Diffuse flow type seafloor hydrothermal in-situ power generation device and power generation method

Abstract

The present application relates to the technical field of submarine hydrothermal power generation, in particular to a diffuse flow type submarine hydrothermal in-situ power generation device and a power generation method. The device comprises a high-efficiency heat exchange system, a terminal power system, and a thermal cycle pipeline system. The high-efficiency heat exchange system comprises a plurality of high-efficiency heat exchangers, which are arranged in the drill holes of the direct diffuse flow hydrothermal reservoir at a plurality of hydrothermal distribution points, and are connected in parallel between the high-efficiency heat exchangers and the terminal power system. The terminal power system converts the heat energy of the heat transfer medium into electric energy. The thermal cycle pipeline system comprises a plurality of thermal cycle pipelines, and the high-efficiency heat exchangers are connected in a circulating manner between the high-efficiency heat exchangers and the terminal power system through the thermal cycle pipelines. The device can effectively develop and utilize the widely distributed diffuse flow type submarine hydrothermal, and can realize large-scale submarine hydrothermal power generation, thereby greatly increasing the exploitation and utilization amount of submarine hydrothermal heat energy.

Description

Technical Field

[0001] This invention relates to the field of submarine hydrothermal power generation technology, and in particular to diffuse flow type submarine hydrothermal in-situ power generation device and power generation method. Background Technology

[0002] Hydrothermal vents are high-temperature bodies of water located at the boundaries of tectonic plates. They not only possess high temperatures but also contain abundant mineral resources, making them a marine energy source with immense development potential. The temperature of hydrothermal vents can typically reach approximately 400°C, while the surrounding cold seawater is only about 2-4°C, creating a significant temperature difference. This temperature difference makes hydrothermal vents on the deep seabed a potentially clean and renewable marine energy source.

[0003] Current underwater mining equipment suffers from short operating times and inconvenient charging, severely hindering the development of seabed mineral resources. If "co-extraction of hydrothermal fluids" technology could be implemented, the thermal energy contained in hydrothermal fluids could be effectively utilized to generate electricity, providing the necessary power for underwater mining equipment and supporting long-term deep-sea bottom mining operations.

[0004] "Black smoker" type concentrated flow hydrothermal vents have attracted attention due to their prominent eruption pattern, exhibiting a blowout-like pattern, and have been developed and used for hydrothermal power generation. However, concentrated flow type jet hydrothermal vents have the following drawbacks: (1) Due to their demanding formation conditions, they are sparsely distributed and difficult to utilize in a concentrated manner; (2) These hydrothermal vents have high chemical flux, which can cause chemical damage to equipment; (3) The eruptions are not continuous, and their ejection state is intermittent, resulting in low utilization; (4) The eruption activity is violent, with strong impact force, which can easily damage equipment. Therefore, currently, only some small-scale hydrothermal power generation devices have been developed for existing concentrated flow type jet hydrothermal vents.

[0005] Currently, thermoelectric power generation technology utilizing seafloor hydrothermal vents is inefficient. Small-scale hydrothermal power generation devices, primarily employing different semiconductors and Seebeck effect devices, generate relatively weak currents, failing to effectively utilize the vast temperature differences of seafloor hydrothermal resources. Furthermore, small power generation devices are highly susceptible to corrosion from hydrothermal vents and damage from ocean currents in the seafloor hydrothermal environment, making long-term operation and energy supply to underwater equipment difficult. Therefore, there is a need to develop highly efficient seafloor hydrothermal heat exchange devices to achieve large-scale development and utilization of hydrothermal energy, promoting the endurance of underwater equipment and advancing marine renewable energy technologies.

[0006] Dispersive hydrothermal vents, widely distributed in the seabed, do not form unobstructed eruption channels but rather diffusely overflow from seabed fissures. Compared to concentrated hydrothermal vents, they are more numerous, widely distributed, and more concentrated, often occurring in clusters, with less chemical precipitation and lower corrosivity. Due to their higher heat flux density, more stable activity, and gentler topographic conditions, dispersed hydrothermal vents are ideal heat sources for large-scale seabed thermal energy development and utilization. Compared to solely developing concentrated hydrothermal vents, utilizing the thermal energy of dispersed hydrothermal vents in subsurface reservoirs is an important direction for technological development in this field. If this stable seabed geothermal resource can be effectively utilized, it can not only provide clean energy for subsea equipment but also supply power to surface platforms via submarine cables, enabling larger-scale applications. Summary of the Invention

[0007] The purpose of this invention is to overcome the above-mentioned defects in the existing technology and to propose a diffuse flow type submarine hydrothermal vent in-situ power generation device and power generation method, which realizes the effective development and utilization of widely distributed diffuse flow type submarine hydrothermal vents, carries out large-scale submarine thermal power generation, and significantly increases the amount of submarine hydrothermal energy extracted and utilized.

