A photothermal interfacial evaporation seawater desalination coupled with photocatalytic hydrogen production system
By coupling a photothermal interface evaporation seawater desalination system with a photocatalytic hydrogen production system, the problems of low seawater evaporation rate, membrane fouling, and light loss in solar photothermal seawater desalination and photocatalytic hydrogen production systems have been solved, achieving efficient utilization and high-efficiency energy conversion of the full spectrum of solar energy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG JIANZHU UNIV
- Filing Date
- 2026-06-25
- Publication Date
- 2026-07-31
AI Technical Summary
In existing technologies, solar thermal seawater desalination and photocatalytic hydrogen production systems suffer from problems such as low seawater evaporation rate, membrane fouling, light loss, and poor stability of photocatalysts, and fail to effectively utilize the full spectrum of solar energy.
A photothermal interfacial evaporation seawater desalination coupled with photocatalytic hydrogen production system is adopted, which includes a light-transmitting layer, a photocatalytic aerogel layer, an interfacial evaporation layer, a hydrophobic film layer, and a capillary core layer. By dynamically adjusting the steam volume and temperature, the system achieves the synergistic utilization of infrared light seawater desalination and ultraviolet light hydrogen production, avoiding membrane fouling and light loss.
It achieves efficient utilization of the full spectrum of solar energy, improves the efficiency of seawater desalination and hydrogen production, reduces costs, and increases the photothermal energy conversion efficiency to 89%.
Smart Images
Figure CN122479683A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of solar-powered seawater desalination and solar-powered hydrogen production technology, and specifically relates to a photothermal interface evaporation seawater desalination coupled with photocatalytic hydrogen production system. Background Technology
[0002] Hydrogen energy has the characteristics of high energy density, zero carbon emissions, and renewability, making it the most ideal secondary energy source in the 21st century. Utilizing solar energy and seawater, which are inexhaustible resources, for seawater desalination and hydrogen production is an ideal way to convert solar energy into hydrogen energy at low cost, and it has important strategic significance for achieving dual security of energy and water resources.
[0003] Photocatalytic hydrogen production is one of the most promising methods for producing hydrogen from water using solar energy. However, due to the inherent band structure of semiconductor photocatalysts, the infrared light (which accounts for 54% of the solar spectrum) and part of the visible light are difficult to utilize directly and are dissipated as heat. Only ultraviolet light and part of the visible light can be utilized, resulting in low efficiency of photocatalytic hydrogen production.
[0004] Solar thermal-driven seawater desalination includes two technologies: direct and indirect methods. The indirect method involves collecting solar thermal energy at a cutoff point before seawater distillation in an evaporation unit. Due to the need for heat exchange equipment and multiple heat transfer processes, the direct method of solar seawater desalination is costly. Interfacial evaporation, a representative direct solar seawater desalination technology, shifts the evaporation process from the bulk seawater to the seawater-air interface, significantly improving the energy efficiency of photothermal evaporation. However, interfacial evaporation primarily utilizes infrared light energy, making efficient use of shorter wavelength ultraviolet light difficult. Coupled with photocatalytic hydrogen production and interfacial evaporation seawater desalination, utilizing the frequency-division utilization of the solar spectrum, can achieve seawater desalination using the photothermal effect of infrared light and hydrogen production through photocatalytic decomposition of desalinated water using ultraviolet light. This can effectively reduce the cost of both solar seawater desalination and photocatalytic hydrogen production. Therefore, developing efficient coupling systems and methods for photocatalytic hydrogen production and photothermal seawater desalination is an urgent problem to be solved to improve the synergistic conversion and utilization efficiency of the entire solar spectrum.
[0005] Chinese patent CN118441285A discloses an apparatus and method for producing hydrogen and freshwater from seawater using solar photocatalysis. It uses semiconductor materials as photocatalytic electrodes to directly decompose seawater to produce hydrogen. Seawater absorbs solar radiation in the heat exchange chamber and evaporates to generate steam. However, the bulk evaporation of seawater in the chamber has low solar energy conversion efficiency, resulting in a low seawater evaporation rate. Direct decomposition of seawater to produce hydrogen can easily cause corrosion on the surface of the photocatalyst and reduce its performance.
