Heat pipe type seawater desalination device and seawater desalination method

Abstract

The invention belongs to the technical field of seawater desalination, and particularly relates to a heat pipe type seawater desalination device and a seawater desalination method. A base body of the heat pipe type seawater desalination device is of a closed pipeline structure and is communicated with the outside through an outlet or a pipeline arranged at the bottom, a condensation assembly is arranged outside the base body through a support structure, and seawater desalination and collection processes are completed in the base body. The whole heat pipe type seawater desalination device is divided into an evaporation section, a connection section and a condensation section from top to bottom.

Description

Technical Field

[0001] The invention belongs to the technical field of seawater desalination, and in particular relates to a heat pipe type seawater desalination device and a seawater desalination method. Background Art

[0002] There is a severe energy crisis and fresh water shortage problem in the world. Seawater desalination is a sustainable technology to obtain fresh water from seawater or brackish water. The development of seawater desalination technology is expected to solve the fresh water crisis. Current seawater desalination technologies include thermal distillation, reverse osmosis membrane and electrodialysis. These technologies generally have the problems of high energy consumption and high pollution during operation. Therefore, it is necessary to propose a new low-carbon and green seawater desalination technology.

[0003] Interfacial photothermal evaporation technology is a near-zero energy consumption desalination technology that has emerged in recent years. The principle of this technology is to use photothermal conversion materials to convert sunlight into heat energy for evaporating seawater, and set up condensation components to collect the steam generated by evaporation to obtain fresh water. This technology can be efficiently utilized in the thin water layer at the air-water interface through photothermal conversion, and has great application potential and prospects in the field of solar desalination. However, this technology is currently restricted by the energy density of the input sunlight. The low energy density of the input sunlight will lead to a low photothermal evaporation rate. In addition, the low rate of the steam-fresh water conversion process will further make it difficult for the actual water production rate to meet the application. Therefore, improving the energy input quality of the desalination device and optimizing the heat-mass conversion efficiency are the keys to achieving high-throughput desalination.

[0004] The patent with application number CN202010664522.7 and invention name "A heat pipe capillary driven small seawater desalination" discloses a device that improves the efficiency and output of seawater desalination by spraying unevaporated seawater in multiple cycles. The device has a complex structure, and the device mainly uses heat collecting plates and electric heating plates to collect heat, and transfers heat to the heat sink type turbulent evaporator through heat transfer pipes to evaporate seawater. The heat is easily lost during the pipeline transmission process, and the device cannot solve the problem of low light energy density at the source.

[0005] In summary, it is necessary to propose a new seawater desalination device to alleviate the problem of low photothermal evaporation efficiency caused by low light energy density in the prior art. Summary of the invention

[0006] In view of this, the object of the present invention is to provide a heat pipe seawater desalination device and a seawater desalination method, and the specific technical scheme is as follows.

[0007] A heat pipe type seawater desalination device, wherein the base of the heat pipe type seawater desalination device is a closed pipe structure, which is connected to the outside through an outlet or a pipe arranged at the bottom, and a focusing component is arranged outside the base through a bracket structure, and the seawater desalination and collection process is completed in the base; the heat pipe type seawater desalination device is divided into an evaporation section, a connection section and a condensation section from top to bottom;

[0008] The evaporation section includes a focusing module and a seawater desalination module; the focusing module includes at least two groups of angle-adjustable focusing plates, which are connected to the base of the heat pipe type seawater desalination device through a bracket (the angle of the focusing plates is flexibly adjustable); the seawater desalination module is provided with a double-layer vacuum heat collecting tube, a water absorption evaporation layer and a water-proof breathable film in sequence from the outside to the inside; the inner layer of the double-layer vacuum heat collecting tube is coated with a light absorbing material at one end close to the water absorption evaporation layer.

[0009] The connecting section serves as a connecting component for connecting and sealing the evaporation section and the condensation section.

[0010] The condensation section is formed by a nested double-layer pipe structure, and the nested pipe structure forms two inner and outer chambers as independent condensing water chambers and cooling water chambers. A pipe and an outlet are arranged at the bottom to communicate with the outside.

[0011] Furthermore, the vacuum collector tube is a double-layer vacuum glass tubular structure with a closed top (to reduce environmental heat dissipation); a light absorbing material is coated on one end of the inner glass side wall close to the water absorbing evaporation layer to receive the solar energy absorbed by the concentrating plate and convert it into heat energy.

[0012] Furthermore, the light absorbing material is a gradient aluminum-nitrogen composite coating; the coating thickness is 0.1-0.3 μm and the area is 0.10-1.0 m 2 .

