Seawater desalination and power generation system utilizing gas compression-hydrate two-stage energy storage

Abstract

The invention relates to the technical field of energy storage, seawater desalination and power generation, and discloses a seawater desalination and power generation system utilizing gas compression-hydrate two-stage energy storage, which comprises a gas compression energy storage module, a hydrate formation energy storage module, a hydrate decomposition module, a power generation module and a cold energy recovery module, low-pressure gas is subjected to compression energy storage through green electricity, waste electricity or redundant electricity, high-pressure gas and seawater act to form hydrate for secondary energy storage, the energy storage density is improved, hydrate decomposition is conducted in the peak period of power demand, gas is released, and a motor is driven to generate electricity; low-temperature desalination is generated after the hydrate is decomposed, the seawater is pre-cooled through the heat exchanger and circularly enters the hydrate forming kettle to provide pre-cooling water for subsequent hydrate forming energy storage, and fresh water flowing out of the heat exchanger can be used as a fresh water resource. According to the invention, seawater desalination and power generation can be carried out by using gas compression-hydrate two-stage energy storage.

Description

Technical Field

[0001] The present invention relates to the technical fields of energy storage, seawater desalination and power generation, and specifically provides a seawater desalination and power generation system using gas compression - hydrate secondary energy storage. Background Art

[0003] Hydrate energy storage technology is a new energy storage method. By forming hydrates through the reaction of gas and water under specific temperature and pressure conditions, the storage and release of energy are achieved. Compared with traditional energy storage technologies, hydrate energy storage has advantages such as high energy storage density and environmental friendliness. In addition, the gas released during the decomposition phase change process of hydrates can drive an expander or turbine to generate electricity and produce fresh water, enabling the coordinated optimization of energy comprehensive utilization and fresh water production.

[0004] Currently, there is little research on the combination of air compression energy storage and hydrate energy storage, and a mature technical system has not been formed yet. The present invention proposes a secondary energy storage system combining air compression and hydrate phase change energy storage. It uses renewable energy or low - cost electricity to compress gas, stores energy through hydrate phase change, decomposes hydrates to release gas to drive a generator to generate electricity during peak electricity demand periods, and uses the low temperature generated by hydrate decomposition to pre - cool seawater. The pre - cooled seawater is circulated into the hydrate formation tank to provide pre - cooled water for subsequent hydrate formation and energy storage. This system can effectively improve energy utilization efficiency, reduce the energy consumption of seawater desalination, and provide reliable energy and fresh water supply solutions for islands, coastal areas, ocean - going ships and offshore oil and gas platforms, etc. Summary of the Invention

[0005] The purpose of the present invention is to provide a seawater desalination and power generation system using gas compression - hydrate secondary energy storage to solve the problems raised in the above background art.

[0006] To solve the above - mentioned technical problems, the present invention provides the following technical solutions: A seawater desalination and power generation system using gas compression - hydrate secondary energy storage, wherein the gas compression energy storage module is used to drive an air compressor through green electricity, waste electricity or surplus electricity to compress low - pressure gas to high pressure for primary energy storage;

[0007] The hydrate formation energy storage module is used to receive high - pressure gas and react with seawater to form hydrates to achieve secondary energy storage;

[0008] The hydrate decomposition energy release module is used to decompose hydrates during peak electricity demand periods, release gas, and produce low - temperature fresh water;

[0009] The power generation module uses the gas released by hydrate decomposition to drive an expander or turbine to generate electricity, improving energy utilization efficiency;

[0010] For the cold energy recovery module, the low-temperature fresh water generated by the endothermic decomposition of hydrate passes through a heat exchanger to precool the fresh seawater, which can enhance the energy utilization efficiency, increase the subsequent hydrate formation rate, and obtain fresh water resources at the same time.

[0011] Preferably, the gas compression energy storage module can be driven by wind energy, photovoltaic energy or surplus electricity from the power grid to improve the renewable energy utilization rate of the system.