[0006] Chinese patent CN115973998A discloses a solar-driven photothermal seawater desalination coupled with photocatalytic hydrogen production device and method. The photothermal and photocatalytic stacked material is on the surface of the seawater solution. The water vapor generated by the photothermal reaction reacts with the photocatalyst to produce hydrogen. The steam generated by the evaporation of seawater condenses at the top of the reaction chamber. However, the photothermal and photocatalytic stacked material on the seawater surface is prone to membrane fouling caused by inorganic salts and organic matter in the seawater, which in turn leads to a decrease in the interfacial evaporation rate. The fogging caused by the condensate at the top of the reaction chamber also causes light loss, significantly reducing the utilization rate of sunlight.
[0007] Chinese patent CN118833893A discloses a photocatalytic photovoltaic hydrogen production coupled with photothermal seawater desalination system. This system utilizes gaseous water for photocatalytic hydrogen production, photovoltaic power generation for electrolysis of liquid water to produce hydrogen, and photothermal evaporation for seawater desalination. However, the stacking of the water transport layer and evaporation layer in the photothermal layer significantly increases the thermal resistance of photothermal evaporation. The water vapor generated by photothermal evaporation passes through the photovoltaic panel and reaches the catalytic layer for hydrogen production; direct contact between the steam and the photovoltaic panel can easily damage the panel. While adjusting the steam flow channel area by changing the gap between the photovoltaic panels can regulate the amount of steam produced for catalytic hydrogen production, the fixed gap prevents dynamic adjustment of the steam volume. Furthermore, direct contact between the photovoltaic panel and the seawater transport layer can easily cause corrosion, affecting the lifespan of the photovoltaic panel.
[0008] The problems with solar thermal seawater desalination for hydrogen production are as follows: 1. Solar thermal seawater desalination mainly involves the absorption and evaporation of solar radiation by the seawater in the heat exchange chamber. The low energy density of solar radiation is distributed to all liquid phases in the chamber, which cannot efficiently vaporize the seawater at the gas-liquid interface, resulting in low energy utilization efficiency of the bulk-phase heated seawater desalination.
[0009] 2. In the process of seawater desalination using solar thermal interfacial evaporation, it is difficult to solve the problem of membrane fouling caused by salts, organic matter, etc. in the insulation layer of solar thermal materials, which reduces the interfacial evaporation rate. 3. In the solar thermal interface evaporation seawater desalination process, the light loss caused by the condensation of steam at the top of the chamber is not considered, resulting in the solar-to-freshwater energy conversion efficiency being far lower than the theoretical value.
[0010] 4. Due to the high concentration of salt ions in seawater causing reduced stability and surface corrosion of photocatalysts, it is difficult to directly utilize seawater for solar thermal hydrogen production. Furthermore, the coupled system of solar thermal seawater desalination and photocatalytic hydrogen production lacks a method for adjusting the amount of steam consumed in photocatalytic hydrogen production and the amount of steam condensed from seawater evaporation. It is limited to the utilization of the full spectrum of solar energy and does not involve the synergistic utilization of infrared and visible light seawater desalination and ultraviolet photocatalytic hydrogen production. Summary of the Invention
[0011] This invention provides a photothermal interfacial evaporation seawater desalination coupled with photocatalytic hydrogen production system, which can solve the problems pointed out in the background art.
[0012] A photothermal interfacial evaporation seawater desalination coupled with photocatalytic hydrogen production system includes a seawater desalination hydrogen production coupling device, a gas-liquid separator, and a hydrogen storage device. The seawater desalination hydrogen production coupling device consists of a light-transmitting layer, a photocatalytic aerogel layer, an interface evaporation layer, a hydrophobic film layer, and a capillary core layer arranged in parallel from top to bottom. The seawater desalination hydrogen production coupling device is tilted towards the sun. The vapor gaps between the interface evaporation layer and the photocatalytic aerogel layer, and between the interface evaporation layer and the hydrophobic film layer, are 8-12 mm and 1-3 mm, respectively. The capillary core layer is tightly bonded to the hydrophobic film layer. The lower water absorption area of the interface evaporation layer is directly immersed in the seawater pool, and the lower water absorption area of the capillary core layer is directly immersed in the freshwater pool. The hydrogen space above the photocatalytic aerogel layer is sequentially connected to a gas-liquid separator and a hydrogen storage tank.
[0013] Preferably, the light-transmitting layer is light-transmitting glass.
[0014] Preferably, the interface evaporation layer is a single-layer graphene photothermal material layer.
[0015] Preferably, the vapor gaps between the interface evaporation layer and the photocatalytic aerogel layer and the hydrophobic film layer are 10 mm and 2 mm, respectively.
