Low-temperature seawater desalination method and device

Abstract

The invention discloses a low-temperature seawater desalination method and device.The seawater desalination method specifically comprises the following steps that S100, raw seawater is introduced into pretreatment equipment and sequentially subjected to grating filtration, ultrafiltration membrane filtration and ion exchange resin adsorption, and pretreated seawater is obtained; s200, feeding the pretreated seawater into seawater heating equipment for heating, and heating the seawater to 50-60 DEG C; s300, the heated seawater is sequentially fed into each stage of flash evaporation chamber of the multi-stage flash evaporation equipment, and in each stage of flash evaporation chamber, the seawater is subjected to flash evaporation due to pressure reduction, and steam is generated; s400, the concentrated seawater subjected to multi-stage flash evaporation is introduced into membrane distillation equipment, a hydrophobic microporous membrane is adopted as a membrane distillation assembly, and water molecules in the concentrated seawater penetrate through membrane holes to form steam under the action of the temperature difference between the two sides of the membrane; and S500, introducing the water vapor generated in the steps S300 and S400 into seawater heating equipment for heat exchange, and heating the seawater while generating condensed fresh water.

Description

Technical Field

[0001] The present invention relates to the technical field of seawater desalination treatment, and in particular to a low-temperature seawater desalination method and device. Background Art

[0002] As global water shortages become increasingly severe, desalination technology has become an important solution to the freshwater crisis. Currently, mainstream desalination technologies include reverse osmosis, multi-stage flash evaporation, and multi-effect distillation, but these technologies have many limitations in practical application. Reverse osmosis relies on high-pressure pumps to provide driving force, which not only consumes a lot of energy but also requires strict seawater pretreatment. Suspended matter, colloids, and microorganisms in the water can easily cause membrane fouling, shortening the life of the membrane components and increasing maintenance costs. Multi-stage flash evaporation and multi-effect distillation are both heat-driven technologies that require large amounts of high-temperature heat sources and typically rely on fossil fuel combustion for energy. This not only results in high operating costs but also produces large amounts of carbon emissions, which is not in line with environmental requirements. Furthermore, when these distillation technologies are operated in low-temperature environments (such as polar research stations and high-latitude coastal areas), insufficient heat source temperature can lead to a significant decrease in evaporation efficiency. Furthermore, the equipment is prone to failure due to low-temperature scaling and icing, seriously affecting system stability.

[0003] The utility model patent with publication number CN104628203B discloses a conditioning device for a low-temperature, multi-effect distillation desalination system. The system includes a water-producing main pipe, a low-temperature, multi-effect distillation desalination device with multiple water-producing pipes connected to the main pipe, a plurality of evaporators connected in series, and flash tanks corresponding to the evaporators. The conditioning device includes a controller, a dosing tank, a dosing pipe, and a pH meter located at the end of the water-producing pipe and connected to the controller signal. The dosing pipe is connected to the outlet pipe side of the evaporator flash tank. The desalination product water conditioning device of this scheme connects the conditioning device to the flash tank. The diluted sodium hydroxide solution enters the product water flash tank by negative pressure suction or by adjusting the amount of the reagent added using a dosing pump, ensuring the stability of the dosing flow and preventing large fluctuations in the pH value.

[0004] The conditioning device provided by the aforementioned patent utilizes a multi-effect distillation method for seawater desalination. However, this desalination method requires the coordination of multiple devices, resulting in high energy consumption. Furthermore, some energy cannot be recovered, resulting in energy waste. For example, when discharging concentrated brine, the large amount of heat contained in the brine cannot be effectively recovered and must be directly discharged, resulting in energy waste. Therefore, designing a desalination method and device with low energy consumption, energy recovery, and adaptability to low-temperature environments has become a pressing technical challenge in the current desalination field. Summary of the Invention

[0005] The purpose of the present invention is to provide a low-temperature seawater desalination method and device, aiming to improve the problems of high energy consumption and non-recyclable energy in existing seawater desalination technology under low-temperature environment.

[0006] The present invention is achieved in that: To achieve the above objectives, according to one aspect of the present invention, a low-temperature seawater desalination method is provided. The specific steps of the seawater desalination method are as follows: S100, introducing raw seawater into a pretreatment device, sequentially filtering through a grid, filtering through an ultrafiltration membrane, and adsorbing through an ion exchange resin to obtain pretreated seawater; S200, sending the pretreated seawater into a seawater heating device for heating, and heating the seawater to 50-60°C; S300, sequentially feeding the heated seawater into each stage of the flash evaporation equipment, wherein the seawater flash evaporates in each stage due to pressure reduction to generate steam; S400, introducing concentrated seawater after multi-stage flash evaporation into a membrane distillation device. The membrane distillation component uses a hydrophobic microporous membrane. Under the action of the temperature difference on both sides of the membrane, water molecules in the concentrated seawater pass through the membrane pores to form steam; S500, introducing the water vapor generated in steps S300 and S400 into a seawater heating device for heat exchange, generating condensed fresh water while heating the seawater; S600, introducing the concentrated seawater with waste heat generated in step S400 into a seawater heating device to exchange heat with seawater; after the heat exchange is completed, the concentrated seawater is discharged to a designated area; S700 , collecting the fresh water generated by condensation in step S500 into a fresh water storage container for storage.

[0007] Preferably, in step S200, the seawater heating equipment includes a primary heating zone, a secondary heating zone, and a tertiary heating zone, and the specific heating steps are as follows: S210, introducing the pretreated seawater into the seawater heating equipment, and the seawater enters the primary heating zone for primary heating; S220, the seawater after the initial heating enters the secondary heating zone, where the secondary heating zone further heats the seawater; S230, a tee joint is provided between the secondary heating zone and the tertiary heating zone, and a temperature sensor is provided on the tee joint for monitoring the temperature of the seawater after being heated in the secondary heating zone; S240. When the seawater temperature meets the standard, it is directly discharged from the seawater heating equipment through the three-way joint and directed to the multi-stage flash evaporation equipment. When the seawater temperature does not meet the standard, the seawater will pass through the three-way joint and enter the three-stage heating zone for further heating to ensure that the seawater temperature meets the standard. The seawater that meets the temperature standard will then be introduced into the multi-stage flash evaporation equipment for flash heating.

