Membrane assembly for membrane distillation and membrane distillation device and method based on semiconductor technology

Abstract

The invention discloses a membrane assembly for membrane distillation and a membrane distillation device and method based on a semiconductor technology. The device at least comprises a shell, a membrane assembly is arranged in the shell, the peripheral side of the membrane assembly and the shell are arranged in an air-tight sealing mode, and the shell is divided into a heating cavity and a refrigerating cavity which are not communicated with each other; a heating device is arranged in the heating cavity; a condensing device is arranged in the refrigeration cavity; the membrane assembly comprises two metal nets which are arranged at an interval, and a plurality of semiconductor refrigeration sheets are uniformly distributed between the two metal nets; the heating end of each semiconductor refrigeration sheet is arranged corresponding to the heating cavity, and the refrigeration end of each semiconductor refrigeration sheet is arranged corresponding to the refrigeration cavity; and hydrophobic microporous membranes are arranged on one sides, far away from the semiconductor refrigeration sheet, of the two metal nets. Compared with a traditional membrane distillation device, the device is simple in system, and the operation cost is low through the semiconductor refrigerator in the membrane assembly; by switching operation of the positive electrode and the negative electrode, pollution and blockage of the membrane distillation membrane assembly can be effectively relieved.

Description

Technical Field

[0001] The invention relates to a membrane component for membrane distillation, a membrane distillation device based on semiconductor technology and a method. Background Art

[0002] Membrane distillation is a new separation technology driven by vapor pressure difference. Compared with traditional distillation methods and other membrane separation technologies, it has the advantages of low operating pressure, low operating temperature, high separation efficiency, etc. It can make full use of heat sources such as solar energy, waste heat and residual heat. It is widely used in seawater desalination, preparation of ultrapure water, concentration, crystallization and separation of volatile substance aqueous solutions.

[0003] In the process of membrane distillation heat transfer, heat is first transferred from the feed liquid body with a higher temperature to the membrane surface on the feed side by heat convection. When the water molecules in the feed liquid vaporize on the membrane surface, they absorb heat near the membrane, causing the surface temperature of the membrane on the feed side to be lower than the temperature of the feed liquid body. The water vapor molecules pass through the membrane pores to reach the permeate side to condense and release heat, and then transfer to the cold side main solution by heat convection. Therefore, the surface temperature of the cold side membrane is higher than the main solution temperature. The temperature difference generated in this way causes a temperature boundary layer to form on both sides of the membrane, and then a certain temperature distribution is formed between the membrane surface and the feed liquid body. This phenomenon is called temperature polarization, which causes the temperature difference on both sides of the membrane to decrease, resulting in a significant decrease in the driving force of membrane distillation. Summary of the invention

[0004] In order to overcome the above-mentioned defects, the object of the present invention is to provide a membrane module for membrane distillation, a membrane distillation device and a method based on semiconductor technology.

[0005] To achieve the above object, the present invention provides a membrane distillation device based on semiconductor technology, the device at least comprising a shell, a membrane assembly is arranged in the shell, the membrane assembly is arranged to be hermetically sealed around the shell, and the shell is divided into a heat-generating chamber and a cooling chamber which are not connected to each other; a heating device is arranged in the heat-generating chamber; a condensing device is arranged in the cooling chamber;

[0006] The membrane assembly comprises: two metal meshes arranged at intervals, a plurality of semiconductor cooling sheets are evenly distributed between the two metal meshes; the heating end of each semiconductor cooling sheet is arranged corresponding to the heating cavity, and the cooling end of each semiconductor cooling sheet is arranged corresponding to the cooling cavity; a hydrophobic microporous membrane is arranged on the side of the two metal meshes far from the semiconductor cooling sheet.

[0007] Furthermore, a drainage pipe is arranged on the bottom shell between the two metal meshes.

[0008] Furthermore, a vibration device is provided on the shell at one side corresponding to the heating chamber.

[0009] Furthermore, the vibration device is an ultrasonic vibration device.

[0010] Furthermore, the heating device and the condensing device are respectively the hot end and the cold end of a separate semiconductor refrigerator.

