Janus evaporator and solar seawater desalination collection device

Abstract

The application provides a Janus evaporator and a solar seawater desalination collection device, the Janus evaporator comprises a metal plate, one side of the metal plate is provided with a light absorption layer, and one side is a texture layer, the texture layer is a groove-shaped or net-shaped microstructure obtained by laser processing on the metal plate; the solar seawater desalination collection device comprises a semi-closed condensation collection device, the top and one side of the semi-closed condensation collection device are open, both sides of the Janus evaporator and the condensation plate are connected with the two side walls of the semi-closed condensation collection device, the condensation plate is arranged close to the side of the semi-closed condensation collection device which is not open, and is inclined towards the open side, the Janus evaporator is arranged on the open side of the semi-closed condensation collection device and is inclined towards the non-open side, the texture layer of the Janus evaporator is arranged towards the condensation plate, the bottom of the Janus evaporator extends into seawater through the bottom plate of the semi-closed condensation collection device, and the Janus evaporator, the condensation plate and the side plate and the bottom plate of the semi-closed condensation collection device enclose a vaporization collection chamber, so that water collection is efficiently realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solar light-heat conversion, in particular to a Janus evaporator and a solar seawater desalination collection device. BACKGROUND

[0002] Seawater desalination technology is considered as one of the ideal ways to solve water resource shortage as an important means to optimize water structure. In recent years, the solar-driven interfacial water evaporation technology which is ecological, low-cost, safe and independent of electricity has attracted widespread attention from academia and industry, and has become one of the most promising methods to alleviate the imminent freshwater shortage crisis. In order to solve the above problems, a solar interfacial evaporator based on light-heat evaporation technology has emerged. The solar interfacial water evaporation technology has become a new way to purify water and solve water resource shortage due to its green and pollution-free, high energy utilization sustainability, and provides a feasible solution for small-scale domestic water supply in remote areas, islands and other places.

[0003] The light-heat absorption and water evaporation of the traditional closed solar seawater desalination collection device are in the same closed cover, and a large amount of condensed water droplets are attached to the condensing cover during the evaporation process, which seriously affects the light absorption and makes the evaporation rate drop sharply. Compared with the traditional two-dimensional evaporator, the three-dimensional structure of the solar interfacial evaporator technology greatly improves the evaporation speed by increasing the evaporation area, but the production cost is high and the structure is complex, the long-term stability in complex environment is poor, the overall maintenance amount is large, and it is not suitable for large-scale application. Moreover, due to the disorder and uncontrollability of the holes in the existing main water transportation materials in the solar interfacial evaporator and the high thermal resistance of the materials themselves, the optimization degree is limited. Therefore, how to solve the problems of reducing cost, increasing light-heat conversion efficiency, improving water evaporation efficiency and salt resistance, and realizing industrial application is a difficult problem that puzzles the technical personnel in the field of seawater desalination and wastewater treatment. SUMMARY

[0004] In order to solve the problems in the prior art, the application provides a Janus evaporator and a solar seawater desalination collection device, which has high light-heat conversion efficiency and stable and efficient water evaporation rate, adopts a light-heat absorption and water evaporation separation mode to reduce the light absorption effect of condensed water droplets, and can efficiently realize water collection.

[0005] To achieve the above purpose, the application provides the following technical scheme: a Janus evaporator, comprising a metal plate, one side of the metal plate is provided with a light absorption layer, and the other side is a texture layer, the texture layer is a groove-shaped or net-shaped microstructure obtained by laser processing on the metal plate.

[0006] Further, the light-absorbing layer is obtained by magnetron sputtering a light-thermal coating on a metal plate, and the target material for magnetron sputtering is Al, and the purity of the Al target material is greater than or equal to 99.99%.

[0007] The application further provides a solar seawater desalination collecting device, which comprises a semi-closed condensation collecting device with an open top and one side, and the Janus evaporator and the condensation plate are connected to the two side walls of the semi-closed condensation collecting device, the condensation plate is arranged close to the side of the semi-closed condensation collecting device which is not open and is inclined towards the open side, the Janus evaporator is arranged on the open side of the semi-closed condensation collecting device and is inclined towards the side which is not open, the texture layer of the Janus evaporator is arranged towards the condensation plate, the bottom of the Janus evaporator extends into seawater through the bottom plate of the semi-closed condensation collecting device, and the Janus evaporator, the condensation plate and the side plate and the bottom plate of the semi-closed condensation collecting device form a vaporization collecting chamber.

