阅读说明：本技术 一种基于亲水性碳毡的光热转化器件及其应用 (Photo-thermal conversion device based on hydrophilic carbon felt and application thereof ) 是由 成少安 于祯 于 2019-08-19 设计创作，主要内容包括：本发明涉及光热转化技术领域,旨在提供一种基于亲水性碳毡的光热转化器件及其应用。该光热转化器件包括顶部吸收体、中部的水传输体,以及能漂浮在液体表面的底部绝热支撑体；在绝热支撑体上间隔设有若干个竖向孔道；在各孔道中插有水传输体,水传输体的两端伸出绝热支撑体的上下表面,且上段直接暴露在空气中；顶部吸收体是片状的亲水性碳毡片,自然放置在各水传输体的顶端并实现支承。本发明中的绝热支撑体热阻较大,避免了顶部吸收体从阳光中获取的热量向下传递,整个器件的热效率较高。水传输体上段的微纳米孔道与空气界面直接接触,具有更高的饱和蒸气压；水分在挥发的同时会冷却整个器件,可从环境中获取热量,更接近热力学蒸发极限。(The invention relates to the technical field of photothermal conversion, and aims to provide a photothermal conversion device based on a hydrophilic carbon felt and application thereof. The photothermal conversion device comprises a top absorber, a water transmission body in the middle and a bottom heat insulation support body capable of floating on the liquid surface; a plurality of vertical pore channels are arranged on the heat insulation support body at intervals; the water transmission body is inserted into each pore channel, two ends of the water transmission body extend out of the upper surface and the lower surface of the heat insulation support body, and the upper section of the water transmission body is directly exposed in the air; the top absorber is a hydrophilic carbon mat in sheet form that naturally rests on top of and provides support for each water conductor. The heat insulation support body has larger heat resistance, avoids the downward transmission of heat acquired by the top absorber from sunlight, and has higher heat efficiency of the whole device. The micro-nano pore channel on the upper section of the water transmission body is directly contacted with an air interface, so that the water transmission body has higher saturated vapor pressure; the moisture cools the whole device while volatilizing, and heat can be obtained from the environment, and the thermodynamic evaporation limit is more approached.)

1. A photo-thermal conversion device based on hydrophilic carbon felt comprises a top absorber, a middle water transmission body and a bottom heat insulation support body which can float on the surface of a liquid; it is characterized in that a plurality of vertical pore canals are arranged on the heat insulation supporting body at intervals; the water transmission body is inserted into each pore channel, two ends of the water transmission body extend out of the upper surface and the lower surface of the heat insulation support body, and the upper section of the water transmission body is directly exposed in the air; the top absorber is a hydrophilic carbon mat in sheet form that naturally rests on top of and provides support for each water conductor.

2. The photothermal conversion device according to claim 1, wherein said hydrophilic carbon mat has a radius of 3.5cm and a thickness of 1 cm; the heat insulation support body is in a sheet shape, the radius of the heat insulation support body is 3.5cm, and the thickness of the heat insulation support body is 1 cm; the water transmission body is cylindrical, the radius of the water transmission body is 3mm, the length of the water transmission body is 3-7 cm, and the length of the water transmission body exposed out of the upper surface of the heat insulation support body is 1-4 cm.

3. The photothermal conversion device according to claim 1, wherein said hydrophilic carbon mat has a surface contact angle of 60.1 ° to 2.1 °, and is prepared by: placing the carbon felt in deionized water, and ultrasonically cleaning for 30 min; drying, placing in a reaction container, and adding a concentrated nitric acid solution with the mass concentration of 60% to completely immerse the carbon felt; sealing the reaction container, and heating in a water bath at the temperature of 80 ℃ for 2-6 h; cooling to room temperature, repeatedly washing with water to neutrality, and drying in an oven at 60 deg.C to obtain hydrophilic carbon felt; and then cutting according to the required size to obtain the hydrophilic carbon felt.

4. The photothermal conversion device according to claim 1, wherein said water transporting body is cylindrical and is any one of a felt strip, a sponge bar, a foam or a filter paper bar; wherein the felt strips are formed by rolling the hydrophilic carbon felt or the carbon cloth.

5. The photothermal conversion device according to claim 1, wherein the length of the upper portion of the water transport body directly exposed to the air is 30 to 60% of the total length thereof.

6. The photothermal conversion device according to claim 1, wherein said heat insulating support is in the form of a sheet, and is obtained by cutting and punching any one of the following materials: foamed polyethylene, foamed polyvinyl chloride, foamed polypropylene ethylene, fibers, or aerogels.

7. The water evaporation and collection apparatus for a photothermal conversion device according to any one of claims 1 to 6, wherein the water evaporation and collection apparatus comprises a first water tank for containing a liquid to be treated, and an upper portion of the first water tank is sealed by a side wall and a light-transmitting top plate; an exhaust fan is arranged on the side wall, a second water tank for collecting condensed water is arranged on the outer edge of the exhaust fan, and a cooling fin and a water outlet are arranged in the second water tank; the first water tank is connected with a water inlet, and the photothermal conversion device is arranged in the first water tank; when the first trough is filled with liquid, the light-to-heat conversion device can float on the surface of the liquid and make the top absorber receive sunlight from the light-transmitting top plate.