[0011] To achieve the above-mentioned purpose, the membrane assembly for membrane distillation of the present invention comprises: a U-shaped or circular shell, with openings arranged on both sides of the shell, two metal meshes adapted to the shell arranged at intervals in the shell, and a plurality of semiconductor cooling sheets evenly distributed between the two metal meshes; the heating end of each semiconductor cooling sheet is arranged corresponding to the heating cavity, and the cooling end of each semiconductor cooling sheet is arranged corresponding to the cooling cavity; a hydrophobic microporous membrane is arranged on the side of the two metal meshes far from the semiconductor cooling sheet; and an airtight seal is arranged between the hydrophobic microporous membrane and the shell.

[0012] Furthermore, a drain outlet is provided on the shell between the two metal meshes.

[0013] To achieve the above object, the present invention provides a membrane distillation method based on semiconductor technology, wherein the method comprises:

[0014] 1) placing the hot end of the separate semiconductor refrigerator in a cavity on one side of the membrane distillation device to form a heating cavity, and placing the cold end of the separate semiconductor refrigerator in a cavity on the other side of the membrane distillation device to form a condensing cavity;

[0015] The raw liquid is supplied to the heating chamber and heated to 60-80 degrees by the hot end of the separated semiconductor refrigerator; its steam passes through the membrane assembly and is discharged from the condensing chamber;

[0016] 2) After running for one cycle, the positive and negative poles of the separated semiconductor refrigerator are switched, so that the original hot end of the separated semiconductor refrigerator becomes the cold end, and the original cold end becomes the hot end; that is, the original heating chamber becomes the condensing chamber, that is, the original condensing chamber becomes the heating chamber;

[0017] The raw liquid is supplied to the new heating chamber and heated to 60-80 degrees by the new hot end of the separated semiconductor refrigerator; its steam passes through the membrane assembly and is discharged from the new condensing chamber;

[0018] Over and over again.

[0019] Compared with traditional membrane distillation devices, the membrane distillation device based on semiconductor technology realized by the above technical solution has a simple system and no secondary pollution. It can effectively alleviate temperature polarization and effectively alleviate the fouling of membrane distillation membrane components. It also has the advantages of being green and environmentally friendly and having low operating costs. It can be used for seawater desalination, preparation of ultrapure water, concentration, crystallization and separation of aqueous solutions of volatile substances, etc. It is a widely used and environmentally friendly membrane separation technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1This is the schematic diagram of the semiconductor refrigerator;

[0021] Figure 2 For multiple Figure 1 Schematic diagram of semiconductor coolers in series.

[0022] Figure 3 for Figure 2 Schematic diagram of the semiconductor refrigerator after the cold end and hot end are separated.

[0023] Figure 4 It is a structural schematic diagram of the present invention.

[0024] Figure 5 for Figure 4 Cross-sectional view of the middle membrane assembly.

[0025] Figure 6 for Figure 4 An enlarged schematic diagram of .

[0026] Figure 7 Schematic diagram of the membrane assembly.

[0027] Explanation of the figure numbers: shell 1; membrane assembly 2; semiconductor refrigerator 21; metal mesh 22; hydrophobic microporous membrane 23; electrode plate 211; insulating heat dissipation substrate 212; power connection end 32 of the separate semiconductor refrigerator; the other end 31 of the separate semiconductor refrigerator; ultrasonic vibration 4. DETAILED DESCRIPTION

[0028] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0029] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0030] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] The semiconductor cooler (TEC) referred to in the present invention is also called a thermoelectric cooler, which is made by utilizing the Peltier effect of semiconductor materials. The so-called Peltier effect refers to the phenomenon that when a direct current passes through a galvanic couple composed of two semiconductor materials, one end absorbs heat and the other end releases heat.

[0033] Figure 1 and Figure 2 The schematic diagram of the semiconductor refrigerator is shown in the figure. As shown in the figure, it includes more than one P-type and N-type pairs (groups), which are connected together through upper and lower electrode plates 211 and sandwiched between two insulating heat dissipation substrates 212. By connecting positive and negative electricity to the two electrodes, a hot end and a cold end are formed at the upper and lower ends. Further, by exchanging the positive and negative electrodes on the two electrodes, the cold end and the hot end at the upper and lower ends can be exchanged.