[0008] Preferably, in step S300, the pressure of each flash chamber of the multi-stage flash evaporation equipment is gradually reduced, and the steps of flash evaporating the seawater are specifically as follows: S310, the pressure of the first-stage flash chamber is 0.05 MPa. After entering the first-stage flash chamber, the seawater is partially flashed at a pressure of 0.05 MPa. The generated steam enters the manifold and is injected into the seawater heating equipment through the manifold. The remaining seawater enters the second-stage flash chamber; S320, the pressure of the second-stage flash chamber is 0.04MPa. After the seawater enters the second-stage flash chamber, it continues to flash at a pressure of 0.04MPa. The generated steam enters the manifold, and the remaining seawater enters the third-stage flash chamber. S330, the pressure of the third-stage flash chamber is 0.03MPa. After the seawater enters the third-stage flash chamber, it continues to flash at a pressure of 0.03MPa. The generated steam enters the manifold. The remaining seawater is discharged from the third-stage flash chamber and enters the membrane distillation equipment. Steam is generated under the action of the temperature difference on both sides of the membrane. The steam enters the manifold and is injected into the seawater heating equipment.

[0009] According to a second aspect of the present invention, there is provided a low-temperature seawater desalination device, comprising a pretreatment device, a seawater heating device and a multi-stage flash evaporation device, wherein the seawater heating device comprises a primary heating zone, a secondary heating zone and a tertiary heating zone; the pretreatment device is connected to the water inlet of the primary heating zone, the water outlet of the primary heating zone is connected to the water inlet of the secondary heating zone, a tee joint is provided between the water outlet of the secondary heating zone and the water inlet of the tertiary heating zone, for controlling whether the heated seawater flows through the tertiary heating zone; the water outlet of the tertiary heating zone and the water outlet of the tee joint are both connected to the multi-stage flash evaporation device, the water outlet of the multi-stage flash evaporation device is connected to a membrane distillation device, the steam discharge ends of the multi-stage flash evaporation device and the membrane distillation device are connected to the primary heating zone; the water outlet of the membrane distillation device is connected to the secondary heating zone, and the fresh water discharge end in the primary heating zone of the seawater heating device is connected to a fresh water storage container.

[0010] Preferably, the first-level heating zone, the second-level heating zone and the third-level heating zone are all provided with a guide box, a heat exchange coil is provided inside the guide box, two connecting pipes are provided on the guide box, both ends of the heat exchange coil are provided with a first connecting cap, the first connecting caps at both ends of the heat exchange coil are respectively connected to the two connecting pipes, the guide box of the first-level heating zone is provided with a guide pipe, the guide pipe is connected to the connecting pipe on the guide box of the first-level heating zone, for introducing steam and exporting fresh water; the guide box of the second-level heating zone is provided with a control box, and the top of the guide box of the third-level heating zone is provided with a solar panel. Concentrating collector, the water inlet and outlet of the solar concentrating collector are respectively connected to the two connecting pipes on the guide box of the tertiary heating zone, and the water inlet of the solar concentrating collector is connected to a circulating water pump, which is used to drive water to flow inside the solar concentrating collector and the heat exchange coil inside the tertiary heating zone. A phase change material storage box is provided inside the guide box of the tertiary heating zone, and the heat exchange coil inside the guide box of the tertiary heating zone is inserted on the phase change material storage box, which is used for the phase change material to absorb the heat in the heat exchange coil. The circulating water pump, tee joint and guide pipe are all electrically connected to the control box.

[0011] Preferably, the guide box includes a box body and a box cover, and splicing tubes are provided on the top of the front and rear ends of the box body, and the ends of the splicing tubes are provided with a first flange, and the two splicing tubes serve as the water inlet and water outlet of the box body respectively; a connecting head is provided on the connecting pipe, and supporting feet are provided at the corners of the bottom surface of the box body, and an insert ring is provided at the bottom end of the box cover, and the insert ring is inserted into the opening at the top of the box body, and countersunk holes are provided at the corners of the box cover, and the box cover is fixed to the top of the guide box by bolts passing through the countersunk holes, and a sealing gasket is provided between the box cover and the box body; grooves are provided on both sides of the box cover.

[0012] Preferably, the phase change material storage box is provided with multiple installation ports from top to bottom, and each layer of the heat exchange coil from top to bottom is inserted into the inner side of the corresponding installation port; the top of the phase change material storage box is provided with a feed port, and the feed port is provided with a plug, and the phase change material stored inside the phase change material storage box is a capric acid-stearic acid composite PCM.

[0013] Preferably, both ends of the three-way joint are provided with a first electrically controlled valve, the other end is connected to the secondary heating zone, and a temperature sensor is provided on the three-way joint. A support is provided on the top of the three-way joint, and a first distributed I / O module is provided on the top of the support. The ends of the three-way joint are provided with a second flange, the first distributed I / O module is provided with a first communication line, and the end of the first communication line is provided with a first communication plug; The top and bottom of the guide pipe are provided with mounting pipes, and the ends of the mounting pipes are provided with second connecting caps, which are respectively connected to the connecting pipes on the guide box of the primary heating zone; the bottom of the guide pipe is provided with a fresh water outlet, and the top is provided with an air inlet, and the ends of the fresh water outlet and the air inlet are both provided with third connecting caps; an exhaust pipe is provided on the side of the guide pipe, and a second electric control valve is provided above the position where the guide pipe and the exhaust pipe are connected and on the exhaust pipe; a second distributed I / O module is provided on one side of the guide pipe, and the second distributed I / O module is connected to the guide pipe through a connecting plate; a humidity sensor is provided at the bottom of the guide pipe, and the second electric control valve and the humidity sensor are connected The humidity sensors are all connected to the second distributed I / O module, and the humidity sensor is used to judge the humidity of the gas flowing out of the heat exchange coil. When the humidity is too high, the second electrically controlled valve on the guide pipe opens, and the second electrically controlled valve on the exhaust pipe closes, so that the gas re-enters the heat exchange coil through the air inlet for condensation. When the humidity is lower than the specified humidity, the second electrically controlled valve on the guide pipe closes, and the second electrically controlled valve on the exhaust pipe opens, so that the gas can be discharged; the ends of the second distributed I / O modules are each provided with a second communication line, and the ends of the second communication line are provided with a second communication plug, and the second communication plug is used to be connected to the electrical control box.

