Circulating mechanism for geothermal well

Abstract

The utility model provides a circulating mechanism for a geothermal well, which comprises a ground device and a heat exchanger, and the ground device comprises a circulating water inlet pipe and a circulating water return pipe which extend into the geothermal well and are respectively used as a water inlet end and a water return end of external water equipment; the heat exchanger is arranged in the geothermal well and is provided with a circulating side and a heat exchange side, the heat exchange side is communicated with an external geothermal environment, the circulating water inlet pipe and the circulating water return pipe are communicated with the circulating side, a bent pipe is arranged between the circulating water return pipe and the heat exchanger, and an included angle is formed between the extending direction of the bent pipe and the flowing direction of circulating water so as to slow down the flowing speed of the circulating water entering the heat exchanger.

Description

TECHNICAL FIELD

[0001] At least one embodiment of the present application relates to the technical field of geothermal energy conversion, and more particularly to a circulating mechanism for geothermal well. BACKGROUND

[0002] As a clean and renewable energy, geothermal energy has been widely used in heating, power generation, hot spring utilization, agricultural greenhouse and other fields. The main exploitation method of geothermal energy is to extract geothermal water through geothermal well and exchange heat with external circulating water.

[0003] With the emphasis on the recycling of geothermal energy and the increasing awareness of underground environment protection, it is particularly important to prevent environmental problems such as ground subsidence and water depletion caused by excessive extraction of underground water. Therefore, higher requirements are put forward for the recharge amount of geothermal well. For example, the geothermal tail water of geothermal well must reach more than 95% of the same layer recharge amount, and even in the ideal state, the recharge amount should be equal to or slightly greater than the extraction amount to achieve equal recharge.

[0004] Therefore, how to provide a circulating mechanism for geothermal well which can improve the recharge amount of geothermal water while ensuring the heat exchange efficiency between external circulating water and geothermal water has become a problem to be solved in the current geothermal energy technical field. SUMMARY

[0005] Therefore, in order to solve the above and other technical problems in the prior art, the present application provides a circulating mechanism for geothermal well to improve the recharge amount and heat exchange efficiency of geothermal water.

[0006] The present application provides a circulating mechanism for geothermal well, comprising an above-well device, comprising: a circulating water inlet pipe and a circulating water return pipe extending into a geothermal well and used as a water inlet end and a water return end of an external water-using equipment respectively; a heat exchanger arranged in the geothermal well and having a circulating side and a heat exchange side, the heat exchange side being in communication with an external geothermal environment, the circulating water inlet pipe and the circulating water return pipe being in communication with the circulating side, and a bend pipe being arranged between the circulating water return pipe and the heat exchanger, the extension direction of the bend pipe forming an angle with the flow direction of the circulating water to slow down the flow rate of the circulating water entering the heat exchanger.

[0007] According to the embodiment of the present application, the bend pipe is configured to extend along the horizontal direction.

[0008] According to the embodiment of the present application, the above-well device comprises: a well platform arranged at the wellhead of the geothermal well; a circulating adapter cover arranged on the well platform, the upper ends of the circulating water inlet pipe and the circulating water return pipe being arranged on the circulating adapter; and an elbow arranged on the circulating adapter and configured to communicate the circulating water inlet pipe or the circulating water return pipe with the water-using equipment.

[0009] According to the embodiment of the utility model, the well device further comprises: a cover body, which is arranged on the well mouth and covers the circulating connector plate and the elbow; and a cover plate, which is arranged on the cover body in an openable and closable manner; wherein a lock is further arranged between the cover plate and the cover body.

[0010] According to the embodiment of the utility model, the heat exchanger further comprises: an inner tube, which is arranged in a vertical direction; a heat exchange tube group, which comprises a plurality of heat exchange tubes and is arranged on the inner tube, a shell side of the heat exchange tube group and the inner tube forms the heat exchange side, and a tube side in the heat exchange tube forms the circulation side; a partition plate, which extends along the axial direction of the inner tube and has a water passage at the upper portion to divide the heat exchange side into a first portion and a second portion which are in communication with each other; wherein the circulating water flowing through the circulation side and the geothermal water flowing through the heat exchange side are configured to flow in opposite directions to form counter-flow heat exchange.