[0012] Preferably, the hydrate formation energy storage module includes a stirring device for optimizing the hydrate formation rate and improving the overall energy storage efficiency.

[0013] Preferably, the power generation module uses the gas released by the decomposition of hydrate to drive an expander or turbine for power generation, improving the energy utilization rate.

[0014] Preferably, the cold energy recovery module includes a heat exchanger for recycling the cold energy generated by the decomposition of low-temperature hydrate to improve the thermal energy management ability of the system.

[0015] Preferably, the hydrate-forming gas in the hydrate formation energy storage module can be (hydrate-forming gases such as methane, ethane, propane, carbon dioxide, hydrogen, nitrogen, etc.).

[0016] Preferably, hydrate promoters (such as cyclopentane, tetrahydrofuran, SDS, etc.) and nanoparticles can be added to the hydrate formation energy storage module to accelerate hydrate formation, thereby accelerating the energy storage efficiency.

[0017] Preferably, while energy storage and conversion are carried out based on this system, available fresh water resources can also be generated, improving the energy utilization efficiency and providing a fresh water supply solution.

[0018] Preferably, the system is applicable to environments such as islands, coastal areas, ocean-going ships, and offshore oil and gas platforms, providing efficient, environmentally friendly, and sustainable energy and fresh water supplies.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0020] 1. In the present invention, gas compression is used for primary energy storage, and compressed gas forms hydrates with seawater for secondary energy storage, realizing energy storage with a higher energy density and providing an environmentally friendly and sustainable energy supply solution.

[0021] 2. The present invention can not only generate electricity but also achieve seawater desalination at the same time, providing valuable fresh water resources, and is especially suitable for freshwater-deficient areas such as islands, coastal areas, and ocean-going ships.

[0022] 3. In the design of the present invention, full consideration is given to the recovery and recycling of the cold energy generated by hydrate decomposition, reducing the operating cost, improving the economic benefit, and adapting to various application scenarios. Brief Description of the Drawings

[0023] Figure 1 This is a module diagram of a seawater desalination and power generation system using gas compression - hydrate secondary energy storage proposed by the present invention.

[0024] Figure 2 This is a flow chart of a seawater desalination and power generation system using gas compression - hydrate secondary energy storage proposed by the present invention.

[0025] Wherein: 1. Green electricity, waste electricity or surplus electricity; 2. Compressor; 3. High - pressure gas outlet; 4. Seawater injection port; 5. Hydrate formation tank; 6. Brine outlet; 7. Hydrate decomposition tank; 8. Hydrate decomposition gas outlet; 9. Cold fresh water (hydrate - decomposed water); 10. Normal - temperature seawater; 11. Heat exchanger; 12. Cooling seawater outlet; 13. Expander or turbine; 14. Low - pressure hydrate decomposition gas storage tank; 15. Cooling seawater storage tank; 16. Dryer. Detailed Embodiments

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0027] Embodiment 1

[0028] By organically combining air compression and hydrate energy storage, and using wind energy, photovoltaic energy or low - cost electricity to drive the air compressor 2, the hydrate - forming gas is compressed to high pressure to achieve primary energy storage. By regulating the gas pressure and temperature conditions, the compressed air is discharged from the outlet 3 and enters the hydrate formation tank 5 to react with seawater to form hydrates, achieving secondary energy storage, and discharging the brine from the outlet 6. During peak electricity consumption, the hydrate decomposition module 4 is used to decompose the hydrates in the hydrate decomposition tank 7, and the released gas drives the expander or turbine 13 to generate electricity, thereby improving the overall energy efficiency of the system. In addition, the cold energy released during the decomposition of hydrates can be used to precool seawater through the heat exchanger 11 and improve the subsequent hydrate energy storage efficiency, and the fresh water generated by the decomposition of hydrates can be used as directly - utilizable fresh water resources.

