Water resource comprehensive utilization system based on fishing and light complementation and working method of water resource comprehensive utilization system

Abstract

The invention relates to a water resource comprehensive utilization system based on fishing and light complementation and a working method thereof, and belongs to the field of comprehensive utilization of renewable energy sources and seawater resources. The system comprises a fishing light complementation module, a seawater desalination module, an electrolytic oxygen production and hydrogen production and storage module, a fishery oxygen supply module, a spray cleaning and water resource recovery module, a membrane assembly self-cleaning module and an automatic monitoring and control module. The photovoltaic direct current and the solar heat collector cooperatively drive the membrane distillation device to carry out low-temperature desalination on seawater; one part of the distilled water enters an electrolytic tank to produce hydrogen / oxygen and store the hydrogen / oxygen respectively, oxygen is supplied to the fishery in situ through an aeration disc, and hydrogen is stored as a green hydrogen product; the other part of distilled water and collected rainwater are jointly used for automatic spraying and cleaning of a photovoltaic module and a membrane module, cleaning water is subjected to precipitation-microfiltration and then flows back to a membrane distillation system, and online pickling recovery of membrane pollution is achieved. The desalination and electrolysis energy consumption is remarkably reduced, and the photovoltaic and membrane distillation operation stability is improved.

Description

Technical Field

[0001] This invention relates to the interdisciplinary field of renewable energy and comprehensive utilization of seawater resources, specifically to a comprehensive water resource utilization system based on fishery-solar integration and its working method. Background Technology

[0002] The solar-aquaculture complementary model has been rapidly promoted in nearshore aquaculture areas, but its function is still limited to the single superposition stage of "generating electricity on the water surface and raising fish underwater". The contradiction between photovoltaic temperature rise and biological oxygen consumption is prominent. At the same time, coastal islands and deep-sea aquaculture platforms have long faced the "three shortages" - lack of fresh water, lack of green electricity, and lack of oxygen.

[0003] Patent documents CN116575038A and CN116463656A disclose methods for seawater desalination and electrolysis hydrogen production, but both suffer from high evaporation temperatures and high energy consumption in seawater desalination. CN117509793A discloses a sustainable solar-driven hydrogen production system and its control method, which discloses a photothermal-driven membrane distillation method for seawater desalination followed by electrolysis hydrogen production. However, this method does not consider the membrane fouling problem caused by long-term operation of membrane distillation, the pollution problem of photovoltaic modules leading to a decrease in power generation efficiency, and the fact that the power supply modules for photothermal-driven membrane distillation seawater desalination and photovoltaic power generation for electrolysis hydrogen production are separate, resulting in low system stability.

[0004] In summary, existing technologies have failed to integrate "fishing, solar power, water, hydrogen, and oxygen" into a single energy-matter cycle, resulting in low system energy efficiency, high operating costs, and incomplete elimination of carbon emissions. Furthermore, they have not considered the system's cleaning issues. Therefore, there is an urgent need for a zero-carbon integrated system that can directly couple desalination, energy storage, oxygen supply, and cleaning at sea. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a comprehensive water resource utilization system based on fishery-solar integration and its operating method to solve the aforementioned problems.

[0006] This invention provides the following technical solution: A comprehensive water resource utilization system based on fishery-solar integration includes a fishery-solar integration module, a seawater desalination module, an electrolysis oxygen-to-hydrogen production and storage module, a fish farm oxygen supply module, a spray cleaning and water resource recovery module, and an automatic monitoring and control module. The fishery-solar integration module includes a coastal fish farm and a photovoltaic power generation system erected above the fish farm, with the photovoltaic power generation system supported by a corrosion-resistant steel frame. The seawater desalination module includes, in sequence, a microfiltration filter, a hot water exchange tank, a membrane distillation device, and a distilled water tank. The inlet of the microfiltration filter is connected to the coastal fish farm and clean water and rainwater collection tanks, respectively. A solar collector is installed above the hot water exchange tank, and an electric heater is also installed inside. The membrane distillation device includes an inlet side, a porous hydrophobic membrane, and an outlet side, with the porous hydrophobic membrane positioned between the inlet and outlet sides to separate the inlet and outlet water. The system comprises: a water-side and an outlet-side system; an electrolysis oxygen-to-hydrogen production and storage module, wherein the inlet of the electrolysis oxygen-to-hydrogen production and storage module is connected to the first outlet of the distilled water tank for electrolysis of distilled water to obtain oxygen and hydrogen, which are then stored separately; a fish farm oxygen supply module, wherein the inlet of the fish farm oxygen supply module is connected to the oxygen storage device of the electrolysis oxygen-to-hydrogen production and storage module, and the outlet is located in the fish farm water body; a spray cleaning and water resource recovery module, wherein the spray cleaning and water resource recovery module includes a spray water tank, a spray system, a clean water and rainwater collection tank, and a clean water and rainwater collection container, wherein the inlet of the spray water tank is connected to the second outlet of the distilled water tank, the spray system is located above the photovoltaic power generation system, the clean water and rainwater collection tank is located below the photovoltaic modules and connected to the clean water and rainwater collection container; and an automatic monitoring and control module, which collects unified data on the operating parameters of each module and monitors and controls them in real time.