[0013] Furthermore, the water absorption and evaporation layer is arranged on the inner side of the vacuum heat collecting tube; the water absorption and evaporation layer has a thickness of 1-3 mm and an area of ​​0.1-1.0 m 2 Porous carbon felt material.

[0014] Furthermore, the water-proof and breathable membrane is arranged on the inner side of the water-absorbing and evaporating layer facing the inside of the heat pipe type seawater desalination device substrate, and the size of the water-proof and breathable membrane matches the water-absorbing and evaporating layer, and is used to isolate seawater and allow water vapor to pass through.

[0015] Furthermore, the material of the water-proof and breathable membrane is polytetrafluoroethylene; the material of the connecting section is polytetrafluoroethylene (which has good thermal stability and thermal insulation, and is easy to process).

[0016] Furthermore, in the double-layer pipe structure of the condensation section, the inner layer is a copper tube and the outer layer is an acrylic tube; the hollow structure sandwiched in the middle of the double-layer pipe structure forms a cooling water cavity, and a cooling water inlet and outlet are arranged at the bottom; the inner copper tube forms a condensation water cavity for loading the fresh water generated by the evaporation section.

[0017] Furthermore, a fresh water outlet is provided at the bottom of the condensation water chamber; a pipeline for conveying seawater is connected to the middle of the double-layer pipeline structure, and the other end of the pipeline is connected to the water absorption and evaporation layer.

[0018] A method for desalinating seawater using the above-mentioned heat pipe type seawater desalination device comprises the following steps:

[0019] S01: placing the heat pipe seawater desalination device outdoors in a place with sufficient sunshine;

[0020] S02: Seawater is pumped in through the pipeline at the bottom of the heat pipe desalination device;

[0021] S03: Seawater enters the water absorption and evaporation layer of the heat pipe desalination device through a pipeline, and the porous carbon felt material of the water absorption and evaporation layer fully absorbs the seawater by its own capillary force and is always in a state of saturated absorption of seawater;

[0022] S04: The concentrating plate outside the base of the heat pipe desalination device and the light absorbing material coated in the double-layer vacuum heat collecting tube inside the base cooperate to absorb and amplify solar energy, converting solar energy into heat energy, so that the seawater adsorbed in the water absorption and evaporation layer in S03 evaporates to generate water vapor and enters the base of the heat pipe desalination device through the waterproof and breathable membrane;

[0023] S05: cold water is further introduced into the cooling water chamber of the heat pipe desalination device. The water vapor generated in S04 is driven by the temperature difference between the evaporation section and the condensation section to become condensed fresh water, which falls into the condensation water chamber of the heat pipe desalination device and is collected from the fresh water outlet. Generally, condensed fresh water is generated after pumping in seawater for about 10 minutes.

[0024] Furthermore, the light absorption rate of the light absorbing material is 0.98; the thermal conductivity of the evaporating material is 0.09-0.13wm -1 k -1 .

[0025] Beneficial technical effects

[0026] 1) The present invention provides a desalination / condensation integrated device with a simple and compact structure. The device utilizes the effective coupling of photothermal desalination and heat pipe technology, effectively realizes the concentration of sunlight through a butterfly-shaped concentrator, and adopts a heat pipe structure to reduce heat dissipation, thereby realizing high-throughput desalination of seawater.

[0027] 2) In the heat pipe desalination device proposed in the present invention, the coordinated use of the focusing assembly and the vacuum collector tube effectively improves the input of the solar energy flux density, that is, the density of the source solar energy is amplified, and the evaporation and desalination efficiency of seawater in the water absorption and evaporation layer is improved.

[0028] 3) In the heat pipe seawater desalination device proposed in the present invention, a waterproof breathable membrane and a double-layer vacuum collector tube are used to cleverly separate the fresh water production port from the light absorption port. Therefore, the fresh water produced by the device will not adhere to the light absorption port to affect the working efficiency of this part of the component. Therefore, the light-to-heat conversion capacity of the device will not decrease after long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale. Obviously, the drawings described below are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without paying creative labor.

[0030] Summary of reference numerals:

[0031] Evaporation section 100, connection section 200, condensation section 300, peristaltic pump 400, focusing module 110, first focusing plate 111, second focusing plate 112, bracket 113, seawater desalination module 120, vacuum collector tube 130, light absorbing material 131, water absorbing evaporation layer 140, waterproof breathable membrane 150, outer tube 310, inner tube 311, cooling water chamber 320, cooling water inlet and outlet 321, condensation water chamber 330, fresh water outlet 331.

