vertical temperature difference, improve temperature uniformity, and increase heat transfer efficiency and heat transfer capacity, the heat pipe evaporation section generally needs to pass through the vertical and arc sections of the wellbore during the installation process of the horizontal section of the geothermal well. This limits the length and outer diameter of the heat pipe evaporation section that can be easily installed in the horizontal section of the wellbore. In other words, the smaller the outer diameter of the heat pipe evaporation section, the easier it is to install a longer heat pipe evaporation section in the horizontal section of the wellbore. However, the smaller the outer diameter of the heat pipe evaporation section, the lower it will be in the artificial heat reservoir within the horizontal section of the geothermal wellbore. As heat extraction progresses, the temperature boundary layer of the artificial heat reservoir will accumulate and thicken, making it difficult for the heat pipe evaporation section to efficiently conduct and extract the heat energy from the upper high-temperature artificial heat reservoir. While increasing the diameter of the heat pipe evaporator section can solve the above problems, it will significantly affect the length of the heat pipe evaporator section that can be installed into the horizontal section of the geothermal well, thereby reducing the heat transfer area of ​​the heat pipe and affecting the efficiency of geothermal energy extraction. Summary of the Invention

[0005] The present invention aims to provide a heat pipe evaporation section with higher efficiency in mining hot dry rock geothermal energy.

[0006] Another object of the present invention includes providing a gravity heat pipe for exploiting hot dry rock geothermal energy, comprising the above-mentioned heat pipe evaporation section;

[0007] The present invention also aims to provide a method for installing gravity heat pipes for extracting hot dry rock geothermal energy, which is used to realize the installation of gravity heat pipes for extracting hot dry rock geothermal energy in the well.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] This invention provides a heat pipe evaporation section, including a heat-conducting blind tube. Several end-spreading heat-conducting rings are connected to the outer peripheral surface of the blind tube body. Each end-spreading heat-conducting ring includes a heat-conducting ring body. One end of the heat-conducting ring body is divided into several spread pieces by a slit. The ends of the spread pieces are connected to binding members. After the binding members are removed, the ends of the spread pieces can be radially spread away from the axis of the heat-conducting ring body.

[0010] The binding element is provided with a snap-off rope at its bottom;

[0011] The snap-through rope passes through the end-spreading heat-conducting ring and the top of the blind tube body, and extends toward the open end of the blind tube body;

[0012] The closed end of the blind tube body is fitted with an end cap;

[0013] One end of the end cap is provided with a snap-fit ​​interface, which snaps into the extension piece of the end-extension heat-conducting ring near the closed end.

[0014] Preferably, the snapping rope includes a rope and a blade fixedly connected to the rope, with the blade's cutting edge facing the length direction of the rope.

[0015] Preferably, the pull rope is a steel wire rope.

[0016] Preferably, the binding member includes a hoop, the inner diameter of one end of the hoop is larger than the outer diameter of the heat-conducting ring body, and the inner diameter of the other end is smaller than the outer diameter of the heat-conducting ring body, but larger than the outer diameter of the blind tube body.

[0017] Preferably, the inner or outer surface of the hoop is provided with a pre-breaking groove, the length direction of which is parallel to the axis of the hoop, and the pre-breaking groove is a groove for the blade or the like on the snap rope to break the hoop.

[0018] Preferably, the heat-conducting blind tube has a convex ring near the opening end, and the convex edge is used to assist the connection between the heat-conducting blind tube and the heat pipe insulation section.

[0019] Preferably, the closed end of the heat-conducting blind tube is provided with an inner cavity for increasing the inner and outer surface area of ​​the heat-conducting blind tube and for thinning the working fluid between the inner walls of the heat-conducting blind tube.

[0020] Preferably, the end cap is basin-shaped and has two connected ends.

[0021] Preferably, the end cap is made of nylon plastic.

[0022] Preferably, the end-spreading heat-conducting ring is made of metallic copper.