8. The moisture evaporation and collection apparatus of claim 7, wherein a slantingly upward cover having an open groove is provided on a surface of the first water tank, the photothermal conversion device being located in the open groove; a drain hole is arranged on the side wall of the lower end of the inclined upper cover and connected to the second water tank; the exhaust fan is positioned above the drain hole.

9. The apparatus for evaporation and collection of water according to claim 7, wherein said light-transmissive top plate is obliquely disposed and is one of a light-transmissive plate and a light-transmissive film.

10. Use of the water evaporation and collection apparatus of claim 7 as a solar seawater desalination plant, a solar sewage treatment plant, a solar solution purification plant, a solar solution concentration plant or a solar oil-water separation plant.

Technical Field

The invention relates to the field of photo-thermal conversion, in particular to a photo-thermal conversion device based on a hydrophilic carbon felt and application thereof.

background

With the gradual shortage of fresh water resources and the increasing severity of water pollution, a water treatment technology which is efficient, low-toxicity, cheap and environment-friendly is particularly critical. The solar water evaporation technology is favored by numerous scholars by virtue of the advantages of low energy consumption, no secondary pollution, high purity of the obtained fresh water and the like. However, the conventional solar water evaporator generally depends on a complex and large light gathering or tracking device, which is greatly influenced by weather, difficult in later maintenance, high in cost and large in heat loss, and is not suitable for large-scale industrial application.

In order to improve the evaporation performance of the solar water evaporator, the solar water evaporator which takes the interface photothermal conversion device as a core working module is produced. The device is a typical double-layer structure and is composed of a top absorber and a bottom suspensible heat-insulating support body, and the interior of the device is rich in water transmission channels. However, the main obstacles for the application of this device are: (1) there is a lack of an effective photothermal conversion material as a top absorber. Reported photothermal conversion materials such as carbon nanotubes, graphene, semiconductor sulfides, noble metal materials and the like have great problems in current research and future applications, such as complex preparation process, high cost and certain toxicity. The absorber has higher temperature under illumination and lower ambient temperature, so the device still has larger convection loss and radiation loss, and the heat on the surface of the absorber can still be transferred into water under the condition of long-time operation, thereby causing certain heat conduction loss. (2) The water transfer channel of the solar water evaporator is positioned inside the heat insulation support body, so that the evaporation effect is poor.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects in the prior art and provides a photo-thermal conversion device based on a hydrophilic carbon felt and application thereof.

In order to solve the technical problem, the solution of the invention is as follows:

Providing a photo-thermal conversion device based on a hydrophilic carbon felt, which comprises a top absorber, a middle water transmission body and a bottom heat insulation support body capable of floating on the surface of a liquid; a plurality of vertical pore channels are arranged on the heat insulation support body at intervals; the water transmission body is inserted into each pore channel, two ends of the water transmission body extend out of the upper surface and the lower surface of the heat insulation support body, and the upper section of the water transmission body is directly exposed in the air; the top absorber is a hydrophilic carbon mat in sheet form that naturally rests on top of and provides support for each water conductor.

In the invention, the radius of the hydrophilic carbon felt is 3.5cm, and the thickness of the hydrophilic carbon felt is 1 cm; the heat insulation support body is in a sheet shape, the radius of the heat insulation support body is 3.5cm, and the thickness of the heat insulation support body is 1 cm; the water transmission body is cylindrical, the radius of the water transmission body is 3mm, the length of the water transmission body is 3-7 cm, and the length of the water transmission body exposed out of the upper surface of the heat insulation support body is 1-4 cm.

In the invention, the surface contact angle of the hydrophilic carbon felt is 60.1-2.1 degrees, and the hydrophilic carbon felt is prepared by the following method:

Placing the carbon felt in deionized water, and ultrasonically cleaning for 30 min; drying, placing in a reaction container, and adding a concentrated nitric acid solution with the mass concentration of 60% to completely immerse the carbon felt; sealing the reaction container, and heating in a water bath at the temperature of 80 ℃ for 2-6 h; cooling to room temperature, repeatedly washing with water to neutrality, and drying in an oven at 60 deg.C to obtain hydrophilic carbon felt; and then cutting according to the required size to obtain the hydrophilic carbon felt.

In the invention, the water transmission body is cylindrical and is any one of a felt strip, a sponge body, a sponge rod, foam or a filter paper rod; wherein the felt strips are formed by rolling the hydrophilic carbon felt or the carbon cloth.

In the invention, the length of the upper section of the water transmission body directly exposed in the air accounts for 30-60% of the total length of the water transmission body.

In the present invention, the heat insulating support is in the form of a sheet, and can be made by cutting and punching any one of the following materials: foamed polyethylene, foamed polyvinyl chloride, foamed polypropylene ethylene, fibers, or aerogels.