[0032] Figure 1 A schematic cross-sectional view of the overall structure of a heat pipe type photothermal seawater desalination device provided in an embodiment of the present invention;

[0033] Figure 2 This is a real picture of the outdoor test of the prototype of the heat pipe solar thermal desalination device;

[0034] Figure 3 This is a physical picture of the heat pipe solar thermal desalination device;

[0035] Figure 4 Accumulate water production data for a heat pipe solar thermal desalination device in one of the embodiments;

[0036] Figure 5 The hourly water production rate data of the heat pipe seawater desalination device in one of the embodiments;

[0037] Figure 6 Schematic diagram of a conventional interface evaporation device used as a control in one of the embodiments. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0039] Herein "and / or" includes any and all combinations of one or more of the associated listed items.

[0040] Herein, "plurality" means two or more than two, ie, it includes two, three, four, five, etc.

[0041] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0042] As used in this specification, the term "about" typically means + / - 5% of the stated value, more typically + / - 4% of the stated value, more typically + / - 3% of the stated value, more typically + / - 2% of the stated value, even more typically + / - 1% of the stated value, and even more typically + / - 0.5% of the stated value.

[0043] In this specification, some embodiments may be disclosed in a format of being within a certain range. It should be understood that such description of "being within a certain range" is only for convenience and brevity, and should not be interpreted as a rigid limitation on the disclosed range. Therefore, the description of the range should be considered to have specifically disclosed all possible sub-ranges and independent numerical values ​​within this range. For example, the range The description of should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within this range, for example, 1, 2, 3, 4, 5, and 6. The above rules apply regardless of the breadth of the range.

[0044] Example 1

[0045] This embodiment provides a structural example of a heat pipe type seawater desalination device

[0046] A heat pipe type seawater desalination device, the base part of which is a closed pipe structure, connected to the outside through an outlet or pipe arranged at the bottom; the device as a whole is divided into an evaporation section 100, a connection section 200 and a condensation section 300 from top to bottom.

[0047] The evaporation section 100 includes a light collecting module 110 and a seawater desalination module 120; the light collecting module 110 includes at least two groups of light collecting plates (a first light collecting plate 111 and a second light collecting plate 112), which are symmetrically connected to the base of the heat pipe type seawater desalination device through a bracket 113. According to actual needs, more than two groups of light collecting plates can be set. The seawater desalination module 120 is sequentially provided with a vacuum heat collecting pipe 130, a water absorbing evaporation layer 140 and a water-proof breathable membrane 150 from the outside to the inside.

[0048] The vacuum heat collecting tube 130 is a double-layer vacuum glass tubular structure with a closed top; a light absorbing material 131 is coated on one end of the inner glass side wall close to the water absorbing and evaporating layer material 140 to receive the solar energy absorbed by the first concentrator plate 111 and the second concentrator plate 112 and convert it into heat energy. The light absorbing material 131 of the double-layer glass structure of the vacuum heat collecting tube 130 can concentrate solar energy. In addition, the double-layer glass reduces environmental heat dissipation, increases the source light energy flux density, and thus increases the rate of conversion of water vapor generation.

[0049] The water absorbing evaporation layer 140 is disposed on the inner side of the vacuum heat collecting tube 130 and is close to the light absorbing material 131 , so as to improve the thermal energy conversion efficiency.

[0050] The water-proof and breathable membrane 150 is disposed on the inner side of the water-absorbing and evaporating layer 140 and faces the inside of the device substrate. The size of the water-proof and breathable membrane 150 matches that of the water-absorbing and evaporating layer 140 and is used to isolate seawater and allow water vapor to pass through.

[0051] The connecting section 200 is used as a connecting component for connecting and sealing the evaporation section 100 and the condensation section 300 .

[0052] The bottom of the condensation section 300 is provided with a pipeline and an outlet to communicate with the outside.

[0053] Among them, the condensation section 300 is mainly composed of a double-layer pipe structure (the outer layer pipe 310 is made of acrylic; the inner layer pipe 311 is made of copper pipe), and the hollow structure sandwiched between the two layers of pipes forms a cooling water chamber 320, and a cooling water inlet and outlet 321 is set at the bottom; the inner layer pipe forms a condensation water chamber 330.

[0054] The condensed water chamber 330 is used to carry the fresh water obtained by evaporation and purification of the seawater desalination module, and a fresh water outlet 331 is provided at the bottom thereof. A pipeline for conveying seawater is connected to the middle of the double-layer pipeline structure, and the other end of the pipeline is connected to the water absorption and evaporation layer 140. Optionally, a peristaltic pump 400 can be connected to the end where the seawater enters the pipeline.