[0008] Further, the semi-closed condensation collecting device is obtained by bonding laser-engraved transparent acrylic plates.

[0009] Further, the condensation plate comprises a hydrophobic copper mesh layer, a water-absorbing cotton layer and a partition layer, and the hydrophobic copper mesh layer is arranged towards the vaporization collecting chamber.

[0010] Further, a water tank is arranged in the semi-closed condensation collecting device for cooling the condensation plate, the water tank is surrounded by the inner wall of the semi-closed condensation collecting device, the water tank bottom plate and the partition layer of the condensation plate, the water tank bottom plate is fixedly and sealingly connected to the inner wall of the semi-closed condensation collecting device, and there is a gap between the water tank bottom plate and the bottom plate of the semi-closed condensation collecting device.

[0011] Further, the inclination angles of the Janus evaporator and the condensation plate are both 30-60°.

[0012] Further, first and second sliding grooves are formed in the inner walls of the two sides of the semi-closed condensation collecting device, the top of the first sliding groove is close to the top of the second sliding groove, and the bottom of the first sliding groove is far away from the bottom of the second sliding groove, and the Janus evaporator and the condensation plate are fixed in the semi-closed condensation collecting device through the first and second sliding grooves.

[0013] Further, an inclined groove is formed in the bottom plate of the semi-closed condensation collecting device, and the bottom of the Janus evaporator extends into seawater through the inclined groove.

[0014] Further, a water droplet collecting opening is formed in the bottom plate of the semi-closed condensation collecting device, which is used for discharging the condensed water captured by the condensation plate out of the vaporization collecting chamber.

[0015] Compared with the prior art, the application has at least the following beneficial effects:

[0016] The Janus evaporator is provided with a light absorption layer and a texture layer on different surfaces of a metal plate, the outer light absorption layer of the Janus evaporator captures sunlight to obtain energy, the inner texture layer transports water, the texture layer is obtained by laser technology assisted processing of a metal base, the groove-shaped or net-shaped microstructure of the texture layer can be accurately controlled, and the low thermal resistance of the metal base can greatly improve the evaporation efficiency (> 90%), when in use, the outer light absorption layer of the Janus evaporator captures sunlight to obtain energy, and the inner texture layer transports water and realizes water evaporation of the texture layer by using the energy captured by the absorption layer.

[0017] The application provides a solar seawater desalination collection device, a semi-closed condensation collection device is provided, and a Janus evaporator is arranged in the semi-closed condensation collection device, so that the light heat absorption and the water evaporation process are separated, the influence of condensation water droplets on light absorption is avoided, salt accumulation in the texture layer of the Janus evaporator does not cause salt accumulation on the outer light absorption layer, and the harm of salt accumulation to the light absorption layer is prevented from the root; meanwhile, since water vapor is condensed and collected in the vaporization collection chamber, the water vapor generated does not affect the outer light absorption layer of the Janus evaporator, so that the condensation and collection of water vapor in the vaporization collection chamber are not affected by the water vapor, and the long-term and high-efficiency operation of the evaporator is facilitated.

[0018] Further, water evaporation separation and condensation collection are completed in the same vaporization collection chamber, water droplets are collected through the water droplet collection port arranged on the bottom plate, so that fresh water can be quickly collected, and the fresh water does not need to be transported to a designated collection chamber for collection. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 It is a structural schematic view of the solar seawater desalination collection device of the application;

[0020] Fig. 2 It is a structural plan view of the solar seawater desalination collection device of the application;

[0021] Fig. 3 It is a structural perspective view of the solar seawater desalination collection device of the application;

[0022] Fig. 4 It is a texture scanning electron microscope photo of the Janus evaporator;

[0023] Fig. 5 It is a hydrophilicity test diagram of different structures of the Janus evaporator;

[0024] Fig. 6 It is an evaporation rate change diagram of different structures of the Janus evaporator;

