Asymmetric concentrated multi-tube spherical particle interface evaporation seawater desalination system

Abstract

An asymmetric concentrated multi-tube spherical particle interface evaporation seawater desalination system, the interface evaporator adopts the form of spherical heat-absorbing particles floating and stacking. The light-absorbing area is composed of multiple parallel heat-collecting glass tubes and is located at the bottom of the inside of the concentrator. The spherical heat-absorbing particles absorb sunlight, heat the surface water, and produce steam by adjusting the opening of the air valve of the heat-collecting glass tube to match the movement of the light spot. The downward inclined hydrophobic fin on the evaporation section side of the steam condensation waste heat recovery device makes the condensed water quickly fall off, and the condensation section side is used for preheating the new seawater. The system adopts the form of spherical heat-absorbing particles floating and can automatically float with the change of the water level, and is not restricted by the space of the circular heat-collecting glass tube. The multiple parallel heat-collecting glass tubes can reduce the number of concentrators and the consumption of materials. The steam condensation waste heat recovery device physically separates the steam end and the seawater end, has small flow resistance, and high heat exchange efficiency. The system can be applied to the fields of seawater and brackish water desalination, and can solve the problem of drinking water shortage.

Description

Technical Field

[0001] This invention relates to a seawater desalination system, and more particularly to an asymmetric concentrating multi-tube spherical particle interface evaporation seawater desalination system. Background Technology

[0002] Seawater desalination technology is a key approach to solving the global water shortage problem, especially in coastal areas with scarce freshwater resources but abundant marine resources. Currently, the main technologies used include reverse osmosis (RO), multi-stage flash distillation (MSF), and multi-effect distillation (MED), but these typically rely on fossil fuels for energy, increasing operating costs and emitting large amounts of greenhouse gases, exacerbating climate change. Interfacial evaporation seawater desalination technology, a novel solar-driven water treatment method, has received widespread attention in recent years. It utilizes specially designed materials or structures to create interfacial evaporators that effectively absorb energy from sunlight or other heat sources and convert it into heat for evaporating seawater. Simultaneously, it minimizes heat loss to the surrounding environment, thereby improving energy efficiency. Compared to traditional methods, interfacial evaporation technology can operate at lower temperatures, reducing the need for complex equipment and lowering costs.

[0003] Current interfacial evaporation technologies are primarily based on natural, non-concentrated solar energy. This leads to problems such as low energy flux density and surface temperature at the evaporator surface, resulting in low evaporation rates when outdoor temperatures are low. To address this issue, this study proposes an asymmetric, multi-tube, spherical particle interfacial evaporation seawater desalination system. This system collects solar energy around the clock, thereby increasing the evaporation rate. Interfacial evaporation technology directly utilizes renewable solar energy as a driving force, enabling the production of freshwater without increasing carbon emissions. This technology can be applied to water-scarce coastal areas, distributed islands and reefs, and remote brackish water regions inland. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing solar-heated seawater desalination technology and to provide an asymmetric concentrating multi-tube spherical particle interface evaporation seawater desalination system.

[0005] The technical solution of this invention is as follows:

[0006] An asymmetric concentrating multi-tube spherical particle interfacial evaporation seawater desalination system mainly includes a spherical heat-absorbing particle interfacial evaporator, a heat-collecting glass tube, an asymmetric CPC concentrator, a support base, a steam condensation waste heat recovery unit, a freshwater collection tank, a seawater storage tank, a water pump, a fan, a damper, and a temperature sensor. The interfacial evaporator uses spherical heat-absorbing particles that float freely on the water surface inside the heat-collecting glass tube. These particles absorb solar energy collected by the asymmetric CPC concentrator, heating the seawater at the interface and promoting evaporation. Air circulates in the upper part of the heat-collecting glass tube to promptly remove generated water vapor. The water vapor enters the steam condensation waste heat recovery unit, where it exchanges heat with the inclined fins of the heat pipe evaporation section, condenses, and releases heat. The condensate flows through the inclined fins to the freshwater collection area, where it is collected and discharged into the freshwater collection tank through the freshwater outlet. After cooling, the water vapor becomes dry air and, driven by the fan, continues to flow into the heat-collecting glass tube, carrying more water vapor generated by the spherical heat-absorbing particles. Driven by a water pump, the incoming seawater flows through the seawater channel of the steam condenser waste heat recovery unit, exchanges heat with the condenser section of the heat pipe, is preheated, and then enters the collector glass tubes to replenish the evaporated water. Multiple collector glass tubes are arranged in parallel to receive sunlight at different solar altitude angles, which is concentrated by the asymmetric CPC concentrator.