[0014] Preferably, the solar concentrating collector includes a frame, a drainage tube, a heat collecting plate, tempered glass and a flow tube; the drainage tube is provided with two, and the two drainage tubes are respectively arranged at the top and bottom ends of the inner side of the frame, and a plurality of heat absorption tubes are provided between the two drainage tubes, and the heat absorption tube is provided with a heat absorption plate, the bottom end of the heat absorption plate is inserted into the inner side of the heat absorption tube, and the cross-section of the heat absorption plate is L-shaped, and the drainage tubes are provided with a fixing plate, and the fixing plate is provided with a plurality of fixing holes; the heat collecting plate is arranged in contact with the heat absorption plate, and a supporting platform is provided at the opening of the frame, and the tempered glass is attached to the upper surface of the heat collecting plate and pressed on the supporting platform; the ends of the two drainage tubes are connected to the flow tube, one end of the flow tube is provided with a flow joint, the flow joint is connected to the drainage tube, and the other end of the flow tube is provided with a mounting joint; a support frame is provided at the bottom of the frame, and a plurality of bolt holes are provided at the bottom of the support frame, and the frame is fixed to the top of the guide box in the three-stage heating zone by bolts passing through the bolt holes.

[0015] Preferably, the control box is provided with a plurality of communication slots on the side thereof, and a fixing seat is provided on the back thereof, and a plurality of through holes are provided on both sides of the fixing seat, and the control box is fixed on the secondary heating zone by bolts passing through the through holes; a display screen is provided on the front of the control box, and control buttons are provided on the control box below the display screen; Two external tubes are provided at the end of the circulating water pump, which serve as the water inlet and discharge ends of the water pump respectively, and the ends of the external tubes are provided with adapter caps; one end of the circulating water pump that is attached to the secondary heating zone is provided with a mounting foot, and the mounting foot is provided with multiple mounting holes. A third communication line is provided on the side of the circulating water pump, and a third communication plug is provided at the end of the third communication line, and the third communication plug is electrically connected to the communication slot.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention combines multi-stage flash evaporation with membrane distillation technology to fully utilize the evaporation potential of seawater under low-temperature conditions, thereby increasing freshwater production and desalination efficiency. By utilizing water vapor generated by flash evaporation and membrane distillation, as well as the waste heat from concentrated brine, combined with low-temperature heating, this significantly reduces the high energy consumption of traditional desalination technology, meeting energy conservation and environmental protection requirements.

[0017] 2. The present invention operates in a low temperature environment of 50-60°C, reducing the corrosion of high temperature and high salt to the equipment, extending the service life of the equipment and reducing maintenance costs.

[0018] 3. The present invention adopts a solar concentrating collector as a backup heating energy source, which can ensure that when the seawater is not heated to a specified stable state, the solar concentrating collector is started to continue heating the seawater, thereby ensuring the normal operation of the entire seawater desalination system. At the same time, when the solar concentrating collector is not in use, the heat energy generated by the solar concentrating collector can be stored, effectively saving energy.

[0019] 4. The present invention has a simple structure and can operate independently based on solar energy. It is suitable for scenarios where there is a lack of power supply, such as islands and remote coastal areas, and solves the problem of fresh water shortage in these areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flow chart of the seawater desalination method of the present invention; Figure 2 This is a structural diagram of the connection of various devices for seawater desalination of the present invention; Figure 3 This is a schematic diagram of the structure of the seawater heating device of the present invention with the interior thereof opened; Figure 4 It is a structural schematic diagram of the seawater heating device of the present invention; Figure 5 It is a structural schematic diagram of the guide box of the present invention; Figure 6 Schematic diagram of the structure of the heat exchange coil of the present invention; Figure 7 It is a structural schematic diagram of the phase change material storage box of the present invention; Figure 8It is a structural schematic diagram of the three-way connector of the present invention; Figure 9 It is a structural schematic diagram of the flow guide tube of the present invention; Figure 10 It is a structural schematic diagram of the solar concentrating collector of the present invention; Figure 11 It is a structural schematic diagram of the control box of the present invention; Figure 12 It is a structural schematic diagram of the circulating water pump of the present invention.

[0021] In the figure: 01, primary heating zone; 02, secondary heating zone; 03, tertiary heating zone; 1, guide box; 11, box body; 111, splicing pipe; 112, first flange; 113, connecting pipe; 114, connector; 115, supporting foot; 12, box cover; 121, countersunk hole; 122, groove; 123, insert ring; 2, heat exchange coil; 21, first connecting cap; 3, phase change material storage box; 31, installation port; 32, feed port; 33, seal; 4, three-way connector; 41, temperature sensor; 42, support; 43, first distributed I / O module; 44, first electric control valve; 45, second flange; 46, first communication line; 47, first communication plug; 5, guide pipe; 50, second distributed I / O module; 501, connecting plate; 51, installation pipe; 52, second connecting cap; 53, fresh water Outlet; 54. Third connecting cap; 55. Humidity sensor; 56. Exhaust pipe; 57. Second electric control valve; 58. Air inlet; 59. Second communication line; 591. Second communication plug; 6. Solar concentrating collector; 61. Frame; 611. Base; 612. Support frame; 613. Bolt hole; 62. Drainage pipe; 621. Heat absorption pipe; 622. Fixing plate; 623. Fixing hole; 624. Heat absorption plate; 63. Heat collecting plate; 64. Tempered glass; 65. Flow pipe; 651. Flow joint; 652. Installation joint; 7. Control box; 71. Communication slot; 72. Fixing seat; 73. Through hole; 74. Display screen; 75. Operation button; 8. Circulating water pump; 81. External pipe; 82. Adapter cap; 83. Mounting foot; 84. Mounting hole; 85. Third communication line; 86. Third communication plug. DETAILED DESCRIPTION

[0022] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0023] The following is a further description with reference to the accompanying drawings and specific embodiments: Example

[0024] like Figure 1 and Figure 3 As shown, a low-temperature seawater desalination method, the specific steps of the seawater desalination method are as follows: S100: Raw seawater is introduced into a pretreatment device, where it undergoes grid filtration, ultrafiltration membrane filtration, and ion exchange resin adsorption to produce pretreated seawater. The ion exchange resin is a sodium-type ion exchange resin, which reduces the concentration of calcium and magnesium ions in the pretreated seawater to below 50 mg / L after adsorption. The ultrafiltration membrane has a pore size of 0.1 μm. This prevents the formation of large amounts of scale during subsequent preheating of the raw seawater.

[0025] S200: The pre-treated seawater is sent to the seawater heating equipment for heating to 50-60°C. This temperature can be quickly reached by a low-temperature heat source, and then the seawater can be evaporated by a multi-stage flash evaporation device. The seawater heating equipment includes a first-stage heating zone 01, a second-stage heating zone 02, and a third-stage heating zone 03. The specific heating steps are as follows: S210, introducing the pretreated seawater into the seawater heating equipment, and the seawater enters the primary heating zone 01 for initial heating; S220, the seawater after the initial heating enters the secondary heating zone 02, where the secondary heating zone 02 further heats the seawater; S230, a three-way joint 4 is provided between the secondary heating zone 02 and the tertiary heating zone 03, and a temperature sensor 41 is provided on the three-way joint 4 for monitoring the temperature of the seawater after being heated in the secondary heating zone 02; S240. When the seawater temperature meets the standard, it is directly discharged from the seawater heating device through the three-way joint 4 and directed to the multi-stage flash evaporation device. When the seawater temperature does not meet the standard, the seawater will pass through the three-way joint 4 and enter the three-stage heating zone 03 for further heating to ensure that the seawater temperature meets the standard. The seawater that meets the temperature standard is then introduced into the multi-stage flash evaporation device for flash evaporation.