[0008] The technical solution of this invention is: a diffuse flow type in-situ hydrothermal power generation device, comprising:

[0009] The high-efficiency heat exchange system includes several high-efficiency heat exchangers, which are installed in boreholes at several hydrothermal distribution points directly reaching the diffuse flow hydrothermal reservoir. The high-efficiency heat exchangers are connected in parallel with the terminal power system.

[0010] The terminal power system converts the thermal energy of the heat transfer medium into electrical energy;

[0011] The thermal circulation piping system includes an array of thermal circulation piping, and high-efficiency heat exchangers are connected to the terminal power system through the thermal circulation piping.

[0012] In this invention, the high-efficiency heat exchanger includes:

[0013] The main heat exchange section includes an outer tube of the heat exchanger and an inner tube of the heat exchanger located inside the outer tube.

[0014] The heat exchange section is reinforced and fixed to the outer wall and bottom of the outer tube of the heat exchanger.

[0015] The stabilization protection unit is fixedly installed on the upper outer side of the heat exchanger outer tube and the heat exchanger inner tube.

[0016] The outer tube and the inner tube of the heat exchanger are coaxially arranged, and there is a gap between the outer tube and the inner tube. The bottoms of the outer tube and the inner tube are connected.

[0017] The top end of the outer tube of the heat exchanger is connected to the working fluid inlet, and the top end of the inner tube of the heat exchanger is connected to the working fluid outlet.

[0018] The enhanced heat exchange section includes:

[0019] The phase change material temperature regulating layer includes a temperature regulating jacket fixedly wrapped around the side wall of the outer tube of the heat exchanger and a phase change material filled in the temperature regulating jacket;

[0020] The ribs are fixed to the annular outer wall of the upper part of the phase change material temperature regulating layer;

[0021] A metal foam layer is wrapped and fixed to the lower and bottom annular outer wall of the phase change material temperature regulating layer.

[0022] The stability protection unit includes:

[0023] The seepage prevention cover is fixedly installed on the upper part of the outer tube of the heat exchanger and is fixedly connected to the seabed surface outside the borehole.

[0024] A thermal stress buffer cover is placed over the top of the outer tube and the inner tube of the heat exchanger, and the bottom of the buffer cover is fixedly connected to the anti-seepage cover.

[0025] The terminal power system includes a working fluid detection box, a steam turbine, a condenser, and a compressor connected in sequence, with the working fluid detection box connected to the working fluid replenishment box;

[0026] Each high-efficiency heat exchanger is connected in parallel to the working fluid testing box via a thermal circulation pipeline. The compressor is connected to the corresponding high-efficiency heat exchanger via a thermal circulation pipeline. A circulation pump is installed on the thermal circulation pipeline connecting the compressor and the high-efficiency heat exchanger.

[0027] The thermal circulation pipeline includes: a working fluid input pipeline connecting the inner tube of the heat exchanger and the working fluid detection box, and a working fluid output pipeline connecting the compressor and the outer tube of the heat exchanger.

[0028] Valves are installed at both ends of the working medium output pipeline and the working medium input pipeline.

[0029] The present invention also includes a method for generating electricity using the above-mentioned diffuse flow type subsea hydrothermal in-situ power generation device, comprising the following steps:

[0030] S1. Using subsea directional drilling technology, drilling will be carried out at several points in the hydrothermal resource area to form a borehole group that directly reaches the diffuse flow hydrothermal reservoir.

[0031] S2. Place high-efficiency heat exchangers in the boreholes. Inside the high-efficiency heat exchangers, the heat transfer medium fully absorbs the heat from the external hot liquid and flows into the terminal power system through the thermal circulation pipeline.

[0032] S3. After the high-temperature heat transfer medium enters the terminal power system, the heat of the high-temperature heat transfer medium is used to generate electricity, converting the heat of the heat transfer medium into electrical energy, and cooling the heat transfer medium. The cooled heat transfer medium flows to the high-efficiency heat exchanger through the thermal circulation pipeline, forming a circulation of the heat transfer medium.

[0033] In step S2, the heat transfer medium exchanges heat with the hydrothermal liquid in the hydrothermal reservoir inside the outer tube of the high-efficiency heat exchanger. The heat transfer medium absorbs heat from the hydrothermal liquid, and the high-temperature heat transfer medium obtained by absorbing heat and heating up is collected in the inner tube of the heat exchanger and flows into the working medium detection box of the terminal power system through the working medium input pipe.

[0034] In step S3, the high-temperature heat transfer medium flowing out from several high-efficiency heat exchangers flows into the working medium testing box. The working medium testing box tests various parameters and specific components of the high-temperature heat transfer medium. The working medium replenishment box processes and replaces the high-temperature heat transfer medium according to the test results. The high-temperature heat transfer medium that meets the conditions flows into the steam turbine, drives the turbine to rotate, and drives the generator to generate electricity.

[0035] The electricity generated by the generator is converted by a DC-DC converter and stored in a battery, which then continuously provides power to the underwater equipment through a watertight charging port.