[0029] This system includes the following components:

[0030] 1. Air compression module 2: This system uses an efficient air compressor 2 to compress low - pressure air into high - pressure gas to form primary energy storage using wind energy, photovoltaic power generation or low - cost electricity in the power grid (such as off - peak electricity at night). This design can not only make full use of renewable energy but also effectively reduce the operating cost.

[0031] 2. Hydrate formation and energy storage module 3: High-pressure gas is introduced into the hydrate formation tank 5 and mixed with seawater under specific temperature and pressure conditions to promote the formation of hydrates, forming secondary energy storage. This process can further increase the energy storage density and can also concentrate the seawater through hydrate formation to form brine, which can be further industrially purified or discharged.

[0032] 3. Hydrate decomposition and energy release module 4: During the peak period of electricity demand, by adjusting the temperature and pressure conditions, the hydrates decompose in the hydrate decomposition tank 7, releasing high-pressure gas. This high-pressure gas is then guided to the expander or turbine 13 to drive the generator to generate electricity. The fresh water generated during the hydrate decomposition process can be directly utilized, providing a valuable fresh water resource, especially suitable for freshwater-deficient areas such as islands, coastal areas, and ocean-going ships. A large amount of cold energy is released during the hydrate decomposition process, and this cold energy pre-cools the seawater entering the system through the heat exchanger 11, reducing the initial temperature of the seawater and improving the efficiency of the subsequent hydrate formation process.

[0033] 4. Power generation module 5: Utilize the high-pressure gas generated after hydrate decomposition to drive the expander or turbine 13 to generate electricity. This process not only realizes the effective conversion of energy but also significantly improves the overall energy efficiency of the system. By optimizing the control strategy, ensure that the power generation process matches the electricity demand to minimize energy loss.

[0034] 5. Cold energy recovery module 6: The low-temperature cold energy generated during the hydrate decomposition process pre-cools the seawater through the heat exchanger 11, generates fresh water and utilizes it as a fresh water resource. The cold water flowing out of the heat exchanger 11 circulates into the hydrate formation kettle to provide pre-cooled water for the subsequent hydrate formation and energy storage, further improving the energy utilization efficiency of the system.

[0035] The present invention innovatively combines gas compression energy storage and hydrate phase change technology, and proposes an efficient, environmentally friendly and sustainable integrated system, providing a new solution for solving energy storage, power generation and seawater desalination. This system is particularly suitable for complex environments that require efficient energy management and fresh water supply, and has broad application prospects.

[0036] The object of the present invention is achieved by the following technical solutions:

[0037] Utilize wind energy, photovoltaic power generation, excess electricity or waste electricity to drive the air compressor 2, compress the low-pressure hydrate-forming gas to a high-pressure state, and transport it to the hydrate formation tank 5. Stirring can be added inside the hydrate formation tank 5. Seawater is sprayed downward from the upper part of the hydrate formation tank. An appropriate amount of hydrate promoter or nano-SiO2 particles, etc. can be added to the seawater to promote hydrate formation. Under suitable temperature and pressure conditions, guide the high-pressure gas to contact the seawater, so that the high-pressure gas and seawater form hydrates. The formation of hydrates can reduce the pressure of the gas, thereby completing the secondary storage of energy, and discharging the concentrated salt solution.

[0038] When the peak of electricity demand arrives, based on the principle that hydrate decomposition is an endothermic process and can release gas, the hydrate is decompressed and decomposed by exhausting. The gas stored in the hydrate is released in the hydrate decomposition tank 7. The released gas does work through the expander or turbine 13 to drive the motor to generate electricity, realizing energy release. After the gas is released, it is recycled to the gas storage tank 14 again. When there is green electricity, excess electricity or waste electricity, it is compressed by the compressor 2 again and used as the formation gas required for the next round of hydrate formation.