[0025] Among them, 1. Janus evaporator, 2. condensation plate, 3. vaporization collection chamber, 4. water trough, 5. bottom plate, 6. first chute, 7. water trough bottom plate, 8. second chute, 9. water drop collection port, 10. chute. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0027] like Figs. 1-3 As shown, the present invention provides a solar desalination collection device, including a Janus evaporator 1, a semi-enclosed condensation collection device made of a transparent material, the semi-enclosed condensation collection device including a condensation plate 2 and a water tank bottom plate 7, the semi-enclosed condensation collection device has an opening on the top and one side, and a first chute 6 and a second chute 8 on the inner walls on both sides, a water tank bottom plate 7 is provided on one side of the semi-enclosed condensation collection device, the water tank bottom plate 7 is fixedly and sealedly connected to the inner wall of the semi-enclosed condensation collection device, the first chute 6 and the second chute 8 are close to each other at the top and far away from each other at the bottom, and the Janus evaporator 1 and the condensation plate 2 are connected by the first chute 6 and the second chute 8. The chute 6 and the second chute 8 are fixed in the semi-enclosed condensation collection device, and the bottom of the Janus evaporator 1 extends into the water from the inclined groove 10 opened on the bottom plate 5 of the semi-enclosed condensation collection device, and the condensation plate 2 is sealed with the water tank bottom plate 7; the Janus evaporator 1, the condensation plate 2 and the bottom plate 5 of the semi-enclosed condensation collection device constitute a vaporization collection chamber 3, the condensation plate 2, the water tank bottom plate 7 and the side wall of the semi-enclosed condensation collection device constitute a water tank 4, and the water in the water tank 4 is used to cool the condensation plate 2. The water vapor generated by the Janus evaporator escapes into the vaporization collection chamber 3 and is captured by the condensation plate 2 and condensed into water droplets.

[0028] Preferably, a water droplet collection port 9 is provided on the bottom plate 5 of the semi-enclosed condensation collection device, and the water vapor generated by the Janus evaporator escapes into the vaporization collection chamber 3, is captured by the condensation plate 2, condenses into water droplets, and flows out of the water droplet collection port 9 for collection.

[0029] Preferably, the Janus evaporator 1 uses a metal plate as a substrate, with a light absorbing layer on one side and a laser-processed texture layer on the other side. The laser-processed texture layer of the Janus evaporator 1 is arranged toward the condenser plate 2. The light absorbing layer is used to convert solar energy into heat energy and conduct it to the laser-processed texture through the metal substrate. The laser-processed texture layer is used to transport water from the bottom to the top through capillary action, and is heated by the converted heat to generate water vapor.

[0030] Preferably, the condensation plate 2 is composed of a hydrophobic copper mesh, absorbent cotton, and a partition from left to right; the hydrophobic copper mesh faces the vaporization collection chamber 3, and the partition faces the water tank 4.

[0031] Preferably, the semi-enclosed condensation collection device is obtained by laser engraving a transparent acrylic plate and bonding it.

[0032] Preferably, the inclination angle of the Janus evaporator 1 and the condensing plate 2 is 30°-60°, and further preferably, 45°. The inclination angle is referred to the solar panel, 60° has the best efficiency but the worst stability, 30° has the worst efficiency and the largest contact area, and the energy waste is also large, therefore, the optimal choice is 45°, so as to maximize the utilization rate.

[0033] The device of the application realizes high-efficiency light-heat conversion by adopting the light-heat absorption and water evaporation separation structure of the Janus evaporator, and the physical barrier of the metal substrate in the Janus evaporator avoids the damage of salt accumulation to the light absorption layer. In addition, the structure adopts the pull-in open structure, which is convenient for replacement of the device.

[0034] Unlike the closed structure seawater desalination treatment device, the structure has the light absorption layer on the outside of the Janus evaporator and the texture layer on the inside, and the condensation water droplets on the indoor texture layer do not affect the outside light absorption layer, avoiding the influence of the condensation water droplets on the light absorption, so as to realize long-term high-efficiency solar evaporation.

[0035] The treatment device structure is simple and convenient to assemble and operate, can promote the evaporation, condensation and collection of water, and realize the rapid and efficient purification and separation of seawater, brackish water, industrial wastewater, domestic wastewater and other water bodies under the action of ordinary sunlight with low energy density.