[0036] The heat transfer medium discharged from the power generation unit enters the condenser, where it is cooled and liquefied by the cooling effect of cold seawater. The cooled, low-temperature liquid heat transfer medium is then compressed into a liquid phase by the compressor and reinjected into the high-efficiency heat exchanger through a circulating pump on the working medium output pipeline.

[0037] The beneficial effects of this invention are:

[0038] This application achieves multi-point heat extraction from the same resource area by setting up multiple high-efficiency heat exchangers in parallel, which has the advantages of redundancy and reliability, and can make full and efficient use of hydrothermal resources in the area.

[0039] The high-efficiency heat exchanger in this application is designed to suit the characteristics of diffused flow hydrothermal fluids, resulting in high heat transfer efficiency and durability.

[0040] The power generation device and method proposed in this application can achieve a significant breakthrough in the field of submarine hydrothermal power generation, making it possible to efficiently develop the vast and stable resource of diffuse flow submarine hydrothermal vents, and contributing to the sustainable development of clean energy. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the overall structure of the diffuse flow type submarine hydrothermal in-situ power generation device described in this invention;

[0042] Figure 2 This is a schematic diagram of the circulating flow of the heat transfer medium of the present invention;

[0043] Figure 3 This is a schematic diagram of the terminal power system.

[0044] Figure 4 This is a schematic diagram of a high-efficiency heat exchanger;

[0045] Figure 5 This is a cross-sectional structural diagram of the fins of a high-efficiency heat exchanger.

[0046] Figure 6 This is a cross-sectional structural diagram of the metal foam layer in a high-efficiency heat exchanger.

[0047] Figure 7 This is a schematic diagram of the structure of a heat circulation pipeline.

[0048] In the diagram: 1. High-efficiency heat exchanger; 2. Thermal circulation piping system; 3. Terminal power system; 4. Submarine hydrothermal reservoir; 5. Heat exchanger outer tube; 6. Heat exchanger inner tube; 7. Phase change material temperature regulating layer; 8. Metal foam layer; 9. Fins; 10. Fixing device; 11. Leak-proof cover; 12. Thermal stress buffer cover; 13. Working fluid inlet; 14. Working fluid outlet; 15. Working fluid input pipeline; 16. Working fluid output pipeline; 17. Valve; 18. Working fluid detection box; 19. Working fluid replenishment box; 20. Steam turbine; 21. Generator; 22. Condenser; 23. DC-DC converter; 24. Battery; 25. Controller; 26. Compressor; 27. Circulation pump; 28. Protection box; 29. ​​Second insulation layer; 30. Watertight charging port; 31. Backup battery; 32. Monitor; 33. Heat dissipation fins; 34. First insulation layer; 35. Pipeline vibration damping mechanism; 36. Pressure and temperature sensor. Detailed Implementation

[0049] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0050] Specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many ways other than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0051] Example 1

[0052] The diffuse flow type subsea hydrothermal in-situ power generation device of the present invention includes a high-efficiency heat exchange system and a terminal power system 3. The high-efficiency heat exchange system is connected to the terminal power system 3 through a thermal circulation pipeline system 2. Within the high-efficiency heat exchange system, effective heat exchange between the heat transfer medium and the hydrothermal fluid is achieved. The heated heat transfer medium in the high-efficiency heat exchange system is transported to the terminal power system 3 through the thermal circulation pipeline system 2. Within the terminal power system 3, the conversion and output of thermal energy into electrical energy is realized.

[0053] The heat transfer medium forms a closed loop within the device. After absorbing heat and heating up in the high-efficiency heat exchange system, the heat transfer medium flows into the terminal power system 3 through the thermodynamic circulation pipeline system 2. The terminal power system 3 converts the heat of the heat transfer medium into electrical energy, thus lowering the temperature of the heat transfer medium. The cooled heat transfer medium then flows back into the high-efficiency heat exchange system through the thermodynamic circulation pipeline system 2 to absorb heat again, repeating the above cycle. Continuous power generation is achieved during the circulation of the heat transfer medium.

[0054] In this embodiment, supercritical carbon dioxide (S-CO2) is used as the heat transfer medium. This medium features high heat exchange efficiency, large density variation, and good chemical inertness. It also has a large phase change heat extraction capacity, allowing for more complete utilization of the hydrothermal fluid's heat. Furthermore, this medium exhibits low corrosiveness to the components it flows through, thus extending the overall lifespan of the device. Additionally, in the event of a rupture in the transport pipeline, compressed supercritical carbon dioxide will be ejected outwards, preventing seawater seepage and damage to internal equipment. Pressure fluctuations are easily detected, allowing for timely valve closure to prevent further damage.

[0055] Because this charging device is a large-scale power generation unit, the high-efficiency heat exchange system includes several high-efficiency heat exchangers 1. Through preliminary seafloor hydrothermal exploration, several heat source hotspots were located in a vast diffuse flow area. Using subsea directional drilling technology, vertical drilling was conducted at these hotspots, reaching the seafloor hydrothermal reservoir 4. Within the reservoir, a large amount of flowing, un-erupted hydrothermal fluid flows through rock fissures and faults. Each high-efficiency heat exchanger is placed inside a borehole in the target hydrothermal reservoir. The corresponding thermal circulation piping system 2 includes multiple thermal circulation pipes.