[0007] Furthermore, the membrane distillation device is a direct contact type, air gap type, scavenging type, or vacuum type membrane distillation configuration; the porous hydrophobic membrane material is PVDF or PTFE, and the membrane module of the porous hydrophobic membrane is generally a flat sheet membrane or hollow fiber membrane, etc., with an average pore size of 0.1 to 5.0 µm; the inlet water temperature is 40 ℃ to 95 ℃, and the outlet water temperature is -2 ℃ to 30 ℃.

[0008] Furthermore, the feed liquid of the membrane distillation device and the distilled water in the distillation tank are both circulated separately; wherein, the distilled water circulation pipe is fitted with a seawater condenser pipe to condense the water vapor that evaporates from the inlet side to the outlet side into distilled water, thereby stabilizing the operating temperature of the outlet side of the membrane distillation device.

[0009] Furthermore, multiple heat exchange tanks can be set up to heat the filtered seawater to different temperatures for use in multi-stage membrane distillation, thereby improving thermal efficiency.

[0010] Furthermore, the electrolytic oxygen-to-hydrogen production and storage module includes an anode chamber, an ion exchange membrane, a cathode chamber, a DC power supply, an anode electrode plate, a cathode electrode plate, a hydrogen scrubber, a hydrogen dryer, a hydrogen storage device, an oxygen scrubber, an oxygen dryer, and an oxygen storage device. The DC power supply is connected to a photovoltaic power generation system, with its positive terminal connected to the anode electrode plate in the anode chamber and its negative terminal connected to the cathode electrode plate in the cathode chamber. The ion exchange membrane separates the anode chamber and the cathode chamber. The oxygen produced in the anode chamber is passed through the oxygen scrubber and the oxygen dryer before being stored in the oxygen storage device. The hydrogen produced in the cathode chamber is passed through the hydrogen scrubber and the hydrogen dryer. The gas is then passed into a hydrogen storage device for storage. The purity of the separated oxygen and hydrogen can generally reach over 99.9%. After being treated by a scrubber and dryer, they can be directly used in industrial and experimental fields. The electrolytic oxygen and hydrogen production and storage module adopts a proton exchange membrane or anion exchange membrane electrolytic cell and is arranged in an array-type modular configuration. The DC power supply of the electrolytic oxygen and hydrogen production and storage module is connected to a photovoltaic power generation system. The membrane module of the ion exchange membrane is generally a flat sheet membrane or a hollow fiber membrane. When the ion exchange membrane is a proton exchange membrane, the distilled water inlet pipe is connected to the anode chamber; when the ion exchange membrane is an anion exchange membrane, the distilled water inlet pipe is connected to the cathode chamber.

[0011] Furthermore, the fish farm oxygen supply module includes an oxygen pump, an aeration plate, an electric flow regulating valve, and an oxygen content sensor; the oxygen pump delivers oxygen from the oxygen storage device to the aeration plate, with the oxygen content sensor, the electric flow regulating valve, and the aeration plate connected in sequence; the aeration direction of the aeration plate can be automatically adjusted 360°; the oxygen content sensor and the electric flow regulating valve are mounted in a corrosion-resistant steel bracket to prevent corrosion from seawater immersion.

[0012] Furthermore, the spray system includes spray heads, spray pipes, sliders, and sliding tracks; the spray heads are evenly distributed on the spray pipes and are used to connect to distilled water in the spray water tank to clean the photovoltaic modules; the sliders are placed on the sliding tracks on both sides of the spray pipes; the sliding tracks are used to move the spray heads back and forth.

[0013] Furthermore, the angle between the water flow from the spray head and the plane where the photovoltaic panel is located is 30°~90°, and the spray pressure is automatically adjusted according to the pollution level fed back by the automatic monitoring and control module.

[0014] Furthermore, the system also includes a membrane module self-cleaning module, the inlet of which is connected to the outlet of the clean water and rainwater collection tank. The membrane fouling self-cleaning module is consistent with the apparatus and connections used in the seawater desalination process, except that the feed water is pretreated by sedimentation and microfiltration and is slightly acidic, consisting of clean water and rainwater (the acidic water effectively dissolves salts deposited on the porous hydrophobic membrane). In addition, the membrane distillation unit is cleaned after the membrane flux decreases to 25%–50%.

