A wound ultrafiltration membrane assembly and preparation method thereof

Abstract

The present application discloses a wound ultrafiltration membrane assembly and a preparation method thereof, wherein the wound ultrafiltration membrane assembly comprises a wound filter element; the wound filter element is wound by a belt-shaped filter unit, and the belt-shaped filter unit is formed by hollow fiber membrane filaments arranged and fixed. The present application adopts a mature and effective winding technology to wind a small amount of membrane bundles into a cylindrical or spindle shape; the hollow fibers are supported by their own membrane walls, and the formed membrane cylinder has extremely high strength and ductility, is not affected by external conditions and internal and external pressures, and has close contact and extremely high space utilization.

Description

Technical Field

[0001] The present application belongs to the technical field of ultrafiltration membrane components, and specifically relates to a wound ultrafiltration membrane component and a preparation method thereof. Background Art

[0002] Ultrafiltration membrane purification technology adopts a high-precision pure physical filtering principle with a filtering accuracy of 0.1 to 0.001 microns. It does not add any chemical substances and relies on the dense micropores on the surface of the ultrafiltration membrane to screen and intercept harmful substances, thereby achieving the effect of filtering, purifying and purifying. It intercepts rust, particles, bacteria, colloids and some organic matter in the water, keeps the pH value of the produced water unchanged, and retains the trace minerals and trace dissolved oxygen needed by the human body in the water.

[0003] Hollow fiber ultrafiltration membrane assembly is a type of ultrafiltration membrane. It is the most mature and advanced technology in ultrafiltration technology. The outer diameter of the hollow fiber is 0.5-2.0nm, the inner diameter is 0.3-1.4nm, and the hollow fiber tube wall is covered with micropores. The pore size is expressed by the molecular weight of the substance that can be retained, and the molecular weight can reach thousands to hundreds of thousands. The raw water flows under pressure on the outside or inner cavity of the hollow fiber, forming external pressure type and internal pressure type respectively. Ultrafiltration is a dynamic filtration process. The retained substances can be discharged with the concentrated water, and the membrane surface will not be blocked, and it can operate continuously for a long time. Ultrafiltration membrane is one of the earliest developed polymer separation membranes.

[0004] Ultrafiltration membrane filtration can be achieved by relying only on the pressure of tap water itself, without the need for electricity or pressurization. It has the characteristics of low pressure, no phase change, low energy consumption, and less wastewater discharge, which is safe and energy-saving. In addition, since ultrafiltration membrane filtration does not require electricity and pressurization, the equipment is simple and easy to install, the water flux is large, and no supporting equipment such as water storage tanks is required. Ultrafiltration membrane filtration has the function of flushing and draining. By flushing the ultrafiltration membrane filaments forward and backward, the trapped pollutants can be flushed out and the service life of the ultrafiltration membrane filaments can be extended.

[0005] At present, the ultrafiltration membranes used for water treatment on the market are mainly hollow fibers.

[0006] The hollow fiber ultrafiltration membrane assembly can be very small. Since there is no need for a support body, hundreds to tens of thousands of hollow fibers can be installed in the assembly. The packing density is large and the water production is high. However, the disadvantage is that in order to improve the membrane surface decontamination and increase the service life of the membrane, soda-water backwashing is often used, which leads to the phenomenon of broken wires at the end of the membrane wire. Once the membrane wire is broken, it cannot be updated. The commonly used hollow fiber ultrafiltration membrane assembly is to set a central tube in the cylinder, place the ultrafiltration membrane between the inner wall of the cylinder and the central tube, and fix it with resin at both ends of the cylinder. This structure is generally arranged side by side at equal distances, and the layout is not reasonable enough, which is easy to produce cleaning dead corners, and it is easy to damage and deform the membrane wire and unevenly distribute it. At the same time, as the membrane assembly is used for a longer time, impurities will remain in the membrane assembly, which needs to be cleaned regularly. It can be seen that the main problems faced by hollow fiber ultrafiltration membranes in applications are membrane pollution and broken wires. These problems not only increase the investment and operation and maintenance burden, but also limit the application field of ultrafiltration technology.