[0056] This application includes multiple high-efficiency heat exchangers located at different positions. Each high-efficiency heat exchanger 1 is connected to the terminal power system 3 via a thermal circulation pipeline, thus the multiple high-efficiency heat exchangers 1 are arranged in parallel. By using multiple high-efficiency heat exchangers connected in parallel, multi-pipe parallel mining is achieved. The high-temperature working fluid obtained after heat exchange is uniformly collected and flows into the terminal power system for power generation. The above parallel connection method can significantly improve the stability of heat acquisition and avoid the limitations of a single heat extraction point. Even if some of the high-efficiency heat exchangers or thermal circulation pipelines are damaged, it will not affect the normal operation of the entire device.

[0057] The high-efficiency heat exchanger 1 includes a main heat exchange section, an enhanced heat exchange section, and a stabilization and protection section. The main heat exchange section enables heat exchange between the heat transfer medium and the hydrothermal fluid. The enhanced heat exchange section improves heat exchange efficiency and enhances the overall stability of the heat exchanger. The stabilization and protection section protects the entire heat exchanger.

[0058] The main heat exchange section includes an inner tube 6 and an outer tube 5. The inner tube 6 is disposed inside the outer tube 5 and the two tubes are coaxially arranged. The top of the outer tube 5 is connected to the working fluid inlet 13, and the top of the inner tube 6 is connected to the working fluid outlet 14. There is a gap between the outer wall of the inner tube 6 and the inner wall of the outer tube 5. The bottoms of the inner tube 6 and the outer tube 5 are interconnected, thereby enabling the flow of the heat transfer medium between the inner and outer tubes.

[0059] The outer tube 5 of the heat exchanger is made of a high-strength, high-thermal-conductivity, and corrosion-resistant metallic material. In this embodiment, the outer tube is made of Inconel 718 alloy or TC4 alloy. The inner tube 6 of the heat exchanger is made of a non-metallic material with poor thermal conductivity to effectively reduce the problem of thermal short-circuiting between the inner and outer tubes, thereby maximizing heat exchange efficiency and stability. In this embodiment, the inner tube is made of high-density polyethylene.

[0060] After the heat transfer medium flows into the outer tube 5 of the heat exchanger from the inlet 13, it flows from top to bottom along the gap between the outer tube 5 and the inner tube 6 of the heat exchanger under the combined action of the circulating pump and gravity. During the flow of the heat transfer medium, it comes into full contact with and exchanges heat with the hydrothermal reservoir on the outside. The low-temperature heat transfer medium gradually absorbs heat from the hydrothermal fluid and the surrounding rock and heats up.

[0061] The high-temperature heat transfer medium, having absorbed heat, flows to the bottom of the outer tube 5 of the heat exchanger and collects there. Under the pressure of the continuously entering heat transfer medium, the high-temperature heat transfer medium enters the inner tube 6 of the heat exchanger and flows from bottom to top within it. When the high-temperature heat transfer medium reaches the working medium outlet 14 at the top of the inner tube, it flows out directly from the outlet 14.

[0062] The main heat exchange section is an integral structure employing a dual-working-medium circulation system. This means the heating medium outside the heat exchange tubes and the heat transfer medium inside the tubes do not come into contact or mix. The external heating medium will not enter the heat exchange tubes, thus preventing damage to their internal structure. This completely isolates the heat exchanger from external corrosive environments, effectively preventing corrosion and blockage, and ensuring the long-term, stable, and reliable operation of the entire high-efficiency heat exchanger.

[0063] The enhanced heat exchange section includes fins 9, a metal foam layer 8, and a phase change material temperature regulating layer 7. The fins 9 and the metal foam layer 8 are disposed on the outer surface of the high-efficiency heat exchanger. The fins and the metal foam layer not only protect the heat exchanger and significantly improve its resistance to corrosion by chemical components in the hydrothermal fluid, but also enhance the heat exchange effect between the heat exchanger and the hydrothermal fluid and surrounding rock, ensuring the safety and reliability of the entire device.

[0064] A phase change material temperature regulating layer 7 is fixed on the outer wall of the heat exchanger outer tube 5. In this application, the phase change material temperature regulating layer 7 includes a temperature regulating jacket, which is fixedly wrapped around the outer wall of the heat exchanger outer tube 5 and is filled with phase change material.

[0065] The phase change material is an inorganic phase change thermal storage material. In this embodiment, a fluoride salt plasma material is selected, which has a phase change temperature of over 300℃ and is resistant to high temperatures. The phase change material temperature regulating layer has the functions of heat conduction, heat absorption, heat storage, and heat release.

