A high salinity water desalination device with compressed air energy storage system

Abstract

The application provides a high-salinity water desalination device with a compressed air energy storage system, and belongs to the field of desalination and water treatment. The device comprises: a compressor unit for compressing external air to a high-pressure state; a heat storage and heat exchange system for heat exchange treatment of the high-pressure air; an air storage chamber for storing the high-pressure air after heat exchange treatment; a heat release and heat exchange system for preheating the high-pressure air; an expander unit for work using the preheated high-pressure air and for power generation of an engine; an evaporation tank for flash evaporation of hot water generated after heat exchange treatment of the high-pressure air and for steam generation; and a multi-stage evaporation device for high-salinity water desalination using steam as a heat source and for fresh water generation. The application can use the excess compression heat generated by the compressor unit as working steam of the multi-stage evaporation device, thereby improving the energy efficiency utilization rate of the compressor unit and reducing the cost of high-salinity water desalination of the multi-stage evaporation device.

Description

Technical Field

[0001] This invention relates to the field of desalination and water treatment, and more specifically to a high-salinity desalination device with a compressed air energy storage system. Background Technology

[0002] The rapid development of new energy sources in my country presents unprecedented challenges to the safe and stable operation of the power system due to their randomness, volatility, and intermittency. Compressed air energy storage (CASS), as one of the new energy storage technologies, boasts advantages such as being environmentally friendly, having a high safety factor, and offering rapid response. It is a feasible large-scale energy storage technology that will play a crucial role in various application scenarios, including peak shaving, frequency regulation, and load tracking, providing rapid response and precise control. CASS technology utilizes surplus grid electricity or new energy power generation to drive compressor units during off-peak hours, compressing air to a high-pressure state and storing it in a high-pressure air storage chamber, thus converting electrical energy into the internal energy of the air. During peak hours, the preheated high-pressure air enters a turbine expander to drive a generator, generating electricity that is then fed back to the grid, releasing the energy. As a feasible large-scale energy storage technology, CASS has significant commercial development potential and application value, representing an important solution for the comprehensive utilization of clean and conventional energy sources.

[0003] With the increasing scarcity of water resources and the growing demand for water, high-salinity desalination is playing an increasingly important role in water resource utilization. Desalinated water, as a crucial source of high-quality incremental water, serves as an important supplement and strategic reserve for water resources, and is of great significance for ensuring water security. In recent years, high-salinity desalination technologies have matured both domestically and internationally, and the high-salinity desalination industry has grown significantly. Thermal and membrane methods are currently the mainstream high-salinity desalination processes in China, with low-temperature multi-effect distillation technology gradually developing and becoming dominant.

[0004] In the process of using low-temperature multi-effect distillation technology, compressed air energy storage system is used to generate compression heat to enable the flash tank to work. However, excess compression heat will be discharged, resulting in low energy efficiency and increasing the cost of seawater desalination. Summary of the Invention

[0005] The purpose of this invention is to provide a high-salinity desalination device with a compressed air energy storage system to solve the problem that in the process of using low-temperature multi-effect distillation technology, the compressed air energy storage system generates compression heat to enable the flash tank to work, but the excess compression heat is discharged, resulting in low energy efficiency and increased cost of seawater desalination.

[0006] To achieve the above objectives, embodiments of the present invention provide a high-salinity desalination device with a compressed air energy storage system, comprising:

[0007] The compressor unit is used to compress outside air to a high pressure state;

[0008] The heat storage and heat exchange system is connected to the compressor unit and performs heat exchange treatment on the air compressed to a high pressure state;

[0009] The air storage chamber, connected to the heat storage and heat exchange system, is used to store high-pressure air that has undergone heat exchange treatment;

[0010] A heat release and heat exchange system, connected to the gas storage chamber, is used to preheat high-pressure air;

[0011] The expander unit is connected to the heat release and heat exchange system, uses preheated high-pressure air to do work, and enables the engine connected to the expander unit to generate electricity.