[0007] In response to the problems that have arisen, some people have proposed different solutions. For example, Patent 200820011362 provides a new type of ultrafiltration membrane assembly, which places the ultrafiltration membrane wire core in a tubular pressure-resistant shell, installs a porous baffle on the inner side of the backwash liquid inlet nozzle, and seals each gap with a sealant to bond each assembly together, thereby reducing the wire breakage rate, improving the membrane filtration capacity during the backwash process, and improving the backwash recovery effect. Patent 201120552759 provides an external pressure hollow fiber membrane ultrafiltration assembly with an anti-pollution structure, which is interspersed with multiple variable-section turbulence promoters along the length direction of the hollow fiber ultrafiltration membrane wire, so that membrane pollution and concentration polarization phenomena are effectively controlled, the filtration efficiency is improved, and the service life of the membrane assembly is extended. Patent 201120517955 provides a hollow fiber ultrafiltration membrane assembly with an improved central conduit structure, which is to stagger the outlet holes on the surface of the central conduit, which is not easy to produce dirt dead corners and enhance the cleaning effect. Patent 201110179385 relates to a hollow fiber ultrafiltration membrane assembly with a grid, in which a grid plate is fixed in the axial direction of the central conduit, which plays a certain role in fixing and supporting the fiber ultrafiltration membrane fixed inside the pressure-bearing shell, which can reduce the deformation of the membrane during backwashing and extend the service life of the membrane. Patent 201110179369 provides a hollow fiber ultrafiltration membrane assembly with a reinforcement plate, which is characterized in that a central baffle is fixed to the inner wall of the membrane assembly. The central baffle in the membrane shell has the effect of strengthening the verticality of the membrane wire, and it is not easy to produce dirt residue on the surface of the membrane assembly during normal operation and enhance the cleaning effect.

[0008] The existing hollow fiber membrane modules generally have the following technical problems:

[0009] 1) Hollow fiber outer diameter: 0.5-2.0nm, inner diameter: 0.3-1.4nm. Single hollow fiber strength

[0010] Small, in the case of frequent backwashing, wire breakage is likely to occur.

[0011] 2) Occasional pressure fluctuations will increase the damage to the hollow fibers and easily cause fiber breakage.

[0012] 3) Each hollow fiber membrane module is filled with a large number of membrane fibers. When a small amount of broken fibers occur, they cannot be discovered in time. Until large-scale broken fibers occur, continuous pollution to the water body has already been caused.

[0013] 4) To solve the problem of broken wires, the pure water flux of membrane wires with support mesh is relatively low, and the coating layer is prone to fall off from the support layer. Summary of the invention

[0014] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a wound ultrafiltration membrane assembly and a method for preparing the same.

[0015] In the first aspect, the present application provides a wound ultrafiltration membrane assembly, including a wound filter element; the wound filter element is wound by a strip filter unit; the strip filter unit is formed by arranging and fixing hollow fiber membrane filaments. The width of the strip filter unit is much smaller than the length of the central tube, and the strip filter unit is gradually wound outside the central tube in a regular or irregular spiral manner along the length direction. Compared with conventional ultrafiltration membrane assemblies using the same hollow fiber membrane filaments, the strength of the overall filter unit is greatly enhanced by the winding support between the membrane filaments while achieving the same filtration area and effect. Conventional filtration operations such as air washing, air-water backwashing, pressurization, irregular pressure fluctuations, etc. have little impact on the formed wound filter unit, and the membrane filaments therein will only produce extremely small deformations, which reduces the impact of the cleaning operation on the deformation of the membrane filaments, the membrane filtration area and the filtration pore size, and can effectively alleviate or even avoid the occurrence of broken wires. As the operating pressure increases, the actual number of membrane filaments in the filtration unit decreases, and occasional membrane filament breakage occurs, which will cause a significant change in the operating pressure, and then the membrane assembly will be shut down in time to avoid pollution of the entire water treatment system. The strip filter unit is wound and formed, and the filling density is greatly increased, which greatly compresses the membrane assembly space. After winding, the membrane filaments form tiny gaps, and the filtered water flow can pass smoothly through these gaps. In order to help the new structure overcome the water-passing force, it is only necessary to provide the membrane assembly with an additional pressure of 0.005-0.02atm.

[0016] As a preferred solution, the extension direction of the belt-shaped filter unit is consistent with the extension direction of the hollow fiber membrane. That is, the hollow fiber membrane is wound outside the central cylinder in a direction perpendicular or oblique to the axis of the central cylinder, rather than making the hollow fiber membrane parallel to the axis of the central cylinder like ordinary membrane modules.

[0017] This arrangement reduces losses and improves utilization. In common ultrafiltration membrane components, more than 6,000 ultrafiltration membrane fibers of more than 1 meter in length are used to obtain a filtration area of ​​50 square meters. For the same filtration area, this application can use 64 190-meter-long membrane fibers. This reduces the cutting process and reduces the consumption of membrane fibers.