[0066] The phase change material (PCM) temperature-regulating layer serves several functions. First, it improves heat exchange uniformity: Due to the uneven temperature distribution caused by the non-uniform flow of diffused hydrothermal fluids, PCM maintains the phase change process within a certain temperature range, exhibiting self-regulating temperature control. This layer improves the uneven heat distribution within the heat exchanger, suppressing localized overheating and making the entire heat exchange process more uniform. Second, it protects equipment safety: Preventing damage to equipment materials from localized overheating; PCM acts as a temperature buffer, ensuring a reasonable heat distribution and preventing excessive heat accumulation that could cause thermal damage. Third, it enhances heat exchange efficiency: The phase change process absorbs or releases a large amount of latent heat, which can also be considered part of the heat exchange, increasing the overall heat exchange volume and improving heat exchange efficiency. Fourth, it ensures working fluid quality: The isostatic effect of the PCM layer helps maintain the working fluid within a suitable temperature range, preventing chemical deterioration or vaporization caused by overheating, ensuring its thermophysical parameters are within acceptable limits, effectively preventing uneven heat distribution in the hydrothermal fluid, and ensuring more uniform heating and heat exchange throughout the entire heat exchanger.

[0067] As the diffused hydrothermal fluid continuously flows out, the phase change material (PCM) temperature-regulating layer absorbs heat from the fluid and releases a significant amount of latent heat, forming a heat buffer. This results in a more uniform temperature distribution on the outer tubes of the heat exchanger, ensuring more even heating. When a small amount of hydrothermal fluid temporarily flows out, the PCM temperature-regulating layer can continuously release its stored heat, providing continuous heat dissipation. Even during the heat release process, the PCM temperature-regulating layer can still heat the heat transfer medium flowing into the outer tubes of the heat exchanger, ensuring continuous power generation.

[0068] The fins 9 are fixed to the upper annular portion of the outer side of the phase change material temperature regulating layer 7. Positioned in the upper part of the heat exchanger, in a region with lower ambient temperature, the fins prevent direct contact between the outer tubes of the heat exchanger and the external hydrothermal fluid, significantly improving resistance to corrosion from chemical components in the hydrothermal fluid. Simultaneously, the fins act as heat conductors, enhancing the heat exchange effect between the heat transfer medium inside the outer tubes and the surrounding rock. Furthermore, the large size and high rigidity of the fins provide stability to the upper part of the main heat exchange section, as well as resistance to pressure from ocean current disturbances and crustal movements, thus enhancing the structural stability of the upper part of the main heat exchange section.

[0069] A metal foam layer 8 is wrapped and fixed to the lower annular part and bottom of the phase change material temperature regulating layer 7. The metal foam layer is located in the lower part of the heat exchanger and in the area with a higher peripheral temperature. The metal foam layer is made of metal foam. Metal foam is a porous medium with large pores, possessing a large specific surface area, high porosity, excellent thermal conductivity, and good stiffness and elastic limit.

[0070] In the initial stage of heat exchanger operation, as the hydrothermal fluid penetrates from the lower formation porosity into the high-porosity metal foam, the flow velocity increases. At this point, the hydrothermal fluid can make more thorough contact with the outer tubes of the heat exchanger, resulting in high heat transfer efficiency between the hydrothermal fluid and the heat transfer medium inside the outer tubes. During operation, the hydrothermal fluid reacts to produce precipitates, which adhere to the surface of the metal foam. Compared to hydrothermal fluid precipitates, the precipitates bound to the metal foam have enhanced thermal conductivity. The metal foam not only improves the heat transfer efficiency between the hydrothermal fluid and the heat exchanger but also provides structural support, enhancing the heat exchanger's vibration resistance to withstand the harsh seabed environment.

[0071] During the use of heat exchangers, the metal foam layer not only enhances the heat transfer between the heat transfer medium and the hot liquid inside the heat exchanger, maintaining a good heat transfer effect, but also increases the thickness of the bottom of the heat exchanger to reduce and protect the bottom of the heat exchange tube from impact. At the same time, the metal thermal conductive layer formed by the later combination of hot liquid deposits and metal foam on the outside of the heat exchanger reduces the vibration and flow impact inside the heat exchange tube, thus improving the stability of the heat exchanger.

[0072] During the contact process between the high-efficiency heat exchanger and the hydrothermal fluid, the heat from the hydrothermal fluid passes sequentially through the fins 9 / metal foam layer 8, the phase change material temperature regulating layer 7, and the outer tube 5 of the heat exchanger, ultimately reaching the heat transfer medium inside the outer tube. By enhancing the heat exchange section, firstly, the heat transfer efficiency between the hydrothermal fluid and the heat transfer medium can be improved, enhancing the effective transfer and conversion of heat energy from the hydrothermal reservoir to the heat transfer medium; secondly, it plays a certain role in stabilizing the high-efficiency heat exchanger, improving its resistance to damage.