[0016] A photothermal multi-effect evaporation seawater desalination coupled with photovoltaic hydrogen production process includes the following steps: Step 1: Sunlight passes through the light-transmitting layer and enters the seawater desalination hydrogen production coupling device. The photocatalytic aerogel layer absorbs ultraviolet light with a wavelength of less than 400nm and produces hydrogen from part of the water vapor generated by the interface evaporation layer in the form of water vapor pyrolysis. The hydrogen containing water vapor is separated into water vapor in the gas-liquid separator and then stored in the hydrogen storage tank. Step 2: Seawater in the seawater pool forms a thin evaporation liquid film on the surface of the interfacial evaporation layer through the capillary effect of the graphene nanochannels within the interfacial evaporation layer. Visible light and infrared light with wavelengths of 400nm-1000nm pass through the porous photocatalytic aerogel layer and irradiate the interfacial evaporation layer. After the interfacial evaporation layer converts the incident light into heat energy, the surface liquid film evaporates to generate steam when the surface temperature is 45-65℃. Driven by the steam pressure difference, 10%-15% of the evaporated steam flows upward to the photocatalytic aerogel layer as a raw material for its photocatalytic hydrogen production. The remaining steam passes through the steam gap between the interfacial evaporation layer and the hydrophobic film layer and enters the hydrophobic film layer. Step 3: In the lower water absorption zone of the capillary core layer, which is closely attached to the hydrophobic membrane layer, capillary force drives the cooling fresh water in the fresh water tank to be transported upward along its internal capillary channels to the upper condensation zone of the capillary core layer; some of the steam generated by the interface evaporation is driven by the steam pressure difference on both sides of the hydrophobic membrane layer to pass through the hydrophobic membrane pores and reach the capillary core layer, where the steam is condensed into fresh water by the cooling fresh water in the capillary core layer and collected in the fresh water tank; Step 4: Based on the quantitative relationship between solar irradiance intensity and interface evaporation rate, the amount of condensed steam in the capillary core layer is dynamically adjusted by regulating the freshwater temperature in the freshwater pool, thereby dynamically adjusting the amount of steam consumed in hydrogen production in the photocatalytic aerogel layer, achieving synergistic utilization between infrared and visible light seawater desalination and ultraviolet photocatalytic hydrogen production.
[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The interfacial evaporation method was used to couple photocatalytic hydrogen production and photothermal seawater desalination, achieving efficient utilization of the full spectrum of solar energy. The photothermal effect of infrared light was used for seawater desalination, and ultraviolet light was used for photocatalytic decomposition of desalinated water to produce hydrogen.
[0018] 2. The temperature of the cooling freshwater in the freshwater pool is dynamically adjusted based on the quantitative relationship between solar irradiance intensity and interfacial evaporation rate. By rationally allocating the amount of steam for photocatalytic hydrogen production and seawater desalination condensation, the problem of light loss caused by excessive steam condensation and fogging, which exceeds the steam consumption of photocatalytic hydrogen production, is overcome. The amount of steam for photocatalytic hydrogen production and seawater desalination condensation is dynamically adjusted based on the synergistic utilization of infrared and visible light seawater desalination and ultraviolet photocatalytic hydrogen production.
[0019] 3. By adopting a single-layer structure that eliminates the need for a heat insulation layer, and a vapor gap between the interface evaporation layer and the hydrophobic film layer, the interfacial evaporation rate is improved by avoiding membrane fouling caused by inorganic salts and organic matter in seawater. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of a photothermal interfacial evaporation seawater desalination coupled with photocatalytic hydrogen production system. Figure 2 This is a cross-sectional view of a photothermal interfacial evaporation seawater desalination coupled with photocatalytic hydrogen production device. Figure 3 This is a diagram of a photothermal interfacial evaporation seawater desalination coupled with photocatalytic hydrogen production system. Figure 4 The change of evaporation flux in the interfacial evaporation layer over time; Figure 5 Photothermal evaporation energy utilization efficiency.
[0021] In the figure: 1. Seawater desalination hydrogen production coupling device, 2. Transparent layer, 3. Photocatalytic aerogel layer, 4. Interfacial evaporation layer, 5. Hydrophobic film layer, 6. Capillary core layer, 7. Seawater pool, 8. Freshwater pool, 9. Gas-liquid separator, 10. Hydrogen storage tank. Detailed Implementation
[0022] The following detailed description of a specific embodiment of the present invention is provided in conjunction with the accompanying drawings. However, it should be understood that the scope of protection of the present invention is not limited to the specific embodiment.
