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

Abstract

The invention discloses an asymmetric condensation multi-tube spherical particle interface evaporation seawater desalination system. An interface evaporator adopts a spherical heat absorption particle floating accumulation form. The multiple heat collection glass tubes are connected in parallel to form a light absorption area and located at the bottom of the inner side of the condenser, the spherical heat absorption particles absorb sunlight and heat water on the surface layer, and steam is generated by adjusting the opening degree of an air valve of the heat collection glass tubes to be matched with movement of light spots. A heat pipe evaporation section side of the steam condensation waste heat recoverer adopts a downwards inclined drainage fin, so that condensed water quickly falls off, and a heat pipe condensation section side is used for preheating new inlet seawater of the system. The system can automatically float along with the change of the water level by adopting a spherical heat-absorbing particle floating form, and is not limited by the space of the circular heat-collecting glass tube; multiple heat collection glass tubes are connected in parallel, so that the number of condensers and consumables can be reduced; the steam condensation waste heat recoverer enables a steam end and a seawater end to be physically isolated, flow resistance is small, and heat exchange efficiency is high. The system can be applied to the fields of seawater, brackish water desalination and the like, and solves the problem of drinking water shortage.

Description

Technical Field

[0001] The invention relates to a seawater desalination system, in particular to an asymmetric light-concentrating multi-tube spherical particle interface evaporation seawater desalination system. Background Art

[0002] Desalination technology is one of the key ways to solve the global water shortage problem, especially in coastal areas with scarce freshwater resources but abundant marine resources. The main technologies currently used include reverse osmosis (RO), multi-stage flash evaporation (MSF), multi-effect distillation (MED), etc., but they usually rely on fossil fuels to provide the required energy, which not only increases operating costs, but also emits a large amount of greenhouse gases, exacerbating climate change. Interfacial evaporation desalination technology is a new solar-driven water treatment method that has received widespread attention in recent years. It uses specially designed materials or structures to prepare interfacial evaporators. These materials can effectively absorb energy from sunlight or other heat sources and convert it into heat for evaporating seawater. At the same time, it minimizes heat loss to the surrounding environment, thereby improving energy utilization efficiency. Compared with traditional methods, interfacial evaporation technology can operate at lower temperatures, reducing the need for complex equipment and reducing costs.

[0003] The interface evaporation technology currently under development is basically a natural non-concentrating form. This means that when the outdoor temperature is low, the energy flux density on the interface evaporator surface is low, the surface temperature is low, and the evaporation rate is low. In order to solve this problem, this study proposes an asymmetric concentrating multi-tube spherical particle interface evaporation seawater desalination system, which collects solar energy all day and night to increase the evaporation rate. Interface evaporation technology can produce fresh water without increasing carbon emissions by directly using renewable solar energy as a driving force. This technology can be applied to coastal water-scarce areas, distributed islands and reefs, and remote inland brackish water areas. Summary of the invention

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

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

[0006] An asymmetric concentrating multi-tube spherical particle interface evaporation seawater desalination system mainly includes a spherical heat-absorbing particle interface evaporator, a heat-collecting glass tube, an asymmetric CPC concentrator, a supporting base, a steam condensation waste heat recovery device, a fresh water collection tank, a seawater storage tank, a water pump, a fan, a wind valve, a temperature sensor, etc. The interface evaporator adopts the form of spherical heat-absorbing particles, which are freely accumulated and float on the water surface in the heat-collecting glass tube, absorb the solar energy collected by the asymmetric CPC concentrator, heat the seawater at the interface, and promote evaporation. Air flows through the upper part of the heat-collecting glass tube to discharge the generated water vapor in time. The water vapor enters the steam condensation waste heat recovery device, exchanges heat with the inclined fins of the heat pipe evaporation section, is condensed and releases heat, and the condensed water flows to the fresh water collection area through the inclined fins, is converged together, and is discharged to the fresh water collection tank through the fresh water outlet. After cooling, the water vapor becomes dry air, and continues to flow into the heat-collecting glass tube driven by the fan, and continues to carry the water vapor generated by the spherical heat-absorbing particles. Driven by a water pump, the newly-incoming seawater flows through the seawater flow channel of the steam condensation waste heat recovery device, exchanges heat with the heat pipe condensation section, is preheated, and then enters the heat collecting glass tube to replenish the evaporated water. Multiple heat collecting glass tubes are arranged in parallel to receive light collected by the asymmetric CPC concentrator at different solar altitude angles.