[0023] The present invention also provides a gravity heat pipe for extracting geothermal energy from dry hot rock (hereinafter referred to as: gravity heat pipe), comprising a condensation section, several vertical insulation sections with sealed ends, several flexible insulation sections with sealed ends, and the aforementioned heat pipe evaporation section, wherein one end of the vertical insulation section and one end of the flexible insulation section are sealed and connected by a pipe joint.

[0024] The lower end of the condensation section is sealed and connected to the upper end of the vertical insulation section through a pipe joint;

[0025] The end of the heat pipe evaporation section is sealed and connected to the lower end of the flexible insulation section.

[0026] Preferably, the pipe fitting includes a clamping ring and bolts, wherein the clamping ring is a circular plate with a plurality of bolt holes arrayed on its surface.

[0027] Preferably, the condensation section includes a bottom hole blind pipe, a concave ring, and a core tube. A working fluid return pipe is sealed to the convex surface of the concave ring, the concave surface of the concave ring faces the bottom hole blind pipe, and the outer edge of the concave ring is sealed to the opening of the bottom hole blind pipe. The upper end wall of the core tube is sealed to the central hole of the concave ring, and the lower end wall is sealed to a cementing plate. The cementing plate has a hole communicating with the core tube. The cementing plate is used to fix the wellhead and seal the upper end of the vertical insulation section.

[0028] Preferably, the cementing plate is provided with holes for threading the pull rope.

[0029] Preferably, the other end of the working fluid return pipe is connected to the flexible insulation section.

[0030] Preferably, the flexible insulation section is provided with embedded supporting ribs and tensile ribs.

[0031] Preferably, the supporting rib is a metal ring arranged radially inside the bendable insulation section.

[0032] Preferably, the tensile reinforcement is a bundle of steel wires arranged axially along the interior of the bendable insulation section.

[0033] Preferably, at least one end of the bendable insulation section is provided with a mating flange for assisting the connection between bendable insulation pipes.

[0034] Preferably, the body of the bendable insulation section is made of silicone rubber.

[0035] Preferably, the vertical insulation section is covered with a thermal insulation layer.

[0036] Preferably, the gravity heat pipe for mining dry hot rock geothermal energy is used in the mining of medium- and low-temperature dry hot rock geothermal energy.

[0037] The present invention also provides a method for installing the above-mentioned gravity heat pipe for extracting geothermal energy from dry hot rock, comprising the following steps:

[0038] 1) Installation personnel, equipment, and gravity heat pipe components enter the site;

[0039] 2) Ground connection of gravity heat pipe: According to the lifting requirements of the lifting equipment, as well as the length and weight data of the heat pipe evaporation section and a single flexible insulation section, on the ground near the wellhead, first seal and connect one end of the heat pipe evaporation section and the working fluid return pipe respectively, and then connect the other end of the flexible insulation section with an appropriate number of other flexible insulation sections.

[0040] 3) Lifting: Connect a lifting device to the pipe joint away from the heat pipe evaporation section and lift it. Lower the gravity heat pipe component that has been connected on the ground into the wellbore until the uppermost pipe joint is close to the wellbore opening. Then, connect the next flexible insulation section through the pipe joint on the mating protrusion of the uppermost flexible insulation section. After the connection is completed, connect another lifting device to the newly installed pipe joint and lift it to the previously connected lifting device so that it can be unloaded from the pipe joint connected to it. Then, lower the newly connected lifting device to the newly installed pipe joint near the wellbore opening. During the process of gradually lowering the connected gravity heat pipe components, lower the working fluid return pipe and the breakage rope at the same time. Repeat the above operation to realize the well lifting of the gravity heat pipe provided by the present invention.

[0041] 4) After the cementing plate is unfolded and fixed to the wellhead, the breakage rope is pulled from the hole on the cementing plate to the wellhead using a winch. Then, a valve is installed on the hole from which the breakage rope is pulled out, or a pipe fitting with a valve is connected to facilitate the addition of artificial thermal storage such as carbon dioxide.

