Solar energy and wind energy dual-driven self-floating and self-cleaning seawater evaporator

Abstract

The solar energy and wind energy dual-driven self-floating and self-cleaning seawater evaporator comprises a supporting self-floating base and a water absorption evaporation component, a mounting hole is formed in the center of the supporting self-floating base, and the water absorption evaporation component is arranged at the center position of the supporting self-floating base in a penetrating mode. The water absorption evaporation component is tightly matched with the supporting self-floating base; the water absorption evaporation component can absorb sunlight, can realize seawater evaporation by utilizing wind power, and can prevent salt accumulation generated by seawater evaporation; through the structural design, on one hand, the evaporator can absorb solar energy to the maximum extent and convert the solar energy into heat energy for heating seawater; on the other hand, wind can smoothly pass through the surface of the evaporator to take away water vapor and accelerate the evaporation process. The auxiliary effect of wind energy can effectively supplement insufficient solar energy, and it is ensured that the evaporator can still work efficiently under all-weather and different weather conditions.

Description

Technical Field

[0001] The invention relates to the technical fields of interface water evaporation, seawater desalination and sewage treatment, and in particular to a self-floating and self-cleaning seawater evaporator driven by both solar energy and wind energy. Background Art

[0002] As an important means to solve the global water shortage, seawater desalination technology has received widespread attention in recent years. Most of the existing seawater desalination technologies rely on solar energy as the main energy source, using solar radiation to heat the water body, promote water evaporation, and then achieve water separation. However, solar energy is not an all-weather energy source, especially on cloudy days, rainy days or at night, the availability of solar energy is greatly limited. Therefore, in order to ensure that the seawater evaporator can still operate efficiently under all-weather and changeable weather conditions, auxiliary energy must be introduced to supplement the insufficient solar energy.

[0003] As a clean and all-weather energy source, wind energy can effectively use the wind in the natural environment to accelerate the evaporation process. When the wind blows over the surface of the evaporator, it can take away the surface water vapor, thereby reducing the vapor pressure on the surface of the evaporator and promoting further evaporation of water. Based on this, designing a seawater evaporator that can maximize the absorption of sunlight and ensure that wind can pass smoothly through its surface has become an important goal to improve evaporation efficiency and broaden the scope of application.

[0004] In the actual application of seawater desalination, salt precipitation will inevitably occur on the surface of the evaporator. As the evaporation process continues, salt will gradually accumulate on the surface of the evaporator. This is because in the seawater environment, the water contains abundant dissolved salts. As the salt layer gradually thickens, the heat conduction and evaporation performance of the evaporator surface will decrease significantly, and may even lead to a serious decrease in system efficiency. Therefore, solving the problem of salt precipitation accumulation and preventing salt from accumulating on the surface of the evaporator for a long time is the key to ensuring the long-term stable and efficient operation of the evaporator.

[0005] In order to solve this problem, it is particularly important to design an evaporator structure with a self-cleaning function. The self-cleaning function can be achieved through a specific structural design, so that the salt precipitated on the surface of the evaporator can quickly fall back into the water body without forming a thick salt layer on the surface of the evaporator, thereby avoiding the impact of salt scaling on the evaporation performance. In addition, the evaporator should also have self-floating ability, which can enhance the contact between the evaporator and the water body and provide protection for the self-cleaning mechanism. During the floating process of the evaporator, the salt precipitated on the surface can more easily contact and dissolve with the water body under the action of gravity, reducing the risk of salt accumulation.

[0006] Therefore, designing a self-floating, self-cleaning solar-wind dual-energy driven seawater evaporator has become a technical challenge in the field of seawater desalination. This design not only requires the evaporator to have good solar energy absorption capacity, but also to be able to effectively use wind energy to promote the discharge of water vapor; when dealing with the problem of salt precipitation, it is also necessary to ensure that the evaporator surface can be kept clean to continuously maintain efficient evaporation performance.

[0007] In general, how to skillfully integrate solar energy, wind energy, the self-floating ability and self-cleaning function of the evaporator is the key technical difficulty in designing an efficient, stable and adaptable seawater evaporator. Solving these problems will provide a more efficient, economical and sustainable solution for the practical application of seawater desalination technology. Summary of the invention

[0008] In view of the problems existing in the prior art, the present invention proposes a self-floating and self-cleaning seawater evaporator which is driven by both solar energy and wind energy.