[0055] As a preferred embodiment, the material used for the water absorption and evaporation layer 140 of this embodiment is a porous carbon felt material, and the optional material includes the SMZ5MM model produced by Beihai Carbon Company, and the specific surface area thereof is 400 to 1350 g m -2 , the carbon content is about 98%, and the thermal conductivity is 0.09~0.13wm -1 k -1 .

[0056] As a preference, the vacuum heat collecting tube 130 used in this embodiment may optionally include the model zk42000292 produced by Nozhi Company; the light absorbing material 131 may optionally be a gradient aluminum-nitrogen composite coating with a light absorption rate of 0.98.

[0057] Example 2

[0058] This embodiment provides a specific example of a heat pipe seawater desalination method.

[0059] The method for desalination of seawater is implemented based on the device of Example 1, and the specific steps are as follows:

[0060] S01: placing the heat pipe desalination device outdoors in an unobstructed and sunny place;

[0061] S02: Seawater is pumped in through the pipeline at the bottom of the heat pipe desalination device;

[0062] S03: The seawater is pumped into the water absorption and evaporation layer 140 of the heat pipe desalination device through a peristaltic pump, and the pumping flow rate of the seawater is controlled at 10-20 ml min -1 The porous carbon felt material in the water absorption and evaporation layer 140 fully absorbs the seawater by its own capillary force and is always in a state of saturated absorption of seawater;

[0063] S04: Adjust the angle of the concentrator to ensure that it faces the sun. The concentrators 111 and 112 of the heat pipe desalination device and the light absorbing material 131 coated inside the double-layer vacuum heat collecting tube 130 cooperate to absorb and amplify solar energy, and efficiently convert solar energy into heat energy, so that the seawater adsorbed in the porous carbon felt in S03 evaporates to generate water vapor and enters the inside of the device base through the waterproof and breathable membrane 150;

[0064] S05: cold water is further introduced into the cooling water chamber 320 of the heat pipe desalination device (through the cooling water inlet and outlet 321), and the water vapor generated in S04 is driven by the temperature difference between the evaporation section 100 and the condensation section 300 to become condensed fresh water and fall into the condensation water chamber 330 below, and is collected from the fresh water outlet 331, completing the whole seawater desalination and collection process. Generally, condensed fresh water is generated after pumping in seawater for about 10 minutes.

[0065] In this embodiment, the coating thickness of the light absorbing material 131 is 0.1 μm and the coating area is 0.13 m 2 .

[0066] In this embodiment, the thickness of the water absorbing and evaporating layer 140 is 2 mm and the area is 0.1 m 2 .

[0067] Experimental Results

[0068] Table 1 Cumulative water production data time <![CDATA[Cumulative water production rate / L m -2 > <![CDATA[Solar irradiance / W m -2 > 10:00 3.41 579.5 12:00 12.05 842.4 14:00 22.64 889.2 16:00 32.12 674.5 18:00 38.95 362.6

[0069] Table 2 Hourly water production rate data time <![CDATA[Using condensate / W m -2 > <![CDATA[Without condensed water / W m -2 > 10:00 1.94 3.41 12:00 2.68 4.52 14:00 2.84 5.57 16:00 2.12 4.31 18:00 1.41 3.12

[0070] Experimental conclusion: See the experimental diagram Figure 4 and Figure 5 The device and method of this embodiment are used to desalinate seawater outdoors in sunny weather with no obstruction, and the fresh water output is 3.2-5.5 L m -2 h -1 .

[0071] Example 3

[0072] Conventional interface evaporation desalination technology is a process in which photothermal evaporation materials directly absorb sunlight, generate heat through photothermal conversion, and heat the seawater at the evaporation interface to produce water vapor. In addition, the fresh water produced by evaporation will adhere to the condensation cover and fall into the fresh water collection area below under the action of gravity. The more fresh water adheres to the condensation cover, the more it will affect the absorption efficiency of sunlight. This technical process is as follows Figure 6 As shown in the figure. Due to the low density of solar energy flux, the photothermal evaporation rate of evaporation materials is usually around 1.4 kg m -2 h -1 The actual freshwater yield is also less than 1 L m -2 h -1 In contrast, the heat pipe desalination technology proposed in this invention effectively improves the input of solar energy flux density through the use of focusing and vacuum collector tubes, further improves the evaporation rate of evaporation materials, and realizes efficient condensation of water vapor through the condensation component, thereby finally obtaining 3.2-5.5L m -2h -1 fresh water yield.