[0026] S300, the heated seawater is sequentially fed into the flash chambers of each stage of the multi-stage flash evaporation equipment. In each flash chamber, the seawater flashes due to pressure reduction, generating steam. The evaporation chamber is provided with a honeycomb heat exchange plate made of graphene-modified polytetrafluoroethylene with a nano-scale concave-convex structure on the surface. The top of the evaporation chamber is provided with a vacuum pressure gauge and a pressure regulating valve. The pressure of each flash chamber of the multi-stage flash evaporation equipment is gradually reduced. The steps of flash evaporating the seawater are specifically as follows: S310, the pressure of the first-stage flash chamber is 0.05 MPa. After entering the first-stage flash chamber, the seawater is partially flashed at a pressure of 0.05 MPa. The generated steam enters the manifold and is injected into the seawater heating equipment through the manifold. The remaining seawater enters the second-stage flash chamber; S320, the pressure of the second-stage flash chamber is 0.04MPa. After the seawater enters the second-stage flash chamber, it continues to flash at a pressure of 0.04MPa. The generated steam enters the manifold, and the remaining seawater enters the third-stage flash chamber. The pressure in the third-stage flash chamber, S330, is 0.03 MPa. After entering the third-stage flash chamber, seawater continues flashing at 0.03 MPa, generating steam that enters a manifold. The remaining seawater is discharged from the third-stage flash chamber and enters the membrane distillation equipment. The temperature difference across the membrane generates steam, which enters a manifold and is then injected into the seawater heating equipment. The steam generated by each flash chamber is transported through the manifold to the seawater heating equipment, where the fresh water in the steam is condensed using the low-temperature seawater, achieving the purpose of desalination.

[0027] S400: The concentrated seawater after multi-stage flash evaporation is introduced into the membrane distillation equipment. The membrane distillation component uses a hydrophobic microporous membrane. Under the action of the temperature difference on both sides of the membrane, the water molecules in the concentrated seawater pass through the membrane pores to form steam; this can further squeeze out the fresh water in the concentrated seawater, thereby improving the desalination rate of seawater.

[0028] S500, introducing the water vapor generated in steps S300 and S400 into a seawater heating device for heat exchange, generating condensed fresh water and heating the seawater at the same time; this method heats the seawater through the heat generated by steam condensation, and also condenses the water in the steam, thus reducing the use of equipment, saving energy, and effectively utilizing the heat released by the steam condensation.

[0029] S600, introducing the concentrated seawater with waste heat generated in step S400 into a seawater heating device to exchange heat with seawater; after the heat exchange is completed, the concentrated seawater is discharged to a designated area; this method can recover the waste heat in the concentrated seawater and avoid wasting the waste heat in the seawater by directly discharging the concentrated seawater.

[0030] S700 , collecting the fresh water generated by condensation in step S500 into a fresh water storage container for storage, so as to facilitate the storage and subsequent use of the fresh water.

[0031] Example 2 like Figure 2As shown, a low-temperature seawater desalination device includes a pretreatment device, a seawater heating device, and a multi-stage flash evaporation device. The seawater pretreatment device pretreats the seawater to achieve the purpose of decontamination. The seawater heating device includes a primary heating zone 01, a secondary heating zone 02, and a tertiary heating zone 03. The pretreatment device is connected to the water inlet of the primary heating zone 01, and the water outlet of the primary heating zone 01 is connected to the water inlet of the secondary heating zone 02. A three-way joint 4 is provided between the water outlet of the secondary heating zone 02 and the water inlet of the tertiary heating zone 03 to control whether the heated seawater flows through the tertiary heating zone 03. This seawater heating device facilitates heating seawater in different zones, facilitating the timely discharge of heated seawater after the seawater temperature reaches the standard, thereby avoiding energy waste caused by overheating of the seawater. The water outlet of the tertiary heating zone 03 and the water outlet of the three-way joint 4 are both connected to the multi-stage flash evaporation device, which is used to flash evaporate the seawater in stages, causing a large amount of water vapor to evaporate from the seawater for subsequent condensation to produce fresh water. The water outlet of the multi-stage flash evaporation system is connected to a membrane distillation unit, which is used to further evaporate the concentrated seawater and increase its desalination rate. The steam outlets of the multi-stage flash evaporation unit and the membrane distillation unit are connected to the primary heating zone 01, allowing the steam to heat the seawater while simultaneously condensing the steam from the low-temperature seawater, achieving two goals at once. The water outlet of the membrane distillation unit is connected to the secondary heating zone 02, which facilitates the recovery of waste heat from the concentrated seawater discharged from the membrane distillation unit. The freshwater outlet of the primary heating zone 01 of the seawater heating unit is connected to a freshwater storage container for storing freshwater.