[0012] An evaporator, connected to the heat storage and heat exchange system, is used to flash evaporate the hot water generated after the heat storage and heat exchange system has processed the compressed air to a high pressure state, and to generate steam.

[0013] A multi-stage evaporation device, connected to the evaporation tank, uses steam as a heat source to desalinate brine and produce fresh water.

[0014] Optionally, it includes: a cold water tank and a hot water tank, wherein the inlet of the cold water tank is connected to the heat release and heat exchange system, and its outlet is connected to the heat storage and heat exchange system; the inlet of the hot water tank is connected to the heat storage and heat exchange system, and its outlet is connected to the heat release and heat exchange system.

[0015] Optionally, the compressor unit includes multiple compressors, and the heat storage and heat exchange system includes multiple gas-water heat exchangers corresponding to the number of compressors. The multiple compressors are connected in series through multiple gas-water heat exchangers. The air outlet of the previous stage compressor is connected to the air inlet of the next stage compressor through a corresponding gas-water heat exchanger. The air inlet of the primary compressor is used to draw in air, and the air outlet of the final stage compressor is connected to the air storage chamber through a corresponding gas-water heat exchanger.

[0016] Optionally, the expander unit includes multiple expanders connected in series, with the air inlet of the initial expander connected to the heat release and heat exchange system, and the air outlet of the final expander used to discharge air.

[0017] Optionally, the multi-stage evaporation device includes multiple horizontal tube falling film evaporators connected in sequence on the same horizontal plane, wherein the air inlet end of the initial horizontal tube falling film evaporator is connected to the flash tank.

[0018] Optionally, the horizontal tube falling film evaporator is used for:

[0019] The brine injected into the horizontal tube falling film evaporator is desalinated by steam evaporation to produce fresh water.

[0020] Optionally, the horizontal tube falling film evaporator at the end is connected to a concentrated brine pump for discharging concentrated brine produced after the brine is desalinated by the horizontal tube falling film evaporator, a freshwater pump for discharging freshwater, and a condenser.

[0021] Optionally, the initial end of the horizontal tube falling film evaporator is provided with a vacuum system, which is used to enable the horizontal tube falling film evaporator to operate in a vacuum state. The vacuum device is one of a steam jet ejector, a water ring vacuum pump, or a combination of a steam jet ejector and a water ring vacuum pump.

[0022] Optionally, the internal pressure of the horizontal tube falling film evaporator is controlled below 70 kPa, and the temperature of the high-salt water inside is controlled below 90°C.

[0023] Optionally, the horizontal tube falling film evaporator at the initial end is provided with a backup steam source port, wherein the backup steam source is industrial steam.

[0024] In this embodiment of the invention, the high-pressure air generated by the compressor unit is recovered and reused, which greatly improves the efficiency of the compressor unit. By applying this patented technology, after the gas storage chamber is full, the high-pressure air can be discharged to the heat release and heat exchange system, and then the generator is driven by the expander unit to generate electricity, realizing the rational utilization of the high-pressure air. The evaporator is used to flash evaporate the hot water that has passed through the heat release and heat exchange system. The generated steam drives the multi-stage evaporation device to produce high-quality fresh water, reducing the energy cost of desalination of water with high salt content such as high salinity. On the other hand, the heating steam of the multi-stage evaporation device of this patent uses flash steam as the steam source, and general industrial steam can be used as a backup steam source, improving the effective utilization rate of the multi-stage evaporation device and improving the reliability of continuous operation of the equipment. Attached Figure Description

[0025] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0026] Figure 1 This is a schematic diagram of the structure of a high-salinity desalination device with a compressed air energy storage system provided in an embodiment of the present invention.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. Evaporator; 2. Compressor unit; 3. Heat storage and heat exchange system;

[0029] 4. Heat release and heat exchange system; 5. Expander unit; 6. Gas storage chamber;

[0030] 7. Hot water tank; 8. Cold water tank; 9. Fresh water pump; 10. Condenser;

[0031] 11. Concentrated brine pump; 12. Horizontal tube falling film evaporator. Detailed Implementation

[0032] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this application.