[0023] like Figure 1 As shown, an embodiment of the present invention provides a photothermal multi-effect evaporation seawater desalination coupled with photovoltaic hydrogen production device, including a seawater desalination hydrogen production coupling device 1, a gas-liquid separator 9, and a hydrogen storage device 10. The seawater desalination hydrogen production coupling device 1 is arranged in parallel from top to bottom as follows: a light-transmitting layer 2, a photocatalytic aerogel layer 3, an interface evaporation layer 4, a hydrophobic film layer 5, and a capillary core layer 6. The light-transmitting layer 2 is transparent glass, and the interface evaporation layer 4 is a single-layer graphene photothermal material layer. The seawater desalination hydrogen production coupling device 1 is tilted towards the sun, and the tilt angle is set according to different latitudes. The vapor gaps between the interface evaporation layer 4 and the photocatalytic aerogel layer 3 and the hydrophobic film layer 5 are 8-12 mm and 1-3 mm, respectively, and the vapor gaps are preferably 10 mm and 2 mm, respectively. The capillary core layer 6 is tightly attached to the hydrophobic film layer 5. The lower water absorption area of the interface evaporation layer 4 is directly immersed in the seawater pool 7, and the lower water absorption area of the capillary core layer 6 is directly immersed in the freshwater pool 8. The upper hydrogen space of the photocatalytic aerogel layer 3 is sequentially connected to a gas-liquid separator 9 and a hydrogen storage tank 10.
[0024] A photothermal multi-effect evaporation seawater desalination coupled with photovoltaic hydrogen production process includes the following steps: Step 1: Sunlight passes through the light-transmitting layer 2 and enters the seawater desalination hydrogen production coupling device 1. The photocatalytic aerogel layer 3 absorbs ultraviolet light with a wavelength of less than 400nm and produces hydrogen from part of the water vapor generated by the interface evaporation layer 4 in the form of cracked water vapor. The generated hydrogen containing water vapor is separated from the water vapor in the gas-liquid separator 9 and then stored in the hydrogen storage tank 10. Step 2: In seawater pool 7, a thin evaporation liquid film is formed on the surface of the interface evaporation layer 4 through the capillary effect of graphene nanochannels within the interface evaporation layer 4. Visible light and infrared light with wavelengths of 400nm-1000nm pass through the porous photocatalytic aerogel layer 3 and irradiate the interface evaporation layer 4. After the interface evaporation layer 4 converts the incident light into heat energy, the surface liquid film evaporates to generate steam when the surface temperature is 45-65℃. Driven by the steam pressure difference, 10%-15% of the evaporated steam flows upward to the photocatalytic aerogel layer 3 as the raw material for its photocatalytic hydrogen production. The remaining steam passes through the steam gap between the interface evaporation layer 4 and the hydrophobic film layer 5 and enters the hydrophobic film layer 5. The single-layer photothermal material structure of the interface evaporation layer 4 and the 1-3mm steam gap avoid membrane fouling caused by direct contact between inorganic salts, organic matter, etc. in the seawater and the hydrophobic film layer 5. Step 3: In the lower water absorption zone of the capillary core layer 6, which is tightly attached to the hydrophobic membrane layer 5, capillary force drives the cooling fresh water in the fresh water tank 8 to be transported upward along its internal capillary channels to the upper condensation zone of the capillary core layer 6; some of the steam generated by the interface evaporation is driven by the steam pressure difference on both sides of the hydrophobic membrane layer 5 to reach the capillary core layer 6 through the hydrophobic membrane pores, and the steam is condensed into fresh water by the cooling fresh water in the capillary core layer 6 and collected in the fresh water tank 8; Step 4: Based on the quantitative relationship between solar irradiance intensity and interface evaporation rate, the amount of condensed steam in the capillary core layer 6 is dynamically adjusted by regulating the freshwater temperature in the freshwater pool 8, thereby dynamically adjusting the amount of steam consumed in hydrogen production in the photocatalytic aerogel layer 3, achieving synergistic utilization between infrared and visible light seawater desalination and ultraviolet photocatalytic hydrogen production.
[0025] Taking into account that the solar energy conversion efficiency of photocatalytic hydrogen production using ultraviolet light can be increased to 89%, it effectively improves the energy conversion efficiency of solar thermal energy and reduces the cost of solar seawater desalination for hydrogen and freshwater production.
[0026] In the existing experiments on photothermal interfacial evaporation seawater desalination coupled with photocatalytic hydrogen production, the change of seawater evaporation flux in the interfacial evaporation layer over time is as follows: Figure 4 As shown, the seawater evaporation rate increases linearly with time, indicating that membrane fouling did not occur during the evaporation process, thus preventing a decrease in the interfacial evaporation rate. The photothermal evaporation energy utilization efficiency is as follows: Figure 5 As shown, the energy utilization efficiency of the interface evaporation layer reaches nearly 90%.