[0009] The technical solution of the present invention is as follows: A self-floating and self-cleaning seawater evaporator driven by both solar energy and wind energy comprises a supporting self-floating base and a water absorption and evaporation component. A mounting hole is provided at the center of the supporting self-floating base. The water absorption and evaporation component is passed through the center of the supporting self-floating base and is closely matched with the supporting self-floating base. The water absorption and evaporation component can absorb sunlight and utilize wind power to evaporate seawater at the same time, and can prevent the accumulation of salt produced by the evaporation of seawater.

[0010] Furthermore, the supporting self-floating base is made of foamed PLA material, and has a hollow structure as a whole, with an inverted quadrangular pyramid being dug out from the center to form a mounting hole.

[0011] Furthermore, the density of the water absorption and evaporation component is greater than that of water, so that the water absorption and evaporation component can be tightly combined with the supporting self-floating base.

[0012] Furthermore, the bottom of the water absorption and evaporation component extends out from the floating base and is immersed in the seawater, and the top of the water absorption and evaporation component is exposed from the floating base and is exposed to the air.

[0013] Furthermore, the water absorption and evaporation component adopts an inner and outer petal structure, including an inner petal component and an outer petal component. The inner and outer petal components are respectively V-shaped structures as a whole, and the V-shaped structure is an upper open parabola in the part located below the self-floating base, and is a linear shape in the part located inside the self-floating base and above the self-floating base.

[0014] Furthermore, the upper opening parabola formula of the inner petal component is: ; The upper opening parabola formula of the outer petal component is: ; The straight line of the inner petal component forms an angle of 67.5 to 75° with the horizontal line, and the straight line of the outer petal component forms an angle of 45 to 67.5° with the horizontal line.

[0015] Furthermore, the preparation process of the water absorption and evaporation component is as follows: Step 1) Place appropriate amounts of PVDF powder and GNP powder in an electric hot air drying oven at 65-75°C for 25-30 minutes to remove moisture and ensure complete drying; Step 2) Add 9.5 g of dry PVDF into a beaker containing 50 ml of DMA, place the beaker in a heat-collecting constant temperature heating magnetic stirrer, and stir in a water bath at 70-80°C for 2.5-3.5 hours until the PVDF is completely dissolved to obtain a colorless and transparent PVDF solution; Step 3) Add 0.5 g of dry GNPs to the PVDF solution, continue stirring in a water bath at 70-80°C for 2.5-3.5 hours, and then take it out and perform ultrasonic dispersion for 25-30 minutes to obtain a uniformly dispersed black composite solution; then cover the solution with a breathable membrane and let it stand at room temperature for 7-9 hours to eliminate bubbles for further use; Step 4) After the defoaming process is completed, the black composite solution is injected into the mold using a syringe to completely fill it; after the mold is sealed, it is precooled in a refrigerator at about 3 to 5°C for 5 to 7 hours to prevent cracking during the actual freezing process; after precooling, the mold is placed in a cold trap of a vacuum freeze dryer and frozen at -65 to -70°C for 1.5 to 2.5 hours; Step 5) After complete freezing, the mold is disassembled to obtain a 3D solid composite; Step 6) The solid composite is placed back into the cold trap and freeze-dried at -65 to -70°C and 0.1 Pa for 2.5 to 3.5 hours to sublime the DMA solvent and form a 3D water absorption and evaporation component.

[0016] The beneficial effects of the present invention are as follows: 1) Solar and wind dual drive structure: The evaporator is designed to absorb solar energy to the maximum extent and convert it into heat energy for heating seawater. On the other hand, it allows wind to pass smoothly through the surface of the evaporator, taking away water vapor and accelerating the evaporation process. The auxiliary role of wind energy can effectively supplement the lack of solar energy and ensure that the evaporator can still work efficiently under all-weather and different climate conditions.

[0017] 2) Self-floating structure: The evaporator can float on the water surface through lightweight materials and reasonable buoyancy design; this self-floating structure provides a guarantee for the evaporator's self-cleaning function and adaptive wind direction function.

[0018] 3) Self-cleaning structure: In a seawater environment, salt precipitation will inevitably occur on the surface of the evaporator. As the working time increases, salt will gradually accumulate and affect the evaporation efficiency. The present invention uses a special structural design to enable the evaporator surface to have a self-cleaning function. When salt is precipitated and deposited on the surface of the evaporator, due to the self-floating structure and gravity, the precipitated salt can automatically fall into the water below, avoiding excessive accumulation of salt, keeping the evaporator surface clean, and ensuring stable evaporation efficiency.