[0073] The stabilization protection unit includes a seepage-proof cover 11 and a thermal stress buffer cover 12. The seepage-proof cover 11 is fixed to the upper outer side of the heat exchanger outer tube 5, and is arranged in a ring along the outer side of the heat exchanger outer tube 5. The seepage-proof cover 11 is located above the fins 9. The seepage-proof cover 11 is fixed to the seabed surface outside the borehole by a fixing device 10. The seepage-proof cover can fix the position of the heat exchanger, prevent the seepage-proof cover from sinking, and prevent cold seawater from seeping into the reservoir and mixing with the hydrothermal fluid, thereby reducing the hydrothermal fluid temperature and improving heat exchange efficiency. The fixing device can be a screw or other components.

[0074] A thermal stress buffer cover 12 is provided on the top of the high-efficiency heat exchanger, and the thermal stress buffer cover 12 is fixedly connected to the top surface of the anti-seepage cover 11. The thermal stress buffer cover 12 covers the top outer side of the heat exchanger's outer tube and inner tube, and the inner surface of the thermal stress buffer cover 12 is provided with a first insulation layer 34. The thermal stress buffer cover 12 protects the heat exchanger's outer tube and inner tube, isolating them from the external cold seawater and preventing damage to the device caused by shear stress generated by excessive temperature difference.

[0075] The terminal power system 3 is located in a flat area around the wellhead and includes a working fluid testing box 18, a steam turbine 20, a generator 21, a condenser 22, a compressor 26, and a circulating pump 27. The working fluid testing box 18, steam turbine 20, generator 21, condenser 22, compressor 26, and circulating pump 27 are all located inside a protective box 28, and the inner wall of the protective box 28 is provided with a second insulation layer 29.

[0076] All the working fluid outlets 14 of the aforementioned high-temperature heat exchangers are connected to the inlet of the working fluid testing tank via a thermal circulation pipeline system. After absorbing heat, the high-temperature heat transfer fluid flows out of the high-temperature heat exchanger and into the working fluid testing tank 18. The working fluid testing tank 18 is equipped with a testing mechanism to detect the composition of the heat transfer fluid. Simultaneously, the working fluid testing tank monitors parameters such as flow rate, temperature, and pressure of the heat transfer fluid in real time. If the parameters of the heat transfer fluid do not meet the standards or if there are unqualified impurities in the heat transfer fluid, the high-temperature heat transfer fluid is transferred to the working fluid replenishment tank 19 for processing and replacement. In this application, the working fluid replenishment tank 19 is fixedly connected to the top surface of the working fluid testing tank 18.

[0077] By setting up a unified working fluid testing box 18, the hydrothermal energy at different points in a wide diffuse flow area can be effectively utilized, improving the stability of heat acquisition, avoiding the influence of instability at a single location, and adjusting and ensuring the quality of the working fluid entering subsequent power generation equipment.

[0078] The outlet of the working fluid testing tank 18 is connected to the inlet of the steam turbine 20. After the high-temperature heat transfer fluid, having passed the adjustment, flows from the working fluid testing tank into the steam turbine 20, it drives the turbine to rotate, thereby driving the generator 21 to generate electricity. The outlet of the steam turbine 20 is connected to the inlet of the condenser 22 via a connecting pipe.

[0079] The condenser 22 is fixed to the top of the protective box 28, and several heat dissipation fins 33 are provided on the outer surface of the top of the protective box where the condenser is located. Utilizing the density difference created by heat exchange with the surrounding cold seawater, natural flow is achieved, enhancing heat transfer. Positioning the condenser on top of the protective box does not affect other parts of the unit. The fins provide cooling, resisting large temperature variations and enhancing heat exchange efficiency. The heat transfer fluid discharged from the generator enters the condenser 22 and, through the heat dissipation fins 33 on the top of the protective box, utilizes the low temperature of the surrounding cold seawater to cool the heat transfer fluid inside the condenser 22, causing it to liquefy. This application fully utilizes the low temperature of the surrounding cold seawater to cool and condense the heat transfer fluid, eliminating the need for an additional cooling system, simplifying the device, and reducing costs.

[0080] The outlet of condenser 22 is connected to the inlet of compressor 26 via a connecting pipe. After cooling, the low-temperature liquid heat transfer medium enters compressor 26 and is compressed into a liquid state by the compressor. The outlet of compressor 26 is connected to the working fluid inlet of high-temperature heat exchanger via a connecting pipe. A circulation pump 27 is installed on this connecting pipe. Under the action of the circulation pump, the low-temperature heat transfer medium compressed by the compressor is reinjected into high-temperature heat exchanger 1, starting a new circulation of heat transfer medium.

[0081] The electricity generated by generator 21 is converted by DC converter 23 and stored in battery 24, and continuously provides power to underwater equipment through watertight charging port 30.