[0015] This invention also discloses a working method for a comprehensive water resource utilization system based on solar-fishery integration according to any one of the foregoing claims, comprising the following steps: S1: Seawater from the coastal fishing grounds is pumped into a microfiltration filter for pretreatment using a submersible pump, and then pumped into a hot water exchange tank for heating; S2: The pretreated seawater is heated to a stable temperature using a solar collector, while an electric heater is used for auxiliary heating to improve heating stability; S3: The heated pretreated seawater is fed into the inlet side of a membrane distillation device, where water vapor evaporates through the pores of a porous hydrophobic membrane to the outlet side. A seawater condenser is fitted over the distilled water circulation pipe on the outlet side for condensation, and both the inlet and outlet sides are maintained by circulation pumps; S4: The distilled water is pumped into an electrolytic cell for electrolysis to produce oxygen and hydrogen. During electrolysis, the distilled water tank... Water is pumped into the anode or cathode chamber to continuously replenish distilled water; the DC power generated by the photovoltaic power generation system powers the electrode plates on both sides for electrolysis, and the hydrogen and oxygen produced by electrolysis are sent into the storage device; S5: the oxygen in the oxygen storage device is transported to the aeration plate under each photovoltaic support through the oxygen delivery pipe driven by the oxygen pump for oxygen supply, and the oxygen content sensor monitors the oxygen content online and controls it in real time through the electric flow regulating valve; S6: when the photovoltaic power generation system detects that the power generation is unstable, the spray system starts to work; the water in the spray tank is pumped to each spray head through the spray pipe to clean each photovoltaic module. During the cleaning process, the slider moves back and forth on the sliding track, and the clean water produced by cleaning is collected into the clean water and rainwater collection tank after passing through the clean water and rainwater collection tank; S7: when the water production efficiency of the membrane distillation device drops to a certain level, the seawater intake stops, and the fresh water collected in the clean water and rainwater collection tank is sent to the heat exchange tank after sedimentation and microfiltration pretreatment. After being heated to a stable temperature, it is sent into the membrane distillation device to produce water while cleaning the fouled membrane.

[0016] The present invention has the following beneficial technical effects: This invention breaks away from the old paradigm of "simple superposition of solar and fishery energy", integrating photovoltaic power generation, solar thermal heat collection, membrane distillation desalination, electrolytic hydrogen / oxygen production, fishery oxygen supply and module / membrane self-cleaning into the same energy-matter closed loop, realizing the four-in-one synergy of "water surface power generation, water surface water production, underwater oxygen supply and system self-cleaning".

[0017] This invention utilizes a combination of photovoltaic waste heat and low-temperature photothermal energy to drive membrane distillation, eliminating the need for an external high-grade heat source. This reduces desalination energy consumption at the source, simultaneously absorbing surplus electricity and resolving the dual contradictions of "curtailed solar power" and "freshwater shortage." Furthermore, by pre-desalinating and then electrolyzing, this invention completely avoids the risks of anodic chlorine corrosion and cathode scaling associated with direct seawater electrolysis, ensuring a continuous and stable output of green hydrogen and oxygen. The electricity and heat required for electrolysis are supplied by the system's internal renewable energy source, eliminating the need for external energy replenishment.

[0018] This invention provides a method for injecting high-purity oxygen produced by electrolysis into aquaculture water in situ via a 360° adjustable aeration plate. This replaces traditional air aeration and liquid oxygen delivery, significantly improving dissolved oxygen efficiency and eliminating transportation and storage, thereby reducing fish farm operating costs.

[0019] This invention uses self-produced freshwater combined with rainwater as a cleaning medium for photovoltaic modules and membrane modules. It utilizes slightly acidic rainwater to dissolve salt scale online, realizing an internal cycle of "water production – water use – water return". The cleaning process is triggered by dual signals of power generation performance and membrane flux, avoiding manual intervention and external freshwater transportation, and ensuring long-term efficient operation of photovoltaic and membrane distillation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the water resource comprehensive utilization system based on fishery-solar complementary integration and its working method according to the present invention; Figure 2 This is a schematic diagram of the oxygen supply system of the fishery-solar hybrid system of the present invention; Figure 3 This is a schematic diagram of the self-cleaning photovoltaic module and the reuse of cleaning water and rainwater according to the present invention; Figure 4 This is a schematic diagram of the multi-stage membrane distillation seawater desalination and array-type electrolysis oxygen and hydrogen production system based on the complementary relationship between fishery and solar power.