[0011] According to the embodiment of the utility model, the heat exchanger further comprises: a first connector, which is arranged at the upper portion of the inner tube and has a circulating water inlet connected with the circulating water inlet pipe and a circulating water outlet connected with the circulating water outlet pipe, the circulating water inlet and the circulating water outlet are located on both sides of the partition plate to be isolated; and a second connector, which is arranged at the lower portion of the inner tube and has a heat exchange water inlet connected with the first portion and a heat exchange water outlet connected with the second portion.

[0012] According to the embodiment of the utility model, the heat exchanger further comprises: a plurality of heat exchange water outlets, and the sum of the cross-sectional areas of each heat exchange water outlet is 90% to 100% of the cross-sectional area of the heat exchange water inlet.

[0013] According to the embodiment of the utility model, the heat exchanger further comprises: a heat exchange water inlet pipe, which is connected with the heat exchange water inlet and coaxially arranged with the second connector.

[0014] According to the embodiment of the utility model, the heat exchange water inlet pipe comprises a first end located in the heat exchange side and a second end located outside the heat exchange side; wherein the first end is provided with a water baffle cover to connect the heat exchange water inlet pipe with the first portion and isolate the second portion.

[0015] According to the embodiment of the utility model, the heat exchanger further comprises: an outer tube, which is arranged outside the inner tube, and a heat preservation material is arranged between the inner tube and the outer tube.

[0016] According to the embodiment of the present application, the flow rate of circulating water is effectively reduced by installing the elbow between the circulating backwater pipe and the heat exchanger, and the heat exchange time of water flow in the heat exchanger is prolonged. The circulating water can be more fully heat-exchanged with the heat exchanger, and the heat energy conversion efficiency is improved. At the same time, the extracted geothermal water is heat-exchanged with the circulating water by the method of directly heat-exchanging in the geothermal well, and the equal recharging of geothermal water is effectively realized. The process of the circulating system is simplified, and the sustainable utilization of geothermal resources is ensured. Since the extracted geothermal water can be directly recharged to the original heat reservoir after completing the heat exchange, the additional conveying and recharging facilities are saved, and the operation efficiency and economic benefit of the circulating mechanism are further improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above and other objects, features and advantages of the present application will become more apparent from the following description of the preferred embodiments of the present application with reference to the accompanying drawings, in which:

[0018] Figure 1 A schematic diagram of a circulating mechanism for a geothermal well according to an embodiment of the present application is schematically shown, and the proportional relationship of each part in the vertical direction is modified in the figure;

[0019] Figure 2 is a perspective view of the wellhead device of the schematic embodiment shown; Figure 1

[0020] Figure 3 A perspective view of a heat exchanger omitting an outer pipe according to an embodiment of the present application is schematically shown;

[0021] Figure 4 is a perspective view of the heat exchanger of the schematic embodiment shown, omitting the first joint and the inner pipe; Figure 3

[0022] Figure 5 is a perspective view of the heat exchanger of the schematic embodiment shown, omitting the heat exchange joint plate; and Figure 4

[0023] is a perspective view of the lower part of the heat exchanger of the schematic embodiment shown, omitting the inner pipe. Figure 6 Figure 1

[0024] In the drawings, the meanings of the reference signs are as follows:

[0025] 1, wellhead device;

[0026] 11, circulating water inlet pipe;

[0027] 12, circulating backwater pipe;

[0028] 13, elbow;

[0029] 14, circulating joint plate;​​​​

[0030] 15. elbow;

[0031] 16. cover body;

[0032] 17. cover plate;

[0033] 18. lock;

[0034] 19. well stand;

[0035] 191. connecting ring;

[0036] 2. heat exchanger;

[0037] 21. inner tube;

[0038] 211. first part;

[0039] 212. second part;

[0040] 22. heat exchange tube group;

[0041] 221. heat exchange joint plate;

[0042] 23. partition plate;

[0043] 231. water pass-through;

[0044] 24. first joint;

[0045] 241. circulating water inlet;

[0046] 242. circulating water return;

[0047] 243. exhaust pipe;

[0048] 25. second joint;

[0049] 251. heat exchange water inlet;

[0050] 252. heat exchange water return;

[0051] 26. heat exchange water inlet pipe;

[0052] 261. water blocking cover;

[0053] 27. outer tube;

[0054] 28. rib plate;

[0055] 3. temperature measuring unit; and

[0056] 4. flow sensing unit. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical scheme and advantages of the utility model clearer and more comprehensible, the following will make further detailed description of the utility model in combination with specific embodiments and with reference to the drawings.