[0082] The thermal circulation piping system includes an array of thermal circulation pipes connecting a high-temperature heat exchanger and a terminal power system. Each set of thermal circulation pipes includes a working fluid inlet pipe 15 connecting the working fluid outlet and the working fluid testing box, and a working fluid outlet pipe 16 connecting the compressor and the working fluid inlet. A circulation pump 27 is installed on the working fluid outlet pipe 16. Valves 17 are provided at both ends of the working fluid inlet pipe 15 and the working fluid outlet pipe 16 for emergency pipe shut-off. In this embodiment, the valves are automatically controlled valves. Pipe vibration damping mechanisms 35 are provided at both ends of the working fluid inlet pipe 15 and the working fluid outlet pipe 16. These damping mechanisms can suppress the impact of submarine currents and other external forces on the pipes, ensuring the structural integrity.

[0083] The working medium inlet pipe 15 and the working medium outlet pipe 16 are also equipped with pipe fixing mechanisms to secure the pipes to the seabed and prevent drifting and displacement. To reduce heat loss, the working medium inlet pipe and the working medium outlet pipe are equipped with an external thermal insulation layer, which improves the stability and thermal insulation of the pipes.

[0084] The device also includes a control system, which comprises a backup battery 31, a controller 25, a monitor 32, and a pressure and temperature sensor 36. The controller 25 and the monitor 32 are housed within the protection box 28 of the terminal power system. The controller 25 is electrically connected to the monitor 32, which monitors changes in battery charge in real time. Based on these changes, the controller 25 adjusts valve 17 to control the flow rate of the heat transfer medium, optimizing power generation to meet load demands.

[0085] The controller 25 is electrically connected to the pressure and temperature sensor 36, which is installed on the pipe walls of the working fluid inlet pipe 15 and the working fluid outlet pipe 16. The pressure and temperature sensor 36 is used to monitor the working status of the pipes in real time. When a leak occurs in the pipe, the pressure or temperature value monitored by the pressure and temperature sensor 36 will change significantly. At this time, the controller 25 will immediately close the valves 17 at both ends of the pipe, isolating the local pipe from other components of the device, preventing seawater backflow from contaminating the high-efficiency heat exchanger and the terminal power system, and ensuring that the device can operate normally.

[0086] Example 2

[0087] This application also discloses a method for generating electricity using the diffuse flow type subsea hydrothermal in-situ power generation device described in the embodiments, including the following steps.

[0088] The first step involves accurately locating the widely distributed diffuse flow hydrothermal resource areas and hydrothermal vent distribution points through seabed topography analysis and thermal radiation measurement. This process obtains the corresponding geological, hydrogeological, and geothermal geological conditions of the target strata. Based on the exploration results, a mining plan is developed. Subsea directional drilling technology is used to drill at multiple points in the hydrothermal resource area, forming a borehole group that directly reaches the diffuse flow hydrothermal reservoir.

[0089] The second step involves placing high-efficiency heat exchangers 1 into the boreholes. Inside the outer tube 5 of the high-efficiency heat exchanger, the heat transfer medium exchanges heat with the hydrothermal reservoir. The heat transfer medium fully absorbs the heat from the hydrothermal reservoir, and the high-temperature heat transfer medium obtained by absorbing heat and raising its temperature is collected in the inner tube 6 of the heat exchanger and flows into the working medium detection box 18 of the terminal power system 3 through the working medium input pipe 15.

[0090] Thirdly, after the high-temperature heat transfer medium enters the terminal power system, it utilizes its heat to generate electricity, converting the heat of the heat transfer medium into electrical energy. Simultaneously, the heat transfer medium is cooled, and the cooled medium flows through the working fluid output pipe 16 into the outer tube of the high-efficiency heat exchanger, thus forming a heat transfer medium circulation. During this circulation, the heat transfer medium continuously absorbs heat from the hydrothermal fluid and converts the heat of the hydrothermal fluid into electrical energy, thereby achieving power generation.

[0091] The high-temperature heat transfer medium flows into the working medium testing box 18. The working medium testing box 18 tests various parameters and specific components of the high-temperature heat transfer medium. Based on the test results, the high-temperature heat transfer medium is processed and replaced through the working medium replenishment box 19. The high-temperature heat transfer medium that meets the relevant conditions flows into the steam turbine 20, drives the turbine to rotate, and drives the generator 21 to generate electricity.

[0092] The electricity generated by the generator is converted by the DC-DC converter 23 and stored in the battery 24, continuously providing power to the underwater equipment through the watertight charging port 30. The heat transfer medium discharged from the generator enters the condenser 22, where it is cooled and liquefied by the cooling effect of cold seawater. The cooled low-temperature liquid heat transfer medium is compressed into a liquid state by the compressor 26 and reinjected into the high-efficiency heat exchanger 1 through the circulation pump 27 on the working medium output pipe 16, starting a new circulation flow.