[0032] like Figure 3 、 Figure 4 and Figure 6As shown, the first-stage heating zone 01, the second-stage heating zone 02, and the third-stage heating zone 03 are all equipped with a guide box 1. The guide box 1 facilitates the diversion of seawater, thereby facilitating the graded heating of the seawater. The guide box 1 is internally provided with a heat exchange coil 2. The heat exchange coil 2 facilitates the passage of steam, concentrated seawater, or heated water to achieve the purpose of heat exchange with the seawater, thereby facilitating the temperature treatment of the seawater. The guide box is provided with two connecting pipes 113. The connecting pipes 113 facilitate the connection between the guide box and the heat exchange coil 2. This structure also facilitates the assembly and disassembly of the heat exchange coil 2 and facilitates the use of the heat exchange coil 2. The heat exchange coil 2 is provided with a first connecting cap 21 at each end. The first connecting cap 21 at each end of the heat exchange coil 2 is respectively connected to the two connecting pipes 113, making it convenient to assemble and disassemble the heat exchange coil 2 according to the use requirements. The guide box 1 of the primary heating zone 01 is provided with a guide pipe 5, which is connected to the connecting pipe 113 on the guide box 1 of the primary heating zone 01. The guide pipe 5 is used to introduce steam and discharge fresh water, facilitating the separation and diversion of condensed fresh water and gas, and also facilitating the re-introduction of gas into the heat exchange coil 2 when the humidity of the gas is still too high after condensation. The guide box 1 of the secondary heating zone 02 is provided with a control box 7, which facilitates the operation and use of the entire device. The top of the guide box 1 of the tertiary heating zone 03 is provided with a solar concentrating collector 6. The water inlet and outlet of the solar concentrating collector 6 are respectively connected to the two connecting pipes 113 on the guide box 1 of the tertiary heating zone 03. The solar concentrating collector 6 facilitates the collection of heat through solar energy, facilitating the effective heating of seawater when it is needed. The water inlet of the solar concentrating collector 6 is connected to a circulating water pump 8, which is used to drive water flow within the solar concentrating collector 6 and the heat exchange coil 2 within the tertiary heating zone 03. A phase change material storage box 3 is installed within the guide box 1 of the tertiary heating zone 03. The heat exchange coil 2 within the guide box 1 of the tertiary heating zone 03 is inserted into the phase change material storage box 3. The phase change material absorbs heat from the heat exchange coil 2, melting the absorbed phase change material and storing heat. At the same time, the phase change material releases heat when it reacts with seawater, thereby achieving the purpose of heating the seawater. The circulating water pump 8, the three-way connector 4, and the guide pipe 5 are all electrically connected to the control box 7, which facilitates the control box 7 to control the operation of the entire device.

[0033] like Figure 5As shown, the guide box 1 includes a box body 11 and a box cover 12. A splicing pipe 111 is provided at the top of the front and rear ends of the box body 11. The ends of the splicing pipe 111 are provided with a first flange 112. The two splicing pipes 111 serve as the water inlet and outlet of the box body 11 respectively; the splicing pipe 111 is convenient for multiple guide boxes 1 to be stably connected, and it is also convenient for seawater to pass through multiple guide boxes 1 in sequence, thereby achieving the purpose of heating the seawater. A connector 114 is provided on the connecting pipe 113, and the connector 114 is convenient for connecting to other pipes. Support feet 115 are provided at the corners of the bottom surface of the box body 11, and the support feet 115 are convenient for the entire box body 11 to be stably placed on the ground. An insert ring 123 is provided at the bottom end of the box cover 12, and the insert ring 123 is inserted into the top opening of the box body 11 to facilitate the installation and use of the box cover 12. The cover 12 is secured to the top of the induction box 1 with bolts passing through countersunk holes 121, ensuring a stable connection between the cover 12 and the box body 11. A sealing gasket is provided between the cover 12 and the box body 11, ensuring a stable seal between the cover 12 and the box body 11. Slots 122 are provided on both sides of the cover 12 to facilitate assembly and disassembly.

[0034] like Figure 7 As shown, the PCM storage box 3 has multiple installation openings 31 from top to bottom. Each layer of the heat exchange coil 2 is inserted into a corresponding installation opening 31. The installation openings 31 facilitate the installation of the heat exchange coil 2 and facilitate the transfer of heat from the heat exchange coil 2 to the PCM storage box 3. A feed port 32 is provided at the top of the PCM storage box 3, and a plug 33 is installed at the feed port 32 to facilitate the injection of an appropriate amount of PCM into the PCM storage box 3. The PCM stored in the PCM storage box 3 is a capric acid-stearic acid composite PCM.

[0035] like Figure 8 As shown, both ends of the three-way connector 4 are provided with a first electrically controlled valve 44, which is used to conveniently control the opening and closing of the three-way connector 4. The other end is connected to the secondary heating zone 02, so that the hot water heated in the secondary heating zone 02 can enter the three-way connector 4. The three-way connector 4 is also provided with a temperature sensor 41, which is used to conveniently measure the temperature of the seawater passing through the three-way connector 4. The top of the three-way connector 4 is provided with a support 42, and the top of the support 42 is provided with a first distributed I / O module 43. The ends of the three-way connector 4 are provided with a second flange 45. The first distributed I / O module 43 is provided with a first connecting line 46, and the end of the first connecting line 46 is provided with a first connecting plug 47. This method is convenient for connecting to the various electronic control components on the three-way connector 4 through the first distributed I / O module 43, facilitating centralized data collection and controlling the various electronic control components.

[0036] like Figure 9As shown, the guide tube 5 is equipped with mounting tubes 51 at both the top and bottom. The ends of the mounting tubes 51 are equipped with second connecting caps 52, which are respectively connected to the connecting tubes 113 on the guide box 1 of the primary heating zone 01. This structure facilitates the introduction of steam into the heat exchange coil 2 within the primary heating zone 01 through the guide tube 5, while also facilitating the discharge of condensed fresh water through the guide tube 5. The guide tube 5 has a fresh water outlet 53 at its bottom and an air inlet 58 at its top. Both the fresh water outlet 53 and the air inlet 58 are equipped with third connecting caps 54. The fresh water outlet 53 at the bottom allows the condensed fresh water to be discharged, while the air inlet 58 at the top facilitates steam entering the guide tube 5 through the air inlet 58 and then being directed into the heat exchange coil 2. An exhaust pipe 56 is provided on the side of the guide tube 5 to facilitate the discharge of residual gas after condensation. The third connecting cap 54 facilitates connection to the steam transport conduit, facilitating the smooth transport of steam into the primary heating zone 01. A second electrically controlled valve 57 is installed above the junction of the flow conduit 5 and the exhaust pipe 56, as well as on the exhaust pipe 56. This valve controls the connection between the upper and lower sections of the flow conduit 5. A second distributed I / O module 50 is installed on one side of the flow conduit 5. This second distributed I / O module 50 is connected to the flow conduit 5 via a connecting plate 501, stabilizing the module on the flow conduit 5. A humidity sensor 55 is installed at the bottom of the flow conduit 5. Both a second electrically controlled valve 57 and the humidity sensor 55 are connected to the second distributed I / O module 50. The humidity sensor 55 determines the humidity of the gas flowing out of the heat exchange coil 2. When the humidity is too high, the second electrically controlled valve 57 on the flow conduit 5 opens, while the second electrically controlled valve 57 on the exhaust pipe 56 closes, allowing the gas to re-enter the heat exchange coil 2 through the air inlet 58 for condensation. When the humidity falls below a specified humidity, the second electrically controlled valve 57 on the flow conduit 5 closes, while the second electrically controlled valve 57 on the exhaust pipe 56 opens, allowing the gas to be discharged. Under normal circumstances, the gas automatically flows upward, while the fresh water flows out from the bottom of the flow conduit 5 due to gravity, thus achieving the purpose of separating the condensed fresh water and gas. Each end of the second distributed I / O module 50 is equipped with a second interconnection cable 59, and the end of the second interconnection cable 59 is equipped with a second interconnection plug 591. The second interconnection plug 591 is used to connect to the electrical control box 7, facilitating the control of the various components of the flow conduit 5.