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

[0008] The heat collecting glass tube is composed of multiple arranged branches and is used to receive the sunlight concentrated by the asymmetric CPC concentrator. It can be a single-layer tube, a double-layer hollow tube or a vacuum tube.

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

[0010] The glass cover plate can be arranged at the top of the opening of the asymmetric CPC concentrator, or can be located on the upper part of the heat collecting glass tube to form a rectangular glass cover plate or an arc glass cover plate, which plays a role in dust prevention and heat preservation of the heat collecting glass tube.

[0011] The steam condensation waste heat recovery device adopts a heat pipe heat exchanger. The inclined fin surface is treated with GN-704C hydrophobic coating to enhance the condensation effect. It is arranged in the evaporation section of the heat pipe to expand the heat exchange area and remove condensed water in time. The fresh water collection area is at the bottom and is tilted downward to collect condensed fresh water. Seawater circulates in the condensation section of the heat pipe. Since water has a good heat exchange effect, no enhanced heat exchange is performed here. The heat pipe can be a round heat pipe or a flat heat pipe.

[0012] The opening 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] The system adopts the free accumulation and floating form of small spherical heat-absorbing particles, which can automatically float with the changes in the water surface level and are not subject to the spatial constraints of the circular collector glass tube. It overcomes the limitation of the plate-shaped or pancake-shaped interface evaporator due to the movement of the container shape and position; the asymmetric concentrator is arranged in the east-west direction with a large receiving angle, which can collect solar energy around the clock and increase the interface evaporation rate; multiple collector glass tubes are connected in parallel, which can effectively reduce the number of concentrators and consumables, thereby reducing costs; a heat pipe steam condensation waste heat recovery device is used to use the latent heat of water vapor condensation to preheat seawater, and the steam end is physically isolated from the seawater end, with low flow resistance and high heat exchange efficiency; the inclined fin surface is hydrophobic to increase the condensation rate. The system can be arranged in a large centralized or small distributed manner, and can be used in coastal water-scarce areas, distributed islands and reefs, and remote inland brackish water areas to solve the problem of drinking water shortage. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of an asymmetric concentrating multi-tube interface evaporation desalination system;

[0016] Figure 2 It is a schematic diagram of the spherical heat-absorbing particle interface evaporation device;

[0017] Figure 3 It is a schematic diagram of the double-layer glass tube concentrating interface evaporation device;

[0018] Figure 4 Schematic diagram of the rectangular glass cover plate focusing interface evaporation device;

[0019] Figure 5 This is a schematic diagram of the arc glass cover plate focusing interface evaporation device;

[0020] Figure 6 Make a schematic for an asymmetric concentrator;

[0021] Figure 7 A top view of an asymmetric focusing multi-tube interface evaporation device.

[0022] In the figure: spherical heat-absorbing particles 1, heat-collecting glass tubes 2, seawater 3, air 4, asymmetric CPC concentrator 5, glass cover 6, water vapor 7, support base 8, steam condensation waste heat recovery device 9, heat pipe 10, heat pipe working medium 11, heat pipe evaporation section 12, heat pipe condensation section 13, seawater flow channel 14, inclined fins 15, partition 16, fresh water collection area 17, fresh water outlet 18, fresh water collection tank 19, fresh water 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 glass cover 28, glass reflector 29, PVC backboard 30, temperature sensor 31. DETAILED DESCRIPTION

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

[0024] Embodiments of the present invention Figure 1-Figure 7 As shown, Figure 1 The figure shows a schematic diagram of an asymmetric concentrating multi-tube interface evaporation seawater desalination system, which mainly includes spherical heat absorbing particles 1, a heat collecting glass tube 2, an asymmetric CPC concentrator 5, a glass cover plate 6, water vapor 7, a supporting base 8, a steam condensation waste heat recovery device 9, a heat pipe 10, an inclined fin 15, a fresh water collection area 17, a fresh water collection tank 19, a seawater storage tank 21, a waterway valve 22, a water pump 23, a fan 24, a wind valve 25, a double-layer glass tube 26, a rectangular glass cover plate 27, an arc glass cover plate 28, a glass reflector 29, and a PVC board 30. Among them, the partition 16 divides the shell of the condensation waste heat recovery device 9 into a water vapor end and a seawater end. The heat pipe 10 is located in the shell of the condensation waste heat recovery device 9. The 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 is connected to the seawater flow channel 14. The upper steam outlet of the heat collecting glass tube 2 is connected to the steam inlet of the water vapor end. The dry air outlet of the water vapor end is sequentially connected to the fan 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 waterway 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 provided at the upper steam outlet of the heat collecting glass tube 2.