[0019] 4) The water absorption evaporator component adopts a double-layer structure of inner and outer petals, in which the inner petals are long and the outer petals are short. The existence of the outer petals increases the evaporation area of ​​the interface water, which is more conducive to improving the evaporation rate of the evaporator; the water absorption evaporation component has an inner and outer petal structure, and the part below the self-floating base is an upper open parabola, ensuring that the area of ​​the evaporator under water is as large as possible, so that it can absorb water more fully; the part inside and above the self-floating base is a straight line, ensuring that it is more stable with the supporting self-floating base. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall three-dimensional structure of the present invention; Figure 2 It is a front structural schematic diagram of the present invention; Figure 3 It is a side structural schematic diagram of the present invention; Figure 4 Schematic diagram of the structure of the self-floating support base of the present invention; Figure a is a three-dimensional structure diagram; Figure b is a cross-sectional diagram in the length direction; Figure c is a cross-sectional diagram in the width direction; Figure 5 This is a physical picture of the water absorption and evaporation component of the present invention; Figure 6 A flow chart for preparing the water absorption and evaporation component of the present invention; Figure 7 This is a schematic diagram of the principle of absorbing sunlight of the present invention; Figure 8 A schematic diagram of preventing salt accumulation according to the present invention; Fig. 9 This is a schematic diagram of the wind energy utilization principle of the present invention; Fig.10 It is a schematic diagram of the self-rotation of the present invention; In the figure: 1, supporting self-floating base; 101, mounting hole; 2, water absorption and evaporation component; 201, inner petal component; 202, outer petal component. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings.

[0022] The technical problem to be solved by the present invention is how to maximize the absorption of sunlight and effectively utilize wind power while preventing the accumulation of salt caused by long-term evaporation in seawater.

[0023] The present invention as a whole is composed of two parts, one part is the water absorption and evaporation component 2, and the other part is the supporting self-floating base 1.

[0024] The overall preparation process is completed in three steps.

[0025] Step 1: Preparation process of water absorption and evaporation components: like Figure 6 As shown, first, an appropriate amount of PVDF powder (polyvinylidene fluoride (powder, high viscosity, high mechanical properties, extrusion molding.) purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) and GNP (nanographite powder, D50 <400nm, metal base ≥99.95%, purchased from Shanghai McLean Biochemical Technology Co., Ltd.) was placed in an electric blast drying oven at 70°C for 30 minutes to remove moisture and ensure complete drying. Subsequently, 9.5 grams of dried PVDF was added to a beaker containing 50 milliliters of DMA (analytical grade, content (GC) ≥99.0%, purchased from Sinopharm Chemical Reagent Co., Ltd.), and the beaker was placed in a heat-collecting constant temperature heating magnetic stirrer, and stirred in a 75°C water bath for 3 hours until the PVDF was completely dissolved to obtain a colorless and transparent PVDF solution. Next, 0.5 grams of dried GNPs were added to the PVDF solution, and the stirring continued in a 75°C water bath for 3 hours. After the end, it was taken out and ultrasonically dispersed for 30 minutes to obtain a uniformly dispersed black composite solution. The solution was then covered with a breathable film and allowed to stand at room temperature for 8 hours to remove bubbles for further use. After the defoaming process is completed, the black composite solution was injected into the mold using a syringe to fill it completely. After the mold was sealed, it was precooled in a refrigerator at about 4°C for 6 hours to prevent cracking during the actual freezing process. After precooling, the mold was placed in the cold trap of a vacuum freeze dryer (model ZLGJ-10 purchased from Zhengzhou Fujing Technology Co., Ltd.) and frozen at -70°C for 2 hours. Once completely frozen, the 3D solid composite was obtained by carefully disassembling the mold. Finally, the solid composite was placed back in the cold trap and freeze-dried at -70°C and 0.1 Pa for 3 hours to sublimate the DMA solvent to form a 3D water-absorbing and evaporating component, as shown in the structural diagram. Figure 1 As shown in the figure, the effect is as follows Figure 5 shown.

[0026] The water absorption and evaporation component 2 adopts an inner and outer petal structure, including an inner petal component 201 and an outer petal component 202. The inner and outer petal components 201 and 202 are respectively V-shaped structures as a whole, and the V-shaped structure is an upper open parabola at the part below the self-floating base, and is a linear shape at the part inside the self-floating base and above the self-floating base.