[0007] The spherical heat-absorbing particles are black spheres with a diameter ranging from 0.5 mm to 5 mm. The average density of the heat-absorbing particles is less than that of water. They can be black spheres made of carbonized wood or core-shell forms with an inner layer of wood and an outer layer of titanium nitride particles.

[0008] The aforementioned heat-collecting glass tubes, arranged in multiple layers, are used to receive sunlight concentrated by an asymmetric CPC concentrator. They can be single-layer tubes, double-layer hollow tubes, or vacuum tubes.

[0009] The asymmetric CPC condenser can be made by using a hot-bent tempered glass mirror with silver plating or an aluminum plating, with a glass thickness of 3-4mm; or it can be made by using a thin reflective glass mirror bonded to a PVC backing to form an asymmetric condenser, with the thin reflective mirror thickness of 0.5mm-1.5mm and the PVC backing thickness of 5mm-10mm.

[0010] The glass cover plate can be set at the top of the opening of the asymmetric CPC concentrator, or it can be located on the upper part of the heat collection glass tube to form a rectangular glass cover plate or an arc-shaped glass cover plate, which serves to prevent dust and keep the heat collection glass tube warm.

[0011] The aforementioned steam condensation waste heat recovery unit employs a heat pipe heat exchanger. The inclined fins are treated with a GN-704C hydrophobic coating to enhance condensation efficiency. This coating is located in the evaporation section of the heat pipe, expanding the heat exchange area and facilitating timely removal of condensate. A freshwater collection area is located at the bottom, inclined downwards, to collect condensed freshwater. Seawater flows through the heat pipe condensation section; since water has excellent heat exchange properties, no further heat exchange enhancement is required. The heat pipes can be either circular or flat.

[0012] The opening degree of the air valve can be automatically adjusted according to the outlet temperature of the heat collecting glass tube to adapt to the movement of the light spot in the focusing area and avoid local high temperature of the spherical heat-absorbing particles.

[0013] The system of the present invention has the following advantages:

[0014] This system employs small, spherical heat-absorbing particles that float freely, automatically following changes in water level. It is not constrained by the space of circular heat-collecting glass tubes, overcoming the limitations imposed by the shape and position of plate or disc-shaped interfacial evaporators. The asymmetric concentrators are arranged east-west with a large receiving angle, enabling all-weather solar energy collection and increasing the interfacial evaporation rate. Multiple heat-collecting glass tubes are connected in parallel, effectively reducing the number of concentrators and consumables, thus lowering costs. A heat pipe-type steam condensation waste heat recovery unit utilizes the latent heat of water vapor condensation to preheat seawater. Physical isolation between the steam and seawater ends results in low flow resistance and high heat exchange efficiency. The inclined fins are hydrophobically treated to improve the condensation rate. This system can be deployed in large-scale centralized or small-scale distributed configurations, suitable for water-scarce coastal areas, distributed islands and reefs, and remote brackish water areas inland, addressing drinking water shortages. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of an asymmetric concentrating multi-tube interfacial evaporation seawater desalination system.

[0016] Figure 2 Schematic diagram of an interfacial evaporation device with spherical heat-absorbing particles;

[0017] Figure 3 Schematic diagram of a double-layered heat-collecting glass tube concentrating interface evaporation device;

[0018] Figure 4 Schematic diagram of a rectangular glass cover-plate concentrating interface evaporation device;

[0019] Figure 5 A schematic diagram of a concentrating interface evaporation device with an arc-shaped glass cover.

[0020] Figure 6 A schematic diagram of an asymmetric concentrator;

[0021] Figure 7 This is a top view of an asymmetric concentrating multi-tube interface evaporation device.