[0021] The attached figures are labeled as follows: 1. Coastal fishing grounds; 2. Photovoltaic power generation system; 3. Microfiltration filter; 4. Hot water exchange tank; 4-1, No. 1 hot water exchange tank; 4-2, No. 2 hot water exchange tank; 4-3, No. 3 hot water exchange tank; 5. Solar collector; 6. Electric heater; 7. Membrane distillation device; 7-1, First-stage membrane distillation device; 7-2, Second-stage membrane distillation device; 7-3, Third-stage membrane distillation device; 8. Distilled water tank; 9. Electrolytic oxygen and hydrogen production and storage device; 9-1, Electrolytic cell No. 1 of the array-type electrolytic oxygen and hydrogen production device; 9-2, Electrolytic cell No. 2 of the array-type electrolytic oxygen and hydrogen production device; 9-3, Electrolytic cell No. 3 of the array-type electrolytic oxygen and hydrogen production device; 9-n, Electrolytic cell No. n of the array-type electrolytic oxygen and hydrogen production device; 10. Oxygen supply system; 11. Spray water tank; 12. 13. Sprinkler system; 14. Clean water and rainwater collection tank; 15. Automatic monitoring and control module; 16. Submersible pump; 17. Seawater delivery pipe; 18. Valve I; 201. Heating power supply line; 202. Electrolysis power supply line; 203. Oxygen supply power supply line; 204. Photovoltaic module; 205. Corrosion-resistant steel support; 301. Filtered seawater delivery pump; 302. Filtered seawater pipe; 401. Temperature sensor I; 701. Porous hydrophobic membrane; 702. Inlet water circulation pump; 703. Inlet pipe; 704. Distilled water circulation pump; 705. Distilled water inlet pipe; 706. Pressure sensor I; 707. Temperature sensor II; 708. Pressure sensor II; 709. Temperature sensor III; 710. Pressure sensor III; 711. Temperature sensor IV; 712. Pressure sensor IV; 713. Temperature sensor V; 714. Seawater condenser tube; 715. Inlet side; 716. Outlet side; 717. First-stage membrane distillation inlet circulating pump; 718. First-stage membrane distillation inlet side pipe; 719. Second-stage membrane distillation inlet circulating pump; 720. Second-stage membrane distillation inlet side pipe; 721. Third-stage membrane distillation inlet circulating pump; 722. Third-stage membrane distillation inlet side pipe; 901. Distilled water transfer pump; 902. Distilled water pipe; 903. Valve II; 904. Anode electrode plate; 905. Ion exchange membrane; 906. Cathode electrode plate; 907. Anode chamber; 908. Cathode chamber; 909. Oxygen collection pipe; 910. Oxygen scrubber; 911. Oxygen dry... 912. Dryer; 913. Oxygen storage device; 914. Hydrogen collection pipe; 915. Hydrogen scrubber; 916. Hydrogen dryer; 917. Hydrogen storage device; 918. DC power supply; 1001. Oxygen pump; 1002. Oxygen delivery pipe; 1003. Valve III; 1004. Aeration disc; 1005. Electric flow regulating valve; 1006. Oxygen content sensor; 1101. Spray tank inlet pump; 1102. Spray tank inlet pipe; 1103. Valve IV; 1104. Liquid level sensor I; 1201. Spray water delivery pump; 1202. Spray water pipe; 1203. Spray head; 1204. Slider; 1205. Sliding track; 1301. Cleaning water and rainwater delivery pump; 1302. Cleaning water and rainwater pipe;1303. Valve V; 1304. Liquid Level Sensor II; 1305. Clean Water and Rainwater Collection Tank; 1306. Clean Water and Rainwater Collection Pipe; 1307. Automatic On / Off Valve. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1 This invention discloses a comprehensive water resource utilization system based on fishery-solar integration, such as... Figure 1As shown, aquaculture is carried out in the coastal fish farm 1. The photovoltaic power generation system 2 above generates electricity through the photovoltaic effect. The photovoltaic modules are supported by a steel bracket 205 that has undergone anti-corrosion treatment. The two constitute a fishery-solar complementary system. The submersible pump 101 transports seawater from the coastal fish farm 1 to the microfiltration filter 3 for pretreatment to remove large solid particles, suspended particulate matter, microorganisms, and other substances that are prone to scaling. The filtered seawater transfer pump 301 transports the pretreated seawater to the hot water exchange tank 4 through the filtered seawater pipe 302. The solar collector 5 heats the water in the hot water exchange tank 4 to the rated temperature through the photothermal effect. At the same time, the DC power generated by the photovoltaic power generation system 2 powers the electric heater 6 through the heating power supply line 201 for auxiliary heating. The temperature in the hot water exchange tank 4 is monitored in real time by the temperature sensor Ⅰ 401. The inlet water circulation pump 702 circulates water from the heat exchange tank 4 through the inlet pipe 703 in the inlet side 715 of the membrane distillation device 7. The distillation water circulation pump 704 circulates distilled water through the distillation water inlet pipe 705 in the outlet side 716 of the membrane distillation device 7. The circulation reduces temperature polarization and concentration polarization. The inlet side 715 and the outlet side 716 are separated by a porous hydrophobic membrane 701, allowing water vapor in the inlet side 715 to evaporate in gaseous form through the membrane pores to the outlet side 716. The distillation water inlet pipe 705 of the outlet side 716 is fitted with a seawater condenser pipe 714. Pretreated seawater circulates in the seawater condenser pipe 714 to condense the distilled water on the outlet side 716, and the condensed distilled water is collected in the distillation water tank 8. The membrane distillation unit 7 is equipped with temperature sensors and pressure sensors to monitor the operating status in real time. Pressure sensor I 706 and temperature sensor II 707 are installed at the inlet of the water inlet 715, pressure sensor II 708 and temperature sensor III 709 are installed at the outlet of the water inlet 715, pressure sensor III 710 and temperature sensor IV 711 are installed at the inlet of the water outlet 716, and pressure sensor IV 712 and temperature sensor V 713 are installed at the outlet of the water outlet 716. On one hand, the spray tank inlet pump 1101 transports distilled water from the distilled water tank 8 to the spray tank 11 via the spray tank inlet pipe 1102 for use by the spray system 12; on the other hand, by opening valve II 903, the distilled water delivery pump 901 transports distilled water from the distilled water tank 8 to the electrolysis oxygen production and hydrogen production and storage device 9 via the distilled water pipe 902 as the electrolysis water source, and replenishes water during the electrolysis process through the distilled water delivery pump 901 and the distilled water pipe 902. When the ion exchange membrane 905 uses a proton exchange membrane, water is replenished to the anode chamber 907; when the ion exchange membrane 905 uses an anion exchange membrane, water is replenished to the cathode chamber 908.The direct current generated by the photovoltaic power generation system 2 supplies power to the DC power supply 917 through the electrolysis power supply line 202. The positive terminal of the DC power supply 914 is connected to the anode electrode plate 904, and the negative terminal is connected to the cathode electrode plate 906 for electrolysis. During the electrolysis process, the hydrogen generated in the cathode chamber 908 is collected through the hydrogen collection pipe 913 and sent to the hydrogen scrubber 914 for cleaning. After being dried by the hydrogen dryer 915, it is sent to the hydrogen storage device 916 for storage. During the electrolysis process, the oxygen generated in the anode chamber 907 is collected through the oxygen collection pipe 909 and sent to the oxygen scrubber 910 for cleaning. After being dried by the oxygen dryer 911, it is sent to the oxygen storage device 912 for storage, for use by the oxygen supply system 10. The automatic monitoring and control modules involved in this invention all communicate and are automatically controlled by the automatic monitoring and control module 14. The automatic monitoring and control module 14 includes a pressure monitoring and control system, a temperature monitoring and control system, a liquid level monitoring and control system, a flow rate monitoring and control system, a water production monitoring system, an oxygen supply monitoring and control system, a spray monitoring and control system, an electrolysis oxygen production and hydrogen production monitoring and control system, a power generation monitoring and control system, and a power supply control system. The automatic monitoring and control module 14 is used for real-time monitoring and regulation of pressure, temperature, liquid level, flow rate, water production, oxygen supply, spray action, the electrolysis oxygen production and hydrogen production process, and the photovoltaic power generation status.