[0037] like Figure 10As shown, the solar concentrating collector 6 includes a frame 61, a drainage tube 62, a heat collecting plate 63, tempered glass 64, and a flow tube 65. Two drainage tubes 62 are provided, one at the top and one at the bottom of the inner side of the frame 61. A plurality of heat absorbing tubes 621 are disposed between the two drainage tubes 62. The heat absorbing tubes 621 are provided with a heat absorbing plate 624, the bottom end of which is inserted into the inner side of the heat absorbing tube 621. The heat absorbing plate 624 has an L-shaped cross-section. Each drainage tube 62 is provided with a fixing plate 622, which is provided with a plurality of fixing holes 623. The drainage tubes 62 cooperate with the heat absorbing tubes 621 to facilitate the drainage of the heating medium, facilitate the heating of the heating medium, and facilitate the use of the heating medium. The fixing plate 622 and the fixing holes 623 cooperate to facilitate the fixing of the drainage tubes 62 and the heat absorbing tubes 621 by bolts. The heat collecting plate 63 is positioned against the heat absorbing plate 624 to facilitate the transfer of collected heat to the heat absorbing plate 624. The heat absorbing plate 624 then absorbs the heat and transfers it to the heating medium. A support 611 is provided at the opening of the frame 61. The tempered glass 64 is attached to the upper surface of the heat collecting plate 63 and pressed against the support 611. The ends of the two drainage tubes 62 are each connected to a flow pipe 65. One end of the flow pipe 65 is provided with a flow connector 651, which is connected to the drainage tube 62. The other end of the flow pipe 65 is provided with a mounting connector 652. This structure facilitates the communication between the drainage tube 62 and the heat exchange coil 2 within the tertiary heating zone 03, thereby allowing the heating medium (e.g., water) to flow back and forth within the solar concentrating collector 6 and the heat exchange coil 2. One of the two flow pipes 65 is directly connected to the connecting pipe 113 on the guide box 1 of the tertiary heating zone 03. The other flow pipe 65, without a mounting joint 652 at its bottom end, is connected to the circulating water pump 8. The other end of the circulating water pump 8 is connected via a pipe to the connecting pipe 113 at the bottom of the guide box 1 of the tertiary heating zone 03. A support frame 612 is provided at the bottom of the frame 61. The bottom of the support frame 612 has multiple bolt holes 613. The frame 61 is secured to the top of the guide box 1 of the tertiary heating zone 03 by bolts passing through the bolt holes 613.

[0038] like Figure 11 As shown, the side of the control box 7 is equipped with multiple communication slots 71. These slots facilitate connection between the control box 7 and various components, thereby facilitating control of their operation. A fixing base 72 is located on the back of the control box 7, with multiple through-holes 73 on either side. Bolts passing through these through-holes secure the control box 7 to the secondary heating zone 02, ensuring stable operation. A display screen 74 is located on the front of the control box 7, with control buttons 75 located below the display screen 74. The display screen 74 and control buttons 75 facilitate control of the entire device.

[0039] like Figure 12As shown, the circulating water pump 8 is equipped with two external pipes 81 at its ends, serving as the water inlet and outlet ports of the pump, respectively. Adapter caps 82 are installed at the ends of the external pipes 81. These adapter caps 82 facilitate connection to the flow pipe 65 and other pipes used for fluid diversion. The end of the circulating water pump 8 that abuts the secondary heating zone 02 is equipped with a mounting foot 83. These mounting feet 83 have multiple mounting holes 84, allowing bolts to secure the circulating water pump 8. A third interconnecting cable 85 is installed on the side of the circulating water pump 8. A third interconnecting plug 86 is electrically connected to the interconnecting slot 71, facilitating control of the circulating water pump 8 by the control box. If the seawater temperature is determined to be below standard, the seawater enters the tertiary heating zone 03. Once the seawater enters the tertiary heating zone 03, the control box activates the circulating water pump 8, allowing the heating medium (e.g., water) to flow back and forth between the solar concentrating collector 6 and the heat exchange coil 2.

[0040] Working Principle: Desalination is achieved through the coordinated operation of pretreatment, heating, flash evaporation, membrane distillation, and heat recovery. First, raw seawater is filtered through a pretreatment device's grid, ultrafiltration membrane, and sodium ion exchange resin for adsorption, removing impurities and calcium and magnesium ions to prevent subsequent scaling. The pretreated seawater enters the seawater heating unit, where it flows sequentially through the primary and secondary heating zones 02. A T-joint 4 and temperature sensor 41 between the secondary and tertiary heating zones 03 determine whether to enter the tertiary heating zone 03 based on the water temperature, ensuring the seawater is heated to 50-60°C. The tertiary heating zone 03 utilizes a solar concentrating collector 6 and a phase change material storage box 3 for auxiliary heating and heat storage. Once desalinated, the seawater enters a multi-stage flash evaporation unit. Within each flash chamber, where the pressure decreases, the seawater flashes to produce steam. This steam is then fed through a manifold into the heat exchange coil 2 of the primary heating zone 01 of the seawater heating unit. The concentrated seawater then enters the membrane distillation unit, where the temperature difference across the membrane further generates steam, which is also fed to the primary heating zone 01. In the primary heating zone 01, low-temperature seawater exchanges heat with steam, condensing the steam into fresh water, which is then collected in a freshwater storage container while the seawater is heated. Concentrated seawater, which contains excess heat, exits the membrane distillation unit and enters the secondary heating zone 02, where it exchanges heat with the seawater to be heated, recovering the excess heat. The entire process is coordinated by a control box 7, which, for example, controls the steam condensation cycle based on feedback from a humidity sensor 55, ensuring efficient energy utilization and ultimately completing desalination.

[0041] In summary, compared with the prior art, the present application combines multi-stage flash evaporation with membrane distillation technology to fully utilize the evaporation potential of seawater under low temperature conditions, thereby improving freshwater production and desalination efficiency. The water vapor generated by flash evaporation and membrane distillation and the waste heat of concentrated brine are used as heating energy sources, combined with low-temperature heating methods, which greatly reduces the high energy consumption problem of traditional seawater desalination technology and meets the requirements of energy conservation and environmental protection. Operating in a low-temperature environment of 50-60°C reduces the corrosion of high temperature and high salt to the equipment, extends the service life of the equipment, and reduces maintenance costs. The use of solar concentrating collector 6 as a backup heating energy source can ensure that when the seawater is not heated to a specified stability, the solar concentrating collector 6 is started to continue heating the seawater, ensuring the normal operation of the entire seawater desalination system. At the same time, when the solar concentrating collector 6 is not in use, the heat energy generated by the solar concentrating collector 6 can be stored, effectively saving energy.