[0022] In the diagram: 1. Spherical heat-absorbing particles; 2. Heat-collecting glass tube; 3. Seawater; 4. Air; 5. Asymmetric CPC concentrator; 6. Glass cover; 7. Water vapor; 8. Support base; 9. Steam condenser waste heat recovery unit; 10. Heat pipe working fluid; 11. Heat pipe evaporation section; 12. Heat pipe condensation section; 13. Seawater flow channel; 14. Inclined fins; 15. Baffle; 16. Freshwater collection area; 17. Freshwater outlet; 18. Freshwater collection tank; 19. Freshwater; 20. Seawater storage tank; 21. Water valve; 22. Water pump; 23. Fan; 24. Air valve; 25. Double-layer glass tube; 26. Rectangular glass cover; 27. Arc-shaped glass cover; 28. Glass reflector; 29. ​​PVC back panel; 30. Temperature sensor; 31. Detailed Implementation

[0023] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0024] Examples of embodiments of the present invention Figures 1-7 As shown, Figure 1 The diagram shows an asymmetric concentrating multi-tube interface evaporation seawater desalination system. This system mainly includes spherical heat-absorbing particles 1, heat-collecting glass tubes 2, an asymmetric CPC concentrator 5, a glass cover 6, water vapor 7, a support base 8, a steam condenser waste heat recovery unit 9, heat pipes 10, inclined fins 15, a freshwater collection area 17, a freshwater collection tank 19, a seawater storage tank 21, water valves 22, a water pump 23, a fan 24, an air valve 25, double-layered glass tubes 26, a rectangular glass cover 27, an arc-shaped glass cover 28, a glass reflector 29, and a PVC panel 30. A partition 16 divides the shell of the condenser waste heat recovery unit 9 into a water vapor end and a seawater end. Heat pipes 10 are located inside the shell of the condenser waste heat recovery unit 9. A seawater flow channel 14 is located at the seawater end. The heat pipe evaporation section 12 is located at the water vapor end. The lower seawater inlet of the heat-collecting glass tube 2 connects to the seawater flow channel 14. The upper steam outlet of the heat-collecting glass tube 2 is connected to the steam inlet at the steam end. The dry air outlet at the steam end is sequentially connected to the blower 24, the air valve 25, and the upper dry air inlet of the heat-collecting glass tube 2. The seawater storage tank 21 is sequentially connected to the water valve 22, the water pump 23, and the seawater flow channel 14. The support base 8 is used to support the heat-collecting glass tube 2. A temperature sensor 31 is installed at the upper steam outlet of the heat-collecting glass tube 2.

[0025] The interface evaporator is constructed by stacking and floating spherical heat-absorbing particles. Figure 2These particles float freely on the water surface inside the heat-collecting glass tube, where the water turns into water vapor 7 at the heating interface. The spherical heat-absorbing particles 1 are black spheres with a diameter ranging from 0.5mm to 5mm and an average density less than water. They can be carbonized black wood spheres or core-shell structures with an inner layer of wood and an outer layer of titanium nitride particles. The lower part of the heat-collecting glass tube 2 contains seawater 3, while the upper part carries air 4 to promptly remove the generated water vapor 7. The heat-collecting glass tube 2 can be a single-layer tube, a double-layer hollow tube (e.g., a double-layer glass tube 26), or a vacuum tube. Multiple tubes are arranged side-by-side below the asymmetric CPC concentrator 5 to receive the sunlight concentrated by the asymmetric CPC concentrator 5. The asymmetric CPC concentrator 5 is arranged in an east-west direction and can be made of hot-bent tempered glass with a silver-plated or aluminum-plated mirror, with a glass thickness of 3-4mm; alternatively, multiple glass reflectors 29 can be bonded to a PVC backing plate 30 to form the asymmetric concentrator, with the glass reflectors 29 having a thickness of 0.5mm-1.5mm and the PVC backing plate 30 having a thickness of 5mm-10mm. Figure 6 Glass cover 6 can be positioned at the top of the opening of the asymmetric CPC concentrator. Figure 1 ), or it can be located on the upper part of the heat collecting glass tube 2, forming a rectangular glass cover plate 27 ( Figure 4 ) or curved glass cover plate 28 ( Figure 5 The heat exchanger 10 serves to protect the heat-collecting glass tube 2 from dust and provide insulation. The steam condenser waste heat recovery unit 9 uses a heat pipe heat exchanger, with a partition 16 dividing the hot and cold sections of the heat pipe into an evaporation section 12 and a condensation section 13. The evaporation section 12 exchanges heat on the steam side (i.e., the steam end), while the condensation section 13 exchanges heat on the seawater side (i.e., the seawater end). The surface of the inclined fins 15 is treated with a GN-704C hydrophobic coating to enhance the condensation effect. The inclined fins 15 are arranged in the evaporation section 12 to expand the heat exchange area and promptly remove condensate. The freshwater collection area 17 is located at the bottom of the steam condenser waste heat recovery unit 9, inclined downwards, and is used to collect condensed freshwater. The condensation section 13 is located inside the seawater flow channel 14 for seawater circulation. The heat pipe 10 can be a circular heat pipe or a flat heat pipe. The opening degree of the air valve 25 can be automatically adjusted according to the water vapor outlet temperature of the heat collecting glass tube 2 to adapt to the movement of the light spot in the focusing area and avoid local high temperature of the spherical heat-absorbing particles 1.