[0036] Preferably, the mainstream water transportation material in the existing solar interface evaporator has limited optimization degree due to the disorder and uncontrollability of the holes and the high thermal resistance of the material itself. The Janus evaporator of the application can realize micro-precise regulation and control of the holes of the water transportation material by laser technology assisted processing of the metal substrate, and can realize great improvement (>90%) of the evaporation efficiency due to the low thermal resistance of the metal substrate. The preparation method of the Janus evaporator comprises the following steps:

[0037] (1) mainly using cleaned aluminum sheet (ethanol, ultrasonic) as the substrate;

[0038] (2) using magnetron sputtering to coat a light-heat coating on the surface of the aluminum sheet as a light absorption layer;

[0039] (3) then processing the texture capable of realizing water transportation by capillary action on the back surface by laser technology as a laser processing texture layer, that is, obtaining the Janus evaporator.

[0040] Preferably, the aluminum sheet is one of 2A16 and 2A06.

[0041] Preferably, in step (1), the method for pre-treating the surface of the aluminum sheet sample is as follows: the aluminum sheet sample is polished with 150#, 400#, 1000# and 2000# SiC sandpaper in sequence, and then is subjected to polishing treatment, and then is placed in an acetone solution and deionized water for ultrasonic cleaning for 5-10 minutes, and then the aluminum sheet sample is taken out and is blown dry.

[0042] Preferably, in step (2), the method for sputtering the photo-thermal coating is as follows: the aluminum sheet sample pre-treated in step (1) is placed in a rotating disc in a magnetron sputtering vacuum chamber, the distance between the Al target and the aluminum sheet sample is adjusted to 80-120 mm, the vacuum chamber is closed for vacuumization, argon is introduced, the target is subjected to sputtering cleaning, and then the argon flow and the vacuum chamber pressure are adjusted, and a photo-thermal coating is sputtered on the surface of the aluminum sheet sample.

[0043] Further preferably, the purity of the Al target is ≥99.99%, the sputtering cleaning parameters of the target are as follows: the vacuum degree is 0.6 Pa, the sputtering atmosphere flow rate of argon, oxygen and nitrogen is 40-50 sccm, and the sputtering cleaning time is 40 minutes; and the sputtering photo-thermal coating parameters are as follows: the sputtering atmosphere flow rate of argon, nitrogen and oxygen is 40-50 sccm, the vacuum chamber pressure is 0.6 Pa, the sputtering time is 40 minutes, the sputtering power is 200 W, and the sputtering temperature is 100-180°C.

[0044] Preferably, in step (3), the method for laser processing the structure having a capillary effect is as follows: the aluminum sheet sample processed in step (2) is wiped with alcohol on the surface to be processed, and then is cleaned in an ultrasonic cleaner with 40°C distilled water to remove residual contaminants, and then the aluminum sheet with a size of 40×40 mm 2 is subjected to laser processing by using a laser marking machine to make the aluminum sheet have a groove-shaped or net-shaped microstructure.

[0045] Further preferably, the femtosecond laser system parameters are as follows: for the groove-shaped structure, the frequency is 30Khz, the moving speed is 90 mm / s, the energy is 30 W, and the laser spacing is 0.15 mm; and for the net-shaped structure (the angle is 0° and 270°), the frequency is 30Khz, the moving speed is 90 mm / s, the energy is 30 W, and the laser spacing is 0.15 mm.

[0046] As shown in Figs. 4-6 , the test of the Janus evaporator of the present application is as follows:

[0047] 1 Scanning electron microscope test

[0048] The groove-shaped and net-shaped Janus evaporators prepared are cut into small size samples, and the microstructure under a 400μm microscope is obtained by using a scanning electron microscope, and the test results are shown in Fig. 2 , and it can be clearly determined that the microstructure is groove-shaped or net-shaped.

[0049] 2 Hydrophilicity test

[0050] The two types of Janus evaporators were placed on the operating table, and deionized water was dropped on the experimental surface using a dropper. The hydrophilicity of the water droplets on the surface was recorded by a CCD camera. The test results are shown in the figure. Fig. 3 As shown in the figure, the water transport capacity of the trough structure is stronger than that of the net structure.