[0039] In addition, the fresh water generated during the process of hydrate decomposition can be directly used as fresh water resources. The cold energy generated by hydrate decomposition is mainly concentrated in the fresh water generated after decomposition. Use the heat exchanger 11 to pre-cool the fresh seawater with the cold energy generated by hydrate decomposition, and then introduce the cooled seawater into the seawater storage tank 15 as the water required for the next round of hydrate formation.

[0040] The described system is a seawater desalination and power generation system for gas compression-hydrate secondary energy storage. Through this system, high-density energy storage and seawater desalination can be achieved. The gas released by the decomposed hydrate can realize the conversion of electrical energy, and the fresh water generated by decomposition can be used as fresh water resources.

[0041] Embodiment 2:

[0042] This embodiment details the specific operation steps of a comprehensive system for gas compression-hydrate energy storage-seawater desalination-power generation driven by wind energy, photovoltaic power generation, excess electricity or waste electricity. This system not only realizes efficient energy storage but also provides a sustainable fresh water supply.

[0043] Specific operation steps

[0044] 1. Gas compression energy storage stage: Utilize the green electricity generated by the wind turbine or photovoltaic panel, or the low-cost electricity in the power grid to drive the compressor 2 to compress the low-pressure hydrate-forming gas (methane, ethane, propane, N2, CO2, etc.) to a high-pressure state.

[0045] 2. Hydrate formation energy storage stage: The compressed high-pressure hydrate formation gas is discharged through outlet 3 and transported to the hydrate formation tank 5. An appropriate amount of hydrate promoter or nano-SiO2 particles is added into the hydrate formation tank 5, and pre-cooled seawater is injected from inlet 4. The seawater is sprayed downward from the top of the tank, guiding the high-pressure gas to come into full contact with the seawater under suitable temperature and pressure conditions, promoting the rapid formation of hydrates. The stirring device ensures the uniform mixing of the gas and the seawater, improving the reaction rate. The formed hydrates reduce the pressure of the gas, completing the energy storage. The concentrated seawater is discharged through outlet 6 for subsequent treatment or discharge.

[0046] 3. Energy release stage: When the peak period of electricity demand arrives, the hydrates are decomposed by adjusting the pressure in the hydrate decomposition tank 7. Since the decomposition process is an endothermic process, high-pressure gas is released and cold energy is generated. The exhaust device is used to guide these high-pressure gases to be discharged from outlet 8 into the expander or turbine 13, driving the generator to generate electric energy. After the released gas passes through the expander or turbine 13, it is recycled to the gas storage tank again. When there is green electricity, excess electricity or waste electricity, the dry gas dried by the dryer 16 is recompressed by the compressor 2 again and used as the formation gas required for the next round of hydrate formation.

[0047] 4. Cold energy recovery: The cold energy generated during the hydrate decomposition process is mainly concentrated in the fresh water produced after decomposition. The fresh water is discharged from outlet 9, and the heat exchanger 11 is used to pre-cool the fresh seawater with this cold water, reducing its initial temperature. The fresh seawater discharged through inlet 10 is pre-cooled and then introduced into the cooling seawater storage tank 15 through outlet 12 for heat preservation and used as the water required for the next round of hydrate formation. The fresh water generated during the hydrate decomposition process can be directly used as fresh water resources, especially suitable for areas with scarce fresh water such as islands, coastal areas and ocean-going ships.

[0048] Implementation effect

[0049] Through the above steps, the present invention achieves the following goals:

[0050] Efficient energy storage: High-efficiency energy storage is achieved through the gas compression-hydrate formation secondary energy storage mode, which has a higher energy storage density compared with traditional air compression energy storage.

[0051] Environmental protection and sustainability: Using wind energy, photovoltaic power generation or low-cost electricity for air compression energy storage reduces the dependence on fossil fuels and conforms to the development trend of green and low-carbon.

[0052] Multi-functional application: It can not only generate electricity, but also simultaneously achieve seawater desalination, providing valuable fresh water resources, especially suitable for areas with scarce fresh water such as islands, coastal areas and ocean-going ships.