[0073] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A heat pipe seawater desalination device, characterized in that: The heat pipe desalination device base is a closed pipe structure, which is connected to the outside through an outlet or a pipe arranged at the bottom. A focusing component is arranged outside the base through a bracket structure, and the desalination and collection process of seawater is completed in the base. The heat pipe desalination device is divided into an evaporation section, a connection section and a condensation section from top to bottom. The evaporation section includes a light collecting module and a seawater desalination module; the light collecting module includes at least two groups of angle-adjustable light collecting plates, which are connected to the base of the heat pipe type seawater desalination device through a bracket; the seawater desalination module is provided with a double-layer vacuum heat collecting tube, a water absorption evaporation layer and a water-proof breathable film in sequence from the outside to the inside; the inner layer of the double-layer vacuum heat collecting tube is coated with a light absorbing material at one end close to the water absorption evaporation layer; The connecting section serves as a connecting component for connecting and sealing the evaporation section and the condensation section; The condensation section is formed by a nested double-layer pipe structure, and the nested pipe structure forms two inner and outer chambers as independent condensing water chambers and cooling water chambers. A pipe and an outlet are arranged at the bottom to communicate with the outside.

2. The heat pipe seawater desalination device according to claim 1, characterized in that: The vacuum heat collecting tube is a double-layer vacuum glass tubular structure with a closed top. A light absorbing material is coated on one end of the inner glass side wall close to the water absorbing evaporation layer to receive the solar energy absorbed by the concentrating plate and convert it into heat energy.

3. The heat pipe seawater desalination device according to claim 2, characterized in that: The light absorbing material is a gradient aluminum-nitrogen composite coating; the coating thickness is 0.1-0.3 μm and the area is 0.10-1.0 m 2 .

4. The heat pipe seawater desalination device according to claim 1, characterized in that: The water absorption and evaporation layer is arranged on the inner side of the vacuum heat collecting tube; the water absorption and evaporation layer has a thickness of 1-3 mm and an area of ​​0.1-1.0 m 2 Porous carbon felt material.

5. The heat pipe seawater desalination device according to claim 1, characterized in that: The water-proof and breathable membrane is arranged on the inner side of the water-absorbing and evaporating layer facing the inside of the heat pipe type seawater desalination device substrate. The size of the water-proof and breathable membrane matches the water-absorbing and evaporating layer and is used to isolate seawater and allow water vapor to pass through.

6. The heat pipe seawater desalination device according to claim 1, characterized in that: The material of the water-proof and breathable membrane is polytetrafluoroethylene; the material of the connecting section is polytetrafluoroethylene.

7. The heat pipe seawater desalination device according to claim 1, characterized in that: In the double-layer pipe structure of the condensing section, the hollow structure sandwiched in the middle of the double-layer pipe structure forms a cooling water cavity, and a cooling water inlet and outlet are arranged at the bottom; the inner pipe forms a condensing water cavity for carrying the fresh water generated by the evaporating section.

8. The heat pipe seawater desalination device according to claim 7, characterized in that: A fresh water outlet is arranged at the bottom of the condensation water chamber; a pipeline for conveying seawater is connected to the middle of the double-layer pipeline structure, and the other end of the pipeline is connected to the water absorption and evaporation layer.

9. A method for desalinating seawater using the heat pipe desalination device according to any one of claims 1 to 8, characterized in that: The following steps are involved: S01: placing the heat pipe seawater desalination device outdoors in a place with sufficient sunshine; S02: Seawater is pumped in through the pipeline at the bottom of the heat pipe desalination device; S03: Seawater enters the water absorption and evaporation layer of the heat pipe desalination device through a pipeline, and the porous carbon felt material of the water absorption and evaporation layer fully absorbs the seawater by its own capillary force and is always in a state of saturated absorption of seawater; S04: The concentrating plate outside the base of the heat pipe desalination device and the light absorbing material coated in the double-layer vacuum heat collecting tube inside the base cooperate to absorb and amplify solar energy, converting solar energy into heat energy, so that the seawater adsorbed in the water absorption and evaporation layer in S03 evaporates to generate water vapor and enters the base of the heat pipe desalination device through the waterproof and breathable membrane; S05: cold water is introduced into the cooling water chamber of the heat pipe desalination device. The water vapor generated in S04 is transformed into condensed fresh water driven by the temperature difference between the evaporation section and the condensation section and falls into the condensation water chamber of the heat pipe desalination device, and is collected from the fresh water outlet.

10. The method according to claim 9, characterized in that The light absorption rate of the light absorbing material is 0.98; the thermal conductivity of the evaporation material is 0.09-0.13wm -1 k -1 .

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