[0042] 5) Installation of the heat exchanger: After the cementing plate of the gravity heat pipe provided by the present invention is installed in place, the heat exchanger is connected to the condenser section of the gravity heat pipe provided by the present invention.

[0043] Due to the adoption of the above technical solutions, the advantages of this invention are as follows:

[0044] 1. This invention increases the length of the heat pipe evaporation section extending into the horizontal wellbore, the heat conduction area, and the height of the heat pipe evaporation section's axis by setting an end-extended heat conduction ring in the heat pipe evaporation section. In addition, an inner cavity is provided at the closed end of the heat conduction blind tube, which increases the heat conduction area of ​​the heat conduction blind tube and the heating area of ​​the working fluid. These multiple mechanisms ensure the high efficiency of hot dry rock geothermal extraction.

[0045] 2. The working fluid reflux pipe provided by the present invention separates the condensed working fluid from the high-temperature vaporized working fluid for circulation, which greatly reduces the problems of liquid accumulation and gas-liquid entrainment in the gravity heat pipe, and realizes that the gravity heat pipe of the present invention has better heat conduction performance.

[0046] 3. The present invention uses a concave ring connected at the lower end of the condensation section, which includes a separately set working fluid return pipe and a core pipe. This not only realizes the separation and circulation of the working fluid, but also greatly simplifies the structure of the entire heating system and reduces the number of heat loss links.

[0047] 4. The gravity heat pipe structure provided by the present invention is simple, and the included flexible insulating section makes it easy to install the gravity heat pipe in a well that includes a horizontal section and / or an arc section. Attached Figure Description

[0048] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 A top view schematic diagram of Embodiment 1 of the heat pipe evaporation section provided by the present invention;

[0050] Figure 2 for Figure 1 A top view of the heat-conducting blind tube in the middle;

[0051] Figure 3 for Figure 1 A top view of the extended heat-conducting ring connected to the heat-conducting blind tube in the case when it is in the extended (split) state;

[0052] Figure 4 A side view of the end of the heat-conducting ring after it is connected to the binding piece;

[0053] Figure 5 To be Figure 4 After removing the binding parts, Figure 4 Right view schematic diagram of the end-extension heat conduction ring in the middle;

[0054] Figure 6 for Figure 1 A left-side view of the strapping components;

[0055] Figure 7 for Figure 1 A three-dimensional structural diagram of the end cap;

[0056] Figure 8 A top view schematic diagram of Embodiment 2 of the heat pipe evaporation section provided by the present invention;

[0057] Figure 9 for Figure 8 A top view of the heat-conducting blind tube in the middle;

[0058] Figure 10 for Figure 8 A top view of the extended heat-conducting ring connected to the heat-conducting blind tube in the case when it is in the extended (split) state;

[0059] Figure 11 This is a front view schematic diagram of a gravity heat pipe for extracting geothermal energy from dry hot rock, provided in an embodiment of the present invention.

[0060] Figure 12 for Figure 11A schematic diagram of the connection structure between the flexible insulation sections, between the flexible insulation section and the working fluid return pipe, and between the lowest flexible insulation section and the heat pipe evaporation section.

[0061] Figure 13 for Figure 12 A schematic axial cross-sectional view of the connection between the flexible insulation sections in the middle;

[0062] Figure 14 for Figure 11 The diagram shows a front view of the gravity heat pipe just as it is lowered into the wellbore where the hot dry rock geothermal energy is to be extracted.

[0063] Figure 15 for Figure 14 A schematic diagram showing the state after the gravity heat pipe installation is completed.