[0026] The seawater heating, evaporation, and condensation process is as follows: Sunlight enters the asymmetric CPC concentrator 5, and after passing through the asymmetric reflective surfaces on both sides, the light is focused onto multiple arranged heat-collecting glass tubes 2. Spherical heat-absorbing particles 1 inside the heat-collecting glass tubes 2 absorb the sunlight, heating the seawater at the interface and causing the water to evaporate into water vapor. Air circulates through the upper part of the heat-collecting glass tubes 2, promptly removing the water vapor generated at the interface, reducing water vapor accumulation, and promoting the evaporation process. Then, the generated water vapor 7 enters the steam condensation waste heat recovery unit 9, where it exchanges heat with the inclined fins 15 attached to the heat pipe evaporation section 12. The water vapor 7 condenses and releases heat on the surface of the inclined fins 15, becoming small water droplets, which then slide down to the freshwater collection area 17 and are collected in the freshwater collection tank 19 through the freshwater outlet 18. The condensed water vapor 7 becomes dry air 4, which, driven by the fan 24, re-enters the upper part of the heat-collecting glass tubes 2, continuing to remove the water vapor generated at the interface. This process is repeated continuously. During the concentrated solar evaporation process, the solar altitude angle changes, and the heat absorbed by the spherical heat-absorbing particles 1 inside the heat-collecting glass tube 2 also changes. The opening of the air valve 25 automatically changes with the water vapor outlet temperature of the heat-collecting glass tube 2 (the outlet temperature is measured by the temperature sensor 31) to adapt to the movement of the light spot in the concentrated area, ensuring that the outlet temperatures of multiple heat-collecting glass tubes are similar, while also avoiding local high temperatures in the spherical heat-absorbing particles 1.

[0027] The preheating process of the incoming seawater is as follows: Seawater from the seawater storage tank 21, driven by the water pump 23, flows into the seawater channel 14 of the steam condenser waste heat recovery unit 9, where it undergoes convective heat exchange with the heat pipe condensation section 13. The working fluid 11 of the heat pipe is heated by water vapor 7 in the evaporation section 12, changing from a liquid to a gaseous state. Under pressure, it flows upward to the heat pipe condensation section 13, where it is cooled upon encountering the incoming seawater, condensing from a gaseous state to a liquid state. Then, under the action of gravity and capillary force, it flows back to the evaporation section 12, where it is heated and evaporated again. This cycle repeats, efficiently transferring heat and continuously transferring the heat from the water vapor 7 to the incoming seawater, achieving the purpose of recovering the latent heat of water vapor condensation and preheating the incoming seawater. The water vapor end and the seawater end are physically separated by a partition 16, resulting in low resistance to the flow of both water and water vapor.