[0025] The interface evaporator is composed of spherical heat absorbing particles 1 stacked and floating ( Figure 2), they float freely on the water surface in the heat collecting glass tube, and the water at the heating interface turns into water vapor 7. The spherical heat absorbing particles 1 have a black spherical appearance, with a diameter range of 0.5mm-5mm, and an average density less than water. They can be carbonized wooden black spheres, or they can be a core-shell form with an inner layer of wooden material and an outer layer wrapped with titanium nitride particles. The lower part of the heat collecting glass tube 2 is seawater 3, and the upper part is air 4, which is used to discharge the generated water vapor 7 in time. The heat collecting glass tube 2 can be a single-layer tube, or a double-layer hollow tube (such as a double-layer glass tube 26) or a vacuum tube. Multiple branches of them are arranged in parallel and located at the lower part of the asymmetric CPC concentrator 5 to receive the solar rays concentrated by the asymmetric CPC concentrator 5. The asymmetric CPC concentrator 5 is arranged in the east-west direction and can be made of a heat-bent tempered glass silver-plated mirror or an aluminum-plated mirror, with a glass thickness of 3-4 mm; a glass reflector 29 can also be used, and multiple strips are attached to a PVC backboard 30 to form an asymmetric concentrator, and the glass reflector 29 has a thickness of 0.5 mm-1.5 mm, and the PVC backboard 30 has a thickness of 5 mm-10 mm ( Figure 6 ). The glass cover 6 can be arranged on the top of the opening of the asymmetric CPC concentrator ( Figure 1 ), can also be located on the upper part of the heat collecting glass tube 2, forming a rectangular glass cover plate 27 ( Figure 4 ) or arc glass cover 28 ( Figure 5 ), which plays a role in dust prevention and heat preservation of the heat collecting glass tube 2. The steam condensation waste heat recovery device 9 adopts a heat pipe heat exchanger, and 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 heat pipe evaporation section 12 exchanges heat on the water vapor side (i.e., the water vapor end), and the heat pipe condensation section 13 exchanges heat on the seawater side (i.e., the seawater end). The surface of the inclined fin 15 is treated with a GN-704C hydrophobic coating to enhance the condensation effect. The inclined fin 15 is arranged in the heat pipe evaporation section 12 to expand the heat exchange area and remove condensed water in time. The fresh water collection area 17 is located at the bottom end of the steam condensation waste heat recovery device 9, and is tilted downward to collect condensed fresh water. The heat pipe condensation section 13 is located inside the seawater flow channel 14 for circulating seawater. The heat pipe 10 can be a round heat pipe or a flat heat pipe. The opening degree of the air valve 25 can be automatically adjusted according to the outlet temperature of the water vapor 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 process of seawater heating, evaporation and condensation is as follows: the sunlight enters the asymmetric CPC concentrator 5, and the asymmetric reflective surfaces on both sides irradiate and concentrate the light onto the multiple arranged heat collecting glass tubes 2. The spherical heat absorbing particles 1 in the heat collecting glass tubes 2 absorb the sunlight, heat the seawater at the interface, and evaporate the water into water vapor. The upper part of the heat collecting glass tube 2 is circulated with air to discharge the water vapor generated at the interface in time, reduce the accumulation of water vapor, and promote the evaporation process. Then, the generated water vapor 7 enters the steam condensation waste heat recovery device 9, and 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 to become small water droplets, and then slides down to the fresh water collection area 17, and is collected in the fresh water collection tank 19 through the fresh water outlet 18. The condensed water vapor 7 becomes dry air 4, and enters the upper part of the heat collecting glass tube 2 again under the drive of the fan 24, and continues to take away the water vapor generated at the interface. This process is repeated. During the process of concentrated heat collection and evaporation, the solar altitude angle changes, and the heat absorbed by the spherical heat-absorbing particles 1 in 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), adapting to the movement of the light spot in the concentrated area, ensuring similar outlet temperatures of multiple heat-collecting glass tubes, and also avoiding local high temperatures of the spherical heat-absorbing particles 1.