[0042] The above is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A low-temperature seawater desalination method, characterized in that: The specific steps of the seawater desalination method are as follows: S100, introducing raw seawater into a pretreatment device, sequentially filtering through a grid, filtering through an ultrafiltration membrane, and adsorbing through an ion exchange resin to obtain pretreated seawater; S200, sending the pretreated seawater into a seawater heating device for heating, and heating the seawater to 50-60°C; S300, sequentially feeding the heated seawater into each stage of the flash evaporation equipment, wherein the seawater flash evaporates in each stage due to pressure reduction to generate steam; S400, introducing concentrated seawater after multi-stage flash evaporation into a membrane distillation device. The membrane distillation component uses a hydrophobic microporous membrane. Under the action of the temperature difference on both sides of the membrane, water molecules in the concentrated seawater pass through the membrane pores to form steam; S500, introducing the water vapor generated in steps S300 and S400 into a seawater heating device for heat exchange, generating condensed fresh water while heating the seawater; S600, introducing the concentrated seawater with waste heat generated in step S400 into a seawater heating device to exchange heat with seawater; after the heat exchange is completed, the concentrated seawater is discharged to a designated area; S700 , collecting the fresh water generated by condensation in step S500 into a fresh water storage container for storage.

2. A low-temperature seawater desalination method according to claim 1, characterized in that: In step S200, the seawater heating equipment includes a primary heating zone (01), a secondary heating zone (02) and a tertiary heating zone (03), and the specific heating steps are as follows: S210, introducing the pretreated seawater into the seawater heating equipment, and the seawater enters the primary heating zone (01) for initial heating; S220, the seawater after the initial heating enters the secondary heating zone (02), and the secondary heating zone (02) further heats the seawater; S230, a three-way joint (4) is provided between the secondary heating zone (02) and the tertiary heating zone (03), and a temperature sensor (41) is provided on the three-way joint (4) for monitoring the temperature of the seawater after being heated in the secondary heating zone (02); S240, when the seawater temperature reaches the standard, it is directly discharged from the seawater heating device through the three-way joint (4), and the seawater is led to the multi-stage flash evaporation device; when the seawater temperature does not reach the standard, the seawater will pass through the three-way joint (4) and enter the three-stage heating zone (03) for further heating to ensure that the seawater temperature reaches the standard, and then the seawater that reaches the standard temperature is introduced into the multi-stage flash evaporation device for flash evaporation heating.

3. A low-temperature seawater desalination method according to claim 2, characterized in that: In step S300, the pressure of each flash chamber of the multi-stage flash evaporation equipment is gradually reduced, and the steps of flash evaporating the seawater are specifically as follows: S310, the pressure of the first-stage flash chamber is 0.05 MPa. After entering the first-stage flash chamber, the seawater is partially flashed at a pressure of 0.05 MPa. The generated steam enters the manifold and is injected into the seawater heating equipment through the manifold. The remaining seawater enters the second-stage flash chamber; S320, the pressure of the second-stage flash chamber is 0.04MPa. After the seawater enters the second-stage flash chamber, it continues to flash at a pressure of 0.04MPa. The generated steam enters the manifold, and the remaining seawater enters the third-stage flash chamber. S330, the pressure of the third-stage flash chamber is 0.03MPa. After the seawater enters the third-stage flash chamber, it continues to flash at a pressure of 0.03MPa. The generated steam enters the manifold. The remaining seawater is discharged from the third-stage flash chamber and enters the membrane distillation equipment. Steam is generated under the action of the temperature difference on both sides of the membrane. The steam enters the manifold and is injected into the seawater heating equipment.

4. A low-temperature seawater desalination device for desalinating seawater in conjunction with the low-temperature seawater desalination method according to claim 3, characterized in that: The invention comprises a pretreatment device, a seawater heating device and a multi-stage flash evaporation device, wherein the seawater heating device comprises a primary heating zone (01), a secondary heating zone (02) and a tertiary heating zone (03); the pretreatment device is connected to the water inlet of the primary heating zone (01), the water outlet of the primary heating zone (01) is connected to the water inlet of the secondary heating zone (02), and a three-way joint (4) is provided between the water outlet of the secondary heating zone (02) and the water inlet of the tertiary heating zone (03) for controlling the heated Whether seawater flows through the tertiary heating zone (03); the water outlet of the tertiary heating zone (03) and the water outlet of the three-way joint (4) are both connected to the multi-stage flash evaporation equipment, the water outlet of the multi-stage flash evaporation equipment is connected to the membrane distillation equipment, and the steam discharge ends of the multi-stage flash evaporation equipment and the membrane distillation equipment are connected to the primary heating zone (01); the water outlet of the membrane distillation equipment is connected to the secondary heating zone (02), and the fresh water discharge end in the primary heating zone (01) of the seawater heating equipment is connected to a fresh water storage container.

5. The low-temperature seawater desalination device according to claim 4, characterized in that: The first-stage heating zone (01), the second-stage heating zone (02) and the third-stage heating zone (03) are all provided with a guide box (1), a heat exchange coil (2) is provided inside the guide box (1), two connecting pipes (113) are provided on the guide box, both ends of the heat exchange coil (2) are provided with a first connecting cap (21), the first connecting caps (21) at both ends of the heat exchange coil (2) are respectively connected to the two connecting pipes (113), the guide box (1) of the first-stage heating zone (01) is provided with a guide pipe (5), the guide pipe (5) is connected to the connecting pipe (113) on the guide box (1) of the first-stage heating zone (01), and is used to introduce steam and discharge fresh water; the guide box (1) of the second-stage heating zone (02) is provided with a control box (7), and the guide box (1) of the third-stage heating zone (03) is provided with a top A solar concentrating collector (6) is provided at the end, and the water inlet and outlet of the solar concentrating collector (6) are respectively connected to two connecting pipes (113) on the guide box (1) of the tertiary heating zone (03), and the water inlet of the solar concentrating collector (6) is connected to a circulating water pump (8) for driving water to flow inside the solar concentrating collector (6) and the heat exchange coil (2) inside the tertiary heating zone (03), and a phase change material storage box (3) is provided inside the guide box (1) of the tertiary heating zone (03), and the heat exchange coil (2) inside the guide box (1) of the tertiary heating zone (03) is inserted into the phase change material storage box (3) for the phase change material to absorb heat in the heat exchange coil (2), and the circulating water pump (8), the three-way joint (4) and the guide pipe (5) are all electrically connected to the control box (7).