[0064] In the diagram: 1. Pipe fitting; 2. Fastening ring; 3. Slit; 4. Reinforcing ring; 5. L-shaped fitting; 6. Bolt; 10. Heat pipe evaporator section; 11. Blind tube; 111. Blind tube body; 1111. Open end; 1112. Closed end; 112. Convex ring; 113. Recessed cavity; 12. End-spreading heat-conducting ring; 121. Heat-conducting ring body; 1211. Spreading plate; 13. Bundling component; 131. Hoop ring; 1311. Pre-cut groove; 14. End cap; 141. Clamping joint ; 15. Breaking rope; 151. Rope; 152. Blade; 20. Bendable insulation section; 21. Bendable tube body; 211. Butt joint flange; 22. Support rib; 30. Vertical insulation section; 40. Condensation section; 41. Bottom hole blind pipe; 42. Concave ring; 43. Core tube; 50. Working fluid return pipe; 60. Cementing plate; 100. Gravity heat pipe; 200. Surface; 300. Wellbore; 400. Artificial thermal reservoir; 500. Dry hot rock strata fissure; 600. Heat exchanger. Detailed Implementation

[0065] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," "outer," "left," "right," "front," and "rear" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed during use, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0066] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0067] The specific implementation method is described below:

[0068] Embodiment 1 of a heat pipe evaporation section provided by the present invention, see [link to embodiment]. Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 The device includes a heat-conducting blind tube 11. Nine copper-made end-spreading heat-conducting rings 12 are welded to the outer circumferential surface of the blind tube body 111 of the heat-conducting blind tube 11. Each end-spreading heat-conducting ring 12 includes a heat-conducting ring body 121. One end of the heat-conducting ring body 121 is divided into 14 spread pieces 1211 by a slit 3. The ends of the spread pieces 1211 are connected to a binding member 13. After the binding member 13 is removed, the ends of the spread pieces 1211 can be radially spread away from the axis of the heat-conducting ring body 121.

[0069] The binding member 13 includes a hoop 131, and a pre-break groove 1311 is provided on the outer side of the hoop 131. The length direction of the pre-break groove 1311 is parallel to the axis of the hoop 131. The inner diameter of one end of the hoop 131 is larger than the outer diameter of the heat-conducting ring body 121, and the inner diameter of the other end is smaller than the outer diameter of the heat-conducting ring body 121 and larger than the outer diameter of the blind tube body 111. A breakable pull rope 15 is provided below the hoop 131.

[0070] The snap-off pull rope 15 includes a pull rope 151 and a blade 152 fixedly connected to the pull rope 151. The blade 152 faces the length direction of the pull rope 151 and the pre-break groove 1311. The pull rope 151 is preferably a steel wire rope. The pull rope 151 passes through the end-spreading heat-conducting ring 12 and the top of the blind tube body 111, and extends towards the open end 1111 of the blind tube body 111.

[0071] A protruding ring 112 is provided on the blind tube body 111 near the opening end 1111;

[0072] The closed end 1112 of the blind tube body 111 is fitted with a nylon plastic bowl-shaped end cap 14 that is connected at both ends;

[0073] One end of the end cap 14 is provided with a card interface 141, which is engaged with the end of the expansion piece 1211 of the end expansion heat conduction ring 12 near the closed end 1112.

[0074] The present invention provides a second embodiment of a heat pipe evaporation section, which is based on the heat pipe evaporation section described in embodiment 1 above, by further providing an inner cavity 113 at the closed end 1112 of the heat-conducting blind tube 11. See [link to embodiment 1]. Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 .

[0075] This invention provides an embodiment of a gravity heat pipe for extracting geothermal energy from dry hot rock. See also: Figure 1 , Figure 11 , Figure 12 , Figure 13 It includes a condensation section 40, a vertical insulation section 30, a flexible insulation section 20 and a heat pipe evaporation section 10 as described in Embodiment 1 above. The body of the flexible insulation section 20 is made of silicone rubber material, and a support rib 22 made of metal ring is radially embedded inside the body of the flexible insulation section 20. The end of the flexible insulation section 20 is provided with a butt flange 211.