[0024] like Figure 2 As shown, the photovoltaic power generation system supplies energy to the oxygen supply system 10 through the oxygen supply power line 203. When the oxygen supply system 10 supplies oxygen to the coastal fishing ground 1, it opens valve III 1003. The oxygen pump 1001 delivers oxygen from the oxygen storage device 912 to each aeration plate 1004 through the oxygen delivery pipe 1002 to improve the survival rate of fish. The aeration plates 1004 are arranged in an array in each anti-corrosion steel support 205. An oxygen content sensor 1006 and an electric flow regulating valve 1005 are installed in front of each aeration plate 1004 to monitor and regulate the oxygen content, respectively. The oxygen content sensor 1006 and the electric flow regulating valve 1005 are placed inside the anti-corrosion steel support 205 to prevent corrosion from seawater immersion.

[0025] like Figure 3As shown, when the liquid level sensor I1104 in the spray tank 11 sends a signal that the liquid level has reached the minimum control value, valve IV1103 opens, and the spray tank inlet pump 1101 replenishes water to the spray tank 11 through the spray tank inlet pipe 1102. When the liquid level sensor I1104 sends a signal that the liquid level has reached the maximum control value, valve IV1103 closes, and the spray tank inlet pump 1101 stops replenishing water. When the automatic monitoring and control module 14 detects that the photovoltaic power generation system 2 is partially or entirely unstable or reaches the periodic cleaning period (usually, under the same or similar irradiance and ambient temperature, the output power of the photovoltaic modules is less than 0.85 times the output at the initial state (when the last cleaning ended), the spray system 12 is activated. The spray water delivery pump 1201 delivers water from the spray water tank 11 to each spray head 1203 through the spray water pipe 1202. The spray head 1203 moves back and forth with the slider 1204 that moves back and forth on the sliding track 1205, so that all photovoltaic modules 204 are completely cleaned. The cleaning pressure and angle of the spray head 1203 can be adjusted as needed. Clean water on the surface of photovoltaic module 204 flows by gravity into the clean water and rainwater collection tank 1305. Rainwater dripping onto the surface of photovoltaic module during rainy days is also collected by gravity in the clean water and rainwater collection tank 1305. At the same time, the dripping and flowing of rainwater on the surface of photovoltaic module 204 also has a certain cleaning effect on photovoltaic module 204. The water flowing in the clean water and rainwater collection tank 1305 flows through the clean water and rainwater collection pipe 1307 into the clean water and rainwater collection box 13 for storage (the clean water and rainwater collection tank is set with a certain slope). When the liquid level in the clean water and rainwater collection box 13 reaches the maximum limit value, the liquid level sensor II sends a signal and the automatic opening and closing valve 1306 closes, stopping the water intake.