[0058] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. As used herein, the terms "comprises", "comprising", "includes", "including" and the like are, unless otherwise stated, taken to mean that the stated features, steps, operations and / or components are present and can be present in the described combinations and / or permutations, but not excluding the presence or addition of one or more other features, steps, operations, components or groups thereof.

[0059] All terms used herein, including technical and scientific terms, have the meaning commonly understood by one of ordinary skill in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning that is consistent with the context of the specification, and should not be interpreted in an idealized or overly formal way.

[0060] In the case of using expressions such as "at least one of A, B, and C", etc., it generally should be interpreted to include any of the possibilities of A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc. In the case of using expressions such as "at least one of A, B, or C", etc., it generally should be interpreted to include any of the possibilities of A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.

[0061] It should also be noted that the directional phrases mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only with reference to the drawings, and are not intended to limit the protection scope of the utility model. Throughout the drawings, the same elements are represented by the same or similar reference numerals. When it may cause confusion in understanding the utility model, the conventional structure or configuration will be omitted.

[0062] The conventional geothermal well generally includes a pumping well and a recharge well. The pumping well is suitable for pumping geothermal water to exchange heat with an external water environment on the well, and the recharge well is used for re-injecting the low-temperature geothermal water after heat exchange into the ground. In order to reduce the land occupation area of the geothermal well, some geothermal wells are configured as a single-well structure, integrating the pumping well and the recharge well in one wellhead.

[0063] And, with the emphasis on the recycling of geothermal energy and the awareness of the protection of the underground environment, it is particularly important to prevent environmental problems such as land subsidence and water depletion caused by over-extraction of groundwater. Therefore, higher requirements are put forward for the recharge amount of geothermal wells. For example, the geothermal tail water of the geothermal well must be recharged to the same layer in an amount of more than 95%, and even in an ideal state, the recharge amount should be equal to or slightly greater than the extraction amount to achieve equal recharge.

[0064] Therefore, how to provide a circulating mechanism for geothermal wells that can improve the recharge amount of geothermal water while ensuring the heat exchange efficiency of external circulating water and geothermal water has become a problem to be solved in the current geothermal energy technology field.

[0065] Figure 1 The schematic diagram of the circulating mechanism for geothermal wells according to the embodiment of the present application is shown schematically, and the proportional relationship of each part in the vertical direction is modified.

[0066] The embodiment of the present application provides a circulating mechanism for geothermal wells, as shown in the figure, which comprises an on-well device 1 and a heat exchanger 2. Figure 1 The on-well device 1 comprises a circulating water inlet pipe 11 and a circulating water return pipe 12, which extend into the geothermal well and are used as the water inlet end and the water return end of the external water-using equipment respectively; the heat exchanger 2 is arranged in the geothermal well and has a circulating side and a heat exchange side, the heat exchange side is in communication with the external geothermal environment, the circulating water inlet pipe 11 and the circulating water return pipe 12 are in communication with the circulating side, and a bend pipe 13 is arranged between the circulating water return pipe 12 and the heat exchanger 2, the extension direction of the bend pipe 13 forms an angle with the flow direction of the circulating water to slow down the flow rate of the circulating water entering the heat exchanger 2.

[0067] According to the above arrangement, by arranging the bend pipe 13 between the circulating water return pipe 12 and the heat exchanger 2, and the extension direction of the bend pipe 13 forms an angle with the flow direction of the circulating water, the flow rate of the circulating water entering the heat exchanger 2 is effectively slowed down, thereby prolonging the heat exchange time of the circulating water in the heat exchanger 2, improving the heat energy conversion efficiency, and ensuring that the circulating water can fully absorb the heat in the geothermal environment; at the same time, it helps to reduce the impact of water flow on the internal structure of the heat exchanger 2, prolonging the service life of the circulating mechanism.

[0068] Further, by directly exchanging heat in the geothermal well, the extracted geothermal water and the circulating water are exchanged, which effectively realizes the equal recharge of geothermal water. The process of the circulating system is simplified, and the sustainable use of geothermal resources is ensured. Since the extracted geothermal water can be directly recharged to the original heat reservoir after completing the heat exchange, additional transportation and recharge facilities are saved, further improving the operation efficiency and economic benefit of the circulating mechanism.