[0076] The condensation section 40 includes a bottom hole blind pipe 41, a concave ring 42, and a core tube 43. A working fluid return pipe 50 is sealed to the convex surface of the concave ring 42, with the concave surface of the concave ring 42 facing the bottom hole blind pipe 41, and the outer edge of the concave ring 42 is sealed to the opening of the bottom hole blind pipe 41. The upper end wall of the core tube 43 is sealed to the center hole of the concave ring 42, and the lower end wall is sealed to a cementing plate 60, which has a hole communicating with the core tube 43.

[0077] The other end of the working fluid return pipe 50 is connected to the mating flange 211 of the two flexible insulating sections 20 near the heat pipe evaporation section 10 via an L-shaped connector, and is tightened and sealed by a tightening ring 4 and a bolt 6.

[0078] The sealing connections between the flexible insulation sections 20, the sealing connections between the vertical insulation sections 30, the sealing connections between the vertical insulation section 30 and one end of the flexible insulation section 20, and the sealing connections between the upper end of the vertical insulation section 30 and the cementing plate 60 can be made using either the traditional method of using a clamping ring 4 and bolts 6 or other existing technologies.

[0079] The open end 1111 of the heat pipe evaporation section 10 is inserted into one end of the flexible insulation section 20 near it, and is fixed and sealed by a fastening ring 2. The structure of the fastening ring 2 is the same as that of the hoop 131 without the pre-cut groove 1311.

[0080] The installation and construction method of the gravity heat pipe 100 based on the above-described extraction of dry hot rock geothermal energy provided in this embodiment of the invention is described in [reference needed]. Figure 1 , Figure 11 , Figure 12 , Figure 13 , Figure 14 , Figure 15 This includes the following steps:

[0081] 1) Installation personnel, equipment, and components of gravity heat pipe 100 enter the site, wherein the equipment includes at least two lifting devices, or one lifting device with at least two lifting joints, and the equipment also includes at least one lifting platform or scaffold for personnel to climb and assemble, with a height not less than the length of one insulation section, and the personnel include at least one person to climb and assemble and one ground operator to connect the component to be lifted to the lifting joint;

[0082] 2) Ground connection of gravity heat pipe 100: According to the lifting requirements of the lifting equipment, as well as the length and weight data of heat pipe evaporation section 10 and single flexible insulation section 20, on the ground near the wellhead of well 300, first seal and connect one end of heat pipe evaporation section 10 and working fluid return pipe 50 respectively, and then connect an appropriate number of other flexible insulation sections 20 to the other end of the flexible insulation section 20.

[0083] 3) Lifting: Connect the pipe joint 1, which is far from the heat pipe evaporation section 10, to one of the lifting devices and lift it. Lower the gravity heat pipe 100 component that is already connected on the ground into the well 300 until the uppermost pipe joint 1 is close to the well 300 opening. Then, connect the next flexible insulation section 20 to the mating protrusion 211 of the uppermost flexible insulation section 20 through the pipe joint 1. After the connection is completed, connect the other lifting device to the newly installed pipe joint 1 and lift it to the previously connected lifting device so that it can be unloaded from the pipe joint 1 connected to it. Then lower the newly connected lifting device to the newly installed pipe joint 1 close to the well 300 opening. During the process of gradually lowering the connected gravity heat pipe components, the working fluid return pipe 50 and the snap-locking rope 15 are lowered simultaneously. Repeat the above operation to realize the well lifting of the gravity heat pipe 100 provided by the present invention.

[0084] 4) After unfolding the display panel 1211 and fixing the cementing plate 60 to the wellbore 300, use a winch to pull the breakage rope 15 from the hole on the cementing plate 60 to the wellbore 300. Then install a valve on the hole from which the breakage rope 15 is pulled out, or connect a pipe fitting with a valve, so as to facilitate the addition of artificial thermal storage such as carbon dioxide.

[0085] 5) Installation of heat exchanger 600: After the cementing plate 60 of gravity heat pipe 100 provided by the present invention is installed in place, the heat exchanger 600 is connected to the condensing section 40 of gravity heat pipe 100 provided by the present invention.