Claims

1. An asymmetric concentrating multi-tube spherical particle interface evaporation seawater desalination system, characterized in that, The system includes spherical heat-absorbing particles (1), heat-collecting glass tubes (2), an asymmetric CPC concentrator (5), a steam condensation waste heat recovery unit (9), a freshwater collection tank (19), a seawater storage tank (21), a water pump (23), a fan (24), a damper (25), and a temperature sensor (31). The spherical heat-absorbing particles (1) float freely on the water surface inside the heat-collecting glass tubes (2), absorbing solar radiation and promoting seawater evaporation. Multiple heat-collecting glass tubes (2) are arranged in parallel to receive light rays from different solar altitude angles gathered by the asymmetric CPC concentrator (5). The upper part of the heat-collecting glass tubes (2) is circulated with air to drain the generated water. Steam; water vapor enters the steam condenser waste heat recovery unit (9), exchanges heat with the inclined fins of the heat pipe evaporation section, is condensed and releases heat, and the condensate flows through the inclined fins to the fresh water collection area, is collected together, and is discharged to the fresh water collection tank (19) through the fresh water outlet; after being cooled, the water vapor becomes dry air, and continues to flow into the heat collection glass tube (2) under the drive of the fan (24), and continues to carry the water vapor generated by the spherical heat absorption particles (1); the replenished seawater, driven by the water pump (23), flows through the seawater channel of the steam condenser waste heat recovery unit (9), exchanges heat with the heat pipe condensation section, is preheated, and then enters the heat collection glass tube (2) to replenish the evaporated water; Among them, the opening degree of the air valve (25) can be automatically adjusted according to the water vapor outlet temperature of the heat collecting glass tube (2) to adapt to the movement of the light spot in the focusing area and avoid local high temperature of the spherical heat-absorbing particles (1). The asymmetric concentrating multi-tube spherical particle interface evaporation seawater desalination system adopts a free-floating form of spherical heat-absorbing particles, which can automatically float with changes in water level and are not constrained by the space of circular heat-collecting glass tubes. This overcomes the limitations of plate or disc-shaped interface evaporators due to the shape and position of the container. The asymmetric CPC concentrator is arranged in an east-west direction with a large receiving angle, enabling all-weather solar energy collection and improving the interface evaporation rate. Multiple heat-collecting glass tubes are connected in parallel, which can effectively reduce the number of concentrators and consumables, thereby reducing costs.

2. The system according to claim 1, characterized in that, Spherical heat-absorbing particles (1) are carbonized wood-based black particles; or core-shell structures with an inner wood base and an outer layer of titanium nitride. The particle size of the spherical heat-absorbing particles ranges from 0.5 mm to 5 mm, and the density is less than that of water.

3. The system according to claim 1, characterized in that, The heat collecting glass tubes (2) are composed of multiple tubes arranged in parallel. They are either single-layer tubes, double-layer hollow tubes, or vacuum tubes.

4. The system according to claim 1, characterized in that, The asymmetric CPC condenser (5) is arranged in the east-west direction and is made of hot-bent tempered glass with silver plating or aluminum plating; or a thin reflective glass mirror is attached to a PVC backing to make the condenser, with a thickness of 0.5mm-1.5mm.

5. The system according to claim 1, characterized in that, The glass cover (6) is located on top of the asymmetric CPC concentrator (5) or on the upper part of the heat collection glass tube, forming a rectangular glass cover (27) or an arc-shaped glass cover (28).

6. The system according to claim 1, characterized in that, The steam condensation waste heat recovery unit (9) is a heat pipe heat exchanger. The inclined fins (15) are treated with GN-704C hydrophobic coating and arranged in the heat pipe evaporation section (12) to increase the heat exchange area and remove condensate in time.

7. The desalination system according to claim 1, characterized in that, The freshwater collection area (17) is located at the bottom and is set downwards to collect freshwater.

8. The desalination system according to claim 1, characterized in that, After being cooled, the water vapor becomes dry air and continues to flow into the heat collecting glass tube (2) through the air valve (25) driven by the fan (24). The temperature sensor (31) is set at the water vapor outlet of the heat collecting glass tube (2). The opening of the air valve (25) can be automatically adjusted according to the temperature sensor (31) to regulate the outlet temperature of the heat collecting glass tube (2).

9. The desalination system according to claim 1, characterized in that, The system also includes a support base (8) for supporting the heat collection glass tube (2).

10. The desalination system according to claim 1, characterized in that, The steam condensing waste heat recovery unit (9) adopts a heat pipe heat exchanger. The hot and cold parts of the heat pipe are divided into a heat pipe evaporation section (12) and a heat pipe condensation section (13) by a partition (16). The partition (16) divides the shell of the steam condensing waste heat recovery unit (9) into a steam end and a seawater end. The heat pipe evaporation section (12) exchanges heat at the steam end, and the heat pipe condensation section (13) exchanges heat at the seawater end.

Images