[0034] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0035] Please refer to Figure 1 , Figure 1 This is a schematic diagram of a high-salinity desalination device with a compressed air energy storage system provided in an embodiment of the present invention. The device includes: a compressor unit 2 for compressing external air to a high-pressure state; a heat storage and heat exchange system 3 connected to the compressor unit 2 for heat exchange treatment of the compressed air to a high-pressure state; a gas storage chamber 6 connected to the heat storage and heat exchange system 3 for storing the heat-treated high-pressure air; a heat release and heat exchange system 4 connected to the gas storage chamber 6 for preheating the high-pressure air; an expander unit 5 connected to the heat release and heat exchange system 4 for using the preheated high-pressure air to perform work and for generating electricity using an engine connected to the expander unit 5; an evaporator tank 1 connected to the heat storage and heat exchange system 3 for flash evaporation of the hot water generated after the heat storage and heat exchange system 3 treats the compressed air to a high-pressure state, and for generating steam; and a multi-stage evaporation device connected to the evaporator tank 1 for using steam as a heat source to desalinate brine and produce fresh water.

[0036] Specifically, using this device for seawater desalination can reduce desalination costs by about 50%, improve the overall efficiency of compressed air energy storage and seawater desalination systems, and has a promising future market prospect. At the same time, this design overcomes the frequent start-stop of conventional compression systems, which can improve the utilization rate of compressor units and extend equipment life.

[0037] In this embodiment, the high-pressure air generated by the compressor unit 2 is recovered and reused, which greatly improves the efficiency of the compressor unit 2. By applying this patented technology, after the gas storage chamber 6 is full, the high-pressure air can be discharged to the heat release and heat exchange system 4, and then the generator is driven by the expander unit 5 to generate electricity, realizing the rational utilization of the high-pressure air. The evaporator 1 is used to flash evaporate the hot water that has passed through the heat release and heat exchange system 4. The generated steam drives the multi-stage evaporation device and produces high-quality fresh water, reducing the energy cost of desalination of water with high salt content such as high brine. On the other hand, the heating steam of the multi-stage evaporation device of this patent uses flash steam as the steam source, and general industrial steam can be used as a backup steam source, improving the effective utilization rate of the multi-stage evaporation device and improving the reliability of continuous operation of the equipment.

[0038] Optionally, the above-mentioned device further includes: a cold water tank 8 and a hot water tank 7, wherein the inlet of the cold water tank 8 is connected to the heat release and heat exchange system 4, and its outlet is connected to the heat storage and heat exchange system 3; the inlet of the hot water tank 7 is connected to the heat storage and heat exchange system 3, and its outlet is connected to the heat release and heat exchange system 4.

[0039] In this embodiment, the heat storage and heat exchange system 3 is designed to require that the cooling water temperature not only meets the inlet parameters of the compressed evaporator 1, but also the inlet hot water temperature of the evaporator 1; at the same time, it must maintain the water volume balance between the cold water tank 8 and the hot water tank 7. Under different operating conditions, it needs to work with the MVR steam compressor to achieve the recycling of heat. Alternatively, the product water from the multi-stage evaporation device can be used as makeup water for the cold water tank 8 to maintain the system water volume balance.

[0040] Optionally, the compressor unit 2 includes multiple compressors, and the heat storage and heat exchange system 3 includes multiple gas-water heat exchangers corresponding to the number of compressors. The multiple compressors are connected in series through multiple gas-water heat exchangers. The air outlet of the first-stage compressor is connected to the air inlet of the next-stage compressor through the corresponding gas-water heat exchanger. The air inlet of the primary compressor is used to draw in air, and the air outlet of the final-stage compressor is connected to the air storage chamber 6 through the corresponding gas-water heat exchanger.

[0041] In this embodiment, the high-temperature and high-pressure air generated by each compressor is transformed into low-temperature and high-pressure air after passing through the gas-water heat exchanger and stored in the air storage chamber 6. The electrical energy used to drive the compressor in this design is off-peak electricity, which has the characteristics of low cost.