[0069] According to the embodiment of the utility model, the circulating mechanism for the geothermal well can be applied to various geothermal wells, specifically including: any one of a shallow geothermal well (the depth is about 200-500m), a middle geothermal well (the depth is about 500-1500m) and a deep geothermal well (the depth is usually about 1500m and above).

[0070] In addition, the circulating mechanism also needs to work with the submersible pump in the geothermal well. The submersible pump is located below the heat exchanger 2 and is responsible for pumping geothermal water and delivering it to the heat exchange side of the heat exchanger 2 to realize heat exchange with the circulating water on the circulating side. To ensure efficient use of geothermal energy and stable operation of the system.

[0071] In an illustrative embodiment, as shown in Figure 1 The elbow pipe 13 is configured to extend in the horizontal direction.

[0072] It should be noted that during the circulating water delivery process, the circulating water in the circulating backwater pipe 12 flows from the water using equipment on the ground to the heat exchanger 2 in the geothermal well for heat exchange. In the design process of the circulating system and the geothermal well, considering the economy and the feasibility of actual operation, the pipes in the circulating system and the geothermal well are arranged in the vertical direction. Therefore, the flow direction of the water in the circulating backwater pipe 12 can be considered as vertical flow. In the horizontally extending elbow pipe 13, the flow direction of the circulating water forms a 90-degree angle with the flow direction of the circulating water above and below the elbow pipe 13.

[0073] According to the above setting mode, the water flow in the circulating backwater pipe 12 undergoes two 90-degree flow direction changes before entering the heat exchanger 2 through the action of the elbow pipe 13, effectively slowing down the water flow speed and increasing the water flow residence time in the heat exchanger 2, thereby improving the heat exchange efficiency. In addition, this design ingeniously combines the vertical arrangement of the circulating system pipes and the geothermal well, which not only ensures the economy and feasibility of the system design, but also optimizes the water flow dynamics, reduces the impact of water flow on the pipes and the heat exchanger 2, and prolongs the service life of the equipment.

[0074] However, the embodiments of the utility model are not limited to this, the elbow pipe 13 can also extend in other directions, so that the flow direction of the circulating water flowing in the elbow pipe 13 forms an angle with the flow direction of the circulating water above and below the elbow pipe 13, so as to slow down the flow speed.

[0075] Figure 2 is Figure 1 The perspective view of the well device of the illustrative embodiment shown in

[0076] In an illustrative embodiment, as shown in Figure 2As shown, the wellhead device 1 comprises: a well platform 19 arranged at the wellhead of the geothermal well; a circulation adapter 14 arranged on the well platform 19, and the upper ends of the circulating water inlet pipe 11 and the circulating water return pipe 12 are arranged on the circulation adapter 14; and a bend 15 arranged on the circulation adapter 14 and configured to communicate the circulating water inlet pipe 11 or the circulating water return pipe 12 with the water using equipment.

[0077] In detail, the well platform 19 comprises but is not limited to a foundation arranged at the wellhead, and a platform structure built on the foundation, the platform structure is made of high-strength steel or concrete material, or a composite structure of both.

[0078] In an illustrative embodiment, as shown in Figure 2 The upper end of the well platform 19 is provided with a connecting ring 191 adapted to connect the circulation adapter 14, wherein the connecting ring 191 is connected to the circulation adapter 14 by bolts.

[0079] Further, the upper ends of the circulating water inlet pipe 11 and the circulating water return pipe 12 are connected to the bottom end of the circulation adapter 14 by flanges, and the circulation adapter 14 is further provided with two circulating water holes concentric with the circulating water inlet pipe 11 and the circulating water return pipe 12 for circulating water flow. In addition, the bend 15 is provided with two flanges sealed on the circulating water holes, forming a sealed circulating passage between the external water using equipment and the wellhead device, wherein the external water using equipment is connected to the flange of the bend 15.

[0080] In an illustrative embodiment, as shown in Figure 2 The wellhead device 1 further comprises: a cover body 15 covering the wellhead and shielding the circulation adapter 14 and the bend 15; and a cover plate 17 arranged on the cover body 15 in an openable and closable manner; wherein a lock 18 is further arranged between the cover plate 17 and the cover body 15.