[0034] Figure 3 is Figure 2 Further deformation based on Figure 2 The semiconductor part is cut in the middle and connected with electrodes, and the upper and lower parts are connected by wires, so as to realize the separation of the cold end (hot end) and the hot end (cold end); one end is the power connection end 32 of the separated semiconductor refrigerator; the other end 31 of the separated semiconductor refrigerator.

[0035] The present invention is realized based on the above principle. Figure 4 As shown, it at least comprises a shell 1, a membrane assembly 2 is arranged in the shell, the periphery of the membrane assembly is arranged in an airtight manner with the shell, and the shell is divided into a heat-generating chamber and a cooling chamber which are not connected to each other; a heating device is arranged in the heat-generating chamber; and a condensing device is arranged in the cooling chamber;

[0036] The membrane assembly 2 comprises: two metal meshes 22 arranged at intervals, a plurality of semiconductor cooling (devices) 21 are evenly distributed between the two metal meshes; the heating end of each semiconductor cooling piece is arranged corresponding to the heating cavity, and the cooling end of each semiconductor cooling piece is arranged corresponding to the cooling cavity; a hydrophobic microporous membrane 23 is arranged on the side of the two metal meshes far from the semiconductor cooling piece. In the above structure, the heat or cold generated at the two ends of the semiconductor cooling piece is respectively conducted to the metal meshes on both sides, and then evenly conducted to the hydrophobic microporous membrane 23 on the outside of the metal mesh through the metal mesh to overcome the polarization phenomenon.

[0037] The conventional membrane distillation technology system is complex, requiring not only a system for heating the stock solution but also a condensation system. Therefore, the heating device and the condensation device in the membrane distillation device of the present invention are the hot end (cold end) 31 and the cold end (hot end) 32 of the separate semiconductor refrigerator, respectively. In this way, the heating and cooling problems can be effectively solved by using one set of power supply.

[0038] Furthermore, a drainage pipe is arranged on the bottom shell between the two metal meshes.

[0039] Furthermore, an ultrasonic mixer is provided at the end of the hot end pool, and the raw liquid in the hot end pool can be completely mixed by ultrasonic vibration, and the raw liquid temperature is maintained between 60-80°C, which can save energy and make the raw liquid generate a large amount of water vapor on the surface of the hot end membrane.

[0040] The membrane distillation membrane module of the present invention is as follows Figure 7 As shown, it includes a U-shaped or circular shell, with openings on both sides of the shell, two metal meshes adapted to the shell are arranged at intervals in the shell, and a plurality of semiconductor cooling plates are evenly distributed between the two metal meshes; the heating end of each semiconductor cooling plate is arranged corresponding to the heating cavity, and the cooling end of each semiconductor cooling plate is arranged corresponding to the cooling cavity; a hydrophobic microporous membrane is arranged on the side of the two metal meshes far from the semiconductor cooling plate; and an airtight seal is arranged between the hydrophobic microporous membrane and the shell.

[0041] Furthermore, a drain outlet is provided on the shell between the two metal meshes.

[0042] As a key component in the membrane distillation process, the performance of the hydrophobic microporous membrane determines the efficiency of membrane distillation to a large extent. In the application of membrane distillation, the water body to be treated is often complex, and the surface of the hydrophobic membrane is easily contaminated by substances such as surfactants and inorganic salt scaling. These pollutants will clog the membrane pores, reduce the membrane separation efficiency, and even reduce the surface energy of the membrane, destroying the hydrophobic barrier, resulting in membrane wetting, and ultimately causing the feed liquid to penetrate the hydrophobic microporous membrane, rendering the membrane distillation ineffective.

[0043] The membrane distillation method based on semiconductor technology of the present invention comprises:

[0044] 1) placing the hot end of the separate semiconductor refrigerator in a cavity on one side of the membrane distillation device to form a heating cavity, and placing the cold end of the separate semiconductor refrigerator in a cavity on the other side of the membrane distillation device to form a condensing cavity;

[0045] The raw liquid is supplied to the heating chamber and heated to 60-80 degrees by the hot end of the separated semiconductor refrigerator; its steam passes through the membrane assembly and is discharged from the condensing chamber;

[0046] 2) After running for one cycle, the positive and negative poles of the separated semiconductor refrigerator are switched, so that the original hot end of the separated semiconductor refrigerator becomes the cold end, and the original cold end becomes the hot end; that is, the original heating chamber becomes the condensing chamber, that is, the original condensing chamber becomes the heating chamber;