[0086] The principle behind the gravity heat pipe 100 provided by this invention for improving the efficiency of geothermal extraction from dry hot rock is as follows:

[0087] First, by using the binding member 13 to gather the extended heat-conducting ring 12 on the heat pipe evaporation section 10, the outer diameter of the heat pipe evaporation section 10 can be reduced. This allows the arc section of the well 300 to pass through a longer heat pipe evaporation section, and the horizontal section of the well 300 to insert a longer heat pipe evaporation section 10.

[0088] Secondly, by inserting the longer heat pipe evaporation section 10 into the horizontal section of the well 300, and finally by pulling the pull rope 151, the blade 152 on the pull rope 151 cuts off the binding member 13 outside the spread piece 1211. The end of the spread piece 1211 is freed from the constraint of the binding member 13 and spreads out radially, filling the horizontal section of the well 300, thereby increasing the heat transfer area of ​​the heat pipe evaporation section 10.

[0089] Furthermore, the unfolded display panel 1211 will raise the axis of the heat pipe evaporation section 10, thus approaching the higher-temperature artificial heat storage 400 at a higher level.

[0090] Therefore, since the closed end 1112 of the heat-conducting blind tube 11 is provided with an inner cavity 113 for increasing the inner and outer areas of the heat-conducting blind tube 11 and thinning the working fluid between the inner walls of the heat-conducting blind tube 11, the heat-conducting area and the heated area of ​​the working fluid are improved.

[0091] Finally, since the working fluid return pipe 50 separates the condensed working fluid from the high-temperature vaporized working fluid for circulation, the problem of liquid accumulation and gas-liquid entrainment in the gravity heat pipe 100 is greatly reduced, and the gravity heat pipe 100 of the present invention has better heat conduction performance.

[0092] The above embodiments of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is impossible to exhaustively list all possible implementations here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A heat pipe evaporation section (10), comprising a heat-conducting blind tube (11), characterized in that: The heat-conducting blind tube (11) has several end-spreading heat-conducting rings (12) connected to the outer circumferential surface of the blind tube body (111). The end-spreading heat-conducting ring (12) includes a heat-conducting ring body (121). One end of the heat-conducting ring body (121) is divided into several spread pieces (1211) by a slit (3). The ends of the spread pieces (1211) are connected to a binding member (13). After the binding member (13) is removed, the ends of the spread pieces (1211) can be spread radially away from the axis of the heat-conducting ring body (121). The binding member (13) is provided with a snap-off rope (15) underneath; The snap-off pull rope (15) passes through the end-spreading heat-conducting ring (12) and the top of the blind tube body (111), and extends toward the open end (1111) of the blind tube body (111). The closed end (1112) of the blind tube body (111) is fitted with an end cap (14). One end of the end cap (14) is provided with a card interface (141), which is engaged with the expansion piece (1211) of the end expansion heat conduction ring (12) near the closed end (1112); The binding member (13) includes a hoop (131), the inner diameter of one end of the hoop (131) is larger than the outer diameter of the heat-conducting ring body (121), and the inner diameter of the other end is smaller than the outer diameter of the heat-conducting ring body (121) and larger than the outer diameter of the blind tube body (111). The inner or outer surface of the hoop (131) is provided with a pre-cut groove (1311), and the length direction of the pre-cut groove (1311) is parallel to the axis of the hoop (131). The breakable pull rope (15) includes a pull rope (151) and a blade (152) fixedly connected to the pull rope (151), with the blade (152) facing the length direction of the pull rope (151) and the pre-break groove (1311).

2. The heat pipe evaporation section (10) as described in claim 1, characterized in that: The heat-conducting blind tube (11) has a protruding ring (112) near the opening end (1111).

3. The heat pipe evaporation section (10) as described in claim 1, characterized in that: The closed end (1112) of the heat-conducting blind tube (11) is provided with an inner cavity (113).