[0081] According to the above arrangement, the cover body 15 and the openable and closable cover plate 17 are provided with the lock 18, which effectively protects the circulation adapter 14 and the bend 15, prevents external impurities and adverse weather conditions from damaging the key components, and ensures the stable operation and long-term reliability of the circulating system. At the same time, the openable and closable design of the cover plate 17 facilitates the daily maintenance and repair work, and the arrangement of the lock 18 increases the safety of the system, prevents unauthorized access and operation, and thus improves the safety and maintenance convenience of the overall system.

[0082] According to the embodiment of the present application, a plurality of fixing blocks are arranged in the cover body 15 in a circumferential direction, and the cover body 15 is installed on the circulation adapter 14 through the fixing blocks.

[0083] Figure 3 A perspective view of a heat exchanger without an outer pipe according to an embodiment of the present application is schematically shown.Figure 4 is Figure 3 a perspective view of the heat exchanger of the schematic embodiment shown in Figure 5 is Figure 4 a perspective view of the heat exchanger of the schematic embodiment shown in

[0084] In a schematic embodiment, as shown in Figure 3 and Figure 4 the heat exchanger 2 comprises: an inner tube 21 arranged in a vertical direction; a heat exchange tube group 22 comprising a plurality of heat exchange tubes arranged in the inner tube 21, the inner tube 21 and the heat exchange tube group 22 forming a heat exchange side in a shell side, and a tube side in a tube side; a partition plate 23 extending in the axial direction of the inner tube 21, and the upper part forming a water passage 231 to divide the heat exchange side into a first part 211 and a second part 212 connected in the upper part; wherein the circulating water flowing through the tube side and the geothermal water flowing through the heat exchange side are configured to flow in opposite directions to form counter-flow heat exchange.

[0085] In detail, in the heat exchange side, the geothermal water flows from bottom to top through the water passage 231 to the second part 212 from the first part 211, and then flows out of the second part 212 from top to bottom, wherein the length of the water passage 231 is configured to be less than or equal to the diameter of the inner tube 21, and the height should meet the demand of geothermal water flow.

[0086] According to the above arrangement, the heat exchange efficiency is significantly improved, because the counter-flow heat exchange mode makes the temperature difference between the circulating water and the geothermal water more fully utilized in the heat exchange process, thereby enhancing the heat transfer effect.

[0087] In a schematic embodiment, the heat exchange tube comprises but is not limited to being made of a material with good thermal conductivity, such as copper, etc.

[0088] Figure 6 is Figure 1 a perspective view of the lower part of the heat exchanger of the schematic embodiment shown in

[0089] In a schematic embodiment, as shown in Figure 3 to 6, the plurality of heat exchange tubes are configured as U-shaped tubes, and the embodiments of the present application are not limited thereto, both ends of the plurality of heat exchange tubes are mounted on a heat exchange plate 221 having a plurality of holes, wherein the heat exchange plate 221 is mounted on the upper part of the inner tube 21 through the partition plate 23, so that part of the tube segments of the plurality of heat exchange tubes are located in the first part 211, and the remaining tube segments are located in the second part 212.

[0090] In a schematic embodiment, as shown in Figure 4As shown, the plurality of heat exchange tubes are arranged in a row array and / or a column array through the heat exchange connecting plate 221 and are evenly spaced in the cross section of the inner tube 21. In detail, more heat exchange tubes can be arranged near the partition plate 23 due to the similar tube diameter with the inner tube 21, while fewer heat exchange tubes are arranged far from the partition plate 23. In addition, the heat exchange tubes far from the partition plate 23 are located outside the heat exchange tubes near the partition plate 23 at the turning part. The number of heat exchange tubes arranged in the inner tube 21 is maximized, the heat exchange effect between the heat exchange tubes and the geothermal water is increased, and thus the overall heat exchange efficiency is improved.

[0091] In an exemplary embodiment, as shown in Figure 3 and Figure 6 The heat exchanger 2 further comprises a first joint 24 arranged at the upper portion of the inner tube 21, having a circulating water inlet 241 communicating with the circulating water inlet pipe 11 and a circulating water outlet 242 communicating with the circulating water outlet pipe 12, and the circulating water inlet 241 and the circulating water outlet 242 are located on both sides of the partition plate 23 to be isolated; and a second joint 25 arranged at the lower portion of the inner tube 21, having a heat exchange water inlet 251 communicating with the first part 211 and a heat exchange water outlet 252 communicating with the second part 212.