[0093] The above provides a detailed description of the diffuse flow type submarine hydrothermal in-situ power generation device and method provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from the principles of the invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A diffuse seafloor hydrothermal in-situ power generation apparatus, characterized by, include: The high-efficiency heat exchange system includes several high-efficiency heat exchangers, which are installed in boreholes at several hydrothermal distribution points directly reaching the diffuse flow hydrothermal reservoir. The high-efficiency heat exchangers are connected in parallel with the terminal power system. The terminal power system converts the thermal energy of the heat transfer medium into electrical energy; The thermal circulation piping system includes an array of thermal circulation piping, and high-efficiency heat exchangers are connected to the terminal power system through the thermal circulation piping. The high-efficiency heat exchanger includes: The main heat exchange section includes an outer tube of the heat exchanger and an inner tube of the heat exchanger located inside the outer tube. The heat exchange section is reinforced and fixed to the outer wall and bottom of the outer tube of the heat exchanger. The stabilization protection unit is fixedly installed on the upper outer side of the heat exchanger outer tube and the heat exchanger inner tube; The enhanced heat exchange section includes: The phase change material temperature regulating layer includes a temperature regulating jacket fixedly wrapped around the side wall of the outer tube of the heat exchanger and a phase change material filled in the temperature regulating jacket; The ribs are fixed to the annular outer wall of the upper part of the phase change material temperature regulating layer; A metal foam layer is wrapped and fixed to the lower and bottom annular outer wall of the phase change material temperature regulating layer; The stability protection unit includes: The seepage prevention cover is fixedly installed on the upper part of the outer tube of the heat exchanger and is fixedly connected to the seabed surface outside the borehole. A thermal stress buffer cover is placed over the top of the outer tube and the inner tube of the heat exchanger, and the bottom of the buffer cover is fixedly connected to the anti-seepage cover.

2. The diffused subsea hydrothermal in-situ power generation device according to claim 1, characterized in that, The outer tube and the inner tube of the heat exchanger are coaxially arranged, and there is a gap between the outer tube and the inner tube. The bottoms of the outer tube and the inner tube are connected. The top end of the outer tube of the heat exchanger is connected to the working fluid inlet, and the top end of the inner tube of the heat exchanger is connected to the working fluid outlet.

3. The diffused subsea hydrothermal in-situ power generation device according to claim 1, characterized in that, The terminal power system includes a working fluid detection box, a steam turbine, a condenser, and a compressor connected in sequence, with the working fluid detection box connected to the working fluid replenishment box; Each high-efficiency heat exchanger is connected in parallel to the working fluid testing box via a thermal circulation pipeline. The compressor is connected to the corresponding high-efficiency heat exchanger via a thermal circulation pipeline. A circulation pump is installed on the thermal circulation pipeline connecting the compressor and the high-efficiency heat exchanger.

4. The diffused subsea hydrothermal in-situ power generation device according to claim 3, characterized in that, The thermal circulation pipeline includes: a working fluid input pipeline connecting the inner tube of the heat exchanger and the working fluid detection box, and a working fluid output pipeline connecting the compressor and the outer tube of the heat exchanger. Valves are installed at both ends of the working medium output pipeline and the working medium input pipeline.

5. A method for generating electricity using any one of the diffused subsea hydrothermal in-situ power generation devices described in claims 1-4, characterized in that, Includes the following steps: S1. Using subsea directional drilling technology, drilling will be carried out at several points in the hydrothermal resource area to form a borehole group that directly reaches the diffuse flow hydrothermal reservoir. S2. Place high-efficiency heat exchangers in the boreholes. Inside the high-efficiency heat exchangers, the heat transfer medium fully absorbs the heat from the external hot liquid and flows into the terminal power system through the thermal circulation pipeline. S3. After the high-temperature heat transfer medium enters the terminal power system, the heat of the high-temperature heat transfer medium is used to generate electricity, converting the heat of the heat transfer medium into electrical energy, and cooling the heat transfer medium. The cooled heat transfer medium flows to the high-efficiency heat exchanger through the thermal circulation pipeline, forming a circulation of the heat transfer medium.

6. The method according to claim 5, characterized in that, In step S2, the heat transfer medium exchanges heat with the hydrothermal liquid in the hydrothermal reservoir inside the outer tube of the high-efficiency heat exchanger. The heat transfer medium absorbs heat from the hydrothermal liquid, and the high-temperature heat transfer medium obtained by absorbing heat and heating up is collected in the inner tube of the heat exchanger and flows into the working medium detection box of the terminal power system through the working medium input pipe.

7. The method according to claim 5, characterized in that, In step S3, the high-temperature heat transfer medium flowing out from several high-efficiency heat exchangers flows into the working medium testing box. The working medium testing box tests various parameters and specific components of the high-temperature heat transfer medium. The working medium replenishment box processes and replaces the high-temperature heat transfer medium according to the test results. The high-temperature heat transfer medium that meets the conditions flows into the steam turbine, drives the turbine to rotate, and drives the generator to generate electricity. The electricity generated by the generator is converted by a DC-DC converter and stored in a battery, which then continuously provides power to the underwater equipment through a watertight charging port. The heat transfer medium discharged from the power generation unit enters the condenser, where it is cooled and liquefied by the cooling effect of cold seawater. The cooled, low-temperature liquid heat transfer medium is then compressed into a liquid phase by the compressor and reinjected into the high-efficiency heat exchanger through a circulating pump on the working medium output pipeline.

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