[0053] Cost-effective: Since the cold energy recovery and recycling generated by hydrate decomposition are fully considered in the system design, the operating cost is reduced and the economic benefit is improved.

[0054] Adapt to extreme environments: The system design is applicable to special application scenarios such as islands, coastal areas, ocean-going ships and offshore oil and gas platforms, etc., and has strong environmental adaptability and stability.

[0055] The attached drawings in the specification of this application are only schematic. The sizes and shapes of the components shown are not actually limited, but only a schematic representation. In the actual implementation process, the components can be reasonably configured and adjusted according to specific requirements and actual situations.

[0056] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0057] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A seawater desalination and power generation system using gas compression-hydrate secondary energy storage, characterized in that ,include: The gas compression energy storage module (2) is used to drive an air compressor through green electricity, waste electricity or surplus electricity (1) to compress low-pressure gas to high pressure for primary energy storage; The hydrate forming energy storage module (3) is used to receive high-pressure gas and react with seawater to form hydrates, thereby realizing secondary energy storage; The hydrate decomposition and energy generation module (4) is used to decompose hydrates during the peak period of electricity demand, release gas, and produce low-temperature fresh water; The power generation module (6) utilizes the gas released by the decomposition of the hydrate to drive an expander or a turbine to generate electricity, thereby improving energy utilization efficiency; The cold energy recovery module (5) uses a heat exchanger to pre-cool fresh seawater by producing low-temperature fresh water from the heat absorption of hydrate decomposition, thereby enhancing energy utilization efficiency and increasing the subsequent hydrate formation rate, while obtaining fresh water resources.

2. A seawater desalination and power generation system utilizing gas compression-hydrate secondary energy storage according to claim 1, characterized in that: The gas compression energy storage module (2) can be driven by wind energy, photovoltaic power or surplus power from a power grid, so as to improve the utilization rate of renewable energy in the system.

3. The seawater desalination and power generation system using gas compression-hydrate secondary energy storage according to claim 1 is characterized in that: The hydrate forming energy storage module (3) comprises a stirring device for optimizing the hydrate generation rate and improving the overall energy storage efficiency.

4. The seawater desalination and power generation system using gas compression-hydrate secondary energy storage according to claim 1 is characterized in that: The power generation module (5) utilizes the gas released by the hydrate decomposition and energy exponential module (4) to drive an expander or a turbine to generate electricity, thereby improving energy utilization.

5. The seawater desalination and power generation system using gas compression-hydrate secondary energy storage according to claim 1 is characterized in that: The cold energy recovery module (6) comprises a heat exchanger, which is used to circulate the cold energy generated by the decomposition of low-temperature hydrates, thereby improving the thermal energy management capability of the system.

6. The seawater desalination and power generation system using gas compression-hydrate secondary energy storage according to claim 1 is characterized in that: The hydrate-forming gas in the hydrate generation module may be (hydrate-forming gas such as methane, ethane, propane, carbon dioxide, hydrogen, nitrogen, etc.).

7. The seawater desalination and power generation system using gas compression-hydrate secondary energy storage according to claim 1 is characterized in that: Hydrate promoters (cyclopentane, tetrahydrofuran, SDS, etc.) and nanoparticles may be added to the hydrate forming energy storage module (3) to accelerate hydrate formation, thereby increasing energy storage efficiency.

8. The seawater desalination and power generation system using gas compression-hydrate secondary energy storage according to claim 1 is characterized in that: Based on this system, energy storage and conversion can be carried out at the same time, usable fresh water resources can be generated, energy utilization efficiency can be improved, and a fresh water supply solution can be provided.

9. A seawater desalination and power generation system using gas compression-hydrate secondary energy storage according to claims 1-8, characterized in that: The system is suitable for environments such as islands, coastal areas, ocean-going ships and offshore oil and gas platforms, and provides efficient, environmentally friendly and sustainable energy and fresh water supply.

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