[0092] According to the embodiment of the present application, the circulating water inlet pipe 11 and the circulating water outlet pipe 12 are connected to the first joint 24 through flanges.

[0093] In an exemplary embodiment, as shown in Figure 1 The flanges of the circulating water inlet pipe 11 and the circulating water outlet pipe 12 and the first joint 24 are further provided with an exhaust pipe 243, one end of the exhaust pipe 243 extends into the first part 211 or the second part 212, and the other end is led out from the flanges of the circulating water inlet pipe 11 and the circulating water outlet pipe 12 or the first joint 24, so as to guide at least part of the air in the heat exchange side to the outside, prevent the formation of an air layer in the heat exchange side, reduce the contact area of the geothermal water with the heat exchange tube group 22, and affect the heat exchange efficiency.

[0094] According to the embodiment of the present application, the circulating water inlet pipe 11 is communicated with the ports of the heat exchange tube group 22 located in the first part 211 through the circulating water inlet 241, and the circulating water outlet pipe 12 is communicated with the ports of the heat exchange tube group 22 located in the second part 212 through the circulating water outlet 242; and the first part 211 is communicated with the heat exchange water inlet 251, and the second part 212 is communicated with the heat exchange water outlet 252, so as to supply the heat exchange water to enter and exit. The flow path of the geothermal water in the heat exchange side is first upward, then downward after passing through the water passing port 231 on the partition plate 23, and then turns to downward flow. At the same time, the flow direction of the circulating water in the circulating side is first downward, then upward after passing through the turning part. This counter-flow design optimizes the heat exchange process and improves the heat energy conversion efficiency.

[0095] Further, the configuration of the partition plate 23 not only increases the heat exchange path length between the heat exchange tube and the geothermal water, but also realizes the counterflow heat exchange between the circulating water and the geothermal water, and significantly improves the heat exchange efficiency of the heat exchanger 2.

[0096] In an illustrative embodiment, as shown in Figure 6 The heat exchanger 2 further comprises a heat exchange water inlet pipe 26, which is in communication with the heat exchange water inlet 251 and coaxially arranged with the second joint 25.

[0097] According to the embodiment of the present application, the heat exchange water inlet 251 is concentrically arranged with the second joint 25, and the heat exchange water outlet 252 is arranged offset from the center line of the second joint 25 and within the range of the second part 212.

[0098] Further, the heat exchange water inlet pipe 26 comprises a first end on the heat exchange side and a second end outside the heat exchange side; wherein the first end is provided with a water baffle 261 to communicate the heat exchange water inlet pipe 26 with the first part 211 and isolate the second part 212.

[0099] According to the embodiment of the present application, as shown in Figure 6 The middle part of the second joint 25 is concentrically arranged with a circular heat exchange water inlet 251, and the first end of the heat exchange water inlet pipe 26 is located within the heat exchange water inlet 251 and extends below the heat exchange tube group 22. Further, the first end is provided with a water baffle 261, which is suitable for separating the inside of the heat exchange water inlet pipe 26 from the second part 212 and forming a port in communication with the first part 211.

[0100] In detail, the water baffle 261 includes but is not limited to a circular plate structure, and the water baffle 261 is arranged in the axial direction of the inner tube 21 and spaced from the heat exchange water inlet 251 to form a reversing flow channel in communication with the first part 211, so that the geothermal water flowing through the heat exchange water inlet 251 is blocked to the first part 211 and diffuses along the radial direction of the inner tube 21311; the other side of the water baffle 261 is connected with the partition plate 23 and the outer wall of the heat exchange water inlet pipe 26 and seals the second part 212, so that the downward backflow of the geothermal water through the second part 212 is blocked, and is discharged from the outside of the heat exchange water inlet pipe 26 through multiple second water outlets, so as to reduce the flow rate of the geothermal water on the heat exchange side, thereby achieving more sufficient heat exchange with the heat exchange tube group 22.

[0101] In an illustrative embodiment, as shown in Figure 6 Each heat exchange water outlet 252 has a cross-sectional area of 90% to 100% of the cross-sectional area of the heat exchange water inlet 251.

[0102] According to the above setting mode, a plurality of heat exchange return water inlets 252 with a total area approximately equal to that of the heat exchange water inlet 251 are arranged, and the dispersed return water inlet design effectively improves the structural strength of the second joint 25.