[0026] Combination Figure 1 and Figure 3As shown, when the water production performance of the membrane distillation unit 7 drops to a certain limit (membrane flux drops to 20%~50%), it indicates that the porous hydrophobic membrane 701 is severely fouled. At this time, the automatic monitoring and control module 14 responds, closing valve I 103 to stop seawater intake, and simultaneously opening valve V 1303. The cleaning water and rainwater delivery pump 1301 sends the water treated by sedimentation in the cleaning water and rainwater collection tank 13 to the microfiltration filter 3 for pretreatment through the cleaning water and rainwater pipe 1302. Because the cleaning water and rainwater in the fishery-solar hybrid system do not contain soil pollution or runoff pollution, only slight air pollution (fishery-solar hybrid systems are generally far from cities, and the content of air pollutants is low) and pollutants on the surface of the photovoltaic modules 204 are washed down during the rainwater's fall. The above pollutants can be mostly removed by the sedimentation effect of the cleaning water and rainwater collection tank 13 and the filtration effect of the microfiltration filter 3. The main pollutant in the membrane distillation seawater desalination process is the deposition of salt on the membrane surface. Rainwater, due to the dissolution of CO2 in the air, is generally slightly acidic (the pH of normal rainfall is about 5.6), which can dissolve the salt on the fouling membrane. Therefore, it has a chemical cleaning function in addition to physical cleaning, effective against both reversible and irreversible fouling. Thus, the clean water pretreated by the microfiltration filter 3 and the water in the rainwater collection tank 13 are sequentially sent to the hot water exchange tank 4 and the inlet water side 715 of the membrane distillation unit to clean the membrane fouling, increase membrane flux, and efficiently produce water. When the membrane flux recovers to a certain value, valve V1303 is closed to stop the intake of clean water and rainwater, while valve I103 is opened, and the seawater desalination module begins normal operation.

[0027] Example 2 like Figure 4 As shown, the seawater desalination module of the multi-stage membrane distillation seawater desalination and array-type electrolysis oxygen-generating and hydrogen-producing system based on fishery-solar complementary technology consists of three hot water exchange tanks and a three-stage membrane distillation unit. The electrolysis oxygen-generating and hydrogen-producing and storage module consists of n array-type electrolysis oxygen-generating and hydrogen-producing electrolytic cells. The operation process is as follows: the power supply method of the electric heater 6 and the DC power supply 917 is the same as... Figure 1The process is consistent with that described above; after pretreatment by the microfiltration filter 3, seawater is sent to the No. 1 hot water exchange tank 4-1. Each solar collector 5 and electric heater 6 heats the water in each hot water exchange tank 4 to the rated temperature. The inlet circulation pump 717 of the first-stage membrane distillation unit 7-1 sends the water from the No. 1 hot water exchange tank 4-1 to the inlet side of the first-stage membrane distillation unit 7-1 through the inlet side pipe 718. The water from the outlet of the inlet side of the first-stage membrane distillation unit 7-1 is sent to the No. 2 hot water exchange tank 4-2. The No. 2 hot water exchange tank 4-2 is used to maintain the inlet side temperature of the second-stage membrane distillation unit 7-2. The inlet circulation pump 719 of the second-stage membrane distillation unit 7-2 sends the water from the inlet side pipe 720 to the second-stage membrane distillation unit 7-2. Water from heat exchange tank 4-2 is fed into the inlet side of the secondary membrane distillation unit 7-2. Water from the outlet of the secondary membrane distillation unit 7-2 is fed into heat exchange tank 4-3. Heat exchange tank 4-3 is used to maintain the inlet temperature of the tertiary membrane distillation unit 7-3. The tertiary membrane distillation unit 7-3 inlet circulation pump 721 sends water from heat exchange tank 4-3 into the inlet side of the tertiary membrane distillation unit 7-3 through the tertiary membrane distillation inlet pipe 722. Water from the outlet of the tertiary membrane distillation unit 7-3 inlet is fed into heat exchange tank 4-1, completing one cycle of the feed liquid on the inlet side of the tertiary membrane distillation unit, and thus circulating continuously. The distilled water condensation process on the outlet side of each membrane distillation unit is similar to... Figure 1 The process is consistent with the above, with distilled water collected in distilled water tank 8; distilled water transfer pump 901 delivers the distilled water from distilled water tank 8 to electrolytic cells No. 1, No. 2, No. 3, and No. n of the array-type electrolytic oxygen-hydrogen production device through distilled water pipe 902 for electrolysis. The hydrogen and oxygen collection and storage methods are the same as those described above. Figure 1 The process is consistent; the application of multi-stage membrane distillation can significantly improve heat utilization efficiency, increase the water production ratio (GOR) of membrane distillation, enhance the clean energy absorption capacity and seawater desalination capacity, while the array-type electrolysis oxygen and hydrogen production device promotes the conversion of clean energy into hydrogen energy to achieve energy storage, enhances the on-site oxygen supply capacity of fish farms, and promotes the modular application of the present invention.