[0027] Specifically, the upper opening parabola formula of the inner petal component 201 is: The straight line of the inner petal component 201 is at an angle of 67.5° to the horizontal line, and the upper opening parabola formula of the outer petal component 202 is: ; The straight line of the outer petal part 202 forms an angle of 45° with the horizontal line.

[0028] Step 2: Preparation of the self-floating base First, the Solidworks software was used to model and design a supporting self-floating base. The specific parameters are as follows: a cube with a length × width × height of 5 cm × 5 cm × 0.5 cm, and an inverted quadrangular pyramid with an upper top surface side length of 1.5 cm and a lower bottom surface side length of 17.07 cm was dug out from the center (the acute angle of the side section trapezoid is 45°, and the angle between the straight line and the horizontal line of the evaporator outer petal component is the same), forming a mounting hole 101. The entire base is a hollow structure. Then, the foamed PLA low-density material (purchased from Shenzhen Tuozhu Technology Co., Ltd.) was used to start printing (Tuozhu X1C 3D printer). After completion, it can be removed and used after cooling. Figure 4 shown.

[0029] Step 3: Preparation of self-floating and self-cleaning seawater evaporator By planning the size of the evaporator and the base, the water absorption and evaporation component of the first step is perfectly combined with the supporting self-floating base of the second step, avoiding the impact of the additional use of glue and other adhesives. At the same time, because the water absorption and evaporation component is denser than water, it will generate a downward force, and the supporting self-floating base will be subject to an upward buoyancy. Finally, the two forces interact with each other, so that the water absorption and evaporation component is tightly combined with the supporting self-floating base. Finally, the vertical distance between the top of the water absorption and evaporation component and the supporting self-floating base is 3cm, and the vertical distance between the bottom of the water absorption and evaporation component and the supporting self-floating base is 1.3cm. Figure 2 , 3 shown.

[0030] Working principle: like Figure 7 As shown, the structural design of the water absorption and evaporation component can enhance the absorption of light by multiple reflections of sunlight, and can also enable natural wind to pass through the surface of the membrane without obstacles.

[0031] like Figure 8 As shown, the salt produced by the long-term evaporation of seawater is deposited on the surface of the evaporator. Since the evaporator is partially below the water surface, the precipitated salt can automatically fall into the water below under the action of gravity, avoiding the efficiency decline of the traditional evaporator caused by salt scaling, keeping the evaporator surface clean, and ensuring stable evaporation efficiency.

[0032] like Fig. 9 As shown in the figure, when the front of the evaporator is consistent with the wind direction (the direction indicated by the arrow in the figure), the wind can pass through the evaporator surface unimpeded and take away the steam generated by the evaporation of the evaporator, reducing the saturated steam pressure on the evaporator surface, thereby increasing the evaporation rate and evaporation efficiency. When the wind blows to the side of the evaporator, such as Fig.10 As shown in the figure, since the evaporator is floating on the water, the evaporator will rotate automatically to adapt to the direction of the wind, so as to ensure that the wind can pass through the evaporator without obstacles at all times.

[0033] Finally, the present invention gives the evaporation rate (kg m -2 h -1 ) are compared, as shown in the following table: ; In the above table: 1 sun means: standard sunlight intensity, i.e. 1000Wm -2 ; 1 sun - 0 wind speed means: standard sunlight intensity and wind speed is 0ms -1 ; 1 sun - 2 wind speed means: standard sunlight intensity and wind speed is 2ms -1 ; 1 sun - 4 wind speed means: standard sunlight intensity and wind speed is 4ms -1 .

[0034] The above three comparison examples are from: Comparative Example 1: Y. Liu, B. Luo, H. Liu, M. He, R. Wang, L. Wang, Z. Quan, J.Yu, X. Qin, 3D printed electrospun nanofiber-based pyramid-shaped solar vapor generator with hierarchical porous structure for efficient desalination, Chemical Engineering Journal 452 (2023) 139402.

[0035] Comparative Example 2: Y. Chen, Y. Wang, J. Xu, MR Ibn Raihan, B. Guo, G. Yang, M.Li, H. Bao, H. Xu, A 3D Opened Hollow Photothermal Evaporator for HighlyEfficient Solar Steam Generation, Solar RRL 6(7) (2022) 2200202.