[0103] In an illustrative embodiment, as shown in Figure 1 The heat exchanger 2 further comprises an outer tube 27 sleeved outside the inner tube 21, and a heat preservation material is arranged between the inner tube 21 and the outer tube 27.

[0104] In detail, the outer tube 27 is coaxially arranged with the inner tube 21, and a plurality of rib plates 28 are arranged on the outer wall of the inner tube 21. Part of the rib plates 28 are distributed along the circumference of the outer wall of the inner tube 21 and extend along the axial direction, and the other part is distributed along the axial direction of the inner tube 21 and extends along the circumference, forming a meshed frame on the outer wall of the inner tube 21 to enhance the structural stability of the heat exchanger 2. In addition, the outer tube 27 covers the outside of the plurality of rib plates 28 and is spaced apart from the outer wall of the inner tube 21 to fill the heat preservation material, such as heat preservation cotton, so as to isolate the heat exchange between the pipe of the heat exchanger 2 and the external environment, reduce the energy loss of the geothermal water due to heat exchange with the external environment during the heat exchange process, and further improve the heat exchange efficiency of the heat exchanger 2.

[0105] In an illustrative embodiment, as shown in Figure 6 The temperature measuring assembly is suitable for collecting the inlet water temperature and / or return water temperature of the geothermal water.

[0106] According to the embodiment of the present application, the temperature measuring assembly comprises two temperature measuring units 3. One temperature measuring unit 3 is installed on the heat exchange water inlet pipe 26, and the monitoring end is located inside the heat exchange water inlet pipe 26, which is suitable for monitoring the inlet water temperature of the geothermal water in the heat exchange water inlet pipe 26. The other temperature measuring unit 3 is installed on the second joint 25, and the monitoring end is located inside the second part 212, which is suitable for monitoring the return water temperature of the geothermal water in the second part 212.

[0107] In detail, the temperature measuring unit 3 includes but is not limited to a temperature transmitter.

[0108] In an illustrative embodiment, as shown in Figure 6 The flow assembly is suitable for collecting the inlet flow and / or return flow of the geothermal water.

[0109] According to the embodiment of the present application, the flow assembly includes but is not limited to two flow sensing units 4. In detail, the sensing parts of the two flow sensing units 4 are installed at the upstream position of the first heat exchange water inlet 251 through the side wall of the heat exchange water inlet pipe 26, for measuring the inflow of the geothermal water before heat exchange. Further, the sensing ends of the two flow sensing units 4 are located at different points upstream of the heat exchange water inlet 251, so as to monitor the flow rate of the geothermal water at at least two positions respectively.

[0110] According to the above setting mode, the main body of the temperature measuring unit 3 and the main body of the flow sensing unit 4 are arranged outside the measured object, avoiding the obstruction of the sensor unit to slow down the flow rate of the geothermal water entering the heat exchange area, and ensuring that the geothermal water can enter the heat exchange area at a higher temperature.

[0111] According to the embodiment of the utility model, the temperature measuring assembly and / or the flow assembly are in communication connection with the submersible pump.

[0112] In an exemplary embodiment, the signal output ends of the temperature measuring assembly and the flow assembly are connected to an external control unit, such as a data acquisition card, a microcontroller, a programmable logic controller (PLC), or a computer, etc., so as to collect the temperature difference and the water inflow data after the geothermal water is heat exchanged. In addition, the control unit is also connected to the control interface of the submersible pump, for adjusting the working power of the submersible pump.

[0113] According to the above setting mode, the temperature measuring assembly and the flow assembly are respectively responsible for collecting the temperature difference and the water inflow information after the geothermal water is heat exchanged, so as to calculate the heat exchange amount of the geothermal water flowing through the heat exchange side. Based on this calculation result, the operating parameters of the submersible pump, such as the power, etc., can be adjusted accordingly, so as to control the water inflow amount of the geothermal water. In this way, the circulating water which is heat exchanged with the geothermal water can be maintained or adjusted to a suitable temperature, so as to meet the heat energy demand of the external water environment.

[0114] The above describes the embodiments of the utility model. However, these embodiments are only for the purpose of illustration, and not for limiting the scope of the utility model. Although each embodiment is described above respectively, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the utility model is defined by the appended claims and their equivalents. Without departing from the scope of the utility model, those skilled in the art can make various substitutions and modifications, which all fall within the scope of the utility model.