[0028] Example 3 This embodiment discloses a working method for a comprehensive water resource utilization system based on fishery-solar complementary systems according to the above embodiments. The working method is as follows: S1: The seawater of the coastal fishing ground 1 is sent to the microfiltration filter 3 for pretreatment by the submersible pump 101 to remove large solid particles, suspended particulate matter and microorganisms and other substances that are prone to scaling. After pretreatment, it is pumped into the hot water tank 4 for heating. S2: The pretreated seawater is heated to a stable temperature by solar collector 5 (photothermal effect), and electric heater 6 (powered by photovoltaic power generation system) is used for auxiliary heating to improve heating stability. S3: Heated pretreated seawater is fed into the inlet side 715 of the membrane distillation unit 7. Due to the temperature difference between the inlet and outlet sides, the steam pressure difference causes water vapor to evaporate through the membrane pores of the porous hydrophobic membrane 701 to the outlet side 716. The distilled water circulation pipe of the outlet side 716 is covered with a seawater condenser pipe 714 for condensation. Both the inlet and outlet sides are maintained by circulation pumps to reduce temperature polarization and concentration polarization. S4: Distilled water is pumped into the electrolytic cell to produce oxygen and hydrogen through electrolysis. During the electrolysis process, water from the distilled water tank is pumped into the anode chamber 907 (the proton exchange membrane is a diaphragm; if the diaphragm is an anion exchange membrane, water is added to the cathode chamber 908) to continuously replenish the distilled water. The direct current generated by the photovoltaic power generation system 2 powers the electrode plates on both sides through the DC power supply for electrolysis. The hydrogen produced by electrolysis is processed by the hydrogen collection pipe 913 through the hydrogen scrubber 914 and the hydrogen dryer 915 and then sent to the hydrogen storage device 916. The oxygen produced by electrolysis is processed by the oxygen collection pipe 909 through the oxygen scrubber 910 and the oxygen dryer 911 and then sent to the oxygen storage device 912. The oxygen can be supplied to the fish farm to achieve on-site oxygen consumption. S5: The oxygen in the oxygen storage 912 is delivered to the aeration plate 1004 under each photovoltaic support through the oxygen delivery pipe 1002 under the drive of the oxygen pump 1001. The oxygen content sensor monitors the oxygen content online and controls it in real time through the electric flow regulating valve 1005. S6: When the photovoltaic power generation system 2 detects unstable power generation, the spray system starts to work. Usually, when the output power of the photovoltaic modules is lower than 0.85 times the output at the initial state (when the last cleaning ended) under the same or similar irradiance and ambient temperature, the photovoltaic modules are considered for spray cleaning. The water in the spray tank 11 is pumped to each spray head 1203 through the spray pipe to clean each photovoltaic module. During the cleaning process, the slider moves back and forth on the sliding track 1205 to ensure that all photovoltaic modules are cleaned. The clean water generated by the cleaning flows by gravity to the clean water and rainwater collection tank 1305 below and is collected into the clean water and rainwater collection box 13. The clean water and rainwater collection tank 1305 can also collect rainwater on rainy days. S7: When the water production efficiency of the membrane distillation unit 7 drops to a certain level (membrane flux drops to 20%~50%), seawater intake stops. The fresh water collected in the clean water and rainwater collection tank 13 is sent to the hot water exchange tank 4 after pretreatment by sedimentation and microfiltration filter 3. After being heated to a stable temperature, it is sent to the membrane distillation unit 7 to produce water while cleaning the fouled membrane.

[0029] The entire operation of the system of this invention is carried out by the automatic monitoring and control module 14 for data acquisition and optimization control, so as to realize the coordinated operation of seawater desalination, electrolysis oxygen production and hydrogen production, photovoltaic cleaning, membrane self-cleaning and fish farm oxygen supply, thereby maximizing the utilization rate of solar energy and reducing energy consumption.

[0030] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A comprehensive water resource utilization system based on fishery-solar integration, characterized in that, A fishery-solar hybrid module, comprising a coastal fishing ground and a photovoltaic power generation system erected above the fishing ground; The seawater desalination module includes, in sequence, a microfiltration filter, a hot water exchange tank, a membrane distillation device, and a distilled water tank. The inlet of the microfiltration filter is connected to a coastal fishing ground and a clean water and rainwater collection tank, respectively. A solar collector is installed above the hot water exchange tank, and an electric heater is also installed inside. The membrane distillation device includes an inlet side, a porous hydrophobic membrane, and an outlet side. The porous hydrophobic membrane is placed between the inlet side and the outlet side to separate them. An electrolytic oxygen-hydrogen production and storage module, wherein the inlet of the electrolytic oxygen-hydrogen production and storage module is connected to the first outlet of a distilled water tank, and is used to electrolyze distilled water to obtain oxygen and hydrogen and store them separately; The oxygen supply module for the fish farm has its inlet connected to the oxygen storage device of the electrolysis oxygen-generating and hydrogen-producing module and its storage module, and its outlet located in the water body of the fish farm. The spray cleaning and water resource recycling module includes a spray water tank, a spray system, a clean water and rainwater collection trough and a clean water and rainwater collection box. The inlet of the spray water tank is connected to the second outlet of the distilled water tank. The spray system is located above the photovoltaic power generation system. The clean water and rainwater collection trough is located below the photovoltaic module and is connected to the clean water and rainwater collection box. It also includes an automatic monitoring and control module, which collects data on the operating parameters of each module in a unified manner and monitors and regulates them in real time.