[0051] 3. Evaporation rate test

[0052] Two different structures of Janus evaporators were used to conduct illumination experiments using simulated sunlight. The test results are shown in the figure below. Fig. 4 As shown in the figure, under one sun irradiation without air convection, the rate of the trough-shaped Janus evaporator reaches 1.48 kg·m -2 ·h -1 The evaporation rate of the Janus evaporator with a mesh structure reaches 1.79 kg·m -2 ·h -1 Through the evaporation rate test, it can be seen that the evaporation rate of the mesh structure Janus evaporator is better than that of the groove structure Janus evaporator. Finally, it is determined that the performance of the mesh structure Jans evaporator is the best.

[0053] The above descriptions are only some embodiments of the present invention and do not limit the present invention. Any modifications made within the basis and conception of the present invention should be included in the scope of protection of the present invention.

Claims

1. A solar desalination collection device, characterized in that: The Janus evaporator (1) comprises a metal plate, a light absorption layer is provided on one side of the metal plate, and a texture layer is provided on the other side, wherein the texture layer is a groove-shaped or mesh-shaped microstructure obtained by laser processing on the metal plate; the light absorption layer is obtained by magnetron sputtering photothermal coating on the metal plate, the target material of the magnetron sputtering is Al, and the purity of the Al target material is ≥99.99%; The invention also includes a semi-enclosed condensation collection device, which is open on the top and one side. Both sides of the Janus evaporator (1) and the condensation plate (2) are connected to the side walls of the semi-enclosed condensation collection device. The condensation plate (2) is arranged near the non-open side of the semi-enclosed condensation collection device and is inclined toward the open side. The Janus evaporator (1) is arranged on the open side of the semi-enclosed condensation collection device and is inclined toward the non-open side. The texture layer of the Janus evaporator (1) is arranged toward the condensation plate (2). The bottom of the Janus evaporator (1) passes through the bottom plate of the semi-enclosed condensation collection device and extends into the seawater. The Janus evaporator (1), the condensation plate (2) and the side plates and bottom plate of the semi-enclosed condensation collection device form a vaporization collection chamber (3).

2. A solar desalination collection device according to claim 1, characterized in that: The semi-enclosed condensation collection device is made by laser engraving transparent acrylic plates and bonding them together.

3. The solar desalination collection device according to claim 1, characterized in that: The condensation plate (2) comprises a hydrophobic copper mesh layer, a water-absorbing cotton layer and a partition layer, and the hydrophobic copper mesh layer is arranged toward the vaporization collection chamber (3).

4. A solar desalination collection device according to claim 3, characterized in that: The semi-enclosed condensation collection device is further provided with a water tank (4) for cooling the condensation plate (2). The water tank (4) is surrounded by a partition layer connected to the inner wall of the semi-enclosed condensation collection device, the water tank bottom plate (7), and the condensation plate (2). The water tank bottom plate (7) is fixedly sealed and connected to the inner wall of the semi-enclosed condensation collection device, and a gap is provided between the water tank bottom plate (7) and the bottom plate of the semi-enclosed condensation collection device.

5. The solar desalination collection device according to claim 1, characterized in that: The inclination angles of the Janus evaporator (1) and the condensation plate (2) are both 30° to 60°.

6. The solar desalination collection device according to claim 1, characterized in that: A first chute (6) and a second chute (8) are provided on inner walls on both sides of the semi-enclosed condensation collection device. The first chute (6) and the second chute (8) are close to each other at the top and far from each other at the bottom. The Janus evaporator (1) and the condensation plate (2) are fixed in the semi-enclosed condensation collection device through the first chute (6) and the second chute (8).

7. The solar desalination collection device according to claim 1, characterized in that: An inclined groove (10) is provided on the bottom plate (5) of the semi-enclosed condensation collection device, and the bottom of the Janus evaporator (1) passes through the inclined groove (10) and extends into the seawater.

8. The solar desalination collection device according to claim 1, characterized in that: A water droplet collection port (9) is provided on the bottom plate (5) of the semi-enclosed condensation collection device for discharging condensed water captured by the condensation plate (2) out of the vaporization collection chamber (3).

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