6. The low-temperature seawater desalination device according to claim 5, characterized in that: The guide box (1) comprises a box body (11) and a box cover (12). Splicing pipes (111) are provided at the tops of the front and rear ends of the box body (11). The ends of the splicing pipes (111) are each provided with a first flange (112). The two splicing pipes (111) serve as the water inlet and water outlet of the box body (11), respectively. A connecting head (114) is provided on the connecting pipe (113). Support legs (115) are provided at the corners of the bottom surface of the box body (11). An insert ring (123) is provided at the bottom end of the box cover (12). The insert ring (123) is inserted into the top opening of the box body (11). Countersunk holes (121) are provided at the corners of the box cover (12). The box cover (12) is fixed to the top of the guide box (1) by bolts passing through the countersunk holes (121). A sealing gasket is provided between the box cover (12) and the box body (11). Grooves (122) are provided on both sides of the box cover (12).

7. The low-temperature seawater desalination device according to claim 5, characterized in that: The phase change material storage box (3) is provided with a plurality of installation openings (31) from top to bottom, and each layer of the heat exchange coil (2) from top to bottom is respectively inserted into the inner side of the corresponding installation opening (31); a feed opening (32) is provided at the top end of the phase change material storage box (3), and a sealing plug (33) is provided at the feed opening (32); the phase change material stored inside the phase change material storage box (3) is a capric acid-stearic acid composite PCM.

8. The low-temperature seawater desalination device according to claim 5, characterized in that: The three-way connector (4) is provided with a first electric control valve (44) at both ends, and the other end is connected to the secondary heating zone (02), and a temperature sensor (41) is provided on the three-way connector (4), a support (42) is provided on the top of the three-way connector (4), and a first distributed I / O module (43) is provided on the top of the support (42), and a second flange (45) is provided at each end of the three-way connector (4), and the first distributed I / O module (43) is provided with a first communication line (46), and a first communication plug (47) is provided at the end of the first communication line (46); The guide pipe (5) is provided with a mounting pipe (51) at the top and bottom, and a second connecting cap (52) is provided at the end of the mounting pipe (51), and the second connecting cap (52) is respectively connected to the connecting pipe (113) on the guide box (1) of the first heating zone (01); the guide pipe (5) is provided with a fresh water outlet (53) at the bottom, and an air inlet (58) at the top, and the ends of the fresh water outlet (53) and the air inlet (58) are both provided with a third connecting cap (54); an exhaust pipe (56) is provided on the side of the guide pipe (5), and a second electric control valve (57) is provided above the position where the guide pipe (5) and the exhaust pipe (56) are connected and on the exhaust pipe (56); a second distributed I / O module (50) is provided on one side of the guide pipe (5), and the second distributed I / O module (50) is connected to the guide pipe (5) through a connecting plate (501); a humidity sensor (51) is provided at the bottom of the guide pipe (5) 5), the second electric control valve (57) and the humidity sensor (55) are both connected to the second distributed I / O module (50), the humidity sensor (55) is used to judge the humidity of the gas flowing out of the heat exchange coil (2), when the humidity is too high, the second electric control valve (57) on the guide pipe (5) is opened, and the second electric control valve (57) on the exhaust pipe (56) is closed, so that the gas re-enters the heat exchange coil (2) through the air inlet (58) for condensation, when the humidity is lower than the specified humidity, the second electric control valve (57) on the guide pipe (5) is closed, and the second electric control valve (57) on the exhaust pipe (56) is opened, so that the gas can be discharged; the second distributed I / O module (50) is provided with a second communication line (59) at the end, and a second communication plug (591) is provided at the end of the second communication line (59), and the second communication plug (591) is used to be connected to the electric control box.

9. The low-temperature seawater desalination device according to claim 5, characterized in that: The solar concentrating collector (6) comprises a frame (61), a drainage pipe (62), a heat collecting plate (63), tempered glass (64) and a flow pipe (65); two drainage pipes (62) are provided, and the two drainage pipes (62) are respectively provided at the top and bottom ends of the inner side of the frame (61); a plurality of heat absorbing pipes (621) are provided between the two drainage pipes (62); a heat absorbing plate (624) is provided on the heat absorbing pipe (621); the bottom end of the heat absorbing plate (624) is inserted into the inner side of the heat absorbing pipe (621), and the cross section of the heat absorbing plate (624) is L-shaped; a fixing plate (622) is provided on each of the drainage pipes (62); a plurality of fixing holes (623) are provided on the fixing plate (622); the heat collecting plate (63) is fitted with the heat absorbing pipe (621); The plate (624) is provided, and a support platform (611) is provided at the opening of the frame (61), and the tempered glass (64) is attached to the upper surface of the heat collecting plate (63) and pressed on the support platform (611); the ends of the two drainage pipes (62) are connected to the flow pipe (65), one end of the flow pipe (65) is provided with a flow joint (651), the flow joint (651) is connected to the drainage pipe (62), and the other end of the flow pipe (65) is provided with a mounting joint (652); the bottom of the frame (61) is provided with a support frame (612), and the bottom of the support frame (612) is provided with a plurality of bolt holes (613), and the frame (61) is fixed to the top of the guide box (1) of the three-stage heating zone (03) by bolts passing through the bolt holes (613).

10. A low-temperature seawater desalination device according to any one of claims 5 to 9, characterized in that: The control box (7) is provided with a plurality of communication slots (71) on the side, and a fixing seat (72) is provided on the back of the control box (7), and a plurality of through holes (73) are provided on both sides of the fixing seat (72), and the control box (7) is fixed on the secondary heating zone (02) by means of bolts passing through the through holes (73); a display screen (74) is provided on the front of the control box (7), and a control button (75) is provided on the control box (7) below the display screen (74); The end of the circulating water pump (8) is provided with two external pipes (81), the two external pipes (81) serving as the water inlet end and the water outlet end of the water pump respectively, and the end of the external pipe (81) is provided with an adapter cap (82); one end of the circulating water pump (8) abutting the secondary heating zone (02) is provided with a mounting foot (83), the mounting foot (83) is provided with a plurality of mounting holes (84), a third connecting line (85) is provided on the side of the circulating water pump (8), and a third connecting plug (86) is provided at the end of the third connecting line (85), and the third connecting plug (86) is electrically connected to the connecting slot (71).

Images