2. The comprehensive water resource utilization system based on fishery-solar complementary integration as described in claim 1, characterized in that, The membrane distillation device is a direct contact type, air gap type, scavenging type, or vacuum type membrane distillation configuration; the porous hydrophobic membrane material is PVDF or PTFE, with an average pore size of 0.1 to 5.0 µm; the inlet water temperature is 40 ℃ to 95 ℃, and the outlet water temperature is -2 ℃ to 30 ℃.

3. The comprehensive water resource utilization system based on fishery-solar complementary integration as described in claim 1, characterized in that, The feed liquid of the membrane distillation device and the distilled water in the distillation water tank are both circulated separately; wherein, the distilled water circulation pipe is fitted with a seawater condenser pipe to condense the water vapor that evaporates from the inlet side to the outlet side into distilled water, thereby stabilizing the operating temperature of the outlet side of the membrane distillation device.

4. The comprehensive water resource utilization system based on fishery-solar complementary integration as described in claim 1, characterized in that, Multiple heat exchange tanks can be installed to heat the filtered seawater to different temperatures for use in multi-stage membrane distillation, thereby improving thermal efficiency.

5. The comprehensive water resource utilization system based on fishery-solar complementary integration according to claim 1, characterized in that, The electrolytic oxygen production and hydrogen production and storage module adopts a proton exchange membrane or anion exchange membrane electrolyzer and is arranged in an array-type modular configuration; the DC power supply of the electrolytic oxygen production and hydrogen production and storage module is connected to a photovoltaic power generation system.

6. The comprehensive water resource utilization system based on fishery-solar complementary integration according to claim 1, characterized in that, The fish farm oxygen supply module includes an oxygen pump, an aeration plate, an electric flow regulating valve, and an oxygen content sensor; the oxygen pump delivers oxygen from the oxygen storage device to the aeration plate, with the oxygen content sensor, the electric flow regulating valve, and the aeration plate connected in sequence; the aeration direction of the aeration plate can be automatically adjusted 360°.

7. The comprehensive water resource utilization system based on fishery-solar complementary integration according to claim 1, characterized in that, The spray system includes spray heads, spray pipes, sliders, and sliding tracks; the spray heads are evenly distributed on the spray pipes and are used to connect to distilled water in the spray water tank to clean the photovoltaic modules; the sliders are placed on the sliding tracks on both sides of the spray pipes; the sliding tracks are used to move the spray heads back and forth.

8. The comprehensive water resource utilization system based on fishery-solar complementary integration according to claim 7, characterized in that, The angle between the water flow from the spray head and the plane of the photovoltaic panel is 30° to 90°, and the spray pressure is automatically adjusted according to the pollution level fed back by the automatic monitoring and control module.

9. The comprehensive water resource utilization system based on fishery-solar complementary integration according to claim 1, characterized in that, The system also includes a membrane module self-cleaning module, the inlet of which is connected to the outlet of the clean water and rainwater collection tank.

10. A method for operating a comprehensive water resource utilization system based on fishery-solar complementary systems according to any one of claims 1 to 9, comprising the following steps: S1: Seawater from the coastal fishing grounds is pumped into a microfiltration filter for pretreatment via a submersible pump, and then pumped into a hot water tank for heating. S2: The pretreated seawater is heated to a stable temperature by a solar collector, and an electric heater is used for auxiliary heating to improve heating stability. S3: Heated pretreated seawater is fed into the inlet side of the membrane distillation unit. Water vapor evaporates through the pores of the porous hydrophobic membrane to the outlet side. The distilled water circulation pipe on the outlet side is fitted with a seawater condenser pipe for condensation. Both the inlet and outlet sides are maintained by circulation pumps. S4: Distilled water is pumped into the electrolytic cell to produce oxygen and hydrogen through electrolysis. During the electrolysis process, water from the distilled water tank is pumped into the anode or cathode chamber to continuously replenish the distilled water. The direct current generated by the photovoltaic power generation system powers the electrode plates on both sides through the DC power supply for electrolysis. The hydrogen and oxygen produced by electrolysis are sent into the storage device. S5: The oxygen in the oxygen storage device is delivered to the aeration plate under each photovoltaic support through the oxygen delivery pipe under the drive of the oxygen pump. The oxygen content sensor monitors the oxygen content online and controls it in real time through the electric flow regulating valve. S6: When the photovoltaic power generation system detects that the power generation is unstable, the sprinkler system starts to work; the water in the sprinkler tank is pumped to each sprinkler head through the sprinkler pipe to clean each photovoltaic module. During the cleaning process, the slider moves back and forth on the sliding track. The clean water generated by the cleaning is collected into the clean water and rainwater collection tank after passing through the clean water and rainwater collection tank. S7: When the water production efficiency of the membrane distillation unit drops to a certain level, seawater intake stops. The clean water and fresh water collected in the rainwater collection tank are sent to the hot water exchange tank after sedimentation and microfiltration pretreatment. After being heated to a stable temperature, the water is sent to the membrane distillation unit to produce water while cleaning the fouled membrane.

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