Claims

1. A circulation mechanism for a geothermal well, characterized by comprising: The application relates to a wellhead device (1) for a geothermal well, comprising: a circulating water inlet pipe (11) and a circulating water return pipe (12) extending into the geothermal well and used as water inlet and return ends of an external water using device respectively; a heat exchanger (2) arranged in the geothermal well and having a circulating side and a heat exchanging side, the heat exchanging side being in communication with an external geothermal environment, the circulating water inlet pipe (11) and the circulating water return pipe (12) being in communication with the circulating side, and a bend pipe (13) being arranged between the circulating water return pipe (12) and the heat exchanger (2), the extending direction of the bend pipe (13) forming an angle with the flow direction of the circulating water so as to slow down the flow speed of the circulating water entering the heat exchanger (2). The bend pipe (13) is arranged to extend along a horizontal direction.

2. The circulation mechanism according to claim 1, characterized by, The wellhead device (1) comprises:

3. The circulation mechanism of claim 1, wherein a wellhead platform (19) arranged at the wellhead of the geothermal well; a circulating adapter plate (14) arranged on the wellhead platform (19), the upper ends of the circulating water inlet pipe (11) and the circulating water return pipe (12) being arranged on the circulating adapter plate (14); and a bend (15) arranged on the circulating adapter plate (14) and configured to connect the circulating water inlet pipe (11) or the circulating water return pipe (12) with the water using device. The wellhead device (1) further comprises:

4. The circulation mechanism of claim 3, wherein a cover body (16) arranged on the wellhead and shielding the circulating adapter plate (14) and the bend (15); and a cover plate (17) arranged on the cover body (16) in an openable and closable manner; wherein a lock (18) is further arranged between the cover plate (17) and the cover body (16). The heat exchanger (2) comprises:

5. The circulation mechanism according to any one of claims 1 to 4, characterized by, an inner pipe (21) arranged along a vertical direction; a heat exchanging pipe group (22) comprising a plurality of heat exchanging pipes and arranged in the inner pipe (21), the inner pipe (21) and the heat exchanging pipe group (22) outside a shell side forming the heat exchanging side, and a tube side in the heat exchanging pipes forming the circulating side; a partition plate (23) extending along the axial direction of the inner pipe (21) and having an upper water passing opening (231) formed at the upper portion so as to divide the heat exchanging side into a first part (211) and a second part (212) in communication with each other; wherein the circulating water flowing through the circulating side and the geothermal water flowing through the heat exchanging side are arranged to flow in opposite directions so as to form counter-flow heat exchange. The heat exchanger (2) further comprises:

6. The cycling mechanism of claim 5, wherein, a first joint (24) arranged at the upper portion of the inner pipe (21) and having a circulating water inlet opening (241) in communication with the circulating water inlet pipe (11) and a circulating water return opening (242) in communication with the circulating water return pipe (12), the circulating water inlet opening (241) and the circulating water return opening (242) being located on the two sides of the partition plate (23) so as to be isolated; and a second joint (25) arranged at the lower portion of the inner pipe (21) and having a heat exchanging water inlet opening (251) in communication with the first part (211) and a heat exchanging water return opening (252) in communication with the second part (212). The heat exchanger (2) comprises a plurality of heat exchanging water return openings (252), and the sum of the cross-sectional areas of each heat exchanging water return opening (252) is 90% to 100% of the cross-sectional area of the heat exchanging water inlet opening (251).

7. The cycling mechanism of claim 6, wherein, ​ 8. The cycling mechanism of claim 6, wherein, The heat exchanger (2) further comprises: A heat exchange water inlet pipe (26) in communication with the heat exchange water inlet (251) and coaxially arranged with the second joint (25).

9. The circulation mechanism of claim 8, wherein, The heat exchange water inlet pipe (26) comprises a first end on the heat exchange side and a second end outside the heat exchange side; The first end is provided with a water baffle (261) to communicate the heat exchange water inlet pipe (26) with the first part and isolate the second part.

10. The circulation mechanism according to any one of claims 6 to 9, characterized in that, The heat exchanger (2) further comprises: An outer pipe (27) sleeved on the outer side of the inner pipe (21), and a heat preservation material arranged between the inner pipe (21) and the outer pipe.

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