4. A gravity heat pipe (100) for extracting geothermal energy from dry hot rock, characterized in that: It includes a condensing section (40), a plurality of vertically insulating sections (30) with sealed ends, a plurality of flexible insulating sections (20) with sealed ends, and a heat pipe evaporation section (10) as described in any one of claims 1 to 3, wherein one end of the vertically insulating section (30) is sealed to one end of the flexible insulating section (20). The lower end of the condensation section (40) is sealed and connected to the upper end of the vertical insulation section (30); The open end (1111) of the heat pipe evaporation section (10) is sealed and connected to the lower end of the flexible insulation section (20).

5. The gravity heat pipe (100) for extracting geothermal energy from dry hot rock as described in claim 4, characterized in that: The condensation section (40) includes a bottom hole blind pipe (41), a concave ring (42), and a core pipe (43). A working fluid return pipe (50) is sealed on the convex surface of the concave ring (42). The concave surface of the concave ring (42) faces the bottom hole blind pipe (41), and the outer edge of the concave ring (42) is sealed to the opening of the bottom hole blind pipe (41). The upper end wall of the core pipe (43) is sealed to the center hole of the concave ring (42), and the lower end wall is sealed to a cementing plate (60). The cementing plate (60) has a hole communicating with the core pipe (43).

6. The gravity heat pipe (100) for extracting geothermal energy from dry hot rock as described in claim 4, characterized in that: The flexible insulation section (20) is provided with embedded support bars (22) and tensile bars.

7. The gravity heat pipe (100) for extracting geothermal energy from dry hot rock as described in claim 4, characterized in that: The vertical insulation section (30) is covered with an insulation layer.

8. A method for installing a gravity heat pipe (100) for extracting geothermal energy from dry hot rock, characterized in that: The gravity heat pipe (100) for extracting geothermal energy from dry hot rock as described in claim 5 includes the following steps: 1) Installation personnel, equipment, and components of the gravity heat pipe (100) arrive on site; 2) Ground connection of gravity heat pipe (100): According to the lifting requirements of the lifting equipment, as well as the length and weight data of the heat pipe evaporation section (10) and a single flexible insulation section (20), on the ground near the wellhead (300), first seal one flexible insulation section (20) to one end of the heat pipe evaporation section (10) and the working fluid return pipe (50), and then connect an appropriate number of other flexible insulation sections (20) to the other end of the flexible insulation section (20). 3) Lifting: Connect the pipe joint (1) away from the heat pipe evaporation section (10) with one of the lifting equipment and lift it. Sink the gravity heat pipe (100) components that have been connected on the ground into the well (300) until the uppermost pipe joint (1) is close to the well (300) opening. Then connect the next bendable insulation section (20) through the pipe joint (1) on the mating protrusion (211) of the uppermost bendable insulation section (20). After the connection is completed, connect the other lifting part to the newly installed pipe joint (1) and lift it to the previously connected lifting part. It can be unloaded from the pipe joint (1) connected to it. Then lower the newly connected lifting part to the newly installed pipe joint (1) close to the well (300) opening. During the process of gradually lowering the connected gravity heat pipe components, the working fluid return pipe (50) and the snap-off rope (15) are lowered simultaneously. The gravity heat pipe (100) can be lifted into the well by following the above operation. 4) Unfold the display panel (1211), and after the cementing plate (60) is fixedly connected and positioned at the opening of the well passage (300), use a winch to pull the breakage rope (15) out of the well passage (300) through the hole on the cementing plate (60). Then install a valve on the hole where the breakage rope (15) is pulled out, or connect a pipe fitting with a valve, so as to facilitate the addition of artificial thermal storage such as carbon dioxide. 5) Installation of heat exchanger (600): After the cementing plate (60) of gravity heat pipe (100) is installed in place, connect heat exchanger (600) to condenser section (40) of gravity heat pipe (100).

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