[0047] The raw liquid is supplied to the new heating chamber and heated to 60-80 degrees by the new hot end of the separated semiconductor refrigerator; its steam passes through the membrane assembly and is discharged from the new condensing chamber;

[0048] Repeatedly. The hot chamber and the cold chamber can be used alternately; during normal operation, the raw liquid enters from the lower end of the hot end tank and exits from the upper end of the cold end tank. After the device has been running for a period of time, in order to alleviate the fouling on the membrane surface, the positive and negative poles of the photovoltaic DC power supply are switched, and the raw liquid enters from the upper end of the cold end tank and exits from the lower end of the hot end tank. At this time, the steam can flow through the membrane assembly in a reverse direction, which can backwash the membrane assembly.

[0049] The present invention is described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present invention. Many other changes and modifications that do not depart from the concept and scope of the present invention should be regarded as the protection scope of the present invention.

[0050] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0051] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A membrane distillation device based on semiconductor technology, characterized in that: The device at least comprises a shell, a membrane assembly is arranged in the shell, and the periphery of the membrane assembly is arranged to be airtightly sealed with the shell, so as to separate the shell into a heat-generating chamber and a cooling chamber which are not connected to each other; A heating device is provided in the heating chamber; a condensing device is provided in the cooling chamber; The membrane assembly comprises: two metal meshes arranged at intervals, and a plurality of semiconductor cooling sheets are evenly distributed between the two metal meshes; The heating end of each semiconductor cooling sheet is arranged corresponding to the heating cavity, and the cooling end of each semiconductor cooling sheet is arranged corresponding to the cooling cavity; a hydrophobic microporous membrane is arranged on one side of the two metal nets far from the semiconductor cooling sheet.

2. The membrane distillation device based on semiconductor technology according to claim 1, characterized in that: A drainage pipe is arranged on the bottom shell between the two metal meshes.

3. The membrane distillation device based on semiconductor technology as claimed in claim 1, characterized in that: A vibration device is arranged on one side of the shell corresponding to the heating chamber.

4. A membrane distillation device based on semiconductor technology according to claim 3, characterized in that: The vibration device is an ultrasonic vibration device.

5. The membrane distillation device based on semiconductor technology as claimed in claim 1, characterized in that: The heating device and the condensing device are respectively the hot end and the cold end of the separated semiconductor refrigerator.

6. A membrane module for membrane distillation, characterized in that: include: A U-shaped or circular shell, with openings on both sides of the shell, two metal meshes adapted to the shell are arranged at intervals in the shell, and a plurality of semiconductor cooling plates are evenly distributed between the two metal meshes; the heating end of each semiconductor cooling plate is arranged corresponding to the heating cavity, and the cooling end of each semiconductor cooling plate is arranged corresponding to the cooling cavity; a hydrophobic microporous membrane is arranged on the side of the two metal meshes far from the semiconductor cooling plate; and an airtight seal is arranged between the hydrophobic microporous membrane and the shell.

7. The membrane module for membrane distillation according to claim 6, characterized in that: A drainage port is arranged on the shell body between the two metal meshes.

8. A membrane distillation method based on semiconductor technology, characterized in that: The method includes: 1) placing the hot end of the separate semiconductor refrigeration element in a cavity on one side of the membrane distillation device to form a heating cavity, and placing the cold end of the separate semiconductor refrigeration element in a cavity on the other side of the membrane distillation device to form a condensing cavity; The raw liquid is supplied to the heating chamber and heated to 60-80 degrees by the hot end of the separated semiconductor refrigeration element; its steam passes through the membrane assembly and is discharged from the condensation chamber; 2) After one cycle of operation, the positive and negative poles of the separated semiconductor refrigeration element are switched, so that the original hot end of the separated semiconductor refrigeration element becomes the cold end, and the original cold end becomes the hot end; that is, the original heating chamber becomes the condensing chamber, that is, the original condensing chamber becomes the heating chamber; The raw liquid is supplied to the new heating chamber and heated to 60-80 degrees by the new hot end of the separated semiconductor refrigeration element; its steam passes through the membrane assembly and is discharged from the new condensing chamber; Over and over again.

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