[0036] Comparative Example 3: Z. Zhang, W. Xu, J. Wang, M. Hu, D. Zhang, L. Jia, A. Kang, Y. Xi, X. Ye, S. Cheng, E. Sun, Y. Chen, Z. Wang, H. Lin, Q. Xiao, Improving Solar Vapor Generation by Eliminating the Boundary Layer Inhibition Effect of Evaporator Pores, ACS Energy Letters 8(5) (2023) 2276-2283.

[0037] The present invention effectively utilizes the dual drive of solar energy and wind energy to significantly increase the evaporation rate of the seawater evaporator, while effectively solving the problem of salt accumulation on the surface of the evaporator, greatly improving its long-term operation stability.

Claims

1. A self-floating and self-cleaning seawater evaporator driven by both solar energy and wind energy, characterized in that: It includes a self-floating support base and a water absorption and evaporation component. A mounting hole is opened at the center of the self-floating support base. The water absorption and evaporation component is penetrated at the center of the self-floating support base, and the water absorption and evaporation component is closely matched with the self-floating support base. The water absorption and evaporation component can absorb sunlight and utilize wind power to evaporate seawater, and can prevent the accumulation of salt produced by the evaporation of seawater.

2. The self-floating and self-cleaning seawater evaporator driven by both solar and wind energy according to claim 1 is characterized in that: The supporting self-floating base is made of foamed polylactic acid (PLA) material and has a hollow structure as a whole, with an inverted quadrangular pyramid being dug out from the center to form a mounting hole.

3. The self-floating and self-cleaning seawater evaporator driven by both solar and wind energy according to claim 1 is characterized in that: The water absorption and evaporation component has a density greater than that of water, so that the water absorption and evaporation component can be tightly combined with the supporting self-floating base.

4. The self-floating and self-cleaning seawater evaporator driven by both solar and wind energy according to claim 1 is characterized in that: The bottom of the water absorbing and evaporating component extends out from the floating base and is immersed in the seawater, and the top of the water absorbing and evaporating component is exposed from the floating base and is exposed to the air.

5. The self-floating and self-cleaning seawater evaporator driven by both solar and wind energy according to claim 1 is characterized in that: The water absorption and evaporation component adopts an inner and outer petal structure, including an inner petal component and an outer petal component. The inner and outer petal components are respectively V-shaped structures as a whole, and the V-shaped structure is an upper open parabola at the part below the self-floating base, and is a linear shape at the part inside the self-floating base and above the self-floating base.

6. The self-floating and self-cleaning seawater evaporator driven by both solar and wind energy according to claim 5, characterized in that: The upper opening parabola formula of the inner petal component is: ; The upper opening parabola formula of the outer petal component is: ; The straight line of the inner petal component forms an angle of 67.5 to 75° with the horizontal line, and the straight line of the outer petal component forms an angle of 45 to 67.5° with the horizontal line.

7. The self-floating and self-cleaning seawater evaporator driven by both solar and wind energy according to claim 1, characterized in that: The preparation process of the water absorption and evaporation component is as follows: Step 1) Place appropriate amounts of polyvinylidene fluoride PVDF powder and nanographite powder GNP powder in an electric heated air drying oven at 65-75°C for 25-30 minutes to remove moisture and ensure complete drying; Step 2) Add 9.5 g of dry PVDF into a beaker containing 50 ml of dimethylacetamide DMA, place the beaker in a heat-collecting constant temperature heating magnetic stirrer, and stir in a water bath at 70-80°C for 2.5-3.5 hours until the PVDF is completely dissolved to obtain a colorless and transparent PVDF solution; Step 3) Add 0.5 g of dry GNPs to the PVDF solution, continue stirring in a water bath at 70-80°C for 2.5-3.5 hours, and then take it out and perform ultrasonic dispersion for 25-30 minutes to obtain a uniformly dispersed black composite solution; then cover the solution with a breathable membrane and let it stand at room temperature for 7-9 hours to eliminate bubbles for further use; Step 4) After the defoaming process is completed, the black composite solution is injected into the mold using a syringe to completely fill it; after the mold is sealed, it is precooled in a refrigerator at about 3 to 5°C for 5 to 7 hours to prevent cracking during the actual freezing process; after precooling, the mold is placed in a cold trap of a vacuum freeze dryer and frozen at -65 to -70°C for 1.5 to 2.5 hours; Step 5) After complete freezing, the mold is disassembled to obtain a 3D solid composite; Step 6) The solid composite is placed back into the cold trap and freeze-dried at -65 to -70°C and 0.1 Pa for 2.5 to 3.5 hours to sublime the DMA solvent and form a 3D water absorption and evaporation component.

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