[0018] As a preferred solution, each hollow fiber membrane filament constituting the strip filter unit is provided with a fixed node at a certain distance in the length direction. Firstly, the existence of the fixed node allows the strip filter unit to be cut at different positions, and the filter area of ​​the filter element can be achieved by adjusting the winding length of the filter unit; secondly, the fixed node can also control the winding shape of the strip filter unit to a certain extent, reducing the deformation of the membrane filament.

[0019] As a preferred solution, the ends of the belt-shaped filter units are sealed by molten quick connectors.

[0020] As a preferred embodiment, the belt-shaped filtration unit is formed by 20-100 hollow fiber membranes arranged in 1-2 layers.

[0021] As a preferred solution, the water inlet and outlet of the wound filter element and the wound ultrafiltration membrane assembly, namely the quick connector connection, are fixed by coating packaging glue.

[0022] As a preferred solution, the wound filter element is in a cylindrical or spindle shape. Theoretically, the wound filter element can be wound into any regular or irregular shape by a belt-shaped filter unit, but for reasons of packing density, structural stability, etc., the wound filter element is usually wound into a cylindrical or spindle shape.

[0023] In a second aspect, the present application also provides a filter or a water purifier comprising the above-mentioned wound ultrafiltration membrane assembly.

[0024] In a third aspect, the present application also provides a method for preparing a wound ultrafiltration membrane assembly, comprising the following steps:

[0025] Arrange 20-100 hollow fiber membranes in sequence to form a belt-shaped filtration unit;

[0026] The belt-shaped filter unit is uniformly wound into a cylinder or spindle shape along the central cylinder of the membrane assembly, and a stable tightness and a fixed winding speed are maintained to form a wound filter element;

[0027] The ends of the belt-shaped filter unit are sealed and fixed by hot-melt quick connectors;

[0028] The connection of the wound filter element quick connector is sealed by coating with fixing glue, and is equipped with a connector package to obtain an independent wound ultrafiltration membrane assembly.

[0029] As a preferred embodiment, the preparation method further comprises adjusting the filtration area of ​​the wound filter element by adjusting the winding length of the filtration unit.

[0030] The advantages and positive effects of the present invention are as follows: the present invention proposes a wound ultrafiltration membrane assembly, which adopts mature and effective winding technology to wind a small amount of membrane bundles into a cylindrical or

[0031] Spindle-shaped; the hollow fiber is supported by its own membrane wall. The formed membrane cylinder has extremely high strength and ductility, is not affected by external conditions and internal and external pressures, has close contact, and has extremely high space utilization.

[0032] In addition to the technical problems solved by the present application, the technical features that constitute the technical solutions, and the advantages brought by the technical features of these technical solutions described above, other technical problems that can be solved by the present application, other technical features included in the technical solutions, and the advantages brought by these technical features will be further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0034] Figure 1 A schematic diagram of the structure of a wound ultrafiltration membrane assembly provided in an embodiment of the present application; Figure 2 This is a schematic diagram of the structure of a belt-shaped filter unit provided in an embodiment of the present application.

[0035] In the figure: 1. Belt filter unit; 2. Center tube; 3. Hollow fiber membrane; 4. Fixed node. DETAILED DESCRIPTION

[0036] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0037] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0038] Example 1

[0039] Please refer to Figure 1 and Figure 2This embodiment provides a wound ultrafiltration membrane assembly, including a wound filter element; the wound filter element is cylindrical, and is formed by winding a strip filter unit 1 on a central tube 2. The strip filter unit 1 includes 64 hollow fiber membranes 3, which are neatly arranged in 2 layers; the extension direction of the strip filter unit 1 is consistent with the extension direction of the hollow fiber membranes 3, and a fixed node 4 is provided at a certain interval to fix all the hollow fiber membranes 3 together,

[0040] Prevent loosening. The end of the belt filter unit 1 is fixed or sealed by melting. The inlet and outlet of the wound filter element and the wound ultrafiltration membrane assembly are fixed by coating with packaging glue.

[0041] This embodiment also provides a water purifier or filter including the above-mentioned wound ultrafiltration membrane assembly.

[0042] This embodiment also provides a method for preparing the above-mentioned wound ultrafiltration membrane assembly:

[0043] The ultrafiltration membrane filter element of the present invention adopts hollow fiber ultrafiltration membrane filaments; 64 or more membrane filaments are arranged in sequence to form a strip-shaped filter unit; the ends of the strip-shaped filter unit are sealed and fixed by hot melting as needed. The strip-shaped filter unit is uniformly wound into a cylindrical shape along the central cylinder of the membrane assembly, and a stable tightness and a fixed winding speed are maintained; after the coiling is formed, a cylindrical filter element is formed, and the membrane core is encapsulated to form an independent ultrafiltration membrane assembly; the end of the strip-shaped filter unit is connected to the water inlet and outlet of the membrane assembly, and a fixing glue is applied to the connection to seal it.