[0027] The preheating process of the newly-incoming seawater is as follows: the seawater in the seawater storage tank 21, driven by the water pump 23, flows into the seawater flow channel 14 of the steam condensation waste heat recovery device 9, and conducts convection heat exchange with the heat pipe condensation section 13. The heat pipe working fluid 11 is heated by the water vapor 7 in the evaporation section 12, and changes from liquid to gas. Under the action of pressure, it flows upward to the heat pipe condensation section 13, and is cooled when it encounters the newly-incoming seawater, condenses from gas to liquid, and then flows back to the evaporation section 12 under the action of gravity and capillary force, and is heated and evaporated again. The reciprocating cycle and efficient heat transfer continuously transfer the heat of the water vapor 7 to the newly-incoming seawater, realizing the purpose of recovering the latent heat of water vapor condensation and preheating the newly-incoming seawater. The water vapor end and the seawater end are physically separated by the partition 16, and the resistance to the flow of seawater and water vapor is small.

Claims

1. An asymmetric focusing multi-tube spherical particle interface evaporation seawater desalination system, characterized in that: The system comprises spherical heat-absorbing particles (1), a heat-collecting glass tube (2), an asymmetric CPC concentrator (5), a steam condensation waste heat recovery device (9), a fresh water collection tank (19), a seawater storage tank (21), a water pump (23), a fan (24) and a temperature sensor (31); the spherical heat-absorbing particles (1) are freely accumulated and float on the water surface in the heat-collecting glass tube (2), absorbing solar radiation and promoting the evaporation of seawater; a plurality of heat-collecting glass tubes (2) are arranged in parallel to receive light rays collected by the asymmetric CPC concentrator (5) at different solar altitude angles; air flows through the upper part of the heat-collecting glass tube (2) to discharge the generated water vapor; The water vapor enters the steam condensation waste heat recovery device (9), exchanges heat with the inclined fins of the heat pipe evaporation section, is condensed and releases heat, and the condensed water flows to the fresh water collection area through the inclined fins, is converged together, and is discharged to the fresh water collection tank (19) through the fresh water outlet; the water vapor is cooled and becomes dry air, and continues to flow into the heat collecting glass tube (2) driven by the fan (24), and continues to carry the water vapor generated by the spherical heat absorbing particles (1); the supplementary seawater flows through the seawater flow channel of the steam condensation waste heat recovery device (9) driven by the water pump (23), exchanges heat with the heat pipe condensation section, is preheated, and then enters the heat collecting glass tube (2) to supplement the evaporated water.

2. The system according to claim 1, characterized in that The spherical heat-absorbing particles (1) are carbonized black wood particles; or a core-shell structure with an inner layer as a wood base and an outer layer wrapped with 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 a plurality of parallel branches, which are single-layer tubes, double-layer hollow tubes, or vacuum tubes.

4. The system according to claim 1, characterized in that The asymmetric CPC concentrator (5) is arranged in the east-west direction and is made of a heat-bent tempered glass silver-plated mirror or an aluminum-plated mirror; or a thin reflective glass mirror is bonded to a PVC backboard to form a concentrator, and the thickness of the thin reflective glass mirror is 0.5mm-1.5mm.

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

6. The system according to claim 1, characterized in that The steam condensation waste heat recovery device (9) is a heat pipe type heat exchanger. The surface of the inclined fins (15) is treated with a GN-704C hydrophobic coating and arranged in the heat pipe evaporation section (12), which serves to increase the heat exchange area and timely remove condensed water.

7. The desalination system according to claim 1, characterized in that: The fresh water collection area (17) is at the bottom and is arranged to be inclined downwards for collecting fresh water.

8. The desalination system according to claim 1, characterized in that: After being cooled, the water vapor becomes dry air and, driven by the fan (24), continues to flow into the heat collecting glass tube (2) through the air valve (25); a temperature sensor (31) is arranged 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 control the outlet temperature of the heat collecting glass tube (2).

9. The desalination system according to claim 1, characterized in that: The system further comprises a supporting base (8), wherein the supporting base (8) is used to support the heat collecting glass tube (2).

10. The desalination system according to claim 1, characterized in that: The steam condensation waste heat recovery device (9) adopts a heat pipe heat exchanger, and 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 condensation waste heat recovery device (9) into a water vapor end and a seawater end; the heat pipe evaporation section (12) exchanges heat at the water vapor end, and the heat pipe condensation section (13) exchanges heat at the seawater end.

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