The invention further provides a water evaporation and collection device based on the photothermal conversion device, which comprises a first water tank for containing liquid to be treated, wherein the upper part of the first water tank is sealed by a side wall and a light-transmitting top plate; an exhaust fan is arranged on the side wall, a second water tank for collecting condensed water is arranged on the outer edge of the exhaust fan, and a cooling fin and a water outlet are arranged in the second water tank; the first water tank is connected with a water inlet, and the photothermal conversion device is arranged in the first water tank; when the first trough is filled with liquid, the light-to-heat conversion device can float on the surface of the liquid and make the top absorber receive sunlight from the light-transmitting top plate.

In the invention, an inclined upward cover with an open slot is arranged on the surface of a first water tank, and the photothermal conversion device is positioned in the open slot; a drain hole is arranged on the side wall of the lower end of the inclined upper cover and connected to the second water tank; the exhaust fan is positioned above the drain hole.

In the invention, the light-transmitting top plate is obliquely arranged and is any one of a light-transmitting plate or a light-transmitting film.

The invention also provides application of the water evaporation and collection equipment as a solar seawater desalination device, a solar sewage treatment device, a solar solution purification device, a solar solution concentration device or a solar oil-water separation device.

Description of the inventive principles:

(1) Surface hydrophilization of shaped carbon materials

According to the invention, a large number of oxygen-containing functional groups are introduced on the surface of a commercially available carbon felt or carbon cloth through the strong oxidation of concentrated nitric acid, and the functional groups endow the surface of the carbon felt with extremely strong hydrophilicity.

The reported methods for surface hydrophilic treatment can be divided into coating with hydrophilic coating, grafting hydrophilic polymer, etc. The hydrophilic coating is easy to be lost after multiple cycles, so that the hydrophilicity of the surface of the material is reduced; in addition, the procedure for grafting hydrophilic polymers is complicated, and toxic organic substances are introduced to some extent. In addition, these two common methods of surface hydrophilic treatment may result in a decrease in the surface spectral absorbance of the absorber. Compared with the technology, the surface hydrophilic treatment method has the advantages of simple operation, low cost, low energy consumption, high cycle stability, batch production and the like.

(2) Efficient photo-thermal conversion device constructed by hydrophilic carbon felt

The photothermal conversion device belongs to an interfacial water evaporation device, and an absorber of the device is a carbon felt which has high optical absorption rate, low cost and environmental friendliness; the middle is the upper section of the water transmission body directly exposed in the air, and the heat insulation support body at the bottom is polystyrene foam which can be suspended in the water. The absorber has high optical absorption rate, and can rapidly increase the temperature under low optical concentration; the bottom of the device has high thermal resistance, so that the heat of the absorber cannot be effectively transferred downwards and is concentrated on the surface of the absorber. The water from the bottom rapidly reaches the upper surface of the device through the water transport channels under capillary action. Because the saturated vapor pressure of water at the gas-liquid interface is larger, evaporation can be realized at a lower temperature (room temperature), and the device can realize a higher evaporation rate.

compared with the prior art, the invention has the beneficial effects that:

1. In the present invention, the evaporation process only occurs at the gas-liquid two-phase interface. Because the mass transfer speed of the photothermal conversion device is large enough and is influenced by the special physical properties of the gas-liquid interface, water existing in the interface can be evaporated continuously without reaching the boiling point.

2. The heat insulation support body has larger heat resistance, and avoids the downward transfer of heat acquired by the top absorber from sunlight. Since the heat is concentrated only on the surface of the top absorber, the thermal efficiency of the entire device is high. The spectral absorption of the top absorber in the full spectrum sunlight (2500 nm-500 nm) was measured to be 80% to 100%.

3. The upper section of the water transmission body exposed out of the heat insulation support body is exposed in the air, and the micro-nano pore channel of the water transmission body is in direct contact with the air interface, so that the water transmission body has higher saturated vapor pressure, the average saturated vapor pressure of the whole device is higher, and water is easier to evaporate under the same condition.

4. The upper section of the water transport body is directly exposed to air, and the water can cool the whole device while volatilizing, so that the average temperature of the device is lower than the ambient temperature, and the photothermal conversion device can obtain heat from the environment, thereby being closer to the thermodynamic evaporation limit.

Drawings

FIG. 1 is a schematic view of a photothermal conversion device according to the present invention;

fig. 2 is a schematic view of a seawater desalination apparatus including a photothermal conversion device in embodiment 3 of the present invention.

Reference numbers in the figures: a solar seawater desalination plant 1; a photothermal conversion device 2; a first water tank 3; an exhaust fan 4; a second water tank 5; a light-transmitting top plate 6; a cooling fin 7; a water inlet 8; a water outlet 9; a thermally insulating support body 10; a water conveyance body 11; a top absorbent body 12.

Detailed Description

The features of the invention will be described below with reference to the accompanying drawings and specific embodiments. It should be noted, however, that the illustrated examples are only for illustrating the present invention and are not intended to limit the scope of the present invention.