[0044] The filter area of ​​the filter element can be achieved by adjusting the winding length of the filter unit.

[0045] In this embodiment, the belt-shaped filter unit uses 24 hollow fiber membranes arranged in one layer, and the wound filter element is spindle-shaped, that is, a rotating body with a thicker middle and thinner ends. The rest of the wound ultrafiltration membrane assembly is the same as in Example 1, and the preparation method is referred to in Example 1.

[0046] In other embodiments, the belt-shaped filter unit may also use other numbers of hollow fiber membranes, such as 20-100, arranged in other numbers of layers, and the wound filter element may also use other shapes.

[0047] The wound ultrafiltration membrane assembly provided in the present application can be formed by manual winding, and the filtration flux is the same as that of a conventional membrane assembly. The winding of a large membrane assembly needs to be carried out by a winding device, and the tension and the number of winding layers need to be confirmed through practice.

[0048] Compared with the common ultrafiltration membrane assembly in the prior art, the wound ultrafiltration membrane assembly provided in the present application has the following obvious advantages:

[0049] 1) The same type of hollow fiber membrane is used, which greatly enhances the strength of the overall ultrafiltration membrane without affecting the filtration area and effect. Conventional filtration operations such as pressurization, irregular pressure fluctuations, air washing, and air-water backwashing will only cause extremely small deformation of the membrane fibers in the wound ultrafiltration membrane assembly, which can avoid the occurrence of broken fibers in actual operation.

[0050] 2) Reduced loss and improved utilization rate; ordinary ultrafiltration membrane components use more than 6,000 ultrafiltration membrane fibers with a length of more than 1 meter; for the same filtration area, this application only requires 64 membrane fibers with a length of 190 meters

[0051] It reduces the cutting process and reduces the consumption of membrane wire.

[0052] 3) The filter element is wound and formed, which greatly compresses the filter membrane space; the same membrane assembly, the filling density is greatly improved. The wound ultrafiltration membrane assembly is a pressure-type membrane assembly. The tiny gaps between the membrane fibers can provide sufficient water flow channels. Only an additional 0.02atm (2kPa) air pressure is required for the membrane assembly to help the new structure overcome the water flow assistance.

[0053] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A wound ultrafiltration membrane assembly, characterized in that: It includes a wound filter element; the wound filter The core is formed by winding a belt-shaped filter unit; the belt-shaped filter unit is formed by arranging and fixing hollow fiber membrane wires; The width of the belt filter unit is much smaller than the length of the center tube. Regular or irregular spirals are gradually wound around the central tube; The extension direction of the belt filter unit is consistent with the extension direction of the hollow fiber membrane. Winding outside the center tube in a direction oblique to the axis of the center tube; The belt-shaped filter unit is formed by 20-100 hollow fiber membranes arranged in 1-2 layers; The wound filter element is cylindrical or spindle-shaped; The end of the belt-shaped filter unit is sealed by a molten quick connector; Each hollow fiber membrane filament constituting the strip-shaped filter unit is provided with a fixed node at a certain interval in the length direction, and the fixed node controls the winding shape of the strip-shaped filter unit.

2. The wound ultrafiltration membrane assembly according to claim 1, characterized in that: The wound filter The core and the water inlet and outlet of the wound ultrafiltration membrane assembly are fixed by coating packaging glue.

3. A filter or water purifier comprising the wound ultrafiltration membrane assembly according to any one of claims 1 to 2 device.

4. A method for preparing a wound ultrafiltration membrane assembly, characterized in that: The following steps are involved: Arrange 20-100 hollow fiber membranes in sequence to form a belt-shaped filtration unit; The strip-shaped filtration unit is uniformly wound into a cylindrical or spindle shape along the central cylinder of the membrane assembly and kept stable. A certain tightness and a fixed winding speed form a winding filter element; The ends of the belt-shaped filter unit are sealed and fixed by hot-melt quick connectors; The connection of the spiral filter element quick connector is sealed by applying fixing glue and equipped with a connector seal. The device is installed as an independent wound ultrafiltration membrane assembly.

5. The method for preparing a wound ultrafiltration membrane assembly according to claim 4, characterized in that: return The method comprises adjusting the filtering area of ​​the wound filter element by adjusting the winding length of the filter unit.

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