[0027] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.
Claims
1. A photothermal multi-effect evaporation seawater desalination coupled with photovoltaic hydrogen production device, characterized in that: It includes a seawater desalination hydrogen production coupling device (1), a gas-liquid separator (9), and a hydrogen storage device (10). The seawater desalination hydrogen production coupling device (1) is arranged in parallel from top to bottom as follows: a light-transmitting layer (2), a photocatalytic aerogel layer (3), an interface evaporation layer (4), a hydrophobic film layer (5), and a capillary core layer (6). The seawater desalination hydrogen production coupling device (1) is tilted towards the sun. The vapor gaps between the interface evaporation layer (4) and the photocatalytic aerogel layer (3) and the hydrophobic film layer (5) are 8-12 mm and 1-3 mm, respectively. The capillary core layer (6) is tightly attached to the hydrophobic film layer (5). The lower water absorption area of the interface evaporation layer (4) is directly immersed in the seawater pool (7). The lower water absorption area of the capillary core layer (6) is directly immersed in the freshwater pool (8). The upper hydrogen space of the photocatalytic aerogel layer (3) is connected to a gas-liquid separator (9) and a hydrogen storage tank (10).
2. The photothermal multi-effect evaporation seawater desalination coupled with photovoltaic hydrogen production device and process according to claim 1, characterized in that: The light-transmitting layer (2) is light-transmitting glass.
3. The photothermal multi-effect evaporation seawater desalination coupled with photovoltaic hydrogen production device and process according to claim 1, characterized in that: The interface evaporation layer (4) is a single-layer graphene photothermal material layer.
4. The photothermal multi-effect evaporation seawater desalination coupled with photovoltaic hydrogen production device and process according to claim 1, characterized in that: The vapor gaps between the interface evaporation layer (4) and the photocatalytic aerogel layer (3) and the hydrophobic film layer (5) are 10 mm and 2 mm, respectively.
5. A photothermal multi-effect evaporation seawater desalination coupled with photovoltaic hydrogen production process, characterized in that, Includes the following steps: Step 1: Sunlight enters the seawater desalination hydrogen production coupling device (1) through the light-transmitting layer (2). The photocatalytic aerogel layer (3) absorbs ultraviolet light with a wavelength of less than 400nm and produces hydrogen from part of the water vapor generated by the interface evaporation layer (4) in the form of cracked water vapor. The generated hydrogen containing water vapor is separated into water vapor in the gas-liquid separator (9) and then stored in the hydrogen storage tank (10). Step 2: In the seawater pool (7), the graphene nanochannels in the interface evaporation layer (4) form a thin evaporation liquid film on the surface of the interface evaporation layer (4) through capillary effect. Visible light and infrared light with wavelengths of 400nm-1000nm pass through the porous photocatalytic aerogel layer (3) and irradiate the interface evaporation layer (4). After the interface evaporation layer (4) converts the incident light into heat energy, the surface liquid film evaporates to generate steam when the surface temperature is 45-65℃. Driven by the steam pressure difference, 10%-15% of the evaporated steam flows upward to the photocatalytic aerogel layer (3) as the raw material for its photocatalytic hydrogen production. The remaining steam passes through the steam gap between the interface evaporation layer (4) and the hydrophobic film layer (5) and enters the hydrophobic film layer (5). Step 3: In the lower water absorption zone of the capillary core layer (6) which is closely attached to the hydrophobic membrane layer (5), the capillary force drives the cooling fresh water in the fresh water tank (8) to be transported upward along its internal capillary channels to the upper condensation zone of the capillary core layer (6); some of the steam generated by the interface evaporation is driven by the steam pressure difference on both sides of the hydrophobic membrane layer (5) to reach the capillary core layer (6) through the hydrophobic membrane pores, and the steam is condensed into fresh water by the cooling fresh water in the capillary core layer (6) and collected in the fresh water tank (8); Step 4: Based on the quantitative relationship between solar irradiance intensity and interface evaporation rate, the amount of condensed steam in the capillary core layer (6) is dynamically adjusted by adjusting the freshwater temperature in the freshwater pool (8), thereby dynamically adjusting the amount of steam consumed in hydrogen production in the photocatalytic aerogel layer (3), so as to achieve synergistic utilization between infrared and visible light seawater desalination and ultraviolet photocatalytic hydrogen production.