[0042] Optionally, the expander unit 5 includes multiple expanders connected in series. The air inlet of the initial expander is connected to the heat release and heat exchange system 4, and the air outlet of the final expander is used to discharge air.

[0043] In this embodiment, when the gas storage chamber 6 is full, the excess low-temperature high-pressure gas is transformed into high-temperature high-pressure gas through the heat release and heat exchange system 4, which drives the expander to work. The expander drives the generator to work and generates electricity for transmission, thereby achieving the purpose of rational energy utilization.

[0044] Optionally, the multi-stage evaporation device includes multiple horizontal tube falling film evaporators 12 connected in sequence on the same horizontal plane, wherein the air inlet end of the initial horizontal tube falling film evaporator 12 is connected to the flash tank.

[0045] Optionally, the horizontal tube falling film evaporator 12 is used to evaporate the brine injected into the horizontal tube falling film evaporator 12 using steam, so as to desalinate the injected brine and produce fresh water.

[0046] Each horizontal tube falling film evaporator 12 is called an "effect," and its structure is similar to a shell-and-tube heat exchanger with horizontally arranged heat exchange tubes. The horizontal tube falling film evaporator 12 contains heat exchange tubes, where heating steam condenses and releases heat. High-salt water is sprayed onto the outside of the heat exchange tubes, absorbing heat and evaporating into steam. "Multi-effect" refers to multiple horizontal tube falling film evaporators 12 connected in series. The steam evaporated in one effect is used as heating steam for the next effect, and so on, until the fresh water produced by each horizontal tube falling film evaporator 12 is collected and utilized. The more effects there are, the more evaporations occur, and the pressure gradually decreases in each effect. Therefore, the amount of fresh water produced from the same steam input is greater, meaning that low-temperature multi-effect distillation can utilize low-grade waste heat.

[0047] In one embodiment, steam with a pressure of not less than 25 kPa and hot water with a temperature of not less than 90°C can both be used as heat sources for the MED.

[0048] Optionally, the horizontal tube falling film evaporator 12 at the end is connected to a concentrated brine pump 11 for discharging concentrated brine produced after the brine is desalinated by the horizontal tube falling film evaporator 12, a fresh water pump 9 for discharging fresh water, and a condenser 10.

[0049] Optionally, the initial end of the horizontal tube falling film evaporator 12 is provided with a vacuum system. The vacuum system is used to make the horizontal tube falling film evaporator 12 work in a vacuum state. The vacuum device is one of a steam jet ejector, a water ring vacuum pump, or a combination of a steam jet ejector and a water ring vacuum pump.

[0050] Optionally, the internal pressure of the horizontal tube falling film evaporator 12 is controlled below 70 kPa, and the temperature of the high brine inside is controlled below 90°C.

[0051] Optionally, the horizontal tube falling film evaporator 12 at the initial end is provided with a backup steam source port, and the backup steam source is industrial steam.

[0052] In one embodiment, high-pressure industrial steam can be used as a backup steam source for the multi-stage evaporator. The multi-stage evaporator is equipped with two relatively independent interfaces for steam sources. Depending on the different steam parameters, the diameter of the steam interface leading out from evaporator 1 is 5-10 times the diameter of the industrial steam interface, reaching 2000-3000 mm. The two pipelines are switched by valves. When mixed steam is required, the flow rate of different steam sources is matched by controlling the opening of the regulating valve, so that the amount of steam entering the multi-stage evaporator meets the design requirements.

[0053] In this embodiment, by providing a backup steam source port on the horizontal tube falling film evaporator 12 at the initial end, the effective utilization rate of the multi-stage evaporation device and the reliability of continuous operation of the equipment can be improved.

[0054] The term "substantially constitutes" used to describe a combination should include the identified element, component, part, or step, as well as other elements, components, parts, or steps that do not substantially affect the essential novel features of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term "may" herein is intended to indicate that any described attribute included by "may" is optional. Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply exclusion of other elements, components, parts, or steps.

[0055] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A high-salinity desalination device with a compressed air energy storage system, characterized in that, include: The compressor unit is used to compress outside air to a high pressure state; The heat storage and heat exchange system is connected to the compressor unit and performs heat exchange treatment on the air compressed to a high pressure state; The air storage chamber, connected to the heat storage and heat exchange system, is used to store high-pressure air that has undergone heat exchange treatment; A heat release and heat exchange system, connected to the gas storage chamber, is used to preheat high-pressure air; The expander unit is connected to the heat release and heat exchange system, uses preheated high-pressure air to do work, and enables the engine connected to the expander unit to generate electricity. An evaporator, connected to the heat storage and heat exchange system, is used to flash evaporate the hot water generated after the heat storage and heat exchange system has processed the compressed air to a high pressure state, and to generate steam. A multi-stage evaporation device is connected to the evaporation tank and uses steam as a heat source to desalinate brine and produce fresh water. The cold water tank and the hot water tank are provided. The inlet of the cold water tank is connected to the heat release and heat exchange system, and its outlet is connected to the heat storage and heat exchange system. The inlet of the hot water tank is connected to the heat storage and heat exchange system, and its outlet is connected to the heat release and heat exchange system. The heat storage and heat exchange system heats the air compressed to a high pressure state to produce hot water with a temperature that meets the inlet hot water temperature of the evaporator and maintains the balance of water volume between the cold water tank and the hot water tank. It also works with the MVR steam compressor to achieve heat recycling under different operating conditions.

2. The high-salinity desalination device with a compressed air energy storage system according to claim 1, characterized in that, The compressor unit includes multiple compressors, and the heat storage and heat exchange system includes multiple gas-water heat exchangers corresponding to the number of compressors. The multiple compressors are connected in series through multiple gas-water heat exchangers. The air outlet of the first-stage compressor is connected to the air inlet of the next-stage compressor through a corresponding gas-water heat exchanger. The air inlet of the primary compressor is used to draw in air, and the air outlet of the final-stage compressor is connected to the air storage chamber through a corresponding gas-water heat exchanger.

3. The high-salinity desalination device with a compressed air energy storage system according to claim 1, characterized in that, The expander unit includes multiple expanders connected in series. The air inlet of the initial expander is connected to the heat release and heat exchange system, and the air outlet of the final expander is used to discharge air.

4. The high-salinity desalination device with a compressed air energy storage system according to claim 1, characterized in that, The multi-stage evaporation device includes multiple horizontal tube falling film evaporators connected in sequence on the same horizontal plane, wherein the air inlet end of the initial horizontal tube falling film evaporator is connected to the evaporation tank.

5. The high-salinity desalination device with a compressed air energy storage system according to claim 4, characterized in that, The horizontal tube falling film evaporator is used to evaporate the brine injected into the horizontal tube falling film evaporator using steam, so as to desalinate the injected brine and produce fresh water.

6. The high-salinity desalination device with a compressed air energy storage system according to claim 5, characterized in that, The horizontal tube falling film evaporator at the end is connected to a concentrated brine pump for discharging concentrated brine produced after the brine is desalinated by the horizontal tube falling film evaporator, a freshwater pump for discharging freshwater, and a condenser.

7. The high-salinity desalination device with a compressed air energy storage system according to claim 4, characterized in that, The horizontal tube falling film evaporator is equipped with a vacuum system at its initial end. The vacuum system is used to enable the horizontal tube falling film evaporator to operate in a vacuum state. The vacuum system is one of a vapor ejector, a water ring vacuum pump, or a combination of a vapor ejector and a water ring vacuum pump.

8. The high-salinity desalination device with a compressed air energy storage system according to claim 4, characterized in that, The internal pressure of the horizontal tube falling film evaporator is controlled below 70 kPa, and the temperature of the high-salt water inside is controlled below 90°C.

9. A high-salinity desalination device with a compressed air energy storage system according to any one of claims 4-8, characterized in that, The horizontal tube falling film evaporator at the initial end is equipped with a backup steam source port, and